Geomorphology Processes of Channel Planform Migration on Meandering Rivers

1 Introduction Morphological analysis on the planform migration structure of meandering river is an important basis for the reconstruction of evolution of paleochannel.Besides,it is a significant method for restoration of rivers through the

Spatiotemporal variability of channel and bar morphodynamics in the Gorai-Madhumati River,Bangladesh using remote sensing and GIS techniques

Bangladesh is a riparian country that is criss-crossed by the many tributaries and distributaries of the mighty Ganges,Brahmaputra,and Meghna river systems.Gorai-Madhumati,a distributary of the Ganges River is an example where morphological development of the river is associated with frequent channel shifting within the catchment area.The main objective of this research is to quantify the extent of channel migration,erosion-accretion,river width,sinuosity,and charland morpho-dynamics from 1972 to 2018 using geospatial techniques combined with satellite images and hydrological data.The study also addressed the impacts of Farakka Barrage construction in India on the shifting,flow behavior,and siltation of Gorai-Madhumati River.The study shows that bar surface areas have abnormally increased in both segments after 1975 due to the construction of Farakka Barrage.Water flow in the Gorai-Madhumati has dropped remarkably in the downstream and instigated huge sedimentation in this region.Analysis of the time series satellite images revealed that the morphology of the river channel experienced huge changes simultaneously with the changes in the seasonal flow and sedimentation all over the study period.Migration trend has frequently shifted and taken place in the NW and NE direction in the observed sections of the river.Throughout the study period,total amount of accretion was greater than the net percentage of erosion on both banks of the river.River discharge,bar accretion,and erosion history show that the Gorai-Madhumati River will no longer exist with the present flowing condition without attention and proper river management.

Ultrahigh-power electrochemical double-layer capacitors based on structurally integrated 3D carbon tube arrays

The rational design of electrodes is the key to achieving ultrahigh-power performance in electrochemical energy storage devices.Recently,we have constructed well-organized and integrated three-dimensional(3D)carbon tube(CT)grids(3D-CTGs)using a 3D porous anodic aluminum oxide template-assisted method as electrodes of electrical double-layer capacitors(EDLCs),showing excellent frequency response performance.The unique design warrants fast ion migration channels,excellent electronic conductivity,and good structural stability.This study achieved one of the highest carbon-based ultrahigh-power EDLCs with the 3D-CTG electrodes,resulting in ultrahigh power of 437 and 1708 W·cm−3 with aqueous and organic electrolytes,respectively.Capacitors constructed with these electrodes would have important application prospects in the ultrahigh-power output.The rational design and fabrication of the 3D-CTGs electrodes have demonstrated their capability to build capacitors with ultrahighpower performance and open up new possibilities for applications requiring high-power output.