1,721,173 research outputs found
MURANO PIXEL. An experimental and shared research.
No full textThe paper describes the motivation, approach and working methodology of a research project financed with POR FSE funds by the Veneto Region. The research involved two universities (Università Iuav di Venezia and Università Ca’ Foscari Venezia), three glassworks in Murano, two network partners (Anteferma Edizioni and WASP) dedicated to innovation and the dissemination of innovation, and three young researchers. A network of professional figures, production realities and interlocutors developed around the figures institutionally involved in the project. These collaborations arose from the desire to share knowledge, production skills and experimentation. Moreover, the research was not limited to Murano but opened up this territory to international debate. This paper proposes the Venice Lagoon as a case study to develop research dedicated to the recycling of materials towards an increasingly comprehensive and complex approach. This is a challenge. The short circuit between the vitality of artisan work and research activity must be triggered
Cu-doped photovoltaic glasses by ion exchange for sunlight down-shifting
No full textIon exchange process is a widely studied synthesis technique for the controlled modification of silicate
glass composition and properties, being moreover an easy and cheap approach. Silicate glasses containing
copper are known to exhibit a broad luminescent band peaked around 500 nm, ascribed to 3d10-3d94s1 electronic transition of Cu+ ions; this band turns out to be much promising for the realization of
down-shifting systems, being excited in the UV and neareUV region. Luminescent Cuedoped silicate
glass sheets suitable as downeshifters to be used for covering solar cells have been prepared by thermal
ion exchange. Synthesis of the Cuedoped glasses has been done by dipping pure silicate sheets
(commercially used as cover of photovoltaic panels) into a fused copper salt mixture at temperature of
400 °C, for duration between a few minutes and some hours; two different types of copper chloride salt
mixtures were explored, with the aim at obtaining luminescent glasses able to improve the Si cell yield.
Absorption and luminescence glass features were collected and compared. The performance of the
different samples was tested by a solar simulator, measuring the output power of a Si solar cell covered
with the Cuedoped glass slides
Multi-edge X-ray absorption spectroscopy study of road dust samples from a traffic area of Venice using stoichiometric and environmental references
No full textThe appropriate selection of representative pure compounds to be used as reference is a crucial step for successful analysis of X-ray absorption near edge spectroscopy (XANES) data, and it is often not a trivial task. This is particularly true when complex environmental matrices are investigated, being their elemental speciation a priori unknown. In this paper, an investigation on the speciation of Cu, Zn, and Sb based on the use of conventional (stoichiometric compounds) and non-conventional (environmental samples or relevant certified materials) references is explored. This method can be useful in when the effectiveness of XANES analysis is limited because of the difficulty in obtaining a set of references sufficiently representative of the investigated samples. Road dust samples collected along the bridge connecting Venice to the mainland were used to show the potentialities and the limits of this approach
Modelling the ion exchange process in glass: Phenomenological approaches and perspectives
No full textA great deal of work has been devoted in the last decades to the study of the ion exchange process modelling, in order to tailor the physical properties of the modified layers, e.g. refractive index or stress profiles. The first models were based on simple ionic diffusion equations, while in the last years it became clear that the glass undergoes local restructuring during the ion exchange even at temperatures lower than the glass transition one. The aim of this work is to review the approaches that lead to the introduction of self-diffusion coefficients depending on the concentration of the migrating cations, and to outline a physical approach in selecting a phenomenological expression for the coefficients. In particular, this approach refers to models developed for describing the ionic diffusion in mixed-alkali glasses
Formation of alloy nanoparticles by laser ablation of Au/Fe multilayer films in liquid environment
No full textLaser ablation in liquids (LAL) emerged as a powerful technique for the synthesis of multielement nanoparticles (NPs) such as metal alloys with thermodynamically forbidden composition. Consequently, there is a great interest in expanding the current knowledge about NPs formation during LAL, in order to improve the control on product structure and to extend the range of compositions accessible by this technique. Here we performed a systematic investigation on alloy NPs formation by nanosecond LAL of Au/Fe/glass multilayers with different thickness and order of deposition. The experiments were carried out in ethanol and water, which have, respectively, favourable and unfavourable effects on alloy formation. Results were analyzed with optical absorption spectroscopy, transmission electron microscopy and Mie theory for simple and core-shell spheres. Since alloy NPs were obtained in all cases, our findings provide the evidence that the two metals are mixed during particles formation. Besides, our results suggest that the probability of interaction between ablated matter and solution species is higher for the topmost layer of the target, i.e. the one closer to the solid/liquid interface. This provides useful insight for the synthesis of nanoalloys with new compositions, that are of interest in several fields, from catalysis to photonics and nanomedicine
Photo-Thermo-Refractive Glasses Doped with Silver Molecular Clusters as Luminescence Downshifting Material for Photovoltaic Applications
No full textSilver nanostructures, including molecular clusters and plasmonic nanoparticles, attract much attention due to their unique optical properties and potential applications in various fields. Glasses doped with silver molecular clusters are known to possess bright luminescence under UV excitation, which opens up prospects of using the glasses as solar spectral converters to overcome poor spectral response for most of photovoltaic cells in the short-wavelength region. In this study, silver molecular clusters are formed in photo-thermo-refractive glass matrix both by UV irradiation and by Na+↔Ag+ion exchange and optically characterized. Photo-thermo-refractive glasses doped with silver molecular clusters, independently on silver introduction method, are shown to demonstrate broad absorption in the UV, intense white emission under excitation at 360 nm, and high photoluminescence quantum yield that meet requirements for luminescence downshifting materials. Despite this, only photo-thermo-refractive glass with silver molecular clusters uniformly distributed in the glass volume enhances the output power of a silicon photovoltaic cell, thus showing the potential for future application of photo-thermo-refractive glasses in photovoltaics, particularly in case of further experiments
A review of glass corrosion: the unique contribution of studying ancient glass to validate glass alteration models
Full text linkGlass has been used in widespread applications within several sectors since ancient times and it has been systematically studied under different perspectives. However, its thermodynamic properties and the variety of its compositions, several aspects related to its durability and its alteration mechanisms remain still open to debate. This literature review presents an overview of the most relevant studies on glass corrosion and the interaction between glass and the environment. The review aims to achieve two objectives. On one hand, it aims to highlight how far research on glass corrosion has come by studying model systems created in the laboratory to simulate different alteration conditions and glass compositions. On the other, it seeks to point out what are the critical aspects that still need to be investigated and how the study of ancient, altered glass can add to the results obtained in laboratory models. The review intends also to demonstrate how advanced analytical techniques commonly used to study modern and technical glass can be applied to investigate corrosion marks on ancient samples
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