Engineering Commons^™

The Effect Of Bi-Polar Plate And Membrane Materials On Water Transport In Pemfcs, Visarn Lilavivat

Theses and Dissertations

An analysis of liquid water transport and removal in Proton Exchange Membrane Fuel Cells (PEMFCs) as affected by different membranes and the geometry and surface roughness of bipolar plates on is presented. Four topics are considered. First, the channel dimension and shape of various flow fields have been shown to affect the cell performance and the uniformity in the distributions of current. Typical variations in the channel width, height, and undercut that may occur with manufactured metal plates are studied. These sample-to-sample variations and distributions are studied and compared with laboratory-scale graphite plates. The goal of the work is to …

Ultrawideband (Uwb) And Reconfigurable Antennas - New Concepts For Conformal Load Bearing Antenna Structures (Clas), Nicholas Bishop

Theses and Dissertations

Conformal antennas have been increasingly playing an important role in a vast number wireless of communication applications. More specifically, Conformal Load Bearing Antenna Structures (CLAS) have drawn a great deal of interest among researchers and engineers because of their advantages of multiple functionality, e.g. antenna and structure both. The objectives of this thesis are to investigate and design innovative conformal Ultrawideband (UWB) endfire antenna arrays and reconfigurable aperture coupled pixel patch antennas both of which are good candidates for CLAS. First, a broadband VHF-UHF end-fire Yagi-Uda array is proposed for possible air vehicle integration and operation within the 240-465 MHz …

Dislocation Reduction In Silicon Doped High Aluminum Content Algan Layers For Deep Uv Optoelectronic Devices, Hung-Chi Chen

Theses and Dissertations

III-Nitride based deep ultraviolet (UV) light emitting diodes (LEDs) are prospective candidates to replace the conventional bulky, expensive and environmentally harmful mercury lamp as new UV light sources, used in the applications of water and air purification, germicidal and biomedical instrumentation systems, etc. Due to the lack of native substrates and poor carrier injection, AlGaN-based deep UV LED is suffering from low optical power and low overall efficiency, which prevents the availability of low cost, high efficiency deep UV LED on the market.

This dissertation is focused on improving the efficiency of deep UV LEDs, by improving the base template …

Effects Of N-Type Doping On Algan Material Quality, Devendra Diwan

Theses and Dissertations

The field of group III-nitride semiconductors has seen incredible developments during last couple of decades. They are recognized as the most promising materials for a wide field of optoelectronics and electronic devices. Their bandgap ranges from 6.2 eV for AlN to 0.7 eV for InN, covering a wide spectral range from infrared (1.77 mm) to deep ultraviolet (200 nm). Their direct bandgap makes them useful for fabricating optoelectronic devices such as light emitting diodes (LEDs), laser diodes (LDs), and photodetectors. III-nitride semiconductor materials also possess strong bond strengths and exhibit good structural, chemical and thermal stability. These properties make it …

Fault Protection In Dc Distribution Systems Via Coordinated Control Of Power Supply Converters And Bus Tie Switches, Pietro Cairoli

Theses and Dissertations

A new fault protection method responds to the current needs of emerging dc power distribution systems by coordinating electronic power converters and mechanical contactors to rapidly isolate short circuit faults while maintaining continuity of power to loads. This work is important because the increasing performance, higher efficiency, and decreasing cost of electronic power converters have spurred a rediscovery and proliferation of dc power distribution systems. Although dc distribution offers advantages such as higher transmission efficiency, higher power density, higher reliability, and ease of interfacing asynchronous sources, enthusiasm for adopting dc technologies suffers from widespread concern over the means to protect …

Acoustic Emission Source Characterization Of Fatigue Crack Extension In Steel Bridge Material, Md Mozahid Hossain

Theses and Dissertations

The probability of Acoustic Emission (AE) detection associated with fatigue crack extension in steel bridge components is a difficult problem due to the complexity of the AE sources. AE is a very promising technique for structural health monitoring and automated micro-crack detection as it is generated by the material itself, unlike other nondestructive testing techniques (for example impact echo and ultrasonics), which require external input sources. Characterizing the source of AE is an ongoing challenge because AE sensors are not only sensitive to the AE signals but also to mechanical noise and reflections. It is therefore difficult to interpret the …

Liquefaction Potential Of South Carolina Coastal Plain Soils Using Dilatometer Data, Joseph Ronald Williamson

Theses and Dissertations

In recent years much research has been focused on developing the flat plate dilatometer (DMT) as a tool to estimate the liquefaction potential of soils. Currently the DMT is over shadowed by the more accepted methods of estimating liquefaction potential which utilize test data from either the standard penetration test (SPT), cone penetration test (CPT), or shear wave velocity test (Vs). The SPT, CPT, and V_s tests are all well-developed methods of estimating liquefaction potential and are supported by extensive databases; however, the DMT is believed by many researchers to be the superior alternative. Due to the DMT's minimal …

An Analysis Of Constructive Network Formation Models, Gary Fredericks

Theses and Dissertations

We study a family of network formation models to determine how payment rules affect the final network topologies that emerge. In our model a set of nodes starts out without any edges and the nodes must pay for the creation of edges using one of several different payment mechanisms. Example payment mechanisms include one node paying for the whole edge, and the cost being shared equally between the two nodes. We show how the set of networks formed by some payment rules are subsets of those formed by other rules. We also perform extensive empirical tests on networks of up …

Plc Code Vulnerabilities Through Scada Systems, Sidney E. Valentine, Jr.

Theses and Dissertations

Supervisory Control and Data Acquisition (SCADA) systems are widely used in automated manufacturing and in all areas of our nation's infrastructure. Applications range from chemical processes and water treatment facilities to oil and gas production and electric power generation and distribution. Current research on SCADA system security focuses on the primary SCADA components and targets network centric attacks. Security risks via attacks against the peripheral devices such as the Programmable Logic Controllers (PLCs) have not been sufficiently addressed.

Our research results address the need to develop PLC applications that are correct, safe and secure. This research provides an analysis of …

Book Review: Placing The Suspect Behind The Keyboard: Using Digital Forensics And Investigative Techniques To Identify Cybercrime Suspects, Thomas Nash

Journal of Digital Forensics, Security and Law

In this must read for any aspiring novice cybercrime investigator as well as the seasoned professional computer guru alike, Brett Shaver takes the reader into the ever changing and dynamic world of Cybercrime investigation. Shaver, an experienced criminal investigator, lays out the details and intricacies of a computer related crime investigation in a clear and concise manner in his new easy to read publication, Placing the Suspect behind the Keyboard. Using Digital Forensics and Investigative techniques to Identify Cybercrime Suspects. Shaver takes the reader from start to finish through each step of the investigative process in well organized …

Automating Vendor Fraud Detection In Enterprise Systems, Kishore Singh, Peter Best, Joseph Mula

Journal of Digital Forensics, Security and Law

Fraud is a multi-billion dollar industry that continues to grow annually. Many organizations are poorly prepared to prevent and detect fraud. Fraud detection strategies are intended to quickly and efficiently identify fraudulent activities that circumvent preventative measures. In this paper, we adopt a DesignScience methodological framework to develop a model for detection of vendor fraud based on analysis of patterns or signatures identified in enterprise system audit trails. The concept is demonstrated by developing prototype software. Verification of the prototype is achieved by performing a series of experiments. Validation is achieved by independent reviews from auditing practitioners. Key findings of …

Book Review: Professional Penetration Testing: Creating And Learning In A Hacking Lab 2e, Joshua Bartolomie

Journal of Digital Forensics, Security and Law

Organizations often strive for proactive information security programs in an effort to limit occurrence and impact of security breaches. However, traditional security programs run the risk of being unable to provide adequate insight and proactive awareness into real attack vectors that may exist within their organizations. With attack methods and efforts becoming increasingly aggressive, and effective, organizations must take equally assertive measures to protect their critical information and assets. Penetration testing is one of those tools that is often misunderstood, overlooked, and undervalued. A true adversary would not hesitate to exploit every potential to gain entry or cause a disruption …

Technology Corner: Calculating The Number Of Android Lock Patterns: An Unfinished Study In Number Theory, Gary C. Kessler

Journal of Digital Forensics, Security and Law

Although one is unlikely to ever want to brute-force an Android lock pattern, many do wonder about the relative strength of the lock pattern versus a multidigit personal identification number (PIN). It becomes obvious pretty quickly that there are many more lock patterns than the 10,000 possible four-digit PINs.

Science Column: Reconstruction: The Experimental Side Of Digital Forensics, Fred Cohen

Journal of Digital Forensics, Security and Law

Many in digital forensics seem to forget that the science part of digital forensics means experimentation and that implies a whole lot of things that most practitioners never learned.

Book Review: Iphone And Ios Forensic: Investigation, Analysis And Mobile Security For Apple Iphone, Ipad And Ios Devices, Simson Garfinkel

Journal of Digital Forensics, Security and Law

In April 2011 news outlets around the world revealed shocking news about Apple’s iPhone: for reasons that were not apparently clear, every iPhone contained a small SQLite database that logged where and when the user had been whenever the phone was turned on, and those records went back for pretty much as long as the user had owned their phone. Apple eventually declared that the data cache was the result of a bug and issued a software update to prune the database (it had previously grown without limit). Privacy activists rejoiced that their beloved iPhones were once again trustworthy. But …

Table Of Contents

Journal of Digital Forensics, Security and Law

No abstract provided.

Review Of Us And Eu Initiatives Toward Development, Demonstration, And Commercialization Of Lignocellulosic Biofuels, Venkatesh Balan, David Chiaramonti, Sandeep Kumar

Civil & Environmental Engineering Faculty Publications

Advanced biofuels produced from lignocellulosic biomass offer an exciting opportunity to produce renewable liquid transportation fuels, biochemicals, and electricity from locally available agriculture and forest residues. The growing interest in biofuels from lignocellulosic feedstock in the United States (US) and the European Union (EU) can provide a path forward toward replacing petroleum-based fuels with sustainable biofuels which have the potential to lower greenhouse gas (GHG) emissions. The selection of biomass conversion technologies along with feedstock development plays a crucial role in the commercialization of next-generation biofuels. There has been synergy and, even with similar basic process routes, diversity in the …

The Anti-Angiogenic Effects Of Sparstolonin B, Henry Rhodes Bateman

Theses and Dissertations

Sparstolonin B (SsnB) is a novel bioreactive compound isolated from Sparganium stoloniferum, an herb historically used in Traditional Chinese Medicine as an anti-tumor agent. SsnB has demonstrated anti-inflammatory properties, inhibiting Toll-like receptor mediated inflammation in isolated macrophages and in mice. Angiogenesis, the process of new capillary formation from existing blood vessels, is dysregulated in many pathological disorders, including atherosclerosis, diabetic retinopathy, and tumor growth. The goal of the project was to investigate the anti-angiogenic effects of SsnB.

The first part of the project utilized in vitro functional assays to study how SsnB affected endothelial cells. SsnB inhibited endothelial cell tube …

Mass Spectrometry And Tandem Mass Spectrometry Characterization Of Protein Patterns, Protein Markers And Whole Proteomes For Pathogenic Bacteria, Jennifer Intelicato-Young

Theses and Dissertations

There have been many recent reviews published on MALDI-TOF MS (matrix assisted laser desorption/ionization time-of-flight) MS (mass spectrometry) for identification of bacteria particularly with relevance to clinical microbiology. MALDI-TOF MS is now a mature technique for bacterial identification with great promise. The purpose of this review is to put into perspective MALDI-TOF MS and other widely used mass spectrometry methods for characterization of proteins. MALDI-TOF MS is used for rapid determination of a mass pattern of proteins for bacterial characterization; these proteins

are generally not identified. Alternatively, after gel separation, MALDI TOF-TOF MSMS (tandem mass spectrometry) or on-line LC-ESI MS-MS …

High Fat Diet Induced Obesity In A Mouse Model For Colorectal Cancer, Kennerly Clinton Patrick

Theses and Dissertations

Obesity is widely correlated with the incidence of colorectal cancer (CRC). The exact mechanisms that link obesity to CRC risk have not yet been fully established, and only a limited number of animal models are available to study pathways involved in obesity-related colon carcinogenesis. The objective of this study was to determine the influence of HFD-induced obesity on AOM/DSS-mediated colorectal tumorigenesis, tumor proliferation, and symptom severity. Male C57BL/6 mice were fed a novel high fat diet, designed to mimic the standard American diet (12 % saturated fat & 28 % unsaturated fat), at 4 weeks of age until 16 weeks …

Design And Analysis Of An Electronically Steerable Microstrip Patch And A Novel Coplanar Waveguide (Cpw) Fed Slot Antenna Array, Hamad Shaban Aldossary

Theses and Dissertations

Conformal Phased Array Antennas (CPAAs) are very attractive for their high gain, low profile, and beam scanning ability while being conformal to their mounting surface. Among them are microstrip patch phased arrays and wideband slot phased arrays which are of particular significance.

In this work, first the study, design, and implementation of a conformal microstrip patch phased array is presented which consists of a high gain beam scanning array implemented using microstrip delay lines controlled using GaAs SPDT switches. Then the study and design of a wideband Coplanar Waveguide (CPW)-fed slot phased array antenna is presented. In both cases the …

Coordinated Control Of Power Electronic Converters In An Autonomous Microgrid, Gholamreza Dehnavi

Theses and Dissertations

Advances in power electronics and generation technologies have increased the viability of distributed generation systems. A microgrid is a special category of distributed generation systems that is distinguished by its size and the ability to operate independently as an islanded system. As long as a microgrid is connected to a large grid, quality of the voltage is supported by the main grid and each power source connected to the microgrid generates independently. In contrast, in the islanded operation of microgrids and in electrical islands such as shipboard distribution systems, dynamics are strongly dependent on the connected sources and on the …

Passive Equalizer Topology Analysis For Signal Integrity Applications, Kuo-Lun Yen

Theses and Dissertations

In high-speed, high density PCB bus systems, high frequency signal losses and crosstalk can have great impacts on signal integrity and digital timing, which can distort transmitted signals, worsen eye diagrams, and attenuate signal amplitudes. Also, these impacts make digital signals and their energy smearing over multiple bit positions as known as jitters, and cause the phenomenon of inter-symbol interference (ISI) in digital signal transmissions.

The main objective of this thesis is to analyze and develop efficient topology circuits for compensating bus system high frequency losses by using equalization techniques. The thesis has focused on study of various practical and …

Three-Dimensional Evolution Of Mechanical Percolation In Nanocomposites With Random Microstructures, Bethany Suzanne Fralick

Theses and Dissertations

One mechanism that is expected to play a large role in the enhanced, and sometimes novel, mechanical properties of nanocomposites is the probabilistic formation of percolated or connected microstructures. The majority of the models used to describe mechanical percolation have the functional form of a power law and depend on prior knowledge of a percolation threshold or critical volume fraction. While these models have been fairly accurate predictors of electrical conductivity in composites, they do not take any microstructural mechanisms, other than connectivity, into consideration. Classic mean-field micromechanics models, however, do not capture the variability in effective properties due to …

Microstructural-Based Modeling Of Electrical Percolation In Polymer Nanocomposites, Neelima Yellepeddi

Theses and Dissertations

Polymer nanocomposites (PNCs) represent a radical alternative to conventional filled polymers or polymer blends. In contrast to conventional composites, where the included phase is on the order of micrometers, PNCs are defined as those that have discrete constituents on the order of a few hundred nanometers. The value of PNCs is not solely based on tailoring mechanical properties, as in traditional composite design and manufacture, but rather on the potential for the design and optimization of multi-functional properties. There is major interest in these polymeric materials embedded with a conductive nanoscale filler. This is due to the possibility of designing …

Boiling And Evaporation On Micro/Nanoengineered Surfaces, Xianming Dai

Theses and Dissertations

Two-phase transport is widely used in energy conversion and storage, energy efficiency and thermal management. Surface roughness and interfacial wettability are two major impact factors for two-phase transport. Micro/nanostructures play important roles in varying the surface roughness and improving interfacial wettability. In this doctoral study, five types of micro/nanoengineered surfaces were developed to systematically study the impacts of interfacial wettability and flow structures on nucleate boiling and capillary evaporation. These surfaces include: 1) superhydrophilic atomic layer deposition (ALD) coatings; 2) partially hydrophobic and partially hydrophilic composite interfaces; 3) micromembrane-enhanced hybrid wicks; 4) superhydrophilic micromembrane-enhnaced hybrid wicks, and 5) functionalized carbon …

Toward Sophisticated Controls Of Two-Phase Transport At Micro/Nano-Scale, Fanghao Yang

Theses and Dissertations

Through the use of latent heat evaporating, flow boiling in microchannels offers new opportunities to enable high efficient heat and mass transport for a wide range of emerging applications such as high power electric/electronic/optical cooling, compact heat exchangers and reactors. However, flow boiling in microchannels is hampered by several severe constraints such as bubble confinement (e.g., slug flow), viscosity and surface tension force-dominated flows, which result in unpredictable flow pattern transitions and tend to induce severe flow boiling instabilities (i.e. low-frequency and large magnitude flows) and suppress evaporation and convection.

In this dissertation, three novel micro/nanoscale thermo-fluidic control methodologies were …

Multi-Label Segmentation Propagation For Materials Science Images Incorporating Topology And Interactivity, Jarrell Waggoner

Theses and Dissertations

Segmentation propagation is the problem of transferring the segmentation of an image to a neighboring image in a sequence. This problem is of particular importance to materials science, where the accurate segmentation of a series of 2D serial-sectioned images of multiple, contiguous 3D structures has important applications. Such structures may have prior-known shape, appearance, and/or topology among the underlying structures which can be considered to improve segmentation accuracy. For example, some materials images may have structures with a specific shape or appearance in each serial section slice, which only changes minimally from slice to slice; and some materials may exhibit …

Assessing Corrosion Damage In Post -Tensioned Concrete Structures Using Acoustic Emission & A Preliminary Investigation Of Biopolymer Doped Cement Mortar For Use In Structural Restoration, Aditya Appalla

Theses and Dissertations

A sizeable portion of the civil infrastructure is made from concrete. An estimate shows that about 7 billion cubic meters of concrete is made annually worldwide. With the deterioration of the infrastructure due to aging or external factors, significant monetary and technological investment is needed for condition evaluation, maintenance and repair. Two areas that account for a considerable portion of this investment are condition evaluation for maintenance of corroded concrete structures and mortar patching for repair and rehabilitation.

The primary method of evaluation of a structure is by visual inspection. But this method is limited as some crucial areas in …

Effect Of Nanoparticle Size, Support, And Potassium Dopant On Ruthenium Activity For Levulinic Acid (La) Hydrogenation To Γ-Valerolactone (Gvl), Shuo Cao

Theses and Dissertations

The purpose of this thesis is to study the effect of nano-particle size, support and potassium dopant on ruthenium activity on the levulinic acid (LA) hydrogenation to ã-valeroactone (GVL).In hydrogenation reaction, H2 as the gas phase reactant reacts with the metal atoms at the surface of particle size, thus a high level of metal dispersion is critical to maximize the amount of atoms on the surface. This reaction has been widely investigated by varied metal supported catalysts and proved that Ru is the most active metal for it. However, most of researchers only focused on the reaction pathway, rather than …