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Articles 1 - 10 of 10
Full-Text Articles in Mechanical Engineering
Development Of A Low Cost Handheld Microfluidic Phosphate Colorimeter For Water Quality Analysis, Sean C. Kaylor
Development Of A Low Cost Handheld Microfluidic Phosphate Colorimeter For Water Quality Analysis, Sean C. Kaylor
Master's Theses
This thesis describes the design, fabrication, and testing process for a microfluidic phosphate colorimeter utilized for water quality analysis. The device can be powered by, and interfaced for data collection with, a common cell phone or laptop to dramatically reduce costs. Unlike commercially available colorimeters, this device does not require the user to measure or mix sample and reagent. A disposable poly(dimethylsiloxane) (PDMS) microfluid chip, powered by an absorption pumping mechanism, was used to draw water samples, mix the sample at a specific ratio with a molybdovanadate reagent, and load both fluids into an onboard cuvette for colorimetric analysis. A …
Short-Term Failure Analysis Of Aluminum Conducting Composite Core Transmission Lines, Brian Burks
Short-Term Failure Analysis Of Aluminum Conducting Composite Core Transmission Lines, Brian Burks
Electronic Theses and Dissertations
Recently the inefficiency and lack of capabilities of electric energy transmission have been put in the global spotlight; a transmission line design known as the Aluminum Conducting Composite Core Trapezoidal Wire (ACCC/TWTM) attempts to eliminate the deficiencies. The ACCC core is comprised of a new hybrid composite material. The most probable causes of short-term damage to the ACCC core were investigated through a series of finite element models. It was found that excessive bending was the most likely cause of short-term damage to the core. During bending of the ACCC core, stresses are concentrated at the interface in …
Design And Development Of Rapid Battery Exchange Systems For Electric Vehicles To Be Used As Efficient Student Transportation, Jonathan A. Bevier
Design And Development Of Rapid Battery Exchange Systems For Electric Vehicles To Be Used As Efficient Student Transportation, Jonathan A. Bevier
Master's Theses
Rapid battery exchange systems were built for an electric van and pedal assist electric bike as a method of eliminating the need to recharge the vehicles batteries in order to increase the feasibility of using electric propulsion as a method of efficient student transportation. After selecting proper materials it was found that the systems would need a protective coating to ensure consistent operation. 1020 cold rolled steel samples coated with multiple thicknesses of vinyl resin paint, epoxy resin paint, and powder coating were subjected to environmental wear tests in order to determine if the type and thickness of common protective …
Numerical/Experimental Investigation Of Plunge Stage And Effect Of Donor Material In Friction Stir Welding, Saptarshi Mandal
Numerical/Experimental Investigation Of Plunge Stage And Effect Of Donor Material In Friction Stir Welding, Saptarshi Mandal
Mechanical & Aerospace Engineering Theses & Dissertations
Friction Stir Welding (FSW) was developed in 1991 as a robust solid-state joining technique that uses a specially shaped rotating tool to generate heat and plasticize material around the tool. The tool then mixes plasticized material along the joint line to produce the weld. Over the last decade, FSW has become increasingly popular for welding aluminum. The combination of attractive properties of the weld and cost-efficiency has led researchers to investigate the feasibility of using FSW for steel. One of the major impediments for using friction stir welding for harder materials such as steel is tool wear. It is well-documented …
Modulated Nanopores Using Pulse Anodization On Thin Aluminum, Mahesh Babu Gunukula
Modulated Nanopores Using Pulse Anodization On Thin Aluminum, Mahesh Babu Gunukula
UNLV Theses, Dissertations, Professional Papers, and Capstones
Nanoporous anodic aluminum oxide has traditionally been made in one of two ways: "Mild Anodization (MA)" or "Hard Anodization (HA)". The former method produces self-ordered pore structures but it is slow and only works for a narrow range of processing conditions; the latter method, which is widely used in the aluminum industry, is faster but it produces films with disordered pore structures. Here we report a novel approach termed "pulse anodization" that combines the advantages of the MA and HA processes. By designing the pulse sequences it is possible to control both the composition and pore structure of the anodic …
Ceramic Matrix Composite Characterization Under A Combustion And Loading Environment, Andrew R. Nye
Ceramic Matrix Composite Characterization Under A Combustion And Loading Environment, Andrew R. Nye
Theses and Dissertations
Lightweight materials that can withstand high temperatures and corrosive environments are constantly sought after in the aerospace industry, typically for Gas Turbine Engine (GTE) application. These materials need to retain their strength throughout the long service period they would see in the combustor and turbine components of a GTE. One material that is ideal for these types of applications is an oxide/oxide Ceramic Matrix Composite (CMC). The fatigue behavior of the oxide/oxide CMC NextelTM 720/Alumina (N720/A) was investigated in a unique high temperature environment. N720/A consisted of an 8-harness satin weave of NextelTM aluminum oxide/silicon oxide fibers bound …
Impacting Testing Of High Temperature Ceramics Through The Use Of A Vitiated Heater For Hot And Cold Fire Collisions, Adrian Trejo
Impacting Testing Of High Temperature Ceramics Through The Use Of A Vitiated Heater For Hot And Cold Fire Collisions, Adrian Trejo
Open Access Theses & Dissertations
Material testing is a crucial step during the design process as particular materials serve as safety and life saving conditions. In this study, a MoSi2 is chosen as the target specimen to undergo impact under high temperatures. An impact apparatus is designed and constructed for the purpose of propelling alumina particles at high velocities. A nozzle using compressed nitrogen gas is used to fire the particle at the desired velocities. Due to the possibility of thermal shock occurring at higher temperatures, a separate nozzle utilizing vitiation heating is designed to fire the particle at equally higher temperatures to prove the …
Oxidation Modeling By Means Of Molecular Dynamics, Chaiyod Soontrapa
Oxidation Modeling By Means Of Molecular Dynamics, Chaiyod Soontrapa
UNLV Theses, Dissertations, Professional Papers, and Capstones
Oxidation modeling is normally engineered to study systems at macroscopic scales, mostly in analytical forms based on diffusion theories. The associated time scale is usually in months, days, or minutes, and the length scale is in the order of microns. In this dissertation, oxidation modeling is performed at atomistic scale with the time and length scales in picoseconds and angstroms, respectively, using molecular dynamics. Molecular dynamics simulations generate trajectories of each atom or particle in a system according to the laws of physics. Studying oxidations under the atomistic point of view can offer new insights on atomic behaviors and influencing …
Fracture Toughness, Crack-Growth-Rate And Creep Studies Of Alloy 276, Joydepp Pal
Fracture Toughness, Crack-Growth-Rate And Creep Studies Of Alloy 276, Joydepp Pal
UNLV Theses, Dissertations, Professional Papers, and Capstones
Austenitic nickel-base Alloy 276 had been proposed to be a candidate structural material within the purview of the nuclear hydrogen initiative program. A mechanistic understanding of high temperature tensile deformation of this alloy has already been presented in an earlier investigation. The current investigation has been focused on the evaluation of crack-growth behavior, fracture toughness, stress-corrosion-cracking and creep deformation of this alloy as functions of different metallurgical and mechanical variables. The results of crack-growth study under cyclic loading indicate that this alloy exhibited greater cracking tendency with increasing temperature at a constant load ratio (R). However, the effect of temperature …
Effects Of Mechanical And Metallurgical Variables On Creep, Fracture Toughness And Crack Growth Behavior Of Alloy 617, Muhammad Hasibul Hasan
Effects Of Mechanical And Metallurgical Variables On Creep, Fracture Toughness And Crack Growth Behavior Of Alloy 617, Muhammad Hasibul Hasan
UNLV Theses, Dissertations, Professional Papers, and Capstones
Nickel base Alloy 617 has been identified to be a suitable structural material for heat exchanger applications in both hydrogen and electricity generation using nuclear heat. A maximum operating temperature of 950°C has been specified by department of energy (DOE) for both applications to achieve a maximum possible efficiency. Therefore, an extensive investigation has been pursued to evaluate time-dependent-deformation (Creep) of this alloy as functions of temperature and applied load. The results indicate that this alloy exhibited severe creep deformation, characterized by development of an instantaneous tertiary creep region at 850 and 950°C under applied stresses corresponding to its 35% …