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On Evaluating Density Driven Groundwater Flow In The Closed Basin, Aron M Habte Jan 2006

On Evaluating Density Driven Groundwater Flow In The Closed Basin, Aron M Habte

UNLV Retrospective Theses & Dissertations

The hydrogeochemical cycle in the Pilot Valley, a closed basin, is subject to climate variability over a wide range of spatial and temporal scales over long period of time. Saturated and Unsaturated Transport Model (SUTRA) is employed in the Pilot Valley to simulate subsurface and density driven groundwater flow under various climatic and geologic conditions. A Maxey-Eakin method with coupled catchment model, aridity index and incomplete beta function for groundwater recharge distribution is integrated into the SUTRA model for various simulations. A Rayleigh number is used to analyze these circulation patterns of flow under variable climate and geologic conditions. The …

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Numerical Solution Of Boundary Value Problems Using A Variational Formulation, Virendra I Jaiswal Jan 2006

Numerical Solution Of Boundary Value Problems Using A Variational Formulation, Virendra I Jaiswal

UNLV Retrospective Theses & Dissertations

In this thesis unique solutions of certain Boundary Value Problems are approximated by first converting them into their variational formulation and obtaining linear systems of equations by either using finite element method or discretization, then using the Gauss-Seidel iterative method to solve the resulting systems.

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Dynamic Property Characterization Of Ionic Polymer Metal Composite (Ipmc), Prashanth Reddy Duvvuru Kamakshi Jan 2006

Dynamic Property Characterization Of Ionic Polymer Metal Composite (Ipmc), Prashanth Reddy Duvvuru Kamakshi

UNLV Retrospective Theses & Dissertations

In this thesis dynamic properties of Ionic Polymer Metal Composite (IPMC) is studied. The ionic polymer (IPMC) is made out of a high polymer gel film whose surface is plated with platinum. This ionic polymer finds its application in future as artificial muscle. Analytical modeling method for both single and segmented ionic polymer which can exhibit varying curvature along the polymer was introduced. This segmented ionic polymer can generate more flexible propulsion compared with a single strip ionic polymer where only forward propulsion can be generated by a simple oscillatory bending motion. It is well known in biomimetic system research …

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Biometrics In The Hotel Industry: Issues That Impact Customers' Acceptance, Jungsun Kim Jan 2006

Biometrics In The Hotel Industry: Issues That Impact Customers' Acceptance, Jungsun Kim

UNLV Retrospective Theses & Dissertations

Loss from identity theft and related fraud is growing each year. Accordingly, customers are more open to new methods of identification verification. Biometrics, such as fingerprint identification, are good examples of innovative methods to increase not only convenience but also data security and physical security for hotel customers. However, there are concerns about customer behaviors toward this new technology. This study presented current uses of biometrics with special reference to fingerprint technology, addressed customer behaviors toward new technology, and identified factors that impact customer behaviors toward biometrics. Self-administrated questionnaires were provided using the interactive TV survey system of a major …

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Shock Effects On Electronic Components Within A Projectile, Krishna J. V Kuncham Jan 2006

Shock Effects On Electronic Components Within A Projectile, Krishna J. V Kuncham

UNLV Retrospective Theses & Dissertations

Launching a projectile generates severe shocks, which can result in the malfunction of electronic components within the device. The reliability of these components is related to the mode shapes, natural frequencies and the dynamic deflection of the Printed Circuit Boards. Structural vibration analysis of Printed Circuit Boards and their electronic components can be performed using both Finite Element Methods and vibration test. This study presents the effect of shock and the structural response of the electronic components within the projectile. The results are verified by experimental and modal analysis.

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Simulation Of Decomposition Of Sulfur Trioxide Gas On A Self-Catalytic Material, Kiran Kumar Muramalla Jan 2006

Simulation Of Decomposition Of Sulfur Trioxide Gas On A Self-Catalytic Material, Kiran Kumar Muramalla

UNLV Retrospective Theses & Dissertations

This thesis deals with the development of a two-dimensional numerical model to predict the wall-catalyzed homogeneous decomposition of sulfur trioxide gas in tubular component geometry for the production of hydrogen by the sulfur-iodine thermochemical water splitting cycle, a candidate cycle in the U.S. Department of Energy Nuclear Hydrogen Initiative. Cross flow type of heat exchanger concept is chosen for the analysis. The reacting fluid is a mixture of sulfur trioxide gas and water vapor inside the tubes of a heat exchanger. The heat exchanger tubes are made of Incoloy alloy 800H with ALFA-4 coated on the inner walls which acts …

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On Computing Bayesian Credible Sets For The Coefficient Of Variation Of A Normal Population, Skanda Pokkunuri Jan 2006

On Computing Bayesian Credible Sets For The Coefficient Of Variation Of A Normal Population, Skanda Pokkunuri

UNLV Retrospective Theses & Dissertations

The use of Coefficient of Variation (CV) is quite common in many disciplines, yet its estimation has not received much attention from statisticians. In this paper, we consider the problem of confidence interval estimation of CV for a normal population using the Bayesian approach. The method of Gibbs Sampler is used for numerical integration in order to compute the Bayes credible sets for CV for two different joint prior distributions---the natural conjugate prior, and the non-informative prior. Several simulated examples are included to demonstrate the proposed procedure.

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An Analysis Of The Acoustic Doppler Velocimeter In Low Flow Environments Along The Las Vegas Wash, Roslyn Ryan Jan 2006

An Analysis Of The Acoustic Doppler Velocimeter In Low Flow Environments Along The Las Vegas Wash, Roslyn Ryan

UNLV Retrospective Theses & Dissertations

This research project evaluated the performance of the Acoustic Doppler Velocimeter (ADV) in "low flow" environments along the Las Vegas Wash. It also tested the boundaries and limitations of the Acoustic Doppler Velocimeter. Measurements were made using both the ADV and the traditional mechanical Pygmy Meter, which has been the standard for low flow discharge measurements in the United States Geological Survey (USGS) since 1885; The first set of measurements showed that the ADV is just as reliable as the Pygmy Meter when obtaining low flow discharge measurements. The next series of measurements tested the ADV by using a series …

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Shock Isolation Using Magnetorheologically Responsive Technology, Vijayasarathy Subramanian Jan 2006

Shock Isolation Using Magnetorheologically Responsive Technology, Vijayasarathy Subramanian

UNLV Retrospective Theses & Dissertations

The purpose of this thesis is to develop a shock isolation system using magnetorheologically (MR) responsive technology to isolate shock input to various components in the light weight military vehicles susceptible to ballistic shock effects; Two methods are chosen for isolation of the shock. One is the friction damper based on MR fluid and the other is an elastomer based on magnetically responsive elastomer (MRE). Both approaches can be utilized for semi-active control schemes that have been widely used because of its unique feature of using variable damping and stiffness characteristics of the isolator; In this thesis, both computer simulation …

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Uncertainty Analysis: Mid-Term Operational Model For The Lower Colorado River, Shana Goffman Tighi Jan 2006

Uncertainty Analysis: Mid-Term Operational Model For The Lower Colorado River, Shana Goffman Tighi

UNLV Retrospective Theses & Dissertations

Water managers at the U.S. Department of Interior, Bureau of Reclamation as well as other federal and local agencies use a monthly modeling tool called the 24-Month Study as the numerical basis of many decisions along the Lower Colorado River. It is a deterministic model and currently does not provide information about the uncertainty associated with forecasted outputs. As water resource management becomes increasingly based on technical models, managers realize the importance of the ability to understand and quantify uncertainty. This thesis contributes to efforts in this arena by accomplishing the following objectives: (1) identification of the various sources of …

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Design And Evaluation Of Multi-Axis Vibration Shaker Concepts, Brinda Holur Venkatesh Jan 2006

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 …

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Statistical Models For Right-Turn Related Crashes At High Crash Locations In The Las Vegas Valley, Paul John Villaluz Jan 2006

Statistical Models For Right-Turn Related Crashes At High Crash Locations In The Las Vegas Valley, Paul John Villaluz

UNLV Retrospective Theses & Dissertations

The research objective was to develop a statistical model that related right-turn related crashes (RTRC) to volumetric factors at High Crash Locations (HCL) in the Las Vegas Valley. Information from selected HCL was analyzed with simple bivariate regression analysis and multiple regression analysis; Response variables included the number of RTRC, the ratio of RTRC/Million Entering Vehicles (MEV), and the ratio of RTRC/Total Intersection Crashes. Predictor variables included Right-Turn Volume, Right-Turn-On-Red Volume, Red Time/Cycle Time Percentage, Cross Product (per 1000 Vehicles) of Right-Turn Volumes and Opposing Through Volumes [Cross Product], Frequency of Gaps greater than 6.5 seconds [Gaps > 6.5 s], and …

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The Effects Of Local Muscle Fatigue On Shock Attenuation Characteristics During Running, Kaori Teramoto Jan 2006

The Effects Of Local Muscle Fatigue On Shock Attenuation Characteristics During Running, Kaori Teramoto

UNLV Retrospective Theses & Dissertations

The purpose of this study was to examine shock attenuation (SA) characteristics as well as stride characteristics before and after a fatigue protocol of the ankle dorsiflexors while running on a treadmill. Thirteen females (25.4 +/- 3.8 yrs; 63.2 +/- 8.9 kg; 164.3 +/- 3.1 cm) ran at the same (preferred) speed prior to and following bilateral local muscle fatigue of the ankle dorsiflexors. The fatigue protocol consisted of five sets of maximal concentric and eccentric contractions with a 15-second rest between the sets. Accelerometers (1004 Hz) were securely mounted on the distal aspect of the tibia and on the …

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Monitoring Of A Zero Energy House, Sandor Ferenc Rosta Jan 2006

Monitoring Of A Zero Energy House, Sandor Ferenc Rosta

UNLV Retrospective Theses & Dissertations

A comparative study is conducted to measure the actual performance of a Zero Energy House design. Ideally, a zero energy house produces as much energy as it consumes in a year's time. Two identically-sized houses (1610 ft2), constructed side-by-side in southwest Las Vegas, Nevada, are equipped with a network of sensors that measure many aspects of energy usage in each home. One house serves as a baseline (standard comparison) house and was built using conventional construction techniques. The other house, the Zero Energy House, employs many energy saving features, solar power generation, and supplemental solar water heating. Both houses are …

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Development Of An Integrated Process Simulation System Model For Spent Fuel Treatment Facility (Sftf) Design, Matthew S Hodges Jan 2006

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 …

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Permanent Record, Jonathan Bauch Jan 2006

Permanent Record, Jonathan Bauch

UNLV Retrospective Theses & Dissertations

Permanent Record is a collection of loosely connected short stories, told primarily in the first person (framed by a prologue and epilogue in other points of view), taking place on Staten Island; New York, during the 1980s. Tracing the character's development from his bar mitzvah through college, the stories deal primarily with a young man's attempt to reconcile his feelings of rebellion---against his parents, teachers, tradition, etc.---with his growing awareness of the Judaism instilled in him as a child. As much as the character tries to distance himself from his parents and their religious values, he becomes increasingly aware how …

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Bootstrap Estimation Of Standard Error Of Ridge Estimates, Mira Capur Jan 2006

Bootstrap Estimation Of Standard Error Of Ridge Estimates, Mira Capur

UNLV Retrospective Theses & Dissertations

In multiple linear regression (MLR) the parameter estimates based on the method of least squares are typically unsatisfactory if the predictors are highly correlated. Ridge regression proposes a remedy to multicollinearity problems by modifying the method of least squares to allow biased estimation of the regression coefficients. This is a procedure that involves adding a small positive constant to the diagonal elements of X'X before numerically inverting it. The ridge regression method typically yields biased estimates with smaller mean square error. This thesis deals with estimating the standard errors of ridge estimates using bootstrap resampling. With code developed in R …

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Dose Comparison Of Multi-Slice Computed Tomography Scanners, James J Kelley Jan 2006

Dose Comparison Of Multi-Slice Computed Tomography Scanners, James J Kelley

UNLV Retrospective Theses & Dissertations

The rapid technological advances in CT over the past 30 years have resulted in a steady increase in the number of CT scans being performed annually, making it the major source of exposure to the population via diagnostic x-rays. With this increased utilization, the concerns over patient radiation doses from CT have also grown. Although CT studies only amount to about 5% of all X-ray examinations, it contributes approximately 40% of the collective dose from diagnostic radiology to the population. This fact has made CT dosimetry an important topic in diagnostic radiology today. The introduction of multislice scanners has focused …

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An Arima-Model-Based Approach With Hazard Area For The Probability Of Volcanic Disruption Of The Proposed High-Level Radioactive Waste Repositiory At Yucca Mountain, Nevada, Usa, Xiaojuan Liu Jan 2006

An Arima-Model-Based Approach With Hazard Area For The Probability Of Volcanic Disruption Of The Proposed High-Level Radioactive Waste Repositiory At Yucca Mountain, Nevada, Usa, Xiaojuan Liu

UNLV Retrospective Theses & Dissertations

An interesting extension of advanced time-series analysis techniques is introduced into the domain of volcanological data exploration. A new and innovative use of the well-known ARIMA method for modeling the recurrence rate of volcanism ranging from simple Poissonian volcanoes to those showing cyclic trends is presented. Specifically, we propose a new tool to fingerprint the eruptive behavior of a volcano, which also links some modeling tools of two of the most developed areas in the literature of statistics: stochastic processes and time series. Valuable modeling and computing insights are discussed using a data set from the volcanic database at Yucca …

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Adaptive Design Of Delta Sigma Modulators, Gregory Kenneth Lull Jan 2006

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 …

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Tensile Properties, Fracture Toughness And Crack Growth Study Of Alloy C-276, Joydeep Pal Jan 2006

Tensile Properties, Fracture Toughness And Crack Growth Study Of Alloy C-276, Joydeep Pal

UNLV Retrospective Theses & Dissertations

The results of tensile testing involving austenitic Alloy C-276 indicated that this material is capable of maintaining adequate structural strength at temperatures relevant to the H2SO4 decomposition process related to the nuclear hydrogen generation. This alloy exhibited a unique phenomenon known as dynamic strain aging, which has been studied as a function of both temperature and strain rate. An average value of 55 KJ/mole has been determined to be the activation energy for plastic deformation under tensile loading at different temperatures. Increased crack extension was observed in wedge-loaded double-cantilever-beam specimens exposed to an acidic solution and subjected to higher initial …

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Robust Speaker Identification Using Artificial Neural Networks, Madhavan Sivathanu Pillai Jan 2006

Robust Speaker Identification Using Artificial Neural Networks, Madhavan Sivathanu Pillai

UNLV Retrospective Theses & Dissertations

This research mainly focuses on recognizing the speakers through their speech samples. Numerous "Text-Dependent" or "Text-Independent" algorithms have been developed by people so far, to recognize the speaker from his/her speech. In this thesis, we concentrate on the recognition of the speaker from the fixed text i.e. "Text-Dependent". Possibility of extending this method to variable text i.e. "Text-Independent" is also analyzed. Different feature extraction algorithms are employed and their performance with Artificial Neural Networks as a Data Classifier on a fixed training set is analyzed. We find a way to combine all these individual feature extraction algorithms by incorporating their …

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Statistical Modeling Via Empirical Recurrence Rate, Hui Wang Jan 2006

Statistical Modeling Via Empirical Recurrence Rate, Hui Wang

UNLV Retrospective Theses & Dissertations

A key parameter, most sought after by the modelers of reliability, is the failure rate of a targeted repairable system. Popular modeling techniques based on a point process such as the Power-law process often are handicapped by the requirement of a monotonic failure rate. In this thesis, we show the potential of building a linking bridge between the traditional homogeneous and nonhomogeneous Poisson processes and the classical time series via a sequence of the empirical recurrence rates, calculated at equally spaced intervals of time. The distinctive signature, marking the unique failure pattern of a repairable system, is displayed with an …

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Answers The Dog Whispered, Allison Marie Wilkins Jan 2006

Answers The Dog Whispered, Allison Marie Wilkins

UNLV Retrospective Theses & Dissertations

A woman writing must learn to fuse all of her identities in order to be true to herself and her writing. She must think about the issues that affect all women, and then she must decide how to handle them herself. These issues are what make up the body of poetry in "Answers the Dog Whispered". The poems are about answering the questions that life asks of a woman; The poems range in topic from motherhood to grief, erotic love to family, relationships to writing. Their common unifying theme is a strong woman's voice that pushes the boundaries between the …

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Literature Based Discovery: Techniques And Tools, Ramalakshmi Sundar Jan 2006

Literature Based Discovery: Techniques And Tools, Ramalakshmi Sundar

UNLV Retrospective Theses & Dissertations

Literature Based Discovery (LBD) was initially proposed by Don R. Swanson in 1980 as a method to establish relationships between disease and remedy from disjoint science literature. Consequently, he established a link between magnesium and migraines. Since then literature based discovery has been a subject of research and development for discovery in online medical publications. It has further been investigated in both chemistry and mathematics; In this thesis, we give an overview of LBD and the software tools necessary to automate this technique. We further provide an implementation of this technique that is intended to be used for computer science …

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Application Of Computational Fluid Dynamics For High Energy Efficiency Design With Human Comfort Of Cad-Vav And Ufad Systems, Bhanu Rekha Bandhakavi Jan 2006

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 …

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Arima Models For Forecasting Poisson Process Observations: Application To The Volcanoes Worldwide, Heng-Wei Cheng Jan 2006

Arima Models For Forecasting Poisson Process Observations: Application To The Volcanoes Worldwide, Heng-Wei Cheng

UNLV Retrospective Theses & Dissertations

A nonhomogeneous Poisson process (NHPP) is often appropriate for the modeling of a series of events that occur over time in a nonstationary fashion. A major difficulty with the NHPP is that it has infinitely many forms for the intensity function. In this thesis, we propose a linking bridge between a point process and the classical time series via a sequence of the empirical recurrence rates (ERR), calculated sequentially at equidistant time intervals. The distinctive technique is demonstrated with an ERR-plot, designed to fingerprint the temporal pattern of a point process. Moreover, Autoregressive Integrated Moving Average (ARIMA) models are presented …

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Analysis And Evaluation Of Field Retroreflectivity Performance Of Pavement Marking Materials At Various Test Deck Locations In The Us, Siddharth David Jan 2006

Analysis And Evaluation Of Field Retroreflectivity Performance Of Pavement Marking Materials At Various Test Deck Locations In The Us, Siddharth David

UNLV Retrospective Theses & Dissertations

Pavement markings are one of the most important elements of traffic control on roadways. They are lines used on a roadway to warn and direct drivers and to control traffic operations on highways and streets. Pavement markings are typically white and yellow in color depending on usage. Different types of materials are used in the manufacture of pavement markings, including paint, tape, epoxy, thermoplastic, and preformed thermoplastics. Performance measures used to evaluate pavement markings include retroreflectivity, color, and durability; In the US, the National Transportation Product Evaluation Program (NTPEP), administered by the American Association of State Highway and Transportation Officials …

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Environmental Factors Affecting Retention And Graduation In Mlt /Clt Programs, Patricia R Castro Jan 2006

Environmental Factors Affecting Retention And Graduation In Mlt /Clt Programs, Patricia R Castro

UNLV Retrospective Theses & Dissertations

The quality of education delivered to medical laboratory technician/clinical laboratory technician (MLT/CLT) students has been an evolving concern for the clinical laboratory sciences profession. This situation prompted consideration of various factors in MLT/CLT education to determine if student/program characteristics affected student performance; Principles extracted from Alexander Astin's Input-Environment-Output (I-E-O) model were used as a foundation for considering the factors that affect MLT/CLT program student outcomes. Input, environmental, and outcome variables related to MLT/CLT programs were identified for study; A literature review was conducted to gather information relevant to the development of clinical laboratory science practice and education, curriculum development and …

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Voices From Two Sides Of The Atlantic: A Multiple Case Study Of Women's Leadership, Eva Anneli Adams Jan 2006

Voices From Two Sides Of The Atlantic: A Multiple Case Study Of Women's Leadership, Eva Anneli Adams

UNLV Retrospective Theses & Dissertations

People learn and adopt cultural values through socialization. "Voices from Two Sides of the Atlantic" is a multiple-case study about the influence of national socialization on women's leadership experiences. The main research question of the study was: Does national enculturation impact how women lead, and if so, how is it reflected in participants' responses?;This study examined leadership experiences of three Finnish and three American women. It investigated how the participants associate their values with their leadership experience and how they perceive the social context in which they grew up influences leadership. The theoretical framework of the study was based on …

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