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Crushing of powdery materials (stone ware and hard chalk) was accomplished with a drop hammer. The impact resistance force P produced was measured with a wire-strain-gage dynamometer and a Brown-tube oscilloscope, and the total deformation of the packed sample, with a photoelectric tube or a depth gage. From these results were obtained P-δ curve for various samples relative to loading conditions. (Fig. 12-15).Graphical integration of P-δ curve gave the actual work Ur and further the relation between Ur and A or η and A, where A is the gross energy input and η is the efficiency of the energy. (η=Ur/ A×100%) (Fig. 16.-Fig. 19, Fig. 20 is a schematic representation). These data are classified into two groups. In the first group, the gross energy input A, and in the second group, the drop weight or the drop height, is a regulating factor. The former case is likely to happen when the pile height is small, when the penetration of stress is perfect throughout the sample and when solidification of powder occurs. And the latter, which is the most general of all the crushing conditions, often happens when the pile height is big and the penetration of the stress is not uniform.Lastly, by comparing the actual work Ur with the resultant crushed product D, the authors obtained an almost linear relations between them.

Creep rupture tests of unplasticized PVC were carried out by having dipped the specimens in various chemical reagents. The authors called these tests as “Wet rupture tests.”Formerly, they studied the creep strength under air atmosphere (dry test) for unplasticized PVC which was previously dipped in chemical reagents at various temperatures, and confirmed that the creep strength was not markedly affected by the kind of chemical reagents used.But, the creep mechanism of these wet tests is very different from that in dry tests, for the action of chemical agents cooperated with the working stress.They classified the chemical reagents into three groups having regard to the behaviors in creep rupture and summarized in Table 1.

高分子材料への環境薬液の浸入を調べるために, 浸漬によって樹脂が自然に着色する場合 (PVC+conc. HCl) と指示薬によって酸の浸入部分を着色した場合 (ABS+30%HNO3) の着色深さを顕微鏡で測定した。浸漬試験の重量変化から得られた拡散係数, 飽和濃度を使って求めた着色限界点の環境薬液濃度の最低値は数mg/cm3-resinであった。またPVCを60℃のconc. HClに浸漬した場合について. 着色深さ測定値から求めた薬液浸入の拡散係数は2.6×10-6cm2/hrであった。

Crushing was accomplished by dropping a steel ball on a plunger resting on cubic or powdery samples (Hakun stoneware) in a steel mortar, and it was sometimes accomplished by driving a ball mill at normal speed. The experimental results were as follows:The relation between pass-through of the crushed products and no. of blows is shown in Figs. 2 & 3. In these figures, pass-through increment Dz-Dz-1 shows Max. value when Z=Zm, and it falls in value, down nearly to zero, when. From these experimental results, the authors have assumed that the relation between net work input to crushing and no. of blows is given by Eqs (3) & (4).The authors have round close similarity between these equations and the corresponding experimental results. The relation between residue or surface increment and the net work input to crushing is represented by Eqs.(5) & (6). Eqs (3) & (4) are applicable to not only cubic samples but also powdery samples (of same size) crushed in a mortar or in a ball mill driven at normal speed. In Fig.9, the authors show how to select the most effective no. of blows Zopt.By studying Figs.2, 4 etc., the authors have found that the curve is concave upward for smaller values of no. of blows Z, and convex upward for larger values, but nearly linear for medium values. When the work input to crushing in the Rittinger's, Kick's and Tanaka's law is assumed to be proportional to no. of blows, Eqs.(4) & (6) correspond to the Kick's law for the 1st stage of crushing, to the Rittinger's law for the 2nd stage and to the Tanaka's law for the 3rd stage.