Porous materials glasses

The tubular positive plate uses rigid, porous fiber glass tubes covered with a perforated plastic foil as the active material retainer (Fig. 2). Dry lead oxide, PbO, and red lead, Pb O, are typically shaken into the tubes which are threaded over the grid spines. The open end is then sealed by a polyethylene bar. Patents describe a procedure for making a type of tube for the tubular positive plate (90) and a method for filling tubular plates of lead—acid batteries (91). Tubular positive plates are pickled by soaking in a sulfate solution and are then cured. Some proceed directiy to formation and do not requite the curing procedure. 

Punshon-Explosive. Patented in 1870 consisted of NC soaked for 12 hrs in a sugar soln, and an oxidizer, such as a nitrate. Another expl, patented by the same inventor in 1875, was a 70% Dynamite contg either peat or toasted peas as absorbants, to which pulverized NC could be added. The third expl patented by Punshon (1880) consisted of nitric and picric acids absorbed on a porous material such as asbestos, and loaded into cartridges which were painted with a mixt of Na silicate and powdered glass Punshon was also the inventor of Qxonite and Victorite (qv)... 

The separator is frequently a sintered glass frit, but it may also be any of a wide range of inert, porous materials such as celloton, vycor or porvic or an ion exchange membrane. A number of stable ion exchange membranes suitable for use in aqueous and non-aqueous solvents have become available in recent years. 

Efflorescence. The solvent properties of water also causes efflorescence, a phenomenon whereby soluble or slightly soluble substances migrate from the interior of porous solids to the surface, where they precipitate. Efflorescence is an important factor in the decay and disintegration of many rocks, and of human-made porous materials such as ceramics, and even of some types of glass. On archaeological objects, efflorescence generally occurs mostly as a white, powdery, but sometimes consolidated accretion on the surface of the objects. Calcite, a form of calcium carbonate, is one of the most common substances to effloresce on archaeological ceramics. 

Silica sol-gel glasses are porous materials, which means some kind of solid material that has holes in it. These holes are also called pores. To call a material a porous material, there is usually some kind of implicit assumption of homogenization and length scale. The holes must be smaller enough, compared to the typical size of the piece of material that is considered, so that it is reasonable to consider the material as a mixture of solid framework and pores28. 

The open ends of the salt bridge are plugged with a porous material, such as glass wool, to stop the electrolyte from leaking out quickly. The plugs allow ion migration to maintain electrical neutrality. 

In both types of liquid-membrane ISEs, the membrane acts as an inunis-cible phase boundary between the aqueous and non-aqueous solutions inside the ISE (see the schematic diagram presented in Figure 3.13). In order to minimize mixing, the liquid membrane is held in place by an inert, porous material such as a rigid glass frit or a flexible synthetic polymer - the choice will depend on the manufacturer rather than on experimental considerations. 

In an early attempt to remove mists from a gas stream, by using a fluidized bed as a kind of filfer (Meissner and Mickley, 1949), if was found that the operation worked well if the bed particles had a porous structure, and that when non-porous particles were used fluidization ceased (i.e. the bed quenched) at very low moisture contents. This view is supported in work on the effect of bed moisture on the fluidization characteristics of fine powders (D Amore et al., 1979) in which if was shown that porous materials can tolerate considerably more liquid than non-porous particles (such as glass ballotini, sand and limestone) before what these workers call bed compaction occurs. Smith and... 

Porous materials and membranes used as filters have a number of small, often tortuous, pores. This type of filter includes sintered glass filters, organic... 

Porous vycor glass Surface-bound, octahedrally coordinated Fe3+ species obtained in the photolysis of Fe(CO)5 physisorbed onto the glass Magnetically ordered materials were obtained which exhibited magnetic hyperfine fields of 370 and 425 kG 798... 

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