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2004

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Articles 1 - 30 of 2982

Full-Text Articles in Engineering

Emisja Chlorowodoru Ze Spalania Węgla W Kotle Pyłowym, Marian Mazur, Robert Oleniacz, Przemysław Szczygłowski, Marek Bogacki Dec 2004

Emisja Chlorowodoru Ze Spalania Węgla W Kotle Pyłowym, Marian Mazur, Robert Oleniacz, Przemysław Szczygłowski, Marek Bogacki

Robert Oleniacz

Emission of hydrogen chloride (HCl) from coal combustion is not controlled just like for example sulpfur dioxide emission. But HCl emission is also important, because chlorine content in some types of coal can reach the similar level to sulfur content. In the paper the measurement results of HCl emission to the air during combustion of three types of coal with law content of chlorine were presented. The researches were carried out for a steam pulverized coal boiler (max. boiler efficiency – 430 t/h) during three various loads (respectively 65, 80 and 95 % of maximum efficiency) without flue gas desulfurization. The ...


Behavior Of Structural Concrete Members Strengthened By Composite Fabrics, Jian Chen Dec 2004

Behavior Of Structural Concrete Members Strengthened By Composite Fabrics, Jian Chen

Dissertations

The new technique of using Fiber Reinforced Polymer (FRP) materials to repair and strengthen various concrete members is becoming more and more popular in structural retrofitting field. Among all the confining materials, Carbon Fiber Reinforced Polymer (CFRP) fabric jackets are identified as an effective way to enhance the strength and ductility of concrete members due to its superior mechanical properties. This study investigates the detailed structural behavior of confined concrete members using CFRP fabric jackets by both analytical and experimental approaches.

A series of CFRP wrapped concrete cylinder tests were conducted to study the compressive stress-strain behavior for CFRP confined ...


Qos Constrained Cellular Ad Hoc Augmented Networks, Chi-Tung Chen Dec 2004

Qos Constrained Cellular Ad Hoc Augmented Networks, Chi-Tung Chen

Dissertations

In this dissertation, based on different design criteria, three novel quality of service (QoS) constrained cellular ad hoc augmented network (CAHAN) architectures are proposed for next generation wireless networks. The CAHAN architectures have a hybrid architecture, in which each MT of CDMA cellular networks has ad hoc communication capability. The CAHAN architectures are an evolutionary approach to conventional cellular networks. The proposed architectures have good system scalability and high system reliability.

The first proposed architecture is the QoS constrained minimum-power cellular ad hoc augmented network architecture (QCMP CAHAN). The QCMP CAHAN can find the optimal minimum-power routes under the QoS ...


Tide-Influenced Contaminant Transport In Coastal Aquifers, Yong Peng Dec 2004

Tide-Influenced Contaminant Transport In Coastal Aquifers, Yong Peng

Dissertations

Coastal aquifers are distinguished from other aquifers because of tidal effects which cause complicated groundwater flow and contaminant transport phenomena in regions immediately adjacent to the coast. This study is designed to address the significance of tidal influence on contaminant transport by focusing on one-dimensional homogeneous coastal aquifers.

This study formulates a conceptual model and corresponding flow and transport equations, analyzes coastal boundary conditions, solves numerically the transport equation, and uses experiments to verify the numerical results.

Results of numerical and experimental studies conclude that tides can have a significant impact on contaminant transport, especially when under unconfined conditions, subject ...


Computational Studies Of Viscoelastic Multiphase Flows, Shriram B. Pillapakkam Dec 2004

Computational Studies Of Viscoelastic Multiphase Flows, Shriram B. Pillapakkam

Dissertations

A finite element code based on the level set method is developed for performing two and three dimensional direct numerical simulations (DNS) of viscoelastic two-phase flow problems. The Oldroyd-B constitutive equation is used to model the viscoelastic liquid. The code is used to study transient and steady state shapes of Newtonian and viscoelastic drops in simple shear and buoyancy driven flows. The roles of the governing dimensionless parameters: Capillary number (Ca), Deborah Number (De) and the polymer concentration parameter c, in determining deformation of drops and bubbles, are also analyzed.

The numerical code permits us to vary Ca, De and ...


Crystalization Studies In Hollow Fiber Devices, Dimitrios Zarkadas Dec 2004

Crystalization Studies In Hollow Fiber Devices, Dimitrios Zarkadas

Dissertations

Crystallization was examined under a new perspective and in a flow environment much different from that available in currently used industrial devices. Three crystallization techniques were tested in the unique flow environment offered by hollow fiber devices. In addition, a new type of heat exchanger based on hollow fibers was tested as well as the potential use of porous hollow fiber devices as mixing devices. Hollow fiber devices are compact, extremely efficient on a volumetric basis, easy to scale up and control and their inherent characteristics promote the creation of homogeneous temperature and concentration conditions on a scale considerably smaller ...


Turbo Space-Time Coding For Mimo Systems : Designs And Analyses, Hangjun Chen Dec 2004

Turbo Space-Time Coding For Mimo Systems : Designs And Analyses, Hangjun Chen

Dissertations

Multiple input multiple output (MIMO) systems can provide high diversity, high data rate or a mix of both, for wireless communications. This dissertation combines both modes and suggests analyses and techniques that advance the state of the art of MIMO systems. Specifically, this dissertation studies turbo space-time coding schemes for MIMO systems.

Before the designs of turbo space-time codes are presented, a fundamental tool to analyze and design turbo coding schemes, the extrinsic information transfer (EXIT) chart method, is extended from the binary/nonbinary code case to coded modulation case. This extension prepares the convergence analysis for turbo space-time code ...


The Feasibility Of Micromachined Dynamic Resonant Beam Coriolis True Mass Flow Meter, Sang Hwui Lee Dec 2004

The Feasibility Of Micromachined Dynamic Resonant Beam Coriolis True Mass Flow Meter, Sang Hwui Lee

Dissertations

The technological advances of micro-electro-mechanical systems (MEMS) in the past two decades have been remarkable for innovations in microfluidic systems as well as automotive applications such as pressure sensors and accelerometers. MEMS flow sensing has emerged as a field of interest in microfluidics, with a variety of sensing methods being miniaturized, such as thermal anemometry, ultrasonic sensing and flow measurement based on the Coriolis effect. Coriolis sensing is particularly attractive since, unlike most other methods which provide volumetric flow information, Coriolis sensing is capable of providing a direct, true mass flow measurement. Because of this advantage, Coriolis flow sensing has ...


Detection Of Network Anomalies And Novel Attacks In The Internet Via Statistical Network Traffic Separation And Normality Prediction, Jun Jiang Dec 2004

Detection Of Network Anomalies And Novel Attacks In The Internet Via Statistical Network Traffic Separation And Normality Prediction, Jun Jiang

Dissertations

With the advent and the explosive growth of the global Internet and the electronic commerce environment, adaptive/automatic network and service anomaly detection is fast gaining critical research and practical importance. If the next generation of network technology is to operate beyond the levels of current networks, it will require a set of well-designed tools for its management that will provide the capability of dynamically and reliably identifying network anomalies. Early detection of network anomalies and performance degradations is a key to rapid fault recovery and robust networking, and has been receiving increasing attention lately.

In this dissertation we present ...


Three-Dimensional Shape Characterization For Particle Aggregates Using Multiple Projective Representations, Jonathan Paul Corriveau Dec 2004

Three-Dimensional Shape Characterization For Particle Aggregates Using Multiple Projective Representations, Jonathan Paul Corriveau

Theses and Dissertations

Shape descriptors are used extensively in computer vision/automated recognition applications such as fingerprint matching, robotics, character recognition, etc. The conventional two-dimensional shape descriptors used in these applications do not readily lend themselves to compact representations in three dimensions. The situation is even more challenging when one attempts to numerically describe the three-dimensional shapes of a mixture of objects such as in an aggregate mix.

The goal of this study is the design, development and validation of automated image processing algorithms that can estimate three-dimensional shape-descriptors for particle aggregates. The thesis demonstrates that a single set of numbers representing a ...


Cyclic Prefix Assisted Block Transmission For Low Complexity Communication System Design, Haibin Huang Dec 2004

Cyclic Prefix Assisted Block Transmission For Low Complexity Communication System Design, Haibin Huang

Theses

This thesis presents new results on cyclic prefix (CP) assisted block transmission for low complexity communication system design. Two important aspects are studied: the CP based low-complexity schemes for channel equalization and channel estimation.

Specifically, based on the simple frequency domain equalization, a low complexity joint receiver is proposed for CP-CDMA system, which is a special application of block transmission.

And in this work the finite impulse response (FIR) model is used for the unknown communication channels. To identify an unknown FIR channel, a novel channel estimation method is proposed by exploiting the cyclic prefix technique. Compared to a conventional ...


Vlsi Implementation Of An Efficient Method For The Computation Of Line Spectral Frequencies, David L. Reynolds Dec 2004

Vlsi Implementation Of An Efficient Method For The Computation Of Line Spectral Frequencies, David L. Reynolds

Theses and Dissertations

In speech coding applications using linear predictive techniques, the computation of line spectral frequencies (LSFs) from the predictor coefficients is an extremely computationally intensive task. The unique properties of the symmetric and antisymmetric polynomial roots limit the region which must be searched, however it is still necessary to perform a root-finding algorithm on a high-order polynomial.

Certain algorithms have been developed to reduce the complexity of the root finding exercise. One such algorithm, developed by Ramachandran and Kabal, takes advantage of certain properties of the symmetric and antisymmetric polynomials to map the upper portion of the unit circle onto the ...


Heterogeneous Multi-Sensor Data Fusion Using Geometric Transformations And Parzen Windows For The Nondestructive Evaluation Of Gas Transmission Pipelines, Joseph Anthony Oagaro Dec 2004

Heterogeneous Multi-Sensor Data Fusion Using Geometric Transformations And Parzen Windows For The Nondestructive Evaluation Of Gas Transmission Pipelines, Joseph Anthony Oagaro

Theses and Dissertations

The natural gas transmission pipeline network in the United States is a key component of the nation's energy supply infrastructure and extends for over 280,000 miles and has an average age of over 60 years. The integrity of the pipeline is maintained by periodic inline inspections using magnetic or ultrasonic pigs. Defect characterization algorithms developed using current pigging data are hampered by the fact that single inspection techniques (either magnetic or ultrasonic) do not yield sufficient information for accurately and repeatably characterizing defects. This thesis demonstrates that defect characterization algorithms using multiple inspection techniques can accomplish this task ...


Experimental Technique For Studying High-Temperature Phase Equilibria In Reactive Molten Metal Based Systems, Alexandre Ermoline Dec 2004

Experimental Technique For Studying High-Temperature Phase Equilibria In Reactive Molten Metal Based Systems, Alexandre Ermoline

Dissertations

The general objective of this work is to develop an experimental technique for studying the high-temperature phase compositions and phase equilibria in molten metal-based binary and ternary systems, such as Zr-O-N, B-N-O, Al-O, and others. A specific material system of Zr-O-N was selected for studying and testing this technique.

The information about the high-temperature phase equilibria in reactive metal-based systems is scarce and their studying is difficult because of chemical reactions occurring between samples and essentially any container materials, and causing contamination of the system.

Containerless microgravity experiments for studying equilibria in molten metal-gas systems were designed to be conducted ...


Corrosion Studies On Alpha Tantalum And Beta Tantalum Coated Steel, Sung Min Maeng Dec 2004

Corrosion Studies On Alpha Tantalum And Beta Tantalum Coated Steel, Sung Min Maeng

Dissertations

Tantalum coating by sputtering, one form of physical vapor deposition (PVD), has been investigated as a replacement for chromium coatings on gun bores to protect them from erosion and corrosion due to its high ductility and high corrosion resistance in aggressive environments. When deposited as a film on steel substrates by sputtering, either α-Ta, β-Ta, or a mixture of both phases have been observed under varying deposition conditions. To evaluate corrosion behavior of Ta coatings, electrochemical impedance spectroscopy and potentiodynamic polarization were conducted as a function of coating thickness. The coating porosity was observed to decrease with increasing coating thickness ...


Uniaxial And Triaxial Behavior Of High Strength Concrete With And Without Steel Fibers, Xiaobin Lu Dec 2004

Uniaxial And Triaxial Behavior Of High Strength Concrete With And Without Steel Fibers, Xiaobin Lu

Dissertations

This study first presents an extensive experimental research program on the true uniaxial and triaxial compression behavior for both high strength concrete (HSC) and steel fiber reinforced high strength concrete (SFHSC). The experimental study mainly focuses on the octahedral shear stress strain relationship of those two types of concrete, which is adopted as the basis to develop a new incremental constitutive model. Emphasis is also put on the investigation of the variation of tangent Poisson's ratio under not only uniaxial but also triaxial stress conditions. The effect of cyclic loading on this parameter is also addressed.

According to this ...


High Temperature Heat Exchanger Project: Quarterly Progress Report October 1, 2004 Through December 31, 2004, Anthony Hechanova Dec 2004

High Temperature Heat Exchanger Project: Quarterly Progress Report October 1, 2004 Through December 31, 2004, Anthony Hechanova

Publications (NSTD)

UNLV hosted an NHI Systems Interface Meeting on Dec. 16 and a UNLVRF HTHX Kickoff Meeting on Dec. 17. The purpose of the meetings was to coordinate the FY05 research and development effort of the UNLV Research Foundation portion of the Nuclear Hydrogen Initiative among the DOE, national program technical directors and the UNLVRF collaborators. Collaborators also had the opportunity to discuss their research program plan and update their progress. It was decided that these type of collaboration meetings were very useful and they will be held quarterly at the various collaborator sites. The next meeting will be in March ...


Theoretical Modeling Of Protective Oxide Layer Growth In Non-Isothermal Lead-Alloys Coolant Systems, Yitung Chen Dec 2004

Theoretical Modeling Of Protective Oxide Layer Growth In Non-Isothermal Lead-Alloys Coolant Systems, Yitung Chen

Transmutation Sciences Materials (TRP)

The goal of the proposed research project is to provide basic understanding of the protective oxide layer behaviors and to develop oxide layer growth models of steels in non-isothermal lead-alloys (lead or lead-bismuth eutectic) coolant systems. It is widely recognized that the corrosiveness of the lead-alloys is a critical obstacle and challenge for which it can be safely used or applied in the nuclear coolant systems. Active oxygen control technique can promote the formation of the “self-healing” oxide films on the structural material surface, drastically reducing steel corrosion and coolant contamination. Many experiments of steels exposed to flowing lead-alloys have ...


Development Of Integrated Process Simulation System Model For Spent Fuel Treatment Facility (Sftf) Design: Quarterly Report October 1-December 31, 2004, Yitung Chen, Sean Hsieh Dec 2004

Development Of Integrated Process Simulation System Model For Spent Fuel Treatment Facility (Sftf) Design: Quarterly Report October 1-December 31, 2004, Yitung Chen, Sean Hsieh

Separations Campaign (TRP)

The Advanced Fuel Cycle Initiative (AFCI) and Transmutation Research Program- University Participation Program (TRP-UPP) supported by Department of Energy of the United States have been developing many important technologies for the transmutation of nuclear waste to address long-term disposal issues. While successfully embedding AMUSE module into a dedicated System Engineering Model (TRPSEMPro), developed by the Nevada Center for Advanced Computational Methods (NCACM) at the University of Nevada, Las Vegas collaborating with Argonne National Laboratory (ANL), ANL is interested in further simulating the Light Water Reactor (LWR) Spent Fuel Treatment Facility (SFTF) combining commercial process simulation and analysis packages and core ...


A Digital Signature And Watermarking Based Authentication System For Jpeg2000 Images, Rui Jing Dec 2004

A Digital Signature And Watermarking Based Authentication System For Jpeg2000 Images, Rui Jing

Theses

In this thesis, digital signature based authentication system was introduced, which is able to protect JPEG2000 images in different flavors, including fragile authentication and semi-fragile authentication. The fragile authentication is to protect the image at code-stream level, and the semi-fragile is to protect the image at the content level.

The semi-fragile can be further classified into lossy and lossless authentication. With lossless authentication, the original image can be recovered after verification. The lossless authentication and the new image compression standard, JPEG2000 is mainly discussed in this thesis.


An Investigation Of Multi-Dimensional Evolutionary Algorithms For Virtual Reality Scenario Development, Scott Papson Dec 2004

An Investigation Of Multi-Dimensional Evolutionary Algorithms For Virtual Reality Scenario Development, Scott Papson

Theses and Dissertations

Virtual reality (VR) has emerged as a powerful visualization tool for design, simulation, and analysis in modem complex industrial systems. The primary motivation for this thesis is to develop a framework for the effective use of VR in design-simulation-analysis cycles, particularly in situations involving large, complex, multi-dimensional data-sets. This thesis develops a framework that is intended to support not only the integration of such data for visual, interactive, and immersive displays, but also provides a method for performing risk analysis. Previously "static" VR environments are enhanced with time-evolutionary capabilities. Four candidate algorithms are evaluated for this purpose – deterministic modeling, auto-regressive ...


Congestion Control In Resilient Packet Ring Networks, Alharbi Fahd Dec 2004

Congestion Control In Resilient Packet Ring Networks, Alharbi Fahd

Dissertations

The Resilient Packet Ring (RPR) is a new metro technology; RPR shares SONET's ability in providing fast recovery from link and node failures as well as inherits the cost and simplicity of Ethernet. RPR, like SONET/SDH, is a ring based architecture consisting of two optical rotating rings (uni-directional). In RPR, packets are removed from the ring at the destination so that different segments of the ring can be used at the same time for different flows; as a result, the spatial reuse feature is achieved. Enabling the spatial reuse feature introduces the challenge of guaranteeing fairness among the ...


Development And Application Of Fractionation Procedure For Drinking Water Organic Matters, Yong Pu Dec 2004

Development And Application Of Fractionation Procedure For Drinking Water Organic Matters, Yong Pu

Dissertations

USEPA mandates a control of disinfection by-products (DBPs) in finished drinking water and recommends reduction of natural organic matters (NOM), DBP precursors, to achieve this regulatory goal. Studies relating NOM with DBP include fractionation of water samples, characterization of collected organic fractions, fractions' formation potential tests, and jar or similar tests to remove NOM. This study discussed a current resin fractionation procedure on principle, procedure, and its efficiency when applied to water samples of low NOM (< 5mgIL). The primary objective of this research is to develop a fractionation procedure intended for water of low NOM by carefully applying mass balance concept through each fraction's fractionation and a selection of stable ion exchange resins. A new protocol was presented with triple columns of XAD-8 adsorption resin, one column of AG-MP-50 cationic resin, and another column of WA 10 weak anionic resin in sequence. This protocol was experimented and confirmed for its efficiency (±10% loss of mass) with samples from Canal Road (CR) and Raritan Millstone (RM) surface water treatment plants (WTPs) in central New Jersey. The second objective of this study is to develop a statistical model with a potential of online delineation of organic fractions of NOM. The resulting model based on samples of Passaic Valley Water Commission (PVWC) WTP in northern New Jersey was applied to predict organic fractions of samples from CR and RM plants. Paired T-test (paired t ratio 1.15 < t critical 2.02) indicated a good correlation between the predicted and actual fraction concentration. Finally, samples of Middlesex Water Company (MWC) were fractionated and Trihalomethane formation potential tests (THMFP) on collected fraction showed hydrophilic matters possessed a higher potential to produce TTHM in finished water than hydrophobic matter. Jar tests indicated while coagulation was effective in removing hydrophobic matter, it may not be optimum for removal of hydrophilic matter.

This study developed an accurate fractionation procedure for low NOM waters. It provided a better understanding of organic matter transformation at different treatment stages ...


Bus Arrival Time Prediction Using Stochastic Time Series And Markov Chains, Rajat Rajbhandari Dec 2004

Bus Arrival Time Prediction Using Stochastic Time Series And Markov Chains, Rajat Rajbhandari

Dissertations

Public transit agencies rely on disseminating accurate and reliable information to transit users to achieve higher service quality and attract more users. With the development of new technologies, the concept of providing users with reliable information about bus arrival times at bus stops has become increasingly attractive. Due to the fact that bus operation parameters and variables are highly stochastic, modeling prediction of bus travel and arrival times has become one of the many challenging tasks.

Stochastic time series and delay propagation models to predict bus arrival times using historical information were developed. Markov models were developed to predict propagation ...


A Co-Processor Design To Support Mpi Primitives In Configurable Multiprocessor Designs, Rohan Bafna Dec 2004

A Co-Processor Design To Support Mpi Primitives In Configurable Multiprocessor Designs, Rohan Bafna

Theses

The Message-Passing Interface (MIPI) is a widely used standard for inter-processor communication in parallel computers. This standard is normally implemented in software, thus resulting in large communication latencies. A hardware implementation can reduce communication latencies significantly, thereby increasing the bandwidth. However, this approach cannot be applied in practice to the very large set of functions in MPI.

Reconfigurable computing has reached levels where entire parallel systems can be built inside one or more FPGAs (Field-Programmable Gate Arrays). In this scheme, specialized components must be built for inter-processor communication and the resulting code is difficult to port to other reconfigurable platforms ...


Labview Controlled Study Of The Propagation Properties Of Ultrasound In Synthetic Fog Environment, Aparna Venkataraman Dec 2004

Labview Controlled Study Of The Propagation Properties Of Ultrasound In Synthetic Fog Environment, Aparna Venkataraman

Theses

Diagnostic ultrasound employs pulsed, high frequency sound waves that are reflected back from body tissues and processed by ultrasound receivers to create characteristic images in varied applications such as cardiology, obstetrics and gynecology neurology and urology. Ultrasound intensity is primarily affected by the changes in acoustic impedance of the medium. Literature on ultrasound indicates that the propagation of ultrasound increases gradually as the density increases from air to water. Such studies have been confined to only the three states of matter and have never discussed a fog medium.

The primary objective of this thesis study was to design a system ...


An Autonomous Router-Based Solution To Detect And Defend Low Rate Ddos Attacks, Karunakar Anantharam Dec 2004

An Autonomous Router-Based Solution To Detect And Defend Low Rate Ddos Attacks, Karunakar Anantharam

Theses

Internet security was not a concern when the Internet was invented, but we cannot deny this fact anymore. Since all forms of businesses and communications are aligned to the Internet in one form or the other, the security of these assets (both infrastructure and content) is of prime importance. Some of the well known consequences of an attack include gaining access to a network, intellectual property thefts, and denial of service.

This thesis focuses on countering flood-type attacks that result in denial of service to end users. A new classification of this denial of service attacks, known as the low ...


Study Of Steganalysis Methods, Wen Chen Dec 2004

Study Of Steganalysis Methods, Wen Chen

Theses

Steganography is the art and science of hiding the presence of conmunication by embedding secret message into digital images. The steganographic techniques can be applied in many areas. On one hand, people can benefit from their application. For example, they can be used for copyright protection. On the other hand, these techniques may be used by criminals or terrorists for malicious purposes. For example, terrorists may use the techniques to transmit the secret plan of terror attacks. Law enforcement and security authorities have concerns about such activities. It is necessary to devise the methods to detect steganographic systems. The detection ...


Parameter Based Synthesis Of Sign Language, Amanda Irving Dec 2004

Parameter Based Synthesis Of Sign Language, Amanda Irving

Theses

The primary objective of this project is to demonstrate synthesis of signs in American Sign Language with a finite number of parameters. The parameters in this method include 22 key locations, six location modifiers, six orientation indicators, 46 hand shapes, six predefined movements and seven possible end effectors. These parameters can be used in conjunction with a computer script and they maximize precision and versatility while minimizing development time and resources. The parameters for each sign are stored in an individual text file averaging approximately half a kilobyte.

The success of this project is demonstrated using UGS's Jack Software ...


Obtaining Optimal Data Length For Fmri Images, Vikram M. Natarajan Dec 2004

Obtaining Optimal Data Length For Fmri Images, Vikram M. Natarajan

Theses

Interest in brain hemodynamics has led to a substantial increase in state of the art research within the field of functional Magnetic Resonance Imaging (fMRI). FMRI enables research to be conducted on brain mapping in healthy individuals, as well as in patient populations. The need for accurate functional images is required. The primary objective was the development of a method to determine the optimal number of time points required to obtain reliable activation maps. The second phase involved the development of a program, which enabled the conversion of functional magnetic resonance images to a format that the neurosurgeon's scanner ...