Engineering Commons^™

Experimental Study Of Condensation In Different 3d Printed Regenerators In A Thermoacoustic Cooler, Aibek Bekkulov

Theses and Dissertations

Thermoacoustics (TA) deals with the conversion of heat into sound and vice versa. Device that converts heat into acoustic work is called TA heat engine, while the device that transfers energy from a low temperature reservoir to a high temperature one by utilizing acoustic work is called TA cooler. A simple construction of TA cooler includes an acoustic speaker, a resonator tube and a regenerator stack in which the temperature gradient is being imposed. Such a TA cooler has several advantages over traditional compression/expansion cooling machine such as its simplicity of the construction, high reliability and lack of toxic refrigerants. …

Biomechanics Of Lower Limb During The Golf Swing Using Opensim Modeling, Andrew B. Butler

Theses and Dissertations

The purpose of this research is to investigate the biomechanics of the lower-limb using an inverse dynamics model. Experimental data, recorded by an integrated Motion Analysis – Force Plate System in the UTRGV Biomechanics Laboratory, is used to determine ground reaction forces and marker trajectories. OpenSim, a graphical musculoskeletal and computational platform, is used to model the body in three dimensions. The human body is modeled as a 12-segment linkage, consisting of 23 degrees-of-freedom and 92 muscles. The experimental data for the Biomechanics Laboratory is imported in OpenSim. Then, joint angles, generalized coordinates & accelerations of lower-limb segments, muscle forces, …

Security Assessment Of Select Computer Systems Under Distributed Denial Of Service Attacks Performed By Botnets, Hugo Armando Herrera Martinez

Theses and Dissertations

With the passage of time Internet connectivity has been found on more electronic devices than in previous decades. This continuous development may be perceived as a double-edged sword. While the world becomes more Internet-connected and quality of life increases, the lack of proper security protocols in some of these electronic devices permits illegitimate parties to take control of them for their own malicious purposes.

This thesis studies the impact of compromised Internet-connected devices on commonly used server operating systems: Microsoft’s Windows Server 2012 R2 Datacenter, Windows Server 2016 Datacenter, and Apple’s macOS 10.13.6 High Sierra deployed on Apple’s Mac Pro …

Development Of Flexible Photo-Mechanoluminescent Polymeric Based Systems, Carlos Hernandez

Theses and Dissertations

The project focuses on the creation of nanofiber systems with enhanced photo-mechanoluminescent response and high mechanical flexibility to further enhance promising optical applications. Lanthanide-Polyvinyl Di-Fluoride fiber systems were created using centrifugal spinning and characterized using SEM, FTIR, XPS, DSC, XRD, and PL. Fibers luminescence response was gotten when induced by ultraviolet light and the application of an impact force.

Polymeric Pvdf Fibers For Piezoelectric Applications In Energy Harvesting, Misael E. Martinez

Theses and Dissertations

This work focuses on developing and characterizing the piezoelectric response of Cerium doped Polyvinylidene Fluoride (PVDF) fine fibers and the effects of dopants and alignment on the formation of the β-phase and consequently on the piezoelectric performance. Six sets of fiber mats were prepared varying the concentration (2.5–7.5wt%) of Cerium (III) Nitrate-Hexahydrate and Ammonium-Cerium (IV) Sulfate-Dihydrate. Fiber mats were developed using the Forcespinning® technique and the angular velocity and dopant concentration were adjusted to obtain a synergy between fiber yield and fiber diameter. Fourier Transform Infrared Spectroscopy showed a significant enhancement in the PVDF β-phase and inhibition of the non-polar …

Dehumidification Water Quality Analysis Of The South Texas Gulf Of Mexico, Erik Esteban Castillo

Theses and Dissertations

This project is to introduce a new methodology for environmental research that analyzes humidity from a water treatment perspective. This is done by using a household dehumidifier, which extracts the excess humidity in a given space, to harvest the samples. The dehumidifier was used outside to act as an Atmospheric Water Generator (AWG), which is the process of extracting water from the atmosphere. When AWG is placed near shoreline, then it's classified as a Desalinated Atmospheric Water Generator (DAWG) since it extracts distilled seawater water-vapors. The methodology for DAWG analyzed turbidity in the humidity on SPI, indicating to meet {<.15} TCEQ turbidity water quality standard. The turbidity also showed to have an adverse relation to weather conditions. There is an open market in research on this topic, where the methodology for DAWG can offer answers. This project identifies DAWG as being a sustainable source of potable water for a municipality.

Secondary Resonances Of Electrostatically Actuated Mems Cantilevers, Christopher I. Reyes

Theses and Dissertations

In this work the behavior of micro-electromechanical (MEMS) cantilever resonators is investigated. The cantilever resonators are electrostatically actuated with hard AC voltage resulting in nine distinct resonances cases including super and subharmonic resonances. The amplitude frequency and amplitude voltage bifurcation diagrams are obtained for each of the nine resonance cases. Reduced order models (ROMs) are developed to include one and two modes of vibration. Three different methods are used to solve the ROMs namely 1) the method of multiple scales (MMS), which is a perturbation method used for one mode of vibration, 2) the homotopy analysis method (HAM), which is …

An Evaluation Of Wastewater Pumping Station Facilities Using Statistical Techniques In Analyzing Each For Rehabilitation Design And To Improve The Adverse Environmental Affects, Zenaida S. Guerrero

Theses and Dissertations

The objective of this research project is to develop two evaluation models, one using excel to provide a design criterion for wastewater pumping stations in collecting design parameters and information effecting efficiency and performance of the pumps. Secondly, to develop a linear regression model for these parameters giving a correlation between dependent and independent variables to verify adverse environmental aspects. This study is based in the City of Weslaco, pertaining to the north waste watershed. The parameters collected are age, efficiency, service area, total dynamic head, existing conditions, monthly sanitary sewer over flow work orders, precipitation data, population by service …

Design Of A Bedside Walker-Cane Hybrid To Aid Senior Adults Avoid Falls During Night Walks, Jorge L. Gutierrez

Theses and Dissertations

The objective of this research and development work is to design a device to help senior adults prevent fall during night walks indoors. The problem of elders falling at a night setting was found to be caused by the multiple environmental and medical conditions. The target demographic was found to be seniors from age 65 and older. Several occupational therapists and two physical therapists were consulted to gain knowledge on elders' behavior, possible improvements on current existing devices, and feedback regarding the early prototype built. Several products and patents were researched with a lack of findings on similar products that …