Superelasticity, a unique property of shape memory alloys (SMAs), allows the material to recover after withstanding large deformations. This recovery takes place without any residual strains, while dissipating a considerable amount of energy. This property makes SMAs particularly suitable for applications in vibration control devices. Numerical models, calibrated with experimental laboratory tests from the literature, are used to investigate the dynamic response of three vibration control devices, built up of austenitic superelastic wires. The energy dissipation and re-centering capabilities, important features of these devices, are clearly illustrated by the numerical tests. Their sensitivity to ambient temperature and strain rate is also addressed. Finally, one of these devices is tested as a seismic passive vibration control system in a simplified numerical model of a railway viaduct, subjected to different ground accelerations.

In this paper we obtain a [finite] complete rewriting system defining a semigroup/monoid S, from a given finite
right cross-section of a subsemigroup/submonoid defined by a [finite] complete presentation. In the semigroup case the subsemigroup must have a right identity element which must also be part of the cross-section. In the monoid case the submonoid and the cross-section must include the identity of the semigroup. The result on semigroups allow us to show that if G is a group defined by a [finite] complete rewriting system then the completely simple semigroup M[G; I, J; P] is also defined by a [finite] complete rewriting system.

In this work, the design of supply chains with reverse flows is studied in a multi-objective context. A MILP model is developed for the optimization of the supply chain structures where both environmental impacts and costs are considered. An optimal Pareto front is obtained that plays an important role in evaluating the best locations of all the entities in the supply chain while accounting for the global supply chain environmental impacts. A study based on a Portuguese glass industry is presented to corroborate both the applicability and the adequacy of the model.

n/a

The progressive collapse of structures generally results in the loss of human lives. Experience shows that flat slab structures are very sensitive to progressive collapse, which may cause serious accidents if special detailing is not provided. The post-punching behaviour of a column-supported slab is decisive in the progressive collapse development. This work presents the experimental research carried out to study the post-punching behaviour of prestressed concrete flat slabs. Six reduced-scale prestressed concrete flat slab models were tested. The tests were carried out in two different phases. In the first phase the models were loaded up to failure by punching. Afterwards, the models were loaded again to study the post-punching behaviour changes caused by the presence of unbonded, prestressed tendons and the influences of their distance to the column.

n/a

n/a

A proposal for a reference curriculum for teaching Collaborative Networks at university level is introduced. This curriculum is based on the experience of the authors in teaching and disseminating corresponding concepts in the context of several international projects as well as on the findings of a survey conducted worldwide. A set of teaching units and the corresponding content are introduced. Guidelines for the application of the curriculum are given. A set of experiments and projects are also suggested as a support for the accompanying hands-on lab work. Finally, one concrete experience of application of the proposed curriculum is described.

n/a

n/a

n/a

Sauropods are often considered to have very limited mobility and reduced limb flexibility, mainly due to their giant size and consequent weight. In the Upper Jurassic Lourinhã Formation, central-west Portugal, deep vertical natural casts of sauropod manus tracks are often preserved as the infills of the original tracks. These manus tracks are vertical-walled, with marks of the striations of the skin scales, showing that the movement of the sauropod manus impacting and exiting the mud was totally vertical with no horizontal component of the stride. Some tracks are up to 66 cm deep, which is equivalent to the height of whole sauropod manus. This means that sauropods could lift their anterior feet in a complete vertical manner. Such movement is only possible if there is mobility at elbow and shoulder articulations in a higher degree than previously thought for sauropods. Our vision of sauropod limbs as inflexible columns has to be updated to a more dynamic model for limbs and body.