The effect of temperature and salinity on the Setschenow parameters of naphthalene in seawater

1989 ◽  
Vol 67 (5) ◽  
pp. 822-826 ◽  
Author(s):  
Gerardo Gold ◽  
Silvio Rodriguez
Keyword(s):  
Surface Tension ◽  
Free Energy ◽  
Temperature Dependence ◽  
Effect Of Temperature ◽  
Salting Out ◽  
Column Method ◽  
Generator Column ◽  
Enthalpy And Entropy ◽  
Experimental Values ◽  
Nonpolar Molecules

Solubility measurements of naphthalene in seawater of different salinities have been determined by the Generator Column Method in the 276.6 K to 316.8 K temperature range. The Gibbs free energy, enthalpy, and entropy of solution were evaluated at 298 K by means of the Clarke and Glew equation. The temperature dependence of the Setschenow parameters for naphthalene in seawater has been studied and compared with the values calculated using current models for the salting-out of nonpolar molecules. The Surface Tension Approach gives the best correlation with experimental values. Keywords: Setschenow parameters, solubility of naphthalene in seawater.

Intermolecular Study of Adansonia Digitata (AnD) Binary Liquid Mixture

2014 ◽  
Vol 348 ◽  
pp. 226-231
Author(s):  
Sushil Phadke ◽  
Suneel Kumar Ujle ◽  
Bhaktdarshan Shrivastava ◽  
Ashutosh Mishra ◽  
Nagesh Dagaonkar
Keyword(s):  
Surface Tension ◽  
Free Energy ◽  
Atp Hydrolysis ◽  
Intermolecular Forces ◽  
Direct Measure ◽  
Adansonia Digitata ◽  
A Cell ◽  
Dynamic Quantity ◽  
Enthalpy And Entropy ◽  
The Universe

The resistance of a liquid to flow and the molecules of a liquid exhibit intermolecular attraction for each another and are called its viscosity and surface tension. Surface tension is measured as the energy required to increase the surface area of a liquid by a unit of area. Viscosity is governed by the strength of intermolecular forces and especially by the shapes of the molecules of a liquid. The surface tension of a liquid results from an imbalance of intermolecular attractive forces, the cohesive forces between molecules. The change in free energy during a reaction, it is a direct measure of the amount disorder that is created in the universe when the reaction occurs. A thermo-dynamic quantity combining enthalpy and entropy into a single value is called the Gibbs free energy ΔG. The value of ΔG for a reaction is a direct measure of how far the reaction is from equilibrium. The large negative value for ATP hydrolysis in a cell merely reflects the fact that cells keep the ATP hydrolysis reaction as much as 10 orders of magnitude away from the equilibrium. The change of free energy is equal to the sum of its enthalpy plus the product of the temperature and entropy of the system. The characteristic time for a system to reach an equilibrium condition after a disturbance is called relaxation time.Adansonia Digitata(AnD) fruit collected from Mandav District Dhar (M.P.). The entire chemical used in this study analytical grade.

Surface tension and heat of the surface formation of liquids

2020 ◽  
Vol 34 (31) ◽  
pp. 2050300
Author(s):  
E. A. Eyvazov ◽  
A. B. Ibrahimli
Keyword(s):  
Surface Tension ◽  
Critical Temperature ◽  
Specific Heat ◽  
Temperature Dependence ◽  
Satisfactory Agreement ◽  
Research Work ◽  
Potential Method ◽  
Surface Tension Coefficient ◽  
Surface Formation ◽  
Experimental Values

By the potential method, it was determined that regardless of the nature of the liquid, the surface tension coefficient is determined by [Formula: see text]. In this expression, [Formula: see text] is the specific heat of the surface formation, [Formula: see text] is the critical temperature. According to our approach, the specific heat of the surface formation (SHS) also depends on temperature: [Formula: see text] ([Formula: see text] — the specific heat of the surface formation at the mealting temperature, [Formula: see text] — thermal coefficent of SHS). In this research work, the temperature dependence of the surface tension coefficient was calculated for seven dissimilar liquids. It was revealed that the calculated values of [Formula: see text] are in satisfactory agreement with the available experimental values.

On the surface tension and shear viscosity of square-well fluids

1981 ◽  
Vol 59 (5) ◽  
pp. 673-677
Author(s):  
S. K. Datta
Keyword(s):  
Surface Tension ◽  
Shear Viscosity ◽  
Spherical Model ◽  
Viscosity Coefficient ◽  
Model Approximation ◽  
Mean Spherical Model ◽  
Square Well ◽  
Experimental Values ◽  
Real Fluids ◽  
Nonpolar Molecules

Closed analytical expressions for the surface tension and the shear viscosity coefficient of a square-well fluid have been obtained using the mean spherical model approximation (MSMA) and the exact hard sphere equation of state given by Carnahan and Stirling. The expressions are then used to calculate these properties for some real fluids. The fair agreement between the calculated and experimental values in the case of several symmetric nonpolar molecules, suggests that the representation of the attractive tail by a square-well potential is a satisfactory one even in the calculation of these complex properties and that the use of MSMA in the elucidation of the equilibrium and transport properties of liquids provides a more or less satisfactory and convenient approach.

scholarly journals Effect of temperature on mixing behavior and stability of liquid Al-Fe alloys

2021 ◽  
Vol 2070 (1) ◽  
pp. 012025
Author(s):  
I B Bhandari ◽  
N Panthi ◽  
S Gaire ◽  
Ishwar Koirala
Keyword(s):  
Free Energy ◽  
Surface Composition ◽  
Dynamic Properties ◽  
Enthalpy Of Mixing ◽  
Effect Of Temperature ◽  
Mixing Enthalpy ◽  
Energy Parameters ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing ◽  
Experimental Values

Abstract A theoretical model based on the assumption of compound formation in binary liquid alloy has been used to investigate the thermodynamic properties (free energy of mixing, enthalpy of mixing and entropy of mixing), microscopic properties (concentration fluctuation in long wavelength limit and chemical short range order parameter), surface properties (surface tension and surface composition) and dynamic properties ( viscosity and diffusion coefficient). All the properties of Al2Fe binary melt have been measured using the same energy parameters configured for experimental values of free energy of mixing. The energy parameters are detected as independent of concentration, but depend on temperature. The findings are well consistent with the experimental standards.

Solubility measurements and determination of Setschenow constants for the pesticide carbaryl in seawater and other electrolyte solutions

1992 ◽  
Vol 70 (12) ◽  
pp. 2864-2868 ◽  
Author(s):  
Miguel Angel Huerta-Diaz ◽  
Silvio Rodriguez
Keyword(s):  
Salt Effect ◽  
Electrolyte Solutions ◽  
Artificial Seawater ◽  
Salting Out ◽  
Column Method ◽  
Generator Column ◽  
Carbamate Pesticide

Accurate solubility measurements covering the range 278–318 K were obtained for the carbamate pesticide carbaryl (1-naphthyl-N-methylcarbamate) in water, natural and artificial seawater, and NaCl, Na2SO4, CaCl2, and (CH3)4NBr electrolyte solutions. Carbaryl solubilities were determined using a combination of a generator column method and spectrophotometric techniques. In all cases the solubility of carbaryl in water and in the electrolyte solutions increased with an increase in temperature. The salt effect on the pesticide solubility as a function of temperature was obtained by calculating the Setschenow constants for each one of the electrolyte solutions. Salting-out was observed in solutions prepared with NaCl, Na2SO4, and CaCl2 as well as in natural and artificial seawater, whereas salting-in was observed with (CH3)4NBr solutions.

Strength Hierarchy for Nano-Sized Crystals

2013 ◽  
Vol 592-593 ◽  
pp. 301-306 ◽  
Author(s):  
Sergiy Kotrechko ◽  
Igor Mikhailovskij ◽  
Tatiana Mazilova ◽  
Oleksandr Ovsjannikov
Keyword(s):  
Surface Tension ◽  
Temperature Dependence ◽  
Three Dimension ◽  
Local Instability ◽  
Local Stresses ◽  
The World ◽  
Main Factors ◽  
Experimental Values ◽  
Thermal Vibrations ◽  
Monatomic Chain

A concept of atomic mechanisms governing strength of nanosized defect-free crystals is presented. It is exhibited that these mechanisms consist in local instability of the lattice. Two main reasons for localization of instability in three-dimension (3D) crystals are analyzed, namely, (i) fluctuation of local stresses induced by thermal vibrations of atoms, and (ii) non-uniform distribution of local stresses caused by a surface tension. Based on this conception, explanations of both the temperature dependence of strength of 3D nanocrystals and scale effect are given. Ideas on the reasons for and regularities of change in strength at transition from 3D to 2D (graphene) and 1D (monatomic chain) crystals are represented. It is shown that dimensionality of crystal is one of the main factors governing strength of defect-free crystals. Experimental values of the strength of carbon monatomic chains are given, which times exceeds the strength of graphene and is the highest attainable level of strength in the world.

Automated Assessment of Binding Affinity via Alchemical Free Energy Calculations

2020 ◽  
Author(s):  
Maximilian Kuhn ◽  
Stuart Firth-Clark ◽  
Paolo Tosco ◽  
Antonia S. J. S. Mey ◽  
Mark Mackey ◽  
...  
Keyword(s):  
Free Energy ◽  
Protein Structures ◽  
Free Energy Calculations ◽  
Distinct Advantage ◽  
Binding Affinities ◽  
Structure Based Drug Design ◽  
Energy Calculations ◽  
Kendall’S Τ ◽  
Experimental Values ◽  
Better Than

Free energy calculations have seen increased usage in structure-based drug design. Despite the rising interest, automation of the complex calculations and subsequent analysis of their results are still hampered by the restricted choice of available tools. In this work, an application for automated setup and processing of free energy calculations is presented. Several sanity checks for assessing the reliability of the calculations were implemented, constituting a distinct advantage over existing open-source tools. The underlying workflow is built on top of the software Sire, SOMD, BioSimSpace and OpenMM and uses the AMBER14SB and GAFF2.1 force fields. It was validated on two datasets originally composed by Schrödinger, consisting of 14 protein structures and 220 ligands. Predicted binding affinities were in good agreement with experimental values. For the larger dataset the average correlation coefficient Rp was 0.70 ± 0.05 and average Kendall’s τ was 0.53 ± 0.05 which is broadly comparable to or better than previously reported results using other methods. <br>

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