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2018

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Articles 4201 - 4230 of 8951

Full-Text Articles in Engineering

Reliability Of A 2.5d Tsv Package, Neha Vinayak Gaikwad May 2018

Reliability Of A 2.5d Tsv Package, Neha Vinayak Gaikwad

Mechanical and Aerospace Engineering Theses - Archive

In the recent years, the Through Silicon Vias (TSVs) are helping a huge variety of the 3D IC and the 2.5D IC packaging applications to try to fulfill their requirements of functionality and higher connectivity at the expense of lower power consumption and minimum heat dissipation. The TSVs offer great interconnect density, high device density, short connection paths, great space efficiency and high interconnect bandwidth. The basic difference between a 3D TSV package and a 2.5D TSV package is that the 2.5D one interconnects the dies side by side on a silicon interposer, over its entire length. The interposer, placed …

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Mass Fabrication & Evolution Of Beads On Fiber, Kirthika Suresh May 2018

Mass Fabrication & Evolution Of Beads On Fiber, Kirthika Suresh

Mechanical and Aerospace Engineering Theses - Archive

In this work, we systematically explore the relation between the coating speeds and the finally formed liquid beads on fiber. The main focus of the paper lies with contact angle, length and height of beads on fiber and the fiber drawing velocity. For this purpose, free energy variation method is applied, based upon which the boundary conditions for the beads-on-fiber system and governing equations were re-derived. A combination of both, first and the second kind of the Legendre’s elliptical functions are used to determine the geometrical shape of the beads. Contact angle is extracted from the experimental data by using …

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Predicting Mechanical Behavior Of 3d Printed Structures Using Mechanics Of Composites And Fracture, Megha Tangri May 2018

Predicting Mechanical Behavior Of 3d Printed Structures Using Mechanics Of Composites And Fracture, Megha Tangri

Mechanical and Aerospace Engineering Theses - Archive

Recently, additive manufacturing, or 3D printing as it is more commonly called, has taken a big leap in the manufacturing industry. This technology is rapidly moving from prototyping to manufacturing using metals, polymers, concrete and even composites. Unlike subtractive methods of manufacturing, additive manufacturing can be used to manufacture parts with highly directional mechanical properties. This research focuses on predicting tensile failure of 3D printed polymer structures in different raster orientations using composites lamination theory. Previously it was found experimentally that tensile strengths of 3D printed specimens decrease when raster orientations changes from 0° to 90°. The proposed model developed …

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Numerical Simulation Of Unsteady Normal Detonation Combustion, Ajjay Omprakas May 2018

Numerical Simulation Of Unsteady Normal Detonation Combustion, Ajjay Omprakas

Mechanical and Aerospace Engineering Theses - Archive

The objective of this research is to simulate normal detonation combustion which is a mode of operation for a Pulsed Detonation Engine (PDE). A supersonic flow with stoichiometric hydrogen-air mixture is made to impinge on a wedge, thus resulting in increasing the temperature and pressure across a shock wave leading to the formation of detonation wave. Different modes of the operations can be simulated by varying the incoming Mach number, pressure, temperature and equivalence ratio. For the case of normal detonation wave mode which is an unsteady process, after the detonation being initiated due to the shock induced by the …

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Experimental And Analytical Study Of A Self-Regulated Flow Control Device Developed For Dynamic Cold-Plates To Cool High-Power Density Multi-Chip Modules, Rishi Ruben Palanikumar May 2018

Experimental And Analytical Study Of A Self-Regulated Flow Control Device Developed For Dynamic Cold-Plates To Cool High-Power Density Multi-Chip Modules, Rishi Ruben Palanikumar

Mechanical and Aerospace Engineering Theses - Archive

Modern high-power density modules often demand high amounts of power be invested in their cooling processes. Uneven heating at the chip level creates hotspots and temperature gradients across the module. A very effective way to conserve pumping power and address hotspots on the module is by targeted delivery of liquid coolant. One way to enable such targeted delivery of coolant is by using dynamic cold-plates (DCP) coupled with self-regulated flow control devices. This paper deals with the optimization and characterization of one such flow control device (FCD). The self-regulated FCD is actuated by a heat reactive shape memory alloy, Nitinol. …

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Comparison Of Nonlinear Filters For An Autonomous Lunar Mission Using Existing Navigation Techniques, Matthew David Shaver May 2018

Comparison Of Nonlinear Filters For An Autonomous Lunar Mission Using Existing Navigation Techniques, Matthew David Shaver

Mechanical and Aerospace Engineering Theses - Archive

Navigation systems play an important role for autonomous spacecraft. Earth based navigation systems such as GPS provide accurate positioning for orbiting spacecraft. In the case of lunar orbit, GPS is not available so other navigation techniques have to be used. This thesis proposes a novel idea to use Laser Ranging Retroreflectors, placed on the Moon's surface during the Apollo program, as a means of providing position information to an orbiting autonomous spacecraft. An Inertial Navigation System consisting of fusion of LRRR position data and Inertial Measurement Unit providing gyro and accelerometer data will be utilized during orbit about the Moon. …

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Impact Of Thermal Aging On Crack Growth Behavior Of Lead Free Solder Interconnects, Anuraag Girish Karnik May 2018

Impact Of Thermal Aging On Crack Growth Behavior Of Lead Free Solder Interconnects, Anuraag Girish Karnik

Mechanical and Aerospace Engineering Theses - Archive

Reliability assessment helps in better performance of electronic packages. This also helps electronic device manufacturing company as well as the users to evaluate the life of any device. The microstructure, mechanical response, and failure behavior of Pb-free solder joints in electronic assemblies are constantly evolving when exposed to isothermal aging and/or thermal cycling environments. Due to reflow process or exposure to harsh environment conditions, packages are subject to fatigue loads which can accelerate crack growth in the solder interconnects. But, some material after aging get hardened and decrease in plastic deformation capacity. This effect sometimes leads to better crack resistance …

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Finite Element Analysis Of Composite Reactor Pressure Vessel, Tejas Vasant Mhetre May 2018

Finite Element Analysis Of Composite Reactor Pressure Vessel, Tejas Vasant Mhetre

Mechanical and Aerospace Engineering Theses - Archive

Reactor Pressure Vessel is the container designed to hold gases or liquids above atmospheric pressure. The focus of this study is to develop Finite Element Model to predict the performance of composite reactor pressure vessel subjected to extreme pressure and temperature and compare with pressure vessel manufactured using conventional materials. In the first part of the study, a pressure vessel system with Carbon steel material under design pressure and temperature have been analyzed for stresses, deformation and Safety Factor. Various loading cases have been discussed during the analysis of pressure vessel. Composite materials have been a suitable replacement to the …

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Development And Validation Of The Deliquescent Relative Humidity Test Method For The Accumulated Particulate Matter Found In A Data Center Utilizing An Airside Economizer, Roshan Anand May 2018

Development And Validation Of The Deliquescent Relative Humidity Test Method For The Accumulated Particulate Matter Found In A Data Center Utilizing An Airside Economizer, Roshan Anand

Mechanical and Aerospace Engineering Theses - Archive

Data centers are virtual or physical infrastructure utilized by enterprises to house computer, server and networking systems and other vital components for the needs of the company’s information technology mainly serving the purpose of storing, processing and serving large amounts of mission critical data to clients. As data centers house a network’s most critical systems and are extremely vital for the continuity of daily operations, every organization prioritizes the reliability and security of data centers and their information. A remarkable amount of data center energy is consumed in eliminating the heat generated by Information Technology (IT) equipment to maintain and …

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Accelerated Thermal Cycling Of Printed Circuit Board For Single Phase Immersion Cooling Systems, Surya Duraisamy Asokan May 2018

Accelerated Thermal Cycling Of Printed Circuit Board For Single Phase Immersion Cooling Systems, Surya Duraisamy Asokan

Mechanical and Aerospace Engineering Theses - Archive

The adoption of immersion cooling of data center over conventional air-cooling is one among the more up to date advances that individuals have begun embracing to. Acknowledgement of Single phase Liquid Immersion cooling (Sp-LIC) of Information Technology equipment gives proficient cooling frameworks and significant vitality energy savings. This study centers on the unwavering reliability assessment in analyzing the material property of Printed Circuit Board (PCB) and performing Scanning Electron Microscope (SEM) scanning of the samples for any penetration of liquids into PCB. The Accelerated Thermal Cycling (ATC) test in view of ATC JEDEC is relevant just for air cooling. The …

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Human Robot Interaction With Cloud Assisted Voice Control And Vision System, Ravi Patel May 2018

Human Robot Interaction With Cloud Assisted Voice Control And Vision System, Ravi Patel

Mechanical and Aerospace Engineering Theses - Archive

The objective of this research is to investigate a way of interaction between humans and robots, which is through voice or speech commands. A Biomimetic Artificial Hand (BAH) is used as a platform to perform grasping tasks using human voice as an interacting and instructing medium between humans and robots. It is a hands-free approach of issuing commands to the BAH since it does not require the user to wear any specialized equipment. Previous research has shown difficulties in recognizing more than one word, database management for stored voice, and requirement of sufficient computing power. National Instruments software LabVIEW and …

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Solder Joint Design Optimization Of Quad-Flat Package With Gullwing Leads Under Accelerated Thermal Cycling And Power Cycling, Pranav Nikam May 2018

Solder Joint Design Optimization Of Quad-Flat Package With Gullwing Leads Under Accelerated Thermal Cycling And Power Cycling, Pranav Nikam

Mechanical and Aerospace Engineering Theses - Archive

Ever growing complexity in designing of Integrated Circuits and accommodating high number of Interconnections in the device is the main source of motivation in today’s world of IC devices. Quad Flat Package (QFP) with Gullwing leads is spearhead technology which enables high connectivity levels required to be customized in most convenient and advantageous form. Gullwing leads have the advantage of having a large area in contact with solder and also work as mechanical springs. They also make it easier to inspect and rework. Lot of work has been carried out on inspecting the reliability of solder joints in QFP packages …

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Experimental And Numerical Investigation Of Heat Transfer In Battery Pack Of A Hoverboard, Abhinav Prasad May 2018

Experimental And Numerical Investigation Of Heat Transfer In Battery Pack Of A Hoverboard, Abhinav Prasad

Mechanical and Aerospace Engineering Theses - Archive

Li-ion cells are used for energy storage and conversion in electric vehicles and a variety of consumer devices such as hoverboards. Performance and safety of such devices is severely affected by overheating of Li-ion cells in aggressive operating conditions. Several accidents due to fire in the battery pack of a hoverboard have been reported in the recent past. Despite the large number of hoverboards in use worldwide, there is a lack of systematic research on heat transfer in battery packs of hoverboards. This study presents experimental and numerical analysis of heat transfer in Li-ion battery pack of a hoverboard to …

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Study Of The Effect Of Humidity On Thermal Cycling Of A Ball Grid Array (Bga) Package, Samuel Terrence Ambosta May 2018

Study Of The Effect Of Humidity On Thermal Cycling Of A Ball Grid Array (Bga) Package, Samuel Terrence Ambosta

Mechanical and Aerospace Engineering Theses - Archive

Thermal Cycling (TC) Test is one of the most important reliability tests in the packaging and semiconductor industry. Humidity on the other hand is one of the significant factors for the reliability of packages, since there are several failures due to moisture absorption in packages. Humidity in packages can lead to soften them and decrease adhesive strength resulting into delamination near the solder tip and wire bond joint, which results in poor electric performance as well as reduced mechanical reliability. In addition, decrease in adhesive strength also causes corrosion in that area which leads to package failure. Absorption of humidity …

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Comparison Of Steel And Composite Rail Axle By Finite Element Analysis, Samip Nikulbhai Shah May 2018

Comparison Of Steel And Composite Rail Axle By Finite Element Analysis, Samip Nikulbhai Shah

Mechanical and Aerospace Engineering Theses - Archive

Axles are one of the most important railway vehicle parts that supports the weight of both vehicle and passenger. Failure in Axle in its operating condition may cause heavy damage to the passenger and car as well, hence high strength design is required to mitigate the possibilities of axle failure. Generally steel axle is used in rail industry, nowadays there are more interest to replace steel axle to the composite axle. Use of advanced composite material such as Kevlar, graphite-fiber, carbon-fiber and glass-fiber with proper resin core resulted in remarkable achievements because of its specific strength and improve fatigue, specific …

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Trust Based Time-Varying Network Topology For Distributed Co-Operative Control Of Multi-Class Multi-Agent Systems, Ankur Vipulkumar Dalal May 2018

Trust Based Time-Varying Network Topology For Distributed Co-Operative Control Of Multi-Class Multi-Agent Systems, Ankur Vipulkumar Dalal

Mechanical and Aerospace Engineering Theses - Archive

With increased levels of autonomy in most of the engineering fields and booms in areas such as swarms, platoons and Internet of Things (IoT), communication and information flow has become a highly researched field. With advancements in autonomous vehicles (AVs) and drones in armed warfare, more and more focus is being laid on intercommunication between these vehicles and its surroundings as well as intra-communication among the fleets/swarms itself. It is easier to deal with individual agents whereas it is quite challenging to deal with multi-agent systems especially with highly dynamic agents. In this thesis, we propose a general protocol for …

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Dynamics And Control Of Jumping Legged Robot, Gurashish Singh May 2018

Dynamics And Control Of Jumping Legged Robot, Gurashish Singh

Mechanical and Aerospace Engineering Theses - Archive

This research aims to studying the agility of legged robots particularly their interactions with the ground and achieve a jumping motion by using an operational space controller. Methods were developed to first formulate the equations of motions of the full system. Then we used the published impact and contact analytical framework to detect simultaneous, indeterminate impact and transition to contact with friction and addressed the well-known issues with energy consistency when using rigid body models for dynamic systems (i.e. there are no unusual gains in the energy after impact has ended). Non-penetration of the ground was achieved through online constraint …

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Characterization Of A Cold Plate By Experimental Analysis And Power Savings Calculation Of Dynamic Cold Plate, Barath Ragul Manimaran May 2018

Characterization Of A Cold Plate By Experimental Analysis And Power Savings Calculation Of Dynamic Cold Plate, Barath Ragul Manimaran

Mechanical and Aerospace Engineering Theses - Archive

Cooling is a critical part of data center’s infrastructure, and with ongoing demands in data processing and storage, thermal management issues are of great concern. Some imperative methods of removing heat are either using air or liquid (preferably water or refrigerant). When high power densities modules are involved, liquid cooling addresses some of the problems faced by air cooling as liquid coolants have higher thermal capacitance. Also, in the case of multi-chip modules, a non-uniform heating due to multicore generates hotspots and increases temperature gradients across the module. A dynamic cold plate was developed to address these issues with the …

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Monitoring Calcification In Rigid Wet Cooling Media Used In Direct Evaporative Cooling Of Data Centers., Hemanth Narayan Dakshinamurthy May 2018

Monitoring Calcification In Rigid Wet Cooling Media Used In Direct Evaporative Cooling Of Data Centers., Hemanth Narayan Dakshinamurthy

Mechanical and Aerospace Engineering Theses - Archive

Rigid wet cooling media is a key component of direct and indirect evaporative cooling systems. Evaporation is the process of a substance in a liquid state changing to a gaseous state. When water evaporates only H2O molecules gets evaporated and the other chemicals in the water is left behind on the surface as residue. Soul concentration is to determine how calcium scale affects the overall performance i.e. saturation efficiency and pressure drop across the media pad. An Accelerated Degradation Testing by rapid wetting and drying on the media pads at elevated levels of calcium was planned on the media pad. …

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Thermal Degradation Of Passive Components For Use In Single Phase Immersion Cooling Application, Keerthivasan Padmanaban May 2018

Thermal Degradation Of Passive Components For Use In Single Phase Immersion Cooling Application, Keerthivasan Padmanaban

Mechanical and Aerospace Engineering Theses - Archive

The growth in the computing and data industry demands high-performance data centers where the thermal management issues are of greater concern. A cooling system paradigm using the immersion cooling technology is a more reliable and effective method. In immersion cooling, servers are directly submerged into a dielectric fluid. A comparative study on the reliability of the passive components cooled by air, mineral oil and EC-100 was carried out. The Accelerated Thermal Cycling test based on ATC JEDEC is applicable only for air cooling. The ASTM standards D 3455 with some suitable modification was adopted to test the material compatibility with …

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3d Printed Force Transducers For In-Vitro Mitral Valve Chordae Tendineae Force Measurements, Hayley Chandler May 2018

3d Printed Force Transducers For In-Vitro Mitral Valve Chordae Tendineae Force Measurements, Hayley Chandler

Biomedical Engineering Undergraduate Honors Theses

Mitral valve surgery is incredibly prevalent in the United States with more than 40,000 mitral valve surgical procedures annually. Improving the imaging techniques used to diagnose these cases requires validation of 3D models through experimental data such as mechanical properties of the tissue. An essential part of this process for the mitral valve is measuring the force experienced by chordae tendineae. This has been achieved with brass force transducers but using a 3D printed design can have many benefits. In this study, 3D printed miniature c-shaped force transducers comparable to previous metal models were designed and created using Solidworks 2016. …

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Measurement Of The Thermal Performance Of A Single-Phase Immersion Cooled Server At Elevated Temperatures For Prolonged Time, Pratik Vithoba Bansode May 2018

Measurement Of The Thermal Performance Of A Single-Phase Immersion Cooled Server At Elevated Temperatures For Prolonged Time, Pratik Vithoba Bansode

Mechanical and Aerospace Engineering Theses - Archive

Fully immersion of servers in electrically non-conductive (dielectric) fluid has recently become a promising technique for minimizing cooling energy consumption in data centers. The improved thermal properties of these dielectric fluids facilitate considerable savings in both upfront and operating cost over traditional air-cooling. This technology provides an opportunity for accommodating increased power densities. It also minimizes and addresses the common operational issues of air cooling methods like overheating and temperature swing in the system, fan failures, dust, air quality, and corrosion. This paper presents various data about the performance of a fully single-phase dielectric fluid immersed server over wide temperature …

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Computational Fluid Dynamics Simulation-Based Artificial Neural Network Modelling For Data Center Cooling Prediction, Nikita Ravindra Sukthankar May 2018

Computational Fluid Dynamics Simulation-Based Artificial Neural Network Modelling For Data Center Cooling Prediction, Nikita Ravindra Sukthankar

Mechanical and Aerospace Engineering Theses - Archive

Continuous provision of quality supply air to data center’s IT pod room is key parameter in assuring effective data center operation without any down time. Due to number of possible operating conditions and non-linear relations between operating parameters make the working mechanism of data center difficult to optimize energy use. At present industries are using computational fluid dynamics (CFD) to simulate thermal behaviour for all types of operating conditions. The focus of this study is to predict Supply Air Temperature using Artificial Neural Network(ANN) which can overcome limitations of CFD such as high cost, need of expertise and large computation …

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Cfd Analysis Of Thermal Shadowing And Optimization Of Heat Sinks In 3rd Generation Open Compute Server For Single Phase Immersion Cooling Applications, Ravya Dandamudi May 2018

Cfd Analysis Of Thermal Shadowing And Optimization Of Heat Sinks In 3rd Generation Open Compute Server For Single Phase Immersion Cooling Applications, Ravya Dandamudi

Mechanical and Aerospace Engineering Theses - Archive

In today’s networking world, utilization of servers and data center has been increasing significantly. Increasing demands of processing and storage of data causes corresponding increase in power density of servers. The data center energy efficiency largely depends on thermal management of servers. Currently, air cooling is the most widely used thermal management technology in data centers. However, air cooling is starting to reach its limits due to very high-powered microprocessors and packaging. To overcome the limitations of air cooling in data centers, operators are moving towards immersion cooling using different dielectric fluids. Thermal shadowing is the effect in which temperature …

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Analysis And Comparison Between A Conventional Metal And A Metal-Composite Marine Propeller Shaft, Kaushal Mayankkumar Shah May 2018

Analysis And Comparison Between A Conventional Metal And A Metal-Composite Marine Propeller Shaft, Kaushal Mayankkumar Shah

Mechanical and Aerospace Engineering Theses - Archive

The basic principal of a ship propulsion is the reactive (thrust) force generated by the propellers against the stream of water which forces the ship to propel in the opposite direction. The Shafting system is thus required to transmit the necessary torque to the propeller at a certain speed. Studies have suggested that shafts are the most common reason of failures among the whole marine propulsion system comprising of the main engine and propeller apart from the shaft. Stress concentration and torsional vibrations are the two major causes of failure in the propulsion shafting systems based on the case study …

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Comparison Of Steel And Composite Leaf Springs Using Fea, Prashik Sunil Gaikwad May 2018

Comparison Of Steel And Composite Leaf Springs Using Fea, Prashik Sunil Gaikwad

Mechanical and Aerospace Engineering Theses - Archive

Composite materials are widely used in aeronautical, marine and automotive industries, because of their excellent mechanical properties, low density and ease of manufacture. Due to this increasing trend to utilize composite materials, it has become necessary to investigate the pros and cons of composites. Increasing competition and innovation in automobile sector tends to modify the existing products by new and advanced material products. A suspension system of vehicle is also an area where these innovations are carried out regularly. Leaf springs are one of the oldest suspension components that are being still used widely in automobiles. They contribute to 15-20% …

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Experimental Analysis Of The Effects Of Single-Phase Immersion Cooling Of Optical Interconnects On Mechanical Properties Of Active Optical Cables, Hrishabh Singh May 2018

Experimental Analysis Of The Effects Of Single-Phase Immersion Cooling Of Optical Interconnects On Mechanical Properties Of Active Optical Cables, Hrishabh Singh

Mechanical and Aerospace Engineering Theses - Archive

Active optical cables (AOC) are being increasingly adopted for data communication and storage, networking, and high-performance computing (HPC) applications. However, their ability to meet higher data-rate requirements necessitates increased heat dissipation demands in fiberoptic datacom systems. Many dielectric coolants having heat capacities much higher than that of air are available in the market. However, there is a lack of literature and data on the reliability of using single-phase dielectric fluids for immersion-cooling of inter and intra-rack optical interconnections in data centers. Industry standards and prevalent aging test methods for optical cables prove insufficient as they do not address immersion in …

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Study Of Copper-Rich Intermetallic Phase Formation In Copper-Aluminum Binary System, Valery Georges Ouvarov-Bancalero May 2018

Study Of Copper-Rich Intermetallic Phase Formation In Copper-Aluminum Binary System, Valery Georges Ouvarov-Bancalero

Material Science and Engineering Dissertations - Archive

This work aims to study the initial formation and subsequent growth of intermetallic compounds (IMC) in the binary Al-Cu system. Al-Cu pair configurations have been successfully used for several decades as structural components, and extensive research on their mechanical and metallurgical properties is available. More recently, the microelectronics industry started implementing the Cu wire-bond technology, which renewed the interest of the scientific community. As with every technological evolution, initial quality and reliability issues arose. Copper (Cu) wire to aluminum (Al) bond-pad is prone to crack nucleation leading to failure at the interface between Cu and Cu-rich IMCs. Even though numerous …

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Investigation Of Functional Connectivity And Neurovascular Coupling In Different Vigilance / Breath-Hold States Of The Brain From Simultaneous Eeg-Fnirs Measurements, Olajide Babawale May 2018

Investigation Of Functional Connectivity And Neurovascular Coupling In Different Vigilance / Breath-Hold States Of The Brain From Simultaneous Eeg-Fnirs Measurements, Olajide Babawale

Bioengineering Dissertations - Archive

Functional connectivity and neurovascular coupling are important phenomena that occur in the brain. Functional connectivity is the study of functional brain networks and their characteristics. While neurovascular coupling is the relationship or link between neuronal activity and corresponding cerebral blood flow in the brain. Up until now, both functional connectivity and neurovascular coupling have not been studied in different vigilance states of the brain from wakeful rest state to sleep state, using simultaneous EEG-fNIRS measurements. Also, the neurovascular coupling in different states of breath-holding has not been studied using simultaneous EEG-fNIRS measurements Therefore, my doctoral research utilized a whole-head simultaneous …

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An Investigation Of Water Pipeline Renewal Practices, Abbas Abed Salman May 2018

An Investigation Of Water Pipeline Renewal Practices, Abbas Abed Salman

Civil Engineering Theses - Archive

Globally, the use of trenchless technologies is gradually increasing due to the growing need to replace and renew aging utility infrastructure and the need for more flexible solutions for the installation of new pipes. In the United States of America, the American Society of Civil Engineers (ASCE) in 2017 assessed that America’s infrastructure is close to failing. It faces an annual shortfall of at least $11 billion to replace the aging facilities that are near the end of their useful lives. In this research, surveys and interviews of professionals working in trenchless technologies for the North American Society for Trenchless …

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