1. Determining the Aethalometer multiple scattering enhancement factor C from the filter loading parameterLuca Ferrero, Niccolò Losi, Martin Rigler, Asta Gregorič, C. Colombi, L. D'Angelo, E. Cuccia, A. M. Cefalì, I. Gini, A. Doldi, 2024, izvirni znanstveni članek Opis: Light-absorbing aerosols heat the atmosphere; an accurate quantification of their absorption coefficient is mandatory. However, standard reference instruments (CAPS, MAAP, PAX, PTAAM) are not always available at each measuring site around the world.
By integrating all previous published studies concerning the Aethalometers, the AE33 filter loading parameter, provided by the dual-spot algorithm, were used to determine the multiple scattering enhancement factor from the Aethalometer itself (hereinafter CAE) on an yearly and a monthly basis. The method was developed in Milan, where Aethalometer measurements were compared with MAAP data; the comparison showed a good agreement in terms of equivalent black carbon (R2 = 0.93; slope = 1.02 and a negligible intercept = 0.12 μg m−3) leading to a yearly experimental multiple scattering enhancement factor of 2.51 ± 0.04 (hereinafter CMAAP). On a yearly time base the CAE values obtained using the new approach was 2.52 ± 0.01, corresponding to the experimental one (CMAAP). Considering the seasonal behavior, higher experimental CMAAP and computed CAE values were found in summer (2.83 ± 0.12) whereas, the lower ones in winter/early-spring (2.37 ± 0.03), in agreement with the single scattering albedo behavior in the Po Valley.
Overall, the agreement between the experimental CMAAP and CAE showed a root mean squared error (RMSE) of just 0.038 on the CMAAP prediction, characterized by a slope close to 1 (1.001 ± 0.178), a negligible intercept (−0.002 ± 0.455) and a high degree of correlation (R2 = 0.955). From an environmental point of view, the application of a dynamic (space/time) determination of CAE increases the accuracy of the aerosol heating rate (compared to applying a fixed C value) up to 16 % solely in Milan, and to 114 % when applied in the Arctic at 80°N.
Ključne besede: aethalometer, C factor, loading parameter, MAAP, heating rate
Objavljeno v RUNG: 02.02.2024; Ogledov: 1993; Prenosov: 16
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2. O[sub]2 loaded germanosilicate optical fibers : experimental in situ investigation and ab initio simulation study of GLPC evolution under irradiationImène Reghioua, Luigi Giacomazzi, Antonino Alessi, Blaž Winkler, Layla Martin-Samos, Sylvain Girard, Diego Di Francesca, Mattia Fanetti, Nicolas Richard, Matjaž Valant, 2022, izvirni znanstveni članek Ključne besede: optical fiber, O2 loading, point defects
Objavljeno v RUNG: 25.04.2022; Ogledov: 2516; Prenosov: 30
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Gradivo ima več datotek! Več... |
3. Temporal and spatial patterns of zinc and iron accumulation during barley (Hordeum vulgare L.) grain development. Journal of agricultural and food chemistry.Amelie Detterbeck, Paula Pongrac, Daniel Persson, Katarina Vogel-Mikuš, Mitja Kelemen, Primož Vaupetič, Primož Pelicon, Iztok Arčon, Søren Husted, Jan Kofod Shjoerring, Stephan Clemens, 2020, izvirni znanstveni članek Opis: Breeding and engineering of biofortified crops will benefit from a better understanding of bottlenecks controlling
micronutrient loading within the seeds. However, few studies have addressed the changes in micronutrient concentrations,
localization, and speciation occurring over time. Therefore, we studied spatial patterns of zinc and iron accumulation during grain
development in two barley lines with contrasting grain zinc concentrations. Microparticle-induced-X-ray emission and laser ablationinductively
coupled plasma mass spectrometry were used to determine tissue-specific accumulation of zinc, iron, phosphorus, and
sulfur. Differences in zinc accumulation between the lines were most evident in the endosperm and aleurone. A gradual decrease in
zinc concentrations from the aleurone to the underlying endosperm was observed, while iron and phosphorus concentrations
decreased sharply. Iron co-localized with phosphorus in the aleurone, whereas zinc co-localized with sulfur in the sub-aleurone. We
hypothesize that differences in grain zinc are largely explained by the endosperm storage capacity. Engineering attempts should be
targeted accordingly.
Ključne besede: barley (Hordeum vulgare L.), biofortification, grain development, grain loading, LA-ICP-MS, μ-PIXE
Objavljeno v RUNG: 20.10.2020; Ogledov: 3716; Prenosov: 0
Gradivo ima več datotek! Več... |
4. STUDY OF ATMOSPHERIC AEROSOL PROPERTIES IN THE VIPAVA VALLEYLonglong Wang, doktorska disertacija Opis: The aim of the dissertation was to study aerosol loading distributions and properties over the Vipava valley, a representative hot-spot for complex mixtures of different aerosol types of both anthropogenic and natural origin.
An infrared Mie and a two-wavelength polarization Raman lidar systems
were used as main detection tools. The polarization Raman lidar, which
provides the capability to extract the extinction coefficient, backscatter coefficients, depolarization ratio, backscatter Ångström exponent, lidar ratio and
water vapor mixing ratio profiles, was itself designed, built and calibrated as
a part of this thesis. Lidar data, combined with in-situ measurements, was
used to determine detailed information on different aerosol types. Vertical
profiles of aerosol mass concentration were extracted from the Mie lidar data
taken in April 2016, where the in-situ measurements of aerosol size distribution and number concentration as well as aerosol absorption coefficient and black carbon mass concentration were used to estimate the mass extinction efficiency (MEE). Aerosol morphology and chemical composition determined by SEM-EDX on sampled particles were used for the identification
of primary aerosol types. Two cases with different atmospheric conditions
(long range mineral dust transport and local biomass burning) and different
expected the dominant presence of specific aerosol types (mineral dust and
soot) were investigated in more detail. They revealed significantly different
aerosol properties and distributions within the valley, affecting radiative heat
exchange.
A more detailed investigation of aerosol properties throughout the troposphere in different atmospheric conditions was made possible by the two-wavelength polarization Raman lidar system, deployed in Ajdovščina (town
of Vipava valley) from September 2017. Using its aerosol identification capabilities, based on particle depolarization ratio and lidar ratio measurements,
it was possible to identify predominant aerosol types in the observed atmospheric structures, for example in different atmospheric layers in the case of
the stratified atmosphere. Primary anthropogenic aerosols within the valley were found to be mainly emitted from two sources: individual domestic
heating systems, which mostly use biomass fuel and traffic. Natural aerosols,
transported over large distances, such as mineral dust and sea salt, were observed both above and entering into the planetary boundary layer. Backscatter contribution of each aerosol type was separated and the corresponding
extinction contribution was derived from lidar observations.
Ključne besede: Vipava valley, aerosol distribution, aerosol characterization, lidar
remote sensing, in-situ measurements, aerosol loading.
Objavljeno v RUNG: 23.10.2018; Ogledov: 8615; Prenosov: 164
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7. The filter loading effect by ambient aerosols in filter absorption photometers depends on the mixing state of the sampled particlesLuka Drinovec, Asta Gregorič, Peter Zotter, Robert Wolf, Emily Anne Bruns, André S.H. Prévôt, Jean-Eudes Petit, Olivier Favez, JEAN SCIARE, Ian J. Arnold, Rajan K. Chakrabarty, Hans Moosmüller, Agnes Fülöp-Miller, Griša Močnik, 2016, izvirni znanstveni članek Ključne besede: black carbon, mixing state, Aethalometer, filter-loading effect
Objavljeno v RUNG: 02.11.2016; Ogledov: 6424; Prenosov: 284
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