Casting procedure

The diffusion coefficients of potassium and sodium chlorides in the membrane we have found to be independent of solution concentration within experimental error. The value of sodium chloride agrees well with those found by others bearing in mind the differences in the polymer and in the membrane casting procedures (5,13). 

The above set of rules - though accurately descriptive of earlier casting procedures - has led to serious misconceptions pertaining to the formation of anisotropic membranes, and therefore, misconceptions in the formulation of new polymeric casting solutions. It is evident that the polymer solution concentration progressively increases at the surface layer during the evaporation period, and... 

The casting procedure consisted of drawing an aqueous solution of PVA to a thin layer, and after an evaporation period, immersing in the complexing bath. The complexing bath used in our study was basically a saturated CuSO solution, with or without a series of possible additives. After a period of equilibration of over 24 hours, the membranes were dried and subjected to dry heat treatment,in order to stabilize the asymmetric structure obtained. The preparation conditions of several membranes prepared by this method are shown in Table V. 

In principle, it is also possible to Improve and modify the selectivity properties of these membranes by using other methods for crosslinking them, such as formalization or reaction with tolylene dllsocyanate, mentioned earlier, or by selecting other complexlng agents for the casting procedure. 

The molten expl is usually poured thru a funnel-former. This tool is specially designed to furnish the desired surface contour upon removal and to hold a sufficient reservoir of molten expl to replenish the shrinking, cooling mass beneath it.. A thin film of silicone grease is applied sometimes to the former to aid in its release when the expl has solidified Effect of Casting Procedure On Charge Characteristics. 

In a cast charge (unlike in a pressed charge), both density and pore or cavity size are determined by the casting procedure. Both of these factors must be considered by the designer in terms of their effects upon safety, reliability, and performance... 

Routine casting procedures for TNT work well with a TATB/TNT formulation, 1) of Table 4. The higher thermal conductivity of a TATB/TNT/A1 formulation, 2) , requires addnl side insulation of the molds and a crack inhibitor such as anthracene to produce intact charges free of fine cracks (Ref 28)... 

Experiments indicate that the critical strain-to-failure is also affected by the average molecular weight and by material processing history. McGrath40 reported strain-to-break of a non-crystalline ionomer (a poly(arylene-ether) random copolymer, biphenyl sulfone in H form, or bi-phenyl sulfone in H form (BPSH)) is proportional to the length of the chain. We found in our laboratory that the casting procedure also affects the strain-to-break of the solution-cast ionomer film. As shown in Fig. 19, a Nation film cast at near room... 

Figure 12. X-ray radiograph of section of the wall of the Hu shown in Figure 11. From the evidence seen in this radiograph—square and rectangular supports behind each figure, the white spots on or near each rod (solder), and dark areas (voids in metal) around each figure—the casting procedure described in the text can be deduced. Exposure 275 kV, 4 mA, lead screens.

The radiographic evidence strongly supports a lost-wax casting procedure and does not indicate a sand piece-mold process as demonstrated by the following observations. The iron armature is not an iron wire, as used in modem processes, but is an irregular band, approximately 12 mm wide and 2 mm thick (Figure 17). Similar armatures and also iron chaplets have been observed in many bronzes manufactured in... 

Fused cast basalt is cast in many shapes. Standard flat surfaces can be lined with square or rectangular standard flat tiles. Cylinders for pipe systems are made in static or centrifugal casting procedures. Wall thickness ranges from 21 mm for centrifugal spun cast cylinders to 30 mm thickness for the statically mold cast cylinders and tiles. Thicker liners can also be made. 

---