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Evidence of Gd substitution for Y in YBCO films with Gd excess
Get PDFGd-YBa2Cu3O7-δ (Gd-YBCO) thin films with 10 mol% and 20 mol% excess-Gd concentration with respect to Y were investigated at the Gd L3 and Y K core absorption edges by EXAFS spectroscopy with the aim of determining the local structure of the Gd dopant. To this purpose, EXAFS data were collected also on GdBa2Cu3O7-δ (GdBCO) and pristine YBCO films and on Gd2O3 and Y2O3 model compounds for comparison with the YBCO films with Gd excess. The EXAFS analysis was based on Y and Gd oxides as well as on a cluster obtained by Density Functional Theory (DFT) where Gd atoms were inserted substitutional to Y atoms. The EXAFS data clearly reveal the incorporation of Gd in the lattice as substitute of Y and no evidence of segregated Gd oxide was found within the film matrix
K*(892)± resonance production in Pb-Pb collisions at sNN =5.02 TeV
No full textThe production of K∗(892)± meson resonance is measured at midrapidity (|y|<0.5) in Pb-Pb collisions at sNN=5.02 TeV using the ALICE detector at the CERN Large Hadron Collider. The resonance is reconstructed via its hadronic decay channel K∗(892)±→KS0π±. The transverse momentum distributions are obtained for various centrality intervals in the pT range of 0.4-16 GeV/c. Measurements of integrated yields, mean transverse momenta, and particle yield ratios are reported and found to be consistent with previous ALICE measurements for K∗(892)0 within uncertainties. The pT-integrated yield ratio 2K∗(892)±/(K++K-) in central Pb-Pb collisions shows a significant suppression at a level of 9.3σ relative to pp collisions. Thermal model calculations result in an overprediction of the particle yield ratio. Although both hadron resonance gas in partial chemical equilibrium (HRG-PCE) and music + smash simulations consider the hadronic phase, only HRG-PCE accurately represents the measurements, whereas music + smash simulations tend to overpredict the particle yield ratio. These observations, along with the kinetic freeze-out temperatures extracted from the yields measured for light-flavored hadrons using the HRG-PCE model, indicate a finite hadronic phase lifetime, which decreases with increasing collision centrality percentile. The pT-differential yield ratios 2K∗(892)±/(K++K-) and 2K∗(892)±/(π++π-) are presented and compared with measurements in pp collisions at s=5.02 TeV. Both particle ratios are found to be suppressed by up to a factor of five at pT<2.0 GeV/c in central Pb-Pb collisions and are qualitatively consistent with expectations for rescattering effects in the hadronic phase. The nuclear modification factor (RAA) shows a smooth evolution with centrality and is found to be below unity at pT>8 GeV/c, consistent with measurements for other light-flavored hadrons. The smallest values are observed in most central collisions, indicating larger energy loss of partons traversing the dense medium
Gamma irradiation for Cultural Heritage conservation: Comparison of the side effects on new and old paper
Get PDFIonizing radiations, commonly applied as diagnostic tools in Cultural Heritage (CH) field, are also proving effective for eliminating biodeteriogens (insects, fungi, bacteria and molds) responsible for the degradation of CH artifacts and often harmful for restorers, archivists and librarians. The use of ionizing radiations, such as gamma rays, for CH treatments is spreading in many countries. However, some CH operators remain resistant due to insufficient knowledge about the potential physico-chemical modifications (secondary effects) induced by radiation. This work aims to investigate and compare the effects of irradiation parameters (such as absorbed dose and dose rate) on old paper samples and new pure-cellulose paper, chosen as a reference model material. Absorbed doses up to 8 kGy have been used, as these values are commonly agreed upon for the preservation treatment of CH artifacts and are generally effective for biodeteriogens removal. Optimizing irradiation conditions helps to minimize secondary effects (such as oxidation, depolymerization or color changes), thereby increasing the reliability of the process and boosting confidence among CH operators. The secondary effects were analyzed using various physico-chemical characterizations (Fourier Transform Infrared spectroscopy, Raman microscopy, viscosimetric and colorimetric analysis) on old and new paper samples. The results indicate varying behaviors, correlated with paper composition, sample age and irradiation parameters, towards gamma radiation. This groundbreaking study not only confirms the efficacy of gamma irradiation treatments but also provides essential data that will aid in the development of optimized best practice protocols and guidelines for non-destructive and minimally destructive methods applied to real case studies and treatments
Unveiling new perspectives of hypergeometric functions using umbral techniques
Get PDFThe umbral restyling of hypergeometric functions is shown to be a useful and efficient approach in simplifying the associated computational technicalities. In this article, the authors provide a general introduction to the umbral version of Gauss hypergeometric functions and extend the formalism to certain generalized forms of these functions. It is shown that suggested approach is particularly efficient for evaluating integrals involving hypergeometric functions and their combination with other special functions
On the dose-response association of fine and ultrafine particles in an urban atmosphere: toxicological outcomes on bronchial cells at realistic doses of exposure at the Air Liquid Interface
Get PDFAir pollution and particulate matter (PM) are the leading environmental cause of death worldwide. Exposure limits have lowered to increase the protection of human health; accordingly, it becomes increasingly important to understand the toxicological mechanisms on cellular models at low airborne PM concentrations which are relevant for actual human exposure. The use of air liquid interface (ALI) models, which mimic the interaction between airborne pollutants and lung epithelia, is also gaining importance in inhalation toxicological studies. This study reports the effects of ALI direct exposure of bronchial epithelial cells BEAS-2B to ambient PM1 (i.e. particles with aerodynamic diameter lower than 1 μm). Gene expression (HMOX, Cxcl-8, ATM, Gadd45-a and NQO1), interleukin (IL)-8 release, and DNA damage (Comet assay) were evaluated after 24 h of exposure. We report the dose-response curves of the selected toxicological outcomes, together with the concentration-response association and we show that the two curves differ for specific responses highlighting that concentration-response association may be not relevant for understanding toxicological outcomes. Noteworthy, we show that pro-oxidant effects may be driven by the deposition of freshly emitted particles, regardless of the airborne PM1 mass concentration. Furthermore, we show that reference airborne PM1 metrics, namely airborne mass concentration, may not always reflect the toxicological process triggered by the aerosol. These findings underscore the importance of considering different aerosol metrics to assess the toxicological potency of fine and ultrafine particles. To better protect human health additional metrics should be defined, than account for the properties of the entire aerosol mixture including specific as particle size (i.e. particles with aerodynamic diameter lower than 20 nm), the relevant aerosol sources (e.g., traffic combustion, secondary organic aerosol ...) as well as their atmospheric processing (freshly emitted vs aged ones)
Genome Insights into Beneficial Microbial Strains Composing SIMBA Microbial Consortia Applied as Biofertilizers for Maize, Wheat and Tomato
Get PDFFor the safe use of microbiome-based solutions in agriculture, the genome sequencing of strains composing the inoculum is mandatory to avoid the spread of virulence and multidrug resistance genes carried by them through horizontal gene transfer to other bacteria in the environment. Moreover, the annotated genomes can enable the design of specific primers to trace the inoculum into the soil and provide insights into the molecular and genetic mechanisms of plant growth promotion and biocontrol activity. In the present work, the genome sequences of some members of beneficial microbial consortia that have previously been tested in greenhouse and field trials as promising biofertilizers for maize, tomato and wheat crops have been determined. Strains belong to well-known plant-growth-promoting bacterial genera such as Bacillus, Burkholderia, Pseudomonas and Rahnella. The genome size of strains ranged from 4.5 to 7.5 Mbp, carrying many genes spanning from 4402 to 6697, and a GC content of 0.04% to 3.3%. The annotation of the genomes revealed the presence of genes that are implicated in functions related to antagonism, pathogenesis and other secondary metabolites possibly involved in plant growth promotion and gene clusters for protection against oxidative damage, confirming the plant-growth-promoting (PGP) activity of selected strains. All the target genomes were found to possess at least 3000 different PGP traits, belonging to the categories of nitrogen acquisition, colonization for plant-derived substrate usage, quorum sensing response for biofilm formation and, to a lesser extent, bacterial fitness and root colonization. No genes putatively involved in pathogenesis were identified. Overall, our study suggests the safe application of selected strains as “plant probiotics” for sustainable agriculture
Benchmark exercise on ELSMOR passive heat removal system
No full textThe EU-funded ELSMOR (Towards European Licencing of Small Modular Reactors) project seeks to design methods and tools for stakeholders to assess and verify Light Water SMRs’ safety when installed across Europe. Within the project, an experimental facility has been built at SIET (Piacenza, Italy) to test a passive heat removal system. The passive system is based on natural circulation, with a plate-type Compact Steam Generator (CSG) as heat source and an in-pool condenser as heat sink. An experimental campaign has been conducted to investigate the effect of different parameters on the passive system behavior (e.g. secondary side filling ratio, primary system temperature, pool level, presence of non-condensable gases, etc.). Among the various tests, ELSMOR test 00099_C has been selected to perform a code benchmark and ten parameters were selected for the code comparison. The chosen test explores the effect of the secondary side filling ratio from 60.16% to 24.96%. In the benchmark, the codes from the European reference chains have been applied, Apros by VTT, AC2 by GRS and CATHARE by CEA, and they have been compared with the results obtained with RELAP5 by ENEA and TRACE by PSI. In general, all the codes were able to predict the experimental data both from a qualitative and quantitative point of view. The main discrepancies have been observed in some results for the prediction of the secondary side pressure, secondary side CSG inlet temperature and secondary side flow rate
Helium plasma operations on ASDEX Upgrade and JET in support of the non-nuclear phases of ITER
Get PDFFor its initial operational phase, ITER has until recently considered using non-nuclear hydrogen (H) or helium (He) plasmas to keep nuclear activation at low levels. To this end, the Tokamak Exploitation Task Force of the EUROfusion Consortium carried out dedicated experimental campaigns in He on the ASDEX Upgrade (AUG) and JET tokamaks in 2022, with particular emphasis put on the ELMy H-mode operation and plasma-wall interaction processes as well as comparison to H or deuterium (D) plasmas. Both in pure He and mixed He + H plasmas, H-mode operation could be reached but more effort was needed to obtain a stable plasma scenario than in H or D. Even if the power threshold for the LH transition was lower in He, entering the type-I ELMy regime appeared to require equally much or even more heating power than in H. Suppression of ELMs by resonant magnetic perturbations was studied on AUG but was only possible in plasmas with a He content below 19%; the reason for this unexpected behaviour remains still unclear and various theoretical approaches are being pursued to properly understand the physics behind ELM suppression. The erosion rates of tungsten (W) plasma-facing components were an order of magnitude larger than what has been reported in hydrogenic plasmas, which can be attributed to the prominent role of He2+ ions in the plasma. For the first time, the formation of nanoscale structures (W fuzz) was unambiguously demonstrated in H-mode He plasmas on AUG. However, no direct evidence of fuzz creation on JET was obtained despite the main conditions for its occurrence being met. The reason could be a delicate balance between W erosion by ELMs, competition between the growth and annealing of the fuzz, and coverage of the surface with co-deposits
Lithium Toxicity in Lepidium sativum L. Seedlings: Exploring Li Accumulation’s Impact on Germination, Root Growth, and DNA Integrity
Get PDFThe predicted increase in demand for minor metals for modern technologies raises major concerns regarding potential environmental concentration increases. Among the minor metals, lithium (Li) is particularly noteworthy due to growing demand for battery production. Concerns have been raised about the impact on biota of increasing Li concentrations in the environment. To expand the knowledge of the effects of Li on plants, garden cress (Lepidium sativum L.), a model plant for ecotoxicity assay, was tested in a 72 h test in Petri plates. The results showed a stimulation effect of Li at the lowest concentration (Li chloride 10 mg L−1) on seed germination and primary root elongation. Conversely, higher Li concentrations (50 and 150 mg L−1) caused a progressive impairment in both parameters. A genotoxic effect of Li on root cells, evaluated through the alkaline comet assay, was observed at each concentration tested, particularly at 150 mg L−1 Li chloride. Elemental analysis showed that Li accumulated in the seedlings in a dose–concentration relationship, confirming its ability to be readily absorbed and accumulated in plants. Given the likely increase in Li levels in the environment, further research is required to clarify the toxicity mechanisms induced by Li on growth and nucleic acids
A Survey on Anomalies and Faults That May Impact the Reliability of Renewable-Based Power Systems
Get PDFThe decarbonization of the electricity grid is one of the actions that can help reduce fossil fuel emissions, and thus their impact on global warming in the future. This decarbonization will be achieved mainly through the integration and widespread diffusion of renewable power sources. This is also going to be supported by the shift from the paradigm of production–transmission–distribution, where electricity production oversees large-size power plants, to renewable-based distributed/diffused production, where electricity is generated very close or even by the same (group of) user(s) (or prosumers in the latter case). The number of mid-/small-size installations based on renewable energy technologies will therefore increase substantially, and the related renewable generation will be dominant against that from large-size power plants. Unfortunately, this will very likely reduce the reliability of the grid, unless appropriate countermeasures are taken/implemented, hopefully at the same time that the paradigm shift is being achieved. To this aim, it is important to identify the anomalies and main fault causes that might possibly affect some of the central renewable (wind, PV, hydrogen) and ancillary technologies that will be used to establish future renewable-based power systems. Accordingly, this paper presents a literature survey, also extending the focus to related datasets that can be used for deeper investigation. It is highlighted that the gaps mainly refer to a lack of a common taxonomy that prevents the establishment of structured knowledge in the scope of renewable-based power systems, a lack of contributions to anomalies/faults specific to wind turbines, and a lack of datasets related to electrolyzers, fuel cells, DC/x conversion, and monitoring and communication systems. Further, in the case of monitoring and communication systems, the scientific literature is both very dated, therefore not considering possible new aspects that would be currently worthy of investigation, and not oriented toward the particular domain addressed, thus considering peculiar aspects that are left out