{"created":"2023-05-18T10:13:01.664774+00:00","id":5112,"links":{},"metadata":{"_buckets":{"deposit":"50268a77-37fa-4c1e-ad19-29cb66b11aa7"},"_deposit":{"created_by":5,"id":"5112","owners":[5],"pid":{"revision_id":0,"type":"depid","value":"5112"},"status":"published"},"_oai":{"id":"oai:yamanashi.repo.nii.ac.jp:00005112","sets":["63:132:514"]},"author_link":["357"],"item_2_alternative_title_1":{"attribute_name":"タイトル(別表記)","attribute_value_mlt":[{"subitem_alternative_title":"A review on physics of familiar geoscientific phenomena: Why are fine grains deposited slowly?","subitem_alternative_title_language":"en"}]},"item_2_biblio_info_7":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2022-02-21","bibliographicIssueDateType":"Issued"},"bibliographicPageEnd":"173","bibliographicPageStart":"159","bibliographicVolumeNumber":"32","bibliographic_titles":[{"bibliographic_title":"山梨大学教育学部紀要","bibliographic_titleLang":"ja"},{"bibliographic_title":"Bulletin of the Faculty of Education","bibliographic_titleLang":"en"}]}]},"item_2_creator_2":{"attribute_name":"著者名","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"福地, 龍郎","creatorNameLang":"ja"}]}]},"item_2_description_18":{"attribute_name":"フォーマット","attribute_value_mlt":[{"subitem_description":"application/pdf","subitem_description_language":"en","subitem_description_type":"Other"}]},"item_2_description_5":{"attribute_name":"内容","attribute_value_mlt":[{"subitem_description":"身近な地学現象である『なぜ細かい粒子はゆっくり堆積するのか？』を理解するためには，水や空気などの流体の中を落下する粒子に働く力として，重力と浮力の他に，粘性による抗力を考える必要がある。粒子を球体に近似できるとすれば，ストークスの法則により，粒子に働く抗力は，粒子の直径，粘性率及び落下速度に比例する。抗力は落下速度と共に増大し，これら３つの力が釣り合った時に落下速度は一定となり，粒子は一定速度のまま堆積する。この一定速度を終端速度と呼び，３つの力の釣り合いから求めることができる。粒子の終端速度は，粒径の２乗及び粒子と流体の密度差に比例し，粘性率に反比例する。従って，粒子の密度が同じであれば，細かい粒子ほど終端速度は小さくなり，ゆっくり堆積することになる。このことは，水中だけでなく空気中でも成り立つが，空気の粘性率は水の粘性率の約1/100 であるので，空気中では粘性の影響が現れにくい。落下させる物体のサイズを極端に違うものにするか，落下させる距離を極端に長くしなければ，終端速度に違いは出にくい。一方，風船が空気中を落下する場合には，風船のサイズが大きい程，風船の密度は空気の密度に近づき，空気との密度差がゼロに近づくために終端速度は小さくなり，ゆっくり落下する。風船の場合，終端速度に与える効果は，サイズよりも空気との密度差の方がずっと大きい。","subitem_description_language":"ja","subitem_description_type":"Other"},{"subitem_description":"In order to understand the reason why fine grains are deposited slowly, which is a familiar geoscientific phenomenon, we must consider the drag caused by viscosity besides the gravity and buoyancy as a force acting on falling grains in fluid such as water or air. When the grains may be as the first approximation regarded as spheres, the drag acting on the grains is in proportion to the diameter of grains, the viscosity of fluid and the falling velocity, as shown by Stokes’ law.The drag increases with increasing the falling velocity, and then each grain is deposited with a constant velocity called the terminal velocity, which is achieved when the three forces of the gravity, buoyancy and drag balance with each other. The terminal velocity of grains in fluid is proportional to the square of grain size and the difference between the densities of fluid and grains and is inversely proportional to viscosity. Therefore, when the density of grains is constant, the finer the grain size is, the smaller the terminal velocity is. This is the reason why the fine grains are deposited slowly. This phenomenon universally occurs irrespective to kinds of fluid. However,the effect of drag hardly emerges in air because the viscosity of air is about one hundredth of that of water. Unless there is an extreme difference between the body sizes or the falling length is so long, the terminal velocities are almost same. On the other hand, when balloons fall in air,the larger the size of balloon is, the more slowly the balloon falls, because the density of a bigger balloon is close to that of air and then the terminal velocity becomes smaller. In case of balloons,the effect of the difference between the densities of the balloon and air on the terminal velocity is much larger than the effect of the size.","subitem_description_language":"en","subitem_description_type":"Other"}]},"item_2_full_name_24":{"attribute_name":"著者名(別表記)","attribute_value_mlt":[{"nameIdentifiers":[{"nameIdentifier":"357","nameIdentifierScheme":"WEKO"}],"names":[{"name":"Fukuchi, Tatsuro","nameLang":"en"}]}]},"item_2_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.34429/00005079","subitem_identifier_reg_type":"JaLC"}]},"item_2_publisher_8":{"attribute_name":"出版者","attribute_value_mlt":[{"subitem_publisher":"山梨大学教育学部","subitem_publisher_language":"ja"}]},"item_2_source_id_11":{"attribute_name":"NCID","attribute_value_mlt":[{"subitem_source_identifier":"AA12782269","subitem_source_identifier_type":"NCID"}]},"item_2_source_id_9":{"attribute_name":"ISSN","attribute_value_mlt":[{"subitem_source_identifier":"2433-0418","subitem_source_identifier_type":"ISSN"}]},"item_2_text_4":{"attribute_name":"タイトルヨミ","attribute_value_mlt":[{"subitem_text_language":"ja-Kana","subitem_text_value":"ソウセツ ミジカ ナ チガク ゲンショウ ノ ブツリ : ナゼ コマカイ リュウシ ワ ユックリ タイセキ スル ノカ"}]},"item_2_version_type_20":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_version_resource":"http://purl.org/coar/version/c_970fb48d4fbd8a85","subitem_version_type":"VoR"}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2022-03-01"}],"displaytype":"detail","filename":"24330418_32_159-173.pdf","filesize":[{"value":"5.4 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"24330418_32_159-173","objectType":"fulltext","url":"https://yamanashi.repo.nii.ac.jp/record/5112/files/24330418_32_159-173.pdf"},"version_id":"12f10fcb-1abe-47c1-a0eb-64130aeae326"}]},"item_keyword":{"attribute_name":"キーワード","attribute_value_mlt":[{"subitem_subject":"地層","subitem_subject_language":"ja","subitem_subject_scheme":"Other"},{"subitem_subject":"級化層理","subitem_subject_language":"ja","subitem_subject_scheme":"Other"},{"subitem_subject":"粘性","subitem_subject_language":"ja","subitem_subject_scheme":"Other"},{"subitem_subject":"粘性抵抗","subitem_subject_language":"ja","subitem_subject_scheme":"Other"},{"subitem_subject":"圧力抵抗","subitem_subject_language":"ja","subitem_subject_scheme":"Other"},{"subitem_subject":"抗力","subitem_subject_language":"ja","subitem_subject_scheme":"Other"},{"subitem_subject":"レイノルズ数","subitem_subject_language":"ja","subitem_subject_scheme":"Other"},{"subitem_subject":"ストークスの法則","subitem_subject_language":"ja","subitem_subject_scheme":"Other"},{"subitem_subject":"stratum","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"graded bedding","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"viscosity","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"viscous drag","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"pressure drag","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"drag","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"Reynolds number","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"Stokes’ law","subitem_subject_language":"en","subitem_subject_scheme":"Other"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"jpn"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"departmental bulletin paper","resourceuri":"http://purl.org/coar/resource_type/c_6501"}]},"item_title":"《総説》身近な地学現象の物理 : なぜ細かい粒子はゆっくり堆積するのか？","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"《総説》身近な地学現象の物理 : なぜ細かい粒子はゆっくり堆積するのか？","subitem_title_language":"ja"}]},"item_type_id":"2","owner":"5","path":["514"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2022-03-01"},"publish_date":"2022-03-01","publish_status":"0","recid":"5112","relation_version_is_last":true,"title":["《総説》身近な地学現象の物理 : なぜ細かい粒子はゆっくり堆積するのか？"],"weko_creator_id":"5","weko_shared_id":-1},"updated":"2023-10-11T05:17:54.145532+00:00"}