Industrial Health
Online ISSN : 1880-8026
Print ISSN : 0019-8366
ISSN-L : 0019-8366
Volume 15 , Issue 1-2
Showing 1-10 articles out of 10 articles from the selected issue
  • Hiroshi KANDA, Daizo GOTO, Yukio TANABE
    1977 Volume 15 Issue 1-2 Pages 1-12
    Published: 1977
    Released: April 17, 2008
    JOURNALS FREE ACCESS
    An experiment on board an actual vessel was carried out with cadets, who were boarding a training ship for the very first time, as the subjects of the ex-periment. The pattern of motion sickness incidence was one in which the incidence increased sharply during the periods the cadets were on watch, and sharply de-creased during their free, off-watch periods. The vertical acceleration (rms) in-cluding heaving, rolling and pitching of the ship was taken as the magnitude of the periodic motion. The motion sickness incidence was divided into three Grades, I (slight), II (moderate), and III (serious). Percentages of incidences in Grade I or above, Grade II or above and Grade III were obtained, and the linear relationship with the acceleration was found. Grade I or above would consist of the total of Grade I, II, and III (I+II+III), Grade II or above would consist of the total of Grade II and III (II+III). In those cases where there was not much fluctuation in the acceleration, the incidence ratio attained its maximum 2 to 3 hr after exposure. It was also observed that acclimatization effects to periodic motion made them-selves apparent by a reduction in the proportion of incidence ratio of motion sickness to acceleration as the number of aggregate days of the cruise increased. Hiroshi, KANDA;Daizo, GOTO;Yukio, TANABE
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  • PART 1. EXPERIMENTAL STUDY OF THE EFFECT OF VERTICAL VIBRATION ON HUMAN SLEEP
    Kazuhide YAMAZAKI
    1977 Volume 15 Issue 1-2 Pages 13-21
    Published: 1977
    Released: April 17, 2008
    JOURNALS FREE ACCESS
    There have been many reports of the effects of whole-body vibration on phy-siological function of human body, but there have been no experimental studies on the effect on sleep. Subjects were exposed to very low level of vibration (vertical direction) and the effects on sleep were studied. The subjects were 4 healthy male students and a vibration exposure was done to the subject sleeping on a vibration table once per 30 min for 30 sec. Vibration levels measured on bedclothes were 60, 65, 69, 74, 79 dBVL. Effects of vibration on sleep were investigated by comparing sleep stages before and after the vibration exposure.
    If the maximum permissible level of vibration on sleep is determined on the basis of the result of this experiment, 65 dBVL will be considered to be appropriate as vibration level not affecting to sleep in the Stage 2 so remarkably. If the maximum permissible level of vibration which does not affect to sleep is necessary to be determined, 60 dBVL will be appropriate.
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  • Yoshiharu YONEKAWA
    1977 Volume 15 Issue 1-2 Pages 23-32
    Published: 1977
    Released: April 17, 2008
    JOURNALS FREE ACCESS
    Sensation of an intermittent vibration such as bullet train vibrations was equ-alized to the sensation of a continuous random vibration which possessed frequency characteristics of 6 dB/oct between 8 and 80 Hz. The values of the intermittent vibration read by the vibration level meter standardized in this country (physical quantity) corresponded to the equal sensation value of the random vibration (sensa-tion quantity). This type of random vibration was able to use as the model of the bullet train vibrations. It was noticed in the experiment of sensation comparison that the longer the length of rest time between the sample train vibration and the compared random vibration was, the lower the equal sensation values became.
    Then, emotion caused by this continuous model random vibration was rated in an evaluation scale in 5 steps (scarcely unpleasant, slightly unpleasant and so on). The experiment was carried out on a vibration table and on 10 male subjects. The first step "scarcely unpleasant" corresponded to 65 dBVL (vibration level, rms acceleration levels weighted by frequency characteristic simulated for human vibra-tion response, in dB) the second step "slightly unpleasant" to 80 dBVL and the third step "unpleasant" to 90 dBVL for vertical vibration. For horizontal vibration, the third step corresponded to 92 dBVL. Thus, the emotional response could be estimated from the observed values obtained from the bullet trains.
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  • Yoshiharu YONEKAWA
    1977 Volume 15 Issue 1-2 Pages 33-45
    Published: 1977
    Released: April 17, 2008
    JOURNALS FREE ACCESS
    For establishment of evaluation method on one shot shock motions generated jumping down in prefabricated private houses, feeling of shock on jumpimg was equalized to sensation of one shot model pulse on the vibration table. The model. pulse signals were made by a C-R discharge circuit starting with a monostable multivibrator and its wave shapes were varied by changing time constants of the C-R circuit. It was found that one shot of the model shock with longer duration produced larger sensation than that with shorter duration. It was also noticed that the smaller level of one shot shock motion caused weaker sensation than the larger level of it.
    Then, the sensation of one shot of these model pulses was equalized to that of a sinusoidal vibration at 10 Hz. A relation between the level of the sinusoidal vibration (dBAL) and logarithmic value of the duration of pulses was derived through a parameter of amplitude of the pulses. Using this equation, the equal sensation level of sinusoidal vibration for actual pulses could be estimated, which. agreed with the values observed directly.
    One shot model shock of which durations were changed at 40, 60 and 100 ms and levels at 6 grades from 95 to 120 dBAL was rated on a psychological evalua tion scale in 5 steps. The sensation at the third step of "unpleasant" corresponded to 114 dBAL for one shot shock with the duration of 40 ms, to 116 dBAL for 60 ms and to 119 dBAL for 100ms.
    Thus, a clue of solution for an evaluation method for one shot pulse was pre-sented.
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  • PART 1. OBSERVATION OF ELECTROMYOGRAM
    Tadayoshi SAKURAI
    1977 Volume 15 Issue 1-2 Pages 47-58
    Published: 1977
    Released: April 17, 2008
    JOURNALS FREE ACCESS
    Electromyogram on the forearm flexor and extensor was observed with surface electrodes under conditions of experiments in which a subject was asked to grip a handle on a vibration table and was given vibration. In these experiments, factors concerning vibration exposure time, vibration amplitude, vibration frequency (30, 60, 125 and 250 Hz), gripping force, handle diameter and room temperature were examined by using the orthogonal array table in the experimental design method. It was found out that low frequency components of the electromyogram on the forearm flexor and the forearm extensor were significantly intensified with increase of the levels of vibration magnitude, gripping force, handle diameter and exposure time. Change of room temperature (22° or 10°C) did not affected the electromyogram.
    The relation between the increase of low frequency components of the electro-myogram on the forearm and sensation response for holding a weight was studied to establish the evaluation scale of the low frequency component. Using this scale, the emotional response to the vibration impressed during gripping of the handle was estimated and improvement of operating conditions of vibrating tools with regard to these factors was suggested on the basis of muscle fatigue.
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  • PART 2. OBSERVATION OF SKIN TEMPERATURE
    Tadayoshi SAKURAI
    1977 Volume 15 Issue 1-2 Pages 59-66
    Published: 1977
    Released: April 17, 2008
    JOURNALS FREE ACCESS
    Skin temperature at the third finger tip of left hand on the radial side was observed with a thermister. Vibration was given the left hand of a subject who gripped a handle set on a vibration table of electrodynamic type. The room tem-perature was varied at 22°C and 10°C.
    Effects of factors concerning the vibrations (magnitude, frequency, exposure time), gripping force and room temperatures on the skin temperature were studied by using the experimental design method. In the first experiment, for impressing large vibration magnitude over 50 g, recovery of the skin temperature after stop of the vibration was slow as compared with the small vibration amplitude. In the second experiment, the recovery of the skin temperature was clearly retarded in the low room temperature (10°C). This tendency especially was promoted on the longer vibration exposure time than the shorter one.
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  • Masana OGATA, Reiko SUGIHARA, Hiroko ASAHARA, Shohei KIRA
    1977 Volume 15 Issue 1-2 Pages 67-75
    Published: 1977
    Released: April 17, 2008
    JOURNALS FREE ACCESS
    A quantitative procedure is described for determining urinary glycine conjugates. The color development was recognized after addition of pyridine and benzenesul-fonyl chloride to glycine conjugates. The dried residue of ethyl acetate extract from urine was dissolved in pyridine and benzenesulfonyl chloride was added. After addition of chloroform to the mixture, the absorbance was determined at 420 nm (extracting method). In the improved procedure of direct colorimetric method, pyridine was added to urine and mixed; then benzenesulfonyl chloride was diluted with mixture of dimethylsulfoxide and ethanol, and absorbance was deter-mined at 430 nm (improved direct method).
    To separate each glycine conjugate, paper chromatographic procedure was car-ried out. Urine specimen each was directly developed on filter paper with butanol- acetic acid-water or isopropanol-ammonia-water. On the other hand, ethyl acetate extract from urine was developed with toluene-acetic acid-water. Comparing the spots with authentic sample spots, each location was determined by illuminating with ultraviolet light. Then, each spot was extracted with pyridine. Benzen-sulfonyl chloride was added to the extract; the absorbance was determined at 420 nm. Complete separation of urinary glycine conjugates could be done by two-way chromatography.
    The normal values of urinary glycine conjugates were also compared by ex-tracting method and improved direct method.
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  • Tsuguyoshi SUZUKI
    1977 Volume 15 Issue 1-2 Pages 77-85
    Published: 1977
    Released: April 17, 2008
    JOURNALS FREE ACCESS
    Urine and plasma mercury values in relation to hand tremor and proteinuria were studied for workers in three workshops of different types of mercury exposure. Proteinuria was transiently observed in workers of shorter length of mercury ex-posure, but the ephemerality of hand tremor was partial, i.e., different by types of exposure, and was observed in workers of longer length of exposure.
    No good correlations were observed between urine or plasma mercury values and these two symptoms, and relations of urine to plasma mercury values differed by the type of exposure and the uniformity in workers' composition in duration of exposure.
    The minimum urine or plasma mercury value and its variation due to the type of exposure were discussed at appearance or persistence of hand tremor and pro-teinuria.
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  • Toshio MATSUSHITA, Mitsuki YOSHIOKA, Yoshiki ARIMATSU, Shigeru NOMURA
    1977 Volume 15 Issue 1-2 Pages 87-94
    Published: 1977
    Released: April 17, 2008
    JOURNALS FREE ACCESS
    Cross sensitizations among dithiocarbamate fungicides were investigated using the guinea pig maximization test. Extreme potency of cross-reaction was noted among ethylene bis-dithiocarbamates, maneb, mancozeb and zineb. Such degree of potentialities, however, was not revealed in cases of dimethyldithiocarbamates, ferbam, thiram, ziram and dimethyldithiocarbamic acid sodium salt. Cross-contact allergy among other combinations of dithiocarbamates and their related compounds were tested and discussed.
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  • Reisuke SODA
    1977 Volume 15 Issue 1-2 Pages 95-108
    Published: 1977
    Released: April 17, 2008
    JOURNALS FREE ACCESS
    Volatility of mixture solution of organic solvents was studied by an infrared analysis of vapor concentration evaporated from the solution. The ratio of concen-trations of components was observed with various processes of evaporation. The ratio observed was different from that which was calculated by equilibrium of vapor and solution. When the evaporation was carried out at very low inner pressure of the system, the ratio was close to that of solution, while when vapor was slowly evaporated from the solution the ratio was interpreted by vapor pressure and diffu-sion rate. When the system was standing for a while, both the ratios approached to the value by equilibrium. Test samples were methanol-toluene and ethyl acetate-toluene mixtures. That trend was also observed by commercial adhesive but the difference in the ratio by the variation of evaporation process was far less than that observed with the test sample.
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