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Full-Text Articles in Engineering

Integrated Production And Distribution Problem With Single Perishable Product, Wennian Li Dec 2012

Integrated Production And Distribution Problem With Single Perishable Product, Wennian Li

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This dissertation investigated the extension of the Integrated Production and Distribution Scheduling Problem (IPDSPP) using a variety of perishable products, applying the JIP principle and make-to-order strategy to integrate the production and distribution schedules. A single perishable product with a constant lifetime after production was used in the model discussed here. The objective of the problem was to find the solution that results in minimal system total transportation costs while satisfying customer demand within a fixed time horizon. In the solution, the fleet size, vehicle route and distribution schedule, plant production batch size and schedule were determined simultaneously. This research …


Managing Elective And Non-Elective Case Assignments For An Operating Room Suite, Narges Hosseini Dec 2012

Managing Elective And Non-Elective Case Assignments For An Operating Room Suite, Narges Hosseini

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The success of operating room management depends on all levels of decision making, from strategic to tactical and operational decisions. One key decision in systems with block booking is to assign sufficient amount of block time to surgeons and surgery groups. While the typical method of block assignment identifies the share of surgery groups from OR times based on average of past usage, this method does not count for the difference between cost of under and overtime. One of the goals of this research is to develop a decision framework for block assignment. This work is presented in chapter two. …


Updated Force Model For Milling Nickel-Based Superalloys, Andrew Henderson Dec 2012

Updated Force Model For Milling Nickel-Based Superalloys, Andrew Henderson

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Nickel-based superalloys are commonly used in applications which require high strength and resistance to creep and oxidation in extreme conditions. All nickel-based superalloys are considered difficult to machine; however, cast gamma-prime-strengthened nickel-based superalloys are more difficult to machine than common nickel-based superalloys. Machining comprises a significant portion of manufacturing processes and with advancements in technology and material properties, the methods and models used must be adapted in order to keep pace.
In this research, correlations are made, using fundamental principles, between measurements made with on-machine touch probes and the cutting tool's wear state, those correlations are used in an adaptive …


Supply Chain Network Design: Risk-Averse Vs. Risk-Neutral Decision Making, Alireza Madadi Dec 2012

Supply Chain Network Design: Risk-Averse Vs. Risk-Neutral Decision Making, Alireza Madadi

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Recent events, such as the Heparin tragedy, highlight the necessity for designers and planners of supply chain networks to consider the risk of disruptions in spite of their low probability of occurrence. One effective way to hedge against supply chain network disruptions is to have a robustly designed supply chain network. This involves strategic decisions, such as choosing which markets to serve, which suppliers to source from, the location of plants, the types of facilities to use, and tactical decisions, such as production and capacity allocation. In this dissertation, we focus on models for designing supply chain networks that are …


A Process Analysis Of Engineering Problem Solving And Assessment Of Problem Solving Skills, Sarah Grigg Dec 2012

A Process Analysis Of Engineering Problem Solving And Assessment Of Problem Solving Skills, Sarah Grigg

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In the engineering profession, one of the most critical skills to possess is accurate and efficient problem solving. Thus, engineering educators should strive to help students develop skills needed to become competent problem solvers. In order to measure the development of skills, it is necessary to assess student performance, identify any deficiencies present in problem solving attempts, and identify trends in performance over time. Through iterative assessment using standard assessment metrics, researchers/instructors are able to track trends in problem solving performance across time, which can serve as a gauge of students' learning gains.
This research endeavor studies the problem solving …


Flow Behavior Modeling And Process Control Of Electrically-Assisted Forming (Eaf) For Sheet Metals In Uniaxial Tension, Joshua Jones Dec 2012

Flow Behavior Modeling And Process Control Of Electrically-Assisted Forming (Eaf) For Sheet Metals In Uniaxial Tension, Joshua Jones

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This work studies the influence of an applied electrical current on magnesium sheet metal and introduces models which are successful in predicting the deformation behavior (i.e. material flow stress, local material strain, and thermal response). Also, this work examined the theory of electroplasticity by studying prior proposed theories and by quantifying the prior theories potential for improved dislocation mobility. From this analysis, a single dominant mechanism is determined and the theory of electroplasticity is explained using this single mechanism. The theory discussed in this work is supported by experimental testing and microstructure analysis.
In addition to studying the exact electroplastic …


Thermo-Mechanical Modeling Of The Electrically-Assisted Manufacturing (Eam) Technique During Open Die Forging, Wesley Salandro Aug 2012

Thermo-Mechanical Modeling Of The Electrically-Assisted Manufacturing (Eam) Technique During Open Die Forging, Wesley Salandro

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This thesis contains all of the steps which allow the Electrically-Assisted Manufacturing (EAM) technique to be experimentally explored and analytically modeled for an electrically-assisted forging operation. Chapter 1 includes the problem statement, proposed solution, and literature reviews on EAM. Chapter 2 describes a thorough background on the EAM technique, highlights prior EAM research, and explains the research approach taken for this thesis. The coupled thermo-mechanical modeling strategy, along with the introduction of the Electroplastic Effect Coefficient (EEC) is provided in Chapter 3. Chapter 4 explains the two different approaches to determine the EEC profiles when modeling a particular metal. The …


Prognostic And Health-Management Oriented Fuel Cell Modeling And On-Line Supervisory System Development, Xian Zhang Aug 2012

Prognostic And Health-Management Oriented Fuel Cell Modeling And On-Line Supervisory System Development, Xian Zhang

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Of the fuel cells being studied, the proton exchange membrane fuel cell (PEMFC) is viewed as the most promising for transportation. Yet until today, the commercialization of the PEMFC has not been widespread in spite of its large expectation. Poor long term performances or durability, and high production and maintenance costs are the main reasons. For the final commercialization of fuel cells in the transportation field, durability issues must be addressed, while costs should be further brought down. At the same time, health-monitoring and prognosis techniques are of great significance in terms of scheduling condition-based maintenance (CBM) to minimize repair …


Districting And Dispatching Policies To Improve The Efficiency Of Emergency Medical Service (Ems) Systems, Damitha Bandara Aug 2012

Districting And Dispatching Policies To Improve The Efficiency Of Emergency Medical Service (Ems) Systems, Damitha Bandara

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The major focus of Emergency Medical Service (EMS) systems is to save lives and to minimize the
effects of emergency health incidents. The efficiency of the EMS systems is a major public concern. Thus,
over the past three decades a significant amount of research studies have been conducted to improve the performance
of EMS systems. The purpose of this study is also to improve the performance of EMS system.
The contribution of this research towards improving the performance of EMS systems is twofold. One area
is to implement optimal or near optimal dispatching strategies for EMS systems and the other …


Algebraic Approaches To Stochastic Optimization, Katherine Hastings May 2012

Algebraic Approaches To Stochastic Optimization, Katherine Hastings

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The dissertation presents algebraic approaches to the shortest path and maximum flow problems in stochastic networks. The goal of the stochastic shortest path problem is to find the distribution of the shortest path length, while the goal of the stochastic maximum flow problem is to find the distribution of the maximum flow value. In stochastic networks it is common to model arc values (lengths, capacities) as random variables. In this dissertation, we model arc values with discrete non-negative random variables and shows how each arc value can be represented as a polynomial. We then define two algebraic operations and use …


A Comprehensive Human Factors Analysis Of Off-Duty Motor Vehicle Crashes In The United States Military, Rebecca Iden May 2012

A Comprehensive Human Factors Analysis Of Off-Duty Motor Vehicle Crashes In The United States Military, Rebecca Iden

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Researchers have always had great interest in traffic safety and the phenomenon of motor vehicle crashes (MVCs). Though scores of service members are severely injured or killed in off-duty MVCs each year, few studies have addressed the MVC phenomenon within the military population and none have conducted a comprehensive evaluation of the causal factors associated with MVCs involving military personnel.
The main purpose of this dissertation was to gain a greater understanding of the causal factors associated with serious and fatal off-duty personal MVCs for military service members with the ultimate goal of preventing future losses. The HFACS-MVC framework was …


Research And Development Effort In Developing The Optimal Formulations For New Tablet Drugs, Zhe Li May 2012

Research And Development Effort In Developing The Optimal Formulations For New Tablet Drugs, Zhe Li

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Seeking the optimal pharmaceutical formulation is considered one of the most critical research components during the drug development stage. It is also an R&D effort incorporating design of experiments and optimization techniques, prior to scaling up a manufacturing process, to determine the optimal settings of ingredients so that the desirable performance of related pharmaceutical quality characteristics (QCs) specified by the Food and Drug Administration (FDA) can be achieved. It is widely believed that process scale-up potentially results in changes in ingredients and other pharmaceutical manufacturing aspects, including site, equipment, batch size and process, with the purpose of satisfying the clinical …


Extending Origami Technique To Fold Forming Of Sheet Metal Products, Ala Qattawi Jan 2012

Extending Origami Technique To Fold Forming Of Sheet Metal Products, Ala Qattawi

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This dissertation presents a scientific based approach for the analysis of folded sheet metal products. Such analysis initializes the examination in terms of topological exploration using set of graph modeling and traversal algorithms. The geometrical validity and optimization are followed by utilizing boundary representation and overlapping detection during a geometrical analysis stage, in this phase the optimization metrics are established to evaluate the unfolded sheet metal design in terms of its manufacturability and cost parameters, such as nesting efficiency, total welding cost, bend lines orientation, and maximum part extent, which aides in handling purposes. The proposed approach evaluates the design …