1,721,129 research outputs found
The Influence of Shape Memory Alloy Ties on the Seismic Behaviour of Historical Masonry Buildings
No full textAn innovative tying technique based on the use of shape memory alloys has been developed. It entails the interconnection of outside masonry walls and floors with shape memory alloy devices that, exploiting the highly non-linear super-elastic behaviour of said alloys, can control the forces transmitted to the wall while allowing the wall a certain leeway of deformation. The force vs. displacement behaviour of the devices can be easy adapted to different design requirements owing to the high modularity of elements composition. Shaking table tests on models of historical brick masonry walls indicate that by using shape memory alloy devices instead of steel bars to tie walls there is significant improvement in seismic behaviour
Progress of Application , R&D and Design Guidelines for Shape Memory Alloy Devices for Cultural Heritage Structures in Italy
No full textMortar Deterioration of the Masonry Walls in Historical Buildings. A Case History: the Vanvitelli's Mole in Ancona
No full textShake table testing and numerical modelling of a steel pallet racking structure with a seismic isolation system
No full textThis study aims to evaluate the performance of a steel storage pallet racking system equipped with a novel seismic isolation system, which is effective along the cross-aisle direction alone. The isolation system consists of two IsolGOODS® isolators, which are curved surface slider bearings as framed into the European Standards for anti-seismic devices. The efficiency of the proposed device in reducing the seismic effects on pallet racks is investigated. Firstly, uniaxial real-time shake table tests are performed, showing a great reduction of floor accelerations. With the help of a herein validated numerical model, advanced knowledge is obtained. Six accelerograms, two normal-fault records, two pulse-like, and two spectrum-compatible series are selected for drawing generally valid statements. As proposed in this work, the outcomes confirm that the isolation system provides substantial reduction in terms of floor accelerations. In contrast, no up-lift of the base-connections is recorded: the uprights are always engaged in compression. On the whole, the most severe condition comes from the pulse-like record (Emilia 2012), in which displacement demand must be carefully considered while defining the isolators to be put in place
Demo-application of shape memory alloy devices: The rehabilitation of the S. Giorgio Church Bell-Tower
No full textThis paper describes the rehabilitation of the S. Giorgio Church Bell-Tower (Trignano, Municipality of S. Martino in Rio, Reggio Emilia, Italy), completed in September 1999. This masonry building, seriously damaged by the earthquake of October 15th 1996 which struck the Reggio Emilia and Modena Districts (Italy), was investigated by the authors immediately after the seismic event, as other ancient Cultural Heritage Structures (CUHESs) in the same area. In the past, seismic events have visited substantial destruction that translates into a significant loss of architectural heritage. The most common solution traditionally used to enhance the CUHESs seismic behaviour is the introduction of localized reinforcements, usually Traditional Steel Ties (TSTs), increasing stability and ductility. Anyway, in many cases said reinforcement techniques, often too invasive, proved to be inadequate to prevent collapse. For these reasons, the Bell-Tower intervention applies Innovative Antiseismic Techniques (IATs) by the use of superelastic Shape Memory Alloy (SMA) Devices (SMADs), a technology developed after a large amount of theoretical studies, numerical analyses and test campaigns. The SMADs, which can be considered a powerful tool with respect to the traditional methods, provide acceleration reduction, force limitation and energy dissipation. Furthermore, they are characterized by low invasivity and complete reversibility. When another earthquake occurred on June 18th 2000, with the same epicenter and a comparable Richter Magnitudo, the Bell-Tower, subjected to a new investigation, showed no damage of any type. Thus, the new seismic event has been the best verification of the retrofit intervention. © 2001 SPIE - The International Society for Optical Engineering
Artificial neural network based on SQUIDs: demonstration of network training and operation
No full textWe propose a scheme for the realization of artificial neural networks based on
superconducting quantum interference devices (SQUIDs). In order to demonstrate the
operation of this scheme we designed and successfully tested a small network that implements
an XOR gate and is trained by means of examples. The proposed scheme can be particularly
convenient as support for superconducting applications such as detectors for astrophysics,
high energy experiments, medicine imaging and so on
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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