Engineering Commons^™

Selective Laser Sintering Of 13-93 Bioactive Glass, Krishna C. R. Kolan

Masters Theses

"Bioactive glasses are promising materials for bone scaffolds due to their ability to assist in tissue regeneration. When implanted in vivo, bioactive glasses can convert to hydroxyapatite, the main mineral constituent of human bone and form a strong bond with the surrounding tissues, thus providing an advantage over polymer scaffold materials. Bone scaffold fabrication using additive manufacturing techniques like selective laser sintering (SLS) provide control over pore interconnectivity during the fabrication of scaffold, which helps in mimicking human trabecular bone. 13-93 glass, a third-generation bioactive material designed to accelerate the body's natural ability to heal itself, was used in …

Development Of A Graphical User Interface For The Study Of Parallel-Connected Solar Arrays, Nisha Nagarajan

Masters Theses

"For any solar array it is necessary to be able to harness the maximum possible power from it. A new technology is proposed to improve the efficiency of solar arrays and harness maximum potential power as well by connecting the solar panels in parallel. This thesis describes the development of a graphical user interface for the evaluation of this parallel-connected solar array technology and to compare different scenarios for solar arrays to predict the potential power output to decide the best configuration for an application. This is done via several computations and analysis of field data. The first paper describes …

Economic Evaluation Of Sustainable Strategies For The Transportation Sector, Yaqin Lin

Masters Theses

"Sustainable strategies are drawing growing attention as global environmental challenges increase concerns over energy consumption. As one of the most intensive consumers of energy, the transportation sector has a particular need to go green. Implementing alternative energy sources and applying advanced energy efficient technologies are two major approaches to achieve sustainability. Much work thus far used cost-effectiveness as an important criterion for assessing the practicability of sustainable strategies. However, few studies have evaluated such strategies systematically. This thesis has developed a framework of cost-effectiveness analysis to assess sustainability strategies. The framework summarizes the various effects of five representative alternative energy …

Experimental Investigation Of Cutting Forces, Temperature And Surface Roughness In End-Milling Of Hastelloy C-2000, Ryan Matthews

Masters Theses

"This thesis presents the results of experimental investigation of the effects of cutting parameters (spindle speed, feed per tooth, axial depth of cut and radial depth of cut) on the three components of cutting forces (F_x, F_y, F_z), workpiece temperature and surface roughness in end-milling of Hastelloy C-2000 alloy using design of experiments (DOE) and response surface methodology (RSM). End-milling experiments were conducted using 0.5 inch diameter end-mill on Cincinnati Milacron Sabre 750 vertical machining center using water based flood coolant. An inscribed central composite design of experiment was used to study the four …

Fabrication Of Sers Active Nanostructures By Femtosecond Laser Micromachining, Matthew Aaron Olson

Masters Theses

"This work investigated the surface-enhanced Raman scattering (SERS) enhancement of gold nanoparticles on femtosecond laser created nanostructures on a silicon wafer. The goal was to use the nanostructures to assemble the nanoparticles into three-dimensional aggregates and compare these enhancements to those of two dimensional aggregates. The SERS enhancement generated by the three-dimensional structures was on average 5 x 10⁴ with a high enhancement of 1.2 x 10⁵. The magnitude of this enhancement was on par with previous experiments that tested SERS enhancements on gold nanoparticles, but it did not show any significant enhancement caused by the three-dimensional nature of the …

Electrodeposition Of Metallic Gas Diffusion Layers For Use In Pem Fuel Cells, Gargi Tandra

Masters Theses

"This work developed a novel method of using Electrodeposition techniques to fabricate metallic gas diffusion layers (GDLs) for application in proton exchange membrane fuel cells. These GDLs improve the electrical and thermal conductivity of the fuel cells, and their straight, noncircular pores remove water efficiently. The Electrodeposition technique used here relies on a sacrificial copper anode and an aluminum sheet 50 µm thick acts as a cathode. Unlike the other laboratory based methods available for the fabrication of metallic GDLs, this method is simple and cost effective. With controlled deposition parameters and a chemical lift-off process that corrodes the aluminum …

Development Of Virtual Engineering Simulation For Lean Education, Akalpit Kiran Gadre

Masters Theses

"Global competition and customer demands are pressing modern industry operations to become leaner. The race among the global corporations to "go lean" demands engineers with an in-depth understanding of lean philosophies. An overview of current methods for teaching lean shows that they include small scale hands-on projects, presentations, and guest lectures. There is a need to incorporate a more immersive virtual simulation to further inspire students. Many lean simulation games are available in the market; however, they lack simplicity, ability to store the results, and modeling power.

The goal of this research is to develop a virtual simulation platform, enabling …

Memristor Based Lookup Table - Novel Testing And Reconfiguration Techniques, Veeresh Anilkumar Hongal

Masters Theses

"Nanotechnology is soon predicted to replace the CMOS technology, as current CMOS lithographic techniques will become void for complex IC designs with smaller feature size, and are hence incapable of keeping up with Moore's law. The devices in nanotechnology are fabricated using bottom up self-assembly. Memristor is one promising nanotech device which can replace the transistor used as a switch or memory device as it is just half the size and uses only fraction of the energy. This work considers Memristor Look Up Table (MLUT) design, which is a building block for asynchronous FPGAs built with memristors. In spite of …

Risk Assessment For Conceptual Design Of Hydrokinetic Turbines, Praveen Kailkere Srinivas

Masters Theses

"Hydrokinetic energy is a relatively new concept in the field of renewable energy. The rotor of the turbine, immersed in water, uses the velocity from the flowing water to generate power. Thus the hydrokinetic turbines are also known as zero head turbines. These turbines can be installed in rivers, oceans and sea beds. The design of these systems depends on the site conditions, installation and maintenance costs. Since this technology has not been assessed for its potential power producing capabilities, not much research has been done in order to harness this form of renewable energy and to study the impact …

Optimized Testing And Logic Mapping Methodology For Caen-Based Nano-Circuits, Sambhav Kundaikar

Masters Theses

"Nanotechnology has been shown to have the potential to replace the existing CMOS technology in the race to maintain the Moore's Law increases in IC complexity. This work considers the Chemically Assembled Electronic Nanotechnology (CAEN), which fabricates nanofabric using a low cost self-assembly and self-alignment chemical process and provides very high density. However, the main disadvantage of this technology is the inherently high defect rate that hinders the efforts to commercialize such systems. Existing testing and design techniques, for example for FPGAs, are ill suited since they typically assume vary low defect rates.

This thesis is comprised of two papers. …

Mesh Optimization Of Finite Element Models Of Wellbore Stress Analysis, Ming-Yen Lee

Masters Theses

"Numerical modeling methods such as the widely used finite element method provide an excellent opportunity to analyze the wellbore state of stress for a variety of applications such as wellbore integrity, wellbore design or hydraulic fracturing. However, numerical modeling methods introduce errors by nature and may not precisely match the analytical solution if the meshing of the numerical model is not carefully taken care of. This study presents a parametric study of the meshing parameters mesh density, element type, and model size for 2-dimensional and 3-dimensional vertical wellbore models under three different types of boundary conditions, and a guideline for …

Development Of Virtual Cnc Machine Tools And Web-Based Machining Process Simulation: Mechanistic Cutting Force Models And Determination Of Specific Force Coefficients In Helical End Milling, Vinay Rao Talekar

Masters Theses

"This thesis presents the results of the investigations of mechanistic modeling and simulation of cutting forces in high speed end milling of titanium alloy, Ti-6Al-4V, and the determination of specific cutting and edge force coefficients for carbide bull-nose helical end-mill. A generalized mathematical model representing the outer geometry of an end-mill and the cutter edge geometry is presented. Mechanistic cutting force models have been developed for a general helical end-mill and modeled specifically for a bullnose helical end-mill. A MATLAB code for the mechanistic cutting force models have been developed for the simulation of cutting force components in end milling …

A Comparison Of Bootstrap, Binomial Inference, And Monte Carlo Methods For Demand Distribution Modeling, Swithin Samuel Razu

Masters Theses

"Analysis of customer preferences is one of the most important tasks in new product development. How customers come to appreciate and decide to purchase a new product impacts market share and, therefore, the success of the new product. Unfortunately, when designers select a product concept early in the product development process, the "true" customer preferences and therefore, market share of the new product is unknown. Conjoint analysis is a statistical methodology that has been used to forecast the market share of a product concept from customer preference survey data. Although conjoint analysis has been increasingly incorporated in design research as …

Electron Transport Through Two Irreducibly-Coupled Aharonov-Bohm Rings With Applications To Nanostructure Quantum Computing Circuits, Casey Andrew Cain

Masters Theses

"A thorough investigation was conducted into the six fundamental classes of two coupled Aharonov-Bohm rings that share a finite center common path, when the phase of the electron wave function was modulated by two distinct magnetic fluxes. The coupling is similar to two coupled atoms. The behavior of charge accumulation along the center common path or equivalently the bonding and anti-bonding of the two rings can be achieved as the two applied fluxes are varied. Thus when three external terminals are connected to such coupled rings, the behavior of the electron transport is divided into several classes depending on the …

Crack Formation In Investment Casting Ceramic Shells, W. A. Everhart

Masters Theses

"This thesis is a collection of papers that discuss shell cracking in investment casting during pattern removal. The application of rigid polymeric foam for large investment casting patterns with complex geometries can improve the dimensional tolerances and the surface quality of the casting. However, these pattern materials have a tendency to promote crack formation in investment casting shells during pattern removal by firing.

The first two papers discuss the factors affecting shell cracking and methods to prevent it. Experimental methods were combined with finite element modeling to predict stress in the shell. A 3D nonlinear finite element model was developed …

Evaluation Of Skin-Core Adhesion Bond And Low-Velocity Impact Behavior Of Honeycomb Sandwich Structures, Ramanjaneya R. Butukuri

Masters Theses

"Composite sandwich structures offer several advantages over conventional structural materials such as lightweight, high bending and torsional stiffness, superior thermal insulation and excellent acoustic damping. Some of the failure mechanisms in a composite sandwich structure are de-bonding of the composite facesheets from the core structure and damage due to low-velocity impact. In the first part of this work, adhesive fillet formation and adhesive mechanical strength are evaluated as a function of several different sandwich construction design variables. The effect of film adhesive thickness is studied. A process for reticulation of the adhesive is applied and studied. Optimized combinations of core …

Development Of Lower Cost Imaging Systems For Laser Metal Deposition Process, Shyam Barua

Masters Theses

"Laser Metal Deposition (LMD) has been used as an additive manufacturing process in industries such as aerospace and die castings. LMD is especially useful in repair applications involving die repair. However, it is still not used widely in industry due to variations in the quality of parts. There are multiple interactions between various factors which influence the quality of deposit.

There exists a need for defect detection systems to detect any changes in the deposition quality during deposition. On demand detection enables adjustment in process parameters and minimization of rework cost.

Vision systems have been used extensively in the industry …

A Neural Network Based Approach For Path Planning On Costmap, Songjie Chen

Masters Theses

"In this thesis, a path planning method using a three-level hierarchical system model is proposed. In the top level of the hierarchy, the given location points to visit are taken as waypoints. The waypoint navigation process is formulated as a traveling salesman problem (TSP). The Lin-Kernighan algorithm is used to solve the TSP and transfer the solution to the lower level of the hierarchy. In the middle level, the path is represented by a grid-based costmap. A novel modified Grossberg neural network is designed to solve the point-to-point path planning. The bottom level of the hierarchy smoothens the path with …

"Long" Carbon Fiber Reinforced Concrete For Impact And Blast Resistance, Benjamin Paul Gliha

Masters Theses

"One of the most commonly used materials for protective structures and construction is traditional reinforced concrete. However, in a blast, conventional reinforced concrete (RC) is susceptible to significant spalling (small to medium size chunks of concrete detaching from the original member). The force of the blast turns spalled concrete into projectiles, resulting in secondary fragmentation and the majority of loss of life. Furthermore, the concrete debris makes for difficult and uncertain footing. Both phenomena endanger personnel and complicate post-blast recovery efforts. A very promising but barely explored change to conventional RC construction is the addition of "long" carbon fibers (fibers …

Intelligent Control Of Smartparks And Wind Farms In Smart Grids, Priyam Chakravarty

Masters Theses

"With development in wind turbine technology, wind energy has become an important contestant in the utility market. However, wind energy has the intrinsic property of variations which causes fluctuations in the power grid.

Plug-in electric vehicles are drawing the attention of researchers and the electric power industry because of its need for charging from the grid and its ability to store energy. With increase in the numbers of plug-in electric vehicles, there will be significant penetration of distributed energy resources and hence plug-in electric vehicles connected to the grid in parking lots (SmartParks) can be used as energy storage sink …

Life Expectancy Evaluation And Replacement Schedule Development For Led Traffic Indicators, Casey Robert Noll

Masters Theses

"LED (light-emitting diode) technology is being widely adopted for use in sustainable traffic signal management. However, the useful life and luminosity characteristics have not been sufficiently studied in the field to provide departments of transportation with cost-effective replacement strategies based on the realities for LED indicators. LED indicators fail when their luminous intensity (LI) falls below a pre-specified threshold, posing a danger to traffic. This research details a field study of LED indicators in Missouri and develops a replacement schedule based on key findings. Rates of degradation and subsequently the useful life of each type of LED indicator were calculated …

Pressed Powdered Titanium And Aluminum Conical Shaped Charge Penetration Of Geological Targets, Dominique John Nolan

Masters Theses

"Conical Shaped Charge penetration into rock is dependent on the physical characteristics of the rock itself and the design and composition of the shaped charge conducting the work. This study looks at the effects of a non-typical conical shaped charge and its penetration into four different rock targets. The shaped charge is made of a liner, which is not a typical solid but instead is a pressed powdered metallic compound of Titanium (Ti) and Aluminum (AI).

The study presents the raw data from testing against rock targets that range in density, uniaxial compressive strength (UCS), tensile strength, hardness scales, and …

Quantitative Oxygen Imaging With A Display Screen And A Color Camera, Sanghan Park

Masters Theses

"Optical oxygen sensing uses luminophores such as metal complex dyes that respond to oxygen when illuminated by their specific excitation wavelengths. Traditional optical instruments are mostly spectrometric instruments based on the measurements of emission, absorption or reflection. There is, however, a great need to develop simple, economical, photometric detection components toward quantitative and two-dimensional imaging instruments.

In this work, familiar optoelectronic devices were utilized to demonstrate a simple determination method of gaseous oxygen both quantitatively and qualitatively. A liquid crystal display (LCD) screen and a color charge-coupled device (CCD) camera were employed as a light source for fluorescence excitation and …

Design, Analysis, And Optimization Of Composite Structures For Aerospace Applications, Tyler Jason Keil

Masters Theses

"This thesis contains three papers that focus on composites that pertain to a variety of structures commonly found in the aerospace industry. The first paper presents an investigation of the stowage and deployment strength of a thin carbon fiber-reinforced polymer shell capable of being rolled and stowed in a tight rolled configuration. The intent of this structure is for use as a segment of a larger deployable reflective aperture. This study involved finite element analysis of several laminates, coupon-level and full-scale prototype testing, which provided a much needed insight and benchmark of composite shells used in this manner.

The second …

Innovative Air Breathing Design And Output Control For Portable Proton Exchange Membrane Fuel Cell, Amar Bala Sridhar

Masters Theses

"Proton Exchange Membrane (PEM) Fuel Cell Technology is an energy source that can provide several times more energy per unit volume than current lithium ion batteries that are available in the market today. The barriers that exist that prevent the fuel cell from entering the world of portable applications are mainly system architecture integration. The idea is to have a fully functioning fuel cell with optimum power output using an innovative chimney design. Tests were conducted to quantify the advantage of using a chimney with the fuel cell. Further research was done to shed light on how different chimney designs …

A Statewide Analysis Of Highway Safety In Arkansas, Uday R. R. Manepalli

Masters Theses

"This research concentrated on two major aspects of highway safety analysis, hotspot identification and identification of crash contributing factors on highways. The objective of the first part of this thesis is to evaluate two crash frequency, three crash severity and two composite hotspot ranking methods. Based on the limitations of the existing hotspot identification methods (HSID), crash factor method (CFM), a crash severity based HSID method is proposed. A composite rank method (F 1) based on principal component analysis is also proposed. These methods are evaluated using three tests, the site consistency test, the method consistency test, and the total …

Arteriogenesis And Ischemia Impair Functional Vasodilation In Resistance Arteries, Trevor Cardinal, Joseph S. Zhu, Kyle R. Struthers, Thomas J. Kesler, Matthew D. Yocum

Biomedical Engineering

No abstract provided.

Accessible Rich Internet Applications: The Search Engine Challenge, Angela Kielthy

Conference papers

The perception that Rich Internet Applications (RIAs) and Accessible Rich Internet Applications (ARIAs) are inaccessible to search engines is perhaps one of the main factors that hinder their wider adoption by the web development community. Recent announcements that RIAs and ARIAs are becoming more search engine friendly is provoking web developers to look for further information and evidence that will support or refute these announcements.

This paper outlines research undertaken and tests performed to establish if RIAs and ARIAs developed using Adobe Flex are crawlable and indexable by the Google search engine by default.

The conclusion drawn from testing is …

Arterial Tissue Perforation Using Ultrasonically Vibrating Wire Waveguides, Mark Wylie

Doctoral

Chronic Total Occlusions (CTOs) are fibrous and calcified atherosclerotic lesions which completely occlude the artery. They are difficult to treat with standard dilation procedures as they cannot be traversed easily. Their treatment is also associated with a high risk of arterial perforation. Low frequency ultrasonic vibrations delivered via wire waveguides represent a minimally invasive treatment for CTOs and other tissue ablation applications. These devices typically operate at 20–50 kHz delivering wire waveguide distal tip amplitudes of vibration of 0-60 μm. The diseased tissue is ablated or disrupted by repetitive direct mechanical contact and cavitation. This research assesses the susceptibility of …

X-51 Composite Airframe, Brendon J. Townshend

Aerospace Engineering

This paper gives an overview of the progress that has been made in the design build of the X-51.  The X-51 is a composite scale replica of a P-51D fuselage integrated with a P-51H wing.  Issues with the airframe as well as current action items are discussed, as well as findings so far in preliminary design.