نتایج جستجو برای: liquid density

تعداد نتایج: 615622  

2001
Vincent K. Shen Pablo G. Debenedetti

Density-functional theory is used to study homogeneous bubble nucleation in the stretched Lennard-Jones liquid. We show that the ratio of density-functional to classical nucleation theory free energy barriers should scale with the quantity Dm/Dmspin , the difference in chemical potential between the bulk superheated and the saturated liquid divided by the chemical potential difference between t...

1996
C. J. Roberts Pablo G. Debenedetti

A molecular model of network-forming liquids has been formulated in terms of a lattice fluid in which bond formation depends strongly on molecular orientations and local density. The model has been solved in the zerothand first-order approximations for molecular and bond geometries similar to water or silica. Results are presented in the form of fluid-phase boundaries, limits of stability, and ...

2009
Y. Sun C. Beckermann

Phase-field simulations are used to examine tip velocity and shape selection in free dendritic growth of a pure substance into an undercooled melt in the presence of a density change between the solid and liquid. The dendrite is assumed to grow two-dimensionally inside a Hele-Shaw cell. The phase-field model is coupled with a previously developed two-phase diffuse interface model to simulate th...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2004
A Roshi G S Iannacchione P S Clegg R J Birgeneau

High-resolution ac calorimetry has been carried out on dispersions of aerosils in the liquid crystal octyloxycyanobiphenyl (8OCB) as a function of aerosil concentration and temperature spanning the crystal to isotropic phases. The liquid crystal 8OCB is elastically stiffer than the previously well studied octylcyanobiphenyl (8CB)+aerosil system and so general quenched random-disorder effects an...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2003
Giancarlo Franzese Manuel I Marqués H Eugene Stanley

We study a model for water with a tunable intramolecular interaction J(sigma), using mean-field theory and off-lattice Monte Carlo simulations. For all J(sigma)> or =0, the model displays a temperature of maximum density. For a finite intramolecular interaction J(sigma)>0, our calculations support the presence of a liquid-liquid phase transition with a possible liquid-liquid critical point for ...

2011
Christopher Woodward James Lill

Convective instabilities responsible for misoriented grains (freckle defects) in directionally solidified turbine airfoils are produced by variations in liquid–metal density with composition and temperature across the solidification zone. Here, fundamental properties of molten Ni-based alloys, required for modeling these instabilities, are calculated using ab initio molecular dynamics simulatio...

2007
Mauricio Girardi Marcia Szortyka Marcia C. Barbosa

We investigate the relation between thermodynamic and dynamic properties of an associating lattice gas (ALG) model. The ALG combines a three dimensional lattice gas with particles interacting through a soft core potential and orientational degrees of freedom. From the competition between the directional attractive forces and the soft core potential results two liquid phases, double criticality ...

Journal: :Langmuir : the ACS journal of surfaces and colloids 2016
Wei-Shan Chiang Emiliano Fratini Piero Baglioni Jin-Hong Chen Yun Liu

Methane adsorption in model mesoporous silica materials with the size range characteristic of shale is studied by small-angle neutron scattering (SANS). Size effect on the temperature-dependent gas adsorption at methane pressure about 100 kPa is investigated by SANS using MCM-41 and SBA-15 as adsorbents. Above the gas-liquid condensation temperature, the thickness of the adsorption layer is fou...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد علوم دارویی - دانشکده داروسازی 1392

گیاهان دارویی در طول تاریخ بشر در درمان بیماریها استفاده می شدند.از این رو ما در این پایان نامه اثر آنتی باکتریال عصاره تام و فراکسیون های اتردوپترولی و آبی حاصل از گیاه calotropis procera را بررسی کردیم.در این مطالعه روش ما برای عصاره گیری روش liquid-liquid fraction بودوعصاره تامو فراکسیون های اتر دوپترولی وآبی تهیه شد.برای روش میکروبی از روش انتشار در محیط آگار استفاده کردیمو به روش چاهک پلیت...

Journal: :The Journal of chemical physics 2014
Fabio Leoni Giancarlo Franzese

Confinement can modify the dynamics, the thermodynamics, and the structural properties of liquid water, the prototypical anomalous liquid. By considering a generic model for anomalous liquids, suitable for describing solutions of globular proteins, colloids, or liquid metals, we study by molecular dynamics simulations the effect that an attractive wall with structure and a repulsive wall withou...

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