298 resultados para Wrought Mg-Zn-RE alloys
Resumo:
Adolescents are both aware of and have the impetuous to exploit aspects of Science, Technology, Engineering and Mathematics (STEM) within their personal lives. Whether they are surfing, cycling, skateboarding or shopping, STEM concepts impact their lives. However science, mathematics, engineering and technology are still treated in the classroom as separate fragmented entities in the educational environment where most classroom talk is seemingly incomprehensible to the adolescent senses. The aim of this study was to examine the experiences of young adolescents with the aim of transforming school learning at least of science into meaningful experiences that connected with their lives using a self-study approach. Over a 12-month period, the researcher, an experienced secondary-science teacher, designed, implemented and documented a range of pedagogical practices with his Year-7 secondary science class. Data for this case study included video recordings, journals, interviews and surveys of students. By setting an environment empathetic to adolescent needs and understandings, students were able to actively explore phenomena collaboratively through developmentally appropriate experiences. Providing a more contextually relevant environment fostered meta-cognitive practices, encouraged new learning through open dialogue, multi-modal representations and assessments that contributed to building upon, re-affirming, or challenging both the students' prior learning and the teacher’s pedagogical content knowledge. A significant outcome of this study was the transformative experiences of an insider, the teacher as researcher, whose reflections provided an authentic model for reforming pedagogy in STEM classes.
Resumo:
Newberyite Mg(PO3OH)•3H2O is a mineral found in caves such as from Moorba cave, Jurien Bay, Western Australia, the Skipton Lava tubes (SW of Ballarat, Victoria, Australia) and in the Petrogale Cave (Madura , Eucla, Western Australia). Because these minerals contain oxyanions, hydroxyl units and water, the minerals lend themselves to spectroscopic analysis. Raman spectroscopy can investigate the complex paragenetic relationships existing between a number of ‘cave’ minerals. The intense sharp band at 982 cm-1 is assigned to the PO43- ν1 symmetric stretching mode. Low intensity Raman bands at 1152, 1263 and 1277 cm-1 are assigned to the PO43- ν3 antisymmetric stretching vibrations. Raman bands at 497 and 552 cm-1 are attributed to the PO43- ν4 bending modes. An intense Raman band for newberyite at 398 cm-1 with a shoulder band at 413 cm-1 is assigned to the PO43- ν2 bending modes. The values for the OH stretching vibrations provide hydrogen bond distances of 2.728Å (3267 cm-1), 2.781Å (3374cm-1), 2.868Å (3479 cm-1), and 2.918Å (3515 cm-1). Such hydrogen bond distances are typical of secondary minerals. Estimates of the hydrogen-bond distances have been made from the position of the OH stretching vibrations and show a wide range in both strong and weak bonds.
Resumo:
The recognition of Indigenous knowledge in western academic institutions challenges colonial discourses which have informed and shaped knowledge about Indigenous peoples, cultures and histories. Deeper analysis is required of the ways in which Indigenous knowledge and perspectives are perceived, and the processes through which university curricula can accommodate Indigenous knowledge in teaching and learning. To achieve this deeper analysis, and to invigorate the continuing decolonisation of Australian university curricula, this paper critically interrogates the methodology and conceptualisation of Indigenous knowledge in embedding Indigenous perspectives (EIP) projects in the university curriculum by drawing from tenets of critical race theory and the cultural interface (Nakata, 2007). Accordingly, we conduct this analysis from the standpoint that Indigenous knowledge in university curricula should not subscribe to the luxury of independence of scholarship from politics and activism. The learning objective is to create a space to legitimise politics in the intellectual / academic realm (Dei, 2008, p. 10). We conclude by arguing that critical race theory’s emancipatory, future and action-oriented goals for curricula (Dei, 2008) would enhance effective and sustainable embedding initiatives, and ultimately, preventing such initiatives from returning to the status quo (McLaughlin & Whatman, 2008).
Resumo:
Resource-intensive, high-carbon, Western lifestyles are frequently criticised as unsustainable and deeply unsatisfying. However, these lifestyles are still attractive to the majority of Westerners and to a high proportion of the developing world’s middle classes. This paper argues that the imminent threat of catastrophic climate change constitutes an immediate political, economic and ethical challenge for citizens of the developed world that cannot be tackled by appeals to asceticism or restraint. There can be no solution to climate change until sustainable conceptions of the good life are developed that those in the west want to live and which others might want to live. While the ultimate solution to climate change is the development of low carbon lifestyles, it is important that government initiatives, governance arrangements and economic incentives support rather than undermine that search. Like the global financial crisis, the climate change crisis also demonstrates what happens when weaknesses in national, corporate and professional governance are exacerbated by weaknesses in global governance. In tackling the latter, it is critical the mistakes now evidenced in the former are avoided – including a rethinking of carbon market and carbon tax alternatives. It is also critical that individuals must take responsibility for their actions as consumers, voters and investors.
Resumo:
Abstract As regional and continental carbon balances of terrestrial ecosystems become available, it becomes clear that the soils are the largest source of uncertainty. Repeated inventories of soil organic carbon (SOC) organized in soil monitoring networks (SMN) are being implemented in a number of countries. This paper reviews the concepts and design of SMNs in ten countries, and discusses the contribution of such networks to reducing the uncertainty of soil carbon balances. Some SMNs are designed to estimate country-specific land use or management effects on SOC stocks, while others collect soil carbon and ancillary data to provide a nationally consistent assessment of soil carbon condition across the major land-use/soil type combinations. The former use a single sampling campaign of paired sites, while for the latter both systematic (usually grid based) and stratified repeated sampling campaigns (5–10 years interval) are used with densities of one site per 10–1,040 km². For paired sites, multiple samples at each site are taken in order to allow statistical analysis, while for the single sites, composite samples are taken. In both cases, fixed depth increments together with samples for bulk density and stone content are recommended. Samples should be archived to allow for re-measurement purposes using updated techniques. Information on land management, and where possible, land use history should be systematically recorded for each site. A case study of the agricultural frontier in Brazil is presented in which land use effect factors are calculated in order to quantify the CO2 fluxes from national land use/management conversion matrices. Process-based SOC models can be run for the individual points of the SMN, provided detailed land management records are available. These studies are still rare, as most SMNs have been implemented recently or are in progress. Examples from the USA and Belgium show that uncertainties in SOC change range from 1.6–6.5 Mg C ha−1 for the prediction of SOC stock changes on individual sites to 11.72 Mg C ha−1 or 34% of the median SOC change for soil/land use/climate units. For national SOC monitoring, stratified sampling sites appears to be the most straightforward attribution of SOC values to units with similar soil/land use/climate conditions (i.e. a spatially implicit upscaling approach). Keywords Soil monitoring networks - Soil organic carbon - Modeling - Sampling design
Resumo:
The making of the modern world has long been fuelled by utopian images that are blind to ecological reality. Botanical gardens are but one example – who typically portray themselves as miniature, isolated 'edens on earth'. Whilst respected, heritage-laden institutions such as the Royal Botanical Gardens in Sydney, Australia promote such an idealised image they are now self-evidently also the vital ‘lungs’ of a crowded city as well as a critical habitats for threatened biodiversity (in this case notably flying foxes). In 2010 the 'Remnant Emergency Artlab' set out to alleviate this utopian hangover through a creative provocation called the 'Botanical Gardens ‘X-Tension’ - an imagined city-wide, distributed, network of 'ecological gardens' - in order to ask, what now needs to be better understood, connected and therefore ultimately conserved?
Resumo:
There are large uncertainties in the aerothermodynamic modelling of super-orbital re-entry which impact the design of spacecraft thermal protection systems (TPS). Aspects of the thermal environment of super-orbital re-entry flows can be simulated in the laboratory using arc- and plasma jet facilities and these devices are regularly used for TPS certification work [5]. Another laboratory device which is capable of simulating certain critical features of both the aero and thermal environment of super-orbital re-entry is the expansion tube, and three such facilities have been operating at the University of Queensland in recent years[10]. Despite some success, wind tunnel tests do not achieve full simulation, however, a virtually complete physical simulation of particular re-entry conditions can be obtained from dedicated flight testing, and the Apollo era FIRE II flight experiment [2] is the premier example which still forms an important benchmark for modern simulations. Dedicated super-orbital flight testing is generally considered too expensive today, and there is a reluctance to incorporate substantial instrumentation for aerothermal diagnostics into existing missions since it may compromise primary mission objectives. An alternative approach to on-board flight measurements, with demonstrated success particularly in the ‘Stardust’ sample return mission, is remote observation of spectral emissions from the capsule and shock layer [8]. JAXA’s ‘Hayabusa’ sample return capsule provides a recent super-orbital reentry example through which we illustrate contributions in three areas: (1) physical simulation of super-orbital re-entry conditions in the laboratory; (2) computational simulation of such flows; and (3) remote acquisition of optical emissions from a super-orbital re entry event.
Resumo:
Hayabusa, an unmanned Japanese spacecraft, was launched to study and collect samples from the surface of the asteroid 25143 Itokawa. In June 2010, the Hayabusa spacecraft completed it’s seven year voyage. The spacecraft and the sample return capsule (SRC) re-entered the Earth’s atmosphere over the central Australian desert at speeds on the order of 12 km/s. This provided a rare opportunity to experimentally investigate the radiative heat transfer from the shock-compressed gases in front of the sample return capsule at true-flight conditions. This paper reports on the results of observations from a tracking camera situated on the ground about 100 km from where the capsule experienced peak heating during re-entry.
Resumo:
This article considers teachers’ work as they grapple with theories in practice in the everyday worlds of their classroom. It argues that Bourdieu’s theory of practice and the concept of habitus may be useful in moving past theory/practice dichotomies. After establishing the historical context for teacher research in South Australia, the work of two school-based literacy educators with an overt social justice standpoint is explored. The complexity of teachers’ intellectual work and identity formation over time is outlined and implications for teacher education are discussed.
Resumo:
Despite the evidence that Australia’s children are learning literacy, there is also significant evidence that the poorest and most disadvantaged children are being left behind. To date our understanding of the place of transitions in this has been limited, although there has been work on the fourth grade slump (Gee, 2000, 2008), the transition from primary years to secondary years (e.g. Bahr & Pendergast, 2007; Pendergast & Bahr, 2005, 2010), and transitions when changing schools (Henderson, 2008). In this chapter, we consider the notion of transitioning, as we unpack issues related to recognising and valuing student diversity and difference. We want to highlight ways of providing high quality and high equity literacy pedagogy and literacy outcomes for middle years students. We will also discuss the importance of recognising that students transit to schools and school learning from other significant contexts, each with their own combinations of literacy practices, rituals and values.