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Articles 3421 - 3450 of 3639

Full-Text Articles in Physical Sciences and Mathematics

Wide-Area Incident Management System On The Internet, Kaan Ozbay, Pushkin Kachroo Oct 1998

Wide-Area Incident Management System On The Internet, Kaan Ozbay, Pushkin Kachroo

Electrical & Computer Engineering Faculty Research

The incident management process consists of four sequential steps-incident detection, response, clearance and recovery. Each of these components comprises of a number of operations and coordinated decision-making between the agencies involved. The provision of computer based support tools for the personnel involved will help develop appropriate strategies and increase efficiency and expediency. Existing systems are developed on various traditional computing platforms. However, with the advent of World Wide Web and Internet based programming tools such as Java, it is now possible to develop platform independent decision support tools for the incident management agencies. Any agency will be able to use …


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 Teachers Guide: The Basic Characteristics Of Wetlands And Why They Are Important To The Environment, Charles W. Fisher May 1998

A Teachers Guide: The Basic Characteristics Of Wetlands And Why They Are Important To The Environment, Charles W. Fisher

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this thesis is to develop an educational guide about wetlands that can be used by 3rd- 12th grade teachers. This guide will enable students to learn about wetlands and why they are important to our environment. I will provide examples and a series of activities that teachers can use in the classroom to help their students better understand the benefits and function of wetlands.


The Price Of Clean Air: A Consideration Of Market Based Emissions Trading, Mark W. Miller May 1998

The Price Of Clean Air: A Consideration Of Market Based Emissions Trading, Mark W. Miller

UNLV Theses, Dissertations, Professional Papers, and Capstones

Traditional regulatory approaches for environmental protection do not consider

the costs and benefits of the standards they impose. Further, imposing strict performance

standards on firms with heterogeneous control costs leads to an inefficient allocation of resources devoted to pollution control. This paper explores the use of emission allowance trading as a way to improve economic efficiency within the context of environmental protection. PM10 air pollution from sources within the Las Vegas Valley is used as the case study.

This paper found that an emission trading

program in this particular case study would not live up to the theoretical expectations. Although, …


Effects Of Oxygen Variation On The Ecology Of Devil's Hole, Death Valley National Park, Norma J. Azad Apr 1998

Effects Of Oxygen Variation On The Ecology Of Devil's Hole, Death Valley National Park, Norma J. Azad

UNLV Theses, Dissertations, Professional Papers, and Capstones

The inability to rear Devil's Hole pupfish, Cyprinodon diabolis Wales, in captivity, when captive propagation has been successful with other species of pupfish, led to the examination of environmental factors which are unique to Devil's Hole. It has been suggested that C. diabolis regularly experience developmental arrest due to hypoxic conditions. This arrest may be reversible in areas of the shallow shelf during periods of photosynthetic activity. Oxygen measurements over the shallow shelf reveal a gradient of oxygen variation with the greatest diel variability over the inner portion of the shelf diminishing to nearly imperceptible diel variation toward the outer …


Watercraft Impact On The Lake Mead National Recreational Area, Terence Lino Apr 1998

Watercraft Impact On The Lake Mead National Recreational Area, Terence Lino

UNLV Theses, Dissertations, Professional Papers, and Capstones

No abstract provided.


A Comparison Of Astm Standard E1599-94 And A Site Assessment Project Located In North Las Vegas, Kenneth Anthony Katsuda Apr 1998

A Comparison Of Astm Standard E1599-94 And A Site Assessment Project Located In North Las Vegas, Kenneth Anthony Katsuda

UNLV Theses, Dissertations, Professional Papers, and Capstones

This document provides a comparison of ASTM E-1599-94 Standard for a petroleum release and the procedures performed on a site assessment project in North Las Vegas. The major elements of a site assessment are thoroughly discussed in this document. They elements consist of the Initial Site Assessment, On-Site Delineation, Off-Site Delineation, Sampling/Analysis, and Site Assessment Methodologies.

The data was obtained through extensive research, utilizing reference documents,on-site experience, and the knowledge of Keith Stewart of Stewart Environmental.

After reviewing and comparing the data of my research, the procedures applied to the North Las Vegas Site (NLVS) were quite similar to the …


Neutral Dissociation Of Hydrogen Following Photoexcitation Of Hcl At The Chlorine K Edge, D. L. Hansen, J. Cotter, G. R. Fisher, K. T. Leung, R. Martin, Paul Neill, Rupert C. Perera, I. A. Sellin, Marc Simon, Y. Uehara, B. Vanderford, S. B. Whitfield Apr 1998

Neutral Dissociation Of Hydrogen Following Photoexcitation Of Hcl At The Chlorine K Edge, D. L. Hansen, J. Cotter, G. R. Fisher, K. T. Leung, R. Martin, Paul Neill, Rupert C. Perera, I. A. Sellin, Marc Simon, Y. Uehara, B. Vanderford, S. B. Whitfield

Chemistry and Biochemistry Faculty Research

Time-of-flight mass spectroscopy was used to study the relaxation dynamics of HCl following photoexcitation in the vicinity of the Cl K edge (~2.8 keV) using monochromatic synchrotron radiation. At the lowest resonant excitation to the 6ơ* antibonding orbital, almost half of the excited molecules decay by emission of a neutral H atom, mostly in coincidence with a highly charged Cln1 ion. The present work demonstrates that neutral-atom emission can be a significant decay channel for excited states with very short lifetimes (1 fs). [S1050-2947(98)03604-X]


Double Photoionization Of Helium, James A.R. Samson, Wayne C. Stolte, Z. X. He, Y. Lu, J. N. Cutler, R. J. Bartlett Mar 1998

Double Photoionization Of Helium, James A.R. Samson, Wayne C. Stolte, Z. X. He, Y. Lu, J. N. Cutler, R. J. Bartlett

Chemistry and Biochemistry Faculty Research

The cross sections for double photoionization of helium and the ratios of double to single ionization have been measured from the double-ionization threshold to 820 eV. The results are in very good agreement with several recent calculations.


The Migration Of Arsenic And Lead In Surface Sediments At Three Kids Mine Henderson, Nevada, Douglas Brian Sims Dec 1997

The Migration Of Arsenic And Lead In Surface Sediments At Three Kids Mine Henderson, Nevada, Douglas Brian Sims

Publications (WR)

This study focused on the distribution of arsenic and lead in surface sediments at Three Kids Mine in Henderson, Nevada. The mine site encompasses approximately 470 acres of desert and is situated above two developing communities (Lake Las Vegas and Calico Ridge) and the Las Vegas Valley's water source (Lake Mead).

Transport of arsenic and lead appears to have occurred within a limited range in both the eastern and western washes on the eastern and western sides of Three Kids Mine. Concentrations of arsenic range between 20 mg/kg (ppm) and 1130 mg/kg and between 20 mg/kg and 8400 mg/kg for …


A Plan For Characterizing Waste For The Defense Special Weapons Agency At The Nevada Test Site, Tiffany A. Hatcher Dec 1997

A Plan For Characterizing Waste For The Defense Special Weapons Agency At The Nevada Test Site, Tiffany A. Hatcher

UNLV Theses, Dissertations, Professional Papers, and Capstones

In 1976, Congress adopted the Resource Conservation and Recovery Act (RCRA) to govern hazardous waste. The Act was amended in 1984 with the Hazardous and Solid Waste Amendments in order to further define the requirements of RCRA. RCRA is meant to protect human health and the environment from the effects of hazardous waste, promote waste minimization, and encourage material recycling and recovery. For this purpose, regulations are implemented that cover every aspect of the hazardous waste problem, including generation, transport, treatment, storage, and disposal.

Generators of waste are the most important part of this chain. As defined in RCRA, a …


Public Participation Program Development: An Analysis Of Public Participation In The Water Industry, Marcia Lynne Holmberg Dec 1997

Public Participation Program Development: An Analysis Of Public Participation In The Water Industry, Marcia Lynne Holmberg

UNLV Theses, Dissertations, Professional Papers, and Capstones

The field of public participation is a distinct, but yet unpolished facet within the public relations industry. While the purpose of and need for public participation are becoming increasingly clear, many remain unaware or unconvinced of its advantages. Likewise, even among those who endorse the necessity of public participation, its methods and strategies continue to be a mystery to most.

One industry, in particular, that has recognized and embraced the benefits of conducting public participation is the water utility industry. The purpose of this thesis is to 1) crystallize the understanding of why public participation is a necessary and advantageous …


Volcanology And Geochemistry Of Pliocene And Quaternary Basalts On Citadel Mountain, Lunar Crater Volcanic Field, Pancake Range, Nevada, Loretta D. Dickson Dec 1997

Volcanology And Geochemistry Of Pliocene And Quaternary Basalts On Citadel Mountain, Lunar Crater Volcanic Field, Pancake Range, Nevada, Loretta D. Dickson

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alkali basalts on Citadel Mountain form the southern margin of the Lunar Crater Volcanic Field (LCVF) in the central Great Basin, Nevada. Citadel Mountain comprised of a faulted, north tilted section of Tertiary andesite and ash-flow tuff is capped by Pliocene and Quaternary alkali basalt flows that erupted from six major cinder cones. The basalt flows on Citadel Mountain can be divided into two groups (older and younger) based on age and isotopic signatures. The older basalt group is characterized by higher 87 Sr/86Sr and lower ENd and the younger group has lower 87Sr/86Sr …


Simulation Study Of Learning Automata Games In Automated Highway Systems, Cem Unsal, Pushkin Kachroo, John S. Bay Nov 1997

Simulation Study Of Learning Automata Games In Automated Highway Systems, Cem Unsal, Pushkin Kachroo, John S. Bay

Electrical & Computer Engineering Faculty Research

One of the most important issues in Automated Highway System (AHS) deployment is intelligent vehicle control. While the technology to safely maneuver vehicles exists, the problem of making intelligent decisions to improve a single vehicle’s travel time and safety while optimizing the overall traffic flow is still a stumbling block. We propose an artificial intelligence technique called stochastic learning automata to design an intelligent vehicle path controller. Using the information obtained by on-board sensors and local communication modules, two automata are capable of learning the best possible (lateral and longitudinal) actions to avoid collisions. This learning method is capable of …


The Use Of Spectrofluorimetry And Capillary Electrophoresis/Laser-Induced Fluorescence For The Detection Of Fluorescent Dyes In Groundwater Migration Studies, Patrick Ferguson Oct 1997

The Use Of Spectrofluorimetry And Capillary Electrophoresis/Laser-Induced Fluorescence For The Detection Of Fluorescent Dyes In Groundwater Migration Studies, Patrick Ferguson

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis involves work that was accomplished during a two-year internship at the Environmental Protection Agency's (EPA), Environmental Chemistry Branch. The research is an application of trace level determination of fluorescein dyes used as groundwater tracers. The work was performed to determine whether groundwater could migrate from a Resource Conservation Recovery Act (RCRA) site to an adjacent Superfund site. The research involved using Spectrofluorimetry and a new technique called capillary electrophoresis/laser induced fluorescence (CE/LIF) to determine tracer dyes that were injected at the RCRA site and monitored at the Superfund site. Results from Spectrofluorimetry were compared to those of CE/LIF. …


Aspects Of Postcollision Interactions (Pci) Near The Ar L-Shell, James A.R. Samson, Y. Lu, Wayne C. Stolte Oct 1997

Aspects Of Postcollision Interactions (Pci) Near The Ar L-Shell, James A.R. Samson, Y. Lu, Wayne C. Stolte

Chemistry and Biochemistry Faculty Research

In the present work we are interested in near-threshold photoionization experiments involving postcollision effects related to the Auger decay of a vacancy in the Ar L shell. In particular, we have measured the photoelectron energy spectrum resulting from the above postcollision interaction effects and have observed electrons produced by the process of electron capture and reemission.


Nondipole Resonant X-Ray-Raman Spectroscopy: Polarized Inelastic Scattering At The K Edge Of Cl2, J. D. Mills, J. A. Sheehy, T. A. Ferrett, S. H. Southworth, R. Mayer, Dennis W. Lindle, P. W. Langhoff Jul 1997

Nondipole Resonant X-Ray-Raman Spectroscopy: Polarized Inelastic Scattering At The K Edge Of Cl2, J. D. Mills, J. A. Sheehy, T. A. Ferrett, S. H. Southworth, R. Mayer, Dennis W. Lindle, P. W. Langhoff

Chemistry and Biochemistry Faculty Research

Experimental and theoretical studies are reported on the inelastic (Raman) scattering of wavelength-selected polarized x rays from the K edge of gas-phase chlorine molecules. The polarized emission spectra exhibit prominent nondipole features consequent of phase variations of the incident and emitted radiation over molecular dimensions, as predicted by the Kramers-Heisenberg scattering formalism. Issues pursuant to the detection of core-hole localization by resonant Raman scattering from homonuclear diatomic molecules are critically examined. [S0031-9007(97)03486-8]


Breakdown Of The Independent Particle Approximation In High-Energy Photoionization, E. W. B. Dias, H. S. Chakraborty, P. C. Deshmukh, S. T. Manson, Oliver Hemmers, P. Glans, D. Hansen, H. Wang, S. B. Whitfield, Dennis W. Lindle, R. Wehlitz, Jon C. Levin, I. A. Sellin Jun 1997

Breakdown Of The Independent Particle Approximation In High-Energy Photoionization, E. W. B. Dias, H. S. Chakraborty, P. C. Deshmukh, S. T. Manson, Oliver Hemmers, P. Glans, D. Hansen, H. Wang, S. B. Whitfield, Dennis W. Lindle, R. Wehlitz, Jon C. Levin, I. A. Sellin

Environmental Studies Faculty Publications

The independent particle approximation is shown to break down for the photoionization of both inner and outer nℓ (ℓ>0) electrons of all atoms, at high enough energy, owing to interchannel interactions with the nearby ns photoionization channels. The effect is illustrated for Ne 2p in the 1 keV photon energy range through a comparison of theory and experiment. The implications for x-ray photoelectron spectroscopy of molecules and condensed matter are discussed.


Estimation Of Groundwater Velocities From Yucca Flat To The Amargosa Desert Using Geochemistry And Environmental Isotopes, Ronald L. Hershey, Steve Y. Acheampong Jun 1997

Estimation Of Groundwater Velocities From Yucca Flat To The Amargosa Desert Using Geochemistry And Environmental Isotopes, Ronald L. Hershey, Steve Y. Acheampong

Publications (WR)

Geochemical modeling techniques were applied to groundwater flowpaths from Yucca Flat on the Nevada Test Site (NTS) to the Amargosa Desert, south of the NTS to estimate groundwater flow velocities for independent comparison to velocities calculated by other methods. The groundwater flowpaths examined considered flow in the carbonate aquifer beneath Yucca and Frenchman flats mixing with flow from carbonate aquifers east and southeast of the NTS and discharging at wells south of the NTS border. The approach used the computer codes WATEQ4F and NETPATH to calculate chemical speciation, determine the saturation state of mineral phases, and simulate mixing and the …


Artificial Recharge In The Las Vegas Valley: An Operational History, Michael Johnson, Erin Cole, Kay Brothers, Las Vegas Valley Water District Jun 1997

Artificial Recharge In The Las Vegas Valley: An Operational History, Michael Johnson, Erin Cole, Kay Brothers, Las Vegas Valley Water District

Publications (WR)

Artificially recharging the Las Vegas Valley (Valley) ground-water system with treated Colorado River water is one water resource management option employed by the Las Vegas Valley Water District (District) to help meet future long-term and short-term peak water demands. The District began operation of an artificial ground-water recharge program in 1988 in order to bank water for future use and to slow declining water levels. Artificial recharge occurs in the winter months, typically from October to May, when there is excess capacity in the Southern Nevada Water System (SNWS), currently a 400 Million Gallon per Day (MGD) treatment and transmission …


Blm Rangeland: Has The Condition Improved?, Angela C. Dudley May 1997

Blm Rangeland: Has The Condition Improved?, Angela C. Dudley

UNLV Theses, Dissertations, Professional Papers, and Capstones

"Whose Home Is the Range, Anyway?: The latest research is confirming that in the West's fragile public lands, cattle are often bad news for wildlife." This is the title and headline of Lisa Drew's article in the December/January 1994 issue of National Wildlife. It shows a picture of what looks like a wasteland with only cattle, manure and a fence, no vegetation (Drew, 1994). Inside the article, Drew quotes biologist Bob Ohmart at Arizona State University's Center for Environmental Studies as saying, "Livestock grazing is without a doubt the greatest threat to western wildlife" (p. 15). Drew contends that, "The …


Las Vegas Wash Water Quality Monitoring Program: 1996 Report Of Findings, Richard A. Roline, James J. Sartoris, U.S. Bureau Of Reclamation, U.S. Geological Survey Apr 1997

Las Vegas Wash Water Quality Monitoring Program: 1996 Report Of Findings, Richard A. Roline, James J. Sartoris, U.S. Bureau Of Reclamation, U.S. Geological Survey

Publications (WR)

Las Vegas Wash, a natural wash east of the city of Las Vegas, Nevada, carries stormwater, groundwater drainage, and sewage effluent from three sewage treatment plants to Lake Mead. The Wash provides nearly the only surface water outlet for the entire 2,193 mi2 of Las Vegas Valley. A drainage area of 1,586 mi2 contributes directly to the Wash through surface flow which is channeled to Las Vegas Bay of Lake Mead, while drainage of the remaining 607 mi2 is presumably subsurface and may drain toward Las Vegas Wash.

In the 1930's and 1940's, sewage treatment plants were …


The Eldorado Landfill: A Case Study, Heather A. Nash Apr 1997

The Eldorado Landfill: A Case Study, Heather A. Nash

UNLV Theses, Dissertations, Professional Papers, and Capstones

In 1995, Boulder City bought from the federal government 167 square miles of land in the Eldorado Valley which is located approximately seven miles west of the city. Soon afterward, the current landfill in Boulder City began accepting construction waste from Las Vegas. The large dump trucks had to travel through Boulder City on route to the landfill. In doing this they passed through three school zones and residential areas. When residents began complaining about the trucks, the Boulder City City Council began investigating various ways to solve the problem. The solution they adopted was to construct a new landfill …


Critical Evaluation Of The Double Tracks Remediation Project, Craig J. Barnes Apr 1997

Critical Evaluation Of The Double Tracks Remediation Project, Craig J. Barnes

UNLV Theses, Dissertations, Professional Papers, and Capstones

The U.S. Atomic Energy Commission (AEC) (now the U.S. Department of Energy), in testing the safety of nuclear weapons under many different conditions, detonated single plutonium bearing devices in such a fashion as to simulate an unintentional detonation of the high-explosive portion of nuclear weapons. This resulted in the uncontained spread of plutonium and other radionuclides, such as americium and depleted uranium, in the environment in the vicinity of these experiments. The Double Tracks site was one of these experiments on the Tonopah Test Range (TTR) which was contaminated hi excess of 200 picocuries per gram (pCi/g). The Double Tracks …


Recycling At Work: Waste Reduction And Recycling In The Las Vegas Hospitality Industry, Darlene M. Cartier Apr 1997

Recycling At Work: Waste Reduction And Recycling In The Las Vegas Hospitality Industry, Darlene M. Cartier

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Las Vegas hotel and restaurant industries generate 27% of the total waste for Clark County, Nevada. In an effort to study and increase recycling participation in the hospitality industry, Las Vegas hotels and restaurants were contacted to participate in a collaborative project between UNLV's Department of Environmental Studies and the Clark County Health District's Environmental Health Division, The project involved interviewing establishments with recycling programs currently in place. Information gathered from interviews and program tours was used to develop programs for hotels and restaurants who were not yet recycling. This thesis contains case studies of restaurants and hotels who …


Investigating The Use Of Kalman Filtering Approaches For Dynamic Origin-Destination Trip Table Estimation, Pushkin Kachroo, Kaan Ozbay, Arvind Narayanan Apr 1997

Investigating The Use Of Kalman Filtering Approaches For Dynamic Origin-Destination Trip Table Estimation, Pushkin Kachroo, Kaan Ozbay, Arvind Narayanan

Electrical & Computer Engineering Faculty Research

This paper studies the applicability of Kalman filtering approaches for network wide traveler origin-destination estimation from link traffic volumes. The paper evaluates the modeling assumptions of the Kalman filters and examines the implications of such assumptions.


Feedback Control Solutions To Network Level User-Equilibrium Real-Time Dynamic Traffic Assignment Problems, Pushkin Kachroo, Kaan Ozbay Apr 1997

Feedback Control Solutions To Network Level User-Equilibrium Real-Time Dynamic Traffic Assignment Problems, Pushkin Kachroo, Kaan Ozbay

Electrical & Computer Engineering Faculty Research

A new method for performing dynamic traffic assignment (DTA) is presented which is applicable in real time, since the solution is based on feedback control. This method employs the design of nonlinear H∞ feedback control systems which is robust to certain class of uncertainties in the system. The solution aims at achieving user equilibrium on alternate routes in a network setting.


Composting Landscape Waste From The University Of Nevada, Las Vegas, K. Jill Hammond Mar 1997

Composting Landscape Waste From The University Of Nevada, Las Vegas, K. Jill Hammond

UNLV Theses, Dissertations, Professional Papers, and Capstones

The University of Nevada, Las Vegas is a major producer of organic waste in the Las Vegas Valley. Composting landscape wastes is one way to reduce both landfill dumping and fertilizer costs for the university. It is also an environmentally friendly means of curbing a nationwide problem: unnecessary use of landfill space. Three sites within Clark County were analyzed for the feasibility of composting: Frenchman Mountain, UNLV Campus, and Boulder City Landfill. Using cost analysis, water availability, and other factors to analyze each site, Boulder City Landfill appears to be the best place to house UNLV's composting operation. Composting in …