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Characterization Of New Particulate Mmc Materials And Bolted Joints Through Applicable Astm Standards, Vinu Zacharia Mathew

Graduate Theses, Dissertations, and Problem Reports

Particulate reinforced metal matrix composites (PRMMC) comprise a new class of materials whose properties can be adjusted to suit a particular application. The main purpose of producing PRMMC is to achieve lightweight materials with added properties like high stiffness, high ultimate strength and hardness.;In this study we deal with PRMMC manufactured by a novel technology involving the pressure less infiltration of aluminum into a mass of ceramic reinforcement particles. Basic tests like tension test, three point bending test, hardness tests and coefficient of thermal expansion are conducted according to the ASTM standards in order to characterize the material. All these …

Permeability And Strength Of Artificially Controlled Porous Media, Suresh Pasumarty

Graduate Theses, Dissertations, and Problem Reports

Oil well industry has been using hydraulic fracturing to open new channels and thus increase well productivity. Materials known as Proppants are injected into the fracture to keep the channels conductive after the applied hydraulic pressure is removed. But the proppants used to date are often crushed under the influence of rock closures, which leads to clogging of the channel.;The main objective of this study was to model a material that would be able to withstand the rock closure stresses and also remain conductive. A three-dimensional finite element model was developed to study the effects of the shape and the …

Modeling Of An Aluminum Reduction Cell For The Development Of A State Estimator, Philip Biedler

Graduate Theses, Dissertations, and Problem Reports

Electrolytic cells are used to produce aluminum from alumina ore. These cells use a carbon anode, a cryolitic bath, and a carbon containment vessel, which also serves as the cathode. The process is not completely understood because of the limited number of measurements and its complexity.;A finite element model was developed that simulates the electrical, thermal, and chemical phenomena occurring within the cell. The model was verified by comparing its output to data presented in the literature, and by comparing its output to data gathered from operating reduction cells at Century Aluminum in Ravenswood, WV. The model was used to …

Spatial And Temporal Considerations In Vehicle Path Tracking With An Emphasis On Spatial Robustness, Donald L. Cripps

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This dissertation researches the task and path management of an autonomous vehicle with Ackerman-type steering.

The task management problem was approached as a path training operation in which a human operator drives the desired path through an environment. A training trajectory is converted into a series of path segments that are driveable by the autonomous vehicle by first fitting a general path to the dataset. Next, transition segments are added to the general path to match the vehicle velocity and steering angle rate limit.

The path management problem has been approached by first deriving a kine- matic model of the …

Design And In Situ Testing Of A Piezometer System To Measure Earthquake -Induced Pore -Pressure Changes, Robert Farrell

Doctoral Dissertations

Pore pressure changes have been measured in fine sand deposits that are known to have liquefied during earthquakes. Some of the measured signals have not been similar to what was expected during earthquake-induced liquefaction. Using artificially generated signals, several investigators have attempted to determine if existing piezometer fields designed to measure earthquake induced pore pressure changes are operating correctly. The signals generated during one investigation were not similar to those expected from an earthquake. In another investigation, while the generated signals were similar to ones expected from an earthquake, the results were not reproducible; the generated signals damaged the aquifer …

Assessment Of The Fate Of Cryptosporidium Parvum, Giardia Lamblia And Ascaris Lumbricoides In Class A Composting And Class B Lime Stabilization Biosolids Treatment Processes, Christine L. Bean

Doctoral Dissertations

The management of biosolids in the United States has become an issue of public health concern in regard to disposal. Congress created the Clean Water Act in 1972 to protect waters in the United States and as a result, no longer can human waste be dumped into oceans or rivers. Means of disposal of biosolids are focused on land application today. The practice of land application takes into consideration the classification of the biosolids material and management practices to control access to and growth of crops on the land. Biosolids are classified as either Class A or Class B depending …

The Impact Of Coating Architecture On The Hardness, Friction And Wear Resistance Of Hard And Tribological Nanocomposite Coatings, Jose Luis Endrino

Doctoral Dissertations

Future generations of mechanical systems will place new demands on the tribological performance of interacting surfaces. Vapor-deposited surface coatings can provide extended lifetimes, increased efficiencies and energy savings for mechanical components and tools. These benefits can also be extended to space mechanisms and satellites with the use of vacuum solid lubricants. The material properties of surface coatings such as hardness, friction, and wear resistance in a particular environment are influenced by the characteristics of the coating microstructure which include density, grain size, grain boundary chemistry, porosity, and grain orientation.

In this research effort bias sputter deposition, co-sputtering, and magnetron sputtering-pulsed …

Active Disturbance Cancellation In Nonlinear Dynamical Systems Using Neural Networks, John C. Canfield

Doctoral Dissertations

A proposal for the use of a time delay CMAC neural network for disturbance cancellation in nonlinear dynamical systems is presented. Appropriate modifications to the CMAC training algorithm are derived which allow convergent adaptation for a variety of secondary signal paths. Analytical bounds on the maximum learning gain are presented which guarantee convergence of the algorithm and provide insight into the necessary reduction in learning gain as a function of the system parameters. Effectiveness of the algorithm is evaluated through mathematical analysis, simulation studies, and experimental application of the technique on an acoustic duct laboratory model.

A Wavelet-Based Cmac For Enhanced Multidimensional Learning, Brian P. Kirk

Doctoral Dissertations

The CMAC (Cerebellar Model Articulation Controller) neural network has been successfully used in control systems and other applications for many years. The network structure is modular and associative, allowing for rapid learning convergence with an ease of implementation in either hardware or software. The rate of convergence of the network is determined largely by the choice of the receptive field shape and the generalization parameter. This research contains a rigorous analysis of the rate of convergence with the standard CMAC, as well as the rate of convergence of networks using other receptive field shape. The effects of decimation from state-space …

In-Situ Study Of The Influence Of Additives On The Growth Behavior Of Copper Electrodeposits On Copper Single Crystal, Aiwen Wu

Doctoral Dissertations

Trace organic additives are known to be essential in obtaining desired metal electrodeposits in the microelectronic industry, however, fundamental design principles for their use and a scientific understanding of their interaction during electrodeposition is lacking. In the present study we investigated electrodeposition of copper on the Cu(100) surface in air-saturated or dearated acid-sulfate plating solutions containing several combinations of chloride and additives benzotriazole (BTA) and 3-mercapto propane sulfonic acid (MPSA) under galvanostatic pulse-current conditions. The electrodeposition process was followed using in-situ atomic force microscopy (AFM). AFM images were quantitatively analyzed by pattern-recognition and scaling procedures.

In the absence of additives, …

Some Contributions To The Hydraulic Characterization Of Fractured Bedrock Formations, Gonzalo Pulido

Doctoral Dissertations

During 3 years of investigation at the BBC field site, research has led to developments in bedrock monitoring, groundwater sampling, formation hydraulic testing, and the conceptual model of formation hydraulics. This dissertation presents a field device, two hydraulic test methods, and one method of hydraulic test analysis developed to assist in the hydraulic characterization of fractured bedrock formations. It also presents the use of these tools in the development of the Conceptual Hydrogeologic Model for a fractured bedrock formation contaminated with chlorinated solvents. The field device was named the Multipurpose Packer System (MPS), a discrete-interval isolation system for the sampling …

A Mems Acoustical Sensor Array And Associated Micropackage., Sazzadur Chowdhury

Electronic Theses and Dissertations

This thesis develops the design methodology and fabrication procedures for a MEMS-based square planar acoustical sensor microarray for use in a hearing instrument to improve speech intelligibility in noisy and reverberant environments. The proposed microarray offers the potential of controlled directional sensitivity with a reasonably constant beamwidth over the audio frequency range when used in conjunction with an appropriate digital signal processor. The microarray consists of nine identical square-shaped capacitive-type acoustical sensors in a 3 x 3 planar layout and has a footprint area of 4.6 x 4.6 mm2 . Each sensor has a sensitivity of 10.3 mV/Pa when biased …

Submergence Effects On Local Scour., Md Rajib. Ahsan

Electronic Theses and Dissertations

The study discussed herein focuses on the local scour created in a cohesionless sand bed by a plane turbulent wall jet with varying levels of submergence from 1 to 20. From the observations of 40 experiments the study reveals that the formation of unstable scour processes, which can be short and long-term in nature, depends on the water depth available above the mound apex for a given initial jet velocity. In case of stable scour process, the growth of the scour hole dimensions follows a linear relation with the logarithm of time beyond which the rate of change in the …

Fundamentals And Process Modeling Of Supersonically Induced Mechanical Alloy Technology (Simat(Tm)) For Engine Production., Evgeny. Leshchinsky

Electronic Theses and Dissertations

Conventional Metal Powder Coatings, designed to obtain anti-corrosive, wear and thermal resistant properties, are studied and their properties are analyzed. The capabilities of the Supersonically Induced Mechanical Alloy Technology are investigated with the purpose to enhance the surface strength and durability, simplify the deposition procedure and increase service time. A new spray deposition process is shown and compared with other different methods of Metal Powder Coating deposition. A new method is developed that is less expensive and operates with similar load mechanisms on powder particles. High strain rate deformation can be easily studied by special powder compaction. In this method, …

High-Performance Mortar Reinforced With Short Carbon Fibers., Md. Safiuddin

Electronic Theses and Dissertations

The aim of the work reported in this thesis was to evaluate the performance of carbon fiber reinforced mortar in respect of workability, strength, impact resistance, toughness, durability, and cost-effectiveness. Laboratory experiments were carried out to investigate the properties of both fresh and hardened mortars reinforced with short carbon fibers and to optimize the mix with sufficient workability, good strength, superior impact resistance, enhanced toughness, and excellent durability at reasonable cost. Experimental investigation was carried out at the Concrete Laboratory of the University of Windsor. Five different types of mortar were taken under study including the control mortar based on …

Phoneme-Based Speech Recognition Using Self-Organizing Map., Xiaofeng. Dong

Electronic Theses and Dissertations

Automatic speech recognition by machine is a challenging task for man-machine communications. Because speech waveform is nonlinear and variant, a speech recognition algorithm requires much intelligence and an ability to accommodate variations. In this thesis, a hybrid speech recognizer based on self-organizing map (SOM) and fuzzy neural network (FNN) is proposed. The SOM is used to obtain the optimal phoneme response patterns of speech signal by Viterbi search algorithm and the FNN is applied for the recognition matching of these 2D speech response patterns on the SOM to fulfill the speech recognition tasks. Experiment results show that this hybrid speech …

Mems Microphone Design., James Sliepenbeek

Electronic Theses and Dissertations

This thesis presents an overview of microelectromechanical (MEMS) capacitive type microphone design for use in hearing instruments. A cohesive methodology is achieved via a mechanical equation of motion. Resulting in displacement, change in capacitance, sensitivity and pull-in voltage. All derived from one equation. From this investigation it is apparent that sensitivity is the most important factor in MEMS microphone design. The topics covered in the overview are: MEMS microphone design considerations, comparison of microphone types, signal detection methods, sources of dampening, modeling methods, sensitivity estimation, pull-in voltage estimation, bias voltage, ultimate tensile strength, design space optimization and MEMS microphone design …

A 2-Digit Multidimensional Logarithmic Number System Filterbank Processor For A Digital Hearing Aid., Hongbo (Jennifer). Li

Electronic Theses and Dissertations

This thesis addresses the design, implementation, and evaluation of a filterbank for digital hearing aids using a Multidimensional Logarithmic Number System (MDLNS). Hearing loss is a function of both frequency and input level. In a typical digital hearing instrument, the hearing loss compensation is performed by separating the incoming sound into several frequency bands which are then compressed to allow the amplification of low level signals while maintaining the amplitude of high level signals. The demands of low power consumption and small size have led to a number of advances in algorithms, semiconductor technologies and system architectures for completely-in-canal (CIC) …

The Addition Of Hydrogen And Oxygen To A Gasoline-Fuelled Si Engine To Enhance Combustion And Reduce Emissions., Tina. D'Andrea

Electronic Theses and Dissertations

Automobiles have become an essential part of our economy and provide a convenience that most have become dependent on, however they have also had a dramatic impact on our health and environment. As a result there is an incentive to find ways to more efficiently use conventional fuels and decrease emissions while alternative fuels and vehicles are being developed. This research involved studying the effects of adding small amounts of hydrogen and hydrogen and oxygen to a gasoline fuelled spark ignition (SI) engine. The hydrogen and oxygen were added in a ratio of 2:1, mimicking water electrolysis products. It was …

The Effect Of Localized Muscle Fatigue On Tibial Impact Acceleration., Janice Marie. Flynn

Electronic Theses and Dissertations

Tibial impact acceleration measured during running is known to increase with general body fatigue. The purpose of this study was to determine if localized muscle fatigue of the shank muscles would also cause an increase in peak tibial acceleration. The human pendulum system was used to control impact velocity and joint angle. There were 24 women participating in the study: 12 between the ages of 20--25, and 12 between 50--60 years. Each lay supine on the pendulum, and their unshod dominant heel was impacted into a vertical force plate with a velocity between 1--1.15 m/s, and a force approximating 1.8--2.8 …

The Effect Of Novel Solution Treatment During The Solidification Process On The Structure And Mechanical Properties Of The W319 Alloy., Xin Chen

Electronic Theses and Dissertations

A Novel Accelerated and Continuous solution treatment (ST), which is known as the Novel Solution Treatment during the Solidification Process (NSTS), was performed on the W319 Al alloy. The metallographic analyses of the test samples showed that the NSTS process allows for the dissolution of the Cu enriched phases as well as Mg and Si based phases during a shorter period of time (between 30 and 60 minutes at a temperature between 510°C and 530°C) in comparison with the solution treatment (ST) process (over 5 hours at a temperature of 495°C) used by Nemak Windsor Aluminum Plant (WAP). The metal …

Piles Embedded In Soft Clay Located Below The Water Table Subjected To Lateral Cyclic Loadings: Sensitivity Analysis., Deni Gunawan. Priyanto Putro

Electronic Theses and Dissertations

This study presents the theoretical formulation and numerical investigations of sensitivity analysis of laterally loaded piles embedded in soft clay located below the water table. Single piles with various lengths and boundaries subjected to cyclic lateral forces and bending moments are analyzed. The groups of 3 x 3 piles with various spacing (2D, 3D, 4D, and 5D) are also analyzed in this study. For single piles, the pile structure is considered as one-dimensional beam and the supporting soft clay is defined by means of p-y model. For groups of piles, the pile members are considered as one-dimensional beams and the …

Plastic Liberation Through The Comminution Of Composite Manufactured Product Wastes, Lawrence Jekel

Electronic Theses and Dissertations

The automotive industry is examining alternative designs of systems and components that facilitate material recovery during the processing of end-of-life vehicles. Specifically, if materials or components can be designed to separate preferentially, then material recovery from product waste will be enhanced. Two waste concepts were examined for their practical value: (1) size distribution and the related Pi Breakage theory; and (2) the liberation of materials. Samples consisting of ABS and PVC were assembled with a variety of geometries, characteristic lengths, subcomponent configurations and fastening methods. A detailed evaluation of thermoplastic comminution found that particle size distributions fit the Gaudin size …

Speech Analysis And Synthesis Based On Arma Lattice Model., Min. Wang

Electronic Theses and Dissertations

The research documented in this thesis presents a pitch synchronous speech analysis and synthesis system using an ARMA (auto regressive moving average) lattice filter. The LP (linear predictive) model is, by far, the most widely used speech production model in speech processing. A well-known drawback with the LP model is that it ignores the effect of the nasal cavity. The mismatch between the model and the vocal tract becomes severe for nasal sound production and leads to poor synthesized speech. The nasal tract effect can be included in the speech production model by representing the vocal tract with an ARMA …

Flexural Strength Of Circular Monopole Flange Connections., Venisri. Nagulapati

Electronic Theses and Dissertations

This investigation focuses on the flexural strength of circular flange connections in monopoles with particular attention to the role of stiffeners. Four finite element models---(a) 25.4 mm thick flange unstiffened connection, (b) 25.4 mm thick flange stiffened connection, (c) 19.1 mm thick flange unstiffened connection and (d) 19.1 mm thick flange stiffened connection, with eight 25.4 mm diameter bolts for each connection, were developed. The finite element models were validated by comparing the finite element failure loads, deflections and strains with experimental values. Five test specimens were 25.4 mm thick stiffened flange connections (with different orientations of stiffeners), three test …

Identification Of Dynamic Characteristics Of Linear Systems., Md. Mizanur Rahman

Electronic Theses and Dissertations

Structures, built in active earthquake zones, can be subjected to damaging dynamic loading. The health monitoring process for these structures is essential. When a structure is submitted to repetitive moderate earthquake events, it is expected to accumulate certain damage. The variation of the dynamic characteristics can be an indicator of the damage extension in a structure. The procedure of evaluating the dynamic characteristics of a structure is referred to as system identification. This investigation focuses on the analysis of different techniques for identifying linear structures with available recorded responses during earthquake events. These approaches are: (i) Fourier transform approach; (ii) …

Implementation Of The Maturity Method Into Precast Concrete Applications., Alvin. Olar

Electronic Theses and Dissertations

The personnel at Prestressed Systems Incorporated (PSI) suspected that use of the zero slump test cylinders to measure the compressive strength of hollowcore concrete was not reliable. If a test cylinder failed only by a chipped edge while being tested for compressive strength, it was not useful for determining the time at which the prestressing force in the tendons can be transferred into the bed of hollowcore. A more reliable method was sought to quantify the compressive strength of zero slump concrete at the time of tendon release. The method should also provide real-time information on the progress of concrete …

Integrated Durability Analysis Of A Vehicle Through Virtual Simulation., Craig Wood

Electronic Theses and Dissertations

The intent of this research is to create a high fidelity multibody dynamics model of a compact Sport Utility Vehicle (SUV) using CATIA, ADAMS and NASTRAN software suites. These software packages together are used to conduct virtual proving ground simulations. An MTS 329 series Road Test Simulator (RTS), which uses servo-hydraulic actuators to replicate vehicle proving ground is used to correlate results. The overall objective is to be able to predict component failure earlier in the design process, and to reduce the amount of time spent conducting physical durability tests. This thesis builds on research currently being conducted by many …

Design Of Iir Filters With Canonical Signed-Digit (Csd) Coefficients Using Genetic Algorithms., Li. Liang

Electronic Theses and Dissertations

In this thesis, an optimization method is used in the design of 1-D IIR digital filters, doubly complementary filter pairs and 2-D IIR digital filters. This method uses genetic algorithm (GA) to minimize the mean square error between the desired and the designed filter responses in order to calculate the coefficients of the filter's transfer function. The 1-D IIR filters are designed using cascade structure, and constraints are imposed on the coefficients of the denominator polynomials to ensure stability. In the one-dimensional case, the method is also used to design doubly complementary filter pairs, in which case two filters that …

Detection Of Cylinder Bore Non-Cleanup Using Modeling Of Piston Ring Dynamics., Matthew. Bitzer

Electronic Theses and Dissertations

A study was undertaken to develop a method of detecting an automotive engine manufacturing defect known as cylinder bore non-cleanup. This defect is best described as a rough surface finish inside any cylinder bore of an engine. This defect causes increased piston ring wear and engine noise and vibration. Recently published literature on engine vibration analysis and defect detection is presented. Special emphasis was placed on engine dynamic modeling. This study examines the effects of cylinder bore non-cleanup on the motion of the piston rings. This is accomplished by modeling the dynamics of the piston and piston rings using a …