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Articles 174391 - 174420 of 198023

Full-Text Articles in Engineering

Building Distributed Applications With Design Patterns, Gruia-Catalin Roman, James C. Hu Jan 1996

Building Distributed Applications With Design Patterns, Gruia-Catalin Roman, James C. Hu

All Computer Science and Engineering Research

Design patterns are a topic of great current interest within the object-oriented programming community. The motivation is both economical and intellectual. On one hand, there is the hope of establishing a common culture and language that fosters communicatino and growth in the software engineering field. While a community dominated by empiricism is seeking to achieve higher levels of formality by capturing its experiences in the form of catalogs of design patterns, another community, deeply rooted in formal thinking, is seeking to make its mark on the every day workings of the software engineering process. Distributed algorithms and the heuristics used …


Microhollow Cathode Discharges, K. H. Schoenbach, R. Verhappen, R. Tessnow, F. E. Peterkin, W. W. Byszewski Jan 1996

Microhollow Cathode Discharges, K. H. Schoenbach, R. Verhappen, R. Tessnow, F. E. Peterkin, W. W. Byszewski

Bioelectrics Publications

The current–voltage characteristics of hollow cathode discharges and their predischarges in argon under dc and pulsed conditions were found to have a positive slope at pressures up to approximately 50 Torr, and currents up to 20 mA, at a hole diameter of 0.7 mm. In this range of pressure and current, parallel operation of hollow cathode discharges, without ballast, was demonstrated. Scaling to higher pressure is possible by reducing the hole diameter. Pulsed experiments with an array of cathode rings of 75 μm diameter allowed us to obtain parallel operation of more than 50 discharges at a pressure of 350 …


Investigation Of Electrotribological And Arc Erosion Behavior Of Cu-15vol.%Cr In Situ Composite, Zhongyu Chen Jan 1996

Investigation Of Electrotribological And Arc Erosion Behavior Of Cu-15vol.%Cr In Situ Composite, Zhongyu Chen

Masters Theses

Electrotribological and arc erosion behavior of Cu-15vol.%Cr in situ composite was investigated in terms of coefficient of friction, interfacial resistance, bulk temperature, and wear rate as a function of normal pressure, sliding speed, and electrical current. Microstructural change due to electrical sliding was studied to understand wear mechanisms. Cu-15vol.%Cr in situ composite was selected in this research because it exhibits an excellent combination of mechanical strength and electrical/thermal conductivity.

It was found that the average coefficient of friction decreased with increasing electrical current under dry electrical sliding. The average coefficient of friction was lower under lubricated electrical sliding than that …


A Self-Consistent Numerical Method For Simulation Of Quantum Transport In High Electron Mobility Transistor; Part 1: The Boltzmann-Poisson-Schrodinger Solver, Rahim Khoie Jan 1996

A Self-Consistent Numerical Method For Simulation Of Quantum Transport In High Electron Mobility Transistor; Part 1: The Boltzmann-Poisson-Schrodinger Solver, Rahim Khoie

Electrical & Computer Engineering Faculty Research

A self-consistent Boltzmann-Poisson-Schrödinger solver for High Electron Mobility Transistor is presented. The quantization of electrons in the quantum well normal to the heterojunction is taken into account by solving the two higher moments of Boltzmann equation along with the Schrödinger and Poisson equations, self-consistently. The Boltzmann transport equation in the form of a current continuity equation and an energy balance equation are solved to obtain the transient and steady-state transport behavior. The numerical instability problems associated with the simulator are presented, and the criteria for smooth convergence of the solutions are discussed. The current-voltage characteristics, transconductance, gate capacitance, and unity-gain …


Testreview 1.0: User’S Manual, John Chituanya Okoli Jan 1996

Testreview 1.0: User’S Manual, John Chituanya Okoli

Honors Capstones

No abstract provided.


Investigation Of Wetting Hydrodynamics Using Numerical Simulations, David E. Finlow, Prakash R. Kota, Arijit Bose Jan 1996

Investigation Of Wetting Hydrodynamics Using Numerical Simulations, David E. Finlow, Prakash R. Kota, Arijit Bose

Chemical, Biomolecular, and Materials Engineering Faculty Publications

Meniscus shapes from a simulation of a plate immersing into an infinitely deep liquid bath, for a range of outer length scales, have been obtained numerically. These have been compared with the leading‐order prediction from a three‐region asymptotic analysis done in the double limit, Capillary number, Ca→0, LS/LC→0, with Ca ln(LC/LS) of O(1), where LS and LC represent the slip length and an outer macroscopic length, respectively. For Ca<0.01, the numerically computed and the perturbation solutions show excellent agreement. Within this range of Ca, the meniscus slope at a distance 10LS from the dynamic contact line is geometry independent, that is, does not vary with changes …


The Influence Of Acoustic Impedance Mismatch On Post-Stenotic Pulsed-Doppler Ultrasound Measurements In A Coronary Artery Model, S. A. Jones, H. Leclerc, George P. Chatzimavroudis, Y. H. Kim, N. A. Scott, Ajit P. Yoganathan Jan 1996

The Influence Of Acoustic Impedance Mismatch On Post-Stenotic Pulsed-Doppler Ultrasound Measurements In A Coronary Artery Model, S. A. Jones, H. Leclerc, George P. Chatzimavroudis, Y. H. Kim, N. A. Scott, Ajit P. Yoganathan

Chemical & Biomedical Engineering Faculty Publications

Acoustic impedance mismatch at the fluid-wall interface was shown to affect the spectra from an intravascular Doppler device in an in vitro model with a diameter typical of human coronary arteries. Measurements were obtained first under Poiseuille flow conditions with impedance mismatches of 0%, 7% and 12%, and then under stenosed conditions for the 0% and 7% mismatch cases. For the zero mismatch case, the Doppler spectra could be readily interpreted in terms of fluid mechanical phenomena. When mismatch was present, the spectra from Poiseuille flow exhibited multiple peaks which could not be directly related to the velocity profile. Also, …


Software Quality: Definitions And Strategic Issues, Ronan Fitzpatrick Jan 1996

Software Quality: Definitions And Strategic Issues, Ronan Fitzpatrick

Reports

This paper contains two sections relating to software quality issues. First, the various definitions of software quality are examined and an alternative suggested. It continues with a review of the quality model as defined by McCall, Richards and Walters in 1977 and mentions the later model of Boëhm published in 1978. Each of McCall's quality factors is reviewed and the extent to which they still apply in the late 1990s is commented on. The factors include, integrity, reliability, usability, accuracy, efficiency, maintainability, testability, flexibility,interface facility (interoperability), re-usability and transferability (portability). They are subdivided into external and internal quality factors. Interrelationships …


Theoretical Investigations Of Electro-Optical Synchonisation Of Self-Pulsating Laser Diodes, A. Egan, P. Rees, J. O'Gorman, M. Harley-Stead, Gerald Farrell, Joe Hegarty, P. Phelan Jan 1996

Theoretical Investigations Of Electro-Optical Synchonisation Of Self-Pulsating Laser Diodes, A. Egan, P. Rees, J. O'Gorman, M. Harley-Stead, Gerald Farrell, Joe Hegarty, P. Phelan

Articles

The synchronisation mechanism of selfpulsating laser diodes is determined and it is shown how this results in a frequency-dependent phase difference between the electrical input and optical output. The time-to-lock of the electrical input to the optical output is examined, particularly with regard to the importance of the initial phase difference between the signals. The effect of synchronisation on timing jitter in self pulsating lasers is also investigated.


Test 1647/1: Buhler Versatile 2180 Diesel, Nebraska Tractor Test Lab Jan 1996

Test 1647/1: Buhler Versatile 2180 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.


A Doctoral Degree In Aviation Science: The Need, Curriculum Content, And Other Considerations As Perceived By Aviation Educators Holding Doctoral Degrees, Barry Robert Beck Jan 1996

A Doctoral Degree In Aviation Science: The Need, Curriculum Content, And Other Considerations As Perceived By Aviation Educators Holding Doctoral Degrees, Barry Robert Beck

Theses and Dissertations

The primary purpose of this study was to determine if there is a need for a doctorate in aviation, what content areas should be included in the doctoral program, and what type of degree should an aviation doctoral program establish, as perceived by doctorally-prepared aviation educators. A two-round Delphi method was used to obtain a consensus from a group of doctorally-prepared experts on the content areas for doctoral programs in nonengineering aviation science. The panel of 100 experts were all doctorally-prepared and were members of the University Aviation Association, or if not members of the UAA, were working in collegiate …


Reducing Mud Using Highway-Type Filter Materials, Larry W. Turner Jan 1996

Reducing Mud Using Highway-Type Filter Materials, Larry W. Turner

Agricultural Engineering Extension Updates

Several beef and dairy producers across the country have been successful in dramatically reducing mud problems without resorting to the use of expensive concrete or pavement. A load-bearing material used in the highway industry can be placed in high animal traffic areas, on mounds, around feed bunks and in "transition " areas where animals move onto or off of concrete. The materials are of two basic types; 1) geotextiles, which are a porous filter-type material, and 2) polyethelye-type plastic grid material. Costs for installing the finished surface are about one-third the cost of concrete.


A Computational Method For Determining Global Fuel-No Rate Expressions. Part 1, Wei Chen, L Douglas Smoot, Thomas H. Fletcher, Richard D. Boardman Jan 1996

A Computational Method For Determining Global Fuel-No Rate Expressions. Part 1, Wei Chen, L Douglas Smoot, Thomas H. Fletcher, Richard D. Boardman

Faculty Publications

Global chemical reaction rates used in the modeling of NOx formation in comprehensive combustion codes have traditionally been obtained through correlation of experimental data. In this paper, a computational approach for obtaining global rates is presented. Several premixed flames were simulated, and sensitivity analysis of species concentration profiles was used to suggest global pathways in fuel-nitrogen conversion to NO. Based on these analyses, the global reaction rates were formulated. The predicted species concentration profiles and their derivatives were then used in the determination of the global rate constants. The correlation of rate constants for the two fuel-NO global rates …


Experiments In The Coordinated Control Of An Underwater Arm/Vehicle System, Timothy W. Mclain, Stephen M. Rock, Michael J. Lee Jan 1996

Experiments In The Coordinated Control Of An Underwater Arm/Vehicle System, Timothy W. Mclain, Stephen M. Rock, Michael J. Lee

Faculty Publications

The addition of manipulators to small autonomous underwater vehicles (AUVs) can pose significant control challenges due to hydrodynamic interactions between the arm and the vehicle. Experiments conducted at the monterey Bay Aquarium Research Institute (MBARI) using the OTTER vehicle have shown that dynamical interactions between an arm and a vehicle can be very significant. For the experiments reported in this paper, a single-link "arm" was mounted on OTTER. Tests showed that for 90-degree, two-second repetitive slews of the arm, the vehicle would move as much as 18 degrees in roll and 14 degrees in yaw when no vehicle control was …


Thermal Behavior Of Energy Storage System In A Cylindrical Tank, Walid Wagih Darwish Jan 1996

Thermal Behavior Of Energy Storage System In A Cylindrical Tank, Walid Wagih Darwish

Archived Theses and Dissertations

No abstract provided.


Approximation Of Biodegradation Rate Constants For Monoaromatic Hydrocarbons (Btex) In Ground Water, Todd Weidemeier, Matthew Swanson, John Wilson, Donald Kampbell, Ross Miller, Jerry Hansen Jan 1996

Approximation Of Biodegradation Rate Constants For Monoaromatic Hydrocarbons (Btex) In Ground Water, Todd Weidemeier, Matthew Swanson, John Wilson, Donald Kampbell, Ross Miller, Jerry Hansen

United States Environmental Protection Agency: Publications

Two methods were used to approximate site-specific biodegradation rates of monoaromatic hydrocarbons (benzene, toluene, ethylbenzene, and xylenes [BTEX]) dissolved in ground water. Both use data from monitoring wells and hydrologic properties of the aquifer to estimate a biodegradation rate constant that can be sued in ground water solute fate and transport models. The first method uses a biologically recalcitrant tracer in the ground water, associated with the hydrocarbon plume to normalize changes in concentration of BTEX under anaerobic conditions; attenuation of the tracer is attributed to dilution, sorption, and/or volatilization. Attenuation of BTEX in excess of the attenuation of the …


Managing Plague In Endangered Species Habitats, Frederick J. Harrison Jr. Jan 1996

Managing Plague In Endangered Species Habitats, Frederick J. Harrison Jr.

Vertebrate Pest Conference Proceedings: 17th (1996)

Plague is an endemic disease among field rodents in the southwestern United States. Epizootic outbreaks of this disease increase the risk of human infection where man comes into contact with infected rodents or their fleas. The risk is further increased when colonial rodents are involved, since these animals are usually found in large numbers and are often found in locations where people live, work, or enjoy recreational activities. Elimination of large numbers of susceptible rodents from a particular location following a plague epizootic usually results in a quiescent period when plague is neither a threat to those rodents moving into …


Nebraskan Work Patterns And Available Benefits, John C. Allen, Sam Cordes, Amy M. Smith, Matt Spilker, Amber Hamilton Jan 1996

Nebraskan Work Patterns And Available Benefits, John C. Allen, Sam Cordes, Amy M. Smith, Matt Spilker, Amber Hamilton

Rural Futures Institute: Publications

Includes

Executive Summary

Introduction

Methodology

Respondent Profile

Findings

Nebraskans and Work

Rural Nebraskans and Benefits


Application Of Autoregressive Moving Average Linear Prediction Filters To The Characterization Of Solar Wind-Magnetosphere Coupling, Carter N. Borst Jan 1996

Application Of Autoregressive Moving Average Linear Prediction Filters To The Characterization Of Solar Wind-Magnetosphere Coupling, Carter N. Borst

Theses and Dissertations

Linear prediction filtering techniques have been used in studying the coupling processes between the solar wind and magnetosphere. The magnetosphere is a complex, dynamic system with at least two independent coupling methods for energy input, driven and unloading. Linear models were built and tested on the Bargatze data set, consisting of over 70 days of geomagnetic indices and solar wind data ordered in 34 intervals of increasing geomagnetic activity. Linear filtering techniques employing single-and multiple-input, autoregressive models predicted values of the magnetic index AL from solar wind data. The impulse response curves of the AL-coupling function groups showed amplitude peaks …


An Electronic Surveillance And Control System For The Management Of Traffic On The Borman Expressway, Part Ii: Calibrating A Simulation Model, Mu-Han Wang, Michael J. Cassidy Jan 1996

An Electronic Surveillance And Control System For The Management Of Traffic On The Borman Expressway, Part Ii: Calibrating A Simulation Model, Mu-Han Wang, Michael J. Cassidy

JTRP Technical Reports

The purpose of this project was to calibrate a freeway simulation model to emulate traffic operating conditions on the Borman Expressway in Northwest Indiana. To replicate Borman operating conditions, the project adopted Integrated Traffic Simulation (INTRAS), a microscopic, stochastic freeway simulation model. Appropriate input data were developed on geometric, traffic and driver behavior information, based on physical measurements and other available data. The model was calibrated and statistical analysis were conducted to validate the accuracy of the results.


Automation Of Overweight Truck Permit Process For Michigan Trains, Robert K. Whitford, David P. Moffett Jan 1996

Automation Of Overweight Truck Permit Process For Michigan Trains, Robert K. Whitford, David P. Moffett

JTRP Technical Reports

Technical guidance was provided by Purdue University to the Indiana Department of Transportation regarding specific issues around automation of permit issuance for overweight and oversized vehicles on a specific piece of highway in Northwest Indiana. Supporting this guidance were four commentaries which were: 1. Functional Specification for Automation of Michigan Trains 2. Draft Commentary on Touch ToneTM/Voice Response System Security for Michigan Trains 3. Draft Commentary on Touch ToneTM/Voice Response System Vendor for Michigan Trains 4. Draft Commentary on Touch ToneTM/Voice Response System Auditability for Michigan Trains These are included as appendices to this report.


Borman Expressway Atms Equipment Evaluation, J. V. Krogmeier, Kumares C. Sinha, Michael P. Fitz, Srinivas Peeta, Shimon Y. Nof Jan 1996

Borman Expressway Atms Equipment Evaluation, J. V. Krogmeier, Kumares C. Sinha, Michael P. Fitz, Srinivas Peeta, Shimon Y. Nof

JTRP Technical Reports

An Advanced Traffic Management System (ATMS) is under development in northern Indiana by the Indiana Department of Transportation (INDOT) in conjunction with Hughes Transportation Management Systems. The study area comprises a sixteen mile segment of the heavily used Borman Expressway and its associated corridor; beginning at the Indiana/Illinois border and stretching east to the Indiana Toll Road interchange. The most important operational problem on the Borman is non-recurrent congestion, arising primarily through accidents and stalled vehicles. In order to mitigate the significant bottleneck delay problems due to non-recurrent congestion, INDOT is developing an ATMS for real-time incident detection and response …


Bioremediation Treatability Studies For Soils Containing Herbicides, Chemicals, And Petroleum Products, Loring F. Nies, Matthew B. Mesarch Jan 1996

Bioremediation Treatability Studies For Soils Containing Herbicides, Chemicals, And Petroleum Products, Loring F. Nies, Matthew B. Mesarch

JTRP Technical Reports

Leaking underground storage tanks are widespread throughout the United States. It is estimated that there are 1.4 million underground gasoline storage tanks in the United States, with as many as 75,000 to 100,000 that may be leaking. In Indiana alone, more than 3,500 of the 15,000 registered underground storage tank facilities have reported leaks. Conventional remediation methods often involve pump-and-treat schemes for contaminated water, and excavation and burial of contaminated soil in hazardous waste landfills. These methods increase the risk of exposure to pollutants for workers and local residents. Furthermore, these methods merely involve the transfer of pollutants from one …


Development Of A Procedure To Identify Aggregates For Bituminous Surfaces In Indiana, Douglas W. Bruner, Jung Chan Choi, Terry R. West Jan 1996

Development Of A Procedure To Identify Aggregates For Bituminous Surfaces In Indiana, Douglas W. Bruner, Jung Chan Choi, Terry R. West

JTRP Technical Reports

Adequate friction resistance is needed to prevent pavement slipperiness and to allow vehicles to stop in a reasonable distance. In stone mastic asphalt surfaces, friction resistance is mainly a function of the interaction between the aggregates exposed at the road surface and the vehicle tires. Performance of the aggregate is reduced over time by wear and polishing as a consequence of vehicular traffic. In this research a method to investigate aggregate performance based on physical, chemical and petrographic factors has been evaluated. The objective was to develop a laboratory method to test Indiana dolomite, limestone, sandstone, and gravel aggregates to …


Effective Scheduling Of Road And Bridge Closures: Phase 2, Kumares C. Sinha, Mithilesh K. Jha Jan 1996

Effective Scheduling Of Road And Bridge Closures: Phase 2, Kumares C. Sinha, Mithilesh K. Jha

JTRP Technical Reports

This research provides a study on work zone impact analysis. In case of multiple road closures, the network approach is used to find an effective scheduling such that the total user delay is reduced. A dynamic model for analyzing the work zone impact during the period when network is in transition state is also developed. A salient feature of the dynamic model is drives’ perception updating model, which incorporates availability and the quality of information as perceived by drivers.


Environmental Bioassay Evaluation Of Foundry Waste Residuals, Kenneth Chad Bastian, James E. Alleman Jan 1996

Environmental Bioassay Evaluation Of Foundry Waste Residuals, Kenneth Chad Bastian, James E. Alleman

JTRP Technical Reports

Although the constructive reuse of foundry residuals represents a decidedly beneficial goal with distinct economic and environmental benefits, potential end-users are nonetheless reluctant to use these residuals, given an inherent concern about potential unforeseen environmental liabilities. Results of foundry residual leachate characterization to date strongly suggest that many ferrous foundries are discarding sands whose quality is fully amenable to their future use with embankment construction and related high-volume highway development activities. In order to provide additional assurance as to the environmental impact of foundry residual reuse, the MicrotoxTM bioassay has been used to quantify the response of living organisms (e.g., …


Impact Analysis Of Vehicles On Ozone Generation In The Indianapolis Metropolitan Statistical Area, Robert Bertram Jacko, Ouattara Fatogoma Jan 1996

Impact Analysis Of Vehicles On Ozone Generation In The Indianapolis Metropolitan Statistical Area, Robert Bertram Jacko, Ouattara Fatogoma

JTRP Technical Reports

Motor vehicles are one of the largest emitters of ground-level ozone precursors – volatile organic compounds (VOCs) and nitrogen oxides (NO1) – into the atmosphere. Consequently, the Clean Air Act Amendment of 1990 requires the implementation of transportation control measures in order to reduce ground-level ozone precursor emissions and alleviate the ozone air quality problems. This research investigates the relative effects of motor vehicle emissions of VOCs and NO1 on hourly average concentrations of ground level ozone in the Indiana Airshed Model (UAM-IV). The findings of the research study are presented. This includes the results of the data analyses leading …


Indot Constructability Multimedia System Working Module, Bob G. Mccullouch Jan 1996

Indot Constructability Multimedia System Working Module, Bob G. Mccullouch

JTRP Technical Reports

Constructability can be defined as incorporating knowledge into the design product or designing so it is easier to construct. Transportation facilities have suffered from this problem, with INDOT no exception. The most important feature of any constructability program is capturing field examples, commonly referred to as “lessons learned,” and archiving and retrieving them into future projects that are either similar or have similar conditions in order to eliminate or prevent the same mistakes from occurring again. A mechanism or tool that can perform this task would be a valuable asset for INDOT. A previous JHRP project title “An INDOT Lessons …


Locating The Drainage Layer For Bituminous Pavements In Indiana, Hossam Farouk. Hassan, Thomas D. White Jan 1996

Locating The Drainage Layer For Bituminous Pavements In Indiana, Hossam Farouk. Hassan, Thomas D. White

JTRP Technical Reports

Pavement subsurface drainage and its effect on pavement performance has been a subject of interest since the 18th and 19th centuries. With no doubt the detrimental effects of heavy wheel loads on pavements with saturated base material is a significant factor. The consequence of subsurface water on pavement performance includes premature rutting, cracking, faulting, and increased roughness, all of which lead to a decrease in serviceability. This research study involves the evaluation of the drainage performance of three section configurations. The sections were built with a difference in the filter as well as the drainage layer. Indiana #5D, and #53 …


Seismic Evaluation Of Highway Bridges - Phase 1, J. A. Ramirez, Austin D. Pan, Frank Thompson Mwakasisi Jan 1996

Seismic Evaluation Of Highway Bridges - Phase 1, J. A. Ramirez, Austin D. Pan, Frank Thompson Mwakasisi

JTRP Technical Reports

The primary objective of the study was to establish the guidelines for screening, assessing, and ranking Indiana bridges for seismic upgrade. The outcome of the study is a complete strategy for the detailed structural assessment of Indiana highway bridges subjected to seismic forces. The structural evaluation is conducted using a nonlinear time-history analysis of the bridge for simulated or actual records. The specific soil conditions at the site are accounted in terms of the ground motion. From the time history analysis the maximum structural response including displacements, bending moments, shear and axial forces are computed. A weighted evaluation of the …