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 …

Specialized Inter-Particle Interaction Lbm For Patterned Superhydrophobic Surfaces, Amal Saeed Yagub

Wayne State University Dissertations

SPECIALIZED INTER-PARTICLE INTERACTION LBM FOR PATTERNED SUPERHYDROPHOBIC SURFACES

by

AMAL S. YAGUB

ABSTRACT:

Superhydrophobic surface characteristics are important in many industrial applications, ranging from the textile to the military. It was observed that surfaces fabricated with nano/micro roughness can manipulate the droplet contact angle, thus providing an opportunity to control the droplet wetting characteristics. The Shan and Chen (SC) lattice Boltzmann model (LBM) is a good numerical tool, which holds strong potentials to qualify for simulating droplets wettability. This is due to its realistic nature of droplet contact angle (CA) prediction on flat smooth surfaces. But SC-LBM was not able …

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, …

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 …

Formal Design Concept And Participant Behavior Analysis For Crowdsourcing Design, Jihoon Kim

Wayne State University Dissertations

Crowdsourcing has emerged as a new design resource for conceptual design process and multiple crowdsourcing services provide an opportunity for design idea collection and concept generation by crowds. However, few formal methods are available to extract and evaluate design concepts from the activities of the design crowd. Scarcity of information and non-guaranteed quality of contributions are often challenges to be tackled. To overcome the challenges, the research aims to answer how a system systematically extracts and represents the explicit or implicit hidden design concepts from crowdsourcing design activities and how crowdsourcing design activities of participants are captured as design information …

Biomechanical And Biological Evaluation Of A Model Of Post-Traumatic Osteoarthritis Following Noninvasive, Traumatic Rupture Of The Anterior Cruciate Ligament, Tristan Maerz

Wayne State University Dissertations

Post-traumatic osteoarthritis (PTOA) is a prevalent condition following rupture of the anterior cruciate ligament (ACL). While numerous animal models of PTOA exist, most are based on surgical disruption of a stabilizing structure. In the rat, surgical ACL transection is the most commonly employed model, but it may introduce confounding biological factors due to surgery. The purpose of this dissertation was to utilize the tibial compression model of ACL injury to induce a noninvasive ACL rupture in the rat. First, a biomechanical characterization of four different loading protocols was undertaken, and a high-speed, high-displacement protocol was deemed optimal for inducing a …

Frequency Domain Ultrasound Waveform Tomography Breast Imaging, Gursharan Singh Sandhu

Wayne State University Dissertations

Ultrasound tomography is an emerging modality for imaging breast tissue for the detection of disease. Using the principles of full waveform inversion, high-resolution quantitative sound speed and attenuation maps of the breast can be created. In this thesis, we introduce some basic principles of imaging breast disease and the formalism of sound wave propagation. We present numerical methods to model acoustic wave propagation as well methods to solve the corresponding inverse problem. Numerical simulations of sound speed and attenuation reconstructions are used to assess the efficacy of the algorithm. A careful review of the preprocessing techniques needed for the successful …

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 …

Frontiers In Operations Research For Overcoming Barriers To Vehicle Electrification, Mahyar Movahed Nejad

Wayne State University Dissertations

Electric vehicles (EVs) hold many promises including diversification of the transportation energy feedstock and reduction of greenhouse gas and other emissions. However, achieving large-scale adoption of EVs presents a number of challenges resulting from a current lack of supporting infrastructure and difficulties in overcoming technological barriers. This dissertation addresses some of these challenges by contributing to the advancement of theories in the areas of network optimization and mechanism design.

To increase the electric driving range of plug-in hybrid electric vehicles (PHEVs), we propose a powertrain energy management control system that exploits energy efficiency dif- ferences of the electric machine and …

Methodology For Validating Multi-Dimensional Engine Combustion Models And Fuel Surrogates Using An Optically Accessible Compression Ignition Engine, Xin Yu

Wayne State University Dissertations

In response to increasingly stringent engine emissions regulation, three dimensional in-cylinder combustion modeling is increasingly being used as a tool to optimize the combustion process and reduce the cost of experimental testing. Due to the complexity of the physical and chemical interactions involved in the in-cylinder combustion process, the engine combustion model consists of numerous sub-models developed under pre-defined initial and boundary conditions requiring further model calibration depending on different engine applications. Fuel surrogates, one of those sub-models developed for different combustion applications, may not capture all the behavior when applied to the varying temperature-pressure conditions present in a compression …

Quantifying Magnetic Moments And Susceptibilities Of Small Cylindrical And Spherical Objects In Mri, Ching-Yi Hsieh

Wayne State University Dissertations

Purpose: The purpose of this PhD work is to develop a method for accurately quantifying effective magnetic moments and susceptibility of either cylindrical or spherical-like small objects from magnetic resonance imaging (MRI). A standard 3D gradient echo sequence with only one echo time is intended for our approach to measure the effective magnetic moment of a given object of interest. For the quantification of the susceptibility in the cylindrical objects at different orientations, a standard 3D gradient echo sequence with only one or two echo times is needed.

Methods: Our method is to sum over complex MR signals around the …

Building Computing-As-A-Service Mobile Cloud System, Kun Wang

Wayne State University Dissertations

The last five years have witnessed the proliferation of smart mobile devices, the explosion of various mobile applications and the rapid adoption of cloud computing in business, governmental and educational IT deployment. There is also a growing trends of combining mobile computing and cloud computing as a new popular computing paradigm nowadays. This thesis envisions the future of mobile computing which is primarily affected by following three trends: First, servers in cloud equipped with high speed multi-core technology have been the main stream today. Meanwhile, ARM processor powered servers is growingly became popular recently and the virtualization on ARM systems …

Edge Fracture Prediction Of Dual Phase Steels With Consideration Of Microstructures, Ming Wen

Wayne State University Dissertations

In recent years, Advanced High Strength Steels (AHSS) have been used for the lightweight structural design and manufacturing in automotive industry. This class of sheet metals are prone to edge fracture during stamping production, and the fracture often occurs at much lower strain than that predicted based on the forming limit curves. The uncertainty in predicting edge fracture represents a great challenge in the application of AHSS. This dissertation is focused on the better understanding of edge fracture phenomenon through experimental observation and computer modeling with the consideration of microstructure effect.

In this dissertation, Hole Expansion (HE) test was used …

An Investigation Of The Relationship Between Axonal Injury, Biomarker Expression And Mechanical Response In A Rodent Head Impact Acceleration Model, Yan Li

Wayne State University Dissertations

In the United States 1.4 million people sustain traumatic brain injury (TBI) each year, resulting in 235,000 hospitalizations and 50,000 fatalities annually. Traumatic axonal injury (TAI) is a serious outcome of TBI that accounts for 40-50% of hospitalizations due to head injury and one third of the mortality due to TBI, and it is difficult to diagnose and evaluate. The purpose of this dissertation is to determine mechanical injury predictors for TAI and identify potential biomarkers to evaluate TAI.

In this dissertation, a modified Marmarou impact acceleration injury model was developed to allow the monitoring of velocity of the impactor …

Novel Incorportation Of Biomedical Engineering Algorithms (Bispectral Index Guided Or Anesthetic Concentration Guided) In Real-Time Decision Support To Prevent Intraoperative Awareness Using An Electronic Anesthesia Information Mananagement System, Amy Melanie Shanks

Wayne State University Dissertations

Background: Intraoperative awareness with explicit recall (AWR) is a feared complication of surgery that can lead to significant psychological distress. Several large prospective trials have been completed comparing two methods of monitoring anesthetic depth [minimum alveolar concentration (MAC) or electroencephalography (EEG) monitoring using the bispectral index (BIS)] for the prevention of AWR. However, these trials were conducted in high risk populations, limiting generalizability.

Research Hypothesis: Real-time decision support with Anesthesia Information Management System alerts based on a novel anesthetic concentration algorithm (incorporating the use of intravenous anesthetics) or an EEG-guided algorithm will reduce the known incidence of AWR.

Methods: First, …