Polyschiff bases—I.: Syntheses and properties of polyschiff bases from 5,5′-thiobisfurfural

PolySchiff bases have been synthesized from 5,5′-thiobisfurfural and various diamines such as o-, m- and p-phenylenediamines, benzidine, 3,3′-dimethoxybenzidine, 3,3′-dimethylbenzidine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylsulphone and aliphatic diamines such as ethylenediamine and hexamethylenediamine under various experimental conditions. The polymers have been characterized by i.r. spectral and thermal studies and by measurement of electrical conductivity at various temperatures.     

On Wait-and-See Stochastic Linear Programmes: An Application and an Algorithm

This paper develops a computational algorithm for estimating the mean objective function value of a stochastic linear programming problem of the passive or wait-and-see type. The algorithm is applied to a problem connected with design of a milk-grid in India and is found to be computationally effective in that case. It is most likely to be useful in the case of fairly large LP problems with a few (<10) stochastic right hand side variables.     

Vibrational spectra and normal coordinate analysis of dihalogenated benzenes. II. Out-of-plane vibrations

Assignments of the out-of-plane fundamental modes for D₄-ortho, meta and para fluorochloro and fluorobromo benzenes are given. A normal coordinate analysis, employing the 94 observed frequencies of the H₄ and D₄ molecules is carried out to obtain a 16-parameter Valence Force Feld, with an average difference of ±1.2% between observed and calculated frequencies. Unique assignments are obtained in the spectra of D₄-compounds for several of the weak or overlapping bands assigned as fundamentals in the H₄-compounds.     

Optical coupling of two injection lasers: A new experimental approach to study the gain broadening mechanism

A new type of experiment, the optical coupling of two injection lasers, is presented. This method is used to study the gain broadening mechanism for three different types of laser structures: proton bombarded stripe geometry,V-groove, and channeled substrate planar stripe (CSP) lasers. The gain reduction in the presence of a strong injected light is detected with high sensitivity by a differential measurement. Independent of the laser structure, the homogeneous gain broadening mechanism is by far dominating.     

Chemistry of geminal-dithiolates derived from cyano-substituted tetrathiafulvalenes

Tetracyanotetrathiafulvalene reacts with two equivalents of thiol salts (RS^?) to give 1,2-dicyano-1,2-di RS ethene and a geminal dithiolate intermediate which reacts with a variety of reagents to provide novel tetrathioethene derivatives, such as reaction with 3-chloro-2-butanone and acid to give dimethyldicyanotetrathiafulvalene.     

Composition and in vitro cytotoxic activities of essential oil of Hedychium spicatum from different geographical regions of western Himalaya by principal components analysis

The rhizome of Hedychium spicatum has been widely used in traditional medicines. The present study deals with the evaluation of the cytotoxic potential of rhizome essential oils from four different regions of the Western Himalaya (India) along with comparative correlation analysis to characterise the bioactive cytotoxic component. The essential oils were coded as MHS-1, MHS-2, MHS-3 and MHS-4, and characterised using GC-FID and GC–MS. The main volatile compounds identified were 1,8-cineol, eudesmol, cubenol, spathulenol and α-cadinol. In vitro cytotoxic activities were assessed against human cancer cell lines such as, the lung (A549), colon (DLD-1, SW 620), breast (MCF-7, MDA-MB-231), head and neck (FaDu), and cervix (HeLa). MHS-4 is significantly active in comparison to other samples against all cancer cell lines. Sample MHS-4 has major proportion of monoterpene alcohol mainly 1,8-cineol. Principal components analysis was performed for the experimental results and all four samples were clustered according to their percentage inhibition at different doses.     

Enhanced electrocaloric effect in Ba0.85Ca0.15Zr0.1Ti0.9–xSnxO3 ferroelectric ceramics

The present work deals with the study of effect of Sn addition (0%–6% by mole) on the electrocaloric (EC) performance of Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃ (BCZT) ceramics. Maxwell's relations in conjunction with data from experimental observations were used for the indirect caloric measurements. Small percentage change with Sn addition is found to increase the EC performance of BCZT ceramics. A peak adiabatic temperature change of 0.84 K (353 K) was predicted for 0–32 kV/cm electric field, significantly higher than pristine BCZT ceramics. A simultaneous increase in specific entropy change was also observed.     

Thermodynamic and structural properties of methanol-water solutions using nonadditive interaction models

We study bulk structural and thermodynamic properties of methanol-water solutions via molecular dynamics simulations using novel interaction potentials based on the charge equilibration (fluctuating charge) formalism to explicitly account for molecular polarization at the atomic level. The study uses the TIP4P-FQ potential for water-water interactions, and the CHARMM-based (Chemistry at HARvard Molecular Mechanics) fluctuating charge potential for methanol-methanol and methanol-water interactions. In terms of bulk solution properties, we discuss liquid densities, enthalpies of mixing, dielectric constants, self-diffusion constants, as well as structural properties related to local hydrogen bonding structure as manifested in radial distribution functions and cluster analysis. We further explore the electronic response of water and methanol in the differing local environments established by the interaction of each species predominantly with molecules of the other species. The current force field for the alcohol-water interaction performs reasonably well for most properties, with the greatest deviation from experiment observed for the excess mixing enthalpies, which are predicted to be too favorable. This is qualitatively consistent with the overestimation of the methanol-water gas-phase interaction energy for the lowest-energy conformer (methanol as proton donor). Hydration free energies for methanol in TIP4P-FQ water are predicted to be -5.6 +/- 0.2 kcal/mol, in respectable agreement with the experimental value of -5.1 kcal/mol. With respect to solution microstructure, the present cluster analysis suggests that the microscale environment for concentrations where select thermodynamic quantities reach extremal values is described by a bipercolating network structure.