Engineering Commons^™

Thermodynamic And Chemical Kinetic Coupled Modeling For The Determination Of Cyclic Combustion Phasing In Hcci Engines, Krishawn Michele Goodwin

Masters Theses

"Homogeneous charge compression ignition (HCCI) is a low temperature combustion mode that contains great potential for decreasing emissions while increasing efficiency in internal combustion engines. The limitation is in that it is inherently difficult to control based on the lack of an external combustion trigger. This thesis outlines the potential of using the combustion residual species of carbon monoxide as a method of controlling the location of combustion by using data from a computer model. The model is a nonlinear five-state thermodynamic model that is coupled with a skeletal chemical kinetic model for PRF96. The model computes the amount of …

Parameter Determination And Experimental Validation Of A Wire Feed Additive Manufacturing Model, Kannan Suresh Kumar

Masters Theses

“Laser metal deposition is an additive manufacturing method with great scope and robustness. The wire fed additive manufacturing method has great opportunities in space applications and other zero gravity manufacturing processes. Process parameters play an important role in controlling the complex phenomenon and obtaining an ideal manufactured part. These parameters can be efficiently determined using simulation tools which are highly essential in visualizing real world experiments, therefore saving time and experimental costs. The objective of this study is to develop a transient 3D model of laser aided wire feed metal deposition which realizes the heat transfer and fluid flow behavior …

Design Studies Of Infrastructural Development For Applications Of Hydrogen Energy Technologies, Yousif M. H. Hamad

Doctoral Dissertations

"Countries around the world are trying to reduce their energy consumption, fossil fuel usage, and greenhouse gas (GHG) emissions. According to the International Energy Outlook 2012 released by the U.S. Energy Information Administration (EIA), the estimated fuel economy and greenhouse gas emissions standards proposed for light-duty vehicles for model years 2017-2025 has an increase of 44% in fuel economy and a reduction of 34% in GHG emissions. The use of alternative fuel vehicles and renewable energy sources are, therefore, inevitable toward achieving this goal. Biogas has untapped potential as an alternative energy source. This immediately available resource would allow countries …

Freeze-Form Extrusion Fabrication Of Boron Carbide, Aaron Scott Thornton

Masters Theses

"Boron carbide is a safe, alternative to beryllium as a material for aerospace structures since it is also light-weight and exhibits high strength. This paper discusses a study of the Freeze-form Extrusion Fabrication (FEF) process to fabricate parts from boron carbide. Process parameters and hardware were modified to fabricate boron carbide specimens free of printed defects. Four-point bending tests were performed to measure the flexural strength of fabricated specimens. Observations of the presence of voids caused by ice crystals in fabricated parts led to further development and characterization of the boron carbide paste used with the FEF process. Additives were …

Emission And Energy Analysis Of Self-Sufficient Biomass Power Plant To Achieve Near Net Zero Co₂ Emission, Baburaj Kanagarajan

Masters Theses

"The use of biomass to fuel power plants is considered by many to be a carbon neutral solution to carbon dioxide emissions. One objection to this method of power generation is the gasoline or diesel spent in the transportation and feedstock production, which is a major contributor to carbon emission. In addition, costs associated with the transportation of the biomass fuels are also a major limiting. This work investigates the use of a hybrid farming facility as a means of distributed generation combined. A model that incorporates a small scale biomass power facility located within a farming facility is examined. …

Combustion And Pollutant Characteristics Of Ic Engines Fueled With Hydrogen And Diesel/Hydrogen Mixtures Using 3d Computations With Detailed Chemical Kinetics, Hassan A. Khairallah

Doctoral Dissertations

In order to develop design guidelines for optimum operations of internal combustion engines fueled with alternative fuels, a comprehensive understanding combustion behavior and the pollutant formation inside the cylinder are needed. The first part of this thesis aimed to numerically study the engine performance and in-cylinder pollutant formation in a spark ignition engine fueled with hydrogen. Advanced simulations were performed using multi- dimensional software AVL FIRE coupled with CHEMKIN. The detailed chemical reactions with 29 steps of hydrogen oxidation with additional nitrogen oxidation reactions were also employed. Formation rates of nitrogen oxides (NOx) within the engine were accurately predicted using …

Experimental And Computational Analysis Of Thermosyphon Based Water Heaters, Siddarth Ashokkumar

Masters Theses

"Storage type electric water heaters are one of the most commonly found type of heaters in households today. Due to energy costs and limited generation capacity, there is a need for improving the efficiency of such water heaters. The efficiency of water heating systems have impact both at the household and at the national level, because of their sheer numbers. Efficient water heaters lead to lower utility bills for the consumer and also reduced demand on the grid supplying electrical power to such households. This leads to a reduction in the amount of fuel used in generating electrical power and …

Numerical Study Of Upstream And Downstream Regions Of One Dimensional Detonation Wave In A Dusty Gas Medium, Shubhadeep Banik

Masters Theses

"In detonative combustion very high temperatures are attained by the burned gases. As a result, a large amount of thermal energy is produced during the combustion process. This heat can affect the state of the unburned fuel through radiation of heat from the burned gases. In this study a one-dimensional model was deemed appropriate to gain insight into the fundamental structure of the detonation wave. In this model, the detonation wave divides the fluid stream into an upstream region, consisting of fuel and oxidant, and a downstream region, consisting of burned gases. A set of computer programs, some developed during …

American Sign Language Alphabet Recognition Using Microsoft Kinect, Cao Dong

Masters Theses

"American Sign Language (ASL) fingerspelling recognition using marker-less vision sensors is a challenging task due to the complexity of ASL signs, self-occlusion of the hand, and limited resolution of the sensors. This thesis describes a new method for ASL fingerspelling recognition using a low-cost vision camera, which is Microsoft's Kinect. A segmented hand configuration is first obtained by using a depth contrast feature based per-pixel classification algorithm. Then, a hierarchical mode-finding method is developed and implemented to localize hand joint positions under kinematic constraints. Finally, a Random Decision Forest (RDF) classifier is built to recognize ASL signs according to the …

Pipeline Leak Detection, Marcia Golmohamadi

Masters Theses

"In the present research two techniques are applied for leak detection in pipelines. The first method is a hardware-based technique which uses ultrasonic wave's emission for pipeline inspection. Ultrasonic waves are propagated in the pipe walls and reflected signal from leakage will be used for pipe analysis. Several Pipes with various dimensions and characteristics are modeled by finite element method using ANSYS. Second order longitudinal modes of ultrasonic waves are emitted in their walls. For this purpose, excited frequency is calculated such that it excites the second order longitude mode. In order to investigate the behavior of emitted wave in …

Thermographic Investigation Of Laser Metal Deposition, Sreekar Karnati

Masters Theses

"Laser metal deposition as an additive manufacturing technique has been proven to possess the capability for fabricating complex, intricate geometries and excellent material properties through material deposition. Accurate manufacture of such geometric features would require precise control over the material deposition process. The need of the hour are process monitoring and analyses mechanisms that are crucial in ascertaining the occurrence of the intended actions during deposition while also serving as effective learning tools. The current work involved developing and incorporating an Infra-Red (IR) camera as a process monitoring tool for laser metal deposition. Using the IR camera the thermal dynamics …

An Experimental Study Of Fabrication Temperature Effect On Aqueous Extrusion Freeform Fabrication, Jie Li

Masters Theses

"In order to understand the effect of fabrication temperature, a computer controlled 3-D gantry system was used to extrude aqueous alumina paste using Extrusion Freeform Fabrication. The system includes a temperature control subsystem that allows for fabrication of components below the paste's freezing temperature in the range of -10⁰C to -30⁰C and a hot plate with temperature in the range of 20⁰C to 80⁰C inside a room temperature chamber. Comparisons in terms of relative density, mechanical properties, part accuracy and minimum deposition angle were performed by Extrusion Freeform Fabrication at 40⁰C plate temperature inside a room temperature chamber and at …

Laser Surface And Sub-Surface Repair During Metal Additive Manufacturing, Prudvi Teja Ravi

Masters Theses

"This study examines the use of laser surface treatment to repair surface and subsurface defects. Numerical analysis was performed on laser surface melting using Gaussian heat distribution equations to analyze the depth of the melt pool created by the phenomena. Concurrently, a process map was developed with a planned set of experiments by varying the ranges of laser power and travel speed to determine the dimensions of the melt pool across the gamut. The data generated from both the process studies and the numerical analysis was then used to determine the ideal operating ranges of the process parameters to repair …

Spatial And Temporal Modulation Of Heat Source Using Light Modulator For Advanced Thermography, Arvindvivek Ravichandran

Masters Theses

"Thermography is a Non-Destructive Testing (NDT) method that has found increasing use in industry and research. It has the advantages of being non-contact and be able to interrogate a large surface simultaneously. Active thermography using flash lamps as heat source has been demonstrated for identifying blind holes and delamination in composites. Despite these advancements, active thermographic approach fails to defects like cracks. Under uniform illumination heat flow is predominantly 1D and can easily circumvent a narrow feature. This can be overcome by using a focused light/laser source onto the surface to impose a 3D heat flux. The disadvantage is that …

Experimental And Computational Evaluation Of Water Management And Performance Of A Bio-Inspired Pem Fuel Cell In Comparison To A Conventional Flow Field, Venkatanaga Bhaskar Prakash Saripella

Masters Theses

"Fuel cells are being increasingly used in various stationary and transportation power applications due to their higher energy efficiency and lower pollution. Flow field design in Proton Exchange Membrane (PEM) fuel cells is a major area of research for performance improvement. Bio-inspired flow field designs have significant potential for increased performance by effective distribution of reactants with better water management capabilities. In this study, a bio-inspired flow field design, formulated using Murray's law and mimicking a typical leaf venation pattern, is experimentally and computationally investigated in comparison to a conventional single serpentine design. Experiments are conducted using a special transparent …

A Force Feedback Haptic Interface For Atomic Force Microscopy, Abdulmohsen Alabdulmuhsin

Masters Theses

"Integrating a force feedback haptic device with atomic force microscopy (AFM) improves the capability to investigate and manipulate the objects on a micro- and nanoscale surface. The haptic device provides the researcher with a sense of touch and movement by changing the position of the stylus or amount of force on it. The developed system's concept is to provide the user a sense and feel and control of the AFM probe at the nanoscale. By positing the haptic stylus, the user generates reference to commands to the AFM probe. In turn, forces experienced by the probe are communicated to the …

Mechanistic Modeling Of Cutting Forces In Wavy-Edge Bull-Nose Helical End-Milling Of Inconel 718 Under Different Cooling-Lubrication Strategies, Abdulhakim Ali Sultan

Doctoral Dissertations

“This research presents the results of the development of a mechanistic cutting force prediction model for the wavy-edge bull-nose helical endmill (WEBNHE). The mechanistic model was developed to predict cutting force components and the resultant cutting force in high-speed end-milling of Inconel 718 under two cooling strategies: emulsion and Minimum Quantity Lubrication (MQL). The effects of the cooling strategies are incorporated into the mechanistic model through six cutting force coefficients (K_tc, K_rc, K_ac), and edge force coefficients (K_te, K_re, K_ae), which have been experimentally identified in a separate …

Investigation Of Effect Of Process Parameters On Multilayer Builds By Direct Metal Deposition, Tarak Amine

Doctoral Dissertations

"Multilayer direct laser deposition (DLD) is a fabrication process through which parts are fabricated by creating a molten pool into which metal powder is injected as. During fabrication, complex thermal activity occurs in different regions of the build; for example, newly deposited layers will reheat previously deposited layers. The objective of this study was to provide insight into the thermal activity that occurs during the DLD process. This work focused on the effect of the deposition parameters of deposited layers on the microstructure and mechanical properties of the previously deposited layers. Varying the parameters was shown to produce different effects …

On The Design And Analysis Of Compliant Mechanisms Using The Pseudo-Rigid-Body Model Concept, Sushrut Gangadhar Bapat

Doctoral Dissertations

"The pseudo-rigid-body model (PRBM) concept, developed for the analysis and design of large-deflection flexible members, has proved over time to be a simple, efficient and accurate tool for the synthesis, analysis and design of compliant mechanisms. This dissertation investigates a variety of compliant mechanism analysis and design problems using the PRBM concept and assists in further advancement of the implementation of the PRBMs. The dissertation begins with the development of a PRBM for a fixed-guided compliant beam with one inflection point in the deformed state. This research investigation advances the concept of characteristic deflection domain to a new synthesis framework …

Energy Management In Electric Vehicles: Development And Validation Of An Optimal Driving Strategy, Warren Santiago Vaz

Doctoral Dissertations

Electric vehicles (EVs) are a promising alternative energy mode of transportation for the future. However, due to the limited range and relatively long charging time, it is important to use the stored battery energy in the most optimal manner possible. Existing research has focused on improvements to the hardware or improvements to the energy management strategy (EMS). However, EV drivers may adopt a driving strategy that causes the EMS to operate the EV hardware in inefficient regimes just to fulfil the driver demand. The present study develops an optimal driving strategy to help an EV driver choose a driving strategy …

Local Alternative Sources For Cogeneration Combined Heat And Power System, Abdulhakim Amer Agll

Doctoral Dissertations

"Global demand for energy continues to grow while countries around the globe race to reduce their reliance on fossil fuels and greenhouse gas emissions by implementing policy measures and advancing technology. Sustainability has become an important issue in transportation and infrastructure development projects. While several agencies are trying to incorporate a range of sustainability measures in their goals and missions, only a few planning agencies have been able to implement these policies and they are far from perfect. The low rate of success in implementing sustainable policies is primarily due to incomplete understanding of the system and the interaction between …

Selective Laser Sintering Of Bioactive Glass Scaffolds And Their Biological Assessment For Bone Repair, Krishna C. R. Kolan

Doctoral Dissertations

"Bone scaffold fabrication using powder-bed based additive manufacturing techniques, like the selective laser sintering (SLS) process, provides control over pore interconnectivity, pore geometry, and the overall shape of the scaffold, which aids in repairing different regions of the bone. The main objectives of this dissertation were to develop bioactive glass (BG) scaffolds using the SLS process and evaluate the scaffolds for their effectiveness in bone repair both in vitro and in vivo. 13-93 glass, a silicate based BG, and 13-93B3 glass, a borate based BG, are designed to accelerate the body's natural ability to heal itself and are used …

Freeform Extrusion Fabrication Of Titanium Fiber Reinforced 13-93 Bioactive Glass Scaffolds, Albin Thomas

Masters Theses

"Although implants made with bioactive glass have shown promising results for bone repair, their application in repairing load-bearing long bones is limited due to their poor mechanical properties as compared to human bones. This thesis study is on freeform extrusion fabrication of silicate based 13-93 bioactive glass scaffolds reinforced with titanium fibers. A composite paste was prepared with 13-93 bioactive glass filled with titanium fibers (~16 µm in diameter and aspect ratio of ~250) having 0.1 to 0.4 vol. % of the bioactive glass scaffold. This paste was then filled into a syringe manually, and then extruded through a nozzle …

Generation And Validation Of Optimal Topologies For Solid Freeform Fabrication, Purnajyoti Bhaumik

Masters Theses

"The study of fabricating topologically optimized parts is presented hereafter. The mapping of topology optimization results for Standard Tessellation Language (STL) writing would enable the solid freeform fabrication of lightweight mechanisms. Aerospace leaders such as NASA, Boeing, Airbus, European Aeronautic Defense And Space Company (EADS), and GE Aero invest in topology optimization research for the production of lightweight materials. Certain concepts such as microstructural homogenization, discretization, and mapping are reviewed and presented in the context of topology optimization. Future biomedical applications of solid freeform fabrication such as organ printing stand to save millions of lives through the robust development of …

System Integration Of Hydrogen Energy Technologies Using Renewable Energy Resources, Tarek A Mohammed Hamad

Doctoral Dissertations

"The objective of this work has two major tasks that investigation the use of CHHP system at the Missouri University of Science and Technology (Missouri S&T) campus and studying solid waste as renewable source of energy: current and future possibility in Libya. Task one has three major topics. In Topic I, Design of Combined Hydrogen, Heat and Power (CHHP) system for the campus using local resources and treated biogas can be used to generate CHHP using a Molten Carbonate Fuel Cell (MCFC). In Topic II, hydrogen recovery and cleaning system, Heat recovery and electric power usage, hydrogen compression, storage, and …

Investigation Of Robust Optimization And Evidence Theory With Stochastic Expansions For Aerospace Applications Under Mixed Uncertainty, Harsheel R. Shah

Doctoral Dissertations

One of the primary objectives of this research is to develop a method to model and propagate mixed (aleatory and epistemic) uncertainty in aerospace simulations using DSTE. In order to avoid excessive computational cost associated with large scale applications and the evaluation of Dempster Shafer structures, stochastic expansions are implemented for efficient UQ. The mixed UQ with DSTE approach was demonstrated on an analytical example and high fidelity computational fluid dynamics (CFD) study of transonic flow over a RAE 2822 airfoil.

Another objective is to devise a DSTE based performance assessment framework through the use of quantification of margins and …

Stochastic Interdigitation As A Toughening Mechanism At The Interface Between Tendon And Bone, Y. Hu, Victor Birman, A. Demyier-Black, A. G. Schwartz, S. Thomopoulos, G. M. Genin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

On The Design Of A Nearly Constant-Force Modular Device Based On A Compliant Slider Mechanism, Krutika Karthik

Masters Theses

"Compliant mechanisms derive some or all of their mobility from the deflection of their flexible members. A pseudo-rigid-body model (PRBM) provides a simple and efficient way of modeling and analyzing large deflections in compliant mechanisms. In this work, a partially compliant slider mechanism, composed of rigid and compliant segments as well as rigid-body revolute and prismatic pairs, is considered. In recent works, such mechanisms have been dimensionally synthesized to produce substantially constant-force output over a finite range of input link displacement in an in-line PRBM of a compliant slider mechanism. In this thesis, the current practice of using partially compliant …

On The Dynamic Analysis Of Compliant Mechanisms Based On The Pseudo-Rigid-Body Model, Andrew Christian

Masters Theses

"Compliant mechanisms derive some or all of their mobility from the deflection of flexible members. A pseudo-rigid-body model (PRBM) provides an elegant and simple way of modeling and analyzing traditionally nonlinear large-deflection problems pertaining to compliant mechanisms. In this work, several aspects pertainting to the dynamics of compliant mechanisms are considered. First, dynamic models are derived to predict not only the natural frequency of the large-deflection systems, but also the transient response, using the PRBM approach. A unique multi-stage damping model is developed to determine the transient response in free vibration. Recent works have neglected to consider the transient response …

Performance Metrics For Powder Feeder Systems In Additive Manufacturing, Venkata Sivaram Bitragunta

Masters Theses

"In blown powder Direct Metal Deposition (DMD) process, parts are built by adding metal powder on the melt pool created by the laser system. At low feed rates powder feeder systems have perturbations. The study focused on relationship between the perturbation frequencies by inherent powder feeder designs and its impact on deposition quality. Performance metric determine the relation between perturbations in the powder flow and quality of the deposit. To determine performance metric, various powder feeder designs were analyzed. Perturbation frequencies were introduced to the disk feeder design. The quality of the deposit was determined by the surface roughness of …