Diameter-dependent thermodynamic and elastic properties of metallic nanoparticles

2015 ◽  
Vol 29 (08) ◽  
pp. 1550025 ◽  
Author(s):  
Jeewan Chandra ◽  
Kuldeep Kholiya
Keyword(s):  
Elastic Properties ◽  
Metallic Nanoparticles ◽  
Close Agreement ◽  
Present Formulation ◽  
Evaporation Temperature ◽  
Theoretical Approaches ◽  
Simple Theoretical Model ◽  
Experimental Findings ◽  
Temperature Melting ◽  
Melting Entropy

A simple theoretical model has been proposed to study the diameter-dependent properties of metallic nanoparticles, i.e. Ag , Au , Al , Ni , Pb , Cu and Fe . The diameter-dependent thermodynamic properties includes melting temperature, Debye temperature, evaporation temperature, melting enthapy and melting entropy. The model is also extended to study the diameter-dependent elastic properties including bulk modulus, Young's modulus and thermal expansion coefficient. On comparison with available experimental findings and other theoretical approaches, the results obtained with the present formulation depict a close agreement and demonstrate the validity of the method proposed in the present paper.

Modeling the melting temperature, melting entropy and melting enthalpy of freestanding metallic nanoparticles

2020 ◽  
Vol 241 ◽  
pp. 122280 ◽  
Author(s):  
Xiao Bao Jiang ◽  
Bei Bei Xiao ◽  
Rui Lan ◽  
Xiao Yan Gu ◽  
Hong Chao Sheng ◽  
...  
Keyword(s):  
Melting Temperature ◽  
Metallic Nanoparticles ◽  
Melting Enthalpy ◽  
Temperature Melting ◽  
Melting Entropy

scholarly journals Effect of Shape and Size on Curie Temperature, Debye Frequency, Melting Entropy and Enthalpy of Nanosolids

2018 ◽  
Vol 34 (5) ◽  
pp. 2282-2291
Author(s):  
Madan Singh ◽  
Benedict Molibeli Taele ◽  
Ghanshyam Patel
Keyword(s):  
Curie Temperature ◽  
Metallic Nanoparticles ◽  
Theory Model ◽  
Model Free ◽  
Bond Theory ◽  
Melting Thermodynamics ◽  
Debye Frequency ◽  
Shape And Size ◽  
Temperature Melting ◽  
Melting Entropy

The shape and size dependent melting thermodynamics of metallic nanoparticles are predicted by application of bond theory model, free of any adjustable parameter. Thermodynamic properties like Debye frequency, Curie temperature, melting entropy and enthalpy of Al, Sn, In, Cu, β-Fe and Fe3O4 for spherical and non spherical shapes nanoparticles with different size have been studied. In this model, the effects of relaxation factor for the low dimension solids are considered. The depression in Debye frequency, Curie temperature, melting entropy and enthalpy is predicted. The model predictions are supported by the available experimental and simulation results.

scholarly journals Modeling for the study of thermophysical properties of metallic nanoparticles

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Ratan Lal Jaiswal ◽  
Brijesh Kumar Pandey
Keyword(s):  
Thermodynamic Properties ◽  
Specific Heat ◽  
Thermophysical Properties ◽  
Cohesive Energy ◽  
Metallic Nanoparticles ◽  
Shape Effect ◽  
Great Effort ◽  
Dangling Bond ◽  
Experimental Findings ◽  
Melting Entropy

AbstractSuccessful description and explanation of thermophysical properties at the nano level is a task of great challenge even yet today. Although great effort has been made by pioneer workers and scientists in this field but still the exact model for the prediction and explanation of these properties is lagging. In the current work, we have proposed a new model to calculate the thermophysical properties like specific heat, melting enthalpy, and melting entropy of nanomaterials, which are calculated with the help of a cohesive energy model including shape effect in addition to structure of materials at the nano level. The relaxation factor due to the dangling bond at the surface of nanoparticles is taken under consideration. The obtained results using this model is fully consistent with the available experimental findings for the above said thermophysical properties for silver (Ag), copper (Cu), Palladium (Pd), Aluminium (Al), and Indium (In). This encouraging idea has also been used to predict the nature of variation of above mentioned important thermodynamic properties of other materials at their nano level.

DFT study on thermo-elastic properties of Ru2FeZ (Z = Si, Ge, Sn) Heusler alloys

2018 ◽  
Vol 32 (05) ◽  
pp. 1850045 ◽  
Author(s):  
Aneeza Iftikhar ◽  
Afaq Ahmad ◽  
Iftikhar Ahmad ◽  
Muhammad Rizwan
Keyword(s):  
Thermal Stability ◽  
Elastic Properties ◽  
Density Functional ◽  
Heusler Alloys ◽  
Longitudinal Mode ◽  
Transverse Mode ◽  
Functional Theory ◽  
Formation Energies ◽  
Thermal Stability Of ◽  
Temperature Melting

We studied the thermo-elastic properties of Ru2FeZ (Z[Formula: see text]=[Formula: see text]Si, Ge, Sn) Heusler alloys within the framework of density functional theory. Thermo-elastic properties corresponding to elastic modulus, anisotropy, phase stability, elastic wave velocities, thermal stability, Debye temperature, melting temperature, thermal conductivity and formation energy are calculated. The elastic constants C[Formula: see text] predict the structural and dynamical stabilities while the formation energies show thermal stability of the alloys at 0 K. Pugh’s and Poisson’s ratios display the ductile nature of alloys. All alloys are anisotropic and we also observed that Ru2FeSn is the hardest material than Ru2FeSi and Ru2FeGe. Moreover, longitudinal mode of vibrations are also observed and are maximum along [100], [110] and [111] directions than the transverse mode of vibrations.

Determination of effective properties of granite rock: A numerical investigation

MRS Advances ◽  
2018 ◽  
Vol 3 (37) ◽  
pp. 2159-2168
Author(s):  
Rehema Ndeda ◽  
S. E. M Sebusang ◽  
R. Marumo ◽  
Erich O. Ogur
Keyword(s):  
Elastic Properties ◽  
Close Agreement ◽  
Effective Properties ◽  
Volume Element ◽  
The Finite Element Method ◽  
Effective Elastic Properties ◽  
Spherical Inclusions ◽  
Periodic Microstructures ◽  
Crack Profile

ABSTRACTMacroscopic strength of the rock depends on the behavior of the micro constituents, that is, the minerals, pores and crack profile. It is important to determine the effect of these constituents on the overall behavior of the rock. This study seeks to estimate the effective elastic properties of granite using the finite element method. A representative volume element (RVE) of suitable size with spherical inclusions of different distribution is subjected to loading and the effective elastic properties determined. The results are compared to those obtained from analytical methods. The elastic properties are obtained in both the axial and transverse direction to account for anisotropy. It is observed that there is congruence in the results obtained both analytically and numerically. The method of periodic microstructures exhibits close agreement with the numerical results.

scholarly journals Theoretical Assessment of Thermodynamic Stability in Nanocrystalline Metallic Alloys

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3408 ◽  
Author(s):  
Antonio Mario Locci
Keyword(s):  
Thermodynamic Stability ◽  
Theoretical Description ◽  
Point Of View ◽  
Theoretical Point ◽  
Qualitative Comparison ◽  
Theoretical Approaches ◽  
Model Predictions ◽  
Cr System ◽  
Experimental Findings ◽  
Theoretical Assessment

Thermal stability in nanocrystalline alloys has been extensively explored while using both experimental and theoretical approaches. From the theoretical point of view, the vast majority of the models proposed in the literature have been implicitly limited to immiscible or dilute systems and thus lack the necessary generality to make predictions for different alloying interactions and in the case of intermetallic compounds formation. In this work, a general theoretical description for the case of binary W-based alloys is presented. It is shown that a critical value Ω ∗ of the interaction energy in the grain boundary Ω ( g b ) exists, such that the condition Ω ( g b ) < Ω ∗ can be regarded as a criterion for thermodynamic stability assessment. A procedure for calculating the value of Ω ∗ for each specific alloy is illustrated. A preliminary qualitative comparison between the model predictions and properly selected experimental findings taken from the literature and related to the W-Cr system is also provided.

scholarly journals A PHYSICAL THEORY OF ACID ANION DISPLACEMENT AND RECOVERY FOLLOWING EXERCISE

1944 ◽  
Vol 27 (3) ◽  
pp. 155-165
Author(s):  
Manuel F. Morales ◽  
Nathan W. Shock
Keyword(s):  
Experimental Data ◽  
Blood Plasma ◽  
Physical Theory ◽  
Close Agreement ◽  
Extracellular Fluid ◽  
Ion Concentration ◽  
Acid Anion ◽  
Simple Theoretical Model ◽  
Predicted Values ◽  
Anion Displacement

A simple theoretical model has been presented whose behavior duplicates the variation in bicarbonate ion concentration in the blood following exercise. Methods for the evaluation of the constants of rational equations to describe the concentration in muscle cells, in blood plasma, and in removal cells, of the anions produced in exercise have been devised. These methods have been applied to experimental data from 23 experiments, and a close agreement between the observed and theoretically predicted values for blood plasma has been found. From the mathematical analysis of the data values for permeability of acid anions produced in exercise have been estimated as 75 x 10–5 and 5.9 x 10–5 cm. per sec. between muscle cell and blood (extracellular fluid) and between blood plasma and removal cells respectively.

Melting entropy and enthalpy of metallic nanoparticles

2008 ◽  
Vol 62 (24) ◽  
pp. 3954-3956 ◽  
Author(s):  
M. Attarian Shandiz ◽  
A. Safaei
Keyword(s):  
Metallic Nanoparticles ◽  
Melting Entropy

scholarly journals THEORETICAL PREDICTION OF ELASTIC CONSTANTS FOR MgO

2013 ◽  
Vol 22 ◽  
pp. 24-27
Author(s):  
B. K. PANDEY ◽  
ANJANI K. PANDEY ◽  
CHANDRA KUMAR SINGH
Keyword(s):  
High Pressure ◽  
Theoretical Prediction ◽  
Elastic Properties ◽  
Pressure Dependence ◽  
Lower Mantle ◽  
Close Agreement ◽  
Elastic Parameter ◽  
Shearing Stress ◽  
Pressure Condition ◽  
Precise Knowledge

Precise knowledge of the elastic properties of MgO periclase, under high-pressure condition is therefore crucial for constructing the accurate mineralogical model of the Earth's lower mantle. In present work an attempt has been done to calculate the pressure dependence elastic properties such as isothermal bulk modules (KT), Young's modulus of elasticity Y and shearing stress G for geophysical MgO by using three deferent phenomenological EOS viz. the Born-Mayer EOS, Murnaghan EOS and Birch EOS. The result shows that the value of elastic parameter as calculated by using Murnughan EOS and Birch EOS shows close agreement with each other while Born-Mayer EOS shows deviation in calculated values.

scholarly journals Effect of Size and Shape on the Vibrational and Thermodynamic Properties of Nanomaterials

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
R. Kumar ◽  
G. Sharma ◽  
M. Kumar
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Size And Shape ◽  
Shape Dependence ◽  
Simple Theoretical Model ◽  
Model Predictions ◽  
Different Shapes ◽  
Debye Frequency ◽  
Good Agreement ◽  
Melting Entropy

A simple theoretical model is developed to study the size and shape dependence of vibrational and thermodynamic properties of nanomaterials. To show the real connection with the nanomaterials we have studied Debye temperature, Debye frequency, melting entropy, and enthalpy in different shapes, namely, spherical, nanowire, and nanofilm of -Fe, Sn, Ag, and In. The results obtained are compared with the experimental data. A good agreement between the model predictions and the experimental data supports the theory developed in the present paper.

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