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Full-Text Articles in Engineering

Nonlinear Energy Harvesting Under White Noise, Qifan He Nov 2013

Nonlinear Energy Harvesting Under White Noise, Qifan He

All Theses

While purposeful introduction of stiffness nonlinearities into the dynamics of energy harvesters is aimed at enhancing performance under non-stationary and random excitations, most of the conclusions reported in the current literature are based on the steady-state response which assumes a harmonic fixed-frequency excitation. As a result, we still do not have a clear understanding of how the nature of the excitation influences the output power, or what role stiffness nonlinearities play in the transduction of energy harvesters under random excitations. To fill this gap in the current knowledge, this thesis investigates the response of nonlinear mono- and bi-stable energy harvesters …


Finite Element Analysis Of Effective Mechanical Properties, Vibration And Acoustic Performance Of Auxetic Chiral Core Sandwich Structures, Hrishikesh Joshi Aug 2013

Finite Element Analysis Of Effective Mechanical Properties, Vibration And Acoustic Performance Of Auxetic Chiral Core Sandwich Structures, Hrishikesh Joshi

All Theses

Honeycomb cellular materials are widely used in engineering applications due to their high strength to weight ratio and controllable effective mechanical properties. The effective properties are controlled by varying the geometry of the repetitive unit cells of honeycomb structure. Sandwich panels made of honeycomb cores are beneficial in many applications including vibration isolation and sound transmission reduction. Sandwich panels with standard honeycomb core configurations have previously been studied with regards to sound transmission behavior. It has been established that the auxetic honeycomb cores, having negative in-plane Poisson's ratio, exhibit higher sound transmission loss as compared to regular honeycomb cores. In …


Statistical Regression Methods For Gpgpu Design Space Exploration, Nimisha Raut Aug 2013

Statistical Regression Methods For Gpgpu Design Space Exploration, Nimisha Raut

All Theses

General Purpose Graphics Processing Units (GPGPUs) have leveraged the performance and power efficiency of today's heterogeneous systems to usher in a new era of innovation in high-performance scientific computing. These systems can offer significantly high performance for massively parallel applications; however, their resources may be wasted due to inefficient tuning strategies. Previous application tuning studies pre-dominantly employ low-level, architecture specific tuning which can make the performance modeling task difficult and less generic. In this research, we explore the GPGPU design space featuring the memory hierarchy for application tuning using regression-based performance prediction framework and rank the design space based on …


Impact Of Channel Conditions On Existing Scour Measuring Instruments, Md Nasimul Hoque Chowdhury Aug 2013

Impact Of Channel Conditions On Existing Scour Measuring Instruments, Md Nasimul Hoque Chowdhury

All Theses

Scour around bridge piers and abutments, is the prominent reason for bridge failures. Bridge failures have substantial effects on economy and human lives. About 60% of the total bridge failures in U.S. can be attributed to scour. In the past, scour has been responsible for several million dollars in bridge repair cost. Given the threat to the bridge infrastructure due to scour, the U.S. Federal Highway Administration has proposed several countermeasures to reduce the impact of bed degradation. One of these countermeasures that is particularly relevant during peak flow periods is the real-time scour monitoring. Scour monitoring involves real-time data …


Computational Representation Of Linguistic Semantics For Requirement Analysis In Engineering Design, Alex Lash Aug 2013

Computational Representation Of Linguistic Semantics For Requirement Analysis In Engineering Design, Alex Lash

All Theses

The objective of this research is to use computational linguistics to identify semantic implicit relationships between text-based relationships. Specifically, natural language processing is used to implement linguistic semantics in requirement analyzers. Linguistic semantics is defined as the meaning of words beyond their string form, part of speech, and syntactic function. Many existing design tools use part of speech tagging and sentence parsing as the foundation of their requirement analysis but ultimately use string algorithms to evaluate requirements. These string algorithms cannot capture the implicit knowledge in requirements. This research compares five methods of requirement analysis. A manual analysis provides the …


Improved Photolithography Scheduling In Semiconductor Manufacturing, Sreenath Chalil Madathil Aug 2013

Improved Photolithography Scheduling In Semiconductor Manufacturing, Sreenath Chalil Madathil

All Theses

Photolithography is typically the bottleneck process in semiconductor manufacturing. In this thesis, we present a model for optimizing photolithography job scheduling in the presence of both individual and cluster tools. The combination of individual and cluster tools that process various layers or stages of the semiconductor manufacturing process flow is a special type of flexible flowshop. We seek separately to minimize total weighted completion time and maximize on-time delivery performance. Experimental results suggest that our mathematical- and heuristic-based solution approaches show promise for real world implementation as they can help to improve resource utilization, reduce job completion times, and decrease …


Removal Of Arsenic From Simulated Groundwater Using A Pilot-Scale Constructed Wetland Treatment System, Jeffrey Schwindaman Aug 2013

Removal Of Arsenic From Simulated Groundwater Using A Pilot-Scale Constructed Wetland Treatment System, Jeffrey Schwindaman

All Theses

A pilot-scale constructed wetland treatment system (CWTS) was designed and built to produce biogeochemical conditions that promoted targeted processes for removal of arsenic from simulated groundwater. Two series were designed to promote co-precipitation and sorption of arsenic with iron oxyhydroxides under oxidizing conditions, and two series were designed to promote precipitation of arsenic sulfide and co-precipitation of arsenic with iron sulfide under reducing conditions. The two major objectives were to (1) assess arsenic removal performance and (2) determine the fate and distribution of arsenic in each series. Results indicate that arsenic removal performance was greater in series designed to promote …


Data Driven, Performance Based Parking Management In A University Setting, Brian Maleck Aug 2013

Data Driven, Performance Based Parking Management In A University Setting, Brian Maleck

All Theses

With university enrollment increasing, campuses are becoming under increased strain for parking. More students results in more cars on an already stressed parking infrastructure. In many instances, university parking management offices are being asked to accommodate this increase in parking without the construction of new parking infrastructure. In order to accommodate these demands, better parking management is required.
This research develops a framework to evaluate current parking management practices and pinpoint methods to improve upon current practices. The framework is generalized for use by any size and type of university. Clemson University's campus in Clemson, SC was used as a …


Particle Electrophoresis And Magnetophoresis In Microchannels, Litao Liang Aug 2013

Particle Electrophoresis And Magnetophoresis In Microchannels, Litao Liang

All Theses

In current pharmaceutical and biotechnology industries with clinical applications, an increased demand for flow control and cell manipulation on the micrometer scale has emerged. Electrokinetic, magnetic and many other physics fields have been exploited to meet this demand. However, due to the requirement for sophisticated micro-structures and the interference of the increasing significance of many `trivial' physics properties (surface potential, permittivity, etc.) at the smaller scale, most applications encounter poor maneuverability and high operation/fabrication complexity issues. Very few attempts have been made to bypass these requirements while maintaining the same control and efficiency. This thesis research investigates the fundamental behaviors …


Comparison Of Methods To Evaluate Chitosan As An Antimicrobial Against Listeria Spp. Cultures, Scott Hartley Aug 2013

Comparison Of Methods To Evaluate Chitosan As An Antimicrobial Against Listeria Spp. Cultures, Scott Hartley

All Theses

The antimicrobial properties of a chitosan-coated vacuum-packaged pouch were tested against Listeria monocytogenes (LM) inoculated on frankfurters. A 1.5% chitosan solution was successfully coated onto a corona-treated poly/nylon based film and then heat-sealed to form a pouch. An initial 5 log CFU/mL population of LM was used to inoculate a frankfurter in the pouch, which was then vacuum-sealed and stored at 4¡ and 13¡ C for a period of 8 weeks, with bacteria enumeration performed on weekly intervals. An uncoated pouch was tested as a control. It was found that the chitosan-coated pouches did not exhibit any antimicrobial properties against …


Air Pressure Energy Storage For Reverse Osmosis: Bench-Scale Proof Of Concept, Ying Sun Aug 2013

Air Pressure Energy Storage For Reverse Osmosis: Bench-Scale Proof Of Concept, Ying Sun

All Theses

Society faces diminishing access to clean drinking water because of increasing global population and the development of modern industries. At the same time, climate change and other environmental problems caused by the increase in fossil fuel consumption the emphasis on reducing dependency on traditional energy resources in the process of potable water production. To address both problems, a small-scale wind powered reverse osmosis (RO) desalination system with a unique energy storage mechanism was envisioned to provide an energy buffer such that fluctuating and intermittent wind can be utilized. Energy is stored in the form of compressed air in a pressure …


Thermo-Mechanical Effects Of Thermal Cycled Copper Through Silicon Vias, James Marro Aug 2013

Thermo-Mechanical Effects Of Thermal Cycled Copper Through Silicon Vias, James Marro

All Theses

The semiconductor industry is currently facing transistor scaling issues due to fabrication thresholds and quantum effects. In this 'More-Than-Moore' era, the industry is developing new ways to increase device performance, such as stacking chips for three-dimensional integrated circuits (3D-IC). The 3D-IC's superior performance over their 2D counterparts can be attributed to the use of vertical interconnects, or through silicon vias (TSV). These interconnects are much shorter, reducing signal delay. However TSVs are susceptible to various thermo-mechanical reliability concerns. Heating during fabrication and use, in conjunction with coefficient of thermal expansion mismatch between the copper TSVs and silicon substrate, create harmful …


Effectiveness Of Display Trays On Attention And Purchase Of Consumer Products, Erin Snyder Aug 2013

Effectiveness Of Display Trays On Attention And Purchase Of Consumer Products, Erin Snyder

All Theses

Through the collection of qualitative and quantitative data, consumer perception and preference of display trays in the retail environment was examined and evaluated. Purchase decision and eye-tracking data was collected, as well as qualitative survey information, to determine if participants favored packages in a display tray opposed to packages placed directly on store shelving. This preference was measured in terms of time to first fixation, total fixation duration, fixation count as well as final purchasing decision. The experiment analyzed liquid dish soap and canned tomatoes, and was organized as a 2 (products per category) x 1 (display tray per category) …


The Development Of A Rapid Fiber-Based Immunoassay As A Point-Of-Care Or In-Home Diagnostic Test, Christopher Waddell Aug 2013

The Development Of A Rapid Fiber-Based Immunoassay As A Point-Of-Care Or In-Home Diagnostic Test, Christopher Waddell

All Theses

Early diagnosis of conditions allows for physicians to treat patients earlier, and ultimately improve patient outcomes. Two conditions of particular interest for earlier and cheaper diagnosis are the influenza virus and human immunodeficiency virus (HIV). Antiviral treatment administered within the first 48 hours of influenza infection decreases symptom severity, risk of complications, and reduced healthcare costs. Early diagnosis of HIV can decrease the risk of transmission of the virus to HIV negative individuals and allow for earlier administration of highly active antiretroviral treatment (HAART), improving patient quality of life and patient outcomes.
Currently, the 'gold standard' for detection of both …


Evaluation Of Anaerobic Biodegradation Of High Concentrations Of Halogenated Methanes, Priya Rachel Jacob Aug 2013

Evaluation Of Anaerobic Biodegradation Of High Concentrations Of Halogenated Methanes, Priya Rachel Jacob

All Theses

Removal of the chlorinated methanes, carbon tetrachloride (CT), chloroform (CF) and dichloromethane (DCM), and the halogenated methane, trichlorofluoromethane (commonly known as CFC-11 or Freon-11) from contaminated soil and groundwater remains challenging. Releases to the environment resulted from historically poor disposal practices, as well as spills and leaks from underground storage tanks. Among these three compounds, CF is considered the benchmark for evaluating the feasibility of bioremediation, due to its typically high level of toxicity towards most anaerobic prokaryotes. However, inhibitory effects of low concentrations of CFC-11 on anaerobes have been reported as well. Bioremediation is an attractive option for clean-up, …


Probabilistic Back Analysis Of Geotechnical Systems, Lei Wang Aug 2013

Probabilistic Back Analysis Of Geotechnical Systems, Lei Wang

All Theses

This thesis is aimed at applying the probabilistic approaches for back analysis of geotechnical systems. First, a probabilistic back-analysis of a recent slope failure at a site on Freeway No. 3 in northern Taiwan is presented. The Markov Chain Monte Carlo (MCMC) simulation is used to back-calculate the geotechnical strength parameters and the anchor force. These inverse analysis results, which agree closely with the findings of the post-event investigations, are then used to validate the maximum likelihood method, a computationally more efficient back-analysis approach. The improved knowledge of the geotechnical strength parameters and the anchor force gained through the probabilistic …


Problems In The Study And Use Of Ac Dielectrophoresis And Their Consequences: A Study Based On Comsol Multiphysics Modeling, Vandana Devi Pandian Babu Aug 2013

Problems In The Study And Use Of Ac Dielectrophoresis And Their Consequences: A Study Based On Comsol Multiphysics Modeling, Vandana Devi Pandian Babu

All Theses

Dielectrophoresis (or DEP) is an important phenomenon which is induced when a dielectric particle is placed in a non-uniform electric field. The force generated by DEP has been exploited for various micro and nano fluidics applications like positioning, sorting and separation of particles involved in medical diagnostics, drug discovery, cell therapeutics, biosensors, microfluidics, nanoassembly, particle filtration etc. The integration of DEP systems into the microfluidics enables inexpensive, fast, highly sensitive, highly selective, label-free detection and also the analysis of target bioparticles.

This work aims to provide a complete compilation of the factors affecting the DEP force. It elucidates the underlying …


Biological Production Of Succinic Acid Using A Cull Peach Medium, Janani Krishnakumar Aug 2013

Biological Production Of Succinic Acid Using A Cull Peach Medium, Janani Krishnakumar

All Theses

Biological production of succinic acid from a cull peach based medium was studied using Escherichia coli AFP 184 in a dual-phase batch process including an aerobic growth phase and an anaerobic production phase. Experiments were performed to study the effects of corn steep liquor supplement and exogenous hydrogen supply. About one half of the sucrose in the medium was converted to fermentable sugars glucose and fructose during sterilization. The remaining sucrose was hydrolyzed with invertase. The viscosity of the medium was reduced from 350 cP to 50 cP to allow efficient oxygen transfer by a commercial enzyme product. In the …


Novel Side-Vent-Channel Based Blast Mitigation Concept For Light Tactical Vehicles, Ramin Yavari Aug 2013

Novel Side-Vent-Channel Based Blast Mitigation Concept For Light Tactical Vehicles, Ramin Yavari

All Theses

A new concept solution for improving survivability of the light tactical military vehicles to blast-loads resulting from a shallow-buried mine detonated underneath such vehicles is proposed and critically assessed using computational engineering methods and tools. The solution is inspired by the principle of operation of the rocket-engine nozzles, in general and the so called 'pulse detonation' rocket engines, in particular, and is an extension of the recently introduced so-called 'blast chimney' concept (essentially a vertical channel connecting the bottom and the roof and passing through the cabin of a light tactical vehicle).
Relative to the blast-chimney concept, the new solution …


An Analysis Of A Missing Design Concept For Sustainable Buildings: Addressing The Safety And Health Of The Construction Worker, Christopher Almond Aug 2013

An Analysis Of A Missing Design Concept For Sustainable Buildings: Addressing The Safety And Health Of The Construction Worker, Christopher Almond

All Theses

Construction work is inherently dangerous. The 2010 U.S. Bureau of Labor Statistics show the construction industry had the most fatal injuries of all industry sectors, 17%. U.S. regulations place the responsibility for construction safety on the construction contractor. However, owners and designers have the potential to affect the safety of the construction workforce. Owners have gotten more involved in promoting the safety and health of construction workers in recent years; however, studies show that the safety and health of the construction workforce is not typically considered by designers.
The Naval Facilities Engineering Command (NAVFAC) - the U.S. Navy's systems command …


Improved Iterative Detection Techniques For Slow-Frequency-Hop Communications With Reed-Solomon Codes, Madhabi Manandhar Aug 2013

Improved Iterative Detection Techniques For Slow-Frequency-Hop Communications With Reed-Solomon Codes, Madhabi Manandhar

All Theses

The performance of a packet-level iterative detection technique is examined for a slow-frequency-hop packet radio system using interleaved Reed-Solomon codes and per-dwell differential encoding. A per-dwell soft-input-soft-output detector along with successive-erasures decoding results in a system that performs better than previously considered detection techniques in the presence of partial-band interference. The log-MAP algorithm and two forms of its max-log-MAP approximation are considered for the soft-input-soft-output detector along with different channel estimators. The performance and detection complexity of the systems is compared. A limit on the number of erasures allowed in successive-erasures decoding is also considered, and its effect on the …


Experimental Development And Analysis Of A Novel Setup For Insulated Dielectrophoresis, Johnie Hodge Aug 2013

Experimental Development And Analysis Of A Novel Setup For Insulated Dielectrophoresis, Johnie Hodge

All Theses

Dielectrophoresis has long been studied and utilized for the manipulation of microscale particles in solution. This phenomenon is due to the induced polarization of dielectric particles subjected to an electric field. When the field is also inhomogeneous in terms of the distribution of its strength through space, the polarized particles move and come to rest in certain areas due to the relationship between their and the solvent's relative permittivities. If the electric field is homogenous, such as within a parallel plate capacitor, the particles are polarized according to their permittivity and the field's frequency, but they will not move.
These …


Describing Plutonium Contamination Issues In Hanford Soils: Development Of A Thermodynamic Surface Complexation Model, Sarah Herr Aug 2013

Describing Plutonium Contamination Issues In Hanford Soils: Development Of A Thermodynamic Surface Complexation Model, Sarah Herr

All Theses

The development of remediation strategies for long-term site management requires knowledge of an actinide's geochemical behavior. Understanding this behavior can lead to the formation of a subsurface transport model. For example, plutonium mobility in the subsurface environment is significantly influenced by oxidation-reduction and complexation reactions. This work considered the surface-mediated reduction of plutonium, as well as the hydrolysis and carbonate complexation of the actinide.
Evaluating the significance of these reactions required several variable pH batch sorption studies. Experiments incorporated plutonium and neptunium sorption to sediments from the Hanford Nuclear Reservation in Washington State. Two different sediments were examined: coarse-grained and …


Flexural Strength Reliability Of Visually Graded Southern Pine Dimensional Lumber, Mengyu Yang Aug 2013

Flexural Strength Reliability Of Visually Graded Southern Pine Dimensional Lumber, Mengyu Yang

All Theses

The reference design values published in the National Design Specification (NDS) for Wood Construction are derived from full-scale testing of lumber samples performed in the 1980s. This testing program is commonly known as the In-GradeTest Program. Selective annual sample tests of visually graded Southern Pine lumber from 1994 to 2010 revealed an overall decreasing trend in the mechanical properties. Because of this alarming observation, a new round of full-scale In-Grade test of visually graded Southern Pine was initiated in 2010. The new test data indicated significant reductions in certain design values published in the current design code (2005 NDS). …


Removal Of N-Nitrosodimethylamine And Trihalomethane Precursors With Powdered Activated Carbon, Wilson Beita Sandi Aug 2013

Removal Of N-Nitrosodimethylamine And Trihalomethane Precursors With Powdered Activated Carbon, Wilson Beita Sandi

All Theses

N-nitrosodimethylamine (NDMA) has been used commercially in several applications, including the production of liquid rocket fuel, and a variety of foods, but gained more relevance when it was discovered as a drinking water disinfection by-product (DBP) in 1989. NDMA is a probable human carcinogen with 10-6 lifetime cancer risk associated with a drinking water concentration of 0.7 ng/L, and is listed as a priority pollutant in the Code of Federal Regulations; no federal maximum contaminant level has been established for drinking water yet. However, the United States Environmental Protection Agency is planning to make a preliminary regulatory determination in 2013 …


Hydrogen Production By Thermotoga Lettingae Using Spent Fermentation Media Containing Acetic Acid, Archana Ganesh Aug 2013

Hydrogen Production By Thermotoga Lettingae Using Spent Fermentation Media Containing Acetic Acid, Archana Ganesh

All Theses

Biological production of hydrogen (H2) gas from fermentation of agricultural feedstock is one method to produce clean and sustainable source of energy. During fermentation of glucose to H2, acetic acid and carbon dioxide (CO2) by Thermotoga neapolitana, only 33% of the energy contained in glucose is converted to hydrogen. The aim of this study was to use a second thermotogale, Thermotoga lettingaeto ferment sugars and acetic acid in spent media to produce H2. Hydrogen production by this bacterium in fresh and spent media was studied by quantifying the amount of …


Improvement Of Onsite Wastewater Treatment By Use Of Electrically Conductive Carbon Cloth, Christopher Weber Aug 2013

Improvement Of Onsite Wastewater Treatment By Use Of Electrically Conductive Carbon Cloth, Christopher Weber

All Theses

The purpose of this research is primarily focused on carbon oxidation in domestic septic systems. Small-scale septic waste reactors utilizing electrically conductive carbon cloth were assessed for improving carbon oxidation and therefore the overall efficiency of on-site wastewater treatment systems.
A bioelectrochemical system was developed to enhance carbon oxidation in septic systems using electrically conductive carbon cloth as an anode/cathode bridge to transfer electrons from strictly anoxic septic wastewater to an oxic system outside of the septic reactor. This 'septic snorkel' (so named since the system 'breathes' via the carbon cloth extends into an aerobic zone) was designed to lower …


Modeling Benefits Of Implementing Low Impact Development Practices Within Forecasted Growth Scenarios Of The Reedy River Watershed, Stephen Taylor Aug 2013

Modeling Benefits Of Implementing Low Impact Development Practices Within Forecasted Growth Scenarios Of The Reedy River Watershed, Stephen Taylor

All Theses

For this research, a previously developed comprehensive watershed water quality model for the Reedy River as developed for South Carolina Department of Health and Environmental Control (SCDHEC) and the US Environmental Protection Agency (EPA) as a total maximum daily load (TMDL) assessment tool was used to assess the benefits of using low impact development (LID) designs in future growth of Greenville County, within the Reedy River watershed. The original intent of this model was to provide SCDHEC with a defensible model that could be used to prepare nutrient TMDLs for an area located at Boyd Millpond and the Reedy River …


Application Of Parameter Estimation And Calibration Method For Car-Following Models, Md Rahman Aug 2013

Application Of Parameter Estimation And Calibration Method For Car-Following Models, Md Rahman

All Theses

Both safety and the capacity of the roadway system are highly dependent on the car-following characteristics of drivers. Car-following theory describes the driver behavior of vehicles following other vehicles in a traffic stream. In the last few decades, many car-following models have been developed; however, studies are still needed to improve their accuracy and reliability.
Car-following models are a vital component of traffic simulation tools that attempt to mimic driver behavior in the real world. Microscopic traffic simulators, particularly car-following models, have been extensively used in current traffic engineering studies and safety research. These models are a vital component of …


Effect Of Differential Movement Of Straight Reinforcing Bars During Early Age Curing On The Bond Strength, Tyler Andrews Aug 2013

Effect Of Differential Movement Of Straight Reinforcing Bars During Early Age Curing On The Bond Strength, Tyler Andrews

All Theses

As the nation's infrastructure continues to age, the number of structural deficiencies is rising. Accordingly, there is a great need and desire to replace these failing components in a quick and efficient fashion. Prefabricated elements for structures such as bridges and parking decks are commonly implemented in this process in order to save both time and money. These prefabricated elements are often subjected to moving live loads during construction and repair which, consequently, result in differential movements occurring across the joints connecting the elements of these structures. Potential reductions in joint capacity, joint stiffness, and structural durability are the byproducts …