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Articles 178411 - 178440 of 197988

Full-Text Articles in Engineering

Behavior Of High Strength Concrete And Slender Reinforced Concrete Columns With And Without Steel Fibers, Lin Showmay Hsu Oct 1992

Behavior Of High Strength Concrete And Slender Reinforced Concrete Columns With And Without Steel Fibers, Lin Showmay Hsu

Dissertations

A series of compression tests are conducted on 3 in. by 6 in. cylindrical specimens using a modified testing method that give the complete stress-strain behavior for both plain and fibrous high strength concretes with or without tie confinements. The volume fractions of fiber in the concrete are 0%, 0.5%, 0.75%, and 1.0%, respectively. Empirical equations are proposed herein to represent the complete stress-strain relationships of high strength and high strength fibrous concretes with compressive strength exceeding 10,000 psi. Various parameters are studied and their relationships are experimentally determined. The comparison between the experimental and analytical results shows to have …


Fabrication And Characterization Of Gated Silicon Field Emission Micro Triodes, Nanchou Liu Oct 1992

Fabrication And Characterization Of Gated Silicon Field Emission Micro Triodes, Nanchou Liu

Dissertations

This dissertation describes the fabrication technology and characterization of a gated silicon field emission micro triode that is a novel electron tunneling device for generating electron emission into a vacuum. Conic (point) and wedge field emitter structures with nm-scale radii were fabricated in silicon and GaAs by etching, MOCVD and dry oxidation. A new self-aligned process was developed for fabrication of vertical field emission triodes. This process allows control of gate opening to less than 0.5 μm diameter without the need of electron-beam writing. It also provides a planar gate electrode and a thick dielectric layer for reduction of the …


The Influence Of Pore Fluids On Shear Strength And Stress-Strain Behavior Of Granular Soils, Prasanna Ratnaweera Oct 1992

The Influence Of Pore Fluids On Shear Strength And Stress-Strain Behavior Of Granular Soils, Prasanna Ratnaweera

Dissertations

When a dry granular soil is subjected to an external load, the stresses are transferred through mineral to mineral contacts. The shear strength of such a soil is governed by its contact properties. Presence of a thin layer of fluid between mineral to mineral contacts in a saturated soil will alter its contact properties. Therefore any change in the physical properties of pore fluid can logically be reasoned to influence the deformation characteristics of granular soils.

To investigate the influence of pore fluid viscosity on shear strength and stress-strain behavior of a soil, a series of consolidated drained triaxial tests …


Expert System For The Injection Molding Of Engineering Thermoplastics, Tzy-Cherng Jan Oct 1992

Expert System For The Injection Molding Of Engineering Thermoplastics, Tzy-Cherng Jan

Dissertations

Injection molding of engineering thermoplastics is the most widely used manufacturing method in industry. It is a priority to maintain a deviation-free operating environment to ensure high quality, low cost manufacture. An expert system for the injection molding of engineering thermoplastics has been investigated. The system can be used to attenuate the deviations experienced during the injection molding of engineering thermoplastics. The system is coded in C programming language.

The resolution procedures of this system include two stages such as the definition of declarative knowledge and the procedure of corrective actions. In the definition of declarative knowledge, all of the …


A Study On Radical Scavenging And Magnetic Resonance Imaging Characteristics Of Stable Radical Nitroxides, Shiey-Shiun Horng Oct 1992

A Study On Radical Scavenging And Magnetic Resonance Imaging Characteristics Of Stable Radical Nitroxides, Shiey-Shiun Horng

Dissertations

Several nitroxides have been prepared for study of their image enhancement capability. These nitroxides contain different nitroxyl moieties within one molecule. On MRI examination for the nitroxides prepared, TEMPO and HPTPO are better due to their better water solubility, even though some of the others have more nitroxyl centers available. The intensity response is linear with respect to concentration in the range studied in most of the cases except for HPTPO, whose intensity finally reaches maximum when its concentration is higher than 10 mM.

Three sources of biomass, namely, liver microsomes, whole-cell yeast and a bacterial activated sludge consortium, have …


Design For Manufacturability And Assembly, Srinivas Mullapudi Oct 1992

Design For Manufacturability And Assembly, Srinivas Mullapudi

Theses

This report presents a study of the various concepts of design for manufacturability and assembly with some case studies, and examples.

The goal of DFM is reduction of parts and simplifying assembly process. A simple faucet has been studied and attempts have been made at re-designing the same using the techniques of design for manufaturability as postulated by Boothroyd, Dewhurst and Henry Stoll.


Development Of The Interface Between Cad And Waterjet Nc Systems, Sivayasivan Sambandan Oct 1992

Development Of The Interface Between Cad And Waterjet Nc Systems, Sivayasivan Sambandan

Theses

There has been a continuous need in the present to develop softwares that provide interface between cutting machines and computer control. There involves a number of complex stages from the birth of an algorithm, to develop such software, till the end where it successfully gets tested and implemented. Cutting Path Simulation (CPS) is a partially developed software designed to model 2-d and 3-d objects and down load them to water jet cutting machine. Additional menus were created in the software to perform specific functions. Bugs that existed in the previously done work were removed. Investigation was conducted on the feasibility …


The Design And Manufacture Of Institutional Trays Using Simultaneous Engineering, Antonio Schmidt Oct 1992

The Design And Manufacture Of Institutional Trays Using Simultaneous Engineering, Antonio Schmidt

Theses

This study evaluates thermoformed trays as used in the food service industry. The resin used in fabricating trays is a blend of Acrylonitrile Butadiene Styrene (ABS) and Polycarbonate (PC). The life of the trays is presently between 1 to 3 years. The trays are used in correctional facilities and hospitals. The handling of the tray is not abusive. The trays are pulled out of service once they exhibit stress cracking.

To further understand the unpredictable life of the thermoformed trays an understanding of the behavior of the plastics is required and the method of comparing one resin from another, as …


Computation Of Collision Parameters Of Spheres By Computer Vision, Sumit Sen Oct 1992

Computation Of Collision Parameters Of Spheres By Computer Vision, Sumit Sen

Theses

Collision parameter evaluation of rigid spherical particles requires estimation of pre- and post-impact position, velocity and angular velocity vectors of colliding particles. A three dimensional experimental technique is devised where the instantaneous position and orientation of the particles are determined by analyzing frames obtained through high speed video imaging system. Since the image obtained is two dimensional, a mirror setting is designed to capture two orthogonal views of collision in order to estimate motion in depth. The translational velocity vector is determined from the position information extracted through application of available image analysis techniques over two time frames of digitized …


Three-Dimensional Beam-Columns, Mohammad Hassan Shams Oct 1992

Three-Dimensional Beam-Columns, Mohammad Hassan Shams

Theses

This thesis explores several special cases of three-dimensional beam-columns and suggests that the method of finite differences can be used when a solution of general case is required. The thesis begins with a review of the three-dimensional beam-column equations and then shows how these equations can be used to generate the member stiffness matrix for the nonlinear analysis of three-dimensional frames. Examples are included which discuss the differences between the analytical and numerical solutions.


Application Of Desktop Manufacturing System (Sla) For The Manufacturing Of A Centrifugal Pump Impeller Using Cad (I-Deas), Wasimuddin Azam Muhammad Syed Oct 1992

Application Of Desktop Manufacturing System (Sla) For The Manufacturing Of A Centrifugal Pump Impeller Using Cad (I-Deas), Wasimuddin Azam Muhammad Syed

Theses

Desktop Manufacturing (DTM) systems which combine personal computer, laser and other technologies are being used to sculpt objects from computer generated models created on computer aided design (CAD) workstations. As a member of DTM systems, StereoLithography Apparatus (SLA) transforms 3-dimensional designs into a 3-D output. This can substantially reduce the time required to produce a prototype through the process of photopolymerization. The process involves the transfer of a liquid plastic monomer into a solid polymer by exposing it to ultraviolet light.

Although the process looks productive, inefficiencies can occur, if incorrect parameters are selected before its application for a particular …


Modeling, Evaluation, And Control Of A Flexible Manufacturing Cell Using Petri Nets, Glenn Arthur Thorniley Oct 1992

Modeling, Evaluation, And Control Of A Flexible Manufacturing Cell Using Petri Nets, Glenn Arthur Thorniley

Theses

This thesis describes the usefulness of Petri nets in modeling, evaluating, and controlling a Flexible Manufacturing Cell (FMC). The basics of Petri net theory are explained and a specific FMC is examined. First, the FMC is modeled. The purpose of modeling is to facilitate the evaluation and provide a framework on which the control methodologies can be applied. The objective of the evaluation is to determine how the FMC would benefit most by replacing or adding equipment. Several ideas on control are combined to form a useful framework for the designing of the control net. With this framework the control …


Bragg Reflection Grating Waveguide, Wei Zhong Oct 1992

Bragg Reflection Grating Waveguide, Wei Zhong

Theses

Bragg reflection waveguides (BRW) are non-conventional optical guides in which optical confinement is achieved via periodic set of grooves or stratified media along the guiding path. BRW may also serve as optical filters, because of spectral discrimination of the guiding process. A novel UV laser ablation technique was used in this thesis to fabricate periodic metal-clad polymeric waveguides. Spin-on technique was applied to fabricate the waveguide core on glass substrates, evaporation of metal film and selective ablation process defined the optical guides. Various periodicities have been fabricated and the near field patterns have been measured to compare the different guiding …


Planning Of Optimal Transit System Design, Yongning Liu Oct 1992

Planning Of Optimal Transit System Design, Yongning Liu

Theses

This study presents a methodological approach for finding an optimal design of bus transit service in an urban transportation corridor with elastic demand and under various objective functions. Service design decision variables to be optimized include the route length, route density, headway, number of stops and stop spacing pattern. The objective functions that optimize the transit system design include: minimizing operator cost, maximizing profit, minimizing sum of operator and user costs and maximizing the users' net benefits.

The analysis uses an elastic demand function wherein the number of trips are sensitive to the quality of service provided and price charged …


Removal Of Volatile Organic Compounds (Voc's) Acetone And Ethyl Alcohol Emitted In The Manufacture Of A Multi-Base Propellant, Yih-Leu Liu Oct 1992

Removal Of Volatile Organic Compounds (Voc's) Acetone And Ethyl Alcohol Emitted In The Manufacture Of A Multi-Base Propellant, Yih-Leu Liu

Theses

The Production Base Modernization Activity located at Picatinny Arsenal, initiated this study for the removal of the low concentrations of VOC's, acetone and ethyl alcohol emitted from the mixer operation and the forced air dry unit in the manufacture of a multi -base propellant. Air pollution requirements necessitate 85 % removal of the VOC's prior to discharge of the vent gases into the atmosphere. Because of the availability of sulfuric acid, it is proposed to use 70 percent or stronger acid as the absorbing agent in a recirculating acid absorption tower.

Vapor - Liquid Equilibrium ( VLE ) data were …


Mineralization Of 2-Chlorophenol Using A Hollow Fiber Ultrafiltration System In Combination With A Reactor Containing An Immobilized White Rot Fungus, Sheau-Ming Tung Oct 1992

Mineralization Of 2-Chlorophenol Using A Hollow Fiber Ultrafiltration System In Combination With A Reactor Containing An Immobilized White Rot Fungus, Sheau-Ming Tung

Theses

Phanerochaete chrysosporium, a white rot fungus was immobilized on a packed-bed reactor, and was used to mineralize an aqueous stream contaminated with 50 ppm of 2-chlorophenol. Hollow fiber ultrafiltration membranes (for 5,000 daltons and 10,000 daltons molecular weight cut-oft) were utilized to retain the extracellular enzyme resulting from the immobilized fungus in a recirculation loop outside of the reactor.

It was found here that the concentration of proteins (roughly proportional to the extracellular enzyme releasd by the fungus) does not correlate with the rate of degradation of 2-chlorophenol in the system. The protein was concentrated 1.5 fold in the recycle …


Adaptive Map Configuration And Dynamic Routing To Optimize The Performance Of A Satellite Communication Network, Santhalingam Balasekar Oct 1992

Adaptive Map Configuration And Dynamic Routing To Optimize The Performance Of A Satellite Communication Network, Santhalingam Balasekar

Theses

Availability of alternate routes are shown to enhance the performance of non-hierarchical circuit switched networks at moderate load conditions on which the networks typically operate. But alternate routes introduce instability at heavy and overloaded conditions and at these load conditions the network performance is found to deteriorate. To alleviate this problem, one of the control mechanism used is to reserve a fraction of the capacity of each link for direct routed calls. In this work, the feasibility of changing the facilities of a satellite network is taken advantage in optimizing the performance of such a network. A mesh connected, circuit …


Automatic Motion Analysis Of Colliding Spheres, John Vijayakumar Caesar Oct 1992

Automatic Motion Analysis Of Colliding Spheres, John Vijayakumar Caesar

Theses

Motion analysis is useful to compute linear and angular velocities and acceleration of an object from a sequence of images. This thesis is part of an investigation to compute the translation and rotation velocities needed to determine the collision parameters of two colliding spheres. This involves the tracking of the spheres and feature points on the spheres over a time interval. An experimental setup releases two spheres such that they collide and a high speed imaging system, i.e., Kodak Ektapro 1000 is utilised to record the motion of the spheres. The imaging system is capable of recording at a speed …


Point Pattern Matching By Heuristic Methods : A Genetic Algorithm And Simulated Annealing, Erh-Chin Chen Oct 1992

Point Pattern Matching By Heuristic Methods : A Genetic Algorithm And Simulated Annealing, Erh-Chin Chen

Theses

The problem we consider is to find a subset of points in a pattern that best match to a subset of points in another pattern through a transformation in an optimal sense. Exhaustive search to find the best assignment mapping one set of points to another set is, if the number of points that are to be matched is large, computationally expensive. We propose two stochastic searching techniques - a genetic algorithm and simulated annealing to search for the best ("almost the best") assignment efficiently. To make the comparison between GA and SA fair, we introduce a piece-wise linear cooling …


Uses And Applications Of Artificial Intelligence In Manufacturing, Manojkumar H. Desai Oct 1992

Uses And Applications Of Artificial Intelligence In Manufacturing, Manojkumar H. Desai

Theses

The purpose of the THESIS is to provide engineers and personnels with a overview of the concepts that underline Artificial Intelligence and Expert Systems. Artificial Intelligence is concerned with the developments of theories and techniques required to provide a computational engine with the abilities to perceive, think and act, in an intelligent manner in a complex environment.

Expert system is branch of Artificial Intelligence where the methods of reasoning emulate those of human experts. Artificial Intelligence derives it's power from its ability to represent complex forms of knowledge, some of it common sense, heuristic and symbolic, and the ability to …


The Collapse Of The Cypress Viaduct During The Loma Prieta Earthquake Of October 17, 1989, Mohamed M. Eid Oct 1992

The Collapse Of The Cypress Viaduct During The Loma Prieta Earthquake Of October 17, 1989, Mohamed M. Eid

Theses

The Loma Prieta earthquake of October 17, 1989 in California was one of the most disastrous earthquakes in U.S history. It caused damage to commercial, residential, and industrial structures, transportation and utilities.

This study includes investigations about the Cypress Viaduct collapse re?ported by:

  1. California Governor's Board of Inquiry [4].
  2. National Institute of Standards and Technology (NEL) W.
  3. 3The Author.

Investigators in the first report concluded that the collapse was due to horizontal ground motion. In the second one, it was due to the vertical ground motion.

In the author's investigation, a detailed static and dynamic analyses are performed to determine …


Cost Deployment Based On Quality Function Deployment, John Goceljak Oct 1992

Cost Deployment Based On Quality Function Deployment, John Goceljak

Theses

A methodology for Cost Deployment based on Quality Function Deployment (QFD) architecture is developed and explained. Following a comprehensive review of Quality Function Deployment terminology and composition, a house-of-quality is developed, and matrix correlation methodologies are discussed. Current applications are presented to illustrate the scope and adaptability of this quality assurance tool. In addition, an exercise in product design and review is conducted to illustrate a unique approach to cost deployment. Quality Function Deployment issues, including software, consulting, and preferred practices are also presented.


The Acoustic Properties Of Human Femoral Bone, Mark Lacianca Oct 1992

The Acoustic Properties Of Human Femoral Bone, Mark Lacianca

Theses

Over the last decade, interest has grown in the use of the scanning acoustic microscope (SAM), with a single lens being used for both transmitting and receiving the acoustic signal. A major objective of this thesis was to determine if the transmission and ultrasonic techniques yield similar "quantitative" results, when measuring the elastic constants of human femoral bone. The transmission technique has been used since 1970 to yield values for the elastic properties of calcified tissue. Previously the SAM has been used as a qualitative tool, where an acoustic impedance map is produced. This map can show areas of bone …


Shop Floor Planning And Control In Integrated Manufacturing Systems, Tahir Mahmood Oct 1992

Shop Floor Planning And Control In Integrated Manufacturing Systems, Tahir Mahmood

Theses

The implementation of a shop floor planning and control system is a prerequisite in establishing an effective computer integrated manufacturing system. A shop floor control system integrates management production goals with the capabilities and limitations of the manufacturing plant. Shop floor planning begins with a long term rough cut capacity plan and evolves into near term, capacity requirements and input/output plans. Shop floor control provides a status of in-process operations and a measure of the plants success in executing the plan. Effective use of technology on shop floor increases the efficiency of the manufacturing plant. Simulation is an important tools …


Posterior Stabilized Knee Design Biomechanical Considerations, Donald E. Mcnulty Oct 1992

Posterior Stabilized Knee Design Biomechanical Considerations, Donald E. Mcnulty

Theses

Numerous posterior stabilized knee systems are available for primary and revision total knee arthroplasty. Design of these systems requires an understanding of the articulating geometries and kinematic/kinetic biomechanical considerations of the normal knee. The findings for the normal knee are integrated into the design of a prosthetic system.

The natural femoral, tibial and patella articulating geometries are defined to enable subsequent kinematic and kinetic analyses. The articulating geometries are characterized from review of anthropometric studies of the tibiofemoral and patellofemoral joint.

The kinematic analysis of the natural knee defines knee motion in terms of rotation, adduction/abduction, range of motion and …


A Study Of Annular Slurry Jet For Abrasive Waterjet Cutting, Thomas Kuriakose Oct 1992

A Study Of Annular Slurry Jet For Abrasive Waterjet Cutting, Thomas Kuriakose

Theses

The objective of this project is to study the performance of an annualr slurry jet nozzle for abrasive waterjet cutting. This nozzle has been invented by Avraham. Harnoy, Department of Mechanical Engineering, NJIT and presented to the patent committee of NJIT in May 1990. This study includes design and development of prototyes and testing of their performance. Moreover, it includes initial theoretical study of the flow behavior.

The idea is based on the merging of a high velocity pure waterjet with an annular jet of a slurry of water and abrasives at low velocity. The two jets merge outside the …


Design For Productivity Using Gd&T, Srihari G. Acharya Oct 1992

Design For Productivity Using Gd&T, Srihari G. Acharya

Theses

No abstract provided.


Errors In Constant-Velocity Shaft Couplings, Philip M. Remington Oct 1992

Errors In Constant-Velocity Shaft Couplings, Philip M. Remington

Theses

A Multiloop spatial system of rotations is used to represent a shaft coupling, allowing a transmission plane which may deviate from the plane of symmetry to be specified. The plane of transmission, for intersecting input and output shaft axes, is the locus of intersections of screw axes that compose the system. By prescribing the transmission plane outside of the plane of symmetry (commonly called the "homokinetic plane" or "bisecting plane") to pecified orientations, a phase shift between the input and output shaft rotational displacements will he quantified. The rotational phase shift between the input and output shafts can be evaluated …


Quantitative Assessment Of Myocardial Oxygen Supply And Demand Using A Dynamic Model Of The Cardiovascular System, Badrinath R. Puranic Oct 1992

Quantitative Assessment Of Myocardial Oxygen Supply And Demand Using A Dynamic Model Of The Cardiovascular System, Badrinath R. Puranic

Theses

A quantitative understanding of the changes in coronary, pulmonary and systemic hemodynamic variables and their effect on myocardial supply and demand is important to the better management of anesthetic care of patients with impaired cardiac function. Animal studies have identified those hemodynamic factors that play an important role in determining the balance between oxygen supply and demand for the myocardium. These include myocardial contractility, left ventricular end-diastolic volume, systemic arterial pressure, systemic vascular resistance, and heart rate. The interactions of these factors are complex and their combined effects on myocardial oxygen supply and demand are difficult to predict a priori. …


Automatic Surface Mount Solder Joints Inspection, Zhu Liu Oct 1992

Automatic Surface Mount Solder Joints Inspection, Zhu Liu

Theses

This thesis reports the research results on automatic inspection of solder joints on printed circuit boards. The previous work on this subject has been advanced significantly in the following three aspects. With the support of AT&T Bell Lab, the most updated surface mount solder joints are inspected in this work instead of larger simulation solder joints or traditional through hole solder joints in the previous work. A small set of features is extracted for surface mount solder joints in both infrared and visual light inspection. A new image processing software named Khoros has been applied to improve the quality of …