Mechanical Engineering Commons^™

Analysis And Modeling Of Depth-Of-Cut During End Milling Of Deposited Material, Haythem Gaja

Masters Theses

"This study addresses depth-of-cut detection and tool-workpiece engagement using an acoustic emission monitoring system during milling machining for a deposited material. Online detection of depth-of-cut presents many technical difficulties. Researchers have used various types of sensors and methods to assess the depth-of-cut and surface errors. Due to the strong correlation between acoustic emission and cutting depth during the depth end milling process, it is useful to forecast the depth-of-cut from the acoustic emission signal. This work used regression analysis to model and detect the depth-of-cut. The experiments were carried out on a Fadal vertical 5-Axis computer numerical control machine using …

Solar Powered Residential Hydrogen Fueling Station, Aanchal Shah

Masters Theses

"Interest towards the hydrogen fuel technology is increasing but its potential benefits will not be felt until hydrogen vehicles and the fueling infrastructure captures a substantial market share. Though there has been a rapid progress in the hydrogen fuel cell technology, a major challenge to the commercialization of fuel cell vehicles is the lack of hydrogen fueling infrastructure. The development of a commercial hydrogen fueling station is a challenge due to its high initial cost and safety concerns. Residential fueling stations provide an innovative solution to this issue since they also produce electricity and heat for the residential buildings in …

Development Of Hybrid Composite Bipolar Plates For Proton Exchange Membrane Fuel Cells, Nathaniel James Richie

Masters Theses

"Bipolar plates are one of the most expensive components of a PEM fuel cell and by far the heaviest. Bipolar plates are responsible for providing flow fields for reaction gases, acting as current collectors for electrons liberated during the chemical reaction inside the cell, and providing structural support for the fuel cell stack. Current PEM fuel cell bipolar plate technology is built on the use of sintered graphite which is costly and requires time-consuming machining. Furthermore, due to the brittle nature of graphite, plates must be made relatively thick which adds significant weight and volume to larger stacks, such as …

Effect Of Initial Conditions On Molecular Mixing In A High Schmidt-Number Rayleigh-Taylor Mixing Layer, Lakshmi Ayyappa Raghu Mutnuri

Masters Theses

"Characterizing molecular mixing in Rayleigh-Taylor instability (RTI) driven flows where the density and velocity fields are coupled is essential for developing exacting predictive models. Sensitivity of the Rayleigh Taylor mixing layer to initial conditions is a topic that is being explored extensively in interests of accurate turbulent mix model development and its direct consequence in various applications like design of inertial confinement fuel capsule and atmospheric modeling. As part of the current work, an experimental investigation of the effect of initial conditions on molecular mixing in a low Atwood number(~7.5 x 10⁻⁴), high Schmidt number(~1000), RTI driven mixing layer is …

Femtosecond And Nanosecond Laser Fabricated Substrate For Surface-Enhanced Raman Scattering, Adam Hamdorf

Masters Theses

"Surface-enhanced Raman scattering has many applications to chemical science, and shows great promise in the medical field because of its ability to provide "molecular fingerprinting" of probe molecules, whereby a material can be identified and potentially quantified. This is done by enhancing the normally weak Raman spectrum by many orders of magnitude with the use of fabricated substrates. It is therefore desirable to produce repeatable substrates with high enhancement factors for identification and quantification of samples. This thesis introduces a new method for generating such a substrate. By using femtosecond laser machining, gold sputtering, and nanosecond laser annealing, gold nanoparticles …

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 …

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 …

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 …

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 …

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 …

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 …

Maskless Additive Manufacturing Of Micro Structures By Laser Sintering Of Nanoparticles, Vivekram Ramanathan

Masters Theses

"The focus of this study was to investigate an alternate microfabrication process of sintering nanoparticles using a patterned laser light to generate two dimensional (2D) and three dimensional (3D) geometries. With trends of producing electronic and medical devices using cheaper and faster technologies, a new procedure was developed to deposit and bond miniature patterns of silver nanoparticles onto silicon substrates.

The process consists of spraying silver nanoparticles onto the substrate while a patterned or modulated laser beam is focused onto the sprayed nanoparticles. These nanoparticles exposed under the modulated laser light undergo partial melting or sintering and adhere to the …

Decentralized Coordinated Ilc System Design And Transient Growth Control Using Iteration-Varying Filter, Qing Liu

Masters Theses

"In automation control area, with the increasing demand in task complexity and high control precision, coordination between systems is required. There are mainly two types of coordinated systems, decentralized and centralized. This thesis is focused on a large array of coordinated systems, and the decentralized structure is preferred. To achieve high control precision in a coordinated system, many existing approaches may work, and in the system performing the repeating process, Iterative Learning Control (ILC) is a useful approach. Therefore, in this thesis, a decentralized coordinated ILC system is proposed and analyzed. The proposed control system is especially useful in coordinating …

Integration And Characterization Of An Electrical Storage System For A Hydrogen Fuel Cell Plug-In Hybrid Electric Vehicle, Edward Alexei Anculle Arauco

Masters Theses

"Hydrogen fuel cell hybrid vehicles are an advance technology that promises to solve the energy crisis in transportation and green houses emissions. Even more, Plug-in or extended range vehicles can add diversity in energy sources. Extended range vehicles have the capability to extract energy from the grid and hence reduce the cost of operation of the vehicle. EcoCAR: the NeXt Challenge is a Noth [sic] American competition with seventeen schools participating across North America. Missouri S&T is developing a Fuel Cell Plug-in Hybrid electric vehicle which has a large lithium-ion battery able to store 16 kWh. The fuel cell powertrain …

Validation Of Driving Simulator And Driver Perception Of Vehicle Mounted Attenuator Markings In Work Zones, Durga Raj Mathur

Masters Theses

"This research work sought to validate the driving simulator at Missouri University of Science and Technology and to evaluate the vehicle mounted attenuator (VMA) markings for various times of day. For comprehensive validation of the driving simulator, a framework is proposed which is demonstrated using a fixed-base driving simulator. Objective and subjective evaluations were conducted, and validation of the driving simulator was performed at specific locations and along the highway. Field data were collected for a partial lane closure using a global positioning system (GPS) along the work zone and supplemented with video recordings of traffic data at specific locations …

Synthesis And Characterization Of Microspheres For Controlled Release, Gurpartap Singh Sandhu

Masters Theses

"Synthetic hydroxyapatite (HAp, (Ca₁₀(PO₄)₆(OH)₂) has always been of interest in medical applications because of its similarities to inorganic bone matrix. It has been used in biomedical applications for bone repair and substitution due to its biocompatibility. However, there are some differences in the stoichiometry, composition, and mechanical properties of human bone as compared to pure HAP. HAp particles have been successfully used as drug delivery carriers which deliver the drug to the affected part of the body and the remaining apatite gets degraded by the physiological processes in the body. In the present work, emphasis was on developing mechanically stronger …

Quantification Of Product Color Preference In A Utility Function, Hannah L. Turner

Masters Theses

"Currently, many marketing and engineering tools exist to help a designer optimize quantitative attributes of a product, such as height, weight, volume, or cost. However, these methods cannot effectively take into consideration aesthetic attributes of a product, or any other attributes for which there is no understood functional relationship between the attribute's potential values and the consumer's preference. This research has begun the work of developing this necessary functional relationship for the aesthetic attribute of color and has created a methodology for further research. To do this, colors were represented by their red, green, and blue light components, and preference …

Energy Expenditure Analysis Of Redesigned Mechanical Assists For Medium Girder Bridge, Karthik Kumar

Masters Theses

"U.S. Army bridge crew soldiers perform tough manual material handling (MMH) tasks during the assembly of a Medium Girder Bridge (MGB). The bridge parts are very heavy and are manually lifted from pallets, carried to the construction site and assembled with other bridge parts. An energy expenditure study on the soldiers handling the bridge parts revealed that the energy expenditure rate of the soldiers exceeds the NIOSH prescribed safety limit of 3.5 Kcal/min. This leads to high risk of musculoskeletal disorders. The study deals with modifying the first redesign of mechanical assists for medium girder bridge (MGB) and studying the …

Simulation Of Pem Fuel Cells: Validation Of Model And Incorporation Of Humidity Dynamics, Steven Francis Rodgers

Masters Theses

"Fuel cell technologies have been receiving increased attention by industry and researchers due to growing societal and inevitable economic pressures to find an alternative for fossil fuels. At the forefront of this is the demand for fuel cell models: models to elucidate fundamental physical phenomena underlying fuel cell function and models that are not computationally demanding yet reasonably accurate to allow designers to incorporate fuel cells into consumer products. One of the latter type has recently been developed based on a software package that is already in widespread use in the automotive industry for the simulation of mechanical, thermal, electrical, …

Finite Element Analysis And Fatigue Test On The Bicuspids To Support Theory Of Abfraction, Madhuchandra Mahadevaswamy

Masters Theses

"Abfraction is a small crack or notch found at the cervical areas of a teeth due to the loss of enamel tissues in the teeth. Proposed explanations for are that it is caused by toothbrush abrasion, acid erosion, and the mechanical forces applied on the teeth due to chewing, biting, tongue activity. There is disagreement among dentists as to the primary causes of abfraction. Some dentists believe that abfraction is caused by toothbrush abrasion and erosion due to acidic food and drinks. Other dentists believe that tensile and compressive forces acting on the teeth from non-axial, cyclical loading over an …

Evaluation Of Metal Detection Audio Alert Signals Of An/Pss-14 By Means Of Real Time Visualization, Sandesh Srikantaiah Chandrashekar

Masters Theses

"The sweep arm of the AN/PSS-14 Landmine Detector attached to an independent visualization device will transform the AN/PSS-14 into a hand-held data acquisition system for conversion of real time MD and GPR audio alert signals into captured visual trace displays on an on-board PDA computer screen so that momentary sounds of millisecond durations can be captured and displayed for visual scrutiny and interpretation by analytical on-board data processing procedures. This is a part of a two-man team that is developing a visual data adapter for the AN/PSS-14 Landmine Detector where the current thesis is concentrating only on MD audio alerts. …

A Real-Time Visualization Of An/Pss-14 Audio Alert Signals For Land Mine Detection Validation, Nitin Kolekar

Masters Theses

"The central idea of the current research is visualization of audio alerts from AN/PSS-14. A visualization device connected to the arm of PSS-14 will show real-time display of MD and GPR Audio Alert signals from PSS-14. This visualization device displays both amplitude-time and spectral frequency-time formats of the signals. The latter format achieves visual separation of combined, simultaneous, MD and GPR alerts. The joint occurrence of MD and GPR signals in a specific time window confirms the presence of landmine. This window is defined by the time of occurrence of MD peak and time of occurrence GPR diffraction from onset …

Thermodynamic Based Modeling For Nonlinear Control Of Combustion Phasing In Hcci Engines, Joshua Bradley Bettis

Masters Theses

"Low temperature combustion modes, such as Homogeneous Charge Compression Ignition (HCCI), represent a promising means to increase the efficiency and significantly reduce the emissions of internal combustion engines. Implementation and control are difficult, however, due to the lack of an external combustion trigger. This thesis outlines a nonlinear control-oriented model of a single cylinder HCCI engine, which is physically based on a five state thermodynamic cycle. This model is aimed at capturing the behavior of an engine which utilizes fully vaporized gasoline-type fuels, exhaust gas recirculation and intake air heating in order to achieve HCCI operation. The onset of combustion, …

Automation Of Cad Model Based Assembly Simulations Using Motion Capture, Anup Madhav Vader

Masters Theses

"The manufacturing industry often uses text and video as a supplement for worker training procedures. Unfortunately, text is often difficult to follow and video lends itself to occlusion issues. CAD based animations of assembly operations can overcome these shortcomings while offering greater potential for operations analysis and simulation flexibility. However, creating such CAD based training simulations manually is a time intensive task and many a times fail to reveal the practical assembly issues faced in the real world. Thus, it is highly beneficial to be able to automate these simulations using motion capture from a physical environment. This thesis research …