Liquid-impregnation

These capacitors differ from standard p.f, improvement capacitors, as they are designed to withstand higher test voltages and have a low internal inductance. They should preferably be non-inflammable, synthetic liquid impregnated and provided with a built-in discharge resistance. For specifications refer to VDE 0675 and VDE 0560 III,... 

Liquid/Impregnated Solid Contact Inflammation of tissue around eyes Reddening of skin Ulceration of skin into watery boils Blistering of throat and lungs Dry land drowning Destruction of white blood cells Bone marrow destruction Damage to immune system Often leads to death... 

In both situations the interaction of the medium inside the pore with the pore wall (1) is increased (2) or changed which affect the transport and separation properties (surface diffusion, multilayer adsorption) and/or help overcome equilibrium constraints in membrane reactors. Membrane modifications can be performed by depositing material in the internal pore structure from liquids (impregnation, adsorption) or gases. Several modification possibilities are schematically shown in Figure 2.3. Some results obtained by Burggraaf, Keizer and coworkers are summarized in Table 2.7. Composite structures on a scale of 1-5 nm were obtained. 

Nondispersive solvent extraction is a novel configuration of the conventional solvent extraction process. The term nondispersive solvent extraction arises from the fact that instead of producing a drop dispersion of one phase in the other, the phases are contacted using porous membrane modules. The module membrane separates two of the immiscible phases, one of which impregnates the membrane, thus bringing the liquid-liquid interface to one side of the membrane. This process differs from the supported liquid membrane in that the liquid impregnating the membrane is also the bulk phase at one side of the porous membrane, thus reducing the number of liquid-liquid interfaces between the bulk phases to just one. 

The mobile phase in vapour phase chromatography is a gas (e.g. hydrogen, helium, nitrogen or argon) and the stationary phase is a non-volatile liquid impregnated onto a porous material. The mixture to be purified is injected into a heated inlet whereby it is vaporised and taken into the column by the carrier gas. It is separated into its components by partition between the liquid on the porous support and the gas. For this reason vapour-phase chromatography is sometimes referred to as gas-liquid chromatography. 

Two cases can be distinguished, depending on whether the pore space of the support contains only ambient air at the start or whether it is already filled by the solvent from the impregnation solution (usually water) or by another liquid. Impregnation is said to be capillary in the former case and diffusional in the latter. 

Carbon-Fiber-Reinforced Carbon Composites Fabricated by Liquid Impregnation... 

Carbon/carbon composites fabricated by multiple cycles of liquid impregnation and recarbonization are a typical example of modern petroleum derived carbons. In the 1975 ACS Symposium on Petroleum Derived Carbons (JL), papers were presented on carbon/carbon composite materials formed by pyrolytic infiltration processes (2 ) or by liquid impregnation with petroleum pitch (3,4), on fabrication processes for high-modulus carbon fibers based on polyacrylonitrile (PAN) or pitch precursors ( 5 ), and on the use of carbon materials for thermostructural (6 ) as well as biomedical applications (1 ) ... 

Figure 11, Schematic mechanisms of pore filling and pore blocking by liquid impregnation and by chemical vapor deposition (26).

Vendange, V., Colomban, R, and Larche, F., Pore size and liquid impregnation of microporous aluminosilicate gels and glasses, Microporous Mater, 5, 389, 1996. 

Multidimensional BN fiber infiltrated (matrix) composites are analogous to carbon-carbon composites and overcome the brittleness and low to moderate thermal shock resistance of hot-pressed BN. With the availability of BN fibers (see 17.3.5.4), a weave of three or more dimensions is possible. Chemical vapor deposition may produce a turbostatic BN matrix that is sensitive to H2O, while liquid impregnation requires multiple reimpregnation cycles h One scheme is to impregnate a BN woven fiber preform with H3BO3, dry, sinter in NH3, and hot-press. 

Mahale, A.D. Prud Homme, R.K. Rebenfeld, L. Quantitative measurement of voids formed during liquid impregnation of nonwoven multifilament glass networks using an optical visualization technique. Polym. Eng. Sci. 1992, 32 (5), 319-326. 

Liquid impregnated (or immobilized) in the pores of a thin microporous sohd support is defined as a supported liquid membrane (SLM or ILM). The SLM may be fabricated in different geometries. Flat sheet SLM is useful for research, but the surface area to volume ratio is too low for industrial applications. Spiral-wound and hoUow-fiber SLMs have much higher surface areas of the LM modules (103 and 104 m /m, respectively [23]). The main problem of SLM technology is the stability the chemical stability of the carrier, the mechanical stability of porous support, etc. 

The formulations of the liquids impregnated in the wipes and the liquids supplied in bottles are similar. Typically, foam suppressors such as silicones are added to minimize foaming during the cleaning so as not to leave consumers with the impression that rinsing may be needed. 

The formulations of both the liquid impregnated on the wipes and the liquid supplied in a bottle are similar. They are more similar to glass cleaning formulas in their surfactant concentrations, although they tend to have lower solvent content than do glass cleaners. They are likely to contain suds suppressors (such as silicones) because excess foam would leave the impression that the surface needed to be rinsed. 

The methods mentioned above for the preparation of ordered graphitic mesoporous carbon involve the use of liquid impregnation strategies (repeated infiltration and polymerisation) followed by the carbonisation... 

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