Engineering Commons^™

Reflection And Transmission Through Achiral-Chiral Interface, Jia-Feng Wang

Theses

Electromagnetic wave propagation through an achiral-chiral interface is analyzed via Maxwell's equations using the appropriate boundary conditions. Experimental data for reflected power from achiral-chiral interface was found to be in qualitative agreement with the analytical results. In addition, coupled mode equations for chiral cladding waveguides were derived and solved for weak coupling. The experimental results of chiral cladding waveguides show that an average of about 0.2° per cm in polarization rotation occurred. These waveguides were fabricated by using spin-coating deposition. The sense of the rotation was found to be independent of the handness of the cladding chirality, which was predicted …

Modeling And Analysis Of Electrical Properties Of Polycrystalline Silicon Films, Yunsheng Wang

Theses

In recent years, investigations on polysilicon grain structures have shown that all polysilicon films by LPCVD which are most used in today's integrated circuits are columnar in structure. In this work, a square columnar grain structure has been considered to model electrical properties of polycrystalline silicon films instead of all previous one-dimensional grain structure models. By solving Poisson's equation with certain boundary conditions, we find that the barrier height at the corners of the grain is lower than that in the one-dimensional case. Assuming the trapping state energy level as constant, we also find that this level has a value …

Microengineered Silicon Beam Switch For Fiber Optics, Hsu-Nien Yang

Theses

A novel microelectromechanical actuator has been designed for moving an optical input fiber into alignment with one of three stationary output fibers. This switching device thus can connect an input optical port to one of 3 selected optical ports. The actuation force is created by a vertical-drive armature measuring 0.5x2.7 mm² mechanically tethered to the input optical fiber. A force of 2.33 mN is obtained from the linear acturator when the vertical stator armature gap is one micron and the applied three phase voltage is 140 Volts. The required force is a function of the input fiber length, e.g. …

Neural Net Classification Of States In Finite State Vector Quantization, Zhigang Zhang

Theses

In this thesis, a new image coding technique based on Neural Network Finite State Vector Quantization(NNFSVQ) is presented. The new design takes advantage of the high interblock spatial correlation of pixels in typical grey-level images, in addition to intrablock correlation already exploited by vector quantization (VQ). Although many FSVQ require large memory space for the storage of the numerous state codebooks, the memory space requirement of NNFSVQ can be reduced by a very large factor (about 10²-10³) to manageable size without impairing image quality. Simulation experiments have shown that by using NNFSVQ the bit rate can …

Recycling: Separation Of Major Thermoplastics From Postconsumer Plastics Stream, Rafael A. Rodriguez

Theses

The complete process for separating Low Density Polyethylene (LDPE), High Density Polyethylene (HDPE), Polyvinyl Chloride (PVC), Polypropylene (PP), Polystyrene (PS), Polyurethane (PU), and Polyethylene Terephthalate (PET) from a mixture of postconsumer plastics materials was presented. The driving forces considered to achieve separation were different densities and selective solubility of plastics in specific solvents.

The proposed process separates Polyurethane and Polystyrene by using aqueous solutions of different densities. On the other hand, the other five plastics are separated using solvents.

Diagrams showing streams and plastics separation in each unit were discussed. Individual material balances for each step were performed for a …

Implementation Of Parallel Sorting Algorithms On A Transputer Network, Venkatraman U. Calidas

Theses

Many sorting algorithms, such as the bubble sort and the binary tree selection sort, are n-squared algorithms and take O (n2) time to sort n values. These can be easily parallelized; the resulting sorts are called the odd-even transposition sort and the parallel tree selection sort, respectively. These have O(nlogn) time complexity. The quicksort is an O(nlogn) algorithm and it can parallelized to make it an O(logn) algorithm.

A transputer is a microprocessor which has serial links to transmit and receive data from other transputers. The above algorithms are implemented on a network of transputers and the link connections for …

The Interconnection Network Analysis Package, Nadeem Sabbar

Theses

This thesis focuses on the development of the Interconnection Network Analysis Package (INAP), and the use of INAP to analyze minimal permutation networks. The INAP code is written in C language using Turbo C compiler. Although the INAP has been used to analyze the subject networks it is not a dedicated system. It gives the user the freedom to create the permutation network from scratch (1-8 inputs and 1-7 stages), and then to process it for any number of stages.

The INAP made the analysis of five input networks easy and efficient. The networks have been analyzed stage by stage. …

Design And Simulation Of Submicron Microelectronic Vacuum Triodes, Hou-Jun Wang

Theses

This thesis presents the first design and detailed Simulation of submicron vacuum microelectronic triodes static characteristics. In this thesis a new 5-electrode active device is emphasized.

These devices have potentially important advantages over semiconductor devices. They can be used in extreme environments. The picosecond transit time for internal electron ballistics provide optimism for very fast devices applications. It appears reasonable to fabricate these devices using standard VLSI processing equipment. Further, the micron dimension makes " vacuum microelectronic chips" a reasonable goal.

Devices are characterized for static parameters including electron trajectories, electric field contours, and voltage potential contours. The field emission …

Monolithic Induction-Sourced Ac-To-Dc Power Supply Design, Jianhua Chen

Theses

This thesis describes techniques with design nomographs for supplying power to CMOS and microelectromechanical implanted devices. These applications require voltages in the range of 5 to 50 volts. Different kinds of voltage multiplier circuits were used to achieve high voltage output. The AC-to-DC and DC-to-DC capacitive bootstrap voltage multipliers are designed and analyzed. The AC-to-DC and DC-to-DC inductive bootstrap voltage multiplier circuits are presented and the SPICE simulations are done with those circuits. Four different options of inductive link high voltage power supply are presented, analyzed and compared. The link parameters of two VLSI-compatible square-shaped coils are calculated in both …

A Quantization Noise Feedback Technique In Pyramid Image Coding, Zhili Lin

Theses

In communication, we frequently encounter the problem about the trans-mission rate and quantization noise. That is, small quantization noise or high fidelity definitely increases transmission rate, or large quantization noise or low fidelity might require low transmission rate. In our research, we developed a quantization noise feedback technique, with which quantization noise can be reduced greatly at a given transmission rate. We applied this technique in pyramid image coding environment. An error analysis in frequency domain was carried out. Error estimation for pyramid image coding with and without quantization noise feedback was made. Finally, plenty of computer simulation confirms our …

Microcomputer-Based Visual Controller And Data Logger System, Xiao-Fang Qi

Theses

This thesis paper describes the firmware design, instead of the hardware logic design, makes the machine vision hardware system economical, intelligent and expandable. It shows the construction and testing of a novel remote low speed machine vision control system, which also has functions as data logger and is capable of auto control. The system has 9 analog input channels available, and more. It also has 4 digital output channels for controlling external devices. This work also implemented a way to transfer the grabbed image to a PC/XT. In the 256 graphics mode of the VGA, 64 B&W gray levels can …

Measurement Of Cluster Size By Retarding Potential And Time-Of- Flight Methods In An Ionized Cluster Beam Deposition System, Yung-Kuan Wang

Theses

The goal of this research was to study the mass distribution of ions generated in the Ionized Cluster Beam (ICB) deposition system. The ICB deposition method has been used to form high quality films of metals and other materials. It was postulated that the clusters consisting of hundreds and thousands of atoms produced by vapor expansion in the ICB source are responsible for the superior film properties. However, consistent experimental evidence concerning the cluster mass distribution, or even the existence of such clusters in the ICB apparatus, was lacking.

Two methods of cluster ion mass spectroscopy were used in this …

Max/Min : A Novel Rank Order Based Filter Family, Raafat E. Kamel

Theses

In the early development of signal and image processing, linear filters were the primary tools. Their mathematical simplicity made them easy to design and implement. They also offered satisfactory performance in many applications. However, they show poor performance in other cases, such as image processing.

Nonlinear filtering offered a solution to these problems. Nonlinear filtering has undergone a lot development for a long time. Among the first known nonlinear filters was the median filter, which was proposed by Tukey. Median filter preserves signal or image details better compared to a linear filter. Later other nonlinear filters were developed, including median …

Finite Element Analysis Of Thermal Stresses In Semiconductor Devices, Joachim Karl Wilhelm Duerr

Dissertations and Theses

The failure of integrated circuit due to Silicon fracture is one of the problems associated with the production of a semiconductor device. The thermal stresses, which result in die cracking, are for the most part induced during the cooling process after attaching the die with Gold-Silicon solder. Major factors for stress generation in material systems are commonly large temperature gradients and substantial difference in coefficients of thermal expansion.

This research covers the thermal stresses introduced upon cooling a composite Silicon device. A transient thermal analysis has been performed to determine the temperature gradients. The stress distribution has been investigated. For …

Comparative Analysis Of Single And Double Dwell Acquisition Schemes, Gurinder Singh Ahluwalia

Theses

Single and double dwell pseudonoise (PN) acquisition systems are described, explained and analyzed. These systems are designed to synchronize a locally generated PN signal with a received PN signal of unknown phase in the presence of noise. The mean, variance and an approximate probability distribution function (PDF) of the acquisition time for the single and double dwell PN acquisition schemes is developed. Intuitively, the double dwell acquisition system should be superior to the single dwell system because of the ability to quickly dismiss incorrect cells and further verify probable hits. It is shown analytically that this is in fact true …

Design Of A Microengineered Pressure Sensor, Ranjeet Alexis

Theses

A new family of microengineered vacuum ionization gauges of an approximate volume of 200µ³ has been designed. These devices can he fabricated using existing semiconductor processing capabilities. The focus of this thesis is to scale down the current state-of-the-art for ionization sensors to micron dimensions. These gauges can be manufactured economically and potentially will be integrated with more complex structures and circuitry. In these devices an active ionization volume of micron dimensions is used for launching ions in a trajectory towards a collection electrode. Ionization of gas species is accomplished by an electron flux of sufficient energy. Analysis of …

Improving The Throughput Of Plasticating Extruders : Measurement Of The Interparticulate Friction Coefficient For Polymeric Particulates With Circular And Profiled Cross Sections, Aiping Chen

Theses

This thesis deals with the coefficient of friction between individual polymeric pellets, the interparticulate friction coefficient (IPFC). It has been measured using a shear cell for a wide variety of circular and profiled cross?section pellets for a variery of polymeric materials. First, the thesis explains the reasons why it is desirable to enhance the IPFC based on the melting mechanisms in a single screw plasticating extruder. By making pellets with profiled cross?section pellets, the IPFC is greater than for pellets of circular cross?section. Second, it describes the test apparatus for measuring the IPFC and the method for calculating the IPFC. …

Hardware Algorithms For Computing Transcendental Functions, Xin-Pei Gong

Theses

The COordinate Rotation Digital Computer(CORDIC) is a special-purpose digital computer for real-time airborne computation. In this computer, a unique computing technique is employed which is especially suitable for solving the trigonometric relationships. A new computing technique based on the CORDIC algorithm is developed to reduce the number of iterations by one half for each input angle. This improvement is accomplished. by scanning multiple bits of the input angle(in our case, two) at a time. The CORDIC equations are rewritten accordingly and a hardware implementation structure is also presented. The results of the software simulation of the new algorithm are as …

Decomposing Non-Product Form Queuing Lattices Through Genetic Algorithm, Wei Han

Theses

In this paper, a Genetic Algorithm technique is adapted to decompose the state transition lattice of a class of non-product form queueing models. Genetic Algorithms are search algorithms based upon the mechanics of natural genetics. They combine a survival-of-the-fittest among string structures with a structured, yet randomized, information exchange to form a search algorithm with some of the innovative flair of human search. While randomized, genetic algorithms are no simple random walk. They efficiently exploit historical information to speculate on new search points with improved performance. Here genetic algorithms is applied to a non-product queueing lattices optimization problem. Only the …

Conditional Artificial Dielectric Waveguide, Hsien-Wen Ho

Theses

A thin layer of semiconductor ( the guest material ) is sandwiched between two polymeric films ( the host material ) to form an artificial dielectric waveguide. An artificial dielectric is a composite material consisting of a dielectric with a large number of conducting particles arranged in a three-dimensional pattern. The particle dimensions are smaller than the optical wavelength of interest. A beam of light with a photon energy above the band-gap of the semiconductor ( pump light ) induces electric and magnetic dipoles which affect the propagation of light with a photon energy below the band-gap ( probe light …

Point Pattern Matching By A Genetic Algroithm, Minghwang Chen

Theses

The problem we consider is to find a subset of points in a pattern that best match to a subset of points in another pattern through a transformation in a least squares sense. Exhaustive search to find the best assignment mapping one set of points to another set is, if the number of points that are to be matched is large, computationally expensive. We develop a genetic algorithm which searches for the best ("almost the best") assignment efficiently. To map the point pattern matching into the framework of a genetic algorithm, we use a fitness function which inversely proportional to …

Performance Evaluation Of Consumer Electronic Bus, Sairaj R. Pakkam

Theses

This thesis describes the performance evaluation of the Consumer Electronic Bus proposed by the Electronic Industries Association. To study the behaviour of CEBUS under different traffic conditions, a simulation program was developed modelling the layer architecture of CEBUS. The CEBUS is based on the ISO/OSI model of layered architecture. The simulation results have shown that, when the throughput of the network is small, the delay is bounded for all messages of all priorities. As the throughput of the network increases, under the presence of more high priority messages, the lower priority messages get queued at their nodes. It is also …

A Critical Analysis On Cogeneration Policy, R. Tjahjokartiko Gondokusumo

Theses

It could be difficult to understand electricity problems without knowing its history; how a combine of legal, administration, and financial means effects electricity in the development. The recent public law on energy-related issues traceable by this study is the Renewable Energy and Energy Efficiency Technology Competitiveness Act of 1989.

In short, cogeneration was proposed to utility (as public property) from industry (as private property) under PURPA (of which National Energy Act is the legislative history). Thus, it should be clear that the problems of cogeneration is not pro or contra issues. It is a national issue. Then, a cogeneration planner …

Density Currents In Circular Wastewater Treatment Tanks, David M. Laliberte

Dissertations and Theses

Deviations from ideal flow and settling occur in circular wastewater treatment tanks because of tank geometry, flow conditions, and density currents caused by variations in suspended solids concentration and temperature distributions. Thermally induced density currents were investigated in this study. Under winter, low flow conditions, measurements were made of vertical and radial temperature distributions in the circular chlorination tank at Lake Oswego, Or., and in the circular primary and secondary clarifiers at Bend, Or. Thermistor arrays were used to collect the data which exhibited both vertically well-mixed and a two-layer flow regime. Inlet geometry and suspended solids in the secondary …

Gis Address-Matching And Transportation Analysis, James D. Orrell

Dissertations and Theses

Geographic Information System (GIS) address-matching combined with other GIS processing offers new analytical opportunities in the area of transportation planning and analysis. Address-matching, an automated method for generating geographically-referenced (geocoded) point locations on a map from common tabular databases, can facilitate transportation analysis by providing a planning tool based on individual rather than aggregated spatial distributions more common to transportation issues.

This thesis presents a case study in which GIS address-matching was I applied to a transportation problem at Oregon Health Sciences University (OHSU) in Portland, Oregon. The transportation problem at OHSU is common to major employment centers in urban …

Condensed Silica Fume Concrete, Mohamed Nagib Abou Zaid

Archived Theses and Dissertations

No abstract provided.

The Development And Application Of A Trapezoidal Shear Panel For Use In Finite Element Codes, Glenn P. Greiner

Master's Theses - Daytona Beach

This thesis documents the efforts of the writer and his colleagues over the past several years to improve the theoretical foundation of the arbitrary quadrilateral shear panel used in structural analysis codes to model aircraft structures. An equilibrium stress-based element with pure shear resultants on its sides was developed using the principle of complementary virtual work. The internal stress field was derived from a complete polynomial Airy stress function. The element was numerically tested as a pure stress element and a hybrid element to assess the deflection properties for highly distorted planar panels. Linear-stress and quadratic-displacement rods were used, as …

Usair: Balancing Terminal Facilities And Runway Capacity At Pittsburgh, Edward J. Mattern

Master's Theses - Daytona Beach

As a result of expansion and acquisition, USAir has experienced major growth in flight operations. In an effort to accommodate this expansion, a major construction project, called the Midfield Terminal project, is underway at USAir's major hub, Greater Pittsburgh International Airport (PIT). The Midfield Terminal will result in a 60 percent increase in gate capacity for USAir and lower operating costs due to its location. However, increased gates infer increased flight frequencies. PIT already operates near capacity during peak periods and runway expansion has only been discussed. This paper evaluates the conditions of USAir at PIT with regard to the …

A Comparative Study Of Spectral Peaks Versus Global Spectral Shape As Invariant Acoustic Cues For Vowels, Amir Jalali Jagharghi

Electrical & Computer Engineering Theses & Dissertations

The primary objective of this study was to compare two sets of vowel spectral features, formants and global spectral shape parameters, as invariant acoustic cues to vowel identity. Both automatic vowel recognition experiments and perceptual experiments were performed to evaluate these two feature sets. First, these features were compared using the static spectrum sampled in the middle of each steady-state vowel versus features based on dynamic spectra. Second, the role of dynamic and contextual information was investigated in terms of improvements in automatic vowel classification rates. Third, several speaker normalizing methods were examined for each of the feature sets. Finally, …

Navier-Stokes Simulations Of Flows About Complex Configurations Using Domain Decomposition Techniques, Kamran Fouladi-Semnani

Mechanical & Aerospace Engineering Theses & Dissertations

An algorithm is developed to obtain numerical simulations of flows about complex configurations composed of multiple and nonsimilar components with arbitrary geometries. The algorithm uses a hybridization of the domain decomposition techniques for grid generation and to reduce the computer memory requirement. Three dimensional, Reynolds-averaged, unsteady, compressible, and complete Navier-Stokes equations are solved on each of the subdomains by a fully-vectorized, finite-volume, upwind-biased, approximately-factored, and multigrid method. The effect of Reynolds stresses is incorporated through an algebraic turbulence model with several modifications for interference flows. The present algorithm combines the advantages of an efficient, geometrically conservative, minimally and automatically dissipative …