Curtin University

About: Curtin University is a education organization based out in Perth, Western Australia, Australia. It is known for research contribution in the topics: Population & Zircon. The organization has 14257 authors who have published 48997 publications receiving 1336531 citations. The organization is also known as: WAIT & Western Australian Institute of Technology.

The concept of mental toughness: Tests of dimensionality, nomological network and traitness

Abstract: This article was published in Journal of Personality on 27 February 2014 (online), available at: http://dx.doi.org/10.1111/jopy.12079

CO2–Water–Rock Wettability: Variability, Influencing Factors, and Implications for CO2 Geostorage

Abstract: Carbon geosequestration (CGS) has been identified as a key technology to reduce anthropogenic greenhouse gas emissions and thus significantly mitigate climate change. In CGS, CO2 is captured from large point-source emitters (e.g., coal fired power stations), purified, and injected deep underground into geological formations for disposal. However, the CO2 has a lower density than the resident formation brine and thus migrates upward due to buoyancy forces. To prevent the CO2 from leaking back to the surface, four trapping mechanisms are used: (1) structural trapping (where a tight caprock acts as a seal barrier through which the CO2 cannot percolate), (2) residual trapping (where the CO2 plume is split into many micrometer-sized bubbles, which are immobilized by capillary forces in the pore network of the rock), (3) dissolution trapping (where CO2 dissolves in the formation brine and sinks deep into the reservoir due to a slight increase in brine density), and (4) mineral trapping (where the CO2 introduced...

A mass of less than 15 solar masses for the black hole in an ultraluminous X-ray source

Abstract: Ground-based and satellite observations show that the black hole in the ultraluminous X-ray source P13 has a mass of less than 15 times that of the Sun and displays the properties that typically distinguish ultraluminous X-ray sources from other stellar-mass black holes. Ultraluminous X-ray sources (ULXs) are non-nuclear point sources that are widely believed to contain either intermediate mass black holes or smaller, stellar mass black holes accreting from a binary companion. The study of ULXs provides information about black hole formation and/or modes of high Eddington rate accretion. Two papers in this issue of Nature describe pulsating ULXs with unusual properties. Christian Motch et al. find that source P13 in the galaxy NGC 7793 is in a ∼64 day period binary system. By modelling the strong optical and UV modulations arising from X-ray heating of the B9Ia donor star, they constrain the black hole mass to be less than 15 solar masses. Matteo Bachetti et al. observe a source in the galaxy M82 that, the pulsation data imply, harbours a neutron star rather than a black hole, raising doubts over the assumption that black holes power the most luminous X-ray binaries. Most ultraluminous X-ray sources1 have a typical set of properties not seen in Galactic stellar-mass black holes. They have luminosities of more than 3 × 1039 ergs per second, unusually soft X-ray components (with a typical temperature of less than about 0.3 kiloelectronvolts) and a characteristic downturn2,3 in their spectra above about 5 kiloelectronvolts. Such puzzling properties have been interpreted either as evidence of intermediate-mass black holes4,5 or as emission from stellar-mass black holes accreting above their Eddington limit6,7, analogous to some Galactic black holes at peak luminosity8,9. Recently, a very soft X-ray spectrum was observed in a rare and transient stellar-mass black hole10. Here we report that the X-ray source P13 in the galaxy NGC 779311 is in a binary system with a period of about 64 days and exhibits all three canonical properties of ultraluminous sources. By modelling the strong optical and ultraviolet modulations arising from X-ray heating of the B9Ia donor star, we constrain the black hole mass to be less than 15 solar masses. Our results demonstrate that in P13, soft thermal emission and spectral curvature are indeed signatures of supercritical accretion. By analogy, ultraluminous X-ray sources with similar X-ray spectra and luminosities of up to a few times 1040 ergs per second can be explained by supercritical accretion onto massive stellar-mass black holes.