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Full-Text Articles in Engineering

The Effects Of Surface Pace In Baseball, Jason Farlow May 2018

The Effects Of Surface Pace In Baseball, Jason Farlow

Senior Theses

A baseball travels across different surfaces at different paces. The goal of this experiment is to find a percentage difference in speeds the ball will reflect off a given surface. The energy lost on the turf surface was far more significant than on dirt surface as the turf lost an average of 26% of its energy as compared to just 16% of the energy on dirt. In the Northwest conference, teams play on four turf-based infields and five dirt-based infields. The results of this study suggest that kinetic friction forces are more significant in reducing ball rebound speed than in …


Design Of A Multidirectional Wear Testing Device For Simulating Wear Of Biocompatible Materials Used In Joint Implants, Carlos A. Rodriguez Betancourth May 2018

Design Of A Multidirectional Wear Testing Device For Simulating Wear Of Biocompatible Materials Used In Joint Implants, Carlos A. Rodriguez Betancourth

Theses and Dissertations

In the present work, a novel multidirectional pin-on-disc wear testing device designated CNC-POD (computer-numerical-control pin-on-disc) capable of replicating the cross-shear motions experienced by a prosthesis in vivo was designed and developed in the UTRGV in order to evaluate the wear resistance of new biomaterials. The CNC-POD consists of six temperature-controlled pin-on-disc stations mounted on a two-axis CNC table (X-Y). Each pin-on-disc station is load-programmable up to 510 Newtons (115 pounds). The CNC table allows the machine to reproduce a wide range of 2D patterns in millimeter scale on the six stations under a specific load. Friction force is measured during …


Manipulation And Automation Of Fbj Short-Axis Fasteners, Shane Forrest Wood Mar 2018

Manipulation And Automation Of Fbj Short-Axis Fasteners, Shane Forrest Wood

Theses and Dissertations

Legislative and market pressures are pushing automakers to achieve new fuel economy requirements in the coming years. To help achieve these goals automakers are reducing the overall weight of the vehicle by increasing the use of high-strength aluminum and advanced high-strength steels, and with this increased use comes the desire to quickly, and securely, join these materials within the vehicle. Friction bit joining is a process that lends itself well to joining these materials. This process uses consumable fasteners that need to be used in an automated production line. The geometry of these fasteners causes two main problems: the bits …


A Constitutive Model For Entangled Polydisperse Linear Flexible Polymers With Entanglement Dynamics And A Configuration Dependent Friction Coefficient. Part I: Model Derivation, David W. Mead, Saman Monjezi, Joontaek Park Jan 2018

A Constitutive Model For Entangled Polydisperse Linear Flexible Polymers With Entanglement Dynamics And A Configuration Dependent Friction Coefficient. Part I: Model Derivation, David W. Mead, Saman Monjezi, Joontaek Park

Chemical and Biochemical Engineering Faculty Research & Creative Works

A new polydisperse "toy" constitutive model is derived and developed from fundamental principles and ideas governing the nonlinear rheology of linear flexible polymers [Mead et al., J. Rheol. 59, 335-363 (2015)]. Specifically, the new model is comprised of four fundamental pieces. First, the model contains a simple differential description of the entanglement dynamics of discrete entanglement pairs. Second, the model contains a differential description of the ij entanglement pair orientation tensor dynamics. Third, following a similar development by Mead and Mishler [J. Non-Newtonian Fluid Mech. 197, 61-79 and 80-90 (2013).], a diluted stretch tube is constructed to describe the relative …


A Constitutive Model For Entangled Polydisperse Linear Flexible Polymers With Entanglement Dynamics And A Configuration Dependent Friction Coefficient. Part Ii. Modeling "Shear Modification" Following Cessation Of Fast Shear Flows, David W. Mead, Saman Monjezi, Joontaek Park Jan 2018

A Constitutive Model For Entangled Polydisperse Linear Flexible Polymers With Entanglement Dynamics And A Configuration Dependent Friction Coefficient. Part Ii. Modeling "Shear Modification" Following Cessation Of Fast Shear Flows, David W. Mead, Saman Monjezi, Joontaek Park

Chemical and Biochemical Engineering Faculty Research & Creative Works

The polydisperse Mead-Park (MP) "toy" molecular constitutive model developed in Paper I [Mead et al., J. Rheol. 62, 121-134 (2017)] as well as our previously published work [e.g., J. Rheol. 59, 335-363 (2015)] is used in the "forward" direction to study model polydisperse melts of entangled linear flexible polymers in severe, fast shear flows. The properties of our new model are elucidated by way of numerical simulation of a representative model polydisperse polymer melt in step shear rate and interrupted shear flow. In particular, we demonstrate how the MP model simulates the individual molecular weight distribution (MWD) component dynamics as …