ABSTRACT
During the recent pandemic of SARS-CoV-2, and as a reaction to the worldwide shortage of surgical masks, several countries have introduced new types of masks named “community face coverings” (CoFC). To ensure the quality of such devices and their relevance to slow down the virus spreading, a quick reaction of the certification organisms was necessary to fix the minimal acceptable performances requirements. Moreover, many laboratories involved in the aerosol research field have been asked to perform tests in a quick time according to (CEN, 2020) proposed by the European committee for standardization. This specification imposes a minimal air permeability of 96 L m–2 s–1 for a 100 Pa pressure drop and a minimal filtration efficiency of 70% for 3 µm diameter particles. In the present article, an intercomparison of efficiencies and permeabilities measured by 3 laboratories has been performed. Results are in good agreement considering the heterogeneity of the material samples (within 27% in terms of filtration efficiency and less than 20% in terms of permeability). On this basis, an analysis of 233 materials made of woven, non-woven and mixed fibrous material has been done in terms of filtration efficiency and air permeability. For some of them, measurements have been performed for 0.2 µm, 1 µm and 3 µm particle diameters. As expected, no deterministic correlation could be determined to link these efficiencies to the permeability of the considered samples. However, a trend could be identified for woven and mixed materials with an increase of filtration efficiency when the air permeability decreases. The same exercise has been conducted to link the filtration efficiency measured at 3 µm to the one for lower diameters. Finally, a discussion on the kind of material that is the most relevant to manufacture CoFC supported by spectral filtration efficiency values (from 0.02 µm to 3 µm) is proposed. Copyright: The Author's institution. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.
ABSTRACT
We present the VECMA toolkit (VECMAtk), a flexible software environment for single and multiscale simulations that introduces directly applicable and reusable procedures for verification, validation (V&V), sensitivity analysis (SA) and uncertainty quantication (UQ). It enables users to verify key aspects of their applications, systematically compare and validate the simulation outputs against observational or benchmark data, and run simulations conveniently on any platform from the desktop to current multi-petascale computers. In this sequel to our paper on VECMAtk which we presented last year [1] we focus on a range of functional and performance improvements that we have introduced, cover newly introduced components, and applications examples from seven different domains such as conflict modelling and environmental sciences. We also present several implemented patterns for UQ/SA and V&V, and guide the reader through one example concerning COVID-19 modelling in detail. This article is part of the theme issue 'Reliability and reproducibility in computational science: implementing verification, validation and uncertainty quantification in silico'.