Thermal vacancy formation in Co-based Heusler-type alloys Co(2)MnZ (Z = Si, Ge, Sn)
JOURNAL OF ALLOYS AND COMPOUNDS
Authors: Kogachi, M.; Kikuchi, S.; Fujiwara, T.; Hori, F.
Abstract
Thermal vacancy formation was studied for the Heusler-type ferromagnetic alloys Co(2)MnZ (Z = Si, Ge, Sn) as a function of temperature (773-1273 K) by the density, electrical resistivity and positron annihilation measurements. The vacancy concentration increased with increase in quenching temperature and particularly, a high vacancy concentration exceeding 2% was observed in Co2MnGe and Co2MnSn. Estimated vacancy formation and migration energies were comparable with those for B2-type FeAl and CoGa alloys with high vacancy concentration. Further, the vacancy type and the vacancy site were examined for alloys quenched from 773 K. As a result, it was suggested that the mono-vacancies are randomly distributed over the lattice sites. (C) 2009 Elsevier B.V. All rights reserved.
Differing environmental drivers of settlement across the range of southern rock lobster (Jasus edwardsii) suggest resilience of the fishery to climate change
FISHERIES OCEANOGRAPHY
Authors: Hinojosa, Ivan A.; Gardner, Caleb; Green, Bridget S.; Jeffs, Andrew; Leon, Rafael; Linnane, Adrian
Abstract
Temporal and spatial trends in settlement of the southern rock lobster, Jasus edwardsii, were examined to identify the influence of environmental variables over different spatial scales. Settlement data were collected from 1994 to 2011 along the Southern Australian and New Zealand coasts. We identified common settlement trends at a regional scale (100500 km): the magnitude of settlement at sites from South Australia (SA) and Victoria (VIC) were similar, but different to sites in Tasmania (TAS). In New Zealand, three spatial regions were identified: northern (NNZ), middle (MNZ) and southern regions (SNZ). Higher settlement in SA, VIC and MNZ occurred in years with higher rainfall and storms in spring and El Nino conditions. In TAS and SNZ, higher settlement occurred during La Nina conditions. These results suggest that settlement over regional scales is modulated by oceanic processes, but outcomes vary between regions. At a local scale, a higher wave period and wind relaxation were relatively more important than the sea surface temperature (SST) in SA and VIC. In TAS, the current velocity also influenced the strength of settlement. However, much of the local settlement variability was not explained by the models suggesting that settlement in J. edwardsii is a complex process where larval behaviour, biological factors and oceanographic processes interact over different scales. The apparently complex processes affecting settlement showed that environmental conditions that reduced settlement strength in one region of the fishery often increased settlement strength in other regions. This could provide resilience to climate change at the stock level.