219 research outputs found
Simulation tools for computer-aided design and numerical investigations of high-power gyrotrons
Modelling and simulation are essential tools for computer-aided design (CAD), analysis and optimization of high-power gyrotrons used as radiation sources for electron cyclotron resonance heating (ECRH) and current drive (ECCD) of magnetically confined plasmas in the thermonuclear reactor ITER. In this communication, we present the current status of our simulation tools and discuss their further development
Effect of superficial treatment with new natural antioxidant on salmon (Salmo salar) lipid oxidation
Lipid oxidation is one of the main factors responsible for the quality loss in refrigerated and frozen stored fish products. The aim of the study was to evaluate the effect of superficial treatment of Atlantic salmon (Salmo salar) with dihydroquercetin (DHQ) solutions on the hydrolytic and oxidative changes in fish lipids during refrigerated storage. It was found that treatment with DHQ solution (1.0 g l−1) reduced approximately twice the free fatty acids content of chilled stored salmon. After 11 days of storage at 1 °С, the contents of hydroperoxides (HPO) and 2-thiobarbituric acid reactive substances (TBARS) of these samples decreased with 45.00 and 0.91 mg MDA/kg, respectively. The share of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) in control and experimental samples did not differ significantly (P>0.05). Results obtained show that the superficial treatment of salmon with DHQ solution (1.0 g l−1) delayed the hydrolytic and oxidative changes in fish lipids significantly, thus preserving the salmon freshness up to 11 days of storage at 1 °С
Measurements of , K, p and spectra in proton-proton interactions at 20, 31, 40, 80 and 158 GeV/c with the NA61/SHINE spectrometer at the CERN SPS
Measurements of inclusive spectra and mean multiplicities of ,
K, p and produced in inelastic p+p interactions at
incident projectile momenta of 20, 31, 40, 80 and 158 GeV/c ( 6.3,
7.7, 8.8, 12.3 and 17.3 GeV, respectively) were performed at the CERN Super
Proton Synchrotron using the large acceptance NA61/SHINE hadron spectrometer.
Spectra are presented as function of rapidity and transverse momentum and are
compared to predictions of current models. The measurements serve as the
baseline in the NA61/SHINE study of the properties of the onset of
deconfinement and search for the critical point of strongly interacting matter
Measurements of , , , and proton production in proton-carbon interactions at 31 GeV/ with the NA61/SHINE spectrometer at the CERN SPS
Measurements of hadron production in p+C interactions at 31 GeV/c are
performed using the NA61/ SHINE spectrometer at the CERN SPS. The analysis is
based on the full set of data collected in 2009 using a graphite target with a
thickness of 4% of a nuclear interaction length. Inelastic and production cross
sections as well as spectra of , , p, and are
measured with high precision. These measurements are essential for improved
calculations of the initial neutrino fluxes in the T2K long-baseline neutrino
oscillation experiment in Japan. A comparison of the NA61/SHINE measurements
with predictions of several hadroproduction models is presented.Comment: v1 corresponds to the preprint CERN-PH-EP-2015-278; v2 matches the
final published versio
Glycerol valorization: dehydration to acrolein over silica-supported niobia catalysts
The catalytic dehydration of glycerol to acrolein is investigated over silica-supported niobia catalysts in a continuous fixed-bed gas-phase reactor. Various supported niobia catalysts are prepared and characterized using surface analysis and spectroscopic methods (XRD, UV–Vis, XPS, N2 adsorption), as well as with ammonia adsorption microcalorimetry. Good results are obtained with initial glycerol conversions of over 70% and with 50–70% selectivity to acrolein. We investigate the influence of changing the catalyst acid strength by varying the niobia content and catalyst calcination temperature. Glycerol conversion and acrolein selectivity depend on the surface acid strength. Catalyst deactivation by coking is also observed, but simple oxidative treatment in air restores the activity of the catalysts completely
Ir-Catalysed Nitrous Oxide (N2O) Decomposition:Effect of Ir Particle Size and Metal–Support Interactions
The effect of the morphology of Ir particles supported on γ-Al2O3, 8 mol%Y2O3-stabilized ZrO2 (YSZ), 10 mol%Gd2O3-doped CeO2 (GDC) and 80 wt%Al2O3–10 wt%CeO2–10 wt%ZrO2 (ACZ) on their stability on oxidative conditions, the associated metal–support interactions and activity for catalytic decomposition of N2O has been studied. Supports with intermediate or high oxygen ion lability (GDC and ACZ) effectively stabilized Ir nanoparticles against sintering, in striking contrast to supports offering negligible or low oxygen ion lability (γ-Al2O3 and YSZ). Turnover frequency studies using size-controlled Ir particles showed strong structure sensitivity, de-N2O catalysis being favoured on large catalyst particles. Although metallic Ir showed some de-N2O activity, IrO2 was more active, possibly present as a superficial overlayer on the iridium particles under reaction conditions. Support-induced turnover rate modifications, resulted from an effective double layer [Oδ−–δ+](Ir) on the surface of iridium nanoparticles, via O2− backspillover from the support, were significant in the case of GDC and ACZ
Proton-proton interactions and onset of deconfinement
The experiment of the NA61/SHINE Collaboration at the CERN SPS is performing a unique study of the phase diagram of strongly interacting matter by varying collision energy and nuclear mass number of colliding nuclei. In central Pb+Pb collisions, the experiment of the NA49 Collaboration found structures in the energy dependence of several observables in the energy range of the CERN SPS that had been predicted for the transition to a deconfined phase. New measurements of the NA61/SHINE Collaboration find intriguing similarities in p+p interactions for which no deconfinement transition is expected at the energies of the SPS. Possible implications will be discussed
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