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Articles 2071 - 2100 of 2584

Full-Text Articles in Engineering

Women As Sustainability Leaders In Engineering: Evidence From Industry And Academia, Jennilee Harrison May 2010

Women As Sustainability Leaders In Engineering: Evidence From Industry And Academia, Jennilee Harrison

All Theses

Women are underrepresented in engineering education and practice, which limits the quality of the engineering workforce. One way to increase the participation of women in engineering is to emphasize subjects that appeal to them and emphasize skills at which they are especially adept. A subject that may fit this description is sustainability. The purpose of this research is to compare the percentage of women in selected sustainable engineering leadership positions to the percentage of women in general engineering leadership positions, to examine whether the subject of sustainability may help increase participation of women in engineering. Gender data was collected for …

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Re-Engineering A Trash/Recycling Collection Vehicle Based On Challenging Customer Requirements, Edward Smith May 2010

Re-Engineering A Trash/Recycling Collection Vehicle Based On Challenging Customer Requirements, Edward Smith

All Theses

Engineering design starts with the definition of design requirements. These requirements define the design problem and must be satisfied for a solution to be acceptable. While many design methodologies exist for defining design requirements, none presently provides a systematic approach for designers to challenge requirements. Yet, Pahl and Beitz, Hazelrigg, and Suh all argue that a designer should continually question the need for each requirement and refine them as the product evolves. Thus, there exists a need to develop a comprehensive method that enables a designer to verify, review/question, and revise requirements throughout the design process. This research uses the …

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System Modeling And Power Management Strategy For A Series Hydraulic Hybrid Vehicle, Sisay Molla May 2010

System Modeling And Power Management Strategy For A Series Hydraulic Hybrid Vehicle, Sisay Molla

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A hydraulic hybrid vehicle draws propulsion power from an internal combustion engine as its prime mover and a gas-charged hydro-pneumatic accumulator as its energy buffer. The accumulator serves the purposes of storing regenerated braking energy and supplementing engine power as determined by an on-board power management strategy. In the configuration known as a series hydraulic hybrid powertrain, the engine is mechanically decoupled from the vehicle's wheels thereby offering excellent opportunities for maximizing energy efficiency and reducing pollutant emissions.
This thesis dealt with the development of a causally interconnected, non-linear, dynamic model of a series hydraulic hybrid powertrain featuring independently controllable …

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Vehicle Steering Systems - Hardware-In-The-Loop Simulator, Driving Preferences, And Vehicle Intervention, Jesse Black May 2010

Vehicle Steering Systems - Hardware-In-The-Loop Simulator, Driving Preferences, And Vehicle Intervention, Jesse Black

All Dissertations

The steering system is a critical component of all ground vehicles regardless of their propulsion source. Chassis directional control is provided by the steering system, which in turn relays valuable feedback about the road and vehicle behavior. As the primary feedback channel to the driver, the steering system also delivers the initial perception of a vehicle's handling and responsiveness to the consumer. Consequently, the steering system is an important aspect of the vehicle's evaluation and purchasing process, even if drivers are unaware of its direct influence in their decision making. With automobile purchases potentially hinging on the steering system, a …

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Cross-Layer Scheduling Protocols For Mobile Ad Hoc Networks Using Adaptive Direct-Sequence Spread-Spectrum Modulation, Brian Wolf May 2010

Cross-Layer Scheduling Protocols For Mobile Ad Hoc Networks Using Adaptive Direct-Sequence Spread-Spectrum Modulation, Brian Wolf

All Dissertations

We investigate strategies to improve the performance of transmission schedules for mobile ad hoc networks (MANETs) employing adaptive direct-sequence spread-spectrum (DSSS) modulation. Previously, scheduling protocols for MANETs have been designed under the assumption of an idealized, narrowband wireless channel. These protocols perform poorly when the channel model incorporates distance-based path loss and co-channel interference. Wideband communication systems, such as DSSS systems, are more robust in the presence of co-channel interference; however, DSSS also provides multiple-access capability that cannot be properly leveraged with a protocol designed for narrowband systems. We present a new transmission scheduling protocol that incorporates link characteristics, spreading …

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Energy And Nutrient Recovery From Anaerobic Treatment Of Organic Wastes, Christian-Dominik Henrich May 2010

Energy And Nutrient Recovery From Anaerobic Treatment Of Organic Wastes, Christian-Dominik Henrich

All Dissertations

The objective of the research was to develop a complete systems design and predictive model framework of a series of linked processes capable of providing treatment of landfill leachate while simultaneously recovering nutrients and bioenergy from the waste inputs. This proposed process includes an 'Ammonia Recovery Process' (ARP) consisting of: 1) ammonia de-sorption requiring leachate pH adjustment with lime or sodium hydroxide addition followed by, 2) ammonia re-absorption into a 6-molar sulfuric acid spray-tower followed by, 3) biological activated sludge treatment of soluble organic residuals (BOD) followed by, 4) high-rate algal post-treatment and finally, 5) an optional anaerobic digestion process …

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Grain Boundary Premelting And Activated Sintering In Binary Refractory Alloys, Xiaomeng Shi May 2010

Grain Boundary Premelting And Activated Sintering In Binary Refractory Alloys, Xiaomeng Shi

All Dissertations

Quasi-liquid intergranular film (IGF) which has been widely observed in ceramic systems can persist into sub-solidus region whereby an analogy to Grain boundary (GB) premelting can be made.
In this work, a grain boundary (GB) premelting/prewetting model in a metallic system was firstly built based on the Benedictus' model and computational thermodynamics, predicting that GB disordering can start at 60-85% of the bulk solidus temperatures in selected systems. This model quantitatively explains the long-standing mystery of subsolidus activated sintering in W-Pd, W-Ni, W-Co, W-Fe and W-Cu, and it has broad applications for understanding GB-controlled transport kinetics and physical properties. Furthermore, …

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Fpga Based Timing Module And Optical Communication Card Design For Spallation Neutron Source, Biswa Singh May 2010

Fpga Based Timing Module And Optical Communication Card Design For Spallation Neutron Source, Biswa Singh

All Theses

The Timing Module and Optical Communication Card (OCC) are used for acquisition of neutron event data by the instrument systems at the Spallation Neutron Source (SNS) neutron scattering facility. The instrument systems produce a very large flux of neutrons of varying energies over a short time period through the spallation process. The Timing Module and OCC require high-bandwidth communication to ensure high-speed data movement to the memory in the data collection system without loss of neutron data. The existing implementations use a standard PCI-X bus interface to transfer the data between the cards and the host computer. The data processing …

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An Integral Equation Analysis Of A Two-Aperture Coaxial Waveguide, John Luke May 2010

An Integral Equation Analysis Of A Two-Aperture Coaxial Waveguide, John Luke

All Theses

Two different, two-aperture coaxial waveguide configurations are modeled. Integral equations are formulated and then solved by means of the Method of Moments. The results of the analyses are used to formulate a microwave network representation for each structure. Commercial electromagnetic modeling software, along with data acquired through the building and testing of one of the structures, is used to prove the validity of the solution technique developed within the text.

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Kinetic And Finite Element Modeling For Firing Brick, Daniel Mckinney May 2010

Kinetic And Finite Element Modeling For Firing Brick, Daniel Mckinney

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Kinetic modeling and simulation were used to optimize the firing cycle for brick. This was done to develop a tool for the brick industry to reduce fuel consumption and emissions during firing. A kinetic model was built using shrinkage data from dilatometer measurements and mass loss data from thermogravimetry measurements in order to predict the density as a function of temperature and time. The density of brick was related to the absorption coefficient (C/B), an ASTM standard which is related to the durability of the brick. The kinetic model was used to optimize the firing curve using a rate controlled …

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Comprehensive Analysis Of A Student-Centered Active-Learning Integrated Statics And Dynamics Course For Mechanical Engineers, Marisa Orr May 2010

Comprehensive Analysis Of A Student-Centered Active-Learning Integrated Statics And Dynamics Course For Mechanical Engineers, Marisa Orr

All Theses

The Student-Centered Active Learning in Undergraduate Programs (SCALE-UP) approach to instructional design was adapted with the goal of delivering more effective statics, dynamics and multivariate calculus instruction and integrated course curricula. Inquiry-based learning exercises were designed, incorporating material from statics and dynamics into multivariable calculus, and vice-versa, as well as integrating statics and dynamics into one course. Analysis included an exploration of student study habits, multiple measures of course effectiveness, and an examination of curricular effects. Challenges of implementation are also discussed.
Study habits of students in an integrated Statics and Dynamics course were assessed through a voluntary survey in …

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A Proposed Method To Identify Requirements Significant To Mass Reduction, James Mclellan May 2010

A Proposed Method To Identify Requirements Significant To Mass Reduction, James Mclellan

All Theses

Reducing the mass of engineering products holds the potential for significant benefits by reducing material costs, environmental impact, transportation costs, and in the case of vehicles, reducing fuel consumption. While there are many approaches for reducing mass, analyzing requirements has the greatest potential since requirements definition is the earliest phase of product development, where the most design freedom exists. This thesis proposes a requirement analysis method that identifies requirements that impact significant amounts of mass. The research hypothesis is: Engineering requirements can be represented and processed in a systematic manner and linked to physical components and systems, thus enabling mass …

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Maximizing Throughput Using Dynamic Resource Allocation And Discrete Event Simulation, Gregory Gunn May 2010

Maximizing Throughput Using Dynamic Resource Allocation And Discrete Event Simulation, Gregory Gunn

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This research studies a serial two stage production system with two flexible servers which can be dynamically assigned to either station. This is modeled using discrete event simulation and more specifically the Arena software package by Rockwell. The goal is to determine dynamic allocation policies based upon the inventory level at each station to maximize the throughput of finished goods out of the system. This model adds to previous work by including actual switching time. The effect of the pre-emptive resume assumption is gauged, and the effectiveness of the OptQuest optimization package is also tested. Studies are conducted to determine …

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A Comparison Of Small Scale Laboratory Experiments With The Environmetnal Protection Agency Reccomended Dense Gas Dispersion Models: An Assessment Of The Validity Of Salt Bath Modeling Of Atmospheric Flows, Katie Betz May 2010

A Comparison Of Small Scale Laboratory Experiments With The Environmetnal Protection Agency Reccomended Dense Gas Dispersion Models: An Assessment Of The Validity Of Salt Bath Modeling Of Atmospheric Flows, Katie Betz

All Theses

Accurate dense gas dispersion modeling is important in a number of fields from modeling smoke movement in a room to the spreading of dense toxic gas releases such as resulted from the Chlorine spill in Graniteville, SC in 2005. To this end, a series of small scale laboratory experiments using instantaneous releases of a cylindrical, finite volume of dense salt water were performed. In the experiments, the horizontal spread of the dense liquid over a flat surface(i.e. gravity current front position over time) was measured.
The results of these small scale experiments were compared to two dense gas dispersion models …

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Detecting And Tracking Tractor-Trailers Using View-Based Templates, Vinay Gidla May 2010

Detecting And Tracking Tractor-Trailers Using View-Based Templates, Vinay Gidla

All Theses

Vehicle tracking and classification is an important application of computer vision. There exist mainly two types of tracking techniques: Appearance-based tracking and Feature-based tracking.
Appearance-based techniques generally require a model or template of the target to be tracked. However the model needs to be robust to the multitude of deformations possible in the course of the target's movement. This research explores the use of a collection of view based templates, instead of a single template, to accurately trace the contours of the tractor-trailers in moving traffic.

The tracking begins with creation of a template sequence by manually processing a segment …

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Long-Term Performance Of Pavement Markings On Primary And Secondary Roads, Joshua Johnson May 2010

Long-Term Performance Of Pavement Markings On Primary And Secondary Roads, Joshua Johnson

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This research analyzes waterbased and thermoplastic pavement markings on primary and secondary roads in South Carolina. The primary objective of this research was to develop retroreflectivity degradation models for these two pavement marking materials, as well as determine the expected useful life of the markings. Predicting retroreflectivity and marking life is important so that state DOTs may efficiently replace markings in order to reduce safety hazards as well as maintenance costs.
Data collection for this research lasted 21 months, where retroreflectivity of pavement markings was measured on over 100 primary and secondary roads in South Carolina. Variables such as marking …

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Liquefaction Analysis Of Three Pleistocene Sand Deposits That Did Not Liquefy During The 1886 Charleston, South Carolina Earthquake Based On Shear Wave Velocity And Penetration Resistance, Aaron Geiger May 2010

Liquefaction Analysis Of Three Pleistocene Sand Deposits That Did Not Liquefy During The 1886 Charleston, South Carolina Earthquake Based On Shear Wave Velocity And Penetration Resistance, Aaron Geiger

All Theses

The results of geotechnical investigations at three sites located in the South Carolina Coastal Plain are presented in this thesis. The three sites are called the Hobcaw Barony Borrow Pit site located near Georgetown, SC; the Rest Area Ponds site near Walterboro, SC; and the Lowcountry Sand & Gravel site, also near Walterboro. Near-surface sand deposits at these sites ranged in geologic age from 200,000 to greater than 1,000,000 years. These three sites lie well outside the region of most liquefaction effects observed following the 1886 Charleston earthquake. Investigations conducted at the sites include seismic cone penetration tests with pore …

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Modeling Phosphate Adsorption For South Carolina Soils, Jesse Cannon May 2010

Modeling Phosphate Adsorption For South Carolina Soils, Jesse Cannon

All Theses

Eroded sediment and the pollutants it transports are problems in water bodies in South Carolina (SC) and the United States as a whole. Current regulations and engineering practice attempt to remedy this problem by trapping sediment according to settling velocity, and thus, particle size. However, relatively little is known about most eroded soils. In most cases, little experimental data are available to describe a soil's ability to adsorb a pollutant of interest. More-effective design tools are necessary if design engineers and regulators are to be successful in reducing the amount of sediment and sediment-bound pollutants in water bodies. This study …

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Traffic Analysis Of Anonymity Systems, Ryan Craven May 2010

Traffic Analysis Of Anonymity Systems, Ryan Craven

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This research applies statistical methods in pattern recognition to test the privacy capabilities of a very popular anonymity tool used on the Internet known as Tor.
Using a recently developed algorithm known as Causal State Splitting and Reconstruction (CSSR), we can create hidden Markov models of network processes proxied through Tor. In contrast to other techniques, our CSSR extensions create a minimum entropy model without any prior knowledge of the underlying state structure. The inter-packet time delays of the network process, preserved by Tor, can be symbolized into ranges and used to construct the models.
After the construction of training …

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Performance Of Expanded Polymer Cushion Materials At Less Than One Inch In Thickness, Glen Potter May 2010

Performance Of Expanded Polymer Cushion Materials At Less Than One Inch In Thickness, Glen Potter

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The purpose of this work is to determine whether peak acceleration values can be predicted from existing cushion curves for polymeric materials with thicknesses less than one inch. The secondary purpose is to determine whether the stress energy method of cushion testing can be applied to polymeric foams with thicknesses less than one inch. Cushion curves were created from materials greater than one inch in thickness and from materials less than one inch in thickness. The curves were compared using three methods; linear regression, comparison of cushion curves by ASTM allowable difference between curves and comparison of predicted acceleration values …

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An Assessment Of Linear Wrist Motion During The Taking Of A Bite Of Food, Meredith Drennan May 2010

An Assessment Of Linear Wrist Motion During The Taking Of A Bite Of Food, Meredith Drennan

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Motivated by the goal of building a device capable of detecting when a user takes a bite of food, we examine whether there is a correlation between linear wrist motion and bite detection. Such a device could be used to manage weight loss by tracking eating trends over time and providing real time feedback to the user regarding eating rate or total consumption. A comprehensive analysis of tracking linear motion using low cost inertial sensors is presented. Based on this theory, we discuss the design and tracking accuracy of a prototype bite counting device. We show that tracking position using …

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Comparision Of Open Graded Friction Course Mix Design Methods Currently Used In The United States, Laura Kline May 2010

Comparision Of Open Graded Friction Course Mix Design Methods Currently Used In The United States, Laura Kline

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This research compares the open graded friction course (OGFC) mix design methods which are currently being used in the United States. OGFCs are a type of porous pavement that have been used in the United States since 1944, but has provided inconsistent and highly variable performance results. The design procedures for several agencies were obtained, and then compared for similarities. All of the design methods were then conducted to determine the optimum binder content. The optimum binder content (OBC) of a single aggregate gradation for each method was tested for properties and performance characteristics.
The design methods which are currently …

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Characterization And Modification Of Helmet Padding System To Improve Shockwave Dissipation, Katelyn Howay May 2010

Characterization And Modification Of Helmet Padding System To Improve Shockwave Dissipation, Katelyn Howay

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Currently soldiers are being exposed a much higher number of improvised explosive devices (IEDs) and the resulting shockwaves. These shockwaves can cause traumatic brain injuries (TBIs) even without the occurrence of ballistic impact. The focus of this research was to reduce the amount of shockwaves soldiers are exposed to by inserting fibers and woven fabrics into a foam padding system. These fibers and fabrics facilitate the dissipation of the shockwave energy before it is able to penetrate the padding and cause TBIs.
The sound velocity of high-performance fibers, commodity fibers and woven fabric was measured using a Dynamic Modulus Tester. …

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Performance Evaluation Of Sbs Modified Asphalt Mixtures Using Warm Mix Technologies, Hakseo Kim May 2010

Performance Evaluation Of Sbs Modified Asphalt Mixtures Using Warm Mix Technologies, Hakseo Kim

All Theses

The need for more sustainable methods and techniques in industry has been increasing and it is important to respond to the needs of society and address issues surrounding its environment and health. In order to better introduce such new and more sustainable methods, it is necessary to combine existing and proven methods with new technology. The main idea of this research was to use the established industry standard of using Styrene Butadiene Styrene (SBS) modified binder and combine it with the relatively new Warm Mix Asphalt (WMA) technology in order to create a more sustainable and eco-friendly asphalt paving process. …

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Acceleration Of Biomolecular Simulations Using Fpga-Based Reconfigurable Computing, Ananth Nallamuthu May 2010

Acceleration Of Biomolecular Simulations Using Fpga-Based Reconfigurable Computing, Ananth Nallamuthu

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A paradigm shift is occurring in the way compute-intensive scientific applications are developed. Thanks to advancements in commercially viable hybrid architectures for High-Performance Computing (HPC), the focus has shifted from improving performance by merely scaling algorithms on von Neumann computing nodes to fully exploiting additional computational capabilities provided by accelerators such as FPGAs (Field Programmable Gate Arrays) and GPGPUs (General Purpose Graphical Processing Units).
Computational chemists use Molecular Dynamics (MD) simulations like LAMMPS (Large Scale Atomic Molecular Massively Parallel Systems) and NAMD (NAnoscale Molecular Dynamics) to simulate biomolecular behaviour such as protein folding and small molecule docking to proteins. MD …

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Interpretability Analysis Of Function Structures At Various Levels Of Abstraction: A User Study, Jonathan Thomas May 2010

Interpretability Analysis Of Function Structures At Various Levels Of Abstraction: A User Study, Jonathan Thomas

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Function models are used during the conceptual design phase of the design process to model the intended use or objective of a product, independent of the products physical form. Function models also aid in guiding design activities such as generating concepts and allocating design team resources. Recent research efforts have focused on the formalization of functional models through a controlled vocabulary and archival of functional representations in computer-based repositories. However, the usefulness and interpretability of these function models has not been rigorously evaluated.
This thesis presents the results of two controlled user studies to ascertain the interpretability of functional representations …

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Software Algorithms To Coordinate And Improve Voltage Sag Ridethrough Capabilities Of Networked Industrial Processes, Owen Parks May 2010

Software Algorithms To Coordinate And Improve Voltage Sag Ridethrough Capabilities Of Networked Industrial Processes, Owen Parks

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For those who design, operate, and troubleshoot industrial processes, electric power quality is a subject that requires much consideration. Processes that use electronic sensors, actuators, and computation devices are heavily reliant on a stable, consistent input power source. When a power quality event such as a voltage fluctuation occurs, automation equipment often behaves unpredictably and causes process malfunction or failure.
Because industrial power consumers often blame their electric utility for these events, some utilities offer process susceptibility studies as a service for their customers. During a typical study, utility technicians and engineers perform in-house tests on suspect components or systems …

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Biodegradation And Bioremediation Of Hexachlorocyclohexane Isomers, Chlorinated Ethenes, Chlorinated Benzenes And Benzene, Vijaikrishnah Elango May 2010

Biodegradation And Bioremediation Of Hexachlorocyclohexane Isomers, Chlorinated Ethenes, Chlorinated Benzenes And Benzene, Vijaikrishnah Elango

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ABSTRACT
Groundwater at an industrial site is contaminated with γ -hexachlorocyclohexane (HCH) and α-HCH (i.e., lindane) (0.3-0.5 ppm). Other contaminants in the 1-15 ppm range include 1,2,4-trichlorobenezene (TCB), 1,2-dichlorobenzene (DCB), 1,3-DCB, 1,4-DCB, chlorobenzene (CB), benzene, trichloroethene (TCE) and cis-1,2-dichloroethene (cDCE). The aquifer consists of a shallow layer of soil over fractured dolomite, where most of the contaminant mass resides. The objective of this study was to compare 1) anaerobic reductive dechlorination of the polychlorinated contaminants, followed by aerobic biodegradation of the daughter products (mainly DCBs, CB, and benzene); and 2) aerobic biodegradation of α- and γ-HCH, TCB, DCBs, CB and …

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Fabrication Of Transparent Ceramic Laser Media For High Energy Laser Applications, Karn Serivalsatit May 2010

Fabrication Of Transparent Ceramic Laser Media For High Energy Laser Applications, Karn Serivalsatit

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Sesquioxides of yttrium, scandium, and lutetium, i.e., Y2O3, Sc2O3, and Lu2O3, have received a great deal of recent attention as potential high power solid state laser hosts. These oxides are receptive to lanthanide doping, including trivalent Er, Ho and Tm which have well known emissions at eye-safe wavelengths that can be excited using commercial diode lasers. These sesquioxides are considered superior to the more conventional yttrium aluminum garnet (YAG) due to their higher thermal conductivity, which is critical for high power laser system. Unfortunately, these oxides possess high …

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A Lyapunov Based Approach To Energy Maximization In Renewable Energy Technologies, Erhun Iyasere May 2010

A Lyapunov Based Approach To Energy Maximization In Renewable Energy Technologies, Erhun Iyasere

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This dissertation describes the design and implementation of Lyapunov-based control strategies for the maximization of the power captured by renewable energy harnessing technologies such as (i) a variable speed, variable pitch wind turbine, (ii) a variable speed wind turbine coupled to a doubly fed induction generator, and (iii) a solar power generating system charging a constant voltage battery.
First, a torque control strategy is presented to maximize wind energy captured in variable speed, variable pitch wind turbines at low to medium wind speeds. The proposed strategy applies control torque to the wind turbine pitch and rotor subsystems to simultaneously control …

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