Compressive properties and energy absorption of hollow sphere aluminium

Manufactured cellular aluminums have been developed for a wide range of automotive applications where weight savings, improved safety, crashworthiness and comfort are required. The plateau deformation behavior of cellular aluminums under compressive loading makes this new class of lightweight materials suitable for energy absorption and comes close to ideal impact absorbers. In the present study, aluminum hollow hemispheres were firstly processed by pressing. Hollow sphere aluminum samples with a body-centered cubic (BCC) packing were then fabricated by bonding together single hollow spheres, which were prepared by adhering together hollow hemispheres. Hollow sphere aluminum samples with various kinds of sphere wall thicknesses of 0.1 mm, 0.3 mm and 0.5 mm but the same outside diameter of 4 mm were investigated by compressive tests. The effects of the sphere wall thickness on the mechanical properties and energy absorption characteristics were investigated.

Processing and mechanical properties of hollow sphere aluminum foams

Hollow sphere metallic foams are a new class of cellular material that possesses the attractive advantages of uniform cell size distribution and regular cell shape. These result in more predictable physical and mechanical properties than those of cellular materials with a random cell size distribution and irregular cell shapes. In the present study, single aluminum hollow spheres with three kinds of sphere wall thickness as 0.1 mm, 0.3 mm and 0.5 mm were processed by a new pressing method. Hollow sphere aluminum foam samples were prepared by bonding together single hollow spheres with simple cubic packing (SC) and body-centered cubic packing (BCC). Compressive tests were carried out to evaluate the deformation behaviors and mechanical properties of the hollow sphere aluminum foams. Effects of the sphere wall thickness and packing style on the mechanical properties were investigated.

Class act : Melbourne Workers Theatre, 1987-2007

Celebrates the company's artistic achievements and successes over the last two decades through interviews, essays and high quality images of key productions, and recounts its history, its evolving relationship with the embattled trade union movement, and its on-going engagement with working class, indigenous and migrant communities.

'Class' and political theatre : the case of Melbourne workers theatre

Traditionally, class has been an important category of identity in discussions of political theatre. However, in recent years the concept has fallen out of favour, partly because of changes in the forces and relations of capitalist production. The conventional Marxist use of the term, which defined an individual's class position in relation to the position they occupied in the capitalist production process, seemed anachronistic in an era of globalization. Moreover, the rise of identity politics, queer theory, feminism, and post-colonialism have proffered alternative categories of identity that have displaced class as the primary marker of self. Glenn D'Cruz reconsiders the role of class in the cultural life of Australia by examining the recent work of Melbourne Workers Theatre, a theatre company devoted to promoting class-consciousness, in relation to John Frow's more recent re-conceptualization of class. He looks specifically at two of the company's plays, the award-winning Who's Afraid of the Working Class? and The Waiting Room, with reference to Frow's work on class, arguing that these productions articulate a more complex and sophisticated understanding of class and its relation to politics of race and gender today.

Class action

Hannie Rayson followed the success of her play Life After George (2000) with Inheritance. It is a rural family saga set in Victoria's Mallee region where two families, headed by eighty-year-old twin sisters Dibs and Girlie, battle it out for possession of the family farm. The play, directed by Simon Phillips, was performed in March 2003 to capacity audiences at the Melbourne Theatre Company, and then at the Sydney Theatre Company in April-May 2003. Rayson's most recent play, Two Brothers, opened at the Playhouse, Victorian Arts Centre, in April 2005.

Assessment of physical activity among primary school aged children: the Children's Leisure Activities Study (CLASS)

Overweight and obesity rates among children in Australia have increased twofold in the last decade. Physical activity is thought to play an important role in the prevention and treatment of childhood obesity. Children's physical activity data in Australia are incomplete and mainly based on parental proxy reports. One of the reasons for the lack of children's physical activity prevalence data in Australia is the difficulties of measurement. The aim of this study was to develop and examine a reliable, valid and feasible method for assessing physical activity among primary school aged children. A total of 112 grade 5 and 6 children and their parents were recruited from four state primary schools in the eastern and western suburbs of Melbourne. The test-retest reliability of a parental proxy physical activity questionnaire and a children's self report physical activity questionnaire was assessed. The criterion validity of the questionnaires was assessed using accelerometry. Findings suggest that the self report and proxy report questionnaires provided reliable measures of the type, frequency and duration of children's physical activity behaviour. Overall, the criterion validity of the questionnaires was poor. Although accelerometry as an objective measure shows promise, it does not provide the important physical activity behavioural and contextual information that is critical for the development of strategies to promote physical activity among children. We recommend that a combination of self report or proxy and objective measurement (using accelerometry or even pedometry) appears to be the current 'best buy' in the assessment of children's physical activity behaviour.

Troubling identities : teacher education students' constructions of class and ethnicity

This paper reports on a research project that explored how student teachers understand ethnic and classed difference as it relates to themselves and their students. Discourses of schooling can shape students ethnic and classed identities, frequently positioning non-mainstream students as 'other' and marginalizing them. Significant numbers of our teacher education students have limited experience of diverse educational settings, having mainly attended white middle-class schools as students and as student teachers. Working with diverse student populations productively depends on teachers recognising and valuing difference. The ways in which they engage with students whose ethnic and classed identities are different from their own is important in creating learning environments that build on and engage with diversity.

In a preliminary stage of the research we asked eight third-year teacher education students to explore their own ethnic and classed identities. The complexities of identity are foregrounded in both the assumptions we made in selecting particular students for the project and in the ways they did (not) think about themselves as having ethnic or classed identities.

In this paper we draw on these findings to interrogate how categories of identity are fluid, shifting and ongoing processes of negotiation: troubling and complex. We also consider the implications for teacher education.

Ethnicity, social class, practice and pedagogy : a study of teacher identity

This paper draws on findings from three separate research projects to illustrate how teachers’ and student-teachers’ ethnic and social class identities shape theirrepresentations of professional self, their interactions with their students and the pedagogies they privilege in their classes. The paper raises a number of important implications for teacher education seeking to prepare teachers for culturally diverse contexts such as Australian classrooms. It concludes that a major challenge for teacher educators is to find ways of enabling their students to interrogate often taken-for-granted assumptions about their own ethnic and classed positionings.

Simulation of three-point bending test of titanium foam for biomedical applications

Using Titanium (Ti) foam as an implant material is a new approach for biomedical applications and it is important to understand the mechanical behaviors of this new foam material. In the present study, the bending of the Ti foam has been simulated and compared against recently published data [1]. FE Analysis has been performed by Abaqus software. Stiffness and Yield strength of foams between 50% (cortical bone) to 80% (cancellous bone) porosity range were considered. This study showed that crushable foam material model in Abaqus, which has developed primarily for Aluminum (Al) foam alloys, is also valid for Ti Foam before any crack or damage occurs in the sample.

Experienced teachers' perspectives on cultural and social class diversity : which differences matter?

This article reports on a pilot study that investigated the beliefs, values, and pedagogies of experienced high school teachers who worked with student populations of non-English speaking and economically disadvantaged immigrants or refugees in Australia. Qualitative research methods, including focus groups and in-depth individual interviews with teachers, produced data that were examined using Critical Discourse Analysis. Close reading of the teachers' comments suggests that there are a number of key discourses that teachers use to make sense of differences among culturally diverse and economically disadvantaged groups of students. Specifically, teachers distinguish between cultural groups on the basis of students' life experiences prior to arrival in Australia; students' collective and individual educational experiences; and the different social class positioning of students within the same ethnic group. In their comments, teachers at times categorised students in generalised and stereotypical ways but also were able to critique and reflect on their personal assumptions. An analysis of the teachers' reflections provides insights into how they made sense of “diversity” and how, as teachers, they try to work productively with ethnically diverse and economically disadvantaged students.

Mechanical properties of titanium foam for biomedical applications

Understanding the mechanical behaviour of pure titanium (Ti) foam is crucial for the design and development of Ti foam-based load-bearing implants. In this work, pure titanium foam is fabricated by a powder metallurgical process using the space-holder technique with a spacer size of 500 to 800 µm. Experimental data from static compression testing on the Ti foam are presented. The application of theoretical formulae to predict Young's modulus and yield strength of titanium foams is also discussed. A foam with 63% porosity, 87 ± 5 MPa yield strength, and 6.5 ± 1.3 GPa Young's modulus is found to be appropriate for a number of dental and orthopaedic applications.

The Australian class structure and Australian politics 1931 - 40

This paper presents the results of an analysis of the class structure of interwar Australia based largely on the 1933 Commonwealth census. It reviews previous analyses by academics but although contemporary journalists and political strategists. It develops an estimate of the class composition of the electorate as distinct from the general population and attempts to define the class position of voters outside of the paid workforce. It considers the question of to what extent Labor needed non-working-class votes to secure an electoral majority and how the differing social composition of the Australian states impacted on electoral outcomes and Labor strategies. It employs the method of bounds to develop some preliminary conclusions about the electoral behaviour of different social groups and concludes with some observations on the divided nature of the Australian working class and the competing strategies that parties developed in their search for an electoral majority.