Physics of shock waves and high-temperature hydrodynamic phenomena - Ya.B. Zeldovich and Yu.P. Raizer (translated from the Russian and then edited by Wallace D. Hayes and Ronald F. Probstein); Dover Publications, New York, 2002, 944 pp., $34.

The science around the use of masks by the public to impede COVID-19 transmission is advancing rapidly. In this narrative review, we develop an analytical framework to examine mask usage, synthesizing the relevant literature to inform multiple areas: population impact, transmission characteristics, source control, wearer protection, sociological considerations, and implementation considerations. A primary route of transmission of COVID-19 is via respiratory particles, and it is known to be transmissible from presymptomatic, paucisymptomatic, and asymptomatic individuals. Reducing disease spread requires two things: limiting contacts of infected individuals via physical distancing and other measures and reducing the transmission probability per contact. The preponderance of evidence indicates that mask wearing reduces transmissibility per contact by reducing transmission of infected respiratory particles in both laboratory and clinical contexts. Public mask wearing is most effective at reducing spread of the virus when compliance is high. Given the current shortages of medical masks, we recommend the adoption of public cloth mask wearing, as an effective form of source control, in conjunction with existing hygiene, distancing, and contact tracing strategies. Because many respiratory particles become smaller due to evaporation, we recommend increasing focus on a previously overlooked aspect of mask usage: mask wearing by infectious people ("source control") with benefits at the population level, rather than only mask wearing by susceptible people, such as health care workers, with focus on individual outcomes. We recommend that public officials and governments strongly encourage the use of widespread face masks in public, including the use of appropriate regulation.

https://www.pnas.org/content/pnas/118/4/e2014564118.full.pdf

An evidence review of face masks against COVID-19.

/pdf/fire-dynamics-simulator-version-5-user-s-guide-5058kzb0fm.pdf

Fire Dynamics Simulator (Version 5): User's Guide

Certain commercial entities, equipment, or materials may be identified in this document in order to describe an experimental procedure or concept adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the entities, materials, or equipment are necessarily the best available for the purpose. Preface The use of fire models currently extends beyond the fire research laboratories and into the engineering, fire service and legal communities. Surveys [1, 2] of available fire models show a significant increase in number over the last decade. Sufficient evaluation of any model is necessary to ensure that users can judge the adequacy of its technical basis, appropriateness of its use, and confidence level of its predictions. This document provides the theoretical basis for the Fire Dynamics Simulator (FDS) and a summary of the work performed to evaluate the model. This guide is based in part on the " Standard Guide for Evaluating the Predictive Capability of De-terministic Fire Models, " ASTM E 1355 [3]. ASTM E 1355 defines model evaluation as " the process of quantifying the accuracy of chosen results from a model when applied for a specific use. " The model evaluation process consists of two main components: verification and validation. Verification is a process to check the correctness of the solution of the governing equations. Verification does not imply that the governing equations are appropriate; only that the equations are being solved correctly. Validation is a process to determine the appropriateness of the governing equations as a mathematical model of the physical phenomena of interest. Typically, validation involves comparing model results with experimental measurement. Differences that cannot be explained in terms of numerical errors in the model or uncertainty in the measurements are attributed to the assumptions and simplifications of the physical model. Evaluation is critical to establishing both the acceptable uses and limitations of a model. Throughout its development, FDS has undergone various forms of evaluation, both at NIST and beyond. This guide provides a survey of work conducted to date to evaluate FDS. Roughly half of the referenced studies were aimed primarily at model evaluation, the other half describe limited work to validate FDS for a specific use. The latter group were performed mostly by practicing engineers who did not have the time or resources to comprehensively evaluate the model. Collectively, the body …

/pdf/fire-dynamics-simulator-version-3-technical-reference-guide-47qshgton4.pdf

Fire dynamics simulator (Version 3) - Technical reference guide

The COVID-19 pandemic has revealed critical knowledge gaps in our understanding of and a need to update the traditional view of transmission pathways for respiratory viruses. The long-standing definitions of droplet and airborne transmission do not account for the mechanisms by which virus-laden respiratory droplets and aerosols travel through the air and lead to infection. In this Review, we discuss current evidence regarding the transmission of respiratory viruses by aerosols-how they are generated, transported, and deposited, as well as the factors affecting the relative contributions of droplet-spray deposition versus aerosol inhalation as modes of transmission. Improved understanding of aerosol transmission brought about by studies of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection requires a reevaluation of the major transmission pathways for other respiratory viruses, which will allow better-informed controls to reduce airborne transmission.

Airborne transmission of respiratory viruses.

/pdf/fire-dynamics-simulator-version-2-technical-reference-guide-4aqxgmeqay.pdf

Fire Dynamics Simulator (Version 2) -- Technical Reference Guide | NIST

/pdf/fire-dynamics-simulator-technical-reference-guide-volume-1-15a6kbrhbq.pdf

Simo Hostikka

Papers

Fire Dynamics Simulator (Version 5): User's Guide

Fire dynamics simulator (Version 3) - Technical reference guide

Fire Dynamics Simulator (Version 2) -- Technical Reference Guide | NIST

Fire dynamics simulator technical reference guide volume 1 :: mathematical model

Modelling aerosol transport and virus exposure with numerical simulations in relation to SARS-CoV-2 transmission by inhalation indoors