Screen printed Pb₃O₄ films and their application to photoresponsive and photoelectrochemical devices

A new and simple procedure for the deposition of lead (II, IV) oxide films by screen printing was developed. In contrast to conventional electrochemical methods, films can be also deposited on non-conductive substrates without any specific dimensional restriction, being the only requirement the thermal stability of the substrate in air up to 500 °C to allow for the calcination of the screen printing paste and sintering of the film. In this study, films were exploited for the preparation of both photoresponsive devices and photoelectrochemical cell photoanodes. In both cases, screen printing was performed on FTO (Fluorine-Tin Oxide glass) substrates. The photoresponsive devices were tested with I-V curves in dark and under simulated solar light with different irradiation levels. Responses were evaluated at different voltage biases and under light pulses of different durations. Photoelectrochemical cells were tested by current density⁻voltage (J-V) curves under air mass (AM) 1.5 G illumination, incident photon-to-current efficiency (IPCE) measurements, and electrochemical impedance spectroscopy

Graphene and MWCNT Printed Films: Preparation and RF Electrical Properties Study

Carbon materials are well known for being a versatile class of materials able to transmit an electrical signal when used as fillers in composites. Among numerous carbon fillers, carbon nanotubes and graphene have been extensively investigated for the last thirty years. This paper compares graphene and carbon nanotube electrical (i.e., resistive and reactive) properties in the microwave range up to 3 GHz. The transmission and reflection parameters of both the microstrip transmission lines and patch antennas loaded with 33 wt.% of graphene and multiwalled carbon nanotubes (MWCNTs) were analyzed. Interestingly, for an identical composite matrix composition, different scattering parameters stemmed from the different morphology of the films, the diverse interactions between the graphene nanoplatelets, MWCNTs, and polymeric binders in conjunction with the intrinsic electrical characteristics of the two carbon materials

Solid solutions of rare earth cations in mesoporous anatase beads and their performances in dye-sensitized solar cells

Solid solutions of the rare earth (RE) cations Pr3+, Nd3+, Sm3+, Gd3+, Er3+ and Yb3+ in anatase TiO2 have been synthesized as mesoporous beads in the concentration range 0.1-0.3% of metal atoms. The solid solutions were have been characterized by XRD, SEM, diffuse reflectance UV-Vis spectroscopy, BET and BJH surface analysis. All the solid solutions possess high specific surface areas, up to more than 100 m2/g. The amount of adsorbed dye in each photoanode has been determined spectrophotometrically. All the samples were tested as photoanodes in dye-sensitized solar cells (DSSCs) using N719 as dye and a nonvolatile, benzonitrile based electrolyte. All the cells were have been tested by conversion efficiency (J-V), quantum efficiency (IPCE), electrochemical impedance spectroscopy (EIS) and dark current measurements. While lighter RE cations (Pr3+, Nd3+) limit the performance of DSSCs compared to pure anatase mesoporous beads, cations from Sm3+ onwards enhance the performance of the devices. A maximum conversion efficiency of 8.7% for Er3+ at a concentration of 0.2% has been achieved. This is a remarkable efficiency value for a DSSC employing N719 dye without co-adsorbents and a nonvolatile electrolyte. For each RE cation the maximum performances are obtained for a concentration of 0.2% metal atoms. © 2015, Nature Publishing Group. All rights reserved

Morphological and RF Characterization of graphene composite films

Graphene is a monolayer of carbon atoms which exhibits remarkable electronic and mechanical properties. Graphene based nano-materials have gained a lot of interest for many applications. In this paper, a graphene inks with three concentrations (25 % in weight and 33 % in weight) were prepared and deposited, by screen printing. A detailed investigation of the surface morphology of the films using Scanning Electron Microscope (SEM) and Atomic Force Microscopy (AFM) revealed that the graphene films present a homogeneous dispersion of the filler with a comparatively lower surface roughness at higher concentrations, and negligible agglomerates. The films were then printed between copper electrodes on FR-4 substrate, commonly used in RF circuits, and the measured scattering parameters analysed. Finally, the reflection coefficient of a patch antenna, fabricated on FR-4 substrate with and without a stub loaded by a thin film were measured. The shift of the resonant frequency due to the presence of the graphene film (i.e. 430 MHz) shows attractive features of functionalized graphene films for chemical and bio-sensing applications

Design of a tri-axial surface micromachined MEMS vibrating gyroscope

Gyroscopes are one of the next killer applications for the MEMS (Micro-Electro-Mechanical-Systems) sensors industry. Many mature applications have already been developed and produced in limited volumes for the automotive, consumer, industrial, medical, and military markets. Plenty of high-volume applications, over 100 million per year, have been calling for low-cost gyroscopes. Bulk silicon is a promising candidate for low-cost gyroscopes due to its large scale availability and maturity of its manufacturing industry. Nevertheless, it is not suitable for a real monolithic IC integration and requires a dedicated packaging. New designs are supposed to eliminate the need for magnets and metal case package, and allow for a real monolithic MEMS-IC (Integrated Circuit) electronic system. In addition, a drastic cost reduction could be achieved by utilizing off-the-shelf plastic packaging with lead frames for the final assembly. The present paper puts forward the design of a novel tri-axial gyroscope based on rotating comb-drives acting as both capacitive sensors and actuators. The comb-drives are comprised of a single monolithic moving component (rotor) and fixed parts (stators). The former is made out of different concentrated masses connected by curved silicon beams in order to decouple the motion signals. The sensor was devised to be fabricated through the PolyMUMPs® process and it is intended for working in air in order to semplify the MEMS-IC monolithic integration

Equivalent Circuit Microwave Modeling of Graphene-loaded Thick Films Using S-parameters

Graphene, a one-atom thick layer of carbon atoms arranged to form a honeycomb lattice, exhibits intriguing mechanical, thermal and electrical properties, which makes it attractive for bio- and chemical sensors as well as flexible electronics applications. In this paper, graphene films with different amounts of graphene loading (weight fraction 12.5% and 25%) deposited by screen printing technique are characterized in the microwave frequency range. By fitting the measured scattering parameters of graphene-loaded microstrip lines with Advanced Design System (ADS) circuit simulations, a simple equivalent lumped circuit model of the film is obtained. The proposed equivalent lumped circuit model presented in this paper proves suitable as an initial step towards the full-wave electromagnetic modeling and analysis of graphene loaded microwave structures intended for sensing and tuning applications

Efficacy and safety of trabeculectomy vs nonpenetrating surgical procedures: a systematic review and meta-analysis

To date, only a few studies have directly compared nonpenetrating surgery (NPS) and trabeculectomy (TE). Therefore, there is no strong evidence as to which surgical technique leads to the best results in terms of ocular hypotensive effect and safety

Assessment of the Feasibility of an Extended Range Helicopter Operational Standard for Offshore Flights

The accident rate of rotorcraft has improved signi1cantly over the years but at a slow pace, and in any case the number of accidents per 2ight hours is one or two orders of magnitude higher than that of commercial aircraft, a consideration that could be reasonably related to the inherent higher risk associate with rotorcraft operations. This represent a strong evidence of the necessity to introduce airworthiness operation standards also in the rotorcraft community, as an effective mean to improve safety records, borrowing from the experience done in the commercial air transport community with the introduction of ETOPS. In this paper, a 1rst proposal of development of a safety standard for helicopter offshore operation is discussed together with the possible support to this development that could be given by the EU H2020 project NITROS

Double-blind placebo-controlled randomized clinical trial on the efficacy of Aerosal® in the treatment of sub-obstructive adenotonsillar hypertrophy and related diseases

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Wild bees in Southern Italy: impact of landscape management

ItGli impollinatori sono essenziali per il mantenimento degli ecosistemi, e i tre quarti delle principali colture alimentari del mondo necessitano dell'impollinazione animale per la produzione di frutti e semi. Negli ultimi decenni però stiamo assistendo ad un costante declino di questi importantissimi insetti in tutto il mondo, con un conseguente deficit nella produzione agricola. Se da un lato l'agricoltura è strettamente legata agli impollinatori, dall'altro è una delle cause del loro declino. Per questo motivo, in Italia, è nato il progetto "BeeNet", con lo scopo di valutare lo stato di salute degli ecosistemi agricoli italiani attraverso il monitoraggio delle api da miele e delle api selvatiche. In questo studio vengono presentati i dati del primo anno del progetto, 2021, sulle api selvatiche in due regioni meridionali (Campania e Puglia), comparando due ecosistemi agricoli diversi: uno intensivo e l'altro semi-naturale. Una volta al mese, da febbraio a ottobre, in entrambe le regioni ed entrambi gli ecosistemi, abbiamo campionato le api mediante un transetto (200 × 2 metri) percorso alla mattina e al pomeriggio. Inoltre, nelle stesse giornate abbiamo registrato tutte le specie botaniche mellifere presenti sul transetto. Le differenze riscontrate tra i due tipi di ecosistema indicano che l'agro-ecosistema intensivo ha in generale una biodiversità più bassa e una comunità di api più spostata verso specie generaliste. Questo risultato indica che l'uso di pratiche agricole più impattanti e l'omogeneità dell'ambiente influenzano fortemente, e negativamente, questi insetti e le piante spontanee di cui hanno bisogno per sopravvivere. Tuttavia, le differenze tra le ricchezze di specie e le abbondanze di specie tra i due tipi di ecosistema non sono risultate significative, e una possibile ragione di ciò potrebbe risiedere nell'irrigazione degli ecosistemi intensivi, che forse ha ridotto le differenze. È necessario quindi, in questi ambienti, attuare misure per la tutela degli impollinatori come richiesto dalla Comunità Europea, attraverso strategie mirate come ad esempio la nuova PAC 2023-2027.EnIn 2021, in two southern Italian regions (Campania and Puglia) we compared the biodiversity of both Apoidea and plants between intensive and semi-natural agro-ecosystems, aiming to evaluate the impacts of the agro-environment and agricultural practices on wild bees and spontaneous plant communities in southern Italy. Monthly, from February to October, we performed bee samplings (200 × 2 metres fixed transects) and botanical surveys in each site and region. We found no statistical differences between the two environments, probably because the two intensive agro-ecosystems were irrigated that year. However, the semi-natural agro-ecosystem was characterised by a higher biodiversity (bees and plants) and a higher rate of specialised bee species than the intensive agro-ecosystem, indicating that biodiversity benefits of agro-ecological practices and a more heterogeneous landscape