Engineering Commons^™

Tantalum Silicide Variable Capacitance Rotary Micromotors : Design And Fabrication, Michael Steven Berry

Theses

Tantalum silicide was studied as an alternative microelectromechanical material by fabricating a rotary micromotor utilizing a proven design. This material was used for the rotor, stators, and bearing over a silicon substrate. It has the attraction of potentially reducing the friction which is a major problem with polysilicon-to-polysilicon bearings.

The necessity of high aspect ratio features required that a plasma or reactive ion etch with a high degree of anisotropy be developed to etch tantalum silicide films in excess of 1.5μm. A sulfur hexafluoride/Freon 115 plasma provided the necessary process control during the etches. The stress present in annealed tantalum …

Aluminum Epitaxy On Silicon, Samuel Cruz Ramac

Theses

The purpose of this work was to study the effect of 4° miscut and chem¬ical pretreatment of Si(111) wafers on the epitaxial growth of Al by thermal evaporation in a UHV environment (~ 10^-9 Torr). Two chemical pretreatments of the wafers were used. One included HF only and the other included NH₄F after an initial HF treatment. The substrates were not heated dur¬ing deposition. XRD measurements of the films were done before and after annealing in a high vacuum oven for one hour at temperatures between 200 and 350°C.

The A1(200) films deposited on wafers pretreated with …

Simulation Of Manufacturing Cell Using Hoops Graphic Software And Siman Simulation Language, Parikh Vipul

Theses

Control of jobs being processed in manufacturing shop floor is important to management. The performance of job shop is affected by shop congestion due to arrival rate, batch size, number of machines, buffer capacity, process time variation, and dispatching rules use to load the jobs on the machine.

The job shop is a very complex system and hence, it is difficult as well as time consuming to obtained result using analytical method. A SIMAN simulation language is used to create generic model of a manufacturing cell and simulation analysis of those parameters variation such as job shop efficiency, the average …

Blur Identification And Restoration Of Images Of Coronary Microvessel, Kuen Tak Wong

Theses

The objective of this research was to identify the blur characteristics of the blurred images of the rat coronary microvessel, and the information of the blur characteristics was used to restore the blurred images. The blur characteristics were analyzed by using the image power cepstrum. The Wiener filter was implemented to restore the images. There were two types of point spread functions proposed and studied for the restoration. They were: defocus blur PSF and motion blur PSF. The images were transferred from HP A900 system to an AVS workstation. The images were processed and manipulated by the AVS, and showed …

Improving The Jitter Performance Of Timing Recovery By Employing Delay Shifts, Xin De Lu

Theses

Many methods have been developed for evaluating the jitter performance of timing recovery circuits for binary synchronous transmission systems. These circuits consist of a nonlinear device followed by a narrowband filter tuned to the pulse repetition frequency. This thesis introduce delay shifts in the timing recovery circuits to improve the jitter performance. The function of the delay shifts is analyzed and mathematical proof of jitter performance improvement is given for the system using square-law device. Finally, the numerical results obtained from the specific examples serve to illustrate the significant improvement between the system with and without delay shifts. That is, …

Investigation Of The Effects Of Methyl Chloride Addition On Premixed, Laminar, Methane/Air Flat Flames, Limin Wang

Theses

Temperatures and the concentrations of stable species, such as CO, CO₂, CH₄, and CH3Cl, have been measured over the height above burner at equivalence ratio of 0.79 (fuel lean) and 1.20 (fuel rich) for premixed, laminar CH₄/air and CH₃Cl/CH₄/air flat flames. A water-cooled quartz sampling micro-probe and gas chromatographic analysis were used for the concentration measurements. Chemical kinetic modeling of these flames with a 279-reaction, 63-species elementary reaction mechanism is performed using the CHEMKIN premixed flat flame code. The results of rate-of-production calculations are analyzed to determine the most important …

Modeling And Simulation Of Magnetic Micromotor Performance, Ping Wang

Theses

The objective of this research was to model the performance and optimize geometries for two types of magnetic micromotors: yoke-type (YTMM) and yokeless (YSMM). The two selected micromotor types matched the designs that have been described in the recent research literature. Modeling was accomplished using MAXWELL, an advanced 2-D and 3-D simulator. The micromotors with nickel and nickel-iron magnetic thin films for the rotor and stator were simulated for torque performance. Three-phase power supplies with overlapping and non-overlapping phases were used. Rotor diameter dimensions were varied from 285 to 600µm, and the rotor-stator air gap was varied from 3 to …

Modeling And Analysis Of Semiconductor Manufacturing Processes Using Petri Nets, Xinyao Wang

Theses

This thesis addresses the issues in modeling and analysis of multichip module (MCM) manufacturing processes using Petri nets. Building such graphical and mathematical models is a crucial step to understand MCM technologies and to enhance their application scope.

In this thesis, the application of Petri nets is presented with top-down and bottom-up approaches. The theory of Petri nets is summarized with its basic notations and properties at first. After that, the capability of calculating and analyzing Petri nets with deterministic timing information is extended to meet the requirements of the MCM models. Then, using top-down refining and system decomposition, MCM …

Modeling And Investigation Of Current Transport Phenomena In Schottky Structures, Yan Zeng

Theses

We have used a numerical method to describe the importance of the contribution of generation-recombination current to the I-V characteristics of Schottky barrier contacts. The current-voltage relationship is derived directly from the fundamental set of equations such as Poisson; current-density and continuity equations, without having to make many simplifications or approximations. The final result includes not only the thermionic emission or drift diffusion mechanisms of current flow, but also the generation recombination processes.

The experimental devices used for this work are very common low barrier height Schottky structures, Al/T_0.3W_0.7/n-Si/A1 and Ti_0.3W_0.7/n-Si/Al. The …

Study Of Emg Frequency Behavior, Mark Steven Fiedorowicz

Theses

It has previously been determined that the power spectral density of an electromyogram shifts towards lower frequencies over time during an isometric contraction. In this study the power spectral density curve was examined to see if changes would occur over a period of time as a subject walked on a treadmill at various speeds. The shapes of the power spectral densities recorded from the soleus shifted to the lower frequencies over time. The parameters associated with the curves showed trends. One of the parameters, zero crossing, demonstrated adaptation and fatigue in all four patients, for the first portion of the …

An Experimental Investigation Of Wear Behavior Of Ultra-High Molecular Weight Polyethylene Under Sliding Motion, Elham Zand-Moghaddam

Theses

This project investigates the effect of sliding motion on the materials that are used as bearing surfaces of human total-joint replacement prostheses.

The tests are performed with a specially designed equipment based on pin-on-disk machine. The testing machine is designed and constructed to reproduce sliding motion, applied to spherical ended metal "Canine-Head" components such as dog hip acting on a flat polyethylene surface. The sliding motion is performed by applying different constant loads for 5,000,000 cycles. The tests are carried out with the wear specimen lubricated by deionized water.

The purpose is to produce delamination, which is the severe wear …

Mechanism Of Pneumatic Fracturing, Trevor Compton King

Theses

This thesis investigates the mechanism of pneumatic fracturing in geologic materials such as soil and rock. Pneumatic fracturing is a recently developed technique for increasing the permeability of geologic formations by the controlled injection of high pressure air. Present applications are focusing on the in situ remediation of contaminated soil and ground water, although pneumatic fracturing has other geotechnical uses such as pumping well enhancement.

A comprehensive literature review of a related technology known as hydraulic fracturing is presented, which serves as background for development of a pneumatic fracturing model. Pressure-time histories from actual pneumatic injections are analyzed in detail …

Integration Of Pneumatic Fracturing To Enhance In Situ Bioremediation, Conan Dante Fitzgerald

Theses

The purpose of this thesis was to study the anticipated benefits of integrating pneumatic fracturing with in situ bioremediation. Since pneumatic fracturing increases subsurface air flow in low permeability formations, it has the potential to overcome many of the major limiting factors of microbial growth and activity. A new innovation called pneumatic bio-injection can further enhance in situ bioremediation by efficiently dispersing biological solutions, including microorganisms, into a formation.

Bench scale experiments were conducted to examine the ability of microorganisms to survive the pressures and stresses associated with pneumatic injection. Tests conducted at pressures ranging from 60 to 500 psi …

A Multicompartmental Model For The Simulation Of Soluble Gas Exchange In The Lungs, Chitaranjan Varadhan

Theses

No abstract provided.

Detection And Location Of Pipe Damage By Artificial-Neural-Netprocessed Moire Error Maps, Barry G. Grossman, Frank S. Gonzalez, Joel H. Blatt, Scott Christian Cahall

Electrical Engineering and Computer Science Faculty Publications

A novel automated inspection technique to recognize, locate, and quantify damage is developed. This technique is based on two already existing technologies: video moire metrology and artificial neural networks. Contour maps generated by video moire techniques provide an accurate description of surface structure that can then be automated by means of neutral networks. Artificial neural networks offer an attractive solution to the automated interpretation problem because they can generalize from the learned samples and provide an intelligent response for similar patterns having missing or noisy data. Two dimensional video moire images of pipes with dents of different depths, at several …

Cone Penetration In Cemented Deposits-A Field Study, Semih Arslan

LSU Historical Dissertations and Theses

Neglecting cementation results in an underestimation of slope stability and pile capacity in design and analysis of geotechnical engineering problems related to cemented deposits. Developing methods to identify and assess the engineering characteristics of cemented deposits is an important subject in geotechnical engineering.

This study is conducted to evaluate the reliability of the prediction schemes proposed by previous investigators through a field study of cone penetration in a cemented deposit and respective laboratory triaxial study on undisturbed cemented specimens. The effect of cementation on cone penetration resistance is investigated through the field study, and the effects of cementation on drained …

Light-Emitting Diodes From Partially Conjugated Poly(P-Phenylene Vinylene), C. Zhang, David Braun, A. J. Heeger

Electrical Engineering

We report the effect of conversion conditions on the device characteristics of poly(p-phenylene vinylene) (PPV) light-emitting diodes. Both electroluminescence and photoluminescence intensities decrease with increasing degree of conversion. Partial conjugation enhances the electroluminescence intensity and gives an efficiency (with Ca as electron-injecting contact) as high as 0.75% photons per electron, about two orders of magnitude more efficient than from similar devices prepared from fully converted PPV. The results of constant current stress measurements suggest that the partially conjugated PPV diode is relatively stable at room temperature.

Effects Of Crosstalk On Fidelity In Page-Oriented Volume Holographic Optical Data Storage, Gregory P. Nordin, P. Asthana

Faculty Publications

Using numerical simulation, we quantitatively examine the effects of cross talk on the recall fidelity of stored binary data in a page-oriented volume holographic memory system. We discuss the trade-off between the signal-to-noise ratio of the reconstructed bits and the optical throughput of the system (i.e., the fraction of the incident beam that is diffracted to the detector plane). We show that significant gains in the signal-to-noise ratio can be achieved with modest decreases in optical throughput in the region where the highest throughput occurs. The magnitude of this trade-off is influenced by both beam degeneracy and coherent recording cross …

Gravity Sedimentation: A One-Dimensional Numerical Model, Joanna Robin Karl

Dissertations and Theses

A large fraction of the current cost of wastewater treatment is from the treatment and disposal of wastewater sludge. Improved design, energy efficiency, and performance of dewatering facilities could significantly decrease transport and disposal costs.

Dewatering facilities are designed based on field experience, trial and error, pilot plant testing, and/or full scale testing. Design is generally time-consuming and expensive. A full-scale test typically consists of side-by-side operation of 4 to 5 full-scale dewatering units for several weeks to more than 6 months. Theoretical modeling of the physics of dewatering units such as the belt filter press, based on laboratory determined …

Designing And Simulating A Multistage Sampling Rate Conversion System Using A Set Of Pc Programs, David Joesph Hagerty

Dissertations and Theses

The thesis covers a series of PC programs that we have written that will enable users to easily design FIR linear phase lowpass digital filters and multistage sampling rate conversion systems. The first program is a rewrite of the McClellanParks computer program with some slight modifications. The second program uses an algorithm proposed by Rabiner that determines the length of a lowpass digital filter. Rabiner used a formula proposed by Herrmann et al. to initially estimate the filter length in his algorithm. The formula, however, assumes unity gain. We present a modification to the formula so that the gain of …

Designing And Simulating A Multistage Sampling Rate Conversion System Using A Set Of Pc Programs, David Joseph Hagerty

Dissertations and Theses

The thesis covers a series of PC programs that we have written that will enable users to easily design FIR linear phase lowpass digital filters and multistage sampling rate conversion systems. The first program is a rewrite of the McClellan-Parks computer program with some slight modifications. The second program uses an algorithm proposed by Rabiner that determines the length of a lowpass digital filter. Rabiner used a formula proposed by Herrmann et al. to initially estimate the filter length in his algorithm. The formula, however, assumes unity gain. We present a modification to the formula so that the gain of …

Quasi-Static Deflection Compensation Control Of Flexible Manipulator, Jingbin Feng

Dissertations and Theses

The growing need in industrial applications of high-performance robots has led to designs of lightweight robot arms. However the light-weight robot arm introduces accuracy and vibration problems. The classical robot design and control method based on the rigid body assumption is no longer satisfactory for the light-weight manipulators. The effects of flexibility of light-weight manipulators have been an active research area in recent years. A new approach to correct the quasi-static position and orientation error of the end-effector of a manipulator with flexible links is studied in this project. In this approach, strain gages are used to monitor the elastic …

Inhibition Of Surface-Related Electrical Breakdown Of Long P+-I-N+ Silicon Structures, F. E. Peterkin, P. F. Williams, B. J. Hankla, L. L. Buresh, S. A. Woodward

P. F. (Paul Frazer) Williams Publications

Semiconductors such as silicon and GaAs appear attractive for use in high voltage devices because of their high bulk dielectric strength. Typically, however, such devices fail at a voltage well below that expected due to a poorly understood, surface-related breakdown process. In this letter we present empirical results which show that such breakdown of long silicon p⁺-i-n⁺ devices can be inhibited by the application of weak visible or near-infrared illumination. These results suggest a technique for avoiding surface flashover in practical high voltage devices, and provide information about the physical mechanisms responsible for initiating …

Distributed Economic Systems With Agents That Learn, Stanley Foster Perry

Dissertations and Theses

Economic systems are distributed in the sense that economic agents make decisions without any central control. Prices, quantities, wealth, and market structure emerge from the interaction of agents acting in their own self interest. The concepts and language of systems science are used to define economic systems in a manner that captures and articulates the distributed nature of economic systems. Further, the systems definition permits multiple views of the economic system, and in addition, allows the agents to "step outside" the system in order to study it.

Economic systems are defined in such a way that it is feasible to …

Measurement Of The Nonsteady Flow Field In The Opening Of A Resonating Cavity Excited By Grazing Flow, Hans R. Graf, William W. Durgin

Office of the Provost Scholarship

Flow past the opening of a cavity can excite acoustic resonance. The periodic velocity field in the region of the cavity opening has been measured for various flow conditions and the vorticity distribution has been computed from the measured data using numerical differentiation. The results indicate that the shear layer rolls up into discreet vortices, which travel across the cavity opening. Two resonances were found. The first is characterized by a single vortex being present and results in the greatest amplitude. The second is characterized by the presence of two vortices which excite a distinct but lesser amplitude resonance. As …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 9, Number 5, May 1993, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Acuta Enews May 1993, Vol. 22, No. 5

ACUTA Newsletters

In This Issue

Call for Nominations page 2

President's Message page 3

MHEC $aves with Virtual Private Network page 4

Board of Directors Meeting page 5

Tireed Dues page 5

Toll Fraud Takes Aim page 6

Infrastructure page 7

Toll Fraud Checklist page 8

Will My Cellular Phone Fry My Brain? page 9

Executive Director's Message page 11

Third International Conference On Case Histories In Geotechnical Engineering, Multiple Authors

International Conference on Case Histories in Geotechnical Engineering

No abstract provided.

Analysis Of Laser Pulse Chirping In Mode-Locked Vertical-Cavity Surface-Emitting Lasers, Wenbin Jiang, Dennis J. Derickson, John E. Bowers

Electrical Engineering

Mode-locked vertical cavity lasers have a large cross-sectional area and consequently a large saturation energy and large peak powers. The authors analyze excess optical bandwidth generation in these lasers and find that self-phase modulation due to optical pumping and gain saturation is the dominant factor in inducing laser pulse chirping. The large magnitude of the chirp makes intracavity prism-pair compensation difficult. Adjustment of the cavity length has a major impact on the pulse chirping, as observed experimentally. Proper adjustment can result in a large linear frequency chirp which can be compensated using external pulse compression techniques

Bulletin No 4242 - The Lyre Trellis For Viticulture, Alain Carbonneau Dr, Vincent P. Desplat, John F. Elliott, Peter Watt

Bulletins 4000 -

The lyre vine training system uses wide rows, an open canopy, and shoot positioning to increase grape maturity and quality while maintaining production levels. It is so named because the end-on view of the vine canopy trained to this type of trellis resembles the shape of the musical instrument, the lyre.

This improvement in quality has not only been established in the diverse experimental vineyards of the National Institute for Agronomic Research (INRA) in France but also in many commercial vineyards throughout the major wine growing regions of the world.