Degassing, coating

A powder coating is the result of the application of a powder binder system, which generally consists of a resin, a crosslinker, flow additives, degassing agents, pigments or dyes, charge control agents, etc. Such a binder system is ap-pHed to the substrate as a fine, extruded powder (Fig. 20, step A), then melted at... 

Benzophenone (2.0 g, 11 mmol) and sodium beads (0.6 g, 26 mmol) are loaded into a 100-mL Schlenk flask equipped with a Teflon coated stir bar in a glove box. Under an N2 atmosphere degassed THF, 60 mL, is added, and the solution is vigorously stirred for at least 1 h. The resulting solution of sodium benzophenone is deep blue or purple, and it must be protected from air by an N2 atmosphere. 

In the glove box, 8.1 g (34.0 mmol) of freshly amalgamated uranium turnings (see Section 55.A) are placed in an oven-dried, 250-mL, one-neck Schlenk reaction vessel, along with a 1-in. Teflon-coated magnetic stirring bar, and 200 mL of distilled, degassed pyridine. The reaction vessel is removed from... 

The a-diketone 1 (ca. 2.0 mmol) in dichloromethane (5 mL) was added to silica gel (5 g) in a 100-mL round-bottomed flask. The mixture was sonicated for 5 min after which the solvent was evaporated under reduced pressure. The coated silica gel, divided into six nearly equal portions, was then placed in Pyrex tubes (18 Xl80 mm). In the experiments under oxygen-free conditions the tubes were degassed by three freeze-pump-thaw cycles and sealed. The tubes were rotated and irradiated for 48 h with a 100-W high-pressure mercury lamp. The irradiated silica gel was collected. Acetone (20 mL) was added to the silica gel to extract... 

Ip is degassed and then distilled into a previously evacuated 23 cm long quartz cell with wedged (1.5°) anti-reflection coated windows epoxied on the ends. The cell is mounted in the laser cavity on X-Y-Z translation stages, and the I2 is frozen into the sidearm by dipping it in+a cold bath. The dye lasing threshold is measured, and the Ar laser is then set to the desired power. For one set of experiments, threshold pump power is near ( 11%) 550 mW, while for a second set the threshold is near 790 mW. 

Africa, and Canada. In the Siberian samples, three components have been identified with different Ar isotope compositions. Atmospheric blank is a small component present in most analyses. The major component is characterized by high °Ar/ Ar (>11,000) and constant OArVCl (527 22 X 10 ), Br/Cl = 1.7 X 10 and I/Cl = 22 X 10 , indicative of a mantle fluid phase. This component is also characteristic of African and Canadian fibrous diamonds and leads to estimated mantle halogen abundances in the fluid source region of 3 ppm Cl, 11 ppb Br, and 0.4 ppb I (Burgess et al, 2002). As with noble gas systematics, these data are very comparable to estimates for MORB-source mantle and implies that the mantle is >90% degassed of its halogens. A third Ar component in coated diamonds appears to be the result of decay since the time of kimberlite eruption. 

---