Variation on sandbar of tributary in Xiaolangdi Reservoir on Yellow River, China

Sandbar development would stop the water and sediment exchange between main river and tributary and even influence the normal reservoir opeartion. From the surveyed data of reservoir built many years ago, it shows that when there is a bar in tributary mouth, the tributary volume below the bar will become nullification during the period of flood control or water and sediment regulation of reservoir. There are more tributaries in Xiaolangdi reservoir than the others that it occupies 41.3% of the total initial volume of tributary volume. Obviously, the effective use of tributary volume has been important influenced by comprehensive utilization efficiency of reservoir scheduling, such as flood control, sedimentation reduction and comprehensive utilization. Results of Xiaolangdi Reservoir mobile-bed physical model experiments show that tributary is equivalent to lateral extension of river bed, the tributary intrusion deposition process have strongly relations with the factors, such as original topography, river bed deposition shape and its regime, process with input discharge and input sediment, and method of reservoir regulation. The variation trends of main river and tributary terrain forecasted by model test are basically in accordance with field surveyed data. The results could be used for research, design, and forecasting of reservoirs in sediment-laden river

Variation on sandbar of tributary in Xiaolangdi Reservoir on Yellow River, China

Sandbar development would stop the water and sediment exchange between main river and tributary and even influence the normal reservoir opeartion. From the surveyed data of reservoir built many years ago, it shows that when there is a bar in tributary mouth, the tributary volume below the bar will become nullification during the period of flood control or water and sediment regulation of reservoir. There are more tributaries in Xiaolangdi reservoir than the others that it occupies 41.3% of the total initial volume of tributary volume. Obviously, the effective use of tributary volume has been important influenced by comprehensive utilization efficiency of reservoir scheduling, such as flood control, sedimentation reduction and comprehensive utilization. Results of Xiaolangdi Reservoir mobile-bed physical model experiments show that tributary is equivalent to lateral extension of river bed, the tributary intrusion deposition process have strongly relations with the factors, such as original topography, river bed deposition shape and its regime, process with input discharge and input sediment, and method of reservoir regulation. The variation trends of main river and tributary terrain forecasted by model test are basically in accordance with field surveyed data. The results could be used for research, design, and forecasting of reservoirs in sediment-laden river

Aluminium composites prepared by laser cladding assisted by friction stir processing

A laser cladding and friction stir processing hybrid method was employed to produce an Al matrix composite layer. The microstructure, phase composition, microhardness and conductivity of the composites were investigated. A laser cladding layer with a thickness of approximately 200 μ m was prepared on a 1060 aluminium plate and it was broken up and distributed on the Al matrix after friction stir processing. The particle/Al interfaces exhibited extremely good interfacial integrity. Microstructural observations revealed that an obvious in situ reaction occurred at the particle/Al interfaces, which effectively improved the bonding between the reinforcement phase and the matrix. TEM analysis and selected area diffraction enabled the identification of the intermetallic compounds and confirmed them to be Al _5 Fe _2 and Al _3 Fe. The average microhardness values of the friction stir processed composites reached approximately 85 HV. The electrical resistivity of the friction stir processed composites is slightly higher than that of the aluminium matrix

A well-balanced strength and electrical conductivity in rolled composite prepared by in-situ TiB2p/Cu composite powder

The TiB2p/Cu composites were prepared by current-assisted vacuum hot pressing (CAVHP) combined with rolling using in-situ spherical TiB2p/Cu composite powder as raw material. The effects of rolling deformation on the microstructure and properties of the sintered TiB2p/Cu composite were investigated. The results show that CAVHP leads to a rapid densification of the composite powder compact, and the subsequent rolling deformation is able to eliminate the unclosed pores and achieve a uniform distribution of TiB2p. The dynamic recrystallization during cold rolling refines the Cu matrix grains to ultrafine grains with an average grain size of 0.47 μm. The cold rolled TiB2p/Cu composite obtains a remarkable comprehensive performance with ultimate tensile strength, yield strength and electrical conductivity of 621 MPa, 567 MPa and 86.3% IACS, respectively. In addition, the strengthening and fracture mechanism of the cold rolled TiB2p/Cu composite are analyzed. This work will explore a new technological solution for the preparation of high-performance Cu matrix composites