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Articles 2161 - 2190 of 3460

Full-Text Articles in Engineering

Eeg Mapping Using The Personal Computer, Zhuan-Zhang Pei May 1990

Eeg Mapping Using The Personal Computer, Zhuan-Zhang Pei

Theses

An approach for brain electrical activity mapping using a personal computer has been investigated to enhance the visibility of the EECs. An automatic procedure from data acquisition to the final mapping has been developed for on-line or off-line data processing, in which a table-look-up technique has been introduced to eliminate redundant processing. The power spectra in different EEC frequency bands for four electrodes are coded into 15 colors and mapped on a color monitor. The data correspondings to the areas between electrodes are interpolated by the surface spline method. The mapping speed and smoothness has been optimized. An experiment has …


Performance Studies Of Lapped Orthogonal Transforms, Frank E. Wadas May 1990

Performance Studies Of Lapped Orthogonal Transforms, Frank E. Wadas

Theses

The comparative performance of several Lapped Orthogonal Transforms(LOTs) [1][2][3][12] is studied in this thesis . Blocking effects of conventional block transforms at low bit rates are reduced with LOT, through basis functions that overlap in adjacent blocks. The block transforms of Discrete Cosine Transform (DCT), Discrete Sine Transform (DST)[4], Discrete Legendre Transform (DLT), and the Modified Hermite Transform (MHT)[16] are extended to LOT in a way that a fast algorithm for nearly optimal LOTs is derived. The Markov and two different exponential correlation models are used as the source models for the derivation of these LOTs. It is shown that …


Behavior Of Slender High Strength Steel Fiber Reinforced Concrete Columns Under Combined Biaxial Bending And Axial Compression, Tzuoh-Jaw Wu May 1990

Behavior Of Slender High Strength Steel Fiber Reinforced Concrete Columns Under Combined Biaxial Bending And Axial Compression, Tzuoh-Jaw Wu

Theses

A total of four slender high strength steel fiber ( 20 vol. hooked ends 1 in and 2 in ) reinforced concrete columns were casted, cured and tested to failure under biaxially eccentric load us—KT MTS testing system. The experimental load-deflection behavior exhibits not only the ascending branch but also the descending branch of the load and deformation curves.

The experimental ultimate load capacity was analyzed by the equation of Failure Surface Method developed by Hsu. recently, the result shows that the analysis method is able to predict the ultimate load value for biaxially loaded slender concrete columns.

For biaxially …


Automatic Infrared Inspection Of Solder Joints On Mounted Circuit Boards, Ken Kekuan Zhou May 1990

Automatic Infrared Inspection Of Solder Joints On Mounted Circuit Boards, Ken Kekuan Zhou

Theses

This thesis reports the research work on automatic infrared and visual light inspections of solder joints on printed circuit boards (PCBs) utilizing an image processing system and statistical pattern recognition techniques.

A small scale image processing system, consisting of a SUN workstation and several DATACUBE modules, is set up for the research. Software packages for imaging, displaying and solder joint inspection are developed and ready for public usage.

The capability of infrared inspection for solder joints on PCBs is demonstrated. The fusing of infrared and visual light imagery for the inspection is shown to offer better results than that obtainable …


Image Data Compression With Neural Networks, Jianjun Li May 1990

Image Data Compression With Neural Networks, Jianjun Li

Theses

Three efficient image coding schemes, based orb neural networks, have been developed in this thesis: (1) Neural network vector quantization (NNVQ). The main advantage of this new technology is that it can accomplish the complex encoding process much faster than the previous algorithms. Its properties are studied and demonstrated by simulations. (2) A adaptive NNVQ for image sequence coding. Simulation experiments have been carried out with 4 x 4 blocks of pixels from an image sequence consisting of 40 frames. At 0.67 bits/pixel, this scheme achieves good image quality suitable for videoconferencing systems; (3) Neural network prediction. This new prediction …


Trellis Coded Tamed Frequency Modulation In Rayleigh Fading Channels, Kiran R. Patel May 1990

Trellis Coded Tamed Frequency Modulation In Rayleigh Fading Channels, Kiran R. Patel

Theses

It is usually difficult to reduce the effects of channel impairements on transmitted information. A fading channel is one such media in which digital communications system operates. A signal is subject to distortion in amplitude and phase when propagating towards the receiver. This puts constraint in required SNR at the receiver, for given performance. Various modulation/coding and demodulation/decoding techniques are employed to lessen the effects of fading. Bit error rate is a performance parameter that sets the criteria for signal design, system architecture and performance.

Here, a slow Rayleigh fading channel with three propagation paths possesing a scattering function of …


Mathematical Modeling And Computer Simulations Of Biodenitrification In Batch And Sequencing Batch Reactors, Sugata Sanyal May 1990

Mathematical Modeling And Computer Simulations Of Biodenitrification In Batch And Sequencing Batch Reactors, Sugata Sanyal

Theses

Mathematical models have been derived for describing biodegradation of ni¬trate and nitrite in an anaerobic environment. Monod model for nitrate and Andrews model for nitrite were used as kinetic models. Experimental data from literature suggest that nitrate is not an inhibitory substance, while nitrite is not only inhibitory but it may also have a toxic effect on the biomass. The models were brought in dimensionless form in order to reduce the number of parame¬ters. Biodegradation was mathematically described for a batch, and a sequencing batch mode of operation. Computer programs were developed for numerically simulating the process. Some of the …


Interconnection Of X.25 Networks, Syed Ayaz Qutubuddin Ahmed May 1990

Interconnection Of X.25 Networks, Syed Ayaz Qutubuddin Ahmed

Theses

The purpose of this work was to investigate the performance of two interconnected X.25 networks via CCITT internet protocol X.75. Since internet protocol X.75 follow the same flow approach as X.25, we are allowed to model the acknowledgement queue in such a way that this queue provides a feed back path from destination to the source queue. Thus we are able to model our interconnected network as a closed queueing network with limited number of packets in transit within the network. Mean Value Analysis with Blocking (MVA) algorithm was applied to obtain the performance characteristics as the resources available were …


Application Research On Wastewater Reuse For Petrochemical Refining Industry In Taiwan, Lih-Shyan Lee Jan 1990

Application Research On Wastewater Reuse For Petrochemical Refining Industry In Taiwan, Lih-Shyan Lee

Theses

Nowadays water conservation and pollution abatement are needed to provide increasingly higher levels of treatment for industrial wastewaters.

Reducing treatment costs give us the incentive to minimize the volume of Wastewater effluent. Also, the national goal of zero discharge of pollutants to the waterways by 1985 provided further incentive -to minimize the flow of wastewaters.

A successful treatment of the wastewater discharged from the secondary effluent of the petroleum refinery plant to economically acceptable conditions offers a challenge to our technology.

Through this research, it is concluded that the excellent effluent water qualities produced from filtration and granular activated carbon …


Synthesis And Study Of Polymers Containing Inorganic Ions, Lateef Aderoju Ibikunle-Sofoluwe Jan 1990

Synthesis And Study Of Polymers Containing Inorganic Ions, Lateef Aderoju Ibikunle-Sofoluwe

Theses

Cupric and ferrous polyacrylates have been prepared and studied. It was thought that partial reduction of Cu2+ or Fe3+ or oxidation of Cu+ or Fe2+ might result in semiconducting behavior but no such effect has been observed. Nevertheless, the results obtained are of considerable interest. Quantitative gravimetric and volumetric studies of cupric polyacrylate precipitation from varying molar ratios of cupric chloride and sodium polyacrylate in aqueous solution have shown that the only product formed is Cu(PA)2 (Where PA represents an acrylate mer in polyacrylate). The insolubility of the product indicates that much of the Cu …


Dioxin Formation : Thermodynamics And Reaction Pathways During The Oxidation/Incineration Of Chloroaromatics, Sanjiv Narendra Patel Jan 1990

Dioxin Formation : Thermodynamics And Reaction Pathways During The Oxidation/Incineration Of Chloroaromatics, Sanjiv Narendra Patel

Theses

Enthalpy, entropy and heat capacity property estimation for cyclic molecules using Benson's group additivity method require the use of ring correction terms. Ring correction terms are estimated from the thermodynamic properties of the cyclic molecule being considered. In the absence of litera¬ture values a procedure is proposed to predict these thermodynamic values.

Benson's Group additivity method does not fully account for the interactions between bulky group or atom substituents on the aromatic ring. In order to have accurate thermodynamic properties for these compounds, a data base is generated with ortho, meta and Para interactions for (Cl-Cl), (Cl-OH), (OH-OH), (CH3 …


Fault Tolerant Benes Networks, Manoj Bhatnagar Jan 1990

Fault Tolerant Benes Networks, Manoj Bhatnagar

Theses

A fairly large number of fault tolerant topologies have been proposed for the multistage interconnection networks in the recent years. However very few of these schemes have focused on the Benes network. This thesis presents two new fault tolerant architectures for the Benes network. The thesis includes algorithms to construct these fault tolerant networks from a Benes network and the reconfiguration procedure in the event of a fault. The hardware characteristics of both the fault tolerant networks have been analyzed and compared.


Uniformity Corrector And Signal Processing For A 160 X 244-Element Ir-Ccd Camera With Ptsi Schottky-Barrier Detectors, Paul D. Blume Jan 1990

Uniformity Corrector And Signal Processing For A 160 X 244-Element Ir-Ccd Camera With Ptsi Schottky-Barrier Detectors, Paul D. Blume

Theses

An off-set-type, one point response uniformity corrector and the associated signal processing circuits was developed to be used for a 160 x 244-element IR-CCD camera with PtSi Schottky-barrier detectors. Image sensors with PtSi Schottky-barrier detectors exhibit two types of noise in the displayed video output, a temporal noise and a spatial fixed pattern noise. The performance of the image sensor, limited by the spatial noise which obscures low contrast detail and limits camera sensitivity, can be improved by a uniformity corrector. The uniformity corrector was constructed to substantially reduce the spatial noise in the output display by digitally subtracting a …


Investigation Of The Fluid Dynamics Of Bioprosthetic Heart Valves, Carol A. Calta Jan 1990

Investigation Of The Fluid Dynamics Of Bioprosthetic Heart Valves, Carol A. Calta

Theses

There is a strong connection between altered arterial blood flow and vascular disease. The presence of disturbed flow and/or excessive turbulence is an indication of an abnormality within the cardiovascular system. The examination of cardiovascular fluid dynamics provides insights into the working of the cardiovascular system and ways to improve the design of implantable bioprosthetic valve designs. This investigation examines the fluid flow of arterial systems, and ways to apply this knowledge to the valves implanted into patients.

This thesis involves an investigation of the testing of bioprosthetic valves within simulated left heart flow loops. These systems include pulse duplicators …


Formation And Characterization Of Thin Superconducting Y-Ba-Cu-O Films, Gyusuk Kim Jan 1990

Formation And Characterization Of Thin Superconducting Y-Ba-Cu-O Films, Gyusuk Kim

Theses

Thin Y-Ba-Cu-O superconducting films were fabricated reproducibly on MgO (100) substrates by two different processes ; (1) deposition at a low substrate temperature fiom a single sintered YBa2Cu3.3Ox target using RF diode reactive sputtering followed by a post-annealing at around 830 ° C ; (2) deposition at the crystallization temperature under oxidizing atmosphere. The superconducting properties of films deposited by process (1) and (2) were studied. The variation of film composition and thickness as a function of distance from the target gas pressure and distance between target and substrate was studied. The Dependence of the …


Three-Dimensional Stress Analysis Of The Femoral Midshaft Utilizing Computed Tomography And Finite Element Analysis, Peter F. Marion Jan 1990

Three-Dimensional Stress Analysis Of The Femoral Midshaft Utilizing Computed Tomography And Finite Element Analysis, Peter F. Marion

Theses

Recent advances in computer technology have provided both the medical community and biomedical engineers with a method for noninvasively evaluating the internal structure in a way not previously possible. A three-dimensional finite element model of a midshaft section of the femur was generated, utilizing Computed Tomography scan data. The CT scan data file was introduced into an edge-detection algorithm and a file of geometric edge data was generated. This edge data was introduced into a solid modeling Computer-Aided Engineering software package to produce a three-dimensional solid model. A mesh generation procedure was then used to create a three-dimensional finite element …


Desiccation And Permeability Of Backfill Materials In Soil-Bentonite Walls, Hemendra J. Moradia Jan 1990

Desiccation And Permeability Of Backfill Materials In Soil-Bentonite Walls, Hemendra J. Moradia

Theses

Soil-Bentonite Walls offer a cost effective solution to many groundwater problems in new and remedial work projects such as hydraulic barriers in dams, dewatering large soil cuts, and as part of pollution control systems around hazardous waste landfills. However, the performance of soil-bentonite walls in environments other then fresh water types is still a matter of great controversy. In recent years, some data on soil-bentonite backfill have became available. The data indicate change in properties of these walls with time of exposure and concentration of chemicals found in leachates. However, no research work is available in the literature on the …


The Magnetotransport Analysis Of Hemt Structures At Low Fields, Naghmeh Nouri Jan 1990

The Magnetotransport Analysis Of Hemt Structures At Low Fields, Naghmeh Nouri

Theses

On the basis of a study on numerous HEMT structures, a simple and useful technique was established for the characterization of 2DEG layers. This technique utilizes the magnetic field-dependence of the resistivity and Hall coefficient of the HEMT structure, to determine the values of the sheet density and mobility of 2DEG in the presence of other parallel conductive layers. This method of analysis was compared with previously used techniques such as Shubnikov-de Haas and the etch removal of the parallel conductive layers. Through this comparison and several measurements it was found that this procedure gives reproducible values for the 2DEG …


Adaptive Fir Digital Filter Design And Simulation In The Noise Reduction System, Jack Jiabing Pang Jan 1990

Adaptive Fir Digital Filter Design And Simulation In The Noise Reduction System, Jack Jiabing Pang

Theses

The adaptive FIR digital filter is designed to suppress the noise in the tape recording and audio communication systems. The cutoff frequency of the digital FIR filters can be varied adaptively depending on the energy level of the input signal. In audio communication, especially, in tape recording systems, the noise obviously gets much bigger, when the frequency band of the system increases. The noise reduction system makes use of a phenomenon called masking, where the big signal-to-noise ratio makes human ears not sensitive to the noise. In a constant interval time, the system detects the signal level and compares the …


Computer Integrated Manufacturing : A Systems Approach For Small Manufacturing Enterprises, Sanjeet Jagdish Patel Jan 1990

Computer Integrated Manufacturing : A Systems Approach For Small Manufacturing Enterprises, Sanjeet Jagdish Patel

Theses

This work is dedicated to small manufacturing enterprises seeking to explore Computer Integrated Manufacturing (CIM) technology, which is the recent trend in the manufacturing world. The main therie of this thesis is to improve productivity, product quality and reliability and reduce costs by integrating various disciplines.

Generic manufacturing functions including order entry, inventory control, manufcturing planning and control, automated drafting, direct numerical control etc. were enhanced by the effective utilization of low end workstations grouped together into a network and equipped worth industry standards software.

The introduction of computers into a manually resourced system yielded significant results such as reduction …


Sputter Deposition And Characterization Of High Tc Superconducting Thin Films, Vipulkumar Patel Jan 1990

Sputter Deposition And Characterization Of High Tc Superconducting Thin Films, Vipulkumar Patel

Theses

Preparation of thin superconducting films by direct RF sputter deposition on Si, MgO, SrTiO3 and quartz substrates and silver and Sl3N4 buffer layers (deposited on silicon substrates) was studied. To study resistance versus temperature characteristics of thin films and bulk materials, a computerized measurement system was developed. 1-1.5 pm thick YBaCuO films deposited on Si3N4/Si were found to be insulating with room temperature resistance higher than 236KΩ, while films with Ag as a buffer and/or a passivating layer exhibited metallic behavior with room temperature resistances lower than 700mΩ. The area directly under the 2.25 inches …


Testing And Modelling Of The Cleaner Wick System For In-Situ Treatment Of Contaminated Groundwater Plumes, Sanjiv I. Shah Jan 1990

Testing And Modelling Of The Cleaner Wick System For In-Situ Treatment Of Contaminated Groundwater Plumes, Sanjiv I. Shah

Theses

The cleaner wick system, a modification of wick drains; a technology in recent use to consolidate low permeability soils, is proposed to treat contaminated groundwater plumes. Laboratory experiments on surrogate contaminants produce satisfactory results. Theoretical models are developed utilizing the cleaner wick system to treat volatile organic contaminants by air stripping and adsorption on granular activated carbon.


Treatment Of Trucking Station Wastewater By Two-Phase Anaerobic Digestion System And Rotating Biological Contactor, Tzu-Wen Uen Jan 1990

Treatment Of Trucking Station Wastewater By Two-Phase Anaerobic Digestion System And Rotating Biological Contactor, Tzu-Wen Uen

Theses

The wastewater produced as a result of trucking station activities has some major characteristics such as high COD (26,880 mg/1-42,925 mg/1) and BOD (12,278 mg/1-7,265 mg/1), high COD to BOD ratio (3.49-3.69), high pH range (3.72-11.7), and high grease content (480 mg/1-1,960 mg/1). Therefore, prior to any treatment, it is important to provide some sort of pre-treatment for pH adjustment and grease/oil removal.

The present laboratory investigation has indicated that successful treatment and purification of the subject wastewater is possible using two-phase anaerobic digestion system followed by rotating biological contactor. More than 90% of both COD and BOD was removed …


Development Of A Flexible Control And Automated Data Acquisition System For Wear Testing, Wen-Long Yao Jan 1990

Development Of A Flexible Control And Automated Data Acquisition System For Wear Testing, Wen-Long Yao

Theses

The purpose of this work is to develop a flexible control and automated data acquisition system for wear testing procedure. A programmable logic controller (PLC) control philosophy and PC-based automated data acquisition system (DAS) were designed and organized for the wear testing machine in Surface Engineering Laboratory of Mechanical Engineering Department. The designed and performed separation of control and acquisition strategies saved a lot of engineering interface communication time. Several instrumentations and mechanism designs, such as selected RTD sensor, modified testing shoe for RTD installation, designed controlled lubrication mechanism, and designed load-unload mechanism, have been performed to fulfill the concerned …


Simulation And Design Of Field Emission Diode, Yun Yuan Jan 1990

Simulation And Design Of Field Emission Diode, Yun Yuan

Theses

A new generation of microelectronic devices utilizing vacuum field emission cathodes becomes surging interest in recent years. This paper concentrates on the study of the field emission diode — a basic vacuum microelectronic device. The field emission efficiency, current spatial distribution and time dispersion of conical tips and wedges of various geometrical shapes are compared and calculated by analytical methods and computer simulations. Two field emitter heating effects, namely the Joule heating and Nottingham effect, are discussed theoretically. All the simulation results in this paper are performed on 386 based personal computer. The limiting memory space of PC induced simulation …


Kinetic Mechanism Of The Reactions Of Dichloromethane And Chloroform With Atomic Hydrogen At Low Pressure And Room Temperature, Jia-Ling Linda Young Jan 1990

Kinetic Mechanism Of The Reactions Of Dichloromethane And Chloroform With Atomic Hydrogen At Low Pressure And Room Temperature, Jia-Ling Linda Young

Theses

The reaction mechanism of dichloromethane reaction (DCM) with atomic hydrogen in a flow reactor at room temper¬ature (300 K) and low pressure (2.1 - 2.7 torr), argon bath gas, has been developed in this research to analyze the above reaction system. The important addition reactions of radicals (or atoms) to olefins and the radical/radical (atom/radical) combination reactions have been analyzed using the bimolecular version of the Quantum-Rice-Ramsperger-Kassel (QRRK) theory.

The detailed reaction mechanism satisfactorily fits the experimental data for the reagent (DCM) conversion from previous experimental over a initial ratio (atomic hydrogen to dichloromethane) range of 6.8 to 40. The …


Infrared Tv Camera With Ptsi Schottky-Barrier Detectors, Steven J. Blume Jan 1990

Infrared Tv Camera With Ptsi Schottky-Barrier Detectors, Steven J. Blume

Theses

An infrared TV camera was developed for operating various sizes of Schottky-barrier IR-CCD image sensor chips. A digitally programmable frequency synthesizer is used so that the camera has the flexibility of using a 160 x 244 or 320 x 244 image sensor developed at the David Sarnoff Research Center. The outputs of the camera are compatible with an XYZ monitor, a standard TV monitor, and a computer workstation. Operation of the camera was demonstrated with a 160 x 244 image sensor producing an output on a standard TV monitor. Performance of the IR-TV camera system was investigated by evaluating CCD …


Performance Analysis Of A Dynamic Reservation Multichannel Local Area Network, Abubakar A. Ibrahim Jan 1990

Performance Analysis Of A Dynamic Reservation Multichannel Local Area Network, Abubakar A. Ibrahim

Theses

A reservation multiaccess protocol. is proposed to be used on multichannel local area networks. This protocol is advantageous for networks supporting integrated services. The delay and throughput performance for message transmission are obtained by analysist The delay performance of the protocol is similar to the M-CSMA/CD/IC multichannel network proposed by Marsan and Roffinella. It is found that the reservation protocol can provide better throughput-delay characteristics when the fraction of the total available bandwidth allocated to data is increased. It is also observed that the maximum throughput increases with the increase in the number of channels when the total bandwidth is …


The Design Of Decentralized Optimal Regulator Systems Using Matrix Minimum Principle, Sunny Lai Yick Jan 1990

The Design Of Decentralized Optimal Regulator Systems Using Matrix Minimum Principle, Sunny Lai Yick

Theses

This research considers the design of linear, time-varying regulator systems using Matrix Minimum Principle in the frame work of decentralized control theory. The regulator system is modeled in terms of state equation with multiple controllers. Each controller works cooperatively to optimize a common quadratic performance index. An additional constraint is imposed such that the controllers are linear time-varying functions of the outputs.

Necessary and sufficient conditions for optimality of the system are provided by the Matrix Minimum Principle and Hamilton-Jacobi Theory.

Two examples are developed to illustrate the concept.


Analytical And Experimental Study Of Robotic Peg-In-Hole Insertion, Yilun Jia Jan 1990

Analytical And Experimental Study Of Robotic Peg-In-Hole Insertion, Yilun Jia

Theses

A mathematical model of robotic peg-in-hole insertion, which relates insertion force and moment to manipulator compliance and geometric constraints, is presented. Based on this model, the effects of manipulator compliance and geometric and positional parameters on the insertion are studied. The complete expressions for determining the insertion forces and moment as well as the peg kinematics are derived. The study is helpful to reducing insertion force and moment and avoiding possible jamming during the insertion process. The model is verified experimentally on the IBM 7540 robot.