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Development Of Conjugate Heat Transfer Capability To An Unstructured Flow Solver - U2ncle, Qingluan Xue

Theses and Dissertations

A precise prediction of the heat loads in metal materials in contact with the hot gas is an increasingly demanding problem in the design phase of the complex cooling schemes in the modern turbine engines. The coupled calculation of the fluid flow and the heat transfer is a promising approach as heat transfer coefficients are not necessary in the calculation and the heat transfer itself is part of the calculation and can be derived from local heat fluxes. Therefore, it is useful to incorporate an appropriate scheme for directly coupled heat transfer computations (conjugate heat transfer), capable of handling complex …

2005-12-10 Minutes & Appendices, Longwood University

Board of Visitors Meeting Minutes 1964-

No abstract provided.

Transport Rate-Based Model For Overland Flow And Solute Transport: Parameter Estimation And Process Simulation, Zhi Qiang Deng, João L.M.P. De Lima, Vijay P. Singh

Faculty Publications

A one-dimensional mathematical model, termed a transport rate-based model, is developed for solute transport over infiltrating soil slopes under constant rainfall and declining sources. The model is comprised of (1) the kinematic-wave equation for overland flow, (2) a transport rate-based advection equation for overland solute transport, (3) a moment-based method for estimation of the parameters involved in the flow and solute transport equations, and (4) a semi-Lagrangian algorithm for numerical solution of the solute transport equation. Data from a single soil flume experiment under constant rainfall established the proof-of-concept for this new model. Sodium chloride was applied to the soil …

Finite Element Simulations Of Three-Dimensional Microstructurally Small Fatigue Crack Growth In 7075 Aluminum Alloy Using Crystal Plasticity Theory, Stephen R (Stephen Riley) Johnston

Theses and Dissertations

This thesis discusses plasticity-induced crack closure based finite element simulations of small fatigue cracks in three dimensions utilizing crystal plasticity theory. Previously, modeling has been performed in two dimensions using a double-slip crystal plasticity material model. The goal of this work is to extend that research using a full three-dimensional FCC crystal plasticity material model implementation that accounts for all twelve FCC slip systems. Discussions of Python scripts that were written to perform analyses with the commercial finite element code ABAQUS are given. A detailed description of the modeling methodology is presented along with results for single crystals and bicrystals. …

The Development Of A Methodology For Assessing Industrial Workstations Using Computer-Aided Ergonomics And Digital Human Models, Jinyan Du

Theses and Dissertations

This study examined an existing industrial workstation at an automobile assembly plant using computer aided ergonomics and digital human models. The purpose of this evaluation was the development of a methodology useful for evaluating workstations to identify potential design issues that could result in musculoskeletal injury in a real work environment. An ergonomic risk assessment was conducted on a lifting task while being performed both manually and using an assist device. JACK digital human modeling and ergonomics software were used to conduct a computer-based ergonomic analysis. Four analysis tools in JACK (static strength analysis, rapid upper limb assessment, metabolic energy …

Evaluation Of Chitosan Gelatin Complex Scaffolds For Articular Cartilage Tissue Engineering, Harshal Prabhakar Mahajan

Theses and Dissertations

In search of better scaffolding materials for in vitro culture of chondrocytes, the combination of chitosan (similar to glycosoaminoglycans) and gelatin (denatured collagen) was tested due to its resemblance to cartilage extra-cellular matrix (ECM). Porous scaffolds were fabricated from chitosan gelatin blends (1:1, 2:1, and 3:1). The response of chondrocytes to them was evaluated from the amount of sulphated GAG and collagen type 2 secreted after 3 and 5 weeks. The effect due to static (transwell inserts) and dynamic (rotating bioreactor) culture methods was analyzed. Results indicate that 1:1 chitosan gelatin blends showed the best chondro-conductive potential. The rotating bioreactor …

The Use Of Compression Precracking Constant Amplitude (Cpca) Test Method To Obtain Near-Threshold Fatigue Crack Growth Behavior In Aa7075-T7351, Dustin Henry Mcknight

Theses and Dissertations

Traditionally, pre-cracking has been performed under tension-tension loading, followed by a load reduction scheme to obtain fatigue crack growth rate data in the near threshold regime. These data have been shown to exhibit load history effects due to remote crack closure. An alternative test method has been developed to minimize these load history effects. This test procedure uses compression pre-cracking to initiate a crack, followed by constant amplitude loading to grow the crack to failure. Compression-compression (C-C) loading as a means of forming a starter crack for fatigue crack growth is a relatively new concept. Cracks grown under C-C loading …

Fast Reconfiguration Algorithm Development For Shipboard Power Systems, Yan Huang

Theses and Dissertations

Todays protection schemes for shipboard applications, such as the zone-based differential protection, are efficient, fast, and reliable for fault detection. However, these protection schemes do not consider the system stability or power balance problems that occur with fault isolation and the system reconfiguration. This thesis focuses on developing the extended protection function including the fast reconfiguration function that intends to maintain the power balance of the unfaulted subsystem. Graph theory is utilized to represent the shipboard power system topology in matrices, and matrix operations are developed to represent the corresponding power system topology change and evaluate the outcome of the …

Fatigue Crack Growth Under Residual Stresses Around Holes, Ramesh Nagaralu

Theses and Dissertations

Compressive residual stresses induced by tensile overloads, compressive under loads, or by a cold-expansion process in specimens containing a circular hole and their influence on subsequent fatigue crack growth in aluminum alloys are studied. The finite element method is used to calculate residual stresses. The superposition method, which uses crack-tip stress intensity factors for cases involving remote loading and residual stresses, is used to calculate crack growth life for three kinds of tests from the literature: (1) fatigue of a circular hole specimen after an overload or under load, (2) single crack growing from a circular hole after a severe …

Work Replication: A Communication Optimization For Loci, Krunal Navinchandra Soni

Theses and Dissertations

For distributed memory architectures, communication cost is a significant source of overhead in parallel scientific applications. Many proposed communication optimizations duplicate the behavior of well-written hand-tuned parallel code. Because of continuous changes in architectural components, these types of low-level optimizations are not always effective. This thesis seeks to develop a high-level optimization of work replication in which computations are replicated to minimize communications. There exist performance trade-offs between computation cost and communication cost because of work replication. Due to these trade-offs, it is required to determine which computations should be replicated to improve overall performance. This research presents the development …

3d Wavelet-Based Algorithms For The Compression Of Geoscience Data, Justin Thomas Rucker

Theses and Dissertations

Geoscience applications generate large datasets; thus, compression is necessary to facilitate the storage and transmission of geoscience data. One focus is on the coding of hyperspectral imagery and the prominent JPEG2000 standard. Certain aspects of the encoder, such as rate-allocation between bands and spectral decorrelation, are not covered by the JPEG2000 standard. This thesis investigates the performance of several JPEG2000 encoding strategies. Additionally, a relatively low-complexity 3D embedded wavelet-based coder, 3D-tarp, is proposed for the compression of geoscience data. 3D-tarp employs an explicit estimate of the probability of coefficient significance to drive a nonadaptive arithmetic coder, resulting in a simple …

A Micro-Cooling, Heating, And Power (M-Chp) Instructional Module, Jason Ryan Oliver

Theses and Dissertations

Cooling, Heating, and Power (CHP) is an emerging category of energy systems consisting of power generation equipment coupled with thermally activated components. The application of CHP systems to residential and small commercial buildings is known as micro-CHP (m-CHP). This instructional module has been developed to introduce engineering students to m-CHP. In the typical engineering curriculum, a number of courses could contain topics related to m-CHP. Thermodynamics, heat transfer, HVAC, heat and power, thermal systems design, and alternate energy systems courses are appropriate m-CHP topics. The types of material and level of analysis for this range of courses vary. In thermodynamics …

A Study On The Split Delivery Vehicle Routing Problem, Kai Liu

Theses and Dissertations

This dissertation examines the Split Delivery Vehicle Routing Problem (SDVRP), a relaxed version of classical capacitated vehicle routing problem (CVRP) in which the demand of any client can be split among the vehicles that visit it. We study both scenarios of the SDVRP in this dissertation. For the SDVRP with a fixed number of the vehicles, we provide a Two-Stage algorithm. This approach is a cutting-plane based exact method called Two-Stage algorithm in which the SDVRP is decomposed into two stages of clustering and routing. At the first stage, an assignment problem is solved to obtain some clusters that cover …

Adjoint-Based Error Estimation And Grid Adaptation For Functional Outputs From Cfd Simulations, Ravishankar Balasubramanian

Theses and Dissertations

This study seeks to reduce the degree of uncertainty that often arises in computational fluid dynamics simulations about the computed accuracy of functional outputs. An error estimation methodology based on discrete adjoint sensitivity analysis is developed to provide a quantitative measure of the error in computed outputs. The developed procedure relates the local residual errors to the global error in output function via adjoint variables as weight functions. The three major steps in the error estimation methodology are: (1) development of adjoint sensitivity analysis capabilities; (2) development of an efficient error estimation procedure; (3) implementation of an output-based grid adaptive …

An Adaptive Wireless Lan Mac Scheme To Achieve Maximum Throughput And Service Differentiation, Wei Zha

Theses and Dissertations

With the explosive deployment of wireless LAN technology in the past few years and increasing demand on multimedia applications, the efficient utilization of the precious wireless radio link resources and support of Quality of Service (QoS) in WLANs has become a prominent research issue. In this thesis, an adaptive p-persistent based I 802.11 MAC scheme in WLANs has been proposed. The proposed scheme can maximize the total channel throughput, and also provide service differentiation among multiple traffic classes. This is achieved by updating the transmission probabilities for the stations that compete for transmissions in a WLAN, adaptively based on the …

An Investigation Of Firms' Earnings Management Practices Around Product Recalls, Zeeshan Ahmed

Theses and Dissertations

This study investigates the earnings management practices of firms around product recalls. In recent years, the management of earnings around firm-specific events has received considerable attention in the finance and accounting literature. New equity issues, mergers and acquisitions, share repurchases, and management buyouts are some events around which at least some firms have been shown to manage their earnings to achieve managements? objectives. Product recalls offer yet another interesting occasion when managers have incentives to cover up the true financial performance of their firms and mislead investors. In order to determine whether firms announcing product recalls manage earnings more aggressively …

An Investigation Of The Performance In College Algebra Of Students Who Passed The Summer Developmental Program At Mississippi State University, Martha Hall Pratt

Theses and Dissertations

At Mississippi State University (MSU), students who do not meet full admission requirements may enroll in the Summer Developmental Program (SDP). During this ten-week summer program, students take four developmental courses to prepare them for college-level courses. MA 0003 Developmental Mathematics is the course designed to prepare these students for MA 1313 College Algebra. In addition, the Department of Mathematics and Statistics at MSU offers MA 0103 Intermediate Algebra to prepare students for MA 1313 College Algebra. The purpose of this study was to determine (a) whether there were correlations between student grades in MA 0003, MA 0103, and MA …

Approximate Methods For Solving Flowshop Problems, Pramod Jain

Theses and Dissertations

The flow shop scheduling problem is a classical combinatorial problem being studied for years. The focus of this research is to study two variants of the flow shop scheduling problem in order to minimize makespan by scheduling n jobs on m machines. A solution approach is developed for the modified flow shop problem with due dates and release times. This algorithm is an attempt to contribute to the limited literature for the problem. Another tabu search-based solution approach is developed to solve the classical flow shop scheduling problem. This meta-heuristic (called 3XTS) allows an efficient search of the neighboring solutions …

Automatic Cad Model Processing For Downstream Applications, Paresh S. Patel

Theses and Dissertations

Computer Aided Design (CAD) models often need to be processed due to data translation issues and requirements of the downstream applications like computational field simulation, rapid rototyping, computer graphics,computational manufacturing, and real-time rendering before they can be used. Automatic CAD model processing tools can significantly reduce the amount of time and cost associated with the manual processing.In this dissertaion, automated topology generation and feature removal techniques are developed to prepare suitable models with mimunum user interaction. A topology generation algorithm, commonly known as CAD repairing/healing, is presented to detect commonly found geometrical and topological issues like cracks, gaps, overlaps, intersections, …

Design Optimization Of A Parallel Hybrid Powertrain Using Derivative-Free Algorithms, Sachin Kumar Porandla

Theses and Dissertations

A Hybrid Electric Vehicle (HEV) is a complex electro-mechanical-chemical system that involves two or more energy sources. The inherent advantages of HEVs are their increased fuel economy, reduced harmful emissions and better vehicle performance. The extent of improvement in fuel economy and vehicle performance greatly depends on selecting optimal component sizes. The complex interaction between the various components makes it difficult to size specific components manually or analytically. So, simulation-based multi-variable design optimization is a possible solution for such kind of system level design problems. The multi-modal, noisy and discontinuous nature of the Hybrid Vehicle design requires the use of …

Design And Evaluation Of A Large Scale Aerosol Generator, Tracy Kristina Hogancamp

Theses and Dissertations

The Diagnostic Instrumentation and Analysis Laboratory (DIAL) at Mississippi State University was awarded a project to study the feasibility of measuring particulate matter downstream of a high efficiency particulate air (HEPA) filter by testing commercially available equipment used to monitor the downstream side of a HEPA filter. In order to perform the work required for this project, a test stand to accommodate a 12? x 12? x 11.5? HEPA filter with a rated flow of 250 standard cubic feet per minute (scfm) was constructed. The test stand required an aerosol generator capable of producing a mass loading rate of 30 …

Development Of A Supersonic Wind Tunnel Rapid Real-Time Data Acquisition And Control System, Ndubuisi Emmanuel Okoro

Theses and Dissertations

As a part of the revitalization of the supersonic wind tunnel maintained by the Aerospace Engineering Department of Mississippi State University, a new data acquisition and control system became incumbent. Previous data acquisition and control systems used in the operation of the supersonic wind tunnel made use of now outdated hardware and functioned with two central processing units; one processor was used for recording system response, while the other monitored and controlled the tunnel. A new system is required to provide adequate rapid real-time control, along with rapid acquisition of raw tunnel feedback or response data and tunnel pressure data …

Evaluation Of Hatchery And Growout Factors For The Successful Production And Stocking Of Juvenile Gulf Coast Walleye, Justin L. Wilkens

Theses and Dissertations

Temperature-dependent weight gain of Gulf coast and northern strain walleye Sander vitreus fingerlings was determined by rearing fish in flow-through aquaria at different water temperatures (range 15-32°C). Maximum growth of Gulf coast and northern strain walleye occurred between 20 and 26°C, and weight gain of northern walleye exceeded that of the Gulf coast strain by 1.5 times. An acclimated chronic exposure method to assess upper thermal limits determined that walleye survived 35, 9, and 1 days at 33, 34, and 35°C, respectively. A post pond-rearing feed-training practice (21 d) at a mean density of 6,290 ± 1,247 fish/m3 using formulated …

Combining Static Analysis And Dynamic Learning To Build Context Sensitive Models Of Program Behavior, Zhen Liu

Theses and Dissertations

This dissertation describes a family of models of program behavior, the Hybrid Push Down Automata (HPDA) that can be acquired using a combination of static analysis and dynamic learning in order to take advantage of the strengths of both. Static analysis is used to acquire a base model of all behavior defined in the binary source code. Dynamic learning from audit data is used to supplement the base model to provide a model that exactly follows the definition in the executable but that includes legal behavior determined at runtime. Our model is similar to the VPStatic model proposed by Feng, …

Definition, Analysis, And An Approach For Discrete-Event Simulation Model Interoperability, Tai-Chi Wu

Theses and Dissertations

Even though simulation technology provides great benefits to industry, it is largely underutilized. One of the biggest barriers to utilizing simulation is the lack of interoperability between simulation models. This is especially true when simulation models that need to interact with each other span an enterprise or supply chain. These models are likely to be distributed and developed in disparate simulation application software. In order to analyze the dynamic behavior of the systems they represent, the models must interoperate. However, currently this interoperability is nearly impossible. The interaction of models also refers to the understanding of them among stakeholders in …

A Consideration Of Church Planting Through Radio Broadcasting In Thailand, Byung Jo Chang

Doctoral Dissertations and Projects

This dissertation focuses on the meaning of church planting, and the successful church planning through radio broadcasting and its benefit in Thai missions. Radio broadcasting is the best way of opening up the door for spreading the gospel to start church planting. The research focuses on founding and organizing the broadcasting station in the hopes of giving non Christians opportunities to hear the gospel for the first time, and helping them to become Chris like.

The potential radio broadcasting missions carry, the meaning of it all, and the efficiency behind planting a church through the broadcasting missions is examined. These …

Critical Analysis Of Sic Sit Design And Performance Based Upon Material And Device Properties, Yunmo Sung

Theses and Dissertations

Recently, the need for high power, high frequency devices continues to grow with the increase in wireless communication, radar systems, HDTV, digital communication, and other military application of the RF spectrum. Traditionally when higher power is needed, one needs to either combine the output power of multiple devices or use vacuum tubes, which are still uncontested at very high power levels, capable of up to a few hundred kilowatts at 5 GHz [11]. But wide band gap semiconductor devices capable of competing in this application. Moreover, the static induction transistor (SIT) in silicon carbide can provide very high total power …

Cyanate Ester, Epoxy And Epoxy/Cyanate Ester Matrix Polyhedral Oligomeric Silsesquioxane Nanocomposites, Kaiwen Liang

Theses and Dissertations

Cyanate ester (PT-15, Lonza Corp) composites containing the inorganic-organic hybrid polyhedral oligomeric silsesquioxanes (POSS), octaaminophenyl(T8)POSS (C6H4NH2)8(SiO1.5)8, cyanopropylheptacyclopentyl(T8)POSS, (C5H9)7(SiO1.5)8(CH2) 3CN or TriSilanolPhenylPOSS (C42H38O12Si7), were synthesized respectively. These PT-15/POSS composites were characterized by FT-IR, X-ray diffraction (XRD), small-angle neutron scattering (SANS), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (X-EDS), transmission electron microscopy (TEM), dynamic mechanical thermal analysis (DMTA) and three-point bending flexural tests. XRD, TEM and IR data are all consistent with molecular dispersion of octaaminophenyl(T8)POSS and TriSilanolPhenylPOSS due to the chemical bonding of the POSS macromer into the continuous cyanate ester network phase. In contrast to octaaminophenyl(T8) POSS and TriSilanolPhenylPOSS, …

The Geology And Hydrology Of The Proposed Upper Mccurtain Creek Watershed Impoundment Choctaw County, Mississippi, Leonard D (Leonard Dwight) Rawlings

Theses and Dissertations

The McCurtain Creek watershed was proposed for a large reservoir project resulting in the commissioning of this study to assess the site?s geology, hydrogeology, and surface hydrology to find whether or not the site was suitable. Data was collected from 57 geophysical logs from coal exploration boreholes to produce geologic and aquifer cross sections. A program to assess discharge identified surface hydrology characteristics of the stream at five locations. Twenty-seven geotechnical boreholes, 23 standpipe piezometers, and the data from the coal exploration were used to map the water table using ArcGIS 8.3 software. Eighteen piezometers at stream sites, used to …

Empirical Findings On Persuasiveness Of Recommender Systems For Customer Decision Support In Electronic Commerce, Qinyu Liao

Theses and Dissertations

More and more companies are making online presence by opening online stores and providing customers with company and products information but the overwhelming amount of information also creates information overload for the customers. Customers feel frustrated when given too many choices while companies face the problem of turning browsers into actual buyers. Online recommender systems have been adopted to facilitate customer product search and provide personalized recommendation in the market place. The study will compare the persuasiveness of different online recommender systems and the factors influencing customer preferences. Review of the literature does show that online recommender systems provide customers …