Quartz, from melts

The practice of heating and forming glass-like figures from melted silica (sand) was known at least three or four thousand years ago. In the eighteenth century early chemists were aware of some kind of link between sand (silica) and quartz but were unaware that a new, unidentified element was involved. 

Quartz j I Quartz glass melted from Brasilian SiOa 1000-1100 (1011) 7.0-7.2 6.96 7 119-1072... 

According to Westbrook and Stover[(1967)—quartz glass melted from a crystalline quartz shows hardness Hv at 293 K close to the hardness of crystalline quartz. 

Theoretical refining time concerns the removal of the last bubbles formed at the disappearing quartz grain-melt interface it is calculated from eqn. (36) for // 0 (initial condition ... 

Nearly all ICP torches consist of three concentric quartz tubes surrounded by a coil carrying radiofrequency (r.f.) power, referred to as the load coil. The middle tube carries the Ar that forms the plasma while Ar flow in the inner tube serves as a carrier for sample introduction. This punches a hole in the center of the plasma, creating a toroidal plasma with a central axial channel that acts as the atomization-ionization cell. The plasma forms under the load coil, past the exit of the inner and middle tubes. The outer tube extends beyond the coil and carries a tangential flow of Ar that serves as a coolant layer to prevent the torch from melting in addition to centering the plasma. 

Axial gradient chlorination is performed in a titanium camera with two windows from melted quartz for UV-radiation. The device scheme is shown in Figure 23. A sealed film advance mechanism (1) equipped with a block (6) (reducer-motor with a cam mechanism) provides for PP film (2) delivery to the chlorination chamber (3) for the reaction governed by the relation x = f(f). Emitters (4, 5) located inside the chamber (3) allow the process to proceed at increased temperature. 

We developed a sensor for determination of content of phosphorars in metallurgical melts. In quality of ion conductor used orthophosphate of calcium which pressed in tablets 010 mm. Tablets (mass 1-2 g) annealed at a temperature 400°C during 7-10 h. Tablets melts then in a quartz tube and placed the alloy of iron containing 1 mass % P. Control of sensor lead on Fe - P melts. Information on activities (effective concentration) of phosphorars in Fe - P melts was received. It is set that the isotherm of activity of phosphorars shows negative deviations from the Raouls law. Comparison them with reliable literary inforiuation showed that they agree between itself. Thus, reliable data on activities (effective concentration) of phosphorars in metallic melts it is possible to received by created electrochemical sensor for express determination. 

In a crystal-pulling procedure using a tri-arc furnace (Fig. 2), a resistor box, a d.c. power supply (300 A, 80/40 V) and a set of water-cooled power cables are used to bring power and water to the electrodes. The upper part of the furnace is equipped with three equally spaced copper cathodes, to which are fixed W-Rh electrodes. The upper part (cathode) is separated from the lower part (anode) by a transparent quartz glass tube. In the bottom of the furnace there is a tapered opening for a water-cooled copper hearth containing the boride melt. All parts of the furnace are also water... 

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