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1998

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Articles 61 - 90 of 2634

Full-Text Articles in Physical Sciences and Mathematics

Observations On Groundwater Recharge In The Westdale Catchment, M F. Lewis, C E. Mcconnell Dec 1998

Observations On Groundwater Recharge In The Westdale Catchment, M F. Lewis, C E. Mcconnell

Resource management technical reports

A study of the role of groundwater carriers and barriers in controlling salinity was carried out in the Westdale Catchment by Lewis and McConnell (in preparation). Although that study was primarily concerned with groundwater flow and discharge processes, the data collected also provided rudimentary information on the timing of groundwater recharge events and their distribution across the landscape.


Pastoral Resources And Their Management In The Sandstone-Yalgoo-Paynes Find Area, Western Australia, A M E Van Vreeswyk, P. T. Godden Dec 1998

Pastoral Resources And Their Management In The Sandstone-Yalgoo-Paynes Find Area, Western Australia, A M E Van Vreeswyk, P. T. Godden

Agriculture reports

This report covers about 94,700 square kilometres of rangelands in the Sandstone-Yalgoo-Paynes Find area of Western Australia. The area lies within 27°S and 30°S latitudes, and 115°30'E and 120°E longitudes and includes the towns of Sandstone, Yalgoo and Paynes Find. The northern, southern, and eastern limits of the survey area are largely defined by the boundaries of the 1:250,000 scale series map sheets.The western limit is the boundary between the pastoral and agricultural area.


Charge Exchange From D(N = 2) Atoms To Low-Z Receiver Ions, R. Hoekstra, H. Anderson, F. W. Bliek, M. Von Hellermann, C. F. Maggi, Ronald E. Olson, H. P. Summers Dec 1998

Charge Exchange From D(N = 2) Atoms To Low-Z Receiver Ions, R. Hoekstra, H. Anderson, F. W. Bliek, M. Von Hellermann, C. F. Maggi, Ronald E. Olson, H. P. Summers

Physics Faculty Research & Creative Works

To elucidate the influence on charge-exchange spectroscopy of metastable deuterium donors, the corresponding cross sections for state-selective charge transfer have been calculated using the classical trajectory Monte Carlo method. The cross sections for electron capture from D(n = 2) by fully stripped low-Z ions are contrasted with those for capture from ground state D to indicate the importance of metastable donors. Using the new data, effective emission coefficients for the spectral lines of H-like light impurities used in charge-exchange spectroscopy have been calculated. These results incorporate the presence of excited n = 2 donors in the beam and apply to …


Nonanalytic Magnetization Dependence Of The Magnon Effective Mass In Itinerant Quantum Ferromagnets, Dietrich Belitz, Theodore R. Kirkpatrick, Andrew J. Millis, Thomas Vojta Dec 1998

Nonanalytic Magnetization Dependence Of The Magnon Effective Mass In Itinerant Quantum Ferromagnets, Dietrich Belitz, Theodore R. Kirkpatrick, Andrew J. Millis, Thomas Vojta

Physics Faculty Research & Creative Works

The spin-wave dispersion relation in both clean and disordered itinerant quantum ferromagnets is calculated. It is found that effects akin to weak-localization physics cause the frequency of the spin waves to be a nonanalytic function of the magnetization m. For low frequencies Ω, small wave vectors k, and m→0, the dispersion relation is found to be of the form Ω=const x m1-αk2, with α = (4-d)/2 (2 < d < 4) for disordered systems, and α = (3-d) (1 < d < 3) for clean ones. In d = 4 (disordered) and d = 3 (clean), Ωαm ln (1/m) k2. Experiments to test these predictions are proposed.


Fan-Type Conditions For Collapsible Graphs, Zhi-Hong Chen Dec 1998

Fan-Type Conditions For Collapsible Graphs, Zhi-Hong Chen

Scholarship and Professional Work - LAS

No abstract provided.


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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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 …


A Work Minimization Approach To Image Morphing, Peisheng Gao, Thomas W. Sederberg Dec 1998

A Work Minimization Approach To Image Morphing, Peisheng Gao, Thomas W. Sederberg

Faculty Publications

An algorithm is presented for morphing two images, often with little or no user interaction. For two similar images (such as different faces against a neutral background) the algorithm generally can create a pleasing morph completely automatically. The algorithm seeks the minimum work to deform one image into the other, where work is a function of the amount of warping and recoloration. A hierarchical method for finding a minimal work solution is invoked. Anchor point constraints are satisfied by imposing penalties on deformations that disobey these constraints. Good results can be obtained in less than ten seconds for 256 x …


Capillary Zone Electrophoresis Studies Of Sulfur Containing Compounds, Francisco Rodriguez Dec 1998

Capillary Zone Electrophoresis Studies Of Sulfur Containing Compounds, Francisco Rodriguez

Masters Theses & Specialist Projects

Up to this point in time, complex mixtures of tertiary sulfonium ions have been separated or analyzed employing conventional methods like HPLC or NMR procedures. In this thesis the researcher presents a new approach, the use of Capillary Zone Electrophoresis (CZE) for the analysis of these types of ions as well as the closely related thiophenium ions. CZE offers an unprecedented advantage in that separations can be employed for speciation or quantitation of complex mixtures by using the appropriate standards or specific detectors. For the study, model sulfonium and thiophenium ions were used to determine the feasibility of the separation …


A Quantitative Analysis Of Interstitial Fluid-Chemistry And Limestone Dissolution Rates Within The Clastic Sediment Of A Karst Aquifer Conduit, Mammoth Cave, Kentucky, Kevin Vaughan Dec 1998

A Quantitative Analysis Of Interstitial Fluid-Chemistry And Limestone Dissolution Rates Within The Clastic Sediment Of A Karst Aquifer Conduit, Mammoth Cave, Kentucky, Kevin Vaughan

Masters Theses & Specialist Projects

Many active stream conduits within karst aquifers transport and deposit non-carbonate, clastic sediment. However, little is known about how these sediments impact conduit development and enlargement rates. For example, can dissolution take place at the sediment/bedrock interface beneath a flowing stream? If not, cavern enlargement might be dominated by flood conditions when the bare rock of the walls and ceiling are in contact with the dissolving fluids. An approach using limestone tablet weight loss experiments, along with water sampling and geochemical modeling, has been undertaken to understand the nature of fluid movement and chemistry with the sediment beneath an active …


Measurement Of Triple Gauge Wwγ Couplings At Lep2 Using Photonic Events, R. Barate, Manoj Thulasidas Dec 1998

Measurement Of Triple Gauge Wwγ Couplings At Lep2 Using Photonic Events, R. Barate, Manoj Thulasidas

Research Collection School Of Computing and Information Systems

A study of events with photons and missing energy has been performed with the data sample obtained with the ALEPH detector at centre-of-mass energies from 161 to 184 GeV, corresponding to a total integrated luminosity of about 80 pb−1. The measured distributions are in agreement with Standard Model predictions, leading to constraints on WWγ gauge coupling parameters Δκγ and λγ. The results from the fit to the cross sections and to the energy and angular distributions of the photons are: Δκγ=0.05+1.15−1.10(stat)±0.25(syst), λγ=−0.05+1.55−1.45(stat)±0.30(syst).


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 …


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 …


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, …


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 …


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 …


Distribution Of Submerged Aquatic Vegetation In The Chesapeake Bay And Tributaries And The Coastal Bays - 1997, R J. Orth, Judith F. Nowak, David J. Wilcox, Jennifer R. Whiting, Leah S. Nagey Dec 1998

Distribution Of Submerged Aquatic Vegetation In The Chesapeake Bay And Tributaries And The Coastal Bays - 1997, R J. Orth, Judith F. Nowak, David J. Wilcox, Jennifer R. Whiting, Leah S. Nagey

Reports

No abstract provided.


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. …


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 …


Projections Of Alzheimer's Disease In The United States And The Public Health Impact Of Delaying Disease Onset., Ron Brookmeyer, Sarah Gray, Claudia Kawas Nov 1998

Projections Of Alzheimer's Disease In The United States And The Public Health Impact Of Delaying Disease Onset., Ron Brookmeyer, Sarah Gray, Claudia Kawas

Ron Brookmeyer

OBJECTIVES: The goal of this study was to project the future prevalence and incidence of Alzheimer's disease in the United States and the potential impact of interventions to delay disease onset.

METHODS: The numbers of individuals in the United States with Alzheimer's disease and the numbers of newly diagnosed cases that can be expected over the next 50 years were estimated from a model that used age-specific incidence rates summarized from several epidemiological studies, US mortality rates, and US Bureau of the Census projections.

RESULTS: in 1997, the prevalence of Alzheimer's disease in the United States was 2.32 million (range: …


Introduction To Statistical And Probabilistic Concepts For Application To Reliability, Maintainability And Supportability Data Analysis, Caroline Lubert Nov 1998

Introduction To Statistical And Probabilistic Concepts For Application To Reliability, Maintainability And Supportability Data Analysis, Caroline Lubert

Caroline P Lubert

No abstract provided.


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 …


Study On Electrosynthesis Of Butyl Butyrate At Conducting Oxide Anode Support On Titanium, Junxiang He, Jincheng Zhou Nov 1998

Study On Electrosynthesis Of Butyl Butyrate At Conducting Oxide Anode Support On Titanium, Junxiang He, Jincheng Zhou

Journal of Electrochemistry

Synthesis of butyl butyrate by direct electroxidation of n butyl alcohol and the electrochemical behaviors of several selected conducting oxide electrodes (Pb/PbO 2、Ti/PbO 2、i/SnO 2 +Sb 2O 3 /PbO 2 and Ti/SnO 2+Sb 2O 3+PdO x/PbO 2) have been investigated. The results demonstrated that the intermediate layers of SnO 2、Sb 2O 3 and PdO x could significantly decrease the interfacial resistance of the electrodes,and that the Ti/SnO 2+Sb 2O 3+PdO x/PbO 2 electrode possessed better electrocatelytic performance than others.


Double Differential Cross Section Of Helium Ionization By Proton Impact, A. L. Godunov, V. A. Schipakov, Michael Schulz Nov 1998

Double Differential Cross Section Of Helium Ionization By Proton Impact, A. L. Godunov, V. A. Schipakov, Michael Schulz

Physics Faculty Research & Creative Works

A theoretical analysis for doubly differential cross sections of the single ionization of helium by proton impact as a function of the scattering angle and projectile energy loss is presented. We have used two different theoretical methods. The first approach involved an approximate solution of Faddeev-Merkuriev equations for the three-body Coulomb problem. The second approach employed the expansion of the transition amplitude in the Born series over the projectile-target interaction up to second order. A relation between these two methods was established for the case of fast collisions. It has been demonstrated that, for small scattering angles, the post-collision interaction …


The Effect Of Suspended Particles On The Corrosion Resistance Of Electrodeposited Zinc Powders, Qingwen Li, Qing Yang, Xi Xia Nov 1998

The Effect Of Suspended Particles On The Corrosion Resistance Of Electrodeposited Zinc Powders, Qingwen Li, Qing Yang, Xi Xia

Journal of Electrochemistry

Zinc powders were electrodeposited from ZnCl 2 baths with containing suspension of unsoluble particles such as graphite, PbO 2,SnO 2,TiO 2, SiO 2 etc.. The structure, morphology and corrosion behavior of zinc powder were analyzed. SEM results showed that the dendritic growth of zinc can be inhibited by applying the suspension method. Suspension of PbO 2, SnO 2, TiO 2, SiO 2 and In 2O 3 could greatly improve the corrosion protection of zinc powder in 5 mol/L KOH. In addition, fractal theory is employed to further explain the results.


Electrochemical Investigation Of Effect Of Br - On Redox Behavior Of (Tpp)Co, Chuanwei Yan, Haichao Lin Nov 1998

Electrochemical Investigation Of Effect Of Br - On Redox Behavior Of (Tpp)Co, Chuanwei Yan, Haichao Lin

Journal of Electrochemistry

The effect of Br - anion on electrochemical behavior of (TPP)Co was investigated in 1,2 dichloroethane solution by microelectrode and thin layer cyclic voltammetry technique. It was found that the axially coordination of one Br - anion to (TPP)Co(Ⅲ)(Br -) 2 shifts the potential of porphyrin system to more positive value. The reduction peak of 0.12 V(vs.SCE) is attributed to the reduction of (TPP)Co(Ⅲ)(Br -). It is also postulated that the reduction of (TPP)Co(Ⅲ)(Br -) 2 occurred at a more negative potential where the reduction of the Co(Ⅱ)/Co(Ⅰ) process happened.


The Study On The Performance Of Mcfc Matrix Prepared By Flow Cast, Huaxin Lin, Baolian Yi, Naichao Li, Tianxi Qu, Enjun Zhang, Lianyin Kong, Yingcai Chen Nov 1998

The Study On The Performance Of Mcfc Matrix Prepared By Flow Cast, Huaxin Lin, Baolian Yi, Naichao Li, Tianxi Qu, Enjun Zhang, Lianyin Kong, Yingcai Chen

Journal of Electrochemistry

The matrix for MCFC were prepared by flow cast technique which gives reproducible and reliable results. Its mean pore radius is about 0.18 μm, and the porosity is about 65%. The performance of MCFC stacked with this type of matrix is 0.854 V at 200 mA/cm 2.


Primary Research Of Reversible Proton Exchange Membrane Regenerative Fuel Cells, Zhigang Shao, Baolian Yi, Ming Han Nov 1998

Primary Research Of Reversible Proton Exchange Membrane Regenerative Fuel Cells, Zhigang Shao, Baolian Yi, Ming Han

Journal of Electrochemistry

In this paper, we report the results of our studies on regenerative proton exchange membrane fuel cell(RPEMRFC) catalysts, electrode preparation and their performances. The Pt catalyst for the oxygen electrode was replaced by 60 w%Pt+40 w%IrO 2 which reduces polarization by 0.2 V in a polymer protone exchange membrane fuel cell. The cycle performance of RPEMRFC was found to be manly effected by the stability of the diffiusion layer of bifunctional oxygen electrode.


Corrosion Characteristics Of Electrodeposited Ni Mo P Alloy Immersed In Nacl Solution, Yue Zeng, Hongxin Huang, Xiaoming Xiao, Shixun Lian Nov 1998

Corrosion Characteristics Of Electrodeposited Ni Mo P Alloy Immersed In Nacl Solution, Yue Zeng, Hongxin Huang, Xiaoming Xiao, Shixun Lian

Journal of Electrochemistry

The corrosion characteristics of electrodeposited Ni Mo P alloy immersed in 5wt.% NaCl solution were investigated using immersion, anodic polarization curves, XPS and AES analysis. The corrosion rates of amorphous Ni Mo P alloys are lower than that of crystalline Ni Mo P alloys. Anodic polarization curve experiments show that for the electrodeposited Ni Mo P alloys, the nickel mol fraction of which has in between 0.719 and 0.868, the corrosion potential moves to positive with the increase of P content, and the peak current value of active region increase with the increase of Mo content in alloys, though the …


Study Of The Effect Of Rare Earth Ions On Dna Using Cyclic Voltammetry And Spectroscopy, Heibai Shen, Yuzhuan Kang, Haifeng Yang, Lin Yu, Zongrang Zhang Nov 1998

Study Of The Effect Of Rare Earth Ions On Dna Using Cyclic Voltammetry And Spectroscopy, Heibai Shen, Yuzhuan Kang, Haifeng Yang, Lin Yu, Zongrang Zhang

Journal of Electrochemistry

The interaction between rare earth ions(e.g.Eu 3+ ,Ce 3+ ,Er 3+ ,Sm 3+ ,Tb 3+ ,La 3+ and Nd 3+ ) and DNA had been investigated by using Cyclic Voltammetry, Ultraviolet and Raman Spectroscopy. After the adding of Ce 3+ ion to DNA solution, the cathodic peak current of Ce 3+ ion reduction was found to decrease obviously, and the anodic peak current to decrease even more significantly. Differential UV spectra of Ce 3+ ion depicted hyperchromic effect after the reaction of these two species and a new peak of 272 nm was found. Differential UV spectra of DNA also …