Search results for " MATERIALI"
showing 10 items of 710 documents
Synthesis, Structural Analysis, Fiber Formation and Preliminary Anticancer Characterization of the Organotin Polyether from Dibutyltin Dichloride and…
2012
The organotin polyether derived from reaction of dibutyltin dichloride and 2,5-dimethyl-3-hexyne-2,5-diol was rapidly synthesized employing classical interfacial polymerization in 65% yield and a chain length of 360 units. IR results are consistent with the polyether structure. Bands characteristic of the formation of the Sn-O are present and bands characteristic of the Sn-Cl are absent. F MALDI MS results in the low mass range gives ion fragment clusters to five units. Isotopic abundance matches for tin are consistent with its presence in these ion fragment clusters. In the high mass range ion fragment clusters to greater than 300 units are found. The products offer outstanding inhibition …
ARCHITETTURA SISTEMICA. MATERIALI ED ELEMENTI COSTRUTTIVI (III EDIZIONE AGGIORNATA E CON ILLUSTRAZIONI A COLORI)
2011
Questa terza edizione di Architettura Sistemica, rispetto alla seconda del 2010 che introduceva illustrazioni a colore, poggia ancora sulla struttura del testo elaborato nella prima edizione e sulla stessa veste grafica. Ma abbiamo constatato che talune questioni, anche se di uso limitato, erano state tra- lasciate e che, al contrario, altri concetti ed espressioni della cultura tecnologica in questi ultimi anni hanno assunto un’in- discussa rilevanza. Pertanto l’edizione attuale si propone di integrare e ag- giornare il testo con tre questioni particolari. La prima si riferisce ai materiali di nuova generazione, riferibili alle nanoscienze e alle nanotecnologie, che stanno provocando un sa…
The effects of water absorption and salt fog exposure on agglomerated cork compressive response
2022
The replacement of synthetic foams with agglomerated cork in sandwich composites can meet the increasing environmental concerns. Its peculiar morphology and chemical composition lead to outstanding dimensional recovery that endorsed a broad investigation of its compressive behavior. The knowledge of neat material response is fundamental to obtain a reliable design dataset, but it is necessary to consider all the environmental factors (water, moisture and sunlight) that significantly modify material mechanical properties. In view of this, the present work investigates the effect of distilled and seawater absorption and salt fog exposure on the compressive behavior of two agglomerated corks w…
Evaluation of aging behavior under salt-fog spray conditions of green sandwich structures
2018
In this paper, the aging resistance of sandwich structures made with cork agglomerate as core and flax-reinforced polymeric laminates as face sheets was investigated for the first time. In order to evaluate their durability in a hostile environment, a sandwich plate was manufactured by vacuum bagging technique and aged under salt-fog spray conditions, according to ASTM B 117 standard. The evolution of the sandwich mechanical properties during the aging exposition was analyzed by carrying out quasi-static flexural tests and Charpy impact tests both on unaged specimens and on specimens aged for 10, 25, and 60 days, respectively. The quasi-static experimental results showed that despite the sa…
Dynamic Mechanical Behavior Analysis of Flax/Jute Fiber-Reinforced Composites under Salt-Fog Spray Environment
2020
Over the last decades, natural fiber-reinforced polymer composites (NFRPs) gained great attention in several engineering fields thanks to the reduction of the environmental impact and the end-of-life cost disposal. Unfortunately, the use of NFRPs is limited, mainly due to their weak resistance against humid environments. Since limited literature is available about the evolution of the dynamic mechanical response of NFRPs under aggressive environments, this paper aims to investigate the damping properties of flax, jute and flax/jute epoxy composites exposed to salt-fog up to 60 days. Furthermore, sodium bicarbonate fiber treatment was performed to improve the composites&rsquo
Karl Marx: dalla filosofia dell'autocoscienza alla filosofia della prassi
2018
The interpretation of the philosophical thought of Karl Marx given in the second half of the twentieth century canonically distinguishes between the works of the youth period and those of the maturity. Even if only a few interpreters have supported the thesis of the existence of “two Marx”, one opposed to the other, the attention given to some posthumous writings (the Critique of the Hegelian Philosophy of Public Law and the Economic and Philosophic Manuscripts of 1844 in particular) inevitably led to neglect the writings of the younger Marx. However, the years spent in Berlin (1836-41) are decisive, both for the experience gained alongside the young Hegelians and for the discovery of philo…
Materiali ibridi a base di nanotubi di allosite per la rimozione d’inquinanti
2017
L’allosite (HNT) è un interessante materiale argilloso allumino-silicato naturale, non tossico e biocompatibile, con la caratteristica forma tubolare cava dotata di parziale carica positiva interna e negativa esterna.Combinando le peculiarità di un composto organico con le proprietà di un materiale inorganico, è possibile ottenere sistemi ibridi organici–inorganici con interessanti proprietà e vasti campi di applicazione. Sono un esempio delle “nanospugne” capaci di adsorbire efficacemente potenziali inquinanti. In questo contesto sono stati preparati, dei materiali ibridi “spugna” costituiti da unità ciclodestriniche e allosite e ancora un sistema ibrido HNT-Cucurbit[8]uril. Il primo possi…
Templated growth of smart nanocomposite thin films: Hybrid aerosol assisted and atmospheric pressure chemical vapour deposition of vanadyl acetylacet…
2009
Hybrid aerosol assisted and atmospheric pressure chemical vapour deposition methodology has been utilised to produce nanocomposite thin films of gold nanoparticles and vanadium dioxide from vanadyl acetylacetonate and auric acid. The addition of tetraoctyl ammonium bromide (TOAB) to the precursor Solution gave control of the size and distribution of gold nanoparticles in the vanadium oxide matrix. These reactions led to vanadium dioxide films with reduced crystallite sizes and enhanced thermochromic properties. The films were analysed by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. Their optical and thermochromic behaviour was also determined, This h…
ECO-FRIENDLY MATERIALS FOR THE ENERGY RETROFIT OF EXISTING BUILDINGS
2015
Today is widely recognized that the main cause of CO2 production and of non-renewable energy consumptions in Europe is due to the building field. For this reason, to improve the energy performance of existing houses through an energy retrofit action (adapting their performances to those required by regulations) is an important strategy to reduce energy consumptions since they are much more than new ones, also representing an economic opportunity. In particular, an important approach in the reducing energy needs consists in the thermal insulation of the envelope, through the application of innovative technologies and materials. The paper will present the result of a research about the possib…
Core-shell Zn-doped TiO2-ZnO nanofibers fabricated via a combination of electrospinning and metal-organic chemical vapour deposition
2010
Zn-doped TiO2 nanofibers shelled with ZnO hierarchical nanoarchitectures have been fabricated combining electrospinning of TiO2 (anatase) nanofibers and metal-organic chemical vapor deposition (MOCVD) of ZnO. The proposed hybrid approach has proven suitable for tailoring both the morphology of the ZnO external shell as well as the crystal structure of the Zn-doped TiO2 core. It has been found that the Zn dopant is incorporated in calcined electrospun nanofibers without any evidence of ZnO aggregates. Effects of different Zn doping levels of Zn-doped TiO2 fibers have been scrutinized and morphological, structural, physico-chemical and optical properties evaluated before and after the hierarc…