Search results for "Materiali"
showing 10 items of 876 documents
A new eco-friendly chemical treatment of natural fibres: Effect of sodium bicarbonate on properties of sisal fibre and its epoxy composites
2016
Abstract Several researchers have shown how sisal fibres possess remarkable tensile properties that yield them good candidates as reinforcement in biocomposite materials. This work aims to evaluate the effect of an eco-friendly and cost effective surface treatment method based on the use of commercial sodium bicarbonate (i.e. baking soda) on properties of sisal fibre and its epoxy composites. In particular, raw sisal fibres were treated with a 10%w/w of sodium bicarbonate solution for different periods (24, 120 and 240 h), at room temperature. Changes occurring in sisal fibres were characterized through scanning electron microscope, Fourier transform infrared spectroscopy, thermogravimetric…
Artichoke (Cynara cardunculus L.) fibres as potential reinforcement of composite structures
2011
Abstract The aim of this paper is to examine the use of artichoke fibres as potential reinforcement in polymer composites. The fibres are extracted from the stem of artichoke plant, which grows in Southern Sicily. In order to use these lignocellulosic fibres as potential reinforcement in polymer composites, it is fundamental to investigate their microstructure, chemical composition and mechanical properties. Therefore, the morphology of artichoke fibres was investigated through electron microscopy, the thermal behaviour through thermogravimetric analysis and the real density through a helium pycnometer. The chemical composition of the natural fibres in terms of cellulose, lignin, and ash co…
Solid state 13C-NMR methodology for the cellulose composition studies of the shells of Prunus dulcis and their derived cellulosic materials.
2020
Lignocellulosic fibers and microcellulose have been obtained by simple alkaline treatment from softwood al- mond shells. In particular, the Prunus dulcis Miller (D.A.) Webb. was considered as a agro industrial waste largely available in southern Italy. The materials before and after purification have been characterized by 13C CPMAS NMR spectroscopy methodology. A proper data analysis provided the relative composition of lignin and holo- cellulose at each purification step and the results were compared with thermogravimetric analysis and FT-IR. To value the possibility of using this material in a circular economy framework, the fibrous cellulosic material was used to manufacture a handmade c…
Combining in the melt physical and biological properties of poly(caprolactone) and chlorhexidine to obtain antimicrobial surgical monofilaments.
2012
Bacterial infections on a sutured wound represent a critical problem, and the preparation of suture threads possessing antimicrobial properties is valuable. In this work, poly(caprolactone) (PCL) monofilaments were compounded at the concentration of 1, 2 and 4 % (w/w), respectively, to the antiseptic chlorhexidine diacetate (CHX). The incorporation was carried out in the melt by a single-step methodology, i.e. “online” approach. Mechanical tests revealed that the incorporation of CHX does not significantly change tensile properties of PCL fibres as the thermal profile adopted to prepare the compounded fibres does not compromise the antibacterial activity of CHX. In fact, CHX confers to comp…
Effect of environmental conditions on the durability of polycarbonate for the protection of cultural heritage sites.
2019
Polycarbonate is a good material for covering and protecting cultural heritage sites because of its durability, mechanical properties, and transparency. However, polycarbonate degrades under environmental weathering with a significant decrease of physical and mechanical properties and loss of transparency. In this work, the contemporary presence of ultraviolet irradiation and different temperature and moisture conditions have been taken into account to study the environmental degradation of this polymer with regard to its mechanical and optical properties. The photo-oxidation reactions cause a decrease in the molecular weight and the formation of many oxygenated species. The hydrolytic sci…
Torsional shear strength and elastic properties of adhesively bonded glass-to-steel components
2020
Nowadays glass is widely used in building applications and coupled to steel through adhesive joining. Reliable mechanical characterization of these joints is necessary to design and predict the final structure performance.In this framework, the aim of this paper is to measure the pure shear strength and elastic modulus for design and modelling of adhesive joined glass-to-steel structures.Torsional shear strength and elastic properties of an adhesively bonded glass-to-steel component were measured on several joined steel-to-steel and steel-to-glass samples.An epoxy resin-based adhesive was used as joining material for AISI304 steel and soda-lime glass.The same steel and adhesive were used to…
Towards new paradigms in tourism fields: an anthropological perspective
2018
The present notes of research centres on the problem of fragmentation, which is experienced by tourism applied research in the recent years. Echoing the original claims issued by John Tribe –followed by many others scholars–, we discuss further on the socio-economic factors that prevented tourism its maturated and stylised form. Though we introduce a materialist viewpoint, echoing David Harvey, no less true is that the point is open to further debate, incorporating cultural viewpoints. The impulses and bursts of interest received simultaneously from social science but also by the theory of scientifisation coined by Jafar Jafari did not suffice to gain purchase over a maturated discipline. E…
Locale/Globale. Laboratorio: il regionalismo critico. Tradizionale/Innovativo. Materiali e tecnologie costruttive ecologiche
2011
Sembra che parlare di architettura sia divenuto ormai solo il pretesto per innescare dibattiti cui partecipano, da una parte, i sostenitori di una opinione e dall'altra i sostenitori della opinione opposta, interagendo in una sorta di talk-show televisivo dove è prassi lo scontro di opinioni. Tuttavia il confronto è l'unica strategia perseguibile in cui è possibile ritrovare la soluzione idonea alle necessità e ai cambiamenti che la naturale o violenta mutazione impone all'uomo oggi.
Novedad revolucionaria y filosofía materialista (hacia la unificación teórica de marxismo y psicoanálisis)
2010
Tras exponer y explicar, en la Introducción y en el Primer capítulo, los límites que encuentra la filosofía de la ciencia a la hora de explicar la producción de descubrimientos revolucionarios en el campo de las ciencias (sobre todo, después de la intervención post-positivista de Kuhn, Lakatos, etc. contra la epistemología positivista y neo-positivista); tras exponer y explicar, a su vez, cómo estos mismos límites de comprensión no pueden ser superados ni siquiera cuando la filosofía de la ciencia recurre a los contenidos de las ciencias sociales, como ocurre en la actualidad (a la psicología y a la sociología, tal y como éstas se definen en sociedad liberal); tras exponer y explicar estos …
Reflexions crítiques sobre alguns problemes epistemològics del materialisme dialèctic [Pròleg]
2004
Les sotragades pendulars de la història sempre són perilloses, especialment quan es tracta d'aspectes ideològics i teòrics: un determinat període pendular pot generar actituds dogmàtiques i inquisitorials o, en altres casos, d'ignorància i rebuig. I ara ens trobem al bell mig d'aquest perill. ~ensorrament a Europa de l'anomenat socialisme real pot provocar l'arraconament d'anys i anys de reflexió i estudi al voltant dels problemes plantejats per Marx, Engels i Lenin; centenars de milers de pàgines impreses podrien passar a ocupar racons ben amagats de les biblioteques fins que d'aquí a un grapat d'anys, quan canviés el període pendular, fossen rescatades i desempolsades per recuperar si més…