Showing papers by "Iran University of Science and Technology published in 2006"
TL;DR: The ability of DLLME technique in the extraction of other organic compounds such as organochlorine pesticides, organophosphorus pesticides and substituted benzene compounds were studied.
2,959 citations
TL;DR: Under the optimum conditions, the enrichment factors and extraction recoveries were high and ranged between 789-1070 and 78.9-107%, respectively, while the linear range was wide and limit of detections were very low and were between 3 to 20 pg/mL for most of the analytes.
826 citations
21 Jun 2006
TL;DR: A comprehensive study of challenges in vehicle ad hoc networking and the research trends in this area is provided.
Abstract: Vehicular Ad hoc Network (VANET), a subclass of mobile Ad Hoc networks (MANETs), is a promising approach for future intelligent transportation system (ITS). These networks have no fixed infrastructure and instead rely on the vehicles themselves to provide network functionality. However, due to mobility constraints, driver behavior, and high mobility, VANETs exhibit characteristics that are dramatically different from many generic MANETs. This article provides a comprehensive study of challenges in these networks, which we concentrate on the problems and proposed solutions. Then we outline current state of the research and future perspectives. With this article, readers can have a more thorough understanding of vehicle ad hoc networking and the research trends in this area.
561 citations
TL;DR: Results have shown that DEMATEL method can be an efficient, complementary and confident approach for reprioritization of failure modes in a FMEA and can cover some of inherently shortcomings of conventional Risk Priority Number method and like.
368 citations
TL;DR: The honey-bees mating optimization algorithm (HBMO) is presented and tested with few benchmark examples consisting of highly non-linear constrained and/or unconstrained real-valued mathematical models and results obtained are promising and compare well with the results of other well-known heuristic approaches.
Abstract: Over the last decade, evolutionary and meta-heuristic algorithms have been extensively used as search and optimization tools in various problem domains, including science, commerce, and engineering. Their broad applicability, ease of use, and global perspective may be considered as the primary reason for their success. The honey-bees mating process may also be considered as a typical swarm-based approach to optimization, in which the search algorithm is inspired by the process of real honey-bees mating. In this paper, the honey-bees mating optimization algorithm (HBMO) is presented and tested with few benchmark examples consisting of highly non-linear constrained and/or unconstrained real-valued mathematical models. The performance of the algorithm is quite comparable with the results of the well-developed genetic algorithm. The HBMO algorithm is also applied to the operation of a single reservoir with 60 periods with the objective of minimizing the total square deviation from target demands. Results obtained are promising and compare well with the results of other well-known heuristic approaches.
340 citations
TL;DR: Single drop microextraction (SDME) with modified 1.00 microl microsyringe is developed, followed by gas chromatography with flame photometric detector (GC-FPD) for determination of 13 organophosphorus pesticides (OPPs) in water samples.
321 citations
01 Jul 2006
TL;DR: This paper describes the application of the genetic algorithm for the optimization of the control parameters in parallel hybrid electric vehicles (HEV) based on an electric assist control strategy (EACS) so as to minimize the vehicle engine fuel consumption and emissions.
Abstract: This paper describes the application of the genetic algorithm for the optimization of the control parameters in parallel hybrid electric vehicles (HEV). The HEV control strategy is the algorithm according to which energy is produced, used, and saved. Therefore, optimal management of the energy components is a key element for the success of a HEV. In this study, based on an electric assist control strategy (EACS), the fitness function is defined so as to minimize the vehicle engine fuel consumption (FC) and emissions. The driving performance requirements are then considered as constraints. In addition, in order to reduce the number of the decision variables, a new approach is used for the battery control parameters. Finally, the optimization process is performed over three different driving cycles including ECE-EUDC, FTP and TEH-CAR. The results from the computer simulation show the effectiveness of the approach and reduction in FC and emissions while ensuring that the vehicle performance is not sacrificed.
241 citations
15 Feb 2006-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, a series of mixed mode I/II fracture tests were conducted on polymethylmethacrylate (PMMA) in the full range from pure mode I to pure mode II using a semi-circular bend (SCB) specimen containing an edge crack.
Abstract: A series of mixed mode I/II fracture tests is conducted on polymethylmethacrylate (PMMA) in the full range from pure mode I to pure mode II using a semi-circular bend (SCB) specimen containing an edge crack. The fracture load and the path of crack growth are obtained from experiments for various crack angles. It is shown that the conventional mixed mode I/II fracture criteria such as the maximum tangential stress (MTS) criterion overestimate the fracture strength of PMMA when the SCB specimen is used for fracture tests, particularly for mode II dominant loading conditions. However, improved predictions of fracture load are achieved when a generalized MTS criterion is employed. While the path of crack growth is straight for pure mode I, it deviates significantly from the angle of fracture initiation for pure mode II and mode II dominant loading conditions. It is shown that the path of crack growth predicted by the generalized MTS criterion is also in a good agreement with the observed fracture path in the fractured SCB samples.
233 citations
TL;DR: In this paper, the lifetime prediction of a horizontal axis wind turbine composite blade is considered and load cases are identified, calculated and evaluated using a full 3D finite element method and the critical zone where fatigue failure begins is extracted.
200 citations
TL;DR: In this paper, a qualitative case study technique has been used for data collection to gain insights into the topic being investigated, and the extracted concepts can demonstrate critical success factors of KM system within organizations.
Abstract: Purpose – To date, critical success factors for design and implementing knowledge management (KM) system in a multi‐case study research have not been systematically investigated. Most of existing studies have derived their critical success factors from single company perspectives and have not considered all factors in an integrated way in a multi case study research. This paper is aimed to bridge this gap.Design/methodology/approach – A qualitative case study technique has been used in this paper for data collection to gain insights into the topic being investigated. For that, “grounded theory” research approach has been selected by which the collected data from real case studies (successful organizations in KM adoption) are categorized and analyzed through specific stages. The extracted concepts can demonstrate critical success factors of KM system within organizations.Findings – The overall results from the real case studies were positive, thus reflecting the appropriateness of the proposed critical suc...
197 citations
TL;DR: In this article, a numerical algorithm based on the method of least squares (MLS) is presented for the design and optimization of a Wilkinson power divider for arbitrary power division between its outputs in a specified frequency bandwidth incorporating source and load impedance matching.
Abstract: In this paper, a numerical algorithm based on the method of least squares (MLS) is presented for the design and optimization of a Wilkinson power divider for arbitrary power division between its outputs in a specified frequency bandwidth incorporating source and load impedance matching. At first, its transmission, admittance, and scattering matrices are determined successively by considering the dispersion and dissipation models of substrate and metallic strips. An error function is then constructed for the desired output power division, maximum level of isolation between them, and the least amount of reflected power. Minimization of the error function with respect to the widths and lengths of strips and values of resistors provides their optimum values. A procedure is provided for the initial design and determination of initial values of parameters of a Wilkinson power divider based on the method of even- and odd-mode analysis. The optimum design of the Wilkinson power divider by the proposed MLS procedure is validated by available full-wave analysis software and fabrication and measurement of two samples.
TL;DR: In this article, four different fiber reinforced composite plates are studied after being impacted by a standard drop weight with different impact energies and moments, and the damage zones are studied by ultra-sonic non-destructive inspection.
TL;DR: In this article, a modified maximum tangential stress criterion is used for calculating mode II fracture toughness in terms of mode I fracture toughness KIc, and the modified criterion provides very good predictions for experimental results.
TL;DR: The sorbent exhibited excellent stability and its sorption capacity under optimum conditions has been found to be 10mg of uranium per gram of sorbent, and the method was applied for the recovery and determination of uranium in different water samples.
TL;DR: In this paper, the performance of a proton exchange membrane fuel cell (PEMFC) under various operating conditions was investigated experimentally using dry and humidified hydrogen and oxygen as reactant and oxidant gases, respectively.
TL;DR: In this article, a multi-stage fuzzy proportional integral derivative (PID) type controller is proposed to solve the automatic generation control (AGC) problem in a deregulated power system that operates under deregulation based on the bilateral policy scheme.
TL;DR: A series of noble metal catalysts (Ru, Rh, Ir, Pt, and Pd) supported on alumina-stabilized magnesia (Spinel) were used to produce syngas by methane reforming with carbon dioxide as mentioned in this paper.
TL;DR: It is shown that the proposed model enables to establish routes to serve all given customers by the minimum number of vehicles and the maximum capacity used and the proposed heuristic can find good solutions in reasonable time.
TL;DR: A bi-objective model of RCPSP is presented, the first objective is makespan to be minimized, and the second one, a recently developed measure, is robustness maximization aimed at floating time maximization to make scheduling more reliable.
TL;DR: In this article, the upper and lower limits of life are estimated using the proposed life equations, where the upper life limit is obtained by assuming that the dominant cracking mechanism is Case A and the lower life limit, which is the case B, is derived from the amount of dissipated energy over life cycles.
TL;DR: A nonlinear artificial neural networks (ANN) controller based on μ-synthesis for solution the load frequency control (LFC) problem is proposed in this paper, which combines advantage of the ANN and μ-Synthesis control techniques to achieve the desired level of robust performance for all admissible uncertainties and leads to a flexible controller with relatively simple structure.
TL;DR: In this paper, a fuzzy logic proportional plus conventional integral controller is proposed for damping local modes and inter-area modes of oscillations in a multi-machine power system, which combines the advantages of a FLC and a conventional PI controller.
TL;DR: In this article, a series of fracture toughness tests have been conducted on a type of coarse grain marble and the average value of KIc for this marble was approximately about 1.12 MPa m showing a good agreement with those reported for similar coarse grain marbles.
Abstract: A series of fracture toughness tests have been conducted on a type of coarse grain marble. The tests were carried out either in pure mode I or in pure mode II conditions by using the cracked chevron notched Brazilian disc (CCNBD) specimen. A total number of 44 CCNBD specimens were tested, half in pure mode I and the rest in pure mode II, to obtain reliable values for mode I and mode II fracture toughness (KIc and KIIc) of the tested marble. The average value of KIc for this marble was approximately about 1.12 MPa m showing a good agreement with those reported for similar coarse grain marbles. The mode II fracture toughness was found to be 2.25 MPa m in average which is approximately twice the mode I fracture toughness. However, the conventional fracture criteria suggest that the mode I fracture toughness should be higher than the mode II fracture toughness, (KIc>KIIc). According to these criteria, the ratio of KIIc / KIc is a figure typically between 0.63 and 0.96. It is shown in this paper that enhanced mode II fracture toughness of CCNBD specimen could be due to the effects of highly negative T-stress when the specimen is subjected to mode II. It is also shown that an improved prediction for the ratio KIIc / KIc can be achieved when the effect of T-stress is taken into account.
TL;DR: In this paper, a unified fatigue life model based on the energy method is developed for unidirectional polymer composite laminates subjected to constant amplitude, tension-tension or compression-compression fatigue loading.
TL;DR: This paper has briefly discussed the problem of likelihood function formed for the parameter estimation of a three-parameter Weibull distribution and proposed a new approach based on the simulated algorithm to solve that.
TL;DR: This paper presents a Taylor-series expansion method for a second kind Fredholm integral equations system with smooth or weakly singular kernels that reduce the system of integral equations to a linear system of ordinary differential equation.
TL;DR: In this paper, a desiccant-based dehumidifying process is used to direct the air through an evaporative cooler, which could be either media-based or spray type.
TL;DR: In this article, Nanocrystalline zirconia powder with high surface area, pure tetragonal phase and mesoporous structure was prepared by a surfactant-assisted route by using Pluronic P123 block copolymer as the surfactants.
TL;DR: In this paper, a cool chamber wall spray dryer was used in order to decrease the probability of particles stickiness on the wall, and it was shown that an addition of 10% silicon dioxide and 20% maltodextrin (DE5) to lime juice is the optimum amount for a complete and successful drying of lime juice.
Abstract: One of the major problems in spray drying of fruit juices such as lime juice is stickiness and thermoplasticity of their compositions. Lime juice consists of invert sugars and citric acid, which have low glass transition temperatures. Due to this characteristic, the particles stick on the dryer wall upon their collision with it. As a result, drying of these materials is very difficult. In order to solve this problem, various percent of silicon dioxide and maltodextrin (DE5), based on total soluble solid content of lime juice, have been used to reach a suitable drying condition. A cool chamber wall spray dryer was used in this investigation in order to decrease the probability of particles stickiness on the wall. Our investigation revealed that an addition of 10% silicon dioxide and 20% maltodextrin (DE5) to lime juice is the optimum amount for a complete and successful drying of lime juice. Sampling of particles from different longitudinal distances in the dryer tower is carried out to find the particle m...
TL;DR: An experimental design was used to optimize plasmid purification from an alkaline lysate of Escherichia coli cells using PEG‐sodium citrate aqueous two‐phase systems (ATPS), and to evaluate the influence of pH, PEG molecular weight, tie line length, phase volume ratio, and lysATE load.
Abstract: An experimental design was used to optimize plasmid purification from an alkaline lysate of Escherichia coli cells using PEG-sodium citrate aqueous two-phase systems (ATIPS), and to evaluate the influence of pH, PEG molecular weight, tie line length, phase volume ratio, and lysate load. To build the mathematical model and minimize the number of experiments for the design parameters, response surface methodology (RMS) with an orthogonal rotatable central composite design was defined based on the conditions found for the highest purification by preliminary tests. The adequacy of the calculated models for the plasmid recovery and remaining RNA were confirmed by means of variance analysis and additional experiments. Analysis of contours of constant response as a function of pH, PEG molecular weight, tie line length, and cell lysate load for three different phase volume ratios revealed different effects of these five factors on the studied parameters. Plasmid recovery of 99% was predicted for a system with PEG 400, pH 6.9, tie line length of 38.7%, phase volume ratio of 1.5, and lysate load of 10% MO. Under these conditions the predicted RNA removal was 68%. (c) 2006 Wiley Periodicals, Inc. (Less)