Yehia Badr

Abstract Free convection over a vertical rectangular duct filled with porous matrix with variable viscosity and variable thermal conductivity is studied in this paper. We consider the two-dimensional steady laminar flow and Brinkman–Forchheimer extended Darcy model to define the porous medium. Using the appropriate variables the basic governing equations are transformed to non-dimensional governing equations. The fluid viscosity is assumed to vary exponentially with temperature whereas the thermal conductivity is assumed to vary linearly with temperature. One of the vertical walls of the duct is cooled with constant temperature while the other wall is heated to constant but different temperature. The governing coupled nonlinear momentum and energy equations are solved numerically using finite difference method. The effect of pertinent parameters such as variable viscosity, variable thermal conductivity, Darcy number, inertial parameter, Grashof number, Brinkman number and aspect ratio on the velocity, temperature, volumetric flow rate, shear stress and heat transfer are discussed.

Abstract Cyproheptadine hydrochloride (CYP HCl) {4-(5H-dibenzo[a,d]-cyclohepten-5-ylidene)-1-methylpiperidine hydrochloride} is a first-generation antihistamine with additional anticholinergic, antiserotonergic, and local-anesthetic properties. The geometry optimization, Mulliken atomic charges and wavenumber and intensity of the vibrational bands of all of the possible modes of \{CYP\} \{HCl\} have been calculated using ab initio Hartree–Fock (HF) and density functional theory (DFT) employing the \{B3LYP\} functional with the 6-311G(d,p) basis set. We have compared the calculated İR\} and Raman wavenumbers with experimental data. Quantum-chemical calculations of the geometrical structure, energies, and molecular electrostatic potential and \{NBO\} analysis of \{CYP\} \{HCl\} have been performed using the B3LYP/6-311G(d,p) method. The electric dipole moment (μ), static polarizability (α) and the first hyperpolarizability (β) values of the title compound have been computed using \{HF\} and \{DFT\} methods. The study reveals that the antihistaminic pharmacological property of \{CYP\} \{HCl\} has a large β value and, hence, may in general have potential applications in the development of non-linear optical materials. The experimental and calculated results for \{CYP\} \{HCl\} have also been compared with those for mianserin HCl.