Lead silica

Channel electron multipliers (CEM) are fabricated from lead-silica glass (Fig. 1.32) and can have curved or straight forms. In a channel electron multiplier, when the charged particles (positive or negative) hit the surface of the electrode, electrons are produced from the surface which then generate the current. 

Janes, Neumann and Sethna ° reviewed the general subject of solid lubricant composites in polymers and metals. They pointed out that the reduction in mechanical properties with higher concentrations of solid lubricant can be offset by the use of fibre reinforcement. Glass fibre is probably the most commonly used reinforcing fibre, with carbon fibre as a second choice. Metal and ceramic fibres have been used experimentally to reinforce polymers, but have not apparently been used commercially. To some extent powders such as bronze, lead, silica, alumina, titanium oxide or calcium carbonate can be used to improve compressive modulus, hardness and wear rate. 

Valeurs limites reglementaire - mandatory Sestablished for asbestos, benzene, venylchloride, lead, silica, wood dust and inhalable and respirable dust). 

The refining process typically begins with crushing of the ores, then concentration by froth-flotation, which yields material that is typically 15 - 20% Cu. The main impurity in these concentrates is iron however, nickel, gold, and silver are often present, along with traces of zinc, selenium, arsenic, antimony, tellurium, cobalt, tin, and lead. Silica (sand) is... 

Baryta white. See Barium sulfate Baryta yellow. See Barium chromate Barytes. See Barium sulfate Basic bismuth chloride. See Bismuth oxychloride Basic copper sulfate. See Cupric sulfate anhydrous Basic lead silica chromate. See Lead silicochromate Basic lead white silicate. See Lead silicate Basic zinc chromate. See Zinc chromate Battery acid. See Sulfuric acid... 

Synonyms Basic lead silica chromate Lead silicochromate, basic Definition Orange pigment consisting of lead chromate-coated silica Pmperties Orange pigment dens. 4.0 kg/l Toxicology TLV 0.15 (Pb)mg/m of air... 

It is qualitatively known (6) that increased silica contents in the feed materials could increase the production of neutral leach residue. However, now it possible for Ruhr-Zink to quantitatively examine not only the influence of silica on the production of ZIC but also the synergistic influence of alumina, iron, lead, silica, and zinc on the production of ZIC. 

Basic green 4. See Malachite green oxalate Basic green 1, sulfate (1 1). See Basic green 1, Basic lead chromate. See Lead chromate oxide Basic lead silica chromate. See Lead silicochromate... 

Synonyms Basic lead silica chromate Lead silicochromate, basic... 

The gold tubular glass samples tended to be covered with flaky black, presumably corrosion-related material that was mostly removable during sonication. Data for the eleven cleaned gold glass samples are presented in Table IX. The primary features of these data are the very low levels of K and Na, and the low levels of Ca and Cl. These features imply that the gold beads are lead-silica glasses. 

In using the table for pore size calculations, it is necessary to read off the values of the uptake from the experimental isotherm for the values of p/p° corresponding to the different r values given in the table. Unfortunately, these values of relative pressure do not correspond to division marks on the scale of abscissae, so that care is needed if inaccuracy is to be avoided. This difficulty can be circumvented by basing the standard table on even intervals of relative pressure rather than of r but this then leads to uneven spacings of r . Table 3.6 illustrates the application of the standard table to a specific example—the desorption branch of the silica isotherm already referred to. The resultant distribution curve appears as Curve C in Fig. 3.18. 

The hydrophobic character exhibited by dehydroxylated silica is not shared by the metal oxides on which detailed adsorption studies have been made, in particular the oxides of Al, Cr, Fe, Mg, Ti and Zn. With these oxides, the progressive removal of chemisorbed water leads to an increase, rather than a decrease, in the affinity for water. In recent years much attention has been devoted, notably by use of spectroscopic and adsorption techniques, to the elucidation of the mechanism of the physisorption and chemisorption of water by those oxides the following brief account brings out some of the salient features. 

Vitreous silica is susceptible to attack by alkaline solutions, especially at higher concentrations and temperatures. For 5% NaOH at 95°C, although craving may be evident, surface corrosion is only 10 p.m after 24 h (87). For 45 wt % NaOH at 200°C, dissolution proceeds at 0.54 mm /h (88). The corrosion rates in other alkaline solutions are Hsted in Table 3. Alkaline-earth ions inhibit alkaline solution attack on vitreous siUca. Their presence leads to the formation of hydrated metal siUcate films which protect the glass surface (90). 

Cellulose acetate Silica gel Scoured wool Sawdust Rayon waste Fluorspar Tapioca Breakfast food Asbestos fiber Cotton linters Rayon staple Starch Aluminum hydrate Kaolin Cryolite Lead arsenate Cornstarch Cellulose acetate Dye intermediates Calcium carbonate White lead Lithopone Titanium dioxide Magnesium carbonate Aluminum stearate Zinc stearate Lithopone Zinc yellow Calcium carbonate Magnesium carbonate Soap flakes Soda ash Cornstarch Synthetic rubber... 

The complexes on surface of chelate-functionalized silica often include ligands available in solution in the coordination sphere. Use of a chromophore reagent as a ligand leads to the formation of colored mixed ligand complexes (MLC). The phenomena can be used as a basis for developing test-systems for visual determination of microquantities of inorganic cations in water. 

Effective metal ion adsorbent has been prepai ed by the immobilization of propylthioethyleamine ligand onto the surface of silica gel (SN-SiO,).The effectiveness of this material to bind metal ions has been attributed to the complexation chemistry between the ligand and the metal. We are investigating properties of propylthioethyleamine grafted on the surface of silica and possibility of application of the obtained surface for preconcentration of heavy metals such as zinc, lead, cadmium, copper, etc. from water solutions. 

The express method of phenolic compounds determination was designed. It is based on heterogeneous azo-coupling reaction of phenols, which different extracts of fresh raw material contain, with aryldiazonium salts grafted on the silica surface. We can carry out phenols analysis on-site, as formation of immobilized azocompounds leads to a drastic change in the sorbent s color. Thus, we pui pose a new method, that allows to indicate herb phenols in aqueous and non-aqueous medias and to compare it with a well-known Folin-Ciocalteau method. 

In the sintering of such materials as silicon nindde, a silica-rich liquid phase is formed which remains in the sintered body as an intra-granular glass, but this phase, while leading to consolidation, can also lead to a deterioration in the high-temperature mechanical properties. 

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