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We present a study of the influence of interparticle cohesive forces on the packing of spheres. This is achieved by changing the external magnetic field on iron spheres in the millimeter size range. The force of cohesion between two spheres is measured by opposing magnetic and gravitational force. The void fraction of the bed resulting from many spheres being poured into a container at a given magnetic field is measured. The void fraction of the packed spheres as a function of interparticle force is thus established. We find that the void fraction is determined only by the ratio of interparticle force to particle weight, regardless of particle size. This is shown to be a universal effect, not limited to magnetic systems.

The static angle of repose for iron spheres in a narrow box, and the dynamic angle of repose for iron spheres in a narrow, half-filled rotating drum is investigated. A feature of this paper is the use of a homogenous magnetic field to induce an attractive interparticle force, allowing a wide range of angles of repose to be investigated and characterized as a function of interparticle force. The static and dynamic angles of repose were found to increase approximately linearly with increasing interparticle force.

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The 2005 ‘Work Choices’ legislation builds on earlier legislative and policy measures of the Howard Coalition Government that have restricted the activities and undermined the traditional legal rights of unions. This article highlights the key aspects of the 2005 legislation affecting trade unions. The constitutional basis of the new framework for regulating registered organisations is considered, as it presents unions with the challenge to revisit the validity of their registration under Federal law or to ‘opt out’ of registration altogether. The new union ‘right of entry’ provisions provide employers with far greater scope to resist or limit unwanted union influence at the workplace. Amendments to the freedom of association ‘provisions will restrict unions’ capacity to engage in a range of tactics to support the collective representation of workers' interests, and limit their ability to block de-unionisation or individualisation strategies by employers. We conclude that the 2005 Act constitutes the most serious threat to Australian unions yet, but that the high-profile debate generated by the reforms, and the erosion of conditions which will inevitably follow for some workers, provide opportunities for unions to re-establish their relevance and reverse declining membership levels.