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Optimization Of Bipolar Plate Design For Flow And Temperature Distributions Using Numerical Techniques, Kiran Mohan Veepuri
Optimization Of Bipolar Plate Design For Flow And Temperature Distributions Using Numerical Techniques, Kiran Mohan Veepuri
UNLV Retrospective Theses & Dissertations
Although water is fed controllably into the flow channels in the bipolar plates surrounding the membrane electrode assembly (MEA), the complex flow geometry can lead to non-uniformity of the flow and temperature distribution inside the channels. In addition, non-uniform temperature distribution in the cell will affect the electrochemical process for hydrogen production or fuel cell applications. There are many studies on the theoretical analysis of fuel cells, but not many have been reported on the characteristics of the PEM electrolyzer; In this thesis work, numerical simulations were carried out on the basic bipolar plate given by the Proton Energy Systems …
Design And Control Of A Vibration Isolator Using A Biased Magnetorheological Elastomer, Saul Opie
Design And Control Of A Vibration Isolator Using A Biased Magnetorheological Elastomer, Saul Opie
UNLV Retrospective Theses & Dissertations
The objective of this work is to explore the capability of a Semi-Active (SA) elastomer and control techniques in the area of shock and vibration isolation. Typical passive isolation methods have short comings in meeting competing objectives. A specific problem is isolating electronic packages mounted to military vehicle walls from shock. Often passive elastomer based isolators are used. The ideal solution for shock isolation is a soft lightly damped isolator. However a soft lightly damped isolator will cause excessive sway during normal driving conditions. Further, vehicle dynamics during normal driving conditions are typically in the range of a few hertz, …
Three-Dimensional Numerical Study Of Proton Exchange Membrane Fuel Cell Design, Jianfei Wu
Three-Dimensional Numerical Study Of Proton Exchange Membrane Fuel Cell Design, Jianfei Wu
UNLV Retrospective Theses & Dissertations
Performance of proton exchange membrane (PEM) fuel cells is dependent of a set of complex physical and chemical processes occurring simultaneously. Bipolar plates are important components of PEM fuel cells because they are the first stage of the flow distribution system. A non-uniform flow distribution across the active reaction area within PEM fuel cells will probably lead to an unbalanced use of the precious catalyst, and a lower overall efficiency of the device than expected. A three-dimensional numerical model has been developed to evaluate the PEM fuel cell including the current collectors, flow channels, gas diffusion layers, and membrane. This …
The Treatment Of Selective Mutism: A Case Control Alternating Treatments Design, Jennifer L Vecchio
The Treatment Of Selective Mutism: A Case Control Alternating Treatments Design, Jennifer L Vecchio
UNLV Retrospective Theses & Dissertations
This was the first study to examine the differential effectiveness of two behavioral interventions for selective mutism while employing a single-case alternating treatments design with documentation of treatment outcomes, calculation of effect size, and measures of treatment integrity. Participants were recruited via press release to the local media and the Clark County School District. Interested participants were initially screened over the telephone. If the screening indicated that a child met diagnostic criteria for selective mutism and did not meet exclusionary criteria, an assessment was scheduled. Each participant was assessed by the Anxiety Disorders Interview Schedule for Children for DSM-IV Child …
Design Implementation And Analysis Of A Dynamic Cryptography Algorithm With Applications, Sourabh Ghose
Design Implementation And Analysis Of A Dynamic Cryptography Algorithm With Applications, Sourabh Ghose
UNLV Retrospective Theses & Dissertations
Cryptographers need to provide the world with a new encryption standard. DES, the major encryption algorithm for the past fifteen years, is nearing the end of its useful life. Its 56-bit key size is vulnerable to a brute-force attack on powerful microprocessors and recent advances in linear cryptanalysis and differential cryptanalysis indicate that DES is vulnerable to other attacks as well. A more recent attack called XSL, proposes a new attack against AES and Serpent. The attack depends much more critically on the complexity of the nonlinear components than on the number of rounds. Ciphers with small S-boxes and simple …
The New Middle School: Participatory Design And Outcomes, Tina Wichmann
The New Middle School: Participatory Design And Outcomes, Tina Wichmann
UNLV Retrospective Theses & Dissertations
Effective school design is a multi-faceted endeavor that involves an assessment of academic goals, an evaluation of architectural factors, a survey of current research and trends, and an understanding of past precedent. However, despite these efforts, the specific sociological needs of the occupants that use the school facilities are often overlooked. This thesis explores student and faculty opinions on the predominant trends in educational architecture as they pertain to the "social" spaces of the current CCSD middle school prototype; The primary purpose of this thesis is to explore the attitudes of students and faculty with respect to their current middle …
Design Of Sputtering System For Hemispherical Boron 10 Target, Priya Raman
Design Of Sputtering System For Hemispherical Boron 10 Target, Priya Raman
UNLV Retrospective Theses & Dissertations
10Boron (10B) is an isotope of Boron. 10B and neutron interaction yields alpha particles. alpha particles typically deposit their energy within a few tenths of nanometers within a semiconductor creating electron-hole pairs which through radiative recombination yield photon emission of band gap energy. The number of photons emitted directly relates to the energy and flux density of incoming neutron. Thus, 10B coated semiconductors can be used as a neutron detectors. 10B is an expensive material, especially in the disc and the powdered form which is needed for sputtering. Since a hemispherical target of 10B of diameter 4.8cm was available, a …
Design And Spectral Analysis Of A Six-Axis Shaker System, Yasoda Krishna Prasad Dhulipalla
Design And Spectral Analysis Of A Six-Axis Shaker System, Yasoda Krishna Prasad Dhulipalla
UNLV Retrospective Theses & Dissertations
Shaker table assemblies can exhibit resonances within their frequency range of operation. The spectral analysis of a six-axis shaker system permits the identification and prediction of resonance frequencies. In the project described here, a small six-axis shaker was tested experimentally. In parallel with the experiments, Finite Element (FE) models of the shaker were generated, and their dynamic performance was simulated. Time data from experimental test series were compared with the responses from FE analysis obtained for identical test conditions. The comparison of the response spectra between experiments and simulation permits the assessment and validation of FE analysis as a predictive …
Design And Implementation Of Bibliographic Database, Kiranmayi Karamcheti
Design And Implementation Of Bibliographic Database, Kiranmayi Karamcheti
UNLV Retrospective Theses & Dissertations
In this thesis, we investigate the issues associated with the design and implementation of a comprehensive bibliographic database. Of particular interest is identification and implementation of recursive queries; The design process will be dictated by dependencies and constraints as set by the scientific communities. The final design will be represented in the Unified Modeling Language (UML). The physical database and associated recursive queries are implemented in the Oracle database management system.
Defense Against Buffer Overflow Attack By Software Design Diversity, Kunal Metkar
Defense Against Buffer Overflow Attack By Software Design Diversity, Kunal Metkar
UNLV Retrospective Theses & Dissertations
A buffer overflow occurs during program execution when a fixed-size buffer has had too much data copied into it. This causes the data to overwrite into adjacent memory locations, and, depending on what is stored there, the behavior of the program itself might be affected; Attackers can select the value to place in the location in order to redirect execution to the location of their choice. If it contains machine code, the attacker causes the program to execute any arbitrary set of instructions---essentially taking control of the process. Successfully modifying the function return address allows the attacker to execute instructions …
Applying Of Mechanical Failure Criteria Of Brittle Material To The Design Of High Temperature Heat Exchanger, Taha Mohamed
Applying Of Mechanical Failure Criteria Of Brittle Material To The Design Of High Temperature Heat Exchanger, Taha Mohamed
UNLV Retrospective Theses & Dissertations
Previous studies have suggested using a ceramic high temperature heat exchanger as a sulfuric acid decomposer for hydrogen production within the sulfur iodine thermochemical cycle. The decomposer was manufactured using fused ceramic layers that allow the creation of channels with dimensions below one millimeter. The heat exchanger is expected to operate in the range of 950°C. Thermal stresses are however induced in the heat exchanger ceramic components. In this study, proper failure criteria are selected to evaluate the safety level of the ceramic components. A three-dimensional computational model is developed to investigate the fluid flow, heat transfer, stresses and chemical …
Design And Implementation Of Noc Routers And Their Application To Prdt-Based Noc's, Shankar Narayanan Neelakrishnan
Design And Implementation Of Noc Routers And Their Application To Prdt-Based Noc's, Shankar Narayanan Neelakrishnan
UNLV Retrospective Theses & Dissertations
With a communication-centric design style, Networks-on-Chips (NoCs) emerges as a new paradigm of Systems-on-Chips (SoCs) to overcome the limitations of bus-based communication infrastructure. An important problem in the design of NoCs is the router design, which has great impact on the cost and performance of a NoC system. This thesis is focused on the design and implementation of an optimized parameterized router which can be applied in mesh/torus-based and Perfect Recursive Diagonal Torus (PRDT)-based NoCs; In specific, the router design includes the design and implementation of two routing algorithms (vector routing and circular coded vector routing), the wormhole switching scheme, …
Determining The Competitive Nature Of Physical Therapy Education: A Multi Case Study Design, Peter Andrew Altenburger
Determining The Competitive Nature Of Physical Therapy Education: A Multi Case Study Design, Peter Andrew Altenburger
UNLV Retrospective Theses & Dissertations
Higher education is becoming more competitive as for-profit and non-profit institutions continue to expand. Healthcare educational programs, such as physical therapy, find themselves competing for quality applicants. Understanding this competitive environment and how to thrive within is critical for program survival. The purpose of this study was to determine the competitive strategies being used by entry-level doctorate programs in physical therapy; Eight physical therapy programs, ranked in the top 15% of schools, were purposively selected for the study. Four of the programs were private institutions represented by the University of Southern California (USC), University of Miami, Northwestern University, and Creighton …
Design And Evaluation Of Multi-Axis Vibration Shaker Concepts, Brinda Holur Venkatesh
Design And Evaluation Of Multi-Axis Vibration Shaker Concepts, Brinda Holur Venkatesh
UNLV Retrospective Theses & Dissertations
Elastic bodies exhibit structural resonance and mode shapes at various natural frequencies. In order to avoid structural overloads and equipment malfunctions, elastic systems, mechanical and/or electrical must be evaluated and tested for their performance over the entire frequency range of their operations. Shaker systems replicate the dynamic loads encountered in a field environment, and are used for vibration testing of elastic structures. Such vibration testing ensures the reliable performance of the final product; The objective of this research project, sponsored by the Army Research Lab (ARL), is the design and Finite Element evaluation of a new multi-axis shaker system, which …
Development Of An Integrated Process Simulation System Model For Spent Fuel Treatment Facility (Sftf) Design, Matthew S Hodges
Development Of An Integrated Process Simulation System Model For Spent Fuel Treatment Facility (Sftf) Design, Matthew S Hodges
UNLV Retrospective Theses & Dissertations
Major issues concerning nuclear waste storage at Yucca Mountain are that of safety and long term disposal. Approximately one percent of the content of spent nuclear fuel is that which is responsible for nearly all the long-term associated health risks. The removal and transmutation of this content will render the toxicity of the remaining waste to that of natural uranium within a few hundred years. The research contained in this thesis details several simulations that are involved in the overall removal process. The first objective was to test the feasibility of the design of a distillation column that will separate …
Design And Optimization Of Joints To Mitigate Shock In Military Vehicles Under Blast And Impact Loading, Umakanth Sakaray
Design And Optimization Of Joints To Mitigate Shock In Military Vehicles Under Blast And Impact Loading, Umakanth Sakaray
UNLV Retrospective Theses & Dissertations
Shock from a blast loading may risk the lives of the occupants of a military vehicle and damage the sensitive electronic components within it. The objective of this work is to develop an approach to mitigate shocks due to mine blast loading and impact loading by proper design of joint(s) in the military vehicles. Two types of vehicle configurations are studied for this purpose. The first vehicle is studied to examine ways to mitigate shock due to mine blast while the second vehicle is studied to mitigate shock due to projectile impact load. The proposed research includes design of joints …
Adaptive Design Of Delta Sigma Modulators, Gregory Kenneth Lull
Adaptive Design Of Delta Sigma Modulators, Gregory Kenneth Lull
UNLV Retrospective Theses & Dissertations
In this thesis, a genetic algorithm based on differential evolution (DE) is used to generate delta sigma modulator (DSM) noise transfer functions (NTFs). These NTFs outperform those generated by an iterative approach described by Schreier and implemented in the delsig Matlab toolbox. Several lowpass and bandpass DSMs, as well as DSM's designed specifically for and very low intermediate frequency (VLIF) receivers are designed using the algorithm developed in this thesis and compared to designs made using the delsig toolbox. The NTFs designed using the DE algorithm always have a higher dynamic range and signal to noise ratio than those designed …
Design Of Personalized Location Areas For Future Pcs Networks, Radhika Varadarajan
Design Of Personalized Location Areas For Future Pcs Networks, Radhika Varadarajan
UNLV Retrospective Theses & Dissertations
In Global Systems for Mobile Communications (GSM), always-update location strategy is used to keep track of mobile terminals within the network. However future Personal Communication Networks (PCS) will require to serve a wide range of services (digital voice, video, data, and email) and also will have to support a large population of users. Under such demands, determining the exact location of a user by traditional strategies would be difficult and would result in increasing the signaling load imposed by location-update and paging procedures. The problem is not only in increasing cost, but also in non-efficient utilization of a precious resource, …
Application Of Computational Fluid Dynamics For High Energy Efficiency Design With Human Comfort Of Cad-Vav And Ufad Systems, Bhanu Rekha Bandhakavi
Application Of Computational Fluid Dynamics For High Energy Efficiency Design With Human Comfort Of Cad-Vav And Ufad Systems, Bhanu Rekha Bandhakavi
UNLV Retrospective Theses & Dissertations
This thesis deals with the numerical simulation of the ceiling air distribution (CAD) system and the Under Floor Air Distribution (UFAD) system based on the dimensions of BTLab at UNLV. Ceiling Air Distribution (CAD) with variable air volume (VAV) and Under Floor Air Distribution (UFAD) systems have been widely used in different countries. CAD-VAV and UFAD systems designs have been influenced by increasing emphasis on indoor air quality (IAQ), energy conservation, environmental effects, safety, and economics. So, 3-D Computational Fluid Dynamics (CFD) analysis technique was applied to design high energy efficiency and human comfort CAD-VAV and UFAD systems. The goal …
Las Vegas Community Design Center, Kenneth Thayne Levesque
Las Vegas Community Design Center, Kenneth Thayne Levesque
UNLV Retrospective Theses & Dissertations
The thesis focuses on a certain organization that aids cities and their citizens in the growth of communities, the Community Design Center (CDC). This paper seeks to understand the qualities of a CDC. The first chapter discusses concepts of community and design. A history discussion identifies when CDCs developed in contemporary form and investigates the types of goals CDCs strive to accomplish. The next four chapters consist of three case studies and analysis of selected contemporary CDCs: the Los Angeles Community Design Center; Environmental Works; and Pratt Institute Center for Community and Environmental Development. This paper is intended to provide …
Joint Design For Shock Mitigation, Gopi Nallani
Joint Design For Shock Mitigation, Gopi Nallani
UNLV Retrospective Theses & Dissertations
Smart projectiles carry various electronic components that can be damaged by severe shock loads. Propagation of shock from the region of initial loading to the locations of critical components can result in their failure. The objective of the research is to mitigate (absorb/reflect/disrupt, etc.) the incident shock loading, including simulating set-back, set-forward and balloting loads on a projectile as it exits the gun muzzle and predicting the structural response of internal electronic components. A detailed finite element analysis of the projectile and internal components is presented. The effect of electronic component mounting location on peak acceleration and RMS acceleration has …
Virtual Design And Modeling Of Various Manufacturing Processes For Remote Fabrication Of Transmuter Fuel, Jamil Mohamad Renno
Virtual Design And Modeling Of Various Manufacturing Processes For Remote Fabrication Of Transmuter Fuel, Jamil Mohamad Renno
UNLV Retrospective Theses & Dissertations
As currently envisioned, over 70,000 tons of high-level nuclear waste would be stored inside the planned Yucca Mountain repository. After emplacement, the site must be maintained and guarded for over 10,000 years; The reprocessing of spent nuclear fuel is a possible alternative to geological storage. Here, depleted Uranium would be separated from Plutonium and Minor Actinides. While Plutonium can be 'burned' in commercial nuclear reactors, the minor actinides would be transmuted into other elements. The large-scale deployment of remote fabrication and refabrication processes (approx. 100 tons of Minor Actinides (MA) annually) will be required. Process automation has the potential to …
Application Of Computational Fluid Dynamics On Smart Wing Design, Parthasarathy Chinnasamy
Application Of Computational Fluid Dynamics On Smart Wing Design, Parthasarathy Chinnasamy
UNLV Retrospective Theses & Dissertations
The instantaneous shape of the wing has a profound effect on the fluid dynamic forces it can generate. Visualization of the results obtained from the CFD code gives a better understanding of the happenings around a bending airfoil. The proposed Computational Fluid Dynamics (CFD) model provides detailed design information for the lift and drag forces, velocity and static pressure changes around an airfoil during take off, flying, and lanDing Commercial CFD package---FLUENT is used to evaluate the smart material airfoil aerodynamics performance. The results are then compared with the parametric conventional wings---the wings with flaps. Using smart materials the wings …
Design And Implementation Of A Fast Fourier Transform Architecture Using Twiddle Factor Based Decomposition Algorithm, Bhaarath Kumar
Design And Implementation Of A Fast Fourier Transform Architecture Using Twiddle Factor Based Decomposition Algorithm, Bhaarath Kumar
UNLV Retrospective Theses & Dissertations
With the advent of signal processing and wireless communication mobile platform devices, the necessity for data transformation from one form to another becomes an unavoidable aspect. One such mathematical tool that is widely used for transforming time and frequency domain signals is Fourier Transform. Fast Fourier Transform (FFT) is perhaps the fastest way to achieve transformation. Many algorithms and architectures have been designed over the years in an attempt to make FFT algorithms more efficient and to target many applications; The main objective of our work is to design, simulate and implement an architecture based on the Twiddle-Factor-Based decomposition FFT …
Design And Control Of A Smart Fin Using Piezoelectric Actuators, Surya Kiran Parimi
Design And Control Of A Smart Fin Using Piezoelectric Actuators, Surya Kiran Parimi
UNLV Retrospective Theses & Dissertations
The objective of this research work is to design and implement control algorithms for smart fin of a projectile, which is currently under development in the Army Research Laboratory (ARL). The smart fin is used to maneuver small aerial vehicles by controlling the rotation angle of the fin. The fin is activated by a composite laminated plate that has two active piezoelectric layers. The prototype of the smart fin is assembled using Macro Fiber Composite (MFC actuator model M8557, Smart Material Co); Control algorithms for rotating the fin when subject to external aerodynamic forces are proposed. These controllers use a …
Joint Design For Shock Mitigation In Vehicles, Jagannadha Rao Naraparaju
Joint Design For Shock Mitigation In Vehicles, Jagannadha Rao Naraparaju
UNLV Retrospective Theses & Dissertations
Propagation of ballistic shock from the region of impact to the locations of critical components can result in human injury and component failure in a combat vehicle, leading to reduced effectiveness of the vehicle and its crew. The armor joints of the ground vehicle can be designed to reduce these possibilities of failure. The objective of the design is to mitigate (absorb/reflect/disrupt, etc.) the incident shock loading and to reduce the acceleration transmitted to specific locations within the vehicle using redesigned joint between structural components that can absorb energy. The purpose of this study is to determine the optimal types …
The Design And Testing Of A Hydrogen Fueled Internal Combustion Engine, Evangeline Bulla
The Design And Testing Of A Hydrogen Fueled Internal Combustion Engine, Evangeline Bulla
UNLV Retrospective Theses & Dissertations
A conventional single cylinder 425 cc four stroke internal combustion Polaris engine has been modified to run on hydrogen gas. For such an effort, both port injection as well as direct injection of hydrogen were attempted on the engine in order to evaluate its performance. The emphasis was placed on using direct injection of hydrogen over port injection, thereby utilizing the benefits of having high potential with regard to power, efficiency and also the minimization of NOx emissions. The engine was tested at Kell's automotive using a specially designed dynamometer for this purpose. Various performance parameters like power, torque, emissions, …
Design Of Fuzzy Logic Based Adaptive Traffic Signal Controller, Murali Mohan Ande
Design Of Fuzzy Logic Based Adaptive Traffic Signal Controller, Murali Mohan Ande
UNLV Retrospective Theses & Dissertations
Traffic control of street intersections is one of the most critical elements in providing an efficient flow of traffic in urban networks. Conventionally, pretimed controllers are used, but they cannot respond to real time fluctuations in traffic demand. Traffic actuated signals provide an improvement over pretimed controllers, but their performance deteriorates under heavy traffic conditions. These conditions necessitate the development of a controller that responds to actual traffic demand in real time, with the objective of minimizing vehicle delays, number of stops, etc. Fuzzy logic provides the potential for development of a system that would address these needs; The objective …
Design-Build Method Viewed By Public Agencies In Southern Nevada Compared To Arizona And Utah, Jose W Oliveira
Design-Build Method Viewed By Public Agencies In Southern Nevada Compared To Arizona And Utah, Jose W Oliveira
UNLV Retrospective Theses & Dissertations
The Las Vegas Metropolitan Area is the fastest growing large urban area in the United States. Between 1990 and 2000, the population expanded 83.3 percent. To meet the growing population in the Las Vegas Valley, local agencies struggle to construct public facilities such as community centers, schools, municipal buildings and transportation facilities. The most common construction contracting method being used by local agencies consists of local municipalities hiring a design professional, usually an architect or engineer, under one contract, and then bidding the construction services out to a general contractor; An innovative form of construction contracting now exist, where only …
The Design And Implementation Of An Input/Output Subsystem For A Farsi Language Search Engine, Ronald L Young
The Design And Implementation Of An Input/Output Subsystem For A Farsi Language Search Engine, Ronald L Young
UNLV Retrospective Theses & Dissertations
The question posed in this thesis is whether it is feasible to use commonly available computer hardware and software equipment found in the United States for querying a web-based native Farsi language search engine. A document conversion utility consisting of a C program called html2unicode was constructed to convert the native language web pages into a common format. A Javascript keyboard application and corresponding embeddable web server was developed to make native Farsi language input and output accessible to a search engine. Although there are some issues inherent in the conversion of Farsi web pages into a format suitable for …