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Articles 901 - 930 of 4566

Full-Text Articles in Engineering

Adsorption Capacity Assessment Of Advance Green Environmental Media To Remove Nutrients From Stormwater-Runoff, Hanan Elhakiem Jan 2019

Adsorption Capacity Assessment Of Advance Green Environmental Media To Remove Nutrients From Stormwater-Runoff, Hanan Elhakiem

Electronic Theses and Dissertations

Best Management Practices (BMPs) in stormwater treatment are a suite of treatment alternatives to deal with pollutant removal problems from stormwater runoff. Biosorption-activated media (BAM) are green sorption media consists of recycled materials have shown excellent nutrient removal as an effective BMP by enhancing physicochemical and microbiological processes. In this study, Iron-Filling Green Environmental Media (denoted as IFGEM-3) and Advanced Green Environmental Media 1 and 2 (denoted as AGEM-1 and AGEM-2) were produced and tested for their adsorption capacities as well as removal and recovery potential for phosphate, nitrate, and ammonia against natural soil (baseline) collected from a stormwater retention …

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Mode Conversions In Active Semiconductor Mqw Integrated Optics Devices, Yousef Alahmadi Jan 2019

Mode Conversions In Active Semiconductor Mqw Integrated Optics Devices, Yousef Alahmadi

Electronic Theses and Dissertations

Optical communication systems had successfully met the increasing demands for higher communication speeds through the utilization of all degrees of freedom of the light propagating in a single-mode fiber (SMF). However, the Shannon limit restricts further improvements of the capacity in the SMFs. Space-division multiplexing (SDM) offers a way for further increasing the capacity of optical fibers through the utilization of the spatial domain. However, for it to be successfully implemented, many integral parts of the optical communication must be tuned or modified to work effectively with the multimode fibers, including few-mode amplifiers, and mode converters. In this work, we …

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Simulation Analysis Of A Ventilated Building Integrated Photovoltaic Air-Gap Duct System For Natural Ventilation Of A Building, Arash Zarmehr Jan 2019

Simulation Analysis Of A Ventilated Building Integrated Photovoltaic Air-Gap Duct System For Natural Ventilation Of A Building, Arash Zarmehr

Electronic Theses and Dissertations

We introduce a low-cost and low-maintenance wind-catcher duct system design addition to BIPV systems that increase airflow velocity and decrease air temperature resulting in increased performance for the PV system electricity output. The results of our work demonstrate the design can further enhance energy performance by utilizing the increased airflow from the duct system to naturally ventilate an attic. Similar benefits were observed for different variations of the design under a parametric analysis finding the most optimal configuration to increase airflow velocity and decrease temperature. Building integrated photovoltaics (BIPV) is becoming more popular and widely used to increase sustainability and …

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Multiphase Flow Modeling Of Molten Metal Atomization At High Gas Pressure, Kalpana Hanthanan Arachchilage Jan 2019

Multiphase Flow Modeling Of Molten Metal Atomization At High Gas Pressure, Kalpana Hanthanan Arachchilage

Electronic Theses and Dissertations

The high-pressure gas atomization is well known as one of the best powder manufacturing processes due to its controllability over powder size distribution. However, with the continuous improvement of new alloys, optimizing the operating parameters to maximize the yield is costly and time-consuming. Therefore, it is essential to understand the high-pressure gas atomization process and the effects of different operational parameters on the powder size distribution. Two-phase numerical simulations are performed to capture the interfacial dynamic during the atomization process and to obtain the effects of gas pressure, melt flow rate, and thermophysical properties of atomizing gas and the molten …

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A Framework To Develop Anomaly Detection/Fault Isolation Architecture Using System Engineering Principles, Thomas Clark Jan 2019

A Framework To Develop Anomaly Detection/Fault Isolation Architecture Using System Engineering Principles, Thomas Clark

Electronic Theses and Dissertations

For critical systems, timely recognition of an anomalous condition immediately starts the evaluation process. For complex systems, isolating the fault to a component or subsystem results in corrective action sooner so that undesired consequences may be minimized. There are many unique anomaly detection and fault isolation capabilities available with innovative techniques to quickly discover an issue and identify the underlying problems. This research develops a framework to aid in the selection of appropriate anomaly detection and fault isolation technology to augment a given system. To optimize this process, the framework employs a model based systems engineering approach. Specifically, a SysML …

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Autonomous Robotic Grasping In Unstructured Environments, Amirhossein Jabalameli Jan 2019

Autonomous Robotic Grasping In Unstructured Environments, Amirhossein Jabalameli

Electronic Theses and Dissertations

A crucial problem in robotics is interacting with known or novel objects in unstructured environments. While the convergence of a multitude of research advances is required to address this problem, our goal is to describe a framework that employs the robot's visual perception to identify and execute an appropriate grasp to pick and place novel objects. Analytical approaches explore for solutions through kinematic and dynamic formulations. On the other hand, data-driven methods retrieve grasps according to their prior knowledge of either the target object, human experience, or through information obtained from acquired data. In this dissertation, we propose a framework …

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Piezoresistive Behavior Of Carbon Nanopaper Polymer Composites For Strain Sensing, Jayden Beyrooti Jan 2019

Piezoresistive Behavior Of Carbon Nanopaper Polymer Composites For Strain Sensing, Jayden Beyrooti

Electronic Theses and Dissertations

Carbon nanopapers made of carbon nanotubes (CNTs) or carbon nanofibers (CNFs), possess unique electrical, thermal and mechanical properties and when integrated with a polymer matrix, can become a multifunctional composite capable of strain sensing and heat actuation. Smart structures such as these can be used in many applications including deployable space structures, human motion detection, and structural health monitoring as flexible, sensitive and stable strain sensors in addition to providing electrical heat actuation for the shape memory effect in polymers. This study focuses on strain sensing capabilities by developing a numerical model to predict piezoresistive behavior. The piezoresistive effect is …

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Optimal Recipe Screening And Applications Of Iron-Filings Based Green Environmental Media (Ifgem) For Stormwater Treatment, Andrea Valencia Jan 2019

Optimal Recipe Screening And Applications Of Iron-Filings Based Green Environmental Media (Ifgem) For Stormwater Treatment, Andrea Valencia

Electronic Theses and Dissertations

The applications of green sorption media for stormwater treatment and nutrient removal benefit surface and ground water bodies by reducing non-point source pollution from stormwater runoff. To enhance nitrogen and phosphorus removal, a sequential study was performed to develop an improved green sorption media in this study by including the iron filings into the previous biosorption activated media (BAM). The iron-filings-based green environmental media (IFGEM) are thus composed of sand, tire crumb, clay and ground iron filings in which clay and iron particles are supposed to have salient interactions that cannot be present in BAM. However, the optimal ratio between …

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Modeling And Transient Simulation Of A Fully Integrated Multi-Pressure Heat Recovery Steam Generator Using Siemens T3000, Jonathan Mcconnell Jan 2019

Modeling And Transient Simulation Of A Fully Integrated Multi-Pressure Heat Recovery Steam Generator Using Siemens T3000, Jonathan Mcconnell

Electronic Theses and Dissertations

The focus of this research is on the transient thermodynamic properties and dynamic behavior of a Heat Recovery Steam Generator (HRSG). An HRSG is a crossflow heat exchanger designed for the extraction of energy from the hot exhaust gas of a traditional power plant through boiling induced phase change. Superheated steam is sent through a turbine to generate additional power, raising the overall efficiency of a power plant. The addition of renewable energies and the evolution of smart grids have brought forth a necessity to gain a comprehensive understanding of transient behavior within an HRSG in order to efficiently manage …

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The Challenges And Barriers To Employment For Female In Riyadh And Tabuk, Sultan Almutairi Jan 2019

The Challenges And Barriers To Employment For Female In Riyadh And Tabuk, Sultan Almutairi

Electronic Theses and Dissertations

Women labor force participation plays an important role in economic. The developing in economy in Saudi Arabia depends on men rather than women, more than 50 years the Saudi women participation in the labor force extremely is low, this dissertation seeks to identify the challenges and barriers to employment for women in Riyadh and Tabuk. This study examines three research questions. The first question explored the difference between the rate of women unemployment in Tabuk and the rate of women unemployment in Riyadh. The second question investigated ways in which a logistic regression using demographics data could be used to …

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Modeling Of Wrong Way Driving Entries And Developing Innovative Approaches For Evaluating The Effectiveness Of Advanced Wrong Way Driving Countermeasures, Md Imrul Kayes Jan 2019

Modeling Of Wrong Way Driving Entries And Developing Innovative Approaches For Evaluating The Effectiveness Of Advanced Wrong Way Driving Countermeasures, Md Imrul Kayes

Electronic Theses and Dissertations

Wrong-way driving (WWD) is a hazardous behavior on interstates, toll roads, and other high-speed limited access facilities. Since WWD crashes are rare, recent researchers have studied WWD events such as WWD 911 calls and WWD citations to understand the overall nature and trend of WWD. It is very difficult to build credible statistical models based solely on crashes due to the small sample size since these are only 3% of all crashes. Modeling of WWD non-crash events can result in more accurate models. A model was developed for Florida limited access facilities to identify roadway factors and traffic characteristics of …

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Sparse Signal Recovery Under Sensing And Physical Hardware Constraints, Davood Mardaninajafabadi Jan 2019

Sparse Signal Recovery Under Sensing And Physical Hardware Constraints, Davood Mardaninajafabadi

Electronic Theses and Dissertations

This dissertation focuses on information recovery under two general types of sensing constraints and hardware limitations that arise in practical data acquisition systems. We study the effects of these practical limitations in the context of signal recovery problems from interferometric measurements such as for optical mode analysis. The first constraint stems from the limited number of degrees of freedom of an information gathering system, which gives rise to highly constrained sensing structures. In contrast to prior work on compressive signal recovery which relies for the most part on introducing additional hardware components to emulate randomization, we establish performance guarantees for …

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Investigation Of The Effect Of Edge-Oxidized Graphene Oxide (Eogo) On The Properties Of Cement Composites, Yousef Alharbi Jan 2019

Investigation Of The Effect Of Edge-Oxidized Graphene Oxide (Eogo) On The Properties Of Cement Composites, Yousef Alharbi

Electronic Theses and Dissertations

The use of edge-oxidized graphene oxide (EOGO), produced by a mechanochemical process that allow to deliver a product suitable for large-scale production at affordable cost, as an additive in cement composites was investigated. Comprehensive experimental tests were conducted to investigate the effect of EOGO on the properties of cement composites. The experimental tests were designed for three subtasks: (1) investigation of the performance of EOGO and its mixing method on the strength, pore structure and microstructure of EOGO-cement composites, (2) evaluation of the rheological and fluidity behavior of EOGO-cement paste and mortar, and (3) investigation of the mechanism of the …

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Development Of Decision Support System For Active Traffic Management Systems Considering Travel Time Reliability, Whoibin Chung Jan 2019

Development Of Decision Support System For Active Traffic Management Systems Considering Travel Time Reliability, Whoibin Chung

Electronic Theses and Dissertations

As traffic problems on roadways have been increasing, active traffic management systems (ATM) using proactive traffic management concept have been deployed on freeways and arterials. The ATM aims to integrate and automate various traffic control strategies such as variable speed limits, queue warning, and ramp metering through a decision support system (DSS). Over the past decade, there have been many efforts to integrate freeways and arterials for the efficient operation of roadway networks. It has been required that these systems should prove their effectiveness in terms of travel time reliability. Therefore, this study aims to develop a new concept of …

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A System Dynamics Approach On Sustainability Assessment Of The United States Urban Commuter Transportation, Tolga Ercan Jan 2019

A System Dynamics Approach On Sustainability Assessment Of The United States Urban Commuter Transportation, Tolga Ercan

Electronic Theses and Dissertations

Transportation sector is one of the largest emission sources and is a cause for human health concern due to the high dependency on personal vehicle in the U.S. Transportation mode choice studies are currently limited to micro- and regional-level boundaries, lacking of presenting a complete picture of the issues, and the root causes associated with urban passenger transportation choices in the U.S. Hence, system dynamics modeling approach is utilized to capture complex causal relationships among the critical system parameters affecting alternative transportation mode choices in the U.S. as well as to identify possible policy areas to improve alternative transportation mode …

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Shape Recovery Behavior Of Carbon Nanopaper Shape Memory Polymer Composite, Veli Bugra Ozdemir Jan 2019

Shape Recovery Behavior Of Carbon Nanopaper Shape Memory Polymer Composite, Veli Bugra Ozdemir

Electronic Theses and Dissertations

This thesis presents analytical, experimental and modeling studies of the shape recovery behavior of electrically activated Carbon Nanopaper (CNP) Shape Memory Polymer (SMP)composite. The composite structure studied consists of a CNP layer sandwiched by two SMP layers where the CNP layer acts as a flexible electrical heater when a voltage difference is applied. The behavior of CNP/SMP composite presents a coupled electrical - thermal - structural problem. The governing equations for the multiphysics behavior are derived. Derived parameters as a result of multiphysics analysis and effects of these parameters on the shape recovery behavior are investigated. The mechanical properties of …

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Nonlinear Control Synthesis For Facilitation Of Human-Robot Interaction, Zhangchi Ding Jan 2019

Nonlinear Control Synthesis For Facilitation Of Human-Robot Interaction, Zhangchi Ding

Electronic Theses and Dissertations

Human-robot interaction is an area of interest that is becoming increasingly important in robotics research. Nonlinear control design techniques allow researchers to guarantee stability, performance, as well as safety, especially in cases involving physical human-robot interaction (PHRI). In this dissertation, we will propose two different nonlinear controllers and detail the design of an assistive robotic system to facilitate human-robot interaction. In Chapter 2, to facilitate physical human-robot interaction, the problem of making a safe compliant contact between a human and an assistive robot is considered. Users with disabilities have a need to utilize their assistive robots for physical interaction during …

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Fundamental Characteristics Of Supercritical Co2 Combustion, Raghu Veera Manikantachari Kancherla Jan 2019

Fundamental Characteristics Of Supercritical Co2 Combustion, Raghu Veera Manikantachari Kancherla

Electronic Theses and Dissertations

The direct-fired supercritical CO2 (sCO2) cycle is conceptually superior to many of the trending energy production technologies due to their remarkably promising efficiency, environmental friendliness and cost. The accurate simulation of this combustion is very important because the operating conditions are very challenging to its experimentation. Hence, the current work focuses on identifying various thermal, transport, chemical kinetic models, investigating various fundamental characteristics and verifying the validity of important underlying modeling assumptions in focus to supercritical CO2 combustion. In the current work, various thermal and transport property models are identified based on accuracy, computational cost and ease of implementation for …

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Scalable Map Information Dissemination For Connected And Automated Vehicle Systems, S. M. Osman Gani Jan 2019

Scalable Map Information Dissemination For Connected And Automated Vehicle Systems, S. M. Osman Gani

Electronic Theses and Dissertations

Situational awareness in connected and automated vehicle (CAV) systems becomes particularly challenging in the presence of non-line of sight objects and/or objects beyond the sensing range of local onboard sensors. Despite the fact that fully autonomous driving requires the use of multiple redundant sensor systems, primarily including camera, radar, and LiDAR, the non-line of sight object detection problem still persists due to the inherent limitations of those sensing techniques. To tackle this challenge, the inter-vehicle communication system is envisioned that allows vehicles to exchange self-status updates aiming to extend their effective field of view and thus compensate for the limitations …

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Frequency-Reconfigurable Microstrip Patch And Cavity-Backed Slot Espars, Wei Ouyang Jan 2019

Frequency-Reconfigurable Microstrip Patch And Cavity-Backed Slot Espars, Wei Ouyang

Electronic Theses and Dissertations

Wireless communication systems have rapidly evolved over the past decade which has led to an explosion of mobile data traffic. Since more and more wireless devices and sensors are being connected, the transition from the current 4G/LTE mobile network to 5G is expected to happen within the next decade. In order to improve signal-to-noise ratio (SNR), system capacity, and link budget, beam steerable antenna arrays are desirable due to their advantage in spatial selectivity and high directivity. Electronically steerable parasitic array radiator (ESPAR) that can achieve low-cost continuously beamsteering using varactor diodes have attracted a lot of attention. This dissertation …

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A Methodology For Data-Driven Decision-Making In Last Mile Delivery Operations, Edgar Gutierrez Franco Jan 2019

A Methodology For Data-Driven Decision-Making In Last Mile Delivery Operations, Edgar Gutierrez Franco

Electronic Theses and Dissertations

Across all industries, from manufacturing to services, decision-makers must deal day to day with the outcomes from past and current decisions that affect their business. Last-mile delivery is the term used in supply chain management to describe the movement of goods from a hub to final destinations. This research proposes a methodology that supports decision making for the execution of last-mile delivery operations in a supply chain. This methodology offers diverse, hybrid, and complementary techniques (e.g., optimization, simulation, machine learning, and geographic information systems) to understand last-mile delivery operations through data-driven decision-making. The hybrid modeling might create better warning systems …

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Saw Correlator Temperature Compensation Using A Pulse Width Modulated Temperature Controller, Daniel Betancourt Jan 2019

Saw Correlator Temperature Compensation Using A Pulse Width Modulated Temperature Controller, Daniel Betancourt

Electronic Theses and Dissertations

A Surface Acoustic Wave (SAW) correlator built on a Lithium Niobate substrate is temperature compensated in order to maintain a constant center frequency. Frequency shifts as a result of temperature variations limit device performance. An Arduino®-based PWM temperature controller is developed to read the device temperature from a resistance temperature detector located on the SAW wafer and to regulate its temperature to a specified setpoint by providing current to a heater which is co-located with the temperature sensor on the SAW correlator substrate. The final temperature controller achieves frequency shifts of 0.013 MHz from room temperature with a worst-case PPM …

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Machine Learning And Neural Networks For Real-Time Scheduling, Daniel Hureira, Christian Vartanian Jan 2019

Machine Learning And Neural Networks For Real-Time Scheduling, Daniel Hureira, Christian Vartanian

Recent Advances in Real-Time Systems

This paper aims to serve as an efficient survey of the processes, problems, and methodologies surrounding the use of Neural Networks, specifically Hopfield-Type, in order to solve Hard-Real-Time Scheduling problems. Our primary goal is to demystify the field of Neural Networks research and properly describe the methods in which Real-Time scheduling problems may be approached when using neural networks. Furthermore, to give an introduction of sorts on this niche topic in a niche field. This survey is derived from four main papers, namely: “A Neurodynamic Approach for Real-Time Scheduling via Maximizing Piecewise Linear Utility” and “Scheduling Multiprocessor Job with Resource …

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Experiment And Computational Analysis On Effect Of Plasma Actuation Incompressible Flow Around Tandem Cylinders, Emmanuel C. Gabriel-Ohanu Jan 2019

Experiment And Computational Analysis On Effect Of Plasma Actuation Incompressible Flow Around Tandem Cylinders, Emmanuel C. Gabriel-Ohanu

Honors Undergraduate Theses

The utilization of steady state flow of air over tandem circular cylinders has several applications in engineering systems. Incompressible flow over circular cylinders in tandem at different spacing with and without plasma actuation on the leading cylinder will be investigated in this paper to understand the effects of plasma actuation on flow properties and wake region of the two cylinders in cross flow. The principal focus of the research is on the use of experimental and computational methods to study and provide valid results, the research will analyze the wake region, the effect of Reynolds number and the longitudinal spacing …

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Comparative Nutrient Removal With Innovative Green Soprtion Media For Groundwater And Stormwater Co-Treatment, Dan Wen Jan 2019

Comparative Nutrient Removal With Innovative Green Soprtion Media For Groundwater And Stormwater Co-Treatment, Dan Wen

Electronic Theses and Dissertations

As indicated by the National Academy of Engineering, the understanding of nitrogen cycle has been deemed as one of 14 grand challenges in engineering of the 21st century. Due to rapid population growth and urbanization, the stormwater runoff increased in quantity as well as its nutrient concentrations, which may trigger serious environmental issues such as eutrophication in aquatic systems and ecosystem degradation. This study focuses on stormwater and groundwater quality control via Biosorption Activated Media (BAM) which can be applied to enhance the nutrient removal potential as an emerging Best Management Practices (BMPs). BAM was tested in this study with …

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Developing A Traffic Safety Diagnostics System For Unmanned Aerial Vehicles Usingdeep Learning Algorithms, Ou Zheng Jan 2019

Developing A Traffic Safety Diagnostics System For Unmanned Aerial Vehicles Usingdeep Learning Algorithms, Ou Zheng

Electronic Theses and Dissertations

This thesis presents an automated traffic safety diagnostics solution using deep learning techniques to process traffic videos by Unmanned Aerial Vehicle (UAV). Mask R-CNN is employed to better detect vehicles in UAV videos after video stabilization. The vehicle trajectories are generated when tracking the detected vehicle by Channel and Spatial Reliability Tracking (CSRT) algorithm. During the detection process, missing vehicles could be tracked by the process of identifying stopped vehicles and comparing Intersect of Union (IOU) between the tracking results and the detection results. In addition, rotated bounding rectangles based on the pixel-to- pixel manner masks that are generated by …

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Investigation Of Computer Vision Concepts And Methods For Structural Health Monitoring And Identification Applications, Chuanzhi Dong Jan 2019

Investigation Of Computer Vision Concepts And Methods For Structural Health Monitoring And Identification Applications, Chuanzhi Dong

Electronic Theses and Dissertations

This study presents a comprehensive investigation of methods and technologies for developing a computer vision-based framework for Structural Health Monitoring (SHM) and Structural Identification (St-Id) for civil infrastructure systems, with particular emphasis on various types of bridges. SHM is implemented on various structures over the last two decades, yet, there are some issues such as considerable cost, field implementation time and excessive labor needs for the instrumentation of sensors, cable wiring work and possible interruptions during implementation. These issues make it only viable when major investments for SHM are warranted for decision making. For other cases, there needs to be …

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Fabrication And Characterization Of Nonlinear Optical Ceramics For Random Quasi-Phase-Matching, Xuan Chen Jan 2019

Fabrication And Characterization Of Nonlinear Optical Ceramics For Random Quasi-Phase-Matching, Xuan Chen

Electronic Theses and Dissertations

A number of technologies rely on the conversion of short laser pulses from one spectral domain to another. Efficient frequency conversion is currently obtained in ordered nonlinear optical materials and requires a periodic spatial modulation of their nonlinear coefficient which results in a narrow bandwidth. One can trade off efficiency for more spectral bandwidth by relaxing the strict phase-matching conditions and achieve nonlinear interaction in carefully engineered disordered crystalline aggregates, in a so-called random quasi-phase-matching (rQPM) process. In this dissertation, we examine appropriate fabrication pathways for (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT) and ZnSe transparent ceramics for applications in the mid-IR. The main challenge …

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Numerical Investigation And Optimization Of Pin Fins In Micro Heat Sinks, Fuad Ismayilov Jan 2019

Numerical Investigation And Optimization Of Pin Fins In Micro Heat Sinks, Fuad Ismayilov

Electronic Theses and Dissertations

Operating temperature in electronics applications is continuously increasing. Therefore, for the past few decades, high heat flux removing micro heat sinks are investigated in terms of heat transfer effectiveness. This study generally concentrates on improving the passive heat transfer techniques. Micro heat sinks used in experiments are fabricated using MEMS techniques. Resistance temperature detectors, RTDs, were used for temperature measurements. The experimental data was obtained for single and two phase flow regions; however, only single phase flow results were considered in numerical simulations. Numerical validations were performed on the micro heat sinks, including cylinder and hydrofoil shaped pin fins. Following …

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Mode Coupling In Space-Division Multiplexed Systems, Huiyuan Liu Jan 2019

Mode Coupling In Space-Division Multiplexed Systems, Huiyuan Liu

Electronic Theses and Dissertations

Even though fiber-optic communication systems have been engineered to nearly approach the Shannon capacity limit, they still cannot meet the exponentially-growing bandwidth demand of the Internet. Space-division multiplexing (SDM) has attracted considerable attention in recent years due to its potential to address this capacity crunch. In SDM, the transmission channels support more than one spatial mode, each of which can provide the same capacity as a single-mode fiber. To make SDM practical, crosstalk among modes must be effectively managed. This dissertation presents three techniques for crosstalk management for SDM. In some cases such as intra-datacenter interconnects, even though mode crosstalk …

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