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http://hdl.handle.net/2115/21524
2024-03-28T14:03:52Z表紙・目次
http://hdl.handle.net/2115/90931
Title: 表紙・目次2023-12-14T15:00:00Z北海道函館市臼尻から採集されたモヨウフグArothron stellatus
http://hdl.handle.net/2115/90930
Title: 北海道函館市臼尻から採集されたモヨウフグArothron stellatus
Authors: 小幡, 光汰; 河合, 俊郎
Abstract: A single adult specimen of pufferfish, Arothron stellatus (Anonymous, 1798) (Tetraodontiformes : Tetraodontidae) was collected from the Pacific off Usujiri, Hakodate, southern Hokkaido, Japan in November 2022. The specimen represents the first and northernmost record in Hokkaido and Japan, respectively. This individual is highly possibly considered to have been transported by the Tsushima Warm Current and the Tsugaru Warm Current. Considering the difficulty of overwintering in cold temperature around southern Hokkaido, we suggest that the transportation happened not during its planktonic stage, but when it was an adult.2023-12-14T15:00:00Z小幡, 光汰河合, 俊郎A single adult specimen of pufferfish, Arothron stellatus (Anonymous, 1798) (Tetraodontiformes : Tetraodontidae) was collected from the Pacific off Usujiri, Hakodate, southern Hokkaido, Japan in November 2022. The specimen represents the first and northernmost record in Hokkaido and Japan, respectively. This individual is highly possibly considered to have been transported by the Tsushima Warm Current and the Tsugaru Warm Current. Considering the difficulty of overwintering in cold temperature around southern Hokkaido, we suggest that the transportation happened not during its planktonic stage, but when it was an adult.アルミニウム-ゼラチン系凝集剤によるカオリン懸濁液の凝集
http://hdl.handle.net/2115/90929
Title: アルミニウム-ゼラチン系凝集剤によるカオリン懸濁液の凝集
Authors: 月村, 梨乃; 関, 秀司; 丸山, 英男
Abstract: The flocculation ability of aluminum-gelatin (Al-GL) composite flocculant was examined with kaolin suspensions as functions of Al concentration (CAl), GL concentration (CGL) and pH. The flocculation performance was evaluated in terms of supernatant clarity or clarification efficiency (CE) on jar-test. Under the condition at CAl < 2.0 mM and pH 7±0.5, the ratio, CAl/CGL, was the major factor affecting the flocculation performance of Al-GL composite flocculant. CE increased sharply with increasing CAl/CGL at CAl/CGL < 20 mmol/g, and decreased gradually at CAl/CGL > 20 mmol/g. CE increased sharply with increasing pH from pH 4 to pH 5, and decreased sharply with pH from pH 8 to pH 9. Based on the experimental results and the calculated distribution of hydrolysis products of Al(III), the flocculation mechanism of kaolin by Al-GL composite flocculant was discussed.2023-12-14T15:00:00Z月村, 梨乃関, 秀司丸山, 英男The flocculation ability of aluminum-gelatin (Al-GL) composite flocculant was examined with kaolin suspensions as functions of Al concentration (CAl), GL concentration (CGL) and pH. The flocculation performance was evaluated in terms of supernatant clarity or clarification efficiency (CE) on jar-test. Under the condition at CAl < 2.0 mM and pH 7±0.5, the ratio, CAl/CGL, was the major factor affecting the flocculation performance of Al-GL composite flocculant. CE increased sharply with increasing CAl/CGL at CAl/CGL < 20 mmol/g, and decreased gradually at CAl/CGL > 20 mmol/g. CE increased sharply with increasing pH from pH 4 to pH 5, and decreased sharply with pH from pH 8 to pH 9. Based on the experimental results and the calculated distribution of hydrolysis products of Al(III), the flocculation mechanism of kaolin by Al-GL composite flocculant was discussed.アルミニウム-ゼラチン系凝集剤によるカオリン凝集体の沈降速度とろ過特性
http://hdl.handle.net/2115/90928
Title: アルミニウム-ゼラチン系凝集剤によるカオリン凝集体の沈降速度とろ過特性
Authors: 月村, 梨乃; 関, 秀司; 丸山, 英男
Abstract: The flocculation ability of aluminum-gelatin (Al-GL) composite flocculant was examined with kaolin suspensions as functions of Al concentration (CAl) and GL concentration (CGL) at pH 6.5-7.5. The reagents were added separately to the kaolin suspension in order of Al solution, pH adjuster, and GL solution. The flocculation performance was evaluated in terms of the clarification efficiency (CE), the settling velocity (v) of kaolin floc on flocculation experiment, and the specific cake resistance (α) on filtration experiment. The settling velocity was determined by an in-situ measurement of transmitted light intensity through the kaolin suspension using a self-made apparatus. Based on the obtained parameters, CE, v, and α, the optimum conditions were found to be CAl = 0.5 mM and CGL = 0.05 g/L for the flocculation of kaolin suspension of 10 g/L.2023-12-14T15:00:00Z月村, 梨乃関, 秀司丸山, 英男The flocculation ability of aluminum-gelatin (Al-GL) composite flocculant was examined with kaolin suspensions as functions of Al concentration (CAl) and GL concentration (CGL) at pH 6.5-7.5. The reagents were added separately to the kaolin suspension in order of Al solution, pH adjuster, and GL solution. The flocculation performance was evaluated in terms of the clarification efficiency (CE), the settling velocity (v) of kaolin floc on flocculation experiment, and the specific cake resistance (α) on filtration experiment. The settling velocity was determined by an in-situ measurement of transmitted light intensity through the kaolin suspension using a self-made apparatus. Based on the obtained parameters, CE, v, and α, the optimum conditions were found to be CAl = 0.5 mM and CGL = 0.05 g/L for the flocculation of kaolin suspension of 10 g/L.表紙・目次
http://hdl.handle.net/2115/90261
Title: 表紙・目次2023-08-03T15:00:00Z日本海盆と大和海盆の境界域に形成される底層前線の水平2次元乱流混合
http://hdl.handle.net/2115/90256
Title: 日本海盆と大和海盆の境界域に形成される底層前線の水平2次元乱流混合
Authors: 田谷, 浩志郎; 磯田, 豊
Abstract: The benthic front of the Japan Sea has a distinct temperature difference and is formed at the boundary between the cold, hyperoxic Japan Basin Bottom Water (JBBW) and the hot, hypoxic Yamato Basin Bottom Water (YBBW). The Previous study of Taya et al. (2022) found that the water mass classification of both bottom waters was determined using a dissolved oxygenpotential temperature diagram, and a remarkable mixing between the two bottom waters was formed near the tip of the JBBW, which entered the Yamato Basin from the Japan Basin side. In order to investigate the water mass mixing process by the horizontal vortex flow, a numerical model experiment of nonlinear non-hydrostatic pressure in a rotating system was conducted using a simple jointed bottom front of JBBW and YBBW as the initial condition. The baloclinic instability waves generated by small disturbances along the benthic front interact with each other nonlinearly and develop, leading to a two-dimensional horizontal turbulent flow near the front. From this turbulent state, cold-water horizontal eddy currents (originating from JBBW) cascading up to 10 km scale were found to have a vortex-pair structure with a pair of positive and negative vorticity. Furthermore, the Okubo-Weiss parameter is positive only on the positive vorticity side of the vortex pair (the rotational component is dominant over the strain component), and the uptake of external YBBW into the vortex flow is biased to this one side. This may be the reason for the asymmetric water mass distribution observed in the horizontal vortex flow of the seafloor trapping.2023-08-03T15:00:00Z田谷, 浩志郎磯田, 豊The benthic front of the Japan Sea has a distinct temperature difference and is formed at the boundary between the cold, hyperoxic Japan Basin Bottom Water (JBBW) and the hot, hypoxic Yamato Basin Bottom Water (YBBW). The Previous study of Taya et al. (2022) found that the water mass classification of both bottom waters was determined using a dissolved oxygenpotential temperature diagram, and a remarkable mixing between the two bottom waters was formed near the tip of the JBBW, which entered the Yamato Basin from the Japan Basin side. In order to investigate the water mass mixing process by the horizontal vortex flow, a numerical model experiment of nonlinear non-hydrostatic pressure in a rotating system was conducted using a simple jointed bottom front of JBBW and YBBW as the initial condition. The baloclinic instability waves generated by small disturbances along the benthic front interact with each other nonlinearly and develop, leading to a two-dimensional horizontal turbulent flow near the front. From this turbulent state, cold-water horizontal eddy currents (originating from JBBW) cascading up to 10 km scale were found to have a vortex-pair structure with a pair of positive and negative vorticity. Furthermore, the Okubo-Weiss parameter is positive only on the positive vorticity side of the vortex pair (the rotational component is dominant over the strain component), and the uptake of external YBBW into the vortex flow is biased to this one side. This may be the reason for the asymmetric water mass distribution observed in the horizontal vortex flow of the seafloor trapping.奥尻島を想定した楕円島後流域の島陰渦列
http://hdl.handle.net/2115/90249
Title: 奥尻島を想定した楕円島後流域の島陰渦列
Authors: 藤居, 流; 磯田, 豊; 小林, 直人
Abstract: In this study, ADCP observations were carried out on a grid of ship routes with the expectation that the island-shaded vortex would be captured around Okushiri Island in summer. Although such snapshot observation did not reveal the vortex’s generation period, anti-clockwise vortex flows were indeed observed on the eastern side of the island, and a northward migration of its vortex was also inferred. The observed vortex could be easily reproduced by a reduced gravity model with an idealized elliptical island set up in the northward flow. The model experiments have newly shown the occurrence of alternating positive and negative vortices with two-periodicities, i.e., 2.7 days and its double cycle 5.4 days.2023-08-03T15:00:00Z藤居, 流磯田, 豊小林, 直人In this study, ADCP observations were carried out on a grid of ship routes with the expectation that the island-shaded vortex would be captured around Okushiri Island in summer. Although such snapshot observation did not reveal the vortex’s generation period, anti-clockwise vortex flows were indeed observed on the eastern side of the island, and a northward migration of its vortex was also inferred. The observed vortex could be easily reproduced by a reduced gravity model with an idealized elliptical island set up in the northward flow. The model experiments have newly shown the occurrence of alternating positive and negative vortices with two-periodicities, i.e., 2.7 days and its double cycle 5.4 days.北海道函館市臼尻で採集されたハリセンボン科魚類2種の北限記録
http://hdl.handle.net/2115/90248
Title: 北海道函館市臼尻で採集されたハリセンボン科魚類2種の北限記録
Authors: 井黒, 浩輔; 今村, 央
Abstract: Three specimens of the birdbeak burrfish Cyclichthys orbicularis (Bloch, 1785) and a single specimen of the pelagic porcupine fish Diodon eydouxii Brissout de Barneville, 1846, collected from Usujiri, Hakodate, Hokkaido, Japan represent the first records from Hokkaido and northernmost records of both species. Together with Chilomycterus reticulatus (Linnaeus, 1758) and Diodon holocanthus (Linnaeus, 1758), diodontid species reported from Hokkaido. A single specimen, previously reported as a young individual of Ch. reticulatus, was reidentified as Cy. orbicularis.2023-08-03T15:00:00Z井黒, 浩輔今村, 央Three specimens of the birdbeak burrfish Cyclichthys orbicularis (Bloch, 1785) and a single specimen of the pelagic porcupine fish Diodon eydouxii Brissout de Barneville, 1846, collected from Usujiri, Hakodate, Hokkaido, Japan represent the first records from Hokkaido and northernmost records of both species. Together with Chilomycterus reticulatus (Linnaeus, 1758) and Diodon holocanthus (Linnaeus, 1758), diodontid species reported from Hokkaido. A single specimen, previously reported as a young individual of Ch. reticulatus, was reidentified as Cy. orbicularis.富山湾深層における近慣性内部重力波
http://hdl.handle.net/2115/90245
Title: 富山湾深層における近慣性内部重力波
Authors: 越後, 友利果; 磯田, 豊; 千手, 智晴
Abstract: The present study analyses current velocity data moored in Toyama Bay, where the incidence of near-inertial waves is restricted to southward propagation from the north, and provides evidence of their southward propagation from the flattened shape of the observed velocity ellipse. The results support the existence of near-inertial waves in a ‘non-traditional f-plane’ as pointed out by Echigo et al. (2022). Furthermore, the ray-path of its southward propagating near-inertial waves was found to be almost identical to the upward angle of the reflected waves and the slope gradient of the seabed near the bay-head. The rotating oscillatory currents associated with these near-inertial waves are expected to roll up the seabed mud and generate the turbidity flows.2023-08-03T15:00:00Z越後, 友利果磯田, 豊千手, 智晴The present study analyses current velocity data moored in Toyama Bay, where the incidence of near-inertial waves is restricted to southward propagation from the north, and provides evidence of their southward propagation from the flattened shape of the observed velocity ellipse. The results support the existence of near-inertial waves in a ‘non-traditional f-plane’ as pointed out by Echigo et al. (2022). Furthermore, the ray-path of its southward propagating near-inertial waves was found to be almost identical to the upward angle of the reflected waves and the slope gradient of the seabed near the bay-head. The rotating oscillatory currents associated with these near-inertial waves are expected to roll up the seabed mud and generate the turbidity flows.表紙・目次
http://hdl.handle.net/2115/87421
Title: 表紙・目次2022-12-01T15:00:00Z