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$THE CHARACTERIZATION FOR B2 STRUCTURE AND L2\ STRUCTURE IN THE AG-MG AND AG-MG-IN SYSTEM$

Title: THE CHARACTERIZATION FOR B2 STRUCTURE AND L2\ STRUCTURE IN THE AG-MG AND AG-MG-IN SYSTEM
Creator: Kim, Do Hyung
Date: 2013, 2013-05
Description: The concentration of point defects and the long range order for ordered B2 AgMg alloys, quenched from 973K, was investigated by statistical...
Show moreThe concentration of point defects and the long range order for ordered B2 AgMg alloys, quenched from 973K, was investigated by statistical thermodynamic modeling, powder X-Ray Diffractometery and diffraction simulation as a function of composition. The lattice parameter behavior on the Ag rich side are expectably having constitutional and thermal anti-site defects on both Ag and Mg sub-lattices, corresponding to the literature data. On the other hand, the Mg rich side has substantially thermal vacancy defects based on the lattice parameter data which shows lower, compared with previously reported data. Concentration of the equilibrium point defects at 973K was calculated from two thermodynamic models, where the Ag rich side was based on the constitutional and thermal anti-site defect formation and the Mg rich side was based on the hybrid defect formation consisting of vacancy, Mg and Ag anti-site defects The experimental long range order at 973K, determined from the integrated intensity ratio of (100) super-lattice reflection to (200) fundamental reflection, is in quite good agreement with the theoretical long range order at 973K based on the calculated integral intensities from the diffraction simulation with the equilibrium concentration of each point defect, obtained by two thermodynamic models. Furthermore, point defect hardening coefficients on both sides of stoichiometry were determined by the measurement of the Vickers hardness as a function of the equilibrium concentration of the main point defects deduced from two thermodynamic models. The hardening coefficient is G/16 for the Ag rich side with respect to Ag anti-site defects and G/3.1 for the Mg rich side with respect to vacancy defects. Also, two hardening coefficients are corresponding to the empirical correlation for the several binary B2 intermetallic compounds with anti-site defects (G/9 to G/85) xvi and vacancy defects (G/3 to G/4). This suggests that the elastic size effect on the Ag rich side is the primary hardening mechanism due to constitutional and thermal Ag anti-site defects while the Mg rich side is likely to have the elastic modulus effect due to constitutional and thermal vacancy defects. It is also indicated that the vacancy defect is more significant hardener than Ag anti-site defects for the ordered B2 AgMg intermetallic system. The partial liquidus projection in the Ag-Mg-In ternary system was established by the primary phase and liquidus temperature, using the Scanning Electron Microscopy, Energy Dispersive Spectroscopy and Differential Scanning Calorimetry. The results showed that the AgMg1-xInx phase of the Ag-Mg-In ternary system has a large primary solidification field up to 90 at.% of In, so that most ternary invariant reactions of the In rich field must be formed beyond 90 at.% of In. The liquid-solid schematic reactions in the Ag rich field were experimentally confirmed, but those of the In rich side have not been established. Furthermore, the ordering phase transition and melting temperature of the Heusler phase AgMg1-xInx alloys were investigated using Differential Scanning Calorimetry, Scanning Electron Microscopy, and powder X-Ray Diffractometery. The DSC results indicated that the melting temperature decreased with increasing the In composition, but a thermal peak for the ordering phase transition was not detected due to either a very small heat of transition or a second order transformation. The XRD results showed that the L21 structure of the Heusler phase was observed for the 15 at.% of In alloy and the degree of order of L21 structure continuously increased with the In composition, resulting from the (111) super-lattice intensity with respect to the In composition. The L21 structure ordering of the 15 at.% of In and 20 at.% of In system xvii was gradually decreased with increasing the annealing temperature, corresponding to decreasing the (111) super-lattice intensity and the long rang order parameters of the L21 structure. These XRD behaviors suggest that the L21/B2 ordering transformation phenomena is a second order transformation with respect to temperature.
PH.D in Material Science and Engineering, May 2013
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Title: The performance of a Harrington forced draft chain grate stoker
Creator: Barce, Stanley H, Doolittle, Charles B, Wolgemuth, Bruno E., Quinlan, Frank D.
Date: 2009, 1921
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/performanceofhar00barc
Thesis (B.S.)--Armour Institute of Technology

Title: HYBRID ELECTROSTATIC AND MICRO-STRUCTURED ADHESIVES FOR ROBOTIC APPLICATIONS
Creator: Ruffatto, Donald F., Iii
Date: 2015, 2015-07
Description: Current adhesives and gripping mechanisms used in many robotics applica- tions function on very speci c surface types or at de ned attachment...
Show moreCurrent adhesives and gripping mechanisms used in many robotics applica- tions function on very speci c surface types or at de ned attachment locations. A controllable, i.e. ON-OFF, adhesive mechanism that can operate on a wide range of surfaces would be very advantageous. Such a device would have applications ranging from robotic gripping and climbing to satellite docking and inspection/service mis- sions. The main goal of the research presented here was to create such an attachment mechanism through the use of a new hybrid adhesive technology. The newly devel- oped adhesive technology is a hybridization of electrostatic and micro-structured dry adhesion. The result provides enhanced robustness and utility, particularly on rough surfaces. There were challenges not only in the integration of these two adhesive elements but also with its application in a complete gripping mechanism. Electrostatic and directional dry adhesives were both individually investigated. The electrode geometry for an electrostatic adhesive was optimized for maximum ad- hesion force using nite element analysis software. Optimization results were then veri ed through experimental testing. New manufacturing techniques were also de- veloped for electrostatic adhesives that utilized a metalized mesh embedded in a sili- cone polymer and Kapton lm based construction, greatly improving adhesion. The micro-structured dry adhesive used was provided by Dr. Parness, from the NASA Jet Propulsion Lab (JPL), and consists of an array of vertical stalks with an angled front face, referred to as micro-wedges. The hybrid electrostatic dry adhesive (EDA) was created by fabricating the electrostatic adhesive directly on top of a dry adhesive mold. This process created an array of dry adhesive micro-wedges directly on the surface of the electrostatic adhesive. In operation the electrostatic adhesive provides a normal force which serves to pull the dry adhesive into the surface substrate. With greater surface contact more of the dry adhesive is able to engage, bring the electro-static adhesive even closer to the surface and increasing its e ectiveness. Therefore, the combination of these two technologies creates a positive feedback cycle whose whole is often greater than the sum of its parts. An interface mechanism is needed to transmit applied loads from a rigid struc- ture to the exiable adhesive while still maintaining its conformability. This is es- pecially important for strong adhesion on rough surfaces, such as tile and drywall. Di erent concepts such as a structured brillar hierarchy and a uid- lled backing pouch have been explored. Additionally, nite element analysis was used to evaluate di erent fribrillar shapes and geometry for the structured hierarchy. The goal was to equalize the load distribution across the adhesive while still maintaining surface compliance. A gripper mechanism was also created which used a servo for actuation and three rigid tiles with a directional dry adhesive. It was tested on a perching Micro Air Vehicle (MAV) as well as in the RoboDome facility at NASA's Jet Propulsion lab to simulate a satellite docking/capture maneuver.
Ph.D. in Mechanical and Aerospace Engineering, July 2015
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Title: IDENTIFY AND IMPROVE OBSTACLE AVOIDANCE CAPABILITY OF UNMANNED GROUND VEHICLE
Creator: Nie, Chenghui
Date: 2015, 2015-05
Description: An Unmanned Ground Vehicle (UGV), incorporating a high level of obstacle avoidance capability, benefits from field operations. Such a UGV...
Show moreAn Unmanned Ground Vehicle (UGV), incorporating a high level of obstacle avoidance capability, benefits from field operations. Such a UGV would be better able to travel at a high average speed to quickly finish tasks, as well as quickly alter its trajectory to avoid getting into hostile situation. However, avoiding obstacles at high speed is challenging, since the danger of collisions with obstacle is increased with vehicle speed. This thesis developed novel metrics to mathematically identify the obstacle avoidance capability of ground vehicles. The theory is applied to demonstrate the characteristics of the obstacle avoidance capability of generalized rigid bodies and three types of wheeled ground vehicles: Ackermann steered, differential steered and omni-directional vehicle. The design guidelines are provided in the final chapters to improve obstacle avoidance capabilities of these three types of wheeled ground vehicles. I demonstrated in this thesis that the Ackermann steered vehicle's obstacle avoidance capability is related to the location of its center of mass. I utilized the obstacle avoidance theory to create a novel Variable Inertial Vehicle (VIV), an unmanned ground vehicle with a capability to control the location of its center of mass during locotion. Experimental results are presented to demonstrate the improved obstacle avoidance capability at the end. This thesis also experimental evaluates the characteristics of the obstacle avoidance capability of an omni-directional unmanned ground vehicle. This omnidirectional vehicle is comprised of four independent differential steered units, Active Split Offset Caster (ASOC). Both the characteristics of the vehicle system and ASOC kinematics are demonstrated. Experimental results are presented at the end to validate its distinct obstacle avoidance capability in challenging outdoor terrains.
Ph.D. in Mechanical and Aerospace Engineering, May 2015
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Title: The physical properties and tests of lubricating oils
Creator: Robechek, B., Steindler, N. A.
Date: 2009, 1917
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/physicalproperti00robe
Thesis (B.S.)--Armour Institute of Technology; Bibliography: leaf 33

Title: INVESTIGATION AND MODELING OF PRESSURE DEPENDENT YIELD BEHAVIOR OF 3D STOCHASTIC AND PERIODIC FOAMS
Creator: Ayyagari Venkata S, Ravi Sastri
Date: 2013, 2013-07
Description: With growing potential of cellular solids in a multitude of diverse engineering applications including but not limited to automotive,...
Show moreWith growing potential of cellular solids in a multitude of diverse engineering applications including but not limited to automotive, aerospace, naval and biomed- ical industries as lightweight alternatives and space lling cores in sandwich struc- tures, need for predictive yield/failure criteria for these load bearing members under multiaxial stress states becomes critical. Although there exist several yield criteria proposed in the literature for highly porous solid foams, they are all phenomenolog- ical in nature, rely on relatively long list of model parameters that require di cult experimentation not readily available to end user, and none of them can handle the anisotropy observed in the majority of commercially available solid foams. Further, it is by now well established that, unlike commonly used engineering bulk solids, the yield behavior of highly porous solid foams is signi cantly in uenced by the hydro- static component of stress. In majority of phenomenological yield criteria proposed for solid foams this dependence is expressed by a quadratic pressure term. The scope of this study is quite comprehensive in the sense that it integrates analytical and computational investigation of yield behavior in solid foams along with extensive validation by recent experimental results produced in our lab. Present study proposes a physics based approach by hypothesizing that the yielding of stochastic foams is governed by the total elastic strain energy density, which leads to an energy based yield criterion for transversely isotropic foams and also provides a physical basis for the quadratic pressure dependence commonly adopted in existing phenomenolog- ical models. An added bene t of the analytical framework proposed in this work is that it introduces new scalar measures of stress and strain, which are referred to as characteristic stress and characteristic strain, that function in an analogous way to e ective (von Mises) stress and strain commonly used in analyzing the yield and post- yield behavior of bulk metals. Besides accommodating anisotropy, this energy-based xii yield criterion renders a unique advantage by relying only on the elastic properties and uniaxial yield strengths of the material, which makes the proposed yield criterion extremely practical for end user. Results from experimental data obtained from multiaxial testing of Divinycell H100 and H130 foams (Sha q, 2009; Ehaab, 2011) as well as a series of extensive com- putational simulations performed in this study on: a) periodic Kelvin foam models (both isotropic and transversely isotropic) of varying relative densities, b) stochastic Voronoi foams (both isotropic and transversely isotropic), point out to an additional linear pressure dependence in the yield behavior of solid foams, from a load-sharing viewpoint. This dependence is observed to be more pronounced at lower relative den- sities. A simple quantitative technique which is based on the partition of elastic strain energy into bending and stretch components is used to identify the distribution of deformation modes at microstructural level, along with its in uence on load sharing as a function of stress path. Furthermore, a plasticity model that incorporates a ow rule and hardening law are presented which allows the analysis of inelastic deforma- tions in solid foams in a continuum framework. Such models facilitate development of user de ned material model (UMAT) that allow evaluating the performance of proposed yield criterion under complex loading scenarios, such as indentation and punch loading.
PH.D in Mechanical and Aerospace Engineering, July 2013
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Title: EFFECTS OF FUEL PROPERTIES ON THE COMBUSTION PROCESS OF AN ADVANCED DIESEL ENGINE
Creator: Ramos Silva, Cedric Zacarias
Date: 2015, 2015-12
Description: Internal combustion engines are encountered in our everyday lives in passenger cars and heavy-duty vehicles such as trucks and buses. While...
Show moreInternal combustion engines are encountered in our everyday lives in passenger cars and heavy-duty vehicles such as trucks and buses. While conventional compression ignition engines burn diesel fuel with an oxidizer (generally air) in a combustion chamber, much recent research has focused on improving the efficiency of combustion and reducing vehicle pollutant output through the usage of fuels with properties which differ from those of diesel fuel. In particular, this study focuses on a dual fuel engine in which two fuels (usually gasoline or diesel fuel mixed with an alternate fuel) are separately injected and combusted. Results from an Argonne National Laboratory test cell utilizing a 13 Liter (L) heavy duty dual fuel engine running in a combustion mode known as Reactivity Controlled Compression Ignition (RCCI) were leveraged in this work. In a RCCI engine, two fuels of different reactivities (low reactivity and high reactivity) are used in order to control in-cylinder fuel reactivity and allow for the optimization of combustion phasing and duration. In addition, RCCI combustion has been shown to produce low amounts of nitrogen oxides (NOx) as well as particulate matter (PM) emissions which may eliminate the need for expensive after-treatment systems. The combustion shaping capabilities and low emissions of RCCI dual fuel engines enable reductions in heat transfer losses and as such the increase of fuel efficiency. In order to understand the dynamics of such engines, a detailed simulation model of a RCCI dual fuel engine was constructed and developed using the Gamma Technologies (GT) simulation suite in particular GT-POWER and GT-SUITE. Modeling of the complex gas exchange process as well as the combustion process of the 13L RCCI dual fuel engine were both undertaken. This model was then leveraged to examine the effect of fuel properties on the combustion process using GT simulation suite. Experimental data from the 13L engine at Argonne was used to validate the models of the gas exchange and combustion processes. For the gas exchange process as well as the combustion process, the results from the simulation model fairly accurately match the experimental data from the Argonne engine. To achieve RCCI, the engine is equipped with a complex air handling system which includes two turbochargers as well as exhaust gas recirculation (EGR). To ensure that the gas exchange process was accurately captured, the experimental intake pressure, EGR fraction (EGR mass flow rate divided by the sum of EGR mass flow rate and air mass flow), fresh airflow rate, maximum in-cylinder pressure, IMEP and exhaust pressure were compared with the simulation results given by GT-POWER and GT-POST. By modeling the engine components in GT-POWER and adding additional control algorithms, the previously mentioned parameters predictions were within 10% of the engine data. The combustion process was modeled using a Direct-Injection Jet (DI-Jet) combustion model. The DI-Jet model is a predictive combustion model which predicts the burn rate, combustion rate and NOx emissions. This model was calibrated by comparing the experimental and simulation heat release curves. Particular attention is given to accurately capturing the start of combustion and ignition delay period because they affect the combustion process the most.
M.S. in Mechanical and Aerospace Engineering, December 2015
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Title: Design, installation and operation of cams for the valve-gear of a three-cylinder, 8 x 10 in. Westinghouse gas engine
Creator: Paterson, William, Bunge, Ludwig W. A
Date: 2009, 1915
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/designinstallati00pate
Thesis (B.S.)--Armour Institute of Technology, 1915 B.S. in Mechanical Engineering, 1915

Title: Design and installation of power plant and heating system for the zone of camp activities and amusements, Camp Funston, Kansas
Creator: Pimstein, Sidney.
Date: 2009, 1919
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/designinstallati00pims
Thesis (B.S.)--Armour Institute of Technology; Includes folded leaves in back pocket

Title: Design of an exhaust gas calorimeter for automobile engines
Creator: Mayer, J. Leo., Hibbard, Lewis E
Date: 2009, 1915
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/designofexhaustg00maye
Thesis (B.S.)--Armour Institute of Technology, 1915 B.S. in Mechanical Engineering, 1915

Title: The design of a tractor for general farm and road work
Creator: Evans, R. T.
Date: 2009, 1917
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/designoftractorf00evan
Thesis (B.S.)--Armour Institute of Technology; Includes folded leaves in back pocket

Title: Economy tests of 40 H. P. automobile engine including construction and operation of manograph
Creator: Lawrence, M. F, Dunn, W. C.
Date: 2009, 1912
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/economytestsof4000lawr
Thesis (B.S.)--Armour Institute of Technology, 1912 B.S. in Mechanical Engineering, 1912

Title: Economical banking of fires with a green chain grate storker
Creator: Hayes, J. J., Jr, Jarvis, B. H.
Date: 2009, 1913
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/economicalbankin00haye
Thesis (B.S.)--Armour Institute of Technology

Title: Economy and capacity test of a three ton York ice plant
Creator: Sir, Walter Waldemar., Bohn, Robert, Cooley, Gilbert
Date: 2009, 1914
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/economycapacityt00sirw
Thesis (B.S.)--Armour Institute of Technology, 1914 Includes bibliographical references ...
Show morehttp://www.archive.org/details/economycapacityt00sirw
Thesis (B.S.)--Armour Institute of Technology, 1914 Includes bibliographical references (leaf 26) and index B.S. in Mechanical Engineering, 1914
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Title: An economy analysis of automobile engines by a new method
Creator: White, H. S., Fritze, G. M., King, L. A.
Date: 2009, 1917
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/economyanalysiso00whit
Thesis (B.S.)--Armour Institute of Technology; Includes folded leaves in back pocket

Title: Efficiency test of a hydro-electric plant
Date: 2009, 1910
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/effeciencytestof00baug
Thesis (B.S.)--Armour Institute of Technology, 1910 B.S. in Mechanical Engineering, 1910

Title: The effect in economy of an automobile engine of varying the igniter and fuel valve opening
Creator: Dekker, Harry G., Mayes, Frank H.
Date: 2009, 1909
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/effectineconomyo00dekk
Thesis (B.S.)--Armour Institute of Technology; Includes bibliographical references and index

Title: Experiments with Westinghouse gas engine
Creator: Dreffein, C. G., Turnbull, I. J
Date: 2009, 1907
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/experimentswithw00dref
Thesis (B.S.)--Armour Institute of Technology, 1907 B.S. in Mechanical Engineering, 1907

Title: Experimental investigation of the flow of steam thru pipes by means of the pitot tube
Creator: Friedlander, L. G., Busse, C. F.
Date: 2009, 1908
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/experimentalinve00frie
Thesis (B.S.)--Armour Institute of Technology

Title: Experimental development of a special indicator for the gas engine
Creator: Brubaker, W. C.
Date: 2009, 1906
Publisher: Armour Institute of Technology
Description: http://www.archive.org/details/experimentaldeve00brub
Thesis (B.S.)--Armour Institute of Technology

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