Resistive Glass

AU ground glass joints should be constructed of a high resistance glass, such as Pyrex. The most common form is shown in Fig. II, 55, 1, and this is the type largely encountered in practice. Fig. II, 55, 2 is... 

Temperature, °C Soft glass Heat-resistant glass... 

Bulk separations Bulk sweeteners Bulk viscosity Bulletproof vests Bullet-resistant glass Bullets... 

Bullet-resistant glass is contmcted of many layers of glass and aircraft-type PVB depending on the level of resistance desired. Typical products are 38—50 mm thick and weigh 90-130 kg/m. ... 

Shipment and Storage. Sulfur dichloride, if kept dry, is noncorrosive at ambient temperatures, thus carbon steel and Hon can be used Hi the constmction of tanks, piping, and dmms. However, when water or humidity is present, materials resistant to hydrochloric acid must be used, eg, glass-lined pipe. Teflon, titanium, HasteUoy C, or possibly a chemically resistant, glass-reiaforced polyester. Threaded pipe joHits should be assembled with Teflon tape. Hoses should be constmcted with a Teflon inner lining with the outer tube constmcted of Neoprene or braided 316 stainless steel protected by an adequate thickness of Teflon. Sulfur dichloride should be stored away from heat and away from dHect rays of the sum. Toluene and sulfur dichloride react exothermically when catalyzed by Hon or ferric chloride. Safety precautions should be foUowed when such a mixture is present (165). 

Materials that come in contact with wet halogens must be corrosion-resistant. Glass, ceramics, tantalum, and fiuoropolymers are suitable materials. Granite has been used in steaming-out towers. 

Infusion Boiling water (150 250 ml) is poured over the prescribed amount of drug in a heat-resistant glass or porcelain vessel, which is then covered if necessary, the contents are stirred occasionally. If no other indication is given, the contents arc strained after 5 -10 min. This method can be used for most leaves, flowers, and herbs and also for many correspondingly comminuted barks and roots. 

Thin, nonwoven fabric composed of randomly oriented and adhered glass fibers of a chemically resistant glass mixture. 

Heat resistant glasses (e.g. Pyrex), glass wool, fibre glass 26% (60%)... 

Felsen, m. rock cliff, -ader,/. dike, -alaun, m. rock alum, -boden, m. rock soil, -ge-birge, n. Rocky Mountains, -glas, n, ( rock glass") a resistant glass for bomb and combustion tubes, -glimmer, m. mica, felsenhart, a. hard as rock, rocky. 

The tubing glass is suitable for general laboratory use and chemical apparatus construction, though neutral or hard borosilicate are preferred for more severe conditions, these representing the most resistant glasses available in bulk form. 

The high-purity water thus produced typically has a conductance of about 0.5 x 10-6fi-1cm-1 (0.5juScm-1) and is suitable for use under the most stringent requirements. It will meet the purity required for trace-element determinations and for operations such as ion chromatography. It must however be borne in mind that such water can readily become contaminated from the vessels in which it is stored, and also by exposure to the atmosphere. For the determination of organic compounds the water should be stored in containers made of resistant glass (e.g. Pyrex), or ideally of fused silica, whereas for inorganic determinations the water is best stored in containers made from polythene or from polypropylene. 

This operation is the separation of the precipitate from the mother liquor, the object being to get the precipitate and the filtering medium quantitatively free from the solution. The media employed for filtration are (1) filter paper (2) porous fritted plates of resistance glass, e.g. Pyrex (sintered-glass filtering crucibles), of silica (Vitreosil filtering crucibles), or of porcelain (porcelain filtering crucibles) see Section 3.24. 

U.S. Pharmacopoeia XVIII, Light transmission Chemical resistance-glass... 

Phoenix, also, is a borosilicate glass made by the British Heat Resisting Glass Co. The linear expansion coefficient (50-450°Q is 3-24 X 10" . Tubing and rod are supplied in a wide range of sizes. The tubing is made with either standard wall or heavy wall. 

Byrex Chemical Resistance Glass has a Young s modulus of 6-1 x 10 dynes/cm , a modulus of rigidity of 2-5 x 10 dynes/cm and a Poisson s ratio of 0-22. Similar values are found for other glasses. 

Apart from the necessity of excluding interferences from any diffusion potential, normal potentiometry requires accurate determination of the emf, i.e., without any perceptible drawing off of current from the cell therefore, usually one uses the so-called Poggendorff method for exact compensation measurement the later application of high-resistance glass and other membrane electrodes has led to the modern commercial high-impedance pH and PI meters with high amplification in order to detect the emf null point in the balanced system. 

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