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Articles 172291 - 172320 of 198066

Full-Text Articles in Engineering

The Role Of Oxygen At The Second Discharge Plateau Of Nickel Hydroxide, Sathya Motupally, Mukul Jain, Venkat Srinivasan, John W. Weidner Jan 1998

The Role Of Oxygen At The Second Discharge Plateau Of Nickel Hydroxide, Sathya Motupally, Mukul Jain, Venkat Srinivasan, John W. Weidner

Faculty Publications

It was shown that the appearance of a secondary discharge plateau approximately 400 mV below the primary plateau can result from the reduction of oxygen. During the galvanostatic discharge of planar nickel-hydroxide films at room temperature and in 3 weight percent KOH solutions, the second discharge plateau was observed only in the presence of dissolved oxygen in the electrolyte. When the solution was deoxygenated, no residual capacity could be extracted from the films even at low discharge rates or from overcharged films. In addition, the duration of the second plateau is inversely proportional to the square of the discharge current, …


Steady-State Modeling Of A Parallel-Plate Electrochemical Fluorination Reactor, Kamal Jha, Gerald L. Bauer, John W. Weidner Jan 1998

Steady-State Modeling Of A Parallel-Plate Electrochemical Fluorination Reactor, Kamal Jha, Gerald L. Bauer, John W. Weidner

Faculty Publications

A steady-state mathematical model of a parallel-plate reactor was developed for studying the electrochemical fluorination of organic compounds dissolved in anhydrous hydrogen fluoride. The model incorporates two-phase flow with differential material, energy, and pressure balances. Profiles of temperature, pressure, vapor volume fraction, and current density in the reactor are presented at two inlet temperatures to provide insight into the operation of the reactor. The effects of the inlet temperature, feed flow rate, and cell current on the cell pack voltage and current efficiency of the reactor are presented to determine problematic operating regions for the reactor. Optimum operating currents based …


Measurement Of Thin Liquid Film Drainage Using A Novel High-Speed Impedance Analyzer, Kevin O. Hool, Robert C. Saunders, Harry J. Ploehn Jan 1998

Measurement Of Thin Liquid Film Drainage Using A Novel High-Speed Impedance Analyzer, Kevin O. Hool, Robert C. Saunders, Harry J. Ploehn

Faculty Publications

This work describes the design and implementation of a new instrument, called the thin film impedance analyzer, which measures the rate of drainage of thin oil films. The instrument forms an oil film by elevating a planar oil–water interface into a water drop hanging from a stainless steel capillary tube immersed in the oil. The instrument measures the magnitude of the impedance of the matter between the capillary tube and a screen electrode immersed in the lower water phase. Under appropriate conditions, the capacitance of the oil film dominates the impedance. The instrument records the increase in the magnitude of …


Agent Jurisprudence, Michael N. Huhns, Munindar P. Singh Jan 1998

Agent Jurisprudence, Michael N. Huhns, Munindar P. Singh

Faculty Publications

The agent metaphor comes packaged with a number of powerful abstractions. Some of these are psychological, such as beliefs, knowledge, and intentions-abstractions that were traditionally studied in AI. However, there are a number of other abstractions that the agent metaphor brings to the fore. Of these, one has been emphasizing the social abstractions. Close cousins of the social abstractions are the ethical and legal abstractions. These too are being recognized as increasingly important in developing agents that are not only sociable, but also well behaved.


Opto-Electronic Sensor System For Rapid Evaluation Of Planter Seed Spacing Uniformity, Michael F. Kocher, Yubin Lan, Changhe Chen, John A. Smith Jan 1998

Opto-Electronic Sensor System For Rapid Evaluation Of Planter Seed Spacing Uniformity, Michael F. Kocher, Yubin Lan, Changhe Chen, John A. Smith

Department of Agricultural and Biological Systems Engineering: Faculty Publications

An opto-electronic seed spacing evaluation system that measured time intervals between seeds and detected front-to-back location of seed drop events relative to the planter was used to rapidly determine planter seed spacing uniformity in the laboratory. The seed detection sensor for the opto-electronic system consisted of a rectangular photogate with 24 phototransistors receiving light beams from 24 LEDs opposite to them. The system also included circuitry to interface the photogate with a digital I/O board in a personal computer. The opto-electronic system was tested with three planter configurations. During the tests, the photogate was positioned beneath the seed drop tube …


Optical Digital Fragmentation Measuring Systems -- Inherent Sources Of Error, Norbert H. Maerz, Wei Zhou Jan 1998

Optical Digital Fragmentation Measuring Systems -- Inherent Sources Of Error, Norbert H. Maerz, Wei Zhou

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Automated optical imaging systems of measuring fragmentation are increasingly being used in the mining, comminution, and materials handling industries. These methods have been well received in many of the industries involved. Considering that in many of these applications there are no alternative ways of sizing material, having even a rudimentary measurement of size distributions allows evaluations of explosive, blast design, detonator performance, crusher and milling performance, and material degradation due to transport.

Optical methods have inherent limitations, which reflect on accuracy, precision, and reproducibility of measurement results. This stems from the fact that there are myriads of variables, which affect …


Methods For Predicting Shale Durability In The Field, Paul Michael Santi, Jerry D. Higgins Jan 1998

Methods For Predicting Shale Durability In The Field, Paul Michael Santi, Jerry D. Higgins

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Durability of shales and other weak rock is an important parameter describing the material's susceptibility to breakdown upon exposure to water or during construction work. While laboratory methods have been developed to measure durability, no correlations between laboratory results and simple field tests have been determined. The results of this study show that certain field parameters can predict slake durability with acceptable accuracy. The recommended field tests, in order of desirability, are slake index, jar slake, hammer rebound, and NGI "Q" value. Single variable and multiple variable linear regression equations are given, including equations conservatively modified so that 95% of …


Evaluation Of Toxicity, Bioavailability And Speciation Of Lead, Zinc And Cadmium In Mine/Mill Wastewaters, Mujde Erten-Unal, Bobby G. Wixson, Nord Gale, Jerry L. Pitt Jan 1998

Evaluation Of Toxicity, Bioavailability And Speciation Of Lead, Zinc And Cadmium In Mine/Mill Wastewaters, Mujde Erten-Unal, Bobby G. Wixson, Nord Gale, Jerry L. Pitt

Civil & Environmental Engineering Faculty Publications

The toxicity of common compounds of lead, cadmium and zinc was evaluated in waters similar to that found in the world's largest lead producing area in Missouri. Static, acute toxicity tests were performed using fathead minnows (Pimephales promelas) and water fleas (Daphnia magna) respectively. Test organisms were subjected to varying amounts of sulfide, carbonate, chloride and sulfate salts of lead, zinc and cadmium mixed in hard, alkaline waters typical to this region. Median lethal concentrations were calculated using nominal versus measured metal concentrations. Measured metal concentrations included four different metal fractionation (extraction/filtration) techniques at different pH …


Temperature Dependence Of Step Density On Vicinal Pb(111), Z. H. Zhang, H. E. Elsayed-Ali Jan 1998

Temperature Dependence Of Step Density On Vicinal Pb(111), Z. H. Zhang, H. E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

The temperature dependence of step density on the vicinal Pb(111) surface is investigated using reflection high-energy electron diffraction. When the temperature is increased from 323 to 590 K. the average terrace width and the average string length at the step edge decrease from 85±25 to 37±16 Å and from 220±33 to 25±8 Å, respectively. Thermal step collapse on the Pb(111) surface near its bulk melting temperature is not observed. Above 530±7 K, the change in the string length at the step edge with temperature becomes small, and the intensity of the (00) beam is significantly decreased. We conclude that partial …


Atomic Hydrogen Cleaning Of Inp(100) For Preparation Of A Negative Electron Affinity Photocathode, K. A. Elamrawi, M. A. Hafez, H. E. Elsayed-Ali Jan 1998

Atomic Hydrogen Cleaning Of Inp(100) For Preparation Of A Negative Electron Affinity Photocathode, K. A. Elamrawi, M. A. Hafez, H. E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Atomic hydrogen cleaning is used to clean InP(100) negative electron affinity photocathodes. Reflection high-energy electron diffraction patterns of reconstructed, phosphorus-stabilized, InP(100) surfaces are obtained after cleaning at ∼400 °C. These surfaces produce high quantum efficiency photocathodes (∼8.5%), in response to 632.8 nm light. Without atomic hydrogen cleaning, activation of InP to negative electron affinity requires heating to ∼530 °C. At this high temperature, phosphorus evaporates preferentially and a rough surface is obtained. These surfaces produce low quantum efficiency photocathodes (∼0.1%). The use of reflection high-energy electron diffraction to measure the thickness of the deposited cesium layer during activation by correlating …


Modeling Electromagnetic Disturbances In Closed-Loop Computer Controlled Flight Systems, W. Steven Gray, Oscar R. Gonzalez Jan 1998

Modeling Electromagnetic Disturbances In Closed-Loop Computer Controlled Flight Systems, W. Steven Gray, Oscar R. Gonzalez

Electrical & Computer Engineering Faculty Publications

High intensity electromagnetic radiation has been demonstrated to be a source of computer upsets in commercially available digital flight control systems. In this paper we introduce an electromagnetic disturbance model which can be used for stability analysis and augmentation of any such digitally implemented control law. The model is composed of a Markovian exosystem supplying radiation events to a discrete-time jump linear system which models how the radiation interferes with the nominal operation of the closed-loop system. We discuss how this model can be used to characterize stability and how it can be parametrized and validated in an experimental setting.


Measuring Fine Aggregate Shape By Digital Imaging, Larry David Klotz Jan 1998

Measuring Fine Aggregate Shape By Digital Imaging, Larry David Klotz

Theses and Dissertations

Fine aggregate shape has been identified as a factor in determining asphalt pavement rutting susceptibility. In an effort to improve test methods for measuring aggregate shape characteristics, a video-based, computer-controlled imaging system was developed. Individual aggregate particles were characterized by shape attributes. A neural network classifier used these attributes to calculate a single number classification index that relates to expected performance in asphalt concrete based on angularity. Expert judges were used to train the neural network classifier by scoring a set of particle outlines. Discrepancies in the expert's scores indicate that considerable uncertainties still exist in the concept of 'angularity'. …


Disaggregation Procedures For Stochastic Hydrology Based On Nonparametric Density Estimation, David G. Tarboton, Ashish Sharma, Upmanu L. Lall Jan 1998

Disaggregation Procedures For Stochastic Hydrology Based On Nonparametric Density Estimation, David G. Tarboton, Ashish Sharma, Upmanu L. Lall

Civil and Environmental Engineering Faculty Publications

Synthetic simulation of streamflow sequences is important for the analysis of water supply reliability. Disaggregation models are an important component of the stochastic streamflow generation methodology. They provide the ability to simulate multiseason and multisite streamflow sequences that preserve statistical properties at multiple timescales or space scales. In recent papers we have suggested the use of nonparametric methods for streamflow simulation. These methods provide the capability to model time series dependence without a priori assumptions as to the probability distribution of streamflow. They remain faithful to the data and can approximate linear or nonlinear dependence. In this paper we extend …


Controlled Environment Potentiostat To Study Solid-Aqueous Systems, R A. Petrie, P. R. Grossl, Ronald C. Sims Jan 1998

Controlled Environment Potentiostat To Study Solid-Aqueous Systems, R A. Petrie, P. R. Grossl, Ronald C. Sims

Biological Engineering Faculty Publications

We designed a redox apparatus that controls electropotenial (Eh), pH, and temperature. The apparatus is fully automated and can be assembled from equipment found in most soil analytical laboratories. The reactor can maintain environmental conditions used to evaluate the chemical fate of contaminants under natural conditions (natural attenuation) or adjust them to a new steady state to evaluate the effect of engineered remediation on a subsurface system. It can operate within a wide range of redox potential values (−400 to 400 mV) and at any pH value. The stability and accuracy of the instrument was tested by performing Eh-pH titrations …


Adaptive Shape From Shading, Ati̇lla Gülteki̇n, Muhi̇tti̇n Gökmen Jan 1998

Adaptive Shape From Shading, Ati̇lla Gülteki̇n, Muhi̇tti̇n Gökmen

Turkish Journal of Electrical Engineering and Computer Sciences

Extracting surface orientation and surface depth from one or more images is one of the classic problems in computer vision. Shape-from-shading (SFS) deals with the recovery of 3-D shape from a single shaded image. The shape is recovered by minimizing an energy functional involving constraints such as smoothness. In this constrained problem, although the smoothness constraint helps to stabilize the minimization process, it pushes the reconstruction toward a smooth surface. In this paper, we present a new adaptive shape-from-shading method which reduces this oversmoothing by controlling the smoothness spatially over the image space. In order to improve the quality of …


A Parallel Pipelined Computer Architecture For Digital Signal Processing, Haluk Gümüşkaya, Bülent Örenci̇k Jan 1998

A Parallel Pipelined Computer Architecture For Digital Signal Processing, Haluk Gümüşkaya, Bülent Örenci̇k

Turkish Journal of Electrical Engineering and Computer Sciences

This paper presents a parallel pipelined computer architecture and its six network configurations targeted for the implementation of a wide range of digital signal processing (DSP) algorithms described by both atomic and large grain data flow graphs. The proposed architecture is considered together with programmability, yielding a system solution that combines extensive concurrency with simple programming. It is an SSIMD (Skewed Single Instruction Multiple Data) or MIMD (Multiple Instruction Multiple Data) machine depending on the algorithms implemented and the programming methodologies. The concurrency that can be exploited by the algorithms using this Parallel pipelined architecture is both temporal and spatial …


Hierarchical Interconnection Network Architecture For Real-Time Systems, Bülent Örenci̇k Jan 1998

Hierarchical Interconnection Network Architecture For Real-Time Systems, Bülent Örenci̇k

Turkish Journal of Electrical Engineering and Computer Sciences

A hierarchical network suitable for interconnection of real-time client processes in a distributed multiprocessor environment is presented in this paper. A multi-layer {\it Communication Unit} (CU) prototype is developed for this purpose. This unit offers the client processes communication services for real-time operation. These services are structured in such a way that they do not depend on the characteristics of the communication medium. The basic hardware of the CU consists of a PC compatible card connected to the VME Bus. Client processes run on target cards (Motorola MVME-162) which are attached to the same bus. Target cards together with a …


Imaging Tissue Conductivity Via Contactless Measurements: A Feasibility Study, Nevzat G. Gençer, M. Nejat Tek Jan 1998

Imaging Tissue Conductivity Via Contactless Measurements: A Feasibility Study, Nevzat G. Gençer, M. Nejat Tek

Turkish Journal of Electrical Engineering and Computer Sciences

The feasibility of a new imaging system is investigated. This system will be used to image electrical conductivity distribution of biological tissues via contactless measurements. This will be achieved by introducing currents in the conductive medium using time-varying magnetic fields and measuring the magnetic fields of the induced currents. Consequently, the imaging system consists of transmitter and receiver coils placed nearby the conductive body. In this study, the basic features of the coplanar and coaxial coils are studied. The validity of the simplifying assumptions for the governing field equations is investigated. It is found that, for operating frequency of 100 …


Hazardous Waste Determination And Government Enforcement Actions In The Resource Conservation And Recovery Act And The Law No. 24051: Comparison Between The United States And Argentina, Eduardo Jose Conghos Jan 1998

Hazardous Waste Determination And Government Enforcement Actions In The Resource Conservation And Recovery Act And The Law No. 24051: Comparison Between The United States And Argentina, Eduardo Jose Conghos

LLM Theses and Essays

The incremental generation and disposal of hazardous waste, causing severe environmental pollution, has become one the world’s most important ecological problems starting with the Stockholm Conference in 1972. This paper examines two legislative reactions to pollution caused by hazardous wastes in the United States, under the Resource Conservation and Recovery Act 1976 (RCRA), and Argentina, in Law No. 24051. This paper makes a comparative analysis of the material provisions of both the RCRA and the Law with emphasis on the tools and actions provided for the enforcement of the RCRA and the Law. The paper concludes that the RCRA and …


A New Regulatory Environment For The Telecommunication Industry, Jerome Lavigne Delville Jan 1998

A New Regulatory Environment For The Telecommunication Industry, Jerome Lavigne Delville

LLM Theses and Essays

The idea of information superhighways has been spurred by consumer demand, technological development and political institutions. These advancements and interests require a regulatory framework to control the operation of, and competition within the telecommunications industry. This paper focuses on government regulation of telecommunication carriers, information services (internet), video-programming and wireless telecommunication (spectrum). This paper also highlights the roles of the Federal Communication Commission (FCC) under the Telecommunications Act of 1996 as compared to previous laws prior to the 1996 Act.


Copyright Protection Of Software, Severine Desimpelaere Jan 1998

Copyright Protection Of Software, Severine Desimpelaere

LLM Theses and Essays

Computer technology has developed within the last decades with many advancements which require intellectual property protections. This thesis addresses the need for the legal protection of software by the vast body of copyright laws. This thesis examines the history, nature, textual and practical compositions of copyright laws and their adaptability to computer technology. The thesis further analyses the scope of copyright protection with emphasis on the Computer Software Copyright Act of 1980 (CSCA), the regime of international conventions for the protection of software as well as other statutory protections for the owners and users of the software. The thesis concludes …


Study Of Electronic Cash: Its Impact On The Economy And Society, And Its Future, Sanjana Prasad Jan 1998

Study Of Electronic Cash: Its Impact On The Economy And Society, And Its Future, Sanjana Prasad

LLM Theses and Essays

Technological advancement has introduced an electronic method for the payment for goods and services. With these advancements and the growth of the internet, the market-place of the world has become one universe without borders. This paper examines the various methods of electronic payment for goods and services and the domestic and international laws that govern their operations. The paper explores concerns about money laundering, counterfeiting, internet security, cyber scams in electronic cash as well as proffered security solutions to these problems. The paper concludes with the proposition that electronic cash in the form of cards (ATM) are more accessible to …


Automatic Car Registration Plate Recognition Using The Hough Transform, Shokri Gendy Jan 1998

Automatic Car Registration Plate Recognition Using The Hough Transform, Shokri Gendy

Theses: Doctorates and Masters

The development of automatic car registration plate recognition systems will provide greater efficiency for vehicle monitoring in automatic access control, and will avoid the need to equip vehicles with special RF tags for identification since all vehicles possess a unique registration plate. Thus this study is an attempt to introduce an automatic car registration plate recognition system based on identifying the plate characters by using the Hough transform. However, the proposed recognition system can be used in conjunction with a tag system for higher security access control. The automatic registration plate recognition could also have considerable potential in a wide …


Remax: Software For Optimizing Ground-Water Management, Conjunctive Water Management, And Remediation Design, Richard C. Peralta, Alaa H. Aly Jan 1998

Remax: Software For Optimizing Ground-Water Management, Conjunctive Water Management, And Remediation Design, Richard C. Peralta, Alaa H. Aly

Civil and Environmental Engineering Faculty Publications

REMAX is a software package designed to assist water managers in developing optimal ground water or coordinated ground water/surface water strategies for a wide range of management problems. REMAX uses MODFLOW, MT3D, and other simulation models to develop the response matrix or response surface equations employed in the final optimization model. To address nonlinear systems (e.g., unconfined aquifers) accurately, REMAX uses a modified response-matrix method. REMAX several nonlinear functions to represent a wide variety of nonlinear response surfaces. REMAX can be used for deterministic or reliability-based optimization problems. Decision variables are ground-water extraction/injection rates and/or surface water diversion rates. State …


Proposed Model Rules Governing The Admissibility Of Computer-Generated Evidence, Lynn Mclain, James E. Carbine Jan 1998

Proposed Model Rules Governing The Admissibility Of Computer-Generated Evidence, Lynn Mclain, James E. Carbine

All Faculty Scholarship

Pursuant to a grant from the State Justice Institute, the Court of Appeals of Maryland Standing Committee on Rules of Practice and Procedure drafted, and the Court of Appeals adopted, model rules regarding computer-generated animations and simulations. The rules address discovery, pretrial rulings, and preservation of the record for appeal.


Microwave Filtering Of Unwanted Oscillations On Base Of Hexagonal Ferrite Composite Thick Films, Marina Koledintseva, Alexander A. Kitaytsev, Andrey A. Shinkov Jan 1998

Microwave Filtering Of Unwanted Oscillations On Base Of Hexagonal Ferrite Composite Thick Films, Marina Koledintseva, Alexander A. Kitaytsev, Andrey A. Shinkov

Electrical and Computer Engineering Faculty Research & Creative Works

The paper is aimed at the design of waveguide filters of lower frequencies using composite thick films (CTF) made of high-anisotropy polycrystalline hexagonal ferrite powders. Theoretical and experimental results describing the possibility of forming the desired frequency characteristic of the filters are presented


Making Concrete Less Abstract, David Newton Richardson Jan 1998

Making Concrete Less Abstract, David Newton Richardson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

CE 3 13 is a second level properties of concrete lecture course. In an effort to make it appear less abstract to the students, over the course of several semesters several learning strategies were tried, including journaling, muddiest point, entering the academy, role playing, bookends-on-a-lecture, and hands-on lab projects. Most recently, an emphasis on short writing-to-learn papers, a problems-based stance, and an integrated lab project was used. Student evaluations indicated that the lab projects and the increased writing was of significant benefit in promotion of learning.


University Of Texas At Tyler Freshman Catalog, 1998-1999, University Of Texas At Tyler Jan 1998

University Of Texas At Tyler Freshman Catalog, 1998-1999, University Of Texas At Tyler

Catalogs

Archives Space instance: https://archivesspace.uttyler.edu/repositories/2/archival_objects/22363


Evaluation Of Implicit Numerical Methods For Building Energy Simulation, Michael Crowley, Saleem Hashmi Jan 1998

Evaluation Of Implicit Numerical Methods For Building Energy Simulation, Michael Crowley, Saleem Hashmi

Articles

The stability of numerical methods used for finite-difference thermal modelling of buildings is discussed. A known instability in a commonly used process is described and alternative numerical methods with suitable stability properties are identified. With a view to selecting the optimum numerical method, the building energy simulation problem is characterized mathematically and appropriate implicit solvers are compared on the basis of accuracy and computational effort using a building related test problem prepared for this purpose. A recently developed numerical method with the necessary strong stability is found to possess higher computational efficiency than methods frequently used in this application and …


A Methodology For The Analysis Of Its Impacts On Mobility, Air Quality, And Land Use, Kumares C. Sinha, Srinivas Peeta, Muhammed Amer Sultan, Kamalakar Poonuru, Nadine-Jenelle K. Richards Jan 1998

A Methodology For The Analysis Of Its Impacts On Mobility, Air Quality, And Land Use, Kumares C. Sinha, Srinivas Peeta, Muhammed Amer Sultan, Kamalakar Poonuru, Nadine-Jenelle K. Richards

JTRP Technical Reports

The Indiana Department of Transportation (INDOT) is currently implementing (or has implemented) several components of Intelligent Transportation Systems (ITS). This includes a mini Advanced Traffic Management Systems (ATMS) implemented on a three-mile stretch of the Borman Expressway to evaluate advanced non-intrusive sensor systems and the associated communication infrastructure for the installation of a full-scale ATMS on the 16-mile stretch of the Borman Expressway. Potential specific ITS technologies that are either being implemented or are being considered include pre-trip information, en-route information, variable message signs, and Hoosier Helpers. It is expected that the implementation of various ITS technologies on the Borman …