Melting Enthalpy and Entropy of Freestanding Metallic Nanoparticles Based on Cohesive Energy and Average Coordination Number

2011 ◽  
Vol 115 (35) ◽  
pp. 17310-17313 ◽  
Author(s):  
Hamed Omid ◽  
Hamid Delavari H. ◽  
Hamid R. Madaah Hosseini
Keyword(s):  
Coordination Number ◽  
Cohesive Energy ◽  
Metallic Nanoparticles ◽  
Melting Enthalpy ◽  
Average Coordination Number ◽  
Enthalpy And Entropy

Theoretical prediction of physical parameters of GexSb20−x Te80 (x = 11, 13, 15, 17, 19) bulk glassy alloys

2014 ◽  
Vol 32 (4) ◽  
pp. 661-668 ◽  
Author(s):  
Ishu Sharma ◽  
Monisha Maheshwari
Keyword(s):  
Coordination Number ◽  
Bond Energy ◽  
Cohesive Energy ◽  
Lone Pair ◽  
Average Coordination Number ◽  
Physical Parameters ◽  
Calculated Density ◽  
Glassy Alloys ◽  
Mean Bond Energy ◽  
Lone Pair Electrons

AbstractPhysical properties of GexSb20−x Te80 (x = 11, 13, 15, 17, 19) bulk glassy alloys are examined theoretically. Lone pair electrons are calculated using an average coordination number (〈r〉) and the number of valence electrons, and are found to decrease with an addition of Ge. Mean bond energy (〈E〉) is proportional to glass transition temperature (Tg) and shows maxima near the chemical threshold. Cohesive energy of the system is calculated using chemical bond approach. A linear relation is found between cohesive energy, band gap (calculated theoretically and confirmed experimentally) and average heat of atomization. All these parameters are increasing with an increase in Ge content. A relation between average single bond energy and photon energy is discussed. Compactness of the structure is measured from the calculated density of the glass. An attempt is made to discuss the results in terms of structure of the glass or equivalently with average coordination number.

Modeling the cohesive energy and melting point of nanoparticles by their average coordination number

2008 ◽  
Vol 145 (9-10) ◽  
pp. 432-437 ◽  
Author(s):  
M. Attarian Shandiz ◽  
A. Safaei ◽  
S. Sanjabi ◽  
Z.H. Barber
Keyword(s):  
Melting Point ◽  
Coordination Number ◽  
Cohesive Energy ◽  
Average Coordination Number

A Study of the Physical Properties of Te15(Se100-xBix)85 Glassy Alloys

2010 ◽  
Vol 305-306 ◽  
pp. 61-69 ◽  
Author(s):  
Kameshwar Kumar ◽  
Nagesh Thakur ◽  
S.C. Katyal ◽  
Pankaj Sharma
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Coordination Number ◽  
Bond Energy ◽  
Cohesive Energy ◽  
Energy Gap ◽  
Average Coordination Number ◽  
Glassy Alloys ◽  
Mean Bond Energy

In the present communication, a study was made of the compositional variation of physical properties: average coordination number (<r>), average number of constraints (Ncon), number of lone-pair electrons (L), mean bond energy (<E>), cohesive energy (CE), average heat of atomization (Hs), glass transition temperature (Tg), density (ρ) and theoretical energy gap (Eg) for Te15(Se100-xBix)85 (x = 0, 1, 2, 3, 4, 5at%) glassy alloys. The mean bond energy and the cohesive energy have been calculated using the chemical bond approach (CBA). The glass transition temperature was calculated using the Tichy-Ticha approach, and has been found to increase with Bi content. The mean bond energy is found to be proportional to the glass transition temperature and the average coordination number. It has been found that the average coordination number, average number of constraints, mean bond energy and density increase, whereas the cohesive energy, average heat of atomization and theoretical energy gap decrease with increasing Bi content in Se-Te alloys.

A Study on Microstructural Parameters for the Characterization of Granular Porous Ceramics Using a Combination of Stochastic and Mechanical Modeling

2017 ◽  
Vol 09 (05) ◽  
pp. 1750069 ◽  
Author(s):  
Matthias Kulosa ◽  
Matthias Neumann ◽  
Martin Boeff ◽  
Gerd Gaiselmann ◽  
Volker Schmidt ◽  
...  
Keyword(s):  
Coordination Number ◽  
Elastic Properties ◽  
Three Dimensional ◽  
Porous Ceramics ◽  
Average Coordination Number ◽  
Mechanical Modeling ◽  
Element Analysis ◽  
Coordination Numbers ◽  
Microstructural Parameters ◽  
Microstructure Model

To correlate the mechanical properties of granular porous materials with their microstructure, typically porosity is being considered as the dominant parameter. In this work, we suggest the average coordination number, i.e., the average number of connections that each grain of the porous material has to its neighboring grains, as additional — and possibly even more fundamental — microstructural parameter. In this work, a combination of stochastic and mechanical modeling is applied to study microstructural influences on the elastic properties of porous ceramics. This is accomplished by generating quasi-two-dimensional (2D) and fully three-dimensional (3D) representative volume elements (RVEs) with tailored microstructural features by a parametric stochastic microstructure model. In the next step, the elastic properties of the RVEs are characterized by finite element analysis. The results reveal that the average coordination number exhibits a very strong correlation with the Young’s modulus of the material in both 2D and 3D RVEs. Moreover, it is seen that quasi-2D RVEs with the same average coordination number, but largely different porosities, only differ very slightly in their elastic properties such that the correlation is almost unique. This finding is substantiated and discussed in terms of the load distribution in microstructures with different porosities and average coordination numbers.

Size-dependent melting temperature of nanoparticles based on cohesive energy

2014 ◽  
Vol 28 (19) ◽  
pp. 1450157 ◽  
Author(s):  
Kai-Tuo Huo ◽  
Xiao-Ming Chen
Keyword(s):  
Melting Temperature ◽  
Cohesive Energy ◽  
Metallic Nanoparticles ◽  
Present Model ◽  
Packing Fraction ◽  
Size Dependent ◽  
Crystal Cell ◽  
K Factor ◽  
The Relationship ◽  
Crystalline Plane

Size-dependent melting temperature of metallic nanoparticles is studied theoretically based on cohesive energy. Three factors are introduced in the present model. The k factor, i.e. efficiency of space filling of crystal lattice is defined as the ratio between the volume of the atoms in a crystal cell and that of the crystal cell. The β factor is defined as the ratio between the cohesive energy of surface atom and interior atom of a crystal. The qs factor represents the packing fraction on a surface crystalline plane. Considering the β, qs and k factors, the relationship between melting temperature and nanoparticle size is discussed. The obtained model is compared with the reported experimental data and the other models.

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