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Title: MODELING THE IMPACT OF NATURAL GAS VARIATION ON COMBUSTION IN A DUAL FUEL ENGINE
Creator: Hulbert, Matthew Calvin
Date: 2017, 2017-07
Description: The desire to meet rising energy demands while simultaneously adhering to stringent climate policies have propelled several advanced...
Show moreThe desire to meet rising energy demands while simultaneously adhering to stringent climate policies have propelled several advanced combustion technologies. The utilization of alternative fuels in internal combustion engines is a relevant solution to the immediate problems facing the transportation sector. Natural gas (NG) is an attractive alternative as it is economically and environmentally versatile, geographically diverse, and has clean-burning qualities which when coupled with dual fuel technologies has shown significant positive impacts on combustion characteristics. The present work describes the setup of an experimental test cell that contains a modern 2.0-liter 4-cylinder turbocharged direct-injected diesel engine that will be modified for dual fuel capability. The initial stages of a computationally efficient simulation model that represents the experimental engine are also presented and a discussion on the model’s development ensues. A dual fuel simulation model was created and calibrated against experimental data obtained from a heavy-duty 6-cylinder duel fuel engine. The objective of this work is to assess the affects different NG compositions have on the combustion process. Natural gas has shown to vary significantly, depending on where the fuel is acquired. The results show that methane content plays a significant role on combustion. As methane content increases, start of combustion (SOC) shifts and peak cylinder pressure decreases. The premixed combustion phase is shown to increase with decreasing methane content, while the mixing-controlled combustion phase decreases. Nitrogen oxides (NOx), carbon monoxide (CO), and carbon dioxide (CO2) emissions have demonstrated to be dependent on methane content. NG compositions with low methane content show increased amounts of CO2 emissions while high methane content shows a decrease in nitric oxide (NO) emissions.
M.S. in Mechanical and Aerospace Engineering, July 2017
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Title: DEVELOPMENT OF ADVANCED PACKAGING, FABRICATION AND RELIABILITY METHODS FOR SUBMINIATURE IMPLANTABLE NEURAL PROSTHESES
Creator: Kim, Taehyung
Date: 2011-08, 2011-07
Description: The main purpose of the present thesis is to study the critical reliability issues of polymeric encapsulated electronic devices for visual...
Show moreThe main purpose of the present thesis is to study the critical reliability issues of polymeric encapsulated electronic devices for visual prosthesis. Visual prosthesis has been compatibly studied over twenty years in many professional research labs. The electric design of circuit for the visual prosthesis has been well studied so far. However, the device packaging design and reliability have been not studied extensively. In particular, failure analysis and reliability using non-hermetic packaging for long lifetime visual prosthesis have been poorly studied. The first step of the research for this thesis was to create a mechanical design of a visual prosthesis prototype. The prototype device was created by fabricate a multi-layer structure consisting of electrodes, substrate, and integrated circuit chip with silicone encapsulated packaging. The interconnection between the chip and electrodes used Au wire and Al bonding pad. The prototype devices were tested in a liquid water. This water environment is not a common reliability test for commercial electronic packaging. Relative humidity testing is a common and widely used testing methods, but the visual prosthesis device cannot be applied to gas phase relative humidity testing due to the environment condition. Water absorption in polymeric material in the liquid water is higher than in the vapor water. After water penetrated interconnection interface, the Au-Al intermetallic compound becomes oxidized and generates bonding die open failure. From these unusual testing results, we were conformed the failure mechanism and predicted the lifetime using Au-Al imtermetallic growth pattern and oxidation. Additional discussions include transition metal ions in CSF to expect the other failure mechanisms. Wafer and packaging level xiii failure mechanisms by Cu and Fe ions are also discussed in this thesis. The end of this thesis discuss possible fabrication processing to protect overall external environment effects for polymeric packaging visual prosthesis. Overall this thesis study, which uses polymeric packaging electronic devices for bio-implant research, concluded that devices may not make good reliability devices in the CSF environment. The corrosion, oxidation and metallization on or in metal surfaces and interconnection interfaces should continually be studied to produce longer lasting electronic devices over 30 years. The reliability of the visual prosthesis has not been well studied in any other professional research labs, so this thesis may give or address some initial guidelines to help save time for the project decision in the future to develop advanced hermetic packaging for bioimplantable electronic devices.
Ph.D. in Materials Science and Engineering, July 2011
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Title: BLADE PITCH OPTIMIZATION METHODS FOR VERTICAL-AXIS WIND TURBINES
Creator: Kozak, Peter
Date: 2016, 2016-07
Description: Vertical-axis wind turbines (VAWTs) offer an inherently simpler design than horizontal-axis machines, while their lower blade speed mitigates...
Show moreVertical-axis wind turbines (VAWTs) offer an inherently simpler design than horizontal-axis machines, while their lower blade speed mitigates safety and noise concerns, potentially allowing for installation closer to populated and ecologically sensitive areas. While VAWTs do offer significant operational advantages, develop- ment has been hampered by the difficulty of modeling the aerodynamics involved, further complicated by their rotating geometry. This thesis presents results from a simulation of a baseline VAWT computed using Star-CCM+, a commercial nite volume (FVM) code. VAWT aerodynamics are shown to be dominated at low tip- speed ratios by dynamic stall phenomena and at high tip-speed ratios by wake-blade interactions. Several optimization techniques have been developed for the adjustment of blade pitch based on finite-volume simulations and streamtube models. The effectiveness of the optimization procedure is evaluated and the basic architecture for a feedback control system is proposed. Implementation of variable blade pitch is shown to increase a baseline turbine's power output between 40%-100%, depending on the optimization technique, improving the turbine's competitiveness when compared with a commercially-available horizontal-axis turbine.
Ph.D. in Aerospace and Mechanical Engineering, July 2016
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Title: EFFECTS OF UNSTEADY AERODYNAMICS ON VERTICAL-AXIS WIND TURBINE PERFORMANCE
Creator: Kozak, Peter
Date: 2014, 2014-05
Description: Vertical-axis wind turbines (VAWTs) o er an inherently simpler design than horizontal-axis machines, while their lower blade speed mitigates...
Show moreVertical-axis wind turbines (VAWTs) o er an inherently simpler design than horizontal-axis machines, while their lower blade speed mitigates safety and noise concerns. As a result, VAWTs can be used to open up more populated areas for large-scale wind energy development. While vertical-axis turbines do o er signi cant operational advantages, development has been hampered by the di culty of mod- eling the aerodynamics involved, along with their rotating geometry. This thesis presents results from a simulation of a baseline VAWT computed using Star-CCM+, a commercial nite volume (FVM) code. Overset grid techniques are used to model the VAWT's complex and moving geometry. VAWT aerodynamics are shown to be dominated at low tip-speed ratios by dynamic stall phenomena and at high tip-speed ratios by wake-blade interactions, using ow visualization and blade angle of attack. An iterative procedure to optimize the VAWT's geometry is developed using blade pitch to mitigate the adverse e ects of dynamic stall for a tip-speed ratio of 2.0 case. Relying on both a constant blade pitch o set as well as a variable blade pitch as a function of azimuthal angle, power output was shown to be increased by 17% and 38%, respectively, compared to the baseline case. Emphasis is placed on the modeling techniques used in the FVM simulation and the optimization process.
M.S. in Mechanical and Aerospace Engineering, May 2014
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Title: AN OPTIMIZATION OF MANUFACTURING PROCESS SELECTION THROUGH COSTING AND SYSTEMATIC ANALYSIS
Creator: Klima, Kevin
Date: 2017, 2017-05
Description: In order for any company to remain competitive, there is a constant push to cut costs while keeping customers satisfied by providing quality,...
Show moreIn order for any company to remain competitive, there is a constant push to cut costs while keeping customers satisfied by providing quality, robust products. While current methods for predicting the most cost effective manufacturing process have proven to offer a significant amount of utility for design engineers, the issue remains that for a cost estimation to be truly accurate, the component has to be completely or nearly completely designed, which could require a significant amount of upfront development time. The goal was to develop a design tool to predict the most cost effective process to manufacture a new component based solely on already available historical data and basic knowledge of the design requirements of the new part. This study focused on steel components that could be manufactured either as a fabrication or as a casting. Two real-world applications were studied from two separate industries, with each application being designed with each process. Common cost estimation techniques were used to develop models for predicting the cost for each component to offer insight for how the cost would be expected to vary with quantity. As a means of ensuring robustness and that each competing model was structurally equivalent, each model had to pass critical exceptional and fatigue load cases in FEA while also meeting predefined success criteria. Using the results from the structural analysis and cost estimation, a design tool was developed as a means of objectively predicting how a component with similar application requirements would most cost effectively be manufactured based on the desired quantity of parts that needed to be produced. By using historical information of similar components that have the possibility of being manufactured in more than one way, more effective and systematic decision making for how a new component should be manufactured was shown to be possible. A third, independent case study was also selected as a real world example from industry as a means of validating and assessing the sensitivity of the weighting used in the development of the design tool. This was used to further refine the tool for the use in analyzing future components.
M.S. in Manufacturing Engineering, May 2017
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Title: Manufacture and uses of steel pipes
Creator: Harvey, James S., Jr.
Date: 2009, 1914
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/manufactureuseso00harv
Thesis (B.S.)--Armour Institute of Technology, 1914 Bibliography: leaf 82 B.S. in...
Show morehttp://www.archive.org/details/manufactureuseso00harv
Thesis (B.S.)--Armour Institute of Technology, 1914 Bibliography: leaf 82 B.S. in Mechanical Engineering, 1914
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Title: Design for power plant
Creator: Henwood, P. E.
Date: 2009, 1910
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/designforpowerpl00henw
Thesis (B.S.)--Armour Institute of Technology

Title: The design and equipment of a metallographic polishing machine
Creator: Hallett, John A.
Date: 2009, 1921
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/designequipmento00hall
Thesis (B.S.)--Armour Institute of Technology; Bibliography: leaf 18

Title: ADVANCES IN VEHICLE-TERRAIN INTERACTION MODELING FOR SMALL, RIGID-WHEELED VEHICLES OPERATING ON DEFORMABLE TERRAIN
Creator: Meirion-griffith, Gareth
Date: 2012-04-22, 2012-05
Description: This thesis presents advances in the eld of terramechanics, the study of ve- hicle mobility performance, for small, rigid-wheeled vehicles...
Show moreThis thesis presents advances in the eld of terramechanics, the study of ve- hicle mobility performance, for small, rigid-wheeled vehicles operating on deformable terrain. Speci cally, the thesis proposes new models for vehicle performance model- ing through the development of novel pressure-sinkage equations. The semi-empirical equations of terramechanics, rst developed by Bekker in the 1950s, couple vehicle mobility systems and terrain geotechnical properties to yield an understanding of the manner in which traction is developed o -road. This is important because on de- formable terrain mobility is often limited not by the vehicle's torque or power, but by the strength of the terrain and its ability to support locomotion. Classical terramechanics models have proven to be instrumental in the design, modeling, and operation of large, man-driven vehicles for applications such as agri- cultural, military, and commercial transport. However, these models are not appro- priate for vehicles with wheels less than approximately 50 cm in diameter [MGS11a] [SMGSM08] [RBC02]. This is a critical problem because of the increasing prolifer- ation of small, robotic vehicles. In particular, space agencies such as the National Aeronautics and Space Administration (NASA), the Japanese Aerospace Exploration Agency (JAXA), and the European Space Agency (ESA) have shown great interest in the application of terramechanics to planetary exploration rover mobility. At the inception of the author's research, several independent sources had noted the limited accuracy of classical terramechanics models for small-wheeled vehi- cles. However, an understanding of the cause of these inaccuracies was absent. This thesis provides an understanding of these inaccuracies, their cause, and a solution. Using laboratory experiments, fi eld test data, theoretical development, and vehicle simulation, this thesis proposes a modi fied terramechanics framework for predicting small, rigid-wheel traction.
Ph.D. in Mechanical and Aerospace Engineering, May 2012
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Title: RATE AND TEMPERATURE DEPENDENT MECHANICAL BEHAVIOR AND MODELING OF AL-CU ALLOY SYSTEM
Creator: Tran, Henry
Date: 2011-12-19, 2011-12
Description: Deformation of materials in army applications such as fragment impact, projectile penetration and air blast/shock waves involves high strain...
Show moreDeformation of materials in army applications such as fragment impact, projectile penetration and air blast/shock waves involves high strain rates, large strains, high pressures and rapid changes in temperature, where overall performance ultimately depends on the evolution of flow stress, failure initiation and propagation, generally in the form of adiabatic shear banding (ASB), under these severe loading conditions. Some of 2XXX series aluminum-copper (Al-Cu) alloys such as Al 2519-T87 have been successfully used in Lightweight Armored Vehicles in the U.S. Army because of their good ballistic properties. More recently, an Al-Cu-Mg-Ag alloy designated as Al 2139-T8 has emerged in 2004 as a strong candidate in damage critical applications with higher strength and high-strain-rate performance than its predecessors. Its better ballistic performance is believed to be due to the underlying microstructure. The objective of this study is to investigate mechanical and deformation behavior of Al-Cu material system to develop a fundamental understanding of the effect of composition and microstructural features on overall dynamic behavior. To this end, a systematic approach is adopted to start from single crystal Al and move towards polycrystalline Al, then Al-Cu, and all the way to Al-Cu-Mg-Ag system. Current thesis study constitutes a part of this ongoing work and, therefore, only covers single crystal Al ([001] and [111] directions), polycrystalline Al, and Al-0.1%Cu. Compressive mechanical response of each one of these materials has been investigated in a wide strain rate range that covers quasi-static (from 10-4 to 100 s-1) and dynamic (from 102 to 104 s-1) strain rate regimes. With the exception of single crystal Al (because of limited supplies), additional experiments have been conducted at 120C and 220C within the same strain rate range to understand their thermal softening behavior in varying strain rate regimes. Based on and driven by experimental results, a modified Johnson-Cook model is proposed to describe their rate and temperature dependent constitutive behavior. Finally, in order to investigate susceptibility of these materials and varying microstructures to adiabatic shear localization the two specimen geometries, namely “top hat” and “shear-compression specimen”, have been evaluated. In this evaluation, emphasis is placed upon reliable quantification of strain field within the gage section. Shear compression specimen has been identified to be the best candidate to use in future studies that will explore the tendency of each one of these materials to failure by adiabatic shear banding.
M.S. in Mechanical and Aerospace Engineering, December 2011
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Title: AIRFOIL LONGITUDINAL GUST RESPONSE IN ATTACHED, SEPARATING, AND DETACHED SURGING FLOW
Creator: Weirich, Jeremy Michael
Date: 2013, 2013-12
Description: Longitudinally gusting ow over a nominally two dimensional airfoil is exam- ined over a range of incidence angles and reduced frequencies. The...
Show moreLongitudinally gusting ow over a nominally two dimensional airfoil is exam- ined over a range of incidence angles and reduced frequencies. The response of the airfoil to these gusting ows is compared with classical theory, and is found to follow theory moderately well at low incidence angles across all reduced frequencies. At high incidence angles, the predictive power of the classical model is found to decrease signi cantly. The aerodynamic forces are also decomposed into circulatory and non- circulatory e ects and their relative strength is examined. The circulatory e ects are found to be minimal and constant at low incidence angles, while high incidence angles show strong variation, indication that the wake structure experiences signi - cant changes. The noncirculatory e ects are found to depend linearly on the reduced frequency and a ect the ow more strongly at lower incidence angles. An argument is made for the utility of dividing analysis of the ow into attached ow, separating ow, and fully detached ow regimes. The division is clear when examining how the normalized force coe cients change with reduced frequency, and provides a useful tool for predicting the transition of the ow between regimes.
M.S. in Aerospace Engineering, December 2013
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Title: COMPARING LAGRANGIAN COHERENT STRUCTURES FROM ASSIMILATING OCEAN MODELS TO OCEAN COLOR IMAGES
Creator: Riley, Jordan
Date: 2012-01-04, 2012-12
Description: Lagrangian coherent structures (LCS) have been used to study transport on the ocean surface. The material barrier and separatrix properties of...
Show moreLagrangian coherent structures (LCS) have been used to study transport on the ocean surface. The material barrier and separatrix properties of LCS provide means to compare data-assimilative ocean models. LCS obtained from these models are compared to ocean color images and satellite derived products such as chlorophyll concentration and sea surface temperature from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard the Terra and Aqua satellites. The ability of the LCS to match the satellite images provides insight into the accuracy of the ocean models in capturing predominant ow structures. Two of the ocean model systems use the U.S. Navy Coastal Ocean Model (NCOM), and two model systems use the HYbrid Coordinate Ocean Model (HYCOM). Speci cally, the model systems are the Intra American Seas Nowcast/Forecast System (IASNFS), the NCOM American Seas, the HYCOM + NCODA Global 1/12 , and the HYCOM + NCODA Gulf of Mexico 1/25 .
M.S. in Mechanical and Aerospace Engineering, December 2012
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Title: FLOW IN PARTIALLY CONSTRICTED PLANAR CHANNELS - ORIGINS OF VORTEX SHEDDING AND GLOBAL STABILITY OF NAVIER{STOKES SOLUTIONS
Creator: Boghosian, Michael Edward
Date: 2011-04-17, 2011-05
Description: Vortex shedding is a well-known unsteady uid-dynamic phenomenon occur- ring in a variety of ows in nature including stenosed blood vessels. We...
Show moreVortex shedding is a well-known unsteady uid-dynamic phenomenon occur- ring in a variety of ows in nature including stenosed blood vessels. We nd that current hypotheses regarding the origin of vortex shedding do not apply for the inter- nal ow in a partially constricted two-dimensional channel. As a result, we postulate a novel mechanism to explain the origin of vortex splitting and shedding in this ge- ometry. Numerical simulations of the unsteady, two-dimensional, incompressible Navier{ Stokes equations are performed in a channel having a constriction modeled by a two- parameter Gaussian distribution on both channel walls. Reynolds numbers from 1 to 3000 based on inlet half-channel height and mean inlet velocity and constriction ratios of 0:25, 0:5 and 0:75 are considered. The Navier{Stokes solutions are observed to experience a number of bifurca- tions including unsteady behaviour with shear-layer uctuations and vortex shedding downstream of the constriction. A sequence of events is presented describing how a sustained shear layer instability leads to the unsteady vortex shedding phenomenon via a convective instability and a proposed streamwise pressure-gradient mechanism. In addition, a global linear stability analysis is performed on several station- ary Navier{Stokes solutions to determine the long-term temporal behavior of small amplitude perturbations. Finally, the implications of this research on the hemodynamics in the cephalic vein and potential failure of the brachiocephalic stula are addressed.
Ph.D. in Mechanical Engineering, May 2011
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Title: Investigation of pitot's tubes as a watermeter
Creator: Yoshida, H. T.
Date: 2009, 1912
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/investigationofp00yosh
Thesis (B.S.)--Armour Institute of Technology

Title: An investigation of the flow of liquid fuel through orifices
Creator: Marks, Milton, Clausen, Harold F., Wong, Yak M
Date: 2009, 1920
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/investigationoff00mark
Thesis (B.S.)--Armour Institute of Technology

Title: Investigation of the flow of air in pipes
Creator: Canman, E.l., Kimball, N.f.
Date: 2009, 1912
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/investigationoff00canm
Thesis (B.S.)--Armour Institute of Technology

Title: Investigation of the physical characteristics of various kinds of wire
Creator: Clucas, G. W, Paradise, L. A
Date: 2009, 1906
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/investigationofp00cluc
Thesis (B.S.)--Armour Institute of Technology, 1906 Bibliographical references (leaves....
Show morehttp://www.archive.org/details/investigationofp00cluc
Thesis (B.S.)--Armour Institute of Technology, 1906 Bibliographical references (leaves. 15-16) and index B.S. in Mechanical Engineering, 1906
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Title: MEASUREMENT MODEL OF IONOSPHERIC ELECTRON CONTENT WITH CYGNSS
Creator: Zhang, Jordi Xing
Date: 2013, 2013-12
Description: Global ionospheric imaging is currently limited by a lack of significant quantities of observations over the oceans. This deficiency of...
Show moreGlobal ionospheric imaging is currently limited by a lack of significant quantities of observations over the oceans. This deficiency of measurements arises because coverage from Global Navigation Satellite System (GNSS) remote sensing tools is typically limited to regions over land by using ground-based receivers. This dissertation presents the opportunity to estimate ionospheric data over the oceans by using reflected GNSS signals received by the upcoming Low-Earth Orbit (LEO) satellite constellation Cyclone Global Navigation Satellite System (CYGNSS). CYGNSS is currently being developed by NASA primarily for hurricane predictions. Its eight micro-satellites will have a single-frequency Global Positioning System (GPS) receiver onboard and zenith and nadir antennas that collect GPS signals reflecting from the ocean surface of Earth. This study investigates the possibility of leveraging CYGNSS for a secondary science mission, using GNSS-Reflectometry for ionospheric remote sensing. A mathematical model is developed that retrieves ionospheric electron content by using ranging measurements from direct and ocean-reflected GPS signals onboard CYGNSS satellites. The measurement model terms can be grouped as geometric raypath and signal refraction components due to the troposphere and the ionosphere. Each term of the model is analyzed and quantified by applying fundamental physical principles and empirical models. The implementation of a multi-orbit simulation estimates the magnitudes of anticipated electron content measurements with CYGNSS.
M.S. in Mechanical and Aerospace Engineering, December 2013
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Title: MECHANICAL PROPERTIES AND MICROSTRUCTURE OF HEAT AFFECTED ZONE IN HPS 100W STEEL
Creator: Lu, Junhua
Date: 2011-11-21, 2011-12
Description: In the present investigation, thermal simulated specimens were used to investigate the effect of peak temperature during welding on...
Show moreIn the present investigation, thermal simulated specimens were used to investigate the effect of peak temperature during welding on characteristic fracture toughness and microstructural features of the heat-affected zones (HAZ) of HPS 100W Steel. HPS 100W is a new grade of bridge steel included in ASTM A709 Standard. The material was subjected to varying thermal profiles to simulate the different subzones of HAZ and the resultant microstructures were observed and mechanical properties determined. HAZ simulation was carried out in a Gleeble 3500 at different peak temperatures of 850oC, 1100oC and 1300oC with heat inputs of 3kJ/mm along with specimens transverse or longitudinal to the rolling direction. Subsequently, impact toughness data were obtained at different temperatures by means of a Charpy test. Finally, the different microstructures were characterized using optical microscopy, SEM and TEM in order to correlate the structure-property relationship of the HAZ for HPS 100W steel. Due to small heat-input and accelerated cooling, the grain size in HAZ is relatively small and the structures are ductile. The Charpy impact results show the transverse rolling direction toughness for lower peak temperature and base material have lower values than that of longitudinal direction samples. Nevertheless even the lowest Charpy values obtained are well above minimum values required for structural application transportation. The HAZ showed higher absorbed impact energy in lower temperature. Also, precipitation dissolution study of NbC and Cu was carried out in the end. Cu element is the strengthening element. The NbC have grain refining effect at elevated temperature.
M.S. in Science and Engineering, December 2011
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Title: Materials used in concrete construction
Creator: Houghton, V. A.
Date: 2009, 1906
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/materialsusedinc00houg
Thesis (B.S.)--Armour Institute of Technology;Includes bibliographical references leaves...
Show morehttp://www.archive.org/details/materialsusedinc00houg
Thesis (B.S.)--Armour Institute of Technology;Includes bibliographical references leaves 53-54 and index
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