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Articles 1 - 13 of 13
Full-Text Articles in Mechanical 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 …
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 …
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 …