In this paper, we address the solution of the symmetric eigenvalue complementarity problem (EiCP) by treating an equivalent reformulation of finding a stationary point of a fractional quadratic program on the unit simplex. The spectral projected-gradient (SPG) method has been recommended to this optimization problem when the dimension of the symmetric EiCP is large and the accuracy of the solution is not a very important issue. We suggest a new algorithm which combines elements from the SPG method and the block active set method, where the latter was originally designed for box constrained quadratic programs. In the new algorithm the projection onto the unit simplex in the SPG method is replaced by the much cheaper projection onto a box. This can be of particular advantage for large and sparse symmetric EiCPs. Global convergence to a solution of the symmetric EiCP is established. Computational experience with medium and large symmetric EiCPs is reported to illustrate the efficacy and efficiency of the new algorithm.

Die Ausweitung von Robotertechnologien nicht nur in der Industrie, sondern zunehmend auch in Dienstleistungsbereiche, stellt große Herausforderungen an die Mensch-Roboter-Kollaboration. Der Artikel beleuchtet psychologische, soziologische, arbeitswissenschaftliche und berufspädagogische Gesichtspunkte bei der Gestaltung und dem Einsatz von Robotern in Produktion und Service. Zu diesem Zweck werden zunächst spezifische Merkmale der Mensch-Roboter-Interaktion dargestellt, um anschließend Prinzipien der Funktionsteilung zwischen Menschen und Robotern in Arbeitssystemen des Produktions- und Servicebereichs zu diskutieren. Zu berücksichtigen sind hier die Organisation gesellschaftlicher Arbeit, die spezifischen Arbeitsaufgaben sowie die Möglichkeiten und Grenzen der informationstechnischen Realisierung solcher Aufgaben. Der Artikel endet mit dem Plädoyer, bei der Entwicklung und Anwendung von Robotern arbeitswissenschaftliche Kriterien mit Ansätzen partizipativer Technikgestaltung zu kombinieren.

In this note, we consider the semigroup $O(X)$ of all order endomorphisms of an infinite chain $X$ and the subset $J$ of $O(X)$ of all transformations $\alpha$ such that $|Im(\alpha)|=|X|$. For an infinite countable chain $X$, we give a necessary and sufficient condition on $X$ for $O(X) = < J >$ to hold. We also present a sufficient condition on $X$ for $O(X) = < J >$ to hold, for an arbitrary infinite chain $X$.

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Neste artigo apresentam-se e analisam-se um conjunto de ensaios realizados em vigas de betão armado reforçadas com armaduras pós-instaladas de aço ou de FRP, incluindo os referentes a uma nova técnica (CREatE) desenvolvida na FCT NOVA. Os resultados experimentais permitiram concluir que a técnica CREatE possibilita aumentos de resistência e ductilidade consideráveis face às técnicas tradicionais.

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Abstract Strengthening of concrete structures with a new concrete layer has been commonly used for columns, beams and slabs. This technique is economic and efficient for structural strengthening since it uses the same base materials, steel and concrete. It is usually applied on the compressed face of the concrete element due to concrete’s recognized behaviour under compression, posing several challenges to control cracking and resistance when applied on the tensile face. For assessing the performance of the strengthening method, twelve slab specimens were designed and tested monotonically. The main parameters to assess in this work were the debonding behaviour and load, and the relationship between the latter and the relative displacements at the interface of the two concrete layers. The performance of the strengthened structures strongly relies on the interaction of the two concrete layers, with this being the main subject of the research about overlaid concrete. The load transfer capacity of the interface depends on the interface shear strength, which in turn is highly dependable on substrate roughness, cleanliness and curing conditions of the newly added layer. Interface performance may be improved by using steel connectors crossing the interface, properly anchored on both layers. The importance for these elements grows as the existing concrete is more deteriorated, since adhesion strength will decrease with lower quality concrete. This paper presents the experimental research for the application of bonded concrete overlays on the tensile face of reinforced concrete slabs, mainly aimed at office buildings and parking facilities, where spatial clearances or inaccessibility to the lower side of the slabs are recurrent. A ductile behaviour upon debonding was achieved for the specimens with reinforcement crossing the interface, and a debonding load up to three times that of the reference specimens without reinforcement crossing the interface.

Abstract Pipelines and piping components may experience large cyclic deformations during a reduced number of cycles (Ni = 1�100 cycles), when subjected to extreme cyclic loading events (e.g. hurricanes, support settlements, earthquakes). In accordance with these loading scenarios, a lateral movement can be applied to the pipeline inducing bending stresses that gradually promotes strain localization, due to progressive plastic instabilities (buckling), damage evolution and final failure. This work aims at characterizing ultra-low cycle fatigue (ULCF) behaviour of the \{X52\} piping steel under bending and local buckling state. An experimental program was carried out to derive \{ULCF\} data for smooth, notched and flat-grooved specimen geometries under cyclic bending. Furthermore, the small-scale tests were simulated in ABAQUS� with the objective of computing the parameters governing the fatigue damage models. The classical Coffin-Manson strain-life relation commonly used in the low cycle fatigue (LCF) regime is proposed to model the fatigue lives. In addition, the Xue model, particularly dependent of the monotonic fracture strain was also used for the prediction of the number of cycles until the crack initiation. The numerical data obtained with these models are compared, being achieved similar fatigue lives predictions for notched plane specimens. For the case of flat-grooved specimens which provides plain strain conditions, an overestimation from the Coffin-Manson relation was observed while the Xue model reproduces very good results for both specimens' series.

The Urban-Architect role in smart cities is a topic that has not received much attention from the scientific community. This article studies the work of the traditional responsible for thinking the cities, the Urban Architect. Under a critical proposition, aspects of this problematic are identified, which is in part nourished by the deficient action of these professionals.
The study was divided into two parts, the first one materialized through a bibliographical survey, in this section it is presented; 1 - a more detailed description of why this research work; 2 - a contextualisation of the transition of the scenarios is explained; 3 - the problematization and the reflection are raised for some reasons of the "disqualification" of the action of the architect-urbanist in the scene.
The second is based on the discussion between the authors and case studies; 4 - aspects are discussed and some characteristics are listed for "(re) framing" within the ideal scenario; 5 - four case studies are described: two smart cities built from scratch and two cities being transformed into smart cities; 6 - the limitations, conclusions and strands for future work are woven.

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Abstract This paper proposes an experimental study aiming to evaluate stress intensity factors (SIFs) for fatigue cracks propagating under pure mode I and mixed-mode I+II for a S235 structural steel. Compact tension (CT) specimens with a side hole were manufactured in order to generate a stress field, ahead of the crack tip, resulting in mixed-mode fatigue crack propagation. Specimens with distinct side hole locations were submitted to fatigue tests under stress controlled conditions for a stress rati

A set of three old suspended timber floors were flexurally strengthened with carbon fiber–reinforced polymer (CFRP) strips in order to investigate the effectiveness of externally bonding FRP to their soffits. The specimens were from an old building and 740-mm-wide bands were transferred to the laboratory in order to be tested in a four-point bending test. One specimen was tested with no strengthening system and the results obtained were used as reference values for comparison with the specimens that were externally bonded and reinforced (EBR) with CFRP strips. Two similar EBR systems were studied: (1) keeping both ends of the CFRP strips free of any restriction (traditional technique), and (2) embedding both ends of the CFRP strips into the timber, thus providing a bonding anchorage of the strips (new technique). The installation of the new strengthening system comprises the opening of holes in the timber and the creation of a transition curve between the holes and the timber surface. This transition curve allows a smooth transition of the CFRP laminate between the hole and the timber surface, thus avoiding stress concentrations in this area. After the opening of the holes, the resin is applied inside the hole and on the beam surface, and then the CFRP laminate is mounted. The load-carrying capacity of the specimens, the rupture modes, and the strains and bond stress distributions within the CFRP-to-timber interface are presented. A nonlinear numerical simulation of the specimens based on the midspan cross-sectional equilibrium is also presented. The results showed that the use of the new strengthening system enhances the performance of the specimens when compared with the traditional strengthening system.