巻号一覧
57 巻, 671 号
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小田川 達朗, 嶋野 宏1941 年 57 巻 671 号 p. 119-127
発行日: 1941/03/22
公開日: 2011/07/13
ジャーナル フリーThe object of this paper is to obtain information regarding the rock-pressure vectors of the strata in longwall working, and the effect of easier coal-getting and greater safety in regard to falls of rock.
By the analytical study of Coal-Measure Strata as a continuous beam, together with the underground observation of prop resistance by dynamometer, the authors deduce the following conclusions:-
(1) It has been observed that when a longwall face is newly advanced, either of the two different types of pressure dome is built in the immediate roof strata at right angles to the face; the one, the smaller, bridges over between the coal face and the front of packs, and the other, the larger, crosses between the solid coal and the settled packs.
(2) The smaller dome, surrounded by “Semi-pressure-relief zone” is the most important of many factors controlling the roof pressure, as it greatly reduces the pressure on the coal face, although it is essentially impermanent.
(3) In order to maintain the roof in good condition and also render coal-getting easeful, the building of “Semi-pressure-relief zone” or the lowering of roof is recommended.
(4) Although abutment pressure, which acts well in advance over the solid coal, is less than the average shearing strength of coal, it can break coal due to fracture cleavage and fatigue due to repeated stress.
(5) The rate of face advance alone can not bring about effective roof control. It is the convergence advance ratio that is strongly in favour of roof control, and may be taken as an index of the efficient working.抄録全体を表示PDF形式でダウンロード (4457K) -
井上 克巳1941 年 57 巻 671 号 p. 128-142
発行日: 1941/03/22
公開日: 2011/07/13
ジャーナル フリーThis article deals firstly with the present day scrap-iron problem for the melting of special steel. The author, emphasizing the necessity of using high grade metal as raw material, describes on the manufactures and properties of various kinds of virgin iron as a substitute for scrap iron.抄録全体を表示PDF形式でダウンロード (5397K) -
伊藤 尚1941 年 57 巻 671 号 p. 143-152
発行日: 1941/03/22
公開日: 2011/07/13
ジャーナル フリーThere are various difficulties in the electrolytic refining of tin. Among them, its anodic passivation is a fatal trouble. The author studied the passivation of pure as well as impure tin anodes in the electrolytes of H2SO4, H2SiF6, and their mixtures, each containing 0.5 N Sn. The present paper concerns to the pure tin anode alone.
The anodic Dassivitv of tin is of a mechanical nature. caused by the formation of films of certain tin compounds op the anode surface. The formation of Such films is observed distinctly under microscope during electrolysis. The passivation is easy in H2SO4, and difficult in H2SiF6. This tendency is also the case in mixed electrolytes containing H2SO4 and H2SiF6 in varying proportions. The nature of passifying film is as follows: In H2SO4, basic SnSO4 deposited from oversaturated solution next to the anode surface; in H2SiF6, basic SnSiF6 deposited probably from unsaturated solution; in mixed electrolytes, normal SnSO4 crystal deposited from oversaturated solu-, tion (hydrolysis of SnSO4 is prevented by the presence of H2SiF6).
In short, the tin electrolyte must have small hydrizing tendency and large solubility of tin salt. The electrolyte composed of more or less 0.5 N Sn, 1.0 N total H2SO4, 1.0 N total H2SiF6seems to be the most suitable one.抄録全体を表示PDF形式でダウンロード (3136K) -
三野 英彦1941 年 57 巻 671 号 p. 153-164
発行日: 1941/03/22
公開日: 2011/07/13
ジャーナル フリーThe bibliography of recent literatures on ore dressing was compiled, successively.
It consists of literatures mainly on non-metallic minerals, including aluminium ore, asbestos, barium ore, clay, diatomaceous earth, dolomite, feldspar, fluorspar, graphite, gypsum, kaolin, kyanite, limestone, magnesite, mica, phosphorous ore, potash ore, sulphur ore, and talc.抄録全体を表示PDF形式でダウンロード (2593K) -
1941 年 57 巻 671 号 p. 165-173
発行日: 1941/03/22
公開日: 2011/07/13
ジャーナル フリーPDF形式でダウンロード (2330K)
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