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一様な磁場を横切る電導性流体の脈動流 I 二次元理論
Get PDF論文(Article)The pulsating flow of an electrically conducting viscous incompressible fluid in a rectangular duct with a uniform transverse magnetic field is considered theoretically with the assumption that the flow is supposed to be the parallil flow. The walls of duct which are parallel and perpendicular to the imposed magnetic field are taken to be perfectly conducting (as the electrodes) and nonconducting, respectiveiy. Exact solutions for the velocity, magnetic field, instantaneous volumetric flow rate, the current density and the potential difference of the electrodes are obtained taking the longitudinal pressure gradient as a given function of time. The imposed conditions can be represented by the Reynolds number, the Hartmann number, the magnetic Prandtl number and the variation of time dependency for the pressure gradient. The effects of the strengths of the imposed magnetic fields and the amplitudes of the pressure gradient on the pulsating behavior of the flow are remarkable for the velocity profile and the induced fields
A Graphical Method for Solving the Symmetrically-Mixed Equations of Electrical Networks with Switching Elements
Get PDF論文(Article)Abstract Using properties of tree and cotree determinants, a graphical method for solving the symmetrically-mixed equations of electrical networks with switching elements is obtained from mixed immittance products expressed by summation convention and alternation. The unknown quantities of these equations are point-potentials and loop-currents. All solutions of the equation can be read from the corresponding graphs directly. Several examples on practical networks are also described. 対称混合解析は電気回路網が開閉素子をもつとき特に有用である。先に著者らは，この解析の中で回路の点電位及び閉路電流を未知数とする対称混合方程式とその代数的な解法を示した。 本文では，その拡張として，この方程式の解が図解法によっても求めることができることを，例題と共に紹介する
石炭液化溶剤の設計
Get PDF論文(Article)Abstract To clarify interactions between coal liquefaction solvents, Yallourn, Wandoan and Taiheiyo coals were liquefied in binary solvent systems composed of hydrogen donor (tetralin) and non-donor, and hydrogen donor ability (HDA) of binary solvent systems were evaluated quantitatively by using anthracene as coal model. Coals were readily liquefied by adding fluorene, phenanthrene, indene or sulfur in tetralin. Non-donor solvents were not effective if they were used alone, however,dehydrogenation reaction of tetralin was accelerated by the addition of above solvents. This fact suggested the presence of hydrogen shuttling reaction. Harmful effects on coal conversions were observed when n-paraffin or 1-olefin were mixed with tetralin or indene. The HDA scale reflected the results of coal conversion very well. However, HDA of tetralin-phenanthrene and tetralin-sulfur mixture was underestimated because hydrogen accepting ability of anthracene was lower than that of coal fragment. In previous paper, HDA of 26 kinds of anthracene oils was correlated wel1 with conversion ratio for Yal1ourn and Taiheiyo coal. Present results indicate the possibility of the presence of coal fragmentation via hydrogenation at ipso position in addition to direct thermal fragmentation. In the solvent extracting liquefaction methods, HDA scale defined in this study is one of the most important characteristics of coal liquefaction solvent
超小型ファンの試作及び特性試験に関する研究(多翼ファンの場合における形状寸法の影響)
Get PDF論文(Article)A micro-downsized radial-flow fan (Sirocco Fan) was designed for the local cooling of electronic devices and its performance was tested in order to analyze the scale effect. The outer diameter of the rotor is 8mm, and the blade chord length, the blade width and the blade thickness were about 2mm, 8mm and 0.2mm, respectively. The variable parameters to examine the scale effect were the diameter ratio D_1/D_2 of the rotor inlet to the outlet (0.4~0.75), the number of blades (8~20), scroll angles (6^o~12^o) and the number of rotor revolution (3750~8500rpm). It was found that the optimun. D_1 / D_2 was about 25% smaller than that of a non-downsized Sirocco Fan and the flow rate was considerably affected by both the blade thickness and the number of blades
粉炭比重の試作ならびに石炭灰分定量への応用
Get PDF論文(Article)Abstract A new type of specific-gravity meter was devised for measuring rapidly the speciflc gravity of fine coal. Several kinds of coals and glass beads were used to examine the utility of this meter. Specific gravities of these materials measured by this meter were found to agree well with the values measured by Beckman's density meter which was commertially available, and it was concluded that the accuracy of the devised meter was high enough for industrial use. The ash content of coal was also measured according to JIS M 8812. An empirical equation expressing ash content-density relation was proposed for each coal. Conclusively, the specific-gravity meter devised here would be useful for rapid and accurate estimation of ash content of the fine coal
新しい型の高周波発電機について(第2報)
Get PDF論文(Article)In the former report, part 1 stated the theory and the experiment of a new electrostatic type high frequency generator. In this paper, the construction of the second machine is discussed and theoretical results are compared with experimental observations on its resonant states, wave form and performance as frequency changer. Then the methods of design, mechanisms and materials of the electrodes, new ideas on another type and etc. are described
山形大学シラバス処理システムの稼働状況の分析
Get PDF論文(Article)Performance analysis of the syllabus database system of Yamagata University has been carried out from January 1999 to March 1999. During this period, 3304 syllabusses were processed and their manuscripts were updated 23409 times in total. The cost for facsimile calls used to verify the manuscripts was reduced to 1/6 by using web based input system than that of e-mail based system operated at 1998. The stability and throughput of the web based input system was improved by optimizing the access condition settings of web-subsystem
燃料油(重質油)の蒸発について
Get PDF論文(Article)前報において，モーターガソリンおよびディーゼル軽油について定常蒸発過程における蒸発速度係数の実験式を導いたが，重油についても同様な関係式が導けることを示した。 (1) 定常蒸発初期について蒸発速度式から線蒸発率を導き，これから蒸発速度係数ｋおよびｋ''を求め，同一燃料油について，ｋおよびｋ''を炉温Θ_gと初めの油量Ｗ_の関数として実験式を導いた。 (2) 定常蒸発初期以降について，すべて燃料油について同一炉温では油の初めの重量に関せず蒸発率はｑ=ｋ'・logｔで表わされ，蒸発速度係数ｋ'は一定である。 ここに，ｑ:単位面積当りの蒸発率 (1/c㎡) ｔ:蒸発時間 (ｍｉｎ
試薬中の微量銅の迅速発光分析法JIS分析法の迅速化に関する研究IV
Get PDF論文(Article)There are lots of methods for the purifications of chemical reagents. The maximum allowable quantities and analytical procedures for various impurities in chemical reagents are prescribed in the Japanese Industrial Standard (JIS), respectively. It is not so easy, however, to determine a large number of impurities in a limited time by an ordinary analytical procedures In the previous reports, the rapid semiquantitative spectrographic procedures were progressed for the determinations of microquantities of iron and lead in the various chemical reagents which are on the market. In the present report, copper was checked as an impurity in the chemical reagents. For the spectrographlic determination of microquantity of copper in chemical reagents, the samples were dissolved in water. Metallic samples were treated with a diluted nitric acid and dissolved in water. The solution prepared was added to the carbon electrode as a supporting electrode. The electrodes were excited by the spark method. The addition of the sample solution and the spectrographic excitation were repeated for three times. The procedures above are the same as the previous report's. For the rapid semiquantitative spectrographic determination of copper, the suitable wave lengths of copper were 3273.96A, 2246.99A and 2369.88A, etc. It was also investigated that the simultaneous determinations of copper and lead in chemical reagents, and the foreign substances for the described method
曲がり部に集中荷重をもつU形わく組の振動
Get PDF論文(Article)The vibrations of a U-type frame work which consists of three straight bars and has a concentrated load at each bend are studied The frame work is in a plane and symmetric about its midsection. The centre of gravity of the concentrated load coincides with the point of the bend of the U-type frame work. The Lagrangian of this frame work is equal to the Lagrangian of the three straight bars plus the Lagrangian of the two concentrated loads. The frequency equations and the boundary values are obtained by minimizing the Lagrangian with respect to the unknown boundary values. The vibrations in the plane of the frame work and in the direction perpendicular to its plane are respectively divieded into the symmetric vibrations and the anti-symmetric. Accordingly, the vibrations of this system are classified into four sorts of the normal vibrations. The fundamentaI nondimensional frequencies of each normal vibration are calculated and shown in graphs. The experiments are carried out and their results are compared with theoretical ones