Glass formulations

Natron and ash of seaweeds provided the sodium which served as the flux in all glasses till the Medieval period. Wood ashes then came into use, which changed the glass formulation to such a degree that potassium salts became the principal fluxing alkaUes. 

Initially, at least, methanol vehicles should be capable of operating on either M85, gasoline, or any mixture of the two. These vehicles are caHed flexible fueled (EEV) or variable fueled vehicles (VEV). It is expected that methanol could be sold in existing service stations out of tanks constmcted of methanol-tolerant material such as carbon steel or certain fiber glass formulations. EventuaHy, if enough EEV/VEVs are sold and methanol becomes widely avaHable, dedicated vehicles would likely be buHt and sold. Methanol has been used for years as a racing fuel. 

The properties of high quaUty vitreous sihca that determine its uses iaclude high chemical resistance, low coefficient of thermal expansion (5.5 X 10 /° C), high thermal shock resistance, high electrical resistivity, and high optical transmission, especially ia the ultraviolet. Bulk vitreous sihca is difficult to work because of the absence of network-modifyiag ions present ia common glass formulations. An extensive review of the properties and stmcture of vitreous sihca is available (72). 

If a product is sensitive to particular ions such as barium or calcium, glass formulations are available where these are excluded. 

Example Optimization of an Eleven Component Glass Formulation. Piepel (6) discussed the generation and analysis of a mixture design consisting of eleven oxides used to prepare glasses for waste vitrification. Although many responses must be considered for the end use of this composition, the intent of Piepel s study was to minimize the response of leachability subject to the compositional constraints of ... 

Oriented polymers are less susceptible to ESC than randomly oriented polymers since the load is spread more evenly between the parallel chains. In glass reinforced composites, ESC of the glass itself can take place in acids, although recent glass formulations have proved more resistant. 

Component Optimized Glass Form with Additives Nonadditive Glass Formulation... 

Petitiean, V., Fillet, C., Boen, R., Veyer, C. Flament, T. 2002. Development of vitrification process and glass formulation for nuclear waste conditioning. In Waste Management 02 Conference. Laser Options, Inc., Tucson, CD-ROM. 

Intramolecular hydrogen-transfer to an excited imine is responsible for the photochromism of derivatives of salicylaldehyde (o-hydroxybenzaldehyde) irradiation converts the colourless or yellow imine into a much more intensely coloured photoproduct 15.9), but removal of the light source allows rapid reversal of the process. Reactions of this kind form the basis of some organic photochromic glass formulations exposure to increasingly bright light alters the proportion of the isomers in favour of the dark-coloured photoproduct. 

Lithium fluoride. CAS 7789-24-4. LiF, mp 848 C, soluble in HyO tslighl I Used in enamel and glass formulations as a component of w elding and brazing fluxes in the eiectrowinning of aluminum and as an ingredient of molten salts. 

The quantitative compositional surface analysis of the untreated glass fibers using XPS was complicated by the presence of carbon [5]. Nevertheless, the plot in Fig. 1 reveals that the boron concentration on the untreated fiber surfaces did, in fact, increase in proportion to its addition to the glass formulation, while the... 

Use of the potential of a galvanic cell to measure the concentration of an electroactive species developed later than a number of other electrochemical methods. In part this was because a rational relation between the electrode potential and the concentration of an electroactive species required the development of thermodynamics, and in particular its application to electrochemical phenomena. The work of J. Willard Gibbs1 in the 1870s provided the foundation for the Nemst equation.2 The latter provides a quantitative relationship between potential and the ratio of concentrations for a redox couple [ox l[red ), and is the basis for potentiometry and potentiometric titrations.3 The utility of potentiometric measurements for the characterization of ionic solutions was established with the invention of the glass electrode in 1909 for a selective potentiometric response to hydronium ion concentrations.4 Another milestone in the development of potentiometric measurements was the introduction of the hydrogen electrode for the measurement of hydronium ion concentrations 5 one of many important contributions by Professor Joel Hildebrand. Subsequent development of special glass formulations has made possible electrodes that are selective to different monovalent cations.6"8 The idea is so attractive that intense effort has led to the development of electrodes that are selective for many cations and anions, as well as several gas- and bioselective electrodes.9 The use of these electrodes and the potentiometric measurement of pH continue to be among the most important applications of electrochemistry. 

Parenterally formulated biopharmaceuticals are typically packaged in glass containers with rubber/synthetic elastomeric closures. Pharmaceutical glass is composed primarily of silicon dioxide tetrahedron which is modified with oxides such as sodium, potassium, calcium, magnesium, aluminum, boron, and iron [45],The USP classifies glass formulations as follows ... 

Amber glass containers can be used for light-sensitive SVIs. The amber color is produced by the addition of iron and manganese oxides to the glass formulation. Oxide leachates can occur and catalyze oxidation reactions. 

In our experiments, the glass components, as either oxides or carbonates, are dry-mixed and heated at 850°C for 1 hr to remove water and carbon dioxide. The mixture is then melted for 1 hr, placed in a 400°G furnace for 1 hr, and then removed to cool to ambient temperature. A typical product is shown in Figure 5. In our initial studies, 14 glass formulations based on these models and the seven formulations shown in Table VIII made acceptable glasses. 

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