2024-03-28T13:18:39Zhttps://kuscholarworks.ku.edu/oai/requestoai:kuscholarworks.ku.edu:1808/85162020-08-27T14:26:16Zcom_1808_231com_1808_1260col_1808_18153col_1808_7158
Fletcher, John H.
2011-11-23T16:48:00Z
2011-11-23T16:48:00Z
1913
http://hdl.handle.net/1808/8516
en_US
openAccess
This work is in the public domain according to U.S. copyright law and is available for users to copy, use, and redistribute in part or in whole. No known restrictions apply to the work.
Appraisal Seattle, Renton and Southern Railway Company
Thesis
oai:kuscholarworks.ku.edu:1808/19772020-07-15T12:08:03Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Morozov, Serhiy
2008-03-01T15:13:52Z
2008-03-01T15:13:52Z
2007-12-13
http://dissertations.umi.com/ku:2323
http://hdl.handle.net/1808/1977
Hierarchical data structures are an important aspect of many computer science fields including data mining, terrain modeling, and image analysis. A good representation of such data accurately captures the parent-child and ancestor-descendent relationships between nodes. There exist a number of different ways to capture and manage hierarchical data while preserving such relationships. For instance, one may use a custom system designed for a specific kind of hierarchy. Object oriented databases may also be used to model hierarchical data. Relational database systems, on the other hand, add an additional benefit of mature mathematical theory, reliable implementations, superior functionality and scalability. Relational databases were not originally designed with hierarchical data management in mind. As a result, abstract information can not be natively stored in database relations. Database labeling schemes resolve this issue by labeling all nodes in a way that reveals their relationships. Labels usually encode the node's position in a hierarchy as a number or a string that can be stored, indexed, searched, and retrieved from a database. Many different labeling schemes have been developed in the past. All of them may be classified into three broad categories: recursive expansion, materialized path, and nested sets. Each model has its strengths and weaknesses. Each model implementation attempts to reduce the number of weaknesses inherent to the respective model. One of the most prominent implementations of the materialized path model uses the unique characteristics of prime numbers for its labeling purposes. However, the performance and space utilization of this prime number labeling scheme could be significantly improved. This research introduces a new scheme called reusable prime number labeling (rPNL) that reduces the effects of the mentioned weaknesses. The proposed scheme advantage is discussed in detail, proven mathematically, and experimentally confirmed.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Computer science
Prime Number-Based Hierarchical Data Labeling Scheme for Relational Databases
Thesis
oai:kuscholarworks.ku.edu:1808/197222017-12-08T21:31:50Zcom_1808_231com_1808_1260col_1808_18153col_1808_7158
Albers, George Rockwell
2016-01-06T17:16:23Z
2016-01-06T17:16:23Z
1916
http://hdl.handle.net/1808/19722
openAccess
This work is in the public domain according to U.S. copyright law and is available for users to copy, use, and redistribute in part or in whole. No known restrictions apply to the work.
Electrostatic dust precipitation and the Miami smelter
Thesis
oai:kuscholarworks.ku.edu:1808/41632018-01-31T20:08:15Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Mohammadi, Zahra
2008-09-15T03:12:39Z
2008-09-15T03:12:39Z
2008-07-17
http://dissertations.umi.com/ku:2641
http://hdl.handle.net/1808/4163
Magnetic nanoparticles that display high saturation magnetization and high magnetic susceptibility with a size less than 200 nm are of great interest for medical applications. Investigations of magnetic nanoparticles have been increasing over the last decade. Magnetite nanoparticles are particularly desirable since the biocompatibility of these particles has already been proven. Several synthetic and natural polymers have been employed to stabilize magnetite nanoparticles and enhance their function in vivo. The goal of this work has been to develop a unique methodology for synthesizing magnetite within polymer nanoparticle dispersions so that the resultant magnetite-polymer particles may be used in a range of biomedical applications, specifically as an MRI contrast agent. A method was developed for preparing ≈150 nm polyvinylamine (PVAm) nanoparticles containing iron oxide. These polymeric nanoparticles offer colloidal stability and reactive primary amines for drug conjugation or surface modification. The polymer-magnetite nanoparticles described in this thesis exhibited a maximum of 12% wt. magnetite and a saturation magnetization of ~30 emu/mg. Transmission electron microscopy (TEM) images showed that the dispersions contained ≈100 to 150 nm diameter PVAm nanoparticles incorporated with iron oxide particles with a size less than ≈10 nm. The ability to synthesize iron oxide inside functionalized polymeric nanoparticles offers an effective approach to prevent nanoparticle agglomeration and the potential to enable ligand grafting. Stabilized magnetic PVAm nanoparticles may provide a unique synthetic approach to enhance MRI contrast and may offer a platform for molecular imaging.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Biomedical engineering
In Situe Synthesis of Iron Oxide within Polyvinylamine nanoparticles
Thesis
oai:kuscholarworks.ku.edu:1808/40712018-01-31T20:08:15Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Sivakumar, Mutharasu
2008-08-05T13:01:57Z
2008-08-05T13:01:57Z
2008-02-01
http://dissertations.umi.com/ku:2383
http://hdl.handle.net/1808/4071
Each year, about 76 million people contract a food borne illness in the United States; about 325,000 require hospitalization; and about 5,000 die. Tracking goods throughout the food supply chain increases the efficiency of recall of tainted goods and thus will help reducing food borne illness. Passive UHF RFID has been widely accepted to be a technology capable of increasing supply chain efficiency. Passive UHF RFID tags designed for supply chain application are tuned to work well on corrugated fiberboard boxes that are ubiquitous in the supply chain. Commercially available passive UHF RFID tags are either sensitive to the content/environmental conditions of the corrugated fiberboard box or economically unfeasible. In this thesis we propose a novel dual-resonant planar UHF RFID microstrip antenna designed to be both insensitive to the content/environmental conditions of the corrugated fiberboard box and economically feasible. We provide simulated performances and experimental validations to show that the proposed microstrip antenna design is a viable and technically superior solution compared to conventional stripline dipole antennas widely used in commodity tags.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Electronics and electrical engineering
Uhf rfid
Microstrip antenna
Dual resonant
Cold chain
A Dual Resonant Microstrip Antenna for UHF RFID in the Cold Chain Using Corrugated Fiberboard as a Substrate
Thesis
oai:kuscholarworks.ku.edu:1808/81822020-08-11T14:52:40Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Ruiz, Marc
2011-10-09T13:49:50Z
2011-10-09T13:49:50Z
2011-05-31
http://dissertations.umi.com/ku:11630
http://hdl.handle.net/1808/8182
Biped robots are desired as the ideal solution over wheel vehicles when traversing over rough terrain due to the simplicity and efficiency when mimicking the natural and dynamic motion of a human gait. The Intelligent Systems and Automation Laboratory (ISAL) at the University of Kansas designed and built a three legged 2D biped walking robot to establish a testbed for future testing. This paper focuses on the development and testing of a novel hip joint that allows actuation with the ability to remain passive. This study was completed concurrently with the development of a full robot as part of other projects. The biped robot, known as the Jaywalker, is comprised of two main actuation systems: the Hybrid Parallel Ankle Actuator (HPAA) and the Hip Ratchet System (HRS). This study focused on the design and testing of the HRS which achieves hip actuation through the use of a locking mechanism integrated into each hip joint that couples the legs to a shared drive system. The ability to lock and unlock the hip joint through the HRS enables the Jaywalker to function in passive or actuated states at the hips. Testing of the HRS was conducted in both passive and actuated states on the Jaywalker testbed. Testing of the hip provided proof in the concept of using a single drive in combination with a ratchet mechanism to actuate the hip while providing a passive option. The HRS also provided the capability to vary step lengths future testing that requires turning, rough terrain, and stair climbing.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Mechanical engineering
Mechanics
Robotics
Biped
Hip
Hrs
Passive
Ratchet
Robot
ACTIVE HIP ACTUATION FOR WALKING BIPED WITH PASSIVE OPTION
Thesis
oai:kuscholarworks.ku.edu:1808/101942018-01-31T20:08:10Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Nagati, Amr Daniel
2012-10-27T09:59:24Z
2012-10-27T09:59:24Z
2012-08-31
http://dissertations.umi.com/ku:12266
http://hdl.handle.net/1808/10194
Several studies have identified distortion-induced fatigue as the leading cause of cracks in steel bridges built prior to the mid-1980s. Experimental and computer simulations of 914-mm (36-in.) deep girder-cross frame subassemblies subjected to cyclic loading were carried out to study the effects of distortion-induced fatigue and to evaluate the effectiveness of various retrofit measures. Previous repair methods for distortion-induced fatigue damage have attempted to reduce the stress demand at the critical web-gap region by increasing the flexibility of the girder web in the out-of-plane direction or by restraining the lateral motion of the web by fixing the connection stiffener to the girder flange. A new approach was investigated in this study intended to reduce the stress demand in the web-gap region by re-distributing the out-of-plane force transferred through the girder-cross frame connection over a larger area of the girder web. A new retrofit measure is proposed based on this approach, which consists of adding steel angles connecting the girder web and the connection plate (CP), and a steel plate on the back side of the girder web to distribute the lateral force over a wider region of the web. Experimental and computer simulation results are presented showing that this repair method is very effective in preventing the growth of horseshoe-shaped cracks around the web cross-frame connection and of horizontal cracks near the junction between the flange and web.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Civil engineering
Bridge
Cfrp
Distortion
Fatigue
Load cell
Retrofit
Repair of Steel Bridge Girders Damaged by Distortion-Induced Fatigue
Thesis
oai:kuscholarworks.ku.edu:1808/209292018-01-31T20:07:48Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Al Aziz, Masud
2016-06-03T19:02:23Z
2016-06-03T19:02:23Z
2015-12-31
http://dissertations.umi.com/ku:14366
http://hdl.handle.net/1808/20929
The reliance of Unmanned Aerial Vehicles (UAVs) on Global Navigation Satellite System (GNSS) for autonomous operation represents a significant vulnerability to their reliable and secure operation due to signal interference, both incidental (e.g. terrain shadowing, ionospheric scintillation) and malicious (e.g. jamming, spoofing). An accurate and reliable alternative UAV navigation system is proposed that exploits Signals of Opportunity (SOP) thus offering superior signal strength and spatial diversity compared to satellite signals. Given prior knowledge of the transmitter's position and signal characteristics, the proposed technique utilizes triangulation to estimate the receiver's position. Dual antenna interferometry provides the received signals' Angle of Arrival (AoA) required for triangulation. Reliance on precise knowledge of the antenna system's orientation is removed by combining AoAs from different transmitters to obtain a differential Angles of Arrival (dAoAs). Analysis, simulation, and ground-based experimental techniques are used to characterize system performance; a path to miniaturized system integration is also presented. Results from these ground-based experiments show that when the received signal-to-noise ratio (SNR) is above about 45 dB (typically in within 30 km of the transmitters), the proposed method estimates the receiver's position uncertainty range from less than 20 m to about 60 m with an update rate of 10 Hz.
en
openAccess
Copyright held by the author.
Electrical engineering
Navigation for UAVs using Signals of Opportunity
Dissertation
oai:kuscholarworks.ku.edu:1808/304772021-03-05T16:54:48Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Patel, Akshay Dinesh
2020-06-14T21:02:37Z
2020-06-14T21:02:37Z
2019-12-31
http://dissertations.umi.com/ku:16842
http://hdl.handle.net/1808/30477
https://orcid.org/0000-0002-7710-8680
The aim of the study was to obtain Capacity adjustment factors and Break points which can be utilized for Highway Capacity Manual (HCM6) methodology in obtaining Level of Service for freeways when Connected and Autonomous Vehicles (CAVs) are present inside the traffic stream. Accordingly, various two-lane heterogeneous flow scenarios were modelled which included variations in free-flow speed and percent of heavy vehicles wherein the possible impact of the CAVs on the current traffic system was analyzed. Each scenario was first calibrated inside VISSIM to replicate the results from HCM6 and later CAVs were introduced in various proportions inside the traffic stream of conventional vehicles to access performance improvements using VISSIM. It was concluded that CAVs do improve system capacity and resulted in longer free-flow phase, which is a direct effect of the increased road capacity. Up to 25% CAV-penetration rate, the road capacity increased gradually and beyond 25%, the growth rate was largely decided by the improved capability of the CAVs compared to conventional vehicles. An improved capability corresponded to a higher capacity growth rate and a higher capacity. CAVs with higher penetration rates also resulted in longer free-flow phases but only a few of the scenarios saw a minor improvement in density, which was due to the assumptions and driving behavior parameters utilized to model driving behavior for different vehicle classes.
en
openAccess
Copyright held by the author.
Civil engineering
Transportation
Breaking points
Capacity adjustment factors
Connected and Autonomous Vehicles
Density
Freeway merge segment
Highway Capacity Manual
Estimating the Effect of Connected and Autonomous vehicles (CAVs) on Capacity and Level of Service at Freeway Merge Segments
Thesis
oai:kuscholarworks.ku.edu:1808/193772018-01-31T20:07:54Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Gevargizian, Jason
2016-01-01T21:11:45Z
2016-01-01T21:11:45Z
2015-05-31
http://dissertations.umi.com/ku:13872
http://hdl.handle.net/1808/19377
Program slicing is a popular program decomposition and analysis technique that extracts only those program statements that are relevant to particular points of interest. Executable slices are program slices that are independently executable and that correctly compute the values in the slicing criteria. Executable slices can be used during debugging and to improve program performance through paral- lelization of partially overlapping slices. While program slicing and the construction of executable slicers has been stud- ied in the past, there are few acceptable executable slicers available, even for pop- ular languages such as Java. In this work, we provide an extension to the T. J. Watson Libraries for Analysis (WALA), an open-source Java application static analysis suite, to generate fully executable slices. We analyze the problem of executable slice generation in the context of the capabilities provided and algorithms used by the WALA library. We then employ this understanding to augment the existing WALA static SSA slicer to efficiently track non-SSA data dependence, and couple this component with our executable slicer backend. We evaluate our slicer extension and find that it produces accurate executable slices for all programs that fall within the limitations of the WALA SSA slicer itself. Our extension to generate executable program slices facilitates one of the requirements of our larger project for a Java application automatic partitioner and parallelizer.
en
openAccess
Copyright held by the author.
Computer science
dependence
executable
partitioning
slice
slicers
slicing
Executables from Program Slices for Java Programs
Thesis
oai:kuscholarworks.ku.edu:1808/19732020-07-14T15:44:03Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Panzer, Ben
2008-03-01T15:11:25Z
2008-03-01T15:11:25Z
2007-12-12
http://dissertations.umi.com/ku:2283
http://hdl.handle.net/1808/1973
Radar operation from the CReSIS Meridian UAV requires a broadband antenna array composed of lightweight, thin, end-fire antenna elements. Toward this goal four Vivaldi antenna designs were simulated, fabricated, and characterized. The final design, dubbed the CReSIS Aerial Vivaldi - Revision A (CAV-A) provides operation over a band extending from 162 MHz to 1.121 GHz. The CAV-A measures 40 cm long, 51 cm wide, and 0.125 inch thick with a weight of 3.22 lbs., thus satisfying the requirements for UAV operation. Due to size, weight, and bandwidth requirements, a simple frequency scaling of a previously published design was unachievable. Most published single-element Vivaldi antenna designs were constrained by traditional thought that says the antenna length should be multiple free-space wavelengths and the antenna width should be a half free-space wavelength, both at the lowest frequency of interest. Contrary to convention, the CAV-A is an electrically small antenna, with an antenna width and length on the order of a quarter free-space wavelength at the lowest frequency of operation.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Electronics and electrical engineering
Vivaldi antenna
Electrically small
Ultra wide-band
Airborne antenna
Development of an Electrically Small Vivaldi Antenna: The CReSIS Aerial Vivaldi (CAV-A)
Thesis
oai:kuscholarworks.ku.edu:1808/83762020-08-20T12:42:23Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Kosuru, Lakshmi Anusha
2011-11-13T01:17:08Z
2011-11-13T01:17:08Z
2011-09-08
http://dissertations.umi.com/ku:11788
http://hdl.handle.net/1808/8376
Ultra High Frequency Radio Frequency Identification (UHF RFID) technology has gained prominence in recent years. It is being deployed extensively in supply chain and asset tracking by retailers to better control their inventory. The main drawback of UHF RFID tag antenna is that it is sensitive to the environment in which it operates. The performance of the tag degrades when placed on conductive or dielectric objects. While RFID tags near metal have been extensively evaluated in the literature, tags on and in dielectric media have received less scrutiny and rigorous evaluation. In this thesis, we develop a rigorous theoretical model for the behavior of RFID tags immersed in a dielectric medium using the Uda model and embedded T-match antenna. From this, we are able to investigate a number of criteria for optimality. We find that the simplest optimality condition is not physically realizable, and more realizable models yield several results that are of practical interest. Also, we propose a method to determine the input impedance of a center-fed dipole using a five element equivalent circuit. We relax the conditions for optimality and do an exhaustive search for the optimal design over the parametric space. Finally, we validate the model and present the trade-off to be made with the power transfer efficiency to obtain a tag working in wider range of dielectric materials. We make two specific recommendations for future work to increase the accuracy and usefulness of this work.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Electrical engineering
Antenna design
Dielectric materials
Embedded t-match
Uda model
Uhf rfid
Optimum Performance of UHF RFID Tags in Dielectric Environment
Thesis
oai:kuscholarworks.ku.edu:1808/183532020-06-24T18:28:54Zcom_1808_231com_1808_1260col_1808_18153col_1808_7158
Ward, Walter
2015-08-19T21:03:10Z
2015-08-19T21:03:10Z
1921
http://hdl.handle.net/1808/18353
openAccess
This work is in the public domain according to U.S. copyright law and is available for users to copy, use, and redistribute in part or in whole. No known restrictions apply to the work.
Flume construction on King Hill irrigation project
Thesis
oai:kuscholarworks.ku.edu:1808/194202018-12-17T16:42:23Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Mucci, Nicolas J.
2016-01-01T22:26:45Z
2016-01-01T22:26:45Z
2015-05-31
http://dissertations.umi.com/ku:14092
http://hdl.handle.net/1808/19420
The adsorption and aggregation of an intrinsically disordered soluble protein, tau, into insoluble filaments is a defining hallmark of many neurodegenerative diseases, commonly referred to as tauopathies. In its native state, the protein tau’s function is to promote the assembly, and aid in the stabilization of microtubules. The microtubules allow for material transport through the axon, to and from the neuron. While the presence of aggregated tau protein fibrils are hypothesized to accelerate neuronal degradation, possibly by destabilizing microtubules, or disrupting cell membranes, more recent research has established the presence of soluble oligomeric species as being cytotoxic. These results necessitate a complete fundamental understanding of the governing principles that modulate the initial steps in the mechanisms of tau protein aggregation. The macromolecular environment, including the presence of surfaces such as the cell membrane, and the presence of macromolecules in a crowded environment, has been implicated in the aggregation of tau protein. However, the exact role of surfaces in modulating Tau protein aggregation has not been explored in detail. We hypothesize that Tau protein aggregation at model surfaces is modulated by two factors, the physicochemical properties of the surfaces, as well as the biochemistry of the protein molecules. The work presented in this thesis project employs a combination of biophysical techniques to study the adsorption and aggregation of a wild type and several mutations of tau protein at model surfaces. A Quartz Crystal Microbalance with Dissipation (QCM-D) was used to monitor the adsorption of different tau species at nanomolar concentrations, mimicking the in vivo situation, to surfaces with different surface charge, wettability and softness, while Atomic Force Microscopy (AFM) was utilized to obtain direct visualization of the proteins at these different surfaces. Our results indicate that the hydrophobic amino acid sequence in the microtubule binding region was the leading force driving the adsorption of tau proteins to different surfaces. Further, AFM images provided direct evidence of the presence of oligomeric tau species at the interfaces, establishing that the solid surface did in fact provide a template for the tau protein to form aggregates. Adsorption of different tau protein mutations to phospholipid covered surfaces of different fluidity indicated that tau protein oligomers can also cause destabilization or disintegration of lipid bilayers. Such disintegration may well be the cause of observed cell death in several tauopathies. In summary, this thesis establishes that both protein biochemistry and the physicochemical properties of the surface modulate surface mediated aggregation. The work described in this thesis also provides a foundation for further research focused on the role of surfaces as templates that mediate tau aggregation pathway in vivo. A complete understanding of the mechanisms of tau aggregation will ultimately lead to strategies for therapeutic solutions for neurodegenerative diseases.
en
openAccess
Copyright held by the author.
Chemical engineering
Molecular biology
Adsorption
Aggregation
Alzheimer's
Neurodegeneration
Tau
Mechanisms of Adsorption and Surface-Mediated Aggregation of Intrinsically Disordered Protein Tau at Model Surfaces
Thesis
oai:kuscholarworks.ku.edu:1808/97812020-07-14T12:47:25Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Jowkar, Milad
2012-06-03T15:26:26Z
2012-06-03T15:26:26Z
2011-12-31
http://dissertations.umi.com/ku:11910
http://hdl.handle.net/1808/9781
Railroad ballast consists of open graded crushed stone used as a bed for railroad track to provide stability. It plays a significant role in providing support for the track base and distributing the load to the weaker subgrade below. Ballast also helps with drainage, which is an important factor for any type of transportation structure, including railroads. This issue has become more acute as heavier car loads place more demand on track structure than before. Over time ballast degrades and loses its strength. Fouling of ballast with fines has been a major issue of railway engineering. Fouling could be caused by break down of ballast itself or intrusion of fines from below or from the environment.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Civil engineering
Performance of Geogrid Reinforced Ballast under Dynamic Loading
Thesis
oai:kuscholarworks.ku.edu:1808/80562020-08-14T14:31:42Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Devarajan, Keerthana
2011-09-22T01:39:04Z
2011-09-22T01:39:04Z
2011-07-28
http://dissertations.umi.com/ku:11665
http://hdl.handle.net/1808/8056
Hearing is one of our main sensory systems and having a hearing disorder, although not life threatening, can have a disturbing impact in an individual's quality of life. Approximately 49 million Americans suffer from some form of hearing loss. Sensory neural hearing loss (SNHL) is the most common form, which results from degeneration of inner ear sensory hair cells and auditory neurons in the cochlea. In recent years, there has been an increasing interest in gene delivery to mesenchymal stem cells. Gene delivery approaches to stem cells can provide an opportunity to engineer a variety of specialized cell types. The objective of this thesis was to evaluate the potential of human umbilical cord mesenchymal stromal cells (hUCMSCs) as a possible source for regenerating inner ear hair cells. This thesis was successful in developing an adenoviral mediated gene delivery approach to deliver the Math1 gene to hUCMSCs. The expression of Math1 induced the differentiation of hUCMSCs into cells that resembled inner ear hair cells morphologically and immunocytochemically, evidenced by the expression of hair cell-specific and glial cell markers. The results obtained in this thesis demonstrated for the first time that hUCMSCs can differentiate into hair cell-like cells, thus introducing a potential tissue engineering and cell transplantation approach for the treatment of hearing loss.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Biomedical engineering
Bioengineering
Biomaterials
Tissue engineering
Adenoviral Mediated Gene Delivery to Human Umbilical Cord Mesenchymal Stromal Cells for Inner Ear Hair Cell Differentiation
Thesis
oai:kuscholarworks.ku.edu:1808/296612019-11-05T23:51:42Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Kakarapalli, Venkata Sai Raghu Teja
2019-10-28T22:59:03Z
2019-10-28T22:59:03Z
2018-05-31
http://dissertations.umi.com/ku:16344
http://hdl.handle.net/1808/29661
Construction is a dynamic process in which the outcomes depend on the quality of the project team; therefore, awarding the project to the best-suited contractor an important decision for owners. One method of contractor procurement is the best-value (BV) approach. When using this approach, the owner considers contractors’ qualifications in addition to their proposed prices; in contrast, price is the sole criterion in traditional low-bid procurement. BV has been used extensively by owners in the past few decades, with the goal of selecting the best-suited contractor for a specific project. But little research has been conducted that justifies the use of BV procurement within the Design-Bid-Build (DBB) system. This study aimed to fill the gap in the literature by statistically identifying whether BV procurement leads to owner’s benefits. Data were collected from 118 construction projects that were BV procured and D-B-B delivered. The data included the information such as the contractors’ price proposals and qualifications (as assessed through technical proposals, interviews, and past performance). The data also included performance indicators such as owner satisfaction scores and cost and schedule overruns. All the projects selected for this study were public vertical projects; most were renovation projects. The data were analyzed through using descriptive statistics and inferential statistics. The results indicate that employing a BV-procured contractor can be beneficial to owners in terms of cost and schedule performance. The findings also indicate that groups of contractors that receive high scores for technical proposals and interviews also achieve better project performance. Because BV involves potentially selecting an expensive contractor compared to the lowest bidder, an attempt was made to measure the cost of the selected contractor. To measure the cost, the concept of total BV cost was developed. The results indicate that BV-selected contractors have lower overall costs than do average bidders.
en
openAccess
Copyright held by the author.
Civil engineering
Best-Value
Design-Bid-Build
Project Performance
Renovation Construction
Vertical Construction
Linking Best-Value Procurement with Project Performance Outcomes in Design-Bid-Build Vertical Construction Projects
Thesis
oai:kuscholarworks.ku.edu:1808/44412020-07-22T14:51:26Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Eslick, John
2009-03-24
2009-03-24
2009-01-01
http://dissertations.umi.com/ku:10163
http://hdl.handle.net/1808/4441
https://orcid.org/0000-0002-7334-2277
A complete methodology for the computational molecular design (CMD) of crosslinked polymers is developed and implemented. The methodology is applied to the design of novel polymers for restorative dental materials. The computational molecular design of crosslinked polymers using optimization techniques is a new area of research. The first part of this project seeks to develop a novel data structure capable of adequately storing a complete description of the crosslinked polymer structure. Numerical descriptors of polymer structure are then calculated from the data structure. Statistical methods are used to relate the structural descriptors to experimentally measured properties. An important part of this project is to show that useful property prediction models can be developed for crosslinked polymers. Desirable property target values are then set for a specific application. Finally, the structure-property relations are combined with a Tabu search optimization algorithm to design improved polymers. Tabu search allows much flexibility in the problem formulations, so a major goal of this project is to show that Tabu search is a effective method for crosslinked polymer design. To implement the molecular design procedure, a software package is developed. The software allows for easy graphical entry of polymer structures and property data, and contains a Tabu search optimization routine. Since computational molecular design of crosslinked polymers is a relatively new area of research, the software is designed to be easily modified to allow for extensive numerical experimentation. Finally, the computational design methodology is demonstrated for the design of polymers for restorative dental applications. Using the computational molecular design methodology developed in this project, several monomers are found that may offer a significant improvement over a standard HEMA/bisGMA formulation. The results of the case study show that the new data structure for crosslinked polymers is effective for calculation of topological descriptors and roperty models can be developed for crosslinked polymers. Tabu search is also shown to be an effective optimization method.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Chemical engineering
Molecular Design of Crosslinked Copolymers
Dissertation
oai:kuscholarworks.ku.edu:1808/296292019-11-05T23:51:42Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Al-Ibadi, Mohanad
2019-10-15T16:31:28Z
2019-10-15T16:31:28Z
2019-05-31
http://dissertations.umi.com/ku:16582
http://hdl.handle.net/1808/29629
Ice bottom topography layers are an important boundary condition required to model the flow dynamics of an ice sheet. In this work, using low frequency multichannel radar data, we locate the ice bottom using two types of automatic trackers. First, we use the multiple signal classification (MUSIC) beamformer to determine the pseudo-spectrum of the targets at each range-bin. The result is passed into a sequential tree-reweighted message passing belief-propagation algorithm to track the bottom of the ice in the 3D image. This technique is successfully applied to process data collected over the Canadian Arctic Archipelago ice caps in 2014, and produce digital elevation models (DEMs) for 102 data frames. We perform crossover analysis to self-assess the generated DEMs, where flight paths cross over each other and two measurements are made at the same location. Also, the tracked results are compared before and after manual corrections. We found that there is a good match between the overlapping DEMs, where the mean error of the crossover DEMs is 38±7 m, which is small relative to the average ice-thickness, while the average absolute mean error of the automatically tracked ice-bottom, relative to the manually corrected ice-bottom, is 10 range-bins. Second, a direction of arrival (DOA)-based tracker is used to estimate the DOA of the backscatter signals sequentially from range bin to range bin using two methods: a sequential maximum a posterior probability (S-MAP) estimator and one based on the particle filter (PF). A dynamic flat earth transition model is used to model the flow of information between range bins. A simulation study is performed to evaluate the performance of these two DOA trackers. The results show that the PF-based tracker can handle low-quality data better than S-MAP, but, unlike S-MAP, it saturates quickly with increasing numbers of snapshots. Also, S-MAP is successfully applied to track the ice-bottom of several data frames collected from over Russell glacier in 2011, and the results are compared against those generated by the beamformer-based tracker. The results of the DOA-based techniques are the final tracked surfaces, so there is no need for an additional tracking stage as there is with the beamformer technique.
en
openAccess
Copyright held by the author.
Electrical engineering
Direction of arrival estimation
Model order estimation
Radar imaging
Sequential tracking
Synthetic aperture radar
ARRAY PROCESSING TECHNIQUES FOR ESTIMATION AND TRACKING OF AN ICE-SHEET BOTTOM
Dissertation
oai:kuscholarworks.ku.edu:1808/43662020-07-22T14:38:24Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Johnson, Joshua E.
2009-02-02T06:47:21Z
2009-02-02T06:47:21Z
2008-01-01
http://dissertations.umi.com/ku:10124
http://hdl.handle.net/1808/4366
Due to the severity and continuing escalation in occurrences of degenerative joint diseases, it is vital to establish a means of detection and prevention that could lead to an improvement in quality of life. One such means is MRI-based modeling for joint contact analysis of in vivo functional loading. The purpose of this study was to validate models generated from a clinical MR scanner for future in vivo joint contact analyses. Models were tested using 3 cadaver forearm specimens and compared with experimental data. It was found that models were validated based on contact area. Direct contact area measurements were observed to be very close to experimental data. Model force measurements were reasonable, but did not agree with experimental data as well as contact area. Peak pressure data from the models were less consistent in correspondence with experimental data. Also, radiocarpal mechanics were investigated to determine the effect of inserting a sensor into the joint space. Magnitudes of bone motions were found to be greater with film inserted than without film. Model results showed contact areas to be higher with film than without film.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Mechanical engineering
Validation of Radiocarpal Joint Contact Models Based On Images from a Clinical MRI Scanner
Thesis
oai:kuscholarworks.ku.edu:1808/98092020-07-13T16:09:05Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Higgins, Thomas
2012-06-03T16:20:21Z
2012-06-03T16:20:21Z
2011-12-31
http://dissertations.umi.com/ku:11857
http://hdl.handle.net/1808/9809
Waveform diversity may offer several benefits to radar systems though often at the cost of reduced sensitivity. Multi-dimensional processing schemes are known to offer many degrees of freedom, which can be exploited to suppress the ambiguity inherent to pulse compression, array processing, and Doppler frequency estimation. Spatial waveform diversity can be achieved by transmitting different but correlated waveforms from each element of an antenna array. A simple yet effective scheme is employed to transmit different waveforms in different spatial directions. A new reiterative minimum mean squared error approach entitled Space-Range Adaptive Processing, which adapts simultaneously in range and angle, is derived and shown in simulation to offer enhanced performance when spatial waveform diversity is employed relative to both conventional matched filtering and sequentially adapting in angle and then range. The same mathematical framework is utilized to develop Time-Range Adaptive Processing (TRAP) algorithm which is capable of simultaneously adapting in Doppler frequency and range. TRAP is useful when pulse-to-pulse changing of the center frequency or waveform coding is used to achieve enhanced range resolution or unambiguous ranging, respectively. The inherent computational complexity of the new multi-dimensional algorithms is addressed by segmenting the full-dimension cost functions, yielding a reduced-dimensional variants of each. Finally, a non-adaptive approach based on the multi-dimensional TRAP signal model is utilized to develop an efficient clutter cancellation technique capable of suppressing multiple range intervals of clutter when waveform diversity is applied to pulse-Doppler radar.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Electrical engineering
Waveform Diversity and Range-Coupled Adaptive Radar Signal Processing
Dissertation
oai:kuscholarworks.ku.edu:1808/151282020-10-01T14:49:56Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Butts, Chelsey Elizabeth
2014-09-25T03:36:54Z
2014-09-25T03:36:54Z
2013-05-31
http://dissertations.umi.com/ku:12943
http://hdl.handle.net/1808/15128
The purpose of this study was to determine how AmeriCorps State and National volunteers in school settings think the experience has influenced them, their goals, and future plans. I used semi structure interviews to investigate this question. Members I interviewed talked about the first-hand teaching experience they receive through volunteering, teamwork, networking within the school system, personal growth, and an increased willingness to serve their communities. The discussion of these elements suggests their importance to volunteers, future employers, university education programs, and service program directors.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Education
Americorps
Public schools
Volunteer
QUALITATIVE INQUIRY INTO FULL-TIME AMERICORPS STATE AND NATIONAL VOLUNTEERS IN ELEMENTARY SCHOOLS
Thesis
oai:kuscholarworks.ku.edu:1808/39562018-01-31T20:08:15Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Bundy, Brandon
2008-07-14T23:18:52Z
2008-07-14T23:18:52Z
2008-04-30
http://dissertations.umi.com/ku:2518
http://hdl.handle.net/1808/3956
Pedestrian countdown timers (CDTs) are promoted as a means of improving pedestrian safety at intersections. However, there are concerns that drivers view the CDTs when approaching the intersection and use that information to drive more aggressively - an unintended consequence that is detrimental to safety. Pedestrian CDTs have been in use in Lawrence, Kansas for at least three years, and so any novelty effect should have passed, allowing for an accurate analysis of the long-term effects of the devices on traffic. Four intersections along an arterial corridor in Lawrence were studied - two with CDTs and two with flashing hand pedestrian signal heads. Continuous speed data were collected on approaching traffic and analyzed to determine if there were changes in speed between 400 ft upstream from the intersection (the point when the CDT information could be read by drivers) and the intersection stop bar. Additionally, the ultimate decision of the drivers (whether they stopped or not) was recorded. Analysis revealed that drivers were less likely to increase their approach speed when a CDT was present. Additionally, some drivers began to slow to a stop before the beginning of the amber phase when CDTs were present. These findings indicate that drivers use the information provided from pedestrian CDTs to improve their driving decisions. Even though the CDT information was not intended to be used by drivers, it appears that they are indeed doing so in a way that results in safer driving actions.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Civil engineering
Transportation
Pedestrian
Countdown timer
Cdt
Driver behavior
Driver modification
Modification of Driver Behavior Based on Information from Pedestrian Countdown Timers
Thesis
oai:kuscholarworks.ku.edu:1808/257722019-01-17T16:56:34Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Althnian, Alhanoof
2018-01-29T17:47:52Z
2018-01-29T17:47:52Z
2016-12-31
http://dissertations.umi.com/ku:14961
http://hdl.handle.net/1808/25772
Multi-agent systems are a common paradigm for building distributed systems in different domains such as networking, health care, swarm sensing, robotics, and transportation. Systems are usually designed or adjusted in order to reflect the performance trade-offs made according to the characteristics of the mission requirement. Research has acknowledged the crucial role that communication plays in solving many performance problems. Conversely, research efforts that address communication decisions are usually designed and evaluated with respect to a single predetermined performance goal. This work introduces Goal-Driven Communication, where communication in a multi-agent system is determined according to flexible performance goals. This work proposes an evolutionary approach that, given a performance goal, produces a communication strategy that can improve a multi-agent system's performance with respect to the desired goal. The evolved strategy determines what, when, and to whom the agents communicate. The proposed approach further enables tuning the trade-off between the performance goal and communication cost, to produce a strategy that achieves a good balance between the two objectives, according the system designer's needs.
en
openAccess
Copyright held by the author.
Computer science
Communication strategy
Evolutionary communication
Genetic Algorithm
Muti-agent Systems
Evolutionary Learning of Goal-Driven Multi-agent Communication
Dissertation
oai:kuscholarworks.ku.edu:1808/278152020-10-12T14:01:44Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Asadollahi, Parisa
2019-05-07T16:52:58Z
2019-05-07T16:52:58Z
2018-12-31
http://dissertations.umi.com/ku:16187
http://hdl.handle.net/1808/27815
https://orcid.org/0000-0002-0805-3962
Long-span bridges are important components of civil infrastructure systems because they are vital links in transportation systems. Therefore, as bridge systems age, understanding the safety and serviceability performance of structural components of these systems through structural health monitoring (SHM) techniques is necessary to achieve economically sustainable maintenance. Application of Bayesian inference in SHM techniques provides a reliable platform to deal with different sources of uncertainty in the process and also to obtain probabilistic results which are more meaningful for decision-making. This research seeks to address some of the key challenges in SHM of large-scale civil infrastructures such as analyzing a huge quantity of measured data for system identification, dealing with uncertainty in measurements and analytical models of structures, performing a real-world application of Bayesian Finite Element (FE) model updating, and Bayesian-based damage detection. The proposed research focuses on the following tasks: 1) development of an autonomous data pre-processing and system identification to analyze a large amount of response measurements, and extraction of statistical features of dynamic properties of a large-scale cable-stayed bridge, 2) recommendation of an effective way to systematically deal with different sources of uncertainty in Bayesian FE model updating, and implementation of a real-world application of Bayesian FE model updating on a large-scale bridge to achieve a more accurate FE model for response predictions, and finally 3) proposing a new Bayesian-based structural damage identification technique applicable for bridge structures based on the measurements of their healthy and unhealthy states.
en
openAccess
Copyright held by the author.
Engineering
Bayesian Finite Element Model Updating
Cable-stayed Bridges
Sparse Bayesian Learning
Structural Damage Detection
Structural Health Monitoring
System identification
Bayesian-based Finite Element Model Updating, Damage Detection, and Uncertainty Quantification for Cable-stayed Bridges
Dissertation
oai:kuscholarworks.ku.edu:1808/81602020-06-25T19:14:06Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Morozov, Serhiy
2011-10-09T03:54:21Z
2011-10-09T03:54:21Z
2011-08-31
http://dissertations.umi.com/ku:11692
http://hdl.handle.net/1808/8160
10.1146/annurev.ecolsys.28.1.289
The use of recommender systems is an emerging trend today, when user behavior information is abundant. There are many large datasets available for analysis because many businesses are interested in future user opinions. Sophisticated algorithms that predict such opinions can simplify decision-making, improve customer satisfaction, and increase sales. However, modern datasets contain millions of records, which represent only a small fraction of all possible data. Furthermore, much of the information in such sparse datasets may be considered irrelevant for making individual recommendations. As a result, there is a demand for a way to make personalized suggestions from large amounts of noisy data. Current recommender systems are usually all-in-one applications that provide one type of recommendation. Their inflexible architectures prevent detailed examination of recommendation accuracy and its causes. We introduce a novel architecture model that supports scalable, distributed suggestions from multiple independent nodes. Our model consists of two components, the input matrix generation algorithm and multiple platform-independent combination algorithms. A dedicated input generation component provides the necessary data for combination algorithms, reduces their size, and eliminates redundant data processing. Likewise, simple combination algorithms can produce recommendations from the same input, so we can more easily distinguish between the benefits of a particular combination algorithm and the quality of the data it receives. Such flexible architecture is more conducive for a comprehensive examination of our system. We believe that a user's future opinion may be inferred from a small amount of data, provided that this data is most relevant. We propose a novel algorithm that generates a more optimal recommender input. Unlike existing approaches, our method sorts the relevant data twice. Doing this is slower, but the quality of the resulting input is considerably better. Furthermore, the modular nature of our approach may improve its performance, especially in the cloud computing context. We implement and validate our proposed model via mathematical modeling, by appealing to statistical theories, and through extensive experiments, data analysis, and empirical studies. Our empirical study examines the effectiveness of accuracy improvement techniques for collaborative filtering recommender systems. We evaluate our proposed architecture model on the Netflix dataset, a popular (over 130,000 solutions), large (over 100,000,000 records), and extremely sparse (1.1\%) collection of movie ratings. The results show that combination algorithm tuning has little effect on recommendation accuracy. However, all algorithms produce better results when supplied with a more relevant input. Our input generation algorithm is the reason for a considerable accuracy improvement.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Computer science
A Distributed, Architecture-Centric Approach to Computing Accurate Recommendations from Very Large and Sparse Datasets
Dissertation
oai:kuscholarworks.ku.edu:1808/97692020-07-14T13:24:24Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Peck, Wesley Graham
2012-06-03T15:12:21Z
2012-06-03T15:12:21Z
2011-12-31
http://dissertations.umi.com/ku:11919
http://hdl.handle.net/1808/9769
System-level design is an engineering discipline focused on producing methods, technologies, and tools that enable the specification, design, and implementation of complex, multi-discipline, and multi-domain systems. System-level specifications are as abstract as possible, defining required system behaviors while eliding implementation details. These implementation details must be added during the implementation process and the high effort associated with this locks system engineers onto the chosen implementation architecture. This work provides two contributions that ease the implementation process. The Rosetta synthesis capability generates hardware/software co-designed implementations from specifications that contain low level implementation details. The Rosetta refinement capability extends this by allowing a system's functional behavior and its implementation details to be described separately. The Rosetta Refinement Tool combines the functional behavior and the implementation details to form a system specification that can be synthesized using the Rosetta synthesis capability. The Rosetta refinement capability is exposed using existing Rosetta language constructs that have, previous to this work, never been exploited. Together these two capabilities allow the refinement of high level, architecture independent specifications into low level, architecture specific hardware/software co-designed implementations. The result is an effective platform for rapid prototyping of hardware/software co-designs and provides system engineers with the novel ability to explore different system architectures with low effort.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Computer science
Computer engineering
Co-design
Hardware
Refinement
Software
Specification
Hardware/Software Co-Design via Specification Refinement
Dissertation
oai:kuscholarworks.ku.edu:1808/129912020-10-21T15:27:53Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Renth, Amanda
2014-02-05T16:51:22Z
2014-02-05T16:51:22Z
2013-12-31
http://dissertations.umi.com/ku:13135
http://hdl.handle.net/1808/12991
Cartilage defects, whether caused by osteoarthritis, joint trauma, or other disease, have provoked a wide variety of tissue engineering scaffold strategies in recent years. Traditionally, cartilage tissue engineering scaffolds have utilized synthetic polymer components to form hydrogels or other porous matrices. However, components found within the extracellular matrix (ECM) such as collagen, glycosaminoglycans (GAGs), and ECM-based matrices have emerged as an essential subset of biomaterials for tissue engineering scaffolds. The objective of this research was to develop and evaluate decellularized cartilage (DCC) as a chondroinductive material for cartilage tissue engineering applications. This work was successful in developing a decellularization method for hyaline cartilage fragments that removed 99% of cells, while retaining 87% of GAGs and also in determining a method to produce a homogenous nanopowder of DCC. Additionally, this research was the first to examine the ability of DCC to induce chondrogenesis in stem cells by quantifying gene expression of chondrogenic markers. The results demonstrate for the first time that DCC can indeed upregulate chondrogenic markers and may be a new chondroinductive material that can provide microenvironmental cues and signaling to promote stem cell differentiation in cartilage regeneration.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Biomedical engineering
Cartilage tissue engineering
Decellularized cartilage
Raw materials
Decellularized cartilage as a chondroinductive material for cartilage tissue engineering
Thesis
oai:kuscholarworks.ku.edu:1808/297102020-10-07T21:20:41Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Sajid, Usman
2019-11-01T01:15:32Z
2019-11-01T01:15:32Z
2019-05-31
http://dissertations.umi.com/ku:16563
http://hdl.handle.net/1808/29710
https://orcid.org/0000-0002-2443-5215
As people gather during different social, political or musical events, automated crowd analysis can lead to effective and better management of such events to prevent any unwanted scene as well as avoid political manipulation of crowd numbers. Crowd counting remains an integral part of crowd analysis and also an active research area in the field of computer vision. Existing methods fail to perform where crowd density is either too high or too low in an image, thus resulting in either overestimation or underestimation. These methods also mix crowd-like cluttered background regions (e.g. tree leaves or small and continuous patterns) in images with actual crowd, resulting in further crowd overestimation. In this work, we present a novel deep convolutional neural network (CNN) based framework ZiZoNet for automated crowd counting in static images in very low to very high crowd density scenarios to address above issues. ZiZoNet consists of three modules namely Crowd Density Classifier (CDC), Decision Module (DM) and Count Regressor Module (CRM). The test image, divided into 224x224 patches, passes through the CDC module that classifies each patch to a class label (no-crowd, low-crowd, medium-crowd, high-crowd). Based on the CDC information and using either heuristic Rule-set Engine (RSE) or machine learning based Random Forest based Decision Block (RFDB), DM decides which mode (zoom-in, normal or zoom-out) this image should use for crowd counting. CRM then performs patch-wise crowd estimate for this image accordingly as decided or instructed by the DM module. Extensive experiments on three diverse and challenging crowd counting benchmarks (UCF-QNRF, ShanghaiTech, AHU-Crowd) show that our method outperforms current state-of-the-art models under most of the evaluation criteria.
en
openAccess
Copyright held by the author.
Computer science
deep learning
densenet
machine learning
ZiZoNet: A Zoom-In and Zoom-Out Mechanism for Crowd Counting in Static Images
Thesis
oai:kuscholarworks.ku.edu:1808/236572017-12-08T21:43:43Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
O'Mara, George E.
2017-04-13T15:15:59Z
2017-04-13T15:15:59Z
1931
http://hdl.handle.net/1808/23657
openAccess
This work is in the public domain and is available for users to copy, use, and redistribute in part or in whole. No known restrictions apply to the work.
Standardization tests of the Kansas University wind tunnel
Thesis
oai:kuscholarworks.ku.edu:1808/259362018-02-07T23:13:41Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Diederich, Simon
2018-02-07T05:11:26Z
2018-02-07T05:11:26Z
2017-12-31
http://dissertations.umi.com/ku:15706
http://hdl.handle.net/1808/25936
The goal of this project was to design, construct and commission a calorimeter for testing the thermal properties of state-of-the-art luminaires. The calorimeter was built to serve as a testing facility in the Lighting Research Laboratory at the University of Kansas School of Engineering. The calorimeter was designed to approximate a room to achieve testing results that could be applicable in the actual applications. The calorimeter is a highly insulated box (1990 mm x 740 mm x 1915 mm) equipped with six temperature sensors to measure temperature at the air intakes, exhausts and in the center of the calorimeter and two anemometers to measure the air flow rate running through the ceiling cavity and room cavity. Luminaires will be installed in the calorimeter for testing their thermal performance. With a two-cavity-layout and a material of choice separating the two cavities, the calorimeter allows for the one-dimensional analysis of heat distribution. Using data from the temperature sensors and the air flow rate, the heat released by the luminaires to the ceiling cavity and the room cavity can be calculated respectively. Due to its mobility, the calorimeter can be used in different environments such as a temperature-controlled room. Later in a commissioning process, the calorimeter’s accuracy was tested using a controllable heat source. A cartridge heater with an adjustable heat output was used to compare to the heat measured by the calorimeter. The results show that the calorimeter has an error of 11% for testing the cartridge heater which approximates equivalent 50W of comparable luminaires. The error decreases with increased cartridge heater wattages. Results for a 114 W energy input show an error of less than 1%.
en
openAccess
Copyright held by the author.
Engineering
Development and Commissioning of a Calorimeter for Testing the Thermal Performance of Luminaires
Thesis
oai:kuscholarworks.ku.edu:1808/114552020-09-25T13:45:42Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Hurt, Mark Anthony
2013-07-14T15:20:31Z
2013-07-14T15:20:31Z
2013-05-31
http://dissertations.umi.com/ku:12616
http://hdl.handle.net/1808/11455
The Kansas Department of Transportation is currently facing the contradictory requirements of providing equivalent or improved operations to facilitate economic growth and reductions in funding. This will require the agency to maintain and operate its existing infrastructure as efficiently as possible. This is particularly true in regard to its inventory of bridges. This project examines KDOT's practices for substantial maintenance of bridges in its inventory and, specifically, the work of the Bridge Maintenance Plans (BMP) squad. The efficiency and effectiveness of the delivery of plans and of engineering support by the BMP squad is reviewed by an analysis of Preliminary Engineering and Construction Engineering costs for substantial maintenance during the period of FY 1993 to FY 2010. The practices of surrounding states are discussed. The cost of current maintenance practices as opposed to more minimal investment in substantial maintenance for bridges is examined by review of the projects in the FY 2003 Bridge Substantial Maintenance program. The findings for agency cost as determined by Bridge Life Cycle Cost analysis are discussed. The findings for user cost as determined by an analysis of user delay at work zones and closures are discussed. The economic impact of allowing bridges at one site in the FY 2003 to deteriorate to restricted status for two years is reviewed.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Civil engineering
Bridge
Substantial maintenance
Substantial Maintenance Practices for Bridges on the Kansas State Highway System
Dissertation
oai:kuscholarworks.ku.edu:1808/275962020-10-13T20:38:08Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
McCormick, Patrick Michael
2019-01-01T21:13:57Z
2019-01-01T21:13:57Z
2018-05-31
http://dissertations.umi.com/ku:15992
http://hdl.handle.net/1808/27596
https://orcid.org/0000-0003-2332-4000
With the advancement of arbitrary waveform generation techniques, new radar transmission modes can be designed via precise control of the waveform's time-domain signal structure. The finer degree of emission control for a waveform (or multiple waveforms via a digital array) presents an opportunity to reduce ambiguities in the estimation of parameters within the radar backscatter. While this freedom opens the door to new emission capabilities, one must still consider the practical attributes for radar waveform design. Constraints such as constant amplitude (to maintain sufficient power efficiency) and continuous phase (for spectral containment) are still considered prerequisites for high-powered radar waveforms. These criteria are also applicable to the design of multiple waveforms emitted from an antenna array in a multiple-input multiple-output (MIMO) mode. In this work, three spatially-diverse radar emission design methods are introduced that provide constant amplitude, spectrally-contained waveforms implemented via a digital array radar (DAR). The first design method, denoted as spatial modulation, designs the radar waveforms via a polyphase-coded frequency-modulated (PCFM) framework to steer the coherent mainbeam of the emission within a pulse. The second design method is an iterative scheme to generate waveforms that achieve a desired wideband and/or widebeam radar emission. However, a wideband and widebeam emission can place a portion of the emitted energy into what is known as the `invisible' space of the array, which is related to the storage of reactive power that can damage a radar transmitter. The proposed design method purposefully avoids this space and a quantity denoted as the Fractional Reactive Power (FRP) is defined to assess the quality of the result. The third design method produces simultaneous radar and communications beams in separate spatial directions while maintaining constant modulus by leveraging the orthogonal complement of the emitted directions. This orthogonal energy defines a trade-space between power efficiency gained from constraining waveforms to be constant amplitude and power efficiency lost by emitting energy in undesired directions. The design of FM waveforms via traditional gradient-based optimization methods is also considered. A waveform model is proposed that is a generalization of the PCFM implementation, denoted as coded-FM (CFM), which defines the phase of the waveform via a summation of weighted, predefined basis functions. Therefore, gradient-based methods can be used to minimize a given cost function with respect to a finite set of optimizable parameters. A generalized integrated sidelobe level (GISL) metric is used as the optimization cost function to minimize the correlation range sidelobes of the radar waveform. System specific waveform optimization is explored by incorporating the linear models of three different loopback configurations into the GISL metric to match the optimized waveforms to the particular systems.
en
openAccess
Copyright held by the author.
Electrical engineering
Hardware modeling
MIMO
Optimization
Radar
RF
Waveform
Design and Optimization of Physical Waveform-Diverse and Spatially-Diverse Radar Emissions
Dissertation
oai:kuscholarworks.ku.edu:1808/194272018-01-31T20:07:54Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Collins, Patrick Gordon
2016-01-01T22:36:41Z
2016-01-01T22:36:41Z
2015-05-31
http://dissertations.umi.com/ku:13927
http://hdl.handle.net/1808/19427
Due to more stringent emissions and fuel economy standards, many automotive manufacturers are implementing more electric and hybrid vehicles into their model fleets. Hybrid and purely electric powertrains offer more sustainable transportation methods; however, larger sport utility vehicles and trucks occupy a significant majority of the vehicles on the road in the United States. To this end, this work covers the development of a second generation electric sport utility vehicle at the University of Kansas. Chapter 2 of this thesis outlines the use of CAN bus in the automotive industry throughout the evolution of the Electronic Control Module. Chapter 2 also showcases the different types of control modules installed in vehicles. CAN bus theory of operation, message formats, error handling, wiring techniques, and additional vehicle networking methods are also discussed. Lastly, electric vehicle case studies at the University of Kansas are presented to illustrate the importance and benefits of implementing CAN bus. Chapter 3 focuses on the development of the JimmE-V. The JimmE-V serves as a research vehicle that has features similar to EVs available to consumers. In order for the vehicle to generate research quality data, vehicle operation and systems integration are discussed. CAN bus communication allows components to be controlled, calibrated, and monitored in real-time allowing the JimmE-V to be adjusted for a variety of research studies. Safety information is also provided due to the high voltage potential when working with EVs. The different causes for vehicle failure are additionally included in this chapter. Chapter 4 examines the complete energy and emissions produced by the JimmE-V. This chapter highlights the energy used in the vehicle manufacturing process in addition to examining the benefit of reusing vehicle components. Furthermore, a Life-Cycle Analysis (LCA) was generated using Argonne National Laboratory’s Greenhouse Gasses, Regulated Emissions, and Energy Use in Transportation (GREET) model. The LCA provides estimations for the JimmE-V’s energy use and emissions produced throughout the vehicle’s lifetime use. Accompanying this information is information regarding the iv production and recycling of LiFePO4 batteries. This work’s LCA efforts for the JimmE-V are compared to the previous LCA efforts for the VW Beetle. Drive cycle data was collected to examine the efficiency of the JimmE-V, and to compare the results to the VW Beetle. Lastly, the solar generation capabilities of the newly built (2013) Hill Engineering Research and Development Center are presented. Lastly, Chapter 5 focuses on the conclusions of the JimmE-V project mainly highlighting the author’s main contributions to EV projects at the University of Kansas. The author’s main contributions were centered on the powertrain of the JimmE-V including the motor, controller, ECM, and battery pack. This chapter additionally focuses on the vehicle’s future impact as a research platform.
en
openAccess
Copyright held by the author.
Mechanical engineering
Automotive engineering
Electrical engineering
CAN
Electric Vehicle
EV
LCA
LiFePO4
SUV
Second Generation Electric Vehicle Development at the University of Kansas
Thesis
oai:kuscholarworks.ku.edu:1808/43672020-07-22T14:41:31Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Joarder, Arif
2009-02-02T06:50:14Z
2009-02-02T06:50:14Z
2008-01-01
http://dissertations.umi.com/ku:10130
http://hdl.handle.net/1808/4367
XML has gained worldwide popularity for its ability to represent very general structured content. It is a platform independent format that has been successfully used for both media and more traditional textual data. However, the presentation of XML content has been an area of research ever since its introduction. We discuss the state of the art in XML content presentation, and then describe a new method for user designed transformation using WYSIWYG templates in HTML, that will allow users to design their own XML presentation format.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Computer science
Html
Presentation
Transformation
XML
XSLT
Presentation of XML content using WYSIWYG templates
Thesis
oai:kuscholarworks.ku.edu:1808/85172020-08-27T14:27:29Zcom_1808_231com_1808_1260col_1808_18153col_1808_7158
Godfrey, Truman M.
2011-11-23T16:51:33Z
2011-11-23T16:51:33Z
1913-05-15
http://hdl.handle.net/1808/8517
en_US
openAccess
This work is in the public domain according to U.S. copyright law and is available for users to copy, use, and redistribute in part or in whole. No known restrictions apply to the work.
Conductivity as applied to water analysis
Thesis
oai:kuscholarworks.ku.edu:1808/43162020-07-22T12:50:28Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Wang, Limin
2009-01-12T05:50:08Z
2009-01-12T05:50:08Z
2008-09-09
http://dissertations2.umi.com/ku:2731
http://hdl.handle.net/1808/4316
The temporomandibular joint (TMJ), associated with everyday activities, such as chewing, yawning, talking, and laughing, is one of the most complex but least studied joints in the musculoskeletal system. Patients suffering from TMJ disorders (TMDs) may experience a variety of agonizing symptoms, such as earaches, headaches, neck pain, and difficulty opening the mouth, while current treatments are inefficacious owing to a poor understanding of TMJ disorder pathologies. Prior to this thesis, human umbilical cord mesenchymal stromal cells (hUCMSCs), identified as multipotent cells only in this decade, had not yet been used for TMJ tissue engineering. Hence, this thesis proposed a revolutionary tissue engineering approach in which hUCMSCs and mature hyaline cartilage cells, scaffolds, and growth factors were integrated to create TMJ condylar bone and cartilage in vitro to substitute for deteriorated native tissues. hUCMSCs were successfully differentiated along chondrogenic and osteogenic lineages in a 3D biomaterial-based environment, supporting the feasibility of using these cells for TMJ cartilage and bone tissue engineering. In TMJ cartilage regeneration, hUCMSCs demonstrated significant advantages over both mature TMJ cells and human bone marrow mesenchymal stromal cells (hBMSCs), with faster cell proliferation and superior biosynthesis. As an additional alternative, hyaline cartilage cells also surpassed TMJ cells in that they produced considerably more extracellular matrix. Following the initial efforts, the cell culture environment was refined, including cell seeding densities and signaling strategies. Higher cell seeding densities (25 million cells/ml) were recommended for both cartilage and bone tissue engineering, mainly due to their benefits to differentiation and biosynthesis. Insulin-like growth factor I (IGF-I) enhanced the chondrogenesis of pre-differentiated hUCMSCs while having no effect on osteogenically induced hUCMSCs. Therefore, the work on the successful differentiation of hUCMSCs in 3D biomaterials has been pioneering, and the culture parameters for in vitro TMJ tissue engineering have been refined. Moreover, this innovative work has tremendous implications for a broader area (e.g., musculoskeletal tissue engineering).
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Chemical engineering
Biomedical engineering
Tissue Engineering the TMJ Condyle using Human Umbilical Cord Mesenchymal Stromal Cells
Dissertation
oai:kuscholarworks.ku.edu:1808/41662020-07-20T15:09:34Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Pathak, Bogdan Amaru
2008-09-15T03:20:19Z
2008-09-15T03:20:19Z
2008-08-01
http://dissertations.umi.com/ku:2692
http://hdl.handle.net/1808/4166
A Langmuir probe diagnostic system was developed to measure the electron density distribution in BCl3/N2 mixtures to determine if an average electron energy increase might be partially responsible for the previously observed etch rate enhancement of GaAs with nitrogen addition. The system was validated in both helium and nitrogen plasmas. Probe measurements showed that as the nitrogen concentration in BCl3/N2 plasmas increased, the average electron energy actually decreased (5.52 eV @ 0% N2, 4.14 eV @ 30% N2, and 3.69 eV @ 60% N2). However, an increase in negative ion density was observed with nitrogen addition reaching a maximum at 40% N2. Although negative ions play no role in etching, this trend seems to correlate with the observed etch rate enhancement. A plausible explanation for both the increase in etch species and the increase in negative ion density is an increase in dissociation due to energy transfer from N2 metastables.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Electronics and electrical engineering
Physics
Fluid and plasma
Materials science engineering
Langmuir probe
Bcl3
N2
He
Plasma
Etching
ELECTROSTATIC (LANGMUIR) PROBE MEASUREMENTS IN RF DRIVEN He, N2, BCl3, AND BCl3/N2 PLASMAS
Thesis
oai:kuscholarworks.ku.edu:1808/102062018-01-31T20:08:15Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Ragone, J. Colter
2012-10-27T10:22:13Z
2012-10-27T10:22:13Z
2012-08-31
http://dissertations.umi.com/ku:12367
http://hdl.handle.net/1808/10206
Due to increasingly stringent regulations set forth by the Environmental Protection Agency, engine researchers and manufacturers are testing and developing various emission reduction strategies for compression ignition engines. This thesis contains three sections where the author details two separate strategies for emission reduction and assisted combustion. Combustion resulting from compression ignition diesel engines contains high levels of nitrogen oxides (NOx) due to their lean operating characteristics. A common NOx reduction strategy used by most automotive manufactures involves the use of cooled EGR (exhaust gas recirculation) to reduce combustion temperatures. However, a downfall to this method is the formation of particulate matter (PM) from the reduced combustion temperatures. This reduction in NOx emissions with resulting increasing PM emissions describes the well-known NOx-PM tradeoff. Typically, a reduction in one of the emissions will result in an increase in the other. Chapter two documents the construction and testing of a cooled EGR system for a single cylinder diesel engine along with subsequent performance and emission analysis. The result of the cooled EGR system demonstrates a reduction in brake specific NOx due to reduced combustion temperatures, while decreasing brake specific PM due to increased turbulence. Resulting performance calculations displayed a slight increase in fuel consumption. Chapter three analyzes the effects of ozone-assisted combustion on a single cylinder diesel engine. This work starts with a summarization of the literature in the field, which supports the simplified combustion model for determination of trends. Experimentation results demonstrate the addition of ozone causes a decrease in ignition delay, which produces slightly higher in-cylinder temperatures. Due to the elevated temperatures and ozone decomposition, NOx production increases, while PM decreases through radial atomic oxygen chemistry. Additionally, carbon monoxide emissions increase while hydrocarbon levels decrease. The changes in fuel consumption resulting from ozone injection are negligible. Of additional importance, this work verifies findings in the literature that demonstrate the effects of adding more ozone is negligible above a certain level of ozone injection (20 ppm in this effort). This is due to high concentrations of ozone facilitating its own destruction during the compression process of the engine.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Automotive engineering
Mechanical engineering
Diesel
Egr
Nox
Ozone
Pm
Reduction
Emission Reduction and Assisted Combustion Strategies for Compression Ignition Engines with Subsequent Testing on a Single-Cylinder Engine
Thesis
oai:kuscholarworks.ku.edu:1808/70162020-07-28T12:57:38Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
McDonald, Todd William
2011-01-03T05:02:25Z
2011-01-03T05:02:25Z
2009-11-30
http://dissertations.umi.com/ku:10683
http://hdl.handle.net/1808/7016
Cryopreservation of living cells and biological material by vitrification requires the expertise of a skilled lab technician and a large amount of time. Vitrification must be performed one sample at a time on tiny subjects, which makes for a tedious and unreliable process. Moreover, there is a lack of standardization in the methods for preparing cells and biological material for the vitrification process. The purpose of the Vitrification Machine is to greatly simplify the process by making it faster, more efficient, cheaper and more reliable. The machine will be capable of handling several subjects at a time and will completely automate the most tedious portions of the vitrification process. This ease of use will allow researchers to experiment with new vitrification preparation methods on a larger number of samples more quickly and reliably. The applications of the Vitrification Machine are wide, but it is specifically being developed to automate the vitrification of human oocytes and eventually embryos. Female patients diagnosed with diseases whose treatments are detrimental to the reproductive process (such as chemotherapy), can have their oocytes preserved for use after their treatment is complete. The automation of vitrification by the Vitrification Machine will make this process faster, more reliable, more affordable, and therefore more available to patients. There currently is no known product on the market that fills all these needs or has the potential to drive down the cost of this portion of the fertility preservation process. Since the Vitrification Machine will be useful to clinical In-Vitro Fertilization (IVF) laboratories, animal science research and fertility specialists in both research and clinical settings, the market potential of the product is very large.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Mechanical engineering
Design of Vitrification Machine
Thesis
oai:kuscholarworks.ku.edu:1808/226612020-06-23T19:56:26Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Cronk, Seymour H.
2017-01-19T14:56:28Z
2017-01-19T14:56:28Z
1930
http://hdl.handle.net/1808/22661
openAccess
This work is in the public domain and is available for users to copy, use, and redistribute in part or in whole. No known restrictions apply to the work.
Considerations involved in the extension of toll facilities into new territory
Thesis
oai:kuscholarworks.ku.edu:1808/53152018-01-31T20:08:09Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Alexander, John
2009-07-30T01:36:29Z
2009-07-30T01:36:29Z
2009-06-15
http://dissertations.umi.com/ku:10443
http://hdl.handle.net/1808/5315
A Langmuir probe study in BCl3, SF6, and mixtures of BCl3/SF6 capacitively-coupled plasmas is presented. In this study, energy distribution functions, electron temperatures (and average electron energy) and electron, positive ion, and negative ion densities were determined as a function of process conditions such as RF power, chamber pressure, and SF6 percentage in the total flow. With the addition of only 10% SF6 to the BCl3 plasma, the electron density rapidly halved to 5.7 x 108 cm-3, and the electron temperature sharply increased to ~4.3 eV (~1.1 eV increase). This is characteristic of electron attachment heating, whereby low energy electrons attach to species within the plasma, and the average energy of the fewer remaining electrons must increase in order to sustain the same power dissipation. These results confirm that the increased dissociation and enhancement in GaAs etch rate with SF6 added to BCl3 plasmas was due to electron attachment heating.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Chemical engineering
Electronics and electrical engineering
Physics
Fluid and plasma
Bcl3/sf6 plasma
Electron attachment
Langmuir probe
CHARACTERIZATION OF BCl₃, SF₆, and BCl₃/SF₆ PLASMAS USING LANGMUIR PROBE MEASUREMENTS
Thesis
oai:kuscholarworks.ku.edu:1808/81702020-08-14T13:59:30Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Narra, Hemanth
2011-10-09T04:18:15Z
2011-10-09T04:18:15Z
2011-08-31
http://dissertations.umi.com/ku:11724
http://hdl.handle.net/1808/8170
Aeronautical routing protocol (AeroRP) is a position-based routing protocol developed for highly dynamic airborne networks. It works in conjunction with the aeronautical network protocol (AeroNP). AeroRP is a multi-modal protocol that operates in different modes depending on the mission requirements. Ground station (GS) update mode is an AeroRP mode in which the GS sends geolocation or topology updates to improve routing accuracy. The main contribution of this thesis is to develop and implement the GS updates in AeroRP and analyse its performance in the various modes and compare them against canonical MANET routing protocols such as DSDV, OLSR, AODV, and DSR. The simulation analysis shows that AeroRP outperforms the traditional MANET protocols in various scenarios.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Computer engineering
Manet
Ns-3
Routing
Simulator
Tdma
Design and Performance Analysis of an Aeronautical Routing Protocol with Ground Station Updates
Thesis
oai:kuscholarworks.ku.edu:1808/223442018-07-23T16:02:18Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Akhbari, Bardiya
2017-01-02T20:07:53Z
2017-01-02T20:07:53Z
2016-08-31
http://dissertations.umi.com/ku:14870
http://hdl.handle.net/1808/22344
https://orcid.org/0000-0003-1874-7551
Athletes are frequently exposed to conditions that can result in bodily injuries, such as concussions and ankle sprains. This research is divided into two separate biomechanical studies: the design and evaluation of a device to simulate football helmet collisions and its parameters, and a cadaveric study to investigate the effects of ankle sprains. An impactor system was designed and built along with a computational model to simulate football helmet collisions, test helmet designs, and evaluate the influence of different parameters on head acceleration. Peak head accelerations of 20g to 60g, and rise times were targeted based on measures reported in the literature. A computational model of the impactor system was developed in Adams to determine design parameters such as neck stiffness and dampening. A pendulum impactor was constructed to achieve various impact energies by changing the release angle of the arm reaching up to 110 J. A dummy’s neck was designed as a single degree-of-freedom hinge joint with variable stiffness. Peak head accelerations agreed within 6% of literature reported accelerations. Similar to previous studies, the head reaches its peak acceleration in 10 to 12 ms. Neck stiffness did not affect the head peak acceleration during the 20 ms following impact. Moreover, the computational model revealed that adding a dampening of 1.75 N.s/mm to the neck results in 20 g decrease in the head peak acceleration. A second study aimed both to characterize the effects of collateral ankle ligament injuries using nine cadaveric ankle joints and to quantify the contribution of lower leg muscle forces to the ankle joint kinematics. Intact ankles were tested, then anterior talofibular (ATFL) and calcaneofibular (CFL) ligaments were sequentially resected to simulate two grades of ankle injury. The tibialis anterior (TA) and extensor digitorum longus (EDL) tendons were loaded with static weights and distributed based on their physiological cross sectional area. Weak TA and Weak EDL configuration were simulated by reducing their respective muscle loads by 50%. The ankle was moved from full dorsiflexion to plantarflexion using a stepper motor attached to Achilles tendon. The effect of muscle configuration (Weak TA and Weak EDL) and injuries (ΔATFL and ΔATFL-CFL) compared to baseline (intact ankle with physiological load set) on the measured ankle joint kinematics was determined using a repeated measures ANOVA. The weaker EDL demonstrated 1° to 3° higher inversion than physiological loads through the cycle significantly. After the simulated ATFL-CFL injury, the trials demonstrated a 2° increase in inversion with respect to intact ankle kinematics in dorsiflexion. The required Achilles’ load increased by up to 24% in plantarflexion after the injury indicating a significant reduction in efficiency. Based on the higher inversion results in weaker muscle set, strengthening the EDL might help to prevent the hyper inversion injuries.
en
openAccess
Copyright held by the author.
Biomechanics
Mechanical engineering
Biomedical engineering
Ankle Sprain
Computational Modeling
Concussion
Helmet Examintation
Neck Stiffness
Pendulum Impactor
Biomechanical Analyses of Head Acceleration during Contact Sports and Ankle Joint Complex Injury
Thesis
oai:kuscholarworks.ku.edu:1808/275902020-10-13T20:00:45Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Ghimire, Krishna Prasad
2019-01-01T20:56:30Z
2019-01-01T20:56:30Z
2018-05-31
http://dissertations.umi.com/ku:15734
http://hdl.handle.net/1808/27590
https://orcid.org/0000-0003-0406-6691
Headed reinforcing bars serve as a viable alternative to hooked bars for anchorage in concrete because they provide a more efficient anchorage mechanism and limit congestion of the reinforcement. This study is part of a comprehensive study of the anchorage behavior of the headed bars. The work described in this report includes tests of 32 No. 8 headed bars anchored in simulated column-foundation joints represented by bars anchored in slabs, all but two with reinforcement in the plane of the slab, and six lapped-slplice specimens without confining reinforcement containing No. 6 headed bars and an analysis of these tests along with test results from 23 studies by other researchers of 84 exterior, seven roof-level interior, and seven knee beam-column joints subjected to reversed cyclic loading. The headed bars in the column-foundation joint specimens had net bearing areas ranging from 4 to 15 times the area of the bar Ab; some of the headed bars contained large obstructions adjacent to the bearing face of the head that exceeded the dimensional limits for HA heads in ASTM A970-16; embedment lengths ranged from 6 to 8.5 in.; reinforcement in a plane perpendicular to the headed bars included combinations of bars placed symmetrically about the headed bar, parallel and close to the long edges of the specimen, bars placed symmetrically about and close to the headed bar in the short direction of the specimen, and bars oriented in both the long and short directions of the specimen; concrete compressive strengths ranged from 4,200 to 8,620 psi; and stresses in the bars at failure ranged from 49,500 to 117,000 psi. The No. 6 headed bars had a net bearing area of 4Ab and a lap length of 12 in. The center-to-center spacing between the spliced bars was 1.67, 2.33, or 3.53 bar diameters db; clear concrete cover to the bars was 2 in.; concrete compressive strengths averaged 6,360 and 10,950 psi; and stresses in the bars at failure ranged from 75,010 to 83,560 psi. For the beam-column joints subjected to reversed cyclic loading, headed bar sizes ranged between D12 (No. 4) and D36 (No. 11), net bearing areas ranged from 1.7 to 11.4Ab, and embedment lengths ranged from 8 to 22.6db; concrete compressive strengths ranged from 3,480 to 21,520 psi and steel yield strengths ranged from 53,650 to 149,930 psi; all but four specimens contained hoops, spaced at 2.2 to 6.8db (1.8 to 5.9 in.), as confining reinforcement parallel to the headed bar within the joint region; clear cover and minimum center-to-center spacing between the bars ranged from 1.4 to 9.9db and from 2 to 11.2db, respectively. Experimental anchorage strengths are compared with values based on descriptive equations for anchorage strength and design provisions for development length of headed bars for members with concrete compressive strengths up to 16,000 psi and steel yield strengths up to 120,000 psi that recognize the contribution of confining reinforcement without specifying minimum limits on bar spacing or clear cover. The descriptive equations and design provisions were developed based on tests of simulated beam-column joints under monotonic loading as part of the comprehensive study. The comparisons are used to expand the applicability of the descriptive equations to members subjected to reversed cyclic loading and develop simplified design guidelines allowing for the use of headed reinforcing bars in wide range of reinforced concrete members. Changes in the provisions of ACI 318-14 for the development length of headed bars and in ASTM A970 for head dimension requirements are also proposed. The results of this study show that reinforcement perpendicular to headed bars in column-foundation joints does not improve the anchorage strength. Headed bars with obstructions exceeding the dimensional limits for HA heads in ASTM A970-16 provide adequate anchorage strength. Headed bars did not provide sufficient anchorage in knee beam-column joints subjected to reversed cyclic loading. The descriptive equations and proposed design provisions developed based on headed bars in beam-column joint specimens tested under monotonic loading, in which the anchorage strength of the headed bar is a function of embedment length, concrete compressive strength, bar spacing, bar diameter, and confining reinforcement within the joint region, are applicable to a wide range of reinforced concrete members, including beam-column joints subjected reversed cyclic loading, lap splices, and column-foundation joints, and allow the minimum clear spacing of 3db between headed bars permitted in joints in special moment frames in accordance with Section 18.8.5.2 of ACI 318-14 to be reduced to 1db, allowing for the use of more closely spaced headed bars. The anchorage strength of the headed bars calculated using anchorage provisions of Chapter 17 of ACI 318-14 with a strength reduction factor of 1.0 provides a very conservative and highly variable estimate of anchorage strength for headed bars compared to the proposed design provisions.
en
openAccess
Copyright held by the author.
Civil engineering
anchorage
beam-column joint
bond and development
headed bar
high-strength steel and concrete
reversed cyclic loading
ANCHORAGE OF HEADED REINFORCING BARS IN CONCRETE
Dissertation
oai:kuscholarworks.ku.edu:1808/53132020-07-24T12:45:01Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Haines, Michael
2009-07-30T01:24:24Z
2009-07-30T01:24:24Z
2009-06-05
http://dissertations.umi.com/ku:10418
http://hdl.handle.net/1808/5313
Background. Following a balance disturbance, one or more steps are often taken. Studies have shown that older adults are more likely than young adults to take multiple steps, and that number of steps is a predictor of fall risk. In order to better understand how a stepping strategy is chosen, we investigated the transition between single and multiple stepping strategies in young adults. Methods. Each participant responded to a sudden release from an initial forward lean. We limited available first step length with a visible boundary line to induce transitions between single and multiple stepping strategies. The available step length where the transition occurred (transition threshold) and the biomechanics of the first step on either side of the transition were quantified in terms of temporal, kinematic, and kinetic parameters. Results. The magnitude of the transition threshold displayed hysteresis sensitive to direction of the transition (single to multiple steps versus multiple to single steps). Step liftoff, swing, and landing times, step length, step length boundary margin, and braking forces during landing were different on either side of the transition. Discussion. If transition threshold is used as a clinical measure, the method used to detect the threshold should be further studied. More sophisticated threshold detection protocols may minimize hysteresis. Biomechanical changes in the first step suggest that the second step is planned before liftoff of the first step, rather than only after failure of the first step to recover balance.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Mechanical engineering
Biomedical engineering
Balance
Balance recovery
Forward lean
Step length
Threshold
Upright stance
Transition between single and multiple stepping strategies in forward fall recovery
Thesis
oai:kuscholarworks.ku.edu:1808/87912018-01-31T20:07:58Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Kheyfets, Vitaly O.
2012-03-01T22:46:40Z
2012-03-01T22:46:40Z
2011-08-31
http://dissertations.umi.com/ku:11705
http://hdl.handle.net/1808/8791
HIV is a growing concern worldwide. With slow progress in the development of a vaccine, researchers have turned to alternate methods of preventing the spreading of HIV as a result of unprotected sexual intercourse. Developing a mechanism capable of protecting the vaginal or rectal epithelium from sexually transmitted pathogens can be an effective tool in the prevention of HIV infection. One such tool can come in the form of a microbicide gel, which provides a physical barrier and acts as a delivery vehicle for its active ingredient. In order for the microbicide to be an effective barrier and delivery vehicle, it must have the capability to coat the epithelium for a specific amount of time and sustain its structural integrity under the influence of gravity and other perturbation forces. In addition, to be used as a drug delivery vehicle the microbicide must serve the following functions: coat the surface completely without leaving any of the surface exposed, stay on the surface while influenced by external forces such as gravity and squeezing, and be able to contain potent concentrations of one or more active microbicidal ingredients. Many currently available vaginal spermicidal gels are applied using a syringe-like applicator. After vaginal application, several physical forces will perturb the gel: gravity, squeezing, surface tension and shearing. In this document I will outline the work that has been completed, for an original PhD dissertation, on the mathematical and experimental analysis of microbicide vaginal gels. This document contains an in-depth discussion of the methods taken to satisfy the following engineering goals: 1. An instrument/method for conducting gravity-induced flow experiments and obtaining spreading characteristics along with surface topography. 2. A numerical solution for a non-linear, second-order, partial differential equation that governs the evolution of the free surface of a spreading fluid. 3. A derivation and numerical solution for the 3-D power-law evolution equation. 4. A derivation and numerical solution for the 3-D Ellis evolution equation. All experimental and computational simulations presented in this study involve a finite bolus of fluid, with non-Newtonian viscous properties, spreading on an inclined plane under the influence of gravity. Using the two numerical models presented in this document, I conducted an in-depth parameter and parameter sensitivity analysis of the power-law model, and a parameter study of the Ellis model. Combining the experimental data with computational simulations allowed me to make the following conclusions: 1. Accounting for lateral slumping in the computational simulation will improve the theory's agreement with experiment. 2. Approximating the initial condition to disregard complex curvatures on the free surface, and only consider gross geometric parameters, will not compromise theoretical model's agreement with experiment. 3. The 3-D power-law model provides a sufficient approximation of Hydroxyethylcellulose (HEC) spreading under the influence of gravity, for gels at 2.4-3.0% HEC concentration. Furthermore, implementing a constitutive equation that accounts for the low-shear Newtonian plateau (Ellis constitutive eq.) does not improve the models agreement with experiment enough to justify its added complexity. In conclusion, the following work provides an original experiment and a computational simulation of non-Newtonian fluid spreading. It is my hope that this work can be used by researchers in the field of microbicide development and any other scenario where free surface flow of non-Newtonian fluids is applicable.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Biomedical engineering
Engineering
Mechanical engineering
Ellis
Free-surface flow
Microbicides
Non-newtonian
Power-law
Mathematical and Experimental Analysis of Microbicide Vaginal Gels
Dissertation
oai:kuscholarworks.ku.edu:1808/40532018-10-31T15:19:03Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Pierson, Matthew Charles
2008-08-05T04:39:00Z
2008-08-05T04:39:00Z
2008-04-30
http://dissertations.umi.com/ku:2506
http://hdl.handle.net/1808/4053
https://orcid.org/0000-0002-2067-5377
Current practice for designing laterally loaded columns that pass through an MSE Wall involves isolating the column from the MSE mass and anchoring the column into rock with a rock socket. A sizeable cost and time savings could be realized, while still maintaining reliability, if a method were available to evaluate the lateral load capacity of a column that is supported by the MSE mass with no rock socket. This report describes the construction, instrumentation, and testing of eight different 36" diameter columns solely supported by an MSE mass as well as a brief discussion of the results and recommendations for future testing and analysis. Instrumentation includes 24 pressure cells, 16 inclinometer locations, 112 strain gages, 20 tell tales, 84 photo measurements of the wall facing, and load cells and LVDTs associated with lateral load and response.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Civil engineering
Shaft
Mse wall
Laterally loaded
Mse block wall
Columns
Behavior of Laterally Loaded Shafts Constructed Behind the Face of a Mechanically Stabilized Earth Block Wall
Thesis
oai:kuscholarworks.ku.edu:1808/257662018-09-20T19:28:13Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Shi, Lei
2018-01-28T23:09:06Z
2018-01-28T23:09:06Z
2016-08-31
http://dissertations.umi.com/ku:14743
http://hdl.handle.net/1808/25766
This dissertation investigates the feasibility of creating a multichannel sense and avoid radar system for small fixed-wing UAVs (also known as sUAS or drones). The target sUAS is a 40% Yak-54 remote controlled aircraft with a typical payload of 10 lbs. Small UAS’s such as these are increasing in popularity for both personal, commercial, and government use including precision agriculture, infrastructure monitoring, and assisting first response. However, due to their lack of situation awareness, the FAA has placed strict regulations on their operation limiting their use on both the civil and government sides across the U.S. This miniature radar system is intended to provide these sUAS with target detection, tracking, and 3-D location and velocity information on potential non-cooperative hazards, primarily focusing on general aviation (GA) aircraft. The resulting FMCW miniature radar system has a size weight and power (SWaP) that is suitable for installing onboard the 40% Yak-54 UAS with the exception of replacing a TX power amplifier and has demonstrated, through measuring moving cars, that it is capable of target detection using a 2-D FFT processing algorithm and a constant false alarm rate (CFAR) detector. Tracking of the target was performed using the range-Doppler relationship of targets in the resulting radar image. The target’s angular information in the form of target echo angle of arrival (AoA, needed for location estimation) was estimated using interferometry. While the angular estimations were in the right direction, their uncertainties resulting in significant fluctuations in estimated target XYZ position and XYZ velocities. It was observed that in the near term, averaging the AoA (which changes relatively slowly for steady flight) is a way to reduce this uncertainly. In the future, the radar system needs to be upgraded so that it can provide the ideal 10-Hz update rate which will also provide sufficient data for more complex target AoA detection algorithms.
en
openAccess
Copyright held by the author.
Electrical engineering
collision avoidance
Radar
UAS
Multichannel Sense and Avoid Radar for Small UAVs
Dissertation
oai:kuscholarworks.ku.edu:1808/219762018-01-31T20:07:51Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Giridhar, Rohith
2016-11-15T22:21:40Z
2016-11-15T22:21:40Z
2016-05-31
http://dissertations.umi.com/ku:14610
http://hdl.handle.net/1808/21976
The preliminary step in the computational study of mitigating the aerodynamic noise generated by wind turbine blades involves accurate prediction of aerodynamic noise generated by a wind turbine rotor which can be used a basis for comparison. The NREL Phase VI HAWT rotor has been chosen to perform this study. This is achieved by first predicting the three dimensional flow field around the rotor through CFD analysis using SST k-ω turbulence model for wind speeds of 7m/s, 10m/s, 13m/s and 15m/s. CFD analysis has been performed using the rotating reference frame method at steady state conditions which resulted in predicting the flow field accurately with less computational time. The rotational periodic boundary condition with 1800 symmetry has been used with which one blade has been simulated instead of two. This reduced the mesh size and thus computational costs to perform the CFD analysis. To validate the prediction of flow field obtained through CFD analysis, performance characteristics and aerodynamic characteristics such as torque generated and trends of pressure coefficients at different span locations are validated against the time averaged experimental results and other results pertaining to the same published in previous computational study. The results obtained through CFD analysis show good agreement with both experimental results and previous computational results. Based on the trends of pressure coefficients predicted for different wind speeds we see that it is most accurate at a wind speed of 7m/s and this accuracy gradually decreases with increase in wind speed. Once the flow field was accurately predicted, this was used to predict both the location and magnitude of aerodynamic noise generated by the blade using the Curle broadband noise source model. Aeroacoustic analysis indicates that major noise sources are located near the tip of the blade and it gradually decreases as we move towards its root. This trend is observed at all four wind speed conditions. It is also observed that with increase in wind speeds, there is increase in the intensity of noise generated by the blades and thus increase in Sound Power Level across the blade.
en
openAccess
Copyright held by the author.
Aerospace engineering
Aero acoustics
Aerodynamic Noise
Curle
NREL Phase VI
SST k-omega
Wind Turbine Noise
Prediction of Aerodynamic Noise Generated By Wind Turbine Blades
Thesis
oai:kuscholarworks.ku.edu:1808/275972019-01-16T19:36:28Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Mendoza Strilchuk, Pedro
2019-01-01T21:15:21Z
2019-01-01T21:15:21Z
2018-05-31
http://dissertations.umi.com/ku:15825
http://hdl.handle.net/1808/27597
Airborne and spaceborne radar has long been an effective tool for remote sensing, surveillance, and reconnaissance. Most airborne systems utilize antenna arrays that are installed inside the moldline of the aircraft or in radomes that protect the array from in-flight loads. While externally-mounted arrays can offer the advantage of larger apertures, sensor-vehicle interactions often result in performance degradation of both systems. The presence of an externally-mounted array will increase the vehicle’s drag and potentially affect the dynamics and control of the vehicle. In addition, in-flight structural loads will deform the array, thus resulting in relative phase errors. While there exist a multitude of physics-based simulation tools to determine the effects of the array on the aircraft performance, existing tools are not sufficient for generating deformed arrays necessary for determining in-flight array performance. In response to this need, a computer tool for analyzing antennas undergoing structural loads is developed. The Antenna Deformation Tool (ADT) has two primary uses: generating deformed geometry from the output of a structural Finite Element Model (FEM) for use in an Electromagnetic (EM) simulation, and designing conformal antenna arrays. The two commercial software packages ADT is optimized for are MSC NASTRAN and ANSYS HFSS. Specifically, ADT is designed to generate a deformed 3D Computer Aided Design (CAD) model from a NASTRAN structural mesh. The resulting CAD model is compatible with HFSS electromagnetic simulation software for the assessment of the effects of loads on performance. The main purpose for the development of ADT is to facilitate studies of how structural deformations affect airborne antenna arrays performance and to provide the capability to perform studies easily and quickly using different antennas on the same structural model. ADT capabilities are demonstrated using several representative airborne antenna array structures. ADT is also demonstrated in the design of conformal antenna arrays. ADT can import CAD geometry and deform it according to a prescribed deformation field. The deformation field can either be determined from structural simulations or be provided by the user. This functionality allows the user to take an existing planar antenna design and conform it to a desired shape. Within the scope of airborne antenna arrays, this would allow an engineer to conform the antenna to the moldline of the aircraft or other support structure. Currently, ADT can interpret only quad and triangular 2D elements from NASTRAN. In addition, its ability to interpret a surface from a point cloud is limited to surface meshes in which there are exactly four explicit vertices, or surfaces which have a fairly even boundary with no major discontinuities and can be divided into four even segments. ADT is tested on NASTRAN structural models of small to medium complexity, and the geometry generated from simple models is used in HFSS simulations with success (with occasional post processing required). The antenna deformation submodule shows favorable performance with sheet and solid CAD geometry, though post-processing is required in the case of the latter. Results of some deformed antennas simulated with HFSS in the 200 MHz range are presented. The surface error of the geometry produced by ADT varies with the type of input mesh, with curved meshes and surfaces having higher errors. In terms of average element edge length, the maximum surface error is up to 1% for surfaces with no to small curvatures, and up to 3.6% for highly curved surfaces. This translates to about 0.17% of the mesh diagonal. ADT contains a set of classes and functions which provide ample capabilities for surface generation from meshes, and the process implemented is mostly automatic, requiring minimal user intervention. Due to ADT defining deformed geometry purely on separate meshes, adjacent surfaces are not associative and continuity between them is not guaranteed, which inherently can result in small intersections. These intersections can cause meshing problems with HFSS; however, these issues can be mitigated by adding a small offset. While demonstrated applications are still limited, ADT promises to substantially contribute to the design of aircraft-integrated antennas and multifunctional structures. With very limited capabilities for generating and assessing deformed antenna geometry currently existing, ADT represents a unique tool. ADT could be used not only in developing the next-generation of airborne remote sensing technologies, but to characterize in-flight performance of existing systems as well.
en
openAccess
Copyright held by the author.
Remote sensing
Aerospace engineering
antenna
B-splines
confromal
remote sensing
simulation coupling
Structural-Electromagnetic Simulation Coupling and Conformal Antenna Design Tool
Thesis
oai:kuscholarworks.ku.edu:1808/97092020-09-03T13:37:07Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Zhang, Yuanyuan
2012-06-03T13:50:12Z
2012-06-03T13:50:12Z
2012-05-31
http://dissertations.umi.com/ku:11963
http://hdl.handle.net/1808/9709
The purpose of this research is to provide a comprehensive study of spectrally efficient multicarrier systems for fiber-optic transmission. Multicarrier optical systems partition a high-data rate digital signal in a wavelength channel into multiple subcarriers. The data rate on each subcarrier can be sufficiently low and thus, the tolerance to transmission impairments can be significantly improved. Although different modulation and detection techniques are used, all the multicarrier systems investigated in this dissertation achieve a high spectral efficiency of 1 Baud/s/Hz. Orthogonal frequency-division multiplexing (OFDM) and Nyquist wavelength-division multiplexing (Nyquist-WDM) are the two basic approaches to achieve the 1 Baud/s/Hz spectral efficiency. OFDM allows spectral overlap of adjacent subcarriers and crosstalk elimination by integration at the receiver; Nyquist-WDM limits the spectral spreading of each subcarrier channel to the symbol rate per subcarrier to avoid spectral overlap. In terms of detection method, both direct detection and coherent detection can be applied in multicarrier systems. This dissertation focuses on the use of three high spectral efficiency optical multicarrier systems. In the theoretical and experimental investigation of a 11.1Gb/s FFT-based OFDM system, a simple dual-drive Mach-Zehnder modulator (MZM) was employed in the transmitter and direct detection in the receiver, which provided an OFDM system implementation with reduced complexity. The data was transmitted through 675km uncompensated standard single-mode fiber (SMF). Next, a 22.2Gb/s digital subcarrier multiplexing based (DSCM-based) OFDM system was used in conjunction with 10 subcarrier channels using QPSK modulation. In this system, an IQ modulator was utilized in the transmitter and coherent detection in the receiver. By using coherent detection, the receiver was able to dynamically select the desired subcarrier channels for detection without changing the system configuration. The present research also explored a 22.2Gb/s 10 subcarrier Nyquist-WDM system with coherent detection, compared its system performance with OFDM systems, and subsequently examined the impact of filter roll-off factor. Finally, a systemic comparison of the three proposed multicarrier systems was performed in terms of their transmission performance and system flexibility. The design tradeoffs were analyzed for different applications and summarized principles for the modern multicarrier fiber-optic system design.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Electrical engineering
Dscm
Fiber-optic transmission
High spectral efficiency
Multicarrier systems
Nyquist-wdm
Ofdm
SPECTRALLY EFFICIENT MULTICARRIER SYSTEMS FOR FIBER-OPTIC TRANSMISSION
Dissertation
oai:kuscholarworks.ku.edu:1808/129852020-10-22T13:23:47Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Cetinkaya, Egemen Kemal
2014-02-05T16:42:41Z
2014-02-05T16:42:41Z
2013-12-31
http://dissertations.umi.com/ku:13157
http://hdl.handle.net/1808/12985
https://orcid.org/0000-0002-6394-4565
Communication networks, in particular the Internet, face a variety of challenges that can disrupt our daily lives resulting in the loss of human lives and significant financial costs in the worst cases. We define challenges as external events that trigger faults that eventually result in service failures. Understanding these challenges accordingly is essential for improvement of the current networks and for designing Future Internet architectures. This dissertation presents a taxonomy of challenges that can help evaluate design choices for the current and Future Internet. Graph models to analyse critical infrastructures are examined and a multilevel graph model is developed to study interdependencies between different networks. Furthermore, graph-theoretic heuristic optimisation algorithms are developed. These heuristic algorithms add links to increase the resilience of networks in the least costly manner and they are computationally less expensive than an exhaustive search algorithm. The performance of networks under random failures, targeted attacks, and correlated area-based challenges are evaluated by the challenge simulation module that we developed. The GpENI Future Internet testbed is used to conduct experiments to evaluate the performance of the heuristic algorithms developed.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Electrical engineering
Computer science
Computer engineering
Challenge
Experimentation
Graph algorithm
Resilience
Simulation
Modelling and Design of Resilient Networks under Challenges
Dissertation
oai:kuscholarworks.ku.edu:1808/259212018-02-07T19:40:39Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Gowravaram, Saket Navalur
2018-02-06T02:36:33Z
2018-02-06T02:36:33Z
2017-08-31
http://dissertations.umi.com/ku:15541
http://hdl.handle.net/1808/25921
This thesis focuses on the development and testing of the KHawk multispectral remote sensing system for environmental and agricultural applications. KHawk Unmanned Aircraft System (UAS), a small and low-cost remote sensing platform, is used as the test bed for aerial video acquisition. An efficient image geotagging and photogrammetric procedure for aerial map generation is described, followed by a comprehensive error analysis on the generated maps. The developed procedure is also used for generation of multispectral aerial maps including red, near infrared (NIR) and colored infrared (CIR) maps. A robust Normalized Difference Vegetation index (NDVI) calibration procedure is proposed and validated by ground tests and KHawk flight test. Finally, the generated aerial maps and their corresponding Digital Elevation Models (DEMs) are used for typical application scenarios including prescribed fire monitoring, initial fire line estimation, and tree health monitoring.
en
openAccess
Copyright held by the author.
Aerospace engineering
Multispectral Remote Sensing of the Earth and Environment Using KHawk Unmanned Aircraft Systems
Thesis
oai:kuscholarworks.ku.edu:1808/304922021-03-05T16:54:48Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Andrews, Ron
2020-06-14T21:31:31Z
2020-06-14T21:31:31Z
2019-12-31
http://dissertations.umi.com/ku:16872
http://hdl.handle.net/1808/30492
https://orcid.org/0000-0002-3056-4953
In George Orwell’s `nineteen eighty-four: A novel', there is fear regarding what “Big Brother”, knows due to the fact that even thoughts could be “heard”. Though we are not quite to this point, it should concern us all in what data we are transferring, both intentionally and unintentionally, and whether or not that data is being “leaked”. In this work, we consider the evolving landscape of IoT devices and the threat posed by the pervasive botnets that have been forming over the last several years. We look at two specific cases in this work. One being the practical application of a botnet system actively executing a Man in the Middle Attack against SSH, and the other leveraging the same paradigm as a case of eavesdropping on Internet Protocol (IP) cameras. For the latter case, we construct a web portal for interrogating IP cameras directly for information that they may be exposing.
en
openAccess
Copyright held by the author.
Computer science
Authentication
Credential Harvesting
Eavesdropping
IoT
IP Camera
Man in the Middle
Evaluating the Proliferation and Pervasiveness of Leaking Sensitive Data in the Secure Shell Protocol and in Internet Protocol Camera Frameworks
Thesis
oai:kuscholarworks.ku.edu:1808/45162018-01-31T20:08:03Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Kim, Kyungpyo
2009-04-28T04:20:32Z
2009-04-28T04:20:32Z
2009-01-01
http://dissertations.umi.com/ku:10241
http://hdl.handle.net/1808/4516
Composite fiber reinforced plastics are being given favorable consideration for emerging applications in large aperture telescopes, such as the Hubble telescope or communication dishes. Many lightweight mirror fabrication concepts are currently being pursued. Presently, the technology is limited because it has an incomplete understanding of the mechanics associated with quasi-isotropic laminates for diffraction-limited displacement constraints, and lack of understanding for effects of resin buffer layers on composite mirrors for high surface smoothness. In this dissertation document, radial stiffness associated with stacking sequence effects in quasi-isotropic laminates (pi/n, where n=3, 4, and 6) and dimensional stability in the composite laminates are investigated numerically. The numerical results show that directional dependency of flexural stiffness in the laminates, which is strongly associated with stacking sequences, is a significant factor causing unfavorable sinusoidal surface waviness. The maximum radial flexural stiffness variation is found as ±12.85% in pi/3 laminate while a minimum of ±5.63% is found in pi/4 laminate. Mechanics of maximum asymmetry by ±2º misorientation based on ideal pi/n laminate lay-ups are evaluated and the results are compared with ideal lay-up sequence cases. The calculated extensional and flexural stiffness values from the maximum asymmetric cases are within less than 0.05%. As such, the radial flexural stiffness variations in quasi-isotropic laminates are shown to be more problematic than asymmetry caused by common manufacturing variance. The types of surface deformations in quasi-isotropic laminates associated with directional dependency of flexural stiffness are evaluated using finite element analyses. Also, fiber print-through in replicated composite mirrors and the effects of the resin buffer layer present in the mirrors for mitigation of the fiber print-through are investigated and discussed. Numerical results reveal that there will be an unfavorable sinusoidal surface deformation in each ideal pi/n laminate and the shapes are strongly associated with principal fiber directions due to stacking sequence effects. The surface deformations in quasi-isotropic laminates are shown to be typical and such surface deformations are inevitable when composite mirrors are fabricated from discrete layers of anisotropic carbon fiber reinforced plastics. Moreover, the use of additional resin layers appears to more adversely influence the composite mirror substrates. The validation of predicted surface deformations and dimensional distortions are achieved by comparing experimental results on a 8-inch-diameter composite mirror sample fabricated at the University of Kansas Dept. of Aerospace Engineering (KUAE) and Bennett Optical Research (BOR). A study of quasi-homogeneous materials such as short fiber products as alternative composite materials is investigated. Furthermore, the relation between resin property effects and corresponding resin thickness effects is evaluated and discussed. The analyses provide information on alternative types of materials that primarily affect optical performance and thus are most important for precision optics. Based on the results, locally varying radial surface deformations in quasi-isotropic laminates fabricated from continuous fiber reinforced plastics distort optical performance. These surface deformations might be eliminated by utilizing short fiber materials and a soft resin system with a very low coefficient of thermal expansion compared to conventional resins.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Aerospace engineering
Dimensional stability in composite mirrors
Quasi-isotropic laminate mirrors
Stiffnesses in composite mirrors
Surface deformation in composite mirrors
Flexural Stiffnesses of and Dimensional Stability in Circular Quasi-isotropic Laminate Mirrors
Dissertation
oai:kuscholarworks.ku.edu:1808/106302020-09-22T13:24:08Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Acharya, Raju
2013-01-20T15:10:31Z
2013-01-20T15:10:31Z
2012-12-31
http://dissertations.umi.com/ku:12561
http://hdl.handle.net/1808/10630
Reinforced concrete box culverts are mostly used at shallow depths. Periodic evaluation of their load carrying capacities is required for load rating of the culvert by determining a rating factor (RF) or truck tonnage of a HS truck. The rating factor is defined as the capacity of the structure minus the dead load demand, and then divided by the live load demand. All the state DOTs are required to inspect and assess culvert conditions and capacities by load rating in every two years. The distribution of live loads on the top slab of a box culvert plays a major role in determining the rating factor of the culvert. The current AASHTO guidelines do not consider the effects of pavements present above the fill while determining the load distribution. The distribution of the wheel load through a pavement may be different from that suggested by the current AASHTO guidelines. In addition to the pavement effect, the fill conditions (i.e., fill thickness and fill modulus) may affect the load distribution. Currently, there is lack of a design method to address the load distribution when a pavement is present above the fill. In this research, two field tests were carried out on the culverts under rigid and flexible pavements respectively. The finite difference numerical models of the test culverts were created in the Fast Lagrangian Analysis of Continua in 3 Dimensions (FLAC3D) software and were verified against the field test results. The verified finite difference models of the culverts were used for a parametric study to analyze the effects of pavement type (i.e., flexible and rigid pavement), pavement thickness, fill depth, and culvert span on the pressure distribution. The material properties and boundary conditions used in the models for the parametric study were similar to the verified models. The parametric study demonstrated that the intensity of vertical pressure on the top slab of the culvert gradually decreased as the pavement thickness increased. The vertical pressure under a rigid pavement was lower than that under a flexible pavement at the same pavement thickness. Within the range of the fill depth covered in this study, the intensity of vertical pressure decreased gradually with an increase of the fill depth over the culvert. The effect of the traffic load on the vertical pressure on the culvert was more significant at the lower fill depth and gradually decreased with the increase of the fill depth. The distribution of the vertical pressure at the fill depth of 0.6 m was characterized by a peak pressure under the wheel load and the peak pressure shifted to the middle of the axle at the fill depth of 1.2 m and greater. There was little interaction between the wheels at the fill depth of 0.6 m and, the interaction between the wheel loads was fully developed for the fill depth of 1.2 m and greater. The calculated vertical pressure decreased by increasing the culvert span from 1.8 to 5.4 m when the top slab thickness of the culvert was the same. However, when the top slab thickness increased, the vertical pressure at the larger span was close to that at the small span. The effect of the culvert span on the vertical pressure was negligible if the thickness of the top slab was properly designed. The maximum vertical pressure obtained from the numerical analysis was compared with those by the distribution formulae in the AASHTO guidelines. The comparison showed that the current AASHTO guidelines over-estimated the pressure for low-fill culverts under a pavement. Simplified methods were developed in this study to estimate the vertical pressures under rigid and flexible pavements. In the case of the culvert under a rigid pavement, the total wheel load is distributed uniformly over the combined area with the extremities of the distributed areas by individual wheels. In the case of the culvert under a flexible pavement, the vertical pressure within the overlapped area is obtained by the superposition of the pressures due to individual wheels. The calculated vertical pressures by the simplified methods were in good agreement with the maximum vertical pressures obtained by the numerical method.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Civil engineering
Box structures
Load rating
Model verification
Pressure distribution
Simplified method
Improved Load Distribution for Load Rating of Low-Fill Box Structures
Thesis
oai:kuscholarworks.ku.edu:1808/62882018-01-31T20:08:11Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Crain, Joshua Sakumura
2010-06-09T03:34:55Z
2010-06-09T03:34:55Z
2010-04-20
http://dissertations.umi.com/ku:10794
http://hdl.handle.net/1808/6288
A common technique used to prevent the propagation of cracks in bridge girders is drilling crack-stop holes at the crack tips. By doing so, stress concentrations at the tip of the cracks are reduced and fatigue life of the bridge is extended. The size of the crack-stop hole is determined by utilizing known material properties and relationships developed through experimentation. However, these equations often result in a crack-stop hole diameter larger than can be practically drilled; therefore, physical limitations force crack-stop holes to be undersized in the field. To raise the effectiveness of the undersized holes to that of full-sized holes, a method is needed to strengthen undersized crack-stop holes. A similar problem was reported in the aerospace industry with fastener holes, which are potential sites for cracks to initiate and propagate. Static mechanical coldworking generated a great deal of interest in the 1970s and was among several processes that were investigated for improving fatigue life of fastener holes. Extensive literature exists showing that static coldworking of fastener holes can increase fatigue-life-to-failure by a factor from three to ten, depending on stress range. The purpose of this study is to develop a technique to improve the fatigue lives of undersized, crack-stop holes. The technique under development uses piezoelectric transducers operated at ultrasonic frequencies to improve upon recognized coldworking techniques. The piezoelectric transducers duplicate the residual compressive stresses produced by static cold expansion and hopefully change grain size. These residual compressive stresses act as a barrier to crack initiation by reducing the stress concentration at the hole. In addition, this new technique is expected to change the crystalline structure of the steel in the immediate vicinity surrounding the under-sized hole. It is thought that the excitation from the piezoelectric transducers will refine the grain size and create a more uniform grain size thereby improving fatigue performance. A tool is being developed that utilizes the piezoelectric transducers ability to convert electrical signals into mechanical work. Initially, the tool being developed is a small-scale laboratory device; once the technique is proven, it will be scaled up for use on full-scale bridge members under laboratory conditions. Lastly, a tool using the same technology will be developed for field application. The research includes a set of finite element models created to aid in tool design and to quantify and characterize the residual stresses surrounding the cold expanded crack-stop holes. Results were compared and agreed quite favorably to analyses found in past literature.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Civil engineering
Bridges
Cold working
Crack-stop holes
Fatigue cracks
Fatigue enhancement
Fatigue Enhancement of Undersized, Drilled Crack-Stop Holes
Thesis
oai:kuscholarworks.ku.edu:1808/144122019-07-26T16:59:12Zcom_1808_231com_1808_1260col_1808_18153col_1808_7158
Carpenter, C. B.
Brown, H. R.
2014-07-01T17:32:26Z
2014-07-01T17:32:26Z
1915
http://hdl.handle.net/1808/14412
en
openAccess
This work is in the public domain according to U.S. copyright law and is available for users to copy, use, and redistribute in part or in whole. No known restrictions apply to the work.
The Cherokee and Crawford County Coal Field With Analyses of the Coal
Thesis
oai:kuscholarworks.ku.edu:1808/85372020-08-27T14:29:33Zcom_1808_231com_1808_1260col_1808_18153col_1808_7158
Grignard, Emily E.
2011-11-23T21:22:27Z
2011-11-23T21:22:27Z
1913-02-07
http://hdl.handle.net/1808/8537
en_US
openAccess
This work is in the public domain according to U.S. copyright law and is available for users to copy, use, and redistribute in part or in whole. No known restrictions apply to the work.
The Deodorizing and Decolorizing of Degras
Thesis
oai:kuscholarworks.ku.edu:1808/296302020-10-12T13:59:30Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Ameen, Shahedreen
2019-10-15T16:32:54Z
2019-10-15T16:32:54Z
2019-05-31
http://dissertations.umi.com/ku:16339
http://hdl.handle.net/1808/29630
https://orcid.org/0000-0002-0532-5838
The use of high-strength steel in diagonally reinforced coupling beams was investigated with the aims of minimizing reinforcement congestion and increasing the maximum permissible design shear stress without compromising behavior under large displacement reversals. Five large-scale diagonally reinforced concrete coupling beam specimens with clear span-to-depth ratios of 1.9 were tested under fully reversed cyclic loads. The primary variables were yield stress of the diagonal reinforcement (60 and 120 ksi [420 and 830 MPa]), target beam shear stress (10 and 15√(f_c^' ) psi [0.83 and 1.25√(f_c^' ) MPa]), length of the secondary (non-diagonal) longitudinal reinforcement, and axial restraint. All specimens had the same nominal concrete compressive strength and beam dimensions. Chord rotation capacities exhibited by the specimens with Grade 120 (830) reinforcement were between 5.1 and 5.6%, less than that of the control specimen with Grade 60 (420) diagonal reinforcement (7.1%). Neither development of secondary reinforcement nor increases in design shear stress affected specimen chord rotation capacity. The axially-restrained specimen with Grade 120 (830) diagonal reinforcement showed the same chord rotation capacity as a similar specimen without axial restraint, but 14% larger strength. In specimens with secondary longitudinal reinforcement extended into the wall (such that the embedment length exceeded the calculated development length), the localization of damage evident along the beam-wall interface in tests of specimens with bars terminating near the wall face was not observed. Although damage was more distributed throughout the beam span, deformation capacity was not increased. Among the specimens, it was shown that the initial stiffness, area of the shear force-chord rotation hysteresis cycles, and residual chord rotation at zero shear force changed in inverse proportion to the diagonal bar yield stress. A database of results from tests of diagonally reinforced coupling beams was compiled and used to evaluate the sensitivity of coupling beam chord rotation capacity to a range of variables. Variables included aspect ratio, reinforcement grade, transverse confinement reinforcement (type, spacing, and ratio), shear stress, and length of secondary (non-diagonal) reinforcement (whether terminated near the beam-wall interface or developed into the wall). An equation was proposed for calculating coupling beam chord rotation capacity as a function of beam clear span-to-height ratio and the ratio of hoop spacing to diagonal bar diameter. Chord rotation capacity was not correlated with other variables. Modifications are also proposed to the stiffness and deformation capacity modeling parameters recommended in ASCE 41-17 and ACI 369.1-17 for diagonally reinforced coupling beams to account for reinforcement grade.
en
openAccess
Copyright held by the author.
Civil engineering
Coupling beam
earthquake resistant
high-strength steel
Reinforced concrete coupling beams
Diagonally-Reinforced Concrete Coupling Beams with High-Strength Steel Bars
Dissertation
oai:kuscholarworks.ku.edu:1808/184162018-01-31T20:07:49Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Lindheimer, Tomas Ernesto
2015-09-07T22:26:26Z
2015-09-07T22:26:26Z
2014-12-31
http://dissertations.umi.com/ku:13674
http://hdl.handle.net/1808/18416
Red Light Running (RLR) is a safety concern for communities nationwide. The Federal Highway Administration (FHWA) reported a total of 676 fatalities in 2009 were due to RLR. The Insurance Institute for Highway Safety (IIHS) reported that more than half of RLR crash fatalities are other than the driver (pedestrians, occupants, etc.). There are many strategies to mitigate RLR violations that fall in the category of engineering, enforcement, or education. This dissertation focused on confirmation lights which are a low-cost countermeasure that enhance enforcement at four-approach intersections. Confirmation lights were deployed at two intersections in Overland Park, Kansas. Traffic was observed at the treatment sites, nearby signalized intersections (spillover), and control sites. Traffic was recorded before deployment, one-month after, and three-months after deployment. A total 14 intersections were recorded during the morning peak hours (7 a.m. to 9 a.m.) and the afternoon peak hours (4 p.m. to 6 p.m.) for a total of 583 hours of traffic video. A test of proportions showed that overall the confirmation lights did not significantly reduce RLR violations. A violation analysis showed that there was a global increase in RLR violations after deployment, showing that other factors were involved in the increase of violations observed. Time into the red analysis showed that the majority of RLR violations occurred within one second into the red. The negative binomial regression model re-affirmed that the confirmation lights were not a significant factor in the RLR violations observed. The model showed that lane volume, presence of a right turn lane, and traffic movement (left or through movement) were significant factors.
en
openAccess
Copyright held by the author.
Civil engineering
Confirmation Lights
Law Enforcement
Red Light Running
Traffic Safety
LONG-TERM EFFECTS OF CONFIRMATION LIGHTS AND FACTORS THAT LEAD TO RED LIGHT RUNNING
Dissertation
oai:kuscholarworks.ku.edu:1808/239632018-01-31T20:07:51Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Jantz, Michael
2017-05-07T20:42:13Z
2017-05-07T20:42:13Z
2014-08-31
http://dissertations.umi.com/ku:13613
http://hdl.handle.net/1808/23963
Recent years have witnessed the widespread adoption of managed programming languages that are designed to execute on virtual machines. Virtual machine architectures provide several powerful software engineering advantages over statically compiled binaries, such as portable program representations, additional safety guarantees, automatic memory and thread management, and dynamic program composition, which have largely driven their success. To support and facilitate the use of these features, virtual machines implement a number of services that adaptively manage and optimize application behavior during execution. Such runtime services often require tradeoffs between efficiency and effectiveness, and different policies can have major implications on the system's performance and energy requirements. In this work, we extensively explore policies for the two runtime services that are most important for achieving performance and energy efficiency: dynamic (or Just-In-Time (JIT)) compilation and memory management. First, we examine the properties of single-tier and multi-tier JIT compilation policies in order to find strategies that realize the best program performance for existing and future machines. Our analysis performs hundreds of experiments with different compiler aggressiveness and optimization levels to evaluate the performance impact of varying if and when methods are compiled. We later investigate the issue of how to optimize program regions to maximize performance in JIT compilation environments. For this study, we conduct a thorough analysis of the behavior of optimization phases in our dynamic compiler, and construct a custom experimental framework to determine the performance limits of phase selection during dynamic compilation. Next, we explore innovative memory management strategies to improve energy efficiency in the memory subsystem. We propose and develop a novel cross-layer approach to memory management that integrates information and analysis in the VM with fine-grained management of memory resources in the operating system. Using custom as well as standard benchmark workloads, we perform detailed evaluation that demonstrates the energy-saving potential of our approach. We implement and evaluate all of our studies using the industry-standard Oracle HotSpot Java Virtual Machine to ensure that our conclusions are supported by widely-used, state-of-the-art runtime technology.
en
openAccess
Copyright held by the author.
Computer science
compiler
dynamic compilation
memory management
optimization
power
virtual machine
Exploring Dynamic Compilation and Cross-Layer Object Management Policies for Managed Language Applications
Dissertation
oai:kuscholarworks.ku.edu:1808/76442020-06-25T19:46:03Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Rea Zanabria, Gino
2011-06-21T16:35:34Z
2011-06-21T16:35:34Z
2011-03-31
http://dissertations.umi.com/ku:11339
http://hdl.handle.net/1808/7644
This thesis presents a hardware design of a coherent demodulator for shaped offset quadrature phase shift keying, telemetry group version (SOQPSK-TG) for use in forward error correction (FEC) applications. Implementation details for data sequence detection, symbol timing synchronization, carrier phase synchronization, and block recovery are described. This decision-directed demodulator is based on maximum likelihood principles, and is efficiently implemented by the soft output Viterbi algorithm (SOVA). The design is intended for use in a field-programmable gate array (FPGA). Simulation results of the demodulator's performance in the additive white Gaussian noise channel are compared with a Matlab reference model that is known to be correct. In addition, hardware-specific parameters are presented. Finally, suggestions for future work and improvements are discussed.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Electrical engineering
Demodulator
Fec
Fpga
Hardware
Implementation
Soqpsk-tg
A Hardware Implementation of a Coherent SOQPSK-TG Demodulator for FEC Applications
Thesis
oai:kuscholarworks.ku.edu:1808/82892020-08-25T14:50:01Zcom_1808_231com_1808_1260col_1808_18153col_1808_7158
Bedell, Frank G.
2011-10-27T19:08:58Z
2011-10-27T19:08:58Z
1906-06
http://hdl.handle.net/1808/8289
In this paper will be given a brief history of the Sudbury Mining district and something of the geology and ore deposits of the same; also, a description of the mining and metallurgical methods used by the Canadian Copper Company in this district. Information on the various subjects treated was obtained partly from published literature by different authors but principally from a personal visit during the summer of 1905 to the country and mines descried.
openAccess
This work is in the public domain according to U.S. copyright law and is available for users to copy, use, and redistribute in part or in whole. No known restrictions apply to the work.
The Sudbury Mining District
Dissertation
oai:kuscholarworks.ku.edu:1808/69602020-08-05T13:00:12Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Bailey, Mark Michael
2010-12-31T04:29:49Z
2010-12-31T04:29:49Z
2010-07-26
http://dissertations.umi.com/ku:11072
http://hdl.handle.net/1808/6960
Fluorinated compounds have many applications in medicine, including oxygen transport, drug delivery vehicles, and contrast agents in medicine due to fluorine's unique chemical and nuclear properties. Fluorinated compounds have been used in microbubble contrast agents for ultrasound imaging, positron sources for PET imaging, and as an imaging probe in 19F MRI. Additionally, fluorinated organic compounds generate a high ionization yield of fluorine in secondary ion mass spectrometry (SIMS), which is gaining recognition as an in vitro cellular imaging technique. This suggests that fluorinated SIMS "chromophores" could be developed for diagnostic imaging that target specific cell markers. The goal of this work has been to develop a fluorinated nanoparticle platform technology that could be used for multiple biomedical imaging techniques, including in vivo and in vitro diagnostic imaging. Fluorinated nanoparticles were synthesized from one of two fluorinated monomers, as well as a hydrophilic monomer and hydrophilic crosslinker to enhance the aqueous colloidal stability of the nanoparticles. Nanoparticles were then characterized to determine their chemical properties, colloidal stability, and suitability for use as a 19F MRI and SIMS contrast agent. Particle sizes were measured using small angle neutron scattering and dynamic light scattering, nuclear magnetic resonance signal was measured using 19F NMR, and chemical functional groups were determined using FTIR. Particle size and structure were also examined using scanning electron microscopy and transmission electron microscopy. The results suggested that nanoparticles are colloidally stable, exhibit a strong 19F NMR signal and a high fluorinated ion yield in SIMS, and contain functional groups that would facilitate conjugation with antibodies or other ligands for targeted nanoparticle delivery to pathological tissues of interest for imaging. Nanoparticles were also developed for bimodal optical fluorescence imaging and SIMS imaging by incorporating a fluorescent functionality within the particles. The fluorescent-fluorinated nanoparticles were conjugated with LABL peptide, which binds to ICAM-1 on the surface of endothelial cells to facilitate T-cell recruitment to sites of inflammation. In vitro cell uptake studies show enhanced binding and uptake of LABL-conjugated fluorescent-fluorinated nanoparticles compared to non-conjugated nanoparticles, suggesting that this technique could be used as a targeting mechanism for cellular imaging. A cell preparation method was also designed for SIMS imaging, which showed great cellular detail. Current work is examining the suitability of fluorinated-fluorescent nanoparticles as SIMS imaging probes for diagnostic imaging using the cell preparation method designed for this work.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Biomedical engineering
Pharmaceutical chemistry
Bioimaging
Fluorine
Nanotechnology
Polymer science
Sims
Fluorinated Nanoparticles: A Novel Technology Platform for Multimodal Biomedical Imaging Applications
Dissertation
oai:kuscholarworks.ku.edu:1808/184302018-01-31T20:07:51Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Lechtenberg, Travis Francis
2015-09-09T02:10:48Z
2015-09-09T02:10:48Z
2015-05-31
http://dissertations.umi.com/ku:13830
http://hdl.handle.net/1808/18430
One goal of this research is to estimate density model corrections using readily available Satellite Laser Ranging (SLR) data, and to demonstrate this approach's validity for additional satellites with similar data sets in the future. The research also aims to utilize previously unused or little used sources of orbit state data to generate corrections to existing density models. These corrections yield estimated density corrections which lead to better drag estimates, improved orbit determination and prediction, as well as an enhanced understanding of density variations in the thermosphere and exosphere. This research primarily focuses on using SLR data. This examination will give a better idea of obtainable improvements in atmospheric density. Consideration will also be given to the effects of varying levels of geomagnetic and solar activity. This work established the validity of using SLR data to estimate atmospheric densities by comparing results for the ANDE Castor satellite to results for the CHAMP and GRACE satellites for the same time periods. The density correction factors and standard deviations comparing the baseline model densities to the derived atmospheric densities are also examined for the ANDE Castor satellite. For the entire family of ANDE satellites, the uncertainty in atmospheric density is established for each arc. The uncertainties are significantly higher at the beginning of the arc for each of the satellites, and the uncertainties also increase as the satellites drop in altitude. Preliminary density values for the Special Purpose Inexpensive Satellite (SPINSat) are also derived.
en
openAccess
Copyright held by the author.
Aerospace engineering
Orbit Determination
Satellite Laser Ranging
Thermospheric Density
Density Model Corrections Derived from Orbit Data to Characterize Upper Atmospheric Density Variations
Dissertation
oai:kuscholarworks.ku.edu:1808/296512019-11-05T23:51:42Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Eshtaiwi, Saleh Mohamed
2019-10-28T22:38:37Z
2019-10-28T22:38:37Z
2019-05-31
http://dissertations.umi.com/ku:16131
http://hdl.handle.net/1808/29651
The worldwide energy demand is growing quickly, with an anticipated growth rate of 48% from 2012 to 2040. Consequently, investments in all forms of renewable energy generation systems have been growing rapidly due to growth rate and climate concerns. Increased use of clean renewable energy resources such as hydropower, wind, solar, geothermal, and biomass is expected to noticeably alleviate many present environmental concerns associated with fossil fuel-based energy generation. In recent years, wind and solar energies have gained the most attention among all other renewable resources. As a result, both have become the target of extensive research and development for dynamic performance optimization, cost reduction, and power reliability assurance. The performance of Photovoltaic (PV) systems is highly affected by environmental and ambient conditions such as irradiance fluctuations and temperature swings. Furthermore, the initial capital cost for establishing the PV infrastructure is very high. Therefore, it is essential that the PV systems always harvest the maximum energy possible by operating at the most efficient operating point, i.e. Maximum Power Point (MPP), to increase conversion efficiency to reach 100% and thus result in lowest cost of captured energy. The dissertation is an effort to develop a new PV conversion system for large scale PV grid-connected systems which provides 99.8% efficacy enhancements compared to conventional systems by balancing voltage mismatches between the PV modules. Hence, it analyzes the theoretical models for three selected DC/DC converters. To accomplish this goal, this work first introduces a new adaptive maximum PV energy extraction technique for PV grid-tied systems. Then, it supplements the proposed technique with a global search approach to distinguish absolute maximum power peaks within multi-local peaks in case of partially shaded PV module conditions. Next, it proposes an adaptive MPP tracking (MPPT) strategy based on the concept of model predictive control (MPC) in conjunction with a new current sensor-less approach to reduce the number of required sensors in the system. Finally, this work proposes a power balancing technique for injection of balanced three-phase power into the grid using a Cascaded H-Bridge (CHB) converter topology which brings together the entire system and results in the final proposed PV power system. The developed grid connected PV solar system is evaluated using simulations under realistic dynamic ambient conditions, partial shading, and fully shading conditions and the obtained results confirm its effectiveness and merits comparted to conventional systems. The resulting PV system offers enhanced reliability by guaranteeing effective system operation under unbalanced phase voltages caused by severe partial shading.
en
openAccess
Copyright held by the author.
Engineering
New Three Phase Photovoltaic Energy Harvesting System for Generation of Balanced Voltages in Presence of Partial Shading, Module Mismatch, and Unequal Maximum Power Points
Dissertation
oai:kuscholarworks.ku.edu:1808/241632023-03-04T07:05:46Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Lindsey, Theodore S.
2017-05-15T01:40:52Z
2017-05-15T01:40:52Z
2016-12-31
http://dissertations.umi.com/ku:15002
http://hdl.handle.net/1808/24163
IRIM (Interesting Rule Induction Module) is a rule induction system designed to induce particularly strong, simple rule sets. Additionally, IRIM does not require prior discretization of numerical attribute values. IRIM does not necessarily produce consistent rules that fully describe the target concepts, however, the rules induced by IRIM often lead to novel revelations of hidden relationships in a dataset. In this paper, we attempt to extend the IRIM system to be able to handle missing attribute values (in particular, lost and do-not-care attribute values) more thoroughly than ignoring the cases that they belong to. Further, we include an implementation of IRIM in the modern programming language Python that has been written for easy inclusion in within a Python data mining package or library. The provided implementation makes use of the Pandas module which is built on top of a C back end for quick performance relative to the performance normally found with Python.
en
openAccess
Copyright held by the author.
Computer science
Data mining
Data Science
IRIM
Rule Induction
Interesting Rule Induction Module: Adding Support for Unknown Attribute Values
Thesis
oai:kuscholarworks.ku.edu:1808/40492018-01-31T20:08:15Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Petri, Brad
2008-08-05T04:11:31Z
2008-08-05T04:11:31Z
2008-05-15
http://dissertations.umi.com/ku:2572
http://hdl.handle.net/1808/4049
With the increasing focus on welded bridge members resulting in crack initiation and propagation, there is a large demand for creative solutions. One of these solutions includes the application of composite doublers over the critical weld. In order to establish an effective finite element analysis, models were created using ABAQUS (2007). Models were created to properly represent physical testing being done parallel to this study. These models represented the control specimen, consisting of a welded coverplate, and several composite doubler arrangements. The first composite doubler analyzed consisted of the smooth shape which was designed for easy transfer of stresses between composite and steel material. The next models used a rectilinear composite shape, which was designed to simplify the construction of these doublers, these models varied by the bond length on the top plate. Finally an analysis was conducted to evaluate the effect of the Young's modulus of the composite material. The results from each model were then compared and the most effective arrangement was stated.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Civil engineering
FINITE ELEMENT ANALYSIS OF STEEL WELDED COVERPLATE INCLUDING COMPOSITE DOUBLERS
Thesis
oai:kuscholarworks.ku.edu:1808/40452018-01-31T20:08:06Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Nunez, Daniel
2008-08-05T03:49:51Z
2008-08-05T03:49:51Z
2008-05-21
http://dissertations.umi.com/ku:2478
http://hdl.handle.net/1808/4045
This thesis presents an infrastructure for computations of the J-integral for mode I linear elastic fracture mechanics in h,p,k mathematical and computational framework using finite element formulations based on the Galerkin method with weak form and the least squares process. Since the differential operators in this case are self-adjoint, both the Galerkin method with weak form and the least square processes yield unconditionally stable computational processes. The use of h,p,k frameworks permits higher order global differentiability approximations in the finite element processes which are necessitated by physics, calculus of continuous and differentiable functions and higher order global differentiability features of the theoretical solutions. The significant aspect of this research is that with the proposed methodology very accurate J-integral computations are possible for all paths including those in very close proximity of the crack without use of special crack tip or quarter point elements at the crack tip. A center crack panel under isotropic homogeneous plane strain linear elastic behavior, subjected to uniaxial tension (mode I) is used as model problem for all numerical studies. The investigations presented in this thesis are summarized here: (i) J-integral expression is derived and it is shown that its path independence requires the governing differential equations (GDEs) to be satisfied in the numerical process used for its computations (ii) It has been shown that the J-integral path must be continuous and differentiable (iii) The integrand in the J-integral must be continuous along the path as well as normal to the path (iv) Influence of the higher order global differentiability approximations on the accuracy of the J-integral is demonstrated (v) Stress intensity correction factors are computed and compared with published data. The work presented here is a straight-forward finite element methodology in h,p,k framework is presented in which all mathematical requirements for J-integral computations are satisfied in the computational process and as a result very accurate computations of J-integral are possible for any path surrounding the crack tip without using any special treatments. Both the Galerkin method with weak form and the least square processes perform equally well.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Aerospace engineering
Mechanical engineering
J-integral
Galerkin method with weak form
Least squares processes
Linear elastic fracture mechanics
J-integral Computations for Linear Elastic Fracture Mechanics in h,p,k Mathematical and Computational Framework
Thesis
oai:kuscholarworks.ku.edu:1808/252802017-12-08T21:43:44Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Nystrom, Clifford William
2017-11-08T16:50:37Z
2017-11-08T16:50:37Z
1930
http://hdl.handle.net/1808/25280
openAccess
This work is in the public domain and is available for users to copy, use, and redistribute in part or in whole. No known restrictions apply to the work.
Some recent developments in long distance telephone cable construction
Thesis
oai:kuscholarworks.ku.edu:1808/276132020-10-13T20:38:48Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Craig, Jordan
2019-01-02T20:40:47Z
2019-01-02T20:40:47Z
2018-12-31
http://dissertations.umi.com/ku:16195
http://hdl.handle.net/1808/27613
https://orcid.org/0000-0003-2350-6648
SUMMARY: The purpose of this study was to investigate how the relationships between upper body (trunk) and lower body (feet) motion are affected by multiple sclerosis (MS), and how these relationships can be used to characterize gait stability in persons with MS (PwMS). In Aim 1, we determined how segment relationships are affected by changing walking speed and sensory input in PwMS compared to healthy controls. PwMS and healthy age-matched controls walked on a treadmill at a range of speeds while wireless inertial sensors measured foot and trunk acceleration. The ratio of acceleration variability between upper and lower body segments, referred to as the gait stability index (GSI), was used to represent the segment coordination relationship during gait and was compared across all walking trials and groups. In Aim 2, we determined how the GSI was related to pathophysiology, clinical disability, and mobility scales in PwMS. Physiological deficits in PwMS were measured through postural response latencies and somatosensation thresholds. Clinical disability and mobility were measured by self-report fall history and clinical questionnaires. In Aim 3, GSI cutoff values and amount of overground walking needed to separate MS fallers from MS non-fallers were determined using data collected continuous 4-minutes of walking over a 10-meter walkway in the laboratory. RELEVANCE: Falls are a leading cause of non-fatal injury and a significant health problem for persons with multiple sclerosis. The current study utilizes a novel technique to examine how critical relationships between motion of upper and lower body segments respond under normal and challenging conditions, and how the maintenance of these relationships is tied to instability and fall risk. Investigation of these segmental relationships during walking is significant to developing gait assessment methods for any population to monitor stability in daily life, identify risk of future falls, and longitudinally track disease progression or treatment efficacy.
en
openAccess
Copyright held by the author.
Biomechanics
Accelerometry
Assessments
Falls
Gait
Multiple sclerosis
Quantifying gait stability based on body segment coordination relationships measured with wireless sensors
Dissertation
oai:kuscholarworks.ku.edu:1808/114672020-09-29T13:32:17Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Jeong, Jong Cheol
2013-07-14T15:47:07Z
2013-07-14T15:47:07Z
2013-05-31
http://dissertations.umi.com/ku:12808
http://hdl.handle.net/1808/11467
https://orcid.org/0000-0002-5024-2927
1.2 billion users in facebook, 17 million articles in Wikipedia, and 190 million tweets per day have demanded significant increase of information processing through Internet in recent years. Similarly life sciences and bioinformatics also have faced issues of processing Big data due to the explosion of publicly available genomic information resulted from the Human Genome Project (HGP) and the increasing usage of high throughput technology. HGP was completed in 2003 and resulted in identifying 20,000-25,000 genes in human DNA and determining the sequences of three billion human base pairs. The information requires huge amount of data storage and becomes difficult to process using on-hand database management tools or traditional data processing applications. This thesis introduces new method, Biological and Statistical Mean (BSM) score to calculate functional similarity between gene products (GPs) that can help to extract biologically relevant and statistically robust information from large-scale biomedical, genomic and proteomic data sources. BSM score is defined by 16 different scoring matrices derived from principles of multi-view learning in machine learning algorithm and five different databases including Gene Ontology, UniProt, SCOP, CATH, and KUPS. The proposed method also shows how diverse databases and principles in machine learning theory can be integrated into a simple scoring function, and how the simple concept can give significant impact on the studies in biomedical and human life sciences. The comprehensive evaluations and performance comparisons with other conventional methods show that BSM score clearly outperforms other methods in terms of sensitivity of clustering similarity functional groups and coverage of identifying related genes. As a part of potential applications handling large amount of diverse data sources in medical domain, this thesis introduces similarity-based drug target identification and disease networks using BSM scores. Application of BSM score is freely available through http://www.ittc.ku.edu/chenlab/goal/
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Bioinformatics
Computer science
Information science
Disease relation
Drug target identification
Functional similarity
Gene ontology
Machine learning
Semantic distance
New Methodology for Measuring Semantic Functional Similarity Based on Bidirectional Integration
Dissertation
oai:kuscholarworks.ku.edu:1808/263572018-12-13T18:55:23Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Liu, Siyan
2018-04-20T22:47:13Z
2018-04-20T22:47:13Z
2017-12-31
http://dissertations.umi.com/ku:15713
http://hdl.handle.net/1808/26357
Traditional network models use simplified pore geometries to simulate multiphase flow using semi-analytical correlation-based approaches. In this work, we aim at improving these models by (I) extending the numerical methodologies to account for pore geometries with convex polygon cross sections and (II) utilizing Artificial Neural Networks (ANN) to predict flow-related properties. Specifically, we simulate fluid displacement sequences during a drainage process in bundles of capillary tubes with randomly generated convex polygon cross-sections. In the beginning, we assume that capillary tubes are fully saturated with water and that they are strongly water-wet. Then, oil is injected to displace water during the primary drainage process. The model calculates threshold capillary pressures for all randomly generated geometries using Mayer-Stowe-Princen (MS-P) method and the minimization of Helmholtz free energy for every pore-scale displacement event. Knowing pore fluid occupancies, we calculate saturations, phase conductances, and two-phase capillary pressure and relative permeability curves. These parameters are then used as input to train an ANN. ANN theories and related applications have been significantly promoted due to the fast increasing performance of computer hardware and inheratively complicated nature of some research areas. Various Artificial Intelligence (AI) applications have been developed specifically for the oil and gas industry such as AI assisted history matching, oil field production and development predictions, and reservoir characterization. The objective of this study is to develop an ANN training and predicting workflow that can be integrated with the conventional pore network modeling techniques. This hybrid model is computationally much faster which is beneficial for large-scale simulations in 3D. It could also be used to improve prediction of flow-related properties in similar rock types. Specifically, we are interested in the training of ANNs to predict threshold capillary pressures and multi-phase flowrates as a function of cross-sectional shapes and wettabilities given for each capillary tube of the bundle. To do so, we have generated multi-phase flow properties for two large datasets consisting of 40,000 and 60,000 capillary tubes each. The predictive capability of the ANN is gauged by performing some quality control steps including blind test validations. We present the results primarily by demonstrating the calculated errors and deviations for any randomly generated bundles of capillary tubes from the aforementioned dataset. We show that generating high-quality training dataset is critical to improving model’s predictive capabilities for a wide range of pore geometries, e.g., shape factors and elongations. Additionally, we demonstrate that feature selection and preprocessing of the input data could significantly impact ANN’s predictions. We analyze a wide range of structures for the ANN models. The Multi-layer perceptron (MLP) Neural Network with three hidden layers is adequate for dealing with the complexity and non-linearity of most of our studied cases. This model is approximately an order of magnitude faster than conventional direct calculations using a personal desktop computer with four cores CPU. Such improvement in the speed of calculations becomes extremely important when dealing with larger models, adding more dimensionality, and/or introducing pore connectivity in 3D.
en
openAccess
Copyright held by the author.
Petroleum engineering
artificial neural network
capillary pressure
machine learning
multi-layer perceptron
pore network modeling
relative permeability
Prediction of Capillary Pressure and Relative Permeability Curves using Conventional Pore-scale Displacements and Artificial Neural Networks
Thesis
oai:kuscholarworks.ku.edu:1808/145982018-01-31T20:08:05Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Zakharov, Mikhail
2014-07-05T18:49:08Z
2014-07-05T18:49:08Z
2014-05-31
http://dissertations.umi.com/ku:13233
http://hdl.handle.net/1808/14598
This thesis presents the design, analysis and test results of a 1.445 GHz Frequency-Modulated Continuous Wave (FMCW) collision-avoidance radar for Unmanned Aircraft Systems (UASs). This radar system is being developed by the department of Electrical Engineering (EE) in coordination with the Aerospace Engineering (AE) department and is intended to provide situational awareness for a 40% Yak-54 model aircraft by providing range, radial velocity and angle-of-arrival (AoA) information for nearby targets. A target's range and Doppler is determined by employing a two-dimensional (2-D) Fast Fourier Transform (FFT) on the received signal which maps the target to a specific range-Doppler bin. An array of receiving antennas is used to determine a target's elevation and azimuth angles by exploiting the received signal's phase difference at each individual antenna.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Electrical engineering
Fmcw
Multi-channel
Radar
Uas
Designing a Multichannel Sense-and-Avoid Radar for Small UASs
Thesis
oai:kuscholarworks.ku.edu:1808/297092019-11-05T23:51:42Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Zhou, Chenqi
2019-11-01T01:13:16Z
2019-11-01T01:13:16Z
2019-08-31
http://dissertations.umi.com/ku:16671
http://hdl.handle.net/1808/29709
The Kansas Department of Transportation (KDOT)'s current design practice is to align cross-frames parallel to the skew angle to avoid problems associated with fit-up during erection. The American Association of State Highway and Transportation Officials (AASHTO) provisions for bridges with skew angle greater than 20 degrees are based on the assumption that cross-frames are oriented perpendicular to the girder line. There is a potentially significant discrepancy between assumptions implicit in the AASHTO Specifications and bridges that are designed with cross-frames placed parallel to the skew for skew angles between 20 and 40 degrees. An analytical approach was chosen to study the effects of cross-frame orientation, spacing, skew angle, and connection design upon flange stresses, bridge stability, and cross-frame stresses.
en
openAccess
Copyright held by the author.
Civil engineering
brace
connection design
construction
cross-frame
skewed bridge
stability design
Brace Effectiveness of Cross-frame Layout and Connection Design on Skewed Steel Bridges During Construction
Dissertation
oai:kuscholarworks.ku.edu:1808/194252018-01-31T20:07:50Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Barnds, Annaria
2016-01-01T22:34:24Z
2016-01-01T22:34:24Z
2015-05-31
http://dissertations.umi.com/ku:14035
http://hdl.handle.net/1808/19425
The long term objective of this research is to identify quantitative biomechanical parameters of postural instability in patients with Parkinson’s disease (PD) that can in turn be used to assess fall risk. Currently, clinical assessments in PD are not sufficiently sensitive to predict fall risk, making a history of falls to be the best predictor of a future fall. Identifying biomechanical measures to predict risk of falls in PD would provide a quantitative justification to implement fall-reducing therapies prior to a first fall and help prevent the associated debilitating fractures or even morbidity. While past biomechanical studies have shown the presence of balance deficits in PD patients, which often include a broad spectrum of disease stages, compared to healthy controls (HC), no studies have assessed whether such parameters can distinguish the onset of postural instability prior to clinical presentation, and if such parameters persist following clinical presentation of postural instability. Toward this end this study had three goals: • Determine if biomechanical assessment of a quasi-static task, postural sway, could provide preclinical indication of postural instability in PD. • Define a mathematical model (based on principal component analysis, PCA) with biomechanical and clinical measures as inputs to quantitatively score earlier postural instability presence and progression in PD. • Investigate if biomechanical assessment of a dynamic task, gait initiation, could provide preclinical indication of postural instability in PD. Specific Aim 1 determined that some biomechanical postural sway variables showed evidence of preclinical postural instability and increased with PD progression. This aim distinguished mild PD (Hoehn and Yahr stage (H&Y) 2, without postural deficits) compared to HC suggesting preclinical indication of postural instability, and confirmed these parameters persisted in moderate PD (H&Y 3, with postural deficits). Specifically, trajectory, variation, and peak measures of the center of pressure (COP) during postural sway showed significant differences (p < .05) in mild PD compared to healthy controls, and these differences persisted in moderate PD. Schwab and England clinical score best correlated with the COP biomechanical measures. These results suggest that postural sway COP measures may provide preclinical indication of balance deficits in PD and increase with clinical PD progression. Specific Aim 2 defined a PCA model based on biomechanical measures of postural sway and clinical measures in mild PD, moderate PD, and HC. PCA modeling based on a correlation matrix structure identified both biomechanical and clinical measures as the primary drivers of variation in the data set. Further, a PCA model based on these selected parameters was able to significantly differentiate (p < .05) all 3 groups, suggesting PCA scores may help with preclinical indication of postural instability (mild PD versus HC) and could be sensitive to clinical disease progression (mild PD versus moderate PD and moderate PD versus HC). AP sway path length and a velocity parameter were the 2 primary measures that explained the variability in the data set, suggesting further investigation of these parameters and mathematical models for scoring postural instability progression is warranted. Specific Aim 3 determined that a velocity measure from biomechanical assessment of gait initiation (peak COP velocity towards the swing foot during locomotion) showed evidence of preclinical postural instability in PD. Because balance is a complex task, having a better understanding of both quasi-static (postural sway) and dynamic (gait initiation) tasks can provide further insight about balance deficits resulting from PD. Several temporal and kinematic parameters changed with increasing disease progression, with significant difference in moderate PD versus HC, but missed significance in mild PD compared to HC. Total Unified Parkinson’s Disease Rating Scale (UPDRS) and Pull Test clinical scores best correlated with the biomechanical measures of the gait initiation response. These results suggest dynamic biomechanical assessment may provide additional information in quantifying preclinical postural instability and progression in PD. In summary, reducing fall risk in PD is a high priority effort to maintain quality of life by allowing continued independence and safe mobility. Since no effective screening method exists to measure fall risk, our team is developing a multi-factorial method to detect postural instability through clinical balance assessment, and in doing so, provide the justification for implementing fall reducing therapies before potentially debilitating falls begin.
en
openAccess
Copyright held by the author.
Biomechanics
Mechanical engineering
Biomedical engineering
balance
biomechanics
motor control
Parkinson's disease
postural instability
BIOMECHANICAL MARKERS AS INDICATORS OF POSTURAL INSTABILITY PROGRESSION IN PARKINSON'S DISEASE
Dissertation
oai:kuscholarworks.ku.edu:1808/101492018-01-31T20:08:01Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Adany, Peter
2012-09-28T12:04:20Z
2012-09-28T12:04:20Z
2012-08-31
http://dissertations.umi.com/ku:12316
http://hdl.handle.net/1808/10149
To date, nonlinear spectroscopy has been considered an expensive technique and confined mostly to experimental laboratory settings. Over recent years, optical-fiber lasers that are highly reliable, simple to operate and relatively inexpensive have become commercially available, removing one of the major obstacles to widespread utilization of nonlinear optical measurement in biochemistry. However, fiber lasers generally offer relatively low output power compared to lasers traditionally used for nonlinear spectroscopy, and much more careful design is necessary to meet the excitation power thresholds for nonlinear signal generation. On the other hand, reducing the excitation intensity provides a much more suitable level of user-safety, minimizes damage to biological samples and reduces interference with intrinsic chemical processes. Compared to traditional spectroscopy systems, the complexity of nonlinear spectroscopy and imaging instruments must be drastically reduced for them to become practical. A nonlinear spectroscopy tool based on a single fiber laser, with electrically controlled wavelength-tuning and spectral resolution enhanced by a pulse shaping technique, will efficiently produce optical excitation that allows quantitative measurement of important nonlinear optical properties of materials. The work represented here encompasses the theory and design of a nonlinear spectroscopy and imaging system of the simplest architecture possible, while solving the difficult underlying design challenges. With this goal, the following report introduces the theories of nonlinear optical propagation relevant to the design of a wavelength tunable system for nonlinear spectroscopy applications, specifically Coherent Anti-Stokes Spectroscopy (CARS) and Förster Resonance Energy Transfer (FRET). It includes a detailed study of nonlinear propagation of optical solitons using various analysis techniques. A solution of the generalized nonlinear Schrödinger equation using the split-step Fourier method is demonstrated and investigation of optical soliton propagation in fibers is carried out. Other numerical methods, such as the finite difference time domain approach and spectral-split step Fourier methods are also described and compared. Numerical results are contrasted with various measurements of wavelength shifted solitons. Both CARS and FRET test-bed designs and experiments are presented, representing two valuable biochemical measurement applications. Two-photon excitation experiments with a simplified calibration process for quantitative FRET measurement were conducted on calmodulin proteins modified with fluorescent dyes, as well as modified enhanced green fluorescent protein. The resulting new FRET efficiency measurements showed agreement with those of alternative techniques which are slower and can involve destruction of the sample. In the second major application of the nonlinear spectroscopy system, CARS measurement with enhanced spectral resolution was conducted on cyclohexane as well as on samples of mouse brain tissue containing lipids with Raman resonances. The measurements of cyclohexane verified the ability of the system to precisely determine its Raman resonances, thus providing a benchmark within a similar spectral range for biological materials which have weaker Raman signal responses. The improvement of spectral resolution (resonance frequency selectivity), was also demonstrated by measuring the closely-spaced resonances of cyclohexane. Finally, CARS measurements were also made on samples of mouse brain tissue which has a lipids-based Raman signature. The CARS spectrum of the lipid resonances matched well with other cited studies. The imaging of mouse brain tissue with Raman resonance contrast was also partially achieved, but it was hindered by low signal to noise ratio and limitations of the control hardware that led to some dropout of the CARS signal due to power coupling fluctuations. Nevertheless, these difficulties can be straightforwardly addressed by refinement of the wavelength tuning electronics. In conclusion, it is hoped that these efforts will lead to greater accessibility and use of CARS, FRET and other nonlinear spectral measurement instruments, in line with the promising advances in optics and laser technology.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Electrical engineering
Optics
Coherent anti-stokes raman spectroscopy
Förster resonance energy transfer
Nonlinear Schrödinger equation
Optical soliton
Spectral imaging microscopy
Split-step fourier method
Fiber Laser Based Nonlinear Spectroscopy
Dissertation
oai:kuscholarworks.ku.edu:1808/246332017-12-08T21:43:43Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Fiedler, George Joseph
2017-06-26T21:11:44Z
2017-06-26T21:11:44Z
1932
http://hdl.handle.net/1808/24633
openAccess
This work is in the public domain and is available for users to copy, use, and redistribute in part or in whole. No known restrictions apply to the work.
Railway electrification and its application to the Chicago and Illinois Midland Railroad
Thesis
oai:kuscholarworks.ku.edu:1808/239212018-01-31T20:07:52Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Narasimman, Anirudh
2017-05-07T16:18:18Z
2017-05-07T16:18:18Z
2016-08-31
http://dissertations.umi.com/ku:14750
http://hdl.handle.net/1808/23921
As one of the world’s most famous online social networks (OSN), Twitter now has 320 million monthly active users. Accompanying the large user group and abundant personal information, users increasingly realize the vulnerability of tweets and have reservations of showing certain tweets to different follower groups, such as colleagues, friends and other followers. However, Twitter does not offer enough privacy protection or access control functions. Users can just set an account as protected, which results in only the user’s followers seeing the tweet. The protected tweet does not appear in the public domain, third party sites and search engines cannot access the tweet. However, a protected account cannot distinguish between different follower groups or users who use multiple accounts. To serve the demand of the user so that they can restrict the access of each tweet to certain follower groups, we propose a browser plug-in system, which utilizes CP-ABE (Ciphertext Policy Attribute based encryption), allowing the user to select followers based on predefined attributes. Through simple installation and pre-setting, the user can encrypt and decrypt tweets conveniently and can avoid the fear of information leakage.
en
openAccess
Copyright held by the author.
Computer science
Private Tweets
Arcana: Private tweets on a public microblog platform
Thesis
oai:kuscholarworks.ku.edu:1808/147712020-10-19T13:57:08Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Broaddus, Tamathy Swift
2014-07-16T16:45:46Z
2014-07-16T16:45:46Z
2013-12-31
http://dissertations.umi.com/ku:13127
http://hdl.handle.net/1808/14771
Objectives of the Study The objective of this mixed methods case study is two-fold. First, it explores corporate learning using the theory of organizational knowledge creation and one US based corporation to determine the theory's relevance to American firms. Second, it seeks to understand how social practices and leadership behaviors affect employee knowledge or "true beliefs" and thus the implications to the firm's knowledge creation and ultimately, its competitive advantage. Ikujiro Nonaka's theory of organizational knowledge creation is used as the framework to examine the extent to which internal factors affect knowledge creation at the organizational and employee levels. The research addresses two questions regarding Nonaka's theory: 1) it assesses the theory in a US corporation with a relatively homogenous population to determine the validity of the theory that was developed outside the US and 2) it examines to what extent internal factors such as social practices and leadership behaviors affect the organizational knowledge creation process. In addition, consequences from events external to the firm are assessed to determine their impact on knowledge creation and corporate learning. Summary The study used knowledge creation theory to understand how internal behaviors and external events affected corporate learning and competitive advantage. Given that knowledge is only useful in its context, the introduction described the origins of the firm and impact of the Internet. The literature review provided the historical context for organizational culture in US firms, the growth of learning organizations and it summarized organizational knowledge creation theory. Social practices and leadership behaviors were explored in relation to a variety of topics. The research used quantitative and qualitative data that included survey data and qualitative data collected from semi-structured interviews, direct observation, internal documents, and secondary sources. The variety of sources aided the attempt to identify robust answers to the broad research questions raised in the study. Conclusions The interviews and direct observations at the firm reveal that organizational knowledge creation is not evident in this US corporation, primarily due to the narrow way in which knowledge is perceived and leadership behaviors that fail to consistently empower subordinates in the hierarchical management model. The cultural beliefs that preclude knowledge creation were also observed to thwart corporate learning. Several social practices and leadership behaviors appear to influence employee beliefs and thus corporate learning including communication transparency, decision-making and accountability, and strategic responses to external "random" events in digital communication. Shortcomings in these areas appear to have related and unintended consequences of diminished trust, lack of confidence, and risk aversion that can jeopardize the firm's competitive advantage.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Adult education
Organizational behavior
Management
Corporate learning
Leadership
Organizational development
Organizational knowledge creation
Organizational learning
Strategic learning
Confronting the Black Swan: A Case Study of Corporate Learning
Thesis
oai:kuscholarworks.ku.edu:1808/98362018-01-31T20:08:01Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Shelley, John Edwin
2012-06-03T16:54:10Z
2012-06-03T16:54:10Z
2012-05-31
http://dissertations.umi.com/ku:11994
http://hdl.handle.net/1808/9836
Natural channel design in river engineering is the philosophy and practice of designing stream channels by copying or mimicking the geomorphology of stable, self-formed streams. This dissertation presents methods and equations for incorporating the principals of natural channel design into river and stream engineering in Kansas. Data from 123 reference reaches in Kansas are used to develop these methods and equations. An analysis of 46 gaged reference reaches indicates that the return period of bankfull flow (annual maximum series), ranges from 1.01 to 1.7 years, with an average of 1.2 years. This is significantly lower than the 2-year flow commonly used by engineers in naturalistic river designs. An equation is developed that predicts the 1.2-year flow as a function of watershed drainage area, mean annual precipitation, and the length of the longest flow path in the watershed. This equation is developed using data from 67 gaged streams with drainage areas less than 30 sq miles. Geomorphic measurements from the reference reaches are used to verify previously published relationships between bankfull discharge and bankfull width for streams with sand and gravel beds. A new relationship is developed demonstrating the relationship between bankfull discharge and bankfull width for streams with beds of cohesive clay. Equations are provided to predict the average meander wavelength from the bankfull width, and the pool depth from the depth at the adjacent riffle. Three stream design methods are presented: the Kansas Analytical Method (KAM), the Analytical Reference Reach Method (ARRM), and the Scaled Geomorphic Method (SGM). All three methods are based on natural stream processes and geomorphology. All three methods incorporate the Manning equation for flow resistance and the Meyer-Peter and Muller equation for sediment transport but differ in their use of geomorphic measurements from reference reaches. KAM uses a hydraulic geometry width equation which was developed from many reference reaches. ARRM uses the sinuosity, pool-depth ratio, and meander-width ratio from a single reference reach. SGM calculates a scaling factor that can be used to copy and scale additional cross-sections (pools, runs, and glides, as well as riffles) and planform features from the reference reach. The development of KAM and ARRM is presented in previously published reports. This dissertation presents the development of SGM in detail. KAM, ARRM, and SGM make a common assumption that the median size of sediment in the channel bed is an adequate surrogate for the entire gradation of bed sediments. The reasonableness of this assumption is verified by calculating the bankfull sediment transport capacity for seven ARRM designs. It is found that a channel designed for equilibrium transport of the median sediment size is reasonably designed for transport of the entire gradation of sediment sizes. The exception is when the median sediment size found on the bed is among the largest that are mobile at bankfull flow. These geomorphic relationships, equations, and design methods combine traditional hydraulic engineering and fluvial geomorphology in unique ways to provide practical tools to stream designers in Kansas.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Civil engineering
Geomorphology
Water resource management
Fluvial geomorphology
Natural channel design
River engineering
River restoration
Stream realignment
Geomorphic Equations and Methods for Natural Channel Design
Dissertation
oai:kuscholarworks.ku.edu:1808/304802021-03-05T16:53:56Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Ibrahim, Eman Khalid
2020-06-14T21:10:29Z
2020-06-14T21:10:29Z
2019-12-31
http://dissertations.umi.com/ku:16832
http://hdl.handle.net/1808/30480
https://orcid.org/0000-0003-3243-325X
ABSTRACT The effects of crack-reducing technologies and supplementary cementitious materials on plastic settlement cracking and the durability of concrete subjected to freezing and thawing were evaluated. The study of settlement cracking included 86 concrete mixtures containing internal curing (IC), a shrinkage reducing admixture (SRA), optimized and non-optimized aggregate gradations, or the supplementary cementitious materials (SCMs) slag cement and silica fume. Some concrete mixtures contained combinations of these technologies, such as supplementary cementitious materials and internal curing. Both crack length and width were measured. The study of durability included 28 concrete mixtures, divided into three programs. Program 1 involved concrete containing different dosage rates of one of two shrinkage reducing admixtures. Program 2 involved concrete containing different volume replacements of Class F and Class C fly ash and different combinations of a rheology-modifying admixture (RMA) with and without Class C fly. Program 3 involved concrete containing different dosage rates of one of two shrinkage compensating admixtures, one based on MgO that also incorporated a shrinkage reducing admixture and one based on CaO. The study evaluated the effect of the technologies and materials on freeze-thaw durability, based on ASTM C666 Procedure B, scaling resistance, based on a modified version of Canadian Test BNQ NQ 2621-900 Annex B, and characteristics of the air-void system, obtained following ASTM C457. The research also examined the correlation between air-void characteristics, compressive strength, freeze-thaw durability, and scaling resistance for the mixtures. All mixtures experienced increased settlement cracking as slump increased; the increase, however, was very low for the concrete containing both slag cement and silica fume, with or without internal curing. All crack reducing technologies and supplementary cementitious materials tested resulted in a reduction in settlement cracking at all slumps compared to mixtures without these technologies and materials. The use of a non-optimized aggregate gradation increased settlement cracking compared to mixtures with an optimized gradation. The combination of slag cement and silica fume in concrete provided a greater reduction in settlement cracking than slag cement alone. In terms of durability, mixtures with an average air-void spacing factor of 0.007 in. (0.18 mm) or less performed well in the freeze-thaw test. Mixtures with an average air-void spacing factor of 0.007 in. (0.18 mm) or less and a compressive strength greater than 4000 psi (27.6 MPa) performed well in the scaling test. In terms of specific performance, one SRA had no effect on freeze-thaw durability, while the other caused reduced durability. Concrete with either SRA exhibited a reduction in scaling resistance. Mixtures containing Class F fly ash, RMA, or Class C fly ash in conjunction with RMA at all dosages studied performed well in the freeze-thaw test if the air-void spacing factor was 0.007 in. (0.18 mm) or less. Class F or Class C fly ash alone had no effect on scaling resistance when the concrete had an air-void spacing factor of 0.0071 in. (0.18 mm) or less. The RMA without and with Class C fly ash resulted in reduced scaling resistance. This reduction was in all cases associated with a concrete compressive strength below 4000 psi (27.6 MPa). An SCA based on CaO had no effect on the freeze-thaw durability at the dosage used in this study. The SCA based on MgO resulted in lower freeze-thaw durability, but only in mixtures that had increased air-void spacing; the increased air-void spacing may have been due to the shrinkage reducing admixture incorporated in the admixture, which can reduce the stability of the air-void system. With the exception of one mixture with high air-void spacing factor [0.0096 in. (0.24 mm)], the two SCAs had no effect on scaling resistance at all dosages used in this study. All mixtures exhibited a lower air content in the hardened concrete than in the plastic concrete. This reduction in air content was significantly greater for mixtures containing high dosages of SRAs or the RMA.
en
openAccess
Copyright held by the author.
Engineering
Civil engineering
air-void characteristics
freeze-thaw durability
Internal curing
scaling resistance
settlement cracking
Structural Engineering
EFFECT OF CRACK-REDUCING TECHNOLOGIES AND SUPPLEMENTARY CEMENTITIOUS MATERIALS ON SETTLEMENT CRACKING OF PLASTIC CONCRETE AND DURABILITY PERFORMANCE OF HARDENED CONCRETE
Dissertation
oai:kuscholarworks.ku.edu:1808/258962018-02-02T09:01:22Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Mullick, Sunayan
2018-02-01T13:58:41Z
2018-02-01T13:58:41Z
2017-05-31
http://dissertations.umi.com/ku:15375
http://hdl.handle.net/1808/25896
A major contributor to the overall noise of an aircraft is jet noise – the noise generated by the gases exiting the exhaust nozzle of a jet engine. One approach to mitigate jet noise is through the implementation of chevron nozzles. In the present context, first, a baseline axisymmetric separate-flow nozzle, termed the 3BB model, with an external plug having a bypass ratio of 5 is analyzed. The specifications of this nozzle are taken from an acoustic study carried out at the NASA John H. Glenn Research Center. Then, various chevron configurations are added to the core and fan nozzles to produce three chevron nozzles. Of these, two are presented as modified versions of the conventional chevron nozzle and form the essence of this work. The third chevron nozzle represents the conventional chevron nozzle in use today. For all the nozzles considered in this study, the flow conditions used represent the takeoff environment of a contemporary subsonic aircraft. The fan nozzle total pressure is set to 1.8 atm while the core nozzle total pressure is 1.65 atm. The total temperature inside the fan nozzle is set to 333.3 K while the core nozzle has a total temperature of 833.3 K. The freestream conditions are given as: static pressure = 0.98 atm, total pressure = 1.04 atm, total temperature = 298.8 K and Mach number = 0.28. For the three chevron nozzles, the core and fan nozzles have 12 chevrons each. Each chevron extends over a sector of 30 degrees of the circumference. To carry out the study presented herein, first, computer-aided design (CAD) models of the four nozzles are created. These models are then used to carry out computational fluid dynamics (CFD) simulations with the conditions stated above. The CFD simulations are performed on STAR-CCM+. The results of the simulations carried out for the baseline nozzle are compared with existing experimental and numerical data to validate the use of STAR-CCM+ as a tool for studying jet flows. Once this step is complete, numerical simulations are carried out for the three chevron nozzles. The results from these are compared with those obtained for the baseline nozzle. The turbulent kinetic energy (TKE) and the mean axial velocity are the two main parameters that represent mixing enhancement and are focused on in this work. Since the TKE levels for a given nozzle are directly linked to the jet noise generated, the TKE is an important indication of the jet noise produced by a given nozzle. Other jet mixing parameters such as the centerline total temperature decay and the centerline velocity of the jet flow exiting each nozzle are also analyzed. A 2-D axisymmetric grid is produced for the 3BB nozzle while a 3-D mesh is generated for each of the chevron nozzles. To reduce the computation cost, only a 30° sector of the chevron nozzles is modeled. Since the Shear Stress Transport (SST) k-ω turbulence model has been widely used in several aerospace applications, it is chosen for all simulations here as well. The numerical analysis shows that STAR-CCM+ can successfully be used for the study of jet flows. Although some shortcomings do exist, the simulations provide a reasonable understanding of jet flows. Of the three chevron nozzles studied, the simulations demonstrate that in comparison to the baseline nozzle, all three chevron nozzles register peak values of the turbulent kinetic energy that are lower than that observed for the 3BB nozzle. The regions of highest turbulence also appear further upstream for the chevron nozzles. Compared to the conventional chevron nozzle, the two parametric designs presented in this work show a potential reduction in the peak values of the turbulent kinetic energy in their respective flows. A slight reduction in the mean axial velocities is also observed for these nozzles. Further, a close inspection of the turbulent flowfield of one of the parametric designs shows that the highest intensity turbulence in the flow is first observed at the most upstream location for this nozzle. The high levels of TKE are also confined to a smaller region in this case. Based on these results, the two parametric chevron nozzle designs demonstrate a potential to produce lower jet noise than what is observed in case of a conventional chevron nozzle. Finally, a study of the turbulent flowfields of all the nozzles shows that the mixing between the fan and freestream shear layers still dominates the mixing in the jet flow. However, the chevrons are able to add streamwise vortices to the flow that enhance mixing between the core and fan shear layers to some extent. This promotes better mixing and as a result, the turbulence in the jet plume is reduced.
en
openAccess
Copyright held by the author.
Aerospace engineering
IMPACT OF NEW CHEVRON CONFIGURATIONS ON MIXING ENHANCEMENT IN SUBSONIC JETS
Thesis
oai:kuscholarworks.ku.edu:1808/97792020-07-14T12:52:13Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Loya, Sudarshan K.
2012-06-03T15:24:54Z
2012-06-03T15:24:54Z
2011-12-31
http://dissertations.umi.com/ku:11801
http://hdl.handle.net/1808/9779
Classical one-dimensional (1D) models of automotive catalysts are effective in designing catalyst systems that meet current emission standards. These models use various assumptions in order to simplify the mathematical formulation. Although these postulations have been effective in the past, they might not work with new versions of catalytic converters and the architectures being proposed. In particular, classical models neglect viscosity, conductivity and diffusion in the bulk gas phase. However, in low flow rate regenerative catalysts, these terms might become important. In order to account for these phenomena, an updated model is proposed for the dynamically incompressible flow in the converter. At the same time, derivation and utilization of these terms is studied for proper inclusion in the model. Furthermore, it is evident from the history of catalyst modeling that precise reaction rate expressions are needed for accurate predictions. In order to determine the correct reaction rate expression, this work includes the history of the fundamental reactions of automotive catalysts including carbon monoxide (CO), hydrogen (H2) and nitric oxide (NO) oxidation on a widely used material formulation (platinum catalyst on alumina washcoat). A detailed report of these reactions is incorporated for the reader in order to understand the reaction mechanism along with the creation of a reaction rate expression. Using this review, the CO oxidation reaction is modeled in order to validate the changes proposed in the updated flow model. Moreover, the importance of using the model for determining the characteristics of the catalyst in low flow conditions is presented. This work ends by describing the success and failures of the revised model as compared to the classical model.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Mechanical engineering
Catalytic converter modeling
Diffusion and conduction
Incompressible navier stokes
Low velocity modeling
Reaction rate expression
Dynamic Incompressible Navier-Stokes Model of Catalytic Converter in 1-D Including Fundamental Oxidation Reaction Rate Expressions
Thesis
oai:kuscholarworks.ku.edu:1808/77542018-01-31T20:08:09Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Strunk, Gavin
2011-07-04T20:19:03Z
2011-07-04T20:19:03Z
2010-12-10
http://dissertations.umi.com/ku:11263
http://hdl.handle.net/1808/7754
Biped robots present many advantages for exploration over mobile robots. They do not require a continuous path, which allows them to navigate over a much larger range of terrain. Currently, bipeds have been successful at walking on flat surfaces and non-periodic rough terrain such as stairs, but few have shown success on unknown periodic terrain. The Jaywalker is a 2D walker designed to study locomotion on uneven terrain. It is a fully active robot providing actuation at every joint. A distributed, parallelized, embedded control system was developed to provide the control structure for the Jaywalker. This system was chosen for its ability to execute simultaneous tasks efficiently. The two level control system provides a first level to implement a higher level control strategy, and a second lower level to drive the Jaywalker's systems. The concept was implemented using the Parallax Propeller chip for its relative fast clock frequencies and parallel computing functionality. The chips communicate over a new variation of the I2C bus, which allows multiple slaves to listen to information simultaneously reducing the number of transmissions for redundant data transfers. The system has shown success in taking steps with open loop control. The success of the step is highly dependent on the initial step length using open loop control, but this dependency can be eliminated using closed loop control. The robust structure will provide an excellent platform for uneven terrain locomotion research.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Robotics
Biped
Control
Distributed
Embedded
Parallel
Walking
Parallelized Distributed Embedded Control System for 2D Walking Robot for Studying Rough Terrain Locomotion
Thesis
oai:kuscholarworks.ku.edu:1808/149532018-03-26T21:42:09Zcom_1808_231com_1808_1260col_1808_18153col_1808_7158
Brown, George MacMillan
2014-08-26T19:45:52Z
2014-08-26T19:45:52Z
1915-01-01
Brown, George MacMillan. (1915). "Coal Mining on Pitching Seams." University of Kansas.
http://hdl.handle.net/1808/14953
openAccess
This work is in the public domain according to U.S. copyright law and is available for users to copy, use, and redistribute in part or in whole. No known restrictions apply to the work.
Coal Mining on Pitching Seams
Thesis
oai:kuscholarworks.ku.edu:1808/183462020-06-24T19:27:14Zcom_1808_231com_1808_1260col_1808_18153col_1808_7158
Smith, Howard V.
2015-08-19T21:02:56Z
2015-08-19T21:02:56Z
1921
http://hdl.handle.net/1808/18346
openAccess
This work is in the public domain according to U.S. copyright law and is available for users to copy, use, and redistribute in part or in whole. No known restrictions apply to the work.
The comparative reactivity of some esters of benzoic acid with aniline
Thesis
oai:kuscholarworks.ku.edu:1808/219822018-01-31T20:07:47Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Jiang, Yan
2016-11-15T22:43:10Z
2016-11-15T22:43:10Z
2016-05-31
http://dissertations.umi.com/ku:14586
http://hdl.handle.net/1808/21982
Geosynthetic-Reinforced Retaining (GRR) walls have been extensively used in highway projects. A novel GRR wall was proposed to mitigate the problems (e.g. high connection stress) resulting from the relatively large spacing of primary reinforcement. This new GRR wall has secondary reinforcement installed between primary reinforcement layers. This new GRR wall has a similarity in the structure of the GMSE wall and the GRS wall in terms of the vertical reinforcement spacing (i.e., it has the same vertical primary reinforcement spacing as the GMSE wall and the same vertical secondary reinforcement spacing as the GRS wall). In this study, it is named as a hybrid GRR wall. Since the hybrid GRR wall is an innovative retaining structure, few studies have been carried out on it and then its performance has not been well understood. Therefore, it is necessary to evaluate the performance of the hybrid GRR wall. Three GRR wall sections were constructed and monitored in the field: (1) a hybrid GRR wall section with uniaxial geogrid layers as primary and secondary reinforcement, (2) a hybrid GRR wall section with uniaxial geogrid layers as primary reinforcement and with biaxial geogrid layers as secondary reinforcement, and (3) a GRR wall section with uniaxial geogrid layers as primary reinforcement only (i.e., the control section). Earth pressure cells, inclinometer casings and probes, and foil-type strain gauges were used in these three test wall sections to measure vertical and lateral earth pressures, accumulated lateral wall facing deflections, and strains of primary and secondary geogrid layers during construction, respectively. The results from monitoring of these three GRR wall sections were analyzed. The test results demonstrated the effects of secondary reinforcement on the improved performance of GRR walls, including reduced accumulated wall facing deflections, a more uniform lateral earth pressure distribution, and reduced tensile strains in primary geogrid layers. In addition to the field tests, the numerical study was performed to evaluate the performance of the instrumented GRR walls in the field tests. The wall facing and the foundation soil were modelled as a linearly elastic material and the retained soil was modelled as a linearly elastic perfectly plastic material with the Mohr Coulomb (MC) failure criterion. The behavior of the backfill soil in the reinforced soil zone was modelled using the Cap Yield (CY) model and the MC model. The behavior of the reinforcement was described by a strip element with a linearly elastic perfectly plastic behavior. An 8-kPa compaction stress was considered in the numerical model. The vertical and lateral earth pressures, wall facing deflections, and strains in primary and secondary geogrid layers during construction were calculated by the numerical simulation and also compared with the measured ones in the field tests. The calculated results from the numerical simulation agreed well with the measured one in the field tests. The calculated results from the numerical simulation also demonstrated that the secondary reinforcement could reduce wall facing deflections and tensile strains in primary geogrid layers. A parametric study was also performed through varying one parameter in the baseline model to study its influence on the performance of the hybrid GRR wall, such as wall facing deflections, vertical earth pressures, lateral earth pressures, and stresses in reinforcement. The influence factors consisted of the length of primary reinforcement, the length of secondary reinforcement, the stiffness of primary reinforcement, the stiffness of secondary reinforcement, the backfill soil friction, the backfill soil dilation, the backfill soil modulus, the compaction stress, and the foundation compressibility. The parametric study shows that the maximum wall facing deflection decreased with an increase in the primary reinforcement length, the secondary reinforcement length, the primary reinforcement stiffness, the secondary reinforcement stiffness, the backfill soil friction angle, the backfill soil dilation angle, the backfill soil modulus, and the foundation compressibility while increased with an increase in the compaction stress. The lateral earth pressure increased with an increase in the primary reinforcement stiffness, the secondary reinforcement stiffness, and the backfill soil friction angle because the wall facing deflections decreased with an increase in the primary reinforcement stiffness, the secondary reinforcement stiffness, and the backfill soil friction angle. The maximum tensile stress in the primary reinforcement increased with an increase in the primary reinforcement stiffness and the compaction stress but decreased with an increase in the primary reinforcement length, the secondary reinforcement stiffness, and the backfill soil friction angle.
en
openAccess
Copyright held by the author.
Civil engineering
Geotechnology
Field test
Geosynthetic reinforced retaining wall
Geosynthetic reinforced soil (GRS) wall
Mechanically stabilized earth (MSE) wall
Numerical modelling
Secondary reinforcement
Evaluating Performance of Hybrid Geosynthetic-Reinforced Retaining Walls
Dissertation
oai:kuscholarworks.ku.edu:1808/67292020-08-05T13:48:37Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Yin, Juan
2010-10-03T03:18:47Z
2010-10-03T03:18:47Z
2010-08-26
http://dissertations.umi.com/ku:11134
http://hdl.handle.net/1808/6729
The objective of the proposed research is to study the traffic operational characteristics at four-way-stop-controlled (FWSC) intersections with single -lane approaches. Observational data were collected at six FWSC intersections in Lawrence, Kansas. Then, the necessary traffic data were extracted from the videotapes using data processing programs. With the collected data, a driver behavior based simulation approach was presented to estimate the 95th percentile queue length, control delay and service time. After calibration and validation, the simulation model was used to study characteristics of the queue length, control delay, and service time at FWSC intersections. Finally, intersection capacities were estimated under different traffic conditions.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Civil engineering
Capacity
Fwsc intersections
Simulation
Behavior-Based Simulation Approach for the Capacity and Traffic Operational Characteristic Study of Four-Way-Stop-Controlled Intersections
Dissertation
oai:kuscholarworks.ku.edu:1808/190922017-12-08T21:34:35Zcom_1808_231com_1808_1260col_1808_18153col_1808_7158
Garver, John Diller
2015-12-04T15:09:30Z
2015-12-04T15:09:30Z
1919
http://hdl.handle.net/1808/19092
openAccess
This work is in the public domain according to U.S. copyright law and is available for users to copy, use, and redistribute in part or in whole. No known restrictions apply to the work.
Power requirements in the cement industry
Thesis
oai:kuscholarworks.ku.edu:1808/275362019-01-08T09:01:24Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Kim, Kwang S.
2018-12-21T17:32:30Z
2018-12-21T17:32:30Z
1986
http://hdl.handle.net/1808/27536
The effect of thermal radiation on the solidification of an absorbing, emitting, isotropically scattering infinite and finite, semi-transparent gray medium bounded between two concentric cylinders is investigated. The conservation of energy principle employing enthalpy and temperature as dependent variables is coupled with a set of moment equations which are derived from the radiative transfer equations and Marshak type boundary conditions by applying P-1 differential approximations.
The transient temperature distribution, interface location of a semi-transparent phase change medium, and the local radiative radial and axial heat flux has been obtained by using a Gauss-Seidel iterative numerical scheme for some typical geometric dimensions and parameters. The numerical results for the one-dimensional axisymmetric case of pure conduction are verified by comparison with an analytical approximation where the change in the internal energy in the solid phase is neglected.
The results for an optically thick cylindrical medium are obtained, analyzed, and displayed in graphs.
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Transient conduction and radiation in a semi-transparent phase change medium in an annulus
Dissertation
oai:kuscholarworks.ku.edu:1808/278192021-03-05T18:33:52Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Barforoush, Joseph
2019-05-10T15:13:23Z
2019-05-10T15:13:23Z
2018-12-31
http://dissertations.umi.com/ku:16202
http://hdl.handle.net/1808/27819
Water electrolysis via renewable electricity (e.g., wind, solar) provides a carbon neutral route for pure hydrogen production to fuel zero emission power generation devices, such as fuel cells. Deployment of fuel cell vehicles is growing in the US and around the world, coupled with the construction of hydrogen fueling stations, of which there are expected to be 200 hydrogen refueling stations operating in California by 2025. However, 96% of hydrogen is still produced by steam reformation of natural gas or sourced from other petroleum feedstocks. As a result, the fuel cell vehicles produce zero emissions at the tailpipe but the production of the hydrogen fuel still contributes to greenhouse gas emissions. Moreover, mature technologies essential to the sustenance of the human population, specifically the Haber-Bosch process for the production of ca. 187 million tonnes of ammonia fertilizer per year, account for the majority of hydrogen consumption. Thus, a carbon neutral route for hydrogen production from renewable feedstocks is an exigency for Earth’s inhabitants to avoid the worsening of the catastrophic effects of anthropogenic climate change. Water splitting is a technology that is hundreds of years old, yet it has still not become commercially relevant due to high capital costs and high operating costs of the electrolyzers available today. A major driver of these costs are the hydrogen evolution and oxygen evolution electrocatalysts, which are typically composed of platinum and iridium for operation in acidic electrolyte. The main objective of this doctoral work is to decrease the overpotential of the water splitting reactions by tuning the morphology of earth abundant metal catalysts. Platinum is known to catalyze the hydrogen evolution reaction (HER) at the thermodynamic equilibrium potential, and it is most active in acidic media. However, the corrosive nature of acidic electrolyte causes degradation of non-precious metal catalysts as well as other components that the electrolyte comes into contact with. Various transition metal dichalcogenides have been investigated as alternatives to platinum, but here we report the first nanostructured FeS2 HER catalyst. By utilizing a hot sulfur injection synthesis and adjusting the sulfur concentration, we were able to create one-dimensional (1D) FeS2 wires and two-dimensional (2D) FeS2 discs, unique from the previously known three-dimensional (3D) FeS2 cubes. We found that the catalytic activity of the nanostructured FeS2 was highly dependent on the morphology, and the 2D FeS2 discs had an exchange current density of the same order of magnitude as Pt in neutral electrolyte. The 2D morphology of the FeS2 discs bears resemblance to the 2D MoS2 catalyst which is known to have HER activity in acidic media, with the edges of the 2D nanosheet structure being the active sites. The oxygen evolution reaction (OER) is the largest source of inefficiency in overall water splitting reaction because it is a four electron/four proton transfer reaction. NiFe oxides have emerged as highly active OER catalysts in alkaline media, surpassing the activity of even the precious metal- based catalysts, IrOx and RuOx. Specifically, Ni0.8:Fe0.2 has been shown to be the most active ratio for NiFe catalysts because above ca. 25% iron, segregation of the metals occurs. Utilizing surface interrogation mode of scanning electrochemical microscopy (SI-SECM), we measured the kinetic rate constant(s) of the active sites on crystalline Ni0.8:Fe0.2 and amorphous Ni0.8:Fe0.2. We found that the crystalline Ni0.8:Fe0.2, synthesized at high temperatures, had both ”fast” and ”slow” sites with a rate constant of 1.3 s-1 and 0.05 s-1, respectively, while the amorphous Ni0.8:Fe0.2, synthesized by a low temperature (microwave-assisted) method, only had ”fast” sites with a rate constant of 1.9 s-1. High resolution transmission electron microscopy (HRTEM) and electron diffraction showed that the microwave-assisted Ni0.8:Fe0.2 was amorphous down to the five nanometer scale, indicating that low temperature synthesis is crucial for homogeneous dispersion of the metals and maximization of bimetallic active sites. Further SI-SECM studies revealed that the Ni0.8Fe0.2OOH layered double hydroxide (LDH), a structure known to have electrolyte permeability, had an anomalously high active site density (4500 sites nm-2) compared to that of the crystalline Ni0.8:Fe0.2 (500 sites nm-2), from which it was synthesized by electrochemical conditioning. This gives evidence that electrolyte permeability allows for catalysis via subsurface sites. The final objective of this work was to lower the overall water splitting overpotential with earth abundant metal catalysts. Current water electrolyzers utilize acidic (PEM) or alkaline configurations. However, neither of these configurations are amenable to using the FeS2 discs and nanoamorphous Ni0.8:Fe0.2 oxide for overall water splitting because the former is the most active in neutral media and the latter is most active in alkaline media. By analogy with the chlor-alkali membrane process, we utilized the K+ form of the Nafion 117 membrane to enable water splitting with the anode in alkaline media and the cathode in neutral media, or dual-pH water splitting. With this system, we were able to achieve water splitting at 10 mA cm-2 under 1.6 V—a total overpotential of less than 270 mV—for a 24 h period.
en
openAccess
Copyright held by the author.
Engineering
Earth Abundant
Electrocatalyst
Hydrogen Evolution
Oxygen Evolution
Water Electrolysis
Water Splitting
Earth Abundant Catalysts for Water Electrolysis at Low Overpotentials
Dissertation
oai:kuscholarworks.ku.edu:1808/144922017-12-08T21:45:28Zcom_1808_231com_1808_1260col_1808_18153col_1808_7158
Hansen, George T.
2014-07-03T20:25:53Z
2014-07-03T20:25:53Z
1911-01-01
Hansen, George T. "The Conducting of a Mining
Negotiation Showing the Scheme of Engineering Involved" University of Kansas. 1911.
http://hdl.handle.net/1808/14492
openAccess
This work is in the public domain according to U.S. copyright law and is available for users to copy, use, and redistribute in part or in whole. No known restrictions apply to the work.
The Conducting of a Mining Negotiation Showing the Scheme of Engineering Involved
Thesis
oai:kuscholarworks.ku.edu:1808/297152021-10-28T19:40:49Zcom_1808_1260com_1808_231col_1808_1952col_1808_18153
Zhang, Junjian
2019-11-01T01:31:12Z
2019-11-01T01:31:12Z
2019-05-31
http://dissertations.umi.com/ku:16342
http://hdl.handle.net/1808/29715
https://orcid.org/0000-0001-6155-4291
This dissertation investigates sound propagation in frequency-dependent materials. The study provides an improved understanding of how to numerically model the porous impedance materials more accurately under the conditions of complicated geometries. The finite difference time-domain (FDTD) method is implemented on the linearized Euler equation (LEE), along with the immersed boundary (IB) method and other numerical techniques to simulate the acoustic wave propagation in air, water, porous media and biological tissues. When material properties vary in the frequency domain, their time-domain counterpart may contain either convolution operation or fractional derivative operation. Both operations have been studied in this dissertation. Recursive algorithm methods, piece-wise constant recursive methods (PCRC) and piece-wise linear recursive methods (PLRC) are used to numerically solve for convolution operations, and fractional central difference (FCD) methods are used to solve for fractional Laplacians. Both methods show good results in comparison with analytical solutions. A variety of models have been implemented to simulate the acoustic wave propagation inside porous media. The techniques include: the Zwicker and Kosten (ZK) phenomenological model, the Delany and Bazley model, various porosity two-parameter models, the time-domain boundary condition (TDBC) models, and Wilson’s relaxation model (WRX). A new method is also proposed that utilizes the ANSI/ASA-S1.18 measurements to construct a new relaxation function. The new relaxation function can improve the prediction from the TDBC and WRX models significantly. The ZK and WRX models have also been used in predicting the noise reduction of a house. The noise due to transmission and vibration of the wall is modeled as a simple wave transmission through a porous material layer. A curve fitting method is used to match acoustic properties of the wall material. By assembling all the materials together, the over-all acoustic response of a house can be simulated. When acoustic wave propagating in biological tissues, wave propagation equations were previously solved either with convolutions, which consume a large amount of memory, or with pseudo-spectral methods, which cannot handle complicated geometries effectively. The approach described in this study employs FCD method, combined with the IB method for the FDTD simulation. It also works naturally with the IB method which enables a simple Cartesian-type grid mesh to be used to solve problems with complicated geometries. This work also studies acoustic scattering effects caused by 2D or 3D vortices. The LEE is used to investigate sound wave propagation over subsonic vortices. Instead of traditional direct numerical simulation (DNS) methods, the new approach treats vortex flow field as a scattering background flow and solves the acoustic field with the LEE solver. The numerical method uses a high-order WENO scheme to accommodate the highly convective background flow at high Mach numbers. The study focuses on the acoustic field scaling laws scattered by the 2D and 3D vortices.
en
openAccess
Copyright held by the author.
Aerospace engineering
Acoustics
Computational physics
Aeroacoustics
CFD
Frequence dependent material
Immersed bounday method
porous medium
Time domian simulation
Time-Domain Simulation of Sound Propagation in Frequency-Dependent Materials
Dissertation
oai:kuscholarworks.ku.edu:1808/39452018-01-31T20:08:15Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Bailey, Mark Michael
2008-07-14T19:45:32Z
2008-07-14T19:45:32Z
2008-04-29
http://dissertations.umi.com/ku:2440
http://hdl.handle.net/1808/3945
Diabetes is a disease characterized by defects in insulin utilization, either through autoimmune destruction of insulin-producing cells (Type I) or insulin resistance (Type II). Treatment includes regular insulin injections, which can be painful and inconvenient, often leading to low patient compliance. To overcome this problem, novel formulations of insulin are being investigated, such as inhaled aerosols. Sufficient deposition of powder in the distal regions of the lung to maximize systemic absorption requires precise control over particle size, with particles between 1 and 5 microns in aerodynamic diameter being within the respirable range. Insulin nanoparticles were produced by titrating insulin dissolved at low pH to the pI of the native protein, and were then processed into microparticles using solvent displacement. Particle size, crystallinity, dissolution properties, stability, and powder density were characterized. This work demonstrates that pure insulin microparticles can be produced from nanosuspensions with minimal processing steps and with suitable properties for deposition in the peripheral lung.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Chemical engineering
Pharmaceutical chemistry
Biomedical engineering
Insulin
Pulmonary delivery
Nanotechnology
Drug delivery
Pure Insulin Nanoparticle Agglomerates for Pulmonary Delivery
Thesis
oai:kuscholarworks.ku.edu:1808/43632020-07-22T14:32:45Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Zhang, Fan
2009-02-02T06:42:19Z
2009-02-02T06:42:19Z
2008-01-01
http://dissertations.umi.com/ku:10113
http://hdl.handle.net/1808/4363
Recycling of building materials is an important aspect of sustainable construction, while sustainable construction is a critical issue to fulfill overall sustainable development. Researchers have proved that building materials recycling is technically feasible and facilities for recycling are available, too. They have identified many obstacles of building materials recycling, but most of them are derived from experience. Researchers suggested many ways to maximize building materials recycling, but they are not powerful enough. This thesis will summarize the obstacles and put them into categories. After that, a case study will be used to testify that these are real obstacles. This thesis will focus on developing the concept of building design recyclability by giving the definition of design recyclability, describing the principles that make a design recyclable, generating drives of design recyclability, and testifying these drives. At the end, some suggestions will be given for future research directions.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Civil engineering
Design recyclability
Recycling
Sustainable construction
Framework for Building Design Recyclability
Thesis
oai:kuscholarworks.ku.edu:1808/54502020-07-24T14:25:58Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Biggs, Casey
2009-08-31T02:28:24Z
2009-08-31T02:28:24Z
2009-07-01
http://dissertations.umi.com/ku:10460
http://hdl.handle.net/1808/5450
This thesis expands on the previous work done in the area of intra-pulse radar embedded communication by examining some of the practical aspects of the waveform design. Communication waveform mismatches between the tag and receiver due to multipath distortion, sampling rate differences and using different lengths for the radar waveform are explored for each of the three previously developed design methods. The Dominant-Projection approach is shown to be robust to most mismatches while the other two approaches significantly degrade or fail with any mismatch. Lack of synchronization between the receiver and tag is shown to increase the occurrence of symbol errors, since the receiver is required to search over multiple samples for the communication waveform sent by the tag. Attempts to reduce the number of errors caused by the lack of synchronization are also made, first by taking a three sample average of the filter output and second by generating waveforms with lower local cross-correlation, with both attempts shown to be unsuccessful. Other attempts are also made to improve the waveform design. It is shown that temporal expansion can be used to either improve symbol error rate or reduce the amount of bandwidth expansion required. A rule-of-thumb is developed for the bandwidth expansion versus temporal expansion trade-off. It is also shown that more of the dominant space can be projected out with Dominant-Projection to reduce the probability of symbol error, but this comes at the cost of being more susceptible to being detected by an intercept receiver.
EN
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Electronics and electrical engineering
Communication
Radar
Spread spectrum
Waveform diversity
Practical Considerations for Radar Embedded Communication
Thesis
oai:kuscholarworks.ku.edu:1808/159292018-01-31T20:08:05Zcom_1808_231com_1808_1260col_1808_18153col_1808_1951
Faraj, Rasha Attwan
2014-11-30T18:23:33Z
2014-11-30T18:23:33Z
2014-08-31
http://dissertations.umi.com/ku:13487
http://hdl.handle.net/1808/15929
In the last two decades, a new biofilm process, aerobic granular sludge technology, has been applied by researchers for organic and nutrient removal from municipal wastewater. Most studies have been performed with high strength wastewater and reported granules with irregular shape and incomplete organic and nutrients removal. Slowly biodegradable organic compounds, including the particulate and colloidal fraction, constitute an essential fraction of municipal wastewater. The objective of this study was to investigate the influence of slowly biodegradable organic matters, including particulate compounds, on the morphology, integrity and performance of aerobic granular sludge. Three identical lab-scale aerobic granular reactors (AGRs) were operated for two experimental phases in a sequencing batch reactor (SBR) regime. The objective of the first experimental phase was to develop stable, compact and regular aerobic granules that achieve biological nutrient removal (BNR) of both nitrogen and phosphorus. For both experimental phases, the hydraulic loading rate was 1.32 kg COD/m3/day. For the 1st phase, the three reactors were fed soluble organic matter (sodium acetate) as the sole carbon source with an anaerobic-aerobic SBR cycle. To achieve complete BNR, a post anoxic cycle was included in the SBR cycle. During the second experimental phase, the influence of particulate COD was studied with particulate potato starch being added with and without pretreatment. In the first reactor, particulate starch was included in a 1:1 soluble COD: particulate COD ratio. For the other AGRs, the potato starch was pretreated either with heat hydrolysis or biological fermentation, an anaerobic process. Both pretreatments were applied to increase the bioavailable specific substrate for diffusion into the granular structure and degradation. For both experimental phases, results are presented for granule morphology, integrity and reactor treatment performance. The findings of this study demonstrated that implementing a post anoxic phase remarkably increased both the nitrogen and phosphorous removal performance of the aerobic granules. 96% COD, 94% N and 86% P removal was accomplished after applying the post anoxic period in the SBR cycle. Comparable to previous studies, the free nitrous acid (FNA) inhibited the selection of PAOs when nitrite accumulated in the AGRs. The microscopic investigations and the EPS extraction showed that the presence of particulate starch in the feeding solution influenced the morphology and the structure of the granules. The granule surface had more filamentous growth and a more porous structure. AGR fed with a 1:1 particulate:soluble COD feed also demonstrated reduced nitrogen and phosphorous removal (78 and 81%, respectively). Moreover, only 75% COD removal was accomplished. Microscopy suggests that particulate removal was achieved by surface adsorption, followed by hydrolysis and degradation by microorganisms. Both pretreatments were capable of solubilizing most of the particulate starch. The heat hydrolysis broke down the starch polymers to produce mostly soluble starch, slowly biodegradable compound. This pretreatment also lead to filamentous growth, indicating that both the size and nature of the organic matter affected the aerobic granular sludge. On the other hand, most of the fermentation pretreatment products were VFAs. The anaerobic fermentation pretreatment enhanced and maintained morphology, integrity and performance of the aerobic granular sludge. Therefore, aerobic granular sludge can be successfully applied for BNR from municipal wastewater. However, if high particulate COD fractions are present, a fermentation pretreatment may be necessary.
en
openAccess
This item is protected by copyright and unless otherwise specified the copyright of this thesis/dissertation is held by the author.
Civil engineering
Environmental engineering
aerobic granular sludge
organic and nutrients removal
SBR
slowly biodegradable carbon
wastewater treatment
The Effect of Slowly Biodegradable Carbon on the Morphology, Integrity and Performance of Aerobic Granular Sludge
Thesis
mods///col_1808_18153/100