9,213 research outputs found
Contributi allo sviluppo di modelli idrologici accoppiati previsionali e Montecarlo
No full textA careful management of the environment and of water resources requires modern eco-hydrological models which allow the evaluation of flood events and of the response natural systems, especially in a context of accelerated environmental changes due to human activities and climate change. Modelling such complex dynamics requires mathematical tools, such as modern hydrological response models, rainfall stochastic models and meteorological models. In the present thesis the research activities have been focused on coupling physically-based hydrological models and models which prescribe relevant hydro-meteorological forcings on the basis of predictions (meteorological models) or probabilistic representations of statistical features of climate variables (weather stochastic generators).
A geomorphological model of the hydrological response applied to a number of relevant case studies is here developed. The use of a reliable flood forecasting model is extremely beneficial to prevent extreme events because of its capability to predict the behaviour of a hydrological system under different initial and boundary conditions. The hydrological model implemented constitutes a robust basis for the study and the development of coupled meteorological and hydrological models. Special attention is devoted to the analysis of high-resolution rainfall fields which are forecasted by a LAM meteorological model (ETA model); spatial and temporal analyses are carried out to test the main characters of precipitation forecasts.
Hydrological, ecological and water resources applications need as forcing input weather time series with a suitable spatial and temporal detail.
Measured ground-based meteorological data are often inadequate, particularly because of their limited length which may lead to a mis-representation of extreme events. Stochastic weather generators are a viable technique for simulating time series consistent with the statistical characters of observed data. In this thesis a new stochastic model is developed, based on a multivariate autoregressive framework. The objective is the generation of a coherent set of hydro-meteorological variables including maximum and minimum air temperature, maximum and minimum air humidity, atmospheric pressure, daily mean wind velocity and direction and the meteorological tide component for a given geographic location. These variables are required to force models applied to coastal hydrological systems, where the presence of a tidal component is important in determining the response to ordinary and extreme events (e.g. as in the important case of the Venice Lagoon). However, the daily resolution is not detailed enough to describe the meteorological tidal level fluctuations in usual hyrologic applications; a down-scaling technique is thus applied in order to obtain hourly time series of simulated tidal levels. The results highlight the model capability to reproduce the main statistics both at daily and hourly resolution. Moreover the stochastic generator is able to well reproduce observed extreme events frequencies
Fracture toughness of synthesized high-performance epoxies subject to accelerated water aging
No full textVideo reproducing the internal stresses induced by swelling during the Hydrothermal Aging of a DGEBA+DDS and a DGEBF+DDS epoxy systems.
The video shows photoelastic isochromatic fringes acquired in red light from a circular dark field polariscope.
Samples shown are bulk beams and Single Edge Notched Bending beams (compliant with ASTM D 5045).
The video is linked in the paper Journal "Fracture toughness of synthesised high-performance epoxies subject to accelerated water aging" by Giuseppe Pitarresi, Sabina Alessi and Andrea Toscano
Fracture toughness of synthesized high-performance epoxies subject to accelerated water aging
No full textVideo reproducing the internal stresses induced by swelling during the Hydrothermal Aging of a DGEBA+DDS and a DGEBF+DDS epoxy systems.
The video shows photoelastic isochromatic fringes acquired in red light from a circular dark field polariscope.
Samples shown are bulk beams and Single Edge Notched Bending beams (compliant with ASTM D 5045).
The video is linked in the paper Journal "Fracture toughness of synthesised high-performance epoxies subject to accelerated water aging" by Giuseppe Pitarresi, Sabina Alessi and Andrea Toscano
Andrea Bacová
No full textAndrea Bacová focuses on research and teaching in the field of residential architecture. Her work includes systematic research on residential buildings and their urban context. She actively participates in promoting Slovak architecture and is the author of several publications and exhibitions
Fracture toughness of synthesised high-performance epoxies subject to accelerated water aging
No full textThe effects of water uptake on the fracture toughness of epoxy systems with high glass-transition temperatures (Tgabove 170 °C) are investigated. Aging conditioning has been conducted in hot water, followed by a desorption conditioning in a room temperature dry-airborne. Water aging determines plasticisation effects and crosslink-density modifications, revealed by reductions of the Tg. It is less known how such modifications influence the material fracture toughness. In this study, Single Edge Notched Bending samples have been tested according to standards, to evaluate the KICfracture toughness at different stages of water absorption-desorption. The characterisation has been supported by Photoelastic Stress Analysis, allowing to evaluate stresses induced by swelling during aging. Results indicate that swelling stresses activate a crack closure mechanism that might contribute to the observed increase of the measured fracture toughness during water absorption, but are ineffective at saturation. Two epoxy systems, one based on DGEBA and the other on DGEBF, having different cross-link densities, have been studied. The plasticisation achieved at saturation translated into a significant increase of fracture toughness only in DGEBA, while fracture toughness measured at other conditioning stages was likely influenced by internal swelling stresses and sample pre-cracking strategy
Pressurized CNTs under tension: a finite-deformation lattice model
No full textWe propose a finite-deformation lattice model for carbon nanotubes (CNTs), in which an energetic cost is assigned to changes in bond lengths, bond angles, and dihedral angles, while atomic interactions are governed by a Reactive Empirical Bond-Order potential. For the first time, we consider the effect of severe traction and pressure applied simultaneously, with the ultimate goal of understanding how material properties are affected by such loads. In particular, the radial stiffness and the axial stiffness have been investigated: on making use of the second generation Brenner potential, we have found that peculiar transitions softening-hardening-softening occur in both the radial and axial stiffness, a behavior that could be compared with the ones observed in experiments or predicted by ab initio methods. The constitutive response described here can be exploited in the design of CNT-based hydrogen storage systems, and it opens a new possibility for tuning material properties, in order to make CNTs softer or harder in a controlled way
Viewer-, Author-, and Ownership in the Work of Andrea Zittel
No full textAndrea Zittel invites others to collapse the distinctions between artist, viewer, and collaborator by interacting with her usable works. This thesis explores the process of interacting with Zittel\u27s works, and how it affects viewer-, author- and ownership
The Lettere of Andrea Calmo: authorial artifices and historical reality
No full textopenNonostante l’edizione di Vittorio Rossi del 1888, la raccolta di "ingegnosi cheribizzi" e di "fantastiche fantasie" di Andrea Calmo è ancora avvolta da un certo mistero. L’autore, dissimulando la propria identità dietro alla “maschera” dell’umile pescatore veneziano, è stato in grado di offrire uno spaccato della cultura e della società nella Venezia cinquecentesca.
In particolare, è il quarto libro delle Lettere ad aver suscitato maggiore interesse tra gli studiosi ed i lettori: pubblicato nel 1566, a diversi anni di distanza dai primi tre, questo libro si distingue per il fatto che tutte le epistole sono indirizzate a delle donne immaginarie o realmente esistite.
In questa sede si propone, in primo luogo, uno studio della biografia del Calmo accompagnata da un’analisi del contesto storico-culturale della Venezia cinquecentesca; in secondo luogo, invece, viene proposto un commento di alcune lettere dell’ultimo libro dell’opera calmiana, che cerchi di far luce principalmente sull’aspetto linguistico e contenutistico del testo.Despite Vittorio Rossi's 1888 edition, Andrea Calmo's collection of "ingegnosi cheribizzi" and "fantastiche fantasie" is still shrouded in a certain mystery. The author, dissimulating his own identity behind the "mask" of the humble Venetian fisherman, was able to offer a cross-section of culture and society in sixteenth-century Venice.
In particular, it is the fourth book of the Letters that has aroused greater interest among scholars and readers: published in 1566, several years after the first three, this book stands out for the fact that all the epistles are addressed to women imaginary or actually existed.
Here we propose, first of all, a study of Calmo's biography accompanied by an analysis of the historical-cultural context of sixteenth-century Venice; secondly, however, a commentary on some letters from the last book of Calmo's work is proposed, which seeks to shed light mainly on the linguistic and content aspect of the text
- …
