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- Theses and Dissertations - UTB/UTPA (14)
- Mechanical Engineering Faculty Publications and Presentations (3)
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Articles 1 - 21 of 21
Full-Text Articles in Engineering
Improving The Mechanical Properties Of Polymers By Adding Self-Healing Capabilities, Alma Perez
Improving The Mechanical Properties Of Polymers By Adding Self-Healing Capabilities, Alma Perez
Theses and Dissertations - UTB/UTPA
The addition of self-healing capabilities to polymers through the dispersion of First Generation Grubbs’ Catalyst (FGGC) and poly(urea-formaldehyde) (PUF) microcapsules filled with dicyclopentadiene (DCPD) as the healing agent, has been investigated by various experimental techniques such as Optical microscopy, Scanning Electron Microscopy, Tensile tests, Raman Spectroscopy, and Themogravimmetric Analysis (TGA). Optical and Scanning Electron Microscopy revealed the morphology of the surface of the PUF microcapsules, the diameter size distribution and the thickness of the shell, and their structure when dispersed in the polymeric matrices. Photos taken after the tensile test showed broken microcapsules on both polymer matrices having released the …
Development Of Algorithms And Criteria For Continuous Condition Monitoring Of Railroad Bearings, Sean Michael Woods
Development Of Algorithms And Criteria For Continuous Condition Monitoring Of Railroad Bearings, Sean Michael Woods
Theses and Dissertations - UTB/UTPA
This thesis summarizes research conducted at the University of Texas-Pan American to investigate the implementation of condition monitoring algorithms for use with railway roller bearings equipped with wireless temperature sensor nodes. Current temperature based condition monitoring techniques utilize wayside detection equipment intermittently located along the track to garner sporadic bearing cup temperatures. Such devices are not capable of detecting brief transient temperature trending events. The developed algorithms were tested using a fleet of ten railway freight cars instrumented with wireless sensor nodes and operated by an Australian freight transportation company. Eighteen months of continuous monitoring combined with the inspection of …
Defect Detection In Railroad Tapered-Roller Bearings Using Vibration Analysis Techniques, Iris L. Alvarado
Defect Detection In Railroad Tapered-Roller Bearings Using Vibration Analysis Techniques, Iris L. Alvarado
Theses and Dissertations - UTB/UTPA
Derailments can often lead to great damage, loss of lives, and massive costs associated with the railroad infrastructure. A significant cause of derailments is premature bearing failure, and therefore bearing condition-monitoring systems that can detect developing defects are of great importance. Based on an investigation conducted at the University of Texas-Pan American on the development of a vibration and temperature monitoring system, an algorithm is devised utilizing various vibration analysis techniques. The proposed algorithm determines whether a bearing is defective, the type of defect present, the defective component (i.e. cup, cone, or roller), and the size of the defect. Speed-dependent …
Fabrication And Characterization Of Polylactic Acid And Polylactic Acid/Multi-Walled Carbon Nanotube Nanofibers Through Centrifugal Spinning, Richard Patlan
Fabrication And Characterization Of Polylactic Acid And Polylactic Acid/Multi-Walled Carbon Nanotube Nanofibers Through Centrifugal Spinning, Richard Patlan
Theses and Dissertations - UTB/UTPA
Biocompatible polymer nanofibers hold great potential in the biomedical engineering field. Their biodegradable nature and enhanced properties could help solve a wide array of health related problems, particularly in the areas of tissue regeneration, drug delivery, and biosensor design. The novel ForcespinningTM method allows the production of submicron fibers without many of the drawbacks found in electrospinning, while also providing a substantial increase in fiber production. The aim of the study was to utilize this method to fabricate non-woven nanofibrous mats composed of polylactic acid (PLA) and polylactic acid/multi-walled carbon nanotube composite fibers. The morphology, thermal properties, and crystalline structure …
Development Of A Vibration And Temperature Measurement Device For Railroad Bearings, Andrea P. Arguelles
Development Of A Vibration And Temperature Measurement Device For Railroad Bearings, Andrea P. Arguelles
Theses and Dissertations - UTB/UTPA
Bearing related derailments cause very high cost and inconvenience to the railroad industry. Various wayside detection systems have been implemented to assess bearing condition and prevent premature failure. However, current devices fail to determine the internal condition of bearings or provide insight regarding the danger and severity of defects and abnormalities that may be present. To this end, a device combining both temperature and vibration detection was designed to be embedded in railroad bearing adapters. In order to efficiently design a railroad bearing condition-monitoring system, two factors that must be considered are the capabilities available to operate the different sensors …
Control Charts For First Order Autoregressive Analysis With An Exogenous Variable, Becky M. Vela
Control Charts For First Order Autoregressive Analysis With An Exogenous Variable, Becky M. Vela
Theses and Dissertations - UTB/UTPA
There are many instances in industry, where the necessity of prediction models is extremely important. However, the difficulty of forecasting increases with the number of variables involved, and determining independent variables from dependent variables. Autocorrelation is one of the most common causes for many control charts and other quality measurement tools to falsely signal an error in the process. Time series models, such as autoregressive models, accommodate autocorrelated data to a certain extent. However, using a model that only analyzes historical data alone does not possess the accuracy necessary to be able to forecast data precisely. An addition of an …
Evaluation Of Security Availability Of Data Components For A Renewable Energy Micro Smart Grid System, Leonel Aguilera Zambrano
Evaluation Of Security Availability Of Data Components For A Renewable Energy Micro Smart Grid System, Leonel Aguilera Zambrano
Theses and Dissertations - UTB/UTPA
In this thesis, we study the development and security testing of photovoltaic data collection system. With the introduction of the smart grid concept, a lot of research has been done on the communication aspect of energy production and distribution throughout the power network. For Smart Grid, Internet is used as the communication medium for specific required services and for data collection. Despite all the advantages of the Smart Grid infrastructure, there is also some security concern regarding the vulnerabilities associated with internet access. In this thesis, we consider security testing of the two most popular and globally deployed web server …
Droplet Spray Behavior Of An Atomization-Based Cutting Fluid (Acf) System For Machining Of Titanium Alloys, Chandra Nath, Shiv G. Kapoor, Anil K. Srivastava, Jon Iverson
Droplet Spray Behavior Of An Atomization-Based Cutting Fluid (Acf) System For Machining Of Titanium Alloys, Chandra Nath, Shiv G. Kapoor, Anil K. Srivastava, Jon Iverson
Manufacturing & Industrial Engineering Faculty Publications and Presentations
The aim of this research is to study droplet spray characteristics of an atomization-based cutting fluid (ACF) spray system including droplet entrainment angle and flow development regions with respect to three ACF spray parameters, viz., droplet and gas velocities, and spray distance. ACF spray experiments are performed by varying droplet and gas velocities. The flow development behavior is studied by modeling the droplets entrainment mechanism, and the density and distribution of the droplets across the jet flare. Machining experiments are also performed in order to understand the effect of the droplet spray behavior on the machining performances, viz., tool life/wear, …
Modeling And Simulation Of Pressure Waves Generated By Nano-Thermite Reactions, Karen S. Martirosyan, Maxim Zyskin, Charles M. Jenkins, Yasuyuki Horie
Modeling And Simulation Of Pressure Waves Generated By Nano-Thermite Reactions, Karen S. Martirosyan, Maxim Zyskin, Charles M. Jenkins, Yasuyuki Horie
Physics and Astronomy Faculty Publications and Presentations
This paper reports the modeling of pressure waves from the explosive reaction of nano-thermites consisting of mixtures of nanosized aluminum and oxidizer granules. Such nanostructured thermites have higher energy density (up to 26 kJ/cm3) and can generate a transient pressure pulse four times larger than that from trinitrotoluene (TNT) based on volume equivalence. A plausible explanation for the high pressure generation is that the reaction times are much shorter than the time for a shock wave to propagate away from the reagents region so that all the reaction energy is dumped into the gaseous products almost instantaneously and thereby a …
Adding Autonomic Healing Capabilities To Polyethylene Oxide, Dorina M. Chipara, Maritza Flores, Alma Perez, Nancy Puente, Karen Lozano, Mircea Chipara
Adding Autonomic Healing Capabilities To Polyethylene Oxide, Dorina M. Chipara, Maritza Flores, Alma Perez, Nancy Puente, Karen Lozano, Mircea Chipara
Mechanical Engineering Faculty Publications and Presentations
The addition of autonomic healing (frequently defined as self-healing) capabilities to a water-soluble polymer (polyethylene oxide, PEO) is for the first time reported. The self-healing system consists of urea-formaldehyde microcapsules filled with dicyclopentadiene and first-generation Grubbs catalyst, dispersed within polyethylene oxide. Raman spectroscopy, optical microscopy, electron microscopy, and thermogravimetric analysis were used to characterize this autonomic healing system. Self-healing capabilities were confirmed by mechanical testing (load–displacement, engineering stress–engineering strain, and true stress–true strain dependences) recorded at very slow elongation rates (0.01 mm/s). The testing fate was chosen to allow for the complete consumption of the monomer before fracture (the polymerization …
Remanufacturing Cleaning Process Evaluation, Comparison And Planning, Ozan Yagar
Remanufacturing Cleaning Process Evaluation, Comparison And Planning, Ozan Yagar
Theses and Dissertations - UTB/UTPA
This thesis aims to combine previous research on remanufacturing cleaning processes and applications into a single decision-making tool, in the form of software, which a remanufacturer can use to find a cleaning system that matches their specific demands. This thesis will provide an in-depth review of each cleaning process, the chemicals used in those processes, and the contamination types for which they were developed. This research also provides evaluation and comparison that assists remanufacturers in designing their cleaning systems. Finally, there will be a description and demonstration of the software. The ultimate goal is to find correct cleaning process to …
A Case Study For Financial Feasibility Of Automated Costing Support In A Small Machine Shop, Benito A. Gonzalez
A Case Study For Financial Feasibility Of Automated Costing Support In A Small Machine Shop, Benito A. Gonzalez
Theses and Dissertations - UTB/UTPA
A knowledge-based cost estimating expert system is chosen by a Mexican machine shop. Differences between the traditional experience-based system employed and the automated system are studied. Data is gathered to analyze time effectiveness, accuracy and payback of the software. Data from seventy part models is recorded to study the time experiment, and data from fifty part models is used to study the accuracy and consistency. Data is analyzed by calculating mean, standard deviation, and test of hypothesis. The results indicate that the software is faster than the traditional quoting system; however, the payback point is high. Also, results show the …
Load Sensor In An Elastomer Suspension Element, Jazmin Ley
Load Sensor In An Elastomer Suspension Element, Jazmin Ley
Theses and Dissertations - UTB/UTPA
Knowledge of the loading applied to railcar suspension elements is necessary for improved rail safety, efficiency, and for monitoring bearing health. An economical, reliable system for keeping track of both dynamic and static loads on a rail car bearing offers potential for many improvements in rail service. The difficulties of implementing such a system are considerable because the sensor must be in the bearing load path and is thus subject to all the stressors of that environment including high impact, high load, high temperature, and corrosion. This thesis describes an attempt to incorporate a load measurement system in a polyurethane …
2d Modeling Of Forcespinning™ Nanofiber Formation With Experimental Study And Validation, Simon Padron
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 …
Production And Characterization Of Biodegradable Nanofibers Via Forcespinning™ Technology, Zachary T. Mceachin
Production And Characterization Of Biodegradable Nanofibers Via Forcespinning™ Technology, Zachary T. Mceachin
Theses and Dissertations - UTB/UTPA
Among the myriad of methods for polymer nanofiber production, there are only a few methods that can produce submicron range fibers in bulk from melt or solution samples. The Forcespinning™ method allows a substantial increase in sample yield; this greatly reduces the time needed to produce bulk quantities of fibers which may be critical in many fields of research and industry, in particularly in fields relating to biopolymers. The aim of the first study was to utilize this method to form non-woven mats of polycaprolactone (PCL) nanofibers and to quantitatively analyze the production and characterization of the produced fibers. The …
Nanoenergetic Composite Based On I2o5/Al For Biological Agent Defeat, Mkhitar Hobosyan, Alexander V. Kazanksy, Karen S. Martirosyan
Nanoenergetic Composite Based On I2o5/Al For Biological Agent Defeat, Mkhitar Hobosyan, Alexander V. Kazanksy, Karen S. Martirosyan
Physics and Astronomy Faculty Publications and Presentations
The risk of bioterrorism events involving the intentional airborne release of contagious agents has led to development of new approaches for bio agent defeat technologies both indoors and outdoors. This report describes nanoenergetic gas generators (NGG) system that exhibit long term stability and superior release of biocidal substances for destruction of pathogenic bacteria. The effect of iodine vaporization on destroying of Escherichia coli (E-coli, HB101 K-12 strain) by using expressing Green Fluorescent Protein (GFP) was investigated. HB101 K-12 has been genetically modified to prevent its growth unless grown on an enriched medium. To obtain quantitative data we used pGLO transformation …
Implementation Of Wireless Temperature Sensors For Continuous Condition Monitoring Of Railroad Bearings, Andoni Zagouris Ii
Implementation Of Wireless Temperature Sensors For Continuous Condition Monitoring Of Railroad Bearings, Andoni Zagouris Ii
Theses and Dissertations - UTB/UTPA
At present there are no existing bearing health monitoring systems capable of continuous monitoring of railroad bearings. Current wayside equipment is used to collect intermittent bearing temperatures, which at times could be every 65 km (~40 mi). To answer this need, IONX, LLC, a subsidiary of Amsted Rail, Inc., has developed low power Wireless Sensor Nodes (WSNs) which can be retrofitted to existing bearing adapters. The WSNs provide continuous monitoring of bearing temperatures as well as the current ambient temperature. Since the nodes are affixed to the bearing adapter surface, a correlation is necessary to estimate the bearing cup temperature …
Development And Testing Of An Actively Adjustable Stiffness Mechanism, Eleazar Marquez, Robert Freeman, Horacio Vasquez
Development And Testing Of An Actively Adjustable Stiffness Mechanism, Eleazar Marquez, Robert Freeman, Horacio Vasquez
Mechanical Engineering Faculty Publications and Presentations
This study presents the comparison of the theoretical and experimental results of the performance of an adjustable stiffness mechanism. In particular, the use of redundant actuation is emphasized in the design of a one degree-of-freedom Watt II mechanism capable of independently controlling the effective stiffness without a change in equilibrium position. This approach is in contrast to spring mechanism designs unable to actively control the spring rate independent of deflection, and with potential applications in various types of suspension and assembly systems. Results indicate that two direct drive brush-type direct current motors are required to drive the redundantly actuated mechanism …
A Simple Approach For Synthesis, Characterization And Bioactivity Of Bovine Bones To Fabricate The Polyurethane Nanofiber Containing Hydroxyapatite Nanoparticles, Faheem A. Sheikh, M. A. Kanjwal, Javier Macossay-Torres, N. A. M. Barakat, H. Y. Kim
A Simple Approach For Synthesis, Characterization And Bioactivity Of Bovine Bones To Fabricate The Polyurethane Nanofiber Containing Hydroxyapatite Nanoparticles, Faheem A. Sheikh, M. A. Kanjwal, Javier Macossay-Torres, N. A. M. Barakat, H. Y. Kim
Chemistry Faculty Publications and Presentations
In the present study, we had introduced polyurethane (PU) nanofibers that contain hydroxyapatite (HAp) nanoparticles (NPs) as a result of an electrospinning process. A simple method that does not depend on additional foreign chemicals had been employed to synthesize HAp NPs through the calcination of bovine bones. Typically, a colloidal gel consisting of HAp/PU had been electrospun to form nanofibers. In this communication, physiochemical aspects of prepared nanofibers were characterized by FE-SEM, TEM and TEM-EDS, which confirmed that nanofibers were well-oriented and good dispersion of HAp NPs, over the prepared nanofibers. Parameters, affecting the utilization of the prepared nanofibers in …
Electrospun Carbon Nanofibers Decorated With Various Amounts Of Electrochemically-Inert Nickel Nanoparticles For Use As High-Performance Energy Storage Materials, Liwen Ji, Zhan Lin, Mataz Alcoutlabi, Ozan Toprakci, Yingfang Yao, Guanjie Xu, Shuli Li, Xiangwu Zhang
Electrospun Carbon Nanofibers Decorated With Various Amounts Of Electrochemically-Inert Nickel Nanoparticles For Use As High-Performance Energy Storage Materials, Liwen Ji, Zhan Lin, Mataz Alcoutlabi, Ozan Toprakci, Yingfang Yao, Guanjie Xu, Shuli Li, Xiangwu Zhang
Mechanical Engineering Faculty Publications and Presentations
Carbon nanofibers decorated with various amounts of electrochemically-inert metallic nickel nanoparticles are synthesized through electrospinning and carbonization processes. The morphology and composition of Ni nanoparticles in carbon nanofibers are controlled by preparing different nanofiber precursors. The lithium-ion battery performance evaluations indicated that the content of electrochemically-inert Ni nanoparticles in carbon nanofibers has a great influence on the final electrochemical performance. For example, at certain Ni contents, these composite nanofibers display excellent electrochemical performance, such as high reversible capacities, good capacity retention, and excellent rate performance, when directly used as binder-free anodes for rechargeable lithium-ion batteries. However, when the Ni content …