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Articles 1 - 15 of 15
Full-Text Articles in Mechanical Engineering
A Preventive Maintenance Framework In Dairy Production Operations, Maria F. Vargas
A Preventive Maintenance Framework In Dairy Production Operations, Maria F. Vargas
Theses and Dissertations - UTB/UTPA
Dairy operations suffer frequent stops. Product shrinkage is a consequence of downtime, which includes losses of packaging material, scraped finish product and capacity. This work proposes a troubleshooting methodology to identify causes of downtime, estimation of waste cost, and minimization of operation disruptions by applying a combination of a cost function to assess waste, and performance measurements. The drinkable yogurt process is evaluated to find the principal areas for wasted bottles and yogurt. In order to make a decision about which of those sources to address, a General Cost Function is used to estimate waste cost which include measurements that …
Low Speed Water Tunnel Testing, John J. Taylor
Low Speed Water Tunnel Testing, John J. Taylor
Theses and Dissertations - UTB/UTPA
Water tunnels are ideal for studying flow patterns for hydrodynamic effects. The functionality of the University of Texas-Pan American water tunnel was limited by not being able to measure forces and moments corresponding to flow patterns. This report delivers an experimental set-up for calibrating the velocity of the water and development of a load measuring system to relate simultaneous visual investigation. An in-depth parts breakdown of the SST-model pump and the dye injection system for flow visualization will be reviewed. Few balances have been made for water tunnels due to small and difficult to measure flow-induced forces. The motive is …
Effects Of Vapor Grown Carbon Nanofibers On Electrical And Mechanical Properties Of A Thermoplastic Elastomer, Daniel Thomas Basaldua
Effects Of Vapor Grown Carbon Nanofibers On Electrical And Mechanical Properties Of A Thermoplastic Elastomer, Daniel Thomas Basaldua
Theses and Dissertations - UTB/UTPA
Carbon nanofiber (CNF) reinforced composites are exceptional materials that exhibit superior properties compared to conventional composites. This paper presents the development of a vapor grown carbon nanofiber (VGCNF) thermoplastic polyurethane (TPU) composite by a melt mixing process. Dispersion and distribution of CNFs inside the TPU matrix were examined through scanning electron microscopy to determine homogeneity. The composite material underwent durometer, thermal gravimetric analysis, differential scanning calorimetry, heat transfer, hysteresis, dynamic modulus, creep, tensile, abrasion, and electrical conductivity testing to characterize its properties and predict behavior. The motivation for this research is to develop an elastomer pad that is an electrically …
Fabrication And Characterization Of Silver- And Copper-Coated Nylon 6 Forcespun Nanofibers By Thermal Evaporation, Dorina M. Mihut, Karen Lozano, Heinrich D. Foltz
Fabrication And Characterization Of Silver- And Copper-Coated Nylon 6 Forcespun Nanofibers By Thermal Evaporation, Dorina M. Mihut, Karen Lozano, Heinrich D. Foltz
Mechanical Engineering Faculty Publications and Presentations
Silver and copper nanoparticles were deposited as thin films onto substrates consisting of Nylon 6 nanofibers manufactured using forcespinningR equipment. Different rotational speeds were used to obtain continuous nanofibers of various diameters arranged as nonwoven mats. The Nylon 6 nanofibers were collected as successive layers on frames, and a high-vacuum thermal evaporation method was used to deposit the silver and copper thin films on the nanofibers. The structures were investigated using scanning electron microscopy–scanning transmission electron microscopy, atomic force microscopy, x-ray diffraction, and electrical resistance measurements. The results indicate that evaporated silver and copper nanoparticles were successfully deposited on Nylon …
Long-Lasting Effect Of Initial Configuration In Gravitational Spreading Of Material Fronts, Nadim Zgheib, Thomas Bonometti, S. Balachandar
Long-Lasting Effect Of Initial Configuration In Gravitational Spreading Of Material Fronts, Nadim Zgheib, Thomas Bonometti, S. Balachandar
Mechanical Engineering Faculty Publications and Presentations
We present the results from laboratory experiments and fully resolved simulations pertaining to finite-release turbulent density flows with a non-axisymmetric initial shape. First, we demonstrate that the effects of the initial shape influence the current’s evolution well into the long-time phase which would corresponds to the inertial self-similar phase in the case of planar or axisymmetric configurations. Then, we identify the physical mechanisms responsible for this dependence and propose a new model capable of capturing the dynamics of such releases. Finally, we show that this dependence on the initial configuration is robust for various types of gravity currents over a …
A Decision Support Model For Process Planning In Remanufacturing Using Fuzzy Set Theory And Genetic Algorithm, Juan C. Martinez
A Decision Support Model For Process Planning In Remanufacturing Using Fuzzy Set Theory And Genetic Algorithm, Juan C. Martinez
Theses and Dissertations - UTB/UTPA
The environmental awareness and resources preservation has boosted the use of remanufacturing processes. Many important studies have been made in this area, but there are still pitfalls and opportunities that have not been explored yet. Specifically, the cleaning processes play a critical role in remanufacturing. It is among the top of most costly processes and it plays a key step in remanufacturing because delivers a free of contaminant product ready for reprocessing. Understanding and selecting the best processes to meet the need and goals of remanufacturers are important for effective and efficient remanufacturing. Due to variables and high uncertainty associated …
A Study Comparing The Pedagogical Effectiveness Of Virtual Worlds And Of Traditional Training Methods, Benjamin Peters
A Study Comparing The Pedagogical Effectiveness Of Virtual Worlds And Of Traditional Training Methods, Benjamin Peters
Theses and Dissertations - UTB/UTPA
This experiment tests whether a virtual world is a more suitable alternative to classical paper and pen case studies for teaching people how to disarm improvised explosive devices (IED). Following preliminary training, the subjects are separated into a group of 32 and one of 33. The odd-numbered subjects receive case studies while the even-numbered subjects receive training in the virtual world, Second Life. After their training, each subject is put into a simulated test where they attempt to properly disarm a mock IED attached to a victim played by an actor/actress. The results of the experiment show no significant difference …
Creating A Seamless Pipeline Into Undergraduate Programs In Stem Fields Through Region-Wide Articulation Agreements, Immanuel Edinbarough, Mikhail M. Bouniaev, Bill W. Elliott
Creating A Seamless Pipeline Into Undergraduate Programs In Stem Fields Through Region-Wide Articulation Agreements, Immanuel Edinbarough, Mikhail M. Bouniaev, Bill W. Elliott
Manufacturing & Industrial Engineering Faculty Publications and Presentations
Underrepresented minority students pursue science, technology, engineering, and mathematics (STEM) related degrees at much lower rates compared to other segments of the population. To attract minority students, schools with STEM programs have resorted to myriad strategies such as cohorts, scholarships, mentoring, summer bridges, etc. Some schools have also sought innovative ways to develop a pipeline for graduates of two-year technical degree programs to matriculate into their four-year STEM programs and complete the remaining coursework leading to a BAT or BS degree. The University of Texas at Brownsville (UTB) has adopted this latter innovative approach to increasing student enrollment in STEM …
A Decision Support System To Measure Product Suitability For Additive Manufacturing Processes, Cynthia De Vasconcellos Barros
A Decision Support System To Measure Product Suitability For Additive Manufacturing Processes, Cynthia De Vasconcellos Barros
Theses and Dissertations - UTB/UTPA
Additive Manufacturing (AM) technologies started arising around 1980’s and they are currently considered to be the third industrial revolution. With improvements in computers, materials, and automated machines, manufacturers across several types of industries are becoming more familiar with AM processes, and it has become more common to see products that are being fabricated by using this new technology. However, there are still questions regarding when it is suitable to use Additive Manufacturing or conventional manufacturing processes depending on different factors. The purpose of this thesis is to create a Decision Support System (DSS) that will help users measure product suitability …
Nanostructured Transition Metal Oxides For Energy Storage And Conversion, Qiang Li
Nanostructured Transition Metal Oxides For Energy Storage And Conversion, Qiang Li
Theses and Dissertations - UTB/UTPA
The conventional film configuration of electrochemical electrodes hardly fulfills the high energy and efficiency requirements because heavy electroactive material deposition restricts ion diffusion path, and lowers power density and fault tolerance. In this thesis, I demonstrate that novel nanoarchitectured transition metal oxides (TMOs), e.g. MnO2, V2O5, and ZnO, and their relevant nanocomposites were designed, fabricated and assembled into devices to deliver superior electrochemical performances such as high energy and power densities, and rate capacity. These improvements could be attributed to the significant enhancement of surface area, shortened ion diffusion distances and facile penetration of electrolyte solution into open structures of …
Corrosion Assessment And Enhanced Biocompatibility Analysis Of Biodegradable Magnesium-Based Alloys, Luis Enrique Pompa
Corrosion Assessment And Enhanced Biocompatibility Analysis Of Biodegradable Magnesium-Based Alloys, Luis Enrique Pompa
Theses and Dissertations - UTB/UTPA
Magnesium alloys have raised immense interest to many researchers because of its evolution as a new third generation material. Due to their biocompatibility, density, and mechanical properties, magnesium alloys are frequently reported as prospective biodegradable implant materials. Moreover, magnesium based alloys experience a natural phenomena to biodegrade in aqueous solutions due to its corrosive activity, which is excellent for orthopedic and cardiovascular applications. However, major concerns with such alloys are fast and non-uniform corrosion degradation. Controlling the degradation rate in the physiological environment determines the success of an implant. In this investigation, three grades of magnesium alloys: AZ31B, AZ91E and …
Manufacture And Characterization Of Silver And Copper Nanostructures Produced Via Forcespun Nylon 6 Nanofibers, Wenqian Zhao
Manufacture And Characterization Of Silver And Copper Nanostructures Produced Via Forcespun Nylon 6 Nanofibers, Wenqian Zhao
Theses and Dissertations - UTB/UTPA
Nylon 6 nanofibers were produced using the Forcespinning® method and were deposited with silver or copper thin films using the high vacuum thermal evaporation technique for surface functionalization of nanostructures. The changes in surface composition, morphology and surface energy of native and metallic coated Nylon 6 nanofibers were examined. Their antibacterial properties of native, silver or copper coated Nylon 6 nanofibers were tested. Furthermore, the Nylon 6 nanofibers were used as templates in order to obtain silver or copper nanotubes where the polymer was removed after high temperature calcination. The metallic coated Nylon 6 nanofibers and metallic nanotubes morphology and …
Influence Of Surface Modification On Corrosion And Biocompatibility Of Titanium Alloys, Zia Ur Rahman
Influence Of Surface Modification On Corrosion And Biocompatibility Of Titanium Alloys, Zia Ur Rahman
Theses and Dissertations - UTB/UTPA
Titanium alloys enhance the quality and longevity of human life by replacing or treating various parts of the body. However, the aggressive body fluids lead to corrosion and metal ions dissolution. These ions leach to the adjacent tissues and causes adverse reactions. Surface modifications improve corrosion resistance and biological activity. In this investigation, electropolishing, magnetoelectropolishing, titanium coating and hydroxyapatite coating were carried out on commercially pure titanium (CPTi), Ti6Al4V and Ti6Al4V-ELI (Extra Low Interstitials). These surface modifications are known to affect surface chemistry, morphology, wettability, corrosion resistance and biocompatibility of these materials. In vitro cyclic potentiodynamic polarization tests were conducted …
Bifurcation Type Change Of Ac Electrostatically Actuated Mems Resonators Due To Dc Bias, Dumitru Caruntu, Kyle N. Taylor
Bifurcation Type Change Of Ac Electrostatically Actuated Mems Resonators Due To Dc Bias, Dumitru Caruntu, Kyle N. Taylor
Mechanical Engineering Faculty Publications and Presentations
This paper investigates the nonlinear response of microelectromechanical system (MEMS) cantilever resonator electrostatically actuated by applying a soft alternating current (AC) voltage and an even softer direct current (DC) voltage between the resonators and a parallel fixed ground plate. The AC frequency is near natural frequency. This drives the resonator into nonlinear parametric resonance. The method ofmultiple scales (MMS) is used to solve the dimensionless differential equation of motion of the resonator and find the steady-state solutions.The reduced order model (ROM) method is used to validate the results obtained using MMS. The effect of the soft DC voltage (bias) component …
Unidirectional Rotary Tendency Of A Wave-Driven Rotor, Yingchen Yang
Unidirectional Rotary Tendency Of A Wave-Driven Rotor, Yingchen Yang
Mechanical Engineering Faculty Publications and Presentations
Ocean waves can directly drive WECs (wave energy converters) to perform two types of motion—reciprocating motion and unidirectional rotary motion. In general, the efficiency of a reciprocating WEC is strongly wave-frequency dependent, whereas the efficiency of a rotary WEC can be somewhat wave-frequency independent. To date, a huge majority of WEC technologies under development in industry belong to the reciprocating class, and only a few WEC concepts fall in the unidirectional rotary class. In the present work, a wave-driven rotor for unidirectional rotary motion was proposed and characterized. A numerical tool has been developed for characterization of the rotor’s unidirectional …