著者

下代 昇平 谷本 道哉

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.18, no.3, pp.184-191, 2018-10-11 (Released:2018-10-12)

参考文献数

31

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Recently, athletes tend to focus on trunk stability during sports movements. Trunk stability is thought to play the role of an upper and lower limbs' foundation and to improve transfer capacity of power from the lower limbs to the upper limbs. Intra-abdominal pressure (IAP) development is considered to be important for trunk stability training exercises such as planks. The purpose of this study was to examine how IAP changed in sports movements and to compare IAP during various types of movements. Ten healthy men with resistance training experience of more than 1 year performed movements. Maximal IAP during the valsalva maneuver (maxIAP) was measured. The subjects performed trunk stability training (TST), trunk muscles resistance training (TRT), upper and lower limbs movement muscles resistance training (LRT) and dynamic sports movement (DSM). IAP value during TST (8~19%maxIAP) was significantly lower than that during DSM and LRT and was almost the same as that during TRT. IAP value during DSM was the highest (37~62%maxIAP) in all movement groups. IAP value correlated at erector spinae muscles electromyography (EMG) during TRT, LRT and DSM (P<0.05). These results suggest that IAP development did not appear during TST. IAP development may be related to trunk extension moment.

著者

西原 一嘉 Knisely Charles W. 中畑 佑介 井口 学

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.8, no.3, pp.189-195, 2008-09-25 (Released:2009-03-25)

参考文献数

37

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Experimental Investigation has been carried out on turbulent flow around an obstacle placed on the lower wall of a square duct. Particular emphasis is placed on the velocity distribution of turbulent flow, the reattachment length, and the static pressure distribution on the upper wall of the duct. Two types of obstacles are used: a backward-facing step and a diffuser-like constriction. A flow visualization method is used for measuring the velocity distribution and reattachment length. Soap bubbles are used as the tracer. A pressure transducer is used for measuring the static pressure distribution. A blockage factor is introduced to correlate the static pressure distribution. The reattachment length depends strongly on the shape and size of an obstacle. An empirical equation is proposed for the reattachment length.

著者

松岡 常吉 中村 祐二

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.20, no.4, pp.229-236, 2021-01-07 (Released:2021-01-14)

参考文献数

12

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Scale modeling based on static and dynamic similarity has been widely used with high-speed photography techniques for motion pictures to reproduce unrealistic world. Focusing on video works created by SFX as examples of scale modeling experiments, this paper attempts to explain the scale modeling theory, so called “Law approach” which is a method to derive the scaling law based on deep physical insights. To accomplish this, the falling motion of an object in fluid is taken up as the simplest but frequent case. The governing equation of the phenomenon is considered, and the magnitude of each term is estimated. A quantitative comparison demonstrates which factor is most significant in that phenomenon. Though it seems a relatively complicated explanation, it is believed that this approach gives a clear insight into how the dominant factor(s) is extracted in the Law approach.

著者

小倉 崇生 戸田 均 木村 巧 松井 応式 伊藤 安海 根本 哲也

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.11, no.1, pp.18-21, 2011-03-25 (Released:2011-09-25)

参考文献数

14

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It is necessary to estimate the impact force received by the human body for the purpose of accident prevention, accident analysis and criminal investigations against contact of Machine and structure, fall, overturn and brutal blows of blunt instruments. In this study, we showed the performance of subcutaneous fat and muscle buffering by measuring the impact force to the pork. As a result, the following findings were obtained. 1) For estimation of buffer property of muscle and fat tissue of human to impact force, it is possible to substitute pork. 2) Skin is poorer on buffer property than muscle and fat tissue. 3) The magnitude of the impact force transmitted to the bone rises in proportion to a rise in impact velocity, and is estimated to be at least ten times the weight of impactor. 4) Exist as complex of skin, muscle and fat tissue, the impact force transmitted to the bone is not less than one-tenth compared with only skin.

著者

大賀 智史 濱崎 仁 淡中 菜央

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.21, no.2, pp.104-109, 2021-07-03 (Released:2021-09-09)

参考文献数

6

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This study proposes the method for estimating the amount of corrosion of rebar in concrete from the surface shape measurement of reinforced concrete by using a 3D scanner. We focused on the surface swelling caused by the corrosion of the rebar in concrete, and found the relationship between the change in surface shape and the amount of corrosion of the rebar. As a result, we confirmed that corrosion could not be visually confirmed by 3D measurement, and showed the possibility that amount of corrosion of rebar could be estimated from the amount of surface swelling. We also confirmed that these relationships differ depending on the corrosive environment.

著者

松岡 常吉 中村 祐二

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.20, no.4, pp.229-236, 2021

---

<p> Scale modeling based on static and dynamic similarity has been widely used with high-speed photography techniques for motion pictures to reproduce unrealistic world. Focusing on video works created by SFX as examples of scale modeling experiments, this paper attempts to explain the scale modeling theory, so called "Law approach" which is a method to derive the scaling law based on deep physical insights. To accomplish this, the falling motion of an object in fluid is taken up as the simplest but frequent case. The governing equation of the phenomenon is considered, and the magnitude of each term is estimated. A quantitative comparison demonstrates which factor is most significant in that phenomenon. Though it seems a relatively complicated explanation, it is believed that this approach gives a clear insight into how the dominant factor(s) is extracted in the Law approach.</p>

著者

金子 弘 格内 敏 田路 秀樹 西村 淳

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.11, no.3, pp.182-187, 2011-09-28 (Released:2012-03-28)

参考文献数

12

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The effect of the visual correction with glasses on the brain activation by reading sentences with characters presented in a stimulus image were measured by the fMRI. In order to move the lens unit inside the fMRI equipment, we choose the suitable materials for the lens holder and jigs. As the results, when stimulus images can be seen clearly, the brain activations are found in the classical language areas. On the other hand, when the visual correction was clear but the target images were blurred, or when the target images were clear but the correction was not sufficient, little activation was found in those areas, although lower visual areas and the frontal eye field / premotor area were activated. The activations in the classical language areas would be much sensitive to whether the character images are readable or not.

著者

坂井 建宣 柴山 正輝 野方 文雄 蔭山 健介

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.17, no.1, pp.39-44, 2017-04-12 (Released:2017-04-12)

参考文献数

13

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Multichannel heart motion sensors using flexible circuits were fabricated for the monitoring the heart motion in the heart diseases. In this study, the PVDF sensors were used as the heart motion sensors. These sensors were modified with the air gap and the protection sheet, and the sensors with the flattest frequency response were selected. These selected modified sensors were preliminary used in a 4-channel sensor array in order to check whether the heart sounds were detected, and they precisely detected the motion of S1 and S2. Furthermore, 80 sensors were used for the multichannel sensor array using the flexible printed circuits. By using this 80-channel sensors array, the vibrations of the chest surface were measured and analyzed. As a result, this multichannel sensor array could measure the heart sound and detected a sound distribution of the chest surface. It was concluded that our developed measurement system could be applied to inspect heart diseases employing a digital database management of the auscultation examination.

著者

南川 久人 藤原 海 栗本 遼 安田 孝宏 原田 英美子 畑 直樹

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.16, no.1, pp.77-83, 2016-04-11 (Released:2016-04-11)

参考文献数

17

被引用文献数

1

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Effects of microbubbles on germination and growth in deep flow technique of spinach (Spinacia oleracea) were investigated. In the germination experiment, four experiment plots; (1) underwater germination with microbubble water plot (MB plot), (2) underwater germination with aerated water plot (Aeration plot), (3) underwater germination with water plot (Water plot), (4) germination on wet cotton plot (Control plot), were used. Two hundred individuals were germinated for each plot. Germination rate of MB plot after 7 days was about twice as high as that of Aeration plot and Control plot. In the growth experiment, three experiment plots; (1) tenth solution concentration water with microbubble plot (MB plot), (2) tenth solution concentration water plot (Aeration plot), (3) full solution concentration water plot (Control plot), were used. Twelve individuals were grown for each plot. Leaves weight of MB plot was as much as that of Control plot. In contrast, plant physiological disorders appeared in all plants of Aeration plot. Multi-element determination revealed that K concentration of Aeration plot was lower than that of the others plots. These results indicate that microbubbles contribute to the plants absorbing the nutrient from roots.

著者

坂本 潤嗣 藤井 雅留太 中村 正行

出版者

The Japanese Society for Experimental Mechanics

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.14, no.4, pp.257-263, 2014-12-28 (Released:2014-12-28)

参考文献数

21

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This paper presents a new and convenient process for determining the material plasticity parameters of metal materials through an indentation test conducted using a Rockwell testing machine and FE analysis. Identified parameters almost coincide with practical values. The proposed method can be used to evaluate the characteristics of materials on the order of micro to millimeters. First, the P-h curves of the indentation are determined by experiment. Second, FE analysis of the indentation test assuming plastic hardening behavior in power-law hardening material is specified by the stress-strain curve. The FE model consisted of the test piece material and the indenter with a spring element considered the elastic deformation of the measuring system. The material parameters can be identified based on the curve fit using the polynomial function consisting of material parameters. The best solution is determined by using the response surface methodology. For identification example using steel and cupper alloy, the estimation of the plastic and elastic properties are possible for practical use.

著者

小島 朋久 歌川 和宏 納冨 充雄

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.18, no.2, pp.103-109, 2018-07-23 (Released:2018-07-24)

参考文献数

16

被引用文献数

2

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The impact resistance improvement is important for glass members which are functional material in optics. It was reported that sticking a thin polymeric film on the glass plate is an effective way to easily reinforce the glass plates against impact loads. However, the reinforcing effect is not enough evaluated quantitatively. In this paper, impact fracture behavior was investigated with a glass plate stuck with thin polymeric film. An impact experiment was conducted using drop weight with a steel bar for the incidence of the impact load to a glass plate. In the experimental result of glass plate without film, stuck with film (3.2% thickness of the glass plate) and tempered glass plate, it was revealed the toughness for the fracture initiation was 12% improved by film sticking. Moreover, it was implied the fracture strength is not necessarily in proportion to the decrease of kinetic energy of the colliding object after fracture since it was largest with film stuck glass plate, nevertheless, the fracture strength was highest with a tempered glass plate. Furthermore, a proposal was made for the further improvement of the impact resistance by sticking thin film based on the investigation of the fracture mode of the glass plate.

著者

阪上 隆英 久保 司郎 原 文人 番匠谷 隆

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.1, no.1, pp.34-38, 2001 (Released:2010-03-19)

参考文献数

5

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Thermographic NDT technique using an active thermal stimulation method was applied for the detection of delamination defects in concrete structures. An oil heater, which can apply heat flux to the objective body by radiation and convection heat transfer, was employed for active heating. Evaporation cooling by water spray was used for active cooling. Preliminary experimental investigations were carried out for concrete specimens with artificial delamination defects. It was found that delamination defects can be detected from the thermal images, in which localized high or low temperature regions appeared above the delamination defects. Proposed technique was applied for the inspection of actual delamination defects in the concrete railway bridges. It was found that the defect shape was clearly estimated from the localized temperature region appeared in thermal images under active thermal stimulation.

著者

高 岡 大 造

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.21, no.1, pp.57-59, 2021-04-10 (Released:2021-05-02)

参考文献数

10

著者

Kenji KATOH Tatsuro WAKIMOTO

出版者

The Japanese Society for Experimental Mechanics

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.14, no.Special_Issue, pp.s36-s41, 2014-07-01 (Released:2014-09-03)

参考文献数

10

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It is well known as the wringing phenomenon of gage blocks that a strong adhesive force appears between two smooth surfaces when a thin liquid film is applied on the interface. A theoretical and experimental study is conducted to discuss the wringing mechanism. The liquid film may be separated into a large number of small puddles when two surfaces are rubbed together. One can expect a large adhesive force due to the resultant of surface tension acting on the circumference of each puddle. Numerical results for oil distribution between two surfaces show that the total perimeter length of liquid film reaches 10500 m on the surface of 3cm2, which leads to 1.0×106 (N/m2) for the adhesive force. The adhesive forces measured experimentally roughly agree with the theoretical value. A simple model is proposed to explain the adhesive force dependence on the velocity of pulling apart two surfaces.

著者

森 幸治 藤川 祐介 松原 裕樹 堀口 佑樹

出版者

The Japanese Society for Experimental Mechanics

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.13, no.4, pp.360-365, 2013-12-28 (Released:2014-03-28)

参考文献数

3

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In order to produce bio-diesel fuel (BDF) effectively from triglyceride contained in coffee grounds, the solid catalyst method using calcium oxide was examined. Since commercially available calcium oxide has low catalytic activity, a method of converting the calcium oxide to calcium methoxide and/or calcium glyceroxide before esterification was tested. The method was applied to generate the BDF from unused canola oil. The produced liquid was analyzed both chemically and by the NMR, and it was revealed that the liquid was able to be called as BDF and esterification rate was about 80%. Extraction of triglyceride from waste coffee grounds was tried using hexane as a solvent, and 780 mL of triglyceride-rich oil was extracted from 8 kg of the waste coffee grounds. The oil was subjected to the BDF production using the calcium oxide and the BDF was produced at the esterification rate of about 75%. The coffee grounds after the extraction of the triglyceride-rich oil were applied to deodorants and solid fuels. The experimental results showed that the coffee grounds decreased the smell of cigarettes. Furthermore, it was also found that the coffee grounds were easily ignited and burned by adding some sawdust and wax to the coffee grounds.

著者

森田 康之 石黒 孝知 巨 陽

出版者

The Japanese Society for Experimental Mechanics

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.13, no.1, pp.88-92, 2013-03-28 (Released:2013-09-28)

参考文献数

20

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High-efficiency technology to the photodiodes has become a critical issue. Surface plasmon resonance (SPR) would be one of the means for solving the problem. Photocurrent of photodiodes is enhanced by metal nanoparticles, which induce the localized SPR, deposited on light-receiving surface of the photodiodes. Most previous studies had been focused on the photocurrent enhancement effect around maximum absorption wavelength of the nanoparticles. The effect except the wavelength has not been paid attention yet. For instance, in case of a solar cell, metal nanoparticles which have maximum absorption wavelength at around 500nm, have been widely employed since solar light has higher illuminance around 500nm. However, the photocurrent enhancement effect of the nanoparticles has not studied around near-infrared light though illuminance of the near-infrared light is quite valuable. Therefore, in this study, experimental investigation of photocurrent enhancement effect was conducted using Au nanoparticles with 100 and 150nm in nominal diameters, which have maximum absorption wavelengths at around 500nm. As a result, the photocurrent enhancement effect was obtained at near-infrared wavelengths. In addition, higher enhancement effect was achieved when the two Au nanoparticles were mixed. This would be ascribable to obtaining wider bandwidth of maximum absorption wavelengths due to mixing of different-size nanoparticles.

著者

岩佐 貴史 原田 卓

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.16, no.3, pp.221-225, 2016

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<p> A performance of the feature-point matching using a concave target marker is investigated for three dimensional (3D) surface shape data given by a grating projection method. Multiple corresponding points are previously created from a surface shape measurement of the concave target markers, and a coordinate transformation matrix that serves as an interface between two sets of 3D shape measurement data is obtained from the feature-point matching with singular decomposition method. Then, effects of the number of the target marker on matching accuracy are discussed for the surface shape measurement data of the spherical mirror model. The results showed that the feature-point matching using the concave target marker connects two sets of the 3D surface shape measurement data at 40 μmRMS accuracy regardless of the number of the corresponding points. This matching accuracy is roughly the same as that achieved by the surface shape measurement using the grating projection method.</p>

著者

小笠原 永久 千葉 矩正 山田 浩之 Xi CHEN

出版者

The Japanese Society for Experimental Mechanics

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.12, no.1, pp.26-32, 2012-03-28 (Released:2012-09-28)

参考文献数

13

被引用文献数

1

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An identification method with a sharp indentation for elastoplastic properties of film/substrate system is proposed. The method is based on extensive finite element computation on "soft film on hard substrate" cases indented with a sharp indenter. The method utilizes the substrate effect on load versus displacement relation in the indentation; this effect has often been regarded as undesirable. The computational results are expressed as response surfaces in a material parameter space. Based on the surfaces, and employing experimentally obtained load versus displacement relation, the elastoplastic properties of the film are identified. To determine the elastoplastic properties more accurately, it is important to use not only the loading curve but also the unloading curve. Numerical examples determined by this method for film/substrate system are given.

著者

小川 欽也

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.2, no.2, pp.89-96, 2002 (Released:2010-03-19)

参考文献数

54

被引用文献数

5

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Split-Hopkinson Pressure Bar (SHPB) method is the most versatile technique to evaluate the stress-strain relations of materials at high rate of strain. Over the decades, the method has been improved and developed, and now, it has been widely applied to investigate the various kinds of mechanical properties of materials under impact loading. Recent research activities and techniques related to this famous method are reviewed in the present paper.

著者

相沢 亮汰 石井 慶子 麓 耕二

出版者

日本実験力学会

雑誌

実験力学 (ISSN:13464930)

巻号頁・発行日

vol.19, no.4, pp.281-286, 2020-01-20 (Released:2020-01-25)

参考文献数

11

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Heat transport devices using temperature-sensitive magnetic fluids are fast to start, have high heat transfer efficiency, and can be downsized. In addition, it has the advantage that it is not affected by the installation posture compared to conventional heat transport equipment. In order to apply a temperature-sensitive magnetic fluid to a heat transport device, it is necessary to clarify the heat flow characteristics of this fluid. However, since the ferromagnetic particles in the fluid are black and fine, observation with a microscope was difficult. In this study, the microcapsules contain a temperature-sensitive magnetic fluid, which enables fluorescence observation. Capsules were made by mixing a temperature-sensitive fluid, polymer, organic solvent, and fluorescent dye and dispersing in pure water mixed with a surfactant. Microcapsule aqueous solutions have been shown to have properties similar to magnetic fluids. When this solution was flowing, it was confirmed that when a magnetic field was applied, clusters were formed near the wall and a unique velocity distribution was formed. It was confirmed that as the solution temperature increased, the possibility of cluster formation decreased.