Engineering Commons^™

Relative Intensity Noise Study In The Injection-Locked Integrated Electroabsorption Modulator-Lasers, Xiaomin Jin, Bennet Yun Tarng, Shun Lien Chuang

Electrical Engineering

No abstract provided.

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

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. The …

A High Power, High Efficiency Amplifier Using Gan Hemt, Bumjin Kim, Dennis Derickson, Cheng Sun

Electrical Engineering

A class B and a class F power amplifier are described using a GaN HEMT device. They both were designed to operate at a frequency of 1.7 GHz with the same bias conditions. The performances of each amplifier were successfully simulated and compared. A class B amplifier was physically implemented and achieved a high power-added-efficiency of 69.2%, 39.9 dBm output power and associated gain of 14.9 dB. The experimental results were in close agreement to the simulation results.

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 …

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.

A Case Study Investigating Rule Based Design In An Industrial Setting, Siva Chavali

All Theses

This thesis presents a case study on the implementation of a rule based design (RBD) process for an engineer-to-order (ETO) company. The time taken for programming and challenges associated with this process are documented in order to understand the benefits and limitations of RBD. These times are obtained while developing RBD programs for grid assemblies of bottle packaging machines that are designed and manufactured by Hartness International (HI). In this project, commercially available computer-aided design (CAD) and RBD software are integrated to capture the design and manufacturing knowledge used to automate the grid design process of HI. The stages involved …

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 …

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

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 …

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 …

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 …

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 …

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 …

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 …

Assessing Asr Potential Of Hardened Concrete And The Use Of Rice Husk Ash To Mitigate Asr, David Wingard

All Theses

This two part research study was created to first develop a new process using existing test methods to determine the Alkali-Silica Reaction (ASR) potential of hardened concrete that is exposed to external alkalis and secondly to determine the ASR mitigation potential of using rice husk ash (RHA) as a supplementary cementitious material (SCM). The first part of the research study was completed by using a new aggregate extraction procedure that uses a combination of hydrochloric acid treatments and abrasion to remove the cement paste from the aggregate. This extracted aggregate was then crushed down to the specified sizes and used …

Ceas E-News 12.11.2007, College Of Engineering And Applied Sciences

College of Engineering and Applied Sciences News

Winners of 2007 Spring AutoCAD Contest honored in fall lecture class

On The Stability Of Region Count In The Parameter Space Of Image Analysis Methods, Li Yu

All Dissertations

In this dissertation a novel bottom-up computer vision approach is proposed. This approach is based upon quantifying the stability of the number of regions or count in a multi-dimensional parameter scale-space. The stability analysis comes from the properties of flat areas in the region count space generated through bottom-up algorithms of thresholding and region growing, hysteresis thresholding, variance-based region growing. The parameters used can be threshold, region growth, intensity statistics and other low-level parameters. The advantages and disadvantages of top-down, bottom-up and hybrid computational models are discussed. The approaches of scale-space, perceptual organization and clustering methods in computer vision are …

Seismic Fragility Curves For A Typical Highway Bridge In Charleston, Sc Considering Soil-Structure Interaction And Liquefaction Effects, Matthew Bowers

All Theses

Evidence from historical earthquakes suggests that the vulnerability of highway bridges is significantly affected by large permanent ground deformations caused by liquefaction as well as soil-structure interaction (SSI). The vulnerability of a typical multi-span simply-supported (MSSS) concrete girder bridge found in Charleston, South Carolina, is evaluated with consideration for liquefaction and SSI effects. In general, existing bridges in this region were not originally designed with consideration for seismic events or liquefaction of underlying soils. Fragility curves that represent the probability of exceeding predefined performance levels of damage given an earthquake of a particular intensity are used to evaluate the effects …

Fate And Transport Of Pathogen Indicators From Pasturelands, Michelle L. Soupir

Michelle L. Soupir

The U.S. EPA has identified pathogen indicators as a leading cause of impairments in rivers and streams in the U.S. Elevated levels of bacteria in streams draining the agricultural watersheds cause concern because they indicate the potential presence of pathogenic organisms. Limited understanding of how bacteria survive in the environment and are released from fecal matter and transported along overland flow pathways results in high uncertainty in the design and selection of appropriate best management practices (BMPs) and in the bacterial fate and transport models used to identify sources of pathogens.

The overall goal of this study was to improve …

Morphological Charts: A Systematic Exploration Of Qualitative Design Space, Gregory Smith

All Theses

A morphological chart is a tool that represents a large qualitative design space. These charts list the functions identified for the design problem, and the means (solutions) that can perform each function. Combining one means for each function will produce a potential integrated conceptual design solution. Repeating this process with every possible combination contained in the morphological chart will generate a long list of conceptual design solutions. Not all of these solutions will be practical, or even physically possible.
As it is difficult to analyze a long list of design solutions and as at present, there are no systematic design …

Mixed Convective Heat Transfer And Evaporation At The Air-Water Interface, Prasad Gokhale

All Theses

Functional forms for mixed convective heat transfer and evaporation from an air-water interface were obtained. To obtain these functions, heat transfer and evaporation rates from the air-water interface of an evaporating body of water were quantified in a wind/water tunnel in the presence of an oleyl alcohol monolayer on the water surface. The Nusselt (Nu) and Sherwood (Sh) numbers, parameterizing the dimensionless heat and mass transfer respectively, for transport from the water bulk to air were expressed as functions of the air side Rayleigh (Ra) and Reynolds (Re) numbers. The Nu and Sh were calculated for a range of Ra …

Investigation Into Mitigation Of Alkali-Silica Reaction Using Selected Scms In Presence Of Potassium Acetate Deicer, Jigar Desai

All Dissertations

Alkali-silica reaction (ASR) is one of the most recognized durability problems in concrete leading to premature deterioration of different types of concrete structures. Recent investigation into premature deterioration of airfield concrete pavements indicated the aggressive effects of alkali-acetate and alkali-formate based deicers on concrete containing marginal aggregates, in particular on their potential to induce ASR.. This dissertation presents the results and analysis from a research study conducted to evaluate the effectiveness of selected supplementary cementitious materials-SCMs (fly ash and slag) as ASR mitigation measures in presence of potassium acetate based deicer.
Five aggregates that encompass a range of mineralogies and …

A Comparative Fault Diagnosis Methodology Based On Time Series Analysis Of System's Signals, Hany Bassily

All Dissertations

The detection of system anomalies represents an important task in safety critical systems. Over the past two decades, advances in data manipulation techniques and sensor technology have contributed to the widespread application of signal processing concepts for fault diagnosis. However, the majority of these signal processing, or data driven, diagnostics do not possess the redundancy level exhibited in conventional model-based methods. Among signal processing methods, time series analysis is advantageous since it offers insight into the underlying dynamics and forecasts system behavior. Furthermore, the data driven method allows the depiction of system dynamics with an increased level of redundancy. This …

Ultrahydrophobic Surface Modification Of Polymeric Fibers And Inorganic Substrates, Karthik Ramaratnam

All Dissertations

The wettability of a solid surface is a very important property, and is governed by both the chemical composition and the geometrical microstructure of the surface. Wettability and repellency are important properties of solid surfaces from both fundamental and practical aspects. The wettability of the solid surface is a characteristic property of materials and strongly depends on both the surface energy and the surface roughness. These properties may be approached by mimicking hydrophobic structures created by nature on lotus leaf surface. The lotus effect is based on surface roughness caused by different microstructures together with the hydrophobic properties of the …

Effect Of Carbon Nanofibers On Microstructure And Properties Of Polymer Nanocomposites, Sungho Lee

All Dissertations

Nano-modifiers are typically three orders of magnitude smaller in size than their micro-counterparts. At this scale, interactions between matrix molecules and the nano-modifiers can lead to novel physical and chemical properties of the resulting nanocomposites. Carbon nanofibers (CNFs) are a class of nano-modifiers that has received significant attention recently because they have superior electrical conductivity and mechanical properties with a high aspect ratio (length over diameter). Several recent research studies have focused on enhancing electrical and mechanical performance of composites in the presence of CNFs. However, the influence of CNFs on the structure of the polymer matrix is important in …

Sediment Transport Upstream Of Orifices, David Powell

All Dissertations

Sediment transport upstream of orifices has not been studied outside the realm of the restoration of reservoir storage capacity. This experimental study used a large basin with a circular orifice outlet and a movable sand bed leveled with the invert of the orifice. Three sizes of non-cohesive, uniform sand were used with d₅₀ values of 0.29mm, 0.72mm, and 0.89mm. Bed profiles at equilibrium scour conditions were measured for three different head levels for each sediment size. The maximum scour depth, length, and scour width were related to the particle size and the available head. The longitudinal and lateral extents …

Multi-Objective Generation Scheduling With Hybrid Energy Resources, Manas Trivedi

All Dissertations

In economic dispatch (ED) of electric power generation, the committed generating units are scheduled to meet the load demand at minimum operating cost with satisfying all unit and system equality and inequality constraints. Generation of electricity from the fossil fuel releases several contaminants into the atmosphere. So the economic dispatch objective can no longer be considered alone due to the environmental concerns that arise from the emissions produced by fossil fueled electric power plants. This research is proposing the concept of environmental/economic generation scheduling with traditional and renewable energy sources. Environmental/economic dispatch (EED) is a multi-objective problem with conflicting objectives …

Techniques For Improving The Performance Of Coupled Oscillator Arrays, Venkatesh Seetharam

All Dissertations

Coupled oscillator arrays (COAs) have excellent synchronization properties that can be utilized to develop a low cost alternative to phased array systems for beam steering applications. The primary concerns in implementing the COA architecture are the sensitivity to cell-to-cell component variation and poor phase noise performance. Wide injection locking range oscillators reduce the sensitivity to component variation but degrade the array phase noise performance. The objective of this dissertation is to alleviate the concerns hindering the application of COAs by employing techniques to realize COAs with wide mutual injection locking ranges (MILR), improved phase noise characteristics and beam steering capabilities. …

An Experimental And Numerical Study Of The Film Casting Process, Kenneth Aniunoh

All Dissertations

Film casting is a common industrial process used to produce polymeric films. During film casting, a polymer melt is extruded through a flat die before rapid cooling on a chill roll. The chill roll velocity is faster than the velocity at which the melt exits the die, thus the polymer melt is stretched and oriented in an extensional flow. The material properties and processing conditions have a significant impact on the process and the final thermal/mechanical properties of the film produced.
Optimization of industrial scale film casting processes is still greatly dependent on trial and error methods. Therefore, this work …