著者

阿部 憲義 高曽 徹 隈 裕二

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会九州支部講演論文集 2004.57 (ISSN:24242780)

巻号頁・発行日

pp.305-306, 2004-03-19 (Released:2017-06-19)

著者

武田 克彦 武田 秀幸 森谷 信次 棚澤 一郎

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.70, no.689, pp.279-285, 2004-01-25 (Released:2011-03-03)

参考文献数

7

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A feasibility study was made on the application of the waste edible oil-ethyl ester fuel to diesel engines. The waste edible oil methyl ester fuel is known as the fuel which emits clean exhaust gas. however, the waste edible oil ethyl ester fuel has not been investigated elsewhere. We prepared the waste edible oil ethyl ester fuel, and tried to apply it to diesel engines. In the experiment described in this paper, the waste edible oil-ethyl ester fuels with 30, 35 and 40% in weight of the ethyl alcohol were prepared in order to decide the amount of the alcohol. The lower calorific value, density, surface tension and kinematic viscosity of the waste edible oil-ethyl ester fuels were measured. It was found that the thermophysical properties of the waste edible oil-ethyl ester fuels are lower than the waste edible oil. In addition, the ignition temperature and the ignition time were measured and found that the ignitionability was improved by the esterification and all ethyl ester fuels are almost the same. Finally the waste edible oil-ethyl ester fuel was burned in a conventional 273-cc diesel engine. Although the specific fuel consumption was a little higher, the smoke scale and NOx in the exhaust gas were lower than the gas oil. Especially, the smoke scale of EE40 (made from 40% in weight of the ethyl alcohol) was reduced drastically, and it was less than half of the gas oil.

著者

藤田 健

出版者

一般社団法人 日本機械学会

雑誌

流体工学部門講演会講演論文集 2009 (ISSN:24242896)

巻号頁・発行日

pp.3, 2009-11-06 (Released:2017-06-19)

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R&D study of Mitsubishi Regional Jet (MRJ) has been conducted since 2003, under the auspice from NEDO. In this study, various fundamental research items for aircraft development including advanced aerodynamics, noise study and multidisciplinary design optimization (MDO) have applied to the design of MRJ. In these R&D activities, state-of-the-art technology developments have been pursued by strong university-government-industry cooperation. This report presents application of CFD and MDO technologies to MRJ design as an example of R&D activities.

著者

大塚 敏之 石谷 雅宏

出版者

一般社団法人 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.652, pp.3962-3969, 2000-12-25 (Released:2008-02-26)

参考文献数

9

被引用文献数

1

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This study applies differential game theory to simplified four-wheeled vehicle models. We describe the motions of two four-wheeled vehicles on plane as nonlinear systems and formulate receding-horizon differential game problems. Performance indexes of the differential games have a moving performance interval. The game optimal solution (minimax solution) is calculated by applying a real-time algorithm without successive approximation. Numerical results of pursuit-evasion and overtaking are reported and discussed.

著者

浅見 優之介 伊藤 弘大 堀江 亮太 多田 充徳

出版者

一般社団法人 日本機械学会

雑誌

ロボティクス・メカトロニクス講演会講演概要集 2021 (ISSN:24243124)

巻号頁・発行日

pp.2P1-L01, 2021 (Released:2021-12-25)

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In this study, we developed an EEG-based MR game based on the hypothesis that games can be made more interesting by reflecting the psychological state read from the EEG. The genre of the game was shooting. We designed the game in such a way that the size of the aim in the game is linked to the EEG feature value, and that focusing increases the EEG feature value and shrinking the aim increases the hit rate. The β/α ratio was used as the EEG feature, and we sought an effective way to introduce the β/α ratio into the game. By setting a threshold value using the average value of the β/α ratio of the subjects, and by performing a moving average process that divided the values above and below the threshold value, we were able to manipulate the size of the aim as desired with a probability of about 80%.

著者

高見 創

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.86, no.881, pp.19-00295, 2020 (Released:2020-01-25)

参考文献数

16

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To shorten the stopping distance of the high-speed trains in case of emergency such as a huge earthquake, the author developed the small-size and light-weight aerodynamic braking device. The device increases an aerodynamic drag force of a train to achieve a high deceleration at the range of over 350 km/h without a friction between rail and wheel. The device is as miniaturized as possible in order to be installed flexibly on the train, whereby many devices with small-size drag panels are appropriately arranged throughout the train roof to obtain higher drag force. A pair of drag panels rotating around a horizontal axis which are connected by the gear can be actuated by the traveling wind without a large-size actuator. The full-scale prototype aerodynamic braking device is designed and manufactured. To examine its aerodynamic characteristics, one or two prototypes are tested on a wind tunnel facility at a maximum flow speed of 400 km/h (111 m/s). It was proven that the response time of motion from the folding position to the braking position took only 0.39 s, and the device could produce the aerodynamic drag of 2.3 kN per one unit at 400 km/h. Detached-eddy simulation (DES) is used to study the flow around a train roof with a large number of devices. The rate of change of the drag coefficient for devices with the staggered arrangement which aims to improve a total drag force of a train is compared against the standard parallel arrangement at U = 360 km/h. The staggered arrangement could increase the total drag coefficients 10.3 percent as compared to the standard parallel arrangement.

著者

下野 智史 児玉 斎 鈴木 克幸

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

pp.15-00294, (Released:2016-01-22)

参考文献数

13

被引用文献数

2 1

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Taylor-made designs are required for golf clubs, in particularly for golf shafts, because the golf equipment have great effects on the performances of players. Our objective is to establish an optimal design method of golf shafts for each player depending on their swing motions. We measured the swing motions with a 6-axis sensor that inserted into the grip end not to prevent normal motions. We analyzed the head motions at the impact using FEM with the swing data, and we tried to figure out the best shaft spec for an optimal impact. The optimization algorithm was followed 4 skilled shaft designers, which means that we had optimized the 4 SPECs in turn as below; 1) Weight, 2) Torque, 3) Flex, 4) EI pattern. As a result, the distance of a subject, a female professional golfer of JLPGA, was improved 11yrd more with the optimized shaft, and she uses the optimized shaft for more than 2 years. Thus our method was proven to be efficacious for some typical players. On the other hand, we were not able to get desired results for another 2 subjects. We believe the causes of undesired results are that some players change their swing motions depending on the shaft spec. We ought to consider the motion adjustment depending on the shaft spec in order to design optimal golf shafts for each player in the near future.

著者

中島 知浩 伊藤 慎一郎 平塚 将起

出版者

一般社団法人 日本機械学会

雑誌

シンポジウム: スポーツ・アンド・ヒューマン・ダイナミクス講演論文集 2017 (ISSN:24329509)

巻号頁・発行日

pp.B-12, 2017 (Released:2018-05-25)

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The structure of the current tennis ball is covered with a uniform felt fabric on the outer surface made of hard rubber. The inside of the ball is filled with air about 1.8 atm. The seam is filled with adhesive or resin. The seams are filled with glue or resin. The ball in tennis is always struck with rotation. Rotational speed of the serve ball is about 5,500 rpm maximum. It is up to about 4,700 rpm for the stroke. As the ball continues to hit, the surface felt wears. Also, air leaks out through the structure inside. These factors cause a difference in the aerodynamic characteristics of new and used balls.In general it is a new ball to use in the game, but the one used in practice is a used ball. Worn out changes the hydrodynamic properties of the ball, and the trajectory of the ball also changes. Therefore, the performance difference between the new tennis ball and the used tennis ball should be confirmed by measuring the fluid force.In this research, the aerodynamic characteristics of the old and new tennis balls rotating were investigated and the PIV results of the flow around the ball due to the wear of the felt producing these characteristics. For the four types of tennis balls tested, used balls showed higher in drag coefficient than new balls, and new balls tended to be higher than used ball in lift coefficient. It is believed that deformation due to deterioration of ball rubber brings about a change in drag coefficient, which causes a change in lift coefficient due to wear of the surface felt. In the new ball, feltfluff stands, which indicates that the wake flow is large and inclined diagonally backward compared to the used ball, and the air around the ball is found to be caught by the felt fluff.

著者

長谷川 益己 佐々木 康寿

出版者

一般社団法人 日本機械学会

雑誌

材料力学部門講演会講演論文集 2001 (ISSN:24331287)

巻号頁・発行日

pp.351-352, 2001-07-19 (Released:2017-08-01)

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Changes in shear wave velocity were measured by the sing-around method rotating the oscillation direction of the wave with respect to the orthotropic axis of wood. The velocity of the shear wave propagated through the stressed wood decreased suddenly when the oscillation direction coincided with the tangential direction of the wood. The polarization direction of shear wave coincided with the principal axes of wood, not with the direction of the principal stresses. This finding indicated that the polarization direction was much affected by the texture-induced anisotropy of wood. Based on the result, the bending and shear stress distributions in wood beam specimen were estimated by the acoustoelastic birefringent method. The stress values estimated agreed well with those obtained by the strain-gauge method and mechanical calculations.

著者

高岸 佐代 高橋 知宏 段 智久 千田 二郎 藤本 元

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.65, no.631, pp.1128-1133, 1999-03-25 (Released:2008-03-28)

参考文献数

9

被引用文献数

2 1

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The characteristics of combustion process in internal combustion engines are affected by mixing process between the injected fuel and the ambient gas. Therefore, it is necessary to understand the flow field in diesel fuel sprays. In this study, a single spray was injected into a quiescent atmosphere with room temperature at high pressure through a single hole nozzle for simplification. To discuss the flow field in diesel sprays, structure of the spray was visualized by laser light sheet method. And, it was revealed that the vortex structure inside the spray affects the classification of droplet particles by taking microscopic photographs of the droplets with high resolution film. And applying PIV method into the spray photography, both the formation of meandering structure of the spray mainstream and the ambient gas entrainment process are clarified.

著者

段 智久 高岸 佐代 大石 直己 千田 二郎 藤本 元

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.62, no.597, pp.2079-2085, 1996-05-25 (Released:2008-03-28)

参考文献数

15

被引用文献数

7 8

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In the experiments presented here, a single diesel spray of n-tridecane was injected for a certain duration through a hole-type nozzle (ln/dn=1.1mm / 0.2mm) into a quiescent high pressure atmosphere at room temperature. We used the same amounts of fuel injection for each injection pressure and the same ambient gas density field for all injection experiments including tests of the effect of changing the ambient gas. The macroscopic spray structures were observed by instantaneous photography and using a high-speed video camera system. Furthermore, the microscopic structure was observed by means of laser light-scattering photography, fuel droplet distribution was measured using the laser light-sheet of a pulsed Nd-YAG laser, and the mean diameter of the drop was obtained through image processing by the laser extinction method. This study revealed that the diesel spray consisted of a number of large vortices, which was considered to be the coherent structure. With high ambient gas viscosity, the fuel droplet became smaller. It was also found that a large vortex existed at the tip of the spray.

著者

段 智久 高岸 佐代 大石 直己 千田 二郎 藤本 元

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.62, no.599, pp.2867-2873, 1996-07-25 (Released:2008-03-28)

参考文献数

14

被引用文献数

2 5

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This study deals with the effect of the viscosity of the ambient gas on the atomization process of a diesel spray. The liquid fuel is injected through a single-hole nozzle (ln/dn=0.75 mm/0.25 mm)with the injection differential pressure of 16.2 MPa inside a constant-volume vessel under a high-pressure field at room temperature. In practical combustion chambers of diesel engines, the viscosity of the ambient gas varies mainly with its temperature. In this experiment, various gases (CO2, N2, Ar, Ne, and Ar+Ne) were utilized for the ambient atmosphere in order to change the ambient gas viscosity. The vaporization of fuel drops was negligible. This study, revealed that the higher the viscosity, the more the spray spreads in the radial direction, thus the spray angle increased and tip penetration decreased. The droplets became smaller and were distributed in the inner region of the cold-state diesel spray under high ambient viscosity conditions. Further more, it was found that processes of ligament formation in the liquid jet and initial atomization were affected by kinematic viscosity ratio between the liquid fuel and ambient gas, and the spray dispersion and mixing process in the downstream region was affected only by the ambient gas kinematic viscosity.

著者

福島 忠栄

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会誌 (ISSN:24242675)

巻号頁・発行日

vol.91, no.838, pp.962-966, 1988-09-05 (Released:2017-06-21)

著者

井門 敦志 小濱 泰昭

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.71, no.703, pp.817-824, 2005-03-25 (Released:2011-03-03)

参考文献数

8

被引用文献数

4 4

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As a train runs at higher speeds, the aerodynamic drag increases. On long train-sets such as those of Shinkansen, the aerodynamic drag is mainly generated by intermediate vehicles. In previous researches, we proved that smoothing the under-floor surface reduces the aerodynamic drag. To investigate the mechanism of this effect, we performed wind tunnel tests with train models consisted of three vehicles, each representing a head, intermediate and tail vehicle, and measured the aerodynamic drag and pressure distributions on the intermediate vehicle. We divided the aerodynamic drag of the intermediate vehicle into the components at different parts of the carbody and clarified the effect of smoothing the under-floor surface to decrease the aerodynamic drag.

著者

井門 敦志

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.69, no.685, pp.2037-2043, 2003-09-25 (Released:2008-03-28)

参考文献数

8

被引用文献数

1 1

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In our previous researches, we estimated the reduced quantity of aerodynamic drag of trains by smoothing under-floor construction. However, we did not compare the results of wind tunnel tests with those of on-track tests, or verify the accuracy of wind tunnel tests for the aerodynamic drag of trains. In this research, we estimated the aerodynamic drag of a train-set by wind tunnel tests. Regarding the reduced quantity of the aerodynamic drag of trains, we compared the results of wind tunnel tests with those of on-track tests. These test results show that the reduced quantity of the aerodynamic drag of trains by wind tunnel tests approximately agrees with that by on-track tests.

著者

吉村 充孝

出版者

一般社団法人 日本機械学会

雑誌

日本機械学會論文集 (ISSN:00290270)

巻号頁・発行日

vol.42, no.363, pp.3428-3437, 1976-11-25 (Released:2008-03-28)

参考文献数

5

被引用文献数

1 1

著者

小林 英男

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会誌 (ISSN:24242675)

巻号頁・発行日

vol.73, no.619, pp.1192, 1970-08-05 (Released:2017-06-21)

著者

吉田 博夫

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会誌 (ISSN:24242675)

巻号頁・発行日

vol.111, no.1072, pp.162-163, 2008-03-05 (Released:2017-06-21)

参考文献数

3

被引用文献数

1 1

著者

伊藤 史斗 内田 和男 長谷 和徳

出版者

一般社団法人 日本機械学会

雑誌

シンポジウム: スポーツ・アンド・ヒューマン・ダイナミクス講演論文集 2017 (ISSN:24329509)

巻号頁・発行日

pp.A-9, 2017 (Released:2018-05-25)

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There are many studies for bicycles and pedaling; however, most of the pedaling studies are conducted based on experiments, such as inverse dynamics method. The purpose of this study is to develop a forward dynamics model of pedaling to generate pedaling motion on computer without experimental data. The proposed model was used proportional-derivative (PD) control for joint driving torque and the referred joint angles were optimized by genetic algorithms. Cost function of optimization was defined as minimum of the muscle load and differences between the objective crank angular velocity and that of the simulation. Joint torques and pedal forces was obtained from the simulation and was compared with the actual experimental data. Simulation results were tended to vibrate compared with the actual experimental data. In addition, magnitude of the cost function was investigated when changing saddle height as 0.700, 0.725, 0.750, 0.775 and 0.800 [m]. As a result, the cost function decreased as the saddle height became higher, and the cos function was minimum when the saddle height was 0.775[m].

著者

岡村 宏 大石 久己 土屋 賢康 長谷川 浩志

出版者

一般社団法人 日本機械学会

雑誌

Dynamics & Design Conference 2016 (ISSN:24242993)

巻号頁・発行日

pp.339, 2016 (Released:2017-06-19)

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We report the result of test that has given the acoustic excitation to the new guitar in the aging cell with using the Bach's cello suites. The sound quality effect of playing the guitar for five years is the same as one of the four weeks aging test with the high load. However, the too much aging gives the new guitar the adverse effects. In this time, we were able to have the good balance results with the light load aging. But there were few effects in the upper position sounds of the guitar. The sound range of the cello is not enough to the acoustic excitation of high frequency zone. So, we will try soon the aging test with playing the violin pieces.