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Theses/Dissertations

1994

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Articles 1 - 30 of 407

Full-Text Articles in Engineering

Effects Of Ergonomic Worksite Changes On Risks For Cumulative Trauma Disorders Of The Upper Body In An Assembly And Press Operation Job, David B. Mahone Dec 1994

Effects Of Ergonomic Worksite Changes On Risks For Cumulative Trauma Disorders Of The Upper Body In An Assembly And Press Operation Job, David B. Mahone

Theses

Cumulative trauma of the upper body is associated with a variety of individual and job factors. An effort to optimize the human-hardware interface to minimize cumulative trauma is favored. Workers in a set of jobs had complained about hand/wrist and shoulder discomfort. One job was selected for testing alternate machine controls and worksite layout. Electromyography was used to test muscle activity, and photogoniometry was used to measure posture.

For the group of ten worker-subjects, statistically significant decreases in hand/wrist and shoulder muscle activity were found. A marginal, but significant increase in neck muscle activity was also found. When ...


Experimental And Numerical Determination Of Fluid Velocity Profiles And Turbulence Intensity In Mixing Vessels, Chun-Chiao Chou Dec 1994

Experimental And Numerical Determination Of Fluid Velocity Profiles And Turbulence Intensity In Mixing Vessels, Chun-Chiao Chou

Dissertations

In this study, both a laser-Doppler velocimeter (LDV) and a computational fluid dynamic (CFD) software package (FL UENI) were used to experimentally determine and numerically predict the velocity distribution of an unbaffled and a baffled mixing vessel. Two types of impellers were employed, namely a flat blade turbine (FBT) and a pitched blade turbine (PBT). These impellers were studied in a single-impeller or multiple-impeller configuration in the unbaffled and baffled vessels. The flow characteristics in the impeller regions were measured by LDV and used as boundary conditions in the numerical computation. Turbulence effects were numerically simulated using either the k-c ...


Low Pressure Chemical Vapor Deposition Of Copper Films From Cu(I)(Hfac)(Tmvs), Wei-Shang King Dec 1994

Low Pressure Chemical Vapor Deposition Of Copper Films From Cu(I)(Hfac)(Tmvs), Wei-Shang King

Theses

Recently, copper has been found as a possible substitute for Al alloys because of its low resistivity (1.67 μΩ • cm) and potentially improved resistance to electromigration. Conventional physical vapor deposition (PVD) method do not provide the conformal deposition profile for the high density integrated circuit, therefore, chemical vapor deposition (CVD) has become the most promising method for the resulting conformal profile.

In this work, a cold wall, single wafer, CVD tungsten reactor was used for the deposition of copper with Cu(I)(hfac)(tmvs). Film growth rates were between 100 to 800 A/min depending on processing conditions, and ...


A Comparison Between Revealed Preference (Rp) And Stated Preference (Sp) Based On Results Of Simulations, Qiuzi Chen Dec 1994

A Comparison Between Revealed Preference (Rp) And Stated Preference (Sp) Based On Results Of Simulations, Qiuzi Chen

Theses

This research quantifies the potential biases resulted from two different data generation methods used in transportation modeling: Revealed Preference (RP) and Stated Preference (SP) techniques. Revealed Preference technique is the conventional approach to generate data. It relies on observed or reported data of actual behavior. Stated preference technique is a new data generation method. It creates transportation scenarios using hypothetical data. Conventional studies favor the use of revealed reference. However, full description of advantages and weaknesses of using revealed preference technique is not available in literature, neither point-to-point comparison between stated preference and revealed preference techniques. This research contributes to ...


Scheduling Of Flexible Manufacturing Systems With Automated Guided Vehicles Using Petri Net Models, Hua-Sheng Chiu Dec 1994

Scheduling Of Flexible Manufacturing Systems With Automated Guided Vehicles Using Petri Net Models, Hua-Sheng Chiu

Theses

In this thesis, Petri net models for Flexible Manufacturing Systems (EMS) are constructed. A firing sequence of the Petri net from the initial marking to the final marking can be seen as a schedule of the modeled FMS. By using the branch-and-bound algorithm, an optimal schedule of the FMS can be obtained.

Automated Guided Vehicle Systems (AGVS) are increasingly used for material handling in factories and warehouses. An AGVS can reduce labor costs and is ready to be integrated into an automated factory. This thesis presents two AGVS models (shared and duty) which integrate the control of AGVS with the ...


A Three Stage Large Dynamic Range Automatic Transimpedance Control Amplifier, Karim Joseph Sikias Dec 1994

A Three Stage Large Dynamic Range Automatic Transimpedance Control Amplifier, Karim Joseph Sikias

Theses

Long haul fiber optic communication systems require extremely sensitive, low noise amplification of the weak photo diode currents generated by the received light power. Two types of amplifiers have been used for this application: a high input impedance integrating amplifier/differentiating equalizer combination or a transimpedance amplifier. Optical receivers designed with integrating amplifiers exhibit severe low frequency drift and overload problems and are not generally used in wide dynamic range receiver design. This thesis will describe an extremely wide dynamic range transimpedance amplifier incorporating unique methods to maintain stability, wide bandwidth low pulse width distortion during overload conditions.


Development Of An Expert System To Facilitate A Pump Manufacturing/Warehouse Facility, Muhammad Mutahir Ghauri Dec 1994

Development Of An Expert System To Facilitate A Pump Manufacturing/Warehouse Facility, Muhammad Mutahir Ghauri

Theses

The objective of this study is to evaluate the effectiveness of utilizing an expert system technology as it relates to manufacturing. It appears that our industries are still uncertain about this technology. In the first phase of this study, procedure for deployment of this technology is discussed. Secondly a knowledge-based expert system is developed, using a VP-Expert microcomputer shell. The system is made of three modules, inventory module, cost analysis module, and decision making module (for the selection of pumps).

A warehouse was selected for the analysis, which carries the finished product in the form of pumps. The quantities and ...


The Mobile Satellite Service (Mss) Systems For Global Personal Communications, Kiho Lee Dec 1994

The Mobile Satellite Service (Mss) Systems For Global Personal Communications, Kiho Lee

Theses

A worldwide interest has arisen on personal communications via satellite systems. The recently proposed mobile satellite service(MSS) systems are categorized four areas: geostationary earth orbit(GEO) systems, medium earth orbit(MEO) systems, low earth orbit(LEO) systems, and highly elliptical orbit(HEO) systems. Most of the systems in each category are introduced and explained including some technical details. The communication links and orbital constellations of some systems are analyzed and compared with different categories, and with different systems. Some economical aspects of the systems are mentioned. The regulatory issues about frequency spectrum allocation, and the current technical trends in ...


A Petri-Net Based Methodology For Modeling, Simulation, And Control Of Flexible Manufacturing Systems, Venkatesh Kurapati Dec 1994

A Petri-Net Based Methodology For Modeling, Simulation, And Control Of Flexible Manufacturing Systems, Venkatesh Kurapati

Dissertations

Global competition has made it necessary for manufacturers to introduce such advanced technologies as flexible and agile manufacturing, intelligent automation, and computer-integrated manufacturing. However, the application extent of these technologies varies from industry to industry and has met various degrees of success. One critical barrier leading to successful implementation of advanced manufacturing systems is the ever-increasing complexity in their modeling, analysis, simulation, and control. The purpose of this work is to introduce a set of Petri net-based tools and methods to address a variety of problems associated with the design and implementation of flexible manufacturing systems (FMSs). More specifically, this ...


Theory, Design And Applications Of Linear Transforms For Information Transmission, Adil Benyassine Dec 1994

Theory, Design And Applications Of Linear Transforms For Information Transmission, Adil Benyassine

Dissertations

The aim of this dissertation is to study the common features of block transforms, subband filter banks, and wavelets, and demonstrate how discrete uncertainty can be applied to evaluate these different decomposition techniques. In particular, we derive an uncertainty bound for discrete-time functions. It is shown that this bound is the same as that for continuous-time functions, if the discrete-time functions have a certain degree of regularity.


On Adaptive Code Division Multiple Access Detectors, Wenping Chen Dec 1994

On Adaptive Code Division Multiple Access Detectors, Wenping Chen

Dissertations

Several variations of adaptive CDMA synchronous receiver schemes which can automatically adjust to the system parameters, are studied in this dissertation. Unlike their non-adaptive counterparts, these adaptive detectors require no knowledge of the received signals' energies and have similar or better performance.


Robust Approach To Object Recognition Through Fuzzy Clustering And Hough Transform Based Methods, Tianxiong Fu Dec 1994

Robust Approach To Object Recognition Through Fuzzy Clustering And Hough Transform Based Methods, Tianxiong Fu

Dissertations

Object detection from two dimensional intensity images as well as three dimensional range images is considered. The emphasis is on the robust detection of shapes such as cylinders, spheres, cones, and planar surfaces, typically found in mechanical and manufacturing engineering applications. Based on the analyses of different HT methods, a novel method, called the Fast Randomized Hough Transform (FRHT) is proposed. The key idea of FRHT is to divide the original image into multiple regions and apply random sampling method to map data points in the image space into the parameter space or feature space, then obtain the parameters of ...


Design And Micro-Fabrication Of Tantalum Silicide Cantilever Beam Threshold Accelerometer, Chang Joo Kim Dec 1994

Design And Micro-Fabrication Of Tantalum Silicide Cantilever Beam Threshold Accelerometer, Chang Joo Kim

Dissertations

Microfabricated threshold accelerometers were successfully designed and fabricated following a careful analysis of the electrical, mechanical, and fabrication issues inherent to micron-sized accelerometers. A uniform cantilever beam was chosen because of the simplicity of design and fabrication. New models for the electrostatic force exerted on the cantilever beam were developed and calculations were made that accurately predicted the electrical characteristics of the accelerometer. The calculations also provided design guidelines for optimizing the accelerometer dimensions. Computer simulation demonstrated that the error of the electrostatic force, calculated using the most accurate model, was within 2% of the actual force which was obtained ...


Electrical Characteristics Of Novel Heterojunction Diodes Of Thin Relaxation Semiconductors/P-Si/, Hyung Joo Lee Dec 1994

Electrical Characteristics Of Novel Heterojunction Diodes Of Thin Relaxation Semiconductors/P-Si/, Hyung Joo Lee

Dissertations

The relaxation semiconductor is defined as one in which the dielectric relaxation time (τd;resistivity times permittivity) is greater than lifetime (τo). Non-hydrogenated amorphous Silicon Carbide (SiC) and KrF excimer laser induced disordered Si were used for the relaxation semiconductors. Both semiconductors have high resistivity, wide energy gap, and numerous defects. A novel diode, consisting of those semiconductors on p-type crystalline Silicon (c-Si), was fabricated. In the diode structure, an injecting contact was made on the relaxation material and a Schottky barrier contact was made on the c-Si.

Electrical characteristics of both diodes were found to have interesting effects ...


Combustion Of Methyl Chloride, Monomethyl Amine, And Their Mixtures In A Two Stage Turbulent Flow Reactor, Fuhe Mao Dec 1994

Combustion Of Methyl Chloride, Monomethyl Amine, And Their Mixtures In A Two Stage Turbulent Flow Reactor, Fuhe Mao

Dissertations

The feasibility of converting fuel-bound chlorine and nitrogen into HCl and N2 with reduced pollutant emissions of CO, NO, and unburned hydrocarbons was investigated in a two-stage turbulent flow reactor. The study consists of four segments: completion and validation of the experimental facility, experimental and modeling studies of methyl chloride (CH3Cl) combustion, similar studies on monomethyl amine (CH3NH2), and finally studies on simultaneous CH3Cl and CH3NH2 combustion.

Validation of the experimental facility was made by combustion of ethylene (C2H4) and air under both fuel-lean and fuel-rich ...


Analysis Of Plates And Reinforced Concrete Columns By Cubic B-Spline Function, Gang Wang Dec 1994

Analysis Of Plates And Reinforced Concrete Columns By Cubic B-Spline Function, Gang Wang

Dissertations

Applying spline functions to numerical structural analysis has been more common in recent years. The recent increase use of spline functions is mainly due to their excellent characteristics, such as sectionalized continuity, linear combination, flexibility, and easy use for various boundary conditions. The whole deformed shape of some structures or substructures can be described with one displacement function constructed by a series of spline functions. By doing this, the mesh generation and the huge computer memory space are no longer needed because only one single superelement can be used in the whole process. The choice of spline functions as displacement ...


Wear And Friction Of Hylamer And Polyethylene Against Cobalt Chromium A Pin-On-Disc Study, Jerry D'Alessio, Ii Dec 1994

Wear And Friction Of Hylamer And Polyethylene Against Cobalt Chromium A Pin-On-Disc Study, Jerry D'Alessio, Ii

Theses

Understanding friction and wear of biomaterials is essential to the success of any prosthetic joint. A pin-on-disc wear tester is used to find the friction and wear of pins of one material on a coupon of medical grade cobalt chrome. In this experiment six pins of UHMWPe (ultra high molecular weight polyethylene) and six pins of Hylamer® from Du Pont Manufacturing were tested. Four separate runs were made. The tests were performed for ten million cycles, stopping every one to one and a half million cycles for data acquisition. Volumetric wear, wear rate, and coefficients of friction were measured. Both ...


An Adaptive Asynchronous Cdma Receiver And Its Convergence Analysis, Lizhi Zhong Dec 1994

An Adaptive Asynchronous Cdma Receiver And Its Convergence Analysis, Lizhi Zhong

Theses

An adaptive CDMA receiver scheme assuming perfect synchronization has been generalized in this thesis to the asynchronous channel, a much more practical assumption of the real system. Similar formulas are derived and as its synchronous version, it is still near-far resistant and requires no knowldge [sic] of received signal amplitudes and training sequences. Thus, sophisticated high-precision power control and user power estimation are not necessary and the receiver is particularly useful in mobile communications since it can adjust itself adaptively to changes in the power of the users. Tile convergence and transient behavior of the receiver are also investigated and ...


Heart Rate Variability Studies On Ambulatory Subjects Using Ekg Derived Respiration, Xiaorui Tang Dec 1994

Heart Rate Variability Studies On Ambulatory Subjects Using Ekg Derived Respiration, Xiaorui Tang

Theses

Power spectral analysis of heart rate variability (HRV) provides a powerful non-invasive too] for exploring the balance between sympathetic and parasympathetic components of the autonomic nervous system. In the spectrum of HRV, there are three distinct peaks. The high frequency (HF) band (0.15 to 0.4 Hz) is correlated with parasympathetic activity and this is the band of interest 'in the study.

Two OTOUPS Of SL113jeCtS were considered in this work, stroke survivors and subjects performing an oral presentation in front of an audience. Data were collected with a Holter monitor to allow for ambulatory recording. Respiration was derived ...


Stress-Strain Behavior Of High Strength Concrete Cylinders, Danqing Chen Dec 1994

Stress-Strain Behavior Of High Strength Concrete Cylinders, Danqing Chen

Theses

Due to the recent development of high strength concrete in engineering and construction, it has become more important to study the behavior of materials in structures.

No results have been previously published in the literature regarding the influence of aspect ratio in plain high strength concrete cylinders on stress-strain behavior under uniaxial compression.Thus at present study, compression tests were conducted on 3x6 in., 3x9 in., and 3x12 in. plain high strength concrete cylinders to study their stress-strain behavior. Plain normal strength concrete cylinders were also tested and used for comparative study.

Based on the present investigations, attempting to obtain ...


Single-Axis Agonistic Motion Control System With Electro-Magnetic Actuators, Alexander Rokhvarg Dec 1994

Single-Axis Agonistic Motion Control System With Electro-Magnetic Actuators, Alexander Rokhvarg

Theses

A novel single-axis motion control system using solenoid electromagnet actuators is built and successfully controlled using a non-linear real-time control algorithm. Procedures for defining and modeling the electromagnetic actuator are established and implemented. Discrete-time nonlinear control law with global asymptotic stability and zero steady-state error is designed and numerically optimized. Stable operation with small-signal 0dB crossover frequency of 370 Rad/sec and positioning RMS steady-state error of better than 4 micron is achieved. Time domain parameters are verified on a working prototype. A step reference response positioning a 0.35 Kg mass payload over 1 cm travel in under 30 ...


Model Parameter Identification For Rod And Cone Oscillatory Potentials, Kehur Banker Dec 1994

Model Parameter Identification For Rod And Cone Oscillatory Potentials, Kehur Banker

Theses

The use of signal modeling of the oscillatory potential (OP) of the electroretinogram (ERG), in the study of cone-rod interaction is investigated. ERG response data were analyzed for red, orange, blue and white flashes on no background and with red flashes on a blue background (to suppress rod responses). The OP signals were extracted from the ERG by digital bandpass filtering and a signal model was fitted through a simplex algorithm to produce the parameters including "OP envelope-amplitude", latency in terms of "center-time" of the OP-envelope and OP frequency. Amplitude for red flashes with or without a blue background showed ...


Development Of A Multi-Lead Trans-Thoracic Impedance Pneumograph For Heart Rate Variability Studies, Curtis Bashford Dec 1994

Development Of A Multi-Lead Trans-Thoracic Impedance Pneumograph For Heart Rate Variability Studies, Curtis Bashford

Theses

In this study, a device that measures respiratory tidal volume and ECG for use in heart rate variability studies, was designed, built and tested. The device developed is a Multi-Lead Trans-Thoracic Impedance Pneumograph, which determines tidal volume on a breath by breath basis, utilizing both hardware and software. It uses standard ECG electrodes which provide increased comfort and inability to the subject over traditional spirometry methods. The device operates similar to traditional bipolar impedance pneumographs except that instead of only one lead (electrode pair), four leads are acquired simultaneously using time-division multiplexing; providing data from different locations and vectors on ...


Time Domain And Frequency Domain Analysis Of Myoelectric Signals During Muscle Fatigue, Rakesh M. Maniar Dec 1994

Time Domain And Frequency Domain Analysis Of Myoelectric Signals During Muscle Fatigue, Rakesh M. Maniar

Theses

Spectral analysis of the EMG signal is a useful tool for studying the complex phenomena of fatigue. The spectral parameters of mean frequency and median frequency, and the time domain parameter of root mean square have been used to measure localized fatigue.

The normal values of median frequency and its decline with fatigue have not as yet been determined in healthy subjects. This should be done in order to apply spectral analysis for clinical evaluations of abnormal populations. Normal median frequency values and its slope were established in this work for the upper extremity muscles of biceps, triceps and deltoid ...


Simulation Study Of Particle Tracking System, Prashant B. Patel Dec 1994

Simulation Study Of Particle Tracking System, Prashant B. Patel

Theses

A particle tracking system is being developed in the Particle Technology Laboratory of the Mechanical Engineering Department, at NJIT, In this thesis, an attempt is made to understand the effect of various parameters on the errors in the computed position and orientation of the sphere being tracked. Simulation results for a single transmitter assembly as well as a three transmitter assembly with 6, 9 and 17 antennae are presented. The effects of the level of noise in the voltages on the solution for the single transmitter assembly and three transmitter assembly are discussed. The concept of virtual antenna is introduced ...


Soft Decision Adaptive Multiuser Cdma Detector For Asynchronous Awgn Channels, Frank Viehofer Dec 1994

Soft Decision Adaptive Multiuser Cdma Detector For Asynchronous Awgn Channels, Frank Viehofer

Theses

A multiuser detector in an asynchronous, additive white Gaussian noise, codedivision multipleaccess (CDMA) channel is proposed and analyzed. It employs a combination of a decorrelator and a nonlinear multiuser interference canceler that utilizes soft tentative decisions. The weights of the canceler are adaptively adjusted, in a manner that renders the knowledge of received signal energies and the use of training sequences unnecessary. The steady state error performance of the detector is obtained and found to be superior to the performance of the same detector that utilizes hard tentative decisions.


Aeration And Operation Of An Immobilized Cell Oxidative Bioreactor, James Joseph Woods Dec 1994

Aeration And Operation Of An Immobilized Cell Oxidative Bioreactor, James Joseph Woods

Theses

The primary purpose of this work is to help define the optimum window of operations for an immobilized cell oxidative bioreactor. The analytical technique employed requires no outside verification (such as G.C. analysis) and is independent of liquid flow rate. Method of aeration has been determined to be an important parameter for optimizing bioreactor efficiency, and optimization of the quantity of hydrogen peroxide added to provide oxygen during bio-oxidation has been investigated. Ammonium hydroxide as a fixed nitrogen source can be used to restore the vitality of the bioreactor under certain conditions.

The effects of several different methods of ...


Implementation Of Time-Frequency Distribution Software And Its Use To Study Biological Signals, Mansour Adib Dec 1994

Implementation Of Time-Frequency Distribution Software And Its Use To Study Biological Signals, Mansour Adib

Theses

The joint time-frequency signal representation has received considerable attention as a powerful tool for analyzing biological signals. It combine time-domain and frequency-domain analyses to yield a potentially more revealing picture of the temporal localization of a signal's spectral components. In this research we have developed algorithm which implement time-frequency signal analysis techniques on a computer system. Its primary function is to produce a variety of time-frequency representations and plots from the time series. Numerous generated signals were used to justify our computer algorithm.

Variety of time-frequency distribution were utilized to expand the concept of spectral analysis of heart rate ...


Use Of Multiple Transmitters For 3-D Non-Intrusive Particle Tracking, Jitesh H. Agrawal Dec 1994

Use Of Multiple Transmitters For 3-D Non-Intrusive Particle Tracking, Jitesh H. Agrawal

Theses

A method for non-intrusive tracking of a particle in 3-dimensional space, based on processing of signals emitted from a transmitter embedded in the particle, is being developed. This method uses a mathematical model, which predicts the induced signal in receivers present in the vicinity of flowing particle, and supporting numerical techniques. Specific application aspects related to improving the accuracy of this method are presented.

The focus here is the development of flexible software capable of processing information coming from multiple transmitters with known distinct spatial orientation. Implementation aspects of modified existing empirical corrections for improving model-reality agreement, and new techniques ...


Wear Of Polyethylene And Hylamer On Cobalt-Chromium : A Knee Simulator Study, Alessandro F. Canonaco Dec 1994

Wear Of Polyethylene And Hylamer On Cobalt-Chromium : A Knee Simulator Study, Alessandro F. Canonaco

Theses

Two tests were conducted to examine the wear characteristics of tibial bearings used in total knee replacement systems. Each test consisted of six A/P Glide Tibial Bearings each having a conical control arm. The plastic portion of the conical bearings were all made of UHMWPe. Each of these bearing systems was mounted onto a Co-Cr alloy tibial platform and Co-Cr alloy LCS (low contact stress) femoral component . These test samples were mounted onto the New Jersey Mark III Knee Simulator System. The simulator was configured to produce flexion and axial rotation to simulates normal gait. Each test ran at ...