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Articles 179701 - 179730 of 197988

Full-Text Articles in Engineering

Summary Of Results Of 1990 Field And Laboratory Evaluations Of Pavement Marking Materials (Sashto Regional Test Facility), Kentucky Transportation Center Jul 1991

Summary Of Results Of 1990 Field And Laboratory Evaluations Of Pavement Marking Materials (Sashto Regional Test Facility), Kentucky Transportation Center

Kentucky Transportation Center Research Report

This report summarizes the results of data collected as part of the 1990 field and laboratory evaluations of pavement marking materials for the SASHTO Regional Test Facility. The purpose of the Regional Test Facility (RTF) is to minimize the amount of field and laboratory research testing of specific types of materials. This is accomplished by combining efforts in an organized manner to reduce the monetary and man-hour requirements of both the states and industry. A RTF for the twelve SASHTO states was approved at the 1988 SASHTO convention. The twelve SASHTO states are Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, …


Engineering Estimates And Fhwa Accuracy Criterion, David Q. Hunsucker Jul 1991

Engineering Estimates And Fhwa Accuracy Criterion, David Q. Hunsucker

Kentucky Transportation Center Research Report

The Federal Highway Administration requires the construction cost estimate of the highway engineer to be a projection of the low bid, and be within +/- 10 percent of the low bid for at least 50 percent of the projects awarded. Construction cost estimates developed by the Estimating Staff of the Kentucky Department of Highways have not always met this criterion in years past.

The Estimating Staff of the Kentucky Department of Highways use an actual cost approach to generate construction cost estimates. It was concluded that the Department's estimating staff possess the ability to do very thorough and accurate work. …


Protective Coating Program Final Report, James E. Funk, Theodore Hopwood Ii, Donald G. Hartman, Christopher M. Oberst, Rick D. Saylor, Anantha R. Sethuraman Jul 1991

Protective Coating Program Final Report, James E. Funk, Theodore Hopwood Ii, Donald G. Hartman, Christopher M. Oberst, Rick D. Saylor, Anantha R. Sethuraman

Kentucky Transportation Center Research Report

This program consists of two primary segments: 1) installing an environmental monitoring station at the Toyota marshalling yard at Georgetown, Kentucky, and 2) conducting laboratory and field tests of paint and wax-coated painted specimens to assess the protection against acid rain damage afforded by a protective transient coating.


Integrated System Identification And Adaptive State Estimation For Control Of Flexible Space Structures, Chung-Wen Chen Jul 1991

Integrated System Identification And Adaptive State Estimation For Control Of Flexible Space Structures, Chung-Wen Chen

Mechanical & Aerospace Engineering Theses & Dissertations

Accurate state information is crucial for control of flexible space structures in which the state feedback strategy is used. The performance of a state estimator relies on accurate knowledge about both the system and its disturbances, which are represented by system model and noise covariances respectively. For flexible space structures, due to their great flexibility, obtaining good models from ground testing is not possible. In addition, the characteristics of the systems in operation may vary due to temperature gradient, reorientation, and deterioration of material, etc. Moreover, the disturbances during operation are usually not known. Therefore, adaptive methods for system identification …


Parallel-Vector Computation For Geometrically Nonlinear Frame Structural Analysis And Design Sensitivity Analysis, Majdi A. Baddourah Jul 1991

Parallel-Vector Computation For Geometrically Nonlinear Frame Structural Analysis And Design Sensitivity Analysis, Majdi A. Baddourah

Civil & Environmental Engineering Theses & Dissertations

Parallel-vector algorithms are presented for solving the geometrically nonlinear structural problems and obtaining design sensitivity information. A new algorithm is also presented for parallel generation and assembly of the finite element stiffness and mass matrices. The presented assembly algorithm is based on a node-by-node approach rather than the more conventional element-by-element approach. Three different methods, Newton Raphson, Modified Newton Raphson, and the BFGS, are used in the analysis of the nonlinear structural problems. A study is made to determine the performance of each of the mentioned methods in a parallel-vector computer environment. Medium to large-scale, practical problems are solved to …


Bs News Jul 1991

Bs News

Building Services Engineering

No abstract provided.


An Experimental And Analytical Investigation Of Wing Flutter On A Trial Rotor V/Stol Aircraft, David L. Soistmann Jul 1991

An Experimental And Analytical Investigation Of Wing Flutter On A Trial Rotor V/Stol Aircraft, David L. Soistmann

Mechanical & Aerospace Engineering Theses & Dissertations

A wind tunnel model based on a trail rotor vehicle concept was tested for wing flutter in the subsonic flow regime. The wind tunnel model was flutter tested in the forward flight mode only. From this test it was determined that this conceptual vehicle may be susceptible to wing flutter. However, the flutter encountered was not catastrophic but was of the limited amplitude type. The trailing rotor blades were found to have a positive aerodynamic damping effect on flutter. The flutter mechanism for each flutter point was due to a coupling of the first wing bending and first wing torsion …


An Experimental Study On Anisotropic Behavior Of Granular Materials, Jong Woon Choi Jul 1991

An Experimental Study On Anisotropic Behavior Of Granular Materials, Jong Woon Choi

Civil & Environmental Engineering Theses & Dissertations

Two types of mixtures of glass bead assemblies (large beads and small beads) were used to investigate the source of the anisotropy of granular materials in volume change behaviors during shearing process. Most tests (7 series) were conducted in the conventional triaxial device while a series of the experiments were in the hollow cylinder test device. All the specimens were first isotropically consolidated up to 137.9 kPa and were subjected to shearing in triaxial compression and triaxial extension modes with a constant effective mean normal stress (137.9 kPa). The test results indicated that all the specimens had a strong but …


Purification And Characterization Of The Prostate Cancer-Associated Antigen: 7e11-C5, Qi Feng Jul 1991

Purification And Characterization Of The Prostate Cancer-Associated Antigen: 7e11-C5, Qi Feng

Theses and Dissertations in Biomedical Sciences

A murine monoclonal antibody (MAb), 7E11-C5, recognizes a prostate organ-specific antigen. Under reducing conditions, the 7E11-C5 antigen exhibited major 100-Kd and minor 70-Kd bands, suggesting that the antigen comprises two peptide chains. The antigen was detected in pooled normal human seminal plasma, xenograft tissue extract of a prostate adenocarcinoma cell line, LNCaP, and tissue extracts of benign prostatic hyperplasia (BPH) and prostate carcinomas, but was not identified in any of the non-prostate tissue extracts tested. Antibodies of the three major prostate-associated antigens (prostatic acid phosphatase (PAP), prostate specific antigen (PSA) and prostate secretory protein (PSP)) were unable to block the …


On Shock Capturing For Liquid And Gas Media, Tze Jang Chen Jul 1991

On Shock Capturing For Liquid And Gas Media, Tze Jang Chen

Mathematics & Statistics Theses & Dissertations

The numerical investigation of shock phenomena in gas or liquid media where a specifying relation for internal energy is absent poses special problems. Classically, for gas dynamics the usual procedure is to employ a splitting scheme to remove the source terms from the Euler equations, then up-wind biased shock capturing algorithms are built around the Riemann problem for the system which remains. However, in the case where the Euler equations are formulated in the term of total enthalpy, a technical difficulty associated with equation splitting forces a pressure time derivative to be treated as a source term. This makes it …


A Comparative Analysis Of The Efficacy Of Zero-Order, First-Order And Monod Kinetic Models In Representing Raw Aerobic Biodegradation Data, Andrew I. Bakun Jun 1991

A Comparative Analysis Of The Efficacy Of Zero-Order, First-Order And Monod Kinetic Models In Representing Raw Aerobic Biodegradation Data, Andrew I. Bakun

Theses

A total of 148 raw aerobic biodegradation data sets from batch and continuous stirred-tank reactors were extracted from the open literature and previous NJIT MS theses. Kinetic analysis of each of these data sets was performed with respect to the following commonly used empirical models: (1) zero-order, (2) first-order, and (3) Monod. Two constant-biomass versions of each model were evaluated; one in which So (i.e., the boundary condition for substrate concentration at time equal to zero) was assumed to be equal to the measured value of the initial substrate concentration and the other in which So was treated as a …


Simulation Study Of Signal Coupling For Monolithic Gaas 8-12 Micron Direct Injection Mqw Image Sensor, Lei Zhang Jun 1991

Simulation Study Of Signal Coupling For Monolithic Gaas 8-12 Micron Direct Injection Mqw Image Sensor, Lei Zhang

Theses

The simulation of signal coupling for a single pixel of a monolithic 8-12 micron GaAs/A1GaAs direct injection MQW infrared image sensor with 100% fill factor has been performed by using PISCES-IIB and PSPICE simulators. A vertical structure with the readout circuit built on the back of MQW was adopted for simulations. Both the static and transient characteristics were analyzed by simulation. The simulation was used to verify the doping profiles and device parameters for the n-GaAs MESFETs used in the read-out circuit.

The simulation result is as follow:

(1) A 900A thick p-GaAs (p=1016/cm3) substrate for GaAs MESFETs …


Optimal Sustained-Yield Groundwater Pumping Strategy For The East Shore Area, Utah, Shu Takahashi, Richard C. Peralta Jun 1991

Optimal Sustained-Yield Groundwater Pumping Strategy For The East Shore Area, Utah, Shu Takahashi, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

Optimal sustained-yield pumping strategies were developed for the irrigated and industrialized eastern shore of the Great Salt Lake. The combined optimization and simulation model contains steady-state, finite difference, quasi-three-dimensional, groundwater flow equations embedded as constraints. The model computes the optimal spatial distribution of sustainable annual groundwater pumping rates for alternative scenarios. The addressed aquifer is a multilayer and confined/unconfined (linear/nonlinear) system. The research can help manage water in the study area, where the demand for water of sufficient quality and quantity is increasing due to urbanization.


Tractor Museum Committee Establishment 1991, Tractor Museum Jun 1991

Tractor Museum Committee Establishment 1991, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

No abstract provided.


Cognitive Learning Styles And Their Relation To Air Traffic Control Screening And Training, Vincent P. Galotti Jun 1991

Cognitive Learning Styles And Their Relation To Air Traffic Control Screening And Training, Vincent P. Galotti

Master's Theses - Daytona Beach

The purpose of this study was to show a relationship between the type of cognitive learning style that an individual possesses and their subsequent success at simulated air traffic control practical exercises. Kolb's Learning Style Inventory was utilized to determine dominant learning styles of 30 college students enrolled in a laboratory-based air traffic control course. The instrument was administered during the first day of classes in the Fall of 1990. Students were placed in one of four groups for statistical purposes according to learning style. The scores of simulated micro-computer based air traffic control practical exercises given at semester's end …


Simultaneous Extraction And Sorption Under Supercritical Conditions, Ş. Uğur Akman Jun 1991

Simultaneous Extraction And Sorption Under Supercritical Conditions, Ş. Uğur Akman

USF Tampa Graduate Theses and Dissertations

Supercritical Exsorption (SCEXS), simultaneous supercritical extraction and sorption (adsorption and/or desorption), is a novel process which may have potential for applications in chemical, biochemical and environmental engineering. The system of interest consists of a fixed-bed packed with an adsorbent (e.g., activated carbon or catalyst) through which a so~vent stream (e.g., supercritical carbon dioxide) and a feed stream (e.g., an aqueous stream with low concentration of solute such as phenol) flow countercurrently.

In this work, the theoretical foundations of SCEXS have been established through distributed-parameter modeling which enables phenomenal description of several probable three-phase mass transfer dynamics taking place in the …


Investigation Of Real-Time Optical Scanning Holography, Bradley D. Duncan Jun 1991

Investigation Of Real-Time Optical Scanning Holography, Bradley D. Duncan

Electro-Optics and Photonics Faculty Publications

Real-time holographic recording using an optical heterodyne scanning technique was proposed by Poon in 1985. The first part of this dissertation provides a detailed theoretical treatment of the technique, based on a Gaussian beam analysis. Topics to be addressed include the derivations of the optical transfer function (OTF) and impulse response of the scanning holographic recording system, reconstructed image resolution and magnification, methods of carrier frequency hologram generation and experimental verification of the recording technique based on careful measurements of a hologram corresponding to a simple transmissive slit. Furthermore, computer simulations are presented pertaining to the incoherent nature of the …


The Use Of A High Level Cfd Code In Engineering Education, J.E.S. Venart, P. Lemieux, A.C.M. Sousa, D. Tatchell Jun 1991

The Use Of A High Level Cfd Code In Engineering Education, J.E.S. Venart, P. Lemieux, A.C.M. Sousa, D. Tatchell

Mechanical Engineering

An advanced multipurpose Computational Fluid Dynamics (CFD) code, FloSYS, developed for use in a CAD/CAE environment has been utilized in undergraduate and graduate courses in heat transfer. Problems are introduced at an introductory level in: -steady 2- and 3-dimensional conduction, -transient 1-, 2-, and 3-dimensional conduction, -free convective cavity flow with conjugate heat transfer, and -turbulent flows with heat transfer. More sophisticated problems, related to the use of porous media concepts for modelling heat exchangers, and compartment fire modelling are introduced at a more senior level. After one year's experimental use, the CFD code is being recommended for use in …


High-Frequency Electrooptic Fabry-Perot Modulators, R. J. Simes, R. H. Yan, C. C. Barron, Dennis J. Derickson, D. G. Lishan, Judy R. Karin, L. A. Coldren, M. Rodwell, S. Elliott, B. Hughes Jun 1991

High-Frequency Electrooptic Fabry-Perot Modulators, R. J. Simes, R. H. Yan, C. C. Barron, Dennis J. Derickson, D. G. Lishan, Judy R. Karin, L. A. Coldren, M. Rodwell, S. Elliott, B. Hughes

Electrical Engineering

Electrooptic modulators built from GaAs/AlxGa1-xAs Fabry-Perot cavities operating up to 6.5 GHz are reported. The measured frequency response agrees well with the one predicted using an equivalent circuit model derived from high-speed electrical measurements. The parasitic capacitances have been reduced to approximately 30 fF by fabricating the devices on semi-insulating GaAs substrates and integrating them with on-wafer bound pads which have dimensions compatible with microwave coplanar probes.


The Calendar - June 1991, Nova University Jun 1991

The Calendar - June 1991, Nova University

The Calendar

No abstract provided.


A Prolog System For Converting Vhdl-Based Models To Generalized Extraction System (Ges) Rules, Michael A. Dukes, Frank M. Brown, Joanne E. Degroat Jun 1991

A Prolog System For Converting Vhdl-Based Models To Generalized Extraction System (Ges) Rules, Michael A. Dukes, Frank M. Brown, Joanne E. Degroat

AFIT Documents

With the advent of VHDL accurate documentation of hardware designs is a practical reality. In the past, schematics were typically used for documentation of hardware designs. However, these schematics would usually become obsolete as the hardware design was being constructed. Deviations in the hardware design would sometimes not be reflected in the schematics. For design groups, failure to update schematics could lead to different parts of a hardware design becoming incompatible. A system to ensure compliance of hardware with its VHDL documentation is presented in this paper. The system, vhdl2ges, is meant to help guide the development of hardware by …


Mosfet Audio Amplifier, Jeff Argast Jun 1991

Mosfet Audio Amplifier, Jeff Argast

Undergraduate Honors Capstone Projects

My senior project is an audio amplifier utilizing MOSFETs as the output transistors to drive the speaker. Within this document I cover the details of designing an amplifier, and the methods used to build it.

The most important part of the project is the output stage. In this section I chose MOSFETs over BJTs. Several advantages ensued from this decision, resulting in a simple design.

Further, the transformer must be able to supply the necessary currents for the transistors. Because large musical peaks are possible, resulting in sizable power surges, I had to obtain a large transformer with adequate specifications. …


Investigation Of Air Distribution System Leakage And Its Impacts In Central Florida Homes, Florida Solar Energy Center, James B. Cummings Jun 1991

Investigation Of Air Distribution System Leakage And Its Impacts In Central Florida Homes, Florida Solar Energy Center, James B. Cummings

FSEC Energy Research Center®

Testing for air leakage in air distribution systems was done in 160 central Florida homes. Tracer gas tests found that infiltration rates were three times greater when the air handler was operating that when it was off, indicating that there are large leaks in the air distribution system. Infiltration averaged 0.91 air changes per hour (ach) with the air handler (AH) operating continuously and 0.28 ach with the AH off. Return leaks were measured by tracer gas and found to average 10.7% of AH total flow. House airtightness, in 99 of these homes, determined by blower door testing, averaged 12.7 …


Acuta Enews June 1991, Vol. 20, No. 6 Jun 1991

Acuta Enews June 1991, Vol. 20, No. 6

ACUTA Newsletters

In This Issue

Panel to focus on fraud

Interactive video bandwidth

Aggregator requirements

Telex can still be useful

Penn State still pioneering

Positions availabe


The Difficulty Of Random Attribute Noise, Sally A. Goldman, Robert H. Sloan Jun 1991

The Difficulty Of Random Attribute Noise, Sally A. Goldman, Robert H. Sloan

All Computer Science and Engineering Research

This paper studies the robustness of pac learning algorithms when the instance space is {0,1}n, and the examples are corrupted by purely random noise affecting only the instances (and not the labels). In the past, conflicting results on this subject have been obtained-- the "best agreement" rule can only tolerate small amounts of noise, yet in some cases large amounts of noise can be tolerated. We show the truth lies somewhere between the two alternatives. For uniform attribute noise, in which each attribute is flipped independently at random with the same probability, we present an algorithm that pac learns monomial …


Dna Mapping Algorithms: Abstract Data Types - Concepts And Implementation, Will Gillett, Liz Hanks Jun 1991

Dna Mapping Algorithms: Abstract Data Types - Concepts And Implementation, Will Gillett, Liz Hanks

All Computer Science and Engineering Research

The conceptual aspects of and the implementation details of a set of self-identifying abstract data types (ADT) are described. Each of the ADTs constitutes a specific class of object, upon which a set of well-defined access functions is available. The intent of these ADTs is to supply a paradigm in which a class of object is available for manipulation, but in which the underlying implementation is hidden from the application programmer. Specific ADTs are the described in some detail. The tagged architecture used to achieve the self-identifying property of the ADTs is presented, and a set of required system-backbone access …


Computational Learning Theory Lecture Notes For Cs 582 Spring Semester, 1991, Sally A. Goldman Jun 1991

Computational Learning Theory Lecture Notes For Cs 582 Spring Semester, 1991, Sally A. Goldman

All Computer Science and Engineering Research

This manuscript is a compilation of lecture notes from the graduate level course CS 582, "Computational Learning Theory," I taught at Washington University in the spring of 1991. Students taking the course were assumed to have background in the design and analysis of algorithms as well as good mathematical background. Given that there is no text available on this subject, the course material was drawn from recent research papers. I selected the first twelve topics and the remainder were selected by the students from a list of provided topics. This list of topics is given at the end of these …


Pump Polarization Effects In Cw Dye Lasers, Lee W. Casperson, W. J. Sandle, A. C. Wilson, D. M. Warrington, R. J. Ballagh Jun 1991

Pump Polarization Effects In Cw Dye Lasers, Lee W. Casperson, W. J. Sandle, A. C. Wilson, D. M. Warrington, R. J. Ballagh

Electrical and Computer Engineering Faculty Publications and Presentations

The effects of pump polarization on the performance of cw dye lasers have been investigated. A recently developed semiclassical model for synchronously pumped mode‐locked dye lasers is adapted to the problem of cw dye‐laser oscillation, and analytic expressions are obtained for the relationship between the pump power, pump polarization, and dye‐laser output power. The theoretical results are compared with experimental data obtained using an argon‐laser‐pumped rhodamine 6G dye laser.


Spaceborne Radar Measurement Of Wind Velocity Over The Ocean-An Overview Of The Nscat Scatterometer System, David G. Long, F. M. Naderi, Michael H. Freilich Jun 1991

Spaceborne Radar Measurement Of Wind Velocity Over The Ocean-An Overview Of The Nscat Scatterometer System, David G. Long, F. M. Naderi, Michael H. Freilich

Faculty Publications

Scatterometry and scatterometer design issues are reviewed. The design of the NASA Scatterometer (NSCAT) to be flown on the Japanese ADEOS mission is presented. Building on Seasat experience, the NSCAT system includes several enhancements, such as three antenna azimuths in each of two swaths, and an onboard digital Doppler processor to allow backscatter measurements to be colocated everywhere within the orbit. These enhancements will greatly increase the quality of the NSCAT wind data. The ground processing of data is discussed, and scatterometers of the next decade are briefly described.


Tensile Behavior Of Hybrid Woven-Fabric-Composites, Hussein M Massoud Jun 1991

Tensile Behavior Of Hybrid Woven-Fabric-Composites, Hussein M Massoud

Archived Theses and Dissertations

No abstract provided.