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Computational Investigation Of Ethanol And Bifuel Feasibility In Solstice Engine, Adam Michael Blake Jan 2012

Computational Investigation Of Ethanol And Bifuel Feasibility In Solstice Engine, Adam Michael Blake

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A Gasoline Direct Injection (GDI) engine enables an increased fuel efficiency and higher power output than a conventional Port Fuel Injection (PFI) system. By injecting pressurized fuel straight into each cylinder of an internal-combustion engine, the degree of fuel atomization is increased, as well as the fuel vaporization rate. In order to further harness the effects of direct injection, ethanol is implemented as a fuel. The cooling effect of ethanol fuel droplets changing to vapor inside the combustion chamber facilitates a higher compression ratio, thus increasing engine power and efficiency. Three dimensional computational simulation is used to investigate the feasibility …


Measurement Of Static And Dynamic Performance Characteristics Of Electric Propulsion Systems, Aron Jon Brezina Jan 2012

Measurement Of Static And Dynamic Performance Characteristics Of Electric Propulsion Systems, Aron Jon Brezina

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Today's unmanned aerial vehicles are being utilized by numerous groups around the world for various missions. Most of the smaller vehicles that have been developed use commercially-off-the-shelf parts, and little information about the performance characteristics of the propulsion systems is available in the archival literature. In light of this, the aim of the present research was to determine the performance of various small-scale propellers in the 4.0 to 6.0 inch diameter range driven by an electric motor. An experimental test stand was designed and constructed in which the propeller/electric motor was mounted in a wind tunnel for both static and …


Characterization, Stability, And Transport Through Defects In Graphene Nanoribbons, Sri Krishna Divya Pemmaraju Jan 2012

Characterization, Stability, And Transport Through Defects In Graphene Nanoribbons, Sri Krishna Divya Pemmaraju

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Graphene nanoribbons (GNRs) constitute a new class of nanostructured materials with unique properties and significant potential for applications. During production of GNRs, defects are generally introduced within the lattice. Assessment of defects' stability and characterization of their effects on GNRs are therefore very important for predicting GNRs performance under realistic circumstances. Here we consider various possible defects, namely the ones caused by removal/addition of carbon atoms from/to the lattice as well as those caused by bond rotation/rearrangement. Our study is based on ab initio geometry optimization and electronic structure calculations. We determine which defects can be stable in graphene nanoflakes …


Modeling And Simulation Of A Dynamic Turbofan Engine Using Matlab/Simulink, Scott Michael Eastbourn Jan 2012

Modeling And Simulation Of A Dynamic Turbofan Engine Using Matlab/Simulink, Scott Michael Eastbourn

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A dynamic, high-bypass turbofan engine has been developed in the modeling and simulation environment of MATLAB/Simulink. Individual elements, including the fan, high pressure compressor, combustor, high pressure turbine, low pressure turbine, plenum volumes, and exit nozzle, have been combined to investigate the behavior of a typical turbofan engine throughout an aircraft mission. Special attention has been paid to the development of transient capabilities throughout the model, increasing model fidelity, eliminating algebraic constraints, and reducing simulation time through the use of advanced numerical solvers. This lessening of computation times is paramount for conducting future aircraft system-level design trade studies efficiently, as …


Effect Of Cooling Rate And Mold Counter Pressure On The Crystallinity And Foaming Control In Microcellular Injection Molded Polypropylene Parts, Jeffrey Scott Cousineau Jan 2012

Effect Of Cooling Rate And Mold Counter Pressure On The Crystallinity And Foaming Control In Microcellular Injection Molded Polypropylene Parts, Jeffrey Scott Cousineau

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Microcellular polymer injection molding is a growing industry technique due to its ability to produce dimensionally stable stress free parts while reducing cycle time, material usage, and energy costs. The process was invented by Dr. Nam P. Suh at the Massachusetts Institute of Technology in the early 1980's. The basic idea is to dissolve a supercritical fluid into the polymer melt which will nucleate and expand within the part core after injection during the cooling stage. Microcellular polymer injection molding is becoming increasingly popular in automotive, semiconductor, and industrial applications. While the technique has been widely successful using amorphous polymers, …


Computational Investigation Of A Hinge-Connected Hovering Plate, Zachary Robert Gaston Jan 2012

Computational Investigation Of A Hinge-Connected Hovering Plate, Zachary Robert Gaston

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A simplified conceptual flapping wing MAV design, capable of hover, is formed from the works of both biologists and engineers, studying the behavior of flying insects and the aerodynamics of flapping flight. With this new model, hovering hinged plates are used to study the effects of passive deflection on aerodynamic performance using two-dimensional Direct Numerical Simulations (DNS) at low Reynolds numbers (Re). The hinge is modeled as a torsional spring at the leading edge, where prescribed motion is applied. The influence of forced-to-natural frequency ratio (hinge stiffness) and stroke-to-chord ratio (leading edge kinematics) are studied, to explore the effects that …


Application Of Auto-Tracking To The Study Of Insect Body Kinematics In Maneuver Flight, Shreyas Vathul Subramanian Jan 2012

Application Of Auto-Tracking To The Study Of Insect Body Kinematics In Maneuver Flight, Shreyas Vathul Subramanian

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There is a need to explain the complex phenomena that underlies the seemingly effortless flight modes of the dragonfly (Infra -order Anisoptera). However, measuring the body kinematics during flight is labor intensive. Thus a robust system was developed that automatically tracks and quantifies the body kinematics of a dragonfly during voluntary and escape take-offs, as well as maneuvers. Ultimately, the tool, which was developed using a custom code in C++ using the open source library OpenCV (Open Computer Vision), would be used to analyze bulk samples of high speed videos providing raw images at the rate of approximately 1000 frames …


Computational Study On Micro-Pilot Flame Ignition Strategy For A Direct Injection Stratified Charge Rotary Engine, Zachary Steven Votaw Jan 2012

Computational Study On Micro-Pilot Flame Ignition Strategy For A Direct Injection Stratified Charge Rotary Engine, Zachary Steven Votaw

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The Office of Security of Defense's Assured Fuels Initiative has recently been pressing for a single fuel battle space. This endeavor requires modifying many of the vehicle power plants currently in operation throughout the Armed Forces. The RQ-7 Shadow, an unmanned aerial vehicle (UAV) utilized by the Marine Corp and Army for reconnaissance purposes, is powered by UEL's AR741 rotary engine and functions on aviation fuel. One effort underway has been focused on developing this rotary engine system to operate on heavy fuels using direct injection technology and charge stratification. Although the rotary engine has many advantages over standard reciprocating …