Upper loading point

Images of the sample pieces were taken before and after the test. Figure 7 displays failure plane location in each of the samples. In batch A, aU the samples collapsed between the upper two loading points. In batch B one specimen and in batch C almost three specimen failed out of the pure bending area. This can be dne to the reason that for weaker samples the uniformity of the load becomes more and more important in flexural tests. On the other side, for materials with low Weibull modulus it is normal to have a number of samples(around 10% of them) fracturing outside of the inner gage area. 

Because of the steep pitch required, slides are limited in application. They are most commonly used to bridge the gap between roller-conveyor systems on two floors, because the roller conveyor can take the container off the slide rapidly and ehminate or reduce the chance for collisions. Slides may also be used when containers can be chuted from an upper floor to a manually loaded carrier. The use of several rollers at the feed point is recommended for easy dehveiy to the sloping section. If the drop is short and containers light, a roller cleanout will prevent backup of containers on the slide. The slope of gravity slides is a function of container weight, size, and friction characteristics and should be selected with care to be sure that containers do not move either too swiftly or not at all. Slides usually use flat steel sheet. 

The standard ASTM PCE test is relative and used extensively only for alumina—silica refractories and raw materials (see Table 5). However, the upper service limit is generally several hundred degrees below the nominal PCE temperature because some load is generally applied to the refractory during service. In addition, chemical reactions may occur that alter the composition of the hot face and therefore the softening point. The relationship between PCE numbers and temperature is described in ASTM C24. 

Fig. 9.2. Constant-volume tensimeter. The sample tube (enlarged view, upper left) is loaded with solid in a dry box or by sublimation from the vacuum line. The lube is evacuated, sealed, weighed, then glassblown to the tensimeter. After evacuating and flame-drying the tensimeter, the mercury level is raised and the break-seal cracked. Since the mercury serves as the cutoff to the vacuum manifold, the sample is not exposed to grease, stopcocks, or joints. This design is desirable when very long equilibration times are necessary. The mercury level is adjusted at the volume-calibrated reference point, such as A on (he diagram, if it is important to know the gas volume in the apparatus.

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