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2005

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Articles 691 - 720 of 3074

Full-Text Articles in Engineering

An Approximate Solution To Buckling Of Plates By The Galerkin Method, Yattender Rishi Dubey Aug 2005

An Approximate Solution To Buckling Of Plates By The Galerkin Method, Yattender Rishi Dubey

Mechanical and Aerospace Engineering Theses - Archive

This thesis presents a semi-analytical method to solve the governing differential equation of plates using the Galerkin method. Symbolic algebra software is extensively used to perform necessary calculations. In this thesis, the lateral deflection of a plate is expressed in a series of polynomials each of which satisfies the given homogeneous boundary conditions. The coefficients of these polynomials are found out by the Galerkin method. Symbolic algebra software works best while handling necessary algebra to generate admissible polynomials and build required matrices for solving for the coefficients.This thesis demonstrates the calculation of the lateral load for different plates under different …

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Spreading, Solidification And Remelting Behavior Of Liquid Metal Droplets Sequentially Impinging Onto A Metal Substrate, Lister Manohar Pinto Aug 2005

Spreading, Solidification And Remelting Behavior Of Liquid Metal Droplets Sequentially Impinging Onto A Metal Substrate, Lister Manohar Pinto

Mechanical and Aerospace Engineering Theses - Archive

The fluid dynamics and simultaneous solidification of two successive molten metal droplets impacting a flat substrate is investigated numerically. The primary objective is to investigate the effects of initial droplet and substrate temperature, and the latent heat of substrate material, on the spreading, solidification and remelting of molten tin droplets impacting a substrate of the same material. A robust fluid-flow solver that is capable of modeling rapidly deforming free surfaces involving a moving phase-change boundary is employed in the study. The Navier-Stokes equations are solved using a finite volume formulation. A two-step projection method is used to solve for incompressible …

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Design Optimization And Synthesis Of Manipulators Based On Various Manipulation Indices, Sandipak Bagchi Aug 2005

Design Optimization And Synthesis Of Manipulators Based On Various Manipulation Indices, Sandipak Bagchi

Mechanical and Aerospace Engineering Theses - Archive

Design optimization of serial manipulators involves striking a balance between an appropriate joint angle and exact link lengths. The optimization technique used in this thesis uses a unique algorithm that optimizes the joint angle through an Inverse Kinematics program. The synthesis problem involves setting up an accurate design length so as to reach a set of given target points inside the workspace without any singularity. The optimization process based on task specification focuses on the maximization of manipulability index, the objective function subjected to link length and joint angle constraints. The results obtained were plotted and animated to visualize the …

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Piezoelectric Micropump For Drug Delivery Application, Miteshkumar Sureshchandra Joshi Aug 2005

Piezoelectric Micropump For Drug Delivery Application, Miteshkumar Sureshchandra Joshi

Material Science and Engineering Theses - Archive

Bending type actuators providing high displacement (~1mm) with low blocking force (~0.5N) and the stack actuators providing low displacement (~1m) with high blocking force (~1kN) represent the extreme ends of the current piezoelectric actuation technology. In the intermediate range there is deficiency of the actuator designs that provide high displacement with high blocking force in low frequency range of ~2 kHz. This thesis addresses this issue and describes a metal-ceramic actuator design that exhibits high displacement with high blocking force. The structure consist of a piezoelectric bar poled along the length and metal caps were attached to the two opposite …

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Comparison Of Adsorption Capacities Of Nanoadsorbents With Conventional Activated Carbon For Volatile Organic Compounds, Namrata Baburao Deshmukh Aug 2005

Comparison Of Adsorption Capacities Of Nanoadsorbents With Conventional Activated Carbon For Volatile Organic Compounds, Namrata Baburao Deshmukh

Civil Engineering Theses - Archive

This research explores the potential for using single wall carbon nanohorns (SWNHs) for adsorption of volatile organic compounds (VOCs) categorized as hazardous air pollutants and which contribute to ground level ozone smog formation. It also compares the adsorption capacity of conventional activated carbon and carbon nanohorns. Carbon nanoadsorbents, with at least one dimension on the nanometer scale, can possess advantages over traditional activated carbon adsorbents in terms of binding energies or interaction potentials for physisorption. Nanotubes and nanohorns both have excellent adsorption properties due to high-energy adsorption sites in their interior (internal pores) and in the region between adjacent nanotubes/nanohorns …

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Field And Experimental Studies To Assess The Performance Of Stabilized Expansive Clay, Gautham S. Pillappa Aug 2005

Field And Experimental Studies To Assess The Performance Of Stabilized Expansive Clay, Gautham S. Pillappa

Civil Engineering Theses - Archive

A vast majority of the expansive soils are montmorillonite-rich clays, over consolidated clays and shales. The swell and shrinkage movements of expansive soil cause considerable damage to structures such as buildings and pavements. This damage can be attributed to moisture fluctuations caused by seasonal variations. Volumetric changes typically appear in the form of cracks which will lead to the softening and vertical heaving in subsoils. Both softening and vertical expansion induce damage to overlying structures. Certain soils rich with sulfates exhibit swell and heaving even after treatment with stabilizers. The present research project was conducted at the University of Texas …

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Evaluation Of Texas Cone Penetrometer Test To Predict Undrained Shear Strength Of Clays, Hariharan Vasudevan Aug 2005

Evaluation Of Texas Cone Penetrometer Test To Predict Undrained Shear Strength Of Clays, Hariharan Vasudevan

Civil Engineering Theses - Archive

The cone penetration test used in Texas is termed as Texas cone penetrometer (TCP), which works on dynamic principles similar to those of SPT, i.e. a hammer is used to drive the cone device for a preset depth of penetration of 12 inches. Results are typically reported in the form of N12 values. Correlations between N12 and soil strength properties are currently used by the TxDOT to determine in situ strength properties of soils prior to any infrastructure design. A research study was initiated to evaluate the existing shear strength predicting correlations used by TxDOT and its applicability for soils …

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Water Damage Evaluation Of Concrete Infrastructure, Roshan Shakya Aug 2005

Water Damage Evaluation Of Concrete Infrastructure, Roshan Shakya

Civil Engineering Theses - Archive

This study presents an experimental program to evaluate the effect of a special waterproofing material, International Chem-Crete Pavix (CCP), on the durability of concrete. The experimental program identified the concrete mix design commonly used for pavement and other infrastructure as set by Texas Department of Transportation (TXDOT). The tests conducted include the water absorption and air void (ASTM C 642), freeze-thaw (ASTM C 666), chloride penetration (ASTM C 1202), and petrographic (ASTM C 457) test. The tests were performed on both cored and laboratory treated and untreated specimens. The absorption test was performed on the concrete specimens with water cement …

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Impacts Of Signal Synchronization On Vehicular Emissions - An On-Board Measurement Case Study, Rupangi Munshi Aug 2005

Impacts Of Signal Synchronization On Vehicular Emissions - An On-Board Measurement Case Study, Rupangi Munshi

Civil Engineering Theses - Archive

Nearly 56% of total nitrogen oxide (NOx) emissions are produced by mobile sources. Transportation and air quality managers at the state and regional level have the responsibility of developing and evaluating Transportation Control Measures (TCMs) and Transportation Improvement Plans (TIPs) to improve air quality of the region. Signal synchronization is considered to be an effective TCM to reduce corridor congestion and maintain air quality in the region. This research was carried to determine the impacts of signal synchronization on real-world, on-road emissions. A portable instrument, OBS-1300 manufactured by Horiba Instruments Inc., was used to measure on-road tailpipe emissions of NOx …

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Development Of Finite Element Method-Based Model Equations For Hollow Tapered Poles, Jiwon Jung Aug 2005

Development Of Finite Element Method-Based Model Equations For Hollow Tapered Poles, Jiwon Jung

Civil Engineering Dissertations - Archive

This study presents the development of three-parameter load-deflection models for steel and FRP poles commonly used to support closed circuit television cameras. An experimental investigation is carried out to obtain static load-deflection characteristics of tapered octagonal steel cross section and circular FRP cross section poles. Numerical results generated from three-dimensional isoparametric finite element model (FEM) considering coupled nonlinear algorithms for material, geometric, contact, and pre-tensioning effects are compared with those obtained experimentally. Eight-node elsto-plastic solid element is employed to model the pole, end-plate, bolts, concrete base, and laboratory reaction floor. The laboratory reaction floor is modeled with a thick plate …

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Analysis Of The Dynamics Of Vasomotion Using Laser Doppler Flow, Shruthi Raj Aug 2005

Analysis Of The Dynamics Of Vasomotion Using Laser Doppler Flow, Shruthi Raj

Bioengineering Theses - Archive

Vasomotion is a phenomenon caused by changes in the diameters of blood vessels. It is due to the contractile activity of small arteries and arterioles resulting in periodic changes of blood flow in the skin. These flow variations in the arteries are reflected by the Laser Doppler Flowmeter. The goal of the skin blood flow (blood perfusion) study is to establish a method to analyze and quantify the pattern of vasomotion as detected using Laser Doppler Flow (LDF). Spectral analysis of the LDF signal reveals the presence of periodic components in the vascular system. The study involves twelve subjects of …

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Performance Evaluation Of Bamboo Reinforced Concrete Beams, Leena Khare Aug 2005

Performance Evaluation Of Bamboo Reinforced Concrete Beams, Leena Khare

Civil Engineering Theses - Archive

This study presents the evaluation of the feasibility of the use of bamboo as a potential reinforcement in concrete structural members. To achieve this objective a series of tensile tests on three types of bamboo Solid; Moso; and Tonkin; were conducted to obtain their constitutive relation. Also, four-point bending tests on concrete beams reinforced with bamboo were performed to identify their behavior compared to steel reinforced concrete members. Tensile tests specimens were prepared by cutting the bamboo typically in 1/2 in (13 mm) wide strips of 9 to 12 in (228 mm to 305 mm) in length. In order to …

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Performance And Check-Out Verification Testing Of A New True Triaxial Apparatus Using Partially Saturated Silty Sand, Jae Hyun Park Aug 2005

Performance And Check-Out Verification Testing Of A New True Triaxial Apparatus Using Partially Saturated Silty Sand, Jae Hyun Park

Civil Engineering Theses - Archive

A stress-controlled, flexible boundary, true triaxial (cubical) testing apparatus has been developed to test 3-inch cubical specimen of partially saturated soil under different moisture contents and for a wide range of multiaxial stress paths. A series of HC, CTC, TC, TE, and SS tests were conducted in order to perform a thorough performance and check-out verification testing of the newly developed device by investigating the multiaxial stress-strain response of partially saturated silty sand specimens artificially prepared in the laboratory. The development of the apparatus, specimen preparation process, test procedure, and the corresponding validation of its suitability for testing partially saturated …

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Modeling And Characterization Of A Fabry Perot Pressure Sensor, Shruthika Prasanna Aug 2005

Modeling And Characterization Of A Fabry Perot Pressure Sensor, Shruthika Prasanna

Electrical Engineering Theses - Archive

Fabry-Perot interferometers (FPIs) have been used as sensing elements for pressure transducers in many applications. Most of the current FPI pressure sensors measure amplitude changes of the reflected signals from a deformable diaphragm. A new technique to design an FPI pressure sensor has been proposed in this thesis. The proposed methodology aims to maximize the sensitivity by measuring frequency shifts and optimize the dimensions of the sensors for various materials and applications. The sensor diaphragm is built directly on the end surface of an optical fiber with a sacrificial layer introducing the required FPI cavity height. The resulting sensor detects …

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Physics Based Time-Frequency Analysis To Reduce Multi-Bounce And Clutter In Radar Imaging, Anilkumar Kollipara Aug 2005

Physics Based Time-Frequency Analysis To Reduce Multi-Bounce And Clutter In Radar Imaging, Anilkumar Kollipara

Electrical Engineering Theses - Archive

The concept of time-frequency analysis of the scattered far field data from multiple targets is presented. The scattered data from the target is collected using a mono-static antenna configuration. The hardware system and the data acquisition system used in the process are discussed in detail. The results obtained using the ISAR imaging algorithm are presented and the effect of different non-point and dispersive scattering phenomena on these images are discussed. A physics based time-frequency analysis using wavelets is done on this scattered data to reduce the inter-target interactions and thereby produce cleaner images of the target under consideration. The results …

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Optical Amplifiers For 10 Gb/S Wdm Recirculating Loop Testbed, Sravanthi Thotakura Aug 2005

Optical Amplifiers For 10 Gb/S Wdm Recirculating Loop Testbed, Sravanthi Thotakura

Electrical Engineering Theses - Archive

This Master's thesis deals with building experimental setup for characterization of novel nonlinear optical devices for fiber communication. The first part of the thesis deals with the description of the theoretical basis for operation of a particular type of such nonlinear optical devices, namely a parametric amplifier. Document includes deriving and solving the equations for parametric amplification in optical fiber when signal, idler and pump beams are linearly co-polarized. We consider both non-degenerate and degenerate pump cases for arbitrary phase mismatch. In the second part of the thesis we present the design and experimental implementation of electrical interface between commercial …

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Time Synchronization In Network-Centric Sensor Networks, Sejal D. Raje Aug 2005

Time Synchronization In Network-Centric Sensor Networks, Sejal D. Raje

Electrical Engineering Theses - Archive

Time synchronization is a crucial component of infrastructure for wireless sensor networks (WSN). Most applications of WSNs make extensive use of time synchronization, for accurate timestamping of events, coordinate activities of the network, data fusion, object tracking or TDMA scheduling. The unique requirements of sensor networks in terms of precision, lifetime, energy and scope of the synchronization achieved, calls for design of new synchronization methods for WSNs. In this thesis, we describe the design of three novel techniques for achieving synchronization in network centric scenario of sensor networks: sequential least squares, Kalman filter and fuzzy logic systems. The strength of …

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Collision Response For Virtual Laparoscopic Surgery, Jitesh Devidas Butala Aug 2005

Collision Response For Virtual Laparoscopic Surgery, Jitesh Devidas Butala

Electrical Engineering Theses - Archive

During laparoscopic surgery the surgeon operates inside the abdomen guided by the 2D imagery of the operating area. This image is obtained via a camera inserted through a small incision. Laparoscopic surgery, in contrast to open surgery, results in low pain and recovery time for the patient. However, the surgeons have some difficulty, as the training required for this type of surgery is more intense and rigorous than that for conventional open surgery. Hence, surgical trainers for laparoscopic surgery are important. The main difference in the different types of surgical trainers is the degree to which the actual environment of …

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Structure & Decision In Mobile Wireless Sensor Networks, Prasanna Mohan Ballal Aug 2005

Structure & Decision In Mobile Wireless Sensor Networks, Prasanna Mohan Ballal

Electrical Engineering Theses - Archive

This work concerns the development of a novel structure of Discrete Event Controller (DEC) for mobile wireless sensor networks consisting of mobile robots and stationary wireless sensing nodes known as Unattended Ground Sensors (UGS). These are the three contributions: 1. Decision-making systems such as Fuzzy Logic and Dempster Shafer Theory for sensor fusion are implemented. 2. Decision-making is used for a special case of routing of resources for multiple tasks performed by different resources. 3. The DEC was actually implemented in the Mobile Wireless Sensor Networks lab at Automation & Robotics Research Institute. This work was supported by ARO grant …

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Vascular Stent Analysis, Tre Raymond Welch Aug 2005

Vascular Stent Analysis, Tre Raymond Welch

Bioengineering Theses - Archive

It is important for cardiologist to understand the stresses and strains the stent experiences during deployment. We created a 3-D model of the coiled stent which is exported into ANSYS creating the finite element model. The stent material is Poly-L-Lactic Acid (PLLA) fiber with a Young's modulus of 7043(MPa) and a Poisson's ratio of 0.35. A nonlinear material analysis simulates the material behavior through plastic deformation during expansion from 1(atm) to 14(atm). The von Mises stresses, principal stresses, and principal strains are analyzed to determine the yielding of the PLLA fiber. Also, the effect of different material properties including Young's …

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Near Infrared Spectroscopy: A Study Of Cerebral Hemodynamics During Breathholding And Development Of A System For Hot Flash Measurement, Vikrant Sharma Aug 2005

Near Infrared Spectroscopy: A Study Of Cerebral Hemodynamics During Breathholding And Development Of A System For Hot Flash Measurement, Vikrant Sharma

Bioengineering Theses - Archive

Near Infrared (NIR) spectroscopy and imaging has become popular in research fields for the past 2-3 decades. My research focuses on the continuous wave near infrared imaging technique. The work consists of two main parts. In the first part, an existing commercial system, an LEDI (Light Emitting Diode Imager), is used to study the cerebral hemodynamics during breath holding. The aim was to evaluate the ability of an LED-based continuous wave imager to capture changes in hemodynamics occurring inside the skull induced by breath holding. The study involved 15 human subjects. It was found that the total hemoglobin concentration (in …

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Dynamic Modeling Of Cerebral Blood Flow Autoregulation Using Arx And Windkessel Models, Piyush Gehalot Aug 2005

Dynamic Modeling Of Cerebral Blood Flow Autoregulation Using Arx And Windkessel Models, Piyush Gehalot

Bioengineering Theses - Archive

Linear lumped parameter models like ARX and Windkessel models are simple, easy to solve, and find their application in real time modeling. The present study is focused on employing single input single output ARX and Windkessel models to beat-to-beat mean arterial blood pressure (MABP, mmHg) considered as input to the model, and cerebral blood flow velocity (CBFV, cm/sec) considered as output of the model. For some models and modeling methodologies, the data consisted of cerebral perfusion pressure (CPP, mmHg, estimated from MABP) and CBFV. The data was measured from 10 healthy normal subjects while the subjects performed Valsalva maneuver with …

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Ccfss News Fall 2005, Wei-Wen Yu Center For Cold-Formed Steel Structures Aug 2005

Ccfss News Fall 2005, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Newsletters (1999 - 2008)

No abstract provided.

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Key Seismic Design Parameters: Steel And Wood Light-Frame Shear Walls, Coheen & Associates Structural Engineering Aug 2005

Key Seismic Design Parameters: Steel And Wood Light-Frame Shear Walls, Coheen & Associates Structural Engineering

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

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The Global Positioning System, Timothy S. Stombaugh, Doug Mclaren, Benjamin K. Koostra Aug 2005

The Global Positioning System, Timothy S. Stombaugh, Doug Mclaren, Benjamin K. Koostra

Agricultural Engineering Extension Publications

The Global Positioning System (GPS) is quickly becoming part of the fabric of everyday life. Beyond recreational activities such as boating and backpacking, GPS receivers are becoming a very important tool to such industries as agriculture, transportation, and surveying. Very soon, every cell phone will incorporate GPS technology to aid first responders in answering emergency calls.

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Piezoelectric Analysis For Hetrogeneous Medium, Solmaz Torabi Aug 2005

Piezoelectric Analysis For Hetrogeneous Medium, Solmaz Torabi

Material Science and Engineering Theses - Archive

In the recent years, several types of piezocomposites have been fabricated since they have provided material properties superior to conventional piezoelectric materials. In order to design these composites, it is essential to find the elastic and electric fields for their different parts, as well as the effective properties of the composite. In the present study, the analytical approach based on the extension of Eshelby's theory in piezoelectricity and the numerical approach based on FEM modeling and ANSYS software have been used to find these elastic and electric fields inside the piezoceramic inhomogeneity for two different piezocomposite according to their connectivity, …

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Nonlinear H2/H∞ Constrained Feedback Control: A Practical Design Approach Using Neural Networks, Murad Abu-Khalaf Aug 2005

Nonlinear H2/H∞ Constrained Feedback Control: A Practical Design Approach Using Neural Networks, Murad Abu-Khalaf

Electrical Engineering Dissertations - Archive

In this research, practical methods for the design of H2 and H8 optimal state feedback controllers for constrained input systems are proposed. The dynamic programming principle is used along with special quasi-norms to derive the structure of both the saturated H2 and H8 optimal controllers in feedback strategy form. The resulting Hamilton-Jacobi-Bellman (HJB) and Hamilton-Jacobi-Isaacs (HJI) equations are derived respectively. It is shown that introducing quasi-norms on the constrained input in the performance functional allows unconstrained minimization of the Hamiltonian of the corresponding optimal control problem. Moreover, it is shown how to obtain nearly optimal minimum-time and constrained state controllers …

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Low Phase Noise Voltage-Controlled Oscillator Design, Zhipeng Zhu Aug 2005

Low Phase Noise Voltage-Controlled Oscillator Design, Zhipeng Zhu

Electrical Engineering Dissertations - Archive

Two kinds of voltage-controlled oscillators (VCO) - active inductor based VCO and LC cross-coupled VCO - are studied in this work. Although the phase noise performance is not competitive, the proposed active inductor based VCO provide an alternative method to VCO design with very small chip area and large tuning range. The measurement shows a test oscillator based on active inductor topology successfully oscillates near 530MHz band. The phase noise of the widely used LC cross-coupled VCO is extensively investigated in this work. Under the widely used power dissipation and chip area constraints, a novel optimization procedure in LC oscillator …

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Power Management Integrated Circuits Design, Functionality Analysis And Applications, Zheng Li Aug 2005

Power Management Integrated Circuits Design, Functionality Analysis And Applications, Zheng Li

Electrical Engineering Dissertations - Archive

Power management is playing a significant role in modern electronics. Good power management is especially important for portable devices that rely on batteries. By smartly managing how the power is directed to different components of a system, e.g., reducing power to components that are not being used, the efficiency as well as the battery lifetime can be doubled or tripled. There exists a large family of integrated circuits (IC) that are used for power management, e.g., linear regulators, switching regulators, power controllers, hot swap controllers, etc. The voltage reference is one of the key components in this family. For high …

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The Operation Platform Recommendation For The Deregulated Utility Industry In Thailand, Chai Chompoo-Inwai Aug 2005

The Operation Platform Recommendation For The Deregulated Utility Industry In Thailand, Chai Chompoo-Inwai

Electrical Engineering Dissertations - Archive

Transmission Congestion Management (TCM) plays a significant role in power system operation under today deregulated environment. It has two major functions of an apparatus to keep power system running within acceptable security limits, and of a tool allocating financial obligation to market participants then paying back to transmission grid investors. TCM issue has been widely debating during a past decade, until now, it is still an opened issue extensively discussed in the current structure of competitive environment. In the United State, there are existing two successful stories of TCM under different operation schemes, the former is PJM with Nodal Congestion …

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