The influence of bulk particulate properties on pneumatic conveying performance

Interest in the use of dense phase conveying has grown considerably in recent years. However, not all products are capable of being conveyed in dense phase and it is often difficult to predict which products have dense phase capability without carrying out pilot conveying trials. The main objective of this work was to investigate the effect of bulk particular properties on pneumatic conveying performance. To achieve this, an extensive programme of conveying trials was carried out and each product tested was subjected to a series of bench scale tests to evaluate the bulk properties of the material. A phase diagram is proposed, based on the aeration properties of a material, which groups together products of similar conveying potential. The phase diagram gives a first indication on the basis of a small sample of material whether or not a product is capable of dense phase conveying. Further, it will predict the most appropriate mode of flow. For products capable of dense phase in a moving bed type flow regime, a further correlation is proposed which predicts the likely conveying performance in the pipeline in terms of mass throughput of product for given conditions based on the air retention characteristics of a product. The correlation has been generalised to extend its applicability to a range of pipeline configurations. The combination of the phase diagram and the correlation for dense phase moving bed type flow (the most commonly used form of dense phase conveying) provides a powerful design tool which will reduce the need for full conveying trials. In addition, the effect of material bulk properties on blow tank performance has also been investigated and a correlation between aeration properties and blow tank discharge characteristics is proposed

ASEAN and the non-traditional regional security agenda

Without a doubt, the whole area of non-traditional security – whether it be threats, issues or challenges (the three are more or less used interchangeably in ASEAN statements and documents on the subject) – has come to occupy a prominent place on the regional security agenda in recent years.1 This is very much in keeping with the ‘widening’, or ‘broadening’, of the security agenda which has occurred internationally in both the academic literature and, crucially, in the policy sphere

A Note on Cosmic (p,q,r) Strings

The spectrum of $(p,q)$ bound states of F- and D-strings has a distinctive square-root tension formula that is hoped to be a hallmark of fundamental cosmic strings. We point out that the Bogomol'nyi-Prasad-Sommerfield (BPS) bound for vortices in ${\cal N}=2$ supersymmetric Abelian-Higgs models also takes the square-root form. In contrast to string theory, the most general supersymmetric field theoretic model allows for $(p,q,r)$ strings, with three classes of strings rather than two. Unfortunately, we find that there do not exist BPS solutions except in the trivial case. The issue of whether there exist non-BPS solutions which may closely resemble the square-root form is left as an open question.Comment: 4 pages; v2: references adde