Generation mechanisms of the electric impulses in the underground chemical explosions are described in this paper. The electric impulses just after triggering were commonly observed in three explosion seismic experiments. The common characteristics of the impulses are as follows: 1) The duration time of the impulse train is always less than 10 ms and no impulse is detected after 10 ms. 2) The duration time of each impulse is approximately 1 ms, the time structure is quite different, and the occurrence is intermittent. 3) The electric charge generation process can be modeled by a vertical electric dipole. It is the first time to clearly show that the duration of the impulses is caused by the total length of the explosion. The characteristics can be explained by two closely coupled generation processes; chemical explosion and excitation of electric charges by a thermo- or mechano-electric process. The primary process is explained by means of the excitation of high-temperature and high-pressure with a explosion. The secondary process is interpreted as a theme- or mechano-electric conversion process excited either by thermal energy or by mechanical energy in surrounding media consisted of rock and water. Two thermo-electric and four mechano-electric conversion processes are discussed in terms of the time structure, the direction of expected electric dipoles, and the confinement in the vicinity of . It is concluded that the most probable source of the observed electric impulses is the fractoelectric effect.

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X線回折法を用いて, ダイナマイト中の硝酸アンモニウム量を簡単でかつ分離操作することなく定量した.本方法は, まず安全のためにジエチルエーテルで有機ニトロ化合物を除去した後, 乾燥した.ついで, 乾燥した試料をX線回折法で測定した.硝酸アンモニウムの定量は, 多変量解析法であるクラスター分析や主成分分析で計算した.計算値は理論値とよく一致した.

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In Japan, by all possible preventive steps, serious cases of paroxysms of angina pectoris due to nitroglycol poisoning has been almost disappeared. Therefore, it is difficult to draw an exact line whether many subjective symptoms and clinical abnormal findings, which have been thought to be not so characteristic at nitroglycol exposure, are connected with nitroglycol or not. To ascertain the actual conditions in a factory and the adrenocortical reserve functions of workers exposed to nitroglycol, some investigations were attempted. Results are as follows; 1) In the factory, concentration of nitroglycol in an extruding room has been notably decreased year after year, and at present it is less than 0.2 ppm, i.e. the MAC value in Japan. 2) Concentrations of NO₃ content in the blood of workers do not increase so apparently after work. 3) Subjective symptoms of workers, except for headache, are statistically not significant in comparison with those of other workers. 4) Clinical abnormal findings of workers are not significant in our investigated items compared with other workers. 5) Adrenocortical reserve functions in workers, which were examined by a reaction to ACTH injection, were apparently decreased. Changes in eosinophil counts on workers were notably different from those of office workers; namely, in cases where no drug had been injected, eosinophils increased in about a half of the workers after four hours work. 6) But, there are no relation between adrenocortical reserve functions and other subjective symptoms or clinical findings. From these facts, the conclusions may be drawn as follows: 1) Nitroglycol poisoning in an investigated factory has passed a crisis apparently, but it seems to be not so hopeful that they are in a position, immune to moderate nitroglycol poisoning. 2) In order to make an earlier diagnosis of nitroglycol poisoning significant to prevent serious poisonings, an attempt of testing adrenocortical reserve functions on workers exposed to this chemical seems to be valuable.

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To examine pituitary-adrenocortical functions of workers exposed to nitroglycol some investigations were made.
1. Evaluating by the reaction to 25 units of ACTH-Z (ACTH-Gel), the decrease of the adrenocortical functions of workers were noted, in spite of rather healthful environmental conditions of the investigated shops. The decrease of eosinophil counts induced by ACTH injection was remarkably small.
2. In case of 0.25 mg synthetic ACTH administration similar data were obtained con- cerning the decrease of circulating eosinophil counts.
3. The increase of the circulating concentration of free plasma 11-hydroxycorticosteroids, which was induced by 0.25 mg synthetic ACTH administration, was obviously small in case of workers who had been exposed to nitroglycol so far.
4. No significant correlation was acquired, however, between ACTH-induced eosinopenia and increment of the steroids.
The general conclusions drawn from the above data are that the pituitary-adreno- cortical functions which were evaluated by Thorn's test and rapid ACTH test decreassed in the workers exposed to nitroglycol, and that the dysfunctions are connected with the outcome of sudden death in case of the serious nitroglycol poisoning.

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To clarify chronic nitroglycol intoxication upon the cerebral activity, electro-encephalographic examinations of nine subjects working in a factory were conducted.
There were only slight and little positive findings in the workers on the sub-jective symptoms and objective examinations except for EEG. Seven subjects out of nine indicated abnormal EEG records both in cases experienced anginal attack and not yet experienced such sign. It can be seen from the EEG findings in workers exposed to nitroglycol that fast activity in all areas was dominant particularly.
Based on these findings, it may be concluded that chronic nitroglycol exposure seemed to influence upon the cerebral activity of factory workers.

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In this report, the following subjects were studied on plant workers :
1. The cardiovascular response to nitroglycerine (NG) of the worker.
2. Follow-up studies of the cardiovascular responses to NG of newly employed packers.
3. Difference in the cardiovascular responses to NG of the worker between Saturday and Monday morning.
4. Differences of the autonomic nervous activities of the worker between Saturday and Monday morning.
And the following results were obtained :
1. The cardiovascular responses to NG of the worker were less than those of the control.
2. The responses to NG of the newly employed packer showed a tendency to decrease with longer duration of employment in the plant.
3. In general, the cardiovascular responses to NG of the worker on Monday morning were greater than those taken on Saturday morning in comparison with the control.
4. There was no difference in autonomic nervous activities of the worker between Saturday and Monday morning.
5. The lowered susceptibility to NG of the worker was acquired not only in the feeling of headache but also in the cardiovascular system.
6. The influences of nitroglycol and nitroglycerine to the worker were classified into three types.

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Marked effects of nitroglycol on superprecipitation of actomyosin and on the initial burst of ATP decomposition by actomyosin were observed in vitro experiments. Instantly after incubating actomyosin with 0.22000 μM of nitroglycol, both super- precipitation and the initial burst were suppressed, while after 24 hours' standing at 0°C, they were strengthened reversely. The reverse effect of nitroglycol on actomyosin was explained as being due to the structural changes of actomyosin in respect of α-helix content. In a previous study, we have found out that actomyosin prepared from poisoned rabbits differed from normal one. Probably actomyosin and thus muscle fiber also of poisoned animals may be in disturbed states in respect of its structure and function.

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When a shaft is sunk by the well sinking method with air blowing, the edge point of the well sometimes meets a hard sedimented soil or a weathered tertiary rock. In these cases the power of detonating explosive is usually utilized to break such a soil or a rock under the cutting edge of the well.But the procedures employed in these blastings are mostly based on experience only and we know some wells sunk in the past had been broken by a blast due to the unsuitable amount of charge of explosives.
Now, the authors have carried out some fundamental investigations on the phenomena related to the underwater explosion in a shaft with the object of obtaining the useful data for the design of blasting operations to sink the shaft well more effectively and safely.
The main results obtained are as follows:
1) In the range of depth, about 200m from the water surface, the pressure pulse always propagates in water with the velocity of 1, 500m a second.The peak pressure decays with the exponent of 1.76 against the distance and it has nothing to do with the kind of explosives used.
2) Shinkiri , a gelatine , when sealed tightly in the pressure-proof vinyl tube, can be detonated in water with 200m from the water surface.
3) When we indicate the index of power of underwater explosion exhibited by Shinkiri as 100, the corresponding indices for Shoan , an ammonium nitrate , and the black powder can be represented as 62 and 48 respectively.
4) If we perform an underwater blasting at the depth of 200m, nearly twice much explosive is necessary to get the full crater compared with the amount needed near the water surface.

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The relationship between rockfall and vibration of the ground has never been fully analyzed before in Japan because of several problems which fall within one of two categories which we have labelled “motivecause” and “primary cause”.
Problems falling within the “motive cause” category are concerned with characteristics of vibration whilethose problems falling within the “primary cause” category are concerned with the conditions of mountainslopes (e. g. morphometric parameters of slope; shape, size and depths at which blocks have been buried onslopes ; quality of weathered materials and surface soil).
In spite of these problems, it is quite important to analyze the relationship between rockf all and vibrationof the ground for some kinds of construction works such as railway and tunnel construction because shocksfrom blasting may cause rockfalls.
In our survey, two seismic tests were carried out-one involving a blast and the other involvinga shockwave caused by a passing train.The results of these tests can be summarized as follows:
1. The shock that was produced by the passing train did not cause a severe rockfalls. The maximum deformationof the ground was 7.6-10^-5 cmand occurred above 10 seconds. These results are too small tocause a rockf all.
2. The relationship among the amount of , the maximum displacement, the maximum accelarationand the transmissive velocity of vibration was studied to find the point at which a severe rockfall waslikely to occur during tunnelling work.In this test, 3 kg of were exploded 50 meters from the test site. As a result, the maximumdisplacement was 1.4-10^-3 cm. This value is also too small to cause a rockfall.

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