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Platelet-shaped particles of similar size and shape were investigated as fillers for improving the thermal conductivity of polymer-ceramic composite materials. The conductivities of composites filled with hard, stiff ceramic particles exceeded 3.5 W⅐(m⅐K) ؊1 , or >20 times the conductivity of the polymer matrix, and were shown to be almost independent of the intrinsic filler conductivity range of 33-300 W⅐(m⅐K) ؊1 . In contrast, the thermal conductivity of composites filled with soft, platelet-shaped BN fillers reached over 13 W⅐(m⅐K) ؊1 . A mechanism is proposed whereby deformation of the soft filler particles provides improved particle-to-particle connectivity and allows greater packing density, resulting in the ability to achieve much higher conductivity than is possible for hard and stiff particles of similar initial morphology. Experimental results are discussed in light of various thermal conductivity prediction models in the literature.

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In this paper an inventory model with several demand classes, prioritised according to importance, is analysed. We consider a lot-for-lot or S , 1; S i n v entory model with lost sales. For each demand class there is a critical stock level at and below which demand from that class is not satis ed from stock on hand. In this way stock is retained to meet demand from higher priority demand classes. A set of such critical levels determines the stocking policy. F or Poisson demand and a generally distributed lead time we derive expressions for the service levels for each demand class and the average total cost per unit time. E cient solution methods for obtaining optimal policies, with and without service level constraints, are presented. Numerical experiments in which the solution methods are tested demonstrate that signi cant cost reductions can be achieved by distinguishing between demand classes.

This paper introduces the concept of using active waveguides as part of an acoustic emission monitoring system for assessing the stability of soil slopes. In soil, acoustic emissions are generated by inter-particle friction, and hence the detection of acoustic emission is an indication of straining. The components of a field monitoring system are introduced, and the factors controlling design and performance of waveguides are discussed. It is proposed that active waveguides (i.e. those that generate acoustic emission when deformed by the host soil) can be used as an efficient method of obtaining signals from depth within a deforming soil body. The results of laboratory tests conducted to validate the active waveguide model are presented. The role played by the soil surrounding the steel tube waveguide is highlighted. Results from two full-scale field trials that involved monitoring unstable slopes provide evidence for the relationship between detected acoustic emission and slope deformation rate. It is shown that active waveguides in conjunction with relevant signal processing methods can be used to provide an early indication of slope instability.

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