Search results for "scienza"
showing 10 items of 1408 documents
The continuous cooling transformation (CCT) as a flexible tool to investigate polymer crystallization under processing conditions
2009
An experimental route for investigating polymer crystallization over a wide range of cooling rates (from 0.01 to 1000◦C/s) and pressures (from 0.1 to 40 MPa) is illustrated, using a method that recalls the approach adopted in metallurgy for studying structure development in metals. Two types of experimental setup were used, namely an apparatus for fast cooling of thin films (100–200 μm thick) at various cooling rates under atmospheric pressure and a device (based on a on-purpose modified injection molding machine) for quenching massive samples (about 1–2 cm3) under hydrostatic pressure fields. In both cases, ex situ characterization experiments were carried out to probe the resulting struct…
Speckle Interferometry Analysis of Full-bending Behavior of GFRP Pultruded Material
2016
Abstract The use of Glass Fiber Reinforced Polymer materials (GFRP) has increased in the last years even among civil structural engineering due to their high specific strength, lightweight and excellent corrosion resistance. With application of the pultrusion method, the manufacture of large-scale profiles with various cross-section forms became potentially possible with relatively low costs. Usually two different technological approaches are available to realize the element: in the first one a mat-roving-mat sequence is adopted, in the second one only roving is present. Continuous filament mat (CFM, fibers distributed randomly in all directions) is often used to build up laminate thickness…
A DIC-based study of flexural behaviour of roving/mat/roving pultruded composites
2015
Abstract This paper reports a study of the flexural behaviour and resultant failure modes in E-glass/polyester pultruded composites. The digital image correlation (DIC) method is used to estimate the effect of fibre orientation on failure behaviour in thick beams, taking into account the presence of continuous filament mat layer (CFM) in the stacking sequence. In particular, the tests were carried out for specimens with off-axis angle of 0°, 7.5°, 15°, 30°, 45° and 90°. The crack initiation and the failure mechanisms depend on the mutual interaction between the stiffness properties of different areas in the stacking sequence. An influence index (I) was introduced to evaluate the magnitude o…
Experimental assessment of the shield-to-salt-fog properties of basalt and glass fiber reinforced composites in cork core sandwich panels applications
2018
Abstract In this paper, the effect of salt-fog exposition on the mechanical behavior of sandwich panels having cork agglomerate core was investigated. In particular, the aim of this research work is to assess the shield function of unidirectional basalt and E-glass reinforced polymer on the aging and failure mechanism of the core when such class of material are destined to operate in hostile environments (e.g., marine environment). To do this, the manufactured sandwich panels were exposed up to 60 days to salt-fog environment, according to ASTM B 117 standard. Unaged and aged specimens were analyzed through three point bending tests after aging time of 10, 25 and 60 days. Digital Image Corr…
Il Filtro Integrale Auto-Regressivo Continuo (I-ARC) per l’Analisi di Strutture Esposte al Vento
2010
In questo studio viene proposto un metodo per la rappresentazione di processi aleatori Gaussiani e stazionari, utile a modellare la turbolenza della velocità del vento, introducendo la versione integrale del modello auto-regressivo discreto già proposto in precedenza. La rappresentazione di un processo aleatorio di assegnata funzione di correlazione viene condotta integrando un’equazione integro-differenziale in cui viene coinvolto un nucleo, che rappresenta la memoria del processo, in presenza di un rumore bianco Gaussiano. La soluzione dell’equazione rappresenta un campione del processo aleatorio della turbolenza della velocità del vento. E’ stato mostrato che il modello I-ARC fornisce, n…
Damage and plasticity at the interfaces in composite materials and structures
2009
Abstract The structural behavior at the interface between two surfaces of ductile, brittle or quasi-brittle materials is studied by a new analytical elastoplastic damaging model. The model is developed in the framework of a thermodynamically consistent theory. The Helmholtz free energy is written to predict the materials’ hardening or softening. An isotropic damage is considered and the possible effects of dilatancy are taken into account including non-associative flow rules. The interface laws are presented both in a rate and a discrete incremental form. The analytical formulation is then implemented into a finite element code and two structural members are studied to validate the model. T…
Il metodo genealogico e la morte di Dio nel pensiero di Friedrich Nietzsche
2022
L'obiettivo storico e teorico che ci prefiggiamo in questo contributo è quello di descrivere il ruolo del metodo genealogico all'interno della filosofia nietzscheana individuandone la stretta relazione con la concezione che il filosofo tedesco aveva della religione ed in particolare con l'idea della morte di Dio. Vedremo, infatti, come il metodo genealogico, lungi dall'essere soltanto una nozione appartenente al cosiddetto periodo illuministico, è ciò che realmente sottende a tutto il pensiero nietzscheano definendone i contorni e consentendo a Nietzsche, proprio in quanto metodo, di fornire una nuova visione del mondo e dell'uomo al suo interno. Inoltre, mostreremo come il concetto di mort…
On the moving loads problem in discontinuous homogeneous beams and layered beams with interlayer slip
This manuscript contains the main part of my research performed in this last triennium at the Department of Civil, Environmental, Aerospace and Materials Engineering, University of Palermo, and at the Department of Basic Sciences in Engineering Sciences (Unit of Applied Mechanics), University of Innsbruck, Austria. The research adheres to a common procedure of solving a scientistic problem. That is, introduction to the problem, selection of the mathematical and physical tools to model the problem, proposed solution, and numerical validation. The thesis proposes a novel modal superposition approach to the moving loads problem on discontinuous homogeneous beam and layered beam with interlayer…
Conditional Random Quantities and Compounds of Conditionals
2013
In this paper we consider finite conditional random quantities and conditional previsions assessments in the setting of coherence. We use a suitable representation for conditional random quantities; in particular the indicator of a conditional event $E|H$ is looked at as a three-valued quantity with values 1, or 0, or $p$, where $p$ is the probability of $E|H$. We introduce a notion of iterated conditional random quantity of the form $(X|H)|K$ defined as a suitable conditional random quantity, which coincides with $X|HK$ when $H \subseteq K$. Based on a recent paper by S. Kaufmann, we introduce a notion of conjunction of two conditional events and then we analyze it in the setting of cohere…
Transitive Reasoning with Imprecise Probabilities
2015
We study probabilistically informative (weak) versions of transitivity by using suitable definitions of defaults and negated defaults in the setting of coherence and imprecise probabilities. We represent \(\text{ p-consistent }\) sequences of defaults and/or negated defaults by g-coherent imprecise probability assessments on the respective sequences of conditional events. Finally, we present the coherent probability propagation rules for Weak Transitivity and the validity of selected inference patterns by proving p-entailment of the associated knowledge bases.