1,190 research outputs found
Hybrid phosphorus-doped silica architectures derived from a multistep sol-gel process for improving thermal stability and flame retardancy of cotton fabrics
No full textHybrid phosphorus-doped silica architectures have been prepared through sol-gel processes in order to enhance the thermal stability and flame retardancy of cotton. To this aim, diethylphosphatoethyltriethoxysilane has been used as a functional phosphate alkoxysilane in a multistep process, consisting of consecutive depositions for obtaining architectures with a different number of layers (namely, 1, 3 or 6 layers). The role of such architectures has been deeply investigated and correlated with the final properties of the treated fabrics. FT-IR ATR spectroscopy has been exploited for assessing the formation of the silica skeleton on the cotton surface and for evaluating the interactions between the cellulosic fibres and the doped film. The sol-gel treatments have proved to play a protective role on the degradation of the cotton fibres, hindering the formation of volatile species that fuel the further degradation and favouring the formation of char
The Right to the City: Mobility of Proximity and Social Inclusion of Elderly People
No full textThat to the city is a fundamental right that emphasises the importance of people’s access to the opportunities of urban life, including essential services and cultural activities. This contribution argues that mobility of proximity and walkability are essential components of spatial justice, with particular attention to enhancing elderly people’s quality of life. Different strategies to develop more walkable urban environments will be identified through the construction of design scenarios. Facing the challenges that elderly people encounter in walking throughout the city is crucial when urban infrastructural elements are taken into consideration, while solutions acting at a softer level (social and participatory activities), to be effective, should promote walkability for all members of society, regardless of their age or other specific conditions
Muoversi in città. Accessibilità e mobilità nella metropoli contemporanea
No full textIl volume presenta i risultati di uno studio che analizza il modo in cui la localizzazione di aree residenziali, beni e servizi, combinata con il differente possesso di capitale di mobilità da parte dei residenti, ne influenzi gli stili di mobilità, l'accessibilità e il livello di inclusione sociale. La prima parte, teorica, descrive la relazione che esiste tra mobilità, accessibilità ed equità sociale; la seconda, empirica, analizza in termini interdisciplinari e comparati l'interazione tra localizzazione residenziale, stili di mobilità e accesso a beni e servizi nelle aree metropolitane di Bologna, Milano e Torin
Use of FBG sensors for monitoring cracks of the equestrian statue of Bartolomeo Colleoni in Venice
No full textThe Bartolomeo Colleoni monument suffered for years damage from the local climate. The process of restoring the Colleoni equestrian statue, started in 2003, allowed to understand how the bronze statue was originally cast and manufactured and the techniques used in its construction. During this process a relevant crack on the right foreleg was investigated in correspondence of the cast-on joining the right foreleg to the front portion of the horse body. The crack was investigated experimentally by Fiber Bragg Grating (FBG) sensors, avoiding any modelling because of the very complex structure of the statue. An array of FBG sensors connected in series was glued on the crack with the aim of capturing live information about the effect of applying stress on the crack opening. The monitoring system was successfully tested during repositioning of the RIDER on the horse and is available for long term inspection of the crack opening evolution
Sol-gel derived architectures for enhancing cotton flame retardancy: effect of pure and phosphorus-doped silica phases
No full textPure and phosphorus-doped silica phases derived from sol-gel processes have been investigated, aiming to assess any enhancement of the thermal and fire stability of cotton fabrics. Indeed, it has already been shown that the combustion behaviour of cellulosic substrates can be strongly affected by the presence of a protective phosphorus-rich silica coating. Thus, in the present work, the performances of coatings consisting of pure silica and phosphorus-doped silica have been investigated and compared by using thermogravimetry and combustion tests (more specifically, resistance to an irradiative heat flux and to a flame application). The results show that the thermal and thermo-oxidative stability of cotton, as well its resistance to an irradiative heat flux of 35 kW/m2, have been enhanced by the deposited coating, irrespective of the presence of phosphorus. However, the best results have been achieved exploiting the joint effect of thermal shielding (exerted by the silica phase) and char-forming (as a consequence of the phosphoric acid source present in the alkoxysilane precursor). On the other hand, only pure silica coatings, despite their very low add-on, have proven to protect cotton from the application of a methane flame for 5 s, favouring the formation of a thermally stable residu
Phosphorus- and nitrogen-doped silica coatings for enhancing the flame retardancy of cotton: synergisms or additive effects?
No full textIn the present work, the synergistic or additive effects due to the concurrent presence of phosphorus- and/or nitrogen-based compounds on the flame retardancy of cotton fabrics previously treated by sol-gel processes have been thoroughly investigated. Indeed, although additives containing P and/or N structures have been exploited for imparting fire resistance to cellulosic substrates, the quantification of their synergistic level has not been fully considered. More specifically, the concept of "synergistic effectiveness" has been applied to cotton fabrics treated with a phosphorus-doped silica coating, further doped with a bisphosphonate, melamine or urea. Flammability and cone calorimetry tests have shown that only phosphorus (i.e. bisphosphonate) is able to promote a certain synergism with the sol-gel derived oxide phases in terms of residue, heat release rate and total burning time
Presentazione. Per una mobilità sostenibile
No full textIl contributo introduce il volume risultato di una ricerca Prin su accessibilità e mobilità svolta nelle aree metropolitane di Milano, Bologna e Torino. Viene sottolineato lo sprawl urbano come tendenza che ha portato a una maggiore mobilità e, di conseguenza, a un maggiore impatto ambientale e a un aumento del tempo dedicato agli spostamenti; una tendenza non sostenibile sotto tutti i punti di vista. Viene quindi evidenziata la necessità di un modello di sviluppo diverso rispetto a quello che ha favorito la suburbanizzazione; di quest'ultima viene peraltro ricostruita brevemente la storia, a partire dai suoi inizi negli Stati Uniti. Una mobilità sostenibile, pertanto, può solo passare da una lotta allo sprawl, in quanto questo rende di fatto inevitabile un massiccio ricorso all'automobile e pressochè impossibile un servizio capillare di trasporto pubblico
Photocatalytic properties and optical characterization of cotton fabric coated via sol-gel with non-crystalline TiO2 modified with poly(ethylene glycol)
No full textTiO2 thin film coatings were realized on cotton fabrics by sol–gel technique using titaniumiso-propoxide. The effect of different starting acidic solutions (nitric, hydrochloric and acetic acids) and the addition of poly(ethylene glycol) onto two different (0.25 M and 0.025 M) concentrations of TiO2 have been widely investigated. The applications of the sol were performed by pad-dry-curingmethod at 120 °C for 5 min for curing condition. The microstructural, morphological and optical properties and the photocatalytic activity of the films were investigated. In particular, XRD analysis showed a thin film deposition without any crystalline structure, which was also confirmed by Tauc plot analysis with a band gap from3.3 to 3.5 eV. The photocatalytic activity assessment, evaluated by degradation of Procion red PX4B dyestuff, was carried out by visible and UV (365 nm) sources. Under ultraviolet exposure condition the rate of degradation of pure TiO2 films shows an interesting linear correlation with pKa of the acids used. Moreover, the PEG addition into mineral sol–gel solution dramatically increases the rate of dye degradation under exposure. Nevertheless, no significant changes in the mechanical properties were observed after 100 h of UV and visible exposures
Different response to the same neural differentiation protocol of human embryonic stem cell lines HUES1 and HUES3
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