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1991

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Articles 1 - 30 of 1045

Full-Text Articles in Engineering

Behavior Of Square And L-Shaped Slender Reinforced Concrete Columns Under Combined Biaxial Bending And Axial Compression, Wen Hu Tsao Dec 1991

Behavior Of Square And L-Shaped Slender Reinforced Concrete Columns Under Combined Biaxial Bending And Axial Compression, Wen Hu Tsao

Dissertations

A numerical analysis was developed to evaluate the complete load-deflection and moment-curvature relationships for square and L-shaped slender reinforced concrete columns subjected to biaxial bending and axial load. This computer model can be used for any cross section geometry and material properties of normal concrete. The analysis was based on a deformation control and both the ascending and descending branches of curves can be studied. The finite difference method was introduced to calculate the deflections which satisfy the compatibility equations. Six square slender columns and eight L-shaped slender columns were tested to compare their experimental load-deformation results with the analytical ...


Error Detection And Correction In Compressed Data, Nadir Sezgin Dec 1991

Error Detection And Correction In Compressed Data, Nadir Sezgin

Theses

Encoded data is very sensitive to the channel errors. Especially if the data is compressed by Arithmetic Encoding procedure, then the error propagation is very high. The error propagation in Arithmetic Coding is studied. Exploiting the high error propagation property when compressing data by Arithmetic encoding procedure, two different algorithms have been proposed for error detection and correction. Under certain conditions these algorithms detect and with a very high probability correct the errors introduced to the compressed data.


Software Development For Analysis Of Stochastic Petri Nets Using Transfer Functions, Aman U. Jamwal Dec 1991

Software Development For Analysis Of Stochastic Petri Nets Using Transfer Functions, Aman U. Jamwal

Theses

This thesis research is an implementation of a closed-form analytical technique for study, evaluation and analysis of Stochastic Petri Nets (SPN). The technique is based on a theorem that an isomorphism exists between an SPN and a Markov Chain. The procedure comprises five main steps: reachability graph generation of the underlying Petri net, transformation of the reachability graph to a state machine Petri net, calculation of transfer functions, computation of equivalent transfer functions via Mason's rule, and computation of performance parameters of the SPN model from the equivalent transfer functions and their derivatives. The software is developed in UNIX ...


Analytical Methodology For Atm Control Panel Design, Donald C. Johnson Dec 1991

Analytical Methodology For Atm Control Panel Design, Donald C. Johnson

Theses

This thesis presents a methodology for control panel design and layout along with a case study of an automated teller machine (ATM). A predictive model of human endurance and fatigue is developed from anthropometric, biomechanical and kinematics research. The layout problem is formulated to assign controls to locations to minimize the fatigue imposed on an operator performing a known set of tasks. A family of optimal and near-optimal layouts are found using conventional algorithms. The final hardware design refinements are suggested by human factors concerns. Ergonomic guidelines are also proposed for software aspects of the design. The methods and guidelines ...


Conditional Artificial Dielectrics ; Fabry-Perot Etalon, Ling-Yi Hu Dec 1991

Conditional Artificial Dielectrics ; Fabry-Perot Etalon, Ling-Yi Hu

Theses

Fabry-Perot etalons are optical resonators comprise of two mirrors and a spacer layer. By embedding a thin, photo-sensitive layer ( Conditional Artificial Dielectric - CAD layer ) in the middle of the spacer layer, we were able to photo-control the transmission properties of a Fabry-Perot etalon. Different structures have been analyzed and measured to find that a change of .01 was photo-activated in the refractive index of the Conditional Artificial Dielectric layer.


Improving The Throughput Of Plasticating Extruders : Manufacture Of Non-Circular Pellets, Measurement Of Their Interparticulate Friction Coefficient, And Implications For Screw Design, Chia-Ying Liu Dec 1991

Improving The Throughput Of Plasticating Extruders : Manufacture Of Non-Circular Pellets, Measurement Of Their Interparticulate Friction Coefficient, And Implications For Screw Design, Chia-Ying Liu

Dissertations

This dissertation addresses the hypothesis that the interparticulate friction coefficient of a bed of polymeric particulates is a function of the cross-section of the pellets. Most pellets have a circular cross-section especially those that are strand cut. But when such pellets constitute a particulate bed there are few restrictions to adjacent pellets turning with respect to each other, or of the beds rupturing under shear load. This rupture can occur in plasticating extrusion, and it results in a poorly mixed melt with an inhomogeneous temperature distribution. The temperature fluctuations cause viscosity fluctuations which in turn cause pressure fluctuations. The pressure ...


Redesign Of Parts And Simulation Of Flexible Assembly Cell For Safety Water Shower Assembly, Balraj Y. Gardilla Dec 1991

Redesign Of Parts And Simulation Of Flexible Assembly Cell For Safety Water Shower Assembly, Balraj Y. Gardilla

Theses

A Design for Assembly (DSA) method is used to analyze the safety water shower assembly and to redesign the components with emphasis on meeting the criteria of allowing for flexible Assembly Cell (FAS). An Expert System is developed to select the right Assembly using VP-Expert. This thesis contrasts the old and new safety water shower assembly designs and describes the design of a final Flexible Assembly Cell. A PUMA 550 robot was investigated for use in the cell design. The flexible Assembly cell is simulated on silicon graphics using the IGRIP software. The economics of each part presentation method is ...


High Frequency Oscillator Comprising Cointegrated Thin Film Resonator And Active Device, Robert J. Weber, Stanley G. Burns, Steven D. Braymen Dec 1991

High Frequency Oscillator Comprising Cointegrated Thin Film Resonator And Active Device, Robert J. Weber, Stanley G. Burns, Steven D. Braymen

Iowa State University Patents

A cointegrated high frequency oscillator including a thin film resonator and activedevices formed on the same semiconductor substrate and by a process which is compatible with formation of both the thin film resonator and the active devices. The processes utilized in formation of the thin film resonator are adapted to microelectronic processing techniques such that the steps of formation of the active devices and the thin film resonator can be intermixed to the degree necessary to allow, for example, the metallization layers to serve as elements both of the active devices and the thin film resonator.


Comparison Of Timing Jitter In External And Monolithic Cavity Mode-Locked Semiconductor Lasers, Dennis J. Derickson, P. A. Morton, J. E. Bowers, R. L. Thornton Dec 1991

Comparison Of Timing Jitter In External And Monolithic Cavity Mode-Locked Semiconductor Lasers, Dennis J. Derickson, P. A. Morton, J. E. Bowers, R. L. Thornton

Electrical Engineering

A comprehensive timing jitter comparison is made for mode-locked semiconductor lasers using active, passive, and hybrid mode-locking techniques in both external and monolithic cavity configurations. Active mode locking gives the lowest residual rms timing jitter of 65 fs (150 Hz-50 MHz), followed by the hybrid and passive mode-locking techniques. It is found that monolithic cavity devices with all active waveguides have higher timing jitter levels than the comparable external cavity case.


A Multiple Coupled Microstrip Transmission Line Model For High-Speed Vlsi Interconnect Simulation, Lawrence Stevan Uzelac Dec 1991

A Multiple Coupled Microstrip Transmission Line Model For High-Speed Vlsi Interconnect Simulation, Lawrence Stevan Uzelac

Dissertations and Theses

A model is presented which incorporates the advantages of a mixed mode simulation to characterize transmission line behavior in multiple coupled Transmission line systems. The model is intended for use by digital circuit designers who wish to be able to obtain accurate transmission line behavior for complex digital systems for which continuous time simulation tools such as SPICE would time prohibitive. The model uses a transverse electromagnetic wave approximation to obtain solutions to the basic transmission line equations. A modal analysis technique is used to solve for the attenuation and propagation constants for the transmission lines. Modal analysis done in ...


Variable Rate Fertilization- Can The Technology Pay For Itself?, Michael Schmitt, Dean Fairchild Dec 1991

Variable Rate Fertilization- Can The Technology Pay For Itself?, Michael Schmitt, Dean Fairchild

Proceedings of the Integrated Crop Management Conference

Soils form a continuum across every farmer's field, constantly changing in both physical and chemical characteristics. Sometimes these changes are visible; sometimes they are completely masked to the eye. Variables such as organic matter, water-holding capacity, pH, and soil nutrient levels differ; combined, they affect crop yields. In either case, these differences should result in different management practices, including fertilizer applications, being recommended for different soils within a field.


"The Right Stuff", Farming By Location, Tom Colvin, Jack Ambuel, Kandiah Jeyapalan Dec 1991

"The Right Stuff", Farming By Location, Tom Colvin, Jack Ambuel, Kandiah Jeyapalan

Proceedings of the Integrated Crop Management Conference

A satellite-based positioning system is being developed to determine the location of farm equipment while working in the field. A satellite receiver mounted in a moving tractor or combine calculates position coordinates based on signals received from a selection of satellites in the Department of Defense Global Positioning System (GPS). The position coordinates are retrieved from the receiver by a computer and combined in a common data base with additional information collected by the computer such as yield, soil fertility, soil moisture, temperature, implement draft, and fuel consumption. There are a number of possible applications for this system. One is ...


Prescription Farming Based On Soil Property Sensors, Larry D. Gaultney Dec 1991

Prescription Farming Based On Soil Property Sensors, Larry D. Gaultney

Proceedings of the Integrated Crop Management Conference

Prescription farming as used in the context of this paper will be defined thusly: The site specific management of variable cropping inputs so as to achieve maximal economic return while minimizing degradation of the environment. Obviously many factors must be integrated into a management plan to achieve such a worthwhile goal. Proper equipment, skills, management ability, and timing are all crucially important. Perhaps the most important factor, and the one which is the most limiting currently, is the ability to collect and organize detailed information about the site in question.


Lavarty Elevator, Inc. Complete Calibration Service Program, Michael L. White Dec 1991

Lavarty Elevator, Inc. Complete Calibration Service Program, Michael L. White

Proceedings of the Integrated Crop Management Conference

The business of selling and servicing crop protection chemicals and fertilizers is becoming very technical and complex. Luckily, we have trained the people in this business well. Odds are that within every dealership we have open in Iowa, there is at least one competent professional who can help our farmer customer. At a drop of the hat, this individual can begin quoting economic thresholds, rates per acre, cost per acre, depth of incorporation, harvest intervals, adjuvant combinations, etc. We have the knowledge to recommend the correct product, but who insures the correct application? The process is complete if applied by ...


Japan-U.S. Seminar On Polymer Synthesis, Otto Vogl, Hiroyuki Nishide Dec 1991

Japan-U.S. Seminar On Polymer Synthesis, Otto Vogl, Hiroyuki Nishide

Otto Vogl

No abstract provided.


Illustrative Examples Based On The Asce Standard Specification For The Design Of Cold-Formed Stainless Steel Structural Members, Shin-Hua Lin, Wei-Wen Yu, Theodore V. Galambos Dec 1991

Illustrative Examples Based On The Asce Standard Specification For The Design Of Cold-Formed Stainless Steel Structural Members, Shin-Hua Lin, Wei-Wen Yu, Theodore V. Galambos

Center for Cold-Formed Steel Structures Library

PREFACE During the past four years, two methods were developed for the design of stainless steel structural members at the University of Missouri-Rolla with consultation of Professor T. V. Galambos at the University of Minnesota. One of the methods is based on the load and resistance factor design (LRFD) and the other is based on the allowable stress design (ASD). Both design methods are now included in the new ASCE Standard 8-90, Specification for the Design of Cold-Formed Stainless Steel Structural Members. At the September 21, 1990 meeting of the Control Group of the ASCE Stainless Steel Cold-Formed Section Standards ...


Computerized Aircraft Accident Investigation: Federal Aviation Administration Aviation Safety Inspectors' Perceptions, David S. Ryan Dec 1991

Computerized Aircraft Accident Investigation: Federal Aviation Administration Aviation Safety Inspectors' Perceptions, David S. Ryan

Theses - Daytona Beach

The purpose of this study was to solicit the perceptions of Federal Aviation Administration (FAA) Aviation Safety Inspectors (ASIs) on the use of a personal computer in the aircraft accident investigation process. A descriptive study survey questionnaire was used to collect the data for the study, which was sent to 150 FAA ASIs. The data collected supported the hypothesis that aircraft accident investigators think the use of a computer will help them with accident report form completion, managing the accident data collected, and in determining the factors contributing to an accident. Furthermore, the data supported the hypothesis that the use ...


An Investigation Of The Floor Attachment Assembly Of A Large Transport Aircraft Seat Subjected To Crash Dynamic Loadings, Mark William Creager Dec 1991

An Investigation Of The Floor Attachment Assembly Of A Large Transport Aircraft Seat Subjected To Crash Dynamic Loadings, Mark William Creager

Theses - Daytona Beach

Accident investigations by the National Transportation Safety Board concluded that the passenger seat and restraint systems found in today's aircraft used by the airlines are inadequate to protect the occupant in airplane crashes. Computer models were developed of the seat-track assembly and finite element analyses were performed subjected to crash dynamic loadings. The seat-track interface was modeled with gap elements to accurately model the geometric interaction between the track and seat-track fittings. Results showed large deformations and stresses above yielding in both the seat and track when subjected to accelerations prescribed for certification under the Federal Aviation Administration (FAA ...


Polymer Research In Austria. I: Introduction And The Facilities, Otto Vogl, Josef Schurz, Bernd Thrattnigg, Klaus Hummel, Wolfgang Daimler, Klaus Lederer Dec 1991

Polymer Research In Austria. I: Introduction And The Facilities, Otto Vogl, Josef Schurz, Bernd Thrattnigg, Klaus Hummel, Wolfgang Daimler, Klaus Lederer

Emeritus Faculty Author Gallery

No abstract provided.


Japan-U.S. Seminar On Polymer Synthesis, Otto Vogl, Hiroyuki Nishide Dec 1991

Japan-U.S. Seminar On Polymer Synthesis, Otto Vogl, Hiroyuki Nishide

Emeritus Faculty Author Gallery

No abstract provided.


Polymer Research In Austria. I: Introduction And The Facilities, Otto Vogl, Josef Schurz, Bernd Thrattnigg, Klaus Hummel, Wolfgang Daimler, Klaus Lederer Dec 1991

Polymer Research In Austria. I: Introduction And The Facilities, Otto Vogl, Josef Schurz, Bernd Thrattnigg, Klaus Hummel, Wolfgang Daimler, Klaus Lederer

Otto Vogl

No abstract provided.


Resource Integration Using A Large Knowledge Base In Carnot, Christine Collet, Michael N. Huhns, Wei-Min Shen Dec 1991

Resource Integration Using A Large Knowledge Base In Carnot, Christine Collet, Michael N. Huhns, Wei-Min Shen

Faculty Publications

A method for integrating separately developed information resources that overcomes incompatibilities in syntax and semantics and permits the resources to be accessed and modified coherently is described. The method provides logical connectivity among the information resources via a semantic service layer that automates the maintenance of data integrity and provides an approximation of global data integration across systems. This layer is a fundamental part of the Carnot architecture, which provides tools for interoperability across global enterprises.


Material Handling In A Flexible Manufacturing Systems Processing Part Families, Paul Savory, Gerald Mackulak, Jeff Cochran Dec 1991

Material Handling In A Flexible Manufacturing Systems Processing Part Families, Paul Savory, Gerald Mackulak, Jeff Cochran

Industrial and Management Systems Engineering Faculty Publications

The objective of this simulation study is to analyze the system performance of a six machine flexible manufacturing system cell in which a material handling system is to be incorporated. The analysis focuses on determining the production potential of the cell by grouping common parts into "families". To accomplish this, computer simulation models are developed using the SIMAN simulation language.

Initially the manufacturing cell is modeled with no material handling system to get an upper bound estimate of production output. We next explore the impact that an automatic guided vehicle (AGV) has on system performance of the manufacturing system cell ...


Evaluation Of Torsional Provisions In Seismic Codes, Anil K. Chopra, Rakesh K. Goel Dec 1991

Evaluation Of Torsional Provisions In Seismic Codes, Anil K. Chopra, Rakesh K. Goel

Civil and Environmental Engineering

The effects of plan asymmetry on the earthquake response of code-designed, one-story systems are identified with the objective of evaluating how well these effects are represented by torsional provisions in building codes. The earthquake-induced deformations and ductility demands on resisting elements of asymmetric-plan systems, designed according to several different codes, are compared with their values if the system plan were symmetric. The presented results demonstrate that the design eccentricity in building codes should be modified in order to achieve the desirable goal of similar ductility demands on asymmetric-plan and symmetric-plan systems. The design eccentricity should be defined differently for elastic ...


Unsteady Flow In Vertical, Converging Tubes, Hamid Johari, William W. Durgin Dec 1991

Unsteady Flow In Vertical, Converging Tubes, Hamid Johari, William W. Durgin

Office of the Provost and Vice President of Academic Affairs Scholarship

The discharge of liquids from vertical tubes with various contraction geometries was studied via the unsteady Bernoulli equation. The temporal variations of the exit velocity and fluid level in the tube were found from the numerical integration of nonlinear differential equations. Sudden, quadratic, and exponential contraction geometries were considered. For inlet to exit area ratios greater than two, the flow initially accelerates to a maximum speed and then it decelerates for the geometries studied. The exponential contraction has the shortest discharge time. The solutions also reveal that the largest possible velocity and the shortest discharge time are achieved in a ...


Acuta Enews December 1991, Vol. 20, No. 12 Dec 1991

Acuta Enews December 1991, Vol. 20, No. 12

ACUTA Newsletters

In This Issue

10-XXX gives occasion for fraud

President's Message

YaleNET, a variety of services

Think ahead to prevent fraud

MOREnet links 12 campuses

Positions available


Investigations Of The Mechanical Behavior Of Graphite/Peek (Apc-2) Composits, Kyun Lee Dec 1991

Investigations Of The Mechanical Behavior Of Graphite/Peek (Apc-2) Composits, Kyun Lee

Doctoral Dissertations

The purpose of this research is to investigate the effects of two phenomena that are specific to thermoplastic resin composites. The phenomena are:

(a) the significant nonlinear creep, that occurs especially at high temperatures, which affects the residual thermal stresses in a geometrically constrained structure.

(b) the spatially nonuniform transverse crystallinity which develops in some fiber-reinforced thermoplastic composites, which introduces spatial variability and nonlinearity in the stiffness of the composite.

The first part of the dissertation is related to the former phenomenon. It presents a computational scheme for the optimal temperature path for APC-2 composite laminate, modeled as nonlinear, thermorheologically ...


Construction Evaluation Of Hydraway Edge Drains And Outlet Pipes On Interstate 64, L. John Fleckenstein, David L. Allen Dec 1991

Construction Evaluation Of Hydraway Edge Drains And Outlet Pipes On Interstate 64, L. John Fleckenstein, David L. Allen

Kentucky Transportation Center Research Report

This report documents the installation of the Hydraway edge drain (version two) on 1-64 in Franklin·Woodford-Scott and Fayette Counties. The edge drain was placed on the back side of the trench against the shoulder and backfilled with a sand/slurry.

From observations on this project and several previous projects, the sand/slurry backfill helps to insure the integrity of the drainage system during initial backfilling. It is apparent that the sand slurry backfill provides a better installation in comparison to previous methods using excavated trench material. Notable trench settlement did occur on this project. It is apparent that insufficient ...


Ultrasonic Nde Of Thick Composites, R. Bruce Thompson, Donald O. Thompson, David K. Holger, David K. Hsu, M. S. Hughes, Emmanuel P. Papadakis, Yu-Min Tsai, Loren W. Zachary Dec 1991

Ultrasonic Nde Of Thick Composites, R. Bruce Thompson, Donald O. Thompson, David K. Holger, David K. Hsu, M. S. Hughes, Emmanuel P. Papadakis, Yu-Min Tsai, Loren W. Zachary

Aerospace Engineering Conference Papers, Presentations and Posters

A series of ultrasonic techniques being developed for the characterization of thick composites are described. Techniques for the in-situ measurements of elastic constants on thick-walled cylinders based on the times of a variety of ultrasonic modes of propagation are first presented, followed by discussion of the determination of the porosity from measurements of the frequency dependence of the attenuation. Two techniques for imaging delamination are then discussed. The first involves inferring size from plots of reflected signal amplitude versus lateral position of the transducer with a model for beam propagation in anisotropic media used to deconvolve the effects of the ...


An Experimental And Analytical Investigation On The Production Of Microfibers Using A Single Hole Melt Blowing Process, Bryan David Haynes Dec 1991

An Experimental And Analytical Investigation On The Production Of Microfibers Using A Single Hole Melt Blowing Process, Bryan David Haynes

Doctoral Dissertations

An extensive experimental investigation was undertaken to study the influence of the processing variables on the production of microfibers using a single hole melt blowing process. included: The processing variables that were investigated air jet exit velocity, polymer throughput, die air gap, die setback, polymer and air temperatures, polymer melt viscosity as expressed by ASTM Melt Flow Rate (MFR), and collection distance. Polypropylene was used for the investigation. In addition to the experimental investigation, a one dimensional single hole melt blowing analytical model was developed.

The air jet exit velocity and polymer throughput had the most influence on the average ...