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Articles 1441 - 1470 of 3180

Full-Text Articles in Engineering

Enhanced Specific Heat Of Molten Salt Nanofluids, Hani Tiznobaik May 2016

Enhanced Specific Heat Of Molten Salt Nanofluids, Hani Tiznobaik

Mechanical and Aerospace Engineering Dissertations - Archive

Concentrated solar power uses general thermodynamic cycles (such as Rankine or Gas turbine cycle) to produce electricity and thus its efficiency primarily relies on the operating temperature of thermal energy storage. Current thermal energy storage medium is organic material such as synthetic oil or fatty acid. However, these materials are not stable at high temperatures due to their thermal decomposition. Using molten salts as thermal energy storage medium is a very attractive option since they are thermally stable at high temperatures (over 600 °C). They also have very lower vapor pressure (for reducing mechanical stress on structure materials), less reactive, …

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Data Engineering In Aerospace Systems Design & Forecasting, Eric Haney May 2016

Data Engineering In Aerospace Systems Design & Forecasting, Eric Haney

Mechanical and Aerospace Engineering Dissertations - Archive

Although engineers spend the majority of their time finding, managing, and transforming data, the process of how to handle data remains under-educated & under-researched. The alignment of engineering education & proficiency along an analysis-dominated mindset is ill-conditioned for the growing reliance on data-driven processes and holistic decision-making requirements. Although a majority of driving decisions in the aerospace industry rely heavily on utilizing existing organizational data-stores and built-in knowledge bases to make informed decisions, formalized development & implementation of data within existing engineering processes is seldom addressed. The current research defines a complementary discipline, Data-Engineering, which seeks to capitalize on the …

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Exergy Analysis Of A Pulse Detonation Engine Linear Power Generator, Raheem Temitope Bello May 2016

Exergy Analysis Of A Pulse Detonation Engine Linear Power Generator, Raheem Temitope Bello

Mechanical and Aerospace Engineering Dissertations - Archive

The fuel efficiency of a power generator is a key metric for evaluating its performance. The common engineering practice is to determine the thermal efficiency of the system by applying the conservation of energy also known as the first law of thermodynamics. However, for heat engine power generators, and other thermal systems, the thermal efficiency is not sufficient for detailed system performance analysis. Exergy analysis, which applies both the first and second law of thermodynamics, enables the determination of the directionality of thermal processes, and the system’s available work. This more complete thermodynamic analysis approach is applied to a pulse …

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Maximizing Use Of Air-Side Economization, Direct And Indirect Evaporative Cooling For Energy Efficient Data Centers, Betsegaw Kebede Gebrehiwot May 2016

Maximizing Use Of Air-Side Economization, Direct And Indirect Evaporative Cooling For Energy Efficient Data Centers, Betsegaw Kebede Gebrehiwot

Mechanical and Aerospace Engineering Dissertations - Archive

Data centers house information technology (IT) equipment such as servers and network switches which are vital for our networked modern society by providing digital data storage, data processing and connectivity. Data centers house few hundreds to tens of thousands of IT equipment that consume few kilowatt-hours to multi-megawatt-hours of electrical energy that gets dissipated as heat. IT equipment need to be properly cooled so that they operate reliably for their expected lifetime. For air cooled IT equipment, manufacturers provide heat sinks, cold plates, fans, et cetera to remove heat from the vicinity of heat dissipating components and data centers need …

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Human Robot Interaction With 3d-Printed Whole Body Robotic Skin, Fahad Mirza May 2016

Human Robot Interaction With 3d-Printed Whole Body Robotic Skin, Fahad Mirza

Mechanical and Aerospace Engineering Theses - Archive

This thesis presents work of a newly developed pressure sensor for robot skin, from fabrication to application. Robot skin similar to human skin meant to have several sensing capabilities including pressure, temperature etc. As the conventional semiconductor manufacturing process is not adequate for multi-modal sensors, a new process, called Electro-Hydro-Dynamic Printing, has been explored in this work. A calibration technique was implemented along with printing parameter fixation by trial and error. A testing methodology was proposed to test these sensors and several commercial robots were used to conduct pHRI experiments with pressure sensing capability.

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Finite Element Based Cross-Sectional Buckling Optimization For A Constant Area, Pinned-Pinned Composite Column, Anirudh Srinivas May 2016

Finite Element Based Cross-Sectional Buckling Optimization For A Constant Area, Pinned-Pinned Composite Column, Anirudh Srinivas

Mechanical and Aerospace Engineering Theses - Archive

In archery, dynamic buckling compromises the target accuracy of arrows. For both dynamic and quasi-static buckling, the buckling load depends on the cross-sectional area moment of inertia, which can be increased by modifying the cross-sectional shape of the arrow shaft. Arrows commercially available today are made up of composite materials and have a tubular circular cross-section. In this study an effort has been made to optimize the cross-sectional shape of the composite arrow shaft, using finite element based, quasi-static buckling analysis keeping the length and area of the cross-section constant. The composite column is pinned at both ends and is …

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Capacity Fade Of Valve Regulated Lead Acid & Lithium Iron Phosphate Batteries Through High Rate, Pulsed Loads, Christopher Lee Williams May 2016

Capacity Fade Of Valve Regulated Lead Acid & Lithium Iron Phosphate Batteries Through High Rate, Pulsed Loads, Christopher Lee Williams

Industrial, Manufacturing, and Systems Theses - Archive

Electrochemical energy storage has become more power and energy dense in recent years. Many applications demanding energy storage operate in a pulsed manner. The most common chemistries considered for use in these applications include valve regulated lead acid (VRLA) and lithium-ion (LI). In the work presented here, one of each of these types of batteries has been assembled with ~60 V open circuit potentials (OCPs) and is in the process of experimentally characterizing their capacity fade and impedance growth when they are used to drive a high current pulsed load in a 5 seconds on / 5 seconds off pulsed …

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Human Robot Interaction Using Knowledge Base Approach, Utsav Shah May 2016

Human Robot Interaction Using Knowledge Base Approach, Utsav Shah

Mechanical and Aerospace Engineering Theses - Archive

This research investigated Human Robot Interaction modalities. The performance of a robotic prosthetic hand (RPH) was used as a test bed robot. A user wearable glove was fitted with sensors to provide tele-control of the RPH. An open hardware control and easily expandable research platform based on LabVIEW software and myRIO control hardware was developed. LabVIEW graphical programming platform provides the tools for the development to customized interfaces for visualization purposes which is desired in research. The research platform was used to calibrate and control the operation of the artificial hand using various modalities such as open loop, glove master-slave …

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E-Learning Modules For Nuclear Reactor Heat Transfer, Praveen Bharadwaj Jayaram May 2016

E-Learning Modules For Nuclear Reactor Heat Transfer, Praveen Bharadwaj Jayaram

Mechanical and Aerospace Engineering Theses - Archive

E learning in engineering education is becoming popular at several universities as it allows instructors to create content that the students may view and interact with at his/her own convenience. Web-based simulation and what-if analysis are examples of such educational content and has proved to be extremely beneficial for engineering students. Such pedagogical content promote active learning and encourage students to experiment and be more creative. The main objective of this project is to develop web based learning modules, in the form of analytical simulations, for the Reactor Thermal Hydraulics course offered by the College of Engineering at UT Arlington. …

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Experimental And Numerical Study Of Marangoni Convection In A Sandwiched Droplet, Ajinkya Shrikrishna Shetye May 2016

Experimental And Numerical Study Of Marangoni Convection In A Sandwiched Droplet, Ajinkya Shrikrishna Shetye

Mechanical and Aerospace Engineering Theses - Archive

This research studies velocity fields resulted from the marangoni effect in a microscale droplet sandwiched in parallel plates. Surface tension becomes the dominant driving force as opposed to body forces as we move from the macroscale to microscale. Surface tension gradient is required to generate marangoni convection. This could be produced by a temperature gradient along the meniscus of the drop. To study this interfacial phenomenon, indium tin oxide micro thin film heater is utilized to create the necessary temperature gradient. Pure marangoni effect is studied by suppressing the evaporation effect on fluid flow by using an ionic liquid (molten …

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Computational Analysis Of Blast Induced Damage On Neurons In Brain During Traumatic Brain Injury, Divya Swamy Bandaru May 2016

Computational Analysis Of Blast Induced Damage On Neurons In Brain During Traumatic Brain Injury, Divya Swamy Bandaru

Mechanical and Aerospace Engineering Theses - Archive

Concussions are the most common kind of brain injuries, they are also called as mild Traumatic Brain Injuries (mTBI). In recent times, mTBIs are perceived as one of the major health problems faced by millions across the world. TBIs occur when there is a sudden acceleration or deceleration force is applied on the human brain that is encapsulated in the skull. When blasts caused by typical IEDs (induced by explosives) in wars propagate through the head, cavitation bubbles are formed in the brain tissue. When these bubbles collapse, they form cavitation-induced shock wave. It has been found that the strains …

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Image Processing Of Triple Shock Wave Evolution, Katherine Yarbrough May 2016

Image Processing Of Triple Shock Wave Evolution, Katherine Yarbrough

Mechanical and Aerospace Engineering Theses - Archive

Shock diamonds occur in over- or under- expanded supersonic flow. They occur in the unsteady jet of a pulse detonation engine, displaying an array of complex features. Due to the highly transient nature of the flow, it must be captured using high-speed cinematography. A study of image processing of shock reflection in unsteady flow is presented. Using a computer-based environment, a method was developed to process images of shock waves to pinpoint where the shock wave starts. Using mathematical methods, such as Abel transforms, a computer code, written in Matlab, was developed to accurately transform the images to detect density …

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Experimental Characterization Of Hybrid Cooled Cisco Servers Including The Effect Of Warm Water Cooling, Md Malekkul Islam May 2016

Experimental Characterization Of Hybrid Cooled Cisco Servers Including The Effect Of Warm Water Cooling, Md Malekkul Islam

Mechanical and Aerospace Engineering Theses - Archive

The information technology (IT) owners are experiencing a greater cooling challenge because of the increase in power density due to modern computational needs. The non-uniform power density in each server is forcing the industry to use hybrid cooling technology. Server components of different cooling requirement needs air water hybrid cooling which offers variable design alternatives. Such hybrid cooling technology cools the high heat generating components by using water or water based fluid, whereas, the rest of the components are cooled by air using internal fans. Conventional air cooling is more than sufficient for the components with less thermal demand. Air …

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Performance Enhancement Of Raspberry Pi Server For The Application Of Oil Immersion Cooling, Dhaval Hitendra H Thakkar May 2016

Performance Enhancement Of Raspberry Pi Server For The Application Of Oil Immersion Cooling, Dhaval Hitendra H Thakkar

Mechanical and Aerospace Engineering Theses - Archive

The power consumed by Central Processing Unit (CPU) generates the heat which is undesirable and which is further responsible for the damage of Information Technology equipment. Oil Immersion cooling is one of the emerging technology which deals with the high server densities by submersing the servers in mineral oil. The study addresses the CFD analysis of Raspberry Pi computer servers with different cooling techniques and different modes of operating conditions. The thesis gives the explanation on the difference between air cooling and oil cooling with and without use of heat sinks. The study also shows the parametric analysis of heat …

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Parametric Cycle Analysis Of Adaptive Cycle Engine, Harinkumar Rajendrabhai Patel May 2016

Parametric Cycle Analysis Of Adaptive Cycle Engine, Harinkumar Rajendrabhai Patel

Mechanical and Aerospace Engineering Theses - Archive

One of the main area of research currently in air-breathing propulsion is increasing the fuel efficiency of engines. Increasing fuel efficiency of an air-breathing engine will be advantageous for civil transport as well as military aircraft. This objective can be achieved in several ways. Present design models are developed based on their uses: commercial transport, high range rescue aircraft, military aircraft. One of the main property of military aircraft is possessing high thrust but increasing fuel efficiency will also be advantageous resulting in more time in combat. Today's engine design operates best at their design point and has reduced thrust …

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Finite Element Based Weight Reduction Subject To Stability Constraints For An Airship Composite Duct, Soham M. Umbrajkar May 2016

Finite Element Based Weight Reduction Subject To Stability Constraints For An Airship Composite Duct, Soham M. Umbrajkar

Mechanical and Aerospace Engineering Theses - Archive

The primary functions of High Altitude Long Endurance (HALE) airships are persistent observation and wide area direct line of sight communication. Traditional airships have an ellipsoidal type hull, which is characterized by a large aspect ratio but results in an increase in the weight of the envelope. In order to reduce the weight of an airship, a hull having lower aspect ratio would be preferred. A novel unconventional airship design having a toroidal geometry with a propulsive duct running from the front end to back end was developed by Dancila in an attempt to achieve this objective. The propulsive duct …

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A Study Of Electrical Double Layer At An Aluminum Surface In An Automotive Cooling System, Saurabh Deobhankar May 2016

A Study Of Electrical Double Layer At An Aluminum Surface In An Automotive Cooling System, Saurabh Deobhankar

Mechanical and Aerospace Engineering Theses - Archive

Electrolytic corrosion is identified as a major problem which adversely affects the performance of a cooling system and hence compromises the performance of automobile with it. Electrolysis corrosion is a chemical reaction process that occurs between a metal surface and electrolyte. Mostly, the radiator tubes and tanks are made of aluminum with a high heat transfer rate. The coolant flows under pressure through the aluminum tubes, which gives rise to erosion-corrosion. The present thesis sheds light on the corrosion mechanism of Al 3003 alloy radiator tubes in contact with 50/50 ethylene glycol water coolant. The main objective is to understand …

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Cfd Modelling Of Wet Cooling Media And Design Optimization Of Heat Sink For Data Center Application, Shivang Yogeshkumar Desai May 2016

Cfd Modelling Of Wet Cooling Media And Design Optimization Of Heat Sink For Data Center Application, Shivang Yogeshkumar Desai

Mechanical and Aerospace Engineering Theses - Archive

Air cooling is most widely used and economical method of currently available cooling technologies in which heat exchanger plays a vital role in facility designs. Evaporative cooling can be energy efficient than mechanical cooling because it uses water’s enthalpy of vaporization. Wet cooling pads can be used as the direct evaporative cooling system in which pad is made of cellulose fibers those gets wet when water injected. When hot and dry air passes through pad surfaces, water evaporates in the air which cools down air adiabatically increasing humidity. These type of cooling units can be installed in these type of …

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Design And Parametric Analysis Of Flow Control Device For Dynamic Cold Plate To Optimize The Temperature Fluctuations Of The Multi-Chip Module, Avinash Veluturla May 2016

Design And Parametric Analysis Of Flow Control Device For Dynamic Cold Plate To Optimize The Temperature Fluctuations Of The Multi-Chip Module, Avinash Veluturla

Mechanical and Aerospace Engineering Theses - Archive

Continuing trends of increasing microprocessor power densities and non-uniform temperature distribution pose a significant challenge to the data center cooling. The most usual approach to data center cooling is air cooling but there are certain limitations to that approach. Major limitation is heat transfer coefficient so in order to overcome those limitations, we came up with liquid cooling using water as coolant. To minimize energy consumption of cooling system the objective is to design a dynamic energy efficient and practical cooling solution for high power equipment. Multi-chip module is used as the base for the liquid cooling solution. The main …

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Computational Analysis Of Impact Loading On Wafer Level Chip Scale Packages Mounted On Printed Circuit Boards Of Varying Thickness, Anik Mahmood May 2016

Computational Analysis Of Impact Loading On Wafer Level Chip Scale Packages Mounted On Printed Circuit Boards Of Varying Thickness, Anik Mahmood

Mechanical and Aerospace Engineering Theses - Archive

In the electronic industry one of the popular package is Chip Scale Package (CSP) due to its small form factor and low cost. To meet the need of new functionality and portability of the recent devices, CSPs’ have been most favorable choice for a long time. On the other hand, with the miniaturization process of these portable devices there is a growing risk of drop impact failure in day to day use. It’s not only the mechanical loading that is affecting the reliability of these devices but also thermal and thermo-mechanical loads are acting simultaneously. To analyze and ensure the …

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Evaluation Of Cooling Architectures And Control Strategies In Airflow Provisioning A Modular Data Center, Jaykishankumar Kunjbihari Patel May 2016

Evaluation Of Cooling Architectures And Control Strategies In Airflow Provisioning A Modular Data Center, Jaykishankumar Kunjbihari Patel

Mechanical and Aerospace Engineering Theses - Archive

To achieve energy efficiency and reduce operational costs in data centers with modularized Information Technology and cooling infrastructure there is an ongoing trend to minimize the use of mechanical cooling and instead use outdoor air in favorable environmental conditions for cooling purposes. The cooling module can comprise of evaporative cooling systems which use direct, indirect or a combination of direct/indirect evaporative cooling units to provide adequate cooling. The degree of cooling achieved in the IT module depends on the effective airflow provisioned and the air distribution methods employed. In this study, a modular data center which is equipped with a …

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Cfd Based Design And Optimization Of Louver Blade Angles To Enhance Better Air Flow Distribution And Improve Thermal Efficiency Of It Equipment In Data Centers, Avinash Kumar Ray May 2016

Cfd Based Design And Optimization Of Louver Blade Angles To Enhance Better Air Flow Distribution And Improve Thermal Efficiency Of It Equipment In Data Centers, Avinash Kumar Ray

Mechanical and Aerospace Engineering Theses - Archive

A data center is a depository which stores, processes and distribute large amounts of data and information using computer systems and associated components for power supplies, cooling systems. Modular data center is a portable method of deploying traditional large data center capacity into a small portable unit. According to the Uptime Institute, the amount of heat generated inside IT equipment has been increasing significantly. Data centers are using nearly 60% of their power in employing expensive cooling techniques. In addition, the cost of cooling has necessitated a need to reduce or eliminate mechanical cooling. As such, Air Economization, Direct and …

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Development Of Paraffin Wax As A Phase Change Material For Thermal Management In Electronic Systems, Aditya Pinto May 2016

Development Of Paraffin Wax As A Phase Change Material For Thermal Management In Electronic Systems, Aditya Pinto

Mechanical and Aerospace Engineering Theses - Archive

Increasing development in electronic technologies has improved functionality and reduced physical constraints, while managing to impart higher power and performance in smaller and compact devices. As a result of this size reduction, there is also a reduction in the surface area required for heat dissipation. Due to this the thermal management problem has been further intensified. The end result is that the power density continues to rise even with improved thermal management strategies incorporated into the system. Thermal management hence plays an important aspect especially when the design of compact electronic devices is concerned. For most electronic applications thermal loads …

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Design Consideration And Steady State Study Of Thrust Bearings In High Speed Subsonic Applications, Arvind Prabhakar May 2016

Design Consideration And Steady State Study Of Thrust Bearings In High Speed Subsonic Applications, Arvind Prabhakar

Mechanical and Aerospace Engineering Theses - Archive

Thrust bearings are required to perform at high speeds in various turbomachinery applications causing the nature of fluid flow within the bearings to be in high subsonic as well as supersonic regimes. The motivation of this research is to develop a bearing performance prediction model tailored for high subsonic speeds and large Reynolds numbers. The prime fluid characteristics studied in the thin film for predicting the bearing performance has been achieved by carefully considering inertial, viscous as well as compressible effects within the thin film fluid flow. Fluid inertia is a vital physical phenomenon that plays an important role in …

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Computational Study And Error Analysis Of An Integrated Sampling-Probe And Gas-Analyzer For Mixing Measurements In Supersonic Flows, Wenbo Zhu May 2016

Computational Study And Error Analysis Of An Integrated Sampling-Probe And Gas-Analyzer For Mixing Measurements In Supersonic Flows, Wenbo Zhu

Mechanical and Aerospace Engineering Theses - Archive

Concentration probes are employed in supersonic flow mixing experiments for binary gas mixture composition measurements. These measurements are fundamental for the advancement of the scramjet technology. While non-intrusive laser-based methods (such as planar laser-induced fluorescence and filtered Rayleigh scattering) have been developed greatly over the past few decades, intrusive methods (such as concentration probes) still play an essential role in the measurement of mixture composition due to the fact that, with correct application, they do not require further assumptions on the aerothermodynamic states of the investigated mixture, which are often difficult to corroborate. Conversely, such assumptions are essential to the …

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Investigation Of Additive Manufacturing Using Industrial Robots, Matt Heuser May 2016

Investigation Of Additive Manufacturing Using Industrial Robots, Matt Heuser

Mechanical and Aerospace Engineering Theses - Archive

Conventional additive manufacturing platforms are controlled using G-code, a numerical control language used to define the process parameters and move- ment of the print head. First, a digital model of the desired shape is created using 3-D computer graphics software. Then the model is analyzed by software tools that generate the necessary G-code instructions to be used by a 3-D printer to produce the desired object. The goal of this research is to lay the foundation and develop the necessary tools to 3-D print custom objects based on the viscous extrusion process using industrial robots. The first task is to …

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Computational Study Of Differential Capacitance-Double Layer Relationship In A Supercapacitor, Pranav Milind Phadtare May 2016

Computational Study Of Differential Capacitance-Double Layer Relationship In A Supercapacitor, Pranav Milind Phadtare

Mechanical and Aerospace Engineering Theses - Archive

Energy crisis is one of the most pressing problems that the world is facing. It involves a number of issues to be addressed in energy sources, transportation, storage, etc. Novel ways of energy storage are being actively explored. Electrical energy is stored by using devices such as batteries, capacitors, supercapacitors, etc. Supercapacitor seems to be a promising technology for this purpose. Traditionally, batteries have high energy densities but low power delivering density. On the other hand, conventional capacitors are capable of delivering high power densities but possess low energy storage density. Supercapacitors are a bridge between the two devices. Of …

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A Comparative Study Of The Thermo-Mechanical Behavior Of Wcsp Assembly Due To Difference In Pcbs’ Layer Thickness, Trina Barua May 2016

A Comparative Study Of The Thermo-Mechanical Behavior Of Wcsp Assembly Due To Difference In Pcbs’ Layer Thickness, Trina Barua

Mechanical and Aerospace Engineering Theses - Archive

The reliability of Chip Scale Package assembly is of great concern for the electronic industry. Due to multiple function integration of the present devices there is a high demand of ultra-miniaturization of the integrated parts to build the inside circuit assembly. Wafer Level Chip Scale Packages (WLCSP) are used in the industry to meet the challenges of these miniaturization due to its form factor, not so high cost and packaging efficiency which is also very high despite the known and unknown reliability issues. WLSCPs use packaging technology at the wafer level which is an extension of the wafer fab process …

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Determining Intruder Aircraft Position Using Series Of Stereoscopic 2-D Images, Aditya Ramani May 2016

Determining Intruder Aircraft Position Using Series Of Stereoscopic 2-D Images, Aditya Ramani

Mechanical and Aerospace Engineering Theses - Archive

Introduction of UAV (Unmanned Aerial Vehicles) into the NAS (National Air Space) requires the detect-and-avoid capability. That is, an aircraft should be able to detect other aircraft flying in the same airspace volume and make evasive maneuvers if there is potential conflict. One potential methods currently investigated for detection of an intruder aircraft is to process digital images taken by onboard cameras. When and if intruder aircraft detection is successful through image processing, avoidance algorithms can greatly benefit from the relative position information. This thesis research investigates methods to compute the position of an intruder aircraft relative to an observer …

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Numerical Study On Morphology And Solidification Characteristics Of Successive Droplet Depositions On A Substrate, Vimalan Adaikalanathan May 2016

Numerical Study On Morphology And Solidification Characteristics Of Successive Droplet Depositions On A Substrate, Vimalan Adaikalanathan

Mechanical and Aerospace Engineering Theses - Archive

Successive droplet impingement finds extensive applications in additive manufacturing technologies such as 3D printing, Liquid Metal Jetting and Net Form Manufacturing. Deposition, deformation and solidification of droplets are the constitutive stages in the process which determine the final outcome. Detailed knowledge about the flow behaviour, phase transformation and free surface deformation is required to have a complete understanding and optimization of the process parameters. Experimental research in this field is only limited to imaging techniques and post solidification analysis which only provide superficial information while overlooking most of the governing phenomenon. Knowledge of the physics governing the fluid and thermal …

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