196,756 research outputs found
RCFST COLUMNS EXPOSED TO FIRE: NON-STANDARD THERMAL TEST AND “HOT” COMPRESSION TEST RESULTS DISCUSSION
No full textThis paper presents a discussion on the experimental results of the “hot” condition compres-sion test performed on full-scale fire-exposed, Reinforced Concrete-Filled Steel Tubes (RCFST) and Rein-forced Concrete (RC) short columns (outer diameter 457 mm and length 1600 mm). In the companion papers, full details about the test procedure, thermal field, load-displacement curves are provided. In particular, that research work presents the results of five tests for thermal field measurements, that consider four specimens heated in a gas furnace in standard fire conditions (ISO 834) and one specimen heated in an electric furnace in non-standard conditions; the results of six axial compressive tests are also giv-en. In this paper, the results of non-standard thermal tests and a “hot” condition compression test are discussed. Also, numerical-experimental and analytical-experimental comparisons are proposed for non-standard thermal tests and the “hot” condition compression test, respectively
Structural characterization for the seismic protection of heritage churches
No full textThe high vulnerability of ancient masonry churches and their condition of cultural heritage assets make their seismic protection a complex operation. Structural analysis offers valuable support, but requires a realistic modelling of the building structure. Acquiring a thorough knowledge of the building constructional characteristics is, therefore, fundamental and may be achieved combining information from different sources. Besides regular surveying operations and limited diagnostic tests, other tools are available to obtain a detailed picture of the situation. For the case of churches, that often are many centuries old and have evolved with several structural changes during their lifetime, a historical research aimed at the reconstruction of the different phases of the building transformation is extremely useful to point out its characteristics, and possibly its hidden criticalities. A different but equally useful contribution comes from the recently developed high-power software tools for 3D modelling, allowing to visualize the shape of the asset but also to understand in detail its geometry and its building process. The combination of these two very different means offers a deep insight of the building features. Three Italian heritage churches testify here the positive results achieved by a synergic use of different knowledge sources, and in particular with crossing documental information and direct inspection supported by effective representation tools
Second-harmonic generation as a source of nonclassical light
No full textWe investigate the transformation of light statistics due to a second-harmonic generation process and address a quantum perturbative approach to retrieve the moments of the output light distribution for given input light states
Conditional measurements with silicon photomultipliers
No full textNonclassical states of light can be efficiently generated by performing conditional measure-ments. An experimental setup including Silicon Photomultipliers can currently be implemented for this purpose. However, these devices are affected by correlated noise, the optical cross talk in the first place. Here we explore the effects of cross talk on the conditional states by suitably expanding our existing model for conditional measurements with photon-number-resolving detectors. We assess the nonclassicality of the conditional states by evaluating the Fano factor and provide experimental evidence to support our results
Effect of cross-talk on conditional measurements performed with multi-pixel photon counters
No full textWe investigate the role of the optical crosstalk in the conditional measurements performed on quantum states of light. In particular, we analyze how the statistics of the conditional states are affected by cross-talk by retrieving their first and second moments and we test the sub-Poissonianity of the state by evaluating the Fano factor
A visual servoing algorithm based on epipolar geometry
No full textA visual servoing algorithm for mobile robots is proposed. The main feature of the algorithm is that it exploits object profiles rather than solving correspondence problems using object features or texture. This property is crucial for mobile robot navigation in unstructured environments where the 3D scene exhibits only surfaces whose main features are their apparent contours. The framework is based on the epipolar geometry, which is recovered from object profiles and epipolar tangencies. Special symmetry conditions of epipoles are used to generate the mobile robot control law. For the sake of simplicity, mobile robot kinematics is assumed to be holonomic and the camera intrinsic parameters are assumed partially known. Such assumption can be relaxed to extend the application field of the approach
Seismic Behaviour of Masonry Vault-Slab Structures
No full textSpandrel walls typically play a structural role in masonry buildings, transferring load from a slab to the supporting vault. Some indications are given in the literature on the behaviour
of spandrels under the effect of vertical loads, but little attention is given to the effect coming from lateral forces acting on the building. An opportunity to investigate this problem has come
from the need of analyzing a monumental building which was damaged by the Nov. 24, 2004 Val Sabbia earthquake in the north of Italy. The finite element model set up for the analysis of
the vault-spandrel-slab system is presented and the structural role resulting for the spandrels is discussed
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