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Articles 2521 - 2550 of 3180

Full-Text Articles in Engineering

Computational Model For Transient And Steady State Analysis Of A 1-Dimensional Auto-Thermal Reformer, Srikanth Honavara Prasad Jan 2010

Computational Model For Transient And Steady State Analysis Of A 1-Dimensional Auto-Thermal Reformer, Srikanth Honavara Prasad

Mechanical and Aerospace Engineering Theses - Archive

This study presents a 1-dimensional mathematical model of steam reformer to be used with high temperature solid oxide fuel cell (SOFC). Steam reforming (SR) is widely used in industries to produce hydrogen from hydrocarbons. There are various physical processes associated with chemical reactions in the SR of methane such as mass, heat and momentum transport. In this study a one-dimensional SR reactor with built-in preheater and mixing chamber connected to fuel gas and steam reservoirs is modeled and analyzed. The main part of the reformer is a metallic tube with catalyst coating on the inner walls, and it can be …

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Self-Assembly Of Polystyrene Nanospheres And Its Applications As Templates For Plasmonic Structures, Shih-Hsin Chang Jan 2010

Self-Assembly Of Polystyrene Nanospheres And Its Applications As Templates For Plasmonic Structures, Shih-Hsin Chang

Material Science and Engineering Dissertations - Archive

Monodispersed colloidal polystyrene spheres have been self-assembled into various structures as templates for the fabrication of different nanostructures. Two unique self-assembly processes have been developed and systematically investigated. A method to make the multi-layer and mono-layer close-packed structure by means of capillary-convective force has been developed. By directly visualizing the self-assembling process using optical microscopy, a mechanism based on the 2-D crystal formation and 3-D repulsive force model has been proposed to explain the process. A vertical deposition technique to produce nanosphere crystal structure with single orientation on hydrophilic glass substrate has also been developed. Using a lithographically patterned substrate …

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Modeling Studies To Assess Long Term Settlement Of Light Weight Aggregate Embankment, Seema Kalla Jan 2010

Modeling Studies To Assess Long Term Settlement Of Light Weight Aggregate Embankment, Seema Kalla

Civil Engineering Theses - Archive

Expanded clay and shale (ECS) is a low weight material derived from clay and shale, and has been used in large quantities throughout the world. Very few studies have been performed to investigate the behavior of ECS and how it can reduce the settlements of embankments when used as a fill material. This thesis presents research findings of numerical modeling to assess the long term settlements of ECS embankment on a soft clay deposit and supports both pavement and traffic loading. Observed settlements near the pavement of a light weight ECS embankment built on soft clay indicated that this material …

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Field Investigations On Performance Of Short Drilled Shafts Under Inclined Loading, Richard S. Williammee Jr Jan 2010

Field Investigations On Performance Of Short Drilled Shafts Under Inclined Loading, Richard S. Williammee Jr

Civil Engineering Theses - Archive

In the Kaufman County area within the Texas Department of Transportation's Dallas District, several short drilled shaft foundations supporting three-cable median barrier systems wereobserved to be distressed during severe winter storm conditions in late 2006 through early 2007. A research study was initiated at UT Arlington to determine and understand the mechanisms causing these shaft failures. The ends of the three-cable median barrier systems are fastened to a single drilled shaft foundation. In general, these shafts are short in depth and of the same dimensions, diameter, and depth. They are typically used in all soil conditions. This paper presents the …

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Effect Of Frame Shape And Geometry On The Global Behavior Of Rigid And Hybrid Frame Under Earthquake Excitations, S.M. Ashfaqul Hoq Jan 2010

Effect Of Frame Shape And Geometry On The Global Behavior Of Rigid And Hybrid Frame Under Earthquake Excitations, S.M. Ashfaqul Hoq

Civil Engineering Theses - Archive

The primary focus of this study is to present a shape which will improve building performance in earthquake excitations. The investigation started with 3-, 9-, 12- and 20-story rectangular frame. The seismic performance is observed for different earthquake data with different frequency content. Then, the Rhombus shape is introduced to compare with the Rectangular shape frames, keeping the height-to-width ratio and loading same. For the first part of the investigation, deflection and member forces are compared between rhombus and rectangular shape considering all connections rigid. In the second part of the study partially restrained connections are introduced in mid levels …

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Investigation Of The Lower Bound Compressive And Flexural Strengths Of Conventional Concrete And Clay Masonry, Benchmark Henry Harris Jan 2010

Investigation Of The Lower Bound Compressive And Flexural Strengths Of Conventional Concrete And Clay Masonry, Benchmark Henry Harris

Civil Engineering Theses - Archive

Conventional masonry is a handcrafted product in which units are placed by hand in a mortar bedding that is prepared during construction. TMS 402 Building Code Requirements for Masonry Structures (also referred to by the industry as the Masonry Standards Joint Committee or MSJC) and referenced standards consequently permit a range of various field conditions so as to allow practical construction (1). The primary objective of the testing program was to measure a statistically significant number of test results to investigate the lower bound compressive and flexural strengths of conventional concrete and clay masonry under simulated field conditions.96 compression tests …

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Effect Of Leachate Recirculation On Methane Generation Of A Bioreactor Landfill, Shahed R. Manzur Jan 2010

Effect Of Leachate Recirculation On Methane Generation Of A Bioreactor Landfill, Shahed R. Manzur

Civil Engineering Theses - Archive

Municipal solid waste (MSW) disposal is of current concern due to the green-house effect and rising temperature all around the globe. Landfill gas is generated from aerobic & anaerobic biodegradation of organic materials in municipal solid waste (MSW) landfill. Along with leachate, generation of Methane happens to be a by-product of the entire biodegradation process in MSW landfills. Conventional landfilling or dry cell concept minimizes the amount of moisture infiltration into the waste. In contrast, Enhanced Leachate Recirculation (ELR) or bioreactor operation facilitates leachate recirculation and distribution through the landfill that leads both reduction of time for waste stabilization and …

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Complexity Reduction For Vp6 To H.264 Transcoder Using Motion Vector Reuse, Jay R. Padia Jan 2010

Complexity Reduction For Vp6 To H.264 Transcoder Using Motion Vector Reuse, Jay R. Padia

Electrical Engineering Theses - Archive

VP6 is a video coding standard developed by On2 Technologies, Inc. It is the preferred codec for Macromedia Flash 8 video. VP6 gained importance with Macromedia Flash emerging as a widely adopted video streaming technology over the internet. H.264 is currently one of the most widely accepted video coding standards in the industry. It enables high quality video at low bitrates. Adobe adopted H.264 for its Flash video in August 2007. Adobe looks at adoption of H.264 as a major step towards enabling high quality video on the web. Hence there is increasing importance of techniques which can convert video …

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Implementation And Performance Analysis Of 2-D Order 16 Integer Transforms In H.264/Avc And Avs-Video For High Definition Video Coding, Madhu Peringassery Krishnan Jan 2010

Implementation And Performance Analysis Of 2-D Order 16 Integer Transforms In H.264/Avc And Avs-Video For High Definition Video Coding, Madhu Peringassery Krishnan

Electrical Engineering Theses - Archive

H.264/AVC and AVS-video are two video coding standards that have a wide range of applications ranging from high-end professional camera and editing systems to low-end mobile applications. They strive to achieve maximum compression efficiency without compromising the quality of video. To this end many coding tools are defined in them. Transform coding is one among them. Transform coding represents the signal/image (that is currently in time/spatial domain) in another domain (transform domain), where most of the energy in signal/image is concentrated in a fewer number of coefficients. Thus the insignificant coefficients can be discarded after transform coding to achieve compression. …

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Physics Behind Rfid Smart Card Security In Context Of Privacy, Kirti Chopra Jan 2010

Physics Behind Rfid Smart Card Security In Context Of Privacy, Kirti Chopra

Electrical Engineering Theses - Archive

In this thesis I prove that existing HF protocol is not secure. Lack of security in turn leads to violation of privacy.The unique ID on the HF RFID smart card can be sniffed by any eavesdropper. Not only eavesdropping, but cloning of the card is another significant problem that poses a privacy threat. An attacker can skim the information on a proximity card and clone it to use for his malicious purposes.RFID smart cards are now widely being used in credit cards,access system, transit system and many more such application. Tampering or malicious usage of data on aforementioned cards raises …

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

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

Mechanical and Aerospace Engineering Theses - Archive

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

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

Adaptive Pain Management Decision Support System, Ching-Feng Lin

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

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

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

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

Electrical Engineering Dissertations - Archive

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

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Corporate Environmental Performance Rating Methodology, Arunapprakasini Sankaranarayanan Jan 2010

Corporate Environmental Performance Rating Methodology, Arunapprakasini Sankaranarayanan

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

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

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

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

Electrical Engineering Dissertations - Archive

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

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

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

Electrical Engineering Dissertations - Archive

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

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

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

Electrical Engineering Dissertations - Archive

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

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

Real Time Condition Monitoring Of Chemical Batteries, Anahita Banaei

Electrical Engineering Dissertations - Archive

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

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

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

Electrical Engineering Dissertations - Archive

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

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

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

Electrical Engineering Dissertations - Archive

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

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

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

Electrical Engineering Dissertations - Archive

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

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

Neuro Adaptive Control For Aerospace And Distributed Systems, Abhijit Das

Electrical Engineering Dissertations - Archive

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

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

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

Electrical Engineering Dissertations - Archive

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

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

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

Electrical Engineering Theses - Archive

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

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

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

Electrical Engineering Theses - Archive

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

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

Dispersion Engineering With Leaky-Mode Resonance Structures, Xin Wang

Electrical Engineering Theses - Archive

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

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Multiplexing Of Avs China Video With Aac Audio Bit Streams & De-Multiplexing With Lip Synchronization During Playback, Swaminathan Sridhar Jan 2010

Multiplexing Of Avs China Video With Aac Audio Bit Streams & De-Multiplexing With Lip Synchronization During Playback, Swaminathan Sridhar

Electrical Engineering Theses - Archive

AVS China is the latest digital video coding standard released by the AVS working group of China which has been proven superior to the other video coding standards such as H.261, MPEG-1 and MPEG-2 in terms of coding efficiency and reduced complexity. AVS standard employs the latest video coding tools which mainly target standard definition (SD) and high definition (HD) video compression and aim to achieve a similar coding efficiency of H.264/AVC but with reduced complexity. AVS video standard was developed in order to target broadcast and storage media applications such as digital video television, digital video disk (DVD and …

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Analysis And Improvement Of Multiple Optimal Learning Factors For Feed-Forward Networks, Praveen Jesudhas Jan 2010

Analysis And Improvement Of Multiple Optimal Learning Factors For Feed-Forward Networks, Praveen Jesudhas

Electrical Engineering Theses - Archive

The effects of transforming the net function vector in the Multilayer Perceptron (MLP) are analyzed. The use of optimal diagonal transformation matrices on the net function vector is proved to be equivalent to training the MLP using multiple optimal learning factors (MOLF). A method for linearly compressing large ill-conditioned MOLF Hessian matrices into smaller well-conditioned ones is developed. This compression approach is shown to be equivalent to using several hidden units per learning factor. The technique is extended to large networks. In simulations, the proposed algorithm performs almost as well as the Levenberg Marquardt (LM) algorithm with the computational complexity …

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

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

Bioengineering Theses - Archive

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

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

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

Bioengineering Theses - Archive

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

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