Engineering Commons^™

Rheology Of Cross-Linked Polymers And Polymer Foams: Theory And Experimental Results, John Herman

Wayne State University Dissertations

Typical polymers have a time-dependent response to loading which results in stress relaxation or creep. Models using springs/dashpots or Volterra integrals are capable of predicting the material response, but place little or no emphasis on the reasoning behind the response. This research proposes a microscopic reasoning behind polymer chain movement, while developing a model to predict the creep and stress relaxation of a polymer foam. Based on the theorized slip/stick of polymer chains as they slide past each other, this model successfully predicts the behavior of a PMI polymer foam under tensile loads. This model lends insights into polymer microscopic …

A Framework To Improve A Nation's Competitiveness Through Quality Awards And Performance Improvement Tools, Amr Alamri

Wayne State University Dissertations

Each country, represented by its government, aims to serve its citizens better. This is achieved by better utilization of resources and higher productivity. The ability to do so will lead to a competitive nation. Recently, countries were able to compare themselves in terms of competitiveness using international indexes and references. These references gave countries a benchmark to know where they exist compared to other nations. They help governments to understand their strengths and weaknesses within the competitiveness components. However, nations differ in the actions which are to be taken in order to improve their competitiveness. Governments establish and regulate many …

Lean Thinking For Lead-Time Reduction And Efficient Knowledge Creation In Product Development, Satish Kumar Tyagi

Wayne State University Dissertations

There are many distinct differences between manufacturing process and Product Development (PD) process, so lean tools have to be customized to deliver results in the later domain. The main focus of this dissertation is to extend them to manage and improve the PD process in order to develop the product faster while improving or at least maintaining the level of performance and quality. For aforesaid purpose, value stream mapping (VSM) method is used to explore the wastes, inefficiencies, non-valued added steps in a single, definable process out of complete PD process. Besides numerous intangible benefits, VSM framework will help the …

Modeling And Optimization Of Non-Profit Hospital Call Centers With Service Blending, Yanli Zhao

Wayne State University Dissertations

This dissertation focuses on the operations problems in non-profit hospital call centers with inbound and outbound calls service blending.

First, the routing policy for inbound and outbound calls is considered. The objective is to improve the system utilization under constraints of service quality and operators' quantity. A collection of practical staffing assignment methods, separating and mixing staffing policy are evaluated. Erlang C queuing model is used to decide the minimum number of operators required by inbound calls. Theoretical analysis and numerical experiments illustrate that through dynamically assigning the inbound and outbound calls to operators under optimal threshold policy, mixing staffing …

Reliability Analysis And Optimal Maintenance Planning For Repairable Multi-Component Systems Subject To Dependent Competing Risks, Nailong Zhang

Wayne State University Dissertations

Modern engineering systems generally consist of multiple components that interact in a complex manner. Reliability analysis of multi-component repairable systems plays a critical role for system safety and cost reduction. Establishing reliability models and scheduling optimal maintenance plans for multi-component repairable systems, however, is still a big challenge when considering the dependency of component failures. Existing models commonly make prior assumptions, without statistical verification, as to whether different component failures are independent or not. In this dissertation, data-driven systematic methodologies to characterize component failure dependency of complex systems are proposed. In CHAPTER 2, a parametric reliability model is proposed to …

Development Of Scaffold Architectures And Heterotypic Cell Systems For Hepatocyte Transplantation, Dalia Alzebdeh

Wayne State University Dissertations

In vitro assembly of functional liver tissue is needed to enable the transplantation of tissue-engineered livers. In addition, there is an increasing demand for in vitro models that replicate complex events occurring in the liver. However, tissue engineering of sizable implantable liver systems is currently limited by the difficulty of assembling three dimensional hepatocyte cultures of a useful size, while maintaining full cell viability, an issue which is closely related to the high metabolic rate of hepatocytes. In this study, we first compared two designs of highly porous chitosan-heparin scaffolds seeded with hepatocytes in dynamic perfusion bioreactor systems. The aim …

A Prediction Modeling Framework For Noisy Welding Quality Data, Junheung Park

Wayne State University Dissertations

Numerous and various research projects have been conducted to utilize historical manufacturing process data in product design. These manufacturing process data often contain data inconsistencies, and it causes challenges in extracting useful information from the data. In resistance spot welding (RSW), data inconsistency is a well-known issue. In general, such inconsistent data are treated as noise data and removed from the original dataset before conducting analyses or constructing prediction models. This may not be desirable for every design and manufacturing applications since every data can contain important information to further explain the process. In this research, we propose a prediction …

A Biomechanical Assessment Of Canine Body Armor, Sarah Stojsih

Wayne State University Dissertations

The purpose of this research was to establish a biomechanical assessment of canine body armor with a primary focus on civilian law enforcement canines. The specific aims included: 1) the compilation of canine casualty data to determine commonly reported causes of death/euthanasia while in service for civilian law enforcement canines, 2) the evaluation of the biomechanical response of the canine related to a behind armor blunt impact, 3) the identification of an injury criterion that will best predict canine thoracic injury as a result of behind armor blunt trauma, 4) correlation of the behind armor blunt trauma response to the …

Development Of High Strength High Toughness Third Generation Advanced High Strength Steels., Codrick John Martis

Wayne State University Dissertations

Third generation advanced high strength steels (AHSS's) are emerging as very important engineering materials for structural applications. These steels have high specific strength and thus will contribute significantly to weight reduction in automotive and other structural component. In this investigation two such low carbon low alloy steels (LCLA) with high silicon content (1.6-2wt %) has been developed. These two steel alloys were subjected to single step and two step austempering in the temperature range of 260-399oC to obtain desired microstructures and mechanical properties. Austempering heat treatment was carried out for 2 hours in a molten salt bath. The microstructures were …

Benefit-Cost Analysis Of Using Class F Fly Ash-Based Green Cement In Masonry Units, Khaled Shwekat

Wayne State University Dissertations

ABSTRACT

BENEFIT-COST ANALYSIS OF USING CLASS F FLY ASH-BASED GREEN CEMENT IN MASONRY UNITS

by

KHALED SHWEKAT

August 2015

Advisor: Dr. Hwai-Chung Wu

Major: Civil engineering

Degree: Doctor of Philosophy

The Portland cement concrete is the most popularly used building material around the world. However, there are major drawbacks associated with Portland cement, such as the emission of greenhouse gasses and high-energy consumption from cement production. Therefore, Portland cement concrete has many disadvantages that can only be overcome by being replaced with new materials such as fly ash-based green cement. Recycling fly ash and using it to replace cement has …

Analysis Of Queue Characteristics At Signalized Intersections Near Highway-Railroad Grade Crossing, Amna Chaudhry

Wayne State University Dissertations

Analysis of traffic queues at signalized intersections which are in close proximity to highway- railroad grade crossings is of primary importance for determining if the normal signal operation needs to be preempted for railroad operations by providing a special signal mode for safe clearance of the queued vehicles from the tracks before the train arrival, and prohibiting any conflicting traffic movements towards the crossing. Such queuing analysis becomes even more critical where direct observations of traffic queues are not possible or where the assessment is needed for a future location. Inadequate estimation of queues from signalized intersections to the nearby …

Face Sheet/Core Debonding In Sandwich Composites Under Static And Fatigue Loading, Manjinder Singh Warriach

Wayne State University Dissertations

Delamination growth due to face sheet/core debonding is a major concern due to its inherent weakness in sandwich composites which can be exacerbated due to the presence of flaws. In this research work The primary objective of this research was to characterize the delamination crack growth behavior in E-glass face sheet/polyurethane foam core sandwich composite with pre-existing initial delamination crack at a face sheet/core interface under static and fatigue for mode I and mixed mode loading. For mode I static loading two types of delamination experiments, namely T-peel test and wedge test were implemented to evaluate fracture toughness in polyurethane …

Helmholtz Equation Least Squares Based Near-Field Acoustic Holography With Laser, Wu Zhu

Wayne State University Dissertations

This dissertation presents the HELS based NAH with laser and use normal surface velocity as input in near-field acoustic holography. The conventional HELS based NAH uses acoustic pressure as input to reconstruct sound field quantities, while this modified HELS based NAH with laser utilizes the normal surface velocities measured by LDV to reconstruct the acoustic quantities at interested positions. Theoretical principles of the HELS based NAH with laser have been fully developed and the method has been verified in theoretical perspective. Two theoretical examples verify that HELS based NAH with laser can obtain exactly the same results as analytic solution. …

Accurate And Efficient Reliability Analysis Of Complex Structural Engineering Problems, Kapil Dilip Patki

Wayne State University Dissertations

ABSTRACT

ACCURATE AND EFFIFICIENT RELIABILITY ANALYSIS OF COMPLEX STRUCTURAL ENGINEERING PROBLEMS

by

KAPIL DILIP PATKI

December 2015

Advisor: Dr. Christopher Douglas Eamon

Major: Civil Engineering

Degree: Doctor of Philosophy

Accurate probabilistic analysis of complex engineering problems with reasonable computational effort is a popular area of research in structural reliability analysis. For probabilistically complex problems such as those involving nonlinear FE analysis; traditional simulation methods often require unfeasibly great computational effort, while low-cost reliability index approaches may lack sufficient accuracy. This dissertation report addresses this issue by developing a simulation-based method referred to as Advanced Failure Sampling (FS).

In this research, …

Analysis And Suppression Of Engine Hood Vibrations Under Random Road Excitations, Hooman Farrokhzadeh

Wayne State University Theses

Vehicle designs and developments must meet safety legislations along with market demands. Safety regulations are mainly concerned with how a vehicle body performs in crashes, during which pedestrian collision is the one of the most important issues. When a vehicle strikes a pedestrian, its engine hood will most likely hit the head of the pedestrian, causing serious injuries. To reduce the severity of the injuries, along with market demands to improve vehicle fuel economy and performance, engineers have considered the design solution of reduction of the vehicle hood thickness (and hence its weight) and the use of advanced light materials. …

Statistical Approach To Design For Fall Prevention In Construction, Kyunghwan Kim

Wayne State University Theses

During the past decades, the construction industry has been considered as one of the most vulnerable field to work-related injuries and fatalities, and fall accidents are the leading causes accounting for about one-third of the total fatal injuries happened in construction. Furthermore, more than 30% of fall fatal cases occurred in the projects under $ 300K in Korea where construction workers' safety and health are not usually considered as top priorities because the contractors, who are normally small sized construction firms or self-employed, do not have safety budget to deal with construction workers' safety.

In this respect, this study focused …

Assessment Of Temporal And Spatial Alterations In Spinal Glial Reactivityand The Extent Of Cervical Spinal Axonal Injury In The Rat After Blast Overpressure, Heena S. Purkait

Wayne State University Theses

Blast induced neurotrauma (BINT) is the signature wound of veterans returning from various military operations. A substantial percentage of Operations Enduring Freedom (OEF) and Iraqi Freedom (OIF) veterans have reported to experience ongoing or new pain following their military service. Head (58%) and back (55%) have been the high prevailing locations of pain in these returning OIF and OEF veterans and the underlying pathomechanism of these conditions is yet to be understood. In the context of blast overpressure induced pathological changes, the fundamental question that still needs to be addressed is whether there are any underlying cellular injury changes the …

Advancement And Validation Of A Plug-In Hybrid Electric Vehicle Model Utilizing Experimental Data From Vehicle Testing, Kevin Lloyd Snyder

Wayne State University Theses

The objective of the research into modeling and simulation was to provide an iterative improvement to the Wayne State EcoCAR 2 team's math-based design tools for use in evaluating different outcomes based on hybrid powertrain architecture tweaks, controls code development and testing. This thesis includes the results of the team's work in the EcoCAR 2 competition for university student teams to create and test a plug-in hybrid electric vehicle for reducing petroleum oil consumption, pollutant emissions, and Green House Gas (GHG) emissions.

Plant model validations and advancements brought the vehicle plant model directionally closer to the actual vehicle's experimental data …

Fabrication And Characterization Of A Robust, Field- Deployable, Optical Sensor Designed To Detect Particles In Oils., Navya Pandreka

Wayne State University Theses

Some types of bacteria and fungus can use iron or non-ferrous metals for their metabolic process. Sulfate-reducing bacteria can corrode pipes in the oil industry and high-end machinery. Both aerobic and anaerobic bacteria often degrade fuel quality and cause fuel system corrosion or alter the chemical properties of the fluid. This causes significant economic damage and safety concerns. Therefore, there is a need for a system to continuously monitor fuel or lubricant oil for the presence of bacteria and fungus.

The main goal of this project was to develop a sensor that can detect bacteria and other ferrous and non-ferrous …

Developing An Automated Forecasting Framework For Predicting Operation Room Block Time, Azad Sadr Haghighi

Wayne State University Theses

Operating rooms are the most important part of the hospitals, since they have highest influence on financial state of the hospital. Because of high uncertainty in surgery cases demands and their durations, the scheduling of the surgeries becomes a very challenging and critical issue in hospitals. One of the most common approaches to overcome this uncertainty is applying block times which is the time intervals allocated to surgery groups in the hospital. Assigning sufficient amount of the time to each block, is very important, since overestimating lead to wasting resources and on the other hand underestimation causes the overtime staffing …

First-Principles Point Defect Models In Zr7ni10 And Zr2ni7 Binary Intermetallic Compounds And Their Implications In Nickel-Metal Hydride Batteries, Diana Felicia Wong

Wayne State University Theses

Zr-Ni-based alloys as nickel-metal hydride battery anode materials offer low-cost, flexible and tunable battery performance. Zr7Ni10 is an important secondary phase found in multi-phased AB2 Laves-phase-based metal hydride alloys, and the synergetic effect between the Zr-Ni and the Laves phases allows access to the high hydrogen storage of the Zr-Ni phases despite the lower absorption/desorption kinetics. Zr7Ni10 displays a small solubility window for Zr-rich compositions, while Zr2Ni7, with no solubility window, shows poor capacity with good kinetics. Stability of point defects within the crystal structure allows Zr7Ni10 to maintain the same structure at off-stoichiometric compositions, thus it is theorized that …

A Customer Choice Modeling Framework For Assortment Planning Of Configurable Products In Automotive Industry, Farah Dubaisi

Wayne State University Theses

Due to the increased competition in the auto industry, proliferation of the vehicle models and increased customer need for choice and customization, it has become more critical than ever to offer a variety of features and customization flexibility while at the same time restraining and, even better, cutting down the costs. Product complexity, in the automotive industry, can be measured by the size of the assortment offered, i.e., set of vehicle configurations a customer can choose from (e.g., for a given model of a brand). While complexity fosters growth with increased alignment of product characteristics and customer needs, it results …

Quantitative Brain Electrical Activity In The Initial Screening Of Mild Traumatic Brain Injuries After Blast, Chengpeng Zhou

Wayne State University Theses

ABSTRACT

QUANTITATIVE BRAIN ELECTRICAL ACTIVITY IN THE INITIAL SCREENING OF MILD TRAUMATIC BRAIN INJURIES AFTER BLAST

by

CHENGPENG ZHOU

August 2015

Advisor: Dr. John Michael Cavanaugh, Dr. Chaoyang Chen

Major: Biomedical Engineering

Degree: Master of Science

Objective: Quantitative electroencephalography (QEEG) has been reported to be sensitive in the diagnosis and measurement of mild traumatic brain injury (mTBI) in civilian setting and thus may be a promising tool in individuals who have been exposed to blast forces. Using a swine model, this study investigated EEG changes early after blast exposure. The purpose was to determine if QEEG can detect brain activity …

Model Based Process Analysis And Tool Development For Sustainable Electroplating Operations, Navdeep Bhadbhade

Wayne State University Theses

The electroplating industry has faced tremendous challenges in maintaining its economic competitiveness as well as improving its environmental performance in the global economy. In electroplating systems, waste generation from manufacturing lines has been always a serious concern, as waste emitted in different forms contains various hazardous and toxic chemicals. It is recognized that much of the generated waste is avoidable, and reduction of such avoidable waste could significantly reduce the consumption of chemicals, energy, and water. Proactive source reduction can improve not only environmental quality, but also economic performance. This type of source reduction, which could be called Proactive Pollution …

Evaluation Of Mems Fabricated Fractal Based Free Standing Scaffolds For The Purposes Of Developing A Brain Bioreactor, Brandy Broadbent

Wayne State University Theses

The brain is the most complex organ in the body due to the multiple cell types,

billions of tightly packed synapses, extracellular matrix, and intricate topography. Microelectrical-mechanical

fabrication techniques exhibit promise in the field of neuronal

tissue engineering because the shape is highly controllable and a variety of materials can

be used in creation of bioreactors. This work evaluates the ability of a free standing TiO2

coated fractal scaffold to support healthy neuronal growth. Also evaluated is the

propensity for the neurons to take advantage of the 3D growing surface without the use of

complex extracellular matrix factors over the …

Experimental Investigation On Combustion And Ionization During Cold Starting And Idling Of A Diesel Engine, Sahil Deodatta Sane

Wayne State University Theses

Diesel engine performance during cold starting is very crucial for smooth engine start at undesirable emission level. The development of cold start strategies that improve combustion stability relies mainly on the understanding of the combustion process during the cold starting. Even for modern diesel engines, the conditions during the cold start is far from normal operation characterized by large amount of unburned hydrocarbon emissions and long start to idling time. Thus, the use of an in-cylinder combustion sensor to measure the combustion quality during engine starting can significantly improve engine cold start control strategies. The ion current sensor has the …

Predictive Analytics For Disease Condition Of Patients In Emergency Department, Azade Tabaie

Wayne State University Theses

Emergency Departments (EDs) in hospitals are experiencing severe crowding and prolonged patient waiting times. The reported crowding in hospitals shows patients in hospital hallways, long waiting times and full occupancy of ED beds. ED crowding has several potential unfavorable effects including patients and staff frustration, lower patient satisfaction and poor health outcomes. The primary motivations behind this study are shortening the patients’ waiting time and improving patient satisfaction and level of care.

The very initial interaction between clinicians and a patient is recorded on nurse triage notes which contain details of the reason for patient’s visit including specific symptoms and …

The Study Of Ionization In A Military, Heavy-Duty, Diesel Engine, Steven Zielinski

Wayne State University Theses

This thesis is an investigation of ionization in a military, heavy-duty, diesel engine. Ionization is a phenomenon which occurs in both spark-ignited and diesel engines. During the reactions of combustion, charged molecules and electrons are produced. The current produced, ion current, from these charges can be measured. The measurement of ion current can serve as an in-cylinder diagnostic for closed-loop engine control strategies. In this work, a literature review was performed to survey previous work as it pertains to ionization in diesel engines. In addition, a detailed description and comparison of the HEUI injection system was made to HPCR. This …

Effect Of Impact Damage On Compression-Compression Fatigue Behavior Of Sandwich Composites, Ali M. Al-Sharif

Wayne State University Dissertations

The aim of this research work was to investigate the effect of impact damage on in-plane buckling and compression-compression fatigue behavior for a new sandwich structure made from E-glass/epoxy face sheets over end-grain balsa wood core. Low velocity impact tests were carried out using a drop-weight impact tower by impacting the sandwich beam at the center with energy level slightly higher than threshold energy level of 8.8 J. Edge-wise compression static tests were conducted for impacted and non-impacted samples to address energy absorption characteristics of these composites. Analytical and experimental investigations were carried out to measure critical buckling loads and …

Quantification Of Auto-Ignition In Diesel Engines, Umashankar M. Joshi

Wayne State University Dissertations

Efforts have been made previously by researchers to quantify the auto-ignition quality of fuels by calculating global activation energy using Arrhenius plots with data measured for the ignition delay period (ID). Large variation in the activation energy of fuels has been observed even for fuels with closer CN values. More recently, the activation energy values obtained by Kook et al in (2005) on an optical engine do not agree with data obtained in an identical metallic engine by Jayakumar using fuels of same CN.

The disparity in their results can be attributed to the differences in ignition delay (ID) and …