Tehran, Iran

The Iran University of Science and Technology is a research institution and university of engineering and science in Iran, offering both undergraduate and postgraduate studies. Located on Hengam Street in the Narmak neighborhood in northeast Tehran, IUST and its surrounding communities provide a cultural and recreational environment suited to the work of a major research institution. The university consistently ranks among Iran's top three technical universities. Wikipedia.

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A new, efficient, one-pot multicomponent reaction for the synthesis of diazepine derivatives in excellent yields is described. The reactions of various 1,2-diamines, terminal alkynes, and an isocyanide take place in the presence of a catalytic amount of magnetically recoverable silica-supported superparamagnetic Fe3O4 nanoparticles in ethanol (as a green reaction medium) at ambient temperature. © 2013 Elsevier Ltd. All rights reserved.

In this research, a new protocol for the one-pot multicomponent synthesis of diazepine derivatives using a 1,2-diamine, a linear or cyclic ketone, and an isocyanide in the presence of a catalytic amount of silica-supported iron oxide (Fe 3O 4/SiO 2) nanoparticles at ambient temperature in excellent yields is described. © 2012 Elsevier Ltd. All rights reserved.

Samavati V.,Iran University of Science and Technology
Carbohydrate Polymers | Year: 2013

Crude polysaccharide extraction from the Iranian Abelmoschus esculentus was performed using water decoction. Response surface methodology (RSM), based on a five level, four variable central composite rotatable design (CCRD), was employed to obtain the best possible combination of extraction time (X 1: 0.5-6.5 h), extraction temperature (X2: 80-100 °C), number of extraction (X3: 1-5), and water to the raw material ratio (X4: 4-28) for maximum polysaccharide extraction. The experimental data obtained were fitted to a second-order polynomial equation using multiple regression analysis and also analyzed by appropriate statistical methods (ANOVA). The optimum extraction conditions were as follows: extraction time of 4.94 h, extraction temperature of 94.97 °C, number of extraction of 4, and the ratio of water to raw material of 21.74. Under these conditions, the experimental yield was 16.895 ± 0.29%, which is well in close agreement with the value predicted by the model 16.916%. © 2013 Elsevier Ltd.

Soltani R.,Iran University of Science and Technology
International Journal of Industrial Engineering Computations | Year: 2014

The purpose of this paper is to discuss the state of the art on models and methods for reliability optimization problems (ROPs) including reliability allocation, redundancy allocation and reliability-redundancy allocation. There are literally few surveys for reviewing the literature of the ROPs. Tillman et al. (1980) classified the related papers by system structure, problem type, and solution methods, separately. In another work, Tzafestas (1980) reviewed system reliability optimization models and the optimization techniques. Yearout (1986) reviewed the literature related to standby redundancy. Kuo (2000) studied the system reliability optimization based on system structure and solution methods. Kuo and Prasad (2004) overviewed system reliability optimization methods. Later, Kuo (2007) reviewed recent advances in optimal reliability allocation problems. The present study adds to the previous literature surveys and focuses mainly on papers after year 2000 but with a quick review on the previous works so that the readers become familiar with the existing approaches. This research investigates the literature from system structure, system performance, uncertainty state and solution approach standpoints, simultaneously. © 2014 Growing Science Ltd. All rights reserved.

Khaburi D.A.,Iran University of Science and Technology
IEEE Transactions on Instrumentation and Measurement | Year: 2012

In this paper, a new resolver-to-digital conversion method is presented. This method is based on synchronous demodulation of resolver's output signals. A modified angle-tracking observer is proposed to extract the rotor angle in high speeds as well as in low speeds. An estimation algorithm, which is based on the sign and absolute values of sine and cosine of the rotor angle, is introduced to find an appropriate initial value for this observer. This method can be incorporated in a DSP-based motor drive system. The proposed method is simple and cost effective when an appropriate microcontroller is selected for motor control. This method has been successfully implemented in a DSP board. Several tests at different speeds and initial positions have been performed to evaluate the proposed method. © 2012 IEEE.

Shahriari M.,Iran University of Science and Technology | Farrokhi M.,Iran University of Science and Technology
IEEE Transactions on Industrial Electronics | Year: 2013

This paper presents an online method for the estimation of the state of health (SOH) of valve-regulated lead acid (VRLA) batteries. The proposed method is based on the state of charge (SOC) of the battery. The SOC is estimated using the extended Kalman filter and a neural-network model of the battery. Then, the SOH is estimated online based on the relationship between the SOC and the battery open-circuit voltage using fuzzy logic and the recursive least squares method. To obtain the open-circuit voltage while the battery is operating, the reflective charging process is employed. Experimental results show good estimation of the SOH of VRLA batteries. © 2012 IEEE.

Rafee Nekoo S.,Iran University of Science and Technology
ISA Transactions | Year: 2013

The state-dependent Riccati equation (SDRE), as a controller, has been introduced and implemented since the 90s. In this article, the other aspects of this controller are declared which shows the capability of this technique. First, a general case which has control nonlinearities and time varying weighting matrix Q is solved with three approaches: exact solution (ES), online control update (OCU) and power series approximation (PSA). The proposed PSA in this paper is able to deal with time varying or state-dependent Q in nonlinear systems. As a result of having the solution of nonlinear systems with complex Q containing constraints, using OCU and proposed PSA, a method is introduced to prevent the collision of an end-effector of a robot and an obstacle which shows the adaptability of the SDRE controller. Two examples to support the idea are presented and conferred. Supplementing constraints to the SDRE via matrix Q, this approach is named a modified SDRE. © 2012 ISA.

Alinejad H.,Iran University of Science and Technology
Physics of Plasmas | Year: 2012

The linear and nonlinear propagation of ion-acoustic waves are investigated in a magnetized electron-positron-ion (e-p-i) plasma with nonthermal electrons. In the linear regime, the propagation of two possible modes and their evolution are studied via a dispersion relation. In the cases of parallel and perpendicular propagation, it is shown that these two possible modes are always stable. Then, the Korteweg-de Vries equation describing the dynamics of ion-acoustic solitary waves is derived from a weakly nonlinear analysis. The influence on the solitary wave characteristics of relevant physical parameters such as nonthermal electrons, magnetic field, obliqueness, positron concentration, and temperature ratio is examined. It is observed that the increasing nonthermal electrons parameter makes the solitary structures much taller and narrower. Also, it is revealed that the magnetic field strength makes the solitary waves more spiky. The present investigation contributes to the physics of the nonlinear electrostatic ion-acoustic waves in space and laboratory e-p-i plasmas in which wave damping produces an electron tail. © 2012 American Institute of Physics.

Gandomi A.H.,University of Akron | Alavi A.H.,Iran University of Science and Technology
Communications in Nonlinear Science and Numerical Simulation | Year: 2012

In this paper, a novel biologically-inspired algorithm, namely krill herd (KH) is proposed for solving optimization tasks. The KH algorithm is based on the simulation of the herding behavior of krill individuals. The minimum distances of each individual krill from food and from highest density of the herd are considered as the objective function for the krill movement. The time-dependent position of the krill individuals is formulated by three main factors: (i) movement induced by the presence of other individuals (ii) foraging activity, and (iii) random diffusion. For more precise modeling of the krill behavior, two adaptive genetic operators are added to the algorithm. The proposed method is verified using several benchmark problems commonly used in the area of optimization. Further, the KH algorithm is compared with eight well-known methods in the literature. The KH algorithm is capable of efficiently solving a wide range of benchmark optimization problems and outperforms the exciting algorithms. © 2012.

Mousavi G. S.M.,Iran University of Science and Technology
International Journal of Electrical Power and Energy Systems | Year: 2012

This paper focuses on dynamic modeling, simulation, control and energy management in an isolated integrated power generation system consisting of a 315 kW offshore wind turbine, a 175 kW tidal turbine, a 290 kW microturbine, and a 3.27 kAh lead acid battery storage. A first, due to efficient and economical utilization of the renewable energy resources, optimal sizing of the hybrid system is accomplished based on economic analysis using genetic algorithms. A model of power-consumption for a microturbine is obtained using least square estimation algorithm based on capstone™ company data and is suggested for implementing at economic analysis. For extraction of maximum energy from a variable speed wind turbine, a developed Lyapunov model reference adaptive feedback linearization method accompanied by an indirect space vector control is applied. Because of more reliability, more fuel flexibility, less environmental pollution, less noise generation and less power fluctuation in comparison with a diesel generator, a microturbine integrated with battery storage is suggested as a back up for this system. A supervisory controller is designed for energy management between the maximum energy captured from the wind turbine and consumed energies of the load, dump load, energy of the battery based on state of charge and generated energy by the microturbine. Dynamic modeling and simulation are fulfilled using MATLAB Simulink™7.2. © 2012 Elsevier Ltd. All rights reserved.

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