Digital Commons Network^™

Development Of A Design Tool For Biologically Inspired Fault Adaptive Design By Strategy Mapping, Nicholas Steven Huisman

Graduate Theses and Dissertations

A design tool for Biologically Inspired Fault Adaption that utilizes the concept of strategy mapping was developed and the development process and testing is presented in this paper. The concept of strategy mapping is derived primarily from the field of military theory and supposes that for any given specific problem, that there exists a specific solution for, a single strategy can be identified for that solution/problem combination. This strategy, when applied to the specific problem yields the specific solution. This specific solution is referred to as the “tactics” of the strategy. The strategy can also be directly applied to a …

The Aerodynamic And Dynamic Loading Of A Slender Structure By An Impacting Tornado-Like Vortex: The Influence Of Relative Vortex-To-Structure Size On Structural Loading, Matthew Nicholas Strasser

Graduate Theses and Dissertations

Structural loading produced by an impacting vortex is a hazardous phenomenon that is encountered in numerous applications ranging from the destruction of residences by tornados to the chopping of tip vortices by rotors. Adequate design of structures to resist vortex-induced structural loading necessitates study of the phenomenon that control the structural loading produced by an impacting vortex. This body of work extends the current knowledge base of vortex-structure interaction by evaluating the influence of the relative vortex-to-structure size on the structural loading that the vortex produces. A computer model is utilized to directly simulate the two-dimensional impact of an impinging …

Development Of Pre-Stressed Cfrp Fatigue Retrofits For Common Steel Bridge Connections, Korey Albert Pough

Graduate Theses and Dissertations

Aging or deterioration of the nation’s bridge infrastructure is a significant issue that requires attention. Causes for much of this deterioration can be attributed to two main factors, 1) corrosion, and 2) metallic fatigue, both of which work together to reduce the strength and serviceability of bridge components over time. In many instances, strengthening of bridge components using localized retrofits offers an economical and fast solution for increasing the longevity of existing steel bridges; however, such retrofits must be resilient to further corrosion and fatigue damage. In this study, a localized retrofit is developed using pre-stressed Carbon Fiber Reinforced Polymer …

Investigation Of A Numerical Algorithm For A Discretized Rubber-Belt Continuously Variable Transmission Dynamic Model And Techniques For The Measurement Of Belt Material Properties., Brian Gene Ballew

Graduate Theses and Dissertations

A numerical algorithm for modeling the dynamic response of a rubber-belt Continuously Variable Transmission (CVT) belt is recreated. The numerical attributes applied to the algorithm and difficulties with numerical stability are discussed in detail. The degrees of freedom of the system have been expanded to include the dynamics of the engine torque output and vehicle loads such as rolling resistance and aerodynamic drag. This was done to emphasize the use of the model as an analysis tool for simulating CVT/engine/vehicle response. The increased degrees of freedom require the addition of a linear dampening element between belt nodes to dampen resonance …

Application Of Polyacrylamide-Based Floc Logs For Turbidity Control At Highway Construction Sites, Kien Ngo

Graduate Theses and Dissertations

Runoff waters generated on highway construction sites can have turbidities in excess of the proposed EPA regulatory standard of 280 NTU due to large areas of exposed soil. The objective of this research was to develop best management practices (BMPs) for the use of anionic polyacrylamide (PAM) based Floc Logs, for turbidity control. Five commercially available types of PAM-based Floc Logs were evaluated in jar tests, using soil excavated from Cato Springs Research Center (CSRC, Fayetteville AR) and six types of clay from the Clay Minerals Society (Chantilly, VA). These results show that no single Floc Log type was suitable …

Investigation Of The Inherent Chemical, Structural, And Mechanical Attributes Of Bio-Engineered Composites Found In Nature: Alligator Gar’S Exoskeleton Fish Scales, Wayne Derald Hodo

Graduate Theses and Dissertations

The U.S. Army has determined a huge cost savings of up to 51% can be accomplished by reducing the gross vehicle weight, for their personnel carrier, by 33%. To cut cost, composite materials are needed. Man-made composites can have superior material properties (high-strength, high-fracture toughness, and lightweight), but they are prone to delamination at the glued-layered interface. In contrast, fish scale is a natural composite that has the same material properties and, additionally, tend not to delaminate.

The focus of this study was to learn how nature integrates hard and soft materials at each length scale to form a layered …

Storage Of Round And Square Switchgrass Bales: Effect Of Storage Time And Fungal Inoculation On Saccharification Efficiency, Noaa Frederick

Graduate Theses and Dissertations

To produce fermentable sugars from lignocellulosic biomass feedstock, severe pretreatment conditions are needed (either high acid concentration, temperature, or retention times). High severities can produce toxic byproducts which inhibit enzymatic hydrolysis or fermentation. In order to reduce pretreatment severities (and thus increase enzyme and fermentation efficiency), the white-rot fungus Pleurotus ostreastus was seeded into square and round bales of Kanlow switchgrass (Panicum virgastum L.) and left in the field over a period of 9 month. The laccase producing fungus is believed to selectively degrade lignin, a common plant structural polymer, which can function as an enzymatic inhibitor. Samples were taken …

Design Of Elastic Metamaterials, Yu-Chi Su

Open Access Dissertations

This study focused on the design and fabrication of a double negativity and three broadband single negativity elastic metamaterials using a 3D printer. We investigated dispersion curves and dynamic material properties of the metamaterials. Negative phase velocity in the double negativity metamaterial was also demonstrated.

For metamaterials with single negativity, three types of broadband metamaterials were designed from parametric studies. A comparison showed that using frame bending/stretching mode is more effective than applying beam bending mode to broaden bandgap. Furthermore, it is found that adding internal resonant components could enlarge the bandgap. The single negativity metamaterials were validated by numerical …

Generalized Techniques For Using System Execution Traces To Support Software Performance Analysis, Thelge Manjula Peiris

Open Access Dissertations

This dissertation proposes generalized techniques to support software performance analysis using system execution traces in the absence of software development artifacts such as source code. The proposed techniques do not require modifications to the source code, or to the software binaries, for the purpose of software analysis (non-intrusive). The proposed techniques are also not tightly coupled to the architecture specific details of the system being analyzed. This dissertation extends the current techniques of using system execution traces to evaluate software performance properties, such as response times, service times. The dissertation also proposes a novel technique to auto-construct a dataflow model …

Estimating The Water Quality Condition Of River And Lake Water In The Midwestern United States From Its Spectral Characteristics, Jing Tan

Open Access Dissertations

This study focuses on developing/calibrating remote sensing algorithms for water quality retrieval in Midwestern rivers and lakes. In the first part of this study, the spectral measurements collected using a hand-held spectrometer as well as water quality observations for the Wabash River and its tributary the Tippecanoe River in Indiana were used to develop empirical models for the retrieval of chlorophyll (chl) and total suspended solids (TSS). A method for removing sky and sun glint from field spectra for turbid inland waters was developed and tested. Empirical models were then developed using a subset of the field measurements with the …

Eicosapentaenoic Acid (Epa) From Porphyridium Cruentum: Increasing Growth And Productivity Of The Microalgae For Pharmaceutical Products, Maryam Asgharpour

Graduate Theses and Dissertations

One of the major nutritional requirements in our diet is an adequate intake of omega-3 specially eicosapentaenoic acid (EPA). In the present study, the effects of two temperatures (16°C & 20˚C) and light intensities (140 & 180µE/M2.S) and four nitrate levels (0.075, 0.3, 0.5 and 0.7g/L) on the cell growth and lipid productivity of Porphyridium cruentum, one of the most promising oil-rich species of microalgae, were investigated. A growth comparison was carried out using pure CO2 and 5% CO2/air. Additionally, the ratio of the fatty acids with omega-3 and omega-6 groups at various growth conditions were compared, since an appropriate …

Modulation Of Valve Interstitial Cell Function Through Cell Shape And Phenotype, Atefeh Razavi

Graduate Theses and Dissertations

The aortic valve is a highly dynamic structure responding to actively to the chemical, mechanical and physical cues of the valve microenvironment. Valve interstitial cells are dispersed throughout the valve tissue and play an important role in maintaining the integrity and optimum function of the valve. They are a heterogeneous population composed of various phenotype. These phenotypes have specific functions characteristic of valve physiological and pathological conditions. The effect of mechanical loading and chemical modulators on the behavior of the valve interstitial cells have largely been studied. However the role of valve interstitial cell shape as an intrinsic physical cue …

Swat Model Simulation Of Bioenergy Crop Impacts On Water Quality In Cache River Watershed, Eeshan Kumar

Graduate Theses and Dissertations

Energy security through increased biofuel production is one of the components of the Energy Independence and Security Act (EISA) 2007. As per EISA 2007 mandate, appropriate independent research institutes are required to assess concerns to natural biodiversity due to biofuel production and report it to the Congress through the Environment Protection Agency (EPA). Planners, researchers, and agencies concerned with environmental regulations, ideally, would like to have location-specific information about the impacts for developing appropriate management interventions. This study examines long-term impacts on water quality in response to targeted (i.e. marginal lands) production of biofuel crops by setting up two SWAT …

Image Processing And Visualization Of Terahertz Pulsed Imaging Of Breast Cancer Tumors, Yuhao Wu

Graduate Theses and Dissertations

Terahertz imaging technology has grown substantially in recent years. With new advances made in the generation, manipulation, and detection of terahertz radiation, terahertz imaging has found its application as inspection tools in a wide range of areas including biomedicine, materials science, and aerospace industries. In the field of medical imaging, terahertz (THz) has emerged as a new imaging modality due to some fundamental physical properties of the THz wave. THz imaging has been used to examine various biological structures, and THz tomography has been developed to probe the 3D structures of those samples.

THz pulsed imaging (TPI) is one of …

Evaluation Of Conservation Practices Through Simulation Modeling And Tool Development, Gurdeep Singh

Graduate Theses and Dissertations

For the first objective, predicted impacts of selected Mississippi River Basin Initiative (MRBI) conservation practices (CPs) on sediment and nutrient loss were assessed. The study area was L’Anguille River Watershed (LRW), a priority focus watershed of the MRBI program and the simulated CPs were filter strip, critical area planting, grade stabilization structure, irrigation land leveling, irrigation pipeline, irrigation water management, and nutrient management. The Soil and Water Assessment Tool (SWAT) model was calibrated (1998 – 2005) and validated (2006 – 2012) for flow, sediment, total phosphorus (TP), and nitrate-nitrogen (NO3-N) at the Colt site (503 sq. km. drainage area) and …

Design And Development Of A Wearable Wireless Health Monitoring System: A Smart Watch Approach, Keerthi Paranikumar

Graduate Theses and Dissertations

According to Statistics, every year, about 610,000 people die because of heart disease in United States of America. (i.e. 1 in every 4 deaths.*) Heart disease is common for both men and women. Annually, about 370,000 people die because of coronary heart disease, which is the most common type of heart disease [1]. About 735,000 Americans have heart attack every year. In this, 210,000 people gets heart attack who already has heart problems and 525,000 people get heart attack for the first time [2]. Not many people know that they have heart problems. Around 47% of the people in United …

Epitaxial Growth Of Si-Ge-Sn Alloys For Optoelectronic Device Application, Aboozar Mosleh

Graduate Theses and Dissertations

Microelectronics industry has experienced a tremendous change over the last few decades and has shown that Moore’s law has been followed by doubling the number of transistors on the chip every 18 months. However, continuous scaling down of the transistors size is reaching the physical limits and data transfer through metal interconnects will not be able to catch up with the increasing data processing speed in the future. Therefore, optical data transfer between chips and on-chip has been widely investigated. Silicon based optoelectronics has received phenomenal attention since Si has been the core material on which microelectronic industry has been …

Model Development And Validation For Wind Generation Transmission Systems, Mahmood Shihadeh Saadeh

Graduate Theses and Dissertations

In this research a new benchmark system is proposed for wind energy transmission systems. New model development, validation, and calibration methods for power transmission systems are proposed and implemented as well. First, a model reduction criteria is chosen based on electrical interconnection and geographical information. Model development is then done using reduction techniques on an operation model provided by a transmission operator based on the chosen criteria. Then model validation is performed using actual PMU synchrophasor measurements provided by a utility company. The model development and validation process ensures the accuracy of the developed model and makes for a realistic …

Field Amplified Sample Stacking On Amyloid Beta (1-42) Oligomers Using Capillary Electrophoresis, Sadia Ali Paracha

Graduate Theses and Dissertations

According to recent literature, it is believed that the oligomeric form of amyloid beta (Aβ) is the leading cause of Alzheimer’s disease (1; 8; 10; 12-18). Additionally, recent studies have eluded to the impact of Alzheimer’s disease (AD) both economically and Socially in today’s society where an increase of about 71% of AD related deaths were recorded between 2000 and 2013 (7). Since the oligomeric forms of Aβ vary in size, shape and some believe conformation, it is vital to utilize a separation technique, such as capilllary electrophoresis (CE) to further understand Aβ aggregation. By understanding Aβ aggregation, treatment of …

Effects Of Magnetically Induced Micro-Mixing On Nanofiltration Performance, Guanghui Song

Graduate Theses and Dissertations

Nanofiltration (NF) is a relatively new membrane separation process mainly used for removing low molecular weight species from aqueous and non-aqueous solutions. NF membranes suffer from concentration polarization leading to membrane fouling thus compromised membrane performance. Magnetically responsive nanofiltration (NF) membranes functionalized with superparamagnetic nanoparticles (SPNs) attached to the chain ends of grafted polymer nanolayers have been shown to be effective in breaking concentration polarization at the membrane-liquid interface under an appropriate external oscillating magnetic field. Under an oscillating magnetic field, the movement of the polymer chains acts as micro-mixer leading to the suppression of concentration polarization and improved filtration …

Compounds Released From Biomass Deconstruction: Understanding Their Effect On Cellulose Enzyme Hydrolysis And Their Biological Activity, Angele Djioleu

Graduate Theses and Dissertations

The effect of compounds produced during biomass pretreatment on cellulolytic enzyme was investigated. Liquid prehydrolyzates were prepared by pretreating switchgrass using 24 combinations of temperature, time, and sulfuric acid concentration based on a full factorial design. Temperature was varied from 140°C to 180°C; time ranged from 10 to 40 min; and the sulfuric acid concentrations were 0.5% or 1% (v/v). Identified products in the prehydrolyzates included xylose, glucose, hydroxymethylfurfural (HMF), furfural, acetic acid, formic acid, and phenolic compounds at concentration ranging from 0 to 21.4 g/L. Pretreatment conditions significantly affected the concentrations of compounds detected in prehydrolyzates. When assayed in …

Modified Polysulfone Nanofiltration Membrane Synthesis For Hydraulic Fracturing Water Recycle, Blake Alexander Johnson

Graduate Theses and Dissertations

The use of hydraulic fracturing has resulted in significant increases in the yield of oil and natural gas, as water pumped into wells at high pressure cracks the formations and releases the hydrocarbons that are locked in the rocks. This process has created large volumes of brackish water that is very difficult to process and is often disposed of into injection wells. Suspended solids and some dissolved solids are more readily removed, but the multivalent ions found in certain salts can precipitate in a well and complicate the reuse of flowback in future hydraulic fracturing operations.

Nanofiltration, a membrane separation …

Production Of Ethanol From Cereal Food Fines Using Dilute-Acid Hydrolysis, Andrew Edward Arnett

Graduate Theses and Dissertations

Cereal food fines are a leftover by-product from breakfast cereal processing that is typically sold as animal feed or used as a pet food ingredient; however this product could be of greater value as a feedstock for the production of fuel ethanol via fermentation. In order for this material to be fermented it has to be broken down in to simple sugars using hydrolysis. One method of hydrolysis is called dilute-acid hydrolysis, whereby low concentrations of acid are added to the feedstock to facilitate the breaking of chemical bonds. This study investigates the effect of different concentrations of acid to …

Wireless Monitoring Of Driver's Pulse Rate And Temperature Using Hand Gloves Approach, Rohith Reddy Narala

Graduate Theses and Dissertations

There is growing concern about dangers correlated with driving, for people with known cardiovascular diseases. However, the association between having a chronic cardiovascular disease and being involved in a motor vehicle crash remains controversial. This study aims to monitor people with known medical emergencies or other medical conditions while driving [1]. It also helps the co-passengers to be cautious while the person is driving with an abnormal health condition. Designed it to be convenient and also can be easily adaptable by the end user.

The proposed project focuses on a wearable sensor glove that equipped with a pulse rate sensor, …

High-Frequency Transformer Design For Solid-State Transformers In Electric Power Distribution Systems, Roderick Javier Garcia Montoya

Graduate Theses and Dissertations

The objective of this thesis is to present a high- or medium-frequency transformer design methodology for Solid-State Transformer (SST) applications. SSTs have been proposed as a replacement of the traditional 50/60 Hz transformer in applications demanding high-power density. Moreover, due to the high penetration of distributed generation, DC grids, energy storage systems, and sensitive loads, SSTs have been considered as an enabling technology for envisioned future energy systems. These applications demand additional functionalities that may not be achieved with traditional transformers. For example, active power flow control, harmonic suppression, voltage regulation, voltage sag compensation, and reduced size and volume.

In …

A Handcrafted Multi-Branch Nerve Scaffold For In Vivo Peripheral Nerve Regeneration, Ridwan Fayaz Hossain

Theses and Dissertations

Arm and leg peripheral nerve injuries contribute largely to functional disability. These injuries seldom affect a single-line nerve; rather the injury goes beyond and disrupts the nerve tissue across multiple nerve paths. Here we investigate handcrafted PDMS based multi-branch nerve guidance conduit, which addresses this crucial branching from the sciatic nerve to aid with the regeneration to their appropriate distal targets. The design concept of the developed multiple branch nerve scaffolds is not specific for the sciatic nerve but can be modified for general use of all peripheral nerves and additional applications. Microchannels are also fabricated into a device in …

Pressure Field Estimation Using Particle Image Velocimetry, Jean O. Calzada

Theses and Dissertations

In recent years, scientist and engineers have shown the advantages created by using the Particle Image Velocimetry (PIV) method as flow diagnostic tool to characterize instantaneous velocity fields. One of the important benefits is found on its non-intrusive nature, this leads to accurate velocity fields. From the velocity field obtained by PIV important quantities can be derived, such as pressure and vorticity. The present study, uses PIV data of an incompressible turbulent pulsed jet to determine the pressure field associated with the flow field. The pressure is calculated by using the averaged velocity field along with three different fundamental equation: …

Modeling The Residual Useful Life Of Railroad Bearing Grease, Thania Alejandra Martinez

Theses and Dissertations

Railroad bearing performance is often constrained by the life of its lubricant. The lubricant life is determined by tribomechanical processes that are present during bearing operation. No known physical models exist to predict the railroad bearing lubricant life. This thesis summarizes the efforts undertaken in the development of empirical models that can accurately predict the residual useful life of railroad bearing grease. Modeling techniques to be employed include regression, regression trees, and split plots. The grease samples used to populate this model come from healthy and faulty bearings that were run under different loads, speeds, and ambient conditions in a …

Natural Polymer Based Composite Scaffolds For Tissue Engineering Applications, Marcos R. Villarreal

Theses and Dissertations - UTB/UTPA

The fabrication, characterization, and bio-assessment of two types of perspective tissue engineering (TE) scaffolds are presented. Principally derived of biopolymers, both types of scaffolds generally followed porous scaffold methodologies for synthesis. Differentiating the two scaffold varieties was chiefly driven by crosslinking attainment, where crosslinking is argued to add structural stability and aid in regulating biodegradability rates in TE scaffolds. Microwave irradiation via conventional microwave was one method used to prospectively crosslink cornstarch to chitosan and sodium alginate. Triethyl orthoformate, was used to prospectively crosslink collagen and chitosan. After the scaffolds were “crosslinked” they were subjected to freeze drying techniques in …

Two-Dimensional Dynamics Model Of The Lower Limb To Include Viscoelastic Knee Ligaments, Eduardo Granados

Theses and Dissertations - UTB/UTPA

A dynamic, 2D, anatomical knee joint model has been developed to simulate knee reactions to external input forces. A deformable contact area approach is used to find contact forces and moments, and a method of applying nonlinear viscoelastic ligament strain rate response was also developed and implemented on the model to account for the effects of viscoelasticity on the ligament fibers. The ligaments were then tested for various deficiencies to identify their effects on the natural frequency of the knee. Internal knee forces from ligaments, muscles, and contacting surfaces are modeled and then numerically found for different exercises. Static and …