the intermolecular forces between water molecules are of great importance in many areas of chemistry including solvation, solution chemistry, and biochemistry. as a result of this (h2o)n systems have received a great significant of attention, both experimental and theoretical. all calculation of this study are carried out by gaussian 98 soft ware. geometry optimization for each cluster were be ...

using gaussian 03, software the thermodynamic functions such as gibbs free energy, g, enthalpy, h, and entropy, s, of alanine and valine amino acids were theoretically studied at different solvents. first, the density functional theory (b3lyp) level with 3-21g, 6-31g and 6-31+g basis sets were employed to optimization of isolated alanine and valine amino acids in the gas phase. moreover, vib...

A thermodynamic analysis of an operational 315 MW supercritical steam power plant (SPP) using the actual data is performed to assess the plant performance and identify the sites of energy losses and exergy destructions in each component of the plant. Various performance parameters such as component energy and exergy efficiencies, energy loss rate, exergy destruction rate, improvement potential ...

We determine the relative thermodynamic stability of competing homogeneously and inhomogeneously ordered ferroelectric phases of PbTiO3 using its free-energy landscape, obtained from constrained-polarization moleculardynamics simulations with a first-principles effective Hamiltonian and thermodynamic integration. While we find that the tetragonal structure is thermodynamically most stable at te...

The aim of thermodynamic integration is to compute the difference in a thermodynamic property (usually the free energy) of the system between some reference state and the state of interest. To measure the free energy change from initial to final state, thermodynamic parameters characterizing the system are changed infinitely slowly so that at each stage along the path the system is in equilibri...

application of cogeneration systems based gas turbine for heat and power production is increasing. because of finite natural energy resources and increasing energy demand the cost effective design of energy systems is essential. cgam problem as a cogeneration system is considered here for analyzing. two new approaches are considered, first in thermodynamic model of gas turbine and cogeneration ...

The removal of dyes from wastewater, is one of the major environmental concerns due to their high color density, and they are toxic at even low concentrations. Adsorption process by advanced oxidation processes (AOPs) has been found to be a more effective method than classical methods for treating dye-containing wastewater. This research, is to investigate the decolorization abilities of az...