Glass flow lines

Figure 7.2.2 Schematic diagram of the flow probe developed by Dorn and co-workers and used for the direct coupling of SFC to NMR (a) insulated glass transfer line (b) glass insert (c) Cu/constantin thermocouple (d) stainless steel equilibrium coil (e) brass shield (f) Helmholtz coil (g) ceramic flow cell (h) brass Swagelok fitting. Reprinted with permission from Allen, L. A., Glass, T. E. and Dorn, H. C., Anal. Chem., 60, 390-394 (1988). Copyright (1988) American Chemical Society...

However, the precise location of the decomposition and glass transition lines may depend upon pyrolysis conditions because kinetic factors such as gas flow rate, stirring conditions, heating rate, etc., all affect the relative extents to which evaporation and cracking reactions contribute to the change in composition. 

The heats of adsorption of the probe molecules were measured in a heat-flow microcalorimeter of the Tian-Calvet type from Setaram, linked to a glass volumetric line to permit the introduction of successive small doses of gases [6]. The equilibrium pressure relative to each adsorbed amount was measured by means of a differential pressure gauge (Datametrics). Successive doses were sent onto the sample until a final equilibrium pressure of 133 Pa was obtained. The adsorption temperature was maintained at 353 K in order to limit physisorption interactions between the probe molecules and the zeolites. All the samples were pretreated at 773 K under vacuum overnight prior to any calorimetric measurement. 

Figure 25.13 Flow lines in the ATR 10 mixing chamber and the visualization experiment conducted with a glass reactor for validation [40].

Twin-plate Process. A process for the simultaneous grinding and polishing of both faces of a continuously-produced ribbon of glass the complete flow-line is over 400m long. The process was introduced by Pilkington Bros. Ltd, England, in 1952. 

Figure 5.21. Intersecting flow lines observed in the plastically deformed region of glass beneath an indenter with (a) no effect on each other, (b) one line kinked, and (c) both lines kinked.

Equations (1.13), (1.14), and (6.9) give Hy — 4.5sufficiently close to phenomena associated with yield and flow are not apparent in macroscopic breaking tests of glass. Nevertheless clearly from the appearance of the area directly beneath an indenter the material can be made to flow as these stresses are reached and exceeded. The intersection of flow lines below the glass surface is the site of flaw generation leading to failure. 

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