Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

2008

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 4021 - 4050 of 4190

Full-Text Articles in Engineering

Distance Relaying Algorithm For Double-Circuit Transmission Line With Compensation For Reactance Effect Under Standard Availability Of Measurements, Jan Izykowski, Marcin Bozek Jan 2008

Distance Relaying Algorithm For Double-Circuit Transmission Line With Compensation For Reactance Effect Under Standard Availability Of Measurements, Jan Izykowski, Marcin Bozek

Turkish Journal of Electrical Engineering and Computer Sciences

This paper deals with non-pilot distance protection of a double-circuit transmission line. Negative impact of the reactance effect, appearing in measuring a fault loop impedance, on operation of the relay is discussed. An adaptive algorithm allowing one to prevent the relay from mis- or mal-operation caused by the reactance effect is introduced. The algorithm is designed for a standard availability of measurements from one end of the double-circuit line, i.e. when three-phase voltage and current from the faulted line circuit, and additionally zero-sequence current from the healthy line circuit, are provided as the relay input signals. The algorithm is based …

Go to article

Power Distortion Issues In Wind Turbine Power Systems Under Transient States, Tadeusz Lobos, Jacek Rezmer, Tomasz Sikorski, Zbigniew Waclawek Jan 2008

Power Distortion Issues In Wind Turbine Power Systems Under Transient States, Tadeusz Lobos, Jacek Rezmer, Tomasz Sikorski, Zbigniew Waclawek

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper time-frequency methods have been investigated for complex investigations of transient states in wind power plants. Application of parallel processing in time and frequency domain brought new findings in description of wind power plants working under transient conditions. Proposed algorithms represents standard Short-Time Fourier Transform (STFT) as well as alternative methods associated with Cohen's class: Choi-Williams Distribution (CWD) and Zhao-Atlas-Marks Distribution (ZAMD). In order to explore advantages and disadvantages of the method several experiments were performed using model of squirrel-cage induction machine connected directly to the grid. Investigated phenomena concerned power distortion caused by switching-on capacitor banks and …

Go to article

Evolutionary Algorithms For The Unit Commitment Problem, A. Şi̇ma Uyar, Belgi̇n Türkay Jan 2008

Evolutionary Algorithms For The Unit Commitment Problem, A. Şi̇ma Uyar, Belgi̇n Türkay

Turkish Journal of Electrical Engineering and Computer Sciences

This paper compares three evolutionary computation techniques, namely Steady-State Genetic Algorithms, Evolutionary Strategies and Differential Evolution for the Unit Commitment Problem. The comparison is based on a set of experiments conducted on benchmark datasets as well as on real-world data obtained from the Turkish Interconnected Power System. The results of two state-of-the-art evolutionary approaches, namely a Generational Genetic Algorithm and a Memetic Algorithm for the same benchmark datasets are also included in the paper for comparison. The tests show that Differential Evolution is the best performer among all approaches on the test data used in the paper. The performances of …

Go to article

A Unified Methodology Of Maintenance Management For Repairable Systems Based On Optimal Stopping Theory, Hongye Wang Jan 2008

A Unified Methodology Of Maintenance Management For Repairable Systems Based On Optimal Stopping Theory, Hongye Wang

LSU Doctoral Dissertations

This dissertation focuses on the study of maintenance management for repairable systems based on optimal stopping theory. From reliability engineering’s point of view, all systems are subject to deterioration with age and usage. System deterioration can take various forms, including wear, fatigue, fracture, cracking, breaking, corrosion, erosion and instability, any of which may ultimately cause the system to fail to perform its required function. Consequently, controlling system deterioration through maintenance and thus controlling the risk of system failure becomes beneficial or even necessary. Decision makers constantly face two fundamental problems with respect to system maintenance. One is whether or when …

Go to article

Fabrication Of Micro Bumps For Micro Scale Thermal Management, Ajay Ashok Kardak Jan 2008

Fabrication Of Micro Bumps For Micro Scale Thermal Management, Ajay Ashok Kardak

LSU Master's Theses

Cryopreservation is storage of biological systems at ultra low temperatures for a prolonged duration; such that they can be thawed and restored to the same living state. It is important to understand the behavior of cells when they are subjected to subzero temperatures. Research in this area has shown the occurrence of two main biophysical events; cellular dehydration and intracellular ice formation. Current techniques for characterizing the dehydration in cells as part of a tissue are not adequate for studying intracellular ice formation in tissues. An integrated device consisting of an array of thermal sensors (microthermocouples) and actuators (microthermoelectric coolers) …

Go to article

Adsorption And Photochemical Transformation Of Polycyclic Aromatic Hydrocarbons On Atmospheric Water Films, Jing Chen Jan 2008

Adsorption And Photochemical Transformation Of Polycyclic Aromatic Hydrocarbons On Atmospheric Water Films, Jing Chen

LSU Doctoral Dissertations

Atmospheric water films affect the processing of chemicals in the atmosphere and have potential effects on human health and the environment. In this work, adsorption and photochemical transformations of gas-phase PAHs were studied in a flow-tube photo-reactor with a view to understanding the behavior of gas-phase PAHs occurring in thin water films such as those of aerosols and fog. Naphthalene and phenanthrene were chosen as model PAHs for this study. Bulk water-air and air-to-interface partition constants of naphthalene and phenanthrene were estimated from the experiments based on the dependence of the equilibrium uptake on the water film thickness. Theoretical computations …

Go to article

Effect Of Hydrated Lime On The Laboratory Performance Of Superpave Mixtures, Md Sharear Kabir Jan 2008

Effect Of Hydrated Lime On The Laboratory Performance Of Superpave Mixtures, Md Sharear Kabir

LSU Master's Theses

Permanent deformation and moisture damage are the most common distresses found in asphalt pavements today. Extensive experimental studies have revealed that the use of hydrated lime in Hot-Mix Asphalt (HMA) mixtures can reduce permanent deformation, long-term aging, and moisture susceptibility of mixtures. In addition, it increases the stiffness and fatigue resistance of mixtures. The objectives of this study were to evaluate (1) the fundamental engineering properties of HMA mixtures containing hydrated lime compared to conventional mixtures designed to meet the current Louisiana Superpave specifications and (2) the influence of the method of addition of hydrated lime on the mechanical properties …

Go to article

Introducing Hands-On Simulation Activities In Introduction To Engineering & Engineering Technology Class To Keep Students Engaged, Alok Verma Jan 2008

Introducing Hands-On Simulation Activities In Introduction To Engineering & Engineering Technology Class To Keep Students Engaged, Alok Verma

Engineering Technology Faculty Publications

Low enrollment and high attrition rates have often plagued Engineering and Engineering Technology programs. Part of this problem can be attributed to the lack of engaging hands-on activities during the first year of instruction. Most engineering and technology programs require students to take natural science, math and some general education courses during the first two years with minimal technical content. To maintain student's interest in the technical career path, it is important that students establish a link between the theoretical knowledge and its application to solve real life problems early in their learning experience. Simulation based activities have a proven …

Go to article

Analysis Of Resonating Microcantilevers Operating In A Viscous Liquid Environment, Cyril Vančura, Isabelle Dufour, Stephen M. Heinrich, Fabien Josse, Andreas Hierlemann Jan 2008

Analysis Of Resonating Microcantilevers Operating In A Viscous Liquid Environment, Cyril Vančura, Isabelle Dufour, Stephen M. Heinrich, Fabien Josse, Andreas Hierlemann

Civil and Environmental Engineering Faculty Research and Publications

The characteristics of resonant cantilevers in viscous liquids are analyzed. Various rectangular cantilevers geometries are studied in pure water, glycerol and ethanol solutions of different concentrations, and the results are described in terms of the added displaced liquid mass and the liquid damping force for both, the resonance frequency and the quality factor (Q-factor). Experimental results using a set of magnetically actuated resonant cantilevers vibrating in the out-of-plane (“weak-axis bending”) mode are presented and compared to theoretical calculations. The importance of the study is in the use of resonant cantilevers as biochemical sensors in liquid environments.

Go to article

Columbia University/Vireo-Cityu/Irit Trecvid2008 High-Level Feature Extraction And Interactive Video Search, Shih-Fu Chang, Junfeng He, Yu-Gang Jiang, Elie El Khoury, Chong-Wah Ngo, Akira Yanagawa, Eric Zavesky Jan 2008

Columbia University/Vireo-Cityu/Irit Trecvid2008 High-Level Feature Extraction And Interactive Video Search, Shih-Fu Chang, Junfeng He, Yu-Gang Jiang, Elie El Khoury, Chong-Wah Ngo, Akira Yanagawa, Eric Zavesky

Research Collection School Of Computing and Information Systems

In this report, we present overview and comparative analysis of our HLF detection system, which achieves the top performance among all type-A submissions in 2008. We also describe preliminary evaluation of our video search system, CuZero, in the interactive search task.

Go to article

Physical Layer Secrecy Channel Coding, Bandali K. Akkawi Jan 2008

Physical Layer Secrecy Channel Coding, Bandali K. Akkawi

LSU Master's Theses

Wireless communications is expanding and becoming an indispensable part of our daily life. However, due to its channel open nature, it is more vulnerable to attacks, such as eavesdropping and jamming which jeopardize the confidentiality of wireless data, compared to its counter-part, wireline communications. Security in wireless communication is thus a very important factor that should be perfected to accommodate the rapid growth of wireless communication today. Motivated by information theoretic secrecy definitions, we adopt a simple way to define the secrecy of a system by looking at its Bit-Error-Rate (BER) curves, the correlation of error vectors and Log Likelihood …

Go to article

Development Of An Algorithm For Switching Compensator Control Based On The Currents' Physical Components Theory, Samuel Pearce Jan 2008

Development Of An Algorithm For Switching Compensator Control Based On The Currents' Physical Components Theory, Samuel Pearce

LSU Master's Theses

Development of a three-phase switching compensator algorithm, based on the Currents’ Physical Components (CPC) power theory and capable of performing in real time, is the subject of this thesis. The compensator algorithm could be implemented to control a PWM Inverter, which would perform as a shunt switching compensator of harmonic, reactive and unbalanced currents or a customizable combination of the three. The hardware used to demonstrate the ability of the algorithm to perform within the restraints or real time operation is a Motorola DSP56F807 evaluation mode DSP board and a set of voltage and current sensors. The Evaluation Board was …

Go to article

Experimental Investigation Of Unsaturated Soil Stiffness, Ananth Bukkapatnam Tirumala Jan 2008

Experimental Investigation Of Unsaturated Soil Stiffness, Ananth Bukkapatnam Tirumala

LSU Master's Theses

Soil stiffness is a strain dependent non-linear parameter. Stiffness is the measure of soil deformation under a particular working load. It can used for predicting ground deformation in engineering earthworks such as highway embankments and foundations. Non-linear analyses for ground behavior have been widely used for developing models to predict the small –strain characteristics of the soil (Atkinson, 2000). This thesis provides a new insight into the behavior of soil stiffness. We used the wave propagation technique to determine the stiffness and term it as the small strain shear modulus (Gmax) of the soil. The objective of the thesis was …

Go to article

Internal Cooling In Ribbed Rectangular (Ar=4:1) Passages At High Rotation Numbers And Improvement In Finning Strategies, Fuguo Zhou Jan 2008

Internal Cooling In Ribbed Rectangular (Ar=4:1) Passages At High Rotation Numbers And Improvement In Finning Strategies, Fuguo Zhou

LSU Doctoral Dissertations

Experimental studies have been performed on two-pass rectangular internal coolant channels with aspect ratio AR 4:1 with high rotation numbers. Three passages are investigated: smooth, 90 deg ribbed and 45 deg ribbed. A maximum Reynolds number of 150,000 and a maximum rotation number of 0.6 are achieved in the study. These maximum parameter values are considerably higher than those previously reported for the 4:1 AR geometry, and provide data for parameter ranges that may be representative of certain modern turbine blades. Heat transfer behaviors with rotation in the three passages are presented. Rotation effects, density effects and buoyancy effects are …

Go to article

Elasto-Plastic And Damage Modeling Of Reinforced Concrete, Ziad N. Taqieddin Jan 2008

Elasto-Plastic And Damage Modeling Of Reinforced Concrete, Ziad N. Taqieddin

LSU Doctoral Dissertations

Modeling the mechanical behavior of Reinforced Concrete (RC) is still one of the most difficult challenges in the field of structural engineering. The Nonlinear Finite Element Analysis (NFEA) and modeling of the behavior of RC members are the primary goals of this study. The macroscopic components of RC, Concrete material and reinforcing steel, are represented herein by separate material models. These material models are combined together using a model that describes the global effect of interaction between reinforcing steel and concrete in order to simulate the behavior of the composite RC material. A thermodynamically consistent constitutive model for concrete that …

Go to article

Moderately-Rapid Assessment Of Alkaline Desiccation Environmental Systems, David Alan Bates Jan 2008

Moderately-Rapid Assessment Of Alkaline Desiccation Environmental Systems, David Alan Bates

LSU Doctoral Dissertations

A moderately-rapid assessment tool was developed to analyze the waterless desiccation compost toilet investigated in a rural Mexican setting. Over 100 social factors were identified along with the applicable technical factors that influenced the low acceptability of the toilets. A 4-point rating scale was developed to increase the ability and speed of analyzing both the social and technical data. The treatment process was an alkaline-desiccation process with mean pH values of 8.2 ± sd 1.1 and water content of 18.3% ± sd 9.9, which resulted in mean fecal coliform values of 15.0 MPN/g ± sd 31.8, drastically lower than the …

Go to article

Nonlocal Gradient-Dependent Modeling Of Plasticity With Anisotropic Hardening, Gerald Pekmezi Jan 2008

Nonlocal Gradient-Dependent Modeling Of Plasticity With Anisotropic Hardening, Gerald Pekmezi

LSU Master's Theses

This work is concerned with the formulation of the thermodynamics of nonlocal plasticity using the gradient theory. The formulation is based on the nonlocality energy residual introduced by Eringen and Edelen (1972). Gradients are introduced for those variables associated with isotropic and kinematic hardening. The formulation applies to small strain gradient plasticity and makes use of the evanescent memory model for kinematic hardening. This is accomplished using the kinematic flux evolution as developed by Zbib and Aifantis (1987). Therefore, the present theory is a four nonlocal parameter-based theory that accounts for the influence of large variations in the plastic strain, …

Go to article

Voltage Dip Mitigation For Motor Starters Using An Adaptive High Speed Relay Protection On The High Voltage Transmission System, Cesar Alberto Rincon Jan 2008

Voltage Dip Mitigation For Motor Starters Using An Adaptive High Speed Relay Protection On The High Voltage Transmission System, Cesar Alberto Rincon

LSU Master's Theses

Currently, the aging state of the protection systems for industrial facilities is calling for a system-wide review of the equipment and the protection schemes used in all these places, calling for a new approach in the design and implementation of these systems. Some of these facilities house critical processes that can be seriously affected by a misoperation of equipment or a disturbance in the system, aspects ranging from safety of plant workers to millions of dollars in loss of production. In this thesis different contingency situations were explored for problems in the utility transmission system that could affect large industrial …

Go to article

Photocatalytic Oxidation Of Ethanol Using Macroporous Titania, Gibert Merle Magpantay Jan 2008

Photocatalytic Oxidation Of Ethanol Using Macroporous Titania, Gibert Merle Magpantay

LSU Master's Theses

Photocatalytic oxidation (PCO) using TiO2 is a potential means of remediating poor indoor air quality that is attributed to low levels of volatile organic compounds (VOC). In this work, ethanol is chosen as a simple compound representative of VOC’s. The aim of this research is to establish a baseline for the photocatalytic activity of TiO2 in ethanol PCO as well as the photonic efficiency of the photoreactor. The PCO conversion could then be enhanced by using photocatalyst having a macroporous structure. A flat plate photoreactor, UV light delivery and a flow system was designed in this work to accomplish ethanol …

Go to article

Application Of The Hyman Model To Evaluate The Water And Salt Budgets In Three Mangrove Sites Along Shark River, Everglades, Cheng-Feng Tsai Jan 2008

Application Of The Hyman Model To Evaluate The Water And Salt Budgets In Three Mangrove Sites Along Shark River, Everglades, Cheng-Feng Tsai

LSU Master's Theses

Mangrove trees play an important role in the maintenance and sustainability of coastal wetlands due to their ability to adapt and survive in a wide range of saline and tidal conditions. Hydrologic processes (e.g., inundation frequency) and salinity are important regulators controlling the growth and productivity of mangrove forests. To quantify how changes in landscape-level hydrology will influence these regulators in mangrove forests, the hydrology model (HYMAN) was applied to three sites with distinct tidal forcings along the Shark River estuary in the Everglades National Park. HYMAN model uses mass balance equation to determine daily water and salt budgets as …

Go to article

Mercury Transport Through A Capped Sediment, Jianrong Liu Jan 2008

Mercury Transport Through A Capped Sediment, Jianrong Liu

LSU Doctoral Dissertations

Laboratory simulation cells were employed to evaluate the effectiveness of a sand cap for containing highly mercury-contaminated lake sediments and the resultant impacts on the mercury fate beneath the cap. Sand cap can delay and reduce the migration of mercury into the overlying water; however, due to the small partition coefficient of mercury between sand and water, a capping material with higher partition coefficient is better for the long-term containment of mercury. In the following study, efforts were made to identify and investigate an active capping material which works effectively at containing and inhibiting the methylation of mercury. Based on …

Go to article

Degradation And Water Quality Dynamics Of Sugarcane Residue In South Louisiana, Jose Roberto Deras Jan 2008

Degradation And Water Quality Dynamics Of Sugarcane Residue In South Louisiana, Jose Roberto Deras

LSU Doctoral Dissertations

PURPOSE: This research was conducted to assess methods to manage the residue blanket to avoid open field burning in sugarcane. Experiments were conducted in the state of Louisiana to evaluate methods to asses and potentially reduce water quality issues. METHODS: Concentrations and frequencies of biological compost tea were sprayed on sugarcane combine-harvester residue blanket to increase degradation rate and reduce potential for runoff water to transport nutrients and sediments that may impair water bodies, while sustaining suitable sugarcane yield. Carbon dioxide evolution rate (mg CO2-C) and CO2 fluxes were measured in laboratory and in open field conditions; as an index …

Go to article

Magnetic Field Effects On Diffusion Flames, Diego F. Gonzalez Jan 2008

Magnetic Field Effects On Diffusion Flames, Diego F. Gonzalez

LSU Master's Theses

Magnetic field effects in combustion is an area of study that has previously been overlooked. The influence of magnetic fields on flames has only recently been explored and is of interest both from a scientific and a practical standpoint. This study provides theoretical, numerical and experimental evidence that combustion can be affected with the use of suitable magnetic fields. This thesis focuses on four different types of magnetic field: homogeneous, gradient, oscillating and pre-combustion. For the homogeneous field case, the Gibbs Free Energy method was used to determine the mole fraction of product species. It was found that homogeneous fields …

Go to article

Lattice Boltzmann Modeling For Mass Transport Equations In Porous Media, Borja Servan Camas Jan 2008

Lattice Boltzmann Modeling For Mass Transport Equations In Porous Media, Borja Servan Camas

LSU Doctoral Dissertations

The aim of this dissertation is to extend the lattice Boltzmann method (LBM) to cope with parameter heterogeneity and anisotropy in mass transport equations in porous media, as well as investigating the stability and accuracy. Although the LBM is a well known and effective numerical method to solve fluid flows, LBM has not been extensively applied to mass transport equations in porous medium flow yet, and only a few works can be found on improving LBM to cope with mass transport equations other than the diffusion and advection-diffusion equations. One of the reasons why LBM has not been extensively used …

Go to article

My Collaboration With Raj Mittra: Contributions To The Theory Of Perfectly Matched Layers, Mustafa Kuzuoğlu Jan 2008

My Collaboration With Raj Mittra: Contributions To The Theory Of Perfectly Matched Layers, Mustafa Kuzuoğlu

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.

Go to article

From Engineering Electromagnetics To Electromagnetic Engineering: Using Computational Electromagnetics For Synthesis Problems, Anton G. Tijhuis, Martijn C. Van Beurden, Bastiaan P. De Hon, Hubregt J. Visser Jan 2008

From Engineering Electromagnetics To Electromagnetic Engineering: Using Computational Electromagnetics For Synthesis Problems, Anton G. Tijhuis, Martijn C. Van Beurden, Bastiaan P. De Hon, Hubregt J. Visser

Turkish Journal of Electrical Engineering and Computer Sciences

In this paper, a two-stage approach is proposed for using computational electromagnetics in antenna engineering. First, stochastic optimization techniques are used in combination with approximate models. Second, line-search techniques are combined with full-wave modeling. For the first stage, we show an illustrative example. The second stage is considered in detail; both the acceleration of the underlying field computations and the implementation of the optimization are discussed.

Go to article

A Summary Of Recent Developments On Metamaterial-Based And Metamaterial-Inspired Efficient Electrically Small Antennas, Aycan Erentok, Richard W. Ziolkowski Jan 2008

A Summary Of Recent Developments On Metamaterial-Based And Metamaterial-Inspired Efficient Electrically Small Antennas, Aycan Erentok, Richard W. Ziolkowski

Turkish Journal of Electrical Engineering and Computer Sciences

This paper summarizes our recent research efforts to realize efficient electrically small antenna (EESA) systems based on ideal analytical and numerical metamaterial-based antenna systems, and physically realized metamaterial-inspired antenna designs. Our theoretical and numerical studies of the radiation and resonance behaviors of the proposed metamaterial-based EESA systems, as well as our efforts to conceptualize structures which might be used to build them, have led to the discovery of several realizable metamaterial-inspired EESA systems. The measurement results confirm the numerical performance predictions.

Go to article

Dual-Band Split-Ring Antenna Design For Wlan Applications, S. Cumhur Başaran, Yunus E. Erdemli̇ Jan 2008

Dual-Band Split-Ring Antenna Design For Wlan Applications, S. Cumhur Başaran, Yunus E. Erdemli̇

Turkish Journal of Electrical Engineering and Computer Sciences

A dual-band microstrip antenna based on split-ring elements is introduced for WLAN (2.4/5.2 GHz) applications. The proposed split-ring antenna (SRA) has a compact novel design which provides about 2% impedance-bandwidth without a need for additional matching network. Analysis and design of the proposed microstrip antenna is carried out by means of full-wave simulators based on the finite-element method.

Go to article

Determinants Of Financial Health Of Us General Aviation Airports, Vitaly S. Guzhva, Massoud Bazargan, David A. Byers Jan 2008

Determinants Of Financial Health Of Us General Aviation Airports, Vitaly S. Guzhva, Massoud Bazargan, David A. Byers

Management, Marketing and Operations - Daytona Beach

This survey-based study investigates the current financial environment of US general aviation airports. Due to a dearth of data and research on the financial performance of general aviation airports, the paper provides vital information regarding the critical needs and major revenue sources of such airports.The findings suggest that general aviation airports can be self-sustaining regardless of their location, runway length and other airport-specific characteristics.The attitudes of the airport manager towards the importance of financial self-sustainability, positive relationships with local communities, and utilisation of non-traditional and non-aviation revenue sources are found to be critical for the financial health of general aviation …

Go to article

The Use Of Modeling Tools In The Analysis Of Functional Requirements, Gopi Kamadia Jan 2008

The Use Of Modeling Tools In The Analysis Of Functional Requirements, Gopi Kamadia

All ETDs from UAB

The thesis offers an Object-Oriented analysis methodology to investigate the functional requirements of software systems with modeling technologies, such as Unified Modeling Language (UML) and Systems Modeling Language (SysML). The main focus of the analysis is to discover objects and describe them in the problem domain. The thesis also proposes a validation process for the requirements stage of the development life cycle with an Acclaro Design For Six Sigma (DFSS) approach. A software development experiment is carried out with a case study of a threedimensional graphics game. The game is first implemented without following any sound analysis process and then …

Go to article

First Prev Next Last