Some examples of multiple solutions in limiting flaw calculations using PD6493:1991 fracture mechanics analyses

The use of PC-based PD6493:1991 fracture assessment procedures has revealed that, under certain circumstances, flaws of different dimensions may be found as being limiting or critical for identical applied conditions. The main causes for multiple solutions are a steep applied stress gradient, residual stress relaxation and flaw re-characterisation. This work uses several case studies to illustrate some of the circumstances under which multiple solutions occurs.

Satellite formation in drop-on-demand printing of polymer solutions

High speed photographic images of jets formed from dilute solutions of polystyrene in diethyl phthalate ejected from a piezoelectric drop-on-demand inkjet head have been analyzed in order to study the formation and distribution of drops as the ligament collapses. Particular attention has been paid to satellite drops, and their relative separation and sizes. The effect of polymer concentration was investigated. The distribution of nearest-neighbour centre spacing between the drops formed from the ligament is better described by a 2-parameter modified gamma distribution than by a Gaussian distribution. There are (at least) two different populations of satellite size relative to the main drop size formed at normal jetting velocities, with ratios of about three between the diameters of the main drop and the successive satellite sizes. The distribution of the differences in drop size between neighbouring drops is close to Gaussian, with a small non-zero mean for low polymer concentrations, which is associated with the conical shape of the ligament prior to its collapse and the formation of satellites. Higher polymer concentrations result in slower jets for the same driving impulse, and also a tendency to form ligaments with a near-constant width. Under these conditions the mean of the distribution of differences in nearest-neighbour drop size was zero.

Globally unique product identifiers - Requirements and solutions to product lifecycle management

Managing product information for product items during their whole lifetime is challenging, especially during their usage and end-of-life phases. A major challenge is how to keep a link between the product item and its associated information, which may be stored in backend systems of different organisations. In this paper, we analyse and compare three approaches for addressing this task, i.e. the EPC Network, DIALOG and WWAI. Copyright © 2006 IFAC.