Dimples, separators

Adsorbent sheet bonded to plate. Dimples separate sheets and allow free flow of vapour... 

B. The direct identification of such microscopic fracture modes as transgranular cleavage, radial fracture, intergranular separation or ductile dimpled rupture, was shown to be considerably more dependable by SEM than by OM... 

Another model system, which is quite typical for SFM measurements, consists of a pair of sharp spikes separated by distance d. The dimple in Fig. 20b can be calculated as Az=d2/8R, e.g. for Az=0.1 nm, the minimum detectable separation will be 2.8 nm. 

Ten minutes following injection of the droplets a photograph was taken. The small droplets (diameter less than lOOvttn) were separated with a thick film while on the hat of certain of the larger droplets there could be seen a dimple illustrative of a thinning film. 

Instead of using a furrowed or dimpled membrane support plate, Sobey [41] observed that a single flow deflector in a flat membrane channel could produce many vortices under oscillatory flow conditions, an effect named the vortex wave. An important feature of the vortex wave is that it could occur under low crossflow velocity conditions or with laminar flow so that it can be used for shear-sensitive fluids. Millward et al. [42] tested the effect of vortex waves on plasma filtration with waves produced by flow deflectors with cross-sectional area of 1 x 1 mm in a 2.25 mm high channel as shown in Figure 8.22. The aim was to improve membrane applications for the separation of plasma from cellular blood components for both donor... 

FIGURE 5.36 Main stages of formation and evolution of a thin liquid film between two bubbles or drops (a) mutual approach of slightly deformed surfaces (b) at a given separation, the curvature at the center inverts its sign and a dimple arises (c) the dimple disappears, and eventually an almost plane-parallel film forms (d) due to thermal fluctuations or other disturbances the film either ruptures or transforms into a thinner Newton black film (e), which expands until reaching the final equilibrium state (f). 

When a certain small separation, h, the inversion thickness, is reached, the sign of the curvature in the contact of the fluid particles (drops, bubbles) changes. A concave lens-shaped formation called a dimple is formed (see Frankel and Mysels" ). This stage is also observed for asymmetric fllms." A number of theoretical studies have described the development of a dimple at the initial stage of film thinning The inversion thickness can be calculated from a simple equation in which the van der Waals interaction is explicitly taken into account (see Section 5.4.2)i 4,43i,465... 

Beysens, D., Guenoun, P., Sibille, P., and Kumar, A. (1994) Dimple and nose coalescences in phase-separation processes, Phys. Rev. E 50, 1299. 

In the original design of the Atucha-1 charmel, the main shroud tube enclosing the fuel assembly was made of Zircaloy 4 and comprised a seam-welded tube (108.2-mm inside diameter and 1.6- or 1.72-mm in wall thickness). A thin (0.1-mm wall thickness) Zircaloy tube, dimpled to maintain separation, surrounded the shroud tube between it and the seam-welded Zircaloy 4 insulation tube (0.4-mm wall thickness). These were attached to austenitic stainless steel end fittings. The bottom end fitting sat in the bottom plenum lattice port allowing a small gap for the circulation of heavy water into the moderator space. The upper end was fastened to the upper plenum. 

In the example of poor joint design, the distorted metal creates a favourable thick glue line over most of the joint, but minimises the thickness at the critical joint ends. If a separation dimple is placed in the middle of the joint (the low stress area), this will control the glue line without compromise of joint strength (see Fig. 39). 

Any iron present in the leach solution is removed by precipitation as goethite (FeOOH). The solution is then purified by cementation with lead powder to remove copper, silver, bismuth, arsenic and antimony, leaving impurities such as zinc, which do not co-deposit with lead. The purified solution is electrolysed in a diaphragm cell, which uses a coated copper cathode and a titanium mesh anode coated with ruthenium and iridium oxides. An ion permeable membrane separates the cathode and anode compartments. The cathode is fabricated from a dimpled copper sheet coated with an inert adhesive sheet between the dimples, leaving numerous sites of high current density to promote dendritic growth of the lead deposit. The crystalline lead falls from the cathode and is collected in the base of the cell. 

In the last few years, great advances have been made regarding SWCNTs separation, based on metallicity. Positive developments were made in controlling and optimizing the generation of CNTs, as well as its separation and purification via chirality and metallicity (Hongjie et al. 2002 Rodney et al. 2002). Therefore, SWCNTs were formed as a small amount of metal particle placed on a dimple... 

Dimple is formed at a certain small separation between the fluid particles (see Fig. 33b and Sec. VII.B). The dimple initially grows, but later becomes unstable and quickly outflows. 

When membranes fuse, the so-called stalk hypothesis suggests that the intermediate hemifusion state (Fig. 6.4c) comprises a structure in which proximal monolayers layers are connected by a bent stalk and the distal layers are pulled towards each other, thus forming a dimple (see also Fig. 6.5) The stalk model has been supported by theoretical and experimental observations. The fusion of model membranes appears to occur via the same series of fusion intermediates as those in vivo, although the approach of membranes is not Rab/SNARE mediated but is driven by reduced bilayer repulsion forces arising from hydration, electrostatic interactions, thermal fluctuations (Helfrich interaction) or osmotic stress. Membrane fusion is also promoted by defects introduced into the membrane by lateral phase separation (for example of lipid rafts, see above), high spontaneous membrane curvature, or addition of macromolecules or proteins into the membrane. 

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