Capillarity action

Fiber capillarity action The attraction between molecules, similar to surface tension, which results in the rise of a liquid in fibers, as could occur in RJPs, etc. 

Rising damp from both soil and underground water is a source of salts that rise by capillarity action. 

Surface evaporation can be a limiting factor in the manufacture of many types of products. In the drying of paper, chrome leather, certain types of synthetic rubbers and similar materials, the sheets possess a finely fibrous structure which distributes the moisture through them by capillary action, thus securing very rapid diffusion of moisture from one point of the sheet to another. This means that it is almost impossible to remove moisture from the surface of the sheet without having it immediately replaced by capillary diffusion from the interior. The drying of sheetlike materials is essentially a process of surface evaporation. Note that with porous materials, evaporation may occur within the solid. In a porous material that is characterized by pores of diverse sizes, the movement of water may be controlled by capillarity, and not by concentration gradients. 

H. G. J. Mol, H.-G. Janssen and C. A. Cramers, Use of open-tubular trapping columns for on-line extr action-capillar y gas cliromatography of aqueous samples , 7. High Resolut. Chromatogr. 16 413-418 (1993). 

KapiUarititt, /. capillarity. Kapillaritittsanziehung./. capillary attraction. Kapillar-kraft,/, capillary force, -kreislauf, n. capillary circulation, -rohr, -rohrchen, n, -rohre, /. capillary tube, -spaonung, /. capillary tension, -stromung, /. capillary flow, -versuch, m. capillary test or experiment. -wirkung./. capillary action. 

In the older theory of capillary action(1), developed by Laplace T. Young (1805), Gauss (1830), and Poisson (1831), no attention was paid to the possibility of thermal changes attending the alteration of surface at constant temperature. That such changes must exist was first demonstrated by Lord Kelvin (2) (1859), and the theory of capillarity Was developed more particularly from the thermodynamic standpoint in the masterly treatise of Willard Gibbs (8) (1876). 

Initially, both the NWP and WP are randomly distributed throughout the CL porous structure such that the desired NWP saturation is achieved. The initial random distribution of the liquid water phase (i.e. NWP) in the otherwise air (i.e. WP) occupied CL closely represents the physically perceived scenario of liquid water generation due to the electrochemical reaction at different catalytically active sites within the CL structure and subsequent transport by the action of capillarity. In the present numerical experiment, the CL domain is assumed to be bounded by walls in the span-wise directions and periodic in the thickness direction. 

Mixtures of powders of two materials sinter very rapidly if one of them melts at the sintering temperature. Initially capillary action causes the liquid phase to rapidly wet the solid phase, causing an initial contraction. Then as the solid phase dissolves in the liquid it is rapidly transported to locations that decrease the pore volume. Carbide tool material is made from a mixture of cobalt and tungsten carbide powders sintered below the melting point of cobalt. The volume fraction liquid must be limited so capillarity can retain the shape during sintering. 

Kitamori s group has proposed selective chemical surface modification utilizing capillarity (called the capillarity restricted modification or CARM method) (Hibara et al., 2005). In the CARM method, a microchannel structure combining shallow and deep microchannels and the principle of capillarity are utilized. The procedures are shown in Figure 19. A portion of an ODS/toluene solution (lwt%) is dropped onto the inlet hole of the shallow channel, and the solution is spontaneously drawn into this channel by capillary action. The solution is stopped at the boundary between the shallow and deep channels by the balance between the solid-liquid and gas-liquid interfacial energies. Therefore, the solution does not enter the deep channel. It remains at the boundary for several minutes and is then pushed from the deep channel side by air pressure. 

Since chromatographic migration rates depend on the amount of liquid phase and on the liquid velocity, the above noted gradients, established by the actions of capillarity, have important chromatograhic effects [14]. More details on the chromatographic consequences of capillary flow can be found in the literature (12) and in subsequent chapters. 

He explained the result as follows In the combustion of a candle, the radiant heat from the flame first melts the wax, and tills, by the capillary action of the wick, rises into the flame. It is thus evident that the rate of consumption of the wax is entirely dependent upon the capillarity of the wick, provided the heat radiated from the flame is sufficient to maintain the supply of liquid fuel and to volatilise it on its arrival near the apex of the cotton. Since capillary action is not affected by variations hi atmospheric pressure, and as the temperature is almost independent of the same influence, it is clear that neither factor will vary, and the above constancy in rate of combustion is to be anticipated. 

If the cylinder is extremely narrow, a thin film of water will be drawn upward. Narrow tubes are called capillary tubes. This movement of a liquid such as water is called capillary action, or capillarity. Capillary action helps explain how paper towels can absorb large amounts of water. The water is drawn into the narrow spaces between the cellulose fibers in paper towels by capillary action. In addition, the water molecules form hydrogen bonds with cellulose molecules. These same factors account for the absorbent properties of disposable diapers. Water is drawn from the surface of the diaper to the interior by capillary action. The diaper can absorb about 200 times its mass in fluid. 

These examples of the rising of liquids in narrow tubes are illustrations of capillarity, or, as it is sometimes called, capillary action. Capillarity results from the competition between the interparticle attractive forces between the molecules of liquid and the attractive forces between the liquid and the tube that contains it. 

It is advantageous to fill the channels as soon as possible after device assembly. The PDMS stays hydrophilic for about half an hour. During this time, the channels fill easily due to the combined action of hydrophilicity and capillarity, so that bubble formation is reduced. Air bubbles can become a major problem as they cause unstable flow profiles. Make sure that no air bubbles are trapped inside when Ailing the syringes and connecting the tubing. 

Capillary actions or capillarity is a scientific topic concerning the equilibrium shape of interfaces in contact with a solid wall, in particular, in thin tubes or capillaries. For instance, for water in... 

Fiber capillary action Apart from improved adsorption of biological fluids thanks to fiber high surface ratio, capillary action of fibers also contributes to cells adhesion onto the fibrous implantable medical device. Capillarity is the action by which pores in a solid transport liquid on contact, so that tissue fluids transfer from the wet end to the dry end. The kinetics of the fluid transport are governed by the surface tension... 

---