When flowing granular mass is photographed with intermittent illumination, paths of granules appear as series of broken lines. By measuring both the intermittent time and the lengths of broken lines, the velocity of granules is determined. Method of photographing and results of measurement are described.
As a high voltage source of super-high voltage electron microscope, a belt generator was constructed which is smaller in size and lower in cost than a customary type of voltage source. With a little care in design and manipulation, the generator is found satisfactory in obtaining steady voltage and in arresting vibrations. During 30 second run of operation, the voltage fluc-tuation was kept below 0.03_??_0.05% at 300 kV which is steady enough to obtain micrographs of high resolution with compensated lens system for chromatic aberration. Detailed descriptions on the construction, performance and results of testing are given.
Imporvements were added to the experimental apparatus used before so as to take the simultaneous measurements of the horizontal and vertical components of the resistive force acting upon a wheel rolling on sand dried in natural state and also the depth of the sinking of the wheel in sand. The range of measurement was widened at the same time. By the use of this renewed apparatus, variations of the constants K and n of the empirical formula H=KVn, which relates the horizontal components H to the vertical components, V of the resistive force acting upon a disc-shaped wheel, were measured under different conditions in regard to the diameter and the thickness of the wheel and the packing state of the sand. The results obtained are applied to the study of the relationship between the traction resistance of a car and the position of its gravity center.
For 23 kinds of paper varying gloss (from completely matt to glossy enough to give mirror image), I-θ curves were obtained by means of the goniophotometer (Fig. 1), where I is the intensity of the reflected light and θ the rotating angle of the specimen. The curves are found to be represented by I=I2e-βθ for completely matt paper, I=I1e-αθ+I2e-βθ for glossy paper, I=I1e-αθ2+I2e-βθ for highly glossy paper, respectively. (I1+I2)/I2, (=GNF), shows an intimate correlation with the gloss grading of the papers as judged by a visual test. The contrast gloss and the Sheen gloss for the papers are compared with GNF.