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Analisi strutturale in caso d'incendio di telai composti acciaio-calcestruzzo
No full textIn questo articolo si svolge un confronto tra metodologie di analisi avanzate e semplificate per la valutazione della sicurezza in caso d’incendio di strutture intelaiate composte acciaio-calcestruzzo, ponendo particolare attenzione all’influenza del criterio di progettazione sismico, delle curve e degli scenari d’incendio e delle diverse tipologie di sezioni delle travi composte sulla risposta strutturale in caso d’incendio
Performance under fire situations of concrete members reinforced with FRP rods: bond models and design nomograms
No full textIntuitively, the fire endurance of concrete members reinforced with fiber reinforced polymer (FRP) bars is related to the decrease in the mechanical properties of the materials concerned, especially resin. Large-scale fire tests recently performed on nine concrete slabs reinforced with glass FRP bars demonstrated the importance of bond between FRP and concrete for performance under fire situations. The experimental results showed that (1) the length of the FRP bars in the zone of slabs not directly exposed to fire (namely, anchoring length in fire situations) can be much more relevant to fire endurance than the concrete cover in the zone directly exposed to fire; and (2) the shape of the bar, for instance bent at the end, allows a reduction in anchoring length. From a design point of view, evaluating the necessary anchoring length through a bond model seems to be a key aspect. Full-scale test results, extensively presented elsewhere, are used in this paper to investigate the bond behavior of FRP bars embedded in concrete at high temperature and to assess a procedure to predict bond stress, slip, and load transfer at elevated temperature, based on both the results of numerical thermal analysis and the predictions of a bond theoretical model adjusted for fire situations. The design procedure outlined for calculating the minimal required anchoring length proves a valuable approach for the practicing engineer and stands together with the experimental and numerical results presented earlier. Finally, design nomograms are shown as examples of application of the procedure
Effetti delle alte temperature sulle prestazioni di solette di calcestruzzo armato con barre o griglie di FRP
No full textProve sperimentali in condizioni di incendio su solette di calcestruzzo armate con barre di FRP
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'Limoncella' apple, an Italian apple cultivar: Phenolic and flavonoid contents and antioxidant activity
No full text'Limoncella' is a variety of apple traditionally cultivated in south-central Italy since ancient Roman times. The relationship between phenolic composition and antioxidant activity of apple peel and flesh was investigated. Apple extracts analysed by high-performance liquid chromatography, showed that compared with flesh, peel was richer in all the quantified phenols. The most abundant polyphenols were the flavanols catechin and epicatechin, and the chalcones phloridzin and phloretin xyloglucoside. The extracts were evaluated for their radical-scavenging activity by the DPPH{radical dot} and H2O2 methods, and the antioxidant activity through reduction of Mo(VI) and inhibition of the formation of TBARS species. © 2007 Elsevier Ltd. All rights reserved
Isolation, characterization, and antioxidant activity of E- and Z-p-coumaryl fatty acid esters from cv. Annurca apple fruits
No full textA total of 12 fatty acid esters of Z- and E-p-coumaryl alcohol were isolated from cv. Annurca apple fruit and characterized. This apple variety is widely cultivated in the south of Italy, and the fruits typically undergoe a reddening treatment after harvest. Structures of the p-coumaryl esters were elucidated by GC-MS and 1H and 13C NMR after purification of individual compounds by HPLC. It was found that the esters are localized in the fruit peel. During reddening of the fruit, there was a substantial increase in the amount of esters and particularly in molecular species with unsaturated fatty acids. The individual compounds were tested for antioxidant activity, and over half were shown to be at least as effective as α-tocopherol. © 2005 American Chemical Society
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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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