scholarly journals Determination of bulk and surface properties of liquid Bi-Sn alloys using an improved quasi-lattice theory

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Olugbenga Morayo Oshakuade ◽  
Oluseyi Ezekiel Awe
Keyword(s):  
Lattice Theory ◽  
Binary Systems ◽  
Composition Range ◽  
Enthalpy Of Mixing ◽  
Free Energies ◽  
Surface Enrichment ◽  
Coordination Numbers ◽  
Nearest Neighbours ◽  
Fitting Parameters

Abstract The thermodynamic properties of Bi-Sn were studied at 600 and 900 K using a quasi-lattice theory. After successful fitting of Gibbs free energies of mixing and thermodynamic activities, the fitting parameters were used to investigate the enthalpy of mixing, the entropy of mixing, concentration fluctuations, Warren-Cowley short-range-order parameter, surface concentrations and surface tensions of the binary systems. Positive and symmetrically shaped enthalpies of mixing were observed in all composition range, while negative excess entropies of mixing were observed. Bi-Sn showed a slight preference for like-atoms as nearest neighbours in all composition range. The nature of atomic order in Bi-Sn at 600 and 900 K appeared similar. The highest tendency for homocoordination exists at composition where mole fraction of Bi is about 40%. It was also observed that Bi (whose surface tension is lower than that of Sn) has the highest surface enrichment in the Bi-Sn systems. Unlike many previous applications of the quasi-lattice theory where constant values were used to approximate coordination numbers, temperature and composition-dependent coordination numbers were applied in this work.

Calorimetric Investigation of MCI-EuCI2 Melts (M = Na, K, Rb)

2001 ◽  
Vol 56 (9-10) ◽  
pp. 653-657
Author(s):  
F. Da Silva ◽  
L. Rycerz ◽  
M. Gaune-Escard
Keyword(s):  
Least Squares ◽  
Interaction Parameter ◽  
Atmospheric Pressure ◽  
Binary Systems ◽  
Composition Range ◽  
Enthalpy Of Mixing ◽  
Mixing Enthalpy ◽  
Calorimetric Investigation ◽  
Direct Calorimetry ◽  
Enthalpies Of Mixing

Abstract The molar enthalpies of mixing (ΔmixHm) of MCl-EuCl2 (M = Na, K, Rb) liquid binary systems were measured at 1138 K over the whole composition range by direct calorimetry. A Calvet type calorimeter was used, and mixing of the two liquid components was achieved by the ampoule break-off technique under argon at atmospheric pressure. The enthalpy of mixing of these systems is negative over the whole composition range with a minimum of approximately -0.5, -3.5 and -4.5 kJ mol-1 for M = Na, K, Rb, respectively. The least-squares coefficients A, B, C in the equation A (kJ mol-1) = A + B x + C x2, where λ is an interaction parameter, are reported. From the trend observed in these MCl-EuCl2 systems it was possible to estimate the mixing enthalpy of the CsCl-EuCl2 system.

Using Thermodynamics to Assess the Molecular Interactions of Tetrabutylphosphonium Carboxylate–Water Mixtures

2019 ◽  
Vol 72 (2) ◽  
pp. 144 ◽  
Author(s):  
Darius J. Yeadon ◽  
Johan Jacquemin ◽  
Natalia V. Plechkova ◽  
Margarida Costa Gomes ◽  
Kenneth R. Seddon
Keyword(s):  
Experimental Data ◽  
Hydrogen Bonding ◽  
Atmospheric Pressure ◽  
Binary Systems ◽  
Composition Range ◽  
Partial Molar Volumes ◽  
Negative Deviation ◽  
Free Energies ◽  
Hydrogen Bonding Interactions ◽  
Water Values

Densities, ρ, viscosities, η, and enthalpies of mixing, , of binary [P4 4 4 4][CnCOO]–water mixtures (with n=1, 2 or 7) were determined at atmospheric pressure as a function of temperature. The excess, , apparent, , and partial, , molar volumes were deduced from experimental data, as well as fragilities, m*, and excess Gibbs free energies of activation of viscous flow, . exhibited predominantly negative deviation from ideality, with a minimum at approximately ~0.8 for all three systems, indicating strong hydrogen-bonding interactions. All three binary systems were found to be fragile, with [P4 4 4 4][C7COO] showing the smallest deviations in fragility with the addition of water. values of the systems were exothermic over the entire composition range, having the following trend: [P4 4 4 4][C2COO]>[P4 4 4 4][C7COO]>[P4 4 4 4][C1COO].

DETERMINATION OF THE ACTIVITIES OF MAGNESIUM IN LIQUID MAGNESIUM–TIN ALLOYS BY VAPOR PRESSURE MEASUREMENTS

1962 ◽  
Vol 40 (4) ◽  
pp. 718-728 ◽  
Author(s):  
S. Ashtakala ◽  
L. M. Pidgeon
Keyword(s):  
Vapor Pressure ◽  
Liquid Alloy ◽  
Composition Range ◽  
Entire Composition Range ◽  
Pressure Measurements ◽  
Free Energies ◽  
Tin Alloys ◽  
Vapor Pressure Measurements

The vapor pressure of liquid magnesium–tin alloys has been measured between 780 °C and 1010 °C using the isopiestic method.Activities of magnesium were obtained at 800 °C, 910 °C, and 940 °C. Activities of tin showed a negative departure from ideality, and those of magnesium, both negative and a slight positive departure.Partial heats and entropies of mixing were calculated, and values are negative for most of the composition range. Partial free energies of mixing for the entire composition range showed negative values. Integral heats, entropies, and free energies were calculated from the partial quantities. These values were negative, indicating an ordered liquid alloy.

Röntgenbeugungsuntersuchung an geschmolzenem Selen und Tellur sowie an Legierungen des Systems Selen—Tellur/ X-ray Diffraction Study of Molten Selenium, and Tellurium and of Molten Selenium — Tellurium-Alloys

1975 ◽  
Vol 30 (12) ◽  
pp. 1633-1639 ◽  
Author(s):  
W. Hoyer ◽  
E. Thomas ◽  
M. Wobst
Keyword(s):  
Chain Length ◽  
Short Range ◽  
Short Range Order ◽  
Coordination Shell ◽  
Range Order ◽  
Average Chain Length ◽  
X Ray Diffraction ◽  
Coordination Numbers ◽  
Nearest Neighbours ◽  
Increasing Temperature

Abstract At temperatures just above the melting point molten Selenium seems to be a mixture of long chains and eight-membered rings. With increasing temperature the number of rings and the average chain length decrease. At 460 °C the average chain length lies in the range of 10 atoms.In a slightly supercooled Tellurium-melt the number of first neighbours is two. The atoms are arranged in chains. Selenium rich Se-Te-alloy-melts are built up of mixed chains. It seems to be possible, that a smaller part of atoms forms Se6Te2 rings. At Tellurium concentrations higher than approximately 50 at.-% the chainlike structure with two next nearest neighbours changes to a disturbed Arsen-like short range order. The number of electrons in the first coordination shell, the short range order parameter introduced by Cowley and the partial coordination numbers show that Se-Te-alloys are of the "solution system" type, but in the whole concentration range for each atom there is a tendency to have "strange coordination".

scholarly journals Computational Determination of Binding Structures and Free Energies of Phosphodiesterase-2 with Benzo[1,4]diazepin-2-one Derivatives

2010 ◽  
Vol 114 (48) ◽  
pp. 16020-16028 ◽  
Author(s):  
Bo Yang ◽  
Adel Hamza ◽  
Guangju Chen ◽  
Yan Wang ◽  
Chang-Guo Zhan
Keyword(s):  
Free Energies
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