Studies on Water-Polymer Interactions inthe Presence of Aceclofenac at 298.15 K

Densities and ultrasonic velocities of aqueous mixtures of methyl cellulose (MC) and polyethylene glycol (PEG) and of methyl cellulose and hydroxyl propyl methyl cellulose (HPMC), over the compositions, 9:1, 8:2 and 6:4, and of MC, HPMC and PEG, over the compositions, 9:0.5:0.5, 8:1:1 and 6:2:2, have been measured with and without acelofenac at 298.15K and at atmospheric pressure. The experimental ultrasonic velocities have been used to determine isentropic compressibilities, apparent isentropic molar compressibilities, acoustic impedance, molar compressibility, molar sound velocity, free volume and relative association for the systems with and without aceclofenac. The results have been discussed in terms of solute solvent and solute-solute interactions and various structural effects

Surface magneto-optics in yttrium iron garnets

We report a study of surface reconstruction effects in yttrium iron garnets using density functional theory. This work responds to the need to explain the physical basis of recent experimental results showing a significant enhancement in Faraday rotation in iron garnets. These materials are extensively used in the telecom industry for nonreciprocal device applications. Understanding the physical basis of the heightened Faraday response at the surface is important for the development of ultrathin nonreciprocal devices. Our results show that the bandgap near the surface is significantly reduced compared to that of the bulk, and that spin-orbit coupling effects become more important near the surface. We find that the decrease in band gap results in an enhancement and change in direction in the Faraday rotation in the visible range all the way to the deep red. Electronic transition matrix elements for surface-sensitive ultra-thin layers are calculated and compared to those of bulk samples, leading to the conclusion that the octahedrally-oxygen-coordinated iron sublattice in these ferrimagnetic materials is more strongly affected by surface reconstruction than the other, anti-ferromagnetically coupled, tetrahedral sublattice. We explain how these changes contribute to the enhancement in magneto-optic response near the surface as compared to the bulk

Studies on the Solute Solvent Interaction of Nimesulide in Aqueous Solutions of Hydrotropic Agents at Different Temperatures

The present study deals with experiments so as to highlight the solute (drug nimesulide) - solvent(water) interactions and related modifications in case of the presence of hydrotropic agents at different temperatures T(=298.15 to 313.15)K. Density and viscosity values of nimesulide have been determined in water in (0.1, 0.2, 0.4, 0.6, 0.8, 1 and 2) mol dm-3 aqueous solutions of hydrotropic agents (sodium benzoate, sodium salicylate, sodium bromide and nicotinamide) at temperatures 298.15, 303.15, 308.15 and 313.15 K where as the solubility was studied at 308.15 K. From the density values, the limiting partial molar volumes and expansibilities have been calculated. The experimental viscosity values have been analyzed in terms of jones-dole equation and on the basis of transition theory for relative viscosity

Studies on Water-Polymer Interactions inthe Presence of Aceclofenac at 298.15 K

Densities and ultrasonic velocities of aqueous mixtures of methyl cellulose (MC) and polyethylene glycol (PEG) and of methyl cellulose and hydroxyl propyl methyl cellulose (HPMC), over the compositions, 9:1, 8:2 and 6:4, and of MC, HPMC and PEG, over the compositions, 9:0.5:0.5, 8:1:1 and 6:2:2, have been measured with and without acelofenac at 298.15K and at atmospheric pressure. The experimental ultrasonic velocities have been used to determine isentropic compressibilities, apparent isentropic molar compressibilities, acoustic impedance, molar compressibility, molar sound velocity, free volume and relative association for the systems with and without aceclofenac. The results have been discussed in terms of solute solvent and solute-solute interactions and various structural effects