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Articles 176581 - 176610 of 197992

Full-Text Articles in Engineering

Construction And Interim Performance Of A Shrinkage Compensating (Class S) Bridge Deck Concrete, Michael D. Stone, David Q. Hunsucker Feb 1994

Construction And Interim Performance Of A Shrinkage Compensating (Class S) Bridge Deck Concrete, Michael D. Stone, David Q. Hunsucker

Kentucky Transportation Center Research Report

Shrinkage Compensating Concrete (Class S) is made with an expansive cement in which the expansion, if restrained, induces compressive stresses that approximately offset tensile stresses induced during drying shrinkage, thereby eliminating or significantly reducing the occurrence of shrinkage cracking in concrete. The objectives of this study were to evaluate the construction and performance of the Shrinkage Compensating Concrete (Class S) and to compare these characteristics to previous Class S concrete data and to conventional Class AA bridge deck concrete. This report summarizes the construction activities and interim performance of experimental decks and barrier walls constructed of shrinkage compensating concrete.


Ccfss News February 1994, Wei-Wen Yu Center For Cold-Formed Steel Structures Feb 1994

Ccfss News February 1994, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Newsletters (1999 - 2008)

No abstract provided.


Numerical Investigation Of Flow Through Wide Angle Diffusers, Moududur Rahman Jan 1994

Numerical Investigation Of Flow Through Wide Angle Diffusers, Moududur Rahman

Dissertations

This study is aimed at the development of a computational technique for the prediction of the flow field in wide angle diffusers. The finite element technique is used for the solution of the governing equations. A commercial software package, NISA/3DFlUID, modified for this specific application was used. The parameters affecting the flow field have been identified. For a wide range of variation of these parameters, the effects on the flow field have been examined. This investigation is an exhaustive and comprehensive numerical study of diffuser flows. Such a study will result in substantial improvement in the understanding of the anatomy …


Aqueous Absorption Of Nitrogen Oxides Induced By Oxychlorine Compounds : A Process Development Study For Flue Gas Treatment, Chen-Lu Yang Jan 1994

Aqueous Absorption Of Nitrogen Oxides Induced By Oxychlorine Compounds : A Process Development Study For Flue Gas Treatment, Chen-Lu Yang

Dissertations

The use of chlorine (Cl2), sodium hypochlorite (NaClO), and sodium chlorite (NaClO2) as oxidizing agents to promote the absorption of nitric oxide (NO) from gas streams has been investigated in the Gas Scrubbing Laboratory of New Jersey Institute of Technology since 1988. The first step of this project had been to screen out the best scrubbing medium for nitric oxide removal from flue gases. The most successful oxidizing agent was found to be sodium chlorite in acidic aqueous solution. The screening results have been accepted for publication in Chemical Engineering Communications. A sodium chlorite containing aqueous …


An Investigation Of The Formation Of Turbulent Water And Abrasive Water Jets, Md. Ekramul Hasan Khan Jan 1994

An Investigation Of The Formation Of Turbulent Water And Abrasive Water Jets, Md. Ekramul Hasan Khan

Dissertations

This study is concerned with the development of a knowledge base for the selection of nozzle geometry by investigating the mechanism of formation and behaviors of water and abrasive water jets. A numerical prediction of turbulent water flow inside various nozzles is developed. The analysis is based on the numerical solution of conservation equations of continuity and momentum as well as equations of turbulent kinetic energy and dissipation for 2-dimensional axisymmetric flow by using a finite element package, FIDAP.

The technique for determining velocities and forces of water jet and abrasive water jet with the Laser Transit Anemometer and Piezoelectric …


Human Visual System Modelling : Analysis Of Evoked Potential Dynamics, Zongqi Hu Jan 1994

Human Visual System Modelling : Analysis Of Evoked Potential Dynamics, Zongqi Hu

Dissertations

The visual evoked potential (VEP) reflects the electrical activity in the cerebral cortex due to visual stimulation. It contains information on signal processing in the visual pathways from the retina, through the lateral geniculate nucleus (LGN) to the cortical level. Although the VEP is generated by various sources in the multi-layer neural network, the functions of some neuronal mechanisms and the transfer characteristics of particular pathways can be revealed and analyzed by use of carefully designed stimuli (Zemon & Ratliff, 1984; Zemon, Victor & Ratliff, 1986). This dissertation focuses on studies of the visual evoked potential as a composite of …


Computer Aided Stress Analysis Of The Femur With Prosthetic Hip Stem Utilizing Computed Tomography, Wei-Chun Chang Jan 1994

Computer Aided Stress Analysis Of The Femur With Prosthetic Hip Stem Utilizing Computed Tomography, Wei-Chun Chang

Dissertations

A computer aided design and analysis method, utilizing computed tomography (CT) is developed, which together with a finite element program determines the stress and deformation patterns in the femur with hip prosthesis. The CT scan data file provides the geometry and the material parameters for the generated finite element model. The three-dimensional finite element model of the femur with hip prosthesis is automatically generated from the CT data file by a preprocessing procedure. The preprocessor includes a CT image display, edge detector, nodes generation, prosthesis simulator, mesh generator and model display. The loading conditions applied on the finite element model …


Design, Construction, And Operation Of Water Treatment Plant Residual Monofills, Haitao Bian Jan 1994

Design, Construction, And Operation Of Water Treatment Plant Residual Monofills, Haitao Bian

Theses

Due to the stringent environmental regulations, landfilling becomes the most viable option for ultimate disposal of water treatment plant (WTP) residues. At present, most states apply the regulations for municipal solid waste (MSW) landfills to the landfilling of WTP residues. This is too stringent since the WTP residues are not hazardous. Therefore, development of suitable criteria for WTP residual monofills is necessary and urgent.

A set of environmental and geotechnical experiments was conducted to characterize WTP residues. It can be concluded that very little leachate will be produced and migration of leachate is unlikely. Also it was noted that insignificant …


Base Plate Placement For A Predefined Workspace Of A Stewart Platform Parallel Manipulator, Rajesh Chanda Jan 1994

Base Plate Placement For A Predefined Workspace Of A Stewart Platform Parallel Manipulator, Rajesh Chanda

Theses

This thesis deals with solving the problem of placing the base plate in an optimum position and orientation in a three dimensional space for the desired locations of the mobile end platform of a Stewart platform parallel manipulator.

First the workspace of the mobile plate is expressed as a function of the base plate position. Then the objective function is generated by summing the squared distances from the various desired locations of the mobile plate to the center of the platform's workspace. This function consists of six unknown variables which define the position and orientation of the base plate. A …


Coordination Of Time-Overcurrent Relays For High-Speed Power Line Protection, Nicos Charalambous Jan 1994

Coordination Of Time-Overcurrent Relays For High-Speed Power Line Protection, Nicos Charalambous

Theses

A properly coordinated protection system is essential to ensure that an electricity distribution network can operate within its requirements, regarding the safety of a power system. Automatic operation is necessary to isolate faults on a power system in a minimum time. The study of time coordination of relays suggests improved ways of power line protection. The protection must be sensitive enough to operate when a fault occurs under minimum fault conditions, yet be stable enough not to operate when its associated equipment is carrying the maximum rated current, which may be a short-time value. A power system is used as …


Patient, Disease And Surgical Parameters In The Prediction Of Histologic Nodes And Recurrence Of Squamous Cell Carcinoma, Adolfo A. Ferreira Jan 1994

Patient, Disease And Surgical Parameters In The Prediction Of Histologic Nodes And Recurrence Of Squamous Cell Carcinoma, Adolfo A. Ferreira

Theses

This research explores the impact of a variety patient, disease and lesion parameters upon the probability of post surgery recurrence of squamous cell carcinoma and the involvement of histologic nodes. It was found that parameters such as number of nodes, Lymph Vascular Space Invasion (LVS), figo stage, growth rate and host response as well as tumor thickness, depth of invasion and lesion size are good predictors. Other parameters such as cell type and condylomas were found to correlate minimally with recurrence and histologic nodes. Surgical parameters such as surgical margin and distance surgical margin were found to have poor correlation …


Three Dimensional Diaphragm Simulation Model For The Relationship Of The Tension, Pressure And Shape, Zhangming He Jan 1994

Three Dimensional Diaphragm Simulation Model For The Relationship Of The Tension, Pressure And Shape, Zhangming He

Theses

Weakness of inspiratory muscles is a major cause of respiratory failure. There are many clinical circumstances in which it may occur. The diaphragm is a major respiratory muscle. It has been difficult to quantify its shape, curvature and length.

To solve this question, a three dimensional diaphragm equation was derived on the, assumption that the diaphragm is only attached at its periphery to the rib cage and the abdomen is filled with fluid. Computer programs were developed to fit the equation to the diaphragm contours obtained from plane X rays.

The results indicate that the ratio of transdiaphragmatic pressure to …


In Vitro Testing And Evaluation Of Intraaortic And Extraaortic Balloon Counterpulsation Devices, Joseph V. Izzo Jan 1994

In Vitro Testing And Evaluation Of Intraaortic And Extraaortic Balloon Counterpulsation Devices, Joseph V. Izzo

Theses

The primary purpose of this project was to develop an in vitro environment in which the intraaortic and extra-aortic balloon pumps could be tested and evaluated. This was done by modifying a mechanical heart simulator -- the pulse duplicator system -- to accommodate both devices, and developing a software system that could collect and process the data relevant to the operation of the two balloons.

Both counterpulsation techniques were tested in the pulse duplicator where the aortic pressure and flow data were collected. The software system then processes the data to calculate all of the parameters affected by counterpulsation.

While …


Fabrication And Characterization Of Wsi2/P-Si And Tasi2/P-Si Devices, Anitha Kodali Jan 1994

Fabrication And Characterization Of Wsi2/P-Si And Tasi2/P-Si Devices, Anitha Kodali

Theses

Thin films Silicides of Tungsten and Tantalum have become very important for IC manufacturing. W and TaSi2 films were deposited on silicon substrates by CVD and Co-sputtering techniques respectively. These films have been characterized using current-voltage technique. The analysis of the obtained experimental measurements has been performed in the light of Schottky-Mott theory. The effects of annealing were studied using Rapid Thermal Processing technique in the temperature range of 500 to 700°C, in nitrogen atmosphere at a constant pressure of 5x10-6 ton for a duration of 30 seconds.The increase in annealing temperature resulted in the formation of ohmic …


The Use Of Cod As An Indicator For Evaluation Of Pretreatment Of Nitrocellulose With Acid Hydrolysis, Han-Chung Lee Jan 1994

The Use Of Cod As An Indicator For Evaluation Of Pretreatment Of Nitrocellulose With Acid Hydrolysis, Han-Chung Lee

Theses

Nitrocellulose is a toxic waste by definition. It is widely used in military and commercial industries. Nitrocellulose fines escaped from the manufacture's process has created problems in receiving water. However, little information is available for the treatment of nitrocellulose. Nitrocellulose is difficult to treat by microorganisms without any pretreatment. Therefore, the main objective of this study is to use acid hydrolysis to break down this material before biological treatment, and find the optimal operation conditions in this process.

In this work, the results indicate that percentage of nitrocellulose decomposing in hydrolysis depends on types of acid, acid concentration, reaction temperature, …


A Graphical Tool For Timed Petri Nets Using Object Oriented Programming, Baopu Liu Jan 1994

A Graphical Tool For Timed Petri Nets Using Object Oriented Programming, Baopu Liu

Theses

The objective of this effort is to develop a computer tool for drawing, editing and simulating Timed Petri Nets using object oriented programming. The developed C++ based Timed Petri Net Simulation Tool, TimedPNT, is capable of simulating discrete systems with both deterministic and stochastic delays. Preselection is used for conflict resolution. Performance and utilization results are automatically collected. XView™ Toolkit is used for building the TimedPNT's interactive graphical interface in compliance with AT&T's OPENLOOK® standard on a SunSparc™ IPX running SunOSTM 4.1.2. Compliance with the X Window standard makes the developed tool portable to other X Window based systems.


Machining Of Silicon Wafers With An Abrasive Water Jet Cutter, Frank J. Marciniak Jan 1994

Machining Of Silicon Wafers With An Abrasive Water Jet Cutter, Frank J. Marciniak

Theses

This thesis consists of a study of the effects of abrasive water jet cutting on brittle silicon substrates. In total, 26 different cuts were made in a single crystal silicon substrate with an abrasive water jet cutter under different conditions of water flow, water pressure, and abrasive flow rate. These cuts were analyzed for surface roughness, and microstructure.

The roughness measurements were compared in order to determine the best possible cutting conditions. The cut with the best roughness of 0.000170 inches was obtained under cutting conditions of 30 KSI water pressure, 1 inch/minute cutting speed, and an abrasive flow rate …


Concurrent Engineering And Design For Manufacture In The Medical Device Industry, Martin A. Mathelier Jan 1994

Concurrent Engineering And Design For Manufacture In The Medical Device Industry, Martin A. Mathelier

Theses

Concurrent Engineering (CE) is an approach to product development in which engineers work on design and manufacturability at the same time. The ultimate goal of concurrent engineering is to reduce the time-to-market while improving quality. This thesis goes into details about the tools necessary to achieve successful product development in the Medical Device Industry. The novelty of this thesis is not in the tools themselves but rather in the way that they are applied to the medical device industry. The need for the CE approach is of utmost importance because of the vast competition in the medical device industry.

The …


Prediction Of Linear And Non-Linear Components Of Cutter Deflection In End Milling Tools, Kimberly Nazimek Jan 1994

Prediction Of Linear And Non-Linear Components Of Cutter Deflection In End Milling Tools, Kimberly Nazimek

Theses

In this study, cutter length, cutter diameter, depth of cut, and magnitude of the instantaneous force vector are examined to determine their effects on cutter deflection during end milling. Their contributions to both linear and non-linear cutter deflection are examined. Models are developed to compute deflection for both flat and ball end mills. These models are evaluated to determine the contribution of each type of deflection encountered during a variety of milling conditions. A discussion on the transfer of deflection data to an estimation of machining accuracy is then presented.


Reconstruction And Enhancement Of Medical Computed Tomography Images, Manoj K. Pattahil Jan 1994

Reconstruction And Enhancement Of Medical Computed Tomography Images, Manoj K. Pattahil

Theses

The aim of Computed Tomography is to obtain information regarding the nature of the materials occupying precise positions inside the body. But due to errors in the projection data, which arise due to errors in measurement, beam hardening, missing data and noise, the reconstructed image has artifacts which reduces its diagnostic value. Thus the image obtained has to be processed to remove these artifacts and to improve the quality of the image. This is achieved by iterative reconstruction along with different post-reconstruction processing. Iterative reconstruction is done by repeating the process of projecting the image and creating new projection data …


A Knowledge-Based Designer Assistant System With Application To The Design Of Helical Springs, Giridhar Raja Jan 1994

A Knowledge-Based Designer Assistant System With Application To The Design Of Helical Springs, Giridhar Raja

Theses

Design problems are generally difficult to solve because the domain of solutions is often infinite (like design of gears, bearings, shafts, springs etc.) and generally requires several iterations before we can arrive at the right solution. The search for the right solution satisfied by several constraints is also time consuming. Thus design intrinsically requires backtracking and several iterations to obtain the desired solution.

In the design of helical springs where the load, deflection, allowable stress, and material are specified, there are an infinite number of solutions. If, in addition to these requirements, the mean coil radius, wire diameter, free height …


Development Of A Non-Intrusive Particle Motion Tracking Technique For Granular Flow Experiments, Jerry R. Volcy Jan 1994

Development Of A Non-Intrusive Particle Motion Tracking Technique For Granular Flow Experiments, Jerry R. Volcy

Theses

Implementation aspects of monitoring the position and orientation of a one-inch diameter particle in space non-intrusively based on the principle of magnetic induction coupling are discussed. A radio-transmitter embedded within the particle induces voltages in receiver antennae. Position and orientation of the particle are deciphered from these voltages. A previously developed math model that predicts the voltage induced in an antenna given the position and orientation of the transmitter with respect to the antenna as well as the numerical techniques used to obtain the inverse solution of computing position and orientation from a given set of voltages are used.

Practical …


Investigation Of Reduced Hypercube (Rh) Networks : Embedding And Routing Capabilities, Michalis A. Sideras Jan 1994

Investigation Of Reduced Hypercube (Rh) Networks : Embedding And Routing Capabilities, Michalis A. Sideras

Theses

The choice of a topology for the interconnection of resources in a distributed-memory parallel computing system is a major design decision. The direct binary hypercube has been widely used for this purpose due to its low diameter and its ability to efficiently emulate other important structures. The aforementioned strong properties of the hypercube come at the cost of high VLSI complexity due to the increase in the number of communication ports and channels per node with an increase in the total number of nodes. The reduced hypercube (RH) topology, which is obtained by a uniform reduction in the number of …


Measurement Of Velocity Of A High Speed Waterjet, Chang-Hsin Yu Jan 1994

Measurement Of Velocity Of A High Speed Waterjet, Chang-Hsin Yu

Theses

In order to maximum the productivity of water jet cutting and cleaning. The determination of the particle velocities at different conditions of water jet formation is essential to the establishment of a prediction model of the cutting results.

The Study is Intended to develop an interface between Laser Transit Anemometer (LTA) and IBM PC for velocity field measurement of the jet by automation of technology design. To achieve this, a turbo basic program is developed to link LTA, counter processor, NIC-320 nicolet oscilloscope and IBM PC together for improve the efficiency and quality of velocity's measurement of the jet.

Because …


Measurement Of Heart Rate Variability Using Correlation Dimension And Entropy, Su Zhang Jan 1994

Measurement Of Heart Rate Variability Using Correlation Dimension And Entropy, Su Zhang

Theses

Heart rate variability regulation is controlled by the autonomic nervous system. Disorders of the autonomic nervous system may cause the loss of heart rate variability. Two new approaches, correlation dimension and entropy, based on ideas from nonlinear dynamics, have been applied to studying heart rate variability. The correlation dimension measures the extent of correlation between the data points. The entropy measures the amount of information needed to specify the state of a system. The interbeat interval signal (1BI) from eighteen subjects (nine normal controls and nine patients with Chronic Fatigue Syndrome (CFS) ) have been analyzed and compared. The results …


Semi-Automated Approach To Shape Optimal Design Of Planar Structures, Gurinder Pal Singh Jan 1994

Semi-Automated Approach To Shape Optimal Design Of Planar Structures, Gurinder Pal Singh

Theses

This paper presents a general algorithm, using IDEAS programmability features to integrate different phases of shape optimization process. The present work is mainly concentrated on planar structures, defined by thin or shell finite elements. Interactive programs are generated to convert input data to geometric models, to define mesh areas, to generate finite element mesh and to execute adaptive mesh refinement techniques. The importance of automated mesh generation and refinement is highlighted and various optimization methods are considered. Further, a special attention is given to integration issues of shape optimization capabilities into CAD environment. To demonstrate the developed algorithm, an automotive …


Contour Extraction From Hvem Image Of Microvessel Using Active Contour Models, Manping Xiao Jan 1994

Contour Extraction From Hvem Image Of Microvessel Using Active Contour Models, Manping Xiao

Theses

This thesis reports the research results on automatic contour extraction from high voltage electron microscope (HVEM) image of thick cross section montages of small blood vessels. The previous work on this subject, which was based on the conventional edge detection operations combined with edge linking, has proven inadequate to describe the inner structural compartments of microvessels. In this thesis, an active contour model (commonly referred to as "Snakes") has been applied to advance the previous work. Active contour models have proven themselves to be a powerful and flexible paradigm for many problems in image understanding, especially in contour extraction from …


Analysis For Handling Flexible Green Sheets With Automated Tools, Chao Xie Jan 1994

Analysis For Handling Flexible Green Sheets With Automated Tools, Chao Xie

Theses

The electronics industry is characterized by rapid technological advances. Increase in number of I/O interconnections on chips and need for more compact assemblies is forcing designer to consider multilayer ceramic packaging. With the advancement in co-fired technology, the green tapes are becoming widely used now, and will be even more so in the future. There is considerable knowledge and expertise on the preparation of multilayer ceramic materials but little information is available on the handling of laminate ceramic green sheets with automated tools.

In this thesis, we will analyze the displacement, the principal and shearing stress of the different sized …


Design And Implementation Of Fuzzy Logic Controller For A Process Control Application, Sujit S. Nerurkar Jan 1994

Design And Implementation Of Fuzzy Logic Controller For A Process Control Application, Sujit S. Nerurkar

Theses

Many industrial applications of fuzzy logic control have been reported. This thesis studies and reports the problems associated with the Heat-exchanger temperature control via conventional PID control implemented with Programmable Logic Controllers (PLC) and provides an example of design and implementation of fuzzy logic controllers (FLC's) for a Heat exchanger in a Water for Injection (WFI) system.

After a basic FLC was designed and tested, it is shown how its rule base evolved to achieve superior performance by utilizing additional low-cost sensing information in the process and its environment. A method for the implementation of FLC's into the existing PLC …


Sulfuric Acid Resistance Of Fly Ash Mortar, Walairat Bumrongjaroen Jan 1994

Sulfuric Acid Resistance Of Fly Ash Mortar, Walairat Bumrongjaroen

Theses

Crown corrosion of concrete pipe and its subsequent repair is a topic much discussed in recent years. Present protective methods have not worked effectively. Due to its properties and its low cost, fly ash was used as a cement replacement of mortar to investigate its sulfuric acid resistance.

Different types and different percentages of fly ashes were mixed with and without admixtures including microsilica, and superplasticizer. The main parameters investigated included the chemical compounds, the fineness and the volume of fly ash. 2"x2" cubes were immersed in a 10% sulfuric acid pond. The weight of each cube was determined continuously …