Laboratory behavior, standard operating

No serious attempt has yet been made to standardize filtration tests and to categorize filtration behavior in generally accepted terms. A possibly useful measure of filterability, however, has been proposed by Purchas (1977 1981). The time in minutes required to form a cake 1 cm thick when the cell is operated with a differential of 500Torr (0.67 bar) is called the Standard Cake Formation Time (SCFT), tF. The pressure of 500Torr is selected because it is obtained easily with common laboratory equipment. The procedure suggested is to make a series of tests at several cake thicknesses and to obtain the SCFT by interpolation, rather than to interrupt a single test to make observations of cake thickness. A direct relation exists, of course, between the SCFT and resistivity a some examples are... 

The results of the evaluation showed the RIs to vary only slightly with the different operator, the different instrument of the same manufacturer with the same column in one or several laboratories, column individuals of the same manufacturer, solvents (diethyl ether, acetone, and ethyl acetate), and use of a multistep temperature program. There were no significant differences in the reproducibility of RIs determined using different index standard series. M-standards are relatively nonpolar and differ little in their behavior from C-standards on a nonpolar SE-54 phase. When the number of index standard components was reduced, the RI values... 

Another approach to in-service testing is to monitor the behavior of the materials in a fleet of captive vehicles. This enables better control and recording of the exposure and driving conditions. The use of fleet vehicles also makes it possible to test coupons representing a wider range of materials. Coupons mounted on pickup trucks operated in Montreal, Quebec, and St. John s, Newfoundland for up to five years served as the real-world standard of performance in a laboratory test development by SAE/ACAP and The American Iron and Steel Institute s Corrosion Task Force. The materials being used in these tests are described in Table 1 and results after five years of testing at these sites are shown in Fig. 3 [64],... 

---