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Opis: In these last twenty years a new sensibility for the seismic themes around buildings has emerged from a cultural and technical point of view. As a result of some earthquakes happened in Italy, the promulgation of technical codes has accelerated and, essentially, the standards of Eurocodes were accepted. Consequently, also in the field of historical buildings, a set of specific guidelines have been issued. In the current state of art, designers are faced with many methods of calculation which the technical codes offer for the assessment of the seismic vulnerability of historical buildings. Designers can use simplified or complex approaches which assume different starting hypothesisto obtain different results. This thesis aims to investigate the various aspects that the designer meets during the study of the static behaviour of an historical building and the assessment of its seismic vulnerability. A study case is also proposed which regards a Venetian Villa of the XVIth Century located in “Riviera del Brenta” near Venice, with a critical comparison of the results obtained by the application of the various methods of calculation. The thesis begins with an outline of the historical development of seismic technical codes in Italy and shows how the sensibility has developed in the Italian culture. In particular it is illustrated the difference between the approach of the legislation "a posteriori" (where a “patchy zoning” was generally performed after the occurrence of earthquakes), and the probabilistic approach based on the peaking ground acceleration expected in every Italian site. The Second and the Third Chapters contain the analysis of the current seismic legislations and in particular the guidelines for historical buildings. The Chapter 4 provides a general discussion on the masonry and the definition of the mechanical parameters. There are many critical aspects relating to a characterization of models which can realistically represent the historical masonry. They are due to a heterogeneity of variables such as, for instance, the mechanical parameters, the physiological behaviour, the connections, etc. In the Chapter 5 the basic concepts of seismic behaviour of historical buildings are discussed. In particular the Pagano’s classification of masonry buildings is illustrated with special regard of the following factors: stiffness of horizontal structures; efficiency of “masonry beams”; efficiency of intersection between walls. From the Chapter 6 the analysis of the study case begins. Here we can find the description of the Venetian Villa (historical evolution of the buildings, description of geometrical characteristics, structural behaviour, etc. In the Chapter 7, the first level of analysis is performed for the study-case. The method of calculation is contained in the guidelines for historical buildings. A critical discussion of the results is also illustrated. In the Chapter 8 is performed a linear kinematic analysis based on various possible kinematic mechanisms identified through the study of cracking and the lacks of the structural connections. The Chapter 9 shows a non-linear static analysis (pushover) for the study-case which refers to two limit behaviour models: the first one with infinitely rigid diaphragms and efficient masonry beams; the second one based on infinitely flexible diaphragms and weak masonry beams. The results are compared and critically discussed. In the same way the Chapter 10 and 11 perform a linear static analysis and a linear dynamic analysis for the two models of the Chapter 9, so the results can be compared. In the last Chapter a general discussion about all the results of the performed analysis is conducted. Here the work points out the conceptual limits of each method of calculation and the possibility of use related to the objectives which must be reached. Finally some design indications related to the results of the analysis are illustrated.
Ključne besede: Seismic, Vulneraility, Analitical, Methodologies
Objavljeno v RUNG: 02.07.2020; Ogledov: 2849; Prenosov: 41
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Opis: A major environmental pollution problem is the release into the atmosphere of particulate matter, including nanoparticles (NPs), which causes serious hazards to human and ecosystem health, particularly in urban areas. However, knowledge about the uptake, translocation and accumulation of NPs in plant tissues is almost completely lacking. The uptake of silver nanoparticles (Ag-NPs) and their transport and accumulation in the leaves, stems and roots of three different tree species, downy oak (Quercus pubescens Willd.), Scots pine (Pinus sylvestris L.) and black poplar (Populus nigra L.), were assessed. In the experiment, Ag- NPs were supplied separately to the leaves (via spraying, the foliar treatment) and roots (via watering, the root treatment) of the three species. Uptake, transport and accumulation of Ag were investigated through spectroscopy. The concentration of Ag in the stem was higher in the foliar than in the root treatment, and in poplar more than in oak and pine. Foliar treatment with Ag-NPs reduced aboveground biomass and stem length in poplars, but not in oaks or pines. Species-specific signals of oxidative stress were observed; foliar treatment of oak caused the accumulation of H2O2 in leaves, and both foliar and root treatments of poplar led to increased O2− in leaves. Ag-NPs affected leaf and root bacteria and fungi; in the case of leaves, foliar treatment reduced bacterial populations in oak and poplar and fungi populations in pine, and in the case of roots, root treatment reduced bacteria and increased fungi in poplar. Species-specific mechanisms of interaction, transport, allocation and storage of NPs in trees were found. We demonstrated definitively that NPs enter into the tree stem through leaves faster than through roots in all of the investigated tree species.
Ključne besede: Ag-NPs, pathway of uptake, Pinus sylvestris L., Populus nigra L., Quercus pubescens Willd.
Objavljeno v RUNG: 20.04.2020; Ogledov: 2901; Prenosov: 0
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Opis: The growing demand of consumers for environment-friendly and safe food products already forced many winemakers to restrict the application of synthetic fungicides to earlier season, trying to reduce the risk of residues being detected in wines. Main risk for infection by B. cinerea, however, occurs later in the season. To support an improvement in whole-season B. cinerea green care, the potential of yeasts as biocontrol agent (PBA) was studied. Selected yeasts were tested for their antifungal activities. Furthermore, a field experiment in Pinot noir and Pinot gris vineyards was designed to study different combinations of optimized canopy microclimate manipulation (CMM) techniques and PBA application. In experimental conditions, PBA's ability to maintain appropriate population density for disease prevention was observed. Grape and wine quality parameters were evaluated. Analytical approach of metabolomics was applied to upgrade the understanding of potentially induced changes in plant metabolism. Based on yeasts testing results, biocontrol yeast P. guilliermondii ZIM 624 was selected and after its field application, we were able to detect its suitable density on grapes until harvest. In case of early defoliation for both varieties smaller grape compactness was confirmed together with lower yield. Among grape basic quality parameters, optimized techniques showed positive effect on sugar content, but unexpectedly, in the treatments with biocontrol yeasts the trends toward higher acidity were noticed in Pinot gris. CMM and PBA introduction indicated some effects on grapevine biosynthetic behaviour but the differences in content of these metabolites compared to control were poorly detected in final wines with exception of mainly some flavonols, stilbenes and flavan-3-ols (and consequently total phenolic content).
Ključne besede: sustainable viticulture, Botrytis cinerea, yeasts, biocontrol, canopy microclimate manipulation, metabolomics, grapevine metabolites
Objavljeno v RUNG: 28.02.2020; Ogledov: 3811; Prenosov: 0
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Ključne besede: funghi, resistence, viticulture
Objavljeno v RUNG: 22.01.2020; Ogledov: 3068; Prenosov: 0
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Ključne besede: free-electron lasers, harmonic generation
Objavljeno v RUNG: 15.01.2020; Ogledov: 2996; Prenosov: 91
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