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Volume 6 (1956 - 1957･･･
- Issue 2 Pages 33-
- Issue 1 Pages 1-
Volume 6, Issue 1
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Displaying 1-8 of 8 articles from this issue
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Paper
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Hiroshi YAMANOUCHI, Susumu KASEI1956 Volume 6 Issue 1 Pages 1-4
Published: 1956
Released on J-STAGE: November 11, 2014
JOURNAL FREE ACCESSWhen machines are exposed to fire, they lost their accuracy. We studied the change of accuracy for some parts of the fire damaged machines.
At the start we measured the flatness of the lathe-bed exposed to fire and have found that the deformation at the sliding surface is considerable and different amount. Because we could understand this difference as the fired condition, we had made experiments by the model of the lathe-bed using the electric furnace under the variation of temperature, time and the after treatment of the fired material. As a result of experiments we could have found the surface deformation was made less progress until 600°C, but marked change was pointed out during 600°C to 800°C. The more temperature rise causes the speedy loss in accuracy and the watering on the heated parts had shown the remarkable deformation and the hardness increase.View full abstractDownload PDF (463K) -
Tosirô KINBARA, Nobuo IWASAKI1956 Volume 6 Issue 1 Pages 5-8
Published: 1956
Released on J-STAGE: November 11, 2014
JOURNAL FREE ACCESSIt has been well known that the carbon has three states of aggregation : amorphous, graphite and diamond, among which graphite is a good conductor, whereas the other two are non-conductors. When wood materials are heated, they are at first turned into the amorphous carbon, and if we keep heating them for a long time, they gradually are converted into the graphite. And the higher the temperature of heating, the shorter is the time necessary for the conversion.
Now in a long run of the electric leakage, through wire-laths inside the wall of houses, the wire would be burned down, and at this moment of breaking, an electric arc of a very high temperature would appear and heat the surface of the wood materials, changing them into graphite in an instant. Then the current passes through the graphite surface and, keeping it white-heated, the current makes the neighbouring layer of wood change into graphite again. Thus the carbonization progresses deeper and deeper to the inner part, and at last the wood materials come to emit flames, resulting an outbreak of fire in the wall.View full abstractDownload PDF (500K) -
Kikuji TOGAWA1956 Volume 6 Issue 1 Pages 9-14
Published: 1956
Released on J-STAGE: November 11, 2014
JOURNAL FREE ACCESSThe author previously had presented the formula about the time necessary for escape of the crowd in emergency, basing on the results of observation of the current of the crowd at a station.
In this report, this formula was applied to the current at other three places and compared with the observed results.View full abstractDownload PDF (564K) -
Kunio KAWAGOE1956 Volume 6 Issue 1 Pages 15-18
Published: 1956
Released on J-STAGE: November 11, 2014
JOURNAL FREE ACCESSThe results of fire-tests on beams, channel-type slabs and plate-like slab members of prestressed concrete for building structural use was shown in this paper.
The behavior of prestressed concrete under fire tests is remarkably different from that of ordinary concrete in the point that the surface of the concrete has begun to spall out explosively in a few minutes after heating.
The test results have shown that prestressed concrete of thin thickness suffers vital damages by a fire and so its fire resistance can be said to be very poor.
The explosive spalling is due to the vapour pressure of the heated water within concrete voids which has no way of escape of water-vapour since the concrete is very dense.
Prestressed concrete slabs provided with non-combustible ceiling or covering, endured Class III fire exposure, specified by Japan industrial standard A 1302, which corresponds to one hour fire in United States and British specifications.View full abstractDownload PDF (485K) -
Hiroshi MORIMOTO1956 Volume 6 Issue 1 Pages 19-22
Published: 1956
Released on J-STAGE: November 11, 2014
JOURNAL FREE ACCESSAuthor studied on the combustibility of the chemically treated wood by thermo-balance, heating to standard temperature 260°C, which is used for estimating of fire-proofness of construction materials in Japan.
The results are as follows :
(1) From the tests of wood treated with many chemicals, it was found that some chemicals checked the heat decomposition of wood and the others extraordinarily accelerated. Therefore, the fire-proofness of the wood depends upon the treating chemicals.
(2) The velocity of heat decomposition of the strong alkali treated wood is very slow and proportional to the alkalinity
(3) The heat decomposition velocity of acid-treated wood is more rapid than the alkali treated.
(4) The heat decomposition velocity of the heavy metal salts, such as CuSO4, FeSO4, FeCl2 and CuCl, treated wood, is much larger than the ones treated with other chemicals.View full abstractDownload PDF (361K) -
Yorio YAZI1956 Volume 6 Issue 1 Pages 23-26
Published: 1956
Released on J-STAGE: November 11, 2014
JOURNAL FREE ACCESSThe burning speed of cotton surface and the effect of the filling up density for the ignition temperature of cotton is investigated.
The upward burning speed of cotton surface becomes very fast when the angle of its surface is larger than 45 degrees, and the downward speed is scarcely affected.
The effect of filling up density on the ignition temperature of cotton is that the ignition temperature decreases exponentially as the density increases.
View full abstractDownload PDF (484K) -
Minoru HAMADA1956 Volume 6 Issue 1 Pages 27-29
Published: 1956
Released on J-STAGE: November 11, 2014
JOURNAL FREE ACCESSThe formula for the calculation of the time of extinction proposed by Dr. HISHIDA is used in practice, but it is not perfect in theoretical viewpoint, and by which, the burnt area can not be obtained in theoretical way.
The author proposes new formula for the time of extinction and for the burnt area under theoretical consideration.
Some numerical examples by the author show that the difference between above two formulas is quite small in most cases, but in some cases there occur great difference.View full abstractDownload PDF (267K) -
Koichi TUKAMOTO, Saburo TOGASHI1956 Volume 6 Issue 1 Pages 30-32
Published: 1956
Released on J-STAGE: November 11, 2014
JOURNAL FREE ACCESSIn order to study a fire caused by the electrical leakage current which flows in lath wire of the lath-mortared houses, built of wood, we have tried to flow electrical current practically in lath wire of the actual houses and measured the amount of it.
The experiment reveals the following facts :
1. Leaked current is much influenced by the resistance of lath wire, especially of its contact part.
2. The contact resistance shows a great difference after the current runs actually.View full abstractDownload PDF (286K)
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