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2014

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Articles 5731 - 5760 of 7238

Full-Text Articles in Engineering

Data Center Cooling Augmentation Using Micro-Encapsulated Phase Change Material, Ruddhi Shashikumar Deshmukh Jan 2014

Data Center Cooling Augmentation Using Micro-Encapsulated Phase Change Material, Ruddhi Shashikumar Deshmukh

Mechanical and Aerospace Engineering Theses - Archive

The ever increasing information technology heat load and data center cooling energy are the main reasons to investigate the performance of microencapsulated phase change slurry over other heat transfer fluids. In recent years, more effort is being made on the development of a new technique to use the phase change materials as pump-able heat transfer fluid and as heat storage system. Thermal Energy Storage (TES) using Phase Change Materials for data centers offers a very effective method of cutting electric power costs for owners and easing demand on the power grid. Thermal storage systems have been around for decades and …

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Piper: Impact Of Power-Awareness On Social-Based Opportunistic Advertising, Soumaia Al Ayyat Jan 2014

Piper: Impact Of Power-Awareness On Social-Based Opportunistic Advertising, Soumaia Al Ayyat

Papers, Posters, and Presentations

Interest and social-awareness can be valuable determinants in decisions related to content delivery in mobile environments. Under certain conditions, we can deliver content with less cost and better delivery ratios, while only involving users that are interested in the type of content being delivered. However, the depletion of valuable power resources poses a deterrent to node participation in such interest-aware forwarding systems. No significant research contribution has been identified to collectively maximize the benefits of social, interest, and power awareness. In this work, we propose a new algorithm called PIPeR which integrates power awareness with an interest and socially aware …

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Bio-Inspired Attitude Control Of Micro Air Vehicles Using Rich Information From Airflow Sensors, He Shen Jan 2014

Bio-Inspired Attitude Control Of Micro Air Vehicles Using Rich Information From Airflow Sensors, He Shen

Electronic Theses and Dissertations

Biological phenomena found in nature can be learned and customized to obtain innovative engineering solutions. In recent years, biologists found that birds and bats use their mechanoreceptors to sense the airflow information and use this information directly to achieve their agile flight performance. Inspired by this phenomenon, an attitude control system for micro air vehicles using rich amount of airflow sensor information is proposed, designed and tested. The dissertation discusses our research findings on this topic. First, we quantified the errors between the calculated and measured lift and moment profiles using a limited number of micro pressure sensors over a …

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Self-Heating Control Of Edge Emitting And Vertical Cavity Surface Emitting Lasers, Yu Zhang Jan 2014

Self-Heating Control Of Edge Emitting And Vertical Cavity Surface Emitting Lasers, Yu Zhang

Electronic Theses and Dissertations

Self-heating leads to temperature rise of laser diode and limits the output power, efficiency and modulation bandwidth due to increased loss and decreased differential gain. The main heat sources in laser diode during continuous wave operation are Joule heating and free carrier absorption loss. To control device self-heating, the epi structure needs to be designed with low electrical resistance and low absorption loss, while the heat flux must spread out of the device efficiently. This dissertation presents the control of self-heating of both edge emitting laser diodes and vertical cavity surface emitting lasers (VCSELs). For the 980nm high power edge …

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Particle Manipulation Via Optical Forces And Engineering Soft-Matter Systems With Tunable Nonlinearities., Shima Fardad Jan 2014

Particle Manipulation Via Optical Forces And Engineering Soft-Matter Systems With Tunable Nonlinearities., Shima Fardad

Electronic Theses and Dissertations

One of the most intriguing properties of light-matter interaction is the ability of an electromagnetic field to exert mechanical forces on polarizable objects. This phenomenon is a direct consequence of the fact that light carries momentum, which in turn can be transferred to matter. Mediated by scattering, this interaction usually manifests itself as a “pushing force” in the direction of beam propagation. However, it is possible to judiciously engineer these optical forces, either by tailoring particle polarizability, and/or by structuring the incident light field. As a simple example, a tightly focused laser beam demonstrates strong gradient forces, which may attract …

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Frequency Selective Detection Of Infrared Radiation In Uncooled Optical Nano-Antenna Array, Sushrut Modak Jan 2014

Frequency Selective Detection Of Infrared Radiation In Uncooled Optical Nano-Antenna Array, Sushrut Modak

Electronic Theses and Dissertations

Mid-infrared (mid-IR) detection and imaging over atmospheric transparent 3-5 μm and 8-12 μm bands are increasingly becoming important for various space, defense and civilian applications. Various kinds of microbolometers offer uncooled detection of IR radiation. However, broadband absorption of microbolometers makes them less sensitive to spectrally resolved detection of infrared radiation and the fabrication is also very tedious involving multiple complex lithography steps. In this study, we designed an optical nano-antenna array based detector with narrow frequency band of operation. The structure consists of a two-element antenna array comprised of a perforated metallic hole array coupled with an underneath disk …

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Control Based Soft Switching Three-Phase Micro-Inverter: Efficiency And Power Density Optimization, Ahmadreza Amirahmadi Jan 2014

Control Based Soft Switching Three-Phase Micro-Inverter: Efficiency And Power Density Optimization, Ahmadreza Amirahmadi

Electronic Theses and Dissertations

In the field of renewable energy, solar photovoltaic is growing exponentially. Grid-tied PV micro-inverters have become the trend for future PV system development because of their remarkable advantages such as enhanced energy production due to MPPT implementation for each PV panel, high reliability due to redundant and distributed system architecture, and simple design, installation, and management due to its plug-and-play feature. Conventional approaches for the PV micro-inverters are mainly in the form of single-phase grid connected and they aim at the residential and commercial rooftop applications. It would be advantageous to extend the micro-inverter concept to large size PV installations …

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Human-Robot Interaction For Multi-Robot Systems, Bennie Lewis Jan 2014

Human-Robot Interaction For Multi-Robot Systems, Bennie Lewis

Electronic Theses and Dissertations

Designing an effective human-robot interaction paradigm is particularly important for complex tasks such as multi-robot manipulation that require the human and robot to work together in a tightly coupled fashion. Although increasing the number of robots can expand the area that the robots can cover within a bounded period of time, a poor human-robot interface will ultimately compromise the performance of the team of robots. However, introducing a human operator to the team of robots, does not automatically improve performance due to the difficulty of teleoperating mobile robots with manipulators. The human operator’s concentration is divided not only among multiple …

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Design And Development Of Heterogenous Combustion Systems For Lean Burn Applications, Anthony Terracciano Jan 2014

Design And Development Of Heterogenous Combustion Systems For Lean Burn Applications, Anthony Terracciano

Electronic Theses and Dissertations

Combustion with a high surface area continuous solid immersed within the flame, referred to as combustion in porous media, is an innovative approach to combustion as the solid within the flame acts as an internal regenerator distributing heat from the combustion byproducts to the upstream reactants. By including the solid structure, radiative energy extraction becomes viable, while the solid enables a vast extension of flammability limits compared to conventional flames, while offering dramatically reduced emissions of NOx and CO, and dramatically increased burning velocities. Efforts documented within are used for the development of a streamlined set of design principles, and …

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A Lab-Scale Experimental Framework For Studying The Phenomenon Of Autorotation, Sigitas Rimkus Jan 2014

A Lab-Scale Experimental Framework For Studying The Phenomenon Of Autorotation, Sigitas Rimkus

Electronic Theses and Dissertations

While wind energy has emerged as a popular source of renewable energy, the traditional wind turbine has an inherent limitation, namely that it only generates power in the presence of sufficiently high and consistent wind speeds. As a result, wind farms are typically built in areas with a high probability of the required wind speeds, which are geographically sparse. One way of overcoming this drawback is to tap into the energy available in winds at high altitudes which are not only consistent and of high magnitude, but also globally pervasive. An airborne wind energy device based upon the phenomenon of …

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Learning Collective Behavior In Multi-Relational Networks, Xi Wang Jan 2014

Learning Collective Behavior In Multi-Relational Networks, Xi Wang

Electronic Theses and Dissertations

With the rapid expansion of the Internet and WWW, the problem of analyzing social media data has received an increasing amount of attention in the past decade. The boom in social media platforms offers many possibilities to study human collective behavior and interactions on an unprecedented scale. In the past, much work has been done on the problem of learning from networked data with homogeneous topologies, where instances are explicitly or implicitly inter-connected by a single type of relationship. In contrast to traditional content-only classification methods, relational learning succeeds in improving classification performance by leveraging the correlation of the labels …

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Nonlinear Integrated Photonics On Silicon And Gallium Arsenide Substrates, Jichi Ma Jan 2014

Nonlinear Integrated Photonics On Silicon And Gallium Arsenide Substrates, Jichi Ma

Electronic Theses and Dissertations

Silicon photonics is nowadays a mature technology and is on the verge of becoming a blossoming industry. Silicon photonics has also been pursued as a platform for integrated nonlinear optics based on Raman and Kerr effects. In recent years, more futuristic directions have been pursued by various groups. For instance, the realm of silicon photonics has been expanded beyond the well-established near-infrared wavelengths and into the mid-infrared (3 - 5 µm). In this wavelength range, the omnipresent hurdle of nonlinear silicon photonics in the telecommunication band, i.e., nonlinear losses due to two-photon absorption, is inherently nonexistent. With the lack of …

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Spectrum Map And Its Application In Cognitive Radio Networks, Saptarshi Debroy Jan 2014

Spectrum Map And Its Application In Cognitive Radio Networks, Saptarshi Debroy

Electronic Theses and Dissertations

Recent measurements on radio spectrum usage have revealed the abundance of underutilized bands of spectrum that belong to licensed users. This necessitated the paradigm shift from static to dynamic spectrum access. Cognitive radio based secondary networks that utilize such unused spectrum holes in the licensed band, have been proposed as a possible solution to the spectrum crisis. The idea is to detect times when a particular licensed band is unused and use it for transmission without causing interference to the licensed user. We argue that prior knowledge about occupancy of such bands and the corresponding achievable performance metrics can potentially …

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Specialty Fiber Lasers And Novel Fiber Devices, Clemence Jollivet Jan 2014

Specialty Fiber Lasers And Novel Fiber Devices, Clemence Jollivet

Electronic Theses and Dissertations

At the Dawn of the 21st century, the field of specialty optical fibers experienced a scientific revolution with the introduction of the stack-and-draw technique, a multi-steps and advanced fiber fabrication method, which enabled the creation of well-controlled micro-structured designs. Since then, an extremely wide variety of finely tuned fiber structures have been demonstrated including novel materials and novel designs. As the complexity of the fiber design increased, highly-controlled fabrication processes became critical. To determine the ability of a novel fiber design to deliver light with properties tailored according to a specific application, several mode analysis techniques were reported, addressing the …

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Visual Analysis Of Extremely Dense Crowded Scenes, Haroon Idrees Jan 2014

Visual Analysis Of Extremely Dense Crowded Scenes, Haroon Idrees

Electronic Theses and Dissertations

Visual analysis of dense crowds is particularly challenging due to large number of individuals, occlusions, clutter, and fewer pixels per person which rarely occur in ordinary surveillance scenarios. This dissertation aims to address these challenges in images and videos of extremely dense crowds containing hundreds to thousands of humans. The goal is to tackle the fundamental problems of counting, detecting and tracking people in such images and videos using visual and contextual cues that are automatically derived from the crowded scenes. For counting in an image of extremely dense crowd, we propose to leverage multiple sources of information to compute …

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Role Of Force Resultants Interaction On Fiber Reinforced Concrete, Titchenda Chan Jan 2014

Role Of Force Resultants Interaction On Fiber Reinforced Concrete, Titchenda Chan

Electronic Theses and Dissertations

Ultra-high performance concrete (UHPC) is a recently developed concrete gaining a lot of interest worldwide, and a lot research has been conducted to determine its material properties. UHPC is known for its very high strength and high durability. Association Francaise de Genie Civil (AFGC) has defined UHPC as a concrete exhibiting compressive strength greater than 150 MPa (22 ksi). To utilize the full compressive strength of UHPC, complementary tension reinforcement is required. A recent research study to find light weight yet high strength alternative deck systems for Florida movable bridges demonstrated that a composite UHPC and high strength steel (HSS) …

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Lp Fiber Mode Converters Using Holographic Phase Mask In Photo-Thermo-Refractive Glass, Aniket Patil Jan 2014

Lp Fiber Mode Converters Using Holographic Phase Mask In Photo-Thermo-Refractive Glass, Aniket Patil

Electronic Theses and Dissertations

In this study, an investigation was undertaken to research the use of holographic phase masks (HPMs) in photo-thermo-refractive (PTR) glass as mode converters for linearly polarized (LP) fiber modes. A Spatial Light Modulator (SLM) was used to generate higher-order transverse fiber modes LPm,n. Under proper incidence condition on the holographic device, LPm,n modes are diffracted and simultaneously converted into higher order or lower order LP modes. The process was analyzed by imaging the far field on a CCD camera. It is demonstrated that using this novel method of converting transverse fiber modes several combinations of LP modes can be converted …

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A Short Window Granger Causality Approach To Identify Brain Functional Pattern Associated With Changes Of Performance Induced By Sleep Deprivation, Muyuan Li Jan 2014

A Short Window Granger Causality Approach To Identify Brain Functional Pattern Associated With Changes Of Performance Induced By Sleep Deprivation, Muyuan Li

Electronic Theses and Dissertations

The comprehensive effect of sleep deprivation on biological and behavioral functions largely remains unknown. There is evidence to support that human sleep must be of sufficient duration and physiological continuity to ensure neurocognitive performance while we are waking. Insufficient sleep would lead to high risk of human-error related to accidents, injuries or even fatal outcomes. However, in modern society, more and more people suffer from sleep deprivation because of the increasing social, academic or occupational demand. It is important to study the effect of sleep deprivation, not only on task performance, but also on neurocognitive functions. Recent research that has …

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Advanced Liquid Crystal Materials For Display And Photonic Applications, Yuan Chen Jan 2014

Advanced Liquid Crystal Materials For Display And Photonic Applications, Yuan Chen

Electronic Theses and Dissertations

Thin-film-transistor (TFT) liquid crystal display (LCD) has been widely used in smartphones, pads, laptops, computer monitors, and large screen televisions, just to name a few. A great deal of effort has been delved into wide viewing angle, high resolution, low power consumption, and vivid color. However, relatively slow response time and low transmittance remain as technical challenges. To improve response time, several approaches have been developed, such as low viscosity liquid crystals, overdrive and undershoot voltage schemes, thin cell gap with a high birefringence liquid crystal, and elevated temperature operation. The state-of-the-art gray-to-gray response time of a nematic LC device …

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Generation And Characterization Of Sub-70 Isolated Attosecond Pulses, Qi Zhang Jan 2014

Generation And Characterization Of Sub-70 Isolated Attosecond Pulses, Qi Zhang

Electronic Theses and Dissertations

Dynamics occurring on microscopic scales, such as electronic motion inside atoms and molecules, are governed by quantum mechanics. However, the Schroedinger equation is usually too complicated to solve analytically for systems other than the hydrogen atom. Even for some simple atoms such as helium, it still takes months to do a full numerical analysis. Therefore, practical problems are often solved only after simplification. The results are then compared with the experimental outcome in both the spectral and temporal domain. For accurate experimental comparison, temporal resolution on the attosecond scale is required. This had not been achieved until the first demonstration …

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High Performance Three-Dimensional Display Based On Polymer-Stabilized Blue Phase Liquid Crystal, Yifan Liu Jan 2014

High Performance Three-Dimensional Display Based On Polymer-Stabilized Blue Phase Liquid Crystal, Yifan Liu

Electronic Theses and Dissertations

Autostereoscopic 2D/3D (two-dimension/three-dimension) switchable display has been attracting great interest in research and practical applications for several years. Among different autostereoscopic solutions, direction-multiplexed 3D displays based on microlens array or parallax barrier are viewed as the most promising candidates, due to their compatibility with conventional 2D display technologies. These 2D/3D switchable display system designs rely on fast switching display panels and photonics devices, including adaptive focus microlens array and switchable slit array. Polymer-stabilized blue phase liquid crystal (PS-BPLC) material provides a possible solution to meet the aforementioned fast response time requirement. However, present display and photonic devices based on blue …

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Holographic Recording And Applications Of Multiplexed Volume Bragg Gratings In Photo-Thermo-Refractive Glass, Daniel Ott Jan 2014

Holographic Recording And Applications Of Multiplexed Volume Bragg Gratings In Photo-Thermo-Refractive Glass, Daniel Ott

Electronic Theses and Dissertations

Recent developments in holographic recording of volume Bragg gratings (VBGs) in photo-thermo-refractive (PTR) glass have demonstrated their utility as components in high power laser systems for spectral narrowing, transverse mode control, beam combining, and pulse stretching/compression. VBG structures are capable of diffracting incident light into a single diffraction order with high efficiency given the Bragg condition is met. The Bragg condition depends on both the wavelength and angle of the incident light making VBGs useful for filtering and manipulating both the wavelength and angular spectrum of a source. This dissertation expands upon previous research in PTR VBGs by investigating multiplexed …

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Human Detection, Tracking And Segmentation In Surveillance Video, Guang Shu Jan 2014

Human Detection, Tracking And Segmentation In Surveillance Video, Guang Shu

Electronic Theses and Dissertations

This dissertation addresses the problem of human detection and tracking in surveillance videos. Even though this is a well-explored topic, many challenges remain when confronted with data from real world situations. These challenges include appearance variation, illumination changes, camera motion, cluttered scenes and occlusion. In this dissertation several novel methods for improving on the current state of human detection and tracking based on learning scene-specific information in video feeds are proposed. Firstly, we propose a novel method for human detection which employs unsupervised learning and superpixel segmentation. The performance of generic human detectors is usually degraded in unconstrained video environments …

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Entangled Photon Pairs In Disordered Photonic Lattices, Lane Martin Jan 2014

Entangled Photon Pairs In Disordered Photonic Lattices, Lane Martin

Electronic Theses and Dissertations

Photonic lattices consisting of arrays of evanescently coupled waveguides fabricated with precisely controlled parameters have enabled the study of discrete optical phenomena, both classical and quantum, and the simulation of other physical phenomena governed by the same dynamics. In this dissertation, I have experimentally demonstrated transverse Anderson localization of classical light in arrays with off-diagonal coupling disorder and investigated theoretically and experimentally the propagation of entangled photon pairs through such disordered systems. I discovered a new phenomenon, Anderson co-localization, in which a spatially entangled photon pair in a correlated transversally extended state localizes in the correlation space, though neither photon …

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Electroplated Micro- And Nanoscale Structures For Emitters And Sensors, Xiaochen Wang Jan 2014

Electroplated Micro- And Nanoscale Structures For Emitters And Sensors, Xiaochen Wang

Electronic Theses and Dissertations

In the electroplating process, dissolved metal cations are reduced by electrical current to a form a coherent metal coating on an electrode. Therefore, electroplating is primarily applied to modify the surface properties of an object (e.g. abrasion and wear resistance, corrosion protection, lubricity, aesthetic qualities, etc.), but also be applied to build up high aspect ratio structures on undersized parts or to form devices by electroforming. Compared with other common MEMS (microelectromechanical systems) metal device fabrication techniques, such as vapor depositions, electroplating has several outstanding advantages. First, the fabrication process is cost-efficient because electroplating process can be set up easily …

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Complexity Reduction Of Motion Estimation In Hevc, Jayesh Dubhashi Jan 2014

Complexity Reduction Of Motion Estimation In Hevc, Jayesh Dubhashi

Electrical Engineering Theses - Archive

The High Efficiency Video Coding (HEVC) standard is the latest video coding project developed by the Joint Collaborative Team on Video Coding (JCT-VC) which involves the International Telecommunication Unit (ITU-T) Video Coding Experts Group (VCEG) and the ISO/IEC Moving Picture Experts Group (MPEG) standardization organizations. The HEVC standard is an optimization of the previous standard H.264/AVC (Advanced Video coding) with the bit-rate reduction of about 50% at the same visual quality.The most complex and time consuming process in the HEVC encoding is the motion estimation. The process involves finding the best matching block in the current frame by comparing it …

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New Operations On Intuitionistic Fuzzy Soft Sets Based On First Zadeh's Logical Operators, Florentin Smarandache, Said Broumi, Pinaki Majumdar Jan 2014

New Operations On Intuitionistic Fuzzy Soft Sets Based On First Zadeh's Logical Operators, Florentin Smarandache, Said Broumi, Pinaki Majumdar

Branch Mathematics and Statistics Faculty and Staff Publications

In this paper , we have defined First Zadeh’s implication , First Zadeh’s intuitionistic fuzzy conjunction and intuitionistic fuzzy disjunction of two intuitionistic fuzzy soft sets and some their basic properties are studied with proofs and examples.

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Art Or Science?, Allison Marsh Jan 2014

Art Or Science?, Allison Marsh

Section 3: Imaging the Fast Moving

No abstract provided.

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Eece 7907/8907: Computational Science & Engineering (Syllabus), Madhusudhanan Balasubramanian Jan 2014

Eece 7907/8907: Computational Science & Engineering (Syllabus), Madhusudhanan Balasubramanian

Electrical and Computer Engineering Syllabi Archive

Course Description: Scientific computing is a powerful approach to study and solve engineering, scientific, and interdisciplinary biomedical problems involving complex geometrical structure and function. The following topics are covered in this class to learn the theoretical foundation, to program and to use the finite element method to solve linear boundary value problems in 1-D and 2-D: 1) Review of tools and methods from ordinary differential equations, partial differential equations, and calculus of variation for solving boundary value problems; 2) Review of Hilbert and Banach spaces; 3) Overview of finite difference and finite element methods for solving boundary value problems; 4) …

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Eece 7903/8903: Computational Science & Engineering Ii: Fluid Flow (Syllabus), Madhusudhanan Balasubramanian Jan 2014

Eece 7903/8903: Computational Science & Engineering Ii: Fluid Flow (Syllabus), Madhusudhanan Balasubramanian

Electrical and Computer Engineering Syllabi Archive

Course Description: Modeling of transport phenomena from governing physical principles (e.g. fluid flow) and numerical analysis of the underlying differential equations have a broad spectrum of applications ranging from biomedicine, engineering design and simulation, aerodynamics, weather forecasting to animated motion pictures. Topics covered will emphasize on a collective learning of physical phenomena and theoretical models that govern fluid flow, mathematical formulation, numerical analysis and visualization of fluid flow. Particular emphasis will be on mathematical development of finite-element methods for incompressible Navier-Stokes equations governing fluid flow in a non-moving domain. Class projects will be structured to aid learning key theoretical concepts …

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