O reforço à flexão de vigas de betão armado tem apresentado uma evolução com tendência para soluções onde são utilizadas armaduras à base de materiais compósitos de fibras de Carbono, Vidro, Basalto ou Aramida, aplicadas com as técnicas Externally Bonded Reinforcement (EBR) ou Near Surface Mounted (NSM). No entanto, o comportamento elástico-linear destes materiais e as roturas tendencialmente frágeis das soluções condicionam a sua utilização em estruturas onde se pretende alguma ductilidade. Por conseguinte, procurou-se desenvolver um sistema de reforço estrutural alternativo e inovador em que os materiais de reforço aplicados, conjuntamente com a solução de reforço, conseguissem minimizar ou eliminar os riscos de roturas prematuras e ao mesmo tempo aumentassem a ductilidade dos elementos reforçados. Neste trabalho, apresenta-se em pormenor este novo sistema de reforço à flexão de vigas de betão armado com armaduras de aço inoxidável ancoradas internamente por aderência. Neste sistema de reforço as armaduras são contínuas e pós-instaladas pelo exterior, ficando as extremidades ancoradas por aderência no interior do elemento estrutural. Apresentam-se e discutem-se os resultados dos ensaios realizados para avaliar o desempenho das vigas de betão armado reforçadas com esta nova técnica. Os modos de rotura observados são também motivo de análise mais detalhada. Evidenciam-se alguns benefícios na utilização deste sistema de reforço inovador, nomeadamente ao nível da capacidade resistente última das vigas de betão armado e fazem-se algumas recomendações para a sua aplicação e utilização na reabilitação de elementos estruturais degradados.

A reabilitação de estruturas de betão armado com compósitos de FRP tem tido uma grande aceitação em especial devido às excelentes características de durabilidade dos materiais compósitos, ao seu baixo peso e às suas elevadas prestações mecânicas. Contudo, o comportamento elástico-linear dos compósitos de FRP e a sua forma de aplicação pode originar roturas prematuras, quer na técnica de reforço EBR (Externally Bonded Reinforcement), em que o compósito é colado externamente, quer na técnica NSM (Near Surface Mounted) em que o compósito é inserido na zona do recobrimento. No sentido de minimizar o risco de roturas prematuras e ao mesmo tempo aumentar a ductilidade dos elementos reforçados, desenvolveu-se um novo sistema de reforço estrutural em que as armaduras são ancoradas internamente por aderência. A fim de validar o novo sistema de reforço estrutural com compósitos de FRP foi realizado um programa experimental que incluiu o ensaio de vigas de betão armado (BA) reforçadas com as seguintes técnicas de reforço: EBR, NSM e pela nova técnica CREatE (continuous reinforcement embedded at ends). Neste artigo descrevem-se os ensaios experimentais realizados e analisam-se os resultados obtidos. As vigas de BA ensaiadas tinham seção em T, com um vão de 3,0 m e uma altura de 0,3 m e foram solicitadas em flexão em 4 pontos e testadas até a rotura. A técnica CREatE provou ser a mais eficaz das três alternativas testadas mobilizando a totalidade do CFRP e apresentando a maior capacidade resistente e a ductilidade mais elevada.

In this paper we revisit the Jackson exponentiality test. We study and provide functions in R language to compute theoretical moments, the distribution function and quantiles of the statistic test. Approximations to the exact distribution function and quantiles are also provided and their precision discussed. In addition, we provide an application of the Jackson test to real data.In this paper we revisit the Jackson exponentiality test. We study and provide functions in R language to compute theoretical moments, the distribution function and quantiles of the statistic test. Approximations to the exact distribution function and quantiles are also provided and their precision discussed. In addition, we provide an application of the Jackson test to real data.

Ever since Fibre Reinforced Polymers (FRP) began to be used in the repair or strengthening of structural elements, the premature debonding of the FRP composite from the substrate has been an important drawback that have been motive of several studies. The importance of knowing and describing the full-range behaviour of FRP-to-parent material interfaces rigorously is therefore urgent. However, at present, there are no analytical solutions that describe the full-range behaviour of such interfaces that help us to understand the full debonding phenomena of FRP-to-parent material interfaces free of any mechanical anchorage devices. Therefore, the aim of this study is to contribute the advances of that knowledge through an analytical solution by means of an exponential bond-slip model that is known to represent the nonlinearities involved in the debonding process of the FRP composite from the substrate. Analytical solutions for the slips, strains in the FRP composite, bond stress distributions along the bonded interface and stresses in the substrate are presented. A full-range load-slip analysis is also discussed.

Despite the number of applications with Carbon Fiber Reinforced Polymers (CFRP) have been grown in civil constructions, the studies available in the literature dedicated to the strengthening of old timber beams are very rare. This paper analyses the bending behaviour of old suspended timber floors flexurally-strengthened with CFRP laminates. A new bonding technique developed by the authors is presented which mainly consists on the embedding of both CFRP ends into the core of the timber beams. Differences between the traditional strengthening, i.e. Externally Bonded Reinforcement (EBR), and the new bonding technique are reported. A timber pavement without any CFRP laminate bonded to its soffit was also considered and the results were used as reference values for comparison with the strengthened specimens. The results revealed that the CFRP laminate used for the flexurally-strengthened of the specimen according to the EBR technique reached only 27.2% of the rupture strain of the CFRP laminate whereas the new bonding technique was capable to prevent the premature debonding of the CFRP from the timber substrate and the rupture of the CFRP laminate was observed. Furthermore, the strain distributions in the CFRP laminates and the bond stresses within the CFRP-to-timber interfaces were affected when the new technique was used. For the sake of better understanding the rupture modes observed, a numerical approach was developed which allowed us to conclude that, until the collapse of the beams, the timber never reached its yielding point and the collapse were mainly due to the poor quality of the timber (e.g. quantity of knot, cracks and irregular geometries) and the low shear capacity of the beams.

We report a new chelonioid turtle on the basis of a nearly complete skull collected in lower Paleocene, shallow marine deposits, equivalent to the offshore Landana Formation, near the town of Landana in Cabinda Province, Angola. Chelonioid material previously reported from this locality is likely referable to this new taxon. The well-preserved skull is missing the left quadrate, squamosal, and prootic, both opisthotics, and the mandible. The skull possesses a rod-like basisphenoid rostrum, which is a synapomorphy of Chelonioidea, but it differs from other chelonioid skulls in that the contact between the parietal and squamosal is absent, and the posterior palatine foramen is present. Phylogenetic analysis recovers the new taxon as a basal chelonioid. The Paleocene– Eocene strata near Landana have produced a wealth of turtle fossils, including the holotype of the pleurodire Taphrosphys congolensis. A turtle humerus collected from the Landana locality differs morphologically from the humeri of chelonioids and Taphrosphys, indicating the presence of a third taxon. Chelonioid fossil material in the Landana assemblage is rare compared to the abundant fragmentary remains of Taphrosphys that are found throughout the stratigraphic section. This disparity in abundance suggests the new chelonioid taxon preferred open marine habitats, whereas Taphrosphys frequented nearshore environments.

In this note we consider the monoid $PODI_n$ of all monotone partial permutations on $\{1,\ldots,n\}$ and its submonoids $DP_n$, $POI_n$ and $ODP_n$ of all partial isometries, of all order-preserving partial permutations and of all order-preserving partial isometries, respectively. We prove that both the monoids $POI_n$ and $ODP_n$ are quotients of bilateral semidirect products of two of their remarkable submonoids, namely of extensive and of co-extensive transformations. Moreover, we show that $PODI_n$ is a quotient of a semidirect product of $POI_n$ and the group $\mathcal{C}_2$ of order two and, analogously, $DP_n$ is a quotient of a semidirect product of $ODP_n$ and $\mathcal{C}_2$.

We report a new chelonioid turtle on the basis of a nearly complete skull collected in lower Paleocene, shallow marine deposits, equivalent to the offshore Landana Formation, near the town of Landana in Cabinda Province, Angola. Chelonioid material previously reported from this locality is likely referable to this new taxon. The well-preserved skull is missing the left quadrate, squamosal, and prootic, both opisthotics, and the mandible. The skull possesses a rod-like basisphenoid rostrum, which is a synapomorphy of Chelonioidea, but it differs from other chelonioid skulls in that the contact between the parietal and squamosal is absent, and the posterior palatine foramen is present. Phylogenetic analysis recovers the new taxon as a basal chelonioid. The Paleocene– Eocene strata near Landana have produced a wealth of turtle fossils, including the holotype of the pleurodire Taphrosphys congolensis. A turtle humerus collected from the Landana locality differs morphologically from the humeri of chelonioids and Taphrosphys, indicating the presence of a third taxon. Chelonioid fossil material in the Landana assemblage is rare compared to the abundant fragmentary remains of Taphrosphys that are found throughout the stratigraphic section. This disparity in abundance suggests the new chelonioid taxon preferred open marine habitats, whereas Taphrosphys frequented nearshore environments.

We report a new chelonioid turtle on the basis of a nearly complete skull collected in lower Paleocene, shallow marine deposits, equivalent to the offshore Landana Formation, near the town of Landana in Cabinda Province, Angola. Chelonioid material previously reported from this locality is likely referable to this new taxon. The well-preserved skull is missing the left quadrate, squamosal, and prootic, both opisthotics, and the mandible. The skull possesses a rod-like basisphenoid rostrum, which is a synapomorphy of Chelonioidea, but it differs from other chelonioid skulls in that the contact between the parietal and squamosal is absent, and the posterior palatine foramen is present. Phylogenetic analysis recovers the new taxon as a basal chelonioid. The Paleocenetextendash Eocene strata near Landana have produced a wealth of turtle fossils, including the holotype of the pleurodire Taphrosphys congolensis. A turtle humerus collected from the Landana locality differs morphologically from the humeri of chelonioids and Taphrosphys, indicating the presence of a third taxon. Chelonioid fossil material in the Landana assemblage is rare compared to the abundant fragmentary remains of Taphrosphys that are found throughout the stratigraphic section. This disparity in abundance suggests the new chelonioid taxon preferred open marine habitats, whereas Taphrosphys frequented nearshore environments.

A novel linear analog adder is proposed only with n-type enhancement IGZO TFTs that computes summation of four voltage signals. However, this design can be easily extended to perform summation of higher number of signals, just by adding a single TFT for each additional signal in the input block. The circuit needs few number of transistors, only a single power supply irrespective of the number of voltage signals to be added, and offers good accuracy over a reasonable range of input values. The circuit was fabricated on glass substrate with the annealing temperature not exceeding 200° C. The circuit performance is characterized from measurements under normal ambient at room temperature, with a power supply voltage of 12 V and a load of ≈ 4 pF. The designed circuit has shown a linearity error of 2.3% (until input signal peak to peak value is 2 V), a power consumption of 78 μW and a bandwidth of ≈ 115 kHz, under the worst case condition (when it is adding four signals with the same frequency). In this test setup, it has been noticed that the second harmonic is 32 dB below the fundamental frequency component. This circuit could offer an economic alternative to the conventional approaches, being an important contribution to increase the functionality of large area flexible electronics. © 2016 IEEE.

The study and assessment of Power Quality issues is nowadays a very important subject, particularly regarding Cyber-physical and Industrial Agents based systems, which are extremely sensitive to Power Quality disturbances. Giving students or engineers practical experience in this field requires a large investment from teaching institutions. This paper presents a laboratory device that emulates Power Quality disturbances in order to provide the required experimental expertize in the subject. It addresses limiting aspects such as harmonic distortion, flicker, sags, swells and transients. The developed system presents a good opportunity for technicians, even without deep knowledge on the field of power quality, to learn basic principles and be able to identify Power Quality events. Since the system is based on real data, represents a valuable approach giving trainees practical knowledge on the field.