Engineering Commons^™

Aligning Anatomical Knee Model With Kinematic Experimental Data To Investigate Squat Exercise, Jose Mario Salinas

Theses and Dissertations

A two-dimensional inverse dynamics anatomical model of the human knee was developed by aligning anatomical structures of the knee (taken from x-rays) with kinematic experimental data (collected from motion capture cameras). The mathematical model was used to study the forces related to the tibiofemoral and patellofemoral joints during the squat and knee extension exercises. Forces calculated by the model included: tibiofemoral contact force, patellofemoral contact force, forces generated by cruciate ligaments, quadriceps force, and patellar tendon force. Bone alignment consisted of superimposing the geometric center of the lateral femoral condyle (from x-rays) with the relative instantaneous center of rotation of …

Radiative Heat Transfer Analysis Of Railroad Bearings For Wayside Thermal Detector Optimization, James Alexandro Aranda

Theses and Dissertations

Wayside hot-box detectors (HBDs) are devices that are currently used to evaluate the health of railcar components including bearings, axles, and brakes by monitoring their temperatures. While HBDs have been instrumental in reducing some train derailments in the past few decades, the number of non-verified bearing removals has increased significantly. In general, HBDs tend to underestimate bearing temperatures in both field service and in laboratory testing, which is not surprising considering the simple two-point calibration method that is used to calibrate these devices. Because of this, different calibrations were compared and analyzed including two-point, three-point, and multi-point calibrations. Analysis of …

Synthesis And Design Of Metals Sulfide/Carbon Composite-Fibers Anodes For Lithium Ion Batteries, Jorge Lopez

Theses and Dissertations

In this study, Forcespinning is used to produce Titanium sulfide (TiS2)/carbon composite fibers for use as lithium-ion battery anodes. The high surface area to volume ratio of the composite fibers can have a high impact on the ionic and electronic conductivity of the active materials leading to improved electrochemical performance of the battery. TiS2 nanoparticles were chosen as the active materials to produce Metal-Li-alloys/C composite fibers due to their high theoretical capacity and low volume change during charge/discharge cycles. The use of a 2-D layered structure of TiS2 nanoparticles in the carbon fiber matrix can greatly accommodate more Li-ions between …

A Systematic Approach To High Blood Pressure Risk Analysis And Healthcare Cost Reduction In Young Adults [Metodología Sistemática Para El Análisis De Riesgo Y Reducción De Costos De Servicios Médicos De Hipertensión En Adultos Jóvenes], Francisco Rafael Torres Diaz

Theses and Dissertations

The purpose of this research is to utilize publicly available data to estimate the current rate of occurrence of undiagnosed High Blood Pressure (HBP) in young adults (18 to 24 years old) and the out-of-pocket healthcare expenses associated with complications of HBP, to provide feasible alternatives to mitigate the effects on a region's economy. This has been done by building a Risk Factor Simulation Model that utilizes known HBP risk factors’ correlation to HBP, insurance coverage data, and rate of diagnosis to formulate the average Risk Factor Value for a region, which through an Annual Expected Cost Function estimates the …

Improving Thermal-Hydraulic Performance Of Flat-Tube Louver-Fin Heat Exchangers By Eliminating Louver Gap Condensate Bridges, Alan L. Jones

Theses and Dissertations

The air side performance of heat exchangers is a well studied subject. Flat-tube louver-fin heat exchangers experience a decrease in performance when operating in dehumidifying conditions. As water vapor is pulled from the air, water condensate may create blockages between louvers. Flat-tube louver-fin heat exchanger may experience a drop in thermal-hydraulic performance by up to 50% due to blockages. The aim of this study is to make macro scale geometric changes to louver dimensions and eliminate louver condensate bridges. By eliminating louver condensate blockages, the heat exchanger should see an overall gain in thermal performance when compared to current fin …

Use Of The Wilshire Equations To Correlate And Extrapolate Creep Data Of Inconel 617 And Nimonic 105, Vito Cedro Iii, Christian Garcia, Mark Render

Mechanical Engineering Faculty Publications and Presentations

Advanced power plant alloys must endure high temperatures and pressures for durations at which creep data are often not available, necessitating the extrapolation of creep life. A recently developed creep life extrapolation method is the Wilshire equations, with which multiple approaches can be used to increase the goodness of fit of available experimental data and improve the confidence level of calculating long-term creep strength at times well beyond the available experimental data. In this article, the Wilshire equation is used to extrapolate the creep life of Inconel 617 and Nimonic 105 to 100,000 h. The use of (a) different methods …

A Parametric Study Of Wave Interaction With A Rotor Having Hydrofoil Blades, Yingchen Yang, Fredrick A. Jenet, Ben Xu, Juan Carlos Garza, Benjamin Tamayo, Yessica Chavez, Oscar Reyes, Samuel Fuentes

Mechanical Engineering Faculty Publications and Presentations

Our recent progress on studying wave interaction with a lift-type rotor is discussed in this paper. The particular focus is on characterization of the rotor’s unidirectional responsiveness in waves. The rotor consists of six hydrofoil blades in two sets. One blade set has three blades laid out as a vertical-axis wind turbine of the Darrieus type. The other blade set has three blades configured like a Wells turbine. In combination, the formed rotor can be driven by flows in any direction to perform unidirectional rotation about its vertically mounted shaft. This unidirectional responsiveness of the rotor also holds in waves, …

Use Of The Wilshire Equations To Correlate And Extrapolate Creep Data Of Hr6w And Sanicro 25, Vito Cedro Iii, Christian Garcia, Mark Render

Mechanical Engineering Faculty Publications and Presentations

Advanced power plant alloys must endure high temperatures and pressures for durations at which creep data are often not available, necessitating the extrapolation of creep life. Many methods have been proposed to extrapolate creep life, and one of recent significance is a set of equations known as the Wilshire equations. With this method, multiple approaches can be used to determine creep activation energy, increase the goodness of fit of available experimental data, and improve the confidence level of calculating long-term creep strength at times well beyond the available experimental data. In this article, the Wilshire equation is used to extrapolate …

Analysis Of Flash In Injection Molding Using Flow Simulation And Design Of Experiments, Claudia Lizette Lopez

Theses and Dissertations

This study presents a method of detecting flash by using flow simulation along with the mold processing conditions and the DOE analysis values from all input and output parameters that will be calculated. All of this would be completed in order to compare and verify the DOE and simulation results and find out if it can be applied to an actual live production molded part, in this case, the Leap char ribbon. This paper will also describe the scrap issue that is presently happening on this molded part, and what are the options that there is in order to find …

Texas Sour Orange Juice Used In Scaffolds For Tissue Engineering, Mandana Akia, Nataly Salinas, Cristobal Rodriguez, Robert Gilkerson, Luis A. Materon, Karen Lozano

Mechanical Engineering Faculty Publications and Presentations

Fine fibers of polyhydroxybutyrate (PHB), a biopolymer, were developed via a centrifugal spinning technique. The developed fibers have an average diameter of 1.8 µm. Texas sour orange juice (SOJ) was applied as a natural antibacterial agent and infiltrated within the fibrous membranes. The antibacterial activity against common Gram-positive and Gram-negative bacteria (Staphylococcus aureus and Escherichia coli, respectively) was evaluated as well as cell adhesion and viability. The PHB/SOJ scaffolds showed antibacterial activity of up to 152% and 71% against S. aureus and E. coli, respectively. The cell studies revealed a suitable environment for cell growth and cell attachment. The outcome …

Forcespinning Of Metal Oxides And Metal Sulfides And Their Applications As Alternative Anode Materials For Lithium-Ion And Sodium-Ion Batteries, Alejandra Valdez

Theses and Dissertations

Molybdenum-Oxide/Carbon (MoO2/C) composite nanofibers were synthesized using Forcespinning method and subsequent heat treatment, for use as anode materials for lithium-ion batteries. Due to the layered structure of MoO2, the composite nanofibers are very promising for use as anode material for LIBs. The MoO2/C composite fiber anodes exhibit good electrochemical performance and cycling stability.

Antimicrobial Properties And Characterization Of Polymer/Composite Nanofibers, David De La Garza

Theses and Dissertations

Pathogenic bacteria have been the cause of many illnesses worldwide due to their rapid growth and reproduction in food and water. Bacteria-resistant antibiotics and kidney complications due to overuse of antibiotics has remained a large public health concern. The goal of this research project was to find an alternative by producing nanofibers that inhibit microbial growth utilizing Forcespinning technology. The Forcespinning of poly(acrylic acid) (PAA) with Single Wall Carbon Nanotubes functionalized with OH (SWCNT-OH) and Ag + flakes were carried out on solutions with different concentrations. Scanning electron microscopy was used to view fiber morphology and investigate the average nanofiber …

4-D Printing Of Pressure Sensors And Energy Harvesting Devices For Engineering Education, Tzu-Liang Bill Tseng, Aditya Akundi, Hoejin Kim

Manufacturing & Industrial Engineering Faculty Publications and Presentations

This paper elaborates on the development of laboratory project modules in the Industrial manufacturing and systems engineering department at The University of Texas El Paso based on Four-Dimensional (4D) printing technology. These modules are aimed at introducing the students to interdisciplinary manufacturing and emerging dimensions in manufacturing technology. 4D printing is a new dimension in additive manufacturing wherein, the 3D printed structures react to the change of parameters within the environment such as temperature, and humidity, resulting in shape change or in functionality such as electricity output, and self-healing. Recently 4D printing of simple devices for pressure sensors application were …

Vibration-Based Defect Detection For Freight Railcar Tapered-Roller Bearings, Joseph Montalvo, Constantine Tarawneh, Arturo A. Fuentes

Mechanical Engineering Faculty Publications and Presentations

The railroad industry currently utilizes two wayside detection systems to monitor the health of freight railcar bearings in service: The Trackside Acoustic Detection System (TADS™) and the wayside Hot-Box Detector (HBD). TADS™ uses wayside microphones to detect and alert the conductor of high risk defects. Many defective bearings may never be detected by TADS™ due to the fact that a high risk defect is considered a spall which spans more than 90% of a bearing’s raceway, and there are less than 20 systems in operation throughout the United States and Canada. Much like the TADS™, the HBD is a device …

Developing And Testing An Electronic Homework System To Improve Student Engagement And Learning In Engineering Thermodynamics, Stephen Crown, Constantine Tarawneh, Jazmin Ley

Mechanical Engineering Faculty Publications and Presentations

An electronic homework delivery system was developed for an advanced undergraduate engineering thermodynamics course due to limitations in available electronic homework systems. A commercially available system was effectively used in the introductory course for simple problems. The complexity of problems in the advanced course made adoption of the same system problematic as students needed feedback in the problem solving process. A system was devised that delivers individual problems to each student, provides feedback throughout the process, and records results for assessment. The system has helped students become more active in homework assignments in both completing assignments and in doing original …

Defect Prognostics Models For Spall Growth In Railroad Bearing Rolling Elements, Nancy De Los Santos, Constantine Tarawneh, Robert E. Jones, Arturo A. Fuentes

Mechanical Engineering Faculty Publications and Presentations

Prevention of railroad bearing failures, which may lead to catastrophic derailments, is a central safety concern. Early detection of railway component defects, specifically bearing spalls, will improve overall system reliability by allowing proactive maintenance cycles rather than costly reactive replacement of failing components. A bearing health monitoring system will provide timely detection of flaws. However, absent a well verified model for defect propagation, detection can only be used to trigger an immediate component replacement. The development of such a model requires that the spall growth process be mapped out by accumulating associated signals generated by various size spalls. The addition …

An Analysis Of The Efficacy Of Wayside Hot-Box Detector Data, Constantine Tarawneh, James Aranda, Veronica Hernandez, Claudia J. Ramirez

Mechanical Engineering Faculty Publications and Presentations

Wayside hot-box detectors (HBDs) are devices that are currently used to monitor bearing, axle, and brake temperatures as a way of assessing railcar component health and to indicate any possible overheating or abnormal operating conditions. Conventional hot-box detectors are set to alarm whenever a bearing is operating at a temperature that is 94.4°C (170°F) above ambient, or when there is a 52.8°C (95°F) temperature difference between two bearings that share an axle. These detectors are placed adjacent to the railway and utilize an infrared sensor in order to obtain temperature measurements. Bearings that trigger HBDs or display temperature trending behavior …

Impact Of Hysteresis Heating Of Railroad Bearing Thermoplastic Elastomer Suspension Pad On Railroad Bearing Thermal Management, Oscar O. Rodriguez, Arturo A. Fuentes, Constantine Tarawneh

Mechanical Engineering Faculty Publications and Presentations

It is a known fact that polymers and all other materials develop hysteresis heating due to the viscoelastic response or internal friction. The hysteresis or phase lag occurs when cyclic loading is applied leading to the dissipation of mechanical energy. The hysteresis heating is induced by the internal heat generation of the material, which occurs at the molecular level as it is being disturbed cyclically. Understanding the hysteresis heating of the railroad bearing elastomer suspension element during operation is essential to predict its dynamic response and structural integrity, as well as to predict the thermal behavior of the railroad bearing …

Development And Optimization Of Alumina Fine Fibers Utilizing A Centrifugal Spinning Process, Mandana Akia, Dulce Capitanachi, Misael E. Martinez, Carlos Hernandez, Hector De Santiago, Yuanbing Mao, Karen Lozano

Mechanical Engineering Faculty Publications and Presentations

Highlights

• Successful synthesis of AIP/PVA composite fibers using Forcespinning® techniques.

• Optimization of the operating parameters applying response surface methodology (RSM).

• Fabrication of mesostructured gamma alumina and highly crystalline alpha alumina fine fibers.

Abstract

Aluminum isopropoxide and poly(vinylalcohol) fine fibers were successfully fabricated and optimized utilizing the response surface methodology. The optimized composite fibers showed mean fiber diameter of 304 nm. The fiber samples were calcined at different temperatures to attain both gamma and alpha phases of alumina. Various characterization methods including scanning electron microscopy, thermogravimetric analysis, x-ray diffraction and nitrogen adsorption/desorption analysis were conducted. The BET analysis …

The Effect Of Heat Generation In The Railroad Bearing Thermoplastic Elastomer Suspension Element On The Thermal Behavior Of Railroad Bearing Assembly, Oscar Osvaldo Rodriguez

Theses and Dissertations

Understanding the internal heat generation of the railroad bearing elastomer suspension element during operation is essential to predict its dynamic response and structural integrity, as well as to predict the thermal behavior of the complete railroad bearing assembly including the bearing adapter. The latter is essential for sensor selection and placement within the adapter (e.g., typical temperature sensors have operating ranges of up to 125°C or 257°F). The internal heat generation is a function of the loss modulus, strain, and frequency. Based on experimental studies, estimations of internally generated heat within the thermoplastic elastomer pad were obtained. The calculations show …

Fibers For Skin Regeneration, Astrid Michelle Rodriguez Negron

Theses and Dissertations

This thesis presents the successful development of biocompatible Polyvinyl Butyral (PVB), PVB/Polylysine and PVB/Tannic Acid (TA)/Polylysine fibers from an ethanol solution, Polyhydroxybutyrate (PHB), PHB/Polylysine, PHB/TA/Polylysine fibers from a chloroform solution and Chitosan (CH)/Pullulan (PL)/TA and CH/PL/TA/Polylysine fibers from an aqueous solution. The fibers were mass produced utilizing the Forcespinning® (FS) technology. The morphology of the fibers was characterized using a scanning electron microscope (SEM) and the fibers average diameter was calculated. The thermal properties of the fibers were characterized using a thermogravimetric analyzer (TGA) and a differential scanning calorimeter (DSC). The antibacterial activity of the fibers was assessed using against …

The Use Of Mixed Organic/Ionic Liquid Electrolytes With Forcespun Metal Oxides/Carbon Microfiber Electrodes In Lithium Ion Batteries, Jahaziel Villarreal

Theses and Dissertations

Conventional Lithium-Ion Battery (LIB) electrolytes have serious safety concerns because of highly flammability. In order to mitigate this drawback, alternative electrolytes with low volatility and non-flammable need to be synthesis. Ionic liquids (ILs) and mixed organic ionic liquid electrolytes (MOILEs) are the most suitable replacement for the highly flammable commercial organic electrolytes. In this academic investigation, a new perspective on the electrochemical performance of the ionic liquid EMI-TFSI as an alternate non-flammable electrolyte. In parallel, the use of Forcespun nanofibers as binder-free anodes will be analyzed to further improve overall electrochemical performance.

Lead Doped Carbon Nanofibers In Li-Ion Batteries, Omar Torres

Theses and Dissertations

Lead acid batteries have been a very reliable rechargeable battery since its inception in the mid-1800s. Lithium-Ion batteries have been sought out for their light-weight and capacity of holding large amounts of energy in a small amount of space. Few studies have been conducted in the use of lead in lithium-ion batteries.

In this thesis, lead-doped carbon nanofibers were produced by using the Forcespinning® method and used as an anode on a lithium-ion battery. The morphology, material characterization and thermal properties of the anode material were analyzed using the Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Thermogravimetric Analysis …

Superharmonic Resonance Of Second Order For Electrostatically Actuated Mems Cantilevers, Martin Amador Botello

Theses and Dissertations

The nonlinear dynamics of electrostatically actuated micro-electro-mechanical system (MEMS) cantilever resonators are investigated. The applied Alternating Current (AC) voltage is in the realm of superharmonic resonance of the second order (near one-fourth of the natural frequency of the resonator) and hard excitations. Method of Multiple Scales (MMS) and Reduced Order Models (ROMs) are used to solve the dimensionless partial differential equation (PDE) of motion along with boundary and initial conditions. MMS transforms the PDE of motion into zero-order and first-order problems. ROMs uses mode shapes of vibration for undamped cantilever resonator as a basis of functions. ROM is …

Multifunctional Carbon Systems (Interlaminated Carbon Nanofiber Mats/ Carbon Nanotubes Polymer Composites), Homero Gonzalez Guardiola

Theses and Dissertations

Carbon nanomaterials have been an attractive topic within diverse industrial sectors given their outstanding properties for decades. One of the properties that has been calling attention is it’s shielding effectiveness (SE) for electromagnetic interference (EMI), because of the constant race of improving portable electronic and wireless communication devices among other applications. The present study, analyzes the properties of interlaminated Carbon Nanofiber (CNF) mats/Carbon Nanotubes (CNT) polymer composites, emphasizing in its capability to shield EMI. The CNF mats were developed with Polyvinyl alcohol (PVA) as a precursor and by means of the Forcespinning® technology which uses centrifugal force to create fibers …

The Use Of Fe3o4/Carbon Composite Fibers As Anode Materials In Lithium Ion Batteries, Howard Campos, Jonathan Ayala, Carolina Valdes, Jason Parsons, Mataz Alcoutlabi

Mechanical Engineering Faculty Publications and Presentations

In the present work, results on the synthesis and mass production of polymer/ceramic composite fibers through Forcespinning® (FS) are reported. Magnetite (Fe3O4), has been considered as a good anode material for Lithium‒Ion Batteries (LIBs) due to its high theoretical capacity (~924 mAhg-1), low cost, and low toxicity. The Fe3O4/carbon composite, in the present study, was achieved through Forcespinning iron (III) acetylacetonate /polyacrylonitrile (PAN) precursor solution with stabilization in air at 280°C followed by carbonization at 600°C under argon. The electrochemical cyclic performance of Fe3O4/C composite fibers was investigated by galvanostatic charge/discharge experiments. The results showed the Fe3O4/C composite fiber anode …

Modeling Of Aggregation And Gelation Of Nanoparticles Using Quadrature Method Of Moments, Elsayed Abdelfatah, Maysam Pournik

Mechanical Engineering Faculty Publications and Presentations

Applications of Nanotechnology are growing significantly in the petroleum industry such as oil recovery, and well stimulation. In aqueous media, silica nanoparticles aggregate if there is sufficient attractive energy between nanoparticles. Aggregate size distribution evolves as aggregation continues, and once it spans the space, it forms a gel. The objective of this study is to study the aggregation and gelation kinetics in the batch. Population Balance equation (PBE) is used to model the kinetics of aggregation. Quadrature method of moments (QMOM) is used to convert the PBE with continuous distribution of nanoparticle size into a set of moment equations for …

Functionalized Graphene Oxide As Reinforcement In Epoxy Based Nanocomposites, F. V. Ferreira, F. S. Brito, W. Franceschi, E. A. N. Simonetti, L. .S Cividanes, Mircea Chipara, Karen Lozano

Mechanical Engineering Faculty Publications and Presentations

The effects of amine-modified graphene oxide on dispersion and micro-hardness of epoxy based nanocomposites are reported. Graphene oxide was prepared by the modified Hummers method followed by hexamethylenediamine functionalization. Analysis conducted through Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy-based infrared spectroscopy show that the functionalization process effectively promoted a replacement of oxygen with amine groups while simultaneously creating defects in the graphitic structure. An increase in hardness was observed for the developed nanocomposites.

Direct Numerical Simulation Of Transverse Ripples: 1. Pattern Initiation And Bedform Interactions, ‪Nadim Zgheib, J. J. Fedele, D. C. J. D. Hoyal, M. M. Perillo, S. Balachandar

Mechanical Engineering Faculty Publications and Presentations

We present results of coupled direct numerical simulations between flow and a deformable bed in a horizontally periodic, turbulent open channel at a shear Reynolds number of Reτ = 180. The feedback between the temporally and spatially evolving bed and the flow is enforced via the immersed boundary method. Using the near-bed flow field, we provide evidence on the role of locally intense near-bed vortical structures during the early stages of bed formation, from the emergence of quasi-streamwise streaks to the formation of incipient bedform crestlines. Additionally, we take a new look at a number of defect-related bedform interactions, …

Direct Numerical Simulation Of Transverse Ripples: 2. Self-Similarity, Bedform Coarsening, And Effect Of Neighboring Structures, ‪Nadim Zgheib, J. J. Fedele, D. C. J. D. Hoyal, M. M. Perillo, S. Balachandar

Mechanical Engineering Faculty Publications and Presentations

Coupled bed-flow direct numerical simulations investigating the early stages of pattern formation and bedform (ripple) interactions were examined in a previous paper (Part 1), making use of the resolved flow field. In this paper (Part 2), we compare our results to published experimental data and provide an extensive quantitative analysis of the bed using spectral analysis and two-point correlations. The effect of the mobile rippled bed on the flow structure and turbulence is investigated locally (at specific streamwise locations) and over the entire computational domain. We show that developing ripples attain a self-similar profile in both the shape and the …