1,706 research outputs found
America, Oceania e terre polari. manualetto di geografia per il ginnasio superiore
No full textAmerica, Oceania e terre polari : manualetto di geografia per il ginnasio superiore / Giuseppe Pardi. - Livorno : R. Giusti, 1927
Dedica manoscritta dell\u27autore: A Sua Eccellenza / Emilio Bodrero / omaggio di G. Pardi / Parma, 1 aprile 1927
https://galileodiscovery.unipd.it/discovery/fulldisplay?context=L&vid=39UPD_INST:VU1&search_scope=MyInst_and_CI&tab=Everything&docid=alma99000150018020604
Assessment of the residual life of corroded bridge beam
No full textRebar corrosion is one of the most common causes of deterioration of r.c. structures. The chemical attack, in fact, besides reducing the cross-section of the rebars, causes cracking in the concrete and delamination of the cover. It is therefore necessary to set up methods for the evaluation of the structural damage induced by corrosion, in order to estimate the residual load bearing capacity and then to plan the maintenance interventions. Aim of the paper is the development of general relationships between the corrosion level and the residual strength and ductility of r.c. bridge beams. On the basis of a great amount of results obtained by the authors and adopting conventional deterioration models, a procedure is proposed, suitable to estimate the life cycle of corroded structures. The proposed methodology is validated against ex-perimental results from literature and then applied to realistic cases for demonstration purposes
A simplified methodology for the evaluation of the residual life of corroded elements
No full textSteel corrosion is one of the most common causes of deterioration of reinforced concrete structures. In fact, the chemical attack causes cracking in the concrete and a number of related effects that weaken the capacity of the composite, as well as reducing the cross-section of the rebars. It is therefore extremely valuable to have methods targeted to the evaluation of the structural damage induced by corrosion for estimating the residual load bearing capacity of a structure, and then for planning the maintenance interventions. The aim of this paper is the development of a simplified methodology capable of providing conservative estimates of the residual life of corroded structures. Because of the great amount of results obtained by the authors, general relationships between the corrosion level and the residual strength and ductility of beams are derived, and their evolution is predicted using conventional deterioration models. The methodology proposed is validated using experimental results from literature
Electrochemical, Spectroscopic and Theoretical Studies of a Series of 1,1′-Ferrocene Dichalcogenido-Complexes of Rhodium and Iridium
No full textThe electrochemical behavior of a series of heterodimetallic 2-metalla-1,3-dichalcogena-[3]ferrocenophanes of general formula Cp∗(L)M[(EC5-H4)2Fe] (E = S, Se or Te; M = Rh, L = PMe3; M = Ir, L = PMe3, PPh3 or C≡NtBu) has been investigated. These complexes undergo two successive oxidation steps. In spite of the fact that both metal centres are potentially able to lose electrons, EPR spectra and theoretical considerations suggest that the bridging chalcogen atoms, which are centres of high electron density, also contribute significantly to the electron-removal processes
Effects of acidity on the insoluble polysaccharide content of germinating pollen of Pinus pinea L. and Pinus pinaster Aiton
No full textThe PAS reaction was used to slain total insoluble polysaccharides in pollen of two species of Pinus collected in two different years and germinated in vitro at different pH values. PAS-detectable polysaccharides are localized in the inline, cytoplasm and amyloplasts; PAS-undetectable (callose) in the middle of the intine, but only in the distal part of the grain. The total PAS stained polysaccharide content was quantified with a microdensitometer. Values are correlated with germination percentages and pollen tube length. The total polysaccharide content, as well as pollen tube length, varies in each species according to the year, probably due to environmental conditions. Also the various pHs deeply influence pollen germination and tube length, the lowest pH being the most unfavourable condition. At this pH (3.5) the total polysaccharide content is higher than in the control (pH 5.5): this is probably due to a lack of callose synthesis for tube wall or to a depolymerization of this polysaccharide, and a subsequent storage in a PAS-detectable form
Efficient Micropropagation by Ex Vitro Rooting of Myrtus communis L
No full textThis survey aims to develop a successful protocol through in vitro multiplication and ex vitro rooting of a native shrub, i.e., Myrtus communis L., in order to obtain the rapid production of large number of healthy plants. The in vitro proliferation showed how the two different genotypes (MR and MB) produced higher values in terms of shoot lengths, mean multiplication index (MMI) and number of nodes when treated with 6-benzylaminopurine (BAP) compared to the thidiazuron (TDZ) + 1-naphthalene acetic acid (NAA) combination. Concerning in vitro rooting, the experiment resulted in a high rooting rate (75%) and an average number of roots (5.13) by quickly dipping the basal portions in an indole-3-butyric acid (IBA) concentration of 3300 mg L-1, followed by transfer to a hormone-free growth medium (BM). In comparison, the other two concentrations tested (0.3 and 0.6 mg L-1) resulted in higher root length values. During the acclimatization phase, the study showed how the different treatments affected the development of the test shoots differently. In particular, shoots of both genotypes pre-treated by quickly dipping them in Clonex (R) to induce ex vitro rooting showed abundant root production only 10 days after the treatment compared to the in vitro rooting, in which roots were formed after 30 days. This suggests that ex vitro pre-treatment with Clonex (R) not only accelerates the rooting process compared to in vitro treatment, resulting in lower costs and easier processing, but also significantly increases root density, contributing to improved transplant success and plantlets quality. These results support the thesis that ex vitro rooting optimises plant propagation protocols, offering economic and practical advantages for nurseries and other propagation systems
A simplified methodology for the evaluation of the residual life of corroded elements.
No full textSteel corrosion is one of the most common causes of deterioration of reinforced concrete structures. In fact, the chemical attack causes cracking in the concrete and a number of related effects that weaken the capacity of the composite, as well as reducing the cross section of the rebars. It is therefore extremely valuable to have methods targeted to the evaluation of the structural damage induced by corrosion for estimating the residual load bearing capacity of a structure, and then for planning the maintenance interventions. The aim of this paper is the development of a simplified methodology capable of providing conservative estimates of the residual life of corroded structures. Because of the great amount of results obtained by the authors, general relationships between the corrosion level and the residual strength and ductility of beams are derived, and their evolution is predicted using conventional deterioration models. The methodology proposed is validated using experimental results from literature
Progetto Saggi: valutazione del comportamento sotto sisma di ponti e viadotti autostradali
No full text- …
