47,186 research outputs found
Design spectra to be used in Base Isolation Design in light of recent strong motion records
No full textStrong motion records have shown an increase of the maximum values of PGA and PGV, also associated to the increase of the archived strong motion records. Nowadays, the worldwide largest PGA values are: 3,94g (vertical) and 2,75g (horizontal), from the 2008 Iwate-Miyagi and 2011 Tohoku earthquakes, while the current PGV maxima are larger than 2.0 m/s (horizontal and vertical). These unforeseen values have encouraged a more conscious approach in BIS design, being necessary to move to larger design periods and to face wider design displacements. Many changes have occurred in the history of BIS, as indicated in Design Recommendations for Seismically Isolated Buildings by AIJ (2016), tracing the improvements of BIS in Japan, and in De Luca and Guidi (2019). In this excursion, a significant contribution has been given by Miyazaki (2008) that defined a "Next Generation of seismic isolation" to counteract the unprecedented spectral values of displacement and acceleration. In this perspective, the paper analyzes the acceleration, velocity and displacement spectra of different sets of strong motion records to provide suggestions for seismic design of base-isolated structures in the light of higher spectral values. In particular, we will consider: the set defined in Trevor Kelly (2001), that divided motions into pre-1971 and post-1971; the set of FEMA307 (1999), in which three categories of ground motion are considered (short duration, long duration and forward directivity); the set used by Miyazaki (2008) for the Next Generation of Seismic Isolation; the set defined by Suzuki and Iervolino (2017) to trace the history of largest PGA and PGV; the set used by De Luca and Guidi (2019) to trace the improvements in BIS design and propose a classification of BIS in three successive generations. A comparison between results, for different periods, will lead to possible design indications for BIS
Seasonal Fluctuations of Crop Yield, Total Phenolic Content and Antioxidant Activity in Fresh or Cooked Borage (Borago officinalis L.), Mallow (Malva sylvestris L.) and Buck’s-Horn Plantain (Plantago coronopus L.) Leaves
No full textThe interest for wild edible plants as functional food is increasing among consumers in the Mediterranean countries because of their high content of antioxidants. However, a critical point is the seasonality of wild edible species due to their spontaneity and the cultivation results necessary to satisfy market requests. Moreover, cooking may be necessary for most wild edible species to enhance their palatability. In the present experiment, the crop yield, total phenolic content (TPC) and antioxidant activity (AA) of leaves were determined in three wild edible species (Borago officinalis L., Malva sylvestris L. and Plantago coronopus L.), which were hydroponically cultivated in winter and in spring. Plants were recurrently harvested three times and the leaves were analyzed raw or after boiling in water for different times based on their palatability as evaluated by a hedonic test (2 min for B. officinalis, 2.5 min for M. sylvestris and 8 min for P. coronopus). The total crop yield was promising, especially for P. coronopus, with small differences between winter and spring (9.3 and 13.8 kg m−2, respectively). The boiling treatment caused a loss of TPC and, in some cases, of the AA in B. officinalis and M. sylvestris due to the solubilization of phenolic and other antioxidant compounds in boiling water. Conversely, in P. coronopus, TPC and AA were higher in boiled leaves than in fresh leaves, likely due to the strong binding of phenolic compounds to the cell wall. This binding might lead to the inefficient extraction of these compounds through the boiling treatment
Pierre Guidi, Jean-Luc Martineau et Florence Wenzek (dir.) (2024) - L\u27école en mutation
No full textReviewed: Pierre Guidi, Jean-Luc Martineau, Florence Wenzek (eds.), L’école en mutation. Politiques et dynamiques scolaires en Afrique (années 1940-1980), Toulouse, Presses universitaires du Midi, 2024, 138 p.Recensé : Pierre Guidi, Jean-Luc Martineau, Florence Wenzek (dir.), L’école en mutation. Politiques et dynamiques scolaires en Afrique (années 1940-1980), Toulouse, Presses universitaires du Midi, 2024, 138 p
Presentazione di profili di velocità prodotti da un nuovo sistema Doppler Multicanale
No full textshort communication su videocassetta a cura del Centro Didattico Televisivo dell’Università di Firenze, Presentata a International Symposium on Acoustical Imaging, 199
Effects of the simultaneous presence of geometrical and velocity broadening on the pulsed Doppler spectrum
No full textInvariance of the Doppler bandwidth with range cell size above a critical beam-to-flow angle
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