Automated adaptive 3D forming simulation processes

In this study, an automated adaptive mesh control scheme, based on local mesh modifications, is developed for the finite element simulations of 3D metal-forming processes. Error indicators are used to control the mesh discretization errors, and an h-adaptive procedure is conducted. The mesh size field used in the h-adaptive procedure is processed to control the discretization and geometric approximation errors of the evolving workpiece mesh. Industrial problems are investigated to demonstrate the capabilities of the developed scheme.     

A simple micro-mixer prototyped in polycarbonate

In this paper, we report on first stage results on our work on the design and prototyping of a simple polycarbonate micro-mixer. CFD simulations indicate that the elliptical shape of the mixer appears to eliminate dead volumes and to result in more uniform flow and hence more uniform mixing. The mixer has also been characterised spectrophotometrically in a simple way. A simple design may be advantageous in that it may be more reliable in the micro-scale. It is certainly easier to manufacture.The authors would like to thank Drs Jason Pickering and Hu Banghong for their valuable and constructive criticisms during the preparation of this short communication.     

Asymptotic distribution of the number of isolated nodes in wireless ad hoc networks with Bernoulli nodes

Nodes in wireless ad hoc networks may become inactive or unavailable due to, for example, internal breakdown or being in the sleeping state. The inactive nodes cannot take part in routing/relaying, and thus may affect the connectivity. A wireless ad hoc network containing inactive nodes is then said to be connected, if each inactive node is adjacent to at least one active node and all active nodes form a connected network. This paper is the first installment of our probabilistic study of the connectivity of wireless ad hoc networks containing inactive nodes. We assume that the wireless ad hoc network consists of n nodes which are distributed independently and uniformly in a unit-area disk, and are active (or available) independently with probability p for some constant 0

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