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Theses/Dissertations

2007

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Articles 1 - 30 of 1410

Full-Text Articles in Engineering

Optimization Of Optical Computed Tomography Techniques For The Synthesis Of Particle Aggregate Models, Patrick Anthony Giordano Jr. Dec 2007

Optimization Of Optical Computed Tomography Techniques For The Synthesis Of Particle Aggregate Models, Patrick Anthony Giordano Jr.

Theses and Dissertations

The characterization of 3-D shapes of particles in geomaterial aggregate mixtures is important for understanding the micro-mechanics of granular materials. Also, numerical synthesis of 3-D particle shapes from their corresponding shape descriptors is required for developing discrete element models (DEMs) that can be used to predict particle contact-forces, and ultimately the shear strength of the aggregate mixture.

Previous work has shown that Fourier-based 3-D shape descriptors can be constructed for aggregate mixtures, using a statistical combination of 2-D projections. Furthermore, optical tomography methods using the Algebraic Reconstruction Technique (ART) algorithm has proved capable of synthesizing 3-D shapes from 2-D projections ...


Interactive Visualization Of Information Hierarchies And Applications On The Web, Confesor Santiago Iii Dec 2007

Interactive Visualization Of Information Hierarchies And Applications On The Web, Confesor Santiago Iii

Theses and Dissertations

The visualization of information hierarchies is concerned with the presentation of abstract hierarchical information about relationships between various entities. It has many applications in diverse domains such as software engineering, information systems, biology, and chemistry. Information hierarchies are typically modeled by an abstract tree, where vertices are entities and edges represent relationships between entities. The aim of visualizing tree drawings is to automatically produce drawings of trees which clearly reflect the relationships of the information hierarchy.

This thesis is primarily concerned with problems related to the automatic generation of area-efficient grid drawings of trees, interactively visualizing information hierarchies, and applying ...


Odometry Correction Of A Mobile Robot Using A Range-Finding Laser, Thomas Epton Dec 2007

Odometry Correction Of A Mobile Robot Using A Range-Finding Laser, Thomas Epton

All Theses

Two methods for improving odometry using a pan-tilt range-finding laser is considered. The first method is a one-dimensional model that uses the laser with a sliding platform. The laser is used to determine how far the platform has moved along a rail. The second method is a two-dimensional model that mounts the laser to a mobile robot. In this model, the laser is used to improve the odometry of the robot. Our results show that the one-dimensional model proves our basic geometry is correct, while the two-dimensional model improves the odometry, but does not completely correct it.


Incorporating Grain Size Effects In Taylor Crystal Plasticity, Bradley S. Fromm Dec 2007

Incorporating Grain Size Effects In Taylor Crystal Plasticity, Bradley S. Fromm

Theses and Dissertations

A method to incorporate grain size effects into crystal plasticity is presented. The classical Hall-Petch equation inaccurately predicts the macroscopic yield strength for materials with non-equiaxed grains or materials that contain unequal grain size distributions. These deficiencies can be overcome by incorporating both grain size and orientation characteristics into crystal plasticity theory. Homogenization relationships based on a viscoplastic Taylor-like approach are introduced along with a new function, the grain size and orientation distribution function (GSODF). Estimates of the GSODF for high purity α-titanium are recovered through orientation imaging microscopy coupled with the chord length distribution. A comparison between the new ...


Forensics Image Background Matching Using Scale Invariant Feature (Sift)Transform And Speeded Up Robust Features (Surf), Paul N. Fogg Ii Dec 2007

Forensics Image Background Matching Using Scale Invariant Feature (Sift)Transform And Speeded Up Robust Features (Surf), Paul N. Fogg Ii

Theses and Dissertations

In criminal investigations, it is not uncommon for investigators to obtain a photograph or image that shows a crime being committed. Additionally, thousands of pictures may exist of a location, taken from the same or varying viewpoints. Some of these images may even include a criminal suspect or witness. One mechanism to identify criminals and witnesses is to group the images found on computers, cell phones, cameras, and other electronic devices into sets representing the same location. One or more images in the group may then prove the suspect was at the crime scene before, during, and/or after a ...


Acceleration Of The Maturation Of Tissue Engineered Grafts By Dynamic Force Stimulation Or Gene Therapy, Shila Taylor Dec 2007

Acceleration Of The Maturation Of Tissue Engineered Grafts By Dynamic Force Stimulation Or Gene Therapy, Shila Taylor

All Theses

Over 16 million people suffer from osteoarthritis (OA). As the body ages OA and other cartilage diseases create an imbalance of anabolic and catabolic cell activities in cartilage and or over time the cartilage is damaged and wears away which creates lesion that resulting in pain. Most clinical surgeries are either temporary or have not gone through trials to test their success. For a long term solution researchers have been looking at replacing cartilage with a tissue engineered graft. One of the major problems to date has been is the strength of the scaffold.
Natural cartilage needs loading for its ...


Electrical Activation Studies Of Silicon Implanted Aluminum Gallium Nitride With High Aluminum Mole Fraction, Elizabeth A. Moore Dec 2007

Electrical Activation Studies Of Silicon Implanted Aluminum Gallium Nitride With High Aluminum Mole Fraction, Elizabeth A. Moore

Theses and Dissertations

This research demonstrates a method for producing highly conductive Si-implanted n-type aluminum gallium nitride (AlxGa1-xN) alloys, and represents a comprehensive analysis of the resulting material's electrical and optical properties as a function of Al mole fraction, anneal temperature, anneal time, and implantation dose. Highly conductive alloys are critical to the fabrication of devices operating in deep UV, high-temperature, high-power, and high-frequency environments, and thus this research is significant in regard to the application of such devices. The AlxGa1-xN wafers of this study, with Al concentrations of 10 to 50%, were implanted ...


Metalloporphyrin Catalyzed Degradation Of Pce: Effects Of Reductants, Buffers And Cosolvent Concentration, Sowmya Suryanarayanan Dec 2007

Metalloporphyrin Catalyzed Degradation Of Pce: Effects Of Reductants, Buffers And Cosolvent Concentration, Sowmya Suryanarayanan

All Theses

Reductive dechlorination of chlorinated organic contaminants using metalloporphyrins as catalysts may be an effective approach to treat widespread contamination. However, most previous studies have examined water-soluble rather than insoluble metalloporphyrins despite the fact that the latter category makes up the largest fraction found in nature. Recent studies have shown that addition of different cosolvents to water can activate otherwise non-reactive metalloporphyrin catalysts and facilitate the reduction of tetrachloroethylene (PCE), presumably by the mere process of making the otherwise insoluble metalloporphyrins dissolve in solution. Therefore, solubility has been advanced as a key factor in the ability of metalloporphyrins to catalyze organic ...


Bacterial Auto-Aggregation And Co-Aggregation In Activated Sludge, Fei Chen Dec 2007

Bacterial Auto-Aggregation And Co-Aggregation In Activated Sludge, Fei Chen

All Theses

Microbial auto-aggregation and co-aggregation, leading to biofilm or floc formation, widely occur in natural systems. This study was conducted to investigate the extent of bacterial auto-aggregation and co-aggregation in activated sludge and their contributions in activated sludge floc formation. In this study, an activated sludge sample was separated into a supernatant part (planktonic community) and a sediment part (floc community) by centrifugation at 650_g for 2 minutes. 197 strains were isolated from both communities. These isolates belong to 18 phylotypes based on molecular identifications. Similar phylogenetic distributions of these isolates were observed in planktonic and floc communities, suggesting a similar ...


Property Measurements And Evaluation Of Heat Leak, Nathan Race Dec 2007

Property Measurements And Evaluation Of Heat Leak, Nathan Race

All Theses

Heat transport in capillary wick structures is an important parameter in loop heat pipe (LHP) design. The purpose of this study was to investigate the conductive heat leak in operating capillary wick structures. The heat leak is the portion of applied heat load conducted through the wick in spite of the convection of working fluid. Four sintered 316 stainless steel wicks were tested for porosity, effective thermal conductivity, pore size, and heat leak. Pore sizes were found to correlate well with the nominal pore size and pores were very narrowly distributed within a size range of approximately 1-10μm. Effective thermal ...


Development Of The Impedance-Based Arc-Flash Determination Device (Iadd), Timothy Smith Dec 2007

Development Of The Impedance-Based Arc-Flash Determination Device (Iadd), Timothy Smith

All Theses

This thesis entitled, 'Development of the Impedance based Arc-Fault Determination Device (IADD)' details the development of a testing device that, when attached to an electrical node on the power system and through observations on voltage, current and phase shift with a step load change, determines the effective Thevenin or Norton impedance at the point of test. This thesis includes discussion of the theory and design process that enables the determination of an equivalent circuit, software development using National Instruments' LabView software development package and suggestions for future development.
The purpose of this thesis is to produce a device that can ...


Bio-Surfaces And Geometric References For A Standardized Biomechanical Design Methodology For Mass Customization, Kimberly A. Jensen Dec 2007

Bio-Surfaces And Geometric References For A Standardized Biomechanical Design Methodology For Mass Customization, Kimberly A. Jensen

Theses and Dissertations

This dissertation presents a method for the design of customizable products that interface with the human body. The method presented involves first, a consistent method of capturing and representing the human model so that the model can be used with CAx tools and solid modeling techniques. Second, it provides a design methodology based on feature structure planning and assembly modeling that provides a consistent structure to the design process so that it can be reused and parameterized. Third, a strategy for identifying parametric variables that are referenced to the human body is introduced. The core of this method is the ...


Evaluation Of A Computer Vision Traffic Surveillance System, Robert Graham Dec 2007

Evaluation Of A Computer Vision Traffic Surveillance System, Robert Graham

All Theses

This thesis presents an evaluation of the accuracy of a novel computer vision traffic sensor - developed by the Clemson University Electrical and Civil Engineering Departments - capable of collecting a variety of traffic parameters. More specific, the thesis examines how the camera height and distance from the travel way affects the accuracy. The details of the quantitative and qualitative evaluations used to validate the system are provided. The parameters chosen to evaluate were volume, vehicle classification, and speed. Experimental results of cameras mounted at heights of 20 and 30 feet and a lateral distance of 10 and 20 feet show accuracy ...


Thermal Diffusion Coefficient Modeling For High Pressure Combustion Simulations, Soundararaghavan Vasudevan Dec 2007

Thermal Diffusion Coefficient Modeling For High Pressure Combustion Simulations, Soundararaghavan Vasudevan

All Theses

The effects of Soret and Dufour diffusion on the behavior of high pressure laminar diffusion flames relevant to modern combustion devices are investigated. A novel model for thermal diffusion coefficients is developed based on experimental data found in the literature and the principle of corresponding states. The new model is first compared with existing models and experimental data and is shown to be more accurate and to exhibit correct behavior in the limit of high temperature relevant to combustion. The model furthermore does not exhibit sensitivity to the equation of state, its mixing rules, or unphysical sign changes observed in ...


The Role Of Computer Aided Engineering In Developing A Combined Trash And Recycling Truck : A Case Study, Peter Johnston Dec 2007

The Role Of Computer Aided Engineering In Developing A Combined Trash And Recycling Truck : A Case Study, Peter Johnston

All Theses

This work will illustrate how Environmental America Inc., EAI, and the Clemson University design team utilized lean manufacturing principles to revolutionize the curbside waste collection process. Through the application of lean manufacturing principles the number of non-value added steps was significantly reduced and the information gathered from the lean process tree acted as a framework to develop initial constraints and criteria for the vehicle's development. The design team was asked to construct the fifth iteration of the prototype collection vehicle in an effort to minimize vehicle cost, size and weight. An extensive case study will be presented which illustrates ...


Fabrication, Electrical Characterization, And Annealing Of Al/, Cu/, And Au/4h-Sic Schottky Diodes, Nikhil Karkhanis Dec 2007

Fabrication, Electrical Characterization, And Annealing Of Al/, Cu/, And Au/4h-Sic Schottky Diodes, Nikhil Karkhanis

All Theses

Schottky diodes were fabricated on n-type 4H-SiC with Nickel ohmic contacts and Aluminum, Copper, and Gold Schottky contacts. An improved and revised fabrication process was developed in the course of this research project. The Schottky diodes were electrically characterized using I-V and C-V measurements to extract electrical parameters which include Schottky barrier height, ideality factor, the diode series resistance, and substrate doping density. Al/4H-SiC and Au/4H-SiC were annealed at 600¼C and 500¼C respectively to improve the Schottky parameters. Schottky barrier height was raised and the ideality factor was reduced in both cases. Significant improvement was observed in the ...


Laboratory Evaluation Of Microbial Aggregation In Activated Sludge, Xiaoling Liu Dec 2007

Laboratory Evaluation Of Microbial Aggregation In Activated Sludge, Xiaoling Liu

All Theses

Microbial aggregation was investigated in this study using the activated sludge process as a model system, the performance of which is highly dependent on effective bioaggregation. This research includes two experiments. First, four laboratory-scale activated sludge sequencing batch reactors (SBRs) were constructed in order to evaluate the effect of solids retention time (SRT) on microbial aggregation. These SBRs were operated at SRT of 4, 8, 16, and 32 days, respectively, fed with a protein-based synthetic wastewater, and monitored over a period of 268 days for performance and sludge settling characteristics including soluble COD in the effluent (sCOD), sludge volume index ...


Operational Strategies For Continuum Manipulators, Matt Csencsits Dec 2007

Operational Strategies For Continuum Manipulators, Matt Csencsits

All Theses

We introduce a novel, intuitive user interface for continuum manipulators through the use of various joystick mappings. This user interface allows for the effective use of continuum manipulators in the lab and in the field. A novel geometric approach is developed to produce a more intuitive understanding of continuum manipulator kinematics. Using this geometric approach we derive the first closed-form solution to the inverse kinematics problem for continuum robots. Using the derived inverse kinematics to convert from workspace coordinates to configuration space coordinates we develop a potential-field path planner for continuum manipulators.


Reducing Curvature In Complex Tool Paths By Deviating From Cam-Produced Tool Paths Within A Tolerance Band, George Benjamin Naseath Dec 2007

Reducing Curvature In Complex Tool Paths By Deviating From Cam-Produced Tool Paths Within A Tolerance Band, George Benjamin Naseath

Theses and Dissertations

This thesis develops an algorithm to decrease high-curvature sections in tool paths for complex parts to achieve shorter machining times resulting in higher production rates. In the research sample cases, the algorithm decreased machining times by 1% to 9% for design-induced sections of high curvature and by 16% to 75% for CAM induced ripples using high path tolerances. High-curvature sections in tool paths are caused by complex part geometry, noise, and discontinuities in the model. The curvature is decreased by deviating the tool path within an allowable path tolerance. The feedrate along the tool path is directly related to the ...


Optical Force Based Cancer Cell Identification, Justin Roman Dec 2007

Optical Force Based Cancer Cell Identification, Justin Roman

All Theses

We present the basis of a novel, non-invasive technique for cell diagnostics which utilizes the optical force generated by a weakly focused laser beam to distinguish cells based on their size, structure, composition, and membrane properties. Cell populations of different types, biological states or with different treatments can be studied. This research focuses on two particular instances where other methods of cell sorting, such as those that require fluorescent markers, are not ideal. What's more, this research emphasizes the ability to sort morphologically similar cells that are identical to the naked eye, but phenotypically different on the molecular level ...


Cosolvent Effects On The Reductive Dechlorination Of Tetrachloroethylene Catalyzed By Iron Tetraphenyl Porphyrin Chloride, Lavanya Ramasubramanian Dec 2007

Cosolvent Effects On The Reductive Dechlorination Of Tetrachloroethylene Catalyzed By Iron Tetraphenyl Porphyrin Chloride, Lavanya Ramasubramanian

All Theses

Abiotic electron transfer mediated reductive dechlorination reactions have been studied extensively in the past decade. Porphyrins and metalloporphyrins are common electron transfer mediators used. Past studies have shown that some metalloporphyrins play a key role in increasing the rate of reaction in the presence of cosolvents. There have also been suggestions that organic cosolvents enhance the rate of reduction by increasing the solubility of metalloporphyrins.
The primary objective of this project was to examine the effect of cosolvents on the metalloporphyrin-catalyzed reductive dechlorination of tetrachloroethylene (PCE). Subsequently, experiments were also conducted to test the hypothesis that metalloporphyrin solubility is linked ...


A Case Study On The Use Of Design Exemplar As A Search And Retrieval Tool, Narasimha Murty Srirangam Dec 2007

A Case Study On The Use Of Design Exemplar As A Search And Retrieval Tool, Narasimha Murty Srirangam

All Theses

This thesis presents a case study examining the suitability of design exemplar technology as a CAD query tool for an industrial scenario. The search and retrieval of geometrically similar mold inserts to save tooling cost for a tire manufacturing company is taken as the case study. During the implementation of the design exemplar as a CAD search and retrieval tool, several limitations of it are identified, such as the difficulty and tediousness in authoring exemplars for real world problems. To overcome these limitations, a new mathematical-based exemplar approach (mathematical model) is developed for tire mold insert retrieval. This approach calculates ...


Least Squares Fitting Of Analytic Primitives On A Gpu, Meghashyam Panyam Mohan Ram Dec 2007

Least Squares Fitting Of Analytic Primitives On A Gpu, Meghashyam Panyam Mohan Ram

All Theses

Metrology systems take coordinate information directly from the surface of a manufactured part and generate millions of (X, Y, Z) data points. The inspection process often involves fitting analytic primitives such as sphere, cone, torus, cylinder and plane to these points which represent an object with the corresponding shape. Typically, a least squares fit of the parameters of the shape to the point set is performed. The least squares fit attempts to minimize the sum of the squares of the distances between the points and the primitive. The objective function however, cannot be solved in the closed form and numerical ...


Effects Of Support Grid Vane Angles On Single Phase Heat Transfer Within Rod Bundle Subchannels, Michael Cosby Dec 2007

Effects Of Support Grid Vane Angles On Single Phase Heat Transfer Within Rod Bundle Subchannels, Michael Cosby

All Theses

The main goal of this project is to investigate how changes in support grid mixing vane angles affect the single phase heat transfer coefficient for rod bundle flows. Since other studies have been done on these types of flows, the present study also serves the purpose of further solidifying conclusions made in those works. A split-pair mixing vane support grid without weld nugget cutouts is thought to have optimum flow characteristics at a vane angle of 29 degrees. Results obtained from this work have shown this to be true. Vane angles were modified to angles of 37 ¡, 33¡ and 21 ...


Surface Finish Control Of 3d Printed Metal Tooling, Brady Godbey Dec 2007

Surface Finish Control Of 3d Printed Metal Tooling, Brady Godbey

All Theses

Solid freeform fabrication (SFF) technology has shown a great deal of promise for the plastic injection molding industry due to its ability to produce complex geometry tooling relatively quickly. However, one shortcoming of metal-based SFF processes is that they have difficulty producing parts with acceptable surface quality. As such, secondary operations, such as machining, are frequently required thereby increasing fabrication time and cost. In addition, there is variation in the surface quality that is dependent upon the surface orientation during the build process. For example, parts produced using the metal-based 3-D printing process have vertical faces with a typical roughness ...


Effect Of Nitrogen Filling On Tire Rolling Resistance And Vehicle Fuel Economy, Prakash Venkataraman Dec 2007

Effect Of Nitrogen Filling On Tire Rolling Resistance And Vehicle Fuel Economy, Prakash Venkataraman

All Theses

There are various losses associated with passenger vehicle that affect its fuel economy as it is being operated. These losses include engine, driveline, aerodynamic and rolling losses. While engine, driveline and aerodynamic losses are inherent with the vehicle due to large number of parts that go into assembling, rolling loss is associated with the vehicle tires and it is the only part of the vehicle that comes in contact with the road. The rolling resistance of inflated tires is an important component of resistance to vehicle motion and contributes to vehicle fuel consumption. Many research works have been focused on ...


Wafer Probe And Package Test Failure Analysis, Deepa Kalva Dec 2007

Wafer Probe And Package Test Failure Analysis, Deepa Kalva

All Theses

In recent years, NAND flash memory has gained a lot of momentum in the semiconductor industry and has become an ideal choice for many consumer and communication products. One of the key elements in the successful production of NAND flash memory is to incorporate elaborate testing methods to ensure functionality and reliability before the part reaches the customer. This in turn necessitates the evaluation and understanding of different failure mechanisms, and the development of methodologies to correct problems.
In this thesis, failure analysis was performed on NAND flash memory at wafer and package level. This involved massive data collection and ...


Development Of A Design Enabler Tool For Frame Analysis For A Small Enterprise: A Case Study, Madhusudan Kayyar Dec 2007

Development Of A Design Enabler Tool For Frame Analysis For A Small Enterprise: A Case Study, Madhusudan Kayyar

All Theses

This case study investigates the design process followed by a small to medium scale enterprise (SME) that primarily depends on special expertise in the form of a few key individuals. These individuals design products mainly based on past experience, augmented by trial and error. This is an inefficient, time consuming, and expensive way of designing products and evaluating their performance. This study critiques the different steps in the current design process, identifying areas of potential improvement and enhancement through application of formal design methods and innovative design enablers. The 'Design Enablers' are design tools that assist the designer at various ...


Distance Estimation Between Transceivers Over Short Distances, Karsten Lowe Dec 2007

Distance Estimation Between Transceivers Over Short Distances, Karsten Lowe

All Theses

Three methods for determining distances between a user and a fixed coordinate system are considered. One system is based on 802.11g packet communications, another on HF radio carrier frequency interference, and the final system on a signal transmitted over a radio channel. Emphasis is placed on the use of these systems in indoor, building-sized environments. Tests are performed to examine the effectivness and potential of these methods. None of the suggested methods are determined to be usable. Reasons for their failure are examined.


An Investigation Of Cavity Pressure As A Process And Quality Indicator In The Micro-Injection Molding Process, Soon-Chun Kuek Dec 2007

An Investigation Of Cavity Pressure As A Process And Quality Indicator In The Micro-Injection Molding Process, Soon-Chun Kuek

All Theses

Increased demand for micro-scale parts and devices is being met in many cases by micro-injection molding of polymer parts. However, part inspection is difficult due to the micro-scale dimension in the micro-injection molding process. In addition, process control also becomes challenging since the process is susceptible to slight changes in process parameters such as mold temperature, injection velocity, and packing pressure. To address these issues, a suitable process monitoring method such as cavity pressure monitoring can be employed to detect any process deviation that may cause defects in part quality. Cavity pressure has been found to be a reliable process ...