AN INTERPRETATION OF GLASS CHEMISTRY IN TERMS OF THE
... conditions such as the 0 2 partial pressure of the atmosphere in which the glass was melted. A more satisfactory type of probe ion is one which responds in a direct and, more importantly, a gradual manner to changes in glass basicity. Recently, it has become apparent that probe ions which respond in ...
... conditions such as the 0 2 partial pressure of the atmosphere in which the glass was melted. A more satisfactory type of probe ion is one which responds in a direct and, more importantly, a gradual manner to changes in glass basicity. Recently, it has become apparent that probe ions which respond in ...
Y04505127134
... dispersion in the profiles of dielectric constant and loss tangent would be resulting in because of space charge polarization effect at the electrode-electrolyte interface and it is also noticed that a.c increases in accordance with frequency change. Keywords: Optical glasses and Dielectric propert ...
... dispersion in the profiles of dielectric constant and loss tangent would be resulting in because of space charge polarization effect at the electrode-electrolyte interface and it is also noticed that a.c increases in accordance with frequency change. Keywords: Optical glasses and Dielectric propert ...
Lead resistance in micro-organisms
... Lead (Pb) is an element present in the environment that negatively affects all living organisms. To diminish its high toxicity, micro-organisms have developed several mechanisms that allow them to survive exposure to Pb(II). The main mechanisms of lead resistance involve adsorption by extracellular ...
... Lead (Pb) is an element present in the environment that negatively affects all living organisms. To diminish its high toxicity, micro-organisms have developed several mechanisms that allow them to survive exposure to Pb(II). The main mechanisms of lead resistance involve adsorption by extracellular ...
Redox behavior of platinum-group metals in nuclear glass
... observed as grains or needles dispersed in the glass [8]. The equilibrium constants of the oxidation reaction RuO2 Ru + O2 are given in Table I for a mixture of pure metal and oxide. Two models were considered in this study for the relation between the Ru0/Ru4+ redox molar ratio and the oxygen fug ...
... observed as grains or needles dispersed in the glass [8]. The equilibrium constants of the oxidation reaction RuO2 Ru + O2 are given in Table I for a mixture of pure metal and oxide. Two models were considered in this study for the relation between the Ru0/Ru4+ redox molar ratio and the oxygen fug ...
Lead glass
Lead glass is a variety of glass in which lead replaces the calcium content of a typical potash glass. Lead glass contains typically 18–40 weight% lead(II) oxide (PbO), while modern lead crystal, historically also known as flint glass due to the original silica source, contains a minimum of 24% PbO. Lead glass is desirable owing to its decorative properties.Originally discovered by Englishman George Ravenscroft in 1674, the technique of adding lead oxide (in quantities of between 10 and 30%) improved the appearance of the glass and made it easier to melt using sea-coal as a furnace fuel. This technique also increased ""working period"" making the glass easier to manipulate.The term lead crystal is, by technicality, not an accurate term to describe lead glass, as glass, an amorphous solid, lacks a crystalline structure. The use of the term lead crystal remains popular for historical and commercial reasons. It is retained from the Venetian word cristallo to describe the rock crystal imitated by Murano glassmakers. This naming convention has been maintained to the present day to describe decorative hollow-ware.Lead crystal glassware was formerly used to store and serve drinks, but due to the potential health risks of lead, this is rare nowadays. One alternative material is crystal glass, in which barium oxide, zinc oxide, or potassium oxide are employed instead of lead oxide. Lead-free crystal has a similar refractive index to lead crystal, but it is lighter and it has less dispersive power.In the European Union, labeling of ""crystal"" products is regulated by Council Directive 69/493/EEC, which defines four categories, depending on the chemical composition and properties of the material. Only glass products containing at least 24% of lead oxide may be referred to as ""lead crystal"". Products with less lead oxide, or glass products with other metal oxides used in place of lead oxide, must be labeled ""crystallin"" or ""crystal glass"".