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Impact of proton irradiation on photoluminescent properties of C-doped ZrO2 films prepared by ALD
Full text linkAmorphous C-doped zirconia thin films grown by ALD technique on fused silica substrates have high transmittance and significant photoluminescence (PL) capacity suitable for application as a transparent material to convert high energy into lower energy photons as well as an optical sensor of radiation. Due to carbon doping, zirconia films present three main PL transitions: Transition I and II at λem = 450 nm (λexc = 200 and 270 nm), related to sp3 and sp2 C–C bonds, and Transition III at λem = 450 nm (λexc = 300 nm) that can be assigned to C[dbnd]O bonds which introduce n levels in the π- π* gap. Protons with energy of 100 keV and two values of fluence (1∙1012 p+/cm2 and 5∙1014 p+/cm2) were used to modify the film properties. The changes induced by the radiation in the chemical composition of the films have been monitored as a function of irradiation dose using in-depth resolved XPS analysis which evidenced modification of C–Zr, Zr–O, C–H, C–C/C[dbnd]C and C[dbnd]O bonds. We demonstrate that C–Zr bonds formed in the film depth are cleaved by protonation in favor of Zr–O, C–H and C[dbnd]O bonds establishment. As a consequence, more defect levels are formed in the π- π* gap of carbon. Consequently, the emission due to Transitions III becomes more intense for high energy doses, getting intensity values close to Transitions I/II
Metabolomic profiling of blood and seminal plasma in the small-spotted catshark (Scyliorhinus canicula): A comparative study of aquarium and wild populations in the Valencia region
Full text linkIn chondrichthyans, despite males in ex situ conservation programs exhibiting good sperm quality, offspring production is confined to specific species. This study hypothesizes that the aquarium's environmental footprint may contribute to this loss of reproductive capacity. Consequently, the research initially focused on comparing the blood metabolomic profiles of the Small-Spotted Catshark (Scyliorhinus canicula) in both an aquarium environment at Oceanogràfic of Valencia and in wild populations along the Valencia Region coast (Spain). Furthermore, the study compared the blood metabolomic profiles with those of seminal plasma. This comparison aimed to identify potential variations in seminal plasma composition and its relationship with in vitro seminal characteristics. Samples were collected from S. canicula present in the aquarium (n = 7) and wild captured individuals (n = 12). Despite conventional semen quality assessments showing no significant disparities in semen volume and sperm concentration, considerable differences were observed in sperm motility and viability rates. Specifically, aquarium specimens showed slightly reduced metrics. The untargeted metabolic study in blood revealed significant differences between aquarium and wild individuals, with 158 semi-polar and 233 non-polar differential metabolites. A parallel analysis of seminal plasma similarly revealed substantial differences, with 2 semi-polar and 74 non-polar differential metabolites. Additionally, the analysis showed 104 semi-polar and 188 non-polar metabolites shared between the blood and seminal plasma of both animal groups. A further targeted analysis of 28 metabolites in blood identified significantly lower concentrations of phenylalanine, tyrosine, lysine, taurine, arginine, N-acetyl-L-glutamate, and creatinine in aquarium sharks. In seminal plasma samples, aquarium animals exhibited elevated levels of 7-Dehydrodesmosterol but reduced levels of phenylalanine, pantothenic acid (Vit B5), and spermine. In conclusion, these findings highlight alterations in both the blood and seminal plasma metabolomic profiles between aquarium-housed and wild animals, demonstrating the impact of the aquarium's environmental footprint, which could partly explain the reduced reproductive success of sharks in captivity
Overview of recent advancements in IFMIF-DONES neutronics activities
Full text linkRecent advancements in the neutronics activities of the IFMIF-DONES project, developed within the EUROfusion framework, are presented. These include updates to radiation dose maps during commissioning and normal operation of the accelerator systems; material irradiation analyses and shielding optimization of the test systems; activation inventories of 7Be, 3H, and activated corrosion products in the Li systems; shutdown dose analyses of transportation and storage of radioactive waste, cooling water and atmosphere gas activations, skyshine to the public, etc. The development of simulation tools, nuclear data evaluation, and nuclear experiments for the specific needs of DONES neutronics are highlighted, as well as the nuclear analysis handbook and database. Several challenges for future development are also discussed to ensure the provision of high-quality nuclear analyses
Skeletal mineralogy of marine calcifying organisms shaped by seawater temperature and evolutionary history—A case study of cheilostome bryozoans
Full text linkAim: Quantify the contribution of environmental factors (water temperature, salinity and depth) and evolutionary history to varied skeletal mineralogy in calcifying marine organisms. Location: Global Ocean. Time period: Present. Major taxa studied: Order: Cheilostomatida; Phylum: Bryozoa. Methods: We employed X-ray diffraction (XRD) to analyse the skeletal mineral composition of 872 individual colonies, representing 437 bryozoan species, in terms of calcite/aragonite ratios. We integrated these data with equivalent published data, thus reaching 981 species, and applied linear models (LMs), generalized linear models (GLMs) and phylogenetic generalized least squares models (PGLSs) to investigate the influences of temperature, salinity, depth and phylogenetic history on the mineralogy of nearly 1000 cheilostome bryozoan species. Results: Cheilostome bryozoans vary considerably in their skeletal mineral composition: in our dataset 65% of the species possess purely calcite skeletons, 15% exclusively employ aragonite and 20% exhibit mixed (i.e. calcite and aragonite) mineralogies. Temperature is the predominant measured environmental factor influencing bryozoan skeletal mineralogy, accounting for 20% of its variability across species, when phylogenetic relatedness is unaccounted for. Bryozoans in lower latitudes, characterized by higher seawater temperatures, have higher aragonite concentrations. By accounting for phylogenetic structure using a subset of 87 species for which we have topological information, 40% of the observed mineralogical variability could be attributed to present-day temperature. In contrast, depth and salinity played minor roles, explaining less than 1% of the mineralogical variation each. Main conclusions: This study emphasizes the influence of evolutionary history on the mineralogical variability of calcifying organisms, even when it can be shown that a single environmental factor (temperature) explains a substantial amount of this variability. When confronted with changing temperature, calcifiers such as bryozoans are likely to respond in diverse ways, depending on the species, given their phylogenetic relatedness and the external conditions they meet
LIBS diagnostics of Be-based samples with different gas impurities
Full text linkControlling plasma fuel retained in the plasma facing components of the first wall of a fusion reactor is one of the most important challenges influencing safe operation of the International Thermonuclear Experimental Reactor in the first place. This issue is proposed to be addressed by the laser-induced breakdown spectroscopy (LIBS) diagnostics, which is particularly powerful in studying the near-surface deposits and analyzing their composition. The main goal of the present study is determining the depth profiles of different elements in beryllium-based materials and the possible co-deposited layers that are formed on the walls of the Joint European Torus (JET) fusion device. Depth profiles estimated by LIBS are compared with those measured by secondary ion mass spectrometry, furthermore, the differences are discussed. In particular, the evolution of spectral lines of Be, as well as the main gaseous elements, such as Ne, N, O, and D, incorporated into the samples were extracted at different depths in the layers. LIBS diagnostics allowed making a fairly accurate analysis of the detected spectral lines of the elements on the samples. The effect of variations of the ablation rate and uncertainty that it introduces in LIBS measurements was also discussed. This investigation will have a significant impact on the development of pre-processing algorithms for machine learning models in terms of adaptation models operating on synthetic data for processing experimental spectra and is important from a point of view of LIBS tests being under preparation at JET
Pre-pilot scale study of hydrogen production from biomass syngas via water-gas shift in Pd–Ag catalytic membrane reactor and dedicated hydrogen permeation unit
No full textThe water-gas shift reaction (WGS) was evaluated in two Pd–Ag membrane reactors operating in parallel and capable of processing 0.25 Nm3·h−1 of syngas. Various configurations, syngas compositions, and steam flow rates were explored within the temperature range of 300–350 °C and pressure range of 4–8bar. The performances were evaluated in a coupled configuration, consisting of a permeator and a membrane reactor operating in series, and single configuration of membrane reactor. Two syngas mixtures were fed and treated under different combinations of temperature, pressure, and steam/CO ratio. The syngas composition used was, in one case that typically produced by updraft gasifiers operated with air and having a content of H2 19.1 vol% and, in the second case, having content of 36.8 vol%, typically achievable by oxy-steam gasification. Carbon monoxide conversion, hydrogen permeation, and hydrogen permeability of membranes were determined. The use of these membranes effectively enhances the WGS reaction, overcoming the performances of a Gibbs reactor, and produces streams of ultrapure hydrogen. Competitive strong adsorption of CO was suggested from the permeability analysis and comparison with existing literature
Large Eddy Simulation of Hydrogen/Air MILD combustion in a cyclonic burner
Full text linkIn this work Large Eddy Simulation (LES) of a Hydrogen/Air cyclonic burner operating in the MILD combustion regime at 1 atm is performed. The cyclonic flow configuration may represent a proper way to enhance the mixing process in a very short time while allowing for residence times long enough to achieve complete oxidation of diluted and preheated mixtures. Accurate molecular transport properties and a reduced chemical mechanism for hydrogen-air combustion, consisting of 18 transported species and 244 elementary reactions are considered. Results show that at the center of the combustor, where MILD combustion occurs, temperature exhibits a statistically steady trend (a mean of 1450 K) with peak values lower than 1700 K. This implies that the Zeldovich mechanism for thermal NO formation is negligible, so NO levels are low and statistically steady with a maximum peak of 20 ppm. These values are lower than those observed in standard combustion, confirming the ability of MILD to reduce NOx pollutants also with hydrogen as fuel. Finally, the simulations outcomes are in very good agreement with the experimental results, in particular radiative heat transfer must be taken into account to better capture the preheating of the reactants and consequently fit the experimental temperature profiles in the combustion chamber
RFX-mod2 as a flexible device for reversed-field-pinch and low-field tokamak research
Full text linkThe RFX-mod2 installation is planned to be completed by 2024 and the start of operations is expected in 2025. The high flexibility of the machine (already tested in the previous RFX-mod experiment) allows operation in Reversed Field Pinch and tokamak configuration as well as ultra-low q pulses. In this work we present predictive analysis on transport, performances and plasma control in RFX-mod2 in view of the first experimental campaigns
Multi-Technique Approach for the Sustainable Characterisation and the Digital Documentation of Painted Surfaces in the Hypogeum Environment of the Priscilla Catacombs in Rome
Full text linkThe purpose of this paper is to identify an efficient, sustainable, and “green” approach to address the challenges of the preservation of hypogeum heritage, focusing on the problem of moisture, a recurring cause of degradation in porous materials, especially in catacombs. Conventional and novel technologies have been used to address this issue with a completely non-destructive approach. The article provides a multidisciplinary investigation making use of advanced technologies and analysis to quantify the extent and distribution of water infiltration in masonry before damage starts to be visible or irreversibly causes damage. Four different technologies, namely Portable Nuclear Magnetic Resonance (NMR), Audio Frequency–Acoustic Imaging (AF–AI), Laser-Induced Fluorescence (LIF), Infrared Thermography (IRT), and 3D Laser Scanning (RGB-ITR), were applied in the Priscilla catacombs in Rome (Italy). These imaging techniques allow the characterisation of the deterioration of painted surfaces within the delicate environment of the Greek chapel in the Priscilla catacombs. The resulting high-detailed 3D coloured model allowed for easily referencing the data collected by the other techniques aimed also at the study of the potential presence of salt efflorescence and/or microorganisms. The results supply an efficient and sustainable tool aimed at cultural heritage conservation but also at the creation of digital documentation obtained with green methodologies for a wider sharing, ensuring its preservation for future generations
The overall sustainability index (OSI): A suitable way to measure the sustainability of electrical industry in Italy
No full textThe objective of this research is to develop a comprehensive and effective quantita-tive method to measure the overall sustainability performance of electric companiesin Italy. Due to the vast diversity of the sustainability issues, many methods havebeen developed to measure the sustainability performance of companies, but withresults that are, in our opinion, not fully satisfactory, either because they are difficultto apply or because they only cover some of the sustainability aspects. In an attemptto overcome these shortcomings, we have applied a methodology to meet therequirements of our research, on the basis of its high versatility (https://lab24.ilsole24ore.com/qualita-della-vita/). The analysis was carried out on the 12 largestItalian electricity companies, by calculating the overall sustainability index (OSI) forthe years 2020 and 2021, taking into account 56 different indicators, chosen fromthose made available by the Global Reporting Initiative (GRI) for corporate sustain-ability reporting. For a more comprehensive evaluation of the sustainability perfor-mance of the electricity companies, selected indicators were chosen from all thethree pillars of sustainability (economic, environmental, social). The OSI results of thisresearch have allowed to highlight the critical points of the corporate reporting sys-tems on sustainability providing valuable indications on the targets achieved andachievable in view of the European Commission's Green Deal 2050. This work alsohighlighted the strengths and weaknesses of the metho