Glass ideal

Store a glass electrode in aqueous solution to prevent dehydration of the glass. Ideally, Do not leave a glass electrode out of water the solution should be similar to that inside the reference compartment of the electrode. If the (or in a nonaqueous solvent) any longer than... 

There is no need to demonstrate repeatedly that microorganisms are unable to penetrate the molecular structure of glass. Ideally, ampoules present a hermetic environment totally enclosed within glass. A completely broken ampoule is obvious, and more than likely its contents have spilled or leaked out. The subtlety of inadequate ampoules is in tiny cracks through which microorganisms may penetrate and, more likely, unsatisfactory flame sealing of the ampoule. 

The heat loss might be substantially reduced using storm windows of two or more panes of glass. Ideally, we would hope that this loss would now be governed by heat conduction across the gap between the panes. In fact, free convection stirs the air in this gap, so that the heat loss is much greater than that due to conduction. Still, this new resistance to heat transfer sharply reduces heat loss. 

The MCB tubes suit ideally into a concept of using glass capillary X-ray light guides to increase radiation intensity at the measurement spot. 

The basic observation is that a thin plate, such as a microscope cover glass or piece of platinum foil, will support a meniscus whose weight both as measured statically or by detachment is given very accurately by the ideal equation (assuming zero contact angle) ... 

Ideal connections for chlorine are ground glass joints, but previously used and well-fitting rubber stoppers give satisfactory results. Owing to the poisonous character of chlorine, the apparatus should be fitted up in the fume cupboard. 

Fig. 3. The tetrahedra in the schematics represent four oxygens clustered around a siUcon. Schematic representation of (a) an ideal crystalline stmcture (Si—O—Si bond angles = 180°) (b) a simple glass (Si—O—Si bond angles = 144° according to Fig. 2) and (c) the addition of a modifier, in this case one molecule of Na20, causes the breaking of one Si—O—Si bond to form two Si—ONa linkages.

The iatroduction of a plasticizer, which is a molecule of lower molecular weight than the resia, has the abiUty to impart a greater free volume per volume of material because there is an iucrease iu the proportion of end groups and the plasticizer has a glass-transition temperature, T, lower than that of the resia itself A detailed mathematical treatment (2) of this phenomenon can be carried out to explain the success of some plasticizers and the failure of others. Clearly, the use of a given plasticizer iu a certain appHcation is a compromise between the above ideas and physical properties such as volatiUty, compatibihty, high and low temperature performance, viscosity, etc. This choice is appHcation dependent, ie, there is no ideal plasticizer for every appHcation. 

In the float-glass process, adopted by all leading plate-glass manufacturers, the molten glass is allowed to float and soHdify on the surface of a pool of molten tin which provides an ideally flat surface. The endless glass ribbon has a surface so smooth that cosdy grinding and polishing are unnecessary. 

Containers. The ideal container for zone melting should not contaminate the melt nor be damaged by the melt or subsequent contraction of the sohd. For organic materials, borosiUcate glasses are especially suitable, although metals and fluorocarbon and other polymers have also been successfliUy employed. 

Conversion of GS to (GSi)r wiU be carried out for two of the four cases of Table 5-10. Case 1 is an idealization of a metal-heating slab furnace or glass furnace, with its plane sink Ai combining with refractory surface to complete the enclosure. With insertion into Eq. (5-173) of GSi, GS, and S Si after converting each to its gray plus clear form, one obtains... 

Let us now see whether materials really show this strength. The bar-chart (Fig. 9.2) shows values of Oy/E for materials. The heavy broken line at the top is drawn at the level it/E = 1/15. Glasses, and some ceramics, lie close to this line - they exhibit their ideal strength, and we could not expect them to be stronger than this. Most polymers, too, lie near the line - although they have low yield strengths, these are low because the moduli are low. 

The SFA, originally developed by Tabor and Winterton [56], and later modified by Israelachvili and coworkers [57,58], is ideally suited for measuring molecular level adhesion and deformations. The SFA, shown schematically in Fig. 8i,ii, has been used extensively to measure forces between a variety of surfaces. The SFA combines a Hookian mechanism for measuring force with an interferometer to measure the distance between surfaces. The experimental surfaces are in the form of thin transparent films, and are mounted on cylindrical glass lenses in the SFA using an appropriate adhesive. SFA has been traditionally employed to measure forces between modified mica surfaces. (For a summary of these measurements, see refs. [59,60].) In recent years, several researchers have developed techniques to measure forces between glassy and semicrystalline polymer films, [61-63] silica [64], and silver surfaees [65,66]. The details on the SFA experimental procedure, and the summary of the SFA measurements may be obtained elsewhere (see refs. [57,58], for example.). 

Assuming that the glass electrode shows an ideal hydrogen electrode response, the emf of the cell still depends on the magnitude of the liquid junction potential j and the activity coefficients y of the ionic species ... 

Ideally, the walls should be of brick or concrete with an insulated roof. Large areas of glass should be avoided. It is desirable that all routine maintenance and operating functions can be carried out without having to open doorways. Openings and access to the boilerhouse should be away from sensitive areas. Free areas for air for both combustion and ventilation should be through acoustic louver... 

Ideally the product is a fine-grained ceramic containing interlocking crystals with sizes ranging from less than 10 nm in transparent glass-ceramics to several micrometres, with a residual, usually small, glass content. The behaviour of the material is largely determined by the choice of the cry-... 

While glass can provide many of the desirable features of an ideal inert material, fabrication difficulties prevent its use for large-diameter chemical process equipment, and mechanical considerations would in any case make it necessary to treat any such equipment with great care. 

---