Other properties of liquids

The viscosity, or more precisely, the coefficient of viscosity, of a liquid measures the resistance to flow under stress. Because the molecules of liquid are very close to one another, a liquid is much more viscous than a gas. The close spacing and the intermolecular forces both contribute to this resistance to flow. Viscosity is discussed in somewhat greater detail in Chapter 30. 

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The fundamental property of liquid surfaces is that they tend to contract to the smallest possible area. This property is observed in the spherical form of small drops of liquid, in the tension exerted by soap films as they tend to become less extended, and in many other properties of liquid surfaces. In the absence of gravity effects, these curved surfaces are described by the Laplace equation, which relates the mechanical forces as (Adamson and Gast, 1997 Chattoraj and Birdi, 1984 Birdi, 1997) ... 

Further, each catalyst had a significant effect on the position of double bonds and olefinic content. The catalyst also affects the other properties of liquid fraction such as density. A decrease in density of the liquid indicates low average molecular weight. They also observed that the pour points were lower with ZSM-5 and FCC catalyst than with CRT. Maximum distillation temperatures of liquid products were lower after catalytic cracking than for thermal cracking. 

It is possible to investigate other properties of liquid surfaces by Laplace s method, and much of the treatment of surface tension in physic works is concerned with such mathematical calculations, but the matter will not be carried further here, since the fundamental assumptions in the theory are questionable. Einstein showed that the radius of molecular action is of the order of the molecular diameter, so that only actually adjacent molecules will exert forces on one another, and the surface layer is a particular phase which is one molecule in thickness. This idea has received much support from experiments on surface films by Langmuir, mentioned in 19.VIII G, and it is now part of the stock-in-trade of physical chemists. Raman and Ramdas, from the behaviour of polarised light reflected from a very clean liquid surface, concluded that the surface layer was about 10 cm. thick, i.e. unimolecular. 

Since many other properties of liquids and solids depend on pressure, one could think of many more different types of sensor for pressure measurement. However, the sensors discussed so far seem to meet most of the demands of typical hydraulic systems. 

PREFREEZING EFFECTS IN THE VISCOSITY AND OTHER PROPERTIES OF LIQUIDS. 

Ubhelohde L (1937) The principle of the suspended level applications to the measurement of viscosity and other properties of liquids. Ind Eng Chem Anal Ed 9(2) 85-90... 

B. Other Properties of Liquid at Negative Pressure VII. Perspectives... 

To use the model to predict other properties of liquid crystal dimers, for example, the N-I transition temperature and the temperature dependence of the order parameter it is necessary to make an additional approx-imation. This is to relate the strength parameter Xa for a mesogenic group to the orientational order of the nematic mesophase. By analogy with the Maier-Saupe theory [63] and the extension of this to multicomponent mixtures [68] it is assumed that... 

The other vital consideration affecting the possibility of solidification and influencing also almost all of the other properties of liquid helium is its very high zero-point energy. In quantum mechanics, the lowest permitted kinetic energy for a particle is not necessarily zero. If a particle of mass m is confined to a volume F, then its minimum kinetic energy, or zero-point energy, is... 

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