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2007

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Articles 3211 - 3240 of 3831

Full-Text Articles in Engineering

The Shape Of Pulverized Bituminous Vitrinite Coal Particles, Jonathan P. Mathews, Patrick G. Hatcher, Alan W. Scaroni Jan 2007

The Shape Of Pulverized Bituminous Vitrinite Coal Particles, Jonathan P. Mathews, Patrick G. Hatcher, Alan W. Scaroni

Chemistry & Biochemistry Faculty Publications

The shape of pulverized bituminous coal particles (vitrinites) was determined by optical and laser light scattering. Vitrain samples were collected from obvious tree remains located in the ceilings of two Appalachian coal mines. Wet sieving produced narrow size cuts. The particles were determined to be oblong or blocky in shape, with average length-to-width ratio of 1.7 and sphericity of 0.78. They were analogous in shape to a square ended, rectangular "house brick". The two bituminous coals and different size cuts of each coal had essentially the same shape parameters. Characteristic heating times and terminal velocities were higher by 22 and …

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Channel Modeling And Resource Allocation In Ofdm Systems, Xiang Gao Jan 2007

Channel Modeling And Resource Allocation In Ofdm Systems, Xiang Gao

LSU Doctoral Dissertations

The increasing demand for high data rate in wireless communication systems gives rise to broadband communication systems. The radio channel is plagued by multipath propagation, which causes frequency-selective fading in broadband signals. Orthogonal Frequency-Division Multiplexing (OFDM) is a modulation scheme specifically designed to facilitate high-speed data transmission over frequency-selective fading channels. The problem of channel modeling in the frequency domain is first investigated for the wideband and ultra wideband wireless channels. The channel is converted into an equivalent discrete channel by uniformly sampling the continuous channel frequency response (CFR), which results in a discrete CFR. A necessary and sufficient condition …

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Electrodeposition Of Multilayered Nanostructures For Giant Magnetoresistance And Thermoelectric Applications, Despina Davis Jan 2007

Electrodeposition Of Multilayered Nanostructures For Giant Magnetoresistance And Thermoelectric Applications, Despina Davis

LSU Doctoral Dissertations

The electrodeposition of novel materials such as multilayer nanotubes for giant magneto resistance (GMR) applications and bismuth telluride nanotubes for thermoelectric applications are presented in this dissertation. The motivation for the multilayer electrodeposition is the investigation of giant magnetoresistance (GMR), a change in the material resistance in an applied magnetic field as a consequence of antiferromagnetic coupling. The nanowire high aspect ratio geometry allows the measurement of GMR with the current applied perpendicular to the plane (CPP) of the multilayers, which has been theoretically identified as being larger than the GMR in the (CIP) configuration (current in plane of multilayers). …

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Engineering A Photo-Control Mechanism For Rna Interference, Richard Andrew Blidner Jan 2007

Engineering A Photo-Control Mechanism For Rna Interference, Richard Andrew Blidner

LSU Doctoral Dissertations

RNA interference (RNAi) is a phenomenon in which RNA molecules elicit potent and sequence-specific post-transcriptional gene silencing. Nucleic acid chemical modifications have been incorporated to improve their pharmacological properties. Despite numerous developments in chemical modifications for increased stability, safety, and efficiency of these therapeutic agents, they still face challenges of spatial and temporal targeting. One potential targeting strategy uses photocaging techniques, which involves the covalent attachment of photolabile compounds to the effector NA species that blocks bioactivity until exposed to near UV-light. This work demonstrates that fully-2’-fluorinated nucleic acids (FNAs) can elicit RNAi and that these effectors are resistant to …

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Computer Model Of Hybrid Compensator Of Fast Varying Loads, Veronica Bohorquez Jan 2007

Computer Model Of Hybrid Compensator Of Fast Varying Loads, Veronica Bohorquez

LSU Doctoral Dissertations

A computer model of the hybrid compensator of fast varying loads was developed in this dissertation. The computer model was implemented in MFC Visual C++ compiler version 6.0. The classification of fast varying loads and effects of their operation in distribution systems were described in this dissertation. The power properties of fast varying loads were expressed in terms of the Currents' Physical Components Theory. Therefore, the Currents' Physical Components Theory was applied to systems with non-periodic voltages and currents. The supply current of the fast varying loads was decomposed into the useful and the useless components using an algorithm based …

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Effects Of Capping On Biodegradation Of Organic Contaminants In Sediments, Eun Ju Lee Jan 2007

Effects Of Capping On Biodegradation Of Organic Contaminants In Sediments, Eun Ju Lee

LSU Doctoral Dissertations

Sediment capping remains an effective remediation technique for contaminated sediments due to its capability to contain contaminants and provide a sound habitat for indigenous biota. This research investigated the effect of capping on biodegradation of organic contaminants in Anacostia River sediments using both experimental and modeling techniques. 14C–Phenanthrene mineralization was monitored under various redox conditions in Anacostia River sediments. Mineralization of 14C–phenanthrene was strongly linked to sulfate reduction, which was the more energetic process than any other anaerobic condition in Anacostia sediments. Sulfate is a more promising terminal electron acceptor for intrinsic degradation in Anacostia River and other PAH contaminated …

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Turbulence Modeling For Film Cooling Flows, Asif Hoda Jan 2007

Turbulence Modeling For Film Cooling Flows, Asif Hoda

LSU Doctoral Dissertations

An improved two equation turbulence model has been developed in this dissertation to better predict the complex film cooling flow field that is formed from the interaction of a coolant jet and a crossflow over a modeled turbine blade surface. Film cooling of turbine blades is commonly employed to effectively protect turbine blades from thermal failure and thereby to allow higher inlet temperatures in order to increase the efficiency of gas turbine engines. Film cooling involves the injection of rows of coolant jets from slots on the surface of a turbine blade which is then bent over by the crossflow …

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Electrodeposition Of Rare Earth-Transition Metal Alloy Thin Films And Nanostructures, Rohit Mishra Jan 2007

Electrodeposition Of Rare Earth-Transition Metal Alloy Thin Films And Nanostructures, Rohit Mishra

LSU Doctoral Dissertations

Rare earth-transition metal alloys are of interest in MEMS and magnetic storage industries because of their unique magnetic properties. However, the applications of these alloys have been limited to bulk and thin film architectures because of the limitations of the contemporary vapor deposition technique to fabricate high aspect ratio nanostructures. The objective of this study is to develop an electrochemical process to deposit rare earth-transition metal alloys thus making it possible to deposit high aspect ratio nanostructures such as nanowires and nanotubes, which helps to tune their properties for specific applications. Electrodeposition of rare earth-transition metal alloys was achieved from …

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Particle And Dredge-Scale Kinetic Studies Of Hydrophobic Organic Chemical Desorption From Sediment, Justin Edward Birdwell Jan 2007

Particle And Dredge-Scale Kinetic Studies Of Hydrophobic Organic Chemical Desorption From Sediment, Justin Edward Birdwell

LSU Doctoral Dissertations

The discharge of hydrophobic organic chemicals (HOCs) and other hazardous substances from anthropogenic sources to surface waters and the atmosphere has led to the widespread contamination of bottom sediments throughout the world. HOCs collect in sediments due to their affinity for organic matter and other sorbents present on and within their solid matrices. There is interest in the movement of HOCs from historically contaminated, resuspended sediments to surface waters due to the connection between chemical desorption and bioavailability. Quantitatively accurate predictions of contaminant concentrations in environmental media are needed for reliable risk assessment and to develop strategies for protection of …

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Characterization Of Advanced Composites- A Nondestructive Approach, Phani Surya Kiran Mylavarapu Jan 2007

Characterization Of Advanced Composites- A Nondestructive Approach, Phani Surya Kiran Mylavarapu

LSU Doctoral Dissertations

Adhesively bonded sandwich structures comprising of particulate composites as core and graphite epoxy skins as stiffeners are widely used for various applications in the marine and aerospace industry. The core material and the stiffener are held together by an adhesive bond. Particulate composites are made from a mixture of a polymer resin and hollow or solid particles. Hollow particulate composites are known as syntactic foams. Particulate composites possess attractive mechanical and physical properties such as high compressive strength etc, making them attractive materials for use in structural applications. Characterization of the adhesive bondline and core material in sandwich structures is …

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Wetting Kinetics Of A Thin Film Evaporating In Air, S. Saritha, Partho Neogi Jan 2007

Wetting Kinetics Of A Thin Film Evaporating In Air, S. Saritha, Partho Neogi

Chemical and Biochemical Engineering Faculty Research & Creative Works

The conservation equation and the equations of motion are solved for a case where a thin liquid film moves out of a slot onto a horizontal surface. The liquid is allowed to evaporate into air. The evaporation process is taken to be isothermal. Lubrication theory approximation is used where only the tangential velocity and its dependence only in the normal direction are considered. The dynamics of thin films includes the use of disjoining pressure for a pure liquid and where there is a dissolved polymer. The results show that evaporation is quicker than film thinning such that a spreading regime …

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Training For Adjunct Faculty, Ronald Welch, Allen Estes, Carol Considine Jan 2007

Training For Adjunct Faculty, Ronald Welch, Allen Estes, Carol Considine

Engineering Technology Faculty Publications

Professor, teacher, instructor, faculty member –all are cherished and incredibly important titles at any university. At the same time, every full-time faculty member knows that it took time to become a good teacher and that training and mentoring shortens the required train-up period. Members of the Civil Engineering Department Heads Council Executive Committee (DHCEC) have indicated that the American Society of Civil Engineers (ASCE) ExCEEd Teaching Workshop is a must have tool for developing new faculty. So why do we thrust a syllabus into the hands of adjunct faculty and wish them well – while it appears that some type …

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Bioelectric Effects Of Intense Nanosecond Pulses, Karl H. Schoenbach, Barbara Y. Hargrave, Ravindra P. Joshi, Juergen F. Kolb, Richard Nuccitelli, Christopher J. Osgood, Andrei G. Pakhomov, Michael W. Stacey, James R. Swanson, Jody A. White, Shu Xiao, Jue Zhang, Stephen J. Beebe, Peter F. Blackmore, E. Stephen Buescher Jan 2007

Bioelectric Effects Of Intense Nanosecond Pulses, Karl H. Schoenbach, Barbara Y. Hargrave, Ravindra P. Joshi, Juergen F. Kolb, Richard Nuccitelli, Christopher J. Osgood, Andrei G. Pakhomov, Michael W. Stacey, James R. Swanson, Jody A. White, Shu Xiao, Jue Zhang, Stephen J. Beebe, Peter F. Blackmore, E. Stephen Buescher

Bioelectrics Publications

Electrical models for biological cells predict that reducing the duration of applied electrical pulses to values below the charging time of the outer cell membrane (which is on the order of 100 ns for mammalian cells) causes a strong increase in the probability of electric field interactions with intracellular structures due to displacement currents. For electric field amplitudes exceeding MV/m, such pulses are also expected to allow access to the cell interior through conduction currents flowing through the permeabilized plasma membrane. In both cases, limiting the duration of the electrical pulses to nanoseconds ensures only nonthermal interactions of the electric …

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Anchoring Energy And Pretilt Angle Effects On Liquid Crystal Response Time, Xiangyi Nie Jan 2007

Anchoring Energy And Pretilt Angle Effects On Liquid Crystal Response Time, Xiangyi Nie

Electronic Theses and Dissertations

This dissertation covers some important topics on the liquid crystal-substrate surface effects, including theoretical derivations and confirming experimental results. The research work is expected to make important impacts on liquid crystal device designs and to open new doors for further research along these topics. In this dissertation, a novel high-electric-field technique is developed to characterize the anchoring energy of vertically-aligned liquid crystal cells. Both theoretical analyses and confirming experimental results are presented. Vertically-aligned liquid crystal cells with buffed polyimide alignment layers are used to validate the measurement techniques. Based on the voltage-dependent transmittance of the liquid crystal cells, a linear …

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A Study Of Equatorial Ionopsheric Variability Using Signal Processing Techniques, Xiaoni Wang Jan 2007

A Study Of Equatorial Ionopsheric Variability Using Signal Processing Techniques, Xiaoni Wang

Electronic Theses and Dissertations

The dependence of equatorial ionosphere on solar irradiances and geomagnetic activity are studied in this dissertation using signal processing techniques. The statistical time series, digital signal processing and wavelet methods are applied to study the ionospheric variations. The ionospheric data used are the Total Electron Content (TEC) and the critical frequency of the F2 layer (foF2). Solar irradiance data are from recent satellites, the Student Nitric Oxide Explorer (SNOE) satellite and the Thermosphere Ionosphere Mesosphere Energetics Dynamics (TIMED) satellite. The Disturbance Storm-Time (Dst) index is used as a proxy of geomagnetic activity in the equatorial region. The results are summarized …

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Critical Route Network For Earthquake Response And Dynamic Route Analysis, Srinivas Peeta, Georgios Kalafatas Jan 2007

Critical Route Network For Earthquake Response And Dynamic Route Analysis, Srinivas Peeta, Georgios Kalafatas

JTRP Technical Reports

Earthquakes can significantly disrupt societal functioning, cause ecological damage, and lead to loss of human lives and property, warranting a coordinated and efficient response to mitigate their negative impacts. Preparedness against earthquakes entails a pre-disaster planning aspect and a post disaster operational aspect. In the JTRP study “Emergency Earthquake Routes for the State of Indiana; Part I: Criteria for Selection of Primary Routes: Transportation Aspects”, a multicommodity maximal covering network design formulation based optimization methodology was proposed to identify a critical routes sub-network for the Indiana component of the Wabash Valley Seismic Zone in the INDOT Vincennes District. Addressed from …

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Factors In Debris Accumulation At Bridge Piers, Dennis A. Lyn, Thomas J. Cooper, Charles Anthony Condon, Lu Gan Jan 2007

Factors In Debris Accumulation At Bridge Piers, Dennis A. Lyn, Thomas J. Cooper, Charles Anthony Condon, Lu Gan

JTRP Technical Reports

Debris accumulation at bridge piers has been a significant problem at a number of bridge sites in Indiana, increasing risks of upstream flooding, scour, and stream instability. The current study aimed at identifying factors contributing to debris accumulation in order to formulate guidelines for the design of new bridges that would minimize their occurrence or impact. Three related approaches were taken: i) a systematic study of the available underwater bridge inspections reports, ii) a program of periodic visits and visual examination of bridge sites that were thought to be prone to debris accumulation, and iii) continued video monitoring of three …

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Investigating Text Message Classification Using Case-Based Reasoning, Matt Healy Jan 2007

Investigating Text Message Classification Using Case-Based Reasoning, Matt Healy

Masters

Text classification is the categorization of text into a predefined set of categories. Text classification is becoming increasingly important given the large volume of text stored electronically e.g. email, digital libraries and the World Wide Web (WWW). These documents represent a massive amount of information that can be accessed easily. To gain benefit from using this information requires organisation. One way of organising it automatically is to use text classification. A number of well known machine learning techniques have been used in text classification including Naïve Bayes, Support Vector Machines and Decision Trees, and the less commonly used are k-Nearest …

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Transfer Function Modelling: A Student-Centred Learning Approach, Aidan O'Dwyer Jan 2007

Transfer Function Modelling: A Student-Centred Learning Approach, Aidan O'Dwyer

Conference papers

Traditionally, the modelling of real systems in engineering, using transfer functions, has been done in a mathematically intense manner. However, non-traditional learners such as mature students, part-time students and students without a conventional second-level educational background may not have strong mathematical foundations; in addition, all students increasingly expect technical work which is practical and which motivates independent learning. This paper reports on, reflects on and evaluates an innovative experiment developed by the author to estimate a transfer function model of a person’s eye-brain-hand motor response. In the experiment, carried out using a PC with data acquisition capability, the person is …

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Experiences With Virtual Learning Environments In Control Engineering Education, Aidan O'Dwyer Jan 2007

Experiences With Virtual Learning Environments In Control Engineering Education, Aidan O'Dwyer

Conference papers

The twin pressures of the need for students to learn a wider variety of concepts, ideally in a self-learning mode, and the reduction in class contact time has led to the use of increased levels of information technology in control engineering education. This paper reports on, reflects on, and evaluates the author’s use of virtual laboratories (computer based laboratories available on the internet) in control engineering modules at DIT Kevin St. The use of the virtual laboratories helps in the ongoing evolution of the teaching approach from a traditional didactic lecture and laboratory course to a more learner-centred approach. The …

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Stability Analysis And Control Synthesis Of Affine Fuzzy Systems, Ruiyao Gao, Aidan O'Dwyer Jan 2007

Stability Analysis And Control Synthesis Of Affine Fuzzy Systems, Ruiyao Gao, Aidan O'Dwyer

Conference papers

This paper presents an approach to stability analysis and control synthesis of affine fuzzy systems. The analysis is based on quadratic Lyapunov functions. The approach considers the nonlinear offset terms in affine fuzzy systems as non-vanishing perturbations added to the corresponding nominal linear blending systems. The affine fuzzy system is bounded by an ultimate limit if the corresponding linear blending system is exponentially stable. A state feedback controller with an extra term is designed with guaranteed global stability. The ultimate bounds are determined for both the open loop system and the compensated system.

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Identification Of A Time-Delayed Process Model Using An Overparameterisation Method, John Roe, Ruiyao Gao, Aidan O'Dwyer Jan 2007

Identification Of A Time-Delayed Process Model Using An Overparameterisation Method, John Roe, Ruiyao Gao, Aidan O'Dwyer

Conference papers

An extensive literature exists on the estimation of the model parameters of time-delayed processes. This paper briefly reviews the main overparameterisation methods for the Single-Input, Single Output (SISO) and Multi-Input, Multi-Output (MIMO) model parameter (and time delay) estimation problem. Subsequently, two algorithms, and their modifications, are discussed, and their performances are assessed in simulation. Results indicate that both the algorithms can suitably identify the model parameters, including the time delay. The third author has taught the method successfully to students taking advanced level control courses at DIT for a number of years; these experiences will be briefly reported. The paper …

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Some Aspects Of Process Control In Semiconductor Manufacturing, Keelin Relihan, Shane Geraghty, Aidan O'Dwyer Jan 2007

Some Aspects Of Process Control In Semiconductor Manufacturing, Keelin Relihan, Shane Geraghty, Aidan O'Dwyer

Conference papers

This paper outlines some aspects of process control in semiconductor manufacturing. Starting with an outline of the semiconductor manufacturing process, the contribution will discuss temperature control of the chemical vapour deposition stage and the control of the wafer etching process, based on the industrial experience of the first two authors. Subsequently, the authors draw the attention of the semiconductor manufacturing community to the potential of properly tuned PID controllers for the achievement of simple and high performance control solutions.

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Experiences Of Assessment Using Multiple Choice Questions On A First Year Engineering Module In Electrical Engineering, Aidan O'Dwyer Jan 2007

Experiences Of Assessment Using Multiple Choice Questions On A First Year Engineering Module In Electrical Engineering, Aidan O'Dwyer

Conference papers

This contribution will report on, and evaluate, the use of multiple-choice questions, in both continuous assessment and terminal examination modes, on a first year module in electrical engineering at Dublin Institute of Technology. The author’s experiences are that multiple-choice questions tend to be student friendly (e.g. given a choice in a terminal examination, students will opt to attempt the questions with multiple choice parts). The author has used the assessment method over three academic years, and some assessment data is reported and analysed in the contribution. The pedagogical approach is explicitly pragmatic.

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Biotechnology, Life Sciences And Control Engineering:Some Synthesis Issues, Aidan O'Dwyer Jan 2007

Biotechnology, Life Sciences And Control Engineering:Some Synthesis Issues, Aidan O'Dwyer

Conference papers

The synthesis of biotechnology, life sciences and control engineering is receiving increasing interest. The purpose of this contribution (and the associated poster) is to raise awareness of some of this synthesis work.

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Hazardous Emissions Monitoring And Control, Aidan O'Dwyer, Jesus Cabello Jan 2007

Hazardous Emissions Monitoring And Control, Aidan O'Dwyer, Jesus Cabello

Conference papers

There is an increasing awareness in society of the need to protect our fragile environment. Meeting environmental requirements is recognised as one of the six 21st century business drivers for automatic control. Chemical companies, for example, use automatic control to minimise waste production because of increasing prohibitions against discharge and/or disposal of toxic substances. New plants are moving towards a “zero-discharge” concept [1]. In a recent report [2], greater emphasis on automatic control is suggested as a technological response of both the speciality chemicals and pharmaceutical sub-sectors to key business drivers up to 2015. This contribution reports on recent developments …

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Sensors For The Detection Of Hazardous Emissions, Aidan O'Dwyer Jan 2007

Sensors For The Detection Of Hazardous Emissions, Aidan O'Dwyer

Conference papers

This contribution will detail recent developments in sensor technology for the detection of hazardous emissions. The accurate measurement of such emissions is necessary if they are to be controlled to the appropriate regulations.

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Design Of Compact Multi-Band Ebg Structures, Xiulong Bao, Max Ammann Jan 2007

Design Of Compact Multi-Band Ebg Structures, Xiulong Bao, Max Ammann

Conference papers

Several novel compact multiple-band high-impedance surface EBG structures are presented. By utilizing four S-shape corrugated arms or spiral arms connected to the edge of a small square patch to increase the inductance, the resonant frequency of the EBG structure can be significantly reduced. In order to broaden the width of the stopband and adjust the ratio of the centre frequencies for multi-band EBG a log periodic distance between the S-shape strips is implemented. The effects of the parameters of the EBG structure on the width of stopbands are discussed in detail. The results show that the proposed novel EBG structure …

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Miniaturized Annular Ring Loaded Patch Antennas, Max Ammann, Xiulong Bao Jan 2007

Miniaturized Annular Ring Loaded Patch Antennas, Max Ammann, Xiulong Bao

Conference papers

The proliferation of wireless communication systems has promoted the development of miniaturized antenna designs. Annular ring patch antennas are reported to reduce antenna size. In this paper, several novel compact probe-fed annular-ring microstrip patch antennas are presented. In order to reduce the antenna size and provide a suitable input impedance match, two techniques are employed; the insertion of strips into the annular ring and placing a cross-slot into the ground plane. The proposed annular-ring patch antennas with a cross-slotted ground plane yield a much smaller size for a given frequency and are easily matched to 50 Ohms. These novel patch …

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Low-Profile Rolled Planar Antenna With Wide Bandwidth, Giuseppe Ruvio, Max Ammann Jan 2007

Low-Profile Rolled Planar Antenna With Wide Bandwidth, Giuseppe Ruvio, Max Ammann

Conference papers

A novel size-reduction technique for a planar monopole type antenna is presented. By rolling the planar element of this antenna, a low-profile radiator with broad impedance bandwidth is obtained without excessively perturbing its radiation properties. The proposed antenna is capable of covering frequencies in the range 3.1 GHz to 15 GHz. The antenna yields a high gain with high radiation efficiency across the full bandwidth. Radiation patterns show good omnidirectional features, so it is a remarkable candidate for in-door or vehicular applications where large frequency range is required

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