The configuration evolution and macroscopic elasticity of fluid-filled closed cell composites : micromechanics and multiscale homogenization modelling

For fluid-filled closed cell composites widely distributed in nature, the configuration evolution and effective elastic properties are investigated using a micromechanical model and a multiscale homogenization theory, in which the effect of initial fluid pressure is considered. Based on the configuration evolution of the composite, we present a novel micromechanics model to examine the interactions between the initial fluid pressure and the macroscopic elasticity of the material. In this model, the initial fluid pressure of the closed cells and the corresponding configuration can be produced by applying an eigenstrain at the introduced fictitious stress-free configuration, and the pressure-induced initial microscopic strain is derived. Through a configuration analysis, we find the initial fluid pressure has a prominent effect on the effective elastic properties of freestanding materials containing pressurized fluid pores, and a new explicit expression of effective moduli is then given in terms of the initial fluid pressure. Meanwhile, the classical multiscale homogenization theory for calculating the effective moduli of a periodical heterogeneous material is generalized to include the pressurized fluid "inclusion" effect. Considering the coupling between matrix deformation and fluid pressure in closed cells, the multiscale homogenization method is utilized to numerically determine the macroscopic elastic properties of such composites at the unit cell level with specific boundary conditions. The present micromechanical model and multiscale homogenization method are illustrated by several numerical examples for validation purposes, and good agreements are achieved. The results show that the initial pressure of the fluid phase can strengthen overall effective bulk modulus but has no contribution to the shear modulus of fluid-filled closed cell composites.

No difference in 1RM strength and muscle activation during the barbell chest press on a stable and unstable surface

Exercise or Swiss balls are increasingly being used with conventional resistance exercises. There is little evidence supporting the efficacy of this approach compared to traditional resistance training on a stable surface. Previous studies have shown that force output may be reduced with no change in muscle electromyography (EMG) activity while others have shown increased muscle EMG activity when performing resistance exercises on an unstable surface. This study compared 1RM strength, and upper body and trunk muscle EMG activity during the barbell chest press exercise on a stable (flat bench) and unstable surface (exercise ball). After familiarization, 13 subjects underwent testing for 1RM strength for the barbell chest press on both a stable bench and an exercise ball, each separated by at least 7 days. Surface EMG was recorded for 5 upper body muscles and one trunk muscle from which average root mean square of the muscle activity was calculated for the whole 1RM lift and the concentric and eccentric phases. Elbow angle during each lift was recorded to examine any range-of-motion differences between the two surfaces. The results show that there was no difference in 1RM strength or muscle EMG activity for the stable and unstable surfaces. In addition, there was no difference in elbow range-of-motion between the two surfaces. Taken together, these results indicate that there is no reduction in 1RM strength or any differences in muscle EMG activity for the barbell chest press exercise on an unstable exercise ball when compared to a stable flat surface. Moreover, these results do not support the notion that resistance exercises performed on an exercise ball are more efficacious than traditional stable exercises.

Reading in brown paper : Beckett's budget and the sensationalist press in interwar Sydney

This article addresses the audience reception of sensationalist newspapers in interwar Australia through a case study of Sydney weekly Beckett's Budget. During a libel trial brought against Beckett's in 1928, readers came to its defence and their testimony reveals overlaps between reading and political allegiances: reading Beckett's equated with voting Labor. While histories of sensationalist media in Australia have rightly emphasised illicit sexuality and public outcry, connections between sensationalism and working-class political movements remain on the margins of academic interest. Responding to the question 'Do you read Beckett's?' readers' evidence at the trial constitutes an audience response and invites debate over the ways gender and class could inform political engagement in the 1920s. Viewing Beckett's Budget outside of 'brown paper' and beyond the sensationalist genre reveals a shift in Australian political culture as party strategists embraced a broader electorate, using Beckett's Budget to tap into the culture and concerns of interwar society.

Review of 'Promoting Justice through Clinical Legal Education' by Jeff Giddings, Justice Press, 2013

Review of 'Promoting Justice through Clinical Legal Education' by Jeff Giddings, Justice Press, 2013, 448 pages

The literary dawn: re-reading Louisa Lawson's poetry and politics

Scholarship on Louisa Lawson and the Dawn has necessarily often focussed on the important and wide-ranging achievements of her feminist work for women's legal, social and political rights. Indeed, as Audrey Oldfield notes, "Louisa Lawson was one of the most important figures in the New South Wales woman suffrage movement" (261). However, I want to focus here on the periodical publishing context of the Dawn as a means of pointing to further discussions of Lawson's significance as a poet. Megan Roughley has noted that the Dawn "was a forum for political causes, especially the movement for the emancipation and enfranchisement of women, and, as importantly to Louisa, the temperance movement" (ix), with influential articles appearing on a wide range of important issues including divorce reform. Yet, Lawson's construction of the Dawn was also highly literary from its first issue, with editorial choices and literary references reflecting her awareness of political and feminist literary culture. In addition to references such as the above quotation from Tennyson, Lawson included an epigraph from Joseph Addison's play Cato in the list of contents: "A day, an hour, in virtuous liberty, is worth a whole eternity in bondage." Citing Addison, a significant figure in the American Revolution, demonstrates Lawson's linking of radical class politics with feminism, as well as highlighting the importance of literary dialogues to Lawson's publishing work. Likewise, the concerns of Lawson's poetry are clearly situated within a continuing female tradition, and Lawson's poetry, when examined in the feminist literary context of the Dawn, reveals a radical and sophisticated poetics.