著者

原,研哉

出版者

日本機械学会

雑誌

設計工学シンポジウム「21世紀のデザイン・ビジョン」講演論文集

巻号頁・発行日

vol.2004, 2004-12-14

著者

渡邉 敬人 藤原 聖司 後藤 裕太 岩原 光男 長松 昭男 新井 和吉 寺西 幸弘 長尾 裕史

出版者

日本機械学会

雑誌

ジョイント・シンポジウム講演論文集:スポーツ工学シンポジウム:シンポジウム:ヒューマン・ダイナミックス

巻号頁・発行日

vol.2006, pp.104-109, 2006

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Recently, baseball bats that have kinds of characters have been marketed due to advances in the materials and structure of modern baseball bats. One of remarkable point is a sweet spot in bats. But a sweet spot is sensuous and its point is laxness. So the reason why a sweet spot is approved is researched in this study. First of all, the first node, the second node and center of impact were measured. Next, the ball was made to collide with them and the repulsion coefficients were measured, and compared.

著者

日本機械学会 編

出版者

日本機械学会

巻号頁・発行日

vol.昭和15年, 1940

著者

FUJII Terushige OHTA Jun-ichi AKAGAWA Koji NAKAMURA Toshi ASANO Hitoshi

出版者

日本機械学会

雑誌

The Japan Society of Mechanical Engineers, Series II (ISSN:09148817)

巻号頁・発行日

vol.35, no.2, pp.319-324, 1992-02

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From the viewpoint of energy conservation and the development of new energy resources,it is important to utilize geothermal resources and waste heat from factories. Among energy conversion device,there is a radial outflow reaction turbine,i.e.,Hero's turbine. Performance characteristics of Hero's turbine are analytically and experimentally clarified for flashing expansion of initially subcooled hot water. It is found that: (a)there is an optimum number of revolutions at which maximum tubine efficiency can be obtained; (b)Hero's turbine internal efficiency can be expressed as an algebraic equation and (c)nozzle loss accounts for almost 90% of the total turbine loss.

出版者

日本機械学会

著者

日本機械学会 編

出版者

日本機械学会

巻号頁・発行日

1939

著者

山本 哲彦 花田 真一 中園 邦彦 金城 寛 玉城 史朗

出版者

日本機械学会

雑誌

日本機械学会論文集. C編 (ISSN:03875024)

巻号頁・発行日

vol.61, no.591, pp.4276-4281, 1995-11-25

参考文献数

3

被引用文献数

5

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In this work we consider unstable control objects such as an inverted pendulum. Two evaluation procedures in genetic algorithm (GA) are set. The first involves the following steps : set two limits, -Θ and Θ, on both sides of the unstable equilibrium point, set an initial point θo in [-Θ, Θ], initiate a motion, measure the time when the motion reaches one limit, repeat simulations of neuro-control, select neural networks in order of length of holding times, and apply GA-crossover to superior neural networks of long holding times. The second involves the following steps : select neural networks in order of shortness of settling time to the equilibrium point, and apply GA-crossover to superior neural networks of short settling times. We adopt only the first evaluation procedure in the early generation stages of GA. After the number of neural networks of controllability reaches a sufficient percentage of all the neural networks in a computer, we adopt the second evaluation procedure, and GA evolution is continued. Neural networks of controllability appear at about the 10th generation and evolve to the ability limit predetermined by the structure of neural networks.

著者

山本 哲彦 吐合 隆拡 中園 邦彦 金城 寛 玉城 史朗

出版者

日本機械学会

雑誌

日本機械学会論文集. C編 (ISSN:03875024)

巻号頁・発行日

vol.62, no.601, pp.108-113, 1996-09-25

参考文献数

6

被引用文献数

2

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Genetic algorithms (GAs) with rough evaluations can prompt the evolution of neural networks that are able to control unstable dynamic systems. The proposed control method exploits the advantage of GAs that time-varying evaluations can be easily incorporated. First an easy evaluation in GAs induces the appearance of neural networks with controllability. Second, an evaluation of settling time prompts the evolution of neural networks that show high performance. The method is applied to the stable control of a bicycle. Neurocontrol of the steering at direction change causes reverse response like that of a human cyclist.

著者

橋本 健 古畑 朋彦 新井 雅隆

出版者

日本機械学会

雑誌

日本機械学會論文集. B編 = Transactions of the Japan Society of Mechanical Engineers. B (ISSN:03875016)

巻号頁・発行日

vol.72, no.721, pp.2323-2329, 2006-09-25

参考文献数

8

被引用文献数

1

---

Six-stroke diesel engine proposed here has six processes in one cycle, i.e. intaka, 1st compression, 1st combustion, 2nd compression, 2nd combustion and exhaust. By the effect of direct EGR in the 2nd combustion process, NO concentration could be expected to decrease. However, by a weak mixing in the 2nd combustion process, much soot was exhausted and NO concentration was hardly decreased compared with the conventional four-stroke diesel engine. To improve the fuel/air mixing at the 2nd combustion process, high pressure injection with common rail system was applied to the engine. As the result, NO concentration was increased owing to the increase of premixed combustion of 1st combustion process, although soot was reduced. Therefore, the 1st injection timing was extremely advanced to control the 1st combustion process. It changed 1st combustion process into HCCI-like combustion, and NO concentration was greatly decreased. Moreover, soot was reduced with no increase of NO concentration in the 2nd combustion process. As the result, trade-off curve of NO and soot was improved compared with the conventional four-stroke diesel engine. But CO concentration was increased.

著者

日本機械学会著

出版者

日本機械学会

巻号頁・発行日

1983

著者

KANAZAKI Masahiro SETO Naoto

出版者

日本機械学会

雑誌

Journal of Computational Science and Technology (ISSN:18816894)

巻号頁・発行日

vol.6, no.1, pp.1-15, 2012

被引用文献数

3

---

Efficient global optimization (EGO) was applied to the multi-objective design and knowledge discovery of a supersonic transport (SST) wing. The objective functions considered here are employed to maximize the lift–to-drag ratio at supersonic cruise, to minimize the sonic boom intensity and to minimize wing structural weight, simultaneously. The EGO process is based on Kriging surrogate models, which were constructed using several sample designs. Subsequently, the solution space could be explored through the maximization of expected improvement (EI) values that corresponded to the objective function of each Kriging model because the surrogate models provide an estimate of the uncertainty at the predicted point. Once a number of solutions have been obtained for the EI maximization problem by means of a multi-objective genetic algorithm (MOGA), the sample designs could be used to improve the models' accuracy and identify the optimum solutions at the same time. In this paper, 108 sample points are evaluated for the constructions of the Kriging models. In order to obtain further information about the design space, two knowledge discovery techniques are applied once the sampling process is completed. First, through functional analysis of variance (ANOVA), quantitative information is gathered and then, self-organizing maps (SOMs) are created to qualitatively evaluate the aircraft design. The proposed design process provides valuable information for the efficient design of an SST wing.

出版者

日本機械学会

雑誌

日本機械学会論文集. C編 (ISSN:18848354)

巻号頁・発行日

vol.78, no.786, pp.523-534, 2012

被引用文献数

4

著者

日本機械学会 [編]

出版者

日本機械学会

巻号頁・発行日

1941

著者

阿部 豊 新井 崇洋

出版者

日本機械学会

雑誌

日本機械学會論文集. B編 = Transactions of the Japan Society of Mechanical Engineers. B (ISSN:03875016)

巻号頁・発行日

vol.71, no.702, pp.658-665, 2005-02-25

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Spontaneous vapor explosion can occur when a layer of the high temperature molten material lies on the water pool or on the moisture floor. This is so-called base-triggered vapor explosion. The base-triggered vapor explosion is supposed to occur in the case of a severe accident in various industrial facilities. It is very important to clarify the occurrence condition and possibility of the base-triggered vapor explosion from the viewpoints of the prediction and the prevention of the vapor explosion. In order to evaluate the occurrence conditions and to clarify the micro-mechanism of the base-triggered vapor explosion, the experimental apparatus to observe the base-triggered vapor explosion from the bottom of the floor to above is designed and constructed. The experiments using U-Alloy95 as a simulant material are conducted. Consequently, the microscopic behavior at the interface between the molten material and water can be observed in detail with this experimental apparatus. The interfacial behavior of the molten material is quantitatively evaluated by the PIV analysis and the digital auto-colrrelation method with the experimental results. The blowout velocity of the molten material at vapor explosion is evaluated from the visual data obtained on the experiment. The generated pressure at the vapor explosion is estimated by using the blowout velocity. In addition, occurrence condition of the base-triggered vapor explosion is evaluated with the thermal interaction zone (TIZ) theory.

著者

井坂 秀治 西田 公至 齋當 建一

出版者

日本機械学会

雑誌

日本機械学会論文集. C編 (ISSN:03875024)

巻号頁・発行日

vol.66, no.645, pp.1502-1508, 2000-05 (Released:2016-02-15)

被引用文献数

1

---

The purpose of the present investigation is to design an adaptive noise control muffler which has the most suitable location of secondary source. In the experiment, the distribution of sound pressure level in the muffler model has been measured by a sound visualization technique in order to obtain the maximum sound reduction by the minimum secondary sound under active control. The experimental results show that the target frequency could well be attenuated when the distance between the primary source and the secondary source is equal to the length eguivalent to one-half of the wave length of a target sound or its integral multiples.

著者

藤田 喜久雄 赤木 新介 廣川 敬康

出版者

日本機械学会

雑誌

日本機械学会論文集 C編 (ISSN:03875024)

巻号頁・発行日

vol.59, no.564, pp.2576-2583, 1993-08

著者

辻 義之 宮地 圭 鈴木 孝裕 中村 育雄

出版者

日本機械学会

雑誌

日本機械学會論文集. B編 = Transactions of the Japan Society of Mechanical Engineers. B (ISSN:03875016)

巻号頁・発行日

vol.70, no.695, pp.1679-1686, 2004-07-25

参考文献数

17

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In a zero-pressure gradient turbulent boundary layer, the multi-point measurement by 24 ch I-probes is performed. The relation between coherent structures and logarithmic velocity profile is studied by way of proper orthogonal decomposition technique and the stochastic estimation. It is found that the existence of coherent structures are necessary condition for the universal velocity profile, however it is not enough. Small-scale motions are also necessary to realize the log-law profile. The probability density profile in the overlap region is studied, and as a result, the invariant assumption of PDF in relation to the coherent structure is obtained. It was also evaluated how the velocity fluctuation in the log-region is affected by the coherent structures.

出版者

日本機械学会

巻号頁・発行日

2001

著者

田中 真美 長南 征二 江 鐘偉 中島 英貴

出版者

日本機械学会

雑誌

日本機械学会論文集. C編 (ISSN:03875024)

巻号頁・発行日

vol.65, no.631, pp.970-976, 1999-03

被引用文献数

4

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This paper is a study on the valuation and mathematical formulation of human touch sensation. First, the feelings of touch are collected on five natural and chemical fabrics through the SD (Semantic Differential) method questionnaires sent to twenty three examinees. The feelings are valued on each fabric by using the weigthed mean on graded factor feelings. The multiple regression analysis is then introduced to represent the overall evaluation of touch on every fabric by a linear function of the valuations on feelings of touch. Next, a soft tactile sensor made of a PVDF (Polyvinylidene Fluoride) film patch and rubber layers is assembled and slid over the same sample fabrics to collect the surface tactile information on the fabrics. The features on the collected data are then extracted by calculating the temporal average of absolute out signal and using the intensity of power spectral density on the medium frequency range. Comparison of the results show that the PVDF sensor well describes the tactile perception of forefingers.

著者

前田 太佳夫 鎌田 泰成 酒井 雄作 高原 直樹

出版者

日本機械学会

雑誌

日本機械学會論文集. B編 = Transactions of the Japan Society of Mechanical Engineers. B (ISSN:03875016)

巻号頁・発行日

vol.71, no.701, pp.171-176, 2005-01-25

参考文献数

5

被引用文献数

5

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This paper describes the measurement of the flow field around rotor blade. Three-bladed upwind rotor was tested in an open jet type wind tunnel. The rotor has a diameter of 2.4m. Flow field around rotor blade was measured with the use of two-dimensional LDV. The flow field was measured in x-y plane and z-y plane. The circulation around the blade sections were calculated by flow vectors around the rotor blade. The velocity vectors at optimum operation show a smooth flow around the blade and the bound vortex around blade cross-section seems to be persistent. On the other hand, the velocity vectors at stall condition demonstrate significant fluctuations in the near wake and separation on the blade suction side was observed. The circulation around blade span-wise section was calculated at the certain control volume. By the observation of flow field and calculated results of circulation, it seems that the flow is separated at the blade from middle-span region to tip region at stall condition. No separation was observed at the blade root region.