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Green port structures (i.e. green infrastructure in ports and harbors) featuring habitats for marine organisms have been promoted in Japan as part of a comprehensive policy to reduce the environmental impact of ports and carry out habitat conservation, restoration, and creation. In this study, we evaluated the ecosystem services provided by green port structures in two highly urbanized bays (Tokyo Bay and Osaka Bay) in Japan. Our results show that the provision of some ecosystem services can be limited by circumstances particular to ports and other areas with restricted access. In the case of green port structures that have strong usage restrictions, for example, cultural services can only be provided if relevant authorities are prepared to conduct public events while ensuring participant safety. On the other hand, green port structures with weak usage restrictions are often equipped with incidental facilities such as parking lots and restrooms; these facilities can enhance the provision of cultural services (e.g. recreation and environmental education). Green port structures in highly urbanized bays often have usage restrictions, but their proximity to large populations means that they can potentially provide numerous ecosystem services. However, our study shows that appropriate management goals, such as protecting species and ensuring healthy habitats, are needed to maintain the value of these services in highly urbanized and eutrophic bays.

Shigematsu, Sota Nakajo, and Yuya Okada, 2018. An Experimental Study on the Interaction between Oscillatory Flow and Idealized Porous Bed. In: Shim, J.S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 981–985. Coconut Creek (Florida), ISSN 0749-0208.The microscopic structures of over and inside flow of a porous medium placed in oscillatory flow was measured by the Particle Tracking Velocimetry with the refractive index matching method in order to investigate interaction between them. The strong shear flow was observed over the surface of the porous medium and the thickness of shear flow varied with the phase of the oscillatory flow. It was found that the thickness of non-dimensional shear flow was almost constant and that it did not depend on the Reynolds number. It was found that the thickness of non-dimensional shear flow was almost constant and it independented with the Reynolds number. Besides, it was also found that the phase difference between flows over and inside the porous bed occurred. The characteristics of the spatial variance of velocity components were shown in detail with the time phase variance. Further, the flow properties around the particle constitutes porous body were measured and investigated in detail.

Nature-based solutions (NbS), such as the implementation of environmental conservation and restoration as public works projects, require accurate and cost-effective assessments of the values related to the projects. The values should represent collective ecosystem services, individual services such as food provision and water purification, and other intangible services. To comprehensively assess such services, we proposed a novel method, which we call the comparative evaluation method. Our method is able to assess the value of each service category of an NbS project from a single questionnaire survey. Survey participants are asked to compare values of multiple services having anchoring prices. Our method determines the permissible economic value of environmental public works (PEP) in response to the quantity of service. The questionnaire results used for analysis are limited to those from respondents who made their PEP evaluation on the basis of their consideration of the appropriate expenditure of taxes. In addition, the method controls for the effect of the satisfaction that a person experiences from doing good deeds to reduce an overestimation of the values of services. Moreover, PEPs are not influenced by the respondent's annual income, age, sex, or educational background, and are based on personal values. Applying this new method, we surveyed residents of the watersheds of Tokyo Bay and Osaka Bay and evaluated nine ecosystem services. Overall, our new method is shown to be an effective method for evaluating the ecosystem services of NbS projects from the viewpoint of public works.

With the increasing demand for renewable energy in the world, research contributing to the improvement of the technology level of wave power generation is essential. The authors have been developed a wave power generation system using port facilities in inner bays with high energy-consuming cities. In this study, the relationship between the rotational characteristics of a Savonius water turbine and the water particle velocity was quantitatively evaluated under the calm conditions of the inner bay, such as wave motion, flow, and coexistence of wave and current. According to the experimental results, it is found that the relationship between the rotational circumferential speed and the water particle velocity of the water turbine installed in a wave field tends to be different from that in a flow field and is evaluated by different equations. In addition, the relationship between circumferential velocity and the water particle velocity has also been formulated when installed in a wave-current coexistence field.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/KX0XBFuao48

Details of a velocity field around a prolate spheroid in a steady flow with different angles of attack were investigated by carrying out a hydraulic experiment using the PTV technique. It was found that characteristics of the vortex in the wake of the prolate spheroid were different depending on the angle of attack. It was clearly found that the velocity field changes significantly in the wake. That is to say that there were some areas with strong and weak turbulence and that also some areas with a certain periodic and unclear periodic velocity change with significant change. It was clear that these characteristics depend on the angle of attack of the spheroid. Further, it was confirmed that the distribution of the turbulence intensity was different between the horizontal and vertical components.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/34Dw1CSLEz4

Background Pneumothorax is a rare but life-threatening complication associated with pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Case presentation Informed consent was obtained from the patient himself.A 50-year-old man presented with a 9-day history of fever, cough, and dyspnoea. He was diagnosed with coronavirus disease 2019 (COVID-19) pneumonia and was admitted to the Medical Hospital, Tokyo Medical and Dental University. Chest CT showed diffuse patchy ground-glass opacities (GGOs). His state of oxygenation deteriorated, and mechanical ventilation was initiated on day 4 after admission (12th day from onset). He improved gradually and was weaned from ventilation on day 15. Sudden onset of bilateral pneumothorax occurred on day 21 with severe respiratory failure, and chest CT revealed pneumatocele formation on both lower lobes. Conclusions Pneumothorax is a notable complication in cases of severe COVID-19 pneumonia, especially in those who require positive-pressure ventilation.

Oxygen consumption by bottom sediment in a eutrophied port and harbor is modeled based on field investigation. The model consists of factors of biological contribution and chemical-physical contribution. It is presented that these factors can be estimated by water temperature and dissolved oxygen above the sea bottom. Through modeling sediment oxygen consumption it is found that a penetration depth of oxygen is a useful parameter to represent sea bottom environment as a remediation. Further, estimation method of penetration depth of oxygen is improved to take into the change of the dissolved oxygen above sea bottom consideration.

In order to predict fluid motion induced by sediment dumped into a vertical pipe, a numerical model is developed. The numerical model is based on fundamental equation of incompressible fluid with the Boussinesq approximation and the Volume Of Fluid method is applied to trace water surface in a vertical pipe. According to comparison with laboratory experimental results, calculated results reasonably agree with experimental ones in qualitatively. The estimation results by the developed model on thickness and progressive velocity of turbidity mass on the bottom are presented with maximum ambient fluid velocity.

近年,海に隣接する大都市におけるヒートアイランド 対策の1つとして,都市人工排熱を集積し,温排水とし て河川や沿岸部へ放出する取り組みが見られる(妹尾ら, 2006).このような対策は,大気と比較して熱容量がは るかに大きい水域に都市排熱を放出することにより,大 気へ放出される熱負荷を低減させ,ヒートアイランド現 象の緩和を目指すものである.一方,ヒートアイランド 現象が顕著となる夏季には,大都市に隣接する閉鎖性海 域では密度成層による鉛直混合阻害により底層貧酸素化 が著しい(入江ら,2004).そこで,都市排熱を含んだ 水を海域に放流することにより,大気への都市排熱放出 量の削減と閉鎖性海域の鉛直混合の両者が期待され,海 域環境の改善も想定される(図-1参照). 一方,ヒートアイランドを考える上で,隣接する海域 の海面温度は海陸風の強度の重要なファクターであり, 臨海都市の気温に海面温度が影響を与えるという議論が ある.大阪湾において,玉井ら(2007)は海面温度を 1°C低下させることによって都市部の最低気温を0.3°C低 下させることができるとしている.また,二宮ら(2009) は,大阪湾の 1°Cの海面温度上昇は都市の平均気温を 0.6°C上昇させるという結果を数値計算から導いている. 上述したような,海域を利用したヒートアイランド対 策の有意性を評価するためには,日常の気象変動を正し く考慮しつつ,海域へ放出した都市排熱の海中での挙動 と熱循環として大気海洋熱交換に及ぼす影響について検 討する必要がある.既往研究(森ら,2008)においては, 海面温度が気象条件に大きく左右されるにも関わらず, 気温は一定,風速は無風を仮定しているなど,大気が海 洋に与える影響について十分に考慮できているとはいえ ない.そこで本研究では,大阪湾を対象として湾内の熱 循環を評価することができる数値モデルを構築し,気象 変動を考慮し海域の表層の流動および気液界面における 熱輸送に及ぼす影響を考慮した上で,都市排熱を海域に 放出することによる大気への排熱量の低減効果について 定量的な影響評価を行う.

The characteristics of bubble entrainment process in the surf zone are discussed. The two-phase flow measurements using two-dimensional imaging technique for bubble measurements, so called Bubble Tracking Velocimetry (BTV) were conducted in the laboratory wave tank. The horizontal and vertical distributions of void fraction and characteristic bubble size were measured and analyzed in detail. The relationship between the void fraction and wave energy dissipation are proposed for the surf zone breaking waves.

A new algorithm of a 3D particle tracking velocimetry, 3D-PLCV is developed. The significant feature is the use of images capturing path lines without any blind duration between sequential images. Hence, particle matching becomes very easy by connecting path lines in sequential images. Further, use of information of connected path line is useful to restrain generation of ghost tracers in stereo-matching. After description of details of the algorithm of the 3D-PTV developed in this study is presented, validity of the 3D-PTV is shown using artificial images. Finally, measurement result of fluid flow in pore of porous media by the developed PTV is presented.

The effect of oscillatory flow properties, the Reynolds number and the KC number, on turbulence generated by a porous media was investigated by hydraulic experiment. Violent turbulence was generated when interstitial velocity exceeded a critical level. Turbulent energy generated in pores increased as the Reynolds number increased. In a porous media, difference between minimum and maximum values of turbulent energy was increased as the KC number increased. And outside porous media, turbulent energy spread widely as the KC number increased. Under unsteady oscillatory flow, maximum turbulent energy was larger than that of unidirectional steady flow.

Field investigation of a tidal river was carried out in order to understand environmental structure at the Doi river flowing in Sakai, Osaka. On the basis of the distribution of velocity, salinity, dissolved oxygen, and so on, responsible mechanism of degraded environment was presumed. As one of possible restoration method, horizontal ejection of fresh water with rich dissoved oxygen just above the bottom was proposed. Impact assessment of the ejection was also presented with experimental results by using the particle image velocimetry.

An image velocimetry technique for measuring fluid motion of liquid-solid flow with high particle density is developed and presented. The new technique, which obtains velocities and directions by connecting path lines of tracers in sequence images captured by high speed cameras, is classified into a kind of particle tracking velocimetry. Detail of the algorithm of the developed image velocimetry, called path line connecting velocimetry (PLCV), is presented. Some results of measuring liquid-solid flows induced by dispersion phase with high concentration are presented.

The effect of Reynolds number on the properties of turbulence generated by a porous media was investigated by a hydraulic experiment. Velocity field inside and around the porous media was measured with a high resolution temporally and spatially using the Super-resolution KC method and a refractive index matching method. It is presented that some properties of turbulence can be normalized by a characteristic velocity and a diameter of the sphere which constitute the porous media.

The stratification of upper layer of coastal water can be regarded as an unused energy source for heat pump systems near coastal area in the summer. This study examines feasibility of heat pump system for coastal area using a cold water mass beneath the thermal stratified upper water. The field observations for thermalcharacteristics in the harbor were conduced through the summer season. The characteristics of stratified water are investigated by the field observations and numerical simulations. The breakdown of stratification is also examined by the numerical simulations for the heat pump system using the coastal water.

A new technique of three-dimensional hybrid stereoscopic particle image velocimetry (3D hybrid SPIV) for measuring a volumetric spatial distribution of three-dimensional velocity is presented in this paper. The accuracy and uncertainty of this technique are examined by numerical tests. The 3D hybrid SPIV has been found to be able to measure major features of velocity field involving a vortex with turbulence in a shear flow. This technique is used for measuring an instantaneous three-dimensional flow structure under breaking waves. The formation of the three-dimensional vortex structures involving roller and longitudinal vortices in breaking waves is investigated in this study.