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Theses/Dissertations

1998

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Articles 1 - 30 of 329

Full-Text Articles in Physical Sciences and Mathematics

Nickel Subsulfide Can Protect Human Fibroblasts From The Mutagenic Effect Of Benzo[A]Pyrene Diolepoxide, Samir M. Hamdan Dec 1998

Nickel Subsulfide Can Protect Human Fibroblasts From The Mutagenic Effect Of Benzo[A]Pyrene Diolepoxide, Samir M. Hamdan

Masters Theses

Cancer researchers are interested in identifying the environmental causes and synergistic influences of different carcinogens. It is important to examine the combined effect of multiple carcinogens since this is a more realistic representation of the true environmental situation in which we are exposed daily. Our study has reported that pretreating human fibroblasts with nickel subsulfide followed by the simultaneous treatment with both nickel subsulfide and benzo[a]pyrene diolepoxide (BPDE) can protect human fibroblasts from the mutagenic effects of BPDE. These results correlate well with our previous chromium-BPDE co-treatment work, suggesting a transition metal dependent protective effect. This protective effect was dependent …


Synthesis, Characterization And Photophysical Behavior Of A Cr(Iii) Bimetallic System, Yan Chen Dec 1998

Synthesis, Characterization And Photophysical Behavior Of A Cr(Iii) Bimetallic System, Yan Chen

Masters Theses

Many binuclear transition metal complexes have been studied to understand the nature of interactions between the metal centers. People have found Simultaneous Pair Excitation phenomenon in some bimetallic system that can serve as a potential source of Non-Linear Optical behavior.

Thus a series of Cr2 -([14]aneN4)2-X4n+ complexes were synthesized and characterized. Only the cis,cis configuration was found. The results were compared with those of their monomer analogs. The electronic structures are very similar in both monomer and dimer complexes. The quantum yield, UV-Vis absorption and lifetime studies suggested a possible coupling between the …


Separation And Determination Of Monochlorophenols By Capillary Zones Electrophoresis, Zarina Yasmin Banu Dec 1998

Separation And Determination Of Monochlorophenols By Capillary Zones Electrophoresis, Zarina Yasmin Banu

Masters Theses

Chlorine has been widely used in industry. One of the most common uses of chlorine is in municipal water treatment plants. Chlorine reacts with a variety of organic compounds, among these are phenol and its derivatives which are commonly found in natural waters. When these compounds react with chlorine, a variety of chlorine substituted and oxidized products result depending on concentrations, pH, and temperature. In order to study these reactions it is necessary to separate and determine the various products produced.

Earlier studies have shown 3-chloro and 4-chlorophenol cannot be separated by commercial GLC columns. GC/MS (electron impact) measurements cannot …


Three-Dimensional Calculation Of Contaminant Transport In Groundwater At A Dover Afb Site, Tariq O. Hashim Dec 1998

Three-Dimensional Calculation Of Contaminant Transport In Groundwater At A Dover Afb Site, Tariq O. Hashim

Theses and Dissertations

Macroscale rate-limited sorption modeling was tested using a production transport code, the GMS/FEMWATER ground-water modeling package. The code (Version 1.1 of FEMWATER. dated 1 August 1995) was applied to a 3D conceptual model developed from a field site at Dover AFB, DE. A simulation was performed of a 200 hour contaminant injection pulse followed by clean water flushing. A moment analysis performed on the resulting breakthrough curve validated code self-consistency. Another injection pulse simulation showed that retardation temporally delays the breakthrough peak. Transport simulations of pulsed clean water pumping of the test cell with a prescribed initial contaminant distribution demonstrated …


A Portable, Object-Oriented Library For Neural Network Simulation, Martin P. Franz Dec 1998

A Portable, Object-Oriented Library For Neural Network Simulation, Martin P. Franz

Masters Theses

A portable, object-oriented library for simulation of general Multi-layer Feedforward Neural Networks (MLFNs) is described. Unlike all-encompassing neural network simulation environments, the library was designed to allow convenient use in existing programs and in applications where training and testing data are generated using separate, often complex simulations.

The library' s design goals include modularity, portability, efficiency, correctness, compactness, and type-safety. To demonstrate how these objectives are met, competing architectural choices are presented, along with the criteria used for determining the strategy actually implemented. Sample applications using the library are presented, showing how the library' s class files are used in …


Application Of The Paleomagnetic Fold Test To Determine The Relative Timing Of Sill Intrusion And Deformation In The Southwest Helena Salient, Montana, Stephen Christopher Whisner Dec 1998

Application Of The Paleomagnetic Fold Test To Determine The Relative Timing Of Sill Intrusion And Deformation In The Southwest Helena Salient, Montana, Stephen Christopher Whisner

Masters Theses

The Doherty Mountain fold complex is a highly folded and faulted region along the southern boundary of the Helena Salient in southwestern Montana. This region has a complex deformation history that is a key to deformation within the Helena Salient as a whole. A structural interpretation of the deformed rocks of this area was conducted using field mapping and cross section construction at 1:24,000 scale providing insight to the internal deformation processes involved. Fourteen folds and three major faults were mapped and analyzed showing the influence of the Southwest Montana Transverse Zone and late stage detachment faulting on fold orientation. …


Gas Phase Diagnostics Of Cvd Diamond Growth From Chloromethane And Chloroform, James M. Chenault Dec 1998

Gas Phase Diagnostics Of Cvd Diamond Growth From Chloromethane And Chloroform, James M. Chenault

Masters Theses

Low energy electron impact ionization (LEEII) time of flight mass spectrometry (TOFMS) has been used to interrogate gases sampled through an orifice from a diamond growth surface. Methane, chloromethane and chloroform precursor gases were examined to produce electron energy plots of the fragment ions that occur using LEEII. Filament temperature studies were completed covering temperatures from room temperature to over 2000 °C, and the results were compared to the LEEII plots. The monochloromethyl radical has been detected in the experiments using chloroform and the effect of a pretreatment with this radical present has been shown to enhance diamond nucleation. …


A Web-Based Prototype For Afit Edplan Administration, Tien-Chen Lee Dec 1998

A Web-Based Prototype For Afit Edplan Administration, Tien-Chen Lee

Theses and Dissertations

This document details the design, development, and evaluation of a prototype course registration and reporting system for the students and faculty of the United States Air Force Institute of Technology. The web-based system provides HTML-based client interfaces and Active Server Page server processes for interaction with the relational databases used to manage course and personnel data. The system prototype was developed following the "Engineering Software Components for Web-Database Access" methodology of Dipiro. A survey of modern web-based database access techniques is first provided and Dipiro's methodology is reviewed as background. The remainder of the document details the application of the …


Experiments To Maximize Growth In Captive Florida Pompano (Trachinotus Carolinus), Brian J. Hicks Dec 1998

Experiments To Maximize Growth In Captive Florida Pompano (Trachinotus Carolinus), Brian J. Hicks

HCNSO Student Theses and Dissertations

Florida pompano (Trachinotus carolinus) are highly prized food and sport fish indigenous to coastal areas of the southeastern United States. A commercially valuable fishery has historically existed in the Gulf of Mexico and on the South Atlantic seaboard. Efforts to economically culture Florida pompano in a captive environment were only partially successful. Four experiments were performed to explore the physical and environmental requirements of Florida pompano and other closely related species in the Family (Carangidae):

Experiment #1- Semi-natural spawning was induced with newly developed hormonal implants. to initiate and sustain semi-natural spawning in captive Florida pompano. Fish collected from the …


Collisional Effects In The Absorption Spectra Of The Oxygen A Band And Nitric Oxide Fundamental Band, Robert S. Pope Dec 1998

Collisional Effects In The Absorption Spectra Of The Oxygen A Band And Nitric Oxide Fundamental Band, Robert S. Pope

Theses and Dissertations

Fourier transform spectroscopy was used to measure pressure broadening coefficients in the absorption spectra of both the oxygen A band and the nitric oxide fundamental band. Oxygen spectra were recorded with O2, N2, CO, CO2, SF6 and noble gas collision partners, while nitric oxide spectra were recorded using noble gas collision partners. Pressure broadening coefficients were determined in the P and R branches for every resolved line for each of the fifteen collision pairs studied. In addition, broadening coefficients and qualitative evidence of line coupling were found for the Q branch of NO …


Development Of An Operations Research Software Package For Army Divisions., Blane C. Wilson Dec 1998

Development Of An Operations Research Software Package For Army Divisions., Blane C. Wilson

Theses and Dissertations

There exists great potential for applying operations research techniques to solve specific problems in the areas of operations, installation support, and training at the Army division level. Because of the operational tempo of today's active-duty and reserve component units, command must focus on accomplishing the daily missions. Also, due their limited knowledge of the field, planners may not be aware of how operations research can be used to enhance planning and operations. Time, training funds, resources, safety, personnel, and equipment are all critical factors in this process. Operations research techniques could be used to improve division-level operations by saving time, …


Studies On The Occurrence Of Fluoride In Some Food Samples, Taghreed Ali Abdullah Al-Habshi Dec 1998

Studies On The Occurrence Of Fluoride In Some Food Samples, Taghreed Ali Abdullah Al-Habshi

Theses

In recent years, the amount of fluoride in biological samples, drinking water and in fluoride containing food or feedstuffs has generated considerable interest. Hence the determination of fluoride is becoming increasingly important due to its implications for environmental health. Fluoride is considered to be amongst the most phytotoxic of the more common pollutants. In response to that extensive research has been made to improve the determination of trace amounts of fluoride through developing different analytical methods. The application of these various analytical methods for fluoride ion determination in water and food samples has gained an enormous interest.

Chapter I of …


The Simulation, Modeling And Analysis Of Wireless Local Area Networks Supporting The Ieee 802.11 Standard, Jaikwan Joo Dec 1998

The Simulation, Modeling And Analysis Of Wireless Local Area Networks Supporting The Ieee 802.11 Standard, Jaikwan Joo

Theses and Dissertations

Research to improve the performance of the IEEE 802.11 has been ongoing since 1990. The focus of this research has investigated the use of the MAC and Physical layers for improving throughput. An adaptive MAC protocol, CATER (Code Adapts To Enhance Reliability) is based on the proposed MAC standard for wireless local area networks (WLAN)-802. 11. IEEE 802.11 uses a fixed Pseudo-Noise (PN) code for spreading the information signal, implying a fixed process gain at the receiver. When the channel degrades, IEEE 802.11 offers only retransmissions at the MAC layer to contend with the corrupted medium. However, CATER allows communicating …


Development Of Chronoamperometric Logarithmic Signatures With Application To Drug-Package Interactions And Mechanism Elucidation, Beth Sarsfield Dec 1998

Development Of Chronoamperometric Logarithmic Signatures With Application To Drug-Package Interactions And Mechanism Elucidation, Beth Sarsfield

Seton Hall University Dissertations and Theses (ETDs)

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Investigation Of Peptide-Dna Interactions: Synthesis, Characterization And Applications Of Lysyl-Fluorophenylalaninamides, Teresita T. Ortega Dec 1998

Investigation Of Peptide-Dna Interactions: Synthesis, Characterization And Applications Of Lysyl-Fluorophenylalaninamides, Teresita T. Ortega

Seton Hall University Dissertations and Theses (ETDs)

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Uncertainty In Recharge From Subsidence Craters At Frenchman Flat, Nevada Test Site: Impacts Of Initial And Boundary Conditions And Media Properties, David Matthew Ely Dec 1998

Uncertainty In Recharge From Subsidence Craters At Frenchman Flat, Nevada Test Site: Impacts Of Initial And Boundary Conditions And Media Properties, David Matthew Ely

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Nevada Test Site has over 400 subsidence craters formed by the collapse of overlying rock following underground nuclear tests. Under natural conditions, infiltration and recharge would not be considered likely due to infrequent precipitation events and extreme evapotranspiration. Crater U5a in Frenchman Flat was chosen for study because it intercepts significantly more drainage than surrounding craters. Vadose zone modeling was conducted to test the sensitivity of water movement to boundary and initial conditions. The effects of ponding depth was negligible but depth of wetting front movement was highly dependent on the lateral extent of the ponds. The model was …


Essay On Deprivation, Poverty And Well-Being., Diganta Mukherjee Dr. Nov 1998

Essay On Deprivation, Poverty And Well-Being., Diganta Mukherjee Dr.

Doctoral Theses

Issues like inequity, deprivation and poverty have been a focus of interest for social scientists for a long time. The present thesis explores a few aspects of the above issues. It ermbodies the fruit of my intellectual perambulation in the Economic Research Unit of Indian Statistical Institute (ISI) during the years 1995 - 97. The text is divided into six chapters. The first chapter gives a general overview of different aspects of measuring inequality, deprivation and poverty. The second, third and fourth chapters take up the issue of deprivation measurement in detail. They contain discussions on deprivation ordering, indices and …


Stochastic Methods For Evaluating The Potential For Wetland Rehydration In Covered-Karst Terranes, Christian David Langevin Oct 1998

Stochastic Methods For Evaluating The Potential For Wetland Rehydration In Covered-Karst Terranes, Christian David Langevin

USF Tampa Graduate Theses and Dissertations

Augmentation with reclaimed water is one method for rehydrating wetlands damaged by water-level declines. Augmentation with reclaimed water has been proposed for rehydrating a wetland in the covered-karst terrane of west-central Florida. There is concern because reclaimed water may contain harmful agents that could flow from the wetland 1.4 km to a municipal wellfield that withdraws 30,000 m3/day. Estimates of groundwater flow velocities were calculated from the results of detailed field studies at the wetland. Results indicate that groundwater flows downward in the surficial aquifer at rates of 0.1 to 0.2 m/day and horizontally in the Floridan aquifer …


Vegetation Analysis: A Graphical Analysis Of Plant Succession In Desert Communities Affected By Fire, Jeff Lantow Oct 1998

Vegetation Analysis: A Graphical Analysis Of Plant Succession In Desert Communities Affected By Fire, Jeff Lantow

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Mojave Desert is affected by fire every year. With each fire comes the removal of old growth and, in its place, new growth – consisting primarily of those species which thrive in disturbed areas. The focus of my research is to look at plant communities that have been disturbed by fire, and examine the successional pathway of these disturbed environments. The seven environments I analyzed were burned within the last twenty years and are found in the Coleogyne ramosissima ecotone throughout the Spring Mountain range near Las Vegas, Nevada. The data was collected with randomly chosen circle plots in …


Water Conservation In The Las Vegas Valley, Judith M. Keir Oct 1998

Water Conservation In The Las Vegas Valley, Judith M. Keir

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis deals primarily with residential use of water in the Las Vegas Valley, an arid climate located in the Mojave Desert, and whether the education of people living here has any bearing on whether or not they conserve water. Many of the residents of the Las Vegas Valley have moved from other areas of the country, and perhaps are not aware of the fact that there is a limited supply of water available to the Valley. I believe that people are not necessarily wasteful, and that they would want to conserve water, if they were aware that conservation and …


Lead Shot Concentration In Soil At The Overton Wildlife Management Area, Nevada, George R. Bertoty Oct 1998

Lead Shot Concentration In Soil At The Overton Wildlife Management Area, Nevada, George R. Bertoty

UNLV Theses, Dissertations, Professional Papers, and Capstones

During the spring of 1998, soil samples were collected from two areas at the Overton Wildlife Management Area (OWMA), located in the Moapa Valley of Clark County, Nevada. Lead shot has been banned for the hunting of waterfowl since 1986 but is still legal for upland game hunting. Both types of hunting occur at OWMA. One area sampled is a cultivated field and serves primarily as a dove hunting area. The other area is primarily a waterfowl hunting area and is flooded during the waterfowl-hunting season. Lead shot was recovered from 83% of the samples from the dove hunting area, …


A Strategic Analysis Of The Rocky Flats Cleanup, Patrick Mccann Oct 1998

A Strategic Analysis Of The Rocky Flats Cleanup, Patrick Mccann

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Rocky Flats Environmental Technology Site is located in Golden, Colorado. It is situated on 384 acres in a 6,550-acre natural preserve. Rocky Flats ended its original mission in 1989, after raids on the site by both the FBI and the EPA for illegal dumping and other environmental violations. Since then the site has been scheduled for cleanup. This thesis will provide background information on the site and on the company hired to perform the cleanup. It also provides an evaluation of some key policies regarding the cleanup procedures. Since the end of the cold war, the production of nuclear …


Stachybotrys: Is Nevada At Risk?, Terrylynn C. Foley Oct 1998

Stachybotrys: Is Nevada At Risk?, Terrylynn C. Foley

UNLV Theses, Dissertations, Professional Papers, and Capstones

Stachybotrys chartarum (atra) is a toxigenic fungus that is known to adversely impact the health of animals. Until recently, there have only been a few documented clinical reports linking Stachybotrys chartarum to human health effects. Scientists are increasingly convinced that Stachybotrys and its metabolites are responsible for several adverse health effects experienced by people all over the world, although conclusive proof has yet to be established. All the physical requirements needed for indoor Stachybotrys sporulation and growth is provided through water leaks (plumbing, roof or ceiling), flood events, nutrient sources (cellulose and nitrogen), pH, and temperature(23° - 28°C). Stachybotrys has …


Chemical Modification Of Cvd Diamond Electrodes, Robert Matthew Johnson Oct 1998

Chemical Modification Of Cvd Diamond Electrodes, Robert Matthew Johnson

Chemistry & Biochemistry Theses & Dissertations

The micro-array behavior of boron doped CVD diamond thin film electrodes has been studied in acetonitrile containing two redox couples. The analytical technique employed in these studies was cyclic voltammetry. One system is 0.4 mM ferrocene containing 0.1 M tetrabutylammonium hexafluorophosphate (TBAH). This reversible redox system is not only well-known, but also involves only one electron transfer with no breakage/formation of chemical bonds, thus making it a simple system for analysis. The second test is 0.8 mM cobaltocenium hexafluorophosphate, with 0.4 mM ferrocene as an internal standard. Unlike ferrocene, which is neutral initially, cobaltocenium is positively charged, and is reduced …


Influence Of 5'-(Tg)1-3- And 3'-(Ac)1-3-Overhangs On The Thermodynamic And Na+ Binding Properties Of A Series Of Oligonucleotides, Enrique Dilone Oct 1998

Influence Of 5'-(Tg)1-3- And 3'-(Ac)1-3-Overhangs On The Thermodynamic And Na+ Binding Properties Of A Series Of Oligonucleotides, Enrique Dilone

Seton Hall University Dissertations and Theses (ETDs)

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Construction Of Some Combinatorial Designs Arising Out Of Statistical Experiments., Tridib Kumar Dutta Dr. Sep 1998

Construction Of Some Combinatorial Designs Arising Out Of Statistical Experiments., Tridib Kumar Dutta Dr.

Doctoral Theses

Chis dissertation considers construction of two kinds of combi natorial sesigns as used by statisticians: repeated measurements designs (RMDS) and symmetric balanced squares (SBSS). 1.1. REPEATED MEASUREMENTS DESIGNS The researchers need to perform experiments where each experimental unit receives some or all of the treatments in an appropriate sequence over a number of successive periods. These designs are known by several names in the statistical 1iterature: repeated measurements designs, crossover or changeover designs, (multiple) time series designs, and before-after designs. If there are n experimental units 1,2, ... n, t treatments and p periods 0,1, .. .p-1, applied, then an …


Radial Complexity Estimation For Improved Generalization In Artificial Neural Networks, Lemuel R. Myers Jr. Sep 1998

Radial Complexity Estimation For Improved Generalization In Artificial Neural Networks, Lemuel R. Myers Jr.

Theses and Dissertations

When training an artificial neural network (ANN) for classification using backpropagation of error, the weights are usually updated by minimizing the sum-squared error on the training set. As training ensues, overtraining may be observed as the network begins to memorize the training data. This occurs because, as the magnitude of the weight vector, W, grows, the decision boundaries become overly complex in much the same way as a too-high order polynomial approximation can overfit a data set in a regression problem. Since w grows during standard backpropagation, it is important to initialize the weights with consideration to the importance of …


Automatic Target Cueing Of Hyperspectral Image Data, Terry A. Wilson Sep 1998

Automatic Target Cueing Of Hyperspectral Image Data, Terry A. Wilson

Theses and Dissertations

Modern imaging sensors produce vast amounts data, overwhelming human analysts. One such sensor is the Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) hyperspectral sensor. The AVIRIS sensor simultaneously collects data in 224 spectral bands that range from 0.4µm to 2.5µm in approximately 10nm increments, producing 224 images, each representing a single spectral band. Autonomous systems are required that can fuse "important" spectral bands and then classify regions of interest if all of this data is to be exploited. This dissertation presents a comprehensive solution that consists of a new physiologically motivated fusion algorithm and a novel Bayes optimal self-architecting classifier …


A Decision Theoretic Approach For Interface Agent Development, Scott M. Brown Sep 1998

A Decision Theoretic Approach For Interface Agent Development, Scott M. Brown

Theses and Dissertations

The complexity of current software applications is overwhelming users. The need exists for intelligent interface agents to address the problem of increasing taskload that is overwhelming the human user. Interface agents could help alleviate user taskload by extracting and analyzing relevant information, and providing information abstractions of that information, and providing timely, beneficial assistance to users. These agents could communicate with the user through the existing user interface and also adapt to user needs and behaviors. Central to providing assistance to a user is the issue of correctly determining the user's intent. This dissertation presents an effective, efficient, and extensible …


Optimal Atmospheric Compensation For Anisoplanatism In Adaptive-Optical Systems, Matthew R. Whiteley Sep 1998

Optimal Atmospheric Compensation For Anisoplanatism In Adaptive-Optical Systems, Matthew R. Whiteley

Theses and Dissertations

Anisoplanatism in adaptive optics (AO) systems is a performance-degrading effect that arises whenever light from the wave-front sensor beacon and light from the object of interest sample different volumes of optical turbulence. This effect occurs if there is either a spatial separation between the object and the beacon, or a spatial separation between the wave-front sensor and phase-compensation aperture, or if both types of separation are present in the AO system. Anisoplanatism results in an increased value of the aperture-averaged residual phase variance after AO compensation, which causes an exponential decrease in system performance. This dissertation offers a theoretical framework …