Engineering Commons^™

Low Melting Glass Frit As An Adhesion And Resistivity Promotor To Silver Nanoparticle Ink Photonically Sintered On Indium Tin Oxide Coated Glass, Jason J. Kleiner

Masters Theses

The objective of this study was the fabrication of a printed circuit resulting from the photonic drying/sintering of conductive circuits, printed using silver nano ink layered on a film of low melting glass frit onto indium tin oxide (ITO) coated glass substrate through the flexographic printing method. The fabrication process flow included material preparation, printing, and photonic drying/sintering in that order.

Investigation of the breakthrough photonic drying/sintering method was studied by varying sintering parameters, specifically the amount of heat energy applied to each specimen, and the speed at which it was applied. Additionally, the adhesion promoting properties of a never …

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 …

Development, Optimization, And Implementation Of A Vibration Based Defect Detection Algorithm For Railroad Bearings, Amy Gonzalez

Theses and Dissertations - UTB/UTPA

Of the three main rail accident types in the United States, derailments are the most common. Studies have shown that derailments occurring above 25 mph are caused by equipment failures such as bearing failures. As a preventative measure, condition-monitoring systems are required to detect defective bearings in the field. Based on data compiled from multiple experiments of healthy and defective bearings at UTPA, an algorithm has been devised to identify bearing abnormalities. Vibration analysis techniques are utilized to potentially determine whether a bearing is defective and the defect type and size using the acquired vibration signatures. Implementation of a defect …

Onboard Load Sensor Prototype For Use In Freight Railcar Service, Thomas Michael Diedrich

Theses and Dissertations - UTB/UTPA

Determining the exact load carried by an individual railcar is crucial in the railroad industry. With an accurate load measurement, the filling process can be optimized to provide maximum cargo load without exceeding the loading thresholds set by the Association of American Railroads (AAR). In addition to optimizing the cargo load, an accurate load measurement will make it possible to identify any load imbalance in the railcar which has detrimental effects on bearing. Previous work conducted with a strain-gauge-based load sensor suspended between a thermoplastic steering pad and a bearing adapter provided accurate load data in the laboratory setting. This …

Nonlinear Dynamics Of Electrostatically Actuated M/Nems Plates To Include Casimir And Van Der Waals Effects, Reynaldo Oyervides

Theses and Dissertations - UTB/UTPA

The amplitude-frequency response and voltage-amplitude response of electrostatically actuated micro and nano-electromechanical systems (M/NEMS) clamped circular plates are investigated. The system is actuated by soft AC voltage at frequency near half natural frequency of the plate, and another case near natural frequency of the plate, they resulting in primary and parametric resonances of the system, respectively. The system is first analytically modeled using the Method of Multiple Scales (MMS). MMS results are then compared to Reduced Order Model (ROM) method frequency response numerical simulations. Besides MMS and ROM, time response simulations are conducted. The agreement of the frequency responses of …

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 …

Optical Anisotropy Of Porous Polymer Film With Inverse Slanted Nanocolumnar Structure Revealed Via Generalized Spectroscopic Ellipsometry, Dan Liang, Derek Sekora, Charles Rice, Eva Schubert, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

We use generalized spectroscopic ellipsometry to characterize the biaxial optical properties of porous polymer and slanted nanocolumnar template thin films. The porous polymer with inverse columnar structure was prepared via infiltrating polymer into the voids of the slanted nanocolumnar film and selectively removing the column material (cobalt). The anisotropic Bruggeman effective medium approximation was employed to analyze the ellipsometry data of the porous polymer film and nanocolumnar template. The classification and structure of optical anisotropy are found to be identical for both samples. The interchangeable optical behaviors between two complementary structures are attributed to the equivalency in their anisotropic polarizabilities.

Dynamic Characteristics And Seismic Response Analysis Of A Long-Span Steel-Box Basket-Handle Railway Arch Bridge, Xuhui He, Biao Wei, Yunfeng Zou, Dongyang Hu, Daniel G. Linzell

Department of Civil and Environmental Engineering: Faculty Publications

The inside oblique angle between the vertical plane and the arch rib has been shown to be one of the main factors influencing dynamic properties of long-span steel-box basket-handle arch bridges. Details related to the extent, that the inside oblique angle influenced the dynamic characteristics and the seismic response of the arch bridge under the combined longitudinal and vertical seismic excitation and under the combined lateral and vertical seismic excitation, were reported herein. Four oblique angles (0°, 3°, 4.8°, and 6°) were selected based on the arch ribs height and bridge deck width. Findings suggested that a larger inside oblique …

Estimation Of Historic Flows And Sediment Loads To San Francisco Bay, 1849 – 2011, Hamed Moftakhari Rostamkhani, David A. Jay, Stefan A. Talke, David H. Schoellhamer

Civil and Environmental Engineering Faculty Publications and Presentations

River flow and sediment transport in estuaries influence morphological development over decadal and century time scales, but hydrological and sedimentological records are typically too short to adequately characterize long-term trends. In this study, we recover archival records and apply a rating curve approach to develop the first instrumental estimates of daily delta inflow and sediment loads to San Francisco Bay (1849 – 1929). The total sediment load is constrained using sedimentation/erosion estimated from bathymetric survey data to produce continuous daily sediment transport estimates from 1849 to 1955, the time period prior to sediment load measurements. We estimate that ~55% (45 …

Evaluating The Use Of Crowdsourcing As A Data Collection Method For Bicycle Performance Measures And Identification Of Facility Improvement Needs, Miguel A. Figliozzi, Bryan Philip Blanc

Civil and Environmental Engineering Faculty Publications and Presentations

This research developed a smartphone application called ORcycle to collect cyclists’ routes, users, and comfort levels. ORcycle combines GPS revealed route data collection with new questionnaires that try to elicit cyclists’ attitudes as well as comfort levels and factors that influence their perceived comfort and route choice. The new questionnaires were developed to better understand how cyclists’ comfort levels are affected by route characteristics, route stressors, safety reports, cyclists’ demographics, and cyclists’ cycling attitude. Preliminary results show that many trip characteristics, route choice factors, route stressors and demographic variables are correlated with comfort levels. ORcycle is the first statewide deployment …

Improved Safety Performance Functions For Signalized Intersections, Karen Dixon, Christopher Monsere, Raul Avelar, Joel Stephen Barnett, Paty Escobar, Sirisha Murthy Kothuri

Civil and Environmental Engineering Faculty Publications and Presentations

For this effort, the research team developed new safety performance functions (SPFs) for signalized intersections in Oregon. The modeling dataset consisted of 964 crashes from a total of 73 intersections that were randomly selected based on the presence of a traffic signal (identified through the crash data records). The SPFs were developed using a Poissonlognormal Generalized Linear Mixed model framework for total crashes and severe injury crashes (coded as KAB). Three SPFs were developed: 1) an SPF for total crashes, which relies on both major and minor AADTs to predict the expected number of crashes; 2) an SPF for KAB …

Common Calibration Standards For Visible/Infrared Optical Sensors Are Essential To Multi-Sensor Missile Defense Architectures, Joe Tansock, Alan Thurgood, Bruce Guilmain, Garry Schnelzer

Space Dynamics Laboratory Publications

Outline

• What is calibration and why is it important?
• What calibration provides to visible/infrared optical sensors being used for missile defense
• Mapping of missile defense needs to calibration domains
• Calibration planning
• Calibration examples (airborne and spaceborne)
• Summary

Optical Tracking System To Monitor Laparoscopic Training, William D. Rytlewski

Masters Theses

Laparoscopic Surgery, also known as Minimally Invasive Surgery, is a surgical technique where surgeons perform surgery through small incisions in the patient’s abdomen using a camera to monitor the movements of the instruments inside the patient. In order for the surgery to be performed, the surgeon must possess a unique set of skills obtained through training using a variety of techniques. Simulators are the preferred method of training for laparoscopic surgery since they provide medical residents with real world scenarios as well as a tremendous amount of feedback on what he/she did wrong or right. However, due to the high …

Human Intracranial High Frequency Oscillation Detection Using Time Frequency Analysis And Its Relation To The Seizure Onset Zone, Riazul Islam

Masters Theses

One third of the patients diagnosed with focal epilepsy do not respond to antiepileptic drugs. For these patients the possible diagnosis options to give seizure freedom or at least reduce seizure frequencies significantly would be surgical resection or seizure interrupting implantable devices. The success of these procedures depends on accurate detection of the region causing seizure also known as epileptic zone. This requires detail pre-surgical evaluation including Invasive Video Electroencephalographic Monitoring (IVEM). The resulting great volume of intracranial Electroencephalography (iEEG) signal is visually examined by an expert epileptologist which can be time consuming, extremely complex, and not always effective. We …

Wet Chemical Synthesis And Characterization Of Nanomaterials For Solar Cell Applications, Krystle N. Sy, Ramprasad Gandhiraman, Jessica E. Koehne

STAR Program Research Presentations

During long term space missions, it is necessary to have a reliable source of energy. Solar cells are an easy and reliable way to convert energy from the sun to electrical energy. NASA has used solar cells manufactured on Earth as an energy source for many of its missions. In order to develop technologies that will enable high efficiency solar cells, we are synthesizing nanostructured materials. A range of nanostructured materials, such as titanium dioxide nanowires, nickel nanoparticles, copper nanoparticles, and silver nanoparticles/nanowires, are synthesized. In this work, we are reporting on the synthesis of these nanomaterials and the electron …

A Survey Of Applications And Human Motion Recognition With Microsoft Kinect, Roanna Lun, Wenbing Zhao

Electrical and Computer Engineering Faculty Publications

Microsoft Kinect, a low-cost motion sensing device, enables users to interact with computers or game consoles naturally through gestures and spoken commands without any other peripheral equipment. As such, it has commanded intense interests in research and development on the Kinect technology. In this paper, we present, a comprehensive survey on Kinect applications, and the latest research and development on motion recognition using data captured by the Kinect sensor. On the applications front, we review the applications of the Kinect technology in a variety of areas, including healthcare, education and performing arts, robotics, sign language recognition, retail services, workplace safety …

Functional Thinking: A Protocol Study, Ashwinraj Thiagarajan

All Theses

This thesis reports a protocol study that examines how designers construct function structure graphs as they understand and develop solutions for novel design problems. Eight voluntary design engineers, with two to four years of experience in product design and function modeling are presented with a novel design problem for which they have to develop functional models as part of concept development. The modeling actions are video recorded and the data is analyzed using a predefined protocol that encodes the addition, deletion, and modification of model elements such as functions, flows, and text, and also other activities such as reading the …

Influence Of Low Shear And Cyclic Strain On Hyperglycemic Rat Aortic Smooth Muscle Cells: An In Vitro Dynamic Disease Model, Varun Chawla

All Theses

Vascular complications are the leading cause of morbidity and mortality amongst diabetic patients which represent a major proportion of patients undergoing coronary artery revascularization. Major advances in drug eluting stent technologies have reduced the overall rates of restenosis in general however diabetic patients still remain at a high risk thus requiring target lesion revascularization more commonly as compared to non-diabetic cohort. Phenotypic modulation demonstrated by smooth muscle cells is essential for normal wound healing response however is also contributive to initiation and development of various vascular complications including neointimal hyperplasia which ultimately leads to the lumen re-narrowing or restenosis. Hyperglycemia …

Quantum-Mechanical Calculations Of Actinyl And Europium Sorption To Graphene Oxide, Edward Helvenston

All Theses

Quantum-mechanical calculations were performed to model the interactions of U(VI), Np(V), Pu(VI), and Eu(III) with carboxyl and hydroxyl functional groups of graphene oxide (GO). Models were created for sorption to a single sheet of GO. For U(VI) and Eu(III), models were also created for sorption to two sheets to evaluate the possibility of cation-induced GO aggregation via cation cross-linking of GO sheets. The quantum-mechanical calculations were used to characterize the sorption reactions in terms of energetics and vibrational peak shifts. The calculations performed used Gaussian09 with the B3LYP hybrid functional. Sorption was seen as favorable for all cations considered; the …

Self-Adapting Parallel Framework For Long-Term Object Tracking, Salim Mohammed Ali

All Theses

Object tracking is a crucial field in computer vision that has many uses in human-computer interaction, security and surveillance, video communication and compression, augmented reality, traffic control, etc. Many implementations are introduced in practice, and yet recent methods emphasize on tracking objects adaptively by learning the object’s perspectives and rediscovering it when it becomes untraceable, so that object’s absence problem (in case of occlusion, cluttering or blurring) is resolved. Most of these algorithms have high computational burden on the computational units and need powerful CPUs to attain real-time tracking and high bitrate video processing. These computational units may handle no …

Development And Validation Of An Optically-Based Strain Measuring Orthopaedic Screw For Fracture Fixation Implants, Nakul Ravikumar

All Theses

In the USA over 28 million musculoskeletal injuries are treated annually, including 2 million fracture fixation surgeries (about 0.5% of the population).[1] Treatment of large osseous defects use allografts which have failure rates of up to 25%, and complication rates as high as 30-60%.[2] Fracture fixation usually involves mechanical fixation with rods, plates and/or screws which repair slowly and are susceptible to infection. Implant infection and loosening are serious concerns, but can currently only be measured through expensive instrumented implants, biopsy culture, or radiographs. However, none of these directly quantify implant loading and stability. There is therefore a need for …

Sensitivity And Precision Analysis Of The Graph Complexity Connectivity Method, Sudarshan Sridhar

All Theses

In the Graph Complexity Connectivity Method (GCCM), twenty nine complexity metrics applied against engineering design graphs are used to create surrogate prediction models of engineering design representations (assembly models and function structures) for given product performance values (assembly time and market value). The performance of these prediction models has been previously assessed solely based on accuracy. In this thesis, the predictive precision of the surrogate models is evaluated in order to assess the GCCM's ability to generate consistent results under the same conditions. The Assembly Model - Assembly Time (AM-AT) prediction model performed the best in terms of both accuracy …

Inertial Focusing Of Particles In Curved Microchannels, Ketaki Joshi

All Theses

Since the beginning of microfluidics, the ability to control motion of particles in microchannels has always been fascinating. Microfluidic techniques such as dielectrophoresis, magnetophoresis rely on externally applied fields to separate particles while others like hydrophoresis and deterministic lateral displacement depend on low Reynolds number operation for particle manipulation. One of these techniques is inertial focusing of particles in microchannels. The particles and channel interact to cause lateral migration of particles to equilibrium positions within channel cross-section in flow regime where inertia and viscosity of fluid are finite. Inertial focusing has wide range of applications in fields of chemical synthesis, …

Microcosm Evaluation Of Enhanced Bioremediation For Halogenated Methanes At A Former Industrial Site, Hao Wang

All Theses

Halogenated methanes are among the most frequently encountered contaminants at hazardous waste sites. One such site in California is contaminated with chloroform (CF), carbon tetrachloride (CT), and trichlorofluoromethane (CFC-11). CF, CT and CFC-11 are the main focus of this research; they are present at the California site at concentrations in the mg per liter range and a plume of contaminated groundwater emanating from a source zone is approaching a property boundary, necessitating remediation. Anaerobic bioremediation is one of the technologies under consideration for addressing the source zone and the less concentrated downgradient plume. A microcosm study was performed to evaluate …

Exploring The Potential Impact Of Meditation Intervention On Stroke Trends In The United States., Raj Ambavane

All Theses

Meditation has shown promise in clinical trials in reducing systolic blood pressure, one of the main causes of stroke. We explore the potential impact of expanding meditation intervention on stroke trends in the US. We developed a dynamic population simulation in which the progression of each individual is governed by a micro-simulation model. We calibrated the micro-simulation model for stroke incidence and further validated it by comparing the stroke-related mortality for each age group generated by the model with that observed in the US. We used the population simulation model to estimate the effects of mindfulness meditation intervention on stroke …

Evaluation Of Shiryaev-Roberts Procedure For On-Line Environmental Radiation Monitoring, Mara Watson

All Theses

An on-line radiation monitoring system that simultaneously concentrates and detects radioactivity is needed to detect an accidental leakage from a nuclear waste disposal facility or clandestine nuclear activity. Previous studies have shown that classical control chart methods can be applied to on-line radiation monitoring data to quickly detect these events as they occur; however, Bayesian control chart methods were not included in these studies. This work will evaluate the performance of a Bayesian control chart method, the Shiryaev-Roberts (SR) procedure, compared to classical control chart methods, Shewhart 3-σ and cumulative sum (CUSUM), for use in on-line radiation monitoring of 99Tc …

Comparison Gmm And Svm Classifier For Automatic Speaker Verification, Shamama Afnan

All Theses

The objective of this thesis is to develop automatic text-independent speaker verification systems using unconstrained telephone conversational speech. We began by performing a Gaussian Mixture Model Likelihood ratio verification task in speaker independent system as described by MIT Lincoln Lab. We next introduced a speaker dependent verification system based on speaker dependent thresholds. We then implemented the same system applying Support Vector Machine. In SVM, we used polynomial kernels and radial basis function kernels and compared the performance. For training and testing the system, we used low-level spectral features. Finally, we provided a performance assessment of these systems using the …

Biodegradation Of Hexahydro-1,3,5-Trinitro-1,3,5-Triazine (Rdx) Using Photosynthetic Bacteria, Sarah Galloway

All Theses

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is an emerging contaminant according to the Environmental Protection Agency (EPA). RDX was introduced as a secondary explosive during World War II. It is still used in many explosive such as hand grenades. RDX enters the environment mostly through the manufacturing process or from the use of explosives. RDX is a suspected carcinogen and can also affect the nervous system of humans. Therefore, RDX has become a chemical of concern across many United States military bases and open and closed manufacturing plants. The goal of this research was to evaluate the biodegradation of RDX via two phototrophic bacteria: …

Design Of Cab Suspensions And Semi-Active Seat Damping Control Strategies For Tractor Semi-Trailers, Judhajit Roy

All Dissertations

This thesis uses a high fidelity vertical plane ride model of the tractor semi-trailer to study the effect of different cab design configurations and semi-active seat damper control strategies on the driver’s ride comfort.

The secondary suspensions of a tractor have been an area of particular interest because of the considerable ride comfort improvements they provide. A gap exists in the current engineering domain of an easily configurable high fidelity low computational cost simulation tool to analyze the ride of a tractor semi-trailer. A 15 degree of freedom model of the tractor semi-trailer was used to develop a simulation tool …

Manipulation Of The Electrical Double Layer For Control And Sensing In A Solid State Nanopore, Samuel L. Bearden

All Dissertations

Nanopores have been explored with the goal of achieving non-functionalized, sub-molecular sensors, primarily with the purpose of producing fast, low-cost DNA sequencers. Because of the nanoscale volume within the nanopore structure, it is possible to isolate individual molecular and sub-molecular analytes. Nanopore DNA sequencing has remained elusive due to high noise levels and the challenge of obtaining single-nucleotide resolution. However, the complete electrical double layer within the nanopore is a key feature of fluid-nanopore interaction and has been neglected in previous studies. By exploring interactions with the electrical double layer in various nanopore systems, we characterize the material, electrical, and …