5,813 research outputs found

    Emc aerospace systems analysis Interim scientific report

    Get PDF
    Analysis and data requirements for solving potential aerospace electromagnetic compatibility problem

    Arsenic in rice agrosystems (water, soil and rice plants) in Guayas and Los Rios provinces, Ecuador

    Get PDF
    Geogenic arsenic (As) can accumulate and reach high concentrations in rice grains, thus representing a potential threat to human health. Ecuador is one of the main consumers of rice in South America. However, there is no information available about the concentrations of As in rice agrosystems, although some water bodies are known to contain high levels of the element. We carried out extensive sampling of water, soil, rice plants and commercial rice (obtained from local markets). Water samples were analysed to determine physico-chemical properties and concentrations of dissolved arsenic. Soil samples were analysed to determine total organic C, texture, total Fe and amorphous Fe oxyhydroxides (Fe-ox), total arsenic (tAs) and the bioavailable fraction (As-Me). The different plant parts were analysed separately to determine total (tAs), inorganic (iAs) and organic arsenic (oAs). Low concentrations of arsenic were found in samples of water (generally 80%) in all parts of the rice plants. (C) 2016 Elsevier B.V. All rights reserved

    Procedures in the biochemical estimation of age of vertebrates

    Full text link
    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147143/1/pope0152.pd

    Temperature dependence of tropospheric ozone under NOx reductions over Germany

    Get PDF
    Due to the strong temperature dependence of surface ozone concentrations (O3), future warmer conditions may worsen ozone pollution levels despite continued efforts on emission controls of ozone precursors. Using longterm measurements of hourly O3 concentrations co-located with NOx concentrations in stations distributed throughout Germany, we assess changes in the climate penalty in summertime, defined as the slope of ozonetemperature relationship during the period 1999?2018. We find a stronger temperature sensitivity in the urban stations over the southwestern regions, especially in the first period of the study (1999?2008). We show a decrease in the climate penalty in most of stations during the second period of the study (2009?2018), with some exceptions (e.g. Berlin) where the climate penalty did not show significant changes. A key motivation of this study is to provide further insights into the impacts of NOx reductions in the O3-temperature relationship. For that, we propose a statisti-cal approach based on Generalized Additive Models (GAMs) to describe ozone production rates, inferred from hourly observations, as a function of NOx and temperature, among other variables relevant during the O3 production. The GAMs confirm lower O3 production rates during the second period (2009?2018) at most of the stations and a decreasing sensitivity to temperature. We observe that a large number of stations are transitioning to NOx-limited chemistry, consistent with a decreasing temperature dependence of O3 at moderate-high temperatures as a result of sustained NOx reductions. Moreover, the GAMs results showed changes in the shape of the function representing the O3-temperature relationship when comparing the first and second period, which suggest changes in VOC influencing the temperature dependence of O3. From these results, we infer effective VOC reductions over time that have also contributed to the observed decrease of O3 production rates. Thus, our analysis indicates that emissions reductions have been effective in a number of stations, particularly in the southwestern regions. However, we notice that in a few stations (e.g. Berlin) additional emission reductions should be required to effectively mitigate the temperature dependence of O3

    Office paper recyclability: first recycling

    Get PDF
    Paper recyclability implies in the paper capacity to be recycled maintaining its properties to the maximum. Four commercial papers from Argentina and Brazil were studied, including three eucalyptus kraft (A, B, C) and one sugar cane bagasse soda-AQ (D), all with different bleaching processes. Their physical and chemical properties and a first laboratory recycling were evaluated. A refining of the pulp with a PFI mill, applying two energy levels at two different intensities - measured by number of revolutions and load - was accomplished to reach the same °SR (between 30 and 40, approximately). The refining energy and the yield were registered in each case. The properties of laboratory handsheets, and the aging to 24, 48, 72 and 144 hours were evaluated. The statistical analysis of the results indicates that the properties of the initial eucalyptus papers were similar, whereas they were generally inferior in the case of the bagasse paper. The bagasse and eucalyptus papers presented similar initial whiteness, but the first one had a higher reversion than the others. Once repulped, the eucalyptus papers A, B and C required, respectively, 4, 7 and 10 times greater energy than D, to obtain the same °SR. In all cases, the required energy to achieve the same °SR is slightly greater with the smaller refining intensity. The physical properties of the handsheets from the first recycle of paper D were, in general, lower. Among eucalyptus papers, B showed a slightly higher resistance and C, a slightly lower one. The mechanical properties of pulp sheets A, and D to a lesser extension, were more affected by the refining intensity than the rest, indicating a higher sensitivity of the fibers. The whiteness of the sheets of pulp B is lower than the rest. Opacity and light scattering coefficient of the sheets of pulp C were much higher than those of the other pulps.Fil: Benitez, Julieta Beatriz. Universidad Nacional de Misiones; ArgentinaFil: Koga, Mariza E. T.. Instituto de Pesquisas Tecnológicas de São Paulo (ipt); BrasilFil: Otero D'Almeida, Maria L.. Instituto de Pesquisas Tecnológicas de São Paulo (ipt); BrasilFil: Felissia, Fernando Esteban. Universidad Nacional de Misiones; ArgentinaFil: Park, Song W.. Escola Politecnica, Universidad de Sao Paulo (usp); BrasilFil: Area, Maria Cristina. Universidad Nacional de Misiones; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
    corecore