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1998

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Articles 61 - 90 of 2574

Full-Text Articles in Physical Sciences and Mathematics

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 …


Management Of The Houtman Abrolhos System., Kim Nardi, Abrolhos Islands Management Advisory Committee Dec 1998

Management Of The Houtman Abrolhos System., Kim Nardi, Abrolhos Islands Management Advisory Committee

Fisheries management papers

The Abrolhos System is the Houtman Abrolhos Islands and adjoing State Territorial Waters. It is an important part of the Western Australian environment. Has major significance in conservation of flora and fauna and also in geological terms. The waters adjoining State Territorial Waters contain some of the most highly valued marine systems in the State. These include sites of historical shipwrecks in Australia. The are of great interest to visitors and support a relatively small but growing recreation and tourism industy.

The area is integral to the Western rock lobster fishery, which is that State's premier primary industries. The Abrolhos …


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. …


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 …


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 …


Analysis Of Doubly Excited State Resonances Below The Li(5p) Threshold In Li- Photodetachment, Chien-Nan Liu, Anthony F. Starace Dec 1998

Analysis Of Doubly Excited State Resonances Below The Li(5p) Threshold In Li- Photodetachment, Chien-Nan Liu, Anthony F. Starace

Anthony F. Starace Publications

Larger scale eigenchannel R-matrix calculations than those of Pan et al.  [Phys. Rev. A53, 840 (1996)] confirm the prediction of a 2-meV-wide resonance feature at a photon energy of 5.421 eV in the Li (3s) partial cross section resulting from photodetachment of Li-. This resonance was neither clearly observed nor identified in measurements of Ljungblad et al. [Phys. Rev. Lett. 77, 3751 (1996)]. We identify this resonance as a N{υ}nA=5{1}6- state [having angular symmetry (K,T)A=(2,0) - or (n …


Closed-Loop Object Recognition Using Reinforcement Learning, Jing Peng, Bir Bhanu Dec 1998

Closed-Loop Object Recognition Using Reinforcement Learning, Jing Peng, Bir Bhanu

Department of Computer Science Faculty Scholarship and Creative Works

Current computer vision systems whose basic methodology is open-loop or fi'/tertype typically use image segmentation followed by object recognition algorithms. These systems are not robust for most real-world applications. In contrast the system presented here achieves robust performance by using reinforcement learning to induce a mapping from input images to corresponding segmentation parameters. This is accomplished by using the confidence level of model matching as a reinforcement signal for a team of learning automata to search for segmentation parameters during training. The use of the recognition algorithm as part of the evaluation function for image segmentation gives rise to significant …


Optimizing Amplifier Placements In A Multiwavelength Optical Lan/Man: The Unequally Powered Wavelengths Case, Byrav Ramamurthy, Jason Iness, Biswanath Mukherjee Dec 1998

Optimizing Amplifier Placements In A Multiwavelength Optical Lan/Man: The Unequally Powered Wavelengths Case, Byrav Ramamurthy, Jason Iness, Biswanath Mukherjee

School of Computing: Faculty Publications

Optical networks based on passive-star couplers and employing WDM have been proposed for deployment in local and metropolitan areas. These networks suffer from splitting, coupling, and attenuation losses. Since there is an upper bound on transmitter power and a lower bound on receiver sensitivity, optical amplifiers are usually required to compensate for the power losses mentioned above. Due to the high cost of amplifiers, it is desirable to minimize their total number in the network. However, an optical amplifier has constraints on the maximum gain and the maximum output power it can supply; thus, optical amplifier placement becomes a challenging …


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 …


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 …


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 …


Tuple Source Relational Model: A Source-Aware Data Model For Multidatabases, Ee Peng Lim, Roger Hsiang-Li Chiang, Yinyan Cao Dec 1998

Tuple Source Relational Model: A Source-Aware Data Model For Multidatabases, Ee Peng Lim, Roger Hsiang-Li Chiang, Yinyan Cao

Research Collection School Of Computing and Information Systems

In some integration projects, complete integration of database instances may not be necessary. It may also be too costly and impossible to do so due to poor local data quality and insufficient instance-level knowledge. In this research, we study how multidatabases with global schemas should be represented and manipulated when the data instances from the local databases do not require to be fully integrated. We propose the tuple source (TS) relational model to represent multidatabases under such an integration requirement. This model extends the classical relational model by augmenting every relation with a source attribute to identify the local database …


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.


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 …


The Motions Of Clusters Of Galaxies And The Dipoles Of The Peculiar Velocity Field, Riccardo Giovanelli, Martha P. Haynes, John J. Salzer, Gary Wegner Dec 1998

The Motions Of Clusters Of Galaxies And The Dipoles Of The Peculiar Velocity Field, Riccardo Giovanelli, Martha P. Haynes, John J. Salzer, Gary Wegner

Dartmouth Scholarship

In preceding papers of this series, TF relations for galaxies in 24 clusters with radial velocities between 1000 and 9200 km s-1 (SCI sample) were obtained, a Tully-Fisher (TF) template relation was constructed, and mean offsets of each cluster with respect to the template were obtained. Here, an estimate of the line-of-sight peculiar velocities of the clusters and their associated errors are given. It is found that cluster peculiar velocities in the cosmic microwave background reference frame do not exceed 600 km s-1 and that their distribution has a line-of-sight dispersion of 300 km s-1, suggesting …


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 …


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.


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 …


Study On Ni Co S Mo Alloys New Cathode Material For Aquous Electrolysis, Yuanshou Xie, Quanfeng Liu Nov 1998

Study On Ni Co S Mo Alloys New Cathode Material For Aquous Electrolysis, Yuanshou Xie, Quanfeng Liu

Journal of Electrochemistry

The parameters of electrodeposion of Ni Co S Mo alloy were studied. The experimental results indicate that the electrodeposition alloy shows high catalytic activity for hydrogen evolution reaction, as well as better mechanical strength and higher chemical stability. The mechanism of catalytic hydrogen evolution reaction on this type of alloy electrode was also investigated by means of polarization curve and cyclic voltametry.


The Latest World Wide Progress In Solid Oxide Fuel Cell, Jiang Yi Nov 1998

The Latest World Wide Progress In Solid Oxide Fuel Cell, Jiang Yi

Journal of Electrochemistry

Solid oxide fuel cell(SOFC) is a novel, green electricity generation technology, which has been showing rapid development since 1980's. In light of its high efficiency, environmental friendly, fuel adaptability and long term stability, the Research, Development and Demonstration(RD&D) of this hype of full cell have been emphasized in a large number of developed countries. Based on the information communicated at the latest symposium on SOFC held last year in Aachen(Germany) and the knowledge gained through years of research in this field, a comprehensive review on the latest development of the tubular, this planar SOFC as well as on a number …


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 …


Drect Electro_Oxidation Synthesis Of D Arabinose On Spectroscopic Graphite Electrode, Hei Wei, Huang Ying Nov 1998

Drect Electro_Oxidation Synthesis Of D Arabinose On Spectroscopic Graphite Electrode, Hei Wei, Huang Ying

Journal of Electrochemistry

D Arabinose synthesized by direct electro_oxidative decarboxylation of D gluconate on graphite electrode from aqueous solutions. The effects of D gluconate concentration, electrolysis potential, temperature and electrolyte composition on the current efficiency and product yield of electrosynthsis are discussed. The laboratory scale electrosynthesis was achieved with flow through cell.The optimum technology conditions for electrosynthesis were obtained with orthogonal design method.Both galvanostatic and potentionstatic conditions have been exploited, the later was found to be more effective.


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.


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.


A Preliminary Study Of The Synthesis Of Tin Based Amorphous Material And Its Behavior On Lithium Intercalation, Li Liu, Hanxi Yang, Jutang Sun, Xingping Ai Nov 1998

A Preliminary Study Of The Synthesis Of Tin Based Amorphous Material And Its Behavior On Lithium Intercalation, Li Liu, Hanxi Yang, Jutang Sun, Xingping Ai

Journal of Electrochemistry

An amorphous lithium inserting anode material based on Tin oxide glass was synthesized by salification in solution and its properties on lithium intercalation was investigated by X ray diffraction(XRD), microelectrode voltammetry and charge discharge measurements. The results have shown that this kind of material has considerable electrochemical reversibility toward lithium intercalation deintercalation. The available discharge capacity of the material reaches 430 mA·h/g with charge_discharge efficiency over 90%, showing a great potential for practical use.


The Study Of Poly [N (3 Ferrocene Acetamino Propyl Pyrrole] Film Modified Glucose Electrode, Chengyun Tian, Jing Chen, Li Zhang Nov 1998

The Study Of Poly [N (3 Ferrocene Acetamino Propyl Pyrrole] Film Modified Glucose Electrode, Chengyun Tian, Jing Chen, Li Zhang

Journal of Electrochemistry

A poly [N (3 ferrocene acetamino propyl pyrrole)]film modified electrode was fabricated and studied by cyclic voltammetric method. The result shows that the modified electrode can give stable redox peaks of ferrocene, and an obvious catalytic peak due to glucose; This modified electrode was used to tabricate a glucose sensor which operates at +0.2 V, so that the ascorbic acid or uric acid doesn't affect the accuracy detection of glucose concentration. The sensor has a linear range of 0.1~10 mmol/L glucose, which the period of long term stability and response time of the sensor are about ten days and 2 …