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Articles 1291 - 1320 of 2904

Full-Text Articles in Engineering

A Numerical Study Of Microfluidic Droplet Motions In Parallel-Plate Electrowetting-On-Dielectric (Ewod) Devices, Yin Guan Jan 2015

A Numerical Study Of Microfluidic Droplet Motions In Parallel-Plate Electrowetting-On-Dielectric (Ewod) Devices, Yin Guan

Mechanical and Aerospace Engineering Dissertations - Archive

Microscale water droplet motions in parallel-plate electrowetting-on-dielectric (EWOD) devices including transport, splitting, merging and dispensing have been numerically studied. The transient governing equations for the microfluidic flow are solved by a finite volume scheme with a two-step projection method on a fixed computational domain. The interface between liquid and gas is tracked by a coupled level set and volume-of-fluid (CLSVOF) method. A continuum surface force (CSF) model is employed to model the surface tension at the interface. Contact angle hysteresis which is an essential component in EWOD modeling is implemented together with a simplified model for the viscous stresses exerted …

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Feasibility Studies To Support Landfill Gas Recovery In Ghana, Neda Jangikhatoonabad Jan 2015

Feasibility Studies To Support Landfill Gas Recovery In Ghana, Neda Jangikhatoonabad

Civil Engineering Theses - Archive

According to World Bank Ghana generates 0.09 kg of solid waste per person per day, where there are only 4 engineered landfills in the country. In 2010, Ghana contributed to 0.13% of global greenhouse gases emissions, 10% of which was associated with waste sector. On the other hand, according to the World Bank in 2011, 39.5 % of Ghana’s population did not have access to electricity. Tapping landfill gas will not only provide portion of needed energy for the country, but will also help solve many of the environmental problems. Currently there is no landfill gas to energy project in …

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Using Lean Techniques To Reduce Waste And Improve Performance In Municipal Project Delivery, Yasir E. Abdelrazig Jan 2015

Using Lean Techniques To Reduce Waste And Improve Performance In Municipal Project Delivery, Yasir E. Abdelrazig

Civil Engineering Theses - Archive

The basic concepts of lean thinking in construction projects are to reduce waste, improve communication, and promote teamwork integration through a common set of tools and techniques. With increased demand for public works projects, there is a need to focus attention on the efficient delivery of construction project services in the public sector, and in particular, on municipal project delivery. Performance improvements using lean techniques are considered to overcome problems, facilitate project progress, and offer recommendations for better municipal construction project processes. Municipal projects are a part of the public works which include a broad category of infrastructure projects, financed …

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A Parametric Study Of The Effects Of Ɛ And ��̅ On The Poisson Boltzmann Equation For One And Two Spherical Particles Using A Boundary Integral Equation Method, Oumama H. Lingamfelter Jan 2015

A Parametric Study Of The Effects Of Ɛ And ��̅ On The Poisson Boltzmann Equation For One And Two Spherical Particles Using A Boundary Integral Equation Method, Oumama H. Lingamfelter

Civil Engineering Theses - Archive

Many biomolecules, such as DNA, exhibit properties that are dependent on their electrostatic interaction with an electrolytic solution. Both explicit atomistic and implicit continuum models have been developed to solve the electrostatic problem. The implicit models are based on the Poisson-Boltzmann (PB) equation, whose lower computational cost makes them favored for bio-molecular applications, particularly as the molecule size increases. Among the implicit models, a boundary integral equation (BIE) method involving only numerical treatment on a surface in turn is more efficient than domain-based finite element and finite difference methods. This is especially so in the present case where the electric …

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Comparison Of Post-Tensioned Cast In Place Concrete And Steel-Concrete Composite Bent Caps, Francisco David Berrocal Ruiz Jan 2015

Comparison Of Post-Tensioned Cast In Place Concrete And Steel-Concrete Composite Bent Caps, Francisco David Berrocal Ruiz

Civil Engineering Theses - Archive

Civil engineering projects are conditioned not only by the technology available but also by resources availability as well as budget and construction time. Special conditions applicable to particular projects can also control their development.The correct selection from the different feasible alternatives can determine the final output of a project. In that sense, the importance of bridge structures on both the overall budget and schedule of civil engineering projects makes the selection of the proper structural typology decisive for their success or failure. In some cases, special characteristics can establish the need of innovative solutions to guarantee a successful development of …

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Smart Speed Bumps, Mohammed Shakir Rajani Jan 2015

Smart Speed Bumps, Mohammed Shakir Rajani

Civil Engineering Theses - Archive

The research underscores the need and importance of traffic calming devices and provides the basis for designing and building a device for traffic calming in neighborhoods with high pedestrian traffic, particularly children. The thesis focuses on developing a traffic calming device that is responsive to driver behavior rather than a static traffic calming device. The design presented herein involves modifying conventional speed bumps used for calming traffic in areas with high pedestrian traffic. The relevant engineering issues that are addressed include:* The functional requirements of the overall system and each of the system components* Operational challenges* Testing framework for evaluating …

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Concrete Chloride Ingress: Effect Of Frp Type, Layers And Epoxy, Vinod Reddy Kamagani Kuntla Jan 2015

Concrete Chloride Ingress: Effect Of Frp Type, Layers And Epoxy, Vinod Reddy Kamagani Kuntla

Civil Engineering Theses - Archive

The main objective of this research is to reduce the chloride ingress in concrete due to the effects of Fiber Reinforced Polymer (FRP) type, layers and Epoxy. It has been established from previous researches that FRP wrap used to retrofit concrete structures offer a high resistance to chemical solutions but in this case study different variables like FRP, layers of FRP and only epoxy are used to know the resistance of concrete structures to chemical solutions. The ACI 318-11 Code allows for a reduction of clear cover depth if an equivalent clear cover depth can be establish. The FRP used …

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Development And Validation Of Tdr Based Sensors For Thermal Conductivity And Soil Suction Measurements, Nan Zhang Jan 2015

Development And Validation Of Tdr Based Sensors For Thermal Conductivity And Soil Suction Measurements, Nan Zhang

Civil Engineering Dissertations - Archive

Simultaneous measurement of soil thermal conductivity, moisture content, dry density and soil suction is a challenging issue and very important to the design of geothermal related structures such as geothermal energy piles (GEP), ground source heat pump (GSHP) systems borehole thermal energy storage (BTES) systems, etc. The measurement of these properties is mainly done in laboratory conditions which can be time consuming. Hence, an attempt is made in this research to determine a new field sensor that can provide these properties about time frame. TDR technique had been used successfully to measure soil moisture content and dry density by analyzing …

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Non-Invasive Biomedical Imaging And Radiobiology Investigations In Pre-Clinical Prostate Tumor Models, Derek A. White Jan 2015

Non-Invasive Biomedical Imaging And Radiobiology Investigations In Pre-Clinical Prostate Tumor Models, Derek A. White

Bioengineering Dissertations - Archive

Oxygen deficiency (hypoxia) in prostate tumors can hinder the biological effectiveness of radiotherapy. Therefore the ability to assess tumor hypoxia non-invasively in vivo in man could significantly improve therapy outcome. Magnetic resonance (MR) imaging is increasingly applied in clinical evaluation of prostate cancer. Therefore, an oxygen sensitive technique would be very attractive and the utility of oxygen-enhanced MRI (OE-MRI) has shown promise for predicting tumor growth delay in syngeneic rat prostate tumors following radiotherapy. In this dissertation, the overall goal was to investigate a potential imaging biomarker for predicting tumor response to image-guided radiotherapy (IGRT). First, I used in vivo …

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Development Of Atlas-Guided Diffuse Optical Tomography To Investigate Age-Dependent Human Cognitive Functions Under Risk Decision Making, Lin Li Jan 2015

Development Of Atlas-Guided Diffuse Optical Tomography To Investigate Age-Dependent Human Cognitive Functions Under Risk Decision Making, Lin Li

Bioengineering Dissertations - Archive

To better understand the age effect on neural correlates under risk decision-making stimulations, studies using advanced neuroimaging with a sufficient statistical power are desired. Diffuse optical tomography (DOT) of human brain functions is an emerging non-invasive neuroimaging technology. Compared to magnetic resonance imaging (MRI), DOT is more cost-effective, more portable, and easier to conduct studies targeting on different age groups. However, current DOT is limited by its low spatial resolution and depth accuracy. It is thus imperative to develop a technique that can improve imaging quality of DOT and be used to investigate age-dependent human brain functions under risk decision …

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Performance Of Full-Scale Ultra-High Performance Fiber-Reinforced Concrete Column Subjected To Extreme Earthquake-Type Loading And Effect Of Surface Preparation On The Cohesion And Friction Factors Of The Aashto Interface Shear Equation, Guillermo Palacios Jan 2015

Performance Of Full-Scale Ultra-High Performance Fiber-Reinforced Concrete Column Subjected To Extreme Earthquake-Type Loading And Effect Of Surface Preparation On The Cohesion And Friction Factors Of The Aashto Interface Shear Equation, Guillermo Palacios

Civil Engineering Theses - Archive

Buildings in areas of high seismicity may be subjected to large axial stresses as well as severe earthquake loading. In order to protect the integrity of these buildings, concrete columns must possess high compressive strength and adequate ductility. While the use of high strength concrete (HSC) may appear as an attractive alternative and can reduce the section size of first story columns, its increase in strength leads to an increase in brittleness compared to that of normal strength concrete. For that reason, HSC requires a large amount of transverse reinforcement to maintain adequate ductility, which leads to severe congestion in …

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An Investigation Of The Effect Of Obstructive Sleep Apnea On Cerebral Hemodynamics In Relation With Systemic Hemodynamics, Raichel Mary Alex Jan 2015

An Investigation Of The Effect Of Obstructive Sleep Apnea On Cerebral Hemodynamics In Relation With Systemic Hemodynamics, Raichel Mary Alex

Bioengineering Dissertations - Archive

Obstructive Sleep Apnea (OSA) is a major sleep disorder affecting approximately 18 million adults in the US. Recent studies have observed cognitive impairments and brain structural changes in OSA subjects where these deficits were related to peripheral hypoxia and sleep fragmentation. Nonetheless, underlying cerebral hemodynamics and cerebral oxygenation might play an important role in the development of these impairments. Hence, in this study it is hypothesized that 1) OSA induces significant variations in cerebral hemodynamics, and 2) level of variations in cerebral hemodynamics can be related to the changes in systemic hemodynamics. To test these hypotheses, 8 hours of nocturnal …

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Predicting Horizontal Pressure In 2-Stage Mse Structures, Thomas Patrick Taylor Jan 2015

Predicting Horizontal Pressure In 2-Stage Mse Structures, Thomas Patrick Taylor

Civil Engineering Theses - Archive

Mechanically Stabilized Earth (MSE) structures have been successfully used in the United States as embankment support structures for heavy highway transportation projects since 1972. On project sites that have poor foundations and where large settlements are predicated a variation of MSE called 2-Stage MSE is utilized. As the name suggests, 2-Stage structures are constructed in two stages. Stage-1 consists of constructing a flexible faced MSE structure and Stage-2 consists of attaching a veneer to the face of the Stage-1 structure. The Stage-1 and Stage-2 structures are separated by a short distance forming a cavity that is filled with granular material. …

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Experimental Evaluation Of Frp Strengthened Concrete Bridge Girders, Rakesh B. Jayanna Jan 2015

Experimental Evaluation Of Frp Strengthened Concrete Bridge Girders, Rakesh B. Jayanna

Civil Engineering Theses - Archive

This report presents the details of research study on the use of Carbon Fiber Reinforced Polymers (CFRP) sheets to strengthen the Pre-stressed concrete TxDOT Tx-28 bridge girders in flexure and shear. Four girders were subjected to destructive test in this research. First girder as control specimen without any CFRP applied on it, Second and third girders were flexural strengthened for one and two layers of CFRP and the forth girder is shear strengthened with one layer CFRP. Experimental phases along with the comparison of test results in terms of flexural and shear capacity of bridge girders, strains and deflections are …

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A Unified Swcc-Clay Mineralogy Based Framework For Predicting Swell Behavior Of Expansive Soils, Alejandro Hernan Pino Bravo Jan 2015

A Unified Swcc-Clay Mineralogy Based Framework For Predicting Swell Behavior Of Expansive Soils, Alejandro Hernan Pino Bravo

Civil Engineering Dissertations - Archive

Expansive soils are spread over different climatic zones around the world with varying mineralogical content and microstructure, making the soil to absorb moisture between their mineral layers and therefore undergo volume changes. This behavior generates swell and shrinkage surface movements which affect the integrity of infrastructure built on them. A practice currently employed correlates swell-shrink behavior to soil index parameters, however, variable soil mineralogy limits this approach, which generates poor soil swell characterization. Thus, characterizing efforts must be emphasized on identification of real parameters governing the swell/shrink behavior, such as mineralogy, variation of suction with moisture content and pore distribution. …

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The Strength Of Horizontal Shear Reinforcement With Limited Development, Regina Nyambura Waweru Jan 2015

The Strength Of Horizontal Shear Reinforcement With Limited Development, Regina Nyambura Waweru

Civil Engineering Dissertations - Archive

In order for the composite action between the precast beam and the cast-in-place deck to be effective, sufficient horizontal (interface) shear strength needs to be provided at the interface of the two concrete elements to prevent slip. Horizontal shear strength is provided by three main components: the protrusions on the crack faces (cohesion/aggregate interlock), friction between the faces resulting from the normal compressive stress, and the dowel action of the reinforcing bars. AASHTO LRFD equation assumes that all reinforcement crossing the interface would be fully developed on both sides of the interface at ultimate shear strength. This study examines if …

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Repair Of Impact-Damaged Prestressed Concrete Bridge Girder Using Glass Frp Rebar, Maria Angeles De La Flor Montero Jan 2015

Repair Of Impact-Damaged Prestressed Concrete Bridge Girder Using Glass Frp Rebar, Maria Angeles De La Flor Montero

Civil Engineering Theses - Archive

Overpass girders are risked by the impact of the traffic, over height vehicle, travelling under the structure, creating a hazard for the drivers over and under the bridge.When a bridge girder is damaged the repair solution adopted has to meet the following criteria:- Safety. The repaired structure has to provide a minimum level of service to guarantee the safety of the traffic during the life of the structure. - Repair time. To minimize the risk and the inconvenience for the traffic the repair time has to be minimum.- Economy. The adopted solution has not only to fulfill the previous requirements, …

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Enhanced Viscoelastic Modeling Of Hot Mix Asphalt, Tito P. Nyamuhokya Jan 2015

Enhanced Viscoelastic Modeling Of Hot Mix Asphalt, Tito P. Nyamuhokya

Civil Engineering Dissertations - Archive

The primary objective of this research is to investigate the relationships between Compressive (CDM) and Tensile Dynamic Moduli (TDM) of Hot Mix Asphalt (HMA) and develop a material model that predicts tensile dynamic modulus from known compressive dynamic modulus. Moreover, the research develops an enhanced visco-hyper-elastic Finite element model that incorporates both CDM and computed TDM to predict the structural response of a perpetual pavement structure subjected to wheel loading. In the laboratory, the Compressive and Tensile Dynamic Modulus parallel to the direction of compaction and Tensile dynamic modulus perpendicular to the direction of compaction were determined at different temperature …

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Image Segmentation Approach For Realizing Zoomable Streaming Hevc Video, Zarna Patel Jan 2015

Image Segmentation Approach For Realizing Zoomable Streaming Hevc Video, Zarna Patel

Electrical Engineering Theses - Archive

With increasing popularity of high resolution video format, video coding technology such as High Efficiency Video Coding (HEVC) which can provide a substantially higher compression capability than the existing H.264/AVC standard has received increased attention. HEVC is the next generation compression technology lauded as the enabler for a host of new services and capabilities. Recently, multimedia applications and their use have grown dramatically in popularity due to mobile device adoption by the consumer market. However, a crucial challenge is to provide a better user experience for browsing videos on the limited and heterogeneous screen sizes. Streaming of an arbitrary region …

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Real Time Surface Defect Measurement From Road Profile, Vivek Jolly Jan 2015

Real Time Surface Defect Measurement From Road Profile, Vivek Jolly

Electrical Engineering Theses - Archive

The Texas Department of Transportation (TxDOT) annually collects profile data over the state maintained highway network and uses the profile data to determine the ride quality based on a serviceability index (SI) and the International Roughness Index (IRI). The equation used at present to obtain the SI from the profile data is based on ride measurements from an old rating session in the 1960s. Several changes have taken place over the years that required re-evaluation of the ride equation, led to a TxDOT funded research in 2000 to evaluate the adequacy of the current equation. During this study, a new …

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Statistical Analysis Of Indoor Uwb Channel Parameters In Different Wall Corridors And Through-Wall Environments, Sreevinay Netrapala Jan 2015

Statistical Analysis Of Indoor Uwb Channel Parameters In Different Wall Corridors And Through-Wall Environments, Sreevinay Netrapala

Electrical Engineering Theses - Archive

The indoor channel parameters appears different for Ultra Wide Band (UWB) systems than it does to narrow band systems. Generally UWB pulses are short and do not overlap in time like multipath sine waves. According to electromagnetic theory, lower frequencies have better penetrating properties. The combination of larger spectrum and lower frequencies possessed by UWB signals makes it easy to penetrate through walls, floors, doors, wood, ceilings, etc. This penetration property plays a very important role in indoor UWB communication system. This thesis presents the statistical analysis of large scale, small scale and time dispersal parameters in different wall corridor …

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Realistic Interaction With Social Robots Via Facial Expressions And Neck-Eye Coordination, Sumit Kumar Das Jan 2015

Realistic Interaction With Social Robots Via Facial Expressions And Neck-Eye Coordination, Sumit Kumar Das

Electrical Engineering Theses - Archive

In this thesis, we report on research work concerning various aspects of interaction between an android head and its environment. The research aims at building a reusable framework of interaction through facial expressions and vision which can be used for a wide range of humanoid robotic heads. The framework contains specially programmed modules that enable the android head to effectively interact with its environment via facial expressions and neck-eye coordinated motion.The object detection and tracking module enables the android head to detect and track objects and users through coordinated motions of neck and eye. The module has the capability of …

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Motion Learning And Control For Social Robots In Human-Robot Interaction, Namrata Balakrishnan Jan 2015

Motion Learning And Control For Social Robots In Human-Robot Interaction, Namrata Balakrishnan

Electrical Engineering Theses - Archive

In the domain of social robotics, robots have recently been used in conversational interaction with humans. In this thesis, research was conducted to help create a system for imitation learning. In this system, a trainer trains a robot to be a teacher. The robotic teacher interacts with other humans in order to teach them the task that the robot was trained on. The method of `Teaching by Demonstration' was used, where an ideal motion is performed by a trainer. This ideal motion is learned by the robot and replayed in the subsequent interaction with humans. If the replayed motion is …

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Channel Estimation And Statistical Analysis Of Indoor Environment Using Ultrawideband Radio Technology, Shruthishree Bangalore Krishnamurthy Jan 2015

Channel Estimation And Statistical Analysis Of Indoor Environment Using Ultrawideband Radio Technology, Shruthishree Bangalore Krishnamurthy

Electrical Engineering Theses - Archive

Ultra-wideband technology finds various applications in radar technology, medical imaging, see-through-wall applications, surveillance and short distance communication applications. All of these applications require that the behavior of the channel be estimated giving a priori information about the various attributes of the channel like path loss, delay spread, channel capacity and so on. These parameters are the key to design an effective communication infrastructure suitable for the needs of the application.In this thesis, the main aim was to model the channel and extract the various parameters related to the channel through data processing methods. In particular, a classroom environment was chosen …

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Embedded Data Acquisition Platform For Surface Measurements On Wet Concrete, Anuja Raikar Jan 2015

Embedded Data Acquisition Platform For Surface Measurements On Wet Concrete, Anuja Raikar

Electrical Engineering Theses - Archive

The early detection of roughness over newly poured wet concrete allows correction of the surface before concrete is hardened. The smoothness of the wet concrete can be monitored and controlled at an early stage saving additional effort and cost. The goal of this research study is to examine the techniques to detect the roughness over the surface of wet cement concrete. A sliding profiler is one of the techniques which estimates profile of the surface based on the bumps detected on freshly poured concrete. This thesis focuses on the data acquired by the sliding profiler using a different measurement sensor …

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Improving Fracture Toughness Of Silicon Carbide Based Ceramics By Microstructure Tailoring, Sheikh Fahad Ferdous Jan 2015

Improving Fracture Toughness Of Silicon Carbide Based Ceramics By Microstructure Tailoring, Sheikh Fahad Ferdous

Mechanical and Aerospace Engineering Dissertations - Archive

Ceramic materials are one of the most promising materials for wide variety of technical applications such as automotive, aerospace, medical, and other applications. They have very high strengths and high melting points relative to metals. However, low fracture toughness is one of the main barriers of ceramics prohibiting their wide-spread applications. This is because ceramics are mainly bonded with directional bonds which don’t allow dislocations based deformation. Several attempts have been made to increase the toughness of ceramic materials without sacrificing significantly the other mechanical properties. Here three different types of SiC based ceramics have been computationally (atomistic and up-scaled …

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Novel Device And Methods For Composite Material Characterization, Michael M. Tadros Jan 2015

Novel Device And Methods For Composite Material Characterization, Michael M. Tadros

Mechanical and Aerospace Engineering Dissertations - Archive

Composite materials have several advantages over metallic materials, with their high specific strength and ability to be elastically tailored to create advantageous structural responses. However, the widespread implementation of composite materials in primary structures is limited by our knowledge of how damage mechanisms interact and spread inside composite parts. To date, characterization has been conducted using one of two methods, surface measurements and subsurface measurements. Surface measurements cannot in general capture the failure of multidirectional composite laminates. Subsurface measurements allow for observations of the internal material structure and damage mechanisms inside the composite which might facilitate greater understanding of the …

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Computational Analysis Of I.T. Rack Under Vibration Load, Framroz Meheryar Bharucha Jan 2015

Computational Analysis Of I.T. Rack Under Vibration Load, Framroz Meheryar Bharucha

Mechanical and Aerospace Engineering Theses - Archive

Structural failure of a rack due to vibration could result in injury to people, damage to IT equipment, or interruption of services that depend on proper functioning of the IT and networking equipment in the rack. In this topic, a computational study of an IT rack and a group of racks placed adjacent to each other under three vibration load scenarios: transportation, office and earthquake vibration is presented.Each rack can weigh as much as 1600 kg (3500 lb.) when fully populated with IT equipment. Two standards commonly used for testing racks with synthetic seismic loads are the GR-63-CORE Network Equipment …

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Performance Analysis Of A Helium Cooled Vhtr Powered Brayton Cycle Topping Unit On An Existing Steam Cycle Using Numerical Propulsion System Simulation, Warren Romao Caetano Freitas Jan 2015

Performance Analysis Of A Helium Cooled Vhtr Powered Brayton Cycle Topping Unit On An Existing Steam Cycle Using Numerical Propulsion System Simulation, Warren Romao Caetano Freitas

Mechanical and Aerospace Engineering Theses - Archive

With the decommissioning of ageing coal power plants due to outdated technology and high levels of air pollution, the advantages of overhauling existing infrastructure is twofold. First, by providing an alternate, sustainable fuel source, like nuclear power, the problem of air pollution can be brought to check. Second, utilizing existing steam plant infrastructure reduces initial investment costs and allows investors to keep the existing steam plant running until the new infrastructure is ready to go online.The focus of this research is to design and analyze the topping cycle required to support an existing 300 MW power plant based on the …

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Quantifying Air Flow Rate Through A Server In An Operational Data Center And Assessing The Impact Of Using Theoretical Fan Curve, Neha Shigrekar Jan 2015

Quantifying Air Flow Rate Through A Server In An Operational Data Center And Assessing The Impact Of Using Theoretical Fan Curve, Neha Shigrekar

Mechanical and Aerospace Engineering Theses - Archive

Cooling is one of the major cost factors in data centres that accounts for 37% of the total data centre electricity consumption. Demands on cooling systems have increased substantially in recent years, due to increasing server densities. To avoid the overheating of servers, cooling aisles are over provisioned, but little attention is paid to the actual scenario at the server level. Cooling requirements of the servers is calculated on the basis of fan manufacturer’s published data for the air flow capacity of the server fan and system impedance data obtained from the server designer put together. Thus, the air flow …

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