The formation and survival probability of negative carbon ions sputtered from a graphite sample was determined. The energy distribution of Cy ions was measured experimentally and the energy distribution of all sputtered carbon atoms was obtained from a computer simulation with the program TRIM.SP. From the two distributions, we obtained the probability that a carbon atom would capture an electron from the graphite and subsequently survive as it moves away from the surface. Ż. The results show two different situations. At low energy below 25 eV , the sputtered particles are all negatively ionized when the affinity level crosses the graphite Fermi level and afterwards, the population decay follows a semi-classical rate equation. Ż.At higher energy above 25 eV , a velocity-dependent fraction reaches the crossing distance as neutral atoms

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We describe our experimentation with the design and implementation of specific environments, consisting of heterogeneous computational, visualization, and control components. We illustrate the approach with the design of a problem–solving environment supporting the execution of genetic algorithms. We describe a prototype supporting parallel execution, visualization, and steering. A life cycle for the development of applications based on genetic algorithms is proposed.

Presacral vertebrae of a new Diplodocidae from the Late Jurassic Amoreira-Porto Novo Formation of Lourinhã, Portugal are described and figured. Dinheirosaurus lourinhanensis gen. et sp. is diagnosed by well developed accessory articulations derived from the hyposphene, exposed in lateral view; and by the smaller dorsoventral length of the lower section of the neural arch. It is considered that the organization of the dorsal neural arch of Dinheirosaurus is more derived than in Diplodocus, except in the dorsoventral development of the lower portion of it, which is higher (more derived) in the latter. Possibly the isolated geography of Portugal in the Late Jurassic gave rise to the distinct characters of this new genus.

The numerical implementation of the displacement model of the hybrid-{T}refftz finite element formulation is presented. The geometry of the supporting element is not constrained a priori. Unbounded, non-convex and multiply connected elements can be used. The approximation basis is naturally hierarchical and very rich. It is constructed on polynomial solutions of the governing differential equation, and extended to include the particular terms known to model accurately important local effects, namely the singular stress patterns due to cracks or point loads. Numerical and semi-analytical methods are used to compute the finite element matrices and vectors, all of which present boundary integral expressions. Appropriate procedures to store, manipulate and solve symmetric highly sparse systems are used. The characteristics of the finite element solving system in terms of sparsity and conditioning are analysed, as well as its sensitivity to the effects of mesh distortion, incompressibility and rotation of the local reference systems. Benchmark tests are used also to illustrate the performance of the element in the estimation of displacements, stresses and stress intensity factors.

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Partners search and selection is an important activity in the life cycle of a Virtual Enterprise. Among other factors, the commitment of the potential partners to fulfil quality requirements is a major decision criterion during the selection phase. An approach to search suppliers in suppliers’ directories available on Internet is presented and the major negotiation steps leading to an adequate selection of partners are introduced. The quality-related information management functionalities required in a virtual enterprise support platform are also discussed.