Experimental Study On The Effects Of Gaseous Contamination On It Equipment,
2013
University of Texas at Arlington
Experimental Study On The Effects Of Gaseous Contamination On It Equipment, Rahul Srinivas Raghunathan
Mechanical and Aerospace Engineering Theses - Archive
Every company is trying to reduce their carbon footprint in today's world. The data center industry is no different. To reduce the cooling costs and increase the efficiency, air -side economizers are used. Air-side economizers bring in outside ambient cold air to cool the data center equipment. Through this, we can save on cooling costs. The problem relating to air-side economization is that we have no control over the humidity and contamination. Humidity and contamination go hand in hand, as one influence the other. In the past filters have been used to combat contamination but it has proved to be …
Development Of Foil Thrust Bearing Test Rig,
2013
University of Texas at Arlington
Development Of Foil Thrust Bearing Test Rig, Rohit Harishchandra Yadav
Mechanical and Aerospace Engineering Theses - Archive
Oil lubricated bearings have been widely used in variety of turbo machinery, though it has its own limitations such as thermal degradation of oil over temperature, complicated oil lubrication system and their maintenance. Commercial application of the air foil bearing (AFB) in Microturbomachinery have been acknowledged. Microturbomachinery term is used in applications with shaft power less than 1000KW and shaft diameter less than 100mm. Microturbomachinery has demanded light weighted, compact, extreme temperature and high speed operation. DN number for oil lubricated bearings and rolling element bearings is very less when compared to foil bearings. Absence of external pressurizing and lubricating …
Point Measurement Of Detonation Wave Propagation Using Ion Guage,
2013
University of Texas at Arlington
Point Measurement Of Detonation Wave Propagation Using Ion Guage, Nitesh Karpakala Manjunatha Gupta
Mechanical and Aerospace Engineering Theses - Archive
Accurate measurement of detonation wave velocity is important in the study of detonations. Detonation wave velocity is calculated by the ratio of distance between two transducers which the wave front travels over the propagation time. Conventional methods included transducers placed a few cm apart thereby yielding an average velocity of the wave. A gauge was developed in which the transducers were placed a few mm apart so that an effective point measurement of velocity can be determined. Different types of sensors used in determining the detonation wave velocity included pressure, flame and ion. Of the three, the ion sensor was …
Effect Of Nanoparticle Dispersions In A Binary Nitrate Salt As Thermal Energy Storage Material In Concentrated Solar Power Applications,
2013
University of Texas at Arlington
Effect Of Nanoparticle Dispersions In A Binary Nitrate Salt As Thermal Energy Storage Material In Concentrated Solar Power Applications, Bharath Dudda
Mechanical and Aerospace Engineering Theses - Archive
Despite the huge improvements in the field of solar energy to produce electricity, the high cost of production has been one of the major problems in this field. Concentrated solar power (CSP) uses a number of mirrors to concentrate solar radiant energy onto a single focal point. Electrical power is produced when the concentrated light is converted to heat, which drives a heat engine connected to an electrical power generator. This heat is first stored in a thermal energy storage (TES) and transferred to a heat engine to be converted to electricity and thus TES can provide heat even after …
Utilization Of Molten Nitrate Salt Nanomaterials For Heat Capacity Enhancement In Solar Power Applications,
2013
University of Texas at Arlington
Utilization Of Molten Nitrate Salt Nanomaterials For Heat Capacity Enhancement In Solar Power Applications, Ramaprasath Devaradjane
Mechanical and Aerospace Engineering Theses - Archive
Concentrated solar power (CSP) system use general thermodynamic cycle to produce electricity and thus the system efficiency is mainly determined by the working temperature of heat transfer fluid (HTF). Organic-based HTFs (e.g., mineral oil, ethylene glycol, etc.) were firstly used for this application. However, this has limited the working temperature of CSP around 300 °C since these organic material starts to decompose below 400 °C. Typical liquid salts are thermally stable to high temperatures (500~600 °C). Using these salts as HTF can significantly increase the working temperature and as a result the system efficiency can also be highly enhanced. For …
Design And Analysis Of A Compression Molded Carbon Composite Wheel Center,
2013
University of Texas at Arlington
Design And Analysis Of A Compression Molded Carbon Composite Wheel Center, Vinoth Kumar Dhananjayan
Mechanical and Aerospace Engineering Theses - Archive
Importance of closed mold and short fibers in the manufacture of carbon composite parts was realized based on a study of existing manufacturing processes for thermoset resins as these can improve production volumes, cost reduction of the part, production of near net shape parts eliminating secondary operations and production of parts with near isotropic properties due to random fiber orientation. Compression molding process is the most preferred process as this addresses the problems of fiber damage effectively because of the minimal flow in the material. A brief study was done on the compression molded carbon composite parts in the industry. …
Integrated Modeling Approach For Solid Oxide Fuel Cell-Based Power Generating System,
2013
University of Texas at Arlington
Integrated Modeling Approach For Solid Oxide Fuel Cell-Based Power Generating System, Jeongpill Ki
Mechanical and Aerospace Engineering Dissertations - Archive
Solid oxide fuel cell (SOFC) systems have been recognized as the most advanced power generation system with the highest thermal efficiency with a compatibility with a wide variety of hydrocarbon fuels, synthetic gas from coal, hydrogen, etc. As a result of research focused on numerical studies for a tubular type- or a planar type-SOFC, fuel flexibility, design aspects of SOFC, materials, start-up process, and so on, SOFC technologies are remarkably being developed.Currently, most research activities are limited to a component level characterization of single fuel cell stack or material research for catalyst, electrolyte, sealing process, etc. In other words, approaches …
Development Of Computational Fluid Dynamics (Cfd) Based Erosion Models For Oil And Gas Industry Applications,
2013
University of Texas at Arlington
Development Of Computational Fluid Dynamics (Cfd) Based Erosion Models For Oil And Gas Industry Applications, Deval Pandya
Mechanical and Aerospace Engineering Dissertations - Archive
Erosion prediction plays a critical role in different oil and gas industry segments including drill bit manufacturing, measurement & logging while drilling (M&LWD), and reservoir engineering/completions tools. Recently, Computational Fluid Dynamics (CFD) is used to predict erosion due to multiphase flows in complex geometries. Currently used CFD-based erosion models are able to predict erosion regions fairly accurately in various applications but they are highly inaccurate when it comes topredictions of quantities like erosion rate. Predicted quantities within an order of magnitude of the measured values are common and may be considered acceptable for many applications in the industry simply because …
Advanced Materials Characterization Based On Full Field Deformation Measurements,
2013
University of Texas at Arlington
Advanced Materials Characterization Based On Full Field Deformation Measurements, A Paige Carpentier
Mechanical and Aerospace Engineering Dissertations - Archive
Accurate stress-strain constitutive properties are essential for understanding the complex deformation and failure mechanisms for materials with highly anisotropic mechanical properties. Among such materials, glass-fiber- and carbon-fiber-reinforced polymer-matrix composites play a critical role in advanced structural designs. The large number of different methods and specimen types currently required to generate three-dimensional allowables for structural design slows down the material characterization. Also, some of the material constitutive properties are never measured due to the prohibitive cost of the specimens needed. This work shows that simple short-beam shear (SBS) specimens are well-suited for measurement of multiple constitutive properties for composite materials and …
Multi-Objective Design Optimization Of Beol/Fbeol Region During Chip Attachment To Substrate,
2013
University of Texas at Arlington
Multi-Objective Design Optimization Of Beol/Fbeol Region During Chip Attachment To Substrate, Hardik Parekh
Mechanical and Aerospace Engineering Theses - Archive
Semiconductor industry has recognized the need to replace traditional Al/SiO2 interconnects with Cu/Low-k interconnects in the mainstream electronics devices following the latter's impact on power, RC delay, and cross-talk reduction. However due to lower elastic modulus, strength, and poor adhesion characteristic, reliability of the Cu/Low-k interconnects turns out to be a concern for its integration in the back-end-of-line (BEoL). Flip-chip attachment process (cooling from ~200C to room) can result in critical damage in nano-scale Cu/Low-k interconnects. The objective of this study is to improve the reliability of Cu/Low-k interconnects during die attach reflow process for a specific die to substrate …
Design And Control Of A Smart Bed For Pressure Ulcer Prevention,
2013
University of Texas at Arlington
Design And Control Of A Smart Bed For Pressure Ulcer Prevention, Zachary Govier Brush
Mechanical and Aerospace Engineering Theses - Archive
This work details the design, simulation, and experimental testing of a mechanically actuated smart hospital bed for the prevention of pressure ulcers in hospital patients. The smart hospital bed, or Smartbed, is designed to improve the “turning” process currently performed by health care workers, ensuring that patients are turned consistently and decreasing the labor requirement for caregivers. The mechanical structure of the bed is described, along with its advantages over current Smartbed products. Next, dynamic models of the Smartbed actuating systems are discussed along with descriptions of the devised single-unit and overall bed control systems. The control equations determined in …
Design And Evaluation Of A Chemical Reactor For The Pyrolysis Wood Pellets,
2013
University of Texas at Arlington
Design And Evaluation Of A Chemical Reactor For The Pyrolysis Wood Pellets, Pawarat Bootpakdeetam
Mechanical and Aerospace Engineering Theses - Archive
Currently there is interest in converting waste biomass into valuable products, such as fuels and specialty chemicals. However, the product composition, yield, the energy required to run the reaction, and the required residence time are all factors influence the economics of the process. Estimate of these factors at the laboratory scale is important for evaluating whether a pilot or demonstration scale study is warranted. In this work, a bench-scale chemical reactor was designed and constructed to conduct the batch pyrolysis of pelletized biomass. The reactor was tested using pine wood pellets as the feedstock. The feedstock weight to reactor volume …
Optimal Design Of Beams,
2013
University of Texas at Arlington
Optimal Design Of Beams, Shivakumar Samala
Mechanical and Aerospace Engineering Theses - Archive
Beams are basic structural components that are capable of withstanding load primarily by resisting bending. Unlike Euler-Bernoulli beams, Timoshenko beams undergo both shear deformation and rotational effects, making it suitable for analyzing the behavior of thick or short beams, composite beams and beams that are subjected to high frequency excitation when their wave length becomes shorter. This thesis work focuses on optimal design of straight and tapered Timoshenko beams under static and dynamic constraints for rectangular and circular cross sections. In this work Timoshenko beam static and dynamic equations were studied. The finite element method was used for static and …
Study Of The Capabilities Of Electrowetting On Dielectric Digital Microfluidics (Ewod Dmf) Towards The High Efficient Thin-Film Evaporative Cooling Platform,
2013
University of Texas at Arlington
Study Of The Capabilities Of Electrowetting On Dielectric Digital Microfluidics (Ewod Dmf) Towards The High Efficient Thin-Film Evaporative Cooling Platform, Jagath B. Yaddessalage
Mechanical and Aerospace Engineering Dissertations - Archive
With the current technological advancement, the size of the electronic components is being reduced to smaller and compact sizes. In the meantime, the packaging density and power consumption is ever increasing. To tackle this challenge, an efficient cooling technology is required.Thin-film evaporation is a very efficient cooling technology. A practical application using thin-film evaporation is a spray cooling which is known as the cooling method that can handle very high heat flux. However, a random spray of coolant cannot guarantee a thin coolant film, therefore either local dry-out or flooding may occur, which hampers cooling efficiency significantly. Moreover, bulky spraying …
Airdata Sensor Based Position Estimation And Fault Diagnosis In Aerial Refueling,
2013
University of Texas at Arlington
Airdata Sensor Based Position Estimation And Fault Diagnosis In Aerial Refueling, Hakki Erhan Sevil
Mechanical and Aerospace Engineering Dissertations - Archive
Aerial refueling is the process of transferring fuel from one aircraft (the tanker) to another (the receiver) during flight. In aerial refueling operations, the receiver aircraft is exposed to nonuniform wind field induced by tanker aircraft, and this nonuniform wind field leads to differences in readings of airdata sensors placed at different locations on the receiver aircraft. There are advantages and disadvantages of this phenomenon. As an advantage, it is used as a mechanism to estimate relative position of the receiver aircraft inside the nonuniform wind field behind the tanker. Using the difference in the measurements from multiple identical sensors, …
A Semi-Analytical Approach To Obtain Physical Fields In Heterogeneous Materials,
2013
University of Texas at Arlington
A Semi-Analytical Approach To Obtain Physical Fields In Heterogeneous Materials, Thanuuj S. Pathapallli
Mechanical and Aerospace Engineering Dissertations - Archive
Predicting the macroscopic response of heterogeneous materials has been the subject of extensive research in the engineering community, even more so, in the composites guild. With analytical solutions being almost impossible to obtain for such open ended problems, and numerical techniques being computationally expensive, semi-analytical methods are highly sought after. This dissertation is one such effort aimed at presenting a semi-analytical approach that serves as a confluence of effective analytical and numerical techniques, to solve for engineering fields in a heterogeneous material characterized by inclusions embedded in a matrix medium. The approach essentially involves the analytical derivation of permissible functions, …
Thermo-Mechanical Analysis Of Nano-Imprint Lithography,
2013
University of Texas at Arlington
Thermo-Mechanical Analysis Of Nano-Imprint Lithography, Bhavik C. Patel
Mechanical and Aerospace Engineering Theses - Archive
Nanoimprint Lithography is being explored by the semiconductor industries for future high volume fabrication of silicon chips, memory devices and patterned media. Nanolithography and Microlithography has played pivotal role in the field of manufacturing microchips and integrated circuits in semiconductor devices. There is an urge to investigate Nanoimprint lithography, a high-throughput, low-cost and nonconventional lithographic method. Thermal management is a critical area that is necessary to be administrated. As recent advancements are being observed in the field of electronic packaging for thermal optimization, likewise steps are also important in this fabrication process. This process involves a heat that is generated …
Compressibility Effects On The Non-Linear Receptivity Of Boundary Layers To Dielectric Barrier Discharges,
2013
University of Texas at Arlington
Compressibility Effects On The Non-Linear Receptivity Of Boundary Layers To Dielectric Barrier Discharges, Marie F.C. Denison
Mechanical and Aerospace Engineering Theses - Archive
The reduction of drag and aerodynamic heating caused by boundary layer transition is of central interest for the development of hypersonic vehicles. Receptivity to flow perturbation in the form of Tollmien-Schlichting (TS) wave growth often determines the first stage of the transition process, which can be delayed by depositing specific excitations into the boundary layer. Weakly ionized Dielectric Barrier Discharge (DBD) actuators are being investigated as possible sources of such excitations, but little is known today about their interaction with high-speed flows. In this framework, the first part of the thesis is dedicated to a receptivity study of laminar compressible …
Rotordynamic Performance Of A Rotor Supported By Three Pad Hybird Foil Bearings With Controlled Air Injection,
2013
University of Texas at Arlington
Rotordynamic Performance Of A Rotor Supported By Three Pad Hybird Foil Bearings With Controlled Air Injection, Sandesh Gudemane
Mechanical and Aerospace Engineering Theses - Archive
Air Foil Bearings have found their place in the commercial applications of turbo machinery. They are cleaner and more reliable at high speeds than their conventional counterparts (Rolling Element Bearings). Low drag friction and apparently no contact during the operation results in a better service life and superior rotor-dynamic performance of the air foil bearings (AFBs). With these advantages AFB has proved to be a suitable option for oil-free turbo-machinery. Further development in AFBs suggest that pressurizing these bearings externally results in remarkably better load carrying capacity, heat dissipation and a more stable rotor. These externally air pressurized bearings which …
Improving Cooling Efficiency Of Servers By Replacing Smaller Chassis Enclosed Fans With Larger Rack-Mount Fans,
2013
University of Texas at Arlington
Improving Cooling Efficiency Of Servers By Replacing Smaller Chassis Enclosed Fans With Larger Rack-Mount Fans, Bharath Nagendran
Mechanical and Aerospace Engineering Theses - Archive
As a common practice in the data center industry, chassis fans are used to direct air flow independent from neighboring servers. However, these fans are less efficient compared to larger rack level counterparts and also operate at higher sound levels. In this study, a novel approach is proposed whereby the smaller chassis enclosed fans are replaced with an array of larger fans, installed behind the stacked servers that share air flow. As a baseline study for comparison of the current scenario, a CPU dominated 1.5U Open Compute server, with four 60mm fans installed within the server, is characterized experimentally for …
