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1991

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Articles 391 - 420 of 1363

Full-Text Articles in Engineering

Fabrication Of High-Conductivity, Transparent Electrodes With Trenched Metal Bus Lines, Otto J. Gregory, R. J. Zeto, E. Hryckowian, K. A. Burbank Jul 1991

Fabrication Of High-Conductivity, Transparent Electrodes With Trenched Metal Bus Lines, Otto J. Gregory, R. J. Zeto, E. Hryckowian, K. A. Burbank

Chemical, Biomolecular, and Materials Engineering Faculty Publications

A novel transparent electrode system has been developed for thin film electroluminescent displays in which the poor conductivity of the indium-tin-oxide (ITO) electrodes has been augmented by high-conductivity buses of thick aluminum or silver. The augmented electrode system consists of patterned ITO electrodes, 200 Fm wide, centered over narrow aluminum or silver lines 40 ~m wide and separated by an intermediate diffusion barrier film of titanium to promote adhesion to the ITO and prevent blackening of the main ITO electrode by interfacial reactions. The sheet resistances of the augmented ITO electrodes (A1-Ti-ITO and Ti-Ag-Ti-ITO) were lowered by two orders of …


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 …


Conceptual Design Of Dual Cam Mechanisms Using Graph Theory, Raymond Lee Mcclendon Jul 1991

Conceptual Design Of Dual Cam Mechanisms Using Graph Theory, Raymond Lee Mcclendon

Mechanical & Aerospace Engineering Theses & Dissertations

This paper presents the theory of graphs and how they can be applied to the conceptual design of dual-cam mechanisms. The graph theory was used to validate the results of previous authors (Hain and Pryor). Several applications of dual cam mechanisms are reviewed.

Algorithms using a process of bit mapping were used to developed all possible non-isomorphic graphs for various classes of mechanisms. A classification method was developed using common occurring substructures found in the graphs. This classification scheme was used for conversion of graphs into schematics. Once the results of Hain were verified, the investigation turned to mechanisms with …


Finite Element Analysis Of Nonlinear Panel Flutter Of Rectangular Composite Plates Under A Uniform Thermal Load, Lain Ross Dixon Jul 1991

Finite Element Analysis Of Nonlinear Panel Flutter Of Rectangular Composite Plates Under A Uniform Thermal Load, Lain Ross Dixon

Mechanical & Aerospace Engineering Theses & Dissertations

A finite element formulation is developed to analyze large-amplitude panel flutter of arbitrarily laminated composite plates subjected to a uniform temperature change. The plates considered are anisotropic composite, thin rectangular panels. The aerodynamic pressure load is modeled through the use of the first-order piston theory. The equations of motion for the oscillating plate are determined from the principle of virtual work. Two different solution procedures are given to determine the panel motions. The first procedure, which considers only the aerodynamic load, solves the panel limit-cycle motions by employing the linearized updated-mode with a nonlinear time function (LUM/NTF) approximation. The second …


Application Of Sensitivity Analysis To The Euler Equations, Vamshi Mohan Korivi Jul 1991

Application Of Sensitivity Analysis To The Euler Equations, Vamshi Mohan Korivi

Mechanical & Aerospace Engineering Theses & Dissertations

An approximation method is presented for efficiently predicting the changes which occur in a steady-state numerical solution of the Euler equations as a consequence of a small change in the geometric shape of the domain. The method is extended to develop a general procedure for calculating aerodynamic sensitivity derivatives with respect to variations of geometric shape. The techniques are implemented using an upwind cell centered finite volume formulation, and are applied to two test cases, (1) a subsonic nozzle (M = 0.85), and (2) a supersonic inlet (M = 2.0). Conventional numerical solutions are first obtained for flow …


Dynamic Test/Analysis Correlation Using Reduced Analytical Models, Paul E. Mcgowan Jul 1991

Dynamic Test/Analysis Correlation Using Reduced Analytical Models, Paul E. Mcgowan

Mechanical & Aerospace Engineering Theses & Dissertations

Test/analysis correlation is an important aspect of the verification of analysis models which are used to predict on-orbit response characteristics of large space structures. This thesis summarizes the study of using reduced analysis models for performing dynamic test/analysis correlation. The reduced test-analysis model (TAM) has the same number of degrees-of-freedom (DOF) as the number of test measurements. This allows the direct comparison of modal parameters between ground vibration test results and finite element model (FEM) analysis results. The TAM can also be used for pre-test analysis and to aid in the post-test mathematical model updating process.

Herein, four methods for …


Investigation Of Radiative Interactions In Supersonic Chemically Reacting Channel Flows, Almuttil M. Thomas Jul 1991

Investigation Of Radiative Interactions In Supersonic Chemically Reacting Channel Flows, Almuttil M. Thomas

Mechanical & Aerospace Engineering Theses & Dissertations

Analyses and numerical procedures are presented to investigate the radiative interactions of absorbing emitting species in chemically reacting supersonic flow in various ducts. The two-dimensional time dependent Navier-Stokes equations in conjunction with radiative flux equation are used to investigate supersonic flows undergoing finite rate chemical reaction in a hydrogen air system. The specific problem considered is the flow of premixed radiating gas between parallel plates. Specific attention is directed in investigating the radiative contribution of H2O, OH and NO under realistic physical and flow conditions. Results are presented for the radiative flux obtained for different gases and for various combination …


Parallel-Vector Design Sensitivity Analysis In Structural Dynamics, Yongxing Zhang Jul 1991

Parallel-Vector Design Sensitivity Analysis In Structural Dynamics, Yongxing Zhang

Civil & Environmental Engineering Theses & Dissertations

In this study, the design sensitivity analysis is for the purpose of providing constraint derivative information for structural optimization under dynamic loads. Various existing formulations are reviewed, and the direct differentiation method is justified as the best one for design sensitivity analysis in structural dynamics. An alternative formulation for design sensitivity analysis with direct differentiation method is developed. The alternative formulation works efficiently with the reduced system of dynamic equations, and it eliminates the need for expensive and complicated eigenvector derivatives, which is required in the existing reduced system formulation. The relationship of the alternative formulation and the existing reduced …


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 …


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 …


A Robust Approach To Human-Computer Interface Design Using The Taguchi Method, Billie Mitchell Reed Jul 1991

A Robust Approach To Human-Computer Interface Design Using The Taguchi Method, Billie Mitchell Reed

Engineering Management & Systems Engineering Theses & Dissertations

The application of Dr. Genichi Taguchi's approach for design optimization, called Robust Design, to the design of human-computer interface software is investigated. The Taguchi Method is used to select a near optimum set of interface design alternatives to improve user acceptance of the resulting interface software product with minimum sensitivity to uncontrollable noise caused by human behavioral characteristics.

Design alternatives for interaction with personal micro-computers are identified. Several important and representative alternatives are chosen as design parameters for the Taguchi matrix experiment. A noise field with three human behavioral characteristics as noise factors were chosen as a representative noise array. …


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.


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, …


Converting Binary Thresholds Networks Into Equivalent Symmetric Networks, Gadi Pinkas Jul 1991

Converting Binary Thresholds Networks Into Equivalent Symmetric Networks, Gadi Pinkas

All Computer Science and Engineering Research

We give algorithms to convert any network of binary threshold units (that does not oscillate) into an equivalent network with symmetric weight matrix (like Hopfield networks [Hopfield 82] or Boltzmann machines [Hinton, Sejnowski 88]). The motivation for the transformation is dual: a) to demonstrate the expressive power of symmetric networks; i.e. binary threshold networks (that do not oscillate) are subsumed in the energy minimization paradigm; 2) to use network modules (developed for the spreading activation paradigm for example), within the energy minimization paradigm. Thus optimization [Tank, Hopfield 88] and approximation of hard problems can be combined with efficient modules, that …


Composition, Superposition, And Encapsulation In The Formal Specification Of Distributed Systems, Kenneth J. Goldman Jul 1991

Composition, Superposition, And Encapsulation In The Formal Specification Of Distributed Systems, Kenneth J. Goldman

All Computer Science and Engineering Research

Composition, superposition, and encapsulation are important techniques that work well together for designing large distributed software systems. Composition is a symmetric operator that allows system components to communicate with each other across module boundaries. Superposition is an asymmetric relationship that allows one system component to observe the state of another. Encapsulation is the ability to define the reason about the behavior of a module in terms of a well-defined boundary between that module and its environment, while hiding the internal operations of that module. In this paper, the I/O automation model of Lynch and Tuttle is extended to permit superposition …


The Spectrum Simulation System: A Formal Approach To Distributed Algorithm Development Tools, Kenneth J. Goldman Jul 1991

The Spectrum Simulation System: A Formal Approach To Distributed Algorithm Development Tools, Kenneth J. Goldman

All Computer Science and Engineering Research

We present the Spectrum Simulation System, a new research tool for the design and study of distributed algorithms. Based on the formal Input/Output Automation model of Lynch and Tuttle, Spectrum allows one to express distributed algorithms as collections of I/O automata and simulate them directly in terms of the semantics of that model. This permits integration of algorithm specification, design, debugging, analysis, and proof of correctness within a single formal framework that is natural for describing distributed algorithms. Spectrum provides a language for expressing algorithms as I/O automata, a simulator for generating algorithm executions, and a graphics interface for constructing …


An Access Protection Solution For Heavy Load Unfairness In Dqdb, Lakshmana N. Kumar, Andreas D. Bovopoulos Jul 1991

An Access Protection Solution For Heavy Load Unfairness In Dqdb, Lakshmana N. Kumar, Andreas D. Bovopoulos

All Computer Science and Engineering Research

This paper discusses the unfairness issue arising in a 802.6 DQDB network at high loads-- when the traffic demand to a bus exceeds the capacity of that bus. As per the 802.6 protocol, at heavy loads, the end nodes along a bus experience longer delays than the other nodes. The origin and remedy of this heavy load unfairness is discussed. An access control scheme is proposed as a solution. The comparison of the proposed scheme with 802.6 protocol is presented. The simulation results and performance characteristics are discussed under several types of loads. With symmetric load conditions under the proposed …


Center For Computer And Information Sciences Master Of Science In Computer Science Summer Courses 1991, Nova Southeastern University Jul 1991

Center For Computer And Information Sciences Master Of Science In Computer Science Summer Courses 1991, Nova Southeastern University

College of Engineering and Computing Course Catalogs

No abstract provided.


Center For Computer And Information Sciences Master Of Science In Computer Information Systems Summer Courses 1991, Nova Southeastern University Jul 1991

Center For Computer And Information Sciences Master Of Science In Computer Information Systems Summer Courses 1991, Nova Southeastern University

College of Engineering and Computing Course Catalogs

No abstract provided.


Engineering Soils Map Of Washington County, Indiana, Wei-Yao Chen Jul 1991

Engineering Soils Map Of Washington County, Indiana, Wei-Yao Chen

JTRP Technical Reports

No abstract provided.


Bs News Jul 1991

Bs News

Building Services Engineering

No abstract provided.


Interaction Of Sodium, Sulfur, And Silica During Coal Combustion, Thomas A. Erickson, Douglas K. Ludlow, Steven A. Benson Jul 1991

Interaction Of Sodium, Sulfur, And Silica During Coal Combustion, Thomas A. Erickson, Douglas K. Ludlow, Steven A. Benson

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Interaction of Sodium, Sulfur, and Silica at Conditions Typical in a Pulverized Coal Furnace Was Investigated by using Both Model Mixtures and a Synthetic Coal. the Model Mixtures Consisted of Selected Inorganic Constituents that Were Well Mixed in Proportions Typically Found in Low-Rank Coal. the Synthetic Coal Consisted of a Furfuryl Alcohol Polymer with Appropriate Amounts of Sodium, Sulfur, and Silica to Duplicate the Characteristics of Low-Rank Coal. the Model Mixtures and Synthetic Coal Were Burned in a Laminar Flow (Drop-Tube) Furnace at 900, 1100, 1300, and 1500 °C and Residence Times of 0.1,0.5,1.5, and 2.4 S. the Resulting …


Transmission Ellipsometry On Transparent Unbacked Or Embedded Thin Films With Application To Soap Films In Air, R. M.A. Azzam Jul 1991

Transmission Ellipsometry On Transparent Unbacked Or Embedded Thin Films With Application To Soap Films In Air, R. M.A. Azzam

Electrical Engineering Faculty Publications

The ratio ρt = Tp/Ts of the complex amplitude transmission coefficients for the p and s polarizations of a transparent unbacked or embedded thin film is examined as a function of the film thickness-to-wavelength ratio d/λ and the angle of incidence Φ for a given film refractive index N. The maximum value of the differential transmission phase shift (or retardance), Δt = argρt, is determined, for given N and Φ, by a simple geometrical construction that involves the iso-Φ circle locus of ρt in the complex plane. The …


Rapid Display Of Radiographic Images, Jerome R. Cox Jr., Stephen M. Moore, Robert A. Whitman, G. James Blaine, R. Gilbert Jost, L. Magnus Karlsson, Thomas L. Monsees, Gregory L. Hansen, Timothy C. David Jul 1991

Rapid Display Of Radiographic Images, Jerome R. Cox Jr., Stephen M. Moore, Robert A. Whitman, G. James Blaine, R. Gilbert Jost, L. Magnus Karlsson, Thomas L. Monsees, Gregory L. Hansen, Timothy C. David

All Computer Science and Engineering Research

The requirements for the rapid display of radiographic images exceed the capabilities of widely available display, computer and communication technologies. Computed radiography captures data with a resolution of about four megapixels. Large format displays are available that can present over four megapixels. One megapixel displays are practical for use in combination with large format displays and in areas where the viewing task does not require primary diagnosis. This paper describes an electronic radiology system that approximates the highest quality systems, but through the use of several interesting techniques allows the possibility of its widespread installation throughout hospitals. The techniques uses …


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 …


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 …


Simulation And Measurement Of The Radiant Field Produced By Quartz Heating Systems, Travis Lee Turner Jul 1991

Simulation And Measurement Of The Radiant Field Produced By Quartz Heating Systems, Travis Lee Turner

Mechanical & Aerospace Engineering Theses & Dissertations

A method is developed for predicting the radiant heat flux distribution produced by tungsten-filament tubular quartz heating systems with reflectors. The method is an application of Monte Carlo simulation, which takes the form of a ray tracing or random walk scheme. The method is applied to four systems of increasing complexity including; a single unreflected lamp, a single lamp with a flat reflector, a single lamp with a parabolic reflector, and up to six lamps in a six-lamp contoured reflector heating unit. The general methodology of the Monte Carlo method is discussed and applied to the simulation of thermal radiation. …


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 …


The Solution Of A Singular Integral Equation Arising From A Lifting Surface Theory For Rotating Blades, Mark H. Dunn Jul 1991

The Solution Of A Singular Integral Equation Arising From A Lifting Surface Theory For Rotating Blades, Mark H. Dunn

Mathematics & Statistics Theses & Dissertations

A technique is presented for the solution of a linear, two dimensional, singular, Volterra integral equation of the first kind. The integral equation, originally developed by Farassat and Myers, is derived from the basic equations of linearized acoustics and models the lifting force experienced by an infinitesimally thin surface moving tangent to itself. As a particular application, the motion of modern high speed aircraft propellers (Advanced Technology Propellers) is considered. The unknown propeller blade surface pressure distribution is approximated by a piecewise constant function and the integral equation is solved numerically by the method of collocation. Certain simplifying assumptions applied …