1,720,994 research outputs found
Chromophores and chemical composition of brown carbon characterized at an urban kerbside by excitation-emission spectroscopy and mass spectrometry
No full textThe data in the Excel files are related to the publication Jiang et al., ACP, 2022. Each sheet of the Excel files corresponds to one plot in the publication as repeated below. The data originates mainly from Aqualog and FIGAERO-CIMS measurements. The figures and captions from the publication are shown in the following to allow for a good understanding of the data files. Jiang, F., Song, J., Bauer, J., Gao, L., Vallon, M., Gebhardt, R., Leisner, T., Norra, S., and Saathoff, H.: Chromophores and chemical composition of brown carbon characterized at an urban kerbside by excitation-emission spectroscopy and mass spectrometry, Atmos. Chem. Phys. Discuss. [preprint], https://doi.org/10.5194/acp-2022-465, in review, 2022
Sources of organic gases and aerosol particles and their roles in nighttime particle growth at a rural forested site in southwest Germany
No full textThe composition, sources and chemical transformation of volatile organic compounds (VOCs)
and organic aerosol (OA) particles were investigated during July–August 2021 at a rural forested site in southwest
Germany, 10 km north of the city of Karlsruhe. VOCs and semi-volatile OA particles were measured with
a proton-transfer-reaction mass spectrometer coupled to the CHemical Analysis of aeRosols ONline particle
inlet (CHARON–PTR-MS). The CHARON-measured OA mass accounted for 62+-18% on average of the total
OA mass (4.2+-2.8 μgm-3) measured concurrently with an aerosol mass spectrometer (AMS). The total concentrations
of measured VOCs ranged from 7.6 to 88.9 ppb with an average of 31.2+-13.4 ppb. Positive matrix
factorization (PMF) was used to identify major source factors of VOCs and OA particles. Three types of oxygenated
VOC (OVOC), namely aromatic OVOCs, biogenic OVOCs and aged OVOCs, contributed on average
11%+-9 %, 37%+-29% and 29%+-21% of total VOC concentrations, respectively. The results of AMS–PMF
indicated substantial contributions of oxygenated organic compounds to OA particle mass. Three secondary OA
(SOA) factors determined by CHARON–PMF analysis, namely aromatic SOA (5%7 %), daytime biogenic
SOA (17%+-17 %) and nighttime biogenic SOA (28%+-21 %), consistently showed high contributions to the
total CHARON-measured OA mass. Nighttime particle growth was observed regularly in this area, which was
mainly attributed to the semi-volatile organic compounds and organic nitrates formed from the oxidation of
monoterpenes and sesquiterpenes. This study presents the major sources, real-time transformations of VOCs and
OA particles, and nighttime particle formation characteristics for central European forested areas
Kinetics, SOA yields and chemical composition of secondary organic aerosol from β-caryophyllene ozonolysis with and without nitrogen oxides between 213 and 313 K
No full textThe data in the Excel file is related to the publication Gao et al., ACP, 2022. Each sheet of the Excel file corresponds to one plot in the publication. The data originates mainly from FIGAERO-CIMS and HR-ToF-AMS (both Aerodyne Inc.) measurements. “Kinetics, SOA yields and chemical composition of secondary organic aerosol from β-caryophyllene ozonolysis with and without nitrogen oxides between 213 and 313 K” Linyu Gao1,2; Junwei Song1,2; Claudia Mohr3; Wei Huang4; Magdalena Vallon1; Feng Jiang1,2; Thomas Leisner1,5; and Harald Saathoff1 1 Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany 2 Institute of Geography and Geoecology, Working Group for Environmental Mineralogy and Environmental System Analysis, Karlsruhe Institute of Technology, Karlsruhe, Germany 3 Department of Environmental Science, Stockholm University, Stockholm, Sweden 4 Institute for Atmospheric and Earth System Research / Physics, Faculty of Science, University of Helsinki, Helsinki, Finland 5 Institute of Environmental Physics, Heidelberg University, Heidelberg, Germany Correspondence to: Linyu Gao ([email protected]) and Dr. Harald Saathoff ([email protected]) Atmos. Chem. Phys. Discuss. [preprint], https://doi.org/10.5194/acp-2021-1067, in review, 2022. (accepted on April 4th, 2022
Light spectra measured inside the AIDA aerosol and cloud simulation chamber
No full textSpektren der Lichtquelle in der AIDA Aerosol und Wolkenkamme
Data sets for the research article "Ice nucleation ability of ammonium sulfate aerosol particles internally mixed with secondary organics" by Bertozzi et al. (2021) in Atmospheric Chemistry and Physics (ACP)
No full textThis repository contains the datasets used in the study "Ice nucleation ability of ammonium sulfate aerosol particles internally mixed with secondary organics"by Bertozzi et al. (2021) in Atmospheric Chemistry and Physics (ACP). Metadata are stored as headers in each file
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Volatility of secondary organic aerosol from β-caryophyllene ozonolysis between 213-313 K
No full textWe investigated secondary organic aerosol (SOA) from β-caryophyllene oxidation generated over 213-313 K from ozonolysis. Positive matrix factorization (PMF) was used to deconvolute the desorption data (thermograms) of SOA products detected by a chemical ionization mass spectrometer (FIGAERO-CIMS). A non-monotonic dependence of particle volatility (saturation concentration at 298 K, C_298K^*) on formation temperature (213-313 K) was observed, primarily due to temperature-dependent formation pathways of β-caryophyllene oxidation products. The PMF analysis grouped detected ions into 11 compound groups (factors) with characteristic volatility. These compound groups act as indicators for the underlying SOA formation mechanisms. Their different temperature response revealed that the relevant chemical pathways (e.g., autoxidation, oligomer formation, and isomer formation) had distinct optimal temperatures between 213–313 K, significantly beyond the effect of temperature-dependent partitioning. Furthermore, PMF-resolved volatility groups were compared with volatility basis set (VBS) distributions based on different vapor pressure estimation methods. The variation of the volatilities predicted by different methods is affected by highly oxidation oxygenated molecules, isomers and thermal decomposition of oligomers with long carbon chains. This work distinguishes multiple isomers and identifies compound groups of varying volatility, providing new insights into the temperature-dependent formation mechanisms of β-caryophyllene-derived SOA particles
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