Aims In eroded lands of the French Southern Alps,burial of early established seedlings under marly sediment weakens the effect of vegetation on soil stabilization and sediment trapping.Therefore,this protective role i...Aims In eroded lands of the French Southern Alps,burial of early established seedlings under marly sediment weakens the effect of vegetation on soil stabilization and sediment trapping.Therefore,this protective role is largely dependent on species’resistance to burial,and the understanding of species’tolerance to this environmental disturbance is highly valuable for basic knowledge on plant succession and for ecological restoration purposes.Methods The response of five woody species with contrasting ecological requirements and natural habitats—three tree species,Pinus nigra,Robinia pseudoacacia and Acer campestre,and two shrubs,Ononis fruticosa and Hippophae rhamnoides—to experimental burial under marly sediment was studied.Seedlings were exposed to three burial levels:no burial(control),partial burial(50%of seedling height)and complete burial(100%of seedling height).Burial tolerance was evaluated based on seedling survival,height and biomass.Biomass allocation to shoots and roots and soluble sugar and starch contents in roots and stems were measured to identify plant traits that determine species response to burial.Important Findings All species survived partial burial but only A.campestre seedlings emerged from complete burial.Tree species were more tolerant to burial and buried plants showed no significant differences with control.The two shrubs were found less tolerant and buried plants showed slower growth than controls.The results showed that species response was not related to initial soluble and starch content in roots and stems,but instead to biomass allocation pattern flexibility.展开更多
The paper studies specific pumping characteristics of the annular linear pumps with travelling field(ALIP)for liquid sodium.This research represents a preliminary step in the study and development of very large electr...The paper studies specific pumping characteristics of the annular linear pumps with travelling field(ALIP)for liquid sodium.This research represents a preliminary step in the study and development of very large electromagnetic pumps able to provide high flow rates.Since in such cases the magnetic Reynolds number are quite large,it is necessary to take into account the full magnetohydrodynamic interaction between the electromagnetic field and the liquid metal flow inside the pumping channel.The case where the velocity field is uniform in the channel cross section is firstly considered. Then,the coupling between the electromagnetic aspects with the hydrodynamic ones in a 2D axisyrnmetric fmite element model is studied,in order to compare the magnetic convection and the magnetic diffusion.展开更多
基金This work resulted from the project‘Genie biologique sur la Durance’,funded by EDF(Electricitede France)Agence de l’eau Rhone Mediterranee et Corse,Region Provence Alpes Cote d’Azurthe European Union with FEDER funds.
文摘Aims In eroded lands of the French Southern Alps,burial of early established seedlings under marly sediment weakens the effect of vegetation on soil stabilization and sediment trapping.Therefore,this protective role is largely dependent on species’resistance to burial,and the understanding of species’tolerance to this environmental disturbance is highly valuable for basic knowledge on plant succession and for ecological restoration purposes.Methods The response of five woody species with contrasting ecological requirements and natural habitats—three tree species,Pinus nigra,Robinia pseudoacacia and Acer campestre,and two shrubs,Ononis fruticosa and Hippophae rhamnoides—to experimental burial under marly sediment was studied.Seedlings were exposed to three burial levels:no burial(control),partial burial(50%of seedling height)and complete burial(100%of seedling height).Burial tolerance was evaluated based on seedling survival,height and biomass.Biomass allocation to shoots and roots and soluble sugar and starch contents in roots and stems were measured to identify plant traits that determine species response to burial.Important Findings All species survived partial burial but only A.campestre seedlings emerged from complete burial.Tree species were more tolerant to burial and buried plants showed no significant differences with control.The two shrubs were found less tolerant and buried plants showed slower growth than controls.The results showed that species response was not related to initial soluble and starch content in roots and stems,but instead to biomass allocation pattern flexibility.
文摘The paper studies specific pumping characteristics of the annular linear pumps with travelling field(ALIP)for liquid sodium.This research represents a preliminary step in the study and development of very large electromagnetic pumps able to provide high flow rates.Since in such cases the magnetic Reynolds number are quite large,it is necessary to take into account the full magnetohydrodynamic interaction between the electromagnetic field and the liquid metal flow inside the pumping channel.The case where the velocity field is uniform in the channel cross section is firstly considered. Then,the coupling between the electromagnetic aspects with the hydrodynamic ones in a 2D axisyrnmetric fmite element model is studied,in order to compare the magnetic convection and the magnetic diffusion.
