Search results for " SCIENZA"

Creep Behavior of Poly(lactic acid) Based Biocomposites

2017

Polymer composites containing natural fibers are receiving growing attention as possible alternatives for composites containing synthetic fibers. The use of biodegradable matrices obtained from renewable sources in replacement for synthetic ones is also increasing. However, only limited information is available about the creep behavior of the obtained composites. In this work, the tensile creep behavior of PLA based composites, containing flax and jute twill weave woven fabrics, produced through compression molding, was investigated. Tensile creep tests were performed at different temperatures (i.e., 40 and 60 °C). The results showed that the creep behavior of the composites is strongly inf…

Toward the Decarbonization of Plastic: Monopolymer Blend of Virgin and Recycled Bio-Based, Biodegradable Polymer.

2022

Decarbonization of plastics is based on two main pillars: bio-based polymers and recycling. Mechanical recycling of biodegradable polymers could improve the social, economic and environmental impact of the use of these materials. In this regard, the aim of this study was to investigate whether concentrations of the same recycled biopolymer could significantly affect the rheological and mechanical properties of biodegradable monopolymer blends. Monopolymer blends are blends made of the same polymers, virgin and recycled. A sample of commercially available biodegradable blend was reprocessed in a single-screw extruder until two extrusion cycles were completed. These samples were exposed to gr…

Surface Modified Arundo Donax Natural Fibers for Oil Spill Recovery

2021

The use of green materials for oil recovery applications is the goal to be achieved to reduce the environmental impact of these essential processes. In this context, Arundo Donax L. is a plant known for its wide uses whose absorbent properties have been previously investigated. In this paper, the influence of silane surface treatment on the absorbent behavior of natural fibers extracted from the culms of this eco-friendly and cost-effective material was assessed. A close correspondence has been identified between the physical characteristics of the investigated oil and the fiber size, by means of microstructural and morphological analysis. Excellent results have been achieved with an absorp…

PLLA-BASED SCAFFOLDS FOR OSTEOCHONDRAL TISSUE REGENERATION VIA THERMALLY INDUCED PHASE SEPARATION TECHNIQUE

L’ingegneria tessutale (TE) è una scienza multidisciplinare che mira a progettare e sviluppare sostituti biologici per migliorare, riparare e/o sostituire i tessuti negli organismi umani. Sulla base della tipica triade dell’ingegneria tessutale è incentrato il primo capitolo Scaffold, Source and Signal; lo scaffold funge da struttura tridimensionale, le cellule rappresentano la source mentre il bioreattore fornisce gli adeguati segnali chimico/fisici. In questo lavoro di tesi sono stati presi in considerazione tutti e tre questi aspetti avendo come obiettivo la rigenerazione osteocondrale. La guarigione dei difetti osteocondrali, riguardanti le lesioni della cartilagine che si esten- dono f…

Elezioni 2013: la crisi del "bipolarismo imperfetto" (ed. ampliata e aggiornata)

2015

Questo articolo analizza l'interazione tra sistema elettorale e sistema partitico nel caso italiano confrontando i risultati delle elezioni politiche nel 2006, 2008 e 2013. A partire dall'osservazione dei diversi risultati delle elezioni politiche del 2006 e del 2008, da un lato, e del 2013, dall'altro, l’articolo dedica attenzione a come tra i sistemi elettorali e di partito non vi sia un nesso causale sistematico, ma una "interazione di reciproca indipendenza". Le prime due elezioni politiche, svoltesi in base alla legge elettorale del 2005, hanno portato a un mantenimento del sistema bipolare. Il terzo, al contrario, ha portato a un ripristino del sistema multipolare. Tali risultati dive…

Preparation and characterization of polyolefin- based nanocomposite blown films for agricultural applications

2009

Polyolefin-based films were prepared in the presence of two different organo-modified clays and characterized. The influence of organo-modifier and matrix composition on film morphology and properties were investigated using SEM, XRD, UV-Vis, FT-IR, contact-angle measurements and mechanical tests. The filler increased the films' rigidity and tear strength. Transparencies were almost unchanged in the visible range, but were reduced for harmful radiation. The presence of the clay increases the greenhouse effect, i.e. it hinders the passage of thermal emission from the soil to the outer part of the greenhouse during the night. The wettability of the materials was not influenced by the presence…

A stress ribbon footbridge as the tie of an arch bridge.

2008

Revisited mixed-value method via symmetric BEM in the substructuring approach

2012

Abstract Within the Symmetric Boundary Element Method, the mixed-value analysis is re-formulated. This analysis method contemplates the subdivision of the body into substructures having interface kinematical and mechanical quantities. For each substructure an elasticity equation, connecting weighted displacements and tractions to nodal displacements and forces of the same interface boundary and to external action vector, is introduced. The assembly of the substructures is performed through both the strong and weak regularity conditions of the displacements and tractions. We obtain the solving equations where the compatibility and the equilibrium are guaranteed in the domain Ω for the use of…

A damage identification procedure based on Hilbert transform: Experimental validation

2010

SUMMARY This paper aims at validating the feasibility of an identification procedure, based on the use of the Hilbert transform, by means of experimental tests for shear-type multi-degree-of-freedom systems. Particularly, a three-degree-of-freedom frame will be studied either numerically or experimentally by means of a laboratory scale model built at the laboratory of the Structural, Aerospace and Geotechnical Engineering Department (DISAG) of University of Palermo. Several damage scenarios have been considered to prove the effectiveness of the procedure. Moreover, the experimental tests have been conducted by considering two different input loads: pulse forces, simulated by means of an ins…

Damage identification by Lévy ant colony optimization

2010

This paper deals with the identification of incipient damage in structural elements by non-destructive test based on experimentally measured structural dynamical response. By applycation of the Hilbert transform to the recorded signal the so-called phase of the analytical signal is recovered and a proper functional is constructed in such a way that its global minimum gives a measure of the damage level, meant as stiffness reduction. Minimization is achieved by applying a modified Ant Colony Optimization (ACO) for continuous variables, inspired by the ants’ forageing behavior. The modification consists in the application of a new perturbation operator, based on alpha stable Lévy distribution…