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2000

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Articles 1 - 30 of 1185

Full-Text Articles in Engineering

Initial Hertzian Characteristics Of The Human Tooth As A Damage Tolerant Bio-Ceramic/Bio-Composite Bi-Layer, Ivory Camille Kilpatrick Dec 2000

Initial Hertzian Characteristics Of The Human Tooth As A Damage Tolerant Bio-Ceramic/Bio-Composite Bi-Layer, Ivory Camille Kilpatrick

Theses

The objective of this thesis was to investigate the Hertzian Contact response of human teeth and how the response behavior is related to that of model ceramic bi-layers (high modulus brittle ceramics on compliant substrates). Hertzian Contact is a blunt indentation method, which uses a hard spherical indenter to apply a normal compressive load. Clinical variables of masticatory (occlusal) force and cuspal curvature identify closely with the independent Hertzian variables of contact load and sphere radius [1]. This method offers insight into the role of microstructure and microstructure- sensitive mechanical properties. It was hypothesized that tooth damage modes and patterns ...


Oczyszczanie Gazów Odlotowych Ze Spalania Odpadów Niebezpiecznych, Robert Oleniacz Dec 2000

Oczyszczanie Gazów Odlotowych Ze Spalania Odpadów Niebezpiecznych, Robert Oleniacz

Robert Oleniacz

Flue gas cleaning system is a very important part of each hazardous waste incineration plant. Air pollutant emission limit values permissible for this process in Member States of the European Union are so rigorous that the installation designers there are forced to use very effective and of course expensive solutions. In the paper a review of methods and systems used to the treatment of flue gases from hazardous waste incineration is presented. This can be particularly useful in the face of the adaptation of existing waste incineration plant operating in Poland with European Union requirements.

English title: Cleaning of flue ...


Numerical Studies Of Newtonian And Viscoelastic Fluids, Felix J. Alcocer Dec 2000

Numerical Studies Of Newtonian And Viscoelastic Fluids, Felix J. Alcocer

Dissertations

The direct numerical simulation (DNS) approach is used to understand the flow behavior of Newtonian and viscoelastic fluids in porous materials, four-to-one contraction and the flow of a Newtonian fluid past an airfoil.

In simulations the viscoelastic fluid is modeled by the finitely extensible nonlinear elastic (FENE) dumbbell and Oldroyd-B models. The finite element method (FEM) is used to discretize the flow domain. The DNS results show that the permeability of a periodic porous medium depends on the wavelength used for arranging particles in the direction of flow. Specifically, it is shown that for a given particle size and porosity ...


Electro-Magnetic Control Of Cylinder Wake, Zhihua Chen Dec 2000

Electro-Magnetic Control Of Cylinder Wake, Zhihua Chen

Dissertations

The objective of this dissertation is to develop open and closed-loop control algorithms for manipulating wake flows past a solid cylinder in an electrically low-conducting fluid (e.g. seawater). The intent is to avoid both vortex shedding and flow separation from the body. It is desired to reduce the mean drag significantly and prevent the lift from becoming non-zero at all times. This is achieved through the introduction of a Lorentz force in the azimuthal direction generated by an array of permanent magnets and electrodes located on the solid structure. The array of actuators offers the advantage of making the ...


Kinematic Synthesis Of Adjustable Spatial Four And Five-Bar Mechanisms For Finite And Multiply Separated Positions, Kevin Russell Dec 2000

Kinematic Synthesis Of Adjustable Spatial Four And Five-Bar Mechanisms For Finite And Multiply Separated Positions, Kevin Russell

Dissertations

Although spatial mechanisms are more general in structure than planar mechanisms, their applications are few due to the limited number of practical design tools and the complexity of those available. It is in fact the task of the future to develop effective, but practical design tools for spatial mechanisms.

This research presents several new methods for synthesizing adjustable spatial mechanisms. The first method involves the kinematic synthesis of spatial mechanisms for multiphase motion generation. Using this method, spatial four and five-bar mechanisms can be synthesized to achieve different phases of prescribed rigid body positions. The theory of this approach has ...


Analysis And Control Of Monolithic Piezoelectric Nano-Actuator, Xuemei Sun Dec 2000

Analysis And Control Of Monolithic Piezoelectric Nano-Actuator, Xuemei Sun

Dissertations

The study of the monolithic piezoelectric actuator, the dominant type of micropositioner is an attractive and challenging area, where realtime control theory and digital signal processing are effectively applied. The actuator can be applied in precision instruments and precision control, such as microscopes, medical and optics instruments because of the piezoelectric ceramic's high resolution, fast transient response, and potential low cost. However, hysteresis nonlinearity and lightly damped vibration exist in the system, which limit the actuator applications.

This work focuses on the hysteresis characteristics in time and frequency domains along with experimental and simulated results to verify the effectiveness ...


Numerical Modeling And Optimization Of Waterjet Based Surface Decontamination, Konstantin Babets Dec 2000

Numerical Modeling And Optimization Of Waterjet Based Surface Decontamination, Konstantin Babets

Dissertations

The mission of this study is to investigate the high-pressure waterjet based surface decontamination. Our specific objective is to develop a practical procedure for selection of process conditions at given constraints and available knowledge. This investigation is expected to improve information processing in the course of material decontamination and assist in the implementation of the waterjet decontamination technology into practice. The development of a realistic procedure for processing of a chaotic and non-accurate information constitutes the main accomplishment of this study.

The research involved acquisition of representative information about removal of brittle, elastic and viscous deposits. As a result an ...


Interference Suppression And Diversity For Cdma Systems, Xiaodong Cai Dec 2000

Interference Suppression And Diversity For Cdma Systems, Xiaodong Cai

Dissertations

In code-division multiple-access (CDMA) systems, due to non-orthogonality of the spreading codes and multipath channels, the desired signal suffers interference from other users. Signal fading due to multipath propagation is another source of impairment in wireless CDMA systems, often severely impacting performance. In this dissertation, reduced-rank minimum mean square error (MMSE) receiver and reduced-rank minimum variance receiver are investigated to suppress interference; transmit diversity is applied to multicarrier CDMA (MC-CDMA) systems to combat fading; packet combing is studied to provide both interference suppression and diversity for CDMA random access systems.

The reduced-rank MMSE receiver that uses a reduced-rank estimated covariance ...


Empirical Model-Based Control For End Milling Process, Abdelmalak Salib Dec 2000

Empirical Model-Based Control For End Milling Process, Abdelmalak Salib

Dissertations

The main objective of this research is to develop an empirical model-based control mechanism to maintain a fine surface finish quality by maintaining on-line cutting force values. The proposed model has been developed to present the control model constraints, by varying the machining parameters to control the force output to be constant. To relate the surface finish and the cutting force in the end milling machining process, a design of experiment has been conducted to determine the effect of two different materials (aluminium and steel) and the machining parameters (feed rate, spindle speed) at a predefined depth of cut.

Regression ...


Numerical Stimulation Of Stress-Induced Crystallization Of Injection Molded Semicrystalline Thermoplastics, Jianxin Guo Dec 2000

Numerical Stimulation Of Stress-Induced Crystallization Of Injection Molded Semicrystalline Thermoplastics, Jianxin Guo

Dissertations

Injection molded semicrystalline plastic products exhibit variable morphology along their thickness directions. The processing conditions have a significant effect on the crystallinity distribution in the final parts. However, because of the lack of sound theoretical models for stress-induced crystallization kinetics in thermoplastics, simulations of the injection molding process of semicrystalline plastics with the consideration of stress-induced crystallization have been scarce.

A stress-induced crystallization model for semicrystalline plastics is proposed based on the theory that stress induced orientation of polymer chains increase the melting temperature of the plastics, and hence, the supercooling which is the driving force for crystallization. By assuming ...


Assessing The Economic Impact Of Aircraft Noise On Communities, Ithan B. Zimmer Dec 2000

Assessing The Economic Impact Of Aircraft Noise On Communities, Ithan B. Zimmer

Dissertations

The impact of aircraft noise on communities is complex and multi-dimensional. This matter cannot be resolved without careful analysis of a complex array of related problems and issues including the environment, the economy, and quality-of-life concerns of people living in proximity to airports or aircraft routes. The effects of community noise are widespread and varied. Impacts can include sleep and speech interference, activity interference, general annoyance, and property value decrease. In order to improve public policy and provide a foundation for additional research, it is imperative to establish the extent of a problem. Dollars are often the least common denominator ...


Phase-Locked Loop, Delay-Locked Loop, And Linear Decorrelating Detector For Asynchronous Multirate Ds-Cdma System, Sok-Kyu Lee Dec 2000

Phase-Locked Loop, Delay-Locked Loop, And Linear Decorrelating Detector For Asynchronous Multirate Ds-Cdma System, Sok-Kyu Lee

Dissertations

The performance of phase synchronization and code tracking of a digital phase-locked loop (PLL) and delay-locked loop (DLL), respectively, is investigated in wideband asynchronous multirate DS-CDMA system. Dynamic Partial Correlation (DPC) method is proposed to evaluate the autocorrelation and its power spectrum density (PSD) of the cross-correlated terms in the presence of multirate multiple access interference (MMAI) under additive white gaussian noise (AWGN) and fading channel environments. The steady-state probability density function (PDF) and variance of the phase estimator error and code tracking jitter is evaluated by solving the first-order Fokker-Planck equation.

Among many linear multiuser detectors which decouple the ...


Deposition Of Tantalum On Steel By Sputtering, Bhavin Shah Dec 2000

Deposition Of Tantalum On Steel By Sputtering, Bhavin Shah

Theses

Recent interest in tantalum deposition comes from two different applications. One is in microelectronics where thin tantalum films (< 1 µm) are used as diffusion barrier layers for copper interconnects. The other involves its application as a material for corrosion and wear resistant coating on surfaces that are subjected to high stresses and harsh chemical and erosive environments.

This thesis is a part of the investigation done at the Ion Beam and Thin Film Research Laboratory at NJIT to study the deposition conditions and properties of tantalum thin films. It includes the design and construction of Planar D.C. Magnetron Sputtering System and Cylindrical D.C. Magnetron Sputtering System for deposition on the planar and cylindrical surfaces of steel, respectively. The electrical characteristics of the cylindrical system were tested in a range of pressures and conditions for initiation and maintaining ...


An Automated Approach For Comparative Analysis Of Interval And Heart Rate Variability, Taral Oza Dec 2000

An Automated Approach For Comparative Analysis Of Interval And Heart Rate Variability, Taral Oza

Theses

Cardiovascular disease is the primary cause of death in the adult population. Half of these cardiac deaths occur as sudden death. Some of the parameters from the surface ECG recording (a noninvasive technique) carry important information and have special significance in research, as they are good indicators of diseases leading to heart attacks, sudden cardiac death and other similar cardiac problems. Measurement of QT interval variability and heart rate variability are two such parameters, which has received much attention of researchers.

An algorithm has been developed to measure and compare the two significant parameters, the QT interval variability and the ...


Highway Advisory Radio In The State Of New Jersey, Thomas Mark Nemeth Dec 2000

Highway Advisory Radio In The State Of New Jersey, Thomas Mark Nemeth

Theses

Highway Advisory Radio (HAR) is a broadcasting system used by transportation agencies to disseminate vital real-time traffic information to motorists. Each transmitter is restricted by the rules and regulations of the Federal Communications Commission (FCC) to an average broadcast radius of three to five miles. Most commonly these transmitters are located at major highway intersections, such that motorists may take alternate routes in case of congestion or emergencies.

All operational HAR transmitters in New Jersey were identified and their coverage zones were quantitatively characterized in terms of the signal to noise ratio at the receiver. These experimental results were then ...


Resource Allocation For Cdma Downlink To Achieve Maximum Throughput, Anil Bircan Dec 2000

Resource Allocation For Cdma Downlink To Achieve Maximum Throughput, Anil Bircan

Dissertations

Growing interest in cellular phones, wireless modems, instant messaging, pagers with the increasing use of the Internet in daily life indicate that wireless high speed Internet access and wireless multimedia applications are in great demand. The barrier to satisfy this demand is the provision of sufficiently high bit rates in severe wireless mobile channel conditions, for a multitude of services, each requiring different and perhaps even time-varying quality of services (QoS) that can be more demanding than the QoS required by today's voice service. New generation systems will enable provision of a multitude of services each with different QoS ...


Video Indexing And Summarization Using Motion Activity, Kadir Askin Peker Dec 2000

Video Indexing And Summarization Using Motion Activity, Kadir Askin Peker

Dissertations

In this dissertation, video-indexing techniques using low-level motion activity characteristics and their application to video summarization are presented. The MPEG-7 motion activity feature is defined as the subjective level of activity or motion in a video segment. First, a novel psychophysical and analytical framework for automatic measurement of motion activity in compliance with its subjective perception is developed. A psychophysically sound subjective ground truth for motion activity and a test-set of video clips is constructed for this purpose. A number of low-level, compressed domain motion vector based, known and novel descriptors are then described. It is shown that these descriptors ...


Nonlinear Optical Properties Of Nano Structures, Mahesh U. Ajgaonkar Dec 2000

Nonlinear Optical Properties Of Nano Structures, Mahesh U. Ajgaonkar

Dissertations

Nonlinear optical properties of nanoscale semiconductors had been a topic of intense research in recent years in attempts to realize all-optical communication systems. These semiconductor nanoclusters, in the range of 1-100nm are hosted in a dielectric material and are considered as a particular example of Conditional Artificial Dielectric (CAD). It has been reported that the dielectric properties of such materials will be greatly changed by light intensity.

Two main paths to realize nano semiconductor clusters are reported in this dissertation. The Pulsed Laser Deposition (PLD) technique is first described. Here we were investigating the effect of surface modification of nano ...


Object Detection And Activity Recognition In Digital Image And Video Libraries, Ibrahim Burak Ozer Dec 2000

Object Detection And Activity Recognition In Digital Image And Video Libraries, Ibrahim Burak Ozer

Dissertations

This thesis is a comprehensive study of object-based image and video retrieval, specifically for car and human detection and activity recognition purposes. The thesis focuses on the problem of connecting low level features to high level semantics by developing relational object and activity presentations. With the rapid growth of multimedia information in forms of digital image and video libraries, there is an increasing need for intelligent database management tools. The traditional text based query systems based on manual annotation process are impractical for today's large libraries requiring an efficient information retrieval system. For this purpose, a hierarchical information retrieval ...


An Efficient Expression Of The Timestamp And Period In Packet-And Cell-Based Schedulers, Dong Wei Dec 2000

An Efficient Expression Of The Timestamp And Period In Packet-And Cell-Based Schedulers, Dong Wei

Theses

Scheduling algorithms are implemented in hardware in high-speed switches to provide Quality-of-Service guarantees in both cell-based and packet-based networks. Being able to guarantee end-to-delay and fairness, timestamp-based fair queuing algorithms, which include SCFQ, WFQ, WF2Q and WF2Q+, have received much attention in the past few years. In timestamp-based fair queuing algorithms, the size of timestamp and period determines the supportable rates in terms of the range and accuracy. Furthermore, it also determines the scheduler's memory in terms of offchip bandwidth and storage space. An efficient expression can reduce the size of the timestamp and period without compromising the accuracy ...


Development And Application Of A Computer Simulation Tool For Ecological Risk Assessments, Haiyi Lu Dec 2000

Development And Application Of A Computer Simulation Tool For Ecological Risk Assessments, Haiyi Lu

Theses

In an effort to improve tools in ecological risk assessment (ERA), an ERA software tool was developed and applied. Based on a preliminary evaluation of existing ecorisk models, the relative deficiencies were identified and included the need for a user-friendly interface, an interactive database management system (DBMS), and a comprehensive evaluation of exposure pathways. In this research, Visual Basic (VB) 6.0 and Microsoft SQL server were selected for developing the Windows-based interface and local DBMS, respectively. For the exposure estimate, Yuma and Aberdeen Proving Grounds were identified as baseline ecosystems. Terrestrial and aquatic plant and animal receptor selection was ...


Testing Of Semiconductor-Based Adsorption Modified Photosensitive (Samp) Sensor For Response To Toluene, Ashish Agrawal Dec 2000

Testing Of Semiconductor-Based Adsorption Modified Photosensitive (Samp) Sensor For Response To Toluene, Ashish Agrawal

Theses

The response of semiconductor-based adsorption modified photosensitive sensor is based on the dye-enhanced photoconductivity of a CdS semiconducting film. The change in this photoconductivity is brought about when organic molecules are sorbed onto the dye-coated surface. The response is related to the overlap in the infrared spectrum of the dye with that of the analyte.

This research was carried out to study the response of the sensor to a typical hydrocarbon, toluene. The sensor was tested for its response to concentrations of toluene ranging from 2.6 ppm to 200 PPM in nitrogen. The sensor was tested under non-flow conditions ...


Optimization Of Nitrogen Removal In Sequencing Batch Reactor, Suppakit Poonyachat Dec 2000

Optimization Of Nitrogen Removal In Sequencing Batch Reactor, Suppakit Poonyachat

Theses

Operating parameters for sequencing batch reactor have the influenceon each substrate concentration. Concentration profile changes as operationparameters are changed. The study was conducted to model the variationin effluent concentration from sequencing batch reactor. MLVSS and cycletime are the parameters that were varied. Concentration in Fill, React,and Settle Period were calculated by using kinetic equations.

The results can show that these parameters have effects on the concentrationprofile. The increase of MLVSS can lower the concentration of BOD andammonium concentration in React period. Increasing MLVSS can show thatmore substrate utilization and nitrification process occur more rapidly.Concentration of nitrate at the ...


Reactive Media For Chromium Reduction Under Alkaline Conditions For Use In Permeable Reactive Barriers, Sachin V. Apte Dec 2000

Reactive Media For Chromium Reduction Under Alkaline Conditions For Use In Permeable Reactive Barriers, Sachin V. Apte

Theses

The purpose of this study was to select the appropriate reactive media for chromate reduction to treat groundwater (high pH) with permeable reactive barriers. The study addresses groundwater contamination for three chromium refining sites located in Hudson County, New Jersey. The use of iron (Fe0) as a reactive medium was studied and found to be insufficient for use in permeable reactive barriers because of the high pH conditions of groundwater at these sites. Pyrite and iron (Fe0)-pyrite mixtures were studied as viable reactive media by considering their passivation kinetics, reductive capacities and solubility properties.

Column experiments were ...


Emulation Of The Dataflow Computing Paradigm Using Field Programmable Gate Arrays (Fpgas), Segreen Ingersoll Dec 2000

Emulation Of The Dataflow Computing Paradigm Using Field Programmable Gate Arrays (Fpgas), Segreen Ingersoll

Theses

Building a perfect dataflow computer has been an endeavor of many computer engineers. Ideally, it is a perfect parallel machine with zero overheads, but implementing one has been anything but perfect. While the sequential nature of control flow machines makes them relatively easy to implement, dataflow machines have to address a number of issues that are easily solved in the realm of control flow paradigm. Past implementations of dataflow computers have addressed these issues, such as conditional and reentrant program structures, along with the flow of data, at the processor level, i.e. each processor in the design would handle ...


A Study And Some Experimental Work Of Digital Image And Video Watermarking, Tsui-Feng Liu Dec 2000

A Study And Some Experimental Work Of Digital Image And Video Watermarking, Tsui-Feng Liu

Theses

The rapid growth of digitized media and the emergence of digital networks have created a pressing need for copyright protection and anonymous communications schemes. Digital watermarking (or data hiding in a more general term) is a kind of steganography technique by adding information into a digital data stream. Several most important watermarking schemes applied to multilevel and binary still images and digital videos were studied. They include schemes based on DCT (Discrete Cosine Transform), DWT (Discrete Wavelet Transform), and fractal transforms. The question whether these invisible watermarking techniques can resolve the issue of rightful ownership of intellectual properties was discussed ...


The Electrostatic Interaction Of Charged, Dust-Particle Pairs In Plasmas, M. E. Markes, P. F. Williams Dec 2000

The Electrostatic Interaction Of Charged, Dust-Particle Pairs In Plasmas, M. E. Markes, P. F. Williams

Faculty Publications from the Department of Electrical and Computer Engineering

We report the results of a study of the electrostatic interaction between negatively charged particles in a plasma. The goal of the study was to investigate the possibility of an attractive interaction which would make possible the formation of “molecules” of particles. For all approximations relating the positive ion density to the local electrostatic potential that we examined, we find that the interaction is repulsive for all particle separations.


A Simulation-Based Heuristic For Fleet Assignment, Sonia Rosario Anorga Dec 2000

A Simulation-Based Heuristic For Fleet Assignment, Sonia Rosario Anorga

FIU Electronic Theses and Dissertations

Integer programming, simulation, and rules of thumb have been integrated to develop a simulation-based heuristic for short-term assignment of fleet in the car rental industry. It generates a plan for car movements, and a set of booking limits to produce high revenue for a given planning horizon.

Three different scenarios were used to validate the heuristic. The heuristic's mean revenue was significant higher than the historical ones, in all three scenarios. Time to run the heuristic for each experiment was within the time limits of three hours set for the decision making process even though it is not fully ...


Chemical And Dynamical Speciation Of Mobile Ions In The Glassy Fast Ionic Conductor Ag2s+B2s3+Sis2: A 109ag Nuclear Magnetic Resonance Study, Tomoko Akai, Steve W. Martin, Ferdinando Borsa Dec 2000

Chemical And Dynamical Speciation Of Mobile Ions In The Glassy Fast Ionic Conductor Ag2s+B2s3+Sis2: A 109ag Nuclear Magnetic Resonance Study, Tomoko Akai, Steve W. Martin, Ferdinando Borsa

Materials Science and Engineering Publications

109Ag NMR in the highly conductive glass 0.525Ag2S+0.475(0.5B2S3+0.5SiS2) was investigated from 230 to 433 K. The 109Ag NMR spectra reveal for the first time three well resolved lines corresponding to three kinds of chemically speciated Ag ions in sites with different chemical shifts in a macroscopically homogeneous glass. This chemical speciation of Ag ions is discussed in relation to the microstructure of the glass. As the temperature is increased, the three lines that originate from three different species of ions are narrowed, but these lines exist independently up to 433 K, the highest ...


Evaluation Of Kentucky's Graduated Driver Licensing System, Kenneth R. Agent, Jerry G. Pigman, Lorena C. Steenbergen, Susan H. Pollack, Pamela S. Kidd, Caroline Mccoy Dec 2000

Evaluation Of Kentucky's Graduated Driver Licensing System, Kenneth R. Agent, Jerry G. Pigman, Lorena C. Steenbergen, Susan H. Pollack, Pamela S. Kidd, Caroline Mccoy

Kentucky Transportation Center Research Report

Kentucky's current GDL program, which applies to drivers up to age 18, was enacted in 1996. The program includes a six-month instruction permit for drivers under age 18 (minimum age 16), a restriction on driving between midnight and 6am and a requirement for adult-supervised driving for permit drivers. In addition, there is a six-point limit on traffic violations with a penalty of license suspension for drivers under age 18, a requirement for a four-hour driving safety education class (or driver education course) and a 0.02 ml/dl limit on blood alcohol concentration (continues up to age 21 ).

Objectives ...