Kashan, Iran
Kashan, Iran

The University of Kashan, located in the city of Kashan in Iran, 230 kilometers south of the capital of Tehran. Educating an estimated 6,000 students in many different fields including engineering, physics, mathematics, chemistry, art, and humanities. Wikipedia.

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Mousavi-Kamazani M.,University of Kashan | Salavati-Niasari M.,University of Kashan
Composites Part B: Engineering | Year: 2014

Ag2S-AgInS2 nanocomposites, with the aid of [Ag(HSal)] and InCl3 as starting reagents, have been successfully synthesized by a microwave process from propylene glycol solution. Besides, the effects of preparation parameters such as irradiation time, solvents and sulfur source on the morphology and particle size of products were studied by SEM images. The synthesis procedure is novel, simple and uses less toxic reagents. The prepared Ag2S-AgInS2 nanostructures were characterized extensively by means of X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared (IR) spectrum, photoluminescence (PL) spectroscopy. The fill factor (FF), open circuit voltage (Voc), and short circuit current (Isc) were obtained by I-V characterization. © 2013 Elsevier Ltd. All rights reserved.

Mahmoodi M.,University of Kashan
International Journal of Thermal Sciences | Year: 2011

The present paper focuses on problem of free convection fluid flow and heat transfer of Cu-water nanofluid inside L-shaped cavities. The governing equations are discretized using the finite volume method while the SIMPLER algorithm is employed to couple velocity and pressure fields. Using the developed code, the effects of the Rayleigh number, the aspect ratio of the L-shaped cavity, and the volume fraction of the Cu nanoparticles on the flow and thermal fields and heat transfer inside the cavity are investigated. The obtained results show that the average Nusselt number for all rage of cavity aspect ratio increases with increase in the Rayleigh number and the solid volume fraction of the nanofluid. Also the Rayleigh number in which transition from conduction to convection occurs postpones with decreasing the aspect ratio of cavity. Moreover it is found that the rate of heat transfer increases with decreasing the aspect ratio of the cavity. © 2011 Elsevier Masson SAS. All rights reserved.

Mahmoodi M.,University of Kashan
International Journal of Thermal Sciences | Year: 2011

In the present paper, free convection fluid flow and heat transfer of various water based nanofluids in a square cavity with an inside thin heater has been investigated numerically. The left and right walls of the cavity are maintained at constant temperature Tc, while its top and bottom walls are insulated. A thin heater with the temperature of Th (T h > Tc) is located inside the cavity which its location and length is varying. The governing equations were discretized using the finite volume method and SIMPLER algorithm. Using the developed code, a parametric study was undertaken, and the effects of pertinent parameters, such as, Rayleigh number, the position and location of the heater, the volume fraction of the nanoparticles, and various types of the nanofluids on the fluid flow and heat transfer inside the cavity were investigated. It was observed from the results that at low Rayleigh numbers the horizontal positioned heater have higher Nusselt number compared to the vertical positioned heater while at high Rayleigh numbers the position of the heater does not affect the heat transfer rate. For a horizontal heater when it is located in lower half of the cavity, more heat transfer occurs compared to the case of heater located in upper half of the cavity. Moreover, it was found that at high Rayleigh numbers, the Ag-water nanofluid is more effective to enhance the heat transfer rate while at low Rayleigh numbers the type of nanofluids does not affect the heat transfer rate. © 2011 Elsevier Masson SAS. All rights reserved.

Fath-Tabar G.H.,University of Kashan
Match | Year: 2011

In this paper, some bounds for the first and second Zagreb indices of graphs are presented. A new graph invariant, named third Zagreb index, is introduced. Some mathematical properties of this new graph invariant are also presehted.

Mohandes F.,University of Kashan | Salavati-Niasari M.,University of Kashan
Ultrasonics Sonochemistry | Year: 2013

In this investigation, a facile sonochemical route has been developed for the preparation of silver vanadium oxide (SVO) micro/nanorods by using silver salicylate and ammonium metavanadate as silver and vanadate precursor, respectively. Here, silver salicylate, [Ag(HSal)], is introduced as a new silver precursor to fabricate AgVO 3 nanorods. The effect of numerous solvents and surfactants on the morphology and sonochemical formation mechanism of AgVO 3 nanorods was studied. AgVO 3 nanorods were characterized by SEM and TEM images, XRD patterns, FT-IR, XPS, and EDS spectroscopy. SEM, TEM, and XRD results showed that AgO nanoparticles were formed onto AgVO 3 nanorods in the presence of ethanol, cyclohexanol, dimethylsulfoxide (DMSO), and acetone. By using polyethylene glycol (PEG-6000) and N,N-dimethylformamide (DMF) as organic additives, the thickness of AgVO 3 nanorods decreased. © 2012 Elsevier B.V. All rights reserved.

Tahghighi H.,University of Kashan
Earthquake Engineering and Structural Dynamics | Year: 2011

Unique to the near-source region of a large earthquake is the occurrence of strong impulsive ground motion and surface faulting referred to as 'fling-step' motion. The objective of this study is to synthesize broad-band time histories over a wide range of frequencies by characterizing rupture directivity and fling effects from the comprehensive strong motion database of the near-fault Chi-Chi event. To aid in the generation of these special types of ground motions, a hybrid modeling technique is introduced based on the stochastic finite-fault radiation method and an efficient analytical approach to incorporate the observed low-frequency features in the records close to the ruptured fault. The results show that the overall agreement among the developed hybrid methodology and recorded waveforms and response spectra is quite satisfying. A brief discussion on the design of infrastructures near seismic fault is also included. © 2011 John Wiley & Sons, Ltd.

Copper(II) complexes with 15- and 16-membered diaza dioxa Schiff-base macrocyclic ligands "[Cu(R[15 or 16]N2O2)]2+ (R = Et, Pr, Ph, Ch)" were entrapped in the nanopores of zeolite-Y by a three-step process in the liquid phase: (i) exchange of Cu(II) ions with NaY in water solution, (ii) reaction of Cu(II)-NaY with excess 1,3-bis(2-carboxyaldehydephenoxy)propane (O2O2) in methanol, [(1,3-bis(2-carboxyaldehydephenoxy)propane)copper]2+@NaY, [Cu(O2O2)]2+@NaY (iii) template synthesis of [Cu(O2O2)]2+@NaY with diamine. The obtained new complex nanoparticles entrapped in the nanopores of zeolite Y have been characterized by elemental analysis FT-IR, XPS, DRS, UV-vis spectroscopic techniques, molar conductance, magnetic moment data, XRD and nitrogen adsorption. Analysis of data indicates all of the complexes have been encapsulated within nanopores without affecting the zeolite framework structure. © 2009 Elsevier B.V. All rights reserved.

Khorasanizadeh H.,University of Kashan | Mohammadi K.,University of Kashan
Energy | Year: 2013

In this study, by using long-term global solar radiation data and other meteorological parameters, 11 empirical models taken from the literature were tested for prediction of monthly mean daily global solar radiation over six major cities of Iran, named Isfahan, Karaj, Mashhad, Shiraz, Tabriz and Tehran. The models are from 3 categories: (1) Only function of sunshine duration; (2) Function of sunshine duration as well as relative humidity and ambient temperature; (3) Independent of sunshine duration and function of relative humidity, ambient temperature and its maximum and minimum. The models were established using statistical regression technique and their accuracies evaluated using the statistical indicators of mean percentage error (MPE), mean bias error (MBE) and root mean square error (RMSE); hence the best model in each category was recognized. Although, 5 out of the 6 nominated cities fell in climatic classification of BSk, it was not possible to introduce a single model even for the cities having the same climate type. However, for all of the cities the best model was either from categories (1) or (2). In line with increased tendency toward installation of solar systems in Iran, the proposed models are useful for simulations and incorporation in design procedures. © 2012 Elsevier Ltd.

Rahimi M.,University of Kashan
Renewable and Sustainable Energy Reviews | Year: 2014

This paper studies the dynamic behavior of doubly fed induction generators (DFIGs) modeled with the stator flux orientation regarding rotor- and grid-side converter control strategies. The investigations include modal and sensitivity analysis, and using them to identify and characterize the instability mode, stator dynamics analysis, and time domain simulations. The paper first deals with the modal analysis of the DFIG for different control strategies and operating conditions. Then the dynamic and transient performance of the DFIG under voltage dips and large disturbances are investigated, and the effects of rotor and grid-filter control strategies on the DFIG transient behavior are examined. Increasing the rotor and grid-filter closed loop bandwidths, rotor current active damping, and compensation of back-emf voltages can improve the rotor and grid-filter dynamics, decrease tracking error and limit the rotor current transients. However they can lead to poorly stator modes and deteriorate the DFIG transient performance. Thus, appropriate selection of rotor controller parameters has an important effect on the DFIG transient performance, and consequently on the future interconnected power system. © 2014 Elsevier Ltd.

Modeling of desorption kinetics plays an important role for better understanding of this phenomena. In the present work the kinetics of solute desorption at the solid/solution interface has been studied by statistical rate theory (SRT) when the system is close to equilibrium. It is demonstrated that, for desorption, a pseudo-first-order equation can be derived from the SRT equation when the system is close to equilibrium. On the basis of numerically generated points (t; q) by the SRT equation, it is shown that it is not possible to apply the pseudo-first-order equation for modeling of whole kinetic desorption data. The results of numerical analysis are in good agreement with our theoretical derivation of the pseudo-first-order equation for desorption systems close to equilibrium. Finally, the results of the present theoretical study were confirmed by analysis of two experimental systems. © 2011 American Chemical Society.

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