{"created":"2023-07-25T08:04:12.177536+00:00","id":2345,"links":{},"metadata":{"_buckets":{"deposit":"184d559c-bcbd-4e8c-8ade-c08c81e40e35"},"_deposit":{"created_by":3,"id":"2345","owners":[3],"pid":{"revision_id":0,"type":"depid","value":"2345"},"status":"published"},"_oai":{"id":"oai:ir.kagoshima-u.ac.jp:00002345","sets":["228:262:5782"]},"author_link":["101409","101410","101411"],"item_7_alternative_title_18":{"attribute_name":"別言語のタイトル","attribute_value_mlt":[{"subitem_alternative_title":"Fundamental Studies on the Function of Ground Rope of Drag Net"}]},"item_7_alternative_title_19":{"attribute_name":"タイトルよみ","attribute_value_mlt":[{"subitem_alternative_title":"ソコビキアミ ノ グランドロープ ノ キノウ ニ カンスル キソテキ ケンキュウ"}]},"item_7_biblio_info_5":{"attribute_name":"収録雑誌名","attribute_value_mlt":[{"bibliographicIssueNumber":"2","bibliographicPageEnd":"156","bibliographicPageStart":"103","bibliographicVolumeNumber":"38","bibliographic_titles":[{"bibliographic_title":"鹿児島大学水産学部紀要=Memoirs of Faculty of Fisheries Kagoshima University"}]}]},"item_7_date_6":{"attribute_name":"作成日","attribute_value_mlt":[{"subitem_date_issued_datetime":"1989-12-25"}]},"item_7_description_4":{"attribute_name":"要約(Abstract)","attribute_value_mlt":[{"subitem_description":"The ground ropes function is to keep the net in contact with the sea bottom, and herd fishes to\nthe entrance of the bag net. In the case of thinking about selective fishing with a drag net, it is\nnecessary to clarify the shape and herding function of the ground rope. But there are very few\nreports about it. In this paper, the author considered forces acting on the ground rope under towing conditions,\nand decided the shape of it analytically. The author designed a fish herding model\nthe ground rope based on the theoretical probability of fiches entering the funnel of a net. Based\non these results, the author investigated the shape and gear efficiency of the ground rope. Finally\nthe author intended to obtain rational instructions for designing of ground rope.\n(1) The construction and weight distribution of three types of ground rope: Danish Seine, Bull\nTrawl and Trawl, (typical drag nets operated in Japan), were compared. Weight distribution of\nboth Danich Seine and Trawl are uniform. But the mean weight of the later is much heavier than\nthat of the former. It the case of comparison of Trawl and Bull Trawl, the former is long and increases its weight towards the middle.\nThe latter is short and very heavy and shows little difference in its weight distribution.\nThe difference in fishing methods are clearly influenced in the construction of the two types ground rope.\n(2) Three forces: hydraulic resistance of netting concentrated at the lacign line, hydraulic resistance of ground rope,\nand sliding frictional force between sea bottom are acting on the ground rope\nunder towing conditions. At equilibrium those forces made a fixed ground rope shape. The author assumed the ground rope as a connection of segments,\nand considered an equlibrium among\nthree components acting on them: horizontal, vertical and tangential components. In general it is\nimpossible to express the vertical and horizontal component acting on each segment of the ground\nrope as a simple function. Assuming that the horizontal component acting on each segment of the\nground rope is constant at any part, the length and end distances are known ahead of time, the\nshape of the ground rope was expressed graphically based on the distribution of vertical components of it which were obtained experimentaly.","subitem_description_type":"Other"},{"subitem_description":"(3) The vertical component acting on each segment of the ground rope under towing conditions\nwas expressed as the sum of hydraulic resistance, sliding frictional force and sand drag. Drag of\nclyinder type of bobbins at different lengths and that of sphere type of bobbins in various directions\nwere measured both on wet concrete and in a sand tank with water. The drag of two types bobbin on a rocky bottom (F_D) had no directional qualities, and may be expressed as the product of\nweight of bobbin (W_B) and drag coefficient (μ_90); F_D=μ_90W_B.\nThe drag coefficient of cylinder type of bobbins and sphere type of bobbins were 0.75 and 0.68\nrespectively. The drag of cylinder type of bobbins in towed on a sandy bottom is dependent upon\nthe on attack angle (90°-θ), and may be expressed the product of the weight of bobbin (W_B) and\ndrag coefficient (μθ) as follows; F_D=μθW_B.\nThe drag coefficient is a function of θ　and is expressed as follows; μθ=0.68 (0.72 sin^[1.5]θ+cos^[1.5]θ). In the case of a sphere, the drag coefficient was denoted a constant value of 0.68.\nHydraulic resistance of model ground rope composed of clyinder type of bobbins was measured\nin a circulating tank. Hydraulic drag coefficient (C_D) showed a constant value of about 0.45.\n(4) Three types of model ground rope differing in weight distribution were made. These were\nexamined both on wet concrete and sandy sea bottom under various conditions for the purpose of\nmeasuring shape and resistance. Close agreement was shown between experimental values of the\nshape and resistance of them, and those of calculated values obtained by analytically using the drag\ncoeffieients mentioned above. When the distribution of forces acting on ground rope uder towing\ncondition are known, the shape of it can be decided using the method proposed in this study. On\nthe other hand the weight distribution of ground rope for making a certain ground rope shape can\nbe decided using the method proposed in this study.","subitem_description_type":"Other"},{"subitem_description":"(5) The author paid attention to fish reaction to the ground rope and considered a fish herding\nmodel for the ground rope. Theoretical probability of fishes entering the funnel of the bag net was\ncalculated, and six theoretical types of ground rope: triangle, trapezoid, half ellipse, arc, parabola\nand catenary were compared. The fishing efficiency of trapezoid, parabola, half ellipse and catenary showed almost same values under towing condition based on the fish herding model for flat\nfish. The wing tips distance at maximum fishing efficiency was wider than usual towing conditions.\nHigher fishing efficiency would be expected under that towing condition.\nFishing efficiency of two types of ground rope, middle-weighted Bull Trawl type and heavy-weighted Trawl type,\nwere compared by towing on a sandy sea bottom using the fish herding model proposed in this study. Fishing efficiency of the former was a little higher than that of the latter. This corelates well with the results of field experiments.\n(6) The ratio of resistance of ground rope to the total resistance of drag net was about 30-35%\nunder towing condition. It is imposible to change a ground rope shape under towing condition by\nmeans of variation on the weight distribution of the ground rope. In the case of thinking on the\nground rope shape, it is necessary to consider the hydraulic resistance of netting which were concentrated to the lacing lines and acting on the ground rope. The trapezoid shape glound rope was\nshowed the fishing efficiency using the fish herding model proposed in this study. About 30-35%\nof resistance of drag net should act on the points both edge of bosom of ground rope to make a\ntrapezoid-shape ground rope. It is one method to concentrate whole drag acting on ground rope\nand hydraullic resistance of netting there as a results of many considerations on weight distribution\nof ground rope and the design of lacing lines.","subitem_description_type":"Other"}]},"item_7_full_name_2":{"attribute_name":"著者よみ","attribute_value_mlt":[{"nameIdentifiers":[{}],"names":[{"name":"フワ, シゲル"}]}]},"item_7_full_name_3":{"attribute_name":"別言語の著者","attribute_value_mlt":[{"nameIdentifiers":[{}],"names":[{"name":"FUWA, Shigeru"}]}]},"item_7_publisher_23":{"attribute_name":"公開者・出版者","attribute_value_mlt":[{"subitem_publisher":"鹿児島大学"}]},"item_7_source_id_7":{"attribute_name":"ISSN","attribute_value_mlt":[{"subitem_source_identifier":"0453087X","subitem_source_identifier_type":"ISSN"}]},"item_7_source_id_9":{"attribute_name":"NII書誌ID","attribute_value_mlt":[{"subitem_source_identifier":"AN00040498","subitem_source_identifier_type":"NCID"}]},"item_7_subject_15":{"attribute_name":"NDC","attribute_value_mlt":[{"subitem_subject":"664","subitem_subject_scheme":"NDC"}]},"item_7_text_24":{"attribute_name":"公開者よみ","attribute_value_mlt":[{"subitem_text_value":"カゴシマ ダイガク"}]},"item_7_text_25":{"attribute_name":"公開者別名","attribute_value_mlt":[{"subitem_text_value":"Kagoshima University"}]},"item_7_version_type_14":{"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_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"不破, 茂"}],"nameIdentifiers":[{}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2016-10-27"}],"displaytype":"detail","filename":"AN00040498_v38-2_p103-156.pdf","filesize":[{"value":"5.4 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"AN00040498_v38-2_p103-156.pdf","url":"https://ir.kagoshima-u.ac.jp/record/2345/files/AN00040498_v38-2_p103-156.pdf"},"version_id":"21906dfc-0735-4789-b7d5-6e25e34737e6"}]},"item_keyword":{"attribute_name":"キーワード","attribute_value_mlt":[{"subitem_subject":"Ground Rope","subitem_subject_scheme":"Other"},{"subitem_subject":"Weight Distribution","subitem_subject_scheme":"Other"},{"subitem_subject":"Drag Coefficient","subitem_subject_scheme":"Other"},{"subitem_subject":"Theoretical Analysis of Shape","subitem_subject_scheme":"Other"},{"subitem_subject":"Fish Herding Model","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":"底びき網のグランドロープの機能に関する基礎的研究","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"底びき網のグランドロープの機能に関する基礎的研究"}]},"item_type_id":"7","owner":"3","path":["40","5782"],"pubdate":{"attribute_name":"公開日","attribute_value":"2012-05-07"},"publish_date":"2012-05-07","publish_status":"0","recid":"2345","relation_version_is_last":true,"title":["底びき網のグランドロープの機能に関する基礎的研究"],"weko_creator_id":"3","weko_shared_id":3},"updated":"2024-01-30T05:48:11.769845+00:00"}