261 research outputs found

    Solar photocatalytic degradation of polyethylene terephthalate nanoplastics: Evaluation of the applicability of the TiO2/MIL-100(Fe) composite material

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    For the first time, TiO2/MIL-100(Fe) photocatalysts supported on perlite mineral particles prepared by the solvothermal/microwave methods and post-annealing technique were tested in the degradation of polyethylene terephthalate nanoplastics (PET NPs). Powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectroscopy, N2 physisorption, photoluminescence emission spectroscopy, photocurrent response, and electrochemical impedance spectroscopy were used to characterize the as-prepared materials. The response surface methodology approach was used to study the effects: pH of the NPs suspension and incorporated amount of MIL-100(Fe) on the TiO2/MIL-100(Fe) catalyst to optimize the photocatalytic degradation of the PET NPs under simulated solar light. The degradation of the PET NPs was evaluated by measuring turbidity and carbonyl index (FTIR) changes. The total organic carbon (TOC) in the solution during the degradation of the PET NPs was assessed to measure NPs oxidation into water-soluble degradation by-products. The active species involved in the photocatalytic degradation of PET NPs by the TiO2/MIL-100(Fe) composite was further examined based on trapping experiments. The use of 12.5 wt% TiO2/MIL-100(Fe) catalyst showed improved photocatalytic efficacy in the oxidation of PET NPs at pH 3 under simulated sunlight compared to bare TiO2. The increase in the carbonyl index (CI = 0.99), the reduction in the turbidity ratio (0.454), and the increase in the content of TOC released (3.00 mg/L) were possible with 12.5 wt% TiO2/MIL-100(Fe) material. In contrast, the PET NPs were slowly degraded by TiO2-based photocatalysis (CI = 0.96, turbidity ratio = 0.539, released TOC = 2.12 mg/L). The mesoporous TiO2/MIL-100(Fe) composites with high specific surface area, capacity to absorb visible light, and effective separation of photogenerated electron-hole charges clearly demonstrated the enhancement of the photocatalytic performance in the PET NPs degradation under simulated solar light

    Aedes albopictus in northeast Mexico: An update on adult distribution and first report of parasitism by Ascogregarina taiwanensis

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    ABSTRACT Background & objectives: Aedes albopictus has been known as efficient vector of dengue in Asian countries and its wide displacement of Ae. aegypti has been documented in many parts of the world. The present survey was carried out to update the distribution of Ae. albopictus in northeast Mexico and to report the first record of parasitism of mosquitoes by Ascogregarina taiwanensis in Mexico

    Production properties of K*(892) vector mesons and their spin alignment as measured in the NOMAD experiment

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    First measurements of K*(892) mesons production properties and their spin alignment in nu_mu charged current (CC) and neutral current (NC) interactions are presented. The analysis of the full data sample of the NOMAD experiment is performed in different kinematic regions. For K*+ and K*- mesons produced in nu_mu CC interactions and decaying into K0 pi+/- we have found the following yields per event: (2.6 +/- 0.2 (stat.) +/- 0.2 (syst.))% and (1.6 +/- 0.1 (stat.) +/- 0.1 (syst.))% respectively, while for the K*+ and K*- mesons produced in nu NC interactions the corresponding yields per event are: (2.5 +/- 0.3 (stat.) +/- 0.3 (syst.))% and (1.0 +/- 0.3 (stat.) +/- 0.2 (syst.))%. The results obtained for the rho00 parameter, 0.40 +/- 0.06 (stat) +/- 0.03 (syst) and 0.28 +/- 0.07 (stat) +/- 0.03 (syst) for K*+ and K*- produced in nu_mu CC interactions, are compared to theoretical predictions tuned on LEP measurements in e+e- annihilation at the Z0 pole. For K*+ mesons produced in nu NC interactions the measured rho00 parameter is 0.66 +/- 0.10 (stat) +/- 0.05 (syst).Comment: 20 p

    Improving the delivery and efficiency of fungus-impregnated cloths for control of adult Aedes aegypti using a synthetic attractive lure

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    Abstract Background Entomopathogenic fungi are highly promising agents for controlling Aedes aegypti mosquitoes. Deploying fungus-impregnated black cloths in PET traps efficiently reduced Ae. aegypti female survival rates under intra-domicile conditions. With the aim of further increasing the effectiveness of the traps, the addition of attractive lures to fungus-impregnated traps was evaluated. Methods Black cloths were suspended inside 2 l plastic bottles called “PET traps”. These traps were placed in rooms simulating human residences. The first experiments evaluated the attraction of mosquitoes to PET traps with black cloths covered in adhesive film with and without synthetic lures (AtrAedes™). Traps were left in the test rooms for either 24 or 48 h. The attractiveness of the lures over time was also evaluated. The efficiency of PET traps with fungus-impregnated black cloths associated with lures was compared to that of traps without lures. Results The highest percentage of captured mosquitoes (31 and 66%) were observed in PET traps with black cloths covered in adhesive film + attractive lure maintained in test rooms for 24 h and 48 h, respectively. Black cloths covered in adhesive film captured 17 or 36% of the mosquitoes at 24 h and 48 h, respectively. The attractiveness of the lures fell gradually over time, capturing 37% after 5 days on the bench and 22% of the mosquitoes after 30 days exposure to ambient conditions. Associating attractive synthetic lures with black cloths impregnated with M. anisopliae placed in test rooms for 120 h reduced mean survival to 32%, whilst black cloths impregnated with M. anisopliae without lures resulted in a 48% survival rate. Using Beauveria bassiana in the traps resulted in a 52% reduction in mosquito survival, whilst combining Beauveria and AtrAedes resulted in a 36% survival rate. PET traps impregnated with fungus + AtrAedes resulted in similar reductions in survival when left in the rooms for 24, 48, 72 or 120 h. Conclusions AtrAedes increased attractiveness of PET traps with black cloths under intra-domicile conditions and when associated with M. anisopliae or B. bassiana, significantly reduced Aedes survival. This strategy will reduce the number of PET traps necessary per household

    Prediction of Neutrino Fluxes in the NOMAD Experiment

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    The method developed for the calculation of the flux and composition of the West Area Neutrino Beam used by NOMAD in its search for neutrino oscillations is described. The calculation is based on particle production rates computed using a recent version of FLUKA and modified to take into account the cross sections measured by the SPY and NA20 experiments. These particles are propagated through the beam line taking into account the material and magnetic fields they traverse. The neutrinos produced through their decays are tracked to the NOMAD detector. The fluxes of the four neutrino flavours at NOMAD are predicted with an uncertainty of about 8% for nu(mu) and nu(e), 10% for antinu(mu), and 12% for antinu(e). The energy-dependent uncertainty achieved on the R(e, mu) prediction needed for a nu(mu)->nu(e) oscillation search ranges from 4% to 7%, whereas the overall normalization uncertainty on this ratio is 4.2%.Comment: 43 pages, 20 figures. Submitted to Nucl. Phys.

    Final NOMAD results on nu_mu->nu_tau and nu_e->nu_tau oscillations including a new search for nu_tau appearance using hadronic tau decays

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    Results from the nu_tau appearance search in a neutrino beam using the full NOMAD data sample are reported. A new analysis unifies all the hadronic tau decays, significantly improving the overall sensitivity of the experiment to oscillations. The "blind analysis" of all topologies yields no evidence for an oscillation signal. In the two-family oscillation scenario, this sets a 90% C.L. allowed region in the sin^2(2theta)-Delta m^2 plane which includes sin^2(2theta)<3.3 x 10^{-4} at large Delta m^2 and Delta m^2 < 0.7 eV^2/c^4 at sin^2(2theta)=1. The corresponding contour in the nu_e->nu_tau oscillation hypothesis results in sin^2(2theta)<1.5 x 10^{-2} at large Delta m^2 and Delta m^2 < 5.9 eV^2/c^4 at sin^2(2theta)=1. We also derive limits on effective couplings of the tau lepton to nu_mu or nu_e.Comment: 46 pages, 16 figures, Latex, to appear on Nucl. Phys.

    Inclusive production of ρ0(770),f0(980)\rho^{0}(770), f_0(980) and f2(1270)f_2(1270) mesons in νμ\nu_{\mu} charged current interactions

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    The inclusive production of the meson resonances ρ0(770)\rho^{0}(770), f0(980)f_0(980) and f2(1270)f_2(1270) in neutrino-nucleus charged current interactions has been studied with the NOMAD detector exposed to the wide band neutrino beam generated by 450 GeV protons at the CERN SPS. For the first time the f0(980)f_{0}(980) meson is observed in neutrino interactions. The statistical significance of its observation is 6 standard deviations. The presence of f2(1270)f_{2}(1270) in neutrino interactions is reliably established. The average multiplicity of these three resonances is measured as a function of several kinematic variables. The experimental results are compared to the multiplicities obtained from a simulation based on the Lund model. In addition, the average multiplicity of ρ0(770)\rho^{0}(770) in antineutrino - nucleus interactions is measured.Comment: 23 pages, 14 figures, 8 tables. To appear in Nucl. Phys.

    Search for nu(mu)-->nu(e) Oscillations in the NOMAD Experiment

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    We present the results of a search for nu(mu)-->nu(e) oscillations in the NOMAD experiment at CERN. The experiment looked for the appearance of nu(e) in a predominantly nu(mu) wide-band neutrino beam at the CERN SPS. No evidence for oscillations was found. The 90% confidence limits obtained are delta m^2 < 0.4 eV^2 for maximal mixing and sin^2(2theta) < 1.4x10^{-3} for large delta m^2. This result excludes the LSND allowed region of oscillation parameters with delta m^2 > 10 eV^2.Comment: 19 pages, 8 figures. Submitted to Phys. Lett.

    Search for the exotic Θ+\Theta^+ resonance in the NOMAD experiment

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    A search for exotic Theta baryon via Theta -> proton +Ks decay mode in the NOMAD muon neutrino DIS data is reported. The special background generation procedure was developed. The proton identification criteria are tuned to maximize the sensitivity to the Theta signal as a function of xF which allows to study the Theta production mechanism. We do not observe any evidence for the Theta state in the NOMAD data. We provide an upper limit on Theta production rate at 90% CL as 2.13 per 1000 of neutrino interactions.Comment: Accepted to European Physics Journal

    A Precise Measurement of the Muon Neutrino-Nucleon Inclusive Charged Current Cross-Section off an Isoscalar Target in the Energy Range 2.5 < E_\nu < 40 GeV by NOMAD

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    We present a measurement of the muon neutrino-nucleon inclusive charged current cross-section, off an isoscalar target, in the neutrino energy range 2.5Eν402.5 \leq E_\nu \leq 40 GeV. The significance of this measurement is its precision, ±4\pm 4% in 2.5Eν102.5 \leq E_\nu \leq 10 GeV, and ±2.6\pm 2.6% in 10Eν4010 \leq E_\nu \leq 40 GeV regions, where significant uncertainties in previous experiments still exist, and its importance to the current and proposed long baseline neutrino oscillation experiments.Comment: 14 pages, 3 figures, submitted to Phys.Lett.
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