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Masters Theses

2013

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Articles 1 - 23 of 23

Full-Text Articles in Mechanical Engineering

Numerical Modeling Of Infrared Thermography Techniques Via Ansys, Hayder Abdulnabi Thajeel Dec 2013

Numerical Modeling Of Infrared Thermography Techniques Via Ansys, Hayder Abdulnabi Thajeel

Masters Theses

"Several inspection techniques have been developed over years. Recently, infrared thermography (IRT) technology has become a widely accepted as a nondestructive inspection (NDI) technique for different fields and various applications as well. Infrared thermography stands as one of the most an attractive and a successful NDI technique that has ability to detect the object's surface/subsurface defects remotely based on observing and measuring the surface's emitted infrared heat radiation by using an infrared camera. The finite element modeling FEM ANSYS was successfully used for the modelling of several IRT techniques; such as Pulsed Thermography (PT) and Lock-in Thermography ...


Investigation Of The One-Probe And Two-Probe Calibration Integral Equation Methods Using Experimental Data, Abhay Sanjeev Pande Dec 2013

Investigation Of The One-Probe And Two-Probe Calibration Integral Equation Methods Using Experimental Data, Abhay Sanjeev Pande

Masters Theses

This work aims to expand the applicability of the recently devised physics-based Calibration Integral Equation Method (CIEM) at the University of Tennessee Knoxville, for solving the Inverse Heat Conduction Problem (IHCP) as applied to a one-dimensional domain. Contrary to conventional schemes of solving the IHCP, the CIEM does not require the knowledge of the thermo-physical properties of the domain, sensor characterization and sensor probe locations. The pertinent information is implicitly accounted for via an experimental run. The experimental run ‘calibrates’ the physics of the domain and is called the ‘calibration run’. The net surface heat flux during a real ‘unknown ...


A Novel Approach To Multiphysics Modeling Of Heat And Mass Transfer In Porous Media, Seth Allen Pemberton Dec 2013

A Novel Approach To Multiphysics Modeling Of Heat And Mass Transfer In Porous Media, Seth Allen Pemberton

Masters Theses

This thesis aims to investigate conjugate heat and mass transfer in porous media with an emphasis on textiles. Both hygroscopic materials, those that absorb water vapor, and non-hygroscopic materials are examined. A model was developed that utilizes COMSOL’s equation-based partial differential equation (PDE) interface which allows the user to input any equation(s) to be solved. By the use of experimental and numerical data each part of the model, i.e. flow field, gas diffusion, convection and vapor absorption, is verified. The accuracy of the equation-based unsteady flow field is verified by modeling the flow over a circular cylinder ...


Modeling And Validation Of Heat Transfer Present In A Solar Thermal Collector, Eric Ezekiel Stannard Dec 2013

Modeling And Validation Of Heat Transfer Present In A Solar Thermal Collector, Eric Ezekiel Stannard

Masters Theses

A solar absorber panel for a solar water heating system located at the College of Architecture’s New Norris House in Norris, TN was modeled and validated against field data in this work. The purpose of this modeling was to create the foundations of a tool that can be used in collector design and building energy simulations. This tool would take into account the radiometric properties of the collector materials, which are essential for an accurate model. Solar water heaters convert the shortwave energy of the Sun into usable heat for residential and industrial applications and have the potential to ...


Characterization Of Heat Transfer Coefficient Uncertainty In Support Of High Temperature Probe Measurement Technology, Marcus S. Conner Dec 2013

Characterization Of Heat Transfer Coefficient Uncertainty In Support Of High Temperature Probe Measurement Technology, Marcus S. Conner

Masters Theses

The development of new materials and processes have enabled defense, industrial, and research devices that operate in high temperature environments. Measurement technology must keep up with the demand of these environments.

The objective of this work is to provide a correlation between the heat transfer coefficient (and Nusselt Number) and the flow Reynolds number (and Prandtl number) for a truncated cylindrical probe. The correlation provides reduced uncertainty for materials whose heat transfer coefficient is not well defined. The configuration for the experiment uses the University of Tennessee Space Institute’s (UTSI) blow down air supply system discharging into a duct ...


Two-Dimensional Formulation And Quasi-One-Dimensional Approximation To Inverse Heat Conduction By The Calibration Integral Equation Method (Ciem), Hongchu Chen Aug 2013

Two-Dimensional Formulation And Quasi-One-Dimensional Approximation To Inverse Heat Conduction By The Calibration Integral Equation Method (Ciem), Hongchu Chen

Masters Theses

The recently devised calibration integral equation method developed at the University of Tennessee for resolving transient inverse heat conduction in one-dimensional applications is extended and studied in the context of two-dimensional linear inverse heat conduction. This study investigates a simplified plate geometry possessing three known boundary conditions and one unknown boundary condition. This plate contains a series of temperature sensors located on a fixed plane below the surface of interest. To begin the investigation, a quasi-one-dimensional formulation is proposed for predicting the surface heat flux (W/m2) based on a zonal formulation where each zone contains a single thermocouple ...


Water Transport In Polymer Electrolyte Fuel Cells: An Exploration Of Net Water Drag In Real Time, Susan Katherine Reid May 2013

Water Transport In Polymer Electrolyte Fuel Cells: An Exploration Of Net Water Drag In Real Time, Susan Katherine Reid

Masters Theses

Polymer electrolyte fuel cells (PEFCs) are a promising alternative energy source. One challenge preventing widespread use of this technology is water management. A balance must be reached between providing sufficient water for membrane ionic conductivity while maintaining low enough water content to mitigate the reduction of available reaction sites in the cathode catalyst layer due to liquid water build up. Much exploration of this area of fuel cell research has been conducted, but the details of water transport in an operating fuel cell are not yet fully understood. The motivation of this work was to elucidate mass transport phenomena occurring ...


A Decision Support Methodology For Improving Equipment Reliability, Caiqiao Xu May 2013

A Decision Support Methodology For Improving Equipment Reliability, Caiqiao Xu

Masters Theses

Purpose - Aggressive Maintenance Strategy can improve the overall operation and reliability through redesigning or modifying equipment. A decision support tool is proposed that could aid in discovering the many options and in selecting the best approach for redesigning or for modifying the equipment. The new tool has three sections that correspond to the equipment life cycle:

1. Keeping the equipment in perfect running condition.
2. Identifying defects as soon as the equipment starts to degrade.
3. Minimizing losses after the equipment has ceased functioning.

Design/Methodology – The first section seeks to keep the equipment running in perfect condition. There are ...


Neutron Imaging Of Lithium Inside A High-Temperature Heat Pipe, Eric Henry Kirchoff May 2013

Neutron Imaging Of Lithium Inside A High-Temperature Heat Pipe, Eric Henry Kirchoff

Masters Theses

Neutron imaging of a high-temperature Mo-Li [molybdenum-lithium] heat pipe has been performed to assess Li flow visualization. The high neutron attenuation cross section of Li allows for imaging inside the heat pipe shell structure, which has a lower value of neutron attenuation, making neutron radiography an ideal choice for characterizing Li movement.

The gravity assisted, cylindrical heat pipe was heated to 903oC [degree] using a wire resistance Mo heater operating under vacuum. This Mo-Li heat pipe is 35 cm long with a square internal geometry 2.2 cm per side, utilizing small corner radii as the wicking structure ...


Direct Measurement Of Through-Plane Thermal Conductivity Of Partially Saturated Fuel Cell Diffusion Media, Guoqing Xu May 2013

Direct Measurement Of Through-Plane Thermal Conductivity Of Partially Saturated Fuel Cell Diffusion Media, Guoqing Xu

Masters Theses

Polymer electrolyte fuel cells (PEFCs) are predicted by many as the most feasible alternative to heat engines and for battery replacement in automotive, portable, and stationary power applications. Fuel cell performance and durability are inseparably related to the presence of liquid water throughout the fuel cell system. To better understand the mechanical and thermal characterization of diffusion media (DM) is essential to PEFC DM design, optimization and production to improve water and thermal managements. Diffusion media are one of the important components in PEFCs in terms of the reactant permeability, the product permeability, the electronic conductivity, the heat conductivity, and ...


Manufacturing And Characterization Of Polyurethane Based Sandwich Composites, Stephen Robert Hawkins Jan 2013

Manufacturing And Characterization Of Polyurethane Based Sandwich Composites, Stephen Robert Hawkins

Masters Theses

"Composite sandwich structures have been extensively employed in aerospace structures, ship building, infrastructure, etc. due to their light weight and high strength to weight ratio. The understanding of their behavior under impact and environmental conditions is extremely important for the design and manufacturing of these engineering structures since these problems are directly related to structural integrity and safety requirements. Vacuum assisted resin transfer molding (VARTM) is one of the commonly used low cost composite manufacturing processes. Polyurethane (PU) resin system has been observed to have better mechanical properties and higher impact strength when compared to conventional resin systems such as ...


Development Of A Methodology For Pseudo-Rigid-Body Models Of Compliant Segments With Inserts, And Experimental Validation, Raghvendra Sharadchandra Kuber Jan 2013

Development Of A Methodology For Pseudo-Rigid-Body Models Of Compliant Segments With Inserts, And Experimental Validation, Raghvendra Sharadchandra Kuber

Masters Theses

"Compliant mechanisms have shown a great deal of potential in the last few decades in providing better solutions to design problems with numerous benefits; however, their use has been limited due to current challenges in the material selection. With ever increasing focus on the applications of compliant mechanisms, it is necessary to find alternatives to the existing materials and methods of prototyping. The purpose of this work is to develop a methodology for pseudo-rigid-body models of compliant segments with compliant inserts, comprised of a resilient material placed between the layers of a softer material, to alleviate any creep and strength ...


A New Method For Failure Modes And Effects Analysis And Its Application In A Hydrokinetic Turbine System, Liang Xie Jan 2013

A New Method For Failure Modes And Effects Analysis And Its Application In A Hydrokinetic Turbine System, Liang Xie

Masters Theses

"The traditional failure modes and effects analysis (FMEA) is a conceptual design methodology for dealing with potential failures. FMEA uses the risk priority number (RPN), which is the product of three ranked factors to prioritize risks of different failure modes. The three factors are occurrence, severity, and detection. However, the RPN may not be able to provide consistent evaluation of risks for the following reasons: the RPN has a high degree of subjectivity, it is difficult to compare different RPNs, and possible failures may be overlooked in the traditional FMEA method. The objective of this research is to develop a ...


Dynamic Contact Analysis Of A Piezoelectrically Driven Ultrasonic Crawler-Actuator, Dwight Santiago Maness Jan 2013

Dynamic Contact Analysis Of A Piezoelectrically Driven Ultrasonic Crawler-Actuator, Dwight Santiago Maness

Masters Theses

"A standing wave ultrasonic motor (SWUM) is presented in this thesis. The actuator is piezoelectrically powered and operates in the first and second bending modes to move forwards and backwards, respectively. The kinematic stability of the crawler, backed by experimental results is shown in the first paper presented in this thesis. This study demonstrates that in the absence of a preload or kinematic constraints, the crawler shows vertical stability. A full transient analysis using the finite element method is performed characterizing the speed and contact variables is conducted in the second paper. The results show that given enough time the ...


Processing Of Continuous Fiber Reinforced Ceramic Composites For Ultra High Temperature Applications Using Organosilicon Polymer Precursors, James Robert Nicholas Jan 2013

Processing Of Continuous Fiber Reinforced Ceramic Composites For Ultra High Temperature Applications Using Organosilicon Polymer Precursors, James Robert Nicholas

Masters Theses

"The current work is on the development of continuous fiber reinforced ceramic materials (CFCCs) for use in ultra high temperature applications. These applications subject materials to extremely high temperatures (> 2000⁰C). Monolithic ceramics are currently being used for these applications, but the tendency to fail catastrophically has driven the need for the next generation of material. Reinforcing with continuous fibers significantly improves the toughness of the monolithic materials; however, this is a manufacturing challenge. The development of commercial, low-viscosity preceramic polymers provides new opportunities to fabricate CFCCs. Preceramic polymers behave as polymers at low temperatures and are transformed into ceramics upon ...


Paste Development And Co-Sintering Test Of Zirconium Carbide And Tungsten In Freeze-Form Extrusion Fabrication, Ang Li Jan 2013

Paste Development And Co-Sintering Test Of Zirconium Carbide And Tungsten In Freeze-Form Extrusion Fabrication, Ang Li

Masters Theses

"Ultra-high temperature ceramics are being investigated for future use in aerospace applications due to their superior thermo-mechanical properties, as well as oxidation resistance, at temperatures above 2000°C. However, their brittle properties make them susceptible to thermal shock failure. Components fabricated as functionally graded materials (FGMs) can combine the superior properties of ceramics with the toughness of an underlying refractory metal by fabricating graded composites. This paper discusses the grading of two materials through the use of a Freeze-form Extrusion Fabrication (FEF) system to build FGMs parts consisting of zirconium carbide (ZrC) and tungsten (W). Aqueous-based colloidal suspensions of ZrC ...


Parameter Optimization For Controlling Aluminum Loss When Laser Depositing Ti-6al-4v, Richard Charles Barclay Jan 2013

Parameter Optimization For Controlling Aluminum Loss When Laser Depositing Ti-6al-4v, Richard Charles Barclay

Masters Theses

"The ability to predict the mechanical properties of engineering materials is crucial to the manufacturing of advanced products. In the aerospace industry, Ti-6Al-4V is commonly used to build structures. Any deviation from the alloy's standard properties can prove detrimental. Thus, the compositional integrity of the material must be controlled. The ability to directly build and repair large, complicated structures directly from CAD files is highly sought after. Laser Metal Deposition (LMD) technology has the potential to deliver that ability. Before this process can gain widespread acceptance, however, a set of process parameters must be established that yield finished parts ...


Transmission Shaft Design For Hydrokinetic Turbine With Reliability Consideration, Goutham Pusapati Jan 2013

Transmission Shaft Design For Hydrokinetic Turbine With Reliability Consideration, Goutham Pusapati

Masters Theses

"Hydrokinetic energy, a relatively new kind of renewable energy, can be generated from flowing water in rivers or oceans. Hydrokinetic turbines (HKTs) are a major system for hydrokinetic energy, and the reliability of the HKTs is critical for both their lifecycle cost and safety. The objective of this work is to apply advanced methodologies of reliability analysis and reliability-based design to the transmission shaft design for a horizontal-axis, non-submerged HKT. The deterministic shaft design is performed first by considering failure modes of strength and deflection using distortion energy, maximum shear and deflection theories. Then the reliability analysis of the shaft ...


A Generalized Approach For Compliant Mechanism Design Using The Synthesis With Compliance Method, With Experimental Validation, Ashish B. Koli Jan 2013

A Generalized Approach For Compliant Mechanism Design Using The Synthesis With Compliance Method, With Experimental Validation, Ashish B. Koli

Masters Theses

"Compliant mechanisms offer numerous advantages over their rigid-body counterparts. The synthesis with compliance technique synthesizes compliant mechanisms for conventional rigid-body synthesis tasks with energy/torque specifications at precision positions. In spite of its usefulness, the method suffers from some limitations/problems. The purpose of this work is to investigate these sensitivities with the synthesis with compliance technique and improve upon existing method. A new, simple but efficient, method for synthesis with compliance using an optimization approach is proposed, and its usefulness and simplicity demonstrated over the existing method. The strongly and weakly coupled system of kinematic and energy/torque equations ...


Development Of A Postprocessor For A Multi-Axis Cnc Milling Center, Mihir Satish Adivarekar Jan 2013

Development Of A Postprocessor For A Multi-Axis Cnc Milling Center, Mihir Satish Adivarekar

Masters Theses

"Most of the current college design and manufacturing curricula are primarily focused on computer aided design (CAD), while less emphasis is given to computer aided manufacturing (CAM). A great opportunity has been missed as the benefits of CAD/CAM cannot then be fully learned. Postprocessor plays a vital role in integration of CAD//CAM with computer numerically controlled (CNC) machines. Hence, postprocessor must be developed accurately. This thesis is composed of one paper. Paper I proposes a novel methodology to determine compensation vectors for the post processor of multi-axis milling center. The new approach that has been implemented in Paper ...


A Friction Prediction Model For Small Si Engines, Avinash Singh Jan 2013

A Friction Prediction Model For Small Si Engines, Avinash Singh

Masters Theses

"A substantial portion of the input fuel energy in an SI engine is lost towards overcoming the frictional forces from various rubbing parts. These frictional losses are very significant in small engines and these losses can be reduced by incorporating some design changes. A semi-empirical friction prediction model was studied and modified with the help of the experimental results for small SI engines. This model is dependent upon engine geometry and speed. The model divides the frictional work into different sub-assemblies of the engine and these sub-assemblies are in turn divided to determine the friction associated with individual components. A ...


Water Management Capabilities Of Bio-Inspired Flow Field Configurations For Polymer Electrolyte Membrane Fuel Cells, Nicholas Warren Freer Jan 2013

Water Management Capabilities Of Bio-Inspired Flow Field Configurations For Polymer Electrolyte Membrane Fuel Cells, Nicholas Warren Freer

Masters Theses

"Fuel cells have received an increasing amount of attention over the past decade for their power production capabilities. Polymer electrolyte membrane (PEM) fuel cells in particular are researched because of their high power density, large range of operating conditions, green products, and ease of scalability. PEM fuel cells do have a number of issues that reduce their overall performance. These issues include variations in reactant distribution, materials issues for the bipolar plate, and flooding caused by poor water management. Variations in the reactant distribution causes lower overall power output due to regions of low reactant density. This means that optimizing ...


Part Height Control Of Laser Metal Additive Manufacturing Process, Yu-Herng Pan Jan 2013

Part Height Control Of Laser Metal Additive Manufacturing Process, Yu-Herng Pan

Masters Theses

"Laser Metal Deposition (LMD) has been used to not only make but also repair damaged parts in a layer-by-layer fashion. Parts made in this manner may produce less waste than those made through conventional machining processes. However, a common issue of LMD involves controlling the deposition's layer thickness. Accuracy is important, and as it increases, both the time required to produce the part and the material wasted during the material removal process (e.g., milling, lathe) decrease. The deposition rate is affected by multiple parameters, such as the powder feed rate, laser input power, axis feed rate, material type ...