Double crucible method

The double crucible method and the rod-in-tube method are used primarily for higher-loss fibers made... 

Process. Single filaments of clad fiber may be made by redraw of rod in tubing or, alternatively, by a double-crucible method, which is essentially a Vello-type delivery system, where a second glass, rather than air, is delivered through the center of the bell. A version of the latter method is illustrated in Fig. 6.43. 

The double crucible method to draw optical fibres uses two crucibles positioned into each other. The inner crucible contains the glass material from which the core is drawn whereas the outer crucible holds the melt for the... 

Double-cell system, in soil and ground water treatment, 25 835 Double crucible technique, 11 135-136 Double-deck kiln, 15 530 Double-drum dryers, 9 134 Double-drum separator, 15 446 Double-effect distillation, 10 153 Double end point titration method,... 

In the Taiqing methods, the crucible is typically formed by two superposed vessels made of red clay (chishi zhi) and joined by their mouths. Owing to this feature, the texts often mention a double crucible [liangfu) or an upper and lower earthenware crucible shangxia tufu). According to the... 

Tantalum Pentafluoride, TaFs, is the only known fluoride of tantalum, and has been successfully isolated by methods that avoid hydrolysis (1) Tantalum and fluorine are brought into reaction exactly as in the preparation of niobium pentafluoride.1 (2) Tantalum penta-chloride is treated in the cold with dry hydrofluoric add the hydrochloric acid liberated and excess of hydrofluoric add are evaporated oft, and the resulting tantalum pentafluoride is purified by redistillation in a platinum crucible between 300° and 400° C.2 (3) The double barium tantalum fluoride, 3BaF2.2TaF5, is very strongly heated in a platinum tube, one end of which is kept cold. ... 

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