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Power Capacity (power + capacity)

Distribution by Scientific Domains

Engineering	60%

Selected Abstracts

Power generation expansion planning with emission control: a nonlinear model and a GA-based heuristic approach

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 2 2006
Jiraporn Sirikum
Abstract This paper presents an application of genetic algorithms (GA) for solving the long-term power generation expansion planning (PGEP) problem, a highly constrained nonlinear discrete optimization problem. The problem is formulated into a mixed integer nonlinear programming (MINLP) program that determines the most economical investment plan for additional thermal power generating units over a planning horizon, subject to the requirements of power demands, power capacities, loss of load probability (LOLP) levels, locations, and environmental limitations. Computational results show that the GA-based heuristic method can solve the PGEP problem effectively and more efficiently at a significant saving in runtime, when compared with a commercial optimization package. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Optimal allocation of distributed generation and reactive sources considering tap positions of voltage regulators as control variables

EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 3 2007
Mohamad Esmail Hamedani Golshan
Abstract In this paper, by defining and solving an optimization problem, amount of distributed generators (DGs) and reactive power sources (RSs) in selected buses of a distribution system are computed to make up a given total of distributed generation for minimizing losses, line loadings, and total required reactive power capacity. The formulated problem is a combinatorial problem, therefore Tabu search algorithm is applied for solving the optimization problem. Results of solving the optimization problem for a radial 33-bus distribution system and a meshed 6-bus system are presented. When using less amount of reactive capacity, regarding tap positions of voltage regulators as control variables has considerable role in loss reduction and improvement of voltage profile. In the case of meshed systems, including line loadings in the cost function can significantly change results of solving the optimization problem such as amount of the required reactive capacity and how to assign DGs and RSs to the selected buses. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Experimental and numerical studies on dynamic crack growth in layered slate rock under wedge impact loads: part II , non-plane strain problem

FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 10 2007
M. R. ALAM
ABSTRACT Dynamic crack propagation in non-plane strain (or 3D) slate blocks under wedge impact loads was investigated numerically in this part of the paper. A parabolic-shaped crack trajectory was taken into consideration to model the crack propagation in slate blocks for analyzing the impact splitting of layered slate rock. Major and minor axes of the parabola were determined from the condition of equal mode I stress intensity factors (SIFs) along the crack front. Mode I SIFs were determined for experimental breaking loads for each increment of crack growth in a manner similar to that mentioned in part I of this paper. These values were compared with the plane strain material fracture toughness value obtained from experimental studies and very good agreement was obtained between them, for the case of actual load applied on the specimen. Numerical analysis of a field problem, i.e., separation of a large-sized slate slab from the rock strata in a slate quarry using wedge impacting, was also carried out in this paper. It can be observed that a large magnitude of load is required to break large-sized slate blocks; but this load is applied through a number of smaller load-capacity actuators-in-parallel, requiring large power capacity for the hydraulic pumps. However, this required power could be reduced considerably if the load applied on the line of hydraulic actuators is cascaded across the (line of) actuators (starting from centrally placed actuators) with a small time delay (equal to the initial crushing time in slate rock). [source]

Experimental optimization of the 2nd loop configuration for feedforward amplifiers in terms of their efficiency and linearity

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2006
Sung-Chan Jung
Abstract In this paper, we report the results of the experimental optimization of the 2nd -loop configuration for feedforward amplifiers in terms of their efficiency and linearity. We consider two parameters in the 2nd -loop of a feedforward amplifier: (i) the size ratio between the main and error amplifiers and (ii) the coupling factor of the error signal coupler. Experiments are performed using a multicarrier down-link WCDMA signal under various configurations. The measured data, which are normalized with respect to the overall power capacity of the main and error amplifiers, show that, among the different 2nd -loop configurations, the best compromised efficiency (13.4%) at a given adjacent channel leakage ratio (ACLR) level (,50 dBc) is observed for a size ratio of around 3.0 and a coupling factor of around 7.2 dB. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 617,621, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21425 [source]

Vernacular Discourse and the Epistemic Dimension of Public Opinion

COMMUNICATION THEORY, Issue 4 2007
Gerard A. Hauser
Habermas argues that the epistemic dimension of a democracy resides in public opinion. This paper argues that a deliberative model of public opinion needs to take into account exchanges among ordinary citizens that underwrite public opinion and are a major source of the political public sphere's unruliness. Second, it argues that when we examine how ordinary citizens make arguments about public problems that intersect their lives, there is evidence that their norms of reasoning, standards of evidence, and modes of argumentation challenge the presuppositions and rationality of authority. Finally, it argues that although the power of media moguls is not to be discounted, the clock is ticking. Internet communication has opened new avenues for information and participation that can elude corporate power's capacity to control the game. [source]