A rate-dependent algebraic stress model for turbulence

Based on the stress transport model, a rate-dependent algebraic expression for the Reynolds stress tensor is developed. It is shown that the new model includes the normal stress effects and exhibits viscoelastic behavior. Furthermore, it is compatible with recently developed improved models of turbulence. The model is also consistent with the limiting behavior of turbulence in the inertial sublayer and is capable of predicting secondary flows in noncircular ducts. The TEACH code is modified according to the requirements of the rate-dependent model and is used to predict turbulent flow fields in a channel and behind a backward-facing step. The predicted results are compared with the available experimental data and those obtained from the standard k-ε and algebraic stress models. It is shown that the predictions of the new model are in better agreements with the experimental data.     

Studies on synthetic inorganic ion exchangers-V: preparation, properties and ion-exchange behaviour of amorphous and crystalline thorium tungstate

Amorphous and crystalline thorium tungstate have been prepared by mixing 0.1M thorium nitrate and 0.1M sodium tungstate under different conditions. The physico-chemical properties, chemical stability, composition, TGA, DTA, X-ray, infrared absorption and ion-exchange behaviour of thorium-tungstate are reported and discussed. Distribution coefficients of metal ions on thorium tungstate have been determined at pH 2-3 and 5.5-6.5. Selective ion-exchange separations of bismuth and mercury from other metal ions have been achieved on a column of thorium tungstate.     

Synthesis of Calix

The formation of p-tert-butylcalix[4]arene mono-, bis-, tris-, and tetrakistriflates 3, 2, 4, and 5, respectively, and their respective reactions, under typical Pd-catalyzed carbonylative, Suzuki-Miyaura coupling, or deoxygenation conditions are described. A novel, nonsolvent-derived 1:1 clathrate (6) of benzophenone and 3 was formed from the palladium-catalyzed carbonylative reaction of phenylboronic acid and 2. The X-ray crystal structure of this first nonsolvent-derived clathrate of a calix[4]arene derivative is reported. Another 1:1 clathrate of triethylamine and 3 was formed during the attempted Pd-catalyzed deoxygenation of 2.     

Monte Carlo simulation of three-dimensional dilute Ising model

A multispin coding program for site-diluted Ising models on large simple cubic lattices is described in detail. The spontaneous magnetization is computed as a function of temperature, and the critical temperature as a function of concentration is found to agree well with the data of Marro et al.⁽⁴⁾ and Landau⁽³⁾ for smaller systems.The first successful epsilon expansion seems to be by D. E. Khmelnitskii,ZhETF 68:1960 (1975), English translationSov. Phys. JETP 41:981 (1975); for numerical estimates see K. E. Newman and E. K. Riedel,Phys. Rev. H25:264 (1982), for experiments see R. J. Birgenau, R. A. Cowley, G. Shirane and H. Yoshizawa,J. Stat. Phys. 34:817 (1984).     

Separation of Variables for a Lattice Integrable System and the Inverse Problem

We investigate the relation between the local variables of a discrete integrable lattice system and the corresponding separation variables, derived from the associated spectral curve. In particular, we have shown how the inverse transformation from the separation variables to the discrete lattice variables may be factorized as a sequence of canonical transformations.     

Identification of \mathrm{\ensuremath J^{\pi} = 19/2^+} and \mathrm{\ensuremath 23/2^+} isomeric states in 127Sb

The nucleus $\ensuremath {\rm ^{127}Sb}$ , which is on the neutron-rich periphery of the $\ensuremath \beta$ -stability region, has been populated in complex nuclear reactions involving deep-inelastic and fusion-fission processes with $\ensuremath {\rm {}^{136}Xe}$ beams incident on thick targets. The previously known isomer at 2325 keV in $\ensuremath {\rm {}^{127}Sb}$ has been assigned spin and parity $\ensuremath 23/2^+$ , based on the measured $\ensuremath \gamma$ - $\ensuremath \gamma$ angular correlations and total internal conversion coefficients. The half-life has been determined to be 234(12) ns, somewhat longer than the value reported previously. The 2194 keV state has been assigned $\ensuremath J^{\pi} = 19/2^+$ and identified as an isomer with $\ensuremath T_{1/2} = 14(1) {\rm ns}$ , decaying by two $\ensuremath E2$ branches. The observed level energies and transition strengths are compared with the predictions of a shell model calculation. Two $\ensuremath 15/2^+$ states have been identified close in energy, and their properties are discussed in terms of mixing between vibrational and three-quasiparticle configurations.     

An ab-initio Investigation: The Physical Properties of ScIr2 Superconductor

Physics of the Solid State - Using ab initio technique the physical properties of ScIr2 superconductor have been investigated with Tc 1.03 K with a MgCu2-type structure. We have carried out the...