Showing papers by "King Fahd University of Petroleum and Minerals published in 1999"
TL;DR: In this article, the authors extensively focused on energy and environmental impacts only, and discussed energy utilization and its major environmental impacts from the standpoint of sustainable development, including anticipated patterns of future energy use and subsequent environmental issues.
314 citations
TL;DR: In this paper, a comprehensive discussion of the future of energy use and the consequent environmental impacts in terms of acid precipitation, stratospheric ozone depletion and the greenhouse effect is presented.
313 citations
TL;DR: In this article, the problem of selecting the parameters of power system stabilizers which simultaneously stabilize this set of plants is converted to a simple optimization problem which is solved by a genetic algorithm with an eigenvalue-based objective function.
Abstract: This paper demonstrates the use of genetic algorithms for the simultaneous stabilization of multimachine power systems over a wide range of operating conditions via single-setting power system stabilizers. The power system operating at various conditions is treated as a finite set of plants. The problem of selecting the parameters of power system stabilizers which simultaneously stabilize this set of plants is converted to a simple optimization problem which is solved by a genetic algorithm with an eigenvalue-based objective function. Two objective functions are presented, allowing the selection of the stabilizer parameters to shift some of the closed-loop eigenvalues to the left-hand side of a vertical line in the complex s-plane, or to a wedge-shape sector in the complex s-plane. The effectiveness of the suggested technique in damping local and inter-area modes of oscillations in multimachine power systems is verified through eigenvalue analysis and simulation results.
275 citations
TL;DR: In this paper, a new algorithm based on integrating genetic algorithms, tabu search and simulated annealing methods to solve the unit commitment problem is presented, which is coded as a mix between binary and decimal representation.
Abstract: This paper presents a new algorithm based on integrating genetic algorithms, tabu search and simulated annealing methods to solve the unit commitment problem. The core of the proposed algorithm is based on genetic algorithms. Tabu search is used to generate new population members in the reproduction phase of the genetic algorithm. A simulated annealing method is used to accelerate the convergence of the genetic algorithm by applying the simulated annealing test for all the population members. A new implementation of the genetic algorithm is introduced. The genetic algorithm solution is coded as a mix between binary and decimal representation. The fitness function is constructed from the total operating cost of the generating units without penalty terms. In the tabu search part of the proposed algorithm, a simple short-term memory procedure is used to counter the danger of entrapment at a local optimum, and the premature convergence of the genetic algorithm. A simple cooling schedule has been implemented to apply the simulated annealing test in the algorithm. Numerical results showed the superiority of the solutions obtained compared to genetic algorithms, tabu search and simulated annealing methods, and to two exact algorithms.
274 citations
TL;DR: In this article, the role of management accounting in the construction of a strategic partnership is highlighted together with the need to develop costing and performance measurement technologies that can be understood and respected by both senior managers and non-accountants involved in the procurement process.
256 citations
TL;DR: In this article, a survey of the recent research studies in this important field is presented, which contains 336 references which are classified according to their applications and a brief theory and history of piezoelectricity.
Abstract: Due to their special characteristics, piezoelectric materials can be used in distributed behavior sensing and control of flexible structures. These materials are usually incorporated with the precision sensing and control of highly adaptive intelligent structures. Many theoretical, numerical, and experimental research activities treating piezoelectricity in sensing and control of various flexible structures have been carried out over the last decade. This survey article aims at collecting the recent research studies in this important field. It contains 336 references which are classified according to their applications. A brief theory and history of piezoelectricity is also presented.
225 citations
TL;DR: In this paper, the rheological, physical, and chemical properties of asphalts procured from Ras Tanura, Riyadh, Kuwait, and Bahrain refineries were evaluated.
200 citations
TL;DR: This paper determines optimal reduction in the procurement lead time duration for some stochastic inventory models, jointly with the optimal ordering decisions, and develops algorithms for solving these models.
193 citations
TL;DR: In this article, the concept of exergy analysis and the linkages between exergy and environmental impact are discussed, and several issues regarding the exergies of waste emissions are addressed Exergy is a measure of the degree of disequilibrium between a substance and its environment.
Abstract: Recently, significant attention has been directed towards the use of exergy analysis in the assessment of thermal and other industrial processes and their environmental impacts since exergy analysis is an effective tool both for achieving efficient energy utilization with minimum (or zero) environmental impact and for understanding environmental issues In this study, the concepts of exergy analysis and the linkages between exergy and environmental impact are discussed, and several issues regarding the exergies of waste emissions are addressed Exergy is a measure of the degree of disequilibrium between a substance and its environment The relations between several measures of environmental impact potential and exergy are investigated by comparing current methods used to assess the environmental impact potential of waste emissions and the exergy associated with those emissions A case study is presented, to highlight the information revealed using exergy, in which the measures of environmental impact potential considered are the Ontario Ministry of Environment's schedule of industrial air emission limits, and two methods of assessing the environmental costs for air emissions resulting from the combustion of three common fossil fuels: coal, oil and natural gas Copyright © 1999 John Wiley & Sons, Ltd
190 citations
TL;DR: The ANN model is used to forecast the energy requirements of an electric utility and is then compared to time series models, revealing that the ANN produces results that are close to the actual data.
162 citations
TL;DR: In this article, the authors investigated the optimum size of battery storage capacity for hybrid (wind+diesel) energy conversion systems at the solar radiation and meteorological monitoring station, Dhahran (26°C 32′ N, 50° 13′ E).
TL;DR: In this paper, an optimization procedure of a hybrid photovoltaic wind energy system is presented which can be used to satisfy the requirements of a given load distribution, and an analysis is applied to satisfy a constant load of 5 kW required for cathodic protection in offshore platforms.
TL;DR: The results of a study which investigates the relationships between end-users' attitudes and PC utilization among knowledge workers in the context of Saudi Arabia suggest that PC utilization is determined by individual attitudes, personal characteristics,such as PC experience, facilitating conditions, such as PC access and social factors.
TL;DR: In this article, the authors present a survey research to investigate three components of delay in the construction of water and sewage works in Saudi Arabia: the frequency of delayed projects, the extent of delay, and the responsibility for delay.
TL;DR: In this article, a tabu search (TS) based power system stabilizer (PSS) was proposed to damp out the local and the interarea modes of oscillations and work effectively over a wide range of loading conditions and system parameter variations.
TL;DR: In this article, the chemical properties of a commercial grade Saudi Arabian asphalt procured from Ras Tanura refinery were evaluated using a rolling thin film oven (RTFO) and a pressurized aging vessel (PAV) to simulate the laboratory aging of this asphalt.
TL;DR: In this article, an integrated model for joint optimization of the economic production quantity, the economic design of x¯-control chart, and the optimal maintenance level was developed for a deteriorating process where the in-control period follows a general probability distribution with increasing hazard rate.
Abstract: In this paper, we develop an integrated model for the joint optimization of the economic production quantity, the economic design of x¯-control chart, and the optimal maintenance level. This is done for a deteriorating process where the in-control period follows a general probability distribution with increasing hazard rate. In the proposed model, Preventive Maintenance (PM) activities reduce the shift rate to the out-of-control state proportional to the PM level. Compared to the case with no PM, the extra cost of maintenance results in lower quality control cost which may lead to lower overall expected cost. These issues are illustrated using an example of a Weibull shock model with an increasing hazard rate.
TL;DR: In this paper, a current-mode sinusoidal oscillator circuit using a single four-terminal floating nullor and eight passive elements is presented. But the proposed circuits use grounded capacitors and enjoy the independent grounded-element control of the frequency and condition of oscillation.
Abstract: New current-mode sinusoidal oscillator circuits are presented. The proposed circuits use single four-terminal floating nullor and, at most, eight passive elements. Two of the oscillator circuits use grounded capacitors and enjoy the independent grounded-element control of the frequency of oscillation and the condition of oscillation. Experimental results are included.
TL;DR: In this article, the authors investigated the entropy generation and pumping power required for a laminar viscous flow in a duct subjected to constant heat flux and the temperature dependence of the viscosity is taken into consideration.
Abstract: Entropy generation and pumping power required for a laminar viscous flow in a duct subjected to constant heat flux has been investigated. The temperature dependence of the viscosity is taken into consideration. The ratio of pumping power to total heat flux decreases considerably and entropy generation increases along the duct length for viscous fluids. Therefore, it is shown that an optimum duct length may be obtained which minimizes total energy losses due to both entropy generation and pumping power. For low heat-flux conditions, entropy generation due to viscous friction becomes dominant and the dependence of viscosity on temperature must be considered in order to determine entropy generation accurately.
TL;DR: In this paper, the capacitance multipliers and a frequency-dependent negative-resistance (FDNR) were shown to be tunable by adjusting the bias current of a plus-type current-controlled current-conveyor (CCCII+).
TL;DR: In this article, a comprehensive discussion of the evaluation and the selection of sensible and latent heat storage technologies, systems and applications in the field of solar energy is presented, along with some criteria, techniques, recommendations, checklists on the selection, implementation and operation of energy storage systems for the use of energy engineers, scientists and policy makers.
Abstract: Energy storage is one of the key technologies for energy conservation and therefore is of great practical importance. One of its main advantages is that it is best suited for solar thermal applications. This study deals with a comprehensive discussion of the evaluation and the selection of sensible and latent heat storage technologies, systems and applications in the field of solar energy. Several issues relating to energy storage are examined from the current perspective. In addition, some criteria, techniques, recommendations, checklists on the selection, implementation and operation of energy storage systems are provided for the use of energy engineers, scientists and policy makers. Copyright © 1999 John Wiley & Sons, Ltd.
TL;DR: In this article, a hybrid GA rule-based power system stabilizer (GRBPSS) was proposed to damp out the local as well as the interarea modes of oscillations.
Abstract: A hybrid genetic rule-based power system stabilizer (GRBPSS) is presented in this paper. The proposed approach uses genetic algorithms (GA) to search for optimal settings of rule-based power system stabilizer (RBPSS) parameters. Incorporation of GA in RBPSSs design will add an intelligent dimension to these stabilizers and significantly reduce the time consumed in the design process. It is shown in this paper that the performance of RBPSS can be improved significantly by incorporating a genetic-based learning mechanism. The performance of the proposed GRBPSS under different disturbances and loading conditions is investigated for a single machine infinite bus system and two multimachine power systems. The results show the superiority of the proposed GRBPSS as compared to both conventional lead-lag PSS (CPSS) and classical RBPSS. The capability of the proposed GRBPSS to damp out the local as well as the interarea modes of oscillations is also demonstrated.
TL;DR: In this article, the authors investigated the feasibility of using hybrid (wind+solar) energy conversion systems at a solar radiation and meteorological monitoring station in Saudi Arabia, where they reported the monthly variation of wind speed and solar radiation.
TL;DR: In this article, three new complexes involving nitronyl nitroxide and PhCOO-or N3- ligands have been synthesized and structurally and magnetically characterized.
Abstract: Three new complexes involving nitronyl nitroxide and PhCOO- or N3- ligands have been synthesized and structurally and magnetically characterized. These compounds are formulated as Mn(L)4(X)2·nH2O, L = 2-(p-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PNN) or 2-(p-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl (PN) and X = PhCOO- or N3-. Compound A [Mn(PNN)2(PhCOO)2(H2O)2] presents the following structural parameters: triclinic, space group P1 (No. 2), a = 6.859(1) A, b = 11.271(2) A, c = 13.978(6) A, α = 88.88(2)°, β = 89.38(2)°, γ = 78.28(2)°, Z = 1. The complex has a centrosymmetric distorted octahedral geometry in which the manganese ion is bound to two radical ligands through the nitrogen atom of the pyridine rings, two benzoate groups, and two water molecules. The two compounds B [Mn(PNN)4(N3)2] and C [Mn(PN)4(N3)2] are isostructural with the following structural parameters: B; triclinic, space group P1 (No. 2), a = 7.177(4) A, b = 13.767(3) A, c = 13.928(4) A, α = 90.20(2)°, β = 102.94...
TL;DR: In this paper, the authors defined the characteristic performance curves of vapor-compression refrigeration systems as a plot between the inverse coefficient of performance (1/COP) and inverse cooling capacity ( 1/Q evap ) of the system.
Abstract: The characteristic performance curves of vapor-compression refrigeration systems are defined as a plot between the inverse coefficient of performance (1/COP) and inverse cooling capacity (1/ Q evap ) of the system. Using the actual data of a simple vapor-compression system, performance curves of the system are obtained. The curves were found to be linear and this linear relation between 1/COP and 1/ Q evap is explained in the light of various losses of the system, resulting from the irreversibilities losses due to finite rate of heat transfer in the heat exchangers and non-isentropic compression and expansion in the compressor and expansion valve of the system, respectively. A finite-time thermodynamic model which simulates the working of an actual vapor-compression system is also developed. The model is used to study the performance of a variable-speed refrigeration system in which the evaporator capacity is varied by changing the mass-flow rate of the refrigerant, while keeping the inlet chilled-water temperature as constant. The model is also used for predicting an optimum distribution of heat-exchanger areas between the evaporator and condenser for a given total heat exchanger area. In addition, the effect of subcooling and superheating on the system performance is also investigated.
TL;DR: In this paper, the authors evaluate the TCT in a dynamic context to determine how accurately it measures the pace of technological progress and find that the trend in TCT changed abruptly from gradually increasing (slowing in cycle time) to steadily decreasing (speeding up in cycle times) following the discovery of high-temperature superconductors.
Abstract: The technology cycle time indicator (TCT) is a new measure of technological progress. The TCT is the median age of the patents cited on the front page of a patent document. The measure assumes that the more recent the age of the cited patents, the more quickly one generation of inventions is replacing another. The main purpose of the study was to evaluate the TCT in a dynamic context to determine how accurately it measures the pace of technological progress. This study found the trend in TCT changed abruptly from gradually increasing (slowing in cycle time) to steadily decreasing (speeding up in cycle time) following the discovery of high-temperature superconductors. The methodology prescribed in this study could potentially be used in assessing the pace of progress for different technologies or different nations in the same technology.
TL;DR: Fluorescence and absorption spectra of 10-4 M thymine in aqueous solutions at different pH values are reported at room temperature in this article, where the shape of the fluorescence spectrum is found to change when the excitation wavelength is varied.
Abstract: Fluorescence and absorption spectra of 10-4 M thymine in aqueous solutions at different pH values are reported at room temperature. The shape of the fluorescence spectrum is found to change when the excitation wavelength is varied. The absorption spectra for the aqueous pH 4−8 thymine solutions in the range 240−300 nm are believed to include the diketo tautomer T1 and the enol−keto tautomer T2. Steady-state fluorescence spectra and ab initio calculations support the existence of these neutral species in their ground state. The lifetimes of the excited states of the T1 and T2 tautomers are 0.72 and 3.87 ns, respectively. Aqueous thymine solutions with pH values below pH 3 contain a protonated enol−keto form of T2 in addition to the major diketo-tautomer T1 in its neutral form. The lifetime of the protonated enol−keto form is 4.2 ns. On the other hand, thymine solutions with pH values above pH 8 contain mixtures of the neutral forms of T1 and T2 as well as their monoanioic forms. However, aqueous thymine so...
TL;DR: In this article, the authors exploit the nonlinear mapping capabilities of radial basis function networks (RBFNs) in estimating line loading and bus voltage of a bulk power system following a contingency.
Abstract: Radial basis function networks (RBFNs) are used for contingency evaluation of bulk power system. The motivation behind this work is to exploit the nonlinear mapping capabilities of RBFN in estimating line loading and bus voltage of a bulk power system following a contingency. Unlike most of the available neural networks based techniques, the proposed method utilizes the potential of RBFN in planning studies. The performance of the RBFN is compared with a standard AC load flow algorithm.
TL;DR: The quaternary ammonium salt, N, N -diallyl- N -carboethoxymethyl- Nethylammonium chloride (7), has been synthesised in excellent yield as mentioned in this paper.
TL;DR: In this paper, a new algorithm based on integrating the use of genetic algorithms and tabu search methods to solve the unit commitment problem is presented, which is mainly based on genetic algorithms, which incorporates Tabu search method to generate new population members in the reproduction phase of the genetic algorithm.