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41.
The new instrument using a TC–BC (total carbon–black carbon) method for the online measurement of carbonaceous aerosols
Martin Rigler, Luka Drinovec, Gašper Lavrič, Anastasia Vlachou, André S. H. Prévôt, Jean-Luc Jaffrezo, IASONAS STAVROULAS, Jean Sciare, Judita Burger, Irena Krajnc, Janja Turšič, Anthony D. A. Hansen, Griša Močnik, 2020, original scientific article

Abstract: We present a newly developed total carbon analyzer (TCA08) and a method for online speciation of carbonaceous aerosol with a high time resolution. The total carbon content is determined by flash heating of a sample collected on a quartz-fiber filter with a time base between 20 min and 24 h. The limit of detection is approximately 0.3 µg C, which corresponds to a concentration of 0.3 µg C m−3 at a sample flow rate of 16.7 L min−1 and a 1 h sampling time base. The concentration of particulate equivalent organic carbon (OC) is determined by subtracting black carbon concentration, concurrently measured optically by an Aethalometer®, from the total carbon concentration measured by the TCA08. The combination of the TCA08 and Aethalometer (AE33) is an easy-to-deploy and low-maintenance continuous measurement technique for the high-time-resolution determination of equivalent organic and elemental carbon (EC) in different particulate matter size fractions, which avoids pyrolytic correction and the need for high-purity compressed gases. The performance of this online method relative to the standardized off-line thermo-optical OC–EC method and respective instruments was evaluated during a winter field campaign at an urban background location in Ljubljana, Slovenia. The organic-matter-to-organic-carbon ratio obtained from the comparison with an aerosol chemical speciation monitor (ACSM) was OM/OC=1.8, in the expected range.
Keywords: total carbon, aeroosl, black carbon, carbonaceous matter
Published in RUNG: 17.08.2020; Views: 2812; Downloads: 76
.pdf Full text (226,45 KB)

42.
Search for Axionlike-Particle-Induced Prompt γ -Ray Emission from Extragalactic Core-Collapse Supernovae with the Fermi Large Area Telescope
Manuel Meyer, Tanja Petrushevska, 2020, original scientific article

Abstract: During a core-collapse supernova (SN), axionlike particles (ALPs) could be produced through the Primakoff process and subsequently convert into γ rays in the magnetic field of the Milky Way. We do not find evidence for such a γ-ray burst in observations of extragalactic SNe with the Fermi Large Area Telescope (LAT). The SN explosion times are estimated from optical light curves and we find a probability of about ∼90% that the LAT observed at least one SN at the time of the core collapse. Under the assumption that at least one SN was contained within the LAT field of view, we exclude photon-ALP couplings ≳2.6×10−12 GeV−1 for ALP masses ma≲3×10−10 eV, improving previous limits from SN1987A by a factor of 2.
Keywords: darn matter, axions, axion-like particles, core-collapse supernovae
Published in RUNG: 15.06.2020; Views: 2480; Downloads: 77
.pdf Full text (30,47 MB)

43.
Towards ultrafast X-ray condensed matter physics with MHz repetition rate HHG sources
Jurij Urbančič, 2015, published scientific conference contribution abstract

Abstract: In recent years, an increasing number of ultrafast material science experiments are based on the use of table-top high-harmonic generation (HHG) lightsources [1,2]. Despite the huge success of these first experiments, a major drawback has been the limited repetition rate of these lightsources, in particular with respect to all types of photoemission experiments. Here, we combine newly developed high-repetition rate HHG sources [3,4] with state-of-the-art element-specific magneto-optical Kerr experiments. The chances and prospects for future ultrafast materials science experiments with these lightsources will be discussed.
Keywords: High Harmonic Generation, X-Rays, Condensed Matter
Published in RUNG: 22.05.2020; Views: 3141; Downloads: 0

44.
The Dark Side of the Matter
Gabrijela Zaharijas, 2019, other component parts

Keywords: Dark matter, cosmology
Published in RUNG: 17.05.2020; Views: 2726; Downloads: 0
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45.
46.
TeV dark matter search at the Galactic center with the CTA
Gabrijela Zaharijas, unpublished invited conference lecture

Keywords: gamma rays, dark matter, Cherenkov Telescope Array
Published in RUNG: 16.05.2020; Views: 2548; Downloads: 0
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47.
Search forγ-ray emission from dark matter particle interactions from theAndromeda and Triangulum galaxies with the Fermi Large Area Telescope
Gabrijela Zaharijas, 2019, original scientific article

Keywords: gamma rays, dark matter
Published in RUNG: 20.02.2020; Views: 2475; Downloads: 0
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48.
Uranium bearing dissolved organic matter in the porewaters of uranium contaminated lake sediments
Breda Novotnik, Wei Chen, R. Douglas Evans, 2018, original scientific article

Abstract: Uranium (U) mobility in the environment strongly depends on its oxidation state and the presence of complexing agents such as inorganic carbon, phosphates, and dissolved organic matter (DOM). Despite the importance of DOM in U mobility, the exact mechanism is still poorly understood. Therefore, the aim of our investigation was to characterise sediment porewater DOM in two lakes in Ontario, Canada (Bow and Bentley Lakes) that were historically contaminated with U and propose possible composition of UO2-bearing DOM. Depth profiles of U concentrations in porewaters and total sediment digests reveal U levels of up to 1.3 mg L−1 in porewater and up to 0.8 mg−1 g in sediment. Depth profiles of U did not correlate with Fe, Mn, SO4 2−, or Eh profiles. Therefore, porewater DOM was analysed and taken into consideration as the primary source of U mobility. Porewater DOM in each sediment section (1 cm sections, 20 cm core length) was analysed by high-resolution electrospray ionisation mass spectrometry. PCA analyses of porewater DOM mass spectra showed grouping and clear separation of DOM in sediment sections with elevated U concentrations in comparison to sections with background U concentrations. Several criteria were set to characterise UO2-bearing DOM and more than 70 different molecules were found. The vast majority of these UO2-DOM compounds fell in the category of carboxyl-containing aliphatic molecules (H/C between 0.85 and 1.2 and O/C≤0.4) and had a mean value of m/z about 720.
Keywords: Uranium Lake sediments Porewater Disolved organic matter High resolution mass spectrometry
Published in RUNG: 09.10.2019; Views: 3080; Downloads: 0
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49.
50.
The Dark Matter Programme of the Cherenkov Telescope Array
A. Morselli, Christopher Eckner, Gašper Kukec Mezek, Samo Stanič, Serguei Vorobiov, Lili Yang, Gabrijela Zaharijas, Danilo Zavrtanik, Marko Zavrtanik, 2017, published scientific conference contribution

Keywords: dark matter, CTA, gamma rays
Published in RUNG: 16.02.2018; Views: 3127; Downloads: 153
.pdf Full text (769,34 KB)

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