Editorial

The five papers in this issue of the Weizenbaum Journal of the Digital Society examine processes of digitalization from a perspective that encompasses political economy, political science, psychology, and communication science. In turn, the contributors explore the relationship between digitalization and capitalism, the role of civic tech initiatives, the regulation of political micro-targeting on social media, the use of fictive accounts of historical figures on social media, and concepts for the participatory development of research agendas

Editorial

Joseph Weizenbaum would have been 100 years old on January 8, 2023. This anniversary was a welcome occasion to remember the life, work, and impact of the great computer scientist and public intellectual at the Weizenbaum Institute.  This special issue compiles a series of articles directly or indirectly related to his work. Contributions center on Weizenbaum as an individual and his public role as a progressive intellectual, encompassing contemporary viewpoints on ethics in digital technology

Spectroscopy of single- and double-wall carbon nanotubes in different environments

Individual single-wall carbon nanotubes (SWNTs) and double-wall carbon nanotubes (DWNTs) are suspended in water using sodium-cholate and other surfactants. The absorption and luminescence spectra of the resulting suspensions exhibit features originating from small- and large-diameter tubes. Photoluminescence excitation spectra show emission features over a wide wavelength range from all tube types spectroscopically accessible. Time-resolved photoluminescence (PL) spectra from small diameter tubes are dominated by non-radiative decay which is found to vary significantly with tube chirality and diameter as well as with changes of the environment. The studies provide evidence for PL from small diameter core tubes in DWNTs and for a correlation of PL decay times with exciton red-shift brought about by interaction with the environment

Assessment of current methane emission quantification techniques for natural gas midstream applications

International audienceAbstract. Methane emissions from natural gas systems are increasingly scrutinized, and accurate reporting requires quantification of site- and source-level measurement. We evaluate the performance of 10 available state-of-the-art CH4 emission quantification approaches against a blind controlled-release experiment at an inerted natural gas compressor station in 2021. The experiment consisted of 17 blind 2 h releases at a single exhaust point or multiple simultaneous ones. The controlled releases covered a range of methane flow rates from 0.01 to 50 kg h−1. Measurement platforms included aircraft, drones, trucks, vans, ground-based stations, and handheld systems. Herewith, we compare their respective strengths, weaknesses, and potential complementarity depending on the emission rates and atmospheric conditions. Most systems were able to quantify the releases within an order of magnitude. The level of errors from the different systems was not significantly influenced by release rates larger than 0.1 kg h−1, with much poorer results for the 0.01 kg h−1 release. It was found that handheld optical gas imaging (OGI) cameras underestimated the emissions. In contrast, the “site-level” systems, relying on atmospheric dispersion, tended to overestimate the emission rates. We assess the dependence of emission quantification performance on key parameters such as wind speed, deployment constraints, and measurement duration. At the low wind speeds encountered (below 2 m s−1), the experiments did not reveal a significant dependence on wind speed. The ability to quantify individual sources degraded during multiple-source releases. Compliance with the Oil and Gas Methane Partnership's (OGMP 2.0) highest level of reporting may require a combination of the specific advantages of each measurement technique and will depend on reconciliation approaches. Self-reported uncertainties were either not available or were based on the standard deviation in a series of independent realizations or fixed values from expert judgment or theoretical considerations. For most systems, the overall relative errors estimated in this study are higher than self-reported uncertainties

Toward the Standardization of Biochar Analysis: The COST Action TD1107 Interlaboratory Comparison

Biochar produced by pyrolysis of organic residues is increasingly used for soil amendment and many other applications. However, analytical methods for its physical and chemical characterization are yet far from being specifically adapted, optimized, and standardized. Therefore, COST Action TD1107 conducted an interlaboratory comparison in which 22 laboratories from 12 countries analyzed three different types of biochar for 38 physical–chemical parameters (macro- and microelements, heavy metals, polycyclic aromatic hydrocarbons, pH, electrical conductivity, and specific surface area) with their preferential methods. The data were evaluated in detail using professional interlaboratory testing software. Whereas intralaboratory repeatability was generally good or at least acceptable, interlaboratory reproducibility was mostly not (20% < mean reproducibility standard deviation < 460%). This paper contributes to better comparability of biochar data published already and provides recommendations to improve and harmonize specific methods for biochar analysis in the future.ISSN:0021-8561ISSN:1520-511