1,393 research outputs found

    Revised predictions of neutrino fluxes from Pulsar Wind Nebulae

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    Several Pulsar Wind Nebulae (PWNe) have been detected in the TeV band in the last decade.The TeV emission is typically interpreted in a purely leptonic scenario, but this usually requires that the magnetic field in the Nebula be much lower than the equipartition value and the assumption of an enhanced target radiation at IR frequencies. In this work we consider the possibility that, in addition to the relativistic electrons, also relativistic hadrons are present in these nebulae. Assuming that part of the emitted TeV photons are of hadronic origin, we compute the associated flux of 1100\sim 1-100 TeV neutrinos. We use the IceCube non detection to put constraints on the fraction of TeV photons that might be contributed by hadrons and estimate the number of neutrino events that can be expected from these sources in ANTARES and in KM3Net.Comment: Submitted to ApJ, 12 pages, 3 figure

    Shortcut biological nitrogen removal (SBNR) in microbial fuel cells (MFCs)

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    Microbial Fuel Cells (MFCs) represent nowadays a promising technology for the treatment of industrial wastewater. In this work the Shortcut Nitritation/Denitritation process in H-type MFC was investigated. The cell was fed by sodium acetate and fumaric acid, as organic carbon source, and ammonium sulphate, sodium nitrite and sodium nitrate as nitrogen source. Anaerobic digestion supernatant (digestate) was used as bacterial source. Batch tests were performed at a TOC/N ratio of 0.35, and Total Organic Carbon (TOC), pH and Open Circuit Voltage (OCV) were daily monitored. High organic carbon removal (up to 85%) in short time (within 6 days) were achieved. The nitritation proved to be independent of organic carbon amount and composition: an ammonium content reduction of about 45% was observed. Regarding the denitritation step, an almost quantitative removal of nitrite and nitrate was observed when fumaric acid was used as a carbon source

    Photolysis of in-situ electrogenerated hydrogen peroxide for the degradation of emerging pollutants

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    This study investigates the degradation of paracetamol, an emerging contaminant widely used as pain and fever reliever, by means of hydrogen peroxide either alone or in combination with UV-C photolysis. In particular, we provide a comparison between the performance of both commercial and electrogenerated H2O2 whose production has been achieved by galvanostatic electrolysis in undivided reactor with a gas diffusion cathode. The performance of the treatments has been assessed in terms of both pollutant decay and mineralization. The influence of the H2O2 to paracetamol molar ratio is discussed. The results show that the electrogenerated hydrogen peroxide, when activated by UV-C irradiation, results in faster degradation and mineralization of paracetamol. However, under the conditions adopted, complete depletion of the total organic carbon (TOC) has never been attained

    Shortcut Biological Nitrogen Removal (SBNR) in an MFC anode chamber under microaerobic conditions. The effect of C/N ratio and kinetic study

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    In this work, the feasibility of the Shortcut Biological Nitrogen Removal (SBNR) in the anodic chamber of a Microbial Fuel Cell (MFC) was investigated. Thirty day experiments were carried out using synthetic wastewaters with a Total Organic Carbon vs. nitrogen ratio (TOC/N) ranging from 0.1 to 1. Ammonium, nitrite, nitrate, pH, and TOC were daily monitored. Results showed that microaerobic conditions in the anodic chamber favored the development of nitritation reaction, due to oxygen transfer from the cathodic chamber through the membrane. Nitritation was found to depend on TOC/N ratio: at TOC/N equal to 0.1 an ammonium removal efficiency of up to 76% was observed. Once the oxygen supply to the cathodic chamber was stopped, denitritation occurred, favored by an increase of the TOC/N ratio: a nitrite removal of 80.3% was achieved at TOC/N equal to 0.75. The presence of nitrogen species strongly affected the potential of the electrochemical system: in the nitritation step, the Open Circuit Voltage (OCV) decreased from 180 mV to 21 mV with the decrease of the TOC/N ratio in the investigated range. Lower OCV values were observed in the denitritation steps since the organic carbon acted as the energy source for the conversion of nitrite to nitrogen gas. A kinetic analysis was also performed. Monod and Blackman models described the ammonium and the organic carbon removal processes well during the nitritation step, respectively, while Blackman-Blackman fitted experimental results of the denitritation step better

    A first search for coincident gravitational waves and high energy neutrinos

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    Investigation of the synergistic effect of hydrogen peroxide and ultrasound on the photocatalytic treatment under visible light of dyes wastewater

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    A photocatalytic process under visible light irradiation (LED lamp 13 W) assisted by ultrasound and hydrogen peroxide was investigated, aiming at enhancing the hydroxyl radical production compared to simple photocatalysis. Several parameters, including ultrasound power and H2O2 concentration, were investigated in the degradation of Rhodamine B. Fe doped TiO2 synthesized by the solid-state method was used as the photocatalyst. The synergistic effects between photocatalysis, ultrasound, and H2O2 were studied, and the absence of synergy between photocatalysis and ultrasound was demonstrated. Instead, a synergistic effect was observed between photocatalysis and hydrogen peroxide addition, in fact, the combination of photocatalysis with H2O2 was demonstrated to totally remove the Rhodamine B (5 ppm) in 2 h, as contaminant removal was greater (by 50 %) when the two treatments were used simultaneously than the removal observed in the individual treatments, attributable to the Fenton reaction that promoted the hydroxyl radicals production

    Perspectives in nanotechnology based innovative applications for the environment

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    In this perspective paper, the actual trends in nanotechnology based innovative applications for the environment are analyzed and possible future trends were studied. On the basis of the relevant topics of the NINE congress held in Rome, 2016, a bibliographical search was performed on papers fitting in one or more categories within the last 5 years, that is: 1. Nanosensors and bionanosensors for environmental characterization and monitoring 2. Technologies for the production of Nanomaterials for the environment 3. Nanostructured materials for advanced remediation processes 4. Nano-based water and wastewater treatment processes 5. Membrane processes for the environment 6. Health and safety issues concerning Nanomaterials 7. Education on Environmental Engineering and Nanotechnology. A yearly count of contributions was performed and taken as an indicator of interest of the specific topic within the wide broad scientific community. In a second step, the resulting data was analyzed by regression techniques to estimate the trend in the next future and to evaluate the next challenges within the international research framework
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