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Full-Text Articles in Mechanical Engineering
Mass Production Of Β-Silicon Carbide Nanofibers By The Novel Method Of Forcespinning, Alfonso Salinas
Mass Production Of Β-Silicon Carbide Nanofibers By The Novel Method Of Forcespinning, Alfonso Salinas
Theses and Dissertations - UTB/UTPA
Non-oxide Ceramics such as silicon carbide have very unique properties, for example high toughness, thermal stability, wear resistant, and thermal shock resistance these properties make these ceramic fibers excellent for high temperature applications. Here we present the development of Silicon Carbide nanofibers utilizing a Polystyrene/Polycarbomethylsilane solution as the precursor materials. The Forcespinning ® was performed under a controlled nitrogen environment to prevent fiber oxidation. Characterization was conducted using scanning electron microscopy, x-ray diffraction, and thermogravimetric analysis. The results show successful formation of high yield, long continuous bead-free nanofibers with diameters ranging from 280nm to 2 micron depending on the selected …
Thermal Analysis Of Carbon Nanofiber Reinforced Isotactic Polypropylene, Anna Alicia Hernandez
Thermal Analysis Of Carbon Nanofiber Reinforced Isotactic Polypropylene, Anna Alicia Hernandez
Theses and Dissertations - UTB/UTPA
Isotactic Polypropylene (IPP) is a commonly known thermoplastic that has unique properties include being light weight, high performance, impact strength, tensile strength, elongation, and high temperature properties. The use of vapor grown carbon nanofiber (VGCNF) reinforcements on polypropylene has shown to produce high specific modulus, strength, electrical and thermal properties on specimens. Thermogravimetric (TGA) investigations on the thermal degradation of isotactic polypropylene – vapor grown carbon nanofibers composites in nitrogen were reported. The mass evolution as a function of temperature is a single sigmoid for both polypropylene and polypropylene loaded with VGCNF. The inflection temperature of these sigmoids increases as …
Design And Optimization Of A Railroad Conductive Suspension Element Pad Composed Of Thermoplastic Polyurethane And Carbon Black, Ruben Suarez Jr.
Design And Optimization Of A Railroad Conductive Suspension Element Pad Composed Of Thermoplastic Polyurethane And Carbon Black, Ruben Suarez Jr.
Theses and Dissertations - UTB/UTPA
The AdapterPlus™ Pad, made from thermoplastic polyurethane (TPU), is used to enhance steering and prevent metal-to-metal contact between the railcar side frame and the bearing adapter. Although the AdapterPlus™ Pad acts as a pedestal liner in the suspension assembly, it must allow electric current to flow from the rail, through the bearing adapter wall to the side frame in order to activate a solenoid air valve that releases cargo gates. Currently, the pad uses copper inserts that allow current through. Because the Adapter Plus™ Pad is subject to large dynamic loads, the copper inserts permanently deform losing contact and cutting …
Nonlinear Dynamics Of Carbon Nanotubes Under Soft Alternating Current Actuation, Le Luo
Nonlinear Dynamics Of Carbon Nanotubes Under Soft Alternating Current Actuation, Le Luo
Theses and Dissertations - UTB/UTPA
This thesis work deals with electrostatically actuated Carbon Nanotubes (CNTs) cantilevers. Four forces are acting on the CNTs cantilever, namely damping, elastic, electrostatic and van der Waals forces. The van der Waals force is significant for values of 50 nm or lower of the gap between the CNTs and the ground substrate. As both electrostatic and van der Waals forces are nonlinear, and the CNTs electrostatic actuation is given by alternating current (AC) voltage, the CNTs undergo nonlinear parametric dynamics. The Method of Multiple Scales (MMS) and Reduced Order Model (ROM) are employed to investigate the system under soft excitation …
Development Of Hydrodynamic Channel Routing Model Of The Lower Rio Grande River To Assist In Flood And Stormwater Management, Andrew W. Leeper
Development Of Hydrodynamic Channel Routing Model Of The Lower Rio Grande River To Assist In Flood And Stormwater Management, Andrew W. Leeper
Theses and Dissertations - UTB/UTPA
Flooding and stormwater management of the Lower Rio Grande River (LRG) has become a major issue throughout the years with local entities along the river. The purpose of this study is to develop a hydrodynamic channel routing model to predict water surface elevation changes due to flooding. The study area consists of the LRG from Los Ebanos to Brownsville, Texas. This hydrodynamic model displays the hydraulics of the water flow through the LRG and determines where potential flood hazards exist. To verify the accuracy of the model a series of calculated output hydrographs were established at the Progreso Bridge and …
Calibration And Optimization Of A Load Sensor Embedded In A Railroad Bearing Adapter, Lorenzo Saenz Iv
Calibration And Optimization Of A Load Sensor Embedded In A Railroad Bearing Adapter, Lorenzo Saenz Iv
Theses and Dissertations - UTB/UTPA
Freight railcars rely heavily on weigh bridges and stations to determine cargo load. As a consequence, all load measurements are limited to certain locations and specified prices. To this end, this study presents work performed to develop one of the first economical, reliable sensors for keeping track of both dynamic and static loads on a freight railcar. Preliminary testing provided a strain-gauge based sensor that delivered load information in the laboratory environment. Federal Railroad Association (FRA) protocol testing was met and consistent results were obtained from the sensing device. The latter allowed for an optimized sensor that could potentially deliver …
Proper Orthogonal Decomposition Of High-Speed Flows, Oscar Huerta
Proper Orthogonal Decomposition Of High-Speed Flows, Oscar Huerta
Theses and Dissertations - UTB/UTPA
In an effort to understand physical characteristics of high speed flows such as an Impinging Jet (Mach 1.5) and Pulsed Jet (Mach 0.3) both propulsions systems are investigated from phased-locked Particle Image Velocimetry (PIV) data that is analyzed using Proper Orthogonal Decomposition (POD). The purpose of POD is to extract the most dominant features found in the flow. The method calculates the eigenvalues and the spatial eigenfunctions that are related to the total kinetic energy with only a few basis functions. Results for an Impinging Jet show about 70% of the energy in the first twenty modes that represent the …