Engineering Commons^™

Design, Manufacturing And Control Of An Advanced High-Precision Robotic System For Microsurgery, Arezoo Ebrahimi

Electronic Theses and Dissertations

Microsurgeries like ophthalmic surgery confront many challenges like limited workspace and hand motion, steady hand movements, manipulating delicate thin tissues, and holding the instrument in place for a long time. New developments in robotically-assisted surgery can highly benefits this field and facilitate those complicated surgeries. Robotic eye surgery can save time, reduce surgical complications and inspire more delicate surgical procedures that cannot be done currently by surgeon’s hands. In this thesis work, the requirements for ophthalmic surgeries were studied and based on that a robotic system with 6 DOF is proposed and designed. This robotic

system is capable of handling …

Exclusive-Or Preprocessing And Dictionary Coding Of Continuous-Tone Images., Takiyah K. Cooper

Electronic Theses and Dissertations

The field of lossless image compression studies the various ways to represent image data in the most compact and efficient manner possible that also allows the image to be reproduced without any loss. One of the most efficient strategies used in lossless compression is to introduce entropy reduction through decorrelation. This study focuses on using the exclusive-or logic operator in a decorrelation filter as the preprocessing phase of lossless image compression of continuous-tone images. The exclusive-or logic operator is simply and reversibly applied to continuous-tone images for the purpose of extracting differences between neighboring pixels. Implementation of the exclusive-or operator …

Synthesis And Functional Evaluation Of Peptide Modified Poly (Lactic-Co-Glycolic Acid) Nanoparticles To Inhibit Porphyromonas Gingivalis Biofilm Formation., Paridhi Kalia

Electronic Theses and Dissertations

Periodontal disease is an oral inflammatory disorder that afflicts roughly 46% of the adults in the U.S. Currently, treatment of periodontal disease involves the removal of plaque from the gingival pocket (with possible antibiotic treatment) and if necessary, gingival surgery. To our knowledge, no therapeutic approach exists that promotes host-biofilm homeostasis by limiting pathogen recolonization of the oral cavity after prophylaxis or treatment. The interaction of the pathogen Porphyromonas gingivalis with commensal streptococci is critical for initiation of periodontitis and represents a target for limiting P. gingivalis colonization of the oral cavity. Previous studies showed that a synthetic peptide …

Behavior Of Buried Composite Arch Bridges, Harold J. Walton

Electronic Theses and Dissertations

This dissertation presents experimental results and numerical analysis for short-span buried composite arch bridges whose main structural members are concrete-filled fiber reinforced polymer (FRP) tube arches (CFFTs). This investigation focuses on soil- structure interaction of the bridge system to expand understanding beyond isolated arch performance. Soil plays several roles: weight on the structure, restraining arch movement, and dissipating surficial truck loads.

Investigation focused on experimental and numerical analysis of subscale bridge systems. Four bridge systems were constructed with two different span-to-rise ratios (5:1 and 2.67:1) and two different materials (linear-elastic steel and CFFT). Tested systems were half-scaled from commercial bridge …

Spare Parts On Demand Using Additive Manufacturing : A Simulation Model For Cost Evaluation., Stefan Jedeck

Electronic Theses and Dissertations

Little is known about the impact of additive manufacturing in the spare part supply chain. A few studies are available, but they focus on specific parts and their applications only. A general model, which can be adapted to different applications, is nonexistent. This dissertation proposes a decision making framework that enables an interested practitioner/manager to decide whether using additive manufacturing to make spare parts on demand is economical when compared to conventional warehousing strategy. The framework consists of two major components: a general discrete event simulation model and a process of designing a wide range of simulation scenarios. The goal …

Novel Biomechanical Test Method For Cancellous Bone Screws And Screw Augmentation With Cement., Kevin Lancaster

Electronic Theses and Dissertations

It is often difficult to achieve adequate screw fixation for plate constructs in fractures with poor quality bone or in metaphyseal bone with extensive bone loss or comminution[7][17]. Furthermore, rescuing or augmenting failed screw fixation in inadequate bone with various cement products has yielded mixed results when tested with pure axial pullout loading[20][21]. In most cases, plate/screw constructs experience both vertical (translational) and horizontal (pullout) forces during physiologic loading[17][20][21]. The increased use of locked screws in plate constructs has also changed the loading patterns of bone screws. For this study, a novel “toggle-out” testing method was developed to more realistically …

New Visible Light Absorber For Solar Fuels : Ga(Sbx)N1-X Alloys., Swathi Sunkara

Electronic Theses and Dissertations

Solar energy conversion to fuels via photoelectrochemical water splitting is one of the most important technological directions toward meeting the global energy and environmental challenge. However, till date, there are no suitable semiconductor materials available that can absorb visible light, possess right kind of band edge energetics and are stable in aqueous environments. In this work, a new III-V alloy material Ga(Sbx)N1-x with dilute antimony concentration is proposed and developed for photoelectrochemical water splitting. Experimental studies were conducted first to synthesize the proposed alloy materials to understand structure-property relationships and compare them to those obtained using first principles computations. Finally, …

Evaluation Of Two-Phase Evaporation Pressure Drop Correlations For Low Refrigerant Mass Flux., Anna Fenko

Electronic Theses and Dissertations

This study was conducted to evaluate three currently popular two-phase pressure drop models for extremely low velocity refrigerant flow through smooth circular evaporators in household refrigeration systems. Experimental data was taken at mass fluxes under 70 kg/m²s for two refrigerants, R134A and R600A, internal diameters of aluminum evaporators ranging from 0.186 to 0.317 inches, U-bend internal radii ranging from 0.342 to 0.750 inches in horizontal and vertical orientations of evaporators. The geometry of the samples closely resembled a commonly used serpentine shape with multiple U-bends experiencing both, up- and down-flow of the refrigerant. Two empirical models, Müller-Steinhagen & …

Heat Transfer Mechanisms In Water-Based Nanofluids., Masoudeh Ahmadi

Electronic Theses and Dissertations

Nanofluids are a class of heat transport fluids created by suspending nano-scaled metallic or nonmetallic particles into a base fluid. Some experimental investigations have revealed that the nanofluids have remarkably higher thermal conductivities than those of conventional pure fluids and are more suited for practical application than the existing techniques of heat transfer enhancement using millimeter and/or micrometer-sized particles in fluids. Use of nanoparticles reduces pressure drop, system wear, and overall mass of the system leading to a reduction in costs over existing enhancement techniques. In this work, the heat transfer coefficient is determined experimentally using copper oxide (CuO) based …

Assessing The Water Quality Benefits Of Green Infrastructure Stormwater Control Measures., Sam Abdollahian

Electronic Theses and Dissertations

Permeable pavements systems and tree boxes are a common type of Green Infrastructure (GI) Stormwater Control Measures (SCMs) that are often used for mitigating the stormwater runoff. In this study two permeable pavement systems and a tree box installed along parking lanes of an urban street in Louisville, KY, were investigated to evaluate their performance on improving stormwater runoff quality. The water quality monitoring was accomplished by analysis of samples collected from stormwater runoff and the captured stormwater volume at the bottom of the permeable pavements’ sub-base reservoir and by a drain gauge (lysimeter) installed in the tree box. Pollutants …

Development Of A Vascularized, Induced Pluripotent Stem Cell-Derived Liver-Tissue Mimic For Therapeutic Applications., Venkat Madhav Ramakrishnan

Electronic Theses and Dissertations

This dissertation describes the incorporation of several technologies (stem cells, gene therapy, tissue engineering and regenerative medicine) into a single project that aims to produce a liver-tissue mimic for therapeutic applications. The liver is arguably one of the most complex organs in the body. In addition to its remarkable capacity to regenerate, it performs a host of vital functions. As a result, its impairment has widespread systemic consequences. The work described herein focused on the liver in the context of cardiovascular disease and used the heritable disorder Familial Hypercholesterolemia (FH) as a clinical disease model. As (a) the only definitive …

Application Of The Aeroacoustic Analogy To A Shrouded, Subsonic, Radial Fan., Bryan Buccieri

Electronic Theses and Dissertations

A study was conducted to investigate the predictive capability of computational aeroacoustics with respect to a shrouded, subsonic, radial fan. A three dimensional unsteady fluid dynamics simulation was conducted to produce aerodynamic data used as the acoustic source for an aeroacoustics simulation. Two acoustic models were developed: one modeling the forces on the rotating fan blades as a set of rotating dipoles located at the center of mass of each fan blade and one modeling the forces on the stationary fan shroud as a field of distributed stationary dipoles. Predicted acoustic response was compared to experimental data. The blade source …

Plasma Catalysis Using Low Melting Point Metals., Maria Carreon

Electronic Theses and Dissertations

Plasma catalysis is emerging as one of the most promising alternatives to carry out several reactions of great environmental importance, from the synthesis of nanomaterials to chemicals of great interest. However, the combined effect of a catalyst and plasma is not clear. For the particular case of 1-D nanomaterials growth, the low temperatures synthesis is still a challenge to overcome for its scalable manufacturing on flexible substrates and thin metal foils. Herein, the use of low-melting-point metal clusters under plasma excitation was investigated to determine the effectiveness in their ability to catalyze the growth of 1-D nanomaterials. Specifically, plasma catalysis …

Using Basic Quality Tools To Improve Production Yields And Product Quality In Manufacturing, Steve E. Black

Electronic Theses and Dissertations

As the U.S. and world economies emerge from years of recession, the hardwood flooring market is currently enjoying strong growth. With this growth come new challenges for hardwood flooring manufacturers. Strong competition from foreign markets and rising log prices are reducing product margins and forcing companies to think lean, while improving product quality.

QEP Wood Flooring division, who struggled through the worst of the U.S. economic down turn is now regaining ground as a strong competitor in the hardwood flooring market. This turnaround is due to internal changes to decrease waste and increase product quality. This is accomplished by using …

Solar Powered Picnic Table For Charging Cellphones And Other Small Devices, Casey B. Potts

Electronic Theses and Dissertations

Solar panels are used in many different applications for generating sustainable energy. Many countries use solar power as a power generation method. It is also, an excellent option for getting power to difficult areas. There are three main systems used when generating solar power: grid-tied, battery banked, and direct driven systems. Most systems use a combination of grid-tied and battery banked so any unused power can be fed back into the main grid for compensation. The solar power application suggested in this thesis will provide USB power to a picnic table enabling students to charge cellphones and other small devices …

Correlation Of Engineering Parameters Of The Presumpscot Formation To The Seismic Cone Penetration Test (Scptu), Mathew Hardison

Electronic Theses and Dissertations

The seismic cone penetration test with pore pressure measurement (SCPTu) is a geotechnical investigation technique which involves pushing a sensitized cone into the subsurface at a constant rate while continuously measuring tip resistance, sleeve friction, and pore pressure resulting from soil shearing. Additionally, shear wave velocity measurements can be collected at discrete intervals throughout the test. Empirical and theoretical correlations have been developed between these measurements and soil engineering properties such as preconsoldiation pressure and undrained shear strength. Soil classification, location of silt/sand seams, seismic design parameters, and liquefaction potential can also be obtained from SCPTu results.

The objective of …

The Role Of Al And Fe In Controlling Internal P Loading, Lake Auburn, Me, Heather Doolittle

Electronic Theses and Dissertations

Lake Auburn, Maine, U.S.A. is a historically oligotrophic lake serving as the primary drinking water source to a population of 40,000. In 2011 and 2012 the local water district observed decreasing water quality, evidenced by increasing epilimnetic total phosphorus (P) concentrations, increasing lake turbidity and the appearance of cyanobacteria. These conditions are especially concerning due to Lake Auburn’s exemption from filtration by the EPA. The decline in water quality has been linked to widespread hypolimnetic summer anoxia, causing internal P loading from the lake sediment. This study evaluated the chemical P speciation in hypolimnetic sediment from Lake Auburn following the …

Accelerating Scientific Computing Models Using Gpu Processing, Raymond F. Flagg Iii

Electronic Theses and Dissertations

GPGPUs offer significant computational power for programmers to leverage. This computational power is especially useful when utilized for accelerating scientific models. This thesis analyzes the utilization of GPGPU programming to accelerate scientific computing models.

First the construction of hardware for visualization and computation of scientific models is discussed. Several factors in the construction of the machines focus on the performance impacts related to scientific modeling.

Image processing is an embarrassingly parallel problem well suited for GPGPU acceleration. An image processing library was developed to show the processes of recognizing embarrassingly parallel problems and serves as an excellent example of converting …

Detailed Low-Cost Energy And Power Monitoring Of Computing Systems, Chad M. Paradis

Electronic Theses and Dissertations

Power and energy are increasingly important metrics in modern computing systems. Large supercomputers utilize millions of cores and can consume as much power as a small town; monitoring and reducing power consumption is an important task. At the other extreme, power usage of embedded and mobile devices is also critically important. Battery life is a key concern in such devices; having detailed power measurement allows optimizing these devices for power as well. Current systems are not set up to allow easy power measurement. There has been much work in this area, but obtaining power readings is often expensive, intrusive, and …

Microengineering The Neural Tube, Christopher Demers

Electronic Theses and Dissertations

Early embryonic development is a complex and highly regulated orchestra of instructive cues that collectively guide naïve stem cells towards progressively more specialized fates. In the neural tube, the precursor structure to the brain and spinal cord, these signals emanate from ‘organizing centers’ surrounding the neural tube. These organizing centers send out soluble cues or morphogens that diffuse tens to hundreds of microns to recipient cells residing in the neural tube. Re-creating this dynamic landscape of cues in vitro is impossible using standard cell culture tools and techniques. However, microfluidics is perfectly suited to fill this gap, allowing precise control …

Performing A Steady-State Seepage Analysis Using Seep/W : A Primer For Engineering Students., Matthew R. Broaddus

Electronic Theses and Dissertations

This thesis is comprised of five independent modules that were developed to provide a primer to understanding groundwater seepage. These modules serve as the template to conduct steady-state seepage analyses through embankments utilizing SEEP/W, a finite element seepage modeling program. Module 1 and 2 are more theoretical in nature to provide the background knowledge necessary to conduct a steady-state seepage analysis, while Modules 3, 4, and 5 focus more on the application of seepage models and how they can be used to solve various groundwater seepage problems. Supplementary material, including PowerPoint presentations, handouts, and a manual on how to utilize …

Synthesis, Optimization, And Degradation Of A Fish Glue/Plga Polymer., Adam T. Schworer 1989-

Electronic Theses and Dissertations

Biomaterials used for tissue engineering, specifically polymers, come from either naturally occurring, like gelatin or collagen, or synthetic sources, such as polyesters. Often times, it is advantageous to combine biomaterials in order to maximize certain material properties, such as cellular adhesion and degradation. The purpose of this study is to provide direction for the synthesis, characterization, and a combination of a combination biomaterial between fish glue (FG), a natural source polymer, and poly-lactic-co-glycolic acid (PLGA), a synthetically made polyester. First, FG is characterized for molecular weight via Gel Permeation Chromatography, GPC. Two combination methods to mix FG/PLGA solutions are then …

Geotechnical Laboratory Characterization Of Sand-Zeolite Mixtures., Hong Shang,

Electronic Theses and Dissertations

Zeolite and sand mixture is an ideal reactive filling material for the Permeable Reactive barrier (PRB) due to its higher hydraulic conductivity and sorption capacity. This study applied three ASTM standard tests to examine the geotechnical engineering properties of ASTM 20-30 sand and zeolite (clinoptilolite) mixtures with varying zeolite mass percentages (25%, 50%and 75%). Conducted lab tests including: Proctor compaction, hydraulic conductivity in rigid wall permeameter and one-dimensional consolidation. The goals of this study were to quantify the impact of zeolite content and compactive effort on the density, conduction and compressibility of the sand-zeolite mixtures.

Performance Analysis Of A Copper Ii Sulfate Pentahydrate Based Thermogalvanic Cell., Steffen Krebs

Electronic Theses and Dissertations

Low grade heat recovery systems are more relevant today due to the rising costs in energy and transition to non-fossil fuel energy sources. Thermogalvanic cells show potential due to low cost and scalability. In this study the performance of a Copper II Sulfate Pentahydrate based electrolyte was evaluated. The effects of electrolyte concentration, electrode separation, and electrode surface area were studied experimentally. Conductive heat transfer within the electrolyte was simulated via SolidWorks. All experimental thermocell testing was conducted to find the maximum power production of a particular cell design. The base cell had a six inch electrode separation with two …

Optimization Of Support Structures For Selective Laser Melting., Kai Zeng

Electronic Theses and Dissertations

Additive Manufacturing (AM) users rely on experiments and experience to predict the performance of AM processes. This trial and error approach for qualifying AM parts takes significant time and money. Simulation tools are an urgent need for today’s AM industry. One area of need is the automatic generation of optimized support structures based upon the scan patterns used to produce those structures. This research seeks to develop support structure generation tools based on real scan pattern and thermo-mechanical simulation tools for Selective Laser Melting (SLM) developed at the University of Louisville and being commercialized by 3DSIM, LLC. In order to …

Macro Model For Solid And Perforated Masonry Infill Shear Walls., Farid Nemati

Electronic Theses and Dissertations

In this dissertation the performance of masonry walls enclosed by frame structures is studied and a new finite element model for these systems is presented. As part of this effort, the common modeling approaches i.e. micro-models and macro-models are briefly reviewed and their specifications are compared. Based on the findings in these comparisons, it was shown that macro modeling is the preferred modeling approach and the development of the new model is presented. The proposed model is described in detail and the calibration procedures along with the material models, used in the proposed model, are presented. To account for the …

Mechanics Of Electrode Materials In Lithium Battery Applications., Jubin Chen

Electronic Theses and Dissertations

During lithiation and detlithiation, substantial volumetric changes occur within the electrode materials used for rechargeable lithium batteries. The magnitude of these deformations is inherently linked to the electrical capacity of the battery electrical capacity, which tends to degrade with repeated cycling. In this dissertation, the relationship between electrical discharge capacity and mechanical deformation state is examined using in-situ imaging of the working electrode surface within a custom CR2032 coin cell lithium battery. Digital image correlation is used to quantify electrode strains throughout the discharge-charge process. The effect of constraint due to substrate stiffness is investigated for two film materials: traditional …

Cost Effective Quality Assurance Practices In Highway Construction, James M. Newland

Electronic Theses and Dissertations

The estimated value of the U.S. transportation infrastructure is over $7.0 trillion. The challenge is preserving the quality of the investment. State and federal departments of transportation have methods and procedures for best quality, but vary significantly. With the variations comes opportunity to assess the cost-effectiveness of different strategies and make recommendation on practices that are most successful.

A survey was created and sent to all 50 states and the District of Columbia. The survey was aimed to capture information on construction finished product testing methods, optimized/reduced sampling techniques, innovative QA practices that measure multiple performance criteria and QA processes …

Model Of A Tubular Perfusion Bioreactor Using Computational Fluid Dynamics., Matthew James Robeson 1991-

Electronic Theses and Dissertations

Through recent years, many novel bioreactor designs for tissue engineering have emerged. The Tubular Perfusion System (TPS) is one such bioreactor for bone and cartilage tissue engineering. The TPS is a perfusion type bioreactor, in which media flows through a bed of scaffold beads. The advantage of this system over similar designs is that it requires no special fabrication techniques and operates at low pressure. Experimental trials have shown increased osteoblastic differentiation and mineralization of bone tissue grown using the TPS versus static culture. The effectiveness of the TPS in promoting osteoblastic differentiation is believed to be due to enhanced …

On The Viability Of Quantitative Assessment Methods In Software Engineering And Software Services, Joseph D. Lucente

Electronic Theses and Dissertations

IT help desk operations are expensive. Costs associated with IT operations present challenges to profit goals. Help desk managers need a way to plan staffing levels so that labor costs are minimized while problems are resolved efficiently. An incident prediction method is needed for planning staffing levels. The potential value of a solution to this problem is important to an IT service provider since software failures are inevitable and their timing is difficult to predict. In this research, a cost model for help desk operations is developed. The cost model relates predicted incidents to labor costs using real help desk …