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Large meshed membranes

Close meshed membrane electrode membrane electrode with large-meshed membrane. The small pores of its membrane allow diffusion of ions and molecules up to a certain size. Its potential is equal to the -> Donnan potential. [Pg.421]

Large meshed membranes. Rapid mixing of different electrolyte solutions is delayed and a diffusion potential arises due to the different diffusion coefficients of different ions (see also Chap. IIL3, Eq. IIL3.33). [Pg.230]

The gas dispersion tube technique is much easier to assemble and use than the dialysis membrane/wire mesh basket assembly, but it gives similar release profiles for 5-FU from EHCF or copolymers of EHCF with either HA or HHA. The gas dispersion tube method only requires 0.1 gram of material for an accurate kinetic profile of these prodrugs. The small gas dispersion tubes are useful for studies involving powders, but pellets would not fit into these tubes. The large size gas dispersion tubes or the wire basket technique could be used for powders or pellets, and can accommodate larger sample sizes. In summary the gas dispersion tube technique is reproducible, easy to assemble, easy to use, can distinguish polymers with different release rates, and the results can be correlated with our earlier studies. [Pg.124]

US Patent 6,183,542 was issued in 2001 for a palladium membrane process. This process provides an apparatus that can handle high flow rates of gas, per unit area of membrane, while using a minimal amount of hydrogen-permeable material. This is accomplished by using stainless steel mesh elements to reinforce the thin-walled, palladium or palladium alloy membranes. This process also provides the ability to withstand large pressure gradients in opposite directions and thus will make it easier to clean membranes that have been clogged with contaminants. [Pg.135]

Disc Filters Traditional types of large disc filter holders, if used at all for production purposes, are usually about 300 nun in diameter. The direction of fluid flow is from above the filter to below. The membrane is sandwiched between metal inlet and outlet plates equipped with the sanitary connections necessary to operate the filter. Because of the fragility of disc-type membranes, there must always be a support plate directly beneath the membrane. Support plates must be porous, often photoetched, chemically inert, and have minimal effects on flow rate. This often means an uneasy compronuse. Prevention of flow restriction requires extensive void space this acts against the plate s mechanical strength. Usually there is also a loose mesh drain plate beneath the support plate and resting on the outlet plate (Fig. 2). When serially stacked disc filters are used, each membrane requires its own support plate but there will only be one drain plate. [Pg.161]

It is often found that the sintered metal and porous ceramic supports that have been used for many academic membrane studies are very expensive, sometimes even exceeding the cost of the palladium alloy membrane by several fold. This situation cannot be accepted for commercial membrane modules, especially when a large membrane area of up to several hundred to several thousand square meters is required. Some of the least expensive membrane supports include tension springs for tubular membranes and woven wire mesh for planar membranes, but even these supports can be costly, and further development of exceptionally low cost membrane supports is needed. [Pg.149]

Just as we looked at the string as a chain of masses and springs (Figure 4.1), we could model a plate or membrane as a mesh of masses and springs as shown in Figure 12.1. The mathematical setup and equations for this physical system are not simple, and of course the computation of the whole mesh can become quite expensive, especially for fine sampling and/or large structures. [Pg.131]


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