Extending the applicability of the inexact Newton-HSS method for solving large systems of nonlinear equations

Numerical Algorithms - We revisit the study of the semi-local convergence of the inexact Newton-HSS method (INHSS) introduced by Amiri et al. (2018), for solving large systems of nonlinear...     

The effect of mass transfer on MHD free convective radiating flow over an impulsively started vertical plate embedded in a porous medium

The laminar convective heat and mass transfer flow of an incompressible, viscous, electrically conducting fluid over an impulsively started vertical plate with conduction-radiation embedded in a porous medium in presence of transverse magnetic eld has been studied. An exact solution is derived by solving the dimensionless governing coupled partial differential equations. As the equations are nonlinear, so Laplace transform technique is used to solve it. The eects of important physical parameters on the velocity, temperature, concentration, skin friction, Nusselt number and Sherwood number have been analyzed through graphs. The results of the present study agree well with the previous solutions obtained without mass transfer. After the consideration of mass transfer, some dierent results are noticed. Applications of the present study arise in material processing systems and different industries.     

Photophysical Investigations on Determination of Ionicity and Electronic Structures for the Non-covalent Complexes of Calix[4]resorcinarene with Fullerenes C<Subscript>60</Subscript> and C<Subscript>70</Subscript> in the Solution State

Ground state non-covalent interactions between a macrocyclic receptor, C-methylcalix[4]resorcinarene (1) and fullerenes (C₆₀ and C₇₀) have been studied in benzonitrile by an absorption spectrophotometric method. Absorption bands are located in the visible region due to the charge transfer (CT) transition between 1 and various electron acceptors (including fullerenes), namely, 2,3-dichloro-5,6-dicyano-p-benzoquinone, tetracyanoquinodimethane and p-chloranil. Utilizing the CT absorption bands, various important physicochemical parameters, including oscillator strength, resonance energy, transition dipole strength of all the acceptor-1 complexes and vertical ionization potential of 1 are determined. Job’s method of continuous variation reveals 1:1 stoichiometry between fullerenes and 1. The most fascinating feature of the present study is that 1 binds selectively to C₇₀ compared to C₆₀ as obtained from binding constant (K) data of C₆₀-1 (K_C60-1K_{\mathrm{C}60\mbox{-}\mathbf{1}}) and C₇₀-1 (K_C70-1K_{\mathrm{C}70\mbox{-}\mathbf{1}}) complexes, i.e., K_C60-1=190K_{\mathrm{C}60\mbox{-}\mathbf{1}}=190 dm³⋅mol⁻¹ and K_C70-1=5,800K_{\mathrm{C}70\mbox{-}\mathbf{1}}=5{,}800 dm³⋅mol⁻¹ and selectivity (K_C70-1 /K_C60-1 ) ∼30. Quantum chemical calculations based on hybrid density functional theory estimate the enthalpies of formation of the fullerene-1 complexes in vacuo and provide very good support for selectivity in the K values of the C₇₀ and C₆₀ complexes of 1. The exchange and correlation energies have been calculated using a hybrid DFT functional method. We have opted to use the hybrid DFT functional over the Hartree-Fock method, as it can account for correlation effects also. Molecular electrostatic potential map calculations give a clear picture on the electronic structures of the fullerene-1 complexes.     

Polymerization of acrylonitrile initiated by a manganese(III) acetate glycerol redox system

The kinetics of polymerization of acrylonitrile(AN) initiated by manganese(III) acetate in the presence of glycerol was investigated in the temperature range of 30–40°C. The effect of varying the concentrations of glycerol, sulfuric acid, acetic acid, metal ion, and monomer on the rate was studied. A suitable reaction scheme and rate expression have been proposed. Termination was mutual and was caused by the combination of two growing polymer radicals.     

Substituent effects in the reaction between acetophenones and polyacrylonitrile radicals

The reactivity of substituted acetophenones towards polyacrylonitrile radical has been correlated with Swain and Luptons field and resonance parameters inclusive of the unique positional weighting factors suggested by Williams and Norrington. From the sign and magnitude of the reaction dependent regression constants, the transition state has been found to be essentially ‘non-polar’ in character.     

Electrodeposition of CoWP film: V. Structural and morphological characterisations

CoWP films were electrochemically deposited on copper-coated silicon wafers from citrate electrolytes containing cobalt sulphate, sodium tungstate and sodium hypophosphite under various deposition conditions and characterisations of the films were carried out using various instrumental techniques. Composition analyses using XPS showed that the surfaces of the films contained large amounts of oxides and hydroxide of tungsten and cobalt, respectively. An AES depth-profile, however, revealed that the bulk of the films predominantly consisted of cobalt, tungsten and phosphorus. Microstructural analyses using XRD showed that, depending on the composition and/or deposition conditions, CoWP films could be amorphous, polycrystalline and crystalline with a strong preferred orientation. Amorphous films were obtained when deposited at higher applied potential and current density or the films contained high amount of phosphorus and/or tungsten, while films deposited by very low applied potential and current density were crystalline with a preferred orientation of [0 0 2] of hexagonal cobalt. SEM images showed that the films deposited from neutral or acidic baths at room temperature had typical spherical nodular structures, while the films deposited from basic solution or at elevated temperature had needle-like crystallites. The crystalline films were much rougher than the amorphous films.     

Estimation of the heat capacity of some uranium-rare earth mixed oxides from thermal expansion and vice versa

Estimation of the high temperature heat capacity (C _p) data from experimental high temperature thermal expansion (α _v) data and vice versa from the known values of the ratio (α_v/C _p) at low temperatures were carried out by assuming linear relationship of the ratio α _v /C _p with temperature (at T > θ _D). The assumption was examined using the known α _v and C _p values of single phase fluorite systems such as UO₂, ThO₂ and PuO₂. It was also examined using the known α _v and C _p of the mixed oxides (U_1?y La_y) O_2±x (y = 0.2, 0.4, 0.6 and 0.8). The estimated values of α _v and C _p are in good agreement with the experimental values within ±3%. Using the assumption the high temperature heat capacity data of (U_1?y Ce _y ) O₂ (y = 0.2, 0.8) and (U_1?y Gd _y ) O_2±x (y = 0.2, 0.5) were computed from the experimental high temperature α _v data.