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Articles 2191 - 2220 of 2904

Full-Text Articles in Engineering

Alternative Cooling Technologies For Telecommunication Data Centers: Air Cooling And Rear Door Heat Exchangers, Venkata Naga Poornima Mynampati Jan 2010

Alternative Cooling Technologies For Telecommunication Data Centers: Air Cooling And Rear Door Heat Exchangers, Venkata Naga Poornima Mynampati

Mechanical and Aerospace Engineering Theses - Archive

Telecommunication industry is currently emphasizing to a miniaturization and convergence. The need for smaller, smarter and faster devices is leading drastic increment in power density and accordingly, thermal management of such devices has become a challenge. The heat generated by the devices has to be dissipated in order to ensure proper and efficient functioning of the electronics. Electronics cooling ranges from device level to the room level cooling. Data Center is a facility (room) consisting of servers used for managing and transferring data or information. The thermal management of this facility is challenging due to the huge decrease in floor …

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Adaptive Pain Management Decision Support System, Ching-Feng Lin Jan 2010

Adaptive Pain Management Decision Support System, Ching-Feng Lin

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Pain management is an international health issue. The Eugene McDermott Center for Pain Management at the University of Texas Southwestern MedicalCenter at Dallas conducts a two-stage interdisciplinary pain management program that considers a wide variety of treatments. Prior to treatment (stage 1), an evaluation records the patient's pain characteristics, medical history and related health parameters. A treatment regime is then determined. At the midpoint of their program (stage 2), an evaluation is conducted to determine if an adjustment in the treatment should be made. A final evaluation is conducted at the end of the program to assess final outcomes. The …

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Position Sensorless Control Of A Magnetically Levitated (Maglev) System, Esteban Ricardo Noboa Jan 2010

Position Sensorless Control Of A Magnetically Levitated (Maglev) System, Esteban Ricardo Noboa

Electrical Engineering Dissertations - Archive

The main focus of this investigation is the development and implementation of a sensorless position estimation method and hysteresis position controller for a laboratory-based Maglev system. The proposed estimation method and controller are first validated through modeling and simulation. This sensorless scheme makes use of the maglev system's magnetic signature, namely, its inductance and requires only active phase current measurements. These measurements are then used along with the phase voltage equation to estimate position information that is in a one-to-one correspondence with the system's inductance. The theoretical aspects of the sensorless scheme are described. Finite element analysis (FEA) as well …

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Corporate Environmental Performance Rating Methodology, Arunapprakasini Sankaranarayanan Jan 2010

Corporate Environmental Performance Rating Methodology, Arunapprakasini Sankaranarayanan

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Environmental issues are becoming increasingly important to all kinds of stakeholders and companies themselves, not only for cost avoidance due to regulations, laws, cleanup costs, litigations, controversies, etc, but to improve their intrinsic ethical worth as a company for better environmental sustainability. Off late, companies are increasingly investing in environmental initiatives for cost savings and to generate profits as well. However, since no clear definition of greenness exists, companies are finding it difficult to measure environmental performance as an internal and external benchmark and hence a sound performance measurement system with formal guidelines is yet to be in place. What …

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Fault Detection And Optimal Treatment Of The Permanent Magnet Synchronous Machine Using Field Reconstruction Method, Amir Khoobroo Jan 2010

Fault Detection And Optimal Treatment Of The Permanent Magnet Synchronous Machine Using Field Reconstruction Method, Amir Khoobroo

Electrical Engineering Dissertations - Archive

Permanent magnet synchronous machines (PMSM) are used extensively in industrial applications due to their relatively high power density, high efficiency, negligible rotor losses, maintenance free operation, and ease of control. Fault tolerance has become a design criterion for adjustable speed motor drives (ASMD) which are used in high impact applications. In simple terms, a fault tolerant ASMD is expected to continue its intended function in the event of a failure compliment to its remaining components. A wide variety of the research has been done on the techniques of fault detection. Most of these researches focus solely on the fault detection …

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Development Of Su-8 And Pdms Miniatured Boats And Flotillas, Hao Li Jan 2010

Development Of Su-8 And Pdms Miniatured Boats And Flotillas, Hao Li

Electrical Engineering Dissertations - Archive

In this work, we developed miniaturized SU-8 and PDMS miniaturized boats and flotillas, and explored their designs, fabrication, actuation, motions and driving mechanisms. Like large-scale boats and flotillas, these miniaturized boat and flotillas can be potentially applied to transport designed targets to desired locations in small fluidic systems. They may also be employed as mixers, rotators and so on. We first develop a SU-8 boat, and studied its design, fabrication, actuation and motions. In three types of tests conducted on water free surfaces of different heights in a 30-cm-long channel, the microboat had a speed in the order of 0.1 …

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Light Trapping And Absorption Enhancement For High Performance Solar Cells And Infrared Photodetectors, Li Chen Jan 2010

Light Trapping And Absorption Enhancement For High Performance Solar Cells And Infrared Photodetectors, Li Chen

Electrical Engineering Dissertations - Archive

This dissertation presents the work on light trapping and absorption enhancement in solar cells and infrared photodetectors. Hemispherical microstructure based omni-directional anti reflection (Omni-AR) coating has been designed and developed for solar cells, based on rigorous coupled-wave analysis (RCWA) and convective coating process. Omni-AR coating enhances light absorption in solar cells, due to the reduced reflection on the structured solar cell surfaces, and the increased optical path length (OPL) inside the solar cells. Omni-AR coating has been demonstrated as a cost-effective light trapping approach for different material systems, with very low reflection and high transmission over a large range of …

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Real Time Condition Monitoring Of Chemical Batteries, Anahita Banaei Jan 2010

Real Time Condition Monitoring Of Chemical Batteries, Anahita Banaei

Electrical Engineering Dissertations - Archive

Li-Ion batteries are suitable rechargeable choices for electric and hybrid electric vehicle (EV/HEV) applications due to their relatively high level of energy and power density. One of the important issues in automotive batteries is to monitor their online state-of-charge (SOC) and state-of-health (SOH).Hence, development of an efficient method for monitoring their online state-of-charge (SOC) and state-of-health (SOH) is of high importance for vehicular applications. Open circuit voltage, as one parameter used for predicting the SOC of the battery, is not readily available during charge and discharge cycles. A wide variety of research has been done on SOC and SOH estimation …

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Multi-Wavelength All-Optical 2r Regeneration, Pallavi Govind Patki Jan 2010

Multi-Wavelength All-Optical 2r Regeneration, Pallavi Govind Patki

Electrical Engineering Dissertations - Archive

We experimentally demonstrate, for the first time to our knowledge, simultaneous all-optical 2R regeneration of multiple WDM channels. In the recent work [1], our group has proposed an all-optical 2R regeneration scheme capable of handling multiple WDM channels simultaneously. Our proposed multi-channel regenerator is a modified configuration of Mamyshev's 2R regenerator [2], in which a conventional highly-nonlinear-fiber (HNLF) is replaced by a novel dispersion-managed nonlinear medium. The proposed multi-channel regeneration scheme uses multiple concatenated dispersion-managed sections, where each dispersion-managed section contains a piece of HNLF and a periodic-group-delay device (PGDD). For the proof-of-principle demonstration of the regenerator we have built …

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Adaptive Methods For Realistic And Intuitive Human-Robot Interaction, Jartuwat Rajruangrabin Jan 2010

Adaptive Methods For Realistic And Intuitive Human-Robot Interaction, Jartuwat Rajruangrabin

Electrical Engineering Dissertations - Archive

Due to the advancement in robotics and computer technology, having access to sophisticated robot hardware is becoming common. An increase in the number of robots allows one to achieve different kind of tasks by exploiting cooperation, such as: robot swarms, object manipulation using multiple degrees of freedom of different robots. It is quite challenging for the human operator to coordinate multiple robots to achieve a task in an efficient manner. The channels available to receive feedback information from the robot system can vary from simple encoder reading to video stream acquisition of the robot system performing tasks. It is important …

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Photonic Crystal Cavities For Spectrally-Selective Optoelectronic Devices, Hongjun Yang Jan 2010

Photonic Crystal Cavities For Spectrally-Selective Optoelectronic Devices, Hongjun Yang

Electrical Engineering Dissertations - Archive

Photonic crystal (PC) structures exhibit unconventional dispersion and refractive properties making possible hitherto not realizable optical and optoelectronic devices with high spectral selectivity. Functional PC devices (e.g., optical filters, reflectors, and photo detectors and light emitters) on both Si and III-V semiconductor material systems were fabricated via E-Beam lithography (EBL). The device layer can be further transferred onto foreign substrates such as glass or plastic (PET), using a low-cost "wet nanomembrane transfer technique" developed in this study.The broadband membrane reflectors (MR) based on Fano resonances in patterned silicon nanomembranes have been demonstrated. Resonance control of the reflectors was realized either …

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Neuro Adaptive Control For Aerospace And Distributed Systems, Abhijit Das Jan 2010

Neuro Adaptive Control For Aerospace And Distributed Systems, Abhijit Das

Electrical Engineering Dissertations - Archive

Nonlinear and adaptive control is generally considered one of the most effective techniques for stabilizing complex nonlinear systems, where linear control techniques may fail completely. Thousands of research papers are published on either theory or applications of nonlinear and adaptive control. But often one obvious question arises how to implement these techniques in real life model? The best answer that one can think of is to develop simple nonlinear control laws which are easy to implement. Moreover for controlling multi-agent systems, it is often required to distribute the control laws based on limited information available among the agents. This research …

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Wavelet Based Array Comparative Genomic Hybridization And Mass Spectrometry Data Analysis, Nha Nguyen Jan 2010

Wavelet Based Array Comparative Genomic Hybridization And Mass Spectrometry Data Analysis, Nha Nguyen

Electrical Engineering Dissertations - Archive

As a highly efficient technique, array-based comparative genomic hybridization (aCGH) methods allow the simultaneous measurement of genomic DNA copy number at hundreds or thousands of loci and the reliable detection of local one-copy-level variations. The identification of these DNA copy number changes provides insights to facilitate both the basic understanding of cancer and its diagnosis. In order to effectively analyze aCGH data, various techniques have been proposed to help researchers smooth the DNA copy number data and subsequently to quantify the alterations. In this thesis, many wavelet based methods are proposed to smooth and segment the aCGH data that is …

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A Tutorial On Functionality Of Wimax And It's Performace Evaluation, Amay Dhirendra Umradia Jan 2010

A Tutorial On Functionality Of Wimax And It's Performace Evaluation, Amay Dhirendra Umradia

Electrical Engineering Theses - Archive

Recently, there have been tremendous developments on wireless communication technology which have predicted to replace the wirelined system and provide incredible bandwidth to the consumers. The IEEE standard for this technology is known as 802.16e (Mobile WiMAX) which was officially published in the year 2006. WiMAX would provide broadband access to rural and developing countries where the option of DSL, cable and Wi-Fi is unavailable. This Thesis provides a tutorial overview of 802.16. The information for this article is gathered from The Institute of Electrical and Electronics Engineers (IEEE) website, the WiMAX forum website and other resources on the internet. …

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A Planar Cavity Backed Slot Antenna Array For Ultra-Wideband Monopulse Radars, Vinay Magadi Vikram Jan 2010

A Planar Cavity Backed Slot Antenna Array For Ultra-Wideband Monopulse Radars, Vinay Magadi Vikram

Electrical Engineering Theses - Archive

In this thesis, a wideband cavity backed slot antenna is designed for automotive-borne monopulse radar applications. A rectangular slot is used to realize broad bandwidth; the slot is backed by a cavity and vertical walls of the cavity are implemented by discrete vias; and the slot is fed by an inverted microstrip line. The antenna in this letter is compact, robust, fully planar, and easy to integrate. A two-element array is fabricated and tested. Measured input impedance is matched to 50-ohm within band [2.61 GHz, 3.44 GHz] (27.5% bandwidth); and monopulse beam-scanning is successfully demonstrated.

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Dispersion Engineering With Leaky-Mode Resonance Structures, Xin Wang Jan 2010

Dispersion Engineering With Leaky-Mode Resonance Structures, Xin Wang

Electrical Engineering Theses - Archive

In the thesis, a numerical method for the analysis of optical pulses propagation through leaky-mode/guided-mode resonance (GMR) structures is implemented by integrating a Fourier decomposition technique and the rigorous coupled-wave analysis (RCWA) method. Dispersion properties of several GMR structures such as single-grating-layer GMR filters, coupled GMR filters, and cascaded GMR filters are studied and their interaction with optical pulses investigated. For device applications, a high-Q transmission filter is formed by coupling GMR reflection filters which can withstand typical attenuation in silicon. Wavelength division multiplexing (WDM) filters are proposed by cascading a number of GMR transmission filters. Generally, a N channel …

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Development Of Magnetic-Based Core-Shell Nanoparticles For Drug Delivery Applications In Melanoma Skin Cancer, Zarna A. Bhavsar Jan 2010

Development Of Magnetic-Based Core-Shell Nanoparticles For Drug Delivery Applications In Melanoma Skin Cancer, Zarna A. Bhavsar

Bioengineering Theses - Archive

Melanoma skin cancer is the most dangerous form of skin cancer and the major cause of deaths related to skin cancer worldwide. Conventional chemotherapeutic treatment is not very effective and faces many problems such as low response rate, development of multidrug resistance, and severe side effects. In order to address these limitations and improve melanoma treatment efficacy, development of a multifunctional nanoparticulate drug delivery system is desired. Thus, we aimed towards the development of magnetic-based core-shell nanoparticles (MBCS NPs) for dual drug release and dual targeting of melanoma tumors. The synthesized nanoparticles were composed of Poly (Lactic-co-glycolic acid) (PLGA) particle …

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A Novel Injectable Porous Hydrogel Composite Scaffold For Bone Tissue Engineering, Parvathi Nair Jan 2010

A Novel Injectable Porous Hydrogel Composite Scaffold For Bone Tissue Engineering, Parvathi Nair

Bioengineering Theses - Archive

Over the past decade there has been an increasing use of bone grafts for orthopedic applications. With the aging US population, the need for suitable bone grafts substitutes has also increased. The aim of this study was to develop a novel in situ crosslinkable hydrogel composite for tissue-engineering critical-sized bone defects. This system consists of a newly developed water-soluble biodegradable hydrogel Poly ((ethylene glycol) maleate citrate) (PEGMC) and hydroxyapatite (HA). The PEGMC/HA system is completely injectable and can be crosslinked in situ into crosslinked PEGMC/HA (CPEGMC/HA) hydrogel composite with or without poly (ethylene glycol) diacrylate (PEGDA) as a crosslinker. The …

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Microfluidic Systems For Studying Cell Motility, Srikanth Vasudevan Jan 2010

Microfluidic Systems For Studying Cell Motility, Srikanth Vasudevan

Bioengineering Theses - Archive

It is very imperative to develop new in vitro platforms that can help in studying the complex interactions that occur between cell-Extracellular Matrix proteins and also during the process of cell migration in vivo. Such tools would facilitate in better understanding of the mechanisms that are employed by the cells during growth and migration. There are two devices that are presented in this study; 1) Multi-biomolecule coated lane device for unbiased cell preferential migration and 2) Novel Microchannel device for real time monitoring of tumor cell migration.The Multi-biomolecule coated lane device is a basic in vitro platform that helps in …

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Environmentally-Conscious Supply Chain Design In Support Of Food Security, Caroline C. Krejci, Benita M. Beamon Jan 2010

Environmentally-Conscious Supply Chain Design In Support Of Food Security, Caroline C. Krejci, Benita M. Beamon

Industrial, Manufacturing, and Systems Engineering Faculty Publications - Archive

This paper seeks to design food supply chain structures that can provide food security for every person in the world while supporting long-term environmental sustainability. In particular, we provide alternatives to the current food supply chain structure and analyze their potential for providing food security, in terms of productive capacity and long-term environmental sustainability. Given the current world population and expected continued growth, our analysis suggests that environmentally-sustainable food supply chains would be most effectively supported by local and organic agriculture, while maintaining a parallel industrial agricultural system. This hybrid system would adopt environmentally-sustainable principles whenever possible, seeking to increase …

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Development Of An Optical Fiber-Based Corrosion Detection Sensor Based On Laser Light Reflection, Manjunatha Shenoy Jan 2010

Development Of An Optical Fiber-Based Corrosion Detection Sensor Based On Laser Light Reflection, Manjunatha Shenoy

Mechanical and Aerospace Engineering Theses - Archive

Corrosion plays a detrimental effect on the structural integrity of many engineering structures. It can compromise the safe operation of these structures by forming corrosion pits that deteriorates the structural surfaces and causes stress concentrations. Therefore, it is critical that corrosions are detected before structural integrity is compromised and repair becomes economically prohibitive. However, corrosions usually occur at intricate places that are hard to inspect visually. Manual inspection of the structures for corrosions requires dismantling the structures, which incurs high maintenance costs and could potentially cause damage to the components. One approach to reduce this cost is to detect and …

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An Integration Of A Modern Flight Control System Design Technique Into A Conceptual Design Stability And Controls Tool, Aeromech, Amen Omoragbon Jan 2010

An Integration Of A Modern Flight Control System Design Technique Into A Conceptual Design Stability And Controls Tool, Aeromech, Amen Omoragbon

Mechanical and Aerospace Engineering Theses - Archive

The aircraft conceptual design (CD) phase is the most abstract, thus challenging phase of the entire aircraft design process. It is the responsibility of the CD engineer to identify and then to explore various aircraft concepts with the goal of arriving at the most promising concept for further evaluation. During this early design phase, the discipline stability and control tends to be underrepresented due to the lack of non-linear aerodynamic and inertia data. The methodology and software AeroMech is a vehicle configuration independent aircraft conceptual design stability and control tool, developed to help the conceptual designer to address stability and …

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Alternative Matching Schemes For Automatic Fingerprint Identification Systems, Michael Jason Futer Jan 2010

Alternative Matching Schemes For Automatic Fingerprint Identification Systems, Michael Jason Futer

Electrical Engineering Theses - Archive

Biometrics is a recognition technology that uses the unique behavioral and physiological traits of the human body as identifiers. The fingerprint is one of the oldest and most widely used forms of biometric identifiers. In this thesis, an automatic fingerprint identification system designed by a previous Electrical Engineering graduate student at The University of Texas at Arlington is upgraded with the purpose of improving matching accuracy. A review of the baseline automatic fingerprint identification system is provided as a reference point for improvements in the system. Then, improvements to the image enhancement stage of the baseline system are discussed. They …

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A Ph Sensor Based On A Flexible Substrate, Wen-Ding Huang Jan 2010

A Ph Sensor Based On A Flexible Substrate, Wen-Ding Huang

Electrical Engineering Dissertations - Archive

pH sensor is an essential component used in many chemical, food, and bio-material industries. Conventional glass electrodes have been used to construct pH sensors, however, have some disadvantages. Glass electrodes are easily affected by alkaline or HF solution, they require a high input impedance pH meter, they often exhibit a sluggish response. In some specific applications, it is also difficult to use glass electrodes for in vivo biomedical or food monitoring applications due to the difficulty of size miniaturization, planarization and polymerization based on current manufacturing technologies. In this work, we have demonstrated a novel flexible pH sensor based on …

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Distribution Network Contingency Analysis And Contingency Detection With The Consideration Of Load Models, Qiaohui Hu Jan 2010

Distribution Network Contingency Analysis And Contingency Detection With The Consideration Of Load Models, Qiaohui Hu

Electrical Engineering Dissertations - Archive

The electric utility market environment has changed quite radically during recent years due to the process of deregulation. This has changed the asset management towards a capital controlled business where owners are trying to maximize their profits with cost optimization. To keep up with the increase demands on high reliability and high quality delivery systems, many utilities endeavor to rationalize their system operations with more intelligent control schemes and facilities. A lot of issues under uncertainty such as load growth, quality of supply and environmental impact affect the reliability of the distribution system. Power outage is the most serious challenge …

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Imbalance Response Of A Four Degree Of Freedom Rigid Rotor Supported By Hybrid Three Pad Air Foil Bearing, Prajwal Krishna Shetty Jan 2010

Imbalance Response Of A Four Degree Of Freedom Rigid Rotor Supported By Hybrid Three Pad Air Foil Bearing, Prajwal Krishna Shetty

Mechanical and Aerospace Engineering Theses - Archive

Air foil bearings (AFB's) are widely used in small to midsized turbomachinery. They provide safer, cleaner and cheaper bearing operation. They are simple in construction, offer very low drag friction and have very high reliability at high speed operations. A major advantage of air foil bearings compared to conventional rigid surface bearings is their superior dynamic performance in rotor bearing systems. Since there is no contact between the rotor and bearing surface, the air foil bearings have a higher service life compared to rigid surface bearings. Hybrid AFB's operate under both hydrodynamic and hydrostatic condition. The present study is a …

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Evaluation Of Trenchless Renewal Methods For Potable Water Distribution Pipes, Abhay A. Jain Jan 2010

Evaluation Of Trenchless Renewal Methods For Potable Water Distribution Pipes, Abhay A. Jain

Civil Engineering Theses - Archive

Undoubtedly, potable water pipes, as part of an underground infrastructure system, play a key role in maintaining quality of life, health and well being of human kind. As these potable water pipes reach the end of their useful life, they create high maintenance costs, loss of flow capacity, decreased water quality, and increased dissatisfaction. Trenchless renewal methods (TRMs) are a medium to renew deteriorated potable water pipes, thus decreasing leakage loss, emergency maintenance costs and customer complaints. TRMs also maintain the quality of the water leaving the treatment plant. America's drinking water systems faces an annual shortfall of at least …

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An Investigation Of Productivity Loss Due To Outdoor Noise Conditions, Shripad Dilip Maldikar Jan 2010

An Investigation Of Productivity Loss Due To Outdoor Noise Conditions, Shripad Dilip Maldikar

Civil Engineering Theses - Archive

Most people in day to day life at one time or other get irritated or distracted by surrounding noises. The irritation might have resulted in minor aggravation or may have been dramatic enough to hinder their work. This leads us to think whether there are any losses in the efficiency of construction workers due to surrounding varying noise conditions, or if they naturally adjust to their acoustic environment. In an effort to answer this question, this study on productivity loss due to varying sound conditions was conducted. It was found that, the efficiency of laborers was inversely proportional to the …

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A Study On The Corrosion Behavior Of Nanocrystalline Nickel In Aqueous Environments, Anjana Shyam Sundar Jan 2010

A Study On The Corrosion Behavior Of Nanocrystalline Nickel In Aqueous Environments, Anjana Shyam Sundar

Material Science and Engineering Theses - Archive

Nanocrystalline materials possess considerably enhanced properties arising from their small grain size. Significant interest has been paid in the past to their mechanical and physical properties. Very little attention has been attracted by their electrochemical behavior, which is expected to be affected by the significant volume fraction of grain boundaries. In the present study, corrosion experiments were conducted in nanocrystalline nickel in two entirely different solutions in order to obtain a better understanding of its corrosion behavior. This is of particular interest to MEMS and NEMS devices where electroplated nanocrystalline nickel is the metal of choice. The corrosion behavior of …

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Performance-Based Plastic Design Of Earthquake Resistant Steel Structures: Concentrically Braced Frames, Tall Moment Frames, Plate Shear Wall Frames, Mohammad Reza Bayat Jan 2010

Performance-Based Plastic Design Of Earthquake Resistant Steel Structures: Concentrically Braced Frames, Tall Moment Frames, Plate Shear Wall Frames, Mohammad Reza Bayat

Civil Engineering Dissertations - Archive

It is well known that structures designed by current codes experience large inelastic deformations during major earthquakes. However, current seismic design practice in the U.S. is based on elastic structural behavior and accounts for inelastic behavior only in an indirect manner through certain modification factors such as R, I, and Cd. Under moderate to severe earthquakes, inelastic activity, including severe yielding and buckling of structural members can be unevenly distributed in the structure which may result in global collapse or costly repair work. Recently, a new design method has been developed and referred to as Performance-Based Plastic Design (PBPD). This …

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