Engineering Commons^™

On The Mechanical Response In Boundary Resisted Motion, Maliha Maisha Rahman

Theses and Dissertations

In engineering and science literature, there seems to be a lack of consensus on a modeling framework clarifying how resistance to boundary motion affects mechanical performance. By mechanical performance, is implied the action of a force moving an object from one point to another that generates changes in position, velocity, acceleration and jerk. Apart from affecting a whole vehicle, critical power transmission components and subcomponents all rely on the mechanical responses that change due to an applied force. For example, the power needed to move an aircraft, an automobile, a ship, a submarine etc. will be reduced if resistance to …

Seismic Analysis Of Geosynthetic-Reinforced Soil (Grs) Bridge Abutments With Modular Block Facing, Roonak Ghaderi

Theses and Dissertations

The response of Geosynthetic Reinforced Soil (GRS) bridge abutments to earthquake loading remains a concern despite their great success under static loads. In order to advance and implement this new technology, especially in seismically active regions, this study was undertaken to examine the performance of GRS bridge abutments under seismic loads in a rational and critical manner.

This research is focused on single span, simply supported bridges. The current seismic design methods, including pseudo-static and displacement methods, are not specifically developed for GRS bridge abutments where the foundation of the bridge superstructure is placed on the top surface of the …

Synthesis And Characterization Of Microporous And Mesoporous Zeolites From Flyash For Heavy Metal Removal From Wastewater, Saeed Golbad

Theses and Dissertations

Class F fly ash was hydrothermally modified in one- and two-step processes to prepare zeolites with enhanced adsorption characteristics. Highly crystalline X type zeolite and hydroxy sodalite were targeted as microporous and mesoporous zeolite and were successfully synthesized using fly ash precursor by adjusting Si/Al molar ratio in reaction mixture. The heavy metal removal performance of the obtained fly ash-based zeolites was investigated in batch Pb2+ adsorption experiments.

Lead (Pb2+) is a positively charged toxic pollutant that can be present in surface water and industrial wastewater and may cause harmful physiological effects to human. As a result, standards for water …

Study Of Computational Image Matching Techniques: Improving Our View Of Biomedical Image Data, Ahmadreza Baghaie

Theses and Dissertations

Image matching techniques are proven to be necessary in various fields of science and engineering, with many new methods and applications introduced over the years. In this PhD thesis, several computational image matching methods are introduced and investigated for improving the analysis of various biomedical image data. These improvements include the use of matching techniques for enhancing visualization of cross-sectional imaging modalities such as Computed Tomography (CT) and Magnetic Resonance Imaging (MRI), denoising of retinal Optical Coherence Tomography (OCT), and high quality 3D reconstruction of surfaces from Scanning Electron Microscope (SEM) images. This work greatly improves the process of data …

Experimental Investigation Of Chicken Manure Pyrolysis And Gasification, Mohamed Hussein Hussein

Theses and Dissertations

The dependency on renewable resources of energy in power production is a necessary step that mankind has to take if we want our advances in life and technology to resume. In a century or two, fossil fuels will be depleted, and if we do not start to take action, Energy will be the most expensive and rare item on our planet. Biomass is one of the sources of renewable energy with an advantage of being the closest in characteristics to fossil fuels. The evolved gases are similar to fossil fuel gases which makes itthe easiest source to switch to, with …

Corrosion Of Aluminum Current Collector In Cost Effective Rechargeable Lithium-Ion Batteries, Shengyi Li

Theses and Dissertations

Rechargeable lithium ion batteries (LIB) have been widely used as commercial energy storage systems for portable equipment, electronic devices and high power applications (e.g. electronic vehicles). One issue with the commercialized LIB is that expensive, highly toxic and flammable organic solvents are used in the electrolyte and the fabrication process of electrodes. The toxic organic based solvents increase the production cost and lead to significant safety concerns in the event of a battery overcharge or short circuit. The recent development of “green manufacturing” technology allows manufacturers to replace the organic solvents used in the cathode coating process by aqueous based …

Durability Of Mechanically Loaded, Freeze Thawed Concrete Determined By Water Absorption, Brian Daniel Mitchell

Theses and Dissertations

The design of concrete bridges is primarily focused on strength characteristics. However, it is often the case that durability characteristics, specifically early deterioration of the bridge deck, requires expensive repairs before the designed service life of the bridge can come to term. Lin et al. (2012) identified the development of microcracks as a possible source of this early deterioration. He proposed that these microcracks propagated due to high local compressive stress induced by overweight trucks. The resulting permeability increase caused by the propagation of these microcracks is not significant enough to cause the kind of early deterioration of bridge deck …

Analyzing Transportation Services For Older Adults In Southeastern Wisconsin, Elizabeth Jean Saunderson

Theses and Dissertations

Older adults are important users to consider in the evaluation of transportation services. Many older non-drivers take fewer trips than their driving peers. It is important that transportation services meet the needs of older adults to provide greater access to this subset of the population. This thesis applies the Analytical Hierarchy Process (AHP) to evaluate the thirty-one non-private transportation services that exist in southeastern Wisconsin. The AHP structure uses multiple criteria to evaluate and rank several alternatives based on a stated goal. An optimization model using the LINGO solver introduces a fuzzy scale level to the AHP and assigns weights …

Travel Time Estimation On Urban Arterials - A Real Time Aspect, Jingcheng Wu

Theses and Dissertations

This dissertation attempts to develop simple and direct approaches to estimate the vehicle queue length and travel time along signalized arterial links for real-time traffic operations. This dissertation is the first to demonstrate a process using vehicle trajectory data to generate detector volume, speed and time occupancy data, along with the generalized flow rate, density and space mean speed data. This approach minimizes detector over-counting and miss-counting issues. The detection zone can be of any shape or size and at any location along the trajectory. The relationships among detector volume, speed and time occupancy along signalized arterials are analyzed theoretically …

Sensitivity Analysis Of Geometry Changes In The Simulation Of Basilar Aneurysms, Paul Eserkaln

Theses and Dissertations

Computer simulation is a useful tool in the research and treatment of basilar aneurysms. Current technology allows researchers to create 3D models from cerebral vasculature in-vivo, allowing for the investigation of surgical options with minimal risk to the patient. The method used to construct these models overlooks smaller lateral arterial branches which are difficult to discern due to resolution limits of the imaging process. These lateral branches have minimal impact on the overall blood flow through the basilar artery, but they play a significant role in the health of the patient, so it is important to ensure sufficient blood will …

Experimental Methods In Cryogenic Spectroscopy: Stark Effect Measurements In Substituted Myoglobin, Bradley Michael Moran

Theses and Dissertations

Dawning from well-defined tertiary structure, the active regions of enzymatic proteins exist as specifically tailored electrostatic microenvironments capable of facilitating chemical interaction. The specific influence these charge distributions have on ligand binding dynamics, and their impact on specificity, reactivity, and biological functionality, have yet to be fully understood. A quantitative determination of these intrinsic fields would offer insight towards the mechanistic aspects of protein functionality. This work seeks to investigate the internal molecular electric fields that are present at the oxygen binding site of myoglobin.

Experiments are performed at 1 K on samples located within a glassy matrix, using the …

High Temperature Oxidation Of Alumina Forming Cast Austenitic Stainless Steels Within An Environment Of Pure Steam, Elmer A. Prenzlow

Theses and Dissertations

Steam cracking of hydrocarbons in the petrochemical industry is a multibillion dollar industry. The processes performed in these plants create byproducts that negatively affect the integrity of stainless steel piping through high temperature corrosion. Alloys used presently in industry rely on the formation of chromium oxide (chromia) as a protective layer between the bulk metal pipe and chemical byproducts. However, chromia can become susceptible to attack from aggressive species such as carbon, water vapor, and sulfur compounds, thus creating a need for a better protection method.

A new series of austenitic stainless steels have been developed in recent years that, …

A Fuzzy Inference System Approach For Evaluating The Feasibility Of Product Remanufacture, Thomas Aming'a. Omwando

Theses and Dissertations

In the recent past, efforts have been made in enhancing sustainable manufacturing aimed at protecting the environment and saving natural resources. Among the efforts that have been explored include strategies to ensure responsible end-of-life product management so as reduce the impact on the environment and achieve effective use of resources. Towards this end, reduce, reuse and recycle product disposal strategies have found a lot of consideration in manufacturing. Of the product reuse strategies, remanufacturing has been widely applied owing to its unique feature of rendering the remanufactured product as good as new. For remanufacturers, this strategy leads to provision of …

Design And Basic Verification Of A Discrete Event Simulator For Glucose Metabolism In Human Beings, Elizabeth Andrews

Theses and Dissertations

This thesis describes the design and basic verification of a discrete event simulator for glucose metabolism in human beings. The simulator implements the glucose metabolism related behavior of various organs in the human body and tracks the blood plasma glucose level as the human body goes through a sequence of diet and exercise events. The simulator can mimic insulin resistance in various organs as well as the loss of insulin production in the pancreas and the adverse impact of these changes on the metabolic behavior of various organs. Thus, the simulator can serve as a model for people with diabetes. …

An Investigation Of The Effect Of Different Additives On The Compressive And Flexural Strength Of Rammed Earth, Aiham Alskif

Theses and Dissertations

The main objective of this research is to study the effect of using different additives on the compressive and flexural strength of rammed earth structures. Different ratios of fly ash, and/or cement were added to the soil to identify their influence on the compressive strength. Recycled fiber materials were used to wrap and reinforce the cement-soil specimens in order to enhance the flexural strength of beams and control the cracks and the mode of failure. The study finds that adding cement to soil has significant effect on the soil strength, and it causes a remarkable increase in the strength while …

Improving The Speech Intelligibility By Cochlear Implant Users, Behnam Azimi

Theses and Dissertations

In this thesis, we focus on improving the intelligibility of speech for cochlear implants (CI) users. As an auditory prosthetic device, CI can restore hearing sensations for most patients with profound hearing loss in both ears in a quiet background. However, CI users still have serious problems in understanding speech in noisy and reverberant environments. Also, bandwidth limitation, missing temporal fine structures, and reduced spectral resolution due to a limited number of electrodes are other factors that raise the difficulty of hearing in noisy conditions for CI users, regardless of the type of noise. To mitigate these difficulties for CI …

Investigation Of Sparsifying Transforms In Compressed Sensing For Magnetic Resonance Imaging With Fasttestcs, Christopher Adams Baker

Theses and Dissertations

The goal of this contribution is to achieve higher reduction factors for faster Magnetic Resonance Imaging (MRI) scans with better Image Quality (IQ) by using Compressed Sensing (CS). This can be accomplished by adopting and understanding better sparsifying transforms for CS in MRI. There is a tremendous number of transforms and optional settings potentially available. Additionally, the amount of research in CS is growing, with possible duplication and difficult practical evaluation and comparison. However, no in-depth analysis of the effectiveness of different redundant sparsifying transforms on MRI images with CS has been undertaken until this work. New theoretical sparsity bounds …

In-Situ Optical Microscopic Investigation Of The Dendrite Formation On Lithium Anode Under Different Electrolyte Conditions In Li-S Battery, Tianyao Ding

Theses and Dissertations

By utilizing a high-resolution optical microscope, the dendrite formation on a lithium electrode with different electrolytes suitable for Li-S battery was investigated. It is found that the anions of lithium, the solvents, and the deposition current density have significant effects on the dendrite formation and surface morphology of lithium electrodes in electrolytes without polysulfides. On the contrary, in electrolytes with 25 mM concentration of polysulfides, the dendrite formation and surface morphology tend to be similar regardless of the other conditions. The dendrite-suppression effect of polysulfides, inorganic additive (CsNO3), and electrode modifier (TEOS) are not significant in the electrolytes with polysulfides …

Quantitative Optical Studies Of Oxidative Stress In Rodent Models Of Eye And Lung Injuries, Zahra Ghanian

Theses and Dissertations

Optical imaging techniques have emerged as essential tools for reliable assessment of organ structure, biochemistry, and metabolic function. The recognition of metabolic markers for disease diagnosis has rekindled significant interest in the development of optical methods to measure the metabolism of the organ.

The objective of my research was to employ optical imaging tools and to implement signal and image processing techniques capable of quantifying cellular metabolism for the diagnosis of diseases in human organs such as eyes and lungs. To accomplish this goal, three different tools, cryoimager, fluorescent microscope, and optical coherence tomography system were utilized to study the …

Aesthetic Coatings For Concrete Bridge Components, Brent Kriha

Theses and Dissertations

This thesis evaluated the durability and aesthetic performance of coating systems for utilization in concrete bridge applications. The principle objectives of this thesis were: 1) Identify aesthetic coating systems appropriate for concrete bridge applications; 2) Evaluate the performance of the selected systems through a laboratory testing regimen; 3) Develop guidelines for coating selection, surface preparation, and application.

A series of site visits to various bridges throughout the State of Wisconsin provided insight into the performance of common coating systems and allowed problematic structural details to be identified. To aid in the selection of appropriate coating systems, questionnaires were distributed to …

Developing Sampling Strategies And Predicting Freeway Travel Time Using Bluetooth Data, Hasan Md Moonam

Theses and Dissertations

Accurate, reliable, and timely travel time is critical to monitor transportation system performance and assist motorists with trip-making decisions. Travel time is estimated using the data from various sources like cellular technology, automatic vehicle identification (AVI) systems. Irrespective of sources, data have characteristics in terms of accuracy and reliability shaped by the sampling rate along with other factors. As a probe based AVI technology, Bluetooth data is not immune to the sampling issue that directly affects the accuracy and reliability of the information it provides. The sampling rate can be affected by the stochastic nature of traffic state varying by …

Computational Modeling Of Transient Processes During Run-In For Tribological Systems, Rob Morien

Theses and Dissertations

Understanding the frictional behavior of machine elements in mutual rolling or sliding contact is important for many engineering applications. When frictional sliding is initiated, the tribological system passes through several stages with each stage possessing its own unique frictional property. The initial transition process preceding stationary sliding is usually called “run-in”. During the run-in time interval, surface topographies of frictional contacts as well as lubricant distribution and surface tribofilms reorganize and adjust through asperity deformation and wear processes before reaching the steady state. This surface stability formed during run-in leads to an improvement in frictional performance during steady state operation, …

Solid State Protective Device Topological Trade-Offs For Mvdc Systems, Vikas Singh

Theses and Dissertations

Presently accepted approaches to protection are “Unit-Based” which means the power converter(s) feeding the bus coordinate with no-load electromechanical switches to isolate faulted portions of the bus. However, “Breaker-Based” approaches, which rely upon solid state circuit breakers for fault mitigation can result in higher reliability of power and potentially higher survivability. The inherent speed of operation of solid state protective devices will also play a role in fault isolation, hence reducing stress level on all system components. A comparison study is performed of protective device topologies that are suitable for shipboard distribution systems rated between 4kVdc and 20kVdc from the …

Microstructure, Wetting Angle And Corrosion Of Aluminum-Silicon Alloys, Shvetashva Suri

Theses and Dissertations

In this study the effect of composition, surface roughness and water droplet size on contact angle and corrosion properties of cast Aluminum-Silicon alloys containing Si from 5% to 50% have been examined. The water contact angle was measured on a given sample using a goniometer. In addition, the effect of surface roughness and droplet size on contact angle has been measured for alloys at a fixed composition. The microstructures can be found in this report with sizes of primary and eutectic Silicon as well as inter-particle spacing between Silicon. Contact angle measurements are accompanied with a photographic validation of the …

Representative Volume Element (Rve) Finite-Element Analysis (Fea) Of Al Metal-Matrix Composites, Yuzhe Cao

Theses and Dissertations

ABSTRACT

REPRESENTATIVE VOLUME ELEMENT (RVE) FINITE-ELEMENT ANALYSIS

(FEA) OF AL METAL-MATRIX COMPOSITES

by

Yuzhe Cao

The University of Wisconsin-Milwaukee, 2016

Under the Supervision of Professor Chang-Soo Kim

Metal matrix composites reinforced by particles (a.k.a particle reinforced metal matrix composites, PRMMCs) could be suitable for a large number of applications with their enhanced mechanical properties. These composites generally consist of a base metal filled with hard/strong particles of which physical and mechanical properties very different from those of the matrix. These particles are intended to improve the properties of the base material including wear resistance, damping properties, and mechanical strength. Aluminum …

Experimental, Analytical And Numerical Characterization Of Effects Of Fiber Waviness Defects In Laminated Composites, Seyedmohammadsadegh Shams

Theses and Dissertations

Fiber waviness is one of the most common defects observed in reinforced laminated composites which can occur during manufacturing. The effects of waviness on the mechanical responses of laminated composites under the standard mechanical testing are investigated with proposed experiments, analytical and numerical approaches. The damage consequences including kink band formation, crack onset, delamination and fiber fractures are characterized by means of full field digital imaging and acoustic emission techniques. The notch and waviness size effects on the notched composite compressive and tensile strength are studied using a progressive damage approach using the finite element method. A numerical approach based …

Probabilistic Reliability Analysis Of Electric Power Systems With Smart Grid Technologies And Water Distribution Networks: Modeling, Assessment, And Comparison, Ruosong Xiao

Theses and Dissertations

With the rapid growth of population, the modern human society is becoming more and more dependent on the proper operation of critical infrastructures - the interconnected electrical power system, the drinking water distribution and supply system, the natural gas transmission and distribution system, and so forth. It has become an important issue to maintain reliable functions of these critical systems. As a result, comprehensive reliability evaluation is highly needed to quantify their reliability in an objective manner. Conventionally, deterministic criteria were used in reliability evaluations. However, it lacked the ability to model and quantify the stochastic nature of system behaviors …

Mhealth Technology: Towards A New Persuasive Mobile Application For Caregivers That Addresses Motivation And Usability, Suboh M. Alkhushayni

Theses and Dissertations

With the increasing use of mobile technologies and smartphones, new methods of promoting personal health have been developed. For example, there is now software for recording and tracking one's exercise activity or blood pressure. Even though there are already many of these services, the mobile health field still presents many opportunities for new research.

One apparent area of need would be software to support the efforts of caregivers for the elderly, especially those who suffer from multiple chronic conditions, such as cognitive impairment, chronic heart failure or diabetes. Very few mobile applications (apps) have been created that target caregivers of …

Rational Design Of Cathode Materials For High Performance Lithium-Sulfur Batteries, Xi Chen

Theses and Dissertations

Sulfur, one of most promising cathode candidates for next-generation lithium ion batteries, shows a limited cycling performance due to its shuttling effect, low conductivity, self-discharge and volume expansion during lithiation and delithiation process. According to the operation principles, failure mechanism, and recent progress on lithium-sulfur batteries, here we developed several scalable and rational synthesis methods for high performance cathode materials. We dissolved commercial sulfur to anhydrous ethylenediamine (EDA) to form an EDA-S precursor, and then we reduced the sulfur particles size at conductive carbon black substrate. The 70% theoretical capacity of sulfur cathode battery was obtained. We also melted commercial …

Dynamic Mechanical Analysis Of Kissing Bonds In Bonded Joints, Tasha Graciano Graciano

Theses and Dissertations

Inspection of kissing bond defects in composite structures is a challenge for traditional nondestructive testing (NDT) methods. A kissing bond (KB) is a bondline defect where two surfaces are in intimate contact with each other but with little to no bond strength. New nondestructive testing methods need to be developed that can detect adhesive kissing bonds, and areas within a composite joint where the bondline is compromised. The primary goal of this thesis is to explore if a NDT technique based on Dynamic Mechanical Analysis (DMA) can be established which is capable of detecting kissing bonds within bondlines in composite …