Compressive Behavior of (Cu0.47Zr0.45Al0.08)98Dy2 Bulk Metallic Glass at Different Strain Rates.

The mechanical properties of (Cu0.47Zr0.45Al0.08)98Dy2 bulk metallic glass (BMG) were characterized under various strain rates by quasi-static and dynamic compressive tests. In the quasi-static compressive tests, the yield stress of (Cu0.47Zr0.45Al0.08)98Dy2 BMG increased from 1234 MPa to 1844 MPa when the strain rate was increased from 0.001 s-1 to 0.01 s-1, and the yield stress decreased to 1430 MPa at the strain rate of 0.1 s-1. In the dynamic compressive tests, when the strain rate increased from 1550 s-1 to 2990 s-1, the yield stress of (Cu0.47Zr0.45Al0.08)98Dy2 BMG first decreased from 1508 MPa to 1404 MPa, and then increased to 1593 MPa. The fracture behaviors of (Cu0.47Zr0.45Al0.08)98Dy2 BMG were studied by using scanning electron microscopy to examine the fracture surface. Fracture occurred in the pure shear mode with strain rates below 2100 s-1, whereas shear fracture and normal fracture occurred simultaneously under strain rates of 2650 s-1 and 2990 s-1.

Impacts of microhabitat changes on wintering waterbird populations.

Caisang Lake, a human-modified wetland, experienced dramatic habitat alterations from the planting of lotus and culturing of crab. Whether the Caisang Lake still maintains populations of wintering waterbirds is of great concern. Here, we compare the changes in waterbird populations before and after habitat alterations in Caisang Lake and assess the driving factors leading to the dramatic changes in waterbird populations. Results indicate that wintering waterbird populations were significantly impacted by altered forage availability, with species- and guild-specific responses. Dramatic habitat alterations from planting lotus caused significant declines in areas of native vegetation, mudflats, and water that may have caused associated declines in herbivores, insectivores, and fish-eating waterbirds, respectively. In contrast, the increased size of the lotus area appears to have led to an increase in omnivorous waterbirds. A food shortage, potentially caused by a large area of Caisang Lake being used for culturing crab, might be another cause of the observed decline in fish-eating waterbirds. This study demonstrates a powerful approach to systematically evaluate waterbird responses to wetland management policies. These findings are important as efforts are made to protect the wintering waterbirds from the effects of human intervention, particularly at other Ramsar wetlands.