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Volume 4 (1954 - 1955･･･
- Issue 2 Pages 33-
- Issue 1 Pages 1-
Volume 4, Issue 2
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Paper
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Jun MIYAMA, Kaoru KITA, Toshihisa USUBA1955Volume 4Issue 2 Pages 33-34
Published: 1955
Released on J-STAGE: March 27, 2015
JOURNAL FREE ACCESSIn this report the relation between the impressed voltage V and the filament current I was investigated, using resistance tubes recently completed. And the power n in the formula V=KυIn was found to distribute between 1.64 and 1.78.
Although these values are slightly apart from the desired value 1.85, we found that these tubes are capable to be applied to practical cases within errors of several percent by the next method.
This method is to compare the calculated values of Kυ and the experimental ones of simple networks of the tubes.View full abstractDownload PDF (265K) -
Iwao OKI, Keizaburo OKAJIMA1955Volume 4Issue 2 Pages 35-38
Published: 1955
Released on J-STAGE: March 27, 2015
JOURNAL FREE ACCESSIn order to ascertain discharging capacities for fire extinguishing purpose of the municipal water supplying nets, we performed 2 experiments besides one preliminary at one section of Kanamachi Katsushika-Ku, Tokyo.
Experiments were made to ascertain natural hose discharging and pump discharging capacities under the case of (1) single pipe line, (2) nets lines. We have computed the discharging amount of Qc from the total friction loss of lines by using Darcy’s formula for old cast iron pipe, and compared with the values Qo measured from experiments.
In these experiments mercury manometer was used at the coupling between hose and nozzle for the accurate measurement of Qo.
We have found that in the 1st experiment the value mean of Qo/Qc is 0.31 and the 2nd is 0.40, that is the discharging capacity is about 30～40% of that for the case of cast iron pipe where Darcy’s formula was applied.View full abstractDownload PDF (342K) -
Takashi SEKINE1955Volume 4Issue 2 Pages 39-41
Published: 1955
Released on J-STAGE: March 27, 2015
JOURNAL FREE ACCESSThe vertical distribution of mean wind velocity over the city was fitted to the logarithmic law as follows:
u=(u∗/k) ln ((z-d)/z0)
where u∗, k, z0 and d denote the friction velocity, Kármán’s const., roughness length and zero plane displacement, respectively.
On the relation between the roughness parameter (d and z0) and the roughness on the ground carried out the experiment by models in the atmosphere. The models are the boxes made of the wood, 200 × 60 × 30 cm in size. This models were stood at an intervals of some distance at right angle to the wind direction and measured the wind velocity behind the box by small cup anemometers. From the results, d and z0 are proportional to the height of the model but vary with D as are shown in Fig. 5 and Fig. 6.View full abstractDownload PDF (264K) -
Tsuruji OKAWA, Shigenao MURAYAMA, Iwao KAWASHIMA, Tadashi WACHI1955Volume 4Issue 2 Pages 42-45
Published: 1955
Released on J-STAGE: March 27, 2015
JOURNAL FREE ACCESSIt is considered that the amount of water used to put out fires by the solid stream application is 50 to 200 times the necessary water consumption theoretically calculated.
The fog flow of nozzle pressure 100 psi has been taken as a counter measures to cope with this problem, and it seems to be our urgent need to make good use of the fog application so as to increase the extinguishing efficiency of water and decrease the water damage to property.
We carried on the subject study so as to analyze the extinguishing efficiency of the fog stream on application-range of discharge, angle of discharge, duration of application, etc.
The No.12 Fog nozzle of Tokyo Metropolitan Fire Board Standard was used in our tests, because this nozzle showed the best operational and characteristic features among all the tested nozzles in the last year’s experiments.View full abstractDownload PDF (389K) -
Yohei KUMANO1955Volume 4Issue 2 Pages 46-48
Published: 1955
Released on J-STAGE: March 27, 2015
JOURNAL FREE ACCESSDescription is made briefly of a high-speed cinematographic technique newly developed by the author for recording the manner in which a fire stream disintegrates as it penetrates through air. The essential of the new method is that the motion of a stream fraction after its emergence from a nozzle-tip is followed up for a definite distance by means of a tilting mirror placed at about 45° to the axis of the high-speed camera lens. To give some indication of the merit of the new method, selected frames from a film taken of a 3/4", 60#/□" stream are reproduced.View full abstractDownload PDF (556K) -
Ken-ichi USUI1955Volume 4Issue 2 Pages 49-51
Published: 1955
Released on J-STAGE: March 27, 2015
JOURNAL FREE ACCESSIn the paper Vol.3 No.1 the experimental formulas for the rational value of the water poured to the burning timbers were obtained. In this paper, the differences between the water used to extinguish actual fire and the above rational value are examined from the following four causes :
(1) Parts of water are poured to something except the burning timbers.
(2) Parts of water are over to the rational value.
(3) Water poured during changing the positions of the nozzles is generally useless.
(4) Water is repeatedly poured to the same timbers.View full abstractDownload PDF (237K) -
Masao OKANOUE, Katsura INOUE1955Volume 4Issue 2 Pages 52-54
Published: 1955
Released on J-STAGE: March 27, 2015
JOURNAL FREE ACCESSThe boundary lines of the burned areas were surveyed about forest fires, and following results were obtained.
1. It is very easy to stop the advancing fire at the edge situated to the windward of the fire.
2. When the fire runs up the win d-swept slope, the fire is easily put out in the windshadow of the edge, but when the edge is flat or the slope is gentle the fire may run over the fire lines and especially it often happens when there are dense, inflammable stands such as Hinoki, Akamatsu, Sugi and bushes.
3. When the wind velocity is small, and air humidity is high and the burning force becomes low it can be easily put out in the windshadow on the slope.
4. When the conditions of such elements as fuel, weather and topography are favourable, the self-extinguishing lines are also observed in forest fires.View full abstractDownload PDF (299K) -
Kazuo AKITA1955Volume 4Issue 2 Pages 55-58
Published: 1955
Released on J-STAGE: March 27, 2015
JOURNAL FREE ACCESSThree types of ignition in wood, Ignition, Flashing and Carbon-ignition, are classificated experimentally by difference of time lag. By this results, the following facts are made clear : —
(1) Three types of ignition are recognized at low temperature (<600°C).
(2) Three types are not separated at high temperature.
(3) Carbon-ignition break out more easily than flashing and ignition.
(4) Carbon-ignition is not obtained when air flow on the surface of wood is ceased.
(5) The theory given at the last report is applicable in flashing phenomenon.
Moreover, activation energy of thermal decomposition 36.9 kcal is determined from the theory in the last report and the results of experiment in this report.View full abstractDownload PDF (424K)
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