# thesIt

• #### Arif 06:32:12 am on August 22, 2010 | 0 | # | Tags: basic, density, wikipedia

Density of a material is defined as its mass per unit volume.
ρ (in some countries i.e. USA) is also defined as weight per unit volume
Units: (kg/m³), g/cm³

• #### Arif 12:06:03 pm on February 19, 2010 | 0 | # | Tags: angular velocity, density, equation, interfacial tension, spinning drop, wikipedia

Interfacial tension and centrifugal forces balanced at mechanical equilibrium.

centrifugal-IFT equilibrium

Interfacial tension of any liquid that gives a shape very close to a cylinder at the equilibrium point, can be estimated using Vonnegut’s expression:

$\sigma=\frac{\Delta\rho\omega^2}{4}R^3$

ω : angular velocity; (radians per second, degrees per second, revolutions per second)

Δρ : difference between two fluid: the less-dense and the dense

• #### Arif 09:23:39 pm on February 18, 2010 | 0 | # | Tags: density, interfacial tension, Mansoori 1990, prediction, reference

Statistical Mechanics Basis of Macleod’s Formula. M.-E. BOUDH-HIR and G.A. MANSOORI. Journal of Physical Chemistry, Volume 94, pp.8362-8364, 1990.

The famous formula of Macleod, relating the surface tension of a liquid in equilibrium with its own vapor to the one-particle densities in the two phases of the system, is derived. Proved using the statistical- mechanical definition of the surface tension.

(Later on Mansoori worked with Escobedo)

 StatMechBasisOfMcLeodEquation.pdf

• #### Arif 06:19:05 pm on January 1, 2010 | 0 | # | Tags: density, equation, Escobedo 1998, interfacial tension, Kumar 2005, parachor, prediction, pure compound, reference, statistical

Escobedo and Mansoori (AIChE J. 42(5): 1425, 1996) Found original paper: check Escobedo 1996

The proposed 1996 paper relates the surface tension of mixtures to bulk-phase concentrations and properties (i.e. densities). Surface tension of pure organic fluids σ:

$\sigma=[P(\rho_l-\rho_v)^4]$

The two ρ are densities: liquid and vapour.

They introduced parachor (P), a new expression, derived from statistical mechanics (from Macleod equation) which represents the experimental surface tension of 94 different organic compounds within 1.05 AAD% (average absolute deviations).

(Kumar 2005) It expresses the surface tension of a liquid in equilibrium with its own vapour. Historical reference for parachor cited here: Macleod, Sugden, Quayle, Escobedo.