128 research outputs found

    Na-seawater battery technology integration with renewable energies: The case study of Sardinia Island

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    Europe has committed to net zero carbon dioxide emissions by 2050 to boost the clean energy transition. Renewable electricity will be the key energy medium for decarbonization and a huge increase in renewable energy sources (RES) exploitation is expected. Due to RES stochastic character, an extensive energy storage integration in the energy system is needed to avoid the mismatch between generation and demand profiles. Reactive metals are promising energy carriers and storage media characterized by high volumetric energy densities and circularity, due to ease of storage and transportation, material availability and low cost. Among them, sodium is a largely available element since it can be extracted from seawater and exploited through the innovative sodium-seawater battery (SWB). Sodium cations are transferred from SWB’s open cathode to the anode side during charging. Upon discharge, Na metal is oxidized to Na+^+ ions, which are discarded in seawater. This study assesses the impact of SWB technology focusing on Sardinia Island as a case study. For short-term application, SWB integration to wave energy converters allows a potential reduction of greater than 85% of generated power fluctuations, largely improving the quality of power injected into the grid. Regarding the long-term scenario, SWBs implementation in the energy system allows coverage of the Sardinia annual energy demand thanks to the integration of ∼340,000 cubic meter of Na metal, corresponding to a 12-m height Na reservoir under 4 soccer fields. SWB application to Sardinia also produces CO2_2 sequestration while covering ∼29% of desalinated water requirements for the Sardinian population

    A Dedicated Tool for Presurgical Mapping of Brain Tumors and Mixed-Reality Navigation During Neurosurgery

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    Brain tumor surgery requires a delicate tradeoff between complete removal of neoplastic tissue while minimizing loss of brain function. Functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) have emerged as valuable tools for non-invasive assessment of human brain function and are now used to determine brain regions that should be spared to prevent functional impairment after surgery. However, image analysis requires different software packages, mainly developed for research purposes and often difficult to use in a clinical setting, preventing large-scale diffusion of presurgical mapping. We developed a specialized software able to implement an automatic analysis of multimodal MRI presurgical mapping in a single application and to transfer the results to the neuronavigator. Moreover, the imaging results are integrated in a commercially available wearable device using an optimized mixed-reality approach, automatically anchoring 3-dimensional holograms obtained from MRI with the physical head of the patient. This will allow the surgeon to virtually explore deeper tissue layers highlighting critical brain structures that need to be preserved, while retaining the natural oculo-manual coordination. The enhanced ergonomics of this procedure will significantly improve accuracy and safety of the surgery, with large expected benefits for health care systems and related industrial investors

    Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

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    A measurement of the cosmic-ray spectrum for energies exceeding 4×10184{\times}10^{18} eV is presented, which is based on the analysis of showers with zenith angles greater than 6060^{\circ} detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above 5.3×10185.3{\times}10^{18} eV, the "ankle", the flux can be described by a power law EγE^{-\gamma} with index γ=2.70±0.02(stat)±0.1(sys)\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)} followed by a smooth suppression region. For the energy (EsE_\text{s}) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find Es=(5.12±0.25(stat)1.2+1.0(sys))×1019E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19} eV.Comment: Replaced with published version. Added journal reference and DO

    Communication and visiting policies in Italian intensive care units during the first COVID-19 pandemic wave and lockdown: a nationwide survey

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    Background: During the first coronavirus disease 2019 (COVID-19) pandemic wave, an unprecedented number of patients with respiratory failure due to a new, highly contagious virus needed hospitalization and intensive care unit (ICU) admission. The aim of the present study was to describe the communication and visiting policies of Italian intensive care units (ICUs) during the first COVID-19 pandemic wave and national lockdown and compare these data with prepandemic conditions. Methods: A national web-based survey was conducted among 290 Italian hospitals. Each ICU (active between February 24 and May 31, 2020) was encouraged to complete an individual questionnaire inquiring the hospital/ICU structure/organization, communication/visiting habits and the role of clinical psychology prior to, and during the first COVID-19 pandemic wave. Results: Two hundred and nine ICUs from 154 hospitals (53% of the contacted hospitals) completed the survey (202 adult and 7 pediatric ICUs). Among adult ICUs, 60% were dedicated to COVID-19 patients, 21% were dedicated to patients without COVID-19 and 19% were dedicated to both categories (Mixed). A total of 11,102 adult patients were admitted to the participating ICUs during the study period and only approximately 6% of patients received at least one visit. Communication with family members was guaranteed daily through an increased use of electronic devices and was preferentially addressed to the same family member. Compared to the prepandemic period, clinical psychologists supported physicians more often regarding communication with family members. Fewer patients received at least one visit from family members in COVID and mixed-ICUs than in non-COVID ICUs, l (0 [0–6]%, 0 [0–4]% and 11 [2–25]%, respectively, p < 0.001). Habits of pediatric ICUs were less affected by the pandemic. Conclusions: Visiting policies of Italian ICUs dedicated to adult patients were markedly altered during the first COVID-19 wave. Remote communication was widely adopted as a surrogate for family meetings. New strategies to favor a family-centered approach during the current and future pandemics are warranted

    Radio detection of cosmic ray ait showers with LOPES

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    The accuracy of signal measurement with the water Cherenkov detectors of the Pierre Auger Observatory

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    Le spectre des rayons cosmiques aux énergies extrêmes (les données de l'Observatoire Pierre Auger)

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    L'observatoire Pierre Auger est dédié à l'étude des rayons cosmiques d'ultra haute énergie. L'observatoire utilise une technique hybride,afin d'obtenir une très bonne précision sur les mesures. Dans ce travail nous avons étudié les performances des détecteur et évalué l'efficacité de l'électronique et du trigger. Nous avons optimisé la sélection des événements et avons estimé l'acceptance du détecteur. Les incertitudes de la reconstruction des événements ont été évaluées et propagées au spectre en énergie mesuré. Nous avons prouvé que quelques stations, actuellement non considérées comme participant aux événements, peuvent y être inclues. Nous avons étudié l'effet de la perte de signal d'un des trois photomultiplicateurs, ainsi que l'effet de la saturation des canaux des ADC ou du photomultiplicateur sur la qualité de la reconstruction. L'incertitude de reconstruction a été également étudiée dans le cas d'événements normaux en suivant une méthode basée sur la fluctuations des signaux, pour contre-vérifier les résultats obtenus en utilisant les incertitudes des paramètres de fonction d'ajustement. Une évaluation de l'efficacité du trigger a été également effectuée dans le cas où un des trois photomultiplicateurs serait absent. Nous avons prouvé que les problèmes instrumentaux réduisent seulement l'efficacité pour des événements dont l'énergie est inférieure au seuil de l'expérience et n'affectent pas la reconstruction de façon significative. En outre ce travail montre pour la première fois que les incertitudes de reconstruction des données du détecteur de surface ne changent pas l'indice de la loi de puissance du spectre mesuré des rayons cosmiques.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

    Cosmic ray composition and hadronic interactions in the knee region

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