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.

Size and shape dependence of Debye temperature and Raman frequency of nanomaterials

2015 ◽  
Vol 29 (04) ◽  
pp. 1550004
Author(s):  
Raghuvesh Kumar ◽  
Sandhya Bhatt ◽  
Munish Kumar
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Debye Temperature ◽  
Experimental Studies ◽  
Raman Frequency ◽  
Size And Shape ◽  
Shape Dependence ◽  
Simple Theoretical Model ◽  
Good Agreement

A simple theoretical model is developed to study the size and shape dependence of Debye temperature and Raman frequency of nanomaterial. We have studied the effect of size and shape on Debye temperature of nanocrystalline Fe , Co , Al and Ag . The model is extended to study the effect of size and shape on the Raman frequency of nanocrystalline SnO 2, CeO 2 and CdSe . The results obtained are compared with the available experimental data. A good agreement between the theory and experimental data supports the validity of the model developed. We also report the results for nanowire and nanofilm in the absence of experimental data, which may help the researchers engaged in the experimental studies.

Viscosity Models Based on Network Theory for Polymer Melts

2010 ◽  
Vol 129-131 ◽  
pp. 1244-1247
Author(s):  
Hai Hang Xu ◽  
Lei Zhong
Keyword(s):  
Experimental Data ◽  
Kinetic Equation ◽  
Constitutive Equation ◽  
Polymer Composites ◽  
Network Theory ◽  
Polymer Melts ◽  
Structure Parameter ◽  
Viscosity Models ◽  
Model Predictions ◽  
Good Agreement

New shear and extensional viscosity models based on Fredrickson kinetic equation coupled with Dewitt constitutive equation were established to predict viscosities of polymer melts. The experimental data of 125°C LDPE and LDPE filled with 35% glass beads reported from references were compared with the model predictions. The predictions showed good agreement with the measurements. The models are simple and easy to use. Because they contain no structure parameter, they are capable to describe the viscosities of pure polymer and polymer composites.

POWER AND EFFICIENCY OF F1-ATPase MOLECULAR MOTOR

2012 ◽  
Vol 11 (01) ◽  
pp. 1240003
Author(s):  
J. M. SANCHO ◽  
RUBEN PEREZ-CARRASCO
Keyword(s):  
Experimental Data ◽  
Angular Velocity ◽  
Molecular Motor ◽  
Transition Rates ◽  
Motor Power ◽  
F1 Atpase ◽  
Flashing Ratchet ◽  
Model Predictions ◽  
Good Agreement ◽  
Ratchet Potential

We present the study of the energetics of the F1-ATPase rotatory molecular motor. The dynamics of this machine are described by a overdamped Langevin equation with a dichotomous flashing ratchet potential whose transition rates are controlled by an analysis of the chemical and physical steps. The model predictions on the observable angular velocity are in good agreement with the experimental data. Inspired by these results we extend our approach to study the energetics of this motor. Power and efficiency are analyzed for different experimental situations which can be tested in experiments.

scholarly journals Sn-Ni-Bi liquid phase thermodynamic properties

2011 ◽  
Vol 9 (1) ◽  
pp. 149-156 ◽  
Author(s):  
Nikolina Milcheva ◽  
Jolanta Romanowska ◽  
Gueorgui Vassilev
Keyword(s):  
Experimental Data ◽  
Liquid Phase ◽  
Thermodynamic Properties ◽  
Binary Systems ◽  
Isopiestic Method ◽  
Miscibility Gap ◽  
Calphad Approach ◽  
Activity Data ◽  
General Solution Model ◽  
Good Agreement

AbstractExperimental data of bismuth activity coefficients at 1773 K were obtained by isopiestic method and compared to calculated values. Thermodynamic properties of the Sn-Ni-Bi liquid phase were estimated by means of the general solution model and by the methods of Kohler. Description of the ternary liquid phase (Gibbs excess energy dependence on the temperature and the composition) was achieved by using available thermodynamic data of the constitutive binary systems (Ni-Bi, Sn-Bi, Sn-Ni). A comparison between calculated quantities and experimental data wasconducted. The present assessment with thermodynamically optimized values of the system Sn-Ni-Bi (obtained by the CALPHAD approach) was in good agreement. The suggested appearance of a liquid phase miscibility gap at high temperatures is in agreement with the experimental bismuth activity data and with the assessed thermochemical functions.

Evaluation of the Thermodynamic Properties and Phase Equilibria of the Ordered γ’ and Disordered γ Phases in the Ni-Al-Ta System

2002 ◽  
Vol 755 ◽  
Author(s):  
Shihuai Zhou ◽  
Long-Qing Chen ◽  
Rebecca A. MacKay ◽  
Zi-Kui Li u
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Gibbs Energy ◽  
Phase Equilibria ◽  
Phase Diagrams ◽  
Gibbs Energy Function ◽  
Ternary Interaction ◽  
Two Phases ◽  
Rich Side ◽  
Good Agreement

ABSTRACTThe phase equilibria and thermodynamic properties of the ternary Ni-Al-Ta system on Ni-rich side were analyzed. Thermodynamic descriptions of the liquid, γ-fcc, γ'-L12, and π-Ni6AlTa phases were obtained using the CALPHAD (CALculation of PHase Diagrams) technique. The thermodynamics of γ-fcc and γ'-L12 phases were modeled with a single Gibbs energy function taking into account the crystallographic relation between the two phases. The ternary interaction parameters of the liquid and fcc phases were also determined. The calculated phase diagrams of the ternary Ni-Al-Ta system show a good agreement with experimental data.

A theoretical model to study melting of metals under pressure

2015 ◽  
Vol 29 (27) ◽  
pp. 1550161 ◽  
Author(s):  
Kuldeep Kholiya ◽  
Jeewan Chandra
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Melting Temperature ◽  
Present Model ◽  
Melting Curve ◽  
Experimental Result ◽  
Thermal Equation ◽  
Simple Theoretical Model ◽  
Pressure Melting ◽  
Good Agreement

On the basis of the thermal equation-of-state a simple theoretical model is developed to study the pressure dependence of melting temperature. The model is then applied to compute the high pressure melting curve of 10 metals (Cu, Mg, Pb, Al, In, Cd, Zn, Au, Ag and Mn). It is found that the melting temperature is not linear with pressure and the slope [Formula: see text] of the melting curve decreases continuously with the increase in pressure. The results obtained with the present model are also compared with the previous theoretical and experimental data. A good agreement between theoretical and experimental result supports the validity of the present model.

scholarly journals Thermodynamics and phase diagram calculation of the binary arsenic-tellurium system in the framework of the generalized lattice model

2021 ◽  
Vol 2052 (1) ◽  
pp. 012015
Author(s):  
N V Gerasimov ◽  
M A Zakharov
Keyword(s):  
Experimental Data ◽  
Phase Diagram ◽  
Thermodynamic Properties ◽  
Thermodynamic Parameters ◽  
Lattice Model ◽  
Binary Phase Diagram ◽  
Phase Diagram Calculation ◽  
Binary Phase ◽  
Good Agreement

Abstract In this work we describe how to efficiently calculate thermodynamic properties and T-x diagram of binary As-Te solution in the generalized lattice model. All the thermodynamic parameters of the As-Te solution are obtained within framework of the generalized lattice model. The binary phase diagram of As-Te system is calculated and good agreement with experimental data is obtained.

Performance Analysis and Optimization of a Dual Warhead System

2012 ◽  
Vol 13 (1) ◽  
Author(s):  
Xiao-Jun Guo ◽  
He-Ming Wen
Keyword(s):  
Experimental Data ◽  
Performance Analysis ◽  
Analytical Model ◽  
Present Model ◽  
Shaped Charge ◽  
Weapon Systems ◽  
Model Predictions ◽  
Modern Warfare ◽  
Good Agreement ◽  
Concrete Target

AbstractIn modern warfare earth penetrating weapons are often used to defeat enemy’s hardened and deeply buried targets such as aircraft shelters and bunkers. A dual warhead system (DWS) is one of such weapons composed of a forward shaped charge (FSC) and a following through warhead (FTW). In this paper, an analytical model is first proposed to analyze the penetration of an FTW into concrete targets with pre-drilled holes and a DWS is then optimized in order to achieve its best penetration performance. The effects of various parameters on the performance of a dual warhead system penetrating a concrete target are delineated. It transpires that the present model predictions are in good agreement with available experimental data and that the results obtained may be useful for designing such weapon systems.

SIZE AND TEMPERATURE EFFECT ON THERMAL EXPANSION COEFFICIENT AND LATTICE PARAMETER OF NANOMATERIALS

2013 ◽  
Vol 27 (25) ◽  
pp. 1350180 ◽  
Author(s):  
RAGHUVESH KUMAR ◽  
GEETA SHARMA ◽  
MUNISH KUMAR
Keyword(s):  
Experimental Data ◽  
Thermal Expansion ◽  
Temperature Dependence ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Size Dependence ◽  
Coefficient Of Thermal Expansion ◽  
Lattice Parameter ◽  
Model Predictions ◽  
Good Agreement

A simple theoretical model is developed to study the effect of size and temperature on the coefficient of thermal expansion and lattice parameter of nanomaterials. We have studied the size dependence of thermal expansion coefficient of Pb , Ag and Zn in different shape viz. spherical, nanowire and nanofilm. A good agreement between theory and available experimental data confirmed the model predictions. We have used these results to study the temperature dependence of lattice parameter for different size and also included the results of bulk materials. The temperature dependence of lattice parameter of Zn nanowire and Ag nanowire are found to present a good agreement with the experimental data. We have also computed the temperature and size dependence of lattice parameter of Se and Pb for different shape viz. spherical, nanowire and nanofilm. The results are discussed in the light of recent research on nanomaterials.

Analysis of the Equilibrium Approximation in Chemical Ablation of Thermal Protective Systems

2012 ◽  
Author(s):  
B. W. Barr ◽  
O. A. Ezekoye
Keyword(s):  
Experimental Data ◽  
Complex Surface ◽  
Damkohler Number ◽  
Damköhler Number ◽  
Graphite Oxidation ◽  
Model Predictions ◽  
Surface Equilibrium ◽  
Carbon Combustion ◽  
New Formulation ◽  
Good Agreement

A quasi-steady-state ablation model is used to investigate the behavior of thermochemically ablating systems in equilibrium and nonequilibrium surface thermochemistry regimes. The model is simplified to allow extraction of relevant nondimensional parameters and comparison with existing experimental data on solid carbon combustion. Good agreement is found between model predictions and experimental data, and the data and model are collapsed in terms of the B number and surface Damkohler number. A new formulation for the surface Damkohler number is proposed, and a relationship between the B number and this Damkohler number is derived for the surface equilibrium and nonequilibrium regimes. The Damkohler formulation is applied to the reentry scenario, and the behavior of the B number in this context is explored. Nondimensional parameters governing behavior in the nonequilibrium regime are determined for graphite oxidation, and the results are extrapolated to more complex surface thermochemistry conditions.

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