1970年から開催されている「

椅子バスケットボール選手権大会」は男性選手のみの出場に限られていたが、2017年から男女混合チームの出場が可能となった。また椅子バスケットボール連盟は、One Team Projectを立ち上げ選手の強化育成に努める等、女性選手を取り巻く競技環境が変化している。そこで、女性選手が日々どのようなことを感じながら競技に打ち込んでいるのか、競技活動と日常生活との両立から生じる葛藤や要望等を「生活観」として、その実態を明らかにすることを本研究の目的とした。

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椅子バスケットボール連盟に選手登録をしている女性選手１名を対象に、ナラティブの視点を取り入れた複数回のインタビューとイスバス日誌（活動で感じたこと等をまとめたもの）によって行った。「普段練習している男女混合チームで求められるプレーと女子のみのチームで求められるプレーが異なっている」ことから選手としてのプレースタイルの確立が不安定であること、「ロールモデルとなる選手も少ないので、どのようにプレーしたり、どのようなキャリアを積んでいけるのか将来の見通しがもてない」等の不安や悩みを抱えていることがわかった。

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  There is a kind of casting requiring two or more risers which can be set at clearly different levels of casting and can be numbered according to the levels as 1, 2, ⋅⋅⋅i, ⋅⋅⋅n. During freezing of the casting, unfrozen liquid metal in some of the risers flow through the casting body. Therefore, the liquid metal reserved in the riser at the highest position in that part flow into shrinkage cavities generated in the lower risers. Riser equations for a casting requiring multiple risers with consideration of the metal flowing into or out of a riser to others were derived. Generalized form of the riser equation for a i th riser is as follows :
    F_cti={[F_rk / {(V_ri+V_ei)(1−β)/V_ei}−β]+B_k}(V_ri / V_ei^2/3)          (1)
where, F_cti is A_cti ⁄V_ci^2/3, a shape factor of a heavy section with the i th riser, A_cti is surface area of a heavy section with the i th riserincluding area of riser/casting interface, V_ri and V_ci are volume of i th riser and its heavy section respectively, F_rk = π(1 ⁄ 4 + K)/(πK ⁄ 4)^2/3 (K is height of riser/diameter of riser), B_k = (π/4)^1/3(1/K)^2/3, β is fraction of solidification contraction (0.05 for steel), V_ai is volume difference of liquid metal flowing into and out of the i th riser defined by formula (2).
    V_ai = β M_oi{(F_rk−B_k)V_ri^2/3 + A_cti}−β??(M_i,_j−M_oi){(F_rk−B_k)V_rj^2/3 + A_ctj}    (2)
where, M_oi is modulus of a thin part connecting heavy sections in which part the freezing of the whole section cuts off the metal flowing into the i th riser, and M_i,_j is modulus of thin part connecting heavy sections in which part the freezing shuts the metal flowing between the i th riser and the j th riser. The riser equations of each riser i=1, 2, ..n can be solved in the order of n, (n−1), ⋅⋅⋅2, 1 for each heavy section having shape factor (F_eti) larger than about 5.7. From this, the minimum adequate volume of risers can be determined.

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  A riser equation considering the solid volume solidified during pouring is derived as follows :
    [Written in non-displayable characters.]
where; F_ct=A_ct/V_c^2/3, shape factor of casting, A_ct=total surface area of casting including riser-casting contact area, V_r, V_c=Volume of riser and casting, K=(height of riser) / (diameter of riser), β=Fraction of solidification contruction (0.05 for steel), V_f=solidified volume in the casting during pouring.
  It is found that the adequate volume of riser decreases as the volume solidified during pouring increases. For a cube shape steel casting, pouring so as to make the ratio V_f/V_c be equal to 0.3, the riser determined from the equation behaved as the optimum riser. A riser equation is derived on a condition of pouring additional melt to fill the shrinkage cavity formed in the riser after the first pouring. The required volume of riser for additional pouring decreases by increasing the volume of solid solidified in the casting befere additional pouring.

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  A equation computing exact dimentions of cylindrical risers with consideration of the contact area of riser to casting is derived as follows :
    F_ct=(π/4)+πK ⁄ ((πK/4)^2/3)⋅(V_r/V_c)^2/3 ⁄ ((1−β)(V_r/V_c)−β) + (π/(4))^1/3(1/(K) V_r/(V_c))^2/3⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅⋅(1)
where;   F_ct=A_ct/V_c^2/3, a shape factor of casting
    A_ct=Total surface area of casting including riser-casting contact area.
    V_r, V_c=Volume of riser and casting, respectively
    K=height of riser/diameter of riser
    β=fraction of solidification shrinkage (0.05 for steel).
  The value of K corresponding to the minimum value of V_r/V_c, which gives the most efficient riser, varies as a function of F_ct, but the K can be practically regarded as a constant 0.75 for any values of F_ct. It is found that Bishop-Pellini's diagram showing the relation between the simplified shape factor (L+W) / T (L, W, and T : length, width and thickness of casting) and the minimum effective riser volume as a fraction of casting volume V_r/V_c can be derived from equation (1). From the results of experiments on cube and T-shaped test castings, it wsa found that the risers determined from equation (1) behaved as the optimam riser.
  Nomograms for rapid determination of heights and diameters of the minimum adepuate risers having K=0.75, 1.0 and 1.5 from volume and modulus (V_c/A_ct) of any given castings are presented, which are derived from an approximate formula against equation (1). These nomograms have sufficiently high accuracy for practical use. In applying the nomograms for a casting consisting of a principal part (the most massive section) and appendages (the thiner sections), the modulus of the casting must be calculated from the volume and surface of the principal part alone, but the casting volume can be calculated from the sum of the volumes of the principal part and the appendage.

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In order to improve the lateral riding quality of railway vehicles, various type of Full-Active or Semi-Active Suspension Systems have been developed and in use. Semi-Active System is announced more useful in energy saving and fail-safe than Full-Active System; but the efficiency of Semi-active System is half of Full-Active System and is none in the crossing section. So we have been researching new control method to improve the skyhook Semi-Active System. One of our trials is a Collaboration Control of Semi-Active damper and Short Stroke Actuator in series connection. As a result, we have achieved the decrease of lateral acceleration to the level of Full-Active System with small energy.

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Aluminum hollow structure is adopted to railway carbodies to improve specific stiffness, but the acoustic transmission loss property of the hollow structure has not been examined in detail. We study the transmission loss with numerical analysis technique, and find out that the transmission loss is worse than the single plate with equivalent mass at the frequency, at which the 1st vibration mode of each plate element separated by rib is excited. This phenomenon occurs to arbitrary cross section structure with rib, therefore it is not easy to simultaneously improve the specific stiffness and the acoustic transmission loss property. We find that the numerical analysis result coincides with experiment data very well.

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Recently, the crashworthiness provision of the railway cars has been required worldwide. Using the mechanical dynamics analysis code ADAMS, the simulation element models of the carbody end structure (crushable zone) and the coupler and draft gear between cars have been developed, and applied to the crash simulation of train set and a truck. The simulation adapting 15 cars train set indicated the good results, that is, the behavior of cars, crushable zones, and draft gears was shown in detail.

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Incompressible finite element flow analysis and acoustic calculation are combined to predict the far field aerodynamic noise radiated from a side door on a high-speed train running at 75m/s (270km/h). The acoustic calculation is based on the assumption that the unsteady flow field is not influenced by the sound field. Also it is assumed that the contribution of volumetric quadrupole source term is smaller than that of dipole source term. The results of flow analysis are compared with experimental measurements on an actual train in terms of pressure fluctuation, the phase velocity, and the coherence between the pressure probes.

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Studies were made on solidification and cooling of sand mould castings of various shapes by temperature measurements and pour-out tests. W-Fe and W-Mo thermocouples were used for the temperature measurement, as they were more convenient and economical than Pt/Pt-Rh thermocopules to use for the work of this kind. Results obtained were summarized as follows: (1) The rate of skin formation at the early stage of solidification of cylindrical steel castings, with and without chills, was determined by pour out tests. (2) Many cooling curves were obtained at the centres and the surfaces of cylinders of various diameters. In the whole range of diameter of the steel castings, the metal surface instantly cooled to 1350°∼1400° and was kept in this temperature range until freezing of the centre began. (3) The cooling curves obtained at the centres of risers and the casting surfaces of some rollingstock parts showed that the thin part next to a heavy section, such as a spoke of a locomotive driving wheel casting, cooled irregularly due to thermal influence of the heavy section. (4) The surface temperature of a core set near the centre of a large mass of cast steel such as the boss of a wheel casting was found to rise gradually from 1350° to the liquidus temperature. This temperature rise was considered to be a cause of secondary metal penetration into the mould.

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In the 1st report of this paper, there were described the distinctive features of the brittle fracture of this kind, and the influences of heat treatments on it, especially of coolings processes after the solidification. Thus it became evident that the embrittlement is caused by the precipitation of some material on the grain boundaries of primary austenite, when some particular part of a large steel casting cools in such an unusual manner as described in that report.
Later, the influence of chemical composition has been studied and aluminium and nitrogen are found to be the most important elements that increase the tendency of this embrittlement. After all, this kind of brittle fracture is considered to be much the same with what is called “rockcandy fracture”. Lorig showed with considerable evidence that this kind of fracture is due to precipitation of aluminium nitrides. Results of the anthors’ study on the test blocks attached to the bosses of driving wheel casting show that steel containing nitrogen more than 0.01% with aluminium more than 0.08% very often reveals the brittle fracture when it is broken by the tension test.
Means of prevention are discussed, and addition of small amount (0.5%) of titanium is found to be sufficient for the complete recovery of ductility.

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It is already well known that the grain boundaries of the primary austenite of low carbon steel usually do not coincide with those of the primary dendrites, and also that they have little effect on the mechanical properties after the heat treatment for grain-refining. But the authors have often experienced to observe a remarkable embrittlement occurring at some parts of castings such as spokes and test coupons attached to the bosses of driving wheels of locomotives, in spite of normal heat-treat- ment for grain-refining. The distinctive features of the appearances of this brittleness are as follows: (1) Coarse granular fractures are distinctly observed along the interfaces of grains of primary austenite. (2) In the microscopic specimens, etched with aqueous solutions of 10% HNO₃-10% H₂SO₄ and repolished, network of pit-chains are clearly obeserved. (3) Loss in elongation is not so remarkable. The coarse fractures and pit-chains are gradually eliminated on eating the specimens, partly at about 1300° and entirely at about 1450°.
The authors tried to reproduce the embrittlement artificially by means of monotonous cooling of the specimens from very high temperatures at various cooling rates, but in vain. Later they, however almost succeeded in to do so by keeping the specimens at 1000° for one or two hours after fairly rapid cooling from solidifying temperature. From the results of these experiments, an idea was introduced for the reason why the embrittlement occurred only at the peculiar parts of castings. These parts of castings are rather thin in themselves but they are attached to some large masses, and so they cool rapidly just after the solidification and then very slowly between about 1000° and 800°. So the authors reached the conclusions that the embrittlement would be caused by precipitation of certain elements or compounds along the grain boundaries of primary austenite. This phenomenon may be substantially the same with so called “Overheating”. The physical and chemical properties of the precipitates are not yet investigated.

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The shape design method presented in this study is based on the knowledge of spatial non-uniformity of the response due to specific areal blockage by the vehicle. The method consists of an efficient numerical prediction of the pressure wave and its implementation into a shape optimization technique. A series of transient finite element flow simulations of the tunnel entry is conducted to collect the information of pressure response of the tunnel. Several suggestions for effective reduction of the pressure gradient are deduced from this information. The pressure wave generated by a train is approximated by a composition of the pressure response of the tunnel incorporated with non-linear correction. The shape optimization also utilizes the variation of the pressure response. The pressure wave generated by the optimized shape is verified by the direct simulation and it exhibits a good reduction of the pressure gradient.

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