Capillary break

The finer-grained layer of a capillary barrier cover system has the same function as the monolithic soil layer that is, it stores water until it is removed from the soil by evaporation or transpiration mechanisms. The coarser-grained layer forms a capillary break at the interface of the two layers, which allows the finer-grained layer to retain more water than a monolithic cover system of equal thickness. Capillary forces hold the water in the finer-grained layer until the soil near the interface approaches saturation. If saturation of the finer-grained layer occurs, the water will move relatively quickly into and through the coarser-grained layer and to the waste below. 

Figure 4. Mechanically ventilated wood frame dwelling on a monolithic slab, natural draught ventilation of the capillary breaking layer by ducts through the edge beam.

Figure 38-7. Influence of the capillary break (—) and cohesion break ( ) on the spinnable length L of the fibers as a function of the fiber production rate v and viscosity rj. (—) Effect observed when capillary and cohesion breaks overlap. (After A. Ziabicki.)...

Also Rayleigh time scale for capillary break up (t ) =... 

It is generally thought that blood capillaries break in bulb of hair root and drugs are taken into the hair while matrix cells produced in hair papilla grow and are keratinized. The drugs are contained mainly in hair cortex and amount to 50-100 ng mg single... 

From the relation L=f(vij) it is obvious that the spinnability is governed by two processes, namely the cohesive break (or the swell effect) and the melt break (capillary break, melt fracture). According to Section 11.3.1, a certain amount of elastic energy can be stored in all viscoelastic fluids. This phenomenon leads, among others, to the Barus effect. 

As discussed in Chapter 3, Breckenridge et al. [1981] developed a capacitance-type sensor of very flat response, by which they detected AE waves due to a break of glass capillary shown in Fig. 7.4. Later, the capillary break was replaced by the pencil-lead break by Hsu [1978]. As compared Fig. 7.3 with Fig. 7.4, first time, they showed that AE wave detected by the flat-type sensor due to the step-function force is actually identical to Lamb s solution due to the surface pulse. It was also demonstrated that Lamb s solution due to a buried pulse could be obtained by applying the force at the bottom of the block in Fig. 3.10. Thus, it is clarified by them that the displacement observed by the flat-type sensor due to capillary break or pencil-lead break is identical to G 33(x,yo,t). This implies that Green s function of the specimen can be empirically obtained by just applying the pencil-lead break and recording the displacements. 

In arid regions, impermeable geomembranes can be used as capillary breaks to stop the upward movement of salts where they would destroy the road surface. Geomembranes also can be used to prevent the formation of ice lenses in permafrost and other frost-prone regions. The geomembrane must be located below the frost line and above the water table. 

For example, the ingress of a rising water table can be restricted by a cross-slope drainage geocomposite with a GCL layer or geomembrane placed above to act as a capillary break in the water flow. A second drainage geocomposite above the impermeable layer would then remove surface... 

A typical immersion experiment may be described [15-18], The solid sample is outgassed in a glass bulb that has a capillary break-seal. The sealed ampoule is attached to a push-rod, which may also be used to drive a stirrer, and placed in the immersion liquid inside the calorimeter vessel (Fig. 3). Depression of the plunger breaks the seal, the solid is wetted by the surrounding liquid, and the heat evolved is detected. The experimental heat geip comprises three components, only one of which is relevant to the immersion effect. The correction term Qcon originates from the breaking of the ampoule and the subsequent heat of evapora-... 

Kapillarbruch capillary breaking, capillary fracture (fibers)... 

HaargefaC capillary air bleed/ boiling capillary/ air leak tube dist Siedekapillare capillary blotting Diffusionsblotting capillary breaking/ capillary fracture (fibers) Kapillarbruch... 

The experimental tensile strengths of liquids were reported by Briggs who employed a "Z-shaped capillary tube, open at both ends, rotating in the Z plane about an axis passing throu the center of the Z and perpendicular to the plane. The liquid menisci are located in the bent-back short arms of the Z. The speed of rotation is increased gradually until the liquid in the capillary breaks." " ... 

Spinning can be carried out successfully only when the liquid is spinnable, i.e. capable of being substantially extended prior to solidification. The lack of spinnability of solutions may be due to capillary break-up arising from a high ratio of the surface tension and viscosity for melts, this ratio is typically less than 10 m s" and this mechanism may be disregarded. The other reason for the lack of spinnability may be either ductile or brittle failure of the liquid jet. In practice, the spinnability is often limited by polymer contamination rather than by fundamental material properties. 

The question is what value We will have. Inspection of Figure 2.4, and taking the capillary break-up mechanism into accoimt, leads to the conclusion that We will rarely be over unity, since it is very likely that the flow will have an elongational component. This is because the flow in eddies is always, for a considerable part, circular. Effective We may even be as low as 0.1, but since the constant implied in eqn. (2.14) is unknown anyway, it makes little sense to use eqn. (2.23) as more than a scaling law. 

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