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Conceptual Models Of Fluid Flow In Fractures, Rajsekhar Reddy Kona

UNLV Retrospective Theses & Dissertations

This thesis is titled "CONCEPTUAL MODELS OF FLOW IN FRACTURES". This thesis study has two parts. In the first part, some conceptual models of fluid flow in fractures will be developed. These models will be used to analyze fluid flow in the near field region of nuclear waste canisters emplaced in fractured rock. Fluid near the canister will evaporate and move into the fractures where it condenses on the walls of the fracture. It is then absorbed by the matrix due to the capillary suction. Then, due to the capillary force, the liquid moves towards the heat source. A region …

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⁺, …

Gender Discrimination And The Future Of Equality, Clotilde Ann Casados Mueller

UNLV Retrospective Theses & Dissertations

Sex discrimination is the hot topic of the 1990's. Key events occurred in 1991 that propelled the issue into America's living rooms. Starting with the passage of the Civil Rights Act of 1991, these events raised new social consciousness on women's rights. Events such as the confirmation of Justice Clarence Thomas, two highly publicized rape trials involving newsmaker-men, and the release of the "glass ceiling" report by the U.S. Secretary of Labor that promised vigorous action against violators of sex discrimination created a new awareness; Also, two new books emerged, one citing the "victimization" of women by men, the media, …

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 …

An Early Childhood Study Of The Water Cycle, Jolynne Taylor Miner

UNLV Retrospective Theses & Dissertations

Young children's understanding of the water cycle was investigated. Sixty children were individually interviewed using the "Survey of Understanding of the Water Cycle." The answers were then scored according to a scale of Four Levels of UnderstanDing A t-test and chi-square test were run. Answers were carefully examined to determine how much young children understand about the water cycle, to see what misconceptions they have about the water cycle, and to compare children's understanding of the water cycle between those children who live in a desert region and those children who live in a mountainous region. The results indicate that …

Factors Affecting Airport Terminal Configuration: An Application And Design For The Future Jerusalem International Airport Terminal, Odeh Saliba Kheir

UNLV Retrospective Theses & Dissertations

Passenger terminals at airports are very critical in terms of their design configuration. The terminal need to be able to meet the increasing passenger demands while maintaining easy circulation. The approach taken for this thesis builds upon considerations of the sequences of passenger flow; This thesis, investigates and analyzes major terminal configurations that have been commonly used in practice. Then it examines four centralized terminal configurations with respect to the average passenger walking distance. It briefly examines the configuration of three existing air terminals in the U.S.A. The three airports are: Sacramento Metro Airport (east terminal), Reno Cannon International Airport, …

The Use Of Jargon In Education, 1920-1990, Susan Lynn Pearson Hollingshead

UNLV Retrospective Theses & Dissertations

The Use of Jargon in Education: 1920-1990 provides a qualitative study based on communication theory was conducted on every issue of selected education journals at ten-year intervals from 1920 to 1990. Ninety preselected vocabulary words were the specific jargon terms evaluated in this study. Content analysis was the methodology for this study. The use of these terms was defined, quantified, tabulated, and graphed and similar terms and/or uses were identified. The ninety preselected vocabulary words were used 12,716 times for all five codes. Code 5 was deleted since it was for a different meaning than the one identified in this …

Integral Action For Chattering Reduction And Error Convergence In Sliding Mode Control, Pushkin Kachroo, Masayoshi Tomizuka

Electrical & Computer Engineering Faculty Research

Sliding mode control is a standard approach to tackle the parametric and modeling uncertainities of a non-linear system. However, the robust control obtained by using sliding mode has a price, which is the high frequency chattering encountered during the digital implementation of the control. The idea of introducing a boundary layer around the switching surface and approximating a continuous control inside it has been extended for different kinds of systems. The systems should be analyzed to ascertain which continuous law is appropriate within the boundary layer. In this paper the effect of various continuous control approximations within the boundary layer …

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).

Electron-Energy And –Angular Distributions In The Double Photoionization Of Helium, R. Wehlitz, Franz Heiser, Oliver Hemmers, B. Langer, A. Menzel, U. Becker

Environmental Studies Faculty Publications

Photoelectron spectra of helium have been measured at different angles and at various energies above the double-ionization threshold up to 120 eV to investigate the behavior of the energy and angular distributions, of shake-off electrons. Both energy and angular distributions clearly show a U-shaped profile which turns to a flat curve near threshold pointing to a uniform intensity distribution over the kinetic energy for all angles in this excitation energy regime. Our results for the angular-distribution asymmetry parameter indicate qualitative agreement with theoretical predictions but fail to provide them quantitatively.

The Sloan Sag: A Mid-Miocene Volcanotectonic Depression, North-Central Mccullough Mountains, Southern Nevada, Hayden L. Bridwell

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the Hidden Valley area of the north-central McCullough Mountains, southern Nevada, mid-Miocene andesite and dacite domes, flows and pyroclastic units (the Sloan volcanics) partially fill a sag in the underlying Hidden Valley volcanics. The 13.5 km diameter sag formed during and/or after the eruption of the Sloan volcanics. Sagging was accommodated by a combination of movement on the McCullough Wash fault system, and subsidence into evacuated chambers.

Major, trace and rare-earth element geochemistry suggests that the rocks of the Sloan volcanics belong to four groups, each of which were produced by partial melting of chemically distinct sources. With the …

Oasis, Schyler Koon, Diane Russell, Lisa Story

UNLV Magazine

No abstract provided.

Measurement Of The Ratio Of Double-To-Single Photoionization Of Helium At 2.8 Kev Using Synchrotron Radiation, Jon C. Levin, Dennis W. Lindle, N. Keller, R. D. Miller, Y. Azuma, N. Berrah Mansour, H. G. Berry, Ivan A. Sellin

Chemistry and Biochemistry Faculty Research

We report the first measurement of the ratio of double-to-single photoionization of helium well above the double-ionization threshold. Using a time-of-flight technique, we find He⁺⁺/He⁺=1.6±0.3% at hν=2.8 keV. This value lies between calculations by Amusia (2.3%) and by Samson, who predicts 1.2% by analogy with electron-impact ionization cross sections of singly charged ions. Good agreement is obtained with older shake calculations of Byron and Joachain, and of Åberg, who predict 1.7%.

Anisotropy Of Polarized X-Ray Emission From Molecules, S. H. Southworth, Dennis W. Lindle, R. Mayer, P. L. Cowan

Chemistry and Biochemistry Faculty Research

Strongly anisotropic, polarized Cl K-V x-ray emission from gas-phase CF₃Cl has been observed following resonant excitation with a linearly polarized x-ray beam. Distinctively different angular distributions are observed for x-ray emission involving molecular orbitals of different symmetries. A classical model of the x-ray absorption-emission process accurately describes the observed radiation patterns.

Female Condoms, An Urgent Need, Mary Guinan

School of Public Health Faculty Research

As of February 1991, more than 16,000 cases of AIDS in women had been reported in the United States, but the ". tidal wave of cases in women is yet to come. World Health Organization (WHO) estimates of the number of women infected with the human immunodeficiency virus (HIV) range from 1.5 million in Africa to I 00,000 in the United States. Within the next ten years, the majority of these women will develop AIDS and die. Some will live a bit longer, but all are eventually doomed to die prematurely. Most will not live to see their 40th year.

Molecular-Orbital Studies Via Satellite-Free X-Ray Fluorescence: Cl-K Absorption And K–Valence-Level Emission Spectra Of Chlorofluoromethanes, Rupert C. Perera, P. L. Cowan, Dennis W. Lindle, R. E. Lavilla, T. Jach, R. D. Deslattes

Chemistry and Biochemistry Faculty Research

X-ray absorption and emission measurements in the vicinity of the chlorine K edge of the three chlorofluoromethanes have been made using monochromatic synchrotron radiation as the source of excitation. By selectively tuning the incident radiation to just above the Cl 1s single-electron ionization threshold for each molecule, less complex x-ray-emission spectra are obtained. This reduction in complexity is attributed to the elimination of multielectron transitions in the Cl K shell, which commonly produce satellite features in x-ray emission. The resulting "satellite-free" x-ray-emission spectra exhibit peaks due only to electrons in valence molecular orbitals filling a single Cl 1s vacancy. These …

The Right To Die: An Old Woman's Formula, Mary Guinan

School of Public Health Faculty Research

On December 26, 1990, Nancy Cruzan died, 12 days after her feeding tube was removed. She had been in an irreversible coma for seven years and her parents had sued for the right to remove the feeding tube that was keeping her alive. The pain and suffering of her family in coming to this decision was certainly compounded by those who disagreed with them and tried to prevent the extubation. Whether one agrees with this particular decision or not, most of us will not be faced with such clear alternatives, ie, leave the tube in or take it out in …

Polarized X-Ray-Emission Studies Of Methyl Chloride And The Chlorofluoromethanes, Dennis W. Lindle, P. L. Cowan, T. Jach, R. E. Lavilla, R. D. Deslattes, Rupert C. Perera

Chemistry and Biochemistry Faculty Research

A new technique sensitive to molecular orientation and geometry, and based on measuring the polarization of x-ray emission, has been applied to the Cl-containing molecules methyl chloride (CH₃Cl) and the chlorofluoromethanes (CF₃Cl, CF₂Cl₂, and CFCl₃) in the gas phase. Upon selective excitation using monochromatic synchrotron radiation in the Cl K-edge (Cl 1s) near-threshold region, polarization-selective x-ray emission studies reveal highly polarized molecular valence x-ray fluorescence for all four molecules. The degree and the orientation of the polarized emission are observed to be sensitive to the incident excitation energy near …

Unlv "Rebels" Vs. University Of California, Santa Barbara And Unlv "Rebels" Vs. New Mexico State, University Of Nevada, Las Vegas

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High-Resolution Photoelectron Spectrometry Study Of Conjugate Shakeup Processes In The Li 1s Threshold Region, B. Langer, J. Viefhaus, Oliver Hemmers, A. Menzel, U. Becker

Environmental Studies Faculty Publications

Partial cross sections and angular-distribution asymmetry parameters of diagram and satellite lines associated with Li 1s photoionization were measured using synchrotron-radiation excitation. Special emphasis was given to a high-resolution study of the ¹P and ³P conjugate shakeup satellite lines testing qualitative predictions of the conjugate shakeup model: increasing σ and decreasing β values towards threshold, both being verified. Comparison with recent relaxed Hartree-Fock calculations shows good agreement for the ¹P satellite, but demonstrates also that the present theory does not seem to be able to describe the cross-section behavior of the ³P satellite correctly.

Fractional Reserve Banking: The Genesis Of Macro-Instability, John Nicholas Koch

UNLV Retrospective Theses & Dissertations

This thesis is a theoretical criticism of fractional reserve banKing The Austrian school (especially the works of Mises, Hayek and Rothbard), consider credit expansion to be the genesis of macro-economic instability; This study applies Austrian interest, capital and business cycle theory to challenge the widely held assumption that our present economic system is fundamentally sound. Using a theoretical construct known as the "Angel Gabriel Model", the devastating consequences of continuing credit expansion are explored. Fractional reserve free banking is also considered within this model and found to be an unsatisfactory option when compared to 100 percent reserve banKing In conclusion, …

Style Of Volcanism And Extensional Tectonics In The Eastern Basin And Range Province: Northern Mohave County, Arizona, Tracey Elaine Cascadden

UNLV Retrospective Theses & Dissertations

The west-dipping Cyclopic-Salt Spring Wash-Lakeside Mine fault system marks the easternmost boundary of the extensional allochthon in the Basin and Range Province and the eastern limit of exposure of mid-Tertiary igneous rocks at the latitude of Lake Mead. The upper plate of this fault system is exposed only in the northern White Hills, Mohave County, Arizona. The upper plate contains east-tilted mid-Tertiary volcanic and sedimentary rocks, cut by down-to-the-west normal faults; Mafic volcanic rocks were erupted from three coeval Miocene volcanic centers. Three distinct types of mafic magma suggest similar degrees of partial melting of different K-rich sources. Each magma …

A New Optimization Approach To The Design Of One-Dimensional And Two-Dimensional Finite Impulse Response Digital Filters, Eddie G Awad

UNLV Retrospective Theses & Dissertations

The theory for designing finite impulse response (FIR) frequency sampling digital filters can be extended to two-dimensions. The linear phase frequency response can be represented as a linear combination of individual frequency responses corresponding to the filter's bands. The design of two-dimensional frequency sampling filters (FSF) has been treated in the past by using the technique of linear programming to find the optimal values of the transition samples. Although in theory the method guarantees an optimal solution, convergence problems occurred; This paper will introduce some detail of a one-dimensional FSF design technique and then extend these concepts to the two-dimensional …

Consideration Of Interdependencies In The Relational Database System, And, A Proposal And Evaluation Of An Expert System For The Relational Database Structure, Timothy Jon Arndt

UNLV Retrospective Theses & Dissertations

This thesis addresses the issue of interdependencies in Distributed and non-Distributed Relational Database Management Systems and proposes a design and development of an Expert System to manage and enhance the current available Database Structures; In the first part, we study, compare and evaluate the interdependencies found in the operating environment relevant to the Distributed Relational structure. Hardware and software configurations are grouped and compared in an attempt to understand the interdependencies of the system so that an optimal configuration may be obtained; In the second part, we designed and developed an Expert System configuration with ease of use and functionality …

Environmental Economics: An Austrian Approach, Fiammetta Elena Zahnd

UNLV Retrospective Theses & Dissertations

This thesis applies Austrian economic theory to environmental goods. It emphasizes capital, interest and entrepreneurial satisfaction of consumer demand for environmental goods. Although provision of several types of environmental goods is mentioned, the final application is to groundwater resources; Both capital and consumer environmental goods must be privately owned and freely exchanged to generate market prices that are used to determine whether capital is being maintained and whether production satisfies consumer demand. Political control wastes resources and causes conflicts. Prior appropriation is the best legal system for recognition of water property titles. Private ownership of water does not preclude cooperation. …

The Effects Of A 12 Week Aerobic Bench Stepping Conditioning Program On Cardiorespiratory Fitness And Muscular Leg Strength In College Women, Sharon Lee Schoff

UNLV Retrospective Theses & Dissertations

The purpose of this investigation was to examine the effects of a 12 week aerobic bench stepping conditioning program on maximum oxygen uptake, time on treadmill and muscular leg strength, measured by knee flexion and extension strength, on college women ranging in age from 18 to 25 years. Prior to a twelve week conditioning period subjects were assessed for maximum oxygen uptake (VO{dollar}\sb2{dollar} max) and time on treadmill (TOT) using a graded treadmill test. Muscular leg strength was measured using Bally's Life Fitness Machines, averaging three maximum knee flexion lifts and extension lifts. These same measurements were repeated following the …

Economic Development, Aid And Debt Crisis In Sub-Saharan Africa, Hassan Ziad Ahmed

UNLV Retrospective Theses & Dissertations

This thesis examines the inverse relationship between foreign capital inflow and domestic savings. The results of the tests lead to a variety of outcomes: (1) There is a positive relationship between the domestic savings ratio and the foreign savings ratio in sub-Saharan African countries. (2) The conclusion from the statistical use of the Chow Test shows that the derived results are reliable results, with the exception of one country, Tanzania. (3) There is no evidence from the cross-sectional study of sub-Saharan Africa to support the negative effect. (4) The performance of the lagged form indicated that the lagged function is …