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Liste der bei der PTB angezeigten und geprüften Schusswaffen gemäß § 9 Abs. 2 Nr. 1 Beschussgesetz (BeschG) bis lfd. Nr. 6099
No full textListe der bei der PTB angezeigten und geprüften Schusswaffen gemäß § 9 Abs. 2 Nr. 1 Beschussgesetz (BeschG
Liste der bei der PTB zugelassenen Blockiersysteme für Erbwaffen gemäß § 20 Waffengesetz (WaffG)
No full textListe der bei der PTB zugelassenen Blockiersysteme für Erbwaffen gemäß § 20 Waffengesetz (WaffG
Liste der von der PTB erteilten Baumusterprüfbescheinigungen nach Richtlinie 2006/42/EG
No full textListe der von der PTB erteilten Baumusterprüfbescheinigungen nach Richtlinie 2006/42/E
Liste der bei der PTB zugelassenen Blockiersysteme für Erbwaffen gemäß § 20 Waffengesetz (WaffG)
No full textListe der bei der PTB zugelassenen Blockiersysteme für Erbwaffen gemäß § 20 Waffengesetz (WaffG
Vertreibung und Verfolgung von Angehörigen der Physikalisch-Technischen Reichsanstalt (PTR) im Nationalsozialismus
No full textPTB-Mitteilungen. Band 135 (2025), Heft 1. ISSN 0030-834XVorwort
Jens Simon
Opfer nationalsozialistischer Vertreibung und Verfolgung an der Physikalisch-Technischen Reichsanstalt
Dieter Hoffmann
Eröffnung zum Symposium „Unerwünscht“ am 30. September 2020
Tobias Schäffter
Die Vertreibung von Wissenschaftlerinnen und Wissenschaftlern im Nationalsozialismus
Michael Grüttner
Wie die Wärmeübertragungsforschung nach Amerika kam: Max Jakobs Vertreibung in die USA
Hans-Liudger Dienel
Otto Reichenheim, Günther Wolfsohn und Klaus Schocken – entlassen von der PTR – aus Deutschland vertrieben
Stefan L. Wolff
Die Entlassung des Justiziars Kurt Schweitzer (1886–1973)
Dieter Hoffmann
Eine verworrene Zeit. Familiäre Erinnerungen an Kurt Schweitzer
Angela Schock-Hurs
Methane Sources in Cluj-Napoca, Romania: Insights From Isotopic Analysis
No full textIncreased emissions of methane (CH4) have contributed 0.3–0.8°C to global temperature rise since preindustrial times. Reducing these emissions is crucial to mitigate climate change. Measurements of the isotopic composition of CH4 (δ13C and δ2H) can be used to distinguish various sources of CH4. This study reports continuous measurements of CH4, δ13C and δ2H for 8 months in Cluj‐Napoca, Romania. An automate dextraction and a purification system, coupled to an isotope ratio mass spectrometer alternately measured δ13Cand δ2H of CH4 with 20‐min time resolution at the campus of the Babeş‐Bolyai University. In addition, point source samples were measured to isotopically characterize CH4 sources in the region. The time series show regular CH4 elevations during the night, occasionally superimposed on multiday events. From these elevations, we identified three main CH4 emission categories: Transylvanian biogenic gas (75%); biogenic emissions from rivers and wastewater (38%), predominantly observed during the summer; and a third source emitting 13C‐enriched CH4 in winter, likely of pyrogenic origin (5%). We simulated the CH4 mole fraction at the measurement site using Lagrangian footprints generated from the FLEXPART‐COSMO model convolved with emissions from the TNO‐CoCO2 inventory. The simulations show that the emission inventory is not granular enough to represent the city center. The strong underestimation in winter suggests that the emission inventory did not include the pyrogenic winter source. When the model accurately estimated the CH4 mole fraction, it also predicted the isotopic compositions well
Performance of Cryogenic Adsorbents for Use in Methane Bulk and Clumped Isotope Analysis
No full textRationale
Cryogenic trapping of methane is essential for bulk and clumped isotope analyses, requiring adsorbent materials that enable efficient recovery and preserve isotopic signatures. This study evaluates the performance – capacity, isotopic fractionation, and ease of use – of silica gels, zeolite molecular sieves, and activated carbon under various trapping and desorption conditions. A focus is set on the preservation of methane clumped isotope signatures.
Methods
A well-characterized methane reference gas (40 mL) was cryofocused at 77 K in containers filled with silica gels, zeolite molecular sieves (5A and 13X), or activated carbon alongside non-loaded containers. After loading, the containers were warmed in a water bath (21°C–95°C) for various dwell times. The bulk (D-CH4 and 13C-CH4) and clumped (∆13CH3D and ∆12CH2D2) isotopic composition of the desorbed methane were measured against the untreated reference gas using novel quantum cascade laser absorption spectroscopy (QCLAS).
Results
The best results were achieved with coarse-grained (1–3 mm) silica gels heated to 50°C for at least 5 min or at 21°C–22°C for a minimum of 120 min. Elevated desorption temperatures (80°C–95°C) compromised clumped isotope signatures. Although effective for gas trapping, zeolite molecular sieves, and activated carbon introduced significant bulk and clumped isotopic shifts due to catalytic effects and chromatographic isotopologue separation. Methane cryofocused without adsorbents retained its bulk and clumped isotopic composition without significant fractionation.
Conclusions
Among the tested adsorbents, silica gels demonstrated superior performance, preserving δ13C-CH4, δD-CH4, ∆13CH3D, and ∆12CH2D2 values close to or within performance targets while offering high adsorption capacity, reproducibility, and ease of regeneration. Adsorbent-free cryotrapping is a viable alternative for sufficiently large methane volumes, where vapor pressure isotope effects (VPIEs) become negligible. However, cryogenic adsorbents remain indispensable for ensuring isotopic accuracy for small sample volumes and high-precision applications
D3: Report on the methods for creation of a database of isotopic sources in CH4 for use in atmospheric transport modelling exercises
No full textReport on the methods for creation of a database of isotopic sources in CH4 for use in atmospheric transport modelling exercises
Liste der bei der PTB angezeigten Marken und Herstellerzeichen gemäß § 24 Abs. 6 Waffengesetz (WaffG)
No full textListe der bei der PTB angezeigten Marken und Herstellerzeichen gemäß § 24 Abs. 6 Waffengesetz (WaffG
Liste der bei der PTB zugelassenen Blockiersysteme für Erbwaffen gemäß § 20 Waffengesetz (WaffG)
No full textListe der bei der PTB zugelassenen Blockiersysteme für Erbwaffen gemäß § 20 Waffengesetz (WaffG