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Fabrication, Characterization, Modeling And Testing Of A Nanostructured Bulk Thermoelectric Cooler, Dinesh Pinisetty 2010 Louisiana State University and Agricultural and Mechanical College

Fabrication, Characterization, Modeling And Testing Of A Nanostructured Bulk Thermoelectric Cooler, Dinesh Pinisetty

LSU Doctoral Dissertations

New generation micro/nano devices are emerging to monitor, control and act on living systems. Particularly, in the field of cryobiology, there is a need to monitor and control temperature at the cellular level. An important step towards achieving this aim is to fabricate a novel bulk nanostructured thermoelectric cooler (TEC). As a first step towards achieving efficient localized control of temperature in biological systems, Bismuth-telluride (Bi2Te3) and Antimony-Telluride (Sb2Te3) arrays of nanowires and nanotubes were fabricated, characterized and modeled. A thermal conductivity model originally developed by Dames and Chen for superlattice nanowires was extended to nanotubes. Based on this ...


Experimental And Analytical Study Of The Surface Texturing Enhanced Lubrication Elements, Yifan Qiu 2010 Louisiana State University and Agricultural and Mechanical College

Experimental And Analytical Study Of The Surface Texturing Enhanced Lubrication Elements, Yifan Qiu

LSU Doctoral Dissertations

Surface texturing is a method that modifies the frictional surface of a nominally flat tribocomponent by shallow patterns. It is found that with added patterns to the surface of a mechanical face seal or thrust bearing, their tribological performance improves, i.e. both friction and wear rate decrease. The current research concentrates on the analysis of hydrodynamic effect responsible for the performance enhancement of the spiral groove patterns and dimples on mechanical seal-like structures and the experimental evaluation of the tribological behavior of these structures. Surface textures considered are: dimple texture and spiral groove pattern. In the research on the ...


Influence Of Unstable Soil Movement On Pile-Founded Concrete Floodwalls And A Resulting Design Methodology, Richard James Varuso 2010 Louisiana State University and Agricultural and Mechanical College

Influence Of Unstable Soil Movement On Pile-Founded Concrete Floodwalls And A Resulting Design Methodology, Richard James Varuso

LSU Doctoral Dissertations

Efforts are underway in the New Orleans area to raise the elevations of its levee system to combat the effects of hurricane storm surge. When complete, the majority of the system will be comprised of a combination of levees, sheet pile I-Walls, floodgates, and pile-supported concrete floodwalls, commonly referred to as T-Walls. Given the magnitude of the hydrostatic forces associated with storm surge, global instability is failure mechanism that must be considered in the design of T-Walls. In the past, it was assumed that these forces would be resisted by the T-Wall’s sheet pile cut-off wall. Recent literature review ...


Design Techniques To Improve Time Dependent Dielectric Breakdown Based Failure For Cmos Circuits, Emanuel S. Tarog 2010 California Polytechnic State University – San Luis Obispo

Design Techniques To Improve Time Dependent Dielectric Breakdown Based Failure For Cmos Circuits, Emanuel S. Tarog

Master's Theses and Project Reports

This project investigates the failure of various CMOS circuits as a result of Time Dependent Dielectric Breakdown (TDDB) and explores design techniques to increase the mean time to failure (MTTF) of large-scale circuits. Time Dependent Dielectric Breakdown is a phenomenon where the oxide underneath the gate degrades as a result of the electric field in the material. Currently, there are few well documented design techniques that can increase lifetime, but with a tool chain I created called the MTTF Analyzing Program, or MAP, I was able to test circuits under various conditions in order to identify weak links, discover relationships ...


Merlin.Net Automation Of External Reports Verification Process, Gabriel John Wettlaufer 2010 California Polytechnic State University – San Luis Obispo

Merlin.Net Automation Of External Reports Verification Process, Gabriel John Wettlaufer

Master's Theses and Project Reports

Merlin.net Patient Care Network is a St. Jude Medical product that is used for remote patient management. The basic concept of Merlin.net is to allow the physician to view patient device follow-up information as well as general patient and device information on a web application. The Merlin.net system also interfaces with the patient and will send them notification if they miss a follow-up. All device information will be collected automatically while the patient is sleeping. This information is sent through a telephone line to a Merlin.net server to process a report package and display the collected ...


Soil Stabilization With Bioenergy Coproduct, Halil Ceylan, Kasthurirangan Gopalakrishnan, Sunghwan Kim 2010 Iowa State University

Soil Stabilization With Bioenergy Coproduct, Halil Ceylan, Kasthurirangan Gopalakrishnan, Sunghwan Kim

Civil, Construction and Environmental Engineering Publications

The production and use of biofuel have increased under the context of sustainable development. Biofuel production from plant biomass not only produces biofuel or ethanol but also coproduces products containing lignin, modified lignin, and lignin derivatives. The use of lignin-containing biofuel coproduct in pavement soil stabilization was explored as a new application area. The primary experimental test plan encompassed the comparison of coproduct-treated soils, untreated soils, and traditional stabilizer-treated soils in terms of their strengths. The focus of the secondary experimental test plan was to investigate the effect of additive combinations on strength improvement. The laboratory test matrix in each ...


Against All Probabilities: A Modeling Paradigm For Streaming Applications That Goes Against Common Notions, Rahav Dor 2010 Washington University in St Louis

Against All Probabilities: A Modeling Paradigm For Streaming Applications That Goes Against Common Notions, Rahav Dor

All Computer Science and Engineering Research

Hardware and software design requires the right portion of skills and mental faculties. The design of a good system is an exercise in rational thinking, engineering, and art. The design process is further complicated when we aspire to build systems that exploit parallelism or are targeted to be deployed on architecturally diverse computing devices, FPGAs or GPUs to name just a few. The need to develop systems that can take advantage of computing devices beyond general purpose CPUs is real. There are several application domains and research efforts that will simply not be able to adequately perform or yield answers ...


Global Constructive Optimization Of Vascular Systems, Manfred Georg, Tobias Preusser, Horst K. Hahn 2010 Washington University in St Louis

Global Constructive Optimization Of Vascular Systems, Manfred Georg, Tobias Preusser, Horst K. Hahn

All Computer Science and Engineering Research

We present a framework for the construction of vascular systems based on optimality principles of theoretical physiology. Given the position and flow distribution of end points of a vascular system, we construct the topology and positions of internal nodes to complete the vascular system in a realistic manner. Optimization is driven by intravascular volume minimization with constraints derived from physiological principles. Direct optimization of a vascular system, including topological changes, is used instead of simulating vessel growth. A good initial topology is found by extracting key information from a previously optimized model with less detail. This technique is used iteratively ...


Arch: Practical Channel Hopping For Reliable Home-Area Sensor Networks, Mo Sha, Gregory Hackmann, Chenyang Lu 2010 Washington University in St Louis

Arch: Practical Channel Hopping For Reliable Home-Area Sensor Networks, Mo Sha, Gregory Hackmann, Chenyang Lu

All Computer Science and Engineering Research

Home area networks (HANs) promise to enable sophisticated home automation applications such as smart energy usage and assisted living. However, recent empirical study of HAN reliability in real-world residential environments revealed significant challenges to achieving reliable performance in the face of significant and variable interference from a multitude of coexisting wireless devices. We propose the Adaptive and Robust Channel Hopping (ARCH) protocol: a lightweight receiveroriented protocol which handles the dynamics of residential environments by reactively channel hopping when channel conditions have degraded. ARCH has several key features. First, ARCH is an adaptive protocol that channel-hops based on changes in channel ...


Multi-Channel Reliability And Spectrum Usage In Real Homes: Empirical Studies For Home-Area Sensor Networks, Mo Sha, Gregory Hackmann, Chenyang Lu 2010 Washington University in St Louis

Multi-Channel Reliability And Spectrum Usage In Real Homes: Empirical Studies For Home-Area Sensor Networks, Mo Sha, Gregory Hackmann, Chenyang Lu

All Computer Science and Engineering Research

Home area networks (HANs) consisting of wireless sensors have emerged as the enabling technology for important applications such as smart energy and assisted living. A key challenge faced by HANs is maintaining reliable operation in real-world residential environments. This paper presents two in-depth empirical studies on the wireless channels in real homes. The spectrum study analyzes the spectrum usage in the 2.4 GHz band where wireless sensor networks based on the IEEE 802.15.4 standard must coexist with existing wireless devices. We characterize the ambient wireless environment in six apartments through passive spectrum analysis across the entire 2 ...


Optimal Time Utility Based Scheduling Policy Design For Cyber-Physical Systems , Terry Tidwell, Robert Glaubius, Christopher D. Gill, William D. Smart 2010 Washington University in St Louis

Optimal Time Utility Based Scheduling Policy Design For Cyber-Physical Systems , Terry Tidwell, Robert Glaubius, Christopher D. Gill, William D. Smart

All Computer Science and Engineering Research

Classical scheduling abstractions such as deadlines and priorities do not readily capture the complex timing semantics found in many real-time cyber-physical systems. Time utility functions provide a necessarily richer description of timing semantics, but designing utility-aware scheduling policies using them is an open research problem. In particular, optimal utility accrual scheduling design is needed for real-time cyber-physical domains. In this paper we design optimal utility accrual scheduling policies for cyber-physical systems with periodic, non-preemptable tasks that run with stochastic duration. These policies are derived by solving a Markov Decision Process formulation of the scheduling problem. We use this formulation to ...


Parametric Analysis Of A Coupled Photovoltaic/Thermal Concentrating Solar Collector For Electricity Generation, Todd Otanicar, I. Chowdhury, P. E. Phelan, R. Prasher 2010 Loyola Marymount University

Parametric Analysis Of A Coupled Photovoltaic/Thermal Concentrating Solar Collector For Electricity Generation, Todd Otanicar, I. Chowdhury, P. E. Phelan, R. Prasher

Mechanical Engineering Faculty Works

The analysis of the combined efficiencies in a coupled photovoltaic (PV)/thermal concentrating solar collector are presented based on a coupled electrical/thermal model. The calculations take into account the drop in efficiency that accompanies the operation of PV cells at elevated temperatures along with a detailed analysis of the thermal system including losses. An iterative numerical scheme is described that involves a coupled electrothermal simulation of the solar energy conversion process. In the proposed configuration losses in the PV cell due to reduced efficiencies at elevated temperatures and the incident solar energy below the PV bandgap are both harnessed ...


Nanofluid-Based Direct Absorption Solar Collector, Todd Otanicar, P. E. Phelan, R. S. Prasher, G. Rosengarten, R. A. Taylor 2010 Loyola Marymount University

Nanofluid-Based Direct Absorption Solar Collector, Todd Otanicar, P. E. Phelan, R. S. Prasher, G. Rosengarten, R. A. Taylor

Mechanical Engineering Faculty Works

Solar energy is one of the best sources of renewable energy with minimal environmental impact. Direct absorption solar collectors have been proposed for a variety of applications such as water heating; however the efficiency of these collectors is limited by the absorption properties of the working fluid, which is very poor for typical fluids used in solar collectors. It has been shown that mixing nanoparticles in a liquid (nanofluid) has a dramatic effect on the liquid thermophysical properties such as thermal conductivity. Nanoparticles also offer the potential of improving the radiative properties of liquids, leading to an increase in the ...


Distributed Turbo Product Coding Techniques Over Cooperative Communication Systems, Esam Ali Obiedat 2010 University of Mississippi

Distributed Turbo Product Coding Techniques Over Cooperative Communication Systems, Esam Ali Obiedat

Electronic Theses and Dissertations

In this dissertation, we propose a coded cooperative communications framework based on Distributed Turbo Product Code (DTPC). The system uses linear block Extended Bose-Chaudhuri-Hochquenghem (EBCH) codes as component codes. The source broadcasts the EBCH coded frames to the destination and nearby relays. Each relay constructs a product code by arranging the corrected bit sequences in rows and re-encoding them vertically using EBCH as component codes to obtain an Incremental Redundancy (IR) for source's data. Under this frame, we have investigated a number of interesting and important issues. First, to obtain, independent vertical parities from each relay in the same ...


Modeling Of Transient Response Of An Elastic Beam With Flexible Supports And Variable-Location Impact, Weiping Xu 2010 University of Mississippi

Modeling Of Transient Response Of An Elastic Beam With Flexible Supports And Variable-Location Impact, Weiping Xu

Electronic Theses and Dissertations

This research is prerequisite to determining structural health and estimating wear-limited life of contact/impact machinery components. Prevention, or at least early notification, of impact-induced wear is essential for preventing economic loss and enhancing personnel safety. Thus, an efficient model which is discrete in time and continuous in space was undertaken; an euler-bernoulli beam with adjustable boundary conditions and variable impact is numerically studied under a pulse loading. Structural stiffness, material modulus, contact stiffness, contact location, damping ratio, pulse duration, clearance and boundary conditions are investigated. A reference system is used as the basis for parameter studies and solution convergence ...


Using Bayesian Inference In Design Applications, Chung Yong Chan 2010 University of Mississippi

Using Bayesian Inference In Design Applications, Chung Yong Chan

Electronic Theses and Dissertations

This dissertation presents a new approach for solving engineering design problems such as the design of antenna arrays and finite impulse response (FIR) filters. In this approach, a design problem is cast as an inverse problem. The tools and methods previously developed for Bayesian inference are adapted and utilized to solve design problems. Given a desired design output, Bayesian parameter estimation and model comparison are employed to produce designs that meet the prescribed design specifications and requirements. In the Bayesian inference framework, the solution to a design problem is the posterior distribution, which is proportional to the product of the ...


On The Effect Of Hydrodynamic Slip On The Polarization Of A Nonconducting Spherical Particle In An Alternating Electric Field, Hui Zhao 2010 University of Nevada, Las Vegas

On The Effect Of Hydrodynamic Slip On The Polarization Of A Nonconducting Spherical Particle In An Alternating Electric Field, Hui Zhao

Mechanical Engineering Faculty Publications

The polarization of a charged, dielectric, spherical particle with a hydrodynamically slipping surface under the influence of a uniform alternating electric field is studied by solving the standard model (the Poisson–Nernst–Planck equations). The dipole moment characterizing the strength of the polarization is computed as a function of the double layer thickness, the electric field frequency, the particle’s surface charge, and the slip length. Our studies reveal that two processes contribute to the dipole moment: ion transport inside the double layer driven by the electric field and the particle’s electrophoretic motion. The hydrodynamic slip will simultaneously impact ...


Electro-Osmotic Flow Over A Charged Superhydrophobic Surface, Hui Zhao 2010 University of Nevada, Las Vegas

Electro-Osmotic Flow Over A Charged Superhydrophobic Surface, Hui Zhao

Mechanical Engineering Faculty Publications

Bubbles can be trapped inside textured structures such as grooves, forming a superhydrophobic surface. A superhydrophobic surface has a large effective hydrodynamic slip length compared to a smooth hydrophobic surface and holds the promise of enhancing electrokinetic flows that find many interesting applications in microfluidics. However, recent theoretical studies suggested that electro-osmotic flows over a weakly charged superhydrophobic surface

the zeta potential of the surface is smaller than the thermal potential (25 mV) can only be enhanced when liquid-gas interfaces are charged [T. M. Squires, Phys. Fluids 20, 092105 (2008); Bahga et al., J. Fluid Mech. 644, 245 (2010)]. So ...


High-Performance Thin-Film Garnet Materials For Magneto-Optic And Nanophotonic Applications., Mikhail Vasiliev, Mohammad Nur E Alam, Viacheslav Kotov, Kamal Alameh 2010 Edith Cowan University

High-Performance Thin-Film Garnet Materials For Magneto-Optic And Nanophotonic Applications., Mikhail Vasiliev, Mohammad Nur E Alam, Viacheslav Kotov, Kamal Alameh

ECU Publications Pre. 2011

Since the 1960's, Magneto-optic (MO) garnet materials have been studied extensively. These materials can possess world-record MO performance characteristics in terms of Faraday rotation and optical quality. Among the rear-earth-doped garnets, the Bi-substituted iron garnet is the best candidate for use as a functional material in different integrated-optics, imaging/image processing applications and also in forward-looking applications e.g. the design of metamaterials with non-reciprocal properties. We have established a set of technologies for fabricating ferrimagnetic garnet films of type (BiDy)3(FeGa)5O12 and also garnet-oxide nanocomposite (BiDy)3(FeGa)5O12 : Bi2O3 layers possessing record-high MO quality across ...


Design Of High-Sensitivity Plasmonics-Assisted Gaas Metal-Semiconductor-Metal Photodetectors, Ayman Karar, Narottam Das, Chee Leong Tan, Kamal Alameh, Yong Lee 2010 Edith Cowan University

Design Of High-Sensitivity Plasmonics-Assisted Gaas Metal-Semiconductor-Metal Photodetectors, Ayman Karar, Narottam Das, Chee Leong Tan, Kamal Alameh, Yong Lee

ECU Publications Pre. 2011

In this paper, we use the finite difference timedomain (FDTD) method to optimize the light absorption of an ultrafast plasmonic GaAs metal-semiconductor-metal photodetector (MSM-PD) employing metal nano-gratings. The MSM-PD is optimized geometrically, leading to improved light absorption near the designed wavelength of GaAs through plasmon-assisted electric and magnetic field concentration through a subwavelength aperture. Simulation results show up to 10-times light absorption enhancement at 867 nm due to surface plasmon polaritons (SPPs) propagation through the metal nano-grating, in comparison to conventional MSM-PD.


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