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Variable Structure And Singular Perturbation Control Of Elastic Dynamical Systems, Shailaja Chenumalla

UNLV Retrospective Theses & Dissertations

This thesis treats the question of control of flexible dynamical systems for space applications. Two elastic dynamical systems are considered; The multibody system developed in Phillips Laboratory, Edwards Air Force Base, CA consists of two elastic links actuated by electric motors at the joints and rotate on a smooth horizontal granite table. An air bearing is used, which allows the whole system to float on the air so that the frictional forces do not exist between the support plate and the granite table. The controlled output is judiciously chosen such that the zero dynamics are stable or almost stable. For …

An Estimate Of The Impact That Mega-Resort Casino-Hotels Have On Existing Las Vegas Strip Casino/Hotels, Gregory Wayne Goussak

UNLV Retrospective Theses & Dissertations

The objective of this research paper is to estimate the impact that new mega-resorts have on existing Las Vegas "strip" hotel/casinos; A multiple linear regression equation will be created to determine the impact that new Las Vegas mega-resort properties may have on the gross gaming revenue of existing Las Vegas "strip" casino/hotels; The results of this study found two primary impacts: (1) new mega-resorts did not change the growth rate of gross gaming revenue over an extended period of time and (2) new mega-resorts took a share of the gross gaming revenue resulting in a negative impact on existing Las …

The Effect Of Prophylactic Knee Braces On Running Gait, Charles Lawson Liggett

UNLV Retrospective Theses & Dissertations

The use of prophylactic knee braces to prevent knee injuries in football players might increase the risk of injuries to the players because of changes in normal function. This study focused on one of seven criteria for knee braces developed by the American Academy of Orthopedic Surgeons, namely that a brace should not interfere with normal running function in the lower extremity. Subjects with no prior history of knee injury were filmed while running on a treadmill. Digital analysis of each subject's running gait with and without the use of knee braces was performed. The knee, ankle and hip joints …

Southern Nevada Effluent Wetlands: A Proposed Cooperative Venture Between The Bureau Of Reclamation & City Of Las Vegas, Bureau Of Reclamation

Publications (WR)

Throughout North America there is a growing interest in constructed wetlands, both as relatively inexpensive, low-maintenance systems for removing nutrients from wastewater, and as a means of using municipal wastewater to enhance wildlife habitat and create public use opportunities. Because wetlands appear to have good potential as a component in the overall management of scarce water resources, the Bureau of Reclamation (Reclamation) has undertaken several cooperative research and demonstration projects to evaluate their effectiveness in a variety of local environments. While a number of projects have demonstrated that wetlands can be beneficially employed to improve water quality, few such projects …

Depositional Environments And Paleoecology Of The Lower Ordovician Pogonip Group, Opd Unit, Arrow Canyon Range, Clark County, Nevada, Jeffrey K. Donovan

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Opd Unit of the Pogonip Group is a slope-forming carbonate sequence that crops out in the Arrow Canyon Range 75 miles north of Las Vegas, Nevada. It is composed mainly of grainstones, packstones, and intraformational conglomerates and also contains Calathium-bearing bioherms composed dominantly of wackestones. These rocks were deposited in a shallow-water, high-energy, subtidal, tropical marine environment. Nuia and Nuia-crinoid shoals developed on this shallow ramp and the area was frequently disturbed by storms.

Calathium-dominated carbonate mudmounds emerged on the Nuia and Nuia-crinoid shoals. Although Calathium dominated the mounds on a macroscopic scale, the mounds …

The Impact Of A Water-Imposed Interruption Of Growth In The Las Vegas Region, William T. White, Thomas M. Carroll, R. Keith Schwer

Publications (WR)

This study is prompted by the expectation that water supplies for the Las Vegas Valley, both those used currently and those additional quantities available from existing sources, cannot sustain significant further economic growth of the region beyond the year 2006.

There are five parts to this study. Part I uses a regional econometric (REMI) model to project the growth of the Las Vegas region to natural maturity, essentially unconstrained by an overriding water shortage.

Part II is a reinforcing cross-section analysis of metropolitan areas in the United States to learn the most common natural growth patterns and those that have …

Unlv "Rebels" Vs. Utah State, University Of Nevada, Las Vegas

UNLV Basketball Programs

Team roster for both schools.

UNLV Schedule

List of UNLV Scholarship Donors

Meet the Rebels

Opponent's Scouting Report

Jerry Tarkanian Story

Jerry Tarkanian Tribute

Also contains a Jerry Tarkanian poster

Also contains information on other sports at UNLV

Evidence For Atomic Processes In Molecular Valence Double Ionization, U. Becker, Oliver Hemmers, B. Langer, A. Menzel, R. Wehlitz, W. B. Peatman

Environmental Studies Faculty Publications

Complete molecular valence-electron spectra were measured for CO. Unexpectedly, discrete lines at low kinetic energies were found, superimposed on a continuous energy spectrum representing direct double-ionization processes. The appearance of these lines is discussed in the context of the formation of the C⁺+O⁺ ion pair near its associated threshold at 38.4 eV. It is ascribed to valence-excited repulsive (CO⁺)^* states, which dissociate to a large part rapidly into atomic fragments before electronic relaxation takes place. From our spectra, partial cross sections for the different processes leading to dissociative valence double ionization are derived.

Fire In A Riparian Shrub Community: Postburn Water Relations In The Tamarix-Salix Association Along The Lower Colorado River, S. D. Smith, D. E. Busch

Life Sciences Faculty Research

Higher water potentials in recovering burned salt-cedar (Tamarix ramosissima) relative to unburned plants and the opposite situation in willow (Salix gooddingii) provide evidence that postfire water stress is reduced in the former but not the latter. Similarly, diurnal patterns of stomatal conductance in these taxa are consistent with the existence of more vigor in burned salt-cedar than willow. Plots of water potential and transpiration demonstrate that hydraulic efficiencies may contribute to differences in fire recovery.

Heat Pipe Effect In Porous Medium, Martin Joseph

UNLV Retrospective Theses & Dissertations

In this thesis, a parametric study of the thermal and hydrologic characteristics of the fractured porous tuffs at Yucca Mountain, Nevada was conducted. The effects of different fracture and matrix properties including permeability, thermal conductivity, specific heat, porosity, and tortuosity on heat pipe performance in the vicinity of the waste package were observed. Computer simulations were carried out using TOUGH code on a Cray YMP-2 supercomputer; None of the fracture parameters affected the heat pipe performance except the mobility of the liquid in the fracture. Matrix permeability and thermal conductivity were found to have significant effect on the heat pipe …

The Validity And Reliability Of A 1-Minute Half Sit-Ups Test, Maria Hortensia Diener

UNLV Retrospective Theses & Dissertations

The purpose of this study was to investigate the validity and reliability of a 1-minute half sit-up test to allow for its implementation as a test of abdominal strength and endurance. Subjects (N= 133) performed as many sit-ups as they could in one minute. A test-retest reliability study was conducted for two measuring devices, in which subjects performed the sit-ups twice using the same apparatus. An inter-apparatus reliability study between the two apparatus was conducted, in which subjects performed the sit-ups once for each measuring device. Results showed very high test-retest reliability for both measuring devices and high inter-apparatus reliability. …

Six Adult University Esl Students' Perspectives Of Dialogue Journal Writing: A Multiple Case Study, Vicki L Holmes

UNLV Retrospective Theses & Dissertations

To provide insight into adult university ESL students' perspectives of dialogue journal writing and of their changing views of themselves as writers, a fifteen-week multiple case study was conducted, with student interviews and dialogue journal entries providing the primary sources of data. Grounded in social interactionism and cognitivism, and viewed from the perspectives of the students, this study attempted to add to the growing body of research about dialogue journal writing with speakers of English as a second language; Six ESL students representing five different cultures and ranging in age from 18 to 33 participated in the study. Each participant …

Desorption Hysteresis In Five Ion Exchanged Montmorillonites, Jerry Paul Fairley

UNLV Theses, Dissertations, Professional Papers, and Capstones

It is generally believed that the formation of recalcitrant (slowly desorbing) fractions of volatile organic compounds (VOCs) in soils is due to diffusion of compounds to sorption sites inaccessible to bulk fluid. The exact nature of these sites, however, is not well understood. In clay minerals, researchers favor two probable areas for the storage of persistent contamination; sites between the clay lamella, or sites with clay particle aggregates.

To test the hypothesis that recalcitrant fractions are formed in interlamellar spaces, a Na/Ca Montmorillonite (Smectite) was ion exchanged with five different cations (K⁺, Na⁺, Ca⁺, …

Non-Linear Excitation And Governor Control, Subbarao Venkata Govindaraju

UNLV Retrospective Theses & Dissertations

Modern microprocessor capabilities permit the control designer to consider using relatively complicated nonlinear control algorithms, which would have been considered impractical in the past. This thesis presents the results of a study of the variable structure control and inverse control technique for the design of excitation and governor controllers for a power system. Power systems with a single machine connected to an infinite busbar as well as multimachine systems were considered. Control laws for rotor angle and field flux are derived. The closed loop system is shown to be asymptotically stable. The system can be transferred to a new operating …

Mathematical Modeling, Trajectory And Vibrations Control Of A Three Link Flexible Robot, Satish Jupudi

UNLV Retrospective Theses & Dissertations

The objective of this thesis is to study the dynamics and control of a three link flexible robot. The Lagrange equations are used for deriving the equations of motion of this three link flexible robot. The equations of motion of this robot are derived by using a mathematical and symbolic manipulation software known as MACSYMA. The vibration mode shapes are approximated by using assumed mode method. A PID 'proportional, integral and differential' controller is used in this system to control the input torques to obtain desired joint angles trajectory. Linear stabilizers are introduced to suppress the vibrations of the links …

Spectral Analysis Of Random Number Generators, Christy Juinsuk Olsen

UNLV Retrospective Theses & Dissertations

This paper is based on the theory developed by Dr. Evangelos Yfantis, professor of Computer Science at University of Nevada, Las Vegas. In this paper, we describe a method for testing the fairness of pseudorandom number generators using the Discrete Fourier Transform. We will show how the concept of a random process can be used in a representation for random discrete time signals. Using this concept, we have focused on the mathematical representations of the spectral analysis of a fair pseudorandom number generator. From this representation, a reasonable "spectral" expectation is determined. An algorithm which applies the developed method is …

Sampling Inner Experience In The Learning Disabled Population, Barbara Lynn Schamanek

UNLV Retrospective Theses & Dissertations

The inner experience of four learning disabled individuals and three undiagnosed individuals, ages 24 to 40 years, was investigated using the method of descriptive inner experience sampling (Hurlburt, 1990). This method requires that the subject "freeze" moments of inner experience when signaled by a randomly programmed beeping device, and write down the thoughts, feelings, images and/or other inner experiences occurring at that precise moment. Within 24 hours, the subject met with the experimenter and discussed in detail each sampled moment. The experimenter then prepared descriptions of each sampled moment, which were examined for salient characteristics which emerged from these descriptions. …

Comparison Of Computer Models In Forecasting Hotel And Motel Guestroom Supply, Francois Arnaud Camou

UNLV Retrospective Theses & Dissertations

"Comparison of computer models in forecasting hotel and motel guestroom supply" developed a methodology for estimating guestroom supply. Several traditional forecasting models, including PLAN, were compared. The computer models were applied to Las Vegas, Nevada, using tourism and hospitality statistics from the Las Vegas Convention and Visitors Authority. The purpose of this study was to determine whether these models generate accurate forecasts; which is the most realistic model; and if these model(s) could be used to reduce guestroom overbuilding; First, statistics, from 1972 to 1990, were collected. Second, the primary data were analyzed to determine if any trends existed over …

Model Linkages Between A Hazardous Waste Transportation Impact/Risk Assessment Model And A Transportation Planning Model In A Geographic Information System Environment, Justin Paul Rasas

UNLV Retrospective Theses & Dissertations

Several computer models are currently available that can address portions of nuclear waste transportation analysis. However, no single computer model is currently available to permit an integrated analysis that provides effective graphical display of results and product generation. One model available for analysis related to the transport of hazardous material is Radtran. Radtran requires difficult to obtain data and its outputs are presented in a tabular format. A travel demand model, such as Tranplan, can provide some of the data required for Radtran analysis, but the format of its output is not in a form Radtran can readily use. For …

Shared Comedic Elements Of Three Plays In Modern American Theater: "Six Degrees Of Separation", "I'M Not Rappaport", And "Broadway Bound", Paul S Terry

UNLV Retrospective Theses & Dissertations

This thesis examines three successful American comedy plays which were produced within the last decade. The plays include Herb Gardner's I'm Not Rappaport, which won three Tony awards including best actor and best play for the 1985-86 Broadway season; Neil Simon's Broadway Bound, which premiered on Broadway at the Broadhurst Theatre in December of 1986 to strong reviews; and John Guare's Six Degrees of Separation which opened off-Broadway at the Lincoln Center and was named best new play of the 1990-91 season by the New York Drama Critics Circle; Each of these plays demonstrate both strong comedic and dramatic elements. …

A Sample Selective Linear Predictive Analysis Of Speech Signals, Suresh Kumar Venkata Vishnubhatla

UNLV Retrospective Theses & Dissertations

The Linear Prediction Analysis is one of the popular methods of processing speech. But it has problems in estimating the vocal tract characteristics of voiced sounds uttered by females and children. This is because the conventional linear prediction method assumes that all the sample values in each analysis frame are to be approximated by a linear combination of a definite number of the previous samples whether the previous samples include excitation periods or not. Also, the Linear Prediction analysis is easily affected by source excitation; The vocal tract characteristics of signals of short pitch period can be estimated more accurately …

Reduction And Analysis Of Vla Maps For 281 Radio-Loud Quasars Using The Cray Y-Mp Supercomputer, Ailian Ding

UNLV Retrospective Theses & Dissertations

The thesis reports the reduction and analysis of Very Large Array snapshot observations at 6 cm with the A and C arrays of 192 and 192 + 89 radio sources associated with quasars. The sample includes all of the candidates for the complete samples of radio-loud quasars discussed by Wills and Lynds (1978). The routine reduction included two passes of phase self-calibration. Maps were made with image size of 512 x 512. The A (C) array maps have 0.1 (1.3) arcsec cell sizes, with 0.1 to 0.2 (0.2 to 0.4) mJy/Beam rms noise and dynamic ranges of a few thousand. …

Comparison Of Three Scoring Procedures Within Context-Dependent Item Sets, Pamela Ann Henderson

UNLV Retrospective Theses & Dissertations

It has been theorized and evidenced that traditional reliabilities calculated on tests consisting of context-dependent item sets yield inflated estimates. However, the degree of inflated reliability for different scoring techniques has not been observed. This study scored three context-dependent item sets as stand-alone items and as separate item sets using three different scoring techniques; number-right, polyweighting and the three-parameter IRT logistic model. Differences in reliability estimates for the stand-alone and item set treatment were determined for each scoring procedure and compared. These three scoring procedures were also compared to determine which procedure yielded the highest reliability and validity estimates and …

The Progression Of Photographic Image Manipulation In Communication: An Argument Against The "Revolution" Of Technological Change, Cynthia Lynn Wood

UNLV Retrospective Theses & Dissertations

The technology of photographic image manipulation has evolved faster than our ability to consider its implications. This thesis looks at the recent evolution of image manipulation, which some regard as a "revolution." The various stages of technological progression are examined using examples according to Brian Winston's model of technological change. These stages include: scientific competence, ideation, prototypes, supervening necessity, invention, the 'law' of the suppression of radical potential, and technological performance. A review of literature on the topic of photography in communication is included as well as an examination of the early photographers who used image manipulation in their work. …

Attitudes And Beliefs Of Preservice Elementary School Teachers Towards Mathematics, Deborah Beam Ingalls

UNLV Retrospective Theses & Dissertations

This study purposed to see if measurable changes could be detected in prospective teachers' attitudes or beliefs about mathematics as teachers progressed through their required courses of study in mathematics and mathematics education. The study included 164 prospective elementary school teachers who were enrolled in one of three mathematics or mathematics education courses. The subjects responded to a survey based on common "mathematics myths." The mathematics myths correspond to mathematical beliefs shown in other research to be held by severely math anxious or math avoidant people. The study found that students disagreed more with the mathematics myths as they progressed …

A Post Processing System For Global Correction Of Ocr Generated Errors, Bryan Edward Bullard

UNLV Retrospective Theses & Dissertations

This thesis discusses the design and implementation of an OCR post processing system. The system is used to perform automatic spelling detection and correction on noisy, OCR generated text. Unlike previous post processing systems, this system works in conjunction with an inverted file database system. The initial results obtained from post processing 10,000 pages of OCR'ed text are encouraging. These results indicate that the use of global and local document information extracted from the inverted file system can be effectively used to correct OCR generated spelling errors.

Design And Optimization Of Three-Dimensional Scanning Laser Range Finder, Robert Ben Mcfarland

UNLV Retrospective Theses & Dissertations

The purpose of this project is to develop a technique for minimizing the number of iterations needed to determine the XY&Z position for a laser rangefinding system. Using a Charged Coupled Device (CCD) camera to view a robotic work area a user can select an object on a monitor. A LASER is used to project a beam into the work area and the camera in conjunction with image processing software and hardware is used to locate the LASER spot. The purpose of the research in this paper is to devise techniques to minimize the number of points needed to determine …

Microwave Digestion Methods For Preparation Of Platinum Ore Samples For Icp Analysis, Piotr Nowinski

UNLV Retrospective Theses & Dissertations

The technique of microwave digestion was evaluated as a possible alternative to conventional sample preparation methods for the platinum ores prior to spectroscopic analysis. Microwave energy used with aqua regia in closed vessel provides elevated pressure and rapid heating which significantly reduce digestion time. All analyses were carried out by inductively coupled plasma atomic-emission spectroscopy (ICP-AES). To reduce matrix interferences during analysis, a predigestion step with 50 mL of 1:1 nitric acid was introduced. Both ICP-AES and inductively plasma mass spectroscopy (ICP-MS) were used for analysis of sample extracts. ICP-AES analyses showed improved recoveries of Pd (60-80%) and Pt (30-60%) …

Experimental Dual-Mode Control Of A Flexible Robotic Arm, Woosoon Yim, Jichun Zuang, Sahjendra N. Singh

Electrical & Computer Engineering Faculty Research

This paper focuses on the implementation of a dual-mode controller for the maneuver of a single link flexible robotic arm. The joint angle trajectory tracking is accomplished by a proportional and derivative PD and a feedforward controller. Based on the pole placement technique, a linear stabilizer is designed for elastic mode stabilization. The stabilizer is switched on when the trajectory reaches the vicinity of the terminal state, and the effect of . switching time on arm vibration is investigated. An optical deflection sensor is used for on-line measurements of elastic deflections, and also used for the prediction of the static …

Surface Structure Of √3x√3r 30 Cl/Ni(111) Determined Using Low-Temperature Angle-Resolved-Photoemission Extended Fine Structure, Li-Qiong Wang, Z. Hussain, Z. Q. Huang, A. E. Schach Von Wittenau, Dennis W. Lindle, D. A. Shirley

Chemistry and Biochemistry Faculty Research

A surface structural study of the √3 × √3 R30° Cl/Ni(111) adsorbate system was made using low-temperature angle-resolved photoemission extended fine structure. The experiments were performed along two emission directions, [111] and [110], and at two temperatures, 120 and 300 K. The multiple-scattering spherical-wave analysis determined that the Cl atom adsorbs in the fcc threefold hollow site, 1.837(8) Å above the first nickel layer, with a Cl-Ni bond length of 2.332(6) Å, and an approximate 5% contraction between the first and the second nickel layers (the errors in parentheses are statistical standard deviations only).