A ligação pilar-fundação tem um papel fundamental no comportamento das estruturas pré-fabricadas, em particular, na presença de acções horizontais, como a acção dos sismos e do vento, que introduzem esforços elevados na base dos pilares. Um dos sistemas de ligação pilar-fundação usados em estruturas pré-fabricadas consiste em deixar na extremidade inferior dos pilares armaduras salientes que são introduzidas em negativos executados nas fundações. Estes negativos são posteriormente injectados com grout para garantir a ligação. No presente trabalho foram estudadas diferentes soluções de negativos para ligação das armaduras do pilar à fundação, tendo sido realizados ensaios monotónicos para analisar o seu comportamento. Nesta comunicação apresentam-se e discutem-se os resultados obtidos da análise experimental efectuada.

A ligação pilar-fundação tem um papel fundamental no comportamento das estruturas pré-fabricadas,
em particular, na presença de acções horizontais, como a acção dos sismos e do vento. Um dos sistemas de ligação pilar-fundação usados em estruturas pré-fabricadas consiste em deixar na extremidade inferior dos pilares armaduras salientes que são introduzidas em negativos executados nas fundações, sejam elas sapatas ou maciços de encabeçamento de estacas. Estes negativos são posteriormente injectados com “grout” para garantir a ligação. Foram estudados diferentes soluções de negativos para ligação das armaduras do pilar na fundação. Foram realizados ensaios monotónicos e cíclicos, para analisar não só o comportamento às acções estáticas mas também para a acção sísmica. No presente trabalho apresentam-se os resultados obtidos com a análise experimental efectuada. O estudo realizado permite apresentar recomendações para projecto e quais os tipos de ligações com melhor desempenho.

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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.

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The material in analysis is the skull of an Ornitiquous Psittacosaurus of the China Cretaceous suspicious of being a fraud. The fossil described here appeared to be in very good condition and conservation. The skull is almost complete but because it is filled by sediment, this prevents an analyse of the intra-skull anatomy.
With the intuition of confirming or not the existence of fossiled bone elements in the interior of the sedimented mass that filled the Psittacossaurus skull, it was submitted to a Computorized Tomography.
The Psittacosaurus skull showed an unexpected absorption of the x-rays, because of the outstanding differences of density between the bone and the matrix due to the fact that the interior of the skull was composed by an amalgam of materials, where a less compact and relatively homogeneous material (soil and wax) was found and that material united and mounted the whole skull and the normal bone structures were non-existing.
The capacity of the Computorized Axial Tomography of differentiating materials with different densities of absorption of x-rays, permitted an easy and reliable investigation and explained beyond doubt the quality of the fossil specimen studied, concluding with no doubt that in spite of the realistic aspect, we had come before a fraud.

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Database systems are a key component behind many of today’s computer systems. As a consequence, it is crucial that database systems provide correct and continuous service despite unpredictable circumstances, such as software bugs or attacks. This paper presents the design of Byzantium, a Byzantine fault-tolerant database replication middleware that provides snapshot isolation (SI) semantics. SI is very popular because it allows increased concurrency when compared to serializability, while providing similar behavior for typical workloads. Thus, Byzantium improves on existing proposals by allowing increased concurrency and not relying on any centralized component. Our middleware can be used with off-the-shelf database systems and it is built on top of an existing BFT library.

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In this paper, a poly-phase disc motor innovative feeding and control strategy, based on a variable poles approach, and its application to a HTS disc motor, are presented. The stator windings may be electronically commutated to implement a 2, 4, 6 or 8 poles winding, thus changing the motor's torque?speed characteristics. The motor may be a conventional induction motor with a conductive disc rotor, or a new HTS disc motor, with conventional copper windings at its two iron semi-stators, and a HTS disc as a rotor. The conventional induction motor's operation principle is related with the induced electromotive forces in the conductive rotor. Its behaviour, characteristics (namely their torque?speed characteristics for different number of pole pairs) and modelling through Steinmetz and others theories are well known. The operation principle of the motor with HTS rotor, however, is rather different and is related with vortices' dynamics and pinning characteristics; this is a much more complex process than induction, and its modelling is quite complicated. In this paper, the operation was simulated through finite-elements commercial software, whereas superconductivity was simulated by the E-J power law. The Electromechanical performances of both motors where computed and are presented and compared. Considerations about the systems overall efficiency, including cryogenics, are also discussed.

In this paper, a poly-phase disc motor innovative feeding and control strategy, based on a variable poles approach, and its application to a HTS disc motor, are presented. The stator windings may be electronically commutated to implement a 2, 4, 6 or 8 poles winding, thus changing the motor's torque?speed characteristics. The motor may be a conventional induction motor with a conductive disc rotor, or a new HTS disc motor, with conventional copper windings at its two iron semi-stators, and a HTS disc as a rotor. The conventional induction motor's operation principle is related with the induced electromotive forces in the conductive rotor. Its behaviour, characteristics (namely their torque?speed characteristics for different number of pole pairs) and modelling through Steinmetz and others theories are well known. The operation principle of the motor with HTS rotor, however, is rather different and is related with vortices' dynamics and pinning characteristics; this is a much more complex process than induction, and its modelling is quite complicated. In this paper, the operation was simulated through finite-elements commercial software, whereas superconductivity was simulated by the E-J power law. The Electromechanical performances of both motors where computed and are presented and compared. Considerations about the systems overall efficiency, including cryogenics, are also discussed.

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