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Articles 2161 - 2190 of 3180

Full-Text Articles in Engineering

Infrared Imaging Method For Thermographic Characterizing Of Medical High Intensity Focused Ultrasound Devices, Mohammadreza Jahangir Moghadam Jan 2012

Infrared Imaging Method For Thermographic Characterizing Of Medical High Intensity Focused Ultrasound Devices, Mohammadreza Jahangir Moghadam

Electrical Engineering Theses - Archive

With new improvements in high-end commercial R&D Infrared camera technologies many challenges have been overcome for exploring high speed Infrared imaging, the ability to capture fast varying phenomena without image blur, acquire enough data to properly characterize dynamic energy, and increase the dynamic range without compromising the number of frames per second. This study presents a noninvasive method for determining the spatial and thermal heating profiles in a phantom tissue generated by High Intensity Focused Ultrasound (HIFU) beam by using Infrared imaging. A high speed Infrared camera was placed above a tissue mimicking material that was heated at the focal …

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Time Invariant Modeling Of Higher Order Dc-Dc Converters, Lei Niu Jan 2012

Time Invariant Modeling Of Higher Order Dc-Dc Converters, Lei Niu

Electrical Engineering Theses - Archive

A time invariant modeling technique is proposed for higher order dc-dc converters, including Cuk, SEPIC, and Zeta converters. This thesis also investigates some issues involved in applying existing averaging techniques such as circuit averaging, state space averaging, generalized state space averaging, Krylov-Bogoliubov-Mitropolsky method, and Floquet theory, to model the dynamic behaviors of higher order converters. The proposed methodology is shown to provide better accuracy compared to existing techniques, and distinguishes between different types of carrier signals of modulation, for instance, sawtooth and isosceles triangle carrier signal. This thesis offers a straightforward systematic procedure and summarizes this procedure with a list …

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Design And Printed Circuit Board Level Implementation Of A Narrow Band Lc Vco, Anjan Govindaraju Jan 2012

Design And Printed Circuit Board Level Implementation Of A Narrow Band Lc Vco, Anjan Govindaraju

Electrical Engineering Theses - Archive

A Voltage Controlled Oscillator (VCO) using a 0.6 µm CMOS technology has been designed and fabricated. The design's tuning range is from 390 MHz to 410 MHz, with the center frequency being 400 MHz. The oscillator is powered by a 2.5 volt power supply. The controlling voltage varies from 0.87 to 1.6 volts. Simulation of the LC VCO was carried out in the Advanced Design System (ADS) program. For the printed circuit board level implementation, the layout was first performed using the ADS program, and then its image was transferred on to a printed circuit board. The device footprints were …

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A Real-Time Embedded Fpga Interface For An Ethernet Based Line Laser, Subrahmanya Ramaswamy Jan 2012

A Real-Time Embedded Fpga Interface For An Ethernet Based Line Laser, Subrahmanya Ramaswamy

Electrical Engineering Theses - Archive

Profile measurement systems developed at the Transportation Instrumentation and Embedded systems Lab (TIL) at the University of Texas at Arlington are used by Texas Department of Transportation (TxDOT) to compute the profile of the road. The systems use certain basic sensors such as a laser, start sensor, distance encoder and accelerometer. The data samples from these sensors are acquired and stored for further processing. The data is processed in real-time using a road profiling algorithm to calculate the profile. This research effort investigates the feasibility of implementing the existing system using FPGA components and specifically for interfacing the laser to …

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Modeling And Identification Of Thermally Actuated Micro-Robots, Sai Kalyan Yelike Jan 2012

Modeling And Identification Of Thermally Actuated Micro-Robots, Sai Kalyan Yelike

Electrical Engineering Theses - Archive

This thesis explains the system identification of thermally actuated micro-robots and actuators developed at UTA-NGS (Next Generation Systems) and ARRI (Automation Robotics Research Institute). The energy used to power these actuators are externally-supplied voltage and class IV Laser sources. The micro-robots actuated with class IV laser sources have displacements recorded through a camera. Applied laser input waveforms and micro-robot's positional displacement are used for system identification of the Micro-robot. Various system identification methods (non-recursive and recursive) are used for creating a mathematical model of the physical system (Micro-robot). A similar approach is followed for micro-actuators known as chevron actuators powered …

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Implementation And Analysis Of Directional Discrete Cosine Transform In H.264 For Baseline Profile, Shreyanka Subbarayappa Jan 2012

Implementation And Analysis Of Directional Discrete Cosine Transform In H.264 For Baseline Profile, Shreyanka Subbarayappa

Electrical Engineering Theses - Archive

H.264/AVC [1] is a video coding standard that has 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 the coder. 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 of the signal/image is concentrated in a fewer number of coefficients. Thus the insignificant coefficients can be discarded after transform coding to achieve …

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Performance Analysis And Implementation Of Mode Dependent Dct/Dst In H.264/Avc, Priyadarshini Anjanappa Jan 2012

Performance Analysis And Implementation Of Mode Dependent Dct/Dst In H.264/Avc, Priyadarshini Anjanappa

Electrical Engineering Theses - Archive

Video communications require significant amounts of information transmission. Video compression involves the bitrate reduction of a digital video signal carrying visual information. Compression can be a lossless or a lossy operation. Because of the immense volume of video information, lossy operations are mainly used for video compression. H.264 is a video compression standard that defines a wide set of coding tools to achieve compression. Transform coding is a lossy compression technique that exploits statistical dependencies between image pixels by converting them into coefficients with little or no dependencies. Block transform coding is widely used in image and video compression systems, …

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Silicon Defect Recognition, Aditi S. Godbole Jan 2012

Silicon Defect Recognition, Aditi S. Godbole

Electrical Engineering Theses - Archive

An algorithm is presented for the recognition of four types of defects present in silicon wafer images. Defect recognition is achieved by following a 3-step process: segmentation, feature extraction and classification.Multiple image segmentation algorithms are tried for locating and isolating the defects present in the silicon wafer images. The proposed image segmentation technique is based on simple concept of threshold based segmentation and edge detection based segmentation. Combination of four segmentation algorithms based on above mentioned techniques are used such that each segmentation algorithm specializes in segmenting a certain type of defect, thereby ensuring high chances of correct segmentation. Out …

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Super-Resolution With Better Edge Enhancement, Gaurav Hansda Jan 2012

Super-Resolution With Better Edge Enhancement, Gaurav Hansda

Electrical Engineering Theses - Archive

Super resolution image reconstruction is a promising technique of digital imaging which attempts to generate a raster image with a higher resolution than its source. The source can consist of one or more images or frames. This thesis focuses on single-frame super-resolution i.e. the source is a single raster image. Changing the resolution directly refers to resampling the image. Specific algorithms have been designed for scaling up, scaling down and rotating images that deliver high quality results. Process of scaling up or super-resolution is the primary focus of this thesis, which in contrast scaling down or rotating deals with the …

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Interference Mitigation In 4g Lte-A Heterogenous Networks, Rohan Nag Kummithe Jan 2012

Interference Mitigation In 4g Lte-A Heterogenous Networks, Rohan Nag Kummithe

Electrical Engineering Theses - Archive

Long Term Evolution (LTE) complements 3G networks with high data rates, low latency and a flat, IP-based architecture. It also allows operators to use a new and a much wider spectrum when compared to the previous standards. To further enhance this and to achieve the constraints set by the International Mobile Telecommunication-Union (IMT-U), 3GPP has been working on various aspects of the LTE-Advance standard which has been officially termed as 4G network.Apart from the enhancements in the radio link, the next performance leap in wireless networks will come from an evolved network topology. The concept is to improve spectral efficiency …

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Analytical Evaluation Of Frequency Reuse For Ofdma Cellular Networks, Anis Davoudi Jan 2012

Analytical Evaluation Of Frequency Reuse For Ofdma Cellular Networks, Anis Davoudi

Electrical Engineering Theses - Archive

In this thesis, the goal is to arrive at tractable general expressions for probability of coverage and achievable rate for a typical mobile user. For this purpose, the grid network model is replaced with the Poisson Point Process model. Later, the scenario has been made narrower and then, it is assumed that the power of the interference signals has exponential distribution, which has helped to greatly simplify the formulas. Then, to evaluate the effect of frequency reuse on the probability of coverage and the average achievable rate in the new model, these results have been simulated. Frequency reuse had a …

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Circuit Pools: Preventive Information Leak Attacks In Salsa Through Cached Lookups, Anahita Davoudi Jan 2012

Circuit Pools: Preventive Information Leak Attacks In Salsa Through Cached Lookups, Anahita Davoudi

Electrical Engineering Theses - Archive

An improvement in preventing information leak attacks has been proposed by enhancing the path building process using pair of nodes obtained from lookups done by each initiator randomly. Using a pool of pairs locally produced for each initiator by random lookups done by that node; improves anonymity for the circuit initiator. The percentages of how many pools each pair belongs to, availability of each pair, and number of circuit attempts are analyzed for different number of both pool size and redundancy level. With these modifications and additions, the performance of the system has improved against the Conventional Continuous Stage Attack, …

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Development Of Gelatin Microbubble Based Plga Scaffold For Application In Bone Tissue Engineering, Krishna M. Shah Jan 2012

Development Of Gelatin Microbubble Based Plga Scaffold For Application In Bone Tissue Engineering, Krishna M. Shah

Bioengineering Theses - Archive

The overall goal of the study was to develop a delivery system for a potential bone tissue engineering application focusing on fabrication of gelatin microbubble (MB) based PLGA scaffolds capable of recruiting Mesenchymal stem cells (MSCs) and delivering bioactive molecules. Challenges associated with inefficient use of stem cells, scaffolding techniques and poor understanding of the role of growth factors hinders the success of tissue engineering strategies. A major challenge with the use of autologous stem cells is its low proliferation and migratory capacity. Our lab previously established that using a biomaterial implant, autologous MSCs can be directed and recruited in …

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New Detonation Concepts For Propulsion And Power Generation, Eric Braun Jan 2012

New Detonation Concepts For Propulsion And Power Generation, Eric Braun

Mechanical and Aerospace Engineering Dissertations - Archive

A series of related analytical and experimental studies are focused on utilizing detonations for emerging propulsion and power generation devices. An understanding of the physical and thermodynamic processes for this unsteady thermodynamic cycle has taken over 100 years to develop. An overview of the thermodynamic processes and development history is provided.Thermodynamic cycle analysis of detonation-based systems has often been studied using surrogate models. A real gas model is used for a thermal efficiency prediction of a detonation wave based on the work and heat specified by process path diagrams and a control volume analysis. A combined first and second law …

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Hygrothermally Stable Laminated Composites For Optimal Extension Twist Coupling In Closed Cell Configuration, Sean Muder Jan 2012

Hygrothermally Stable Laminated Composites For Optimal Extension Twist Coupling In Closed Cell Configuration, Sean Muder

Mechanical and Aerospace Engineering Theses - Archive

An optimization routine utilizing the sequential quadratic programming method is used to develop laminates that are hygrothermally stable in flat-strip configuration and are optimal for extension twist coupling in closed cell configuration. The performance of the laminates obtained from the optimization in terms of the level of extension twist coupling and hygrothermal stability are evaluated and compared to laminates from a previous routine. A parametric study is conducted to illustrate the relationships between the geometric dimensions of a representative closed cell section and the level of extension twist coupling. Results from the parametric study suggested a more practical optimization approach …

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Dynamic System Reduction And Fault Location Identification Using Synchrophasors, Eithar Nashawati Jan 2012

Dynamic System Reduction And Fault Location Identification Using Synchrophasors, Eithar Nashawati

Electrical Engineering Dissertations - Archive

The advent of the synchronized phasor measurement units' technology allow for new applications to the power systems and improvement of existing applications. This dissertation presents a new method for synchrophasor-assisted fault location. An initial screening of voltage phase angle swing determines the suspect part of the system where the disturbance occurred. The system is then reduced to a limited number of buses. A Positive-sequence voltage-only method is then used to provide a better estimation of the exact location of the fault using particle swarm optimization. This method is applied to a large power system in North Texas. Real-time synchrophasor measurement …

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Multi-Directional Light Coupling Structures For Nanomembrane Photonic Integration, Tapas Kumar Saha Jan 2012

Multi-Directional Light Coupling Structures For Nanomembrane Photonic Integration, Tapas Kumar Saha

Electrical Engineering Dissertations - Archive

Vertical coupling of light within an in-plane nanophotonic waveguide is an essential step towards the successful future realization of CMOS compatible optical interconnects and photonic integrated circuits. This is especially important, since silicon, though being the material of choice, is an extremely poor emitter of light. Through vertical to in-plane coupling, light can be coupled through any point on the planar on chip and the position is not only confined within the edges of the silicon wafer. Compact wafer scale testing is possible with this approach, without the need for polished edge cleaving. Another important aspect of this research is …

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Accelerated Simulation Of Supercapacitors Using Order Reduction Techniques And Waveform Relaxation Methods, Fatih Cingoz Jan 2012

Accelerated Simulation Of Supercapacitors Using Order Reduction Techniques And Waveform Relaxation Methods, Fatih Cingoz

Electrical Engineering Theses - Archive

Supercapacitors are promising energy storage devices due to their capability to deliver high peak current and to capture a huge amount of energy in a short time with very low internal power loss. They are candidate component to be used in as a secondary energy storage device in hybrid electric vehicles (HEV)). Precise model development and accelerated simulation environments are needed to minimize the design time (and subsequently the product-to-market time) and minimize the hardware redesign and retrofit. Transmission line and RC parallel-branch equivalent models show relatively higher accuracy in predicting the dynamic behavior of the device. They also have …

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Characterization Of Flexible Antennas For Wirelessly Powering Medical Implants, Safwan Ahmed Muneer Jan 2012

Characterization Of Flexible Antennas For Wirelessly Powering Medical Implants, Safwan Ahmed Muneer

Electrical Engineering Theses - Archive

To minimize the trouble experienced by the patient in undergoing invasive surgeries to replace non rechargeable batteries that are used to power body implants inside, medical experts and engineers are emphasizing on making use of wireless power. Since body implant powering from external wireless power requires a source that can be easily worn outside the body, a special type of integrated antenna was implemented on a flexible substrate that conforms to the shape of the stomach curvature, thus adding increased patient comfort. The antenna bend is concave which adds to increased focus and increases power transfer efficiency to power the …

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Complexity Reduction Of H.264 Using Parallel Programming, Sudeep Prakash Gangavati Jan 2012

Complexity Reduction Of H.264 Using Parallel Programming, Sudeep Prakash Gangavati

Electrical Engineering Theses - Archive

The H.264 encoder provides for adaptive directional intra-prediction, motion-compensated inter-prediction followed by transform, quantization, deblocking filtering and either variable length encoding or arithmetic coding. All these blocks of the H.264 encoder make it highly complex as compared to previous video coding standards. There is a need for measures to reduce the complexity. This thesis aims at reducing the complexity of the .H.264 encoder by reducing the encoding time of the H.264 standard while not sacrificing the video quality, compression efficiency and bitrate by parallel programming. There are several parallel programming models that can be used. The massively parallel Graphics Processing …

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Design, Microfabrication And Characterization Of A Microheater Platform For Studying Dna-Surface Interactions, Annas Javed Jan 2012

Design, Microfabrication And Characterization Of A Microheater Platform For Studying Dna-Surface Interactions, Annas Javed

Electrical Engineering Theses - Archive

The past few decades have witnessed significant research towards developing DNA biosensors and gene chips. These devices obtain sequence-specific DNA information in a faster, simpler and cheaper manner compared to traditional hybridization assays. Miniaturization of DNA handling and processing devices has contributed significantly towards this effort. Despite the large amount of work in this research direction, much more needs to be understood about the fundamental interactions of DNA and other biological macromolecules with their microenvironment, particularly with inorganic surfaces. For example, a basic understanding of thermal interactions of DNA with surfaces may help develop novel strategies for probing, purifying and …

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Design Of Embedded Nios Ii Processor Based System For Implementing Bridging Algorithm Of Profiling Application, Vinay S. Ashi Jan 2012

Design Of Embedded Nios Ii Processor Based System For Implementing Bridging Algorithm Of Profiling Application, Vinay S. Ashi

Electrical Engineering Theses - Archive

The Texas Department of Transportation (TxDOT) uses multiple instruments for quality assurance of new and existing pavements. These instruments measure the different characteristics of the pavement such as the longitudinal profile, transverse profile, texture, rutting, etc. to determine the smoothness and ride quality of the pavement. These instruments mainly consist of different sensors such as lasers, accelerometers, distance encoders, etc., to calculate the ride quality. Various ride statistics such as International Roughness Index (IRI), Mean Profile Depth (MPD), and Present Serviceability Index (PSI) are then calculated and used to monitor the conditions of the roads.The Roline laser system is used …

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Development Of Magnetic-Based Multi-Layer Microparticles For Stem Cell Isolation, Enrichment And Detachment, Sonia Santimano Jan 2012

Development Of Magnetic-Based Multi-Layer Microparticles For Stem Cell Isolation, Enrichment And Detachment, Sonia Santimano

Bioengineering Theses - Archive

Stem cells have been studied and used in several cell-based therapies for regenerative medicine, 3D tissue-engineered scaffolds, and in vitro models for drug screening and testing. For instance, cell based therapy via the use of stem cells like Endothelial Progenitor Cells (EPCs) to treat patients with cardiovascular diseases, including ischemic heart disease, in-stent restenosis, and peripheral arterial occlusive disease. In addition, Circulating Cancer Cells (CSCs) have been used as an indication of cancer progression-free survival and for studying the mechanisms of tumor formation, metastasis, and anti-cancer drug screening. Due to their extensive diagnostic and therapeutic potential, various techniques have been …

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Quantification And Comparisons Of Motion Metrics For Finger Tapping Performed By Children With Cerebral Palsy Before And After Therapy With Two Motion Tracking Camera Systems, Ankita H. Chainani Jan 2012

Quantification And Comparisons Of Motion Metrics For Finger Tapping Performed By Children With Cerebral Palsy Before And After Therapy With Two Motion Tracking Camera Systems, Ankita H. Chainani

Bioengineering Theses - Archive

The quantification of any improvements in the use of a paretic arm after children with cerebral palsy (CP) undergo rehabilitation is currently done by occupational therapists who administer a series of manual ability tests and assign a subjective score for each test task performed. In this work the hypothesis was explored of whether quantification of hand motion metrics by motion tracking while children with CP performed a hand tapping task could be used as a more quantitative surrogate for assessing how well these children control the use of their hand. To that end, two children with CP, both classified as …

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Spectrophotometric Quantification Of Bilirubin In Sclera Of The Eye Using Visible Dlp® Hyperspectral Imaging, Naveen Balaji Balasubramanian Jan 2012

Spectrophotometric Quantification Of Bilirubin In Sclera Of The Eye Using Visible Dlp® Hyperspectral Imaging, Naveen Balaji Balasubramanian

Bioengineering Theses - Archive

In clinical settings doctors strive to give best care to the patients by looking for methods to diagnose the illness early to intervene with the necessary treatment. In the case of patients with liver problems (e.g. cirrhosis, hepatitis) an early indicator of impaired liver function is an increased concentration of bilirubin in the blood circulation. Bilirubin concentration is currently quantified by blood sampling, which is invasive, and it would be desirable to have a technology that quantifies bilirubin non-invasively. The goal of this work was to help address this clinical need and develop a methodology for determining non-invasively a measure …

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Antimicrobial Properties Of Citric Acid Based Polymers, Lee-Chun Su Jan 2012

Antimicrobial Properties Of Citric Acid Based Polymers, Lee-Chun Su

Bioengineering Theses - Archive

A series of citric acid derived polymers synthesized in our lab were investigated and compared for their physiochemical and antimicrobial properties. We selected citric acid based polymers since citric acid is a product of natural metabolism. These polymers are not only biocompatible but also possess an antimicrobial effect. In polymer synthesis, citric acid (CA) provides profound functional groups available for binding and crosslinking to allow the controllable crosslinking degrees of polymers. A number of citric acid based polymers has been synthesized and studied for their chemical, mechanical, and biological characteristics for use in various biomedical applications. Since bacterial infections became …

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Regenerative Peripheral Nerve Interfacing Of Sensory Modalities, Nilanjana T. Dutta Jan 2012

Regenerative Peripheral Nerve Interfacing Of Sensory Modalities, Nilanjana T. Dutta

Bioengineering Theses - Archive

Peripheral neural interfaces (PNI) has proved potential to record motor commands for the control of these prosthetic limbs, together with stimulation of specific sensory axons, so as to transmit specific sensory sub-modalities. Although PNI is hypothesized to provide adequate sensory feedback, realizing this degree of specificity is not fully established. Recently, a regenerative multi-electrode interface (REMI) was reported to be capable of recording peripheral nerve activity from a transected nerve. This study is aimed at interfacing neural activity specific to sensory sub-modalities, such as thermal pain, mechanoception and limb stretching using the REMI, in a freely moving animal. In the …

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Characterization Of Immune Response And Peripheral Nerve Regeneration Of Implanted Regenerative Multi-Electrode Interface Post-Subchronic Amputation, Camilo Andres Sanchez Useche Jan 2012

Characterization Of Immune Response And Peripheral Nerve Regeneration Of Implanted Regenerative Multi-Electrode Interface Post-Subchronic Amputation, Camilo Andres Sanchez Useche

Bioengineering Theses - Archive

Interfacing high degree-of-freedom robotic prosthetics directly to the peripheral nervous system aims at improving the quotidian life of amputees. Despite advancements in robotics that have lead to human-like upper limb prosthetics, long-term interfacing has not been accomplished, thus voiding them from clinical use. Interfacing electrodes in the central nervous system fail due to the foreign body reaction and glial scar formation at the site of implantation. Concrete mechanisms for the failure of long-term Interfacing at the peripheral nervous level remain unclear. A regenerative multi-electrode interface (REMI) which allows for action potential recording as early as 7 days and provides support …

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Development Of A Measurement System For Quantifying Ultrasound Field Distribution Of Different Transducers, Jayanth Kandukuri Jan 2012

Development Of A Measurement System For Quantifying Ultrasound Field Distribution Of Different Transducers, Jayanth Kandukuri

Bioengineering Theses - Archive

Ultrasound has been widely used in many fields, such as nondestructive examination and medical imaging. Ultrasound is mostly characterized by its pressure and, dynamic pressure wave can be considered to be the foundation of ultrasound physics and imaging techniques. It is thus important for understanding ultrasound pressure properties to that of ultrasound intensity. Moreover, there are many applications that require mainly characterizing ultrasound pressure field (instead of intensity field alone). Therefore, reconstruction of an ultrasound pressure field is highly desirable not only for education but also for research. There may be some commercially available systems that can be used for …

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Using An Ahp/Anp Hybrid Methodology For Freight Transport Networks Selection Towards Sustainable Transportation, Andrea M. Graham Jan 2012

Using An Ahp/Anp Hybrid Methodology For Freight Transport Networks Selection Towards Sustainable Transportation, Andrea M. Graham

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

The selection of an effective transportation network for the transport of container freight is one of the most important factors in supply chain and logistics planning. The current transport networks, hub-and-spoke and point-to-point, although optimal in many aspects are still plagued with issues in route optimization, empty travel, and bad intermodal synchronization. The trucking industry, the most utilized of all modes, offers unsustainable components in its current state that continually introduce negative impacts to an ever evolving supply chain network. This research investigates a third potentially more sustainable distributed multi-segment transportation network. This network will be compared to the traditional …

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