New types of electro-dynamic vibration tables of vertical and horizontal directions for whole body at sitting and standing postures were devised. The tables could gener-ate various kinds of output wave forms (sinusoidal, random and shock vibration) with large amplitude and wide frequency range. The levels of threshold and equal sensation of whole body for both vibrations were measured at sitting and standing in erect and relaxed states on various amplitudes in the range from 0.5 to 300 c/s and up to 60 dB (vibration acceleration level at 20 c/s). The curves of threshold for vertical and horizontal vibrations consist of 5 or 4 straight lines withbending points respectively, and each slope of these lines had physical meaning of jerk, acceleration, velocity and displacement. In addition, there is a difference of vibration acceleration level between both thresholds by about 10 dB. The contours of equal sensations for both vibrations above 5 c/s are composed of three lines with the slope of acceleration, velocity and displacement bending at 5 c/s and 60 c/s. Below 5 c/s, those of equal sensation for horizontal vibration show considerably lower values than those for vertical one.
The sensation of horizontal vibration was equated to that of vertical vibration ofthe same frequency at 5, 10, 20, 30, 60, 100, 200 and 300 c/s. The sensation of verticalvibration above 5 c/s was found to be stronger than that of horizontal vibration by 10dB for sitting and by 13 dB for standing. Then, the horizontal vibrations from 0.5 to 200 c/s were equated in sensation withthe vertical vibration of 20 c/s at 30 dB (vibration acceleration level (VAL)) forsitting alone. The contours obtained in this experiment and the curves of the equalsensation for horizontal vibration on whole body are quite similar with each otherexcept that VAL at the standard frequency (20 c/s) of the latter is larger by 10 dBthan that of the former
The levels of threshold and equal sensation on hand for vertical and horizontalvibrations (3-300 c/s) were determined by the same method in the previous reports andtheir characteristics did not differ between both vibrations. The equal sensation curvesof hand above 10 c/s showed good agreement with those of whole body. Then, the sensation of hand for horizontal vibration was equated to that of verti-cal one and it was observed that the sensation for both vibrations was equal at thesame vibration acceleration level and frequency.
Population threshold for olfactory perception have been obtained with eight kinds of primary odour substances to develop the method of field study. Triangle method and serial method have been used for the measurement and the latter has been proved to be suitable for the present purpose. Reliability of population threshold values for olfactory perception and effect of volume of sample solution on the values have been examined. New device has been developed to illustrate the olfactory function of subject.
In order to clarify the state of depressed hematopoiesis of bone marrow due to ben-zene poisoning, the metabolic features of the nucleic acids, which closely relate to the cell proliferation, were studied in the rabbits poisoned with benzene. The bone mar-row tissue turned fatty and showed a significant decrease of the cell number after the treatment with benzene. The amounts of the nucleic acids per unit weight of the tis-sues, especially DNA of the treated animals decreased. Both the ratio of s-RNA to DNA and r-RNA to DNA increased to about twice the normal levels. The synthetic rates of s-RNA, r-RNA and DNA, which were estimated by the rate of uptake of 32p, apparently rose in the treated animals, while those of the liver were not affected. These results suggest that accelerated syntheses of the nucleic acids occur compen- satively in the bone marrow cells by the treatment with benzene.
An attempt to simplify procedure for analysis of polynuclear hydrocarbons in par-ticulates in town air was carried out. Vacuum sublimation method was employed to extract organic materials from the particulates instead of the method with a Soxhlet apparatus. The sublimate was dissolved in small amount of benzene and the solution was submitted to direct gas chromatographic analysis by utilizing a flame ionization detector or an electron capture detector. It was proved that further purification of the sublimate by partition was unnecessary in this method. Seven polynuclear hy-drocarbons including benzo(a)pyrene were determined on the collected particulatesfrom the air by this method.
This paper deals with a new routine microanalytical method for the determination of 2-naphthylamine in commercial 1-naphthylamine. The analytical method consists of a) isolation of 2-naphthylamine by thin layer chromatography and b) spectrofluoro-metrical determination. By this method, 2-naphthylamine in 4 or more samples was determined with a high accuracy in about 3 hours. Commercial 1-naphthylamine for industrial use contained about 4% 2-naphthylamine and the practical grade reagent for laboratory use contained about 3% 2-naphthylamine.
Two standard aerosols consisting of solid spherical particles and of liquid ones were prepared from sodium chloride and dioctyl phthalate. For both cases, aerosols having a narrow size distribution from 0.2 to 0.8 μ in the average particle diameter were prepared. The retention efficiency for the air-filter was studied by determining the concentration of an aerosol before and after passage through the 20 cm2 testing filter. The efficiency, in general, increased with increasing particle size. Somedis-cussion is made on the fluctuation in the efficiency of the air-filter made from fiber.
With various types of the vibration isolation materials with cellular holes, the dy-namic complex elasticity, which is important in the field of the vibration problems but is rather difficult to obtain, was measured. While, the static chracteristics, hardness and static elasticity and viscosity, were also tested with the same materials, which can be obtained easily. Then, the interrelations of the both values were investigated and linear relations were observed between the static and dynamic values. Therefore, in design of the hand protectors or the handle covers for prevention of the harmful vib-ration, the dynamic complex elasticity of isolating materials can be estimated from their static values. It was also found that effect of the sample's shape on the static elasticity did not exist in these materials with celluar holes.