著者

松浦 元樹 田川 彰男 小川 幸春 Akio Tagawa 小川 幸春 Yukiharu Ogawa

出版者

千葉大学大学院園芸学研究科

雑誌

食と緑の科学 (ISSN:18808824)

巻号頁・発行日

no.65, pp.55-59, 2011-03

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Young's modulus and Poisson's ratio, which characterized elastic properties of a material, were measured bymeans of compress utensil and digital images captured by digital camera, and the elastic values were evaluated. Atissue of boiled Japanese radish and carrot root, which is too fragile to measure their Poisson's ratio by traditionalmethods, was used as sample materials. Cylindrical samples were cut out of the tissue using a precise apparatusand their dimensions were set to 15mm height and 30mm diameter. The samples were then compressed. The stressof the samples against compression was measured using a creep meter. The compressed deformation of the sampleswas captured by a digital camera and accurately analyzed by high resolution digital images. The Poisson's ratio wascalculated from differences in the sample deformation in digital images. A Young's modulus was also calculatedfrom the compressed deformation and the stress. As a result, the Poisson's ratio of boiled Japanese radish wasfound to be constant or slightly decrease with boiling elapsed time. The Poisson's ratio of carrot also decreasedwith boiling, and its value was smaller than the Japanese radish's. On the other hand, the Young's modulus for eachsample decreased sharply when boiling started but after 4 minutes boiling it was stabilized at low values.