An electron microscopic study of nickel sulfide inclusions in toughened glass

It has been known since the early sixties that nickel sulfide inclusions cause spontaneous fracture of toughened (thermally tempered) glass, but despite the considerable amount of work done on this problem in the last four decades, failures still occur in the field with regularity. In this study we have classified (by viewing through a 60x optical microscope) inclusions into two groups, which are classic and atypical nickel sulfides. The classics look like the nickel sulfide inclusions found at the initiation-of-fracture of windows that have broken spontaneously. We have compared the structure and composition of the atypical inclusions with the structure and composition of the classics. All of the classic and atypical nickel sulfide inclusions studied in this work were found to have a composition in the range of Ni52S48 to Ni48S52. Inclusions on the nickel rich side of stoichiometric NiS were found to be two-phase assemblies, and inclusions on the sulphur rich side of NiS were single phase. It had been proposed that the atypicals were passive, and of a different composition to the classics. However, we found that the difference between passive and dangerous nickel sulfide inclusions was not a difference in composition but rather a difference in the type of material in the internal pore space. The passive's had carbon char in their internal pore space, whereas the pore space of dangerous inclusions contained Na2O. The presence of Na2O and carbon char with the inclusions indicates that the formation of the inclusions results from a reaction of a nickel-rich phase with sodium sulphate and carbon. (C) 2001 Kluwer Academic Publishers.

Glass transition in Australian honeys

Differential scanning calorimetry (DSC) was used to study the glass transition in 10 Australian honeys by scanning at 10 degrees Cmin(-1) from -130 to 50 degreesC after annealing at -50 degreesC. The honeys had moisture contents 14.9 to 18.0%, seven were from Eucalyptus species. The glass transition temperatures (T-g) ranged from -46 degrees to -38 degreesC and were significantly (p

Public Intellectuals, Book Culture and Civil Society

Introduction: the rise and rise of the public intellectual My starting point is the remarkable rise to prominence of public intellectuals – and talk about public intellectuals – over the last decade in Australia. Since 1997, especially, this has occurred around Indigenous questions with the result that issues such as the stolen generations, genocide, the apology and reconciliation have also gained new prominence. This is undeniably a good thing. New ways of thinking about history and the nation and new kinds of public ethical discourse have been put into circulation. History as battleground is preferable to the great Australian silence. And yet – my starting point is also the ambivalent effects and meanings of these recent developments, not least the way that the debates have centred so much around the figure of the 'public intellectual', the way that certain kinds of intellectuals and intellectual discourse have come to dominate the mainstream representation of the issues.

Theoretical and experimental studies of unbraced tubular trusses allowing for torsional stiffness

This paper describes the buckling phenomenon of a tubular truss with unsupported length through a full-scale test and presents a practical computational method for the design of the trusses allowing for the contribution of torsional stiffness against buckling, of which the effect has never been considered previously by others. The current practice for the design of a planar truss has largely been based on the linear elastic approach which cannot allow for the contribution of torsional stiffness and tension members in a structural system against buckling. The over-simplified analytical technique is unable to provide a realistic and an economical design to a structure. In this paper the stability theory is applied to the second-order analysis and design of the structural form, with detailed allowance for the instability and second-order effects in compliance with design code requirements. Finally, the paper demonstrates the application of the proposed method to the stability design of a commonly adopted truss system used in support of glass panels in which lateral bracing members are highly undesirable for economical and aesthetic reasons.