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Numerical modeling of bedload and suspended load contributions to morphological evolution of the Seine Estuary(France)

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International Journal of Sediment Research 2021年第6期36卷 723-735页

作者： Baptiste Mengual Pierre Le hir Aurélie Rivier Matthieu Caillaud Florent Grasso IFREMER DYNECO/DHYSED Laboratory Centre de Bretagne UMR 7266 LIENSs CNRS-La Rochelle University IRSN (Institut de Radioprotection et de S?reté Nucléaire) PRP-ENV/SERIS/LRC Laboratory

This numerical modeling study(i) assesses the influence of the sediment erosion process on the sediment dynamics and subsequent morphological changes of a mixed-sediment environment, the macrotidal Seine estuary, when non-cohesive particles are dominant within bed mixtures(non-cohesive regime), and(ii) investigates respective contributions of bedload and suspended load in these dynamics.A three dimensional(3 D) process-based morphodynamic model was set up and run under realistic forcings(including tide, waves, wind, and river discharge) during a 1-year period. Applying erosion homogeneously to bed sediment in the non-cohesive regime, i.e., average erosion parameters in the erosion law(especially the erodibility parameter, E0), leads to higher resuspension of fine sediment due to the presence of coarser fractions within mixtures, compared to the case of an independent treatment of erosion for each sediment class. This results in more pronounced horizontal sediment flux(two-fold increase for sand, +30% for mud) and erosion/deposition patterns(up to a two-fold increase in erosion over shoals, generally associated with some coarsening of bed sediment). Compared to observed bathymetric changes, more relevant erosion/deposition patterns are derived from the model when independent resuspension fluxes are considered in the non-cohesive regime. These results suggest that this kind of approach may be more relevant when local grain-size distributions become heterogeneous and multimodal for non-cohesive particles. Bedload transport appears to be a non-dominant but significant contributor to the sediment dynamics of the Seine Estuary mouth. The residual bedload flux represents, on average, between 17 and 38% of the suspended sand flux, its contribution generally increasing when bed sediment becomes coarser(can become dominant at specific locations). The average orientation of residual fluxes and erosion/deposition patterns caused by bedload generally follow those resulting from

关键词： Non-cohesive sand-mud mixtures Erosion Suspended sediment transport Bedload transport Morphodynamics Seine Estuary

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Effect of Biogas Digested Liquid on CH_4 and N_2O Flux in Paddy Ecosystem

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Journal of Integrative Agriculture 2014年第3期13卷 635-640页

作者： Ankit Singla kazuyuki Inubushi Bioresource Science Graduate School of Horticulture Chiba University

Biogas production generates digested slurry as a byproduct. It can be used as a fertilizer especially after its conversion into digested liquid. A pot based study was conducted in order to evaluate the effect of the application of digested liquid on CH4 and N2O flux, and plant biomass in paddy. Analysis revealed that digested liquid treated soils released more CH4 compared to ammonium sulphate and the control. Ammonium sulphate treated soil emitted the highest N20 whereas digested liquid application decreased its emission significantly. Further, the cumulative emission over 101 d of the experiment was found to be higher for CHa （16.9 to 29.9 g m^-2） compared to N20 （-49.3 to 18.9 mg m^-2） for all treatments. Digested liquid application had positive impact on plant variables such as panicle number and weight of panicles. This study suggests that digested liquid application significantly decrease N20 emission and increase CH4 emission possibly due to affecting the availability of organic C in the soil to microbial activity for methanogenesis. Another possibility for enhancing CH4 emission by following biogas digested liquid could be attributed to the increase in plant biomass.

关键词： biogas digested liquid paddy ammonium sulphate CH4 N20 plant biomass

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Effect of process parameters on microstructural and mechanical properties of *** 304L explosive cladding

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Journal of Central South University 2017年第6期24卷 1245-1251页

作者： Saravanan Somasundaram Raghukandan Krishnamurthy Hokamoto kazuyuki Department of Mechanical Engineering Annamalai UniversityAnnamalai NagarTamilnadu 608002India Department of Manufacturing Engineering Annamalai UniversityAnnamalai NagarTamilnadu 608002India Institute of Pulsed Power Science Kumamoto UniversityKurokamiKumamotoJapan

The present work pertains to the study of microstructure and mechanical properties of explosively cladded commercially pure titanium(cpTi) with austenitic stainless steel(SS 304L) subjected to varied process parameters, viz., loading ratios(mass of explosive or mass of flyer plate) and preset angles. The microstructural study reveals the transformation from straight to wavy interface while increasing loading ratios. Vickers hardness increases with loading ratios, and the maximum hardness is witnessed in the closer proximity of collision interface. Ram tensile and shear strength of explosive claddings are higher than that of parent plates. While the base plate fails in impact test, the flyer plate is deformed, indicating good impact strength. Increased mass of claddings, due to oxide formation, is witnessed in corrosion tests, which confirms the superiority of explosive claddings in corrosive environment. Triaxial weldability window, an analytical estimation for Ti-SS 304L explosive claddings, is developed and correlated.

关键词： explosive cladding titanium stainless steel microstructure strength corrosion

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Soil Acidification Stimulates the Emission of Ethylene from Temperate Forest Soils

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Advances in Atmospheric Sciences 2009年第6期26卷 1253-1261页

作者：徐星凯 kazuyuki INUBUSHI State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of Sciences Graduate School of Horticulture Chiba UniversityMatsudo

Soil acidification via acid precipitation is recognized to have detrimental impacts on forest ecosystems, which is in part associated with the function of ethylene released from the soil. However, the impacts of acidification on the cycling of ethylene in forest soils have not been fully taken into consideration in global change studies. Forest topsoils （0-5 cm） under four temperate forest stands were sampled to study the effects of a pH change on the emissions of ethylene and carbon dioxide from the soils and concentrations of dissolved organic carbon （DOC） released into the soils. Increasing acidification or alkalinization of forest soils could increase concentrations of DOC released into the soils under anoxic and oxic conditions. The ethylene emission from these forest topsoils could significantly increase with a decreasing pH, when the soils were acidified experimentally to a pH〈4.0, and it increased with an increasing concentration of DOC released into the soils, which was different from the carbon dioxide emission from the soils. Hence, the short-term stimulating responses of ethylene emission to a decreasing pH in such forest soils resulted from the increase in the DOC concentration due to acidification rather than carbon mineralization. The results would promote one to study the effects of soil acidification on the cycling of ethylene under different forest stands, particularly under degraded forest stands with heavy acid depositions.

关键词： soil acidification carbon dioxide dissolved organic carbon ethylene emission volcanic soil

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Numerical Study of the Effects of the Secondary Diaphragm and Contact Surface in Expansion Tubes

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Journal of Thermal Science 2004年第1期13卷 30-33页

作者： kazuyuki Kage Katsuya Ishimatsu Toyoyasu Okubayashi Department of Production Systems Engineering Oita University700 DannoharuOita870-1192JapanDepartment of Production Systems EngineeringOita University700 DannoharuOita870-1192JapanDepartment of Production Systems EngineeringOita University700 DannoharuOita870-1192Japan

The interaction of the shock reflected at a secondary diaphragm with the primary contact in six cases, i.e. the strengths and shapes of the contact surface are different, were explored by numerical study. The influences of the strength and shape of the contact on the developing wave pattern and the quality of the test gas are illustrated by many kinds of figures (e.g. the time-distance diagrams of the acoustic impedance contours on the axis, the acoustic impedance contours, and the time histories of pilot and static pressures).

关键词： expansion tubes secondary diaphragm shock propagation contact surface

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Numerical Study of Shock Waves Propagating through Right Angled Multiple Elbows

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Journal of Thermal Science 2005年第3期14卷 254-257页

作者： kazuyuki KAGE Mihoko Shir.yama Katsuya ISHIMATSU Department of Mechanical and Energy Systems Engineering Oita University 700 Dannoharu Oita 870-1192 Japan ProfessorDepartment of Mechanical and Energy Systems Engineering Oita University 700 Dannoharu Oita 870-1192 JapanDepartment of Mechanical and Energy Systems Engineering Oita University 700 Dannoharu Oita 870-1192 Japan

The details of the shock propagated through the right angled multiple elbows (mainly double elbow and fourfold elbow) are investigated by the numerical study. Computations were carried out by solving the two-dimensional compressible Navier-Stokes equations by using the total variation diminishing (TVD) scheme. Computations were performed for six types of elbow (two types of double elbow and four types of fourfold elbow) and two incident shock Mach numbers (Ms=1.5, 2.3). The effects of the direction and number of the bends in the stabilizing, merging and attenuating processes of the shock are numerically explored by various diagrams such as pressure contours, pressure distributions on the walls and time histories of the pressure contours, and the strength of the shock front at the location of about 20 times the length for each type of elbows was displayed.

关键词： shock wave multiple elbow shock diffraction non-uniform shock merger of shock

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Challenges of reducing excess nitrogen in Japanese agroecosystems

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Science China(Life Sciences) 2005年第Z2期48卷 928-936页

作者： kazuyuki YAGI Katsuyuki MINAMI National Institute for Agro-Environmental Sciences (NIAES) Tsukuba 305-8604 Japan

Fertilizer N use in Japan has decreased by about 30% from 1960 to 2000, while keeping a little increase in cereal yields. This has resulted in a significant increase in apparent nitrogen use efficiency, in particular for rice. On the other hand, national N load on the environment associated with the production and consumption of domestic and imported agricultural products has almost tripled during this period, mainly due to the dramatic increase of imports of food and feedstuffs. The environmental problems, including water and air pollution, caused by the excessive loads of N are serious public concerns and there is an urgent need to minimize N losses from agricultural production. In order to meet the necessity for reducing the environmental impacts by excess N, political and technological measures have been taken at regional and country levels. In recent years, the Japanese government has embarked on a series of policies to encourage transition to an environmentally conscious agriculture. Promoting proper material circulation with reducing fertilizer impact and utilizing biomass and livestock wastes is emphasized in these policies. The effectiveness of environmental assessment and planning for reducing regional and national N load has been discussed. Implementation of environmentally friendly technologies and management, both conventional and innovational, have been developed and adopted in Japanese agriculture. The effectiveness of conventional technologies in reducing environmental reactive N has been re-evaluated. Innovative technologies, such as use of controlled availability fertilizers and livestock wastes compost pellets, are being investigated and extended. A comprehensive approach that applies political and technological measures with closer cooperation is necessary to control reactive N in the environment.

关键词： nitrogen use efllciency nitrogen load environmental impacts nitrogen fertilizer Japan.

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Energy landscape decomposition for cell differentiation with proliferation effect

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National Science Review 2022年第8期9卷 144-152页

作者： Jifan Shi kazuyuki Aihara Tiejun Li Luonan Chen Research Institute of Intelligent Complex Systems Fudan University International Research Center for Neurointelligence The University of Tokyo Institutes for Advanced Study The University of Tokyo Key Laboratory of Mathematics and Its Applications (LMAM) and School of Mathematical Sciences Peking University Key Laboratory of Systems Biology Shanghai Institute of Biochemistry and Cell Biology Center for Excellence in Molecular Cell Science Chinese Academy of Sciences Key Laboratory of Systems Health Science of Zhejiang Province Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences Chinese Academy of Sciences School of Life Science and Technology Shanghai Tech University Guangdong Institute of Intelligence Science and Technology

Complex interactions between genes determine the development and differentiation of cells. We establish a landscape theory for cell differentiation with proliferation effect, in which the developmental process is modeled as a stochastic dynamical system with a birth-death term. We find that two different energy landscapes, denoted U and V, collectively contribute to the establishment of non-equilibrium steady differentiation. The potential U is known as the energy landscape leading to the steady distribution, whose metastable states stand for cell types, while V indicates the differentiation direction from pluripotent to differentiated cells. This interpretation of cell differentiation is different from the previous landscape theory without the proliferation effect. We propose feasible numerical methods and a mean-field approximation for constructing landscapes U and V. Successful applications to typical biological models demonstrate the energy landscape decomposition’s validity and reveal biological insights into the considered processes.

关键词： energy landscape cell differentiation stochastic systems

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Measurement of ethylene and methane production in a temperate forest soil using inhibition of acetylene and carbon monoxide

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Chinese Science Bulletin 2008年第7期53卷 1087-1093页

作者： XU XingKai INUBUSHI kazuyuki State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate School of Horticulture Chiba University Matsudo Chiba 271-8510 Japan

We studied in the laboratory the effects of acetylene (C2H2) concentrations on the accumulation and consumption of ethylene and methane in a temperate pine forest soil, and in situ ethylene and methane production and flush effects of nitrogen sources on both productions in the pine forest stand (Pinus sylvestris L.). The addition of C2H2 at concentrations more than 50 Pa C2H2 in the headspace caused a more than 95% reduction in rates of ethylene and methane consumption in forest soil compared to those with no C2H2. Furthermore, addition of acetylene within a range of 50 to 10, 000 Pa C2H2 induced a similar rate of methane accumulation in forest soil. Hence, it can be concluded that presence of more than 50 Pa C2H2 in the headspace is an effective method to measure methane production in forest soil. The addition of C2H2 at concentrations more than 50 Pa C2H2 induced an increasing concentration of ethylene in the headspace (P≤0.05), indicating the reduction of acetylene to ethylene in forest soil. Using inhibition of 0.5 kPa C2H2 in combination with 5 kPa carbon monoxide that inhibits the reduction of acetylene in a short term, it was observed that there was a larger in situ methane production rate (218 ± 26 μg C m-2 h-1 (μg C per square meter per hour, the same below)) than in situ ethylene produc-tion rate (92 ± 6 μg C m-2 h-1) in the pine forest soil. The addition of nitrogen sources such as urea, urea plus a nitrification inhibitor dicyandiamide, and potassium nitrate, could induce a 5-fold greater in-crease in rates of in situ ethylene and methane production compared to those in the control, particu-larly in the latter (P≤0.05). The results can promote in situ measurement of ethylene and methane production in forest soils at different sites.

关键词：乙烯甲烷温度森林土壤一氧化碳

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Temperature effects on ethylene and methane production from temperate forest soils

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Chinese Science Bulletin 2009年第8期54卷 1426-1433页

作者： XU XingKai INUBUSHI kazuyuki State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chi- nese Academy of Sciences Beijing 100029 China Graduate School of Horticulture C~hiba University Matsudo Chiba 271-8510 Japan

Change in temperature affects the activity of soil ***,there is limited knowledge about temperature effects on ethylene(C2H4) and methane(CH4) production from forest *** samples(0―5 cm) collected from different temperate forest stands(e.g.,Pinus sylvestris L.,Cryptomeria japonica,and Quercus serrata) were used to compare C2H4 and CH4 production from soils at temperature from 5 to 35℃ under oxic and anoxic *** rates of C2H4 and CH4 production from soils under oxic conditions were measured by using inhibition of acetylene(C2H2) and carbon monoxide(CO).The consumption of C2H2 by soils at an initial concentration of c.250 Pa C2H2 was negligible at 5 and 15℃,but it was significantly increased at 25 and 35℃.The presence of 2 kPa CO in the headspace gases tended to decrease the consumption of C2H2 by soils at high *** Q10 values for the soil C2H2 consumption ranged from 2.3 to 3.8,and there were no significant differences in Q10 values between these topsoil *** rate of CH4 production from each sample under oxic conditions was larger than the soil C2H4 production at 5―35℃,particularly at low temperature,and presented a smaller Q10 *** production from soil after 1 week of anoxic incubation at 5―35℃ was larger than the soil CH4 production,and presented a larger Q10 ***,CH4 produc-tion from Quercus serrata forest soil and its response to temperature increased significantly with in-cubation ***-term anoxic conditions of in situ upland forest soils are normally not prevalent,so it can be reasonably concluded that there is a larger C2H4 production rather than CH4 production under temperate forest stands due to heavy rainfall in summer.

关键词：土壤微生物活性甲烷产量土壤温度温带森林乙烯好氧条件二氧化碳气体缺氧条件

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