Leave-behind mechanism

Figure 2. Schematic of lamella formation by the "leave-behind" mechanism. (Reproduced with permission from Ref. 40. Copyright I986 SPE-AIME.)...

Ransohoff and Radke found that for C <10 lamella generation occurred only by the leave-behind mechanism. The lamellae moderately increased the resistance to flow, raising it by about a factor of five (40). (Here p is the viscosity of the nonwetting phase, U is the total superficial velocity, R is the bead radius, K is the absolute permeability, k is the relative permeability, L is length, and Y is the interSacial tension.) The use of this definition of the capillary number, instead of the usual C = jU/y, with J the viscosity of the wetting phase, was justified in the heoretical analysis ( ). 

Figure 7. Schematic of leave-behind mechanism showing (a) gas invasion and (b) stable lens. (Reproduced with permission from reference 60. Copyright 1989 Society of Petroleum Engineers.)...

Lamella Leave-Behind A mechanism for foam lamella generation in porous media. When gas invades a liquid-saturated region of a porous medium, it may not displace all of the liquid, but rather leave behind liquid lamellae that will be oriented parallel to the direction of the flow. A foam generated entirely by the lamella leave-behind mechanism will be gas-continuous. See also Lamella Division, Snap-Off. 

If a particle A must know B s total information content before colliding, the collision process must be delayed until A has full access to that information. However, such a delay is consistent neither with classical nor quantum mechanics, Minsky instead suggests that the collision proceeds immediately, but with the particles both working with less than all the information that is classically required i.e, the incoming particles momenta are estimated. Outgoing momenta are determined via conventional classical rules, but, because of the estimation errors, each scattered particle leaves behind a receipt recording how much momentum was really taken away in the process. Receipts not only mark prospective event-locations at which future collisions might take place, but harbor information that can be used to estimate new real momenta. 

A significant amount of waste composites is generated each year and the need for a recycling method is becoming a necessity. Environmental Technical Services has developed, with the support of the University of Missouri-St.Louis, a method for recovering valuable constituents from composite materials. The process converts the polymer matrix to lower chain hydrocarbons and fuel gas leaving behind fibres. Mechanical tests of BMC panels, reinforced concrete and compression moulded panels made with recovered fibres were carried out. 10 refs. USA... 

In spectral sensitization, conduction electrons appear in the silver halide crystal when the dye absorbs radiation, just as when the silver halide absorbs radiation. According to the mechanism that has received the strongest support in recent years, an electron is transferred to the silver halide from the excited dye molecule, leaving behind an electron-deficient dye molecule (hole). This is analogous to the result of direct absorption of a photon by the silver halide, except that the hole remains in the dye, at least temporarily, instead of in the silver halide. 

Understanding the MnP and LiP mechanism is important not only from a fundamental point of view but also because delignification of wood chips leaves behind pulp, the fibrous polysaccharides (hemicellulose and cellulose) that... 

On the other hand, Schottky defects occur when ions of different charges leave their sites in the crystalline lattice leaving behind two vacancies. In the case of the Schottky [42] mechanism, the following equilibrium, described with the help of the Kroger-Vink notation, is expressed [43]... 

These results indicate that the naphthalene radical anion is not stable to the solvent tetrahydrofuran at room temperature on a time scale of 100 hours. Decomposition pathways are alkali metal dependent. Sodium and potassium naphthalene attack THF through a proton abstraction, cycloreversion mechanism, as previously described by Bates for the butyllithium/THF system (27). Lithium naphthalenide attacks the THF not only by the Bates mechanism but also by a nucleophilic ring opening, as is implicit in earlier high temperature work on lithium naphthalenide in THF (28) and in work on the attack of THF by tritylmagnesium bromide (29). The two smaller alkali metals, lithium and sodium, leave behind a... 

Although with the selective removal proecdurc the active component and the support are usually verv intimately mixed, it is difficult to control the porous structure and/or the mechanical strength ol the result ing eatalyst bodies Nonetheless the procedure is difficult to beat for the production ol highly loaded supports The most well known example of selective removal, the preparation of Raney metals, where alu minum is selectively removed, leaves behind almost exclusively the desired active metal... 

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