Mechanical Engineering Commons^™

The Implementation And Comparison Of Fuzzy Logic Control Systems To Modern Control Methods On Low-Cost Hardware, Cristian A. Barron

Theses and Dissertations

Modern control engineering provides many options to automate systems for which a mathematical model is required. Another control does not rely on the mathematical model of the system and is known as fuzzy logic control. In this study, a literature review is conducted on existing control systems strategies such as proportional integral and derivative (PID), linear quadratic regulator (LQR), and fuzzy logic controller (FLC), the complexity of the systems they control, and their strengths and weaknesses. In addition, a series of experiments are conducted, both through simulations in MATLAB Simulink and using their implementation using the actual physical hardware to …

Optimizing A Railroad Bearing Condition-Monitoring Algorithm For Use With An Onboard Wireless Low-Power Sensor Module, Jonas Regan Leano Cuanang

Theses and Dissertations

An algorithm that utilizes vibration measurements was developed by the UTRGV Center for Railway Safety to monitor the condition of railroad bearings. This algorithm uses the data collected from accelerometers on the bearing adapters to determine if there is a defect, where the defect is within the bearing, and the approximate size of the defect. Laboratory testing was performed on the UTCRS single bearing test rig. A four-second sample window of the recorded vibration data is used by the algorithm to reliably identify the defective component inside the bearing with up to a 100% confidence level. However, considerable computational power …

The Optimization Of Efficiency And Infrastructure For Modern Potable Water Treatment Plants, Brent A. Dekock

Theses and Dissertations

The USDOE Industrial Assessment Centers (IACs) is a program that is designed to help small and medium-sized manufacturing facilities reduce their overall costs and improve energy efficiency. This includes improving potable water treatment plants which supply water throughout the country. This thesis covers the process of how IAC branches and water treatment facilities generally operate, as well as several assessment recommendations that have been developed by a branch of the IAC for several water treatment plants based in the Rio Grande Valley of Texas. The steps of the assessment and water treatment process are described, and several cost saving measures …

Effect Of Adding Palm Fiber To Thermal Conductivity Of Quick Set Concrete, Monica Garcia

Theses and Dissertations

As climate change becomes a more dire issue and more readily accepted by those in power, the demand for local and systemic solutions grows louder. In urban environments, one issue of concern is the contribution of anthropogenic heat from buildings which contributes to localized warming of the environment. A method that can reduce anthropogenic heat is decreasing the thermal conductivity of building materials. The objective of this study is to examine the possibility of using palm fibers to reduce the thermal conductivity of quick-set concrete samples. The data gathered in this study are used to determine the thermal conductivity value …

The Design, Fabrication, And Testing Of A Cooling Garment, Richard James Garza

Theses and Dissertations

The aim of this research is to design a device or technology capable of cooling the user – such as a college student walking to class, for example – in a manner as convenient as putting on a jacket. The idea is to use the peltier effect – a phenomenon in which two dissimilar semi-conductors heat up and cool down with the application of an electric current – as the source of heat absorption used to cool the user. In this research it will be determined whether or not it is feasible to use such a phenomenon to keep the …

Assessing The Performance Of Reconditioned Railroad Tapered-Roller Bearings Used In Freight Rail Service, Veronica Valeria Hernandez

Theses and Dissertations

The rail industry currently utilizes two wayside detection systems to monitor the health of freight railcar bearings in service: The Trackside Acoustic Detection System (TADS™) and the wayside Hot-Box Detector (HBD). Bearings that are removed from service are sent to specialized facilities where they undergo a reconditioning process before the bearings can be returned to rail service. The reconditioning process has been used for decades although there has been no previous study on the effectiveness of the reconditioning process on defective bearings that were removed from service. This persuaded the researchers from the University Transportation Center for Railway Safety (UTRCS) …

Optimizing Energy Power Consumption Of Freight Railroad Bearings Using Experimental Data, Carlos Eliasar Lopez Iii

Theses and Dissertations

Throughout the railway industry, trains use systems that record total energy efficiency of a train but not energy efficiency or consumption by components. Monitoring freight bearing power consumption can support the railroad industry efforts to maintain the railroad economic competitiveness and minimize the environmental impact.

For more than a decade now, the University Transportation Center for Railway Safety (UTCRS) at the University of Texas Rio Grande Valley (UTRGV) has been collecting power consumption data for railroad bearings under various loads, speeds, ambient temperatures, bearing condition, and bearing classes. Specifically, data such as temperatures, voltages, speed, and load were collected to …

Electromagnetic Interference Shielding Effectiveness Of Interlayered Systems Containing Metal-Oxide, Conducting Polymer And Carbon Nanotube Reinforced Polymeric Composites, Shaik Merkatur Hakim Marjuban

Theses and Dissertations

The Electromagnetic Interference (EMI) Shielding Effectiveness (SE) has become one of the important requirements for the devices associated with telecommunication systems consisting of large frequency bands. The degradation of the quality of transmitting signal influenced by frequencies emitting from external sources can be reduced by covering the circuits of the devices by EMI Shielding materials like polymer composites, metal-based nanofiber mats, the metal of oxide films, etc. The investigation strives for the attenuation of EMI by introducing two composite mats from conducting polymer-based, multiwalled carbon nanotubes (MWCNTs) coated Nylon 6 nanofiber composites. Two other composite mats are also developed by …

Water-Soluble Polymers With Ceramic/Metal Nanoparticles For Use As Anode Materials In Lithium-Ion And Sodium-Ion Batteries, Roberto Orrostieta Chavez

Theses and Dissertations

Aqueous solutions of poly(vinylpyrrolidone) (PVP) with 20, 25, and 28 wt.% concentrations were successfully spun into fibers by centrifugal spinning. The pristine PVP fibers were annealed and carbonized to produce flexible carbon fibers for use as binder-free anodes in lithium-ion and sodium-ion batteries. These flexible carbon fibers were prepared by developing a novel three-step heat treatment to reduce the residual stresses in the pristine PVP precursor fibers and to prevent fiber degradation during carbonization. The average diameters of the pristine, annealed, and carbonized fibers were obtained using scanning electron microscopy (SEM), which showed that the average diameter of the carbon …

Mono And Multi-Objective Optimization And Modeling Of Machining Performance In Face Milling Of Ti6al4v Alloy, Al Mazedur Rahman

Theses and Dissertations

Titanium alloys are extensively used in numerous industries like aerospace, automotive, military, etc., due to their exclusive characteristics. But machining these alloys has always been challenging for manufacturers. This research investigates the effect of radial depth of cut on cutting forces, tool life, surface roughness (Ra), and material removal rate (MRR) during face milling of Ti6Al4V alloy. It also aims to perform mono and multi-objective optimization of response characteristics to determine the optimal input parameters, namely cutting speed, feed rate, and radial depth of cut. Taguchi method and analysis of variance (ANOVA) have been used for mono-objective optimization, whereas Taguchi-based …

Development Of Plant Extract-Based Composite Fibers And Aerogels, Raul C. Barbosa

Theses and Dissertations

The aim of this study is to use the solid templating process of pullulan nanofibers in order to produce biocompatible, biodegradable, and antibacterial aerogels. The developed aerogels were produced using cross-linked pullulan nanofibers, which provide a water-stable structure allowing them to be used as wound dressing material. The morphology, thermal properties, water solubility, and thermal and physical properties of the nanofibers and aerogels were characterized. Furthermore, the antibacterial effect against gram-negative bacteria, Escherichia coli, and the biocompatibility using mouse embryonic fibroblasts (NIH 3T3) were investigated.

Experimental Study Of Graphene Energy Absorbing Layer In Femtosecond Infrared Laser Assisted Bioprinting, Chaoran Dou

Theses and Dissertations

The bioprinting, as a new branch of additive manufacturing, already shown its potential in organ transplantation, medicine develop and personalized medicine. There are three types of bioprinting: droplet based bioprinting, extrusion based bioprinting and laser assisted bioprinting (LAB). Compared with other types of bioprinting, the LAB is the only bioprinting method that does not have a nozzle, which gives it the ability to print high viscosity bioink. The LAB also enjoys higher resolution and cell viability than other methods.

The bubble/jet formation process is the most important process for the LAB, which deposits the bioink to the substrate. To utilize …

An Experimental Thrust Measurement Study On The Nozzle Asymmetry Of Turbulent Pulsed Jets, Cesar Alberto Leos Jr.

Theses and Dissertations

The resurgence of pulsejet engines has renewed the interest of the flow characteristics responsible for the high levels of thrust augmentation that are necessary for Vertical/Short Take-Off and Landing (V/STOL) aircraft. It is well known that pulsation of the engine plays an important role on the thrust performance, but many of the characteristics that are primarily responsible for these enhancements are not well understood. This study is carried out to elucidate the effect of nozzle exit Mach number and the nozzle exit geometry on the characteristics of a high Reynolds number (~105), turbulent free pulsed jet.

Direct thrust measurements are …

Lead Free Piezoelectric And Triboelectric Energy Film For Energy Harvesting And Sensory Applications, Abu Musa Abdullah

Theses and Dissertations

In recent times, Triboelectricity and Piezoelectricity has been widely used for utilizing mechanical energy from ambient environment. Scientists are focusing towards developing advanced material composites for utilizing piezoelectricity and triboelectricity for energy harvesting and sensory applications. This work includes two projects regarding the application of lead free piezoelectric and triboelectric energy for energy harvesting and sensory applications. Human motion has been attributed as a source of mechanical energy to drive electronic devices and sensors through Triboelectric Nanogenerator (TENG). Based on the principles of single electrode TENG, we have developed a Triboelectricity based Stepping and Tapping Energy Case (TESTEC) which magnifies …

Implementation Of Cholesteric Liquid Crystals In Fibrous Based Membranes, Ydana Yanell Virgen Gracia

Theses and Dissertations

The project consists of an investigation of optical sensors. On this project, the main focus was to implement materials that had properties such as thermochromism, piezochromism, and be able to detect volatile organic compounds with a color change response. The materials selected for this project were Cholesteric Liquid Crystals (CLCs) in different combinations and ratios. There were also four different methods using Forcespinning © technology to apply the CLCs into a polymer matrix; these were, In-Solution, Dip Coating, Coaxial Spinning, and Emulsion. The best results were given by Dip Coating, but the method with the best viable solution was Coaxial …

Bio-Inspired Wings In High Freestream Turbulence: A Numerical And Experimental Study, Alexia Martinez Ibarra

Theses and Dissertations

The aerodynamics and flow field characteristics of a NACA 0010 airfoil with leading-edge modifications were investigated in flow with freestream turbulence intensity of 4%. A set of 4 airfoils, each of them with different wavelength (4, 8, 10, 12 tubercles along the spanwise direction) was experimentally studied. An unmodified NACA 0010 airfoil was used as baseline. The Reynolds number was varied from 201,200 to 351,600. The angle of attack was varied within the range of -6 to 20 degrees. Several techniques were used to investigate the characteristics of the airfoils such as wake profile surveys, 6-axis force measurements, and Particle …

Development Of Vegetable Oil Based Nano-Lubricants, Vicente Cortes

Theses and Dissertations

Nowadays, the depletion of crude oil reserves in the world and the global concern in protecting the environment from contamination have renewed interest in developing environment friendly lubricants derived from alternative sources such as vegetable oils. Mineral oil is the most common lubricant, however, it also has poor biodegradable properties. Vegetable oils exhibit good viscosity index, flash point, pour point, tribological properties, and are biodegradable. Furthermore, the use of nanoparticles as additives has shown to improve anti wear and anti-friction properties of the base lubricant. The present research project will evaluate experimentally the rheological and tribological behavior of coconut oil, …

Processing And Microstructural Characterization Of Silicon Carbide, Silicon Nitride, And Tungsten Carbide Fibers, Christian Garcia

Theses and Dissertations

This research focuses on developing polymer-derived ceramic fibers. The spun micro/nanofibers were sintered into silicon carbide/silicon nitride and tungsten carbide respectively. The relationship between processing, fiber microstructure, morphology, and purity is investigated by scanning electron microscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and thermogravimetric analysis. Dynamic Mechanical Analysis was used to test the reinforcement capabilities of tungsten carbide fibers. EDS identified a near-perfect 1:1 Si-C ratio in silicon carbide fibers sintered between 1200 °C -1400 °C, Silicon carbide was confirmed by FTIR between 1000 °C – 1400 °C. Silicon Nitride peaks were noted in FTIR between 1200 °C – …

Residual Service Life Prognostic Models For Tapered Roller Bearings, Jennifer Danni Lima

Theses and Dissertations

There are a few different bearing health monitoring technologies currently used in the railroad industry, both reactive and preventative detection systems. Reactive models have proven to be ineffective in monitoring bearing health, which has resulted in either unnecessary train stoppages and delays or in-service failures and bearing burn-off leading to catastrophic train derailments. Wayside preventative detection systems, while more effective than reactive technologies, are scarce and neglect railcars’ that do not travel over a specific route. This knowledge prompted the University Transportation Center for Railway Safety at UTRGV to develop an onboard bearing health monitoring system that can accurately assess …