A general closed expression is given for the isothermal minimum free energy of a linear viscoelastic material in terms of Fourier-transformed quantities. A oneparameter family of free energies is constructed, ranging continuously from the maximum to the minimum free energies. The simplest case of single component stress and strain tensors and a single viscoelastic function is considered in this...

We describe an analytical form of the Wulff plot construction procedure and derive a general expression for the surface energy from the three-dimensional equilibrium crystal shape in generalized orthogonal curvilinear coordinates. Particular expressions in Cartesian, spherical polar, and circular cylindrical coordinates are also presented. Corresponding results for a two-dimensional (2D) island...

Composite solid propellants were prepared with and without nano-alloys (Ti-Co, Ti-Ni, Ti-Zn), where nano-alloys used as catalyst. These nano-alloys are prepared by hydrazine reduction method. Catalytic properties of these nanomaterials were measured on Ammonium perchorate/hydroxyterminatedpolybutadiene propellant by thermogravimetery analysis and differential thermal analysis. Both experimental...

the thermal degradation of polyethylene (pe) was carried out in the absence and presence ofcatalystes x-zeolite and silica-alumina at different temperatures. the optimum pe/catalysisratio was 0.25:0.05 g/g, which produced highest degradation value. pe and pe/catalysis werecharacterized by thermogravimetric analysis. the thermal degradation properties of polymerhave been studied by infrared spec...

in this research chloroaiminium and copper phthalocyanine(clalpc and cupc)were purified twice, using entrained sublimitation techniques. ohmic contacts were made on the samples using the electrical properties of both (clalpc and cupc) were studied over a range of temperatures. the activation energies of these materials were measured using both forward and reverse current-voltage characteristic ...

The effect of ball milling on kinetics of the thermite reaction of 3Fe2O3 + 8Al powder mixture to synthesizeFe3Al-Al2O3 nanocomposite was investigated using differential thermal analysis. A model-free methodwas applied to the non-isothermal differential calorimetry (DSC) data to evaluate the reaction kineticsaccording to the Starink method. The activation energy of the thermit...

Composite solid propellants were prepared with and without nano-alloys (Ti-Co, Ti-Ni, Ti-Zn), where nano-alloys used as catalyst. These nano-alloys are prepared by hydrazine reduction method. Catalytic properties of these nanomaterials were measured on Ammonium perchorate/hydroxyterminatedpolybutadiene propellant by thermogravimetery analysis and differential thermal analysis. Both experimental...

This paper describes a hybrid ab initio quantum mechanical/molecular mechanics (QM/MM) method for calculating activation free energies of chemical reactions in solution, using molecular mechanics force fields for the solvent and an ab initio technique that incorporates the potential from the solvent in its Hamiltonian for the solute. The empirical valence bond (EVB) method is used as a referenc...

Two possibile applications of the optimized expansion for the free energy of the quantum-mechanical anharmonic oscillator are discussed. The first method is for the finite temperature effective potential; the second one, for the classical effective potential. The results of both methods show a quick convergence and agree well with the exact free energy in the whole range of temperatures.