Tungsten and Titanium Oxide Thin Films Obtained by the Sol-Gel Process as Electrodes in Electrochromic Devices

In this work, WO3 and TiO2 thin films have been obtained by the sol-gel spin coating method. The as-deposited samples were annealed at different annealing temperatures in the range between 100°C and 500°C. Micro-Raman spectroscopy confirmed that WO3 thin films annealed at 100°C and 300°C are amorphous while the crystallization process occurred at 500°C as established by the typical Raman modes of γ-WO3. Amorphous thin films of TiO2 have been obtained using annealing at 100°C and 300°C. The crystalline phase of the anatase-TiO2 has been obtained after the thermal treatment conducted at 500°C. The electrochromic devices were characterized by cyclic voltammetry and UV–Vis–NIR spectroscopy and it has been shown that the best configurations of the electrochromic devices studied in this work can be obtained by using the WO3 thin films amorphous, which means annealed at 100°C and 300°C, and TiO2 thin films crystalline, that is annealed at 500°C. The higher coloration efficiency values in the visible region (λ = 550 nm) and in the near-infrared region (λ = 1020 nm) support the idea that such devices could be used in order to control the light flux but also heat flux. It means that such electrochromic devices can be usefully employed as smart windows promoting energy and economic savings

Study and micro-Raman characterization of pigments present on majolicas of historical and artistic interest from Gerace, Italy

AbstractIn this work, pigments of majolicas made between the sixteenth century and eighteenth century from Gerace have been characterized by micro-Raman spectroscopy. Majolica, known also as pottery, was originally used to identify all objects made from clay materials. In this work, ten samples were analyzed: two vases, six majolica fragments made in Gerace, one vase of uncertain origin (probably Gerace or Caltagirone) and one vase of Venetian origin. The Raman spectroscopic analysis allowed to identify most of the pigments present on the studied cultural heritage pottery above described. Pigments white, yellow, orange, red, blue, and green have been characterized and their attribution allowed to divide the artwork made in Gerace with those made wherever. Graphical Abstrac

Wide band gap materials as a new tuning strategy for dye doped cholesteric liquid crystals laser

A new tuning strategy for mirror-less liquid crystals laser is presented. A three layer cell is prepared with two cholesteric layers sandwiching a layer containing an isotropic mixture of a photoluminescent dye. One of the chiral layers contains a wide band gap material while the second layer consists of a series of small band gap materials. Through the combination of these two layers, a set of mirrors that can selectively reflect different wavelengths is obtained. A different laser wavelength is emitted from different regions of the cell under the pumping beam irradiation. (C) 2009 Optical Society of Americ

Electrically controllable multicolor cholesteric laser.

A new strategy to obtain multicolor lasing from cholesteric liquid crystals is presented. A four layer cell is prepared with three different cholesteric layers and a layer containing a photoluminescent dye. The three cholesteric mixtures are prepared so that their photonic band gaps are partially overlapped. Through this combination, two laser lines are obtained in the same spot under the pumping beam irradiation. Eventually, one of the laser lines can be switched off if an electric field is applied to the first or the last cholesteric layer

MICROCOGENERAZIONE SOLARE AD ALTA EFFICIENZA E PICCOLA SCALA ENERGETICA

Stopping the consumption of natural resources or at least sensibly slowing it down is a compulsory necessity felt at global level and this work, focused on a small solar microcogenerator in the range of 1 kW of electric power and up to 3 kW of thermal power, gives a contribution developing a system useful for the decentralised and diffuse production of electricity and heat with high conversion efficiencies at low power scale.  The presented solar microcogenerator makes use of an industrial Stirling engine of small size, with an electrical efficiency up to 32%, originally designed for domestic combined heat power applications in gas boilers. The heat acceptor of the Stirling head has been completely re-engineered for the solar application, together with an original solar dish concentrator moved by a suitable tracking system. At the considered energy power scale, this is a world first with an experimentation fully carried out at University of Calabria in a public-private collaboration framework

Paper like cholesteric interferential mirror

A new type of flexible cholesteric liquid crystal mirror is presented. The simple and effective method for the deposition of a cholesteric mixture on a paper substrate and the particular design of the device give a homogeneous alignment of the cholesteric texture providing mirrors with an intense and uniform light reflectance. A desired polarization state for the reflected light, linear or circular, can be easily obtained varying the thickness and optical anisotropy of the polymer cover film. By using non-azobenzene based photosensitive materials a permanent array of RGB mirrors with high reflectivity can be obtained on the same device. Paper like reflective mirrors are versatile and they can find applications in reflective displays, adaptive optics, UV detectors and dosimeters, information recording, medicine and IR converters

Flexible Physical Unclonable Functions based on non-deterministically distributed Dye-Doped Fibers and Droplets

The development of new anti-counterfeiting solutions is a constant challenge and involves several research fields. Much interest is devoted to systems that are impossible to clone, based on the Physical Unclonable Function (PUF) paradigm. In this work, new strategies based on electrospinning and electrospraying of dye-doped polymeric materials are presented for the manufacturing of flexible free-standing films that embed different PUF keys. Films can be used to fabricate anticounterfeiting labels having three encryption levels: i) a map of fluorescent polymer droplets, with non deterministic positions on a dense yarn of polymer nanofibers; ii) a characteristic fluorescence spectrum for each label; iii) a challenge-response pairs (CRPs) identification protocol based on the strong nature of the physical unclonable function. The intrinsic uniqueness introduced by the deposition techniques encodes enough complexity into the optical anti-counterfeiting tag to generate thousands of cryptographic keys. The simple and cheap fabrication process as well as the multilevel authentication makes such colored polymeric unclonable tags a practical solution in the secure protection of merchandise in our daily life

Inter-society consensus for the use of inhaled corticosteroids in infants, children and adolescents with airway diseases

Background: In 2019, a multidisciplinary panel of experts from eight Italian scientific paediatric societies developed a consensus document for the use of inhaled corticosteroids in the management and prevention of the most common paediatric airways disorders. The aim is to provide healthcare providers with a multidisciplinary document including indications useful in the clinical practice. The consensus document was intended to be addressed to paediatricians who work in the Paediatric Divisions, the Primary Care Services and the Emergency Departments, as well as to Residents or PhD students, paediatric nurses and specialists or consultants in paediatric pulmonology, allergy, infectious diseases, and ear, nose, and throat medicine. Methods: Clinical questions identifying Population, Intervention(s), Comparison and Outcome(s) were addressed by methodologists and a general agreement on the topics and the strength of the recommendations (according to the GRADE system) was obtained following the Delphi method. The literature selection included secondary sources such as evidence-based guidelines and systematic reviews and was integrated with primary studies subsequently published. Results: The expert panel provided a number of recommendations on the use of inhaled corticosteroids in preschool wheezing, bronchial asthma, allergic and non-allergic rhinitis, acute and chronic rhinosinusitis, adenoid hypertrophy, laryngitis and laryngospasm. Conclusions: We provided a multidisciplinary update on the current recommendations for the management and prevention of the most common paediatric airways disorders requiring inhaled corticosteroids, in order to share useful indications, identify gaps in knowledge and drive future research

Phase Diagram and Order Reconstruction Modeling for Nematics in Asymmetric π-Cells

Intense electric fields applied to an asymmetric π-cell containing a nematic liquid crystal subjected to strong mechanical stresses induce distortions that are relaxed through a fast-switching mechanism: the order reconstruction transition. Topologically different nematic textures are connected by such a mechanism that is spatially driven by the intensity of the applied electric fields and by the anchoring angles of the nematic molecules on the confining plates of the cell. Using the finite element method, we implemented the moving mesh partial differential equation numerical technique, and we simulated the nematic evolution inside the cell in the context of the Landau–de Gennes order tensor theory. The order dynamics have been well captured, putting in evidence the possible existence of a metastable biaxial state, and a phase diagram of the nematic texture has been built, therefore confirming the appropriateness of the used technique for the study of this type of problem

Deux phénomènes d'auto-adaptation dans les systèmes hors équilibre

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