Engineering Commons^™

2d Modeling Of Forcespinning™ Nanofiber Formation With Experimental Study And Validation, Simon Padron

Theses and Dissertations - UTB/UTPA

A newly developed method of producing nanofibers, called Forcespinning™, has proven to be a viable alternative to mass produce nanofibers. Forcespinning™ utilizes centrifugal forces which allow for a host of new materials to be processed into nanofibers while also providing a significant increase in yield and ease of production. To improve and enhance the Forcespinning™ production method, a 2D computational Forcespinning™ fluid dynamics model is developed. Three computer models, namely time-independent and time-dependent inviscid models and a viscous model are obtained and the influences of various parameters on Forcespinning™ fiber formation are obtained. This work also presents a detailed explanation …

Electromagnetic Interference Shielding Effectiveness Of Metallic Thin Films Deposited On High Density Polyethylene And Styrene Butadiene Copolymer Reinforced With Carbon Nanofibers, Horus Garcia

Theses and Dissertations - UTB/UTPA

Aluminum, Copper and Silver were deposited by thermal evaporation onto Vapor Grown Carbon Nanofiber (VGCNF) reinforced High Density Polyethylene (HDPE) and Styrene Butadiene Copolymer (SBC) composites. Electromagnetic Interference Shielding Effectiveness (EMI SE) was conducted on the structures to analyze the synergistic effect. Characterization was performed by Scanning Electron Microscopy, X-ray Diffraction, and Atomic Force Microscopy. Adhesion test and surface influence on SE were also performed. It was observed that a single layer metallic thin film on carbon nanofiber (CNF) polymer composite experienced a summation of shielding performance. The EMI SE increased with CNF content increase of 10, 15, and 20 …

Measuring Merci: Exploring Data Mining Techniques For Examining Surgical Outcomes Of Stroke Patients, Matthew Ronald Mcnabb

Masters Theses and Doctoral Dissertations

Mechanical Embolus Removal in Cerebral Ischemia (MERCI) has been supported by medical trials as an improved method of treating ischemic stroke past the safe window of time for administering clot-busting drugs, and was released for medical use in 2004. The importance of analyzing real-world data collected from MERCI clinical trials is key to providing insights on the effectiveness of MERCI. Most of the existing data analysis on MERCI results has thus far employed conventional statistical analysis techniques. To the best of the knowledge acquired in preliminary research, advanced data analytics and data mining techniques have not yet been systematically applied. …

Determining The Operation Limits Of Two Distillation Columns, Murat Ozkaya

Masters Theses and Doctoral Dissertations

The two distillation columns of Wacker Institute pilot plant at the Chattanooga State Community College are investigated for stable operating regions, flooding phenomena that occurs in the bubble-cap tray distillation column, weeping phenomena that occurs in the sieve tray distillation column, and comparison of operation between the two distillation columns. With the use of a distributed control system (DCS) and glass equipment in the pilot plant, these phenomena are analyzed visually and with the help of instrumentation readings. The energy usage and production limits of both distillation columns are discussed. The flooding of bubble-cap trays occur before reaching production goals …

Architecture And Method For Providing Priority Charging For Government Authorized Emergency Electrical Vehicles (Aeev), Naga Durga Praveen Vemulapalli

Masters Theses and Doctoral Dissertations

The US government predicts more than 1 million electric vehicles (EVs), on U.S. roadways by 2015, and these numbers will increase exponentially in the future. However, the power grid cannot furnish the charging for numerous EVs at a given time mainly because of its energy production capabilities, peak usage, and distribution infrastructure. Some studies indicate that adopting “smart” charging, for example, scheduling EV charging, can alleviate the challenge. Nevertheless, such strategies are not useful for emergency and first responders’ vehicles. This thesis proposes a solution that provides priority treatment for government Authorized Emergency Electrical Vehicles (AEEV). The thesis proposes a …

Mesh Generation Using A Correspondence Distance Field, Nicholas Szapiro

Masters Theses and Doctoral Dissertations

The central tool of this work is a correspondence distance field to discrete surface points embedded within a quadtree data structure. The theory, development, and implementation of the distance field tool are described, and two main applications to two-dimensional mesh generation are presented with extension to three-dimensional capabilities in mind. First is a method for surface-oriented mesh generation from a sufficiently dense set of discrete surface points without connectivity information. Contour levels of distance from the body are specified and correspondences oriented normally to the contours are created. Regions of merging fronts inside and between objects are detected in the …

Tribiology Of Engineered Surfaces In Aggressive Environments, Nathan Phillip Mitchell

All Theses

To improve the performance of sliding systems, surface modifications and coatings are often applied to opposing surfaces. This thesis focuses on characterizing two tribo-systems (DLC-DLC and steel micropatterns-flat) under their predicted application environments. The first section is focused on friction testing of micropatterned surfaces for orthopaedic device design, the second section elucidates how the sliding of diamond-like-carbon (DLC) coatings changes with temperature and humidity. The experimental design and major results of these sections are as follows.

(1) The use of micropatterning to create uniform surface morphologies has been cited as yielding improvements in the coefficient of friction during high velocity …

Operational Guidance For Bicycle-Specific Traffic Signals In The United States, Christopher Monsere, Miguel A. Figliozzi, Sam Thompson, Kirk Paulsen

Civil and Environmental Engineering Faculty Publications and Presentations

The research consisted of two phases: 1) a synthesis of practice and 2) and analysis of cyclist performance characteristics. The synthesis of current practice reviewed the literature, current engineering design and operational guidance documents, and surveyed the jurisdictions about their current deployments of bicyclespecific signals. This report summarizes research of cyclist behavior at signalized intersections in Portland, Eugene, Corvallis, Beaverton and Clackamas County, OR. These signals had both bicycle-specific indications and vehicle-only signals. A total of 4,673cyclists were observed. For each cyclist observed arriving on red, a set of descriptive variables were collected (e.g., age, sex, helmet use, presence of …

Improving Complementary Methods To Predict Evapotranspiration For Data Deficit Conditions And Global Applications Under Climate Change, Fathi M. A. Anayah

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A reliable estimate of evapotranspiration (ET) in river basins is important for the purpose of water resources planning and management. ET represents a significant portion of rainfall in the water budget; therefore, the uncertainty in estimating ET can lead to the inaccurate prediction of water resources. While remote sensing techniques are available to estimate ET, such methods are expensive and necessary data may not be readily available. Classical methods of estimating ET require detailed land use/cover information that are not readily available in rural river basins. Complementary methods provide simple and reliable approaches to estimate ET using meteorological data only. …

The Antimycobacterial Activity Of Hypericum Perforatum Herb And The Effects Of Surfactants, Shujie Shen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Tuberculosis is a stubborn and lethal infectious disease. The world-wide tuberculosis surveillance reports that the new TB cases ranges from seven to eight million per year and deaths ranges from 1.3 to 1.6 million every year. The treatment of tuberculosis mainly depends on antituberculosis drugs, such as isoniazid, rifampin, pyrazinamide and ethambutol. However, drug-resistance acquisition is an inevitable process during tuberculosis treatment. Today, multi-drug resistant and the extensively drug-resistant TB cases have been widely reported around the world. Thus, the discovery of novel antituberculosis drugs is essential to effective TB treatment. Hypericum perforatum, also called St. John’s Wort, is …

Compressive Point Cloud Super Resolution, Cody S. Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Automatic target recognition (ATR) is the ability for a computer to discriminate between different objects in a scene. ATR is often performed on point cloud data from a sensor known as a Ladar. Increasing the resolution of this point cloud in order to get a more clear view of the object in a scene would be of significant interest in an ATR application.

A technique to increase the resolution of a scene is known as super resolution. This technique requires many low resolution images that can be combined together. In recent years, however, it has become possible to perform super …

The Patrol Scheduling Problem, Hoong Chuin Lau, Aldy Gunawan

Research Collection School Of Computing and Information Systems

This paper presents the problem of scheduling security teams to patrol a mass rapid transit rail network of a large urban city. The main objective of patrol scheduling is to deploy security teams to stations at varying time periods of the network subject to rostering as well as security-related constraints. We present a mathematical programming model for this problem. We then discuss the aspect of injecting randomness by varying the start times, the break times for each team as well as the number of visits required for each station according to their reported vulnerability. Finally, we present results for the …

Uncertain Congestion Games With Assorted Human Agent Populations, Asrar Ahmed, Pradeep Reddy Varakantham, Shih-Fen Cheng

Research Collection School Of Computing and Information Systems

Congestion games model a wide variety of real-world resource congestion problems, such as selfish network routing, traffic route guidance in congested areas, taxi fleet optimization and crowd movement in busy areas. However, existing research in congestion games assumes: (a) deterministic movement of agents between resources; and (b) perfect rationality (i.e. maximizing their own expected value) of all agents. Such assumptions are not reasonable in dynamic domains where decision support has to be provided to humans. For instance, in optimizing the performance of a taxi fleet serving a city, movement of taxis can be involuntary or nondeterministic (decided by the specific …

Dynamic Stochastic Orienteering Problems For Risk-Aware Applications, Hoong Chuin Lau, William Yeoh, Pradeep Varakantham, Duc Thien Nguyen

Research Collection School Of Computing and Information Systems

Orienteering problems (OPs) are a variant of the well-known prize-collecting traveling salesman problem, where the salesman needs to choose a subset of cities to visit within a given deadline. OPs and their extensions with stochastic travel times (SOPs) have been used to model vehicle routing problems and tourist trip design problems. However, they suffer from two limitations travel times between cities are assumed to be time independent and the route provided is independent of the risk preference (with respect to violating the deadline) of the user. To address these issues, we make the following contributions: We introduce (1) a dynamic …

Toward Large-Scale Agent Guidance In An Urban Taxi Service, Agussurja Lucas, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

Empty taxi cruising represents a wastage of resources in the context of urban taxi services. In this work, we seek to minimize such wastage. An analysis of a large trace of taxi operations reveals that the services’ inefficiency is caused by drivers’ greedy cruising behavior. We model the existing system as a continuous time Markov chain. To address the problem, we propose that each taxi be equipped with an intelligent agent that will guide the driver when cruising for passengers. Then, drawing from AI literature on multiagent planning, we explore two possible ways to compute such guidance. The first formulation …

Bidder Behaviors In Repeated B2b Procurement Auctions, Jong Han Park, Jae Kyu Lee, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

B2B auctions play a key role in a firm's procurement process. Even though it is known that repetition is a key characteristic of procurement auctions, traditional auctioneers typically have not put in place a suitable mechanism that supports repetitive auctions effectively. In this paper, we empirically investigate what has taken place in repeated procurement auctions based on real world data from a major outsourcing company of MRO (Maintenance, Repair and Operations) items in Korea. From this empirical study, we discovered the followings. First, we discovered that the repeated bidders contribute majority of all bids, and that the number of new …

Measurement Of The Oxidation State Of Mitochondrial Cytochrome C From The Neocortex Of The Mammalian Brain, Y. Sakata, M. Abajian, M. O. Ripple, R. Springett

Dartmouth Scholarship

Diffuse optical remission spectra from the mammalian neocortex at visible wavelengths contain spectral features originating from the mitochondria. A new algorithm is presented, based on analytically relating the first differential of the attenuation spectrum to the first differential of the chromophore spectra, that can separate and calculate the oxidation state of cytochrome c as well as the absolute concentration and saturation of hemoglobin. The algorithm is validated in phantoms and then tested on the neocortex of the rat during an anoxic challenge. Implementation of the algorithm will provide detailed information of mitochondrial oxygenation and mitochondrial function in physiological studies of …

Component Mode Synthesis Approach For Quantum Mechanical Electrostatic And Transport Analysis Of Nanoscale Structures And Devices, Zhe Gao

All Theses

As the dimensions of commonly used semiconductor devices have shrunk into nanometer regime, it is recognized that the influence of quantum effects on their electrostatic and transport properties cannot be ignored. In the past few decades, various computational models and approaches have been developed to analyze these properties in nanostructures and devices. Among these computational models, the Schršdinger-Poisson model has been widely adopted for quantum mechanical electrostatic and transport analysis of nanostructures and devices such as quantum wires, metal-oxide-semiconductor field effect transistors (MOSFETs) and nanoelectromechanical systems (NEMS). The numerical results allow for evaluations of the electrical properties such as charge …

Investigation Of Prototype Roles In Conceptual Design Using Case Study And Protocol Study Methods, Timothy Hess

All Theses

Prototypes play an important role in the engineering design process. Engineering design textbooks often discourage the use of prototypes early in the design process, citing past research on prototypes in engineering design has focused describing and classifying the prototypes themselves. The gap in this research is the investigation of prototyping processes. While researchers have studied the characteristics of different prototypes and in some cases have tried to tie characteristics to the outcomes of the design process, the actual prototyping activities and the process of building and using the prototypes has not been studied in detail. The work presented in this …

Socialq&A: A Novel Approach To Notifiying The Correct Users In Question And Answering Systems, Nikhil Vithlani

All Theses

Question and Answering (Q&A) systems are currently in use by a large
number of Internet users. Q&A systems play a vital role in our daily life as
an important platform for information and knowledge sharing. Hence, much
research has been devoted to improving the performance of Q&A systems,
with a focus on improving the quality of answers provided by users, reducing
the wait time for users who ask questions, using a knowledge base to provide
answers via text mining, and directing questions to appropriate users. Due
to the growing popularity of Q&A systems, the number of questions in the
system …

Enzyme Actuated Bioresponsive Hydrogels, Andrew Wilson

All Theses

Bioresponsive hydrogels are emerging with technological significance in targeted drug delivery, biosensors and regenerative medicine. Conferred with the ability to respond to specific biologically derived stimuli, the design challenge is in effectively linking the conferred biospecificity with an engineered response tailored to the needs of a particular application. Moreover, the fundamental phenomena governing the response must support an appropriate dynamic range and limit of detection. The design of these systems is inherently complicated due to the high interdependency of the governing phenomena that guide the sensing, transduction, and the actuation response of hydrogels. To investigate the dynamics of these materials, …

Stabilization Of Extracellular Matrix Components In Bioprosthetic Heart Valves Using Neomycin And Pentagalloyl Glucose Enhanced Crosslinking, Daniel Tripi

All Theses

Bioprosthetic heart valves (BHVs) fail within 12-15 years of implantation due to limited durability. This limits their application to elderly population. Younger patients with contraindications for long-term anticoagulant therapy necessary for mechanical heart valves may also receive BHVs. Investigation into improving valve durability can lead to longer implant life, increased quality of life for patients receiving BHVs, and a broadened patient demographic.
Current BHVs are chemically treated with glutaraldehyde (GLUT) to stabilize collagen via chemical crosslinking and to reduce tissue antigenicity. GLUT fails to adequately stabilize elastin and glycosaminoglycans (GAGs), essential extracellular matrix components for valve function and durability. Degradation …

Continuum Limbed Robots For Locomotion, Alper Mutlu

All Theses

This thesis focuses on continuum robots based on pneumatic muscle technology. We introduce a novel approach to use these muscles as limbs of lightweight legged robots. The flexibility of the continuum legs of these robots offers the potential to perform some duties that are not possible with classical rigid-link robots. Potential applications are as space robots in low gravity, and as cave explorer robots.
The thesis covers the fabrication process of continuum pneumatic muscles and limbs. It also provides some new experimental data on this technology. Afterwards, the designs of two different novel continuum robots - one tripod, one quadruped …

Development And Characterization Of Shellac-Hydroxypropyl Methyl Cellulose Composite Films With Acid Catalyst, Sana Asrar

All Theses

The objective of this research was to develop a shellac-hydroproyl methyl cellulose (Sh-HPMC) composite film with enhanced water vapor barrier. Citric acid (CA) was used as an acid catalyst, to promote miscibility between HPMC and shellac. In a preliminary test, three different concentrations of CA (1000:1, 200:1, 100:1) were tested to identify the best Sh:CA ratio. Based on the Water vapor permeability properties and mechanical properties, Sh-CA (1000:1 ratio) had the most enhanced water vapor barrier and the lowest reduction in tensile strength compared to the pure HPMC film (control). In the later part of the research, the effect of …

Evaluation Of Dichloromethane As An Electron Donor For Reductive Dechlorination Of Tetrachloroethene To Ethene, Yogendra Kanitkar

All Theses

Tetrachloroethene (PCE) and trichloroethene (TCE) are the predominant contaminants at hazardous waste sites in the United States. Although less prevalent, dichloromethane (DCM) is also found at a number of sites. EPA classifies PCE and DCM as likely to be carcinogenic in humans by all routes of exposure, while TCE is classified as carcinogenic to humans by all routes. At some sites, releases of PCE, TCE and DCM comingle in the groundwater. Field evidence from one such site in California suggests that DCM is used as the electron donor for reductive dechlorination of TCE. Nevertheless, definitive evidence that DCM can serve …

Historical Integration Of Remote Sensing Data: Can Gis Extract Information From Grayscale Aerial Photographs?, Kristina Robertson

All Theses

There have been many changes in land management policies of the National Forest system over the past 100 years. Changes in policy related to law, population growth and economics directly cause changes in land cover. Global land cover changes are occurring at such a pace and magnitude that they are affecting Earth system functioning (Lambin et al., 2001). The analysis of land cover changes plays a key role in understanding several environmental phenomena, resulting in a need for objective and comparable land cover maps (Gennaretti et al., 2011). Advances in remote sensing and Geographic Information Systems (GIS) have modernized land-use …

The Effect Of Food Ingredients On The Oxygen Barrier Properties Of Retort Materials, Amanda Ward

All Theses

An unexplored area in research is addressing how retorted food ingredients interact with retort packaging's oxygen barrier. Ten common food ingredients (whey protein isolate, soy protein isolate, bovine gelatin, fish gelatin, high molecular weight fish gelatin, water, air, oil, potato starch, and hydroxypropyl methylcellulose) were assessed to find their effect on the barrier properties of CPP, PET, and high barrier commercial retort pouches. OxySense Gen III 300 and Mocon OxTran 2/21 were used to evaluate the samples. CPP pouches were first assessed with the OxTran 2/21 and indicated that treatments affected the OTR's of the film materials. However, results from …

Measuring Ligand Exchange On The Surface Of Gold Nanoparticles: A Study Of Competitive Binding Of Ligands Utilizing Fluorescent Resonance Energy Transfer, Daniel D'Unger

All Theses

This study was conducted to track ligand exchange on the surface of metallic nanoparticles in order obtain a better understanding of binding strength of various functional groups. This study develops groundwork for further understanding ligand exchange as nanoparticles transition from engineered to natural systems. A problem exists in knowing the fate of these particles if they are released into natural systems, by accident or with intent. To gain a better understanding of what may occur we look at the binding strength of different ligands. This is done to gain knowledge of the possibility of displacement of ligands occurring in the …

Biomass And Lipid Production From Heterotrophic And Mixotrophic Fed-Batch Cultivations Of Microalgae Chlorella Protothecoides Using Glycerol, Shwetha Sivakaminathan

All Theses

Chlorella protothecoides is a microalga that can grow both photo-autotrophically and/or heterotrophically under different culture and environmental conditions. In this study both the heterotrophic growth and mixotrophic growth have been conducted. The heterotrophic experiments were conducted completely in the dark while the mixotrophic experiments had the dark cycles with periodic light exposure. The aim of the study was to independently understand the effect of each mode on biomass and lipid yields.
For the heterotrophic experiments, glycerol was used as an external organic carbon source while yeast extract was used as the nitrogen source. The carbon and nitrogen source were added …

Microstructural And Mechanical Characterization Of Soy-Based Polyethylene Fibers, Ozgun Ozdemir

All Theses

Bio-composite fibers have attracted increasing attention from environmentally-conscious consumers because of their low cost and biodegradability. Soy protein isolates and other purified forms have been proposed as bio-based substitutes for pure synthetic polymers for use in textiles. However, fibers from pure soy proteins do not possess adequate properties for use as textile fibers. Therefore, this research aimed to investigate composite fibers consisting of soy and polyethylene for their microstructure and mechanical properties. Changes in properties with increasing filler content and long-term properties of fibers were systematically examined.
First, the microstructure of the fibers was investigated by optical analysis. Six different …