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Articles 1 - 30 of 102
Full-Text Articles in Engineering
Determining Transverse Design Forces For A Next-D Bridge Using 3d Finite Element Modeling, Robert Funcik
Determining Transverse Design Forces For A Next-D Bridge Using 3d Finite Element Modeling, Robert Funcik
All Theses
This thesis looks into the use of 3D Finite Element Modeling to determine the transverse design forces for short-span bridges built using the Northeast Extreme Tee with integral deck (NEXT-D) beam. Models were built using either solid elements or shell elements to represent the bridge deck, and the results were compared. The stiffness of the shear keys were taken into account during the modeling process. Results were compared to the AASHTO strip width method for design bridge decks, and the results showed that the strip width method would not be adequate for the design of NEXT-D bridges, so specific live …
Temporal Pier Scour Evolution Under Stepped Hydrographs, Mark Schillinger
Temporal Pier Scour Evolution Under Stepped Hydrographs, Mark Schillinger
All Theses
The present study was aimed at measuring the scour hole profile at bridge piers under clear water scour. Scour tests were performed under both steady state flow and under stepped hydrographs. Multiple smaller flood events were run to determine how flood history affects scour hole development. Various equilibrium scour depth equations and proposed temporal scour models were compared. The similarity of the scour hole profiles with time and flow history were evaluated.
Experiments were conducted in a 14.8 m long, 1.19 m wide, 1.22 m deep rectangular flume with a model bridge pier. A uniform sediment bed (d50= …
Analysis And Implementation Of Room Assignment Problem And Cannon's Algorithm On General Purpose Programmable Graphical Processing Units With Cuda, Harsh Vardhan Dwivedi
Analysis And Implementation Of Room Assignment Problem And Cannon's Algorithm On General Purpose Programmable Graphical Processing Units With Cuda, Harsh Vardhan Dwivedi
All Theses
General-purpose Graphics Processing Units (GP-GPU) has emerged as a popular computing paradigm for high-performance computing over the last few years. The increased interest in GP-GPUs for parallel computing mirrors the trend in general computing with the rise of multi-core processors as an alternative approach to increase processor performance. Many applications that were previously accelerated on distributed processing platforms with MPI or multithreaded techniques such as OpenMP are now being investigated to assess their performance on GP-GPU platforms. Since the GP-GPU platform is designed to give higher performance for parallel problems, applications on other parallel architectures are good candidates for performance …
A Computational Investigation For Potential Improvements, Angela Grujicic
A Computational Investigation For Potential Improvements, Angela Grujicic
All Theses
Mild traumatic brain injury (mTBI), colloquially known as a concussion, is the most common injury in modern wars. This domination of mTBI is hypothesized to be due to a combination of unconventional explosives and better protection and care of the patients, increasing survivability. While the majority of the body is covered in armor, the head is left relatively unprotected. The current Advanced Combat Helmet (ACH) has been designed to protect the warfighter against ballistic impacts and impacts against a hard surface, with little to no regard to blast loading. Polyureas, a class of microsegregated, elastomeric copolymers, has been shown to …
An Early Warning Monitoring System For Cnc Spindle Bearing Failure, Andrew Werner
An Early Warning Monitoring System For Cnc Spindle Bearing Failure, Andrew Werner
All Theses
Equipment employed in a manufacturing environment must be able to operate as long as possible having as little downtime as possible. Therefore, maintenance is crucial in order to allow for the equipment to perform its designated tasks without failure, especially on critical systems. In a CNC machine, if the spindle fails, the machine is useless. Having the ability to detect spindle degradation to the point where a replacement spindle installation can be planned, via condition monitoring, is invaluable to a manufacturer who utilizes these types of machines.
An early warning monitoring system for CNC spindle bearing failure has been developed …
Measuring Digital System Latency From Sensing To Actuation At Continuous 1 Millisecond Resolution, Weixin Wu
Measuring Digital System Latency From Sensing To Actuation At Continuous 1 Millisecond Resolution, Weixin Wu
All Theses
This thesis describes a new method for measuring the end-to-end latency between sensing and actuation in a digital computing system. Compared to previous work, which generally measures the latency at 16-33 ms intervals or at discrete events separated by hundreds of ms, our new method measures the latency continuously at 1 millisecond resolution. This allows for the observation of variations in latency over sub 1 s periods, instead of relying upon averages of measurements. We have applied our method to two systems, the ?rst using a camera for sensing and an LCD monitor for actuation, and the second using an …
Printing Carbon Nanotube Based Supercapacitors For Packaging, Alexandra Hartman
Printing Carbon Nanotube Based Supercapacitors For Packaging, Alexandra Hartman
All Theses
Living in a world full of portable electronics, there is great need for energy storage devices. Currently, limitations for storage involve power inefficiencies as well as bulkiness. This is why printable charge storage devices that display good electrochemical performance are needed. It is for this reason that research into the production and packaging of carbon nanotube based super capacitors was carried out.
A super capacitor can be built by using high surface area multi-walled carbon nanotubes suspended in an ionic liquid. The two active electrodes are made from a combination of the multi-walled carbon nanotubes and an ionic liquid, ground …
Empirical Study: Failure Of Glass-To-Metal Seals During Shock Loading, William Horton
Empirical Study: Failure Of Glass-To-Metal Seals During Shock Loading, William Horton
All Theses
The goal of this thesis was to determine the empirical failure mechanisms and sequence of cartridge actuated devices (CADs) experiencing failure of the glass-to-metal (G/M) seal. Impact loading was conducted with a drop weight machine at room temperature and 300¡F, and then empirically analyzed with high speed video. Resulting peak overload force, shear stress, and impulse were all calculated. The room temperature samples were found to absorb twice the impulse upon failure as the elevated temperature G/M seals. Closed-form and three-dimensional finite element analysis was used to determine the stress state and deformation upon loading. Furthermore, high speed data was …
The Design Of A Haptic Device For Training And Evaluating Surgeon And Novice Laparoscopic Movement Skills, Ryan Bontreger
The Design Of A Haptic Device For Training And Evaluating Surgeon And Novice Laparoscopic Movement Skills, Ryan Bontreger
All Theses
As proper levels of force application are necessary to ensure patient safety, and training hours with an expert on live subjects are difficult, enhanced computer-based training is needed to teach the next generation of surgeons. Considering the role of touch in surgery, there is a need for a device capable of discerning the haptic ability of surgical trainees. This need is amplified by minimally invasive surgical techniques where a surgeon's sense of tissue properties comes not directly through their own hands but indirectly through the tools. A haptic device capable of producing a realistic range of forces and motions that …
Analysis And Parameterization Of The Flight Of Ember Generation Experiments, Hillary Harris
Analysis And Parameterization Of The Flight Of Ember Generation Experiments, Hillary Harris
All Theses
This thesis presents a study on ember flight modeling based on a series of wind tunnel experiments. The purpose of these experiments and the data collected was to provide the input conditions for an ember flight model in order to compare and validate the model predictions. An analysis was performed which determined the sensitivity of model predictions of downwind mass distribution to uncertainties in the model input parameters.
From the wind tunnel experiments, flight distances were measured and characteristic ember size distributions were obtained from the collected data. A flight model was developed based on standard models published in the …
Evaluation Of Bioaugmentation Strategies To Treat High Concentrations Of Chloroform And Carbon Tetrachloride, Han Wang
All Theses
Halogenated methanes, including carbon tetrachloride (CT) and chloroform (CF), are significant groundwater contaminants. Options for bioremediation of high concentrations are limited. Previous studies have shown that an enrichment culture (designated DHM-1) that grows on corn syrup has the potential for use in bioaugmentation. DHM-1 cometabolically biotransforms high concentrations of CT and CF to nontoxic end products (mainly CO, CO2, and organic acids) in the presence of vitamin B12 (approximately 3% of chlorinated methanes on a molar basis). Sulfide is also required by this culture to function properly. However, insufficient data are available on its performance under field conditions. Also, it …
The Performance Of Serial, Matched-Filter Packet Acquisition Using Transmit And Receive Antenna Diversity, Shivram Ramanathan
The Performance Of Serial, Matched-Filter Packet Acquisition Using Transmit And Receive Antenna Diversity, Shivram Ramanathan
All Theses
The performance of serial, matched-filter acquisition is evaluated for asynchronous packet radio communications using transmit or receive antenna diversity. Transmit diversity is achieved using dual antenna transmissions of orthogonal preamble sequences and receive diversity is achieved using dual antenna reception of a single preamble sequence. Sequential test statistics are formed using non-coherent combining of the outputs from the orthogonal preamble matched-filters if transmitter diversity is used; the test statistics are formed using non coherent combining of the outputs from the preamble matched-filter in each receiver chain if receiver diversity is used. Threshold-based acquisition of the test statistics using both fixed …
Robust Design And Monitoring Tools For Sustainable And Resilient Structural Design And Infrastructure Management, Sarah Dalton
Robust Design And Monitoring Tools For Sustainable And Resilient Structural Design And Infrastructure Management, Sarah Dalton
All Theses
Structural systems are subject to inherent uncertainties due to the variability in many hard-to-control `noise factors' that include but are not limited to external loads, material properties, and construction workmanship. Two design methodologies have been widely accepted in the practicing engineering realm to manage the variability associated with operational structures: Allowable Stress Design (ASD) and Load and Resistance Factor Design (LRFD). These traditional approaches explicitly recognize the presence of uncertainty; however, they do not take robustness against this uncertainty into consideration. Overlooking this robustness against uncertainty in the structural design process has two drawbacks. First, the design may not satisfy …
The Effects Of Solvent Mixture On The Thermal And Mechanical Properties Of Solvent Cast Poly-Lactic Acid (Pla) Film, Jeremy Hughes
The Effects Of Solvent Mixture On The Thermal And Mechanical Properties Of Solvent Cast Poly-Lactic Acid (Pla) Film, Jeremy Hughes
All Theses
CH 1 ABSTRACT
The objective of this study was to investigate the effects of various solvents on the crystallinity and thermal expansion stability of PLA film. Three different PLA films were produced by the solvent casting technique; PLA in chloroform (PLA-C), PLA in methylene chloride (PLA-M), and PLA in methylene chloride: acetonitrile = 50: 50 (PLA-MA). The PLA-MA had higher % crystallinity, 46.15, than the PLA-C, 24.03, and the PLA-M, 14.25. With this increase in crystallinity, the PLA-MA had improved thermal expansion stability as shown by very low accumulated dimensional changes at 20-100 ¡C. Wide angle x-ray diffraction identified multiple …
Fault-Tree Model For Bridge Collapse Risk Analysis, Caitlyn Davis-Mcdaniel
Fault-Tree Model For Bridge Collapse Risk Analysis, Caitlyn Davis-Mcdaniel
All Theses
Bridges are vital components of the United States surface transportation infrastructure and, moreover, support the growth of our nation's economy. However, over the past few decades the design capacity and service condition of many bridges in the U.S. has been challenged. Numerous incidents of bridge collapse call for an urgent need to develop a systematic method of assessing the failure risks and identifying the initiating events that can lead to a bridge collapse. This thesis presents a process of bridge failure risk analysis through fault-tree modeling and identification of specific countermeasures, to minimize failure risk, related to structural health monitoring …
Evaluating The Usability Of System-Generated And User-Generated Passwords Of Approximately Minimum Equal Security, Sourav Bhuyan
Evaluating The Usability Of System-Generated And User-Generated Passwords Of Approximately Minimum Equal Security, Sourav Bhuyan
All Theses
System-generated or user-generated text-based passwords are commonly used by the users to authenticate access to their electronic assets. These passwords may vary in usability and memorability depending on the type of password generation, composition and length. However, little past research has compared usability and memorability of passwords, satisfying minimum entropy for a secure password. This study compared three password policy conditions, assigning/generating passwords of approximately equal minimum security, i.e. 6-character alphanumeric system-generated passwords, minimum 8-character restricted user-generated passwords and minimum 16-character unrestricted user-generated passwords.
The study involved 54 participants, equally divided into three groups, 18 in each password policy condition. …
Effect Of Selected Phase Change Materials Concentration And Manufacturing Process On The Properties Of Plaster Mixture Systems, Rong Cui
All Theses
Phase change materials (PCM) are generally used in building construction materials for their ability to absorb and release large amounts of energy when their phase change happens at their specific melting temperature. This results in a significant increase in thermal mass of the building, a reduction in temperature fluctuations and therefore a reduction in heating and cooling loads. However, in order to properly select a PCM and optimize its integration in a specific building, the properties of building construction materials enhanced with PCM must be known. This research focuses on studying the effects of the concentration of a micro-encapsulated PCM …
Chlorine Absorption Utilizing Caustic Sodium Sulfite, Henry Mcdonald
Chlorine Absorption Utilizing Caustic Sodium Sulfite, Henry Mcdonald
All Theses
A scrubber was required to abate a waste stream containing chlorine gas created in the electrolytic dissolution step of the aqueous polishing process at the Mixed Oxides Fuel Fabrication Facility at Savannah River Site, South Carolina. A method of absorption that utilized caustic sodium sulfite as the scrubbing agent was studied for implementation in the process. This method was found to be highly efficient with respect to process requirements, and it was also found to provide enhanced performance over the more conventional method of chlorine scrubbing which uses only aqueous sodium hydroxide as a reagent. Sulfite provides an additional advantage …
Influence Of Pavement Type On Near Surface Air Temperature, David Duncan
Influence Of Pavement Type On Near Surface Air Temperature, David Duncan
All Theses
Effects from an Urban Heat Island (UHI) can be detrimental to the world as a whole. This study examines a collection of permeable and conventional pavements in South Carolina to determine how they relate to near surface air temperatures, which is an indicator of the UHI impact of an area. Three locations were used, each with a different selection of pavement type. Permeable and conventional forms of both asphalt and concrete were tested, as were some open graded friction course samples. Air temperatures were measured and recorded from the pavement surface up to an elevation of 60-in.
Multiple days of …
'Exploring The Potential Of Using Antimicrobial Peptides And Copper Nanoparticles In Tackling Surgical Site Infections', Sriram Sankar
'Exploring The Potential Of Using Antimicrobial Peptides And Copper Nanoparticles In Tackling Surgical Site Infections', Sriram Sankar
All Theses
Postoperative wound site infections remain a major source of illness with approximately 500,000 infections per year, among an estimated 27 million surgical procedures. Such infections account for approximately one quarter of the estimated 2 million nosocomial infections in the United States which causes about 90,000 deaths each year. More than 70% of the bacteria that causes such infections are resistant to at least one of the antibiotics and result in longer hospitalization; besides requiring second option treatments that may be less effective, more toxic and expensive. Hence, there is a frenetic search for alternatives and in this regard, antimicrobial peptides …
Novel Oxadiazole Containing Monomers For Polymeric Light Emitting Devices, Alexandra Foguth
Novel Oxadiazole Containing Monomers For Polymeric Light Emitting Devices, Alexandra Foguth
All Theses
Organic light emitting diodes (OLED) have received a great deal of
attention in the research community in the past few decades. This
work focuses on OLEDs utilizing the donor-acceptor operational
approach. In specific a single layer device architecture with an
emissive layer of copolymerized hole and electron transport moieties
in an effort to frustrate phase segregation that can occur during
device operation. A new methacryalate based oxadiazole monomer,
4-[5-(biphenly-4-yl)- 1,3,4-oxadiazol-2-yl] phenyl methacrylate (mPBD) an electron transporter, was successfully synthesized. The new monomer was copolymerized with N-vinylcarbazole (VK), a hole transporter, to form statistical copolymers. The glass transition of the copolymers …
The Integration Of Building Information Modeling (Bim) Into Civil Engineering Curricula, Jason Cooksey
The Integration Of Building Information Modeling (Bim) Into Civil Engineering Curricula, Jason Cooksey
All Theses
Building Information Modeling (BIM) is an emerging technology used in the Architecture/Engineering/Construction (AEC) industry. The proliferation of BIM usage across the industry has been swift and prolific. Academia has lagged behind the adoption rate of the industry by not producing enough students with BIM exposure. Thus, the question is whether civil engineering curricula should provide an understanding of BIM technology to students entering the design and construction profession. The immediate objective of this research is to determine if it is important to provide exposure of BIM to undergraduate or graduate students in the civil engineering curricula and if so to …
Parallel Implementation Of The Singular Value Decomposition Using Opencl, Bhushan Rayrikar
Parallel Implementation Of The Singular Value Decomposition Using Opencl, Bhushan Rayrikar
All Theses
General-Purpose Graphics Processing Units (GPGPUs) have massively parallel computational capabilities. Low cost and ease of programming make them a popular choice over other parallel architectures such as large clusters and accelerators such as Field-Programmable Gate Arrays (FPGAs). Mature programming frameworks for GPGPUs, such as CUDA from Nvidia and OpenCL from the Khronos Group, reduce the learning curve and development time for programming GPGPU architectures. OpenCL, a relatively new industry standard for parallel computing makes it possible to write a single program for heterogeneous platforms that is portable across multiple platforms including GPGPUs and multi-core processors with minimal coding modifications.
GPGPU …
Product And Process Based Assembly Time Estimation In Engineering Design, Michael Miller
Product And Process Based Assembly Time Estimation In Engineering Design, Michael Miller
All Theses
This thesis presents the research and development of two assembly time estimation techniques for the automotive industry. Both of these techniques are capable of being implemented early in the product life-cycle of a vehicle and require information available in this phase. Currently, assembly time estimation is performed after production has begun and is a tedious manual process requiring hours of motion-time method studies for each assembly activity. The techniques proposed in this thesis can both be performed prior to the start of production and are capable of being performed automatically after the initial mapping.
The first assembly time estimation technique …
In Vitro Study Of Fluid Diodes In The Pulmonary Valve Position, John Porcher
In Vitro Study Of Fluid Diodes In The Pulmonary Valve Position, John Porcher
All Theses
Every year many people suffer from severe chronic pulmonary insufficiency. Problems that can be incurred include the valve becoming stenotic, where it inhibits antegrade flow, and incompetent, allowing retrograde flow. When either of these conditions occurs with great severity, it is often necessary for the native valve to be replaced. There are no acceptable, permanent solutions currently available for a pulmonary valve replacement. Previous research, based on regurgitant fraction and transvalvular gradient, has indicated that a fluid diode could possibly serve as a permanent valve replacement solution. This study investigated the effectiveness of a diode to reduce the workload of …
Development And Application Of A Three-Dimensional Probabilistic Wind-Borne Debris Trajectory Model, James Grayson
Development And Application Of A Three-Dimensional Probabilistic Wind-Borne Debris Trajectory Model, James Grayson
All Theses
This research presents a probabilistic debris trajectory model adapted from current 6-degree-of-freedom (6-DoF) deterministic models, in which the aleatoric (inherent) uncertainty is explicitly considered in the proposed probabilistic model. While the inherent randomness in the debris flight trajectory is irreducible due to the wind turbulence, variation in wind direction, gustiness of the wind event and so forth, the proposed probabilistic model seeks to address these uncertainties through Monte Carlo simulations with the appropriate statistical distributions applied to the governing equations of motion of the debris. Verification of the probabilistic debris trajectory model is performed through an analytical and visual comparison …
Fabrication And Characterization Of Multi-Functional Non-Spherical Particles Via Mechanical Deformation, Venkata Shilpa Varahagiri
Fabrication And Characterization Of Multi-Functional Non-Spherical Particles Via Mechanical Deformation, Venkata Shilpa Varahagiri
All Theses
Nanoparticles bridge the gap between bulk materials and molecules. They possess exciting but contrasting mechanical, chemical, magnetic and optical properties when compared to their bulk counterparts due to their shape and size. When the size of noble metal nanoparticles is reduced to less than the wavelength of light, the particles intensely absorb and scatter light at wavelengths that depend on the particle size, shape, and local dielectric environment due to Localized Surface Plasmon Resonance (LSPR) modes. Recently, plasmonic particles have been used in a wide variety of sensor and optical device applications including immunoassays and surface enhanced Raman spectroscopy substrates. …
Laminar Flame Speed Estimation From Experimental Data Using A Quasi-Dimensional Turbulent Flame Entrainment Combustion Simulation For Spark Ignition Engines, Akash Desai
All Theses
The goal of this research is to develop a thermodynamic simulation of spark-ignition engine combustion that uses a predictive burn-rate model. Previously done thermodynamic engine simulations in MATLAB are based on a specified burn rate model. Also, the effect of turbulence parameters on the rate of mass burn up is not considered. A predictive burn rate model is necessary to study the effect of different fuels on spark ignition engine combustion. The effect of laminar flame speed and turbulent intensity on combustion is difficult to assess experimental due to the difficulty in the measurement of these two variables. Thus, the …
Modeling Impacts Of Foothills Parkway Construction On Stream Water Quality Using Real-Time Remote Monitoring, Clark Chewning
Modeling Impacts Of Foothills Parkway Construction On Stream Water Quality Using Real-Time Remote Monitoring, Clark Chewning
All Theses
ABSTRACT
The need to monitor surface water quality has been increasingly recognized in recent years in environmental and natural resource management. The advent of real-time remote monitoring technologies has accelerated and enhanced this process. Field observations of water quality data are able to be conducted and analyzed in ways that were previously unavailable.
The objectives of this research were to deploy and test a real-time remote monitoring system for three small watersheds (Hembree, Dunn, and Rudd Hollows) in the Great Smoky Mountains. The watersheds ranged in size from 12 to 19 ha. Real-time remote monitoring stations were established in three …
A New Approach To Dynamic Modeling Of Continuum Robots, Nivedhitha Giri
A New Approach To Dynamic Modeling Of Continuum Robots, Nivedhitha Giri
All Theses
ABSTRACT
In this thesis, a new approach for developing practically realizable dynamic models for continuum robots is proposed. Based on the new dynamic models developed, a novel technique for analyzing the capabilities of continuum manipulators to be employed in various real world applications has also been proposed and developed.
A section of a continuum arm is modeled using lumped model elements (masses, springs and dampers). It is shown that this model, although an approximation to a continuum structure, can be used to conveniently analyze the dynamics of the arm with suitable tradeoff in accuracy of modeling. This relatively simple model …