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111.
Xi Gao Jia Yu Ricardo J.F.Portal Jean-Franois Dietiker Mehrdad Shahnam William A.Rogers 《Particuology》2022,(2):74-90
This article presents the development and validation of the Superquadric Discrete Element Method(SuperDEM) for non-spherical particle simulation using a superqu... 相似文献
112.
Javad Azizian Ali Varasteh Morady Khosrow Jadidi Morteza Mehrdad Yaghob Sarrafi 《合成通讯》2013,43(3):537-542
The title compounds have been obtained thermally and under microwave irradiation by condensation of isatin, aromatic amines and mercaptoacetic acid in good to excellent yields without isolating the imine intermediates. 相似文献
113.
Karim Mahnam Amir Sadeghi Mehrdad Mohammadpour Afshin Fassihi 《Monatshefte für Chemie / Chemical Monthly》2012,12(6):19-27
Abstract
The binding affinity of some novel 1,4-dihydropyridine-3,5-dicarboxamides to enoyl-ACP reductase (InhA) from M. tuberculosis was studied by the docking method. A molecular dynamics simulation lasting 230 ns in total was performed for 19 ligand–enzyme complexes to calculate the binding free energies of these ligands to the enzyme. All of the studied compounds stayed in the active site. An energetics analysis revealed that the van der Waals share is more important than electrostatic in binding of all ligands to the active site. 相似文献114.
Abbas Mehrdad 《Journal of solution chemistry》2012,41(5):766-776
In this work, the intrinsic viscosities of poly(vinyl pyrrolidone) with a molar mass of 58?kg?mol?1 were measured in water?Cdimethyl sulfoxide solutions at temperatures from (298.15 to 318.15)?K. The expansion factors of the polymer chains were calculated from the intrinsic viscosity data. The thermodynamic parameters (entropy of dilution parameter, the heat of dilution parameter, theta temperature, polymer?Csolvent interaction parameter and second osmotic virial coefficient) were derived by the temperature dependence of the polymer chain expansion factor. The thermodynamic parameters indicate that mixtures of water/dimethyl sulfoxide become poorer solvents for poly(vinyl pyrrolidone) as the temperature is increased. Also, the thermodynamic parameters indicate that water/dimethyl sulfoxide mixtures become better solvents for poly(vinyl pyrrolidone) by increasing the volume fractions of dimethyl sulfoxide. 相似文献
115.
Ling Miao Wei‐Tao Wu Nadine Aubry Mehrdad Massoudi 《Mathematical Methods in the Applied Sciences》2014,37(18):2840-2853
In this paper, we study the heat transfer in the fully developed flow of a viscoelastic fluid, a slag layer, down a vertical wall. A new constitutive relation for the stress tensor of this fluid is proposed, where the viscosity depends on the volume fraction, temperature, and shear rate. For the heat flux vector, we assume the Fourier's law of conduction with a constant thermal conductivity. The model is also capable of exhibiting normal stress effects. The governing equations are non‐dimensionalized and numerically solved to study the effects of various dimensionless parameters on the velocity, temperature, and volume fraction. The effect of the exponent in the Reynolds viscosity model is also discussed. The different cases of shear‐thinning and shear‐thickening, cooling and heating, are compared and discussed. The results indicate that the viscous dissipation and radiation (at the free surface) cause the temperature to be higher inside the flow domain. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
116.
As a viable alternative to the petrochemical polyols in polyurethanes (PUs), a new soybean oil‐based polyol (PSBO) with high functionality of hydroxyl groups and built‐in (preformed) urethane bonds was introduced. At first, a facile and improved method was developed for the transformation of epoxidized soybean oil (ESBO) to carbonated soybean oil (CSBO). Then ring‐opening reaction of carbonated oil with ethanolamine (ETA) led to the polyol. After characterization by conventional spectroscopic and analytical methods, PSBO was used for the formulation of novel one‐pack PU electroinsulating wire enamels. Tunable mechanical, thermal, and electrical properties for the final PUs were achieved by replacing 10 wt% of PSBO with poly(propylene glycol) (PPG) at different number average molecular weights of 725, 1000, 2000, 4000. Investigation of the results showed that these soy‐based PUs offer excellent thermal and electrical insulating properties. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
117.
Using a general expression for the second term in the density expansion of the hard core potentials, we obtained an analytical expression for the direct correlation function of the hard core double Yukawa potential. The results of this calculation using the proposed direct correlation function and its related radial distribution function through the Ornstein-Zernike equation show good agreements with those obtained by the computer simulation of the same model. 相似文献
118.
Mehrdad Lakestani Mehdi Dehghan Safar Irandoust-pakchin 《Communications in Nonlinear Science & Numerical Simulation》2012,17(3):1149-1162
Fractional calculus has been used to model physical and engineering processes that are found to be best described by fractional differential equations. For that reason we need a reliable and efficient technique for the solution of fractional differential equations. Here we construct the operational matrix of fractional derivative of order α in the Caputo sense using the linear B-spline functions. The main characteristic behind the approach using this technique is that it reduces such problems to those of solving a system of algebraic equations thus we can solve directly the problem. The method is applied to solve two types of fractional differential equations, linear and nonlinear. Illustrative examples are included to demonstrate the validity and applicability of the new technique presented in the current paper. 相似文献
119.
The main toxic compound found in false morel (Gyromitra esculenta) is acetaldehyde-N-methyl-N-formylhydrazone (gyromitrin). This paper describes a method of determining the total hydrazones content based on acid hydrolysis of gyromitrin and other related hydrazones in air-dried false morel followed by derivatisation of methylhydrazine with pentafluorobenzoyl chloride. The derivative, tris-pentafluorobenzoyl methylhydrazine (tris-PFB-MH) is analyzed by gas chromatography-mass spectrometry. The overall precision of the method is better than 10% (relative standard deviation) for 0.5 ng/microl methylhydrazine in solution. The minimum detectable concentration of methylhydrazine (tris-PFB-MH) by this method is estimated to be approximately 12 pg/microl, which is equal to 0.3 microg/g dry matter (DM) of false morel. 相似文献
120.
Hossein Farajollahi Mehrdad Farhoudi Hossein Shojaie 《International Journal of Theoretical Physics》2010,49(10):2558-2568
We study longstanding problem of cosmological clock in the context of Brans–Dicke theory of gravitation. We present the Hamiltonian
formulation of the theory for a class of spatially homogeneous cosmological models. Then, we show that formulation of the
Brans–Dicke theory in the Einstein frame allows how an identification of an appropriate cosmological time variable, as a function
of the scalar field in the theory, can be emerged in quantum cosmology. The classical and quantum results are applied to the
Friedmann–Robertson–Walker cosmological models. 相似文献