50 resultados para Ingold, Tim
em University of Queensland eSpace - Australia
Resumo:
Expansion tubes are impulse facilities capable of generating highly energetic hyper-sonic flows. This work surveys a broad range of flow conditions produced in the facility X1 with carbon dioxide test gas, for simulation of spacecraft entry into the Martian atmosphere. Conditions with nominal flow speeds of 7, 9, 11 and 13 km/s were tested. The freestream conditions were calibrated using static/Pitot pressure measurements and advanced optical diagnostics. An extensive set of holographic interferometry experiments was performed on flows over wedges for quantitative study of freestream and post-shock densities, and post-shock ionisation. A one-dimensional code with frozen and equilibrium chemistry capabilities was used to estimate the freestream conditions. An equilibrium chemistry model produced a good match to measured freestream quantities at the high enthalpy conditions which are a major aim of this facility's operation. The freestream in the lower enthalpy conditions was found to be heavily influenced by chemical non-equilibrium. Non-equilibrium in the final unsteady expansion process of flow generation was accounted for by switching from equilibrium to frozen chemistry at a predetermined point. Comparison between the freestream density results of holographic interferometry, pressure measurements and computations shows good agreement.
Resumo:
Wolbachia endosymbiotic bacteria are widespread in arthropods and are also present in filarial nematodes. Almost all filarial species so far examined have been found to harbor these endosymbionts. The sequences of only three genes have been published for nematode Wolbachia (i.e., the genes coding for the proteins FtsZ and catalase and for 16S rRNA). Here we present the sequences of the genes coding for the Wolbachia surface protein (WSP) from the endosymbionts of eight species of filaria. Complete gene sequences were obtained from the endosymbionts of two different species, Dirofilaria immitis and Brugia malayi. These sequences allowed us to design general primers for amplification of the wsp gene from the Wolbachia of all filarial species examined. For these species, partial WSP sequences (about 600 base pairs) were obtained with these primers. Phylogenetic analysis groups these nematode wsp sequences into a coherent cluster. Within the nematode cluster, wsp-based Wolbachia phylogeny matches a previous phylogeny obtained with ftsZ gene sequences, with a good consistency of the phylogeny of hosts (nematodes) and symbionts (Wolbachia). In addition, different individuals of the same host species (Dirofilaria immitis and Wuchereria bancrofti) show identical wsp gene sequences.
Resumo:
Time availability is a key concept in relation to volunteering, leading to organisations and governments targeting those outside paid work as a potential source of volunteers. It may be that factors such as a growth in female participation in the labour market and an increase in work hours will lead to more people saying they are simply too busy to volunteer This paper discusses how social and economic change, such as changing work patterns, are impacting on time availability. Using the 1997 ABS Time Use data, it identifies a predictive model of spare time by looking at demographic, life stage and employment related variables. Results confirm that those outside paid work, particularly the young, males and those without partners or children, are the groups most likely to have time to spare. These groups do not currently report high rates of volunteering. The paper concludes by questioning the premise that people will volunteer simply because they have time to spare. This is just one component of a range of motivations and factors that influence the decision to volunteer.
Resumo:
Argued that a new cadre of 'intellectual journalists' (such as Paul Kelly), unlike scholars of Graham Maddox's standing, have usurped critical appraisals of the possibilities of politics. This new anti-democratic liberalism wrongly suggests that political achievements reached when Australia was less rich (such as compulsory industrial arbitration) now need to abandoned, subordinating national well-being to an international policy orthodoxy.