The theoretical expression for the suction of water in wood given in the previous report is checked on samples of three representative kinds and the suction mechanism in each case is discussed. For the whole duration of two hour suction, the expression is applicable to only a few samples, but excepting the irregularity at the beginning of suction process, it is approximately valid to a good number of samples. Effect of pits just above and nearest to the base seems to be the main cause of the irregularity.
Pieces of commercial oxygen-free copper wire of 1 mm in diameter are cold-rolled to various degrees from 56% to 91% and annealed at a constant rising rate of 100°/hr from a room temperature to 400°C. The rigidity is measured by means of the torsion pendulum. The results which are given in graphs show that: (1) The rigidity of specimens of low rolling reduction decreases gradually up to a certain temperature indicating that it is chiefly the recovery that occurs in this temperature range. But as the temperatnre rises higher, the rigidity undergoes a rapid increase which shows that the recrystallization has set in. The temperature at which this increase becomes noticeable is lower for specimens of higher rolling reduction. (2) In specimens of the rolling reduction higher than 78%, the decrease in rigidity is no longer detectable probably because the recrystallization begins earlier overlapping the recovery. (3) There is a marked difference in the aspects the rigidity changes by temperature for specimens of high and low rolling reductions.
Several air-lock methods have hitherto been devised for vacuum apparatus such as, electron microscope and electron diffraction camera with the intention of saving the time of evacuation and also minimizing the contamination in changing specimens or dry plates-Yet, either the troublesome manipulation of pre-evacuation or the smallness of room for accommodating needed accessory or the risk of contamination of specimen by grease caused inconvenience. The new method is comprised in that two cylindrical rods of equal dia-meters, one with a projecting center piece at one end holding the specimen and the other with a cylindrical hole drilled axially to cover the projection, make one complete cylindrical rod when the two are joined together. The two rods are placed opposing with each other through Wilson seals on the walls of the apparatus so that, by joining the rods, the joint can be pushed in and out of the apparatus without disturbing the vacuum enabling the specimen to be changed when the joint is outside. A specimen holder for electron diffrac-tion camera is made on this principle with which diffraction patterns are obtained by both transmission and reflection with ease and the specimen can be changed without difficulty.
Transmission of force in solids exerted by explosion within the solid and the resulting fracture are studied. Test blocks are made of cement mortar and 3_??_100 grams of PETN are exploded in a hole prepared in the center of the block. Strain waves thereby produced are measured by eight electric wire strain gauges which are insulated and sandwitched between small pieces of cement mortar with Araldite as adhesive and buried at the time of making the block. Pulsating changes of voltage in these gauges are amplified and photographed using eight cathode-ray oscilloscopes. Proceeding and reflecting strain waves of the frequencies as high as 10KC are thus recorded and the shape, velocity and damping of the waves are obtained confirming the applicability of dynamic theory of elasticity to fracture problems of brittle materials.
In order to study the adhesiveness of Kovar (54% Fe, 29% Ni, 17% Co, γ-phase at room temperature) to glass for making aiγ-tight joint, structure and surface oxidation products of the alloy are investigated by electron and X-ray diffraction methods and optical micro-scopy. As is well known, γ-phase (f.c.c., a0=3.54 Å) of Kovar is easily transformed to α-phase (b.c.c., a0=2.84 Å) by cold works such as mechanical polishing and rolling. It is found that a cold-rolled specimen, which is composed of γ- and α-phases, produces electron-diffraction patterns of only γ-phase when polished electrolytically, indicating that α-phase dissolves out selectively. By such procedures surfaces varying in amounts of α-and γ-phases are prepared and their surface oxidation products are examined. The surface composed of γ-phase produces spinel type oxide and that of α-phase produces hematite type oxide below 500°C. At higher temperatures (above 600°C) both kinds of surfaces produce spinel type oxide. As it has been mentioned, the existence of spinel type oxide favours the metal to glass adhesion. But it is not the necessary condition since, even under the condition to produce hematite type oxide, fairly good joints are obtained.
Considering soil particles as perfect spheres, soil moisture index is calculated which involves the radius of the particle and helps us understand the summarized relation between soil moisture, capillary height, water vapor pressure, and relative humidity in soil pores. Below-the limiting value of.the index, it can be seen that the capillary water practically ceases to move and the water vapor movement dominates, and that the relative humidity in soil pores begins to drop from 100 per cent.
In continuation of the frictional measurement described in the previous paper revealing -plastic micro-flow at the point contact before breaking, the effect of time scale of external-driving force is studied. A test rod is axially driven, shearing the contact part of specimen to be studied. The -rod is screwed into another light-alloy rod which is attached to a moving coil shell of an out-put dynamic speaker of transless type. (Fig. 2) The moving coil has an impedance of 400Ω forming an arm of an impedance bridge. (Fig. 1) The impedance bridge is adjusted so as to balance when the rod is perfectly clamped by frictional force. While increasing the driving force, when it attains the value of static frictional force of the specimen, the rod starts to oscillate in small amplitudes around the neutral point bringing the impedance bridge out of balance. Static frictional force (SFF) is obtained by observing the starting driving force. The rod can be made to stop oscillating by decreasing the driving force, representing, thereby, another jumping point which, corresponds to “dynamic frictional force” (DFF). DFF is essentially similar to SFF, while its value takes rather the magnitude of kinetic frictional force (KFF) owing to the very short period of repose. Measurements are made with some metals and high polymeric solids at different fre-quencies. In general, SFF and DFF are found frequency-dependent. For most polymer samples, the curves for them fall rapidly down at 200_??_600 cycles/sec. with increasing frequency. This dispersion in regard to frequency seems to be due to some rheological properties of the contact parts of samples.
When a small amount of Sr89 is doped to the oxide cathode, some depression of electron emission is observed when Co60 is plated to Ni sleere of core metal or to the anode, the emission more or less increases. The former (in the case of Sr89) agrees with Johnson's result and the latter is contrary to Defiesse's result.