This paper deals with thermodynamic optimization of supercritical CO2 recompression and partial cooling cycles operating at cycle maximum temperature 680°C pressure 250 bar. The primary goal to investigate the effects variation in heat sink (ambient air temperature), mass split fraction (X), minimum (Pmin) on thermal efficiency power cycles. Response surface method (RSM) is adopted create a sec...

Periodic density functional theory (DFT) has been used to study the coadsorption of hydrogen and benzene on Pd(111). The most stable coverages are predicted by constructing the thermodynamic phase diagram as a function of gas-phase temperature and pressure. The common approximation that neglects vibrational contributions to the surface Gibbs free energy, using the PW91 functional, is compared t...

Sulfonamides are drugs extensively used for the treatment of certain infections caused by gram-positive and gram-negative microorganisms, some fungi, and certain protozoa. Several physical and chemical parameters of these compounds have been correlated with their chemotherapeutic activity: pK a , protein binding, and electronic charge distribution, among others. Unfortunately, no single paramet...

The present study is concerned with the kinetics and thermodynamic study of urease extracted from soybeans. The effect of pH, temperature, concentration of substrate and incubation time on the urease activity was examined. Maximum urease activity (86.79 ± 2.43 U/g) was obtained at 30 o C and pH 8.0 after 60 sec of incubation. Kinetics constants i.e. Km and Vmax were estimated by using Lineweave...

The experimental determination of formation constant for interaction of two water soluble phthalocyanines, Cobalt (II) 4,4',4",4'"-tetrasulpho phthalocyanine (CoTsPc ) and Manganese(II) 4,4',4",4"-tetrasulpho phthalocyanine (MnTsPc ) , with calf thymus DNA have been studied by UV-Vis spectrophotometric method at lrnM phosphate buffer , pH 7.4 and at 5 different temperatures 20,25,30,35 and 400 ...

Changes in the (31)P NMR chemical shift of tri-n-butylphosphine oxide have been measured as function of solvent composition in a number of binary solvent mixtures. The data were analysed using a model that separates the contributions of specific H-bond interactions with the first solvation shell and the non-specific effects of the bulk solvent on the chemical shift. This allowed measurement of ...

Assemblies of trans-bis(N-methylpyridinium-4-yl)diphenylporphine ions on the surface of calf thymus DNA have been studied using several spectroscopic techniques: absorbance, circular dichroism, and resonance light scattering. The aggregation equilibrium can be treated as a two-state system-monomer and assembly-each bound to the nucleic acid template. The aggregate absorption spectrum in the Sor...

Much attention has recently been focused on a fascinating subclass of metal-organic frameworks that behave in a remarkable stimuli-responsive fashion. These soft porous crystals feature dynamic crystalline frameworks displaying reversible, large-amplitude structural deformations under external physical constraints such as temperature, electric field or gas exposure. The number of reported synth...

[1] The vibrational properties of Mg2SiO4 wadsleyite have been calculated over a wide pressure range using density functional perturbation theory (DFPT). Both the normal mode frequencies and their volume dependences are consistent with the available Raman and infrared data. We provide detailed information about vibrational properties that are still not experimentally available. The vibrational ...

Reverse micellar systems are nanofluids with unique properties that make them attractive in high selectivity separation processes, especially for biological compounds. Understanding the phase behavior and thermodynamic properties of these nanosystems is the first step in process design. Separation of components by these nanosystems is performed upon contact of aqueous and reverse micellar phase...