Engineering Commons^™

Quantification Of Volatile Residuals In Polydioxanone By Gas Chromatography: Method Development, Validation And Implementation, Clayton Joseph Culbreath

All Theses

Bioresorbable polymers are increasingly utilized for implantable medical devices to avoid complications related to explant and/or long term responses to foreign materials. As with all polymeric materials, residual levels of unreacted monomer, and other volatiles, drastically affect the mechanical and chemical properties as well as the parameters required to process the material into a device. The 1,4-dioxane-2-one (PDO) monomer is a six membered ring that forms an ether-ester polymer via ring-opening polymerization (ROP) with intermediate absorption rate properties that are ideal for numerous implant situations. Developing devices using poly(1,4-dioxane-2-one) (PPDO, PDO, PDX, PPDX, or PDS) is complicated by residual levels …

Towards Structuring Smart Grid: Energy Scheduling, Parking Lot Allocation, And Charging Management, Mehdi Rahmani-Andebili

All Dissertations

Nowadays, the conventional power systems are being restructured and changed into smart grids to improve their reliability and efficiency, which brings about better social, economic, and environmental benefits. To build a smart grid, energy scheduling, energy management, parking lot allocation, and charging management of plug-in electric vehicles (PEVs) are important subjects that must be considered. Accordingly, in this dissertation, three problems in structuring a smart grid are investigated.

The first problem investigates energy scheduling of smart homes (SHs) to minimize daily energy consumption cost. The challenges of the problem include modeling the technical and economic constraints of the sources and …

A Real-Time Programmable Pulsatile Flow Pump For In Vitro Cardiovascular Experimentation, Rahul Raj Mechoor, Tyler Schmidt, Ethan Kung

Publications

Benchtop in vitro experiments are valuable tools for investigating the cardiovascular system and testing medical devices. Accurate reproduction of the physiologic flow waveforms at various anatomic locations is an important component of these experimental methods. This study discusses the design, construction, and testing of a low-cost and fully programmable pulsatile flow pump capable of continuously producing unlimited cycles of physiologic waveforms. It consists of a gear pump actuated by an AC servomotor and a feedback algorithm to achieve highly accurate reproduction of flow waveforms for flow rates up to 300 ml/s across a range of loading conditions. The iterative feedback …

Ultra Large Scale Manufacturing Challenges Of Silicon Carbide And Gallium Nitride Based Power Devices And Systems, Rajendra Singh, Amir A. Asif

Publications

The potential of wide band gap (WBG) semiconductors for manufacturing ultra-high performance power devices and systems is well known [1]. Historically, silicon carbide research is as old as is the discovery of transistors [2]. In recent years, significant progress has been made in reducing the bulk crystal defects. As a result, for niche applications some SiC and GaN products are currently in the market. However, silicon dominates the power devices and systems market. In an earlier publication [3] we pointed out that bulk crystal defects and process induced defects are still the major road blocks in creating a SiC and …

Obstacle Filtering Alogrithm For Control Of An Autonomous Road Vehicle In Public Highway Traffic, Qian Wang, Beshah Ayalew

Publications

This paper presents an obstacle filtering algorithm that mimics human driver-like grouping of objects within a model predictive control scheme for an autonomous road vehicle. In the algorithm, a time to collision criteria is first used as risk assessment indicator to filter the potentially dangerous obstacle object vehicles in the proximity of the autonomously controlled vehicle. Then, the filtered object vehicles with overlapping elliptical collision areas put into groups. A hyper elliptical boundary is regenerated to define an extended collision area for the group. To minimize conservatism, the parameters for the tightest hyper ellipse are determined by solving an optimization …

Fall 2016 - Volume 41, Number 1, Full Issue

The Professional Constructor

No abstract provided.

Capacity Building For Sustainable Workforce In The Construction Industry, Edelmiro F. Escamilla, Mohammadreza Ostadalimakhmalbaf

The Professional Constructor

Research has shown that the construction industry will face workforce shortages that will increase delivery cost and completion time. The purpose of this paper is to first identify and synthesize the fundamental factors impacting recruitment and retention of the potential construction workforce. A qualitative approach was employed in order to collect and synthesize known factors related to workforce development and capacity building for the construction industry. The paper then presents a conceptual framework for conducting research on capacity generation of a sustainable construction workforce—by considering the impact of family unit and cultural values, career path perceptions, higher educational attainment, and …

Comparing Owner Perceptions Vs. Performance Reality On Construction Management At Risk Public School Projects, Noel Carpenter, Dennis C. Bausman

The Professional Constructor

Over the past decade construction expenditures for education have reached approximately $350 billion with $195 billion of that total spent on K-12 public schools. Public funding through state and local taxes is the primary source of support for construction and school districts are charged with spending these dollars wisely. Within the confines of procurement statutes school districts must select a delivery method that best suits their needs. Two commonly used delivery methods are Design-Bid-Build and Construction Manager at Risk (CM at Risk). This paper examines qualitative and quantitative data collected from one hundred thirty-seven new K-12 school projects constructed in …

Free Fall Of Self-Consolidating Concrete In Walls Three Meters High, Donald J. Phillippi, Katie Loughmiller, Ray Buyle, Michael Cesena

The Professional Constructor

Self-consolidating concrete, (SCC) is a highly flowable, non-segregating concrete that allows for concrete placement without vibration or external consolidation. SCC also allows rapid concrete placement with reduced labor costs, resulting in vastly improved concrete surface finishes and architectural applications (RMCAO 2009). To accomplish SCC, the concrete industry has developed improvements in high-range water reducer admixtures for flowability and viscosity-modifying admixtures for stability. The current project investigated six specimens, which provided an evaluation of SCC allowed to free fall 3 m (10 ft) that filled wall formwork with different inclinations and amounts of steel reinforcement. The purpose of the investigation was …

Integration Of Structural Health Monitoring And Intelligent Transportation Systems For Bridge Condition Assessment: Current Status And Future Direction, Sakib Mahmud Khan, Sez Atamturktur, Mashrur Chowdhury, Mizanur Rahman

Publications

Recent catastrophic bridge failures clearly indicate the urgent need for improving interval-based bridge inspection procedures that are qualitative and subjective in nature. Structural Health Monitoring (SHM) can mitigate the deficiencies of interval-based inspection techniques and provide real-time diagnostic information regarding the bridge structural health. SHM is not flawless however; the variability in the vehicle characteristics and traffic operational conditions makes it prone to false diagnosis. Recent advancements in the integration of SHM with intelligent transportation systems (ITS) demonstrate the successful use of ITS devices (e.g., traffic cameras, traffic detectors) in the analysis of bridge responses to multimodal traffic with varying …

Energy Consumption Modeling And Analyses In Automotive Manufacturing Plant, Lujia Feng, Laine Mears

Publications

Manufacturing plants energy consumption accounts for a large share in world energy usage. Energy consumption modeling and analyses are widely studied to understand how and where the energy is used inside of the plants. However, a systematic energy modeling approach is seldom studied to describe the holistic energy in the plants. Especially using layers of models to share information and guide the next step modeling is rarely studied. In this paper, a manufacturing system temporal and organizational framework was used to guide the systematic energy modeling approach. Various levels of models were established and tested in an automotive manufacturing plant …

Effective And Economical Content Delivery And Storage Strategies For Cloud Systems, Yuhua Lin

All Dissertations

Cloud computing has proved to be an effective infrastructure to host various applications and provide reliable and stable services. Content delivery and storage are two main services provided by the cloud. A high-performance cloud can reduce the cost of both cloud providers and customers, while providing high application performance to cloud clients. Thus, the performance of such cloud-based services is closely related to three issues. First, when delivering contents from the cloud to users or transferring contents between cloud datacenters, it is important to reduce the payment costs and transmission time. Second, when transferring contents between cloud datacenters, it is …

Rare Earth Emissions From Polyethylene Terephthalate Fiber, Joshua Jenkins Furtick

All Theses

Rare earth-polymer blends can be useful in many applications including safety, security, displays, and novelty. Polyester, specifically polyethylene terephthalate, is a ubiquitous material in the world today and offers many opportunities for the usefulness of visible light rare earth emissions.

In this work we have attempted to incorporate rare earth complexes with polyester yarn using various methods including coating, extrusion, and dyeing, with the latter having the most success. Nanoparticles were used initially for these experiments, however certain limitations of the particles could not be overcome, for example the size of the particles and the incompatibility of the inorganic matrix …

Development And Initial Validation Of A Surgical Instrument For In Situ Mechanical Characterization Of Surgical Mesh-Tissue Composites, Jorge Ivan Hernandez Sanchez

All Theses

Approximately 5 million Americans have an abdominal wall hernia, and over 700,000 undergo surgical procedures every year to treat them. Surgical procedures have evolved with the goal of preventing recurrences, leading to the current gold standard of treatment: hernia repair with mesh. Hernia repair with mesh consists on augmenting the weakened abdominal wall by implanting a synthetic or biological mesh. Although the adoption of hernia repair with mesh has improved outcomes, recurrence from primary repair procedures with large incisions (>10 cm) remains an alarming 32%.

The wide variety of implanted surgical mesh (materials, structure) and surgical variability (attachment method, …

Autologous Protein Solution Exhibits Potential To Mitigate Osteoarthritis (Oa) Progression In A Human Explant Co-Culture Model, Kathleen Emily Steckbeck

All Theses

Osteoarthritis (OA) is a debilitating and painful disease that affects upwards of one in every eight adults1,2. OA influences the entire joint, but is traditionally characterized by cartilage degradation3. OA is a multifactorial disease with genetic, biological, and biochemical consideration, but there has been a recent shift in scientific opinion that the pathological progression of OA stems from an inflammatory milieu produced by the feed-forward progressive pathway as evidenced by simultaneous cartilage and synovium co-culture4–7. Autologous protein solution (APS) poses as an intriguing potential OA therapy by possessing a high anti-inflammatory and anabolic mediator concentration profile that could potentially mitigate …

Supervisory Control Optimization For A Series Hybrid Electric Vehicle With Consideration Of Battery Thermal Management And Aging, Xueyu Zhang

All Dissertations

This dissertation integrates battery thermal management and aging into the supervisory control optimization for a heavy-duty series hybrid electric vehicle (HEV). The framework for multi-objective optimization relies on novel implementation of the Dynamic Programing algorithm, and predictive models of critical phenomena. Electrochemistry based battery aging model is integrated into the framework to assesses the battery aging rate by considering instantaneous lithium ion (Li+) surface concentration rather than average concentration. This creates a large state-action space. Therefore, the computational effort required to solve a Deterministic or Stochastic Dynamic Programming becomes prohibitively intense, and a neuro-dynamic programming approach is proposed to remove …

Towards An Efficient Cloud Computing System: Data Management, Resource Allocation And Job Scheduling, Jinwei Liu

All Dissertations

Cloud computing is an emerging technology in distributed computing, and it has proved to be an effective infrastructure to provide services to users. Cloud is developing day by day and faces many challenges. One of challenges is to build cost-effective data management system that can ensure high data availability while maintaining consistency. Another challenge in cloud is efficient resource allocation which ensures high resource utilization and high SLO availability. Scheduling, referring to a set of policies to control the order of the work to be performed by a computer system, for high throughput is another challenge. In this dissertation, we …

Optimizing Virtual Resource Management In Cloud Datacenters, Liuhua Chen

All Dissertations

Datacenter clouds (e.g., Microsoft's Azure, Google's App Engine, and Amazon's EC2) are emerging as a popular infrastructure for computing and storage due to their high scalability and elasticity. More and more companies and organizations shift their services (e.g., online social networks, Dropbox file hosting) to clouds to avoid large capital expenditures. Cloud systems employ virtualization technology to provide resources in physical machines (PMs) in the form of virtual machines (VMs). Users create VMs deployed on the cloud and each VM consumes resources (e.g., CPU, memory and bandwidth) from its host PM. Cloud providers supply services by signing Service Level Agreement …

Development Of A New Multimodal Membrane Adsorber And Its Application In Chromatographic Bioseparations, Juan Wang

All Dissertations

This dissertation presents work on the design and synthesis of a new membrane chromatography material, the description of its protein binding behavior using a thermodynamic adsorption isotherm model, and the application of the new membrane material in biologics downstream recovery and purification processes. As protein titers continue to increase dramatically in upstream biomanufacturing, innovations in downstream purification are not keeping pace, resulting in manufacturing capacity constraints and high production costs. Chromatography is the key unit operation used in several steps of the downstream purification platform. Traditional resin bead chromatography, while effective and reliable for isolation and purification of proteins, limits …

Optimization Techniques For Modern Power Systems Planning, Operation And Control, Karthikeyan Balasubramaniam

All Dissertations

Recent developments in computing, communication and improvements in optimization techniques have piqued interest in improving the current operational practices and in addressing the challenges of future power grids. This dissertation leverages these new developments for improved quasi-static analysis of power systems for applications in power system planning, operation and control.

The premise of much of the work presented in this dissertation centers around development of better mathematical modeling for optimization problems which are then used to solve current and future challenges of power grid. To this end, the models developed in this research work contributes to the area of renewable …

Engineering Xylose Utilization In Yarrowia Lipolytica By Understanding Its Cryptic Xylose Pathway, Gabriel M. Rodriguez, Murtaza Shabbir Hussain, Lauren Gambill, Difeng Gao, Allison Yaguchi, Mark Blenner

Publications

Background

The oleaginous yeast, Yarrowia lipolytica, has been utilized as an industrial host for about 60 years for various applications. Recently, the metabolic engineering of this host has become increasingly popular due to its ability to accumulate lipids as well as improvements made toward developing new genetic tools. Y. lipolytica can robustly metabolize glucose, glycerol, and even different lipid classes. However, little is known about its xylose metabolizing capability. Given the desirability of having a robust xylose utilizing strain of Y. lipolytica, we performed a comprehensive investigation and elucidation of the existing components of its xylose metabolic pathway. …

Transformative Role Of Photovoltaics In Phasing Out Alternating Current Based Grid By Local Dc Power Networks For Sustainable Global Economic Growth, Rajendra Singh, Amir A. Asif, Ganesh K. Venayagamoorthy

Publications

For sustainable global economic growth, eradication of global energy poverty and addressing climate challenges, free fuel based solar and wind energy sources are the only viable solution for electricity generation. Due to inherent advantages, photovoltaics has emerged as the major source of electrical power. Local generation of direct current (DC) power by PV and the use of batteries for storing electrical power have the potential of transforming global electricity infrastructure to address the problems faced by alternating current (AC) based centralized power generation and long haul transmission and distribution.

Energy, Economy, And Environment Analysis And Optimization On Manufacturing Plant Energy Supply System, Lujia Feng, Laine Mears, Cleveland Beaufort, Joerg Schulte

Publications

Increasing attention has recently been drawn to energy consumption in manufacturing plants. Facing the challenges from reducing emissions coupled with rising raw material prices and energy costs, manufacturers are trying to balance the energy usage strategy among the total energy consumption, economy, and environment, which can be self-conflicting at times. In this paper, energy systems in manufacturing environments are reviewed, and the current status of onsite energy system and renewable energy usage are discussed. Single objective and multicriteria optimization approaches are effectively formulated for making the best use of energy delivered to the production processes. Energy supply operation suggestions based …

Enrichment Of Diluted Cell Populations From Large Sample Volumes Using 3d Carbon-Electrode Dielectrophoresis, Monsur Islam, Rucha Natu, Maria Fernanda Larraga-Martinez, Rodrigo Martinez-Duarte

Publications

Here, we report on an enrichment protocol using carbon electrodedielectrophoresis to isolate and purify a targeted cell population from sample volumes up to 4 ml. We aim at trapping, washing, and recovering an enriched cell fraction that will facilitate downstream analysis. We used an increasingly diluted sample of yeast, 106–102 cells/ml, to demonstrate the isolation and enrichment of few cells at increasing flow rates. A maximum average enrichment of 154.2 ± 23.7 times was achieved when the sample flow rate was 10 μl/min and yeast cells were suspended in low electrically conductive media that maximizes dielectrophoresis trapping. A COMSOL …

Cost Estimation Model For Pan Based Carbon Fiber Manufacturing Process, Amaninder Singh Gill, Darian Visotsky, Laine Mears, Joshua D. Summers

Publications

A polyacrilonitrile (PAN) based carbon fiber manufacturing cost estimation model driven by weight is presented in this study. One of the biggest limiting factors in the large scale use of carbon fiber (CF) in manufacturing is its high cost. The costs involved in manufacturing the carbon fiber have been formalized into a cost model in order to facilitate the understanding of these factors. This can play a key role in manufacturing CF in a cost effective method. This cost model accounts for the fixed and variable costs involved in all stages of manufacturing, in addition to accounting for price elasticity.

Assessing The Advantages Of Using Square Wave Signals For Particle Trapping In Carbon-Electrode Dielectrophoresis, Guillermo Contreras-Dávila, Jose I. Gomez-Quiñones, Victor H. Pérez-González, Rodrigo Martinez-Duarte

Publications

Here we present an improvement on the trapping efficiency of 3D carbon electrode Dielectrophoresis (carbonDEP) by using alternative signal geometries to the more traditional sine used to stimulate the electrodes. In particular, a square waveform is used. Theoretical analysis was based on the Root Mean Square (RMS) values and the Fourier Series Expansion of these signals. Computational modeling was performed to calculate the DEP force generated by the two signal waveforms and allowed for direct comparison. The trapping efficiency between square and sine signals was then determined experimentally. Given the same experiment characteristics, the use of square signals allows for …

Synthesis Of Tungsten Carbide From Bacterial Cellulose, Monsur Islam, Rodrigo Martinez-Duarte

Publications

Here we present preliminary experiments for the synthesis of carbide material using bacterial cellulose as carbon source. We used bacteria cellulose available as Nata de Coco and infiltrated it with tungsten trioxide (WO₃) nanoparticles. This composite was heat treated at 1300 °C in nitrogen atmosphere. The XRD pattern confirms the synthesis of tungsten carbide (WC) in the carbonaceous material, though a significant amount of metallic tungsten remained unreacted. SEM images shows that WC particles are present only at the surface of the carbon, which may be a consequence of improper infiltration or collapse of carbon matrix during heat …

Synthesis Of Titanium Oxycarbide Through Carbothermal Reduction Of Titanium Dioxide Nanoparticles And Renewable Biopolymers, Joshua Paul Flach, Paulo Henrique Figuereido De Lima, Joshua Craig Sparks, Monsur Islam, Rodrigo Martinez-Duarte

Publications

The goal of this is study is to explore the feasibility of a sustainable method of titanium oxycarbide synthesis through carbothermal reduction of a biopolymer composite. The reaction was studied at different temperatures in vacuum environments and at multiple TiO₂:C ratios in order to determine how these parameters affect the formation of titanium oxycarbide. The results indicate that both the heat treatment and the carbon ratios have a significant impact on the O/C ratio, and therefore, molecular composition and crystal structure of the titanium oxycarbide. The use of renewable biopolymers as a carbon source in the synthesis of …

Towards Additive Manufacturing Of Tungsten Carbide Using Renewable Resources, Monsur Islam, Rodrigo Martinez-Duarte

Publications

Here we present preliminary results towards additive manufacturing of carbides. A biopolymer-metal oxide gel composite composed of iota-carrageenan, chitin and tungsten trioxide (WO₃) was shaped and heat treated in order to obtain carbide structures. Upon heat treatment of this composite above 900 °C, a porous structure of tungsten carbide (WC) was obtained. The synthesis mechanism of WC was estimated using the result from XRD characterization. The synthesized WC was characterized with SEM, TEM and nitrogen absorption-desorption to investigate the morphology, particle size and pore size distribution. The carbonaceous materials retained the original shape. The ongoing work is on …

3d Carbon-Electrode Dielectrophoresis For Enrichment Of A Small Cell Population From A Large Sample Volume, Monsur Islam, Rucha Natu, Maria Fernanda Larraga-Martinez, Guillermo Contreras-Dávila, Rodrigo Martinez-Duarte

Publications

Isolation and enrichment of cells from a diluted sample is necessary for different clinical applications. Here we have demonstrated the use of 3D carbon electrode dielectrophoresis (DEP) to process a diluted yeast sample featuring concentration as low as 102 cells/ml. The yeast cells in the sample were first trapped on carbon electrodes by implementing positive DEP force and then released and concentrated in a small volume of clean buffer. The maximum limit of the cell trapping for our device was found to be around 4000 cells. Using 10 µl/min, an enrichment of 154.2 ± 23.7 folds was achieved, where sample …