Engineering Commons^™

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 …

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 …

Fair And Efficient Transmission Over Gbps Dual Ring Networks, Abdelnaser M. Adas

Theses

The advances in fiber optics technology provide large bandwidth and enable the support of a wide variety of services. New network architectures have been proposed, such as Metaring and Distributed Queue Dual Bus (DQDB), that try to take advantage of the new capabilities. Because of the very small packet transmission time relative to the feedback time a challenging issue in high speed networks is the efficient and fair share of the channel bandwidth among the competing users. In this thesis we first investigate and compare the performance of the Global and Local Fairness Mechanisms (GFM and LFM, respectively). They have …

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 …

Geometric Dimensioning And Tolerancing A Tool For Concurrent Engineering, Tapan Kumar S. K. Jain

Theses

The concept of Concurrent Engineering recognizes an immediate need for a new design environment and technology and so requires extensive interdisciplinary cooperation and integration of diverse functions of a manufacturing organization such as marketing, design, manufacturing and finance. One of the key factors to achieve successful integration among the departments is better communication and it becomes imperative in cases of varying levels of communication needs, especially in interdepartmental cases.

Concurrent Engineering is a philosophy which provides certain benefits. There are various tools and methods available for implementation of Concurrent Engineering concepts. One of the tools is Geometric Dimensioning & Tolerancing …

Performance Of Different Strategies For Error Detection And Correction In Arithmetic Encoding, George F. Elmasry

Theses

Lossless source encoding is occasionally used in some data compression applications. One of these encoding schemes is the arithmetic encoding.

When data is to be transmitted via communication channel, noise and impurities imposed by the channel cause errors. To reduce the effect of errors, channel encoder is added prior to transmission through the channel. Channel encoder inserts some bits that help channel decoder at the receiver end to detect and correct errors. These added error detection and correction bits are redundancy that causes reduction in the compression ratio and hence an increase in data rate through the channel. The higher …

A Simulation Of A Monitoring And Alarm System In An Energy Management System, Hui-Jen Liu

Theses

This is a simulation for an energy system's monitoring and alarm and working under KEE's environment. Because of KEE's powerful capabilities, we can monitor and get warning signals from several active windows that we attaching them from KEE's system knowledge base to our source code.

It is very convenient for us to set every member of the energy system on an image panel. We can monitor the entire conditions of that member and get highlighted warning signals from its own image panel. Also we can initialize them by a kind of method-actuators windows if we want to restore the system.

Design Of A 320x122 Mwir-Ccd Ptsi-Si Imaging Radiometer With Automatic Optical Integration Time Control, Nathaniel Joseph Mccaffrey

Theses

An infrared CCD camera system was designed and developed to operate a 320X244 Schottky-barrier IR-CCD Focal Plane Array (FPA) as an imaging radiometer. The goal of this research was to develop a reliable radiometer capable of resolving temperatures between 50 and 1000°C to within 1°C accuracy using non-contact spectral thermographic methods. To accomodate this wide dynamic range, the imager was operated in a non-interlaced format with variable optical integration times ranging from 120µsec to 122msec. Variable integration control was achieved by employing a "dump and read" timing procedure. To facilitate this operation, novel circuitry was developed for dynamically controlling the …

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 …

Multilevel Embeddings For Massively-Parallel Hypercubes, Devenkuma P. Shah

Theses

Hierarchically structured arrays of processors have widely been used in the low and intermediate phases of image processing and computer vision. Since the pyramid structure efficiently supports local and global operations extensively required by these phases, it has been widely used for relevant algorithms. Multilevel systems keep all the advantages of the pyramid structure while providing a general hierarchical structure that is easier to be used for the development of several algorithms and may also provide higher performance.

Although the cost of pyramid machines may be tremendously high, they have limited applications. In contrast, the hypercube network is widely used …

Computer Simulation Of Intracranial Hemodynamics During The Induction Phase Of Anesthesia, Gopinath P. Sundaram

Theses

The induction of general anesthesia is associated with severe hemodynamic compromises which, in turn, may cause acute elevation of intracranial pressure (ICP). Quantitative assessment of cerebrovascular responses arising from multiple mechanical and pharmacological interventions occurring in a short time interval require a large number of human studies which are difficult to perform. The purpose of this project is to evaluate the effect of various stimuli on the intracranial hemodynamics during induction using a mathematical model of cerebrovascular circulation.

A five compartmental model of the cerebrovascular system is used for our simulation. Autoregulation is modeled by adjusting arterial-arteriolar resistance in order …

Fracture Of Cementitious Composites, Sira Tindukasiri

Theses

Studies in fracture mechanics of concrete use a testing setup which tends to include unacceptably large errors in deflection measurements. Recent work reported by Kim [3] has proposed a new testing setup to eliminate these errors and consequently produce better determinations of fracture parameters.

The error which occurs most frequently is in the measurement of the load-line deflection. Until recently, the way this measurement has been made, using a dial gauge or LVDT (Linear Variable Differential Transformer) to measure the deformation between the center of the specimen and the frame, includes the crushing of the concrete surface at the supports …

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 …

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 …

Design And Development Of Flexible Manufacturing Cells - A Case Study, Behrouz Barzani

Theses

This paper covers the typical ills of American manufacturing companies and provides steps to selecting a flexible manufacturing cell(s) or system as a remedy. For that reason various definition of different types of flexibilities in manufacturing and the interrelationships between the several types have been examined. In addition, their purposes, means of obtaining them and some measurement and evaluations has been discussed. This was done to cover the basic but necessary requirements for understanding and selecting a flexible manufacturing system. Finally, the design process of a flexible system and its intuitive justification were discussed.

Monolithic Silicon Opto-Electro-Mechanical Light Modulator, Ching-Horng Wu

Theses

A Fabry-Perot light beam modulator of the reflection-type has been designed with process and performance parameters optimized. This design takes advantage of the economies of surface micromaching using silicon substrates and selected thin films. High performance with a low drive voltage are achieved using electrostatic actuation of a thin polysilicon diaphragm. The diaphragm is a novel corrugated structure which has maximum compliance and maintains planarity during actuation. In addition, the corrugationsuspension used provides an improved linearity of amplitude modulation response as a function of the actuation voltage.

A preliminary version of this device has been fabricated through a contract foundry …

Analysis Of The Optimum Extraction System Design For The Separation And Purification Of Rare Earths, Kenneth Yeon-Kang Chan

Dissertations

A mathematical model for the liquid-liquid equilibrium of the lanthanide and yttrium oxides in the nitric acid - water - tributyl phosphate (HNO₃-H₂O-TBP) two-phase system has been developed. This model is based on the interrelationships of chemical reactions, phase equilibrium, and material balance. The chemical reactions were modelled using experimentally derived empirical equations for components involved. The distribution coefficients of 16 rare earths which were experimentally determined. by UK Harwell Laboratory were used to evaluate the parameters of this equilibrium model. Once model parameters are determined, material balance for all species in the HNO₃-H …

Analysis Of A Band-Saw, Suat Ali Ozsoylu

Dissertations

The solution for the transverse oscillations of a band-saw is determined. Two different models are treated: a fourth-order model and a second-order model. The response characteristics for both models are determined using Laplace transformation. To obtain the inverse Laplace Transform for the fourth-order model, it was necessary to fmd the frequencies by applying the Extended Lanczos Method in order to overcome the problem for computer overflow.

The limits of stability for both models are studied by plotting the eigenvalues against changing parameter values. Conditions for the onset of divergence and flutter instabilities, which need to be taken into account in …

Kinematic Synthesis Of Adjustable Four-Bar Mechanisms For Multi-Phase Motion Generation, Shao Jie Wang

Dissertations

A four-bar linkage can satisfy up to five prescribed positions for the motion generation problem. The adjustable four-bar linkage, on the other hand, can satisfy more than five given positions by making some of the parameters adjustable.

Limited work had been done in the area of motion generation problems of kinematic synthesis of adjustable four-bar linkages until Wilhelm introduced the concept of multiple adjustments.

This study considers for the first time, the adjustment of a moving pivot, and the problems of three phases of motion. Various combinations of the number of prescribed positions for the motion generation problems are solved …

Study Of Surface Properties Produced By Magneto-Plasma On Nitriding For Improving Wear Resistance, I-Tsung Shih

Dissertations

In this work a newly developed surface treatment process, Magneto-Plasma Ion Nitriding process, was developed and studied. This process was developed to increase durability and wear resistance of operational surfaces of different machine components.

In this study, orthogonal experimental analysis was used to develop, optimize, and select the process parameters. Coating layers were characterized and studied by using scanning electron microscopy(SEM), Auger electron spectroscopy(AES), and image analysis system. The influence of different process treatment parameters, such as temperature, nitrogen concentration, and magnetization, on the layers properties was studied. The mechanism of layer formation and bonding was proposed and a mathematical …

Investigation Of The Striation Formation In The Course Of Abrasive Waterjet Cutting, Jo-Fei Chao

Dissertations

The principal defect of the surfaces generated by abrasive waterjet machining is excessive waviness (striation). The existing theories of striation formation are not adequate to explain this phenomenon. The presented study is concerned with the development of an understanding of the mechanism of striation formation.

A spectral analysis of temporal process and spatial surface characteristics demonstrated that the striation is caused by nozzle vibration that is due to the conditions of the motion control of the nozzle. This enabled us to discover a means for improving the surface finish. From a study of the surface spectra, it was found that …

Investigation Of The Consumer Electronics Bus, Jaesoo Yang

Dissertations

The objectives of this dissertation are to investigate the performance of the Consumer Electronics Bus (CEBus) and to develop a theoretical formulation of the Carrier Sense Multiple Access with Contention Detection and Contention Resolution (CSMA/CDCR) with three priority classes protocol utilized by the CEBus

A new priority channel assigned multiple access with embedded priority resolution (PAMA/PR) theoretical model is formulated. It incorporates the main features of the CEBus with three priority classes. The analytical results for throughput and delay obtained by this formulation were compared to simulation experiments. A close agreement has been found thus validated both theory and simulation …

On Adaptive Censored Cfar Detection, Loizos Anastasiou Prastitis

Dissertations

In an automatic radar detection system the received signal in every range resolution cell is compared with a threshold to test for the presence of a target. A Neyman-Pearson type test is used which maximizes the probability of detection for a fixed probability of false alarm. For the simple case where the noise is homogeneous a fixed threshold is chosen to achieve the designed constant false alarm rate (CFAR). In the more realistic case the noise background is non-stationary due to clutter and interference. In this situation, the threshold used for testing a particular cell is usually set adaptively using …

Investigation Of Reactor Design Parameters Towards Optimizing Biodegradation Of Chlorophenols By Phanerochaete Chrysosporium, Nirupam Pal

Dissertations

The biodegradation of 2,4,6-trichlorophenol (246-TCP) and 2,4,5-trichiorophenol (245-TCP) by Phanerochaete chrysosporium was studied in batch and in continuous systems. Contrary to most of the previous reports from the literature, this study shows that degradation of both TCPs can occur in the absence of any measurable ligninase activity. The microorganism did not retain its degradative ability for more than about two weeks

In order to better understand the degradation process, the individual contributions of both the biomass and the extracellular proteins were studied separately. The results show that neither the biomass nor the extracellular proteins alone can completely degrade 246-TCP, but …

Computer Aided Manufacturing For Production Environment, Biren K. Parikh

Theses

Investments in new technology like Computer Aided Manufacturing (CAM) increased in the past few years because of the foreign competition in the world market as well as on the home ground. Improper investment in CAM and CIM resulted in the "Islands of Automation" instead of an integrated system. These "Islands of Automation" have created new problems for production planning and factory communication.

The objective of the thesis is to develop the methodology to selection and implementation of the CAM system in the production environment. It is to be noted that a CAM system is part of the overall CIM implementation, …

An Improved Human Gait Model Incorporating The Effects Of Muscle Activity And Joint Friction, Tae Ho Choi

Theses

In designing an artificial leg for an amputee, it is important to find those underlying principles which determine the normal human gait. For this purpose we have developed a model of human walking, in which it is possible to predict an optimal gait at any given speed of walking based on the principle of minimum mechanical energy consumption.

Our model is an extension of the model proposed by Mochon and McMahon (1980). Their model assumes that during the swing phase of walking mechanical energy is conserved. Non-conservative forces due to muscle activity are assumed to occur during the double support …

The Permeability Of Hot Mix Asphalt Concrete With Petroleum Contaminated Soils, Kuen-Yuan Chuang

Theses

It is estimated by the United States Environmental Protection Agency (USEPA) that there are 2 to 3.5 million underground storage tanks (USTs) throughout the nation and about 25% of these tanks are leaking. The leakage of petroleum or other organic material presents serious environmental problem due to the uncontrolled release of petroleum products to ground water. Many new techniques have developed to reuse these petroleum contaminated soils generated from sites containing leaking USTs. One such soil reuse method available since 1985 is the use of petroleum contaminated soils in the production of hot mix asphalt.

The stability, durability, and hydraulic …

Dynamics Of Blood Coagulation, Jie Gao

Theses

In this paper we present a new method to analyze whole blood coagulation dynamics. Using a PC-286 computer equipped with a DASH-16 AID board.

The row data from a SONOCLOT analyzer is amplified and digitized on the DASH-16 A/D board and stored in the PC-286 hard disk. The data is filtered through a digital Butterworth filter. The filtered data is then fit to mathematical relationship by the least square method. The coefficients which define the mathematical relationships are used to identify blood specimens with normal coagulation dynamics as distinguished from specimens with abnormal dynamics.

The digital filter and curve-fitting routine …

A Direct Method For Surface Structure Recovering Based On Uoff, Ping Lin

Theses

The unified optical flow field (UOFF) theory which can be used for estimating motion and recovering surface structure was recently established in [9, 10]. The direct method developed in [2, 3, 4, 6, 7] does not need to explicitly solve the optical flow field and to find feature correspondence. Based on the UOFF, a direct method in space domain is developed to reconstruct the curved surface structure characterized by an Nth degree polynomial equation from a pair of stereo images. The initial work on this new method was reported in [8, 11].

In this study, I basically work on simulation …