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Articles 1321 - 1350 of 2904

Full-Text Articles in Engineering

Optimal Operation Of Microgrid Under A Stochastic Environment, Zhaohao Ding Jan 2015

Optimal Operation Of Microgrid Under A Stochastic Environment, Zhaohao Ding

Electrical Engineering Dissertations - Archive

With its technological and regulatory innovation of scale and structure, microgrids have been developed all over the world as a mean to address the high penetration level of renewable generation, reduce the greenhouse gas emission, and provide economical solutions for the currently non-electrified area. The operation of microgrid requires resource planning for those fossil-fuel based generators, energy storage systems, and demand resources if demand side management is implemented. Due to the stochastic nature of renewable energy resources, load behaviors and market prices, enormous uncertainties are involved in the microgrid operation and scheduling problems for both short-term and longer term. These …

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Employing Online Data For Dynamic Equivalent Model Parameter Identification Of Large Scale Wind Farm, Xueyang Cheng Jan 2015

Employing Online Data For Dynamic Equivalent Model Parameter Identification Of Large Scale Wind Farm, Xueyang Cheng

Electrical Engineering Dissertations - Archive

As one of the major renewable energy sources, wind power has experienced a fast growth in recent years. The installed capacity of wind farms has increased dramatically. Similar to other generator facilities, their impacts on power system transient stability and power quality should be carefully studied when large scale wind farms are integrated into the power grid. Therefore, it is necessary to establish an accurate dynamic model of large scale wind farm for researches and engineers. A large scale wind farm may have hundreds of WTGs and the structure of WTGs is very complicated and manufacture dependent. If each machine …

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Electrostatic And Piezoelectric Micro Energy Harvesters For Environmental Vibrational Energy Scavenging, Yi Li Jan 2015

Electrostatic And Piezoelectric Micro Energy Harvesters For Environmental Vibrational Energy Scavenging, Yi Li

Electrical Engineering Dissertations - Archive

Nowadays wireless sensors are widely used in all kinds of fields such as biomedical, commercial and military. Micro energy harvesters converting the wasteful energy from environment into electricity enable the possibility of self-powered wireless sensor systems. This dissertation aims to develop micro energy harvesters to harness wasted mechanical vibrational energy. An electrostatic micro energy scavenger was designed to incorporate MEMS comb-drive in-plane overlap as well as in-plane gap closing topologies into one hybrid structure. The device geometry and dimensions were optimized to maximize the energy harvesting efficiency. UV-LIGA process combined with nickel electroplating was utilized to fabricate the devices. A …

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A Microwave Backscattering Model For Precipitation, Seda Ermis Jan 2015

A Microwave Backscattering Model For Precipitation, Seda Ermis

Electrical Engineering Dissertations - Archive

A geophysical microwave backscattering model for space borne and ground-based remote sensing of precipitation is developed and used to analyze backscattering measurements from rain and snow type precipitation. Vector Radiative Transfer (VRT) equations for a multilayered inhomogeneous medium are applied to the precipitation region for calculation of backscattered intensity. Numerical solution of the VRT equation for multiple layers is provided by the matrix doubling method to take into account close range interactions between particles. In previous studies, the VRT model was used to calculate backscattering from a rain column on a sea surface [41]. In the model, Mie scattering theory …

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Autonomous Robotic Landmine Detection, Mapping And Avoidance, Sandesh Gowda Jan 2015

Autonomous Robotic Landmine Detection, Mapping And Avoidance, Sandesh Gowda

Electrical Engineering Theses - Archive

The objective of this thesis is to develop detection algorithm to can solve socially challenging issue of Landmine mapping & removal. Landmines which used to be a safety measure during wars, play a dangerous role in civilian life, in and around the post combat regions with approximately 78 countries observing an estimate of 42 human lives killed every day. To prevent the number of casualties and manual mine clearance, mobile robots can be used for detection & mapping of the mine field region.Mapping, detection and avoidance are the primary challenges faced on a landmine removal. In this thesis, mine center …

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Hemodynamic Responses To Thermal Stimulation In The Prefrontal Cortex Of The Brain Measured By Fnirs, Koumudi Chari Jan 2015

Hemodynamic Responses To Thermal Stimulation In The Prefrontal Cortex Of The Brain Measured By Fnirs, Koumudi Chari

Bioengineering Theses - Archive

Although FMRI has marked its importance in the neurological research by understanding the brain activities, FNIRS has also set a new standard in the brain imaging study research with non-invasive and easy to use technology. FNIRS is a portable, inexpensive optical imaging method that measures the changes in the oxygenated and de-oxygenated hemoglobin of the brain that results from the neurological activity. In this study, FNIRS has been used to study the pain processing in humans by measuring the pre-frontal cortex area of the brain. Eight (n=8) healthy subjects were induced with pain using a thermal stimulator device with temperatures …

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An Investigation Of The Covariations Between Variations In Exhaled Carbon Dioxide And Cerebral Blood Flow Levels During Apnea, Varun Ajay Kanal Jan 2015

An Investigation Of The Covariations Between Variations In Exhaled Carbon Dioxide And Cerebral Blood Flow Levels During Apnea, Varun Ajay Kanal

Bioengineering Theses - Archive

Sleep apnea is a breathing disorder characterized by repetitive reduction or cessation of breathing during sleep. It is estimated that that around 17% of adults suffer from mild to severe sleep disordered breathing. The aim of this study was to investigate the level of correlation between variations in exhaled CO2 and cerebral blood flow (CBF) during apnea. It is difficult to measure the CBF during sleep. This relationship was found in an effort to substitute the measurement of the changes in CBF with the changes in the CO2. The relationship between these two physiological parameters was first studied in healthy …

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Two-Stage Stochastic Programming In Adaptive Interdisciplinary Pain Management, Na Wang Jan 2015

Two-Stage Stochastic Programming In Adaptive Interdisciplinary Pain Management, Na Wang

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Chronic pain is a global health problem. About 100 million adult Americans suffering from chronic pain, which costs $560 - $635 billion per year. The Eugene McDermott Center for Pain Management at the University of Texas Southwestern Medical Center at Dallas conducted a two-stage pain management program for patients who suffer from chronic pain. Data information such as patient’s parameter, past treatment, pain outcome at different evaluation point and so on has been collected by the McDermott Center. The University of Texas at Arlington is collaborating with the McDermott Center to find optimal treatment strategies for individual patients.A treatment strategy …

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High-Dimensional Adaptive Dynamic Programming With Mixed Integer Linear Programming, Zirun Zhang Jan 2015

High-Dimensional Adaptive Dynamic Programming With Mixed Integer Linear Programming, Zirun Zhang

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Dynamic programming (DP, Bellman 1957) is a classic mathematical programming approach to solve multistage decision problems. The “Bellman equation” uses a recursive concept that includes both the current contribution and future contribution in the objective function of an optimization. The method has potential to represent dynamic decision-making systems, but an exact DP solution algorithm is limited to small problems with restrictions, such as problems with linear transitions and problems without uncertainty. Approximate dynamic programming (ADP) is a modern branch of DP that seeks to achieve numerical solutions via approximation. It is can be applied to real-world DP problems, but there …

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Performance Characteristics Of Single Effect Lithium Bromide/ Water Absorption Chiller For Small Data Centers, Abhishek Arun Babu Mysore Jan 2015

Performance Characteristics Of Single Effect Lithium Bromide/ Water Absorption Chiller For Small Data Centers, Abhishek Arun Babu Mysore

Mechanical and Aerospace Engineering Theses - Archive

A medium data center consists of servers performing operations such as file sharing, collaboration and email. There are a large number of small and medium data centers across the world which consume more energy and are less efficient when compared to large data center facilities of companies such as GOOGLE, APPLE and FACEBOOK. Such companies are making their data center facilities more environmental friendly by employing renewable energy solutions such as wind and solar to power the data center or in data center cooling. This not only reduces the carbon footprint significantly but also decreases the costs incurred over a …

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Chip Package Interaction Study To Analyze The Mechanical Integrity Of A 3-D Tsv Package, Pavan Rajmane Jan 2015

Chip Package Interaction Study To Analyze The Mechanical Integrity Of A 3-D Tsv Package, Pavan Rajmane

Mechanical and Aerospace Engineering Theses - Archive

The convergence and miniaturization of computing and communications dictates building up rather than out. As planar device miniaturization continues to its ultimate limits, the complexity of circuit interconnections for 2-D devices becomes a limitation for performance and drives up power dissipation [1]. As the consumers demand more functions on their hand-held electronic devices, the need for more devices such as memory, CPU and GPU in hand-held type footprints is increasing. Chip-stacking (3-D) is emerging as a powerful tool that satiates such IC package requirements. A 3-D FPGA would overcome the interconnect limitations, resulting in greater silicon efficiency per function (number …

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Experimental Study Of Quaternary Nitrate/Nitrite Molten Salt As Advanced Heat Transfer Fluid And Energy Storage Material In Concentrated Solar Power Plant, Sumeet Changla Jan 2015

Experimental Study Of Quaternary Nitrate/Nitrite Molten Salt As Advanced Heat Transfer Fluid And Energy Storage Material In Concentrated Solar Power Plant, Sumeet Changla

Mechanical and Aerospace Engineering Theses - Archive

Solar energy is used to produce electricity by two methods namely photovoltaic and concentrated solar power plant systems. Concentrated Solar power plants hold a distinct advantage over photovoltaic, which is that of energy storage. Energy can be stored in thermal energy storage system during day time and can be used to dispatch energy during peak demand and during raining or cloudy days to produce electricity. All concentrated solar power plants in operation use sensible heat storage method to store energy. Sensible heat storage system have been used in industry owing to ease of dispatch ability. Currently a binary mixture of …

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Impact Of Viscoelastic Material Characterization Of Pcb's On Thermomechanical Properties Of Qfn Thick Package Under Thermal Cycling, Karthik Rajashekar Jan 2015

Impact Of Viscoelastic Material Characterization Of Pcb's On Thermomechanical Properties Of Qfn Thick Package Under Thermal Cycling, Karthik Rajashekar

Mechanical and Aerospace Engineering Theses - Archive

The QFN component package is a quad flat pack (QFP) with “no-leads”, where the electrical contact to the printed circuit board (PCB) is made through soldering of the lands underneath the package body rather than the traditional leads formed along the perimeter. The popularity of this device package style is primarily due to the superior electrical and thermal performance demonstrated. It is one of the most cutting-edge technologies emerged in the market, exhibiting high performance with unparalleled cost effectiveness. But using thick PCBs (>3mm) is detrimental to the package reliability. The motivation of this work is to understand and …

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Liquid Cooling Of A High-Power Multi-Chip Module Using A Sectioned Cold Plate, Ananthavijayan Sridhar Jan 2015

Liquid Cooling Of A High-Power Multi-Chip Module Using A Sectioned Cold Plate, Ananthavijayan Sridhar

Mechanical and Aerospace Engineering Theses - Archive

With the advancement in micro-fabrication techniques and high performance chips, the heat flux generated through these electronics is reaching a point where air-cooling of these devices is not efficient enough. By definition, Multi-Chip Modules (MCMs) are specialized electronic packages where multiple Integrated-Circuits (ICs) and semiconductor dies are unified onto a single substrate. Increasing advancements in ICs enable MCMs as alternate packaging finding its application in high power electronics like power generation and cooling, medical devices, lasers and, military electronics etc. Hence, liquid cooling techniques are explored as possible solutions. In this study, a high power MCM is considered and, its …

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Study Of The Effect Of Ion Concentration, Ph, And Surface Charge On Single-Particle Placement, Kunhua Yu Jan 2015

Study Of The Effect Of Ion Concentration, Ph, And Surface Charge On Single-Particle Placement, Kunhua Yu

Material Science and Engineering Theses - Archive

Supervising Professor: Seong Jin Koh Single particle placement (SPP) in which nanoparticles are placed on exact substrate positions on a single particle level has drawn a lot of attention as it can be used as an effective tool for bottom-up fabrications of nanoscale systems. In SPP, single nanoparticles are electrically guided toward substrate target positions through electrostatic funneling mechanism and once a single nanoparticle is placed on a target position it prevents the other nanoparticles from approaching toward the substrate, leading to placement of exactly one nanoparticle on each target position. This thesis investigates the role of three key parameters …

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Effect Of Termite Gut Microbe Tav5 On Methane Production From Municipal Solid Waste Degradation, Hoda Rahimi Jan 2015

Effect Of Termite Gut Microbe Tav5 On Methane Production From Municipal Solid Waste Degradation, Hoda Rahimi

Civil Engineering Theses - Archive

Methane from anaerobic processes is being increasingly utilized as an alternative energy source in developed countries, via large projects that extract methane from landfills or wastewater treatment plants. Anaerobic degradation of organic material (biomass) involves decomposition by bacteria under humid conditions without any oxygen. Organic carbon deposited in landfills is converted by microbes to carbon dioxide (CO2) and methane (CH4). If the methane is not captured, it contributes to climate change (25 times more effectively than CO2 on a per-mass basis). If the methane is captured, it can be used as a renewable energy resource. Lignocellulose comprises a significant portion …

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A New Technique For The Estimation Of The Elastic Moduli Of Pavement Layers From Light Weight Deflectometer Data, Nickey Akbariyeh Jan 2015

A New Technique For The Estimation Of The Elastic Moduli Of Pavement Layers From Light Weight Deflectometer Data, Nickey Akbariyeh

Civil Engineering Theses - Archive

This study developed a method to estimate the elastic moduli of a flexible pavement system from Light Weight Deflectometer deflection data. The forward method (simple equations) can be easily programmed into the data acquisition device of the Light Weight Deflectometers. The equations can be of a primary assistance in the evaluation of the flexible pavement structures. The method is simple and it eliminates the need for the backcalculation procedure after the LWD test. The pavement systems considered in this study are composed of 2 to 4 inches of the asphalt concrete wearing layer and 4 to 8 inches of compacted …

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Potential Applicability Of Stress Wave Velocity Method On Pavement Base Materials As A Non-Destructive Testing Technique, Masrur Mahedi Jan 2015

Potential Applicability Of Stress Wave Velocity Method On Pavement Base Materials As A Non-Destructive Testing Technique, Masrur Mahedi

Civil Engineering Theses - Archive

Aggregates derived from natural sources have been used traditionally as the pavement base materials. But in recent times, the extraction of these natural aggregates has be-come more labor intensive and costly due to resource depletion and environmental concerns. Thus, the uses of recycled aggregates as the supplementary of natural aggregates are increasing considerably in pavement construction. Use of recycled aggregates such as recycled crushed concrete (RCA) and recycled asphalt pavement (RAP) reduces the rate of natural resource depletion, construction debris and cost. Although recycled aggregates could be used as a viable alternative of conventional base materials, strength characteristics and product …

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Fatigue Life Assessment Of A Critical Field Welded Connection On A Temporary Railway Bridge Span, Curtis Heinsen Jan 2015

Fatigue Life Assessment Of A Critical Field Welded Connection On A Temporary Railway Bridge Span, Curtis Heinsen

Civil Engineering Theses - Archive

There is a need in the railway industry for a flexible solution to the problem of service interruptions due to impacts on railway bridges from highway and other vehicle traffic. One such solution is the placement of a temporary span that can be used on multiple substructure types and configurations and can be quickly assembled from a kit of available parts. In order to minimize the erection time and maximize the span flexibility such a span could utilize welded connections in place of bolted connections throughout the structure. These connections would be vulnerable to fatigue failure which has been shown …

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Factors Influencing The Microbial Calcium Carbonate Precipitation Performance In Sands, Naga Venkata Prasanna Kumar Velpuri Jan 2015

Factors Influencing The Microbial Calcium Carbonate Precipitation Performance In Sands, Naga Venkata Prasanna Kumar Velpuri

Civil Engineering Theses - Archive

Microbial induced calcium carbonate precipitation is relatively a new ground improvement technique for geotechnical engineers. This technique uses non-pathogenic organisms that are found naturally in soil environment to cement sand particles together at their contacts. This thesis describes the influence of various factors on cementation of MICP-treated soil catalyzed by bacteria and urease from an experimental study. Some of these factors include number of nutrient cycles, concentration of calcium chloride solutions, number of injections and particle size. Finally the objective of my research is to have a better understanding about the effects of various parameters on the biological cementation. Ottawa …

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Testing, Analysis And Classification Of No-Dig Manhole Rehabilitation Materials, Alimohammad Entezarmahdi Jan 2015

Testing, Analysis And Classification Of No-Dig Manhole Rehabilitation Materials, Alimohammad Entezarmahdi

Civil Engineering Theses - Archive

Gravity flow wastewater collection systems are comprised of sewer pipes and manholes. Failure of a manhole may have catastrophic consequences such as developing a sinkhole in the street and roadway, and at a minimum, wastewater flow will be blocked and stream of the manhole will backup causing a sanitary sewer overflow (SSO). Improving structural conditions of a manhole is critical to minimize these types of failures. This thesis considers the impact of several lining materials including cement mortar, epoxy, polyurethane, cured-in-place composites, and a multi- layer structure material on increasing the structural capabilities of deteriorated manholes. The tasks included in …

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Development Of The Duplicate Shear Test For Asphalt Mixtures, Mohammadreza Khajeh Hosseini Jan 2015

Development Of The Duplicate Shear Test For Asphalt Mixtures, Mohammadreza Khajeh Hosseini

Civil Engineering Theses - Archive

Permanent shear deformation is the main cause of rutting in asphalt concrete layers. Therefore, the determination of the shear properties of asphalt mixtures is helpful for predicting the rutting in asphalt pavement structures and for the identification of poor performing asphalt mixtures. The objective of this study was to develop a new test device to replicate similar loading conditions and constraints of the Superpave Shear Tester (SST). The new device, named the Double Shear Tester (DST), determines the mechanical average of the shear properties and responses of two specimens instead of that of a single specimen as in the SST …

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Assessing Values-Based Sourcing Strategies In Regional Food Supply Networks: An Agent-Based Approach, Caroline C. Krejci, Michael C. Dorneich, Richard T. Stone Jan 2015

Assessing Values-Based Sourcing Strategies In Regional Food Supply Networks: An Agent-Based Approach, Caroline C. Krejci, Michael C. Dorneich, Richard T. Stone

Industrial, Manufacturing, and Systems Engineering Faculty Publications - Archive

The recent increase in demand for regionally produced food has resulted in a need for more efficient distribution methods. To connect regional food producers and consumers, intermediated regional food supply networks have developed. The intermediary, known as a regional food hub, serves as an aggregation point for products and information. It may also act as a filter to ensure that the requirements of both producers and consumers are consistently met. This paper describes an empirically based agent-based model of a regional food network in central Iowa that is intermediated by a food hub. The model was used to test a …

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Adaptive Multiple Optimal Learning Factors For Neural Network Training, Jeshwanth Challagundla Jan 2015

Adaptive Multiple Optimal Learning Factors For Neural Network Training, Jeshwanth Challagundla

Electrical Engineering Theses - Archive

There is always an ambiguity in deciding the number of learning factors that is really required for training a Multi-Layer Perceptron. This thesis solves this problem by introducing a new method of adaptively changing the number of learning factors computed based on error change created per multiply. A new method is introduced for computing learning factors for weights grouped based on the curvature of the objective function. A method for linearly compressing large ill-conditioned Newton's Hessian matrices to smaller well-conditioned ones is shown. This thesis also shows that the proposed training algorithm adapts itself between two other algorithms in order …

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System Security, Threat Detection And Prevention Measures Of Autonomous Systems, Chaitanya Rani Veeranna Gowda Jan 2015

System Security, Threat Detection And Prevention Measures Of Autonomous Systems, Chaitanya Rani Veeranna Gowda

Electrical Engineering Theses - Archive

The Federal Aviation Administration (FAA) estimates that by the year 2020, the United States will have over 30,000 drones. Today, the fields of utilization of drones, also known as Unmanned Aerial Vehicles (UAV) are unlimited. UAVs can be used in hazardous military missions, since they exclude the risk factors involved in manned vehicles. The numerous sensors on board gather data related to the desired flight plan. This exposes UAVs to various vulnerabilities since they carry enormous information and raises safety issues and privacy concerns. Absence of manual control by a human operator over the UAV results in fraudulent information being …

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Evaluation Of Adaptive Video Optimization For Stall Minimization In Wireless Networks, Karishma Katara Jan 2015

Evaluation Of Adaptive Video Optimization For Stall Minimization In Wireless Networks, Karishma Katara

Electrical Engineering Theses - Archive

Mobile devices such as smart phones and tablets have become an integral part of peoples’ daily lives. Users are consuming more content over wireless networks than ever before, and the largest portion of that traffic by volume is delivered as video. Even with the rollout of high speed LTE networks, subscriber demand for content is growing at an overall faster rate than network capacity is being added in many urban areas. This presents a challenge to the network operators since users expect a stall-free playback experience, on devices that support high resolution and high quality content. To help maintain the …

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Self-Similarity And Modeling Of Lte / Lte-A Data Traffic, Roopesh Kumar Polaganga Jan 2015

Self-Similarity And Modeling Of Lte / Lte-A Data Traffic, Roopesh Kumar Polaganga

Electrical Engineering Theses - Archive

The mobile wireless communication system has evolved into its 4th generation with ubiquitous availability assuring higher data rates and reliable communication. To achieve a robust and reliable network, it is necessary to understand the traffic characteristics of the network. In this work, network traffic characteristics like Self-Similarity property and modeling of user arrivals are estimated for real-world LTE & LTE-Advanced (LTE-A) traffic. Lot of work has been done on Self-Similarity of Ethernet and Ad-Hoc Network's data traffic. But Self-Similarity in LTE and LTE-A data traffic has been left un-explored. Real world LTE and LTE-A data traffic collected from a live …

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Embedded Data Acquisition Platform For Low Speed Automated Surface Measurements On Asphalt, Joseph Joemon Jose Mullassery Jan 2015

Embedded Data Acquisition Platform For Low Speed Automated Surface Measurements On Asphalt, Joseph Joemon Jose Mullassery

Electrical Engineering Theses - Archive

The study is to be performed with the main goal of analyzing the existing portability and scalability problems of the existing Road profile measurement for TXDOT and improving it by making a system which is much more scalable and portable. Along with the above, another important aspect of this research study is to develop an algorithm using a new technique based on a different type of sensor viz. 3-Axis Accelerometers and compute an estimate for the IRI (International Roughness Index) using the newly obtained data from our research and previously available IRI data from earlier research efforts. The system would …

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Cacti- And Shorebirds-Inspired Transports Of Liquid Drops And Two Related Fog Collectors, Xin Heng Jan 2015

Cacti- And Shorebirds-Inspired Transports Of Liquid Drops And Two Related Fog Collectors, Xin Heng

Mechanical and Aerospace Engineering Dissertations - Archive

Motivated by what has been used in cacti and shorebirds to directionally manipulate water drops, we have explored two approaches to guide the movement of liquid drops. Based on these approaches, in addition to separating oil from its mixture with water, we have further developed two fog collectors. The first fog collector has a configuration similar to its counterpart in a cactus. This collector includes a large ZnO wire and an array of small ZnO wires that are branched on the large wire. All these wires have conical shapes, whose diameters gradually increase from the tip to the root of …

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Measurements, Modeling, And Simulation Of Semiconductor/Gate Dielectric Defects Using Random Telegraph Signals, Mohamed Assad Nour Jan 2015

Measurements, Modeling, And Simulation Of Semiconductor/Gate Dielectric Defects Using Random Telegraph Signals, Mohamed Assad Nour

Electrical Engineering Dissertations - Archive

Constructing an effective statistical model and a simulation tool that can predict the phenomenon of random telegraph signals (RTS) is the objective of this work. The continuous scaling down of metal oxide – semiconductor field effect transistors (MOSFETs) makes charging/discharging traps(s) located at the silicon/silicon dioxide interface or deep in the oxide bulk by mobile charge(s) a more pronounced problem for both analog and digital applications. The intent of this work is to develop an RTS statistical model and a simulation tool based on first principles and supported by extensive experimental data. The newly developed RTS statistical model and its …

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