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After a halt of four years, the n TOF spallation neutron facility at CERN has resumed operation in November 2008 with a new spallation target characterized by an improved safety and engineering design, resulting in a more robust overall performance and e cient cooling. The rst measurement during the 2009 run has aimed at the full characterization of the neutron beam. Several detectors, such as calibrated ssion chambers, the n TOF Silicon Monitor, a Mi- croMegas detector with 10B and 235U samples, as well as liquid and solid scintillators have been used in order to characterize the properties of the neutron uence. The spatial pro le of the beam has been studied with a specially designed \X-Y

AbstractImproving the long-term stability of perovskite solar cells is critical to the deployment of this technology. Despite the great emphasis laid on stability-related investigations, publications lack consistency in experimental procedures and parameters reported. It is therefore challenging to reproduce and compare results and thereby develop a deep understanding of degradation mechanisms. Here, we report a consensus between researchers in the field on procedures for testing perovskite solar cell stability, which are based on the International Summit on Organic Photovoltaic Stability (ISOS) protocols. We propose additional procedures to account for properties specific to PSCs such as ion redistribution under electric fields, reversible degradation and to distinguish ambient-induced degradation from other stress factors. These protocols are not intended as a replacement of the existing qualification standards, but rather they aim to unify the stability assessment and to understand failure modes. Finally, we identify key procedural information which we suggest reporting in publications to improve reproducibility and enable large data set analysis.

Abstract A recent article in this journal claimed to assess the socio-technical potential for onshore wind energy in Europe. We find the article to be severely flawed and raise concerns in five general areas. Firstly, the term socio-technical is not precisely defined, and is used by the authors to refer to a potential that others term as merely technical. Secondly, the study fails to account for over a decade of research in wind energy resource assessments. Thirdly, there are multiple issues with the use of input data and, because the study is opaque about many details, the effect of these errors cannot be reproduced. Fourthly, the method assumes a very high wind turbine capacity density of 10.73 MW/km2 across 40% of the land area in Europe with a generic 30% capacity factor. Fifthly, the authors find an implausibly high onshore wind potential, with 120% more capacity and 70% more generation than the highest results given elsewhere in the literature. Overall, we conclude that new research at higher spatial resolutions can make a valuable contribution to wind resource potential assessments. However, due to the missing literature review, the lack of transparency and the overly simplistic methodology, Enevoldsen et al. (2019) potentially mislead fellow scientists, policy makers and the general public.

A study of the production of prompt J/ψ mesons contained in jets in proton-proton collisions at s=8TeV is presented. The analysis is based on data corresponding to an integrated luminosity of 19.1 fb−1 collected with the CMS detector at the LHC. For events with at least one observed jet, the angular separation between the J/ψ meson and the jet is used to test whether the J/ψ meson is part of the jet. The analysis shows that most prompt J/ψ mesons having energy above 15 GeV and rapidity |y|<1 are contained in jets with pseudorapidity |ηjet|<1. The differential distributions of the probability to have a J/ψ meson contained in a jet as a function of jet energy for a fixed J/ψ energy fraction are compared to a theoretical model using the fragmenting jet function approach. The data agree best with fragmenting jet function calculations that use a long-distance matrix element parameter set in which prompt J/ψ mesons are predicted to be unpolarized. This technique demonstrates a new way to test predictions for prompt J/ψ production using nonrelativistic quantum chromodynamics. Physics Letters B, 804 ISSN:0370-2693 ISSN:0031-9163 ISSN:1873-2445