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The COSMO-RS model was used to screen potential ionic liquids for the separation of aqueous azeotropic mixtures 1-propanol + water and 2-propanol + water. A combination of 22 cations (involving imi...

The D -eigenvalues μ 1 , μ 2 , … , μ n of a graph G of order n are the eigenvalues of its distance matrix D and form the distance spectrum or D -spectrum of G denoted by S p e c D ( G ) . Let G 1 and G 2 be two regular graphs. The Indu–Bala product of G 1 and G 2 is denoted by G 1 ▾ G 2 and is obtained from two disjoint copies of the join G 1 ∨ G 2 of G 1 and G 2 by joining the corresponding vertices in the two copies of G 2 . In this paper we obtain the distance spectrum of G 1 ▾ G 2 in terms of the adjacency spectra of G 1 and G 2 . We use this result to obtain a new class of distance equienergetic graphs of diameter 3 . We also prove that the class of graphs K n ¯ ▾ K n + 1 ¯ has integral distance spectrum.

Electric field effects on FSLC films of p-pentyl cyano biphenyl (5CB) have been optically studied. Due to the initial alignment of the molecules, initially formed transition layers grow with increasing field and merge to form a linear wall at the middle of the sample. This linear wall splits into two disclinations at relatively high fields. But a sudden application of relatively high electric field results in the formation of closed metastable walls. The wall orientation shows interesting behaviour with the field frequency. At high field, the closed walls undergo distortion and division into two or more parts.

Studies of electric field-induced orientational effects are carried out on substrate-free nematic 8CB films, held between parallel electrodes and containing a peripheral-1/2 loop. The loop separates the birefringent boundary from the central homeotropic zone. Static and dynamic characteristics of the splay-bend layers contiguous to the electrodes are investigated by polarizing microscopy. A model based on director field symmetry is proposed to explain (a) the growth of the transition layers independently of the associated singularities and (b) the formation or otherwise of static solitons (Brochard-Leger walls). Linear dependence of the growth rate of transition layers on field strength is compared with a similar behaviour for line defects. Bifurcation of a soliton at elevated voltages into a pair of - 1/2 lines, through a non-pincement process, is described.

Nematic 8CB and MBBA slabs, with a homeotropic zone between two parallel -1/2 disclinations (and associated splay bend zones), are subject to an electric or magnetic field acting transversely to the disclinations. Optical microscopic study of the static and dynamic characteristics of the boundary zones is carried out for the first time. The growth rate of the zones is linear in field-strength. As the field is progressively elevated, the zones widen nonlinearly, and merge to form a splay-bend wall in the mid-region. At a high enough field, the homeotropic region is squeezed out of the wall and a pair of wedge disclinations forms in its place. One of these combines with a -1/2 line originally present in the field off state, forming a loop that progressively collapses.

An analysis of the solidification rates of binary mixture melts flowing as a thin film on a cold surface, useful in the separation or purification of eutectic mixtures, is presented. The analysis which incorporates the hydrodynamics of the falling film and the convective heat transfer at the melt/crystal interface was used to determine the average crystallization velocity. The effect of parameters such as Stefan number (subcooling), initial superheat and the melt loading rate on the average crystallization velocity was examined. Experiments were performed using three different binary organic mixtures at subeutectic compositions. The results of the theoretical and experimental studies showed good agreement validating the model. ? 1999 OPA (Overseas Publishers Association) N.V.

Four Thermotropic Liquid Crystalline (TLC) random copolyesters were prepared by direct polycondensation of two diols and oxaloyl chloride in o-dichlorobenzene solution. The structures of the repeating units of the synthesised polyesters were examined by FT-IR and PMR spectral data. The thermal transition temperatures were determined by differential scanning calorimetry. The LC behaviour of these polymers were studied by optical polarising microscopy in conjunction with WAXD studies. Three of these polyesters exhibited interesting biphase behaviour. The polyester containing 2,5-ditertiarybutylphenylene rings in the main chain exhibited discotic behaviour.

We screened 57 Sahiwal cattle (Bos indicus) and 53 Murrah, 19 Nili‐Ravi and 11 Egyptian buffaloes (Bubalus bubalis) to detect the polymorphisms at kappa‐casein (CSN3) gene using the polymerase chain reaction (PCR). CSN3 A and B alleles were identified by PCR‐RFLP using the restriction enzymes that detect the underlying nucleotide changes at codon 136 (TaqI) and at codon 148 (HindIII or HinfI) in cattle. The frequency of CSN3 B allele in the Sahiwal cattle was estimated as 0.16 with no homozygous BB animal. Using the same set of primers as used in the Sahiwal cattle, a part of exon IV of buffalo CSN3 gene was amplified, but restriction enzyme analysis using HindIII/HinfI and TaqI did not reveal any polymorphism. However, DNA sequencing of the amplified fragment (GenBank Acc. No. U96662) revealed one polymorphism at codon 135 (ThrACC ?IleATC) in buffalo; the frequencies of 135 Thr/Ile alleles were estimated as 0.88 and 0.12, respectively.

Optical, DSC and X-ray studies show that Cn H2n+1, O Cm H2m OH (n=16; m=4; n=18 and 20, m= 2 and 3; n = 22, m=3)/aqueous H3 PO4 systems exhibit mesophases in the order middle - viscous isotropic - ...

We have studied the electroconvective behaviour of MBBA, with initial homeotropic boundary conditions, employing a.c. fields acting transversely to the line of sight. Two major types of convective structure occur. They may be described as the distorted-homeotropic (V D ) and distorted-planar (H D ) states. The first bifurcation is to the V D state and takes place at a threshold voltage which varies parabolically with the electrode-separation. The second bifurcation corresponds to V D -H D transformation occurring close to turbulence. The H D structure, once nucleated, propagates in a highly organized and coherently winding manner so that an array of + 1 linear defects form at the axes of circulation. The growth speed of H D front is strongly voltage dependent. Field induced undulatory structures develop along the V-H interface below the threshold of electroconvection.

A new type of highly organized, large scale propagation of vortical flow has been observed in MBBA subject to a transverse electric field. This is a transient phenomenon associated with the transformation, occurring at elevated voltages, between electrically distorted homeotropic and planar states. The convective flows generate an array of linear defects which persist even after removal of the field.

The AIBD has become the most important broadcasting training centre in Asia. Its director, R Balakrishnan discusses here not only organisational problems and issues associated with broadcasting training, but also attitudes that should necessarily be adopted by managements of broadcasting stations towards training.

An investigation of stratification is reported for a universe with strong positive skewness. The choice of stratification variable, the method of constructing strata, the sample allocation, and the number of strata are considered. Comparisons are made among four types of allocation in combination with the corresponding optimum stratifications. For four simpler methods of stratification, equal allocation and allocation proportional to stratum aggregates are contrasted. Gains from stratification are examined for several estimation variables. Illustrations utilize data for the 1961 universe of United States nonfederal, general medical hospitals for short-term care. However, the findings apply to the stratification of other populations having similar distribution functions.

Differential growth in the use of oral anovulents is explored through construction of separate time series for Canadian women classified by religion, education, and nativity. The series suggest that native-born Roman Catholic women are as likely as native-born Protestant women to be using oral contraceptives by the terminal point of our series in 1967. The period of very rapid growth in the use of orals appears to have come to an end. Differential patterns of diffusion of oral contraception shown by the categories of women discussed, suggest sources of bias in the profile of an aggregate time series.

Training courses in broadcasting should dovetail theory and practice carefully so that broadcasters, at all stages of their careers, could be enabled to fulfil most effectively, efficiently, and economically the jobs for which their talents and interests are best suited.