Large-scale volumetric flow studies on transport of aerosol particles using a breathing human model with and without face protections

Exhalation of small aerosol particle droplets and their airborne transport, dispersion, and (local) accumulation in closed rooms have been identified as the main pathways for direct and indirect respiratory virus transmission from person to person, for example, for severe acute respiratory syndrome coronavirus-2 or measles. Therefore, understanding airborne transport mechanisms of aerosol particles inside closed populated rooms is an important key factor for assessing and optimizing various mitigation strategies. Unsteady flow features, which are typically evolving in such mixed convection flow scenarios, govern the respective particle transport properties. Experimental and numerical methods that enable capturing the related broad range of scales in such internal flows over many cubic meters in order to provide reliable data for the adaptation of proper mitigation measures (distances, masks, shields, air purifiers, ventilation systems, etc.) are required. In the present work, we show results of a large-scale, three-dimensional Lagrangian particle tracking (LPT) experiment, which has been performed in a 12-m3 generic test room capturing up to 3 × 106 long-lived and nearly neutrally buoyant helium-filled soap bubbles (HFSBs) with a mean diameter of dHFSB ∼370 μm as (almost) passive tracers. HFSBs are used as fluid mechanical replacements for small aerosol particles dP < 5 μm, which allow to resolve the Lagrangian transport properties and related unsteady flow field inside the whole room around a cyclically breathing thermal manikin with and without mouth-nose-masks and shields applied. Six high-resolution complementary metal-oxide semiconductor streaming cameras, a large array of powerful pulsed light emitting diodes, and the variable-time step Shake-The-Box LPT algorithm have been applied in this experimental study of internal flows in order to gain insight into the complex transient and turbulent aerosol particle transport and dispersion processes around a seated and breathing human model. © 2022 Author(s).

Identification of Unmasked Faces: Protection in Public Places from COVID-19 and Other Infections

The 3rd wave of Coronavirus is hitting the world. The doctors and scientists are also in their last phase of developing a vaccine. But it is challenging to get the vaccine for everyone due to several factors such as production, supply chain, cold chain and price. Till then, the only way to prevent infection is to wear a mark and follow social distancing. This paper describes how to identify mask and no-mask faces in public areas using image processing algorithms. One of the significant steps taken by people around the world to stay safe is wearing masks. This research-based project gets a camera-based solution to detect faces and recognize them if they exist in the database. If the live stream has unmasked faces, which aren't present in the existing database, give out an alarm to alert the administrator or user. It is a significant project for times like these because now, with the lockdown ending in the world because of financial meltdowns, most public places like malls, temples, shops, grocery stores, and medical stores are opening. A concern for the safety and well-being of everyone around us because the virus can spread at a logarithmic rate and cause mass damage in the form of large bills and some cases, death. To avoid this, we always have to wear masks when in public places, and this is what the project does. The crucial technologies used in our manuscript are Face Detection, Face Recognition Identification, and Feature Detection in the face. © 2021 IEEE.

The Conjunction of Deterministic and Probabilistic Events in Realistic Scenarios of Outdoor Infections

The aim of this paper is the derivation of an robust formalism that calculates the so-called social distancing as already determined in the ongoing Corona Virus Disease 2019 (Covid-19 in short) being established in various places in the world between 1.5 m and 2.5 m. This would constitutes a critic space of separation among people in the which aerosols might not be effective to infect healthy people. In addition to wearing masks and face protection, the social distancing appears to be critic to keep people far of infections and consequences produced from it. In this way, the paper has opted by the incorporation of a full deterministic model inside the equation of Weiss, by the which it fits well to the action of outdoor infection when wind manages the direction and displacement of aerosols in space. Thus, while a deterministic approach targets to propose a risk’s probability, a probabilistic scenario established by Weiss in conjunction to the deterministic events would yield an approximated model of outdoor infection when there is a continuous source of infected aerosols that are moving through air in according to a wind velocity. The simulations have shown that the present approach is valid to some extent in the sense that only the 1D case is considered. The model can be extended with the implementation of physical variables that can attenuate the presence of disturbs and random noise that minimizes the effectiveness of present proposal. © 2021, ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering.

[Head and Face Protection of the Health Care Workers in the Operating Room of Peking Union Medical College Hospital during the Corona Virus Disease-19 Pandemic].

Objective To investigate the understanding of the head and face protection of the health care workers in operating room of Peking Union Medical College Hospital during the corona virus disease-19(COVID-19) pandemic.Methods The knowledge of head and face protection of health care workers in the operating room was evaluated based on the non-registered questionnaires for protection measures collected on-line.Results The survey was conducted in two phases.In the first phase(COVID-19 outbreak),153 questionnaires were collected.In the second phase(when Beijing lowered the emergency response to level 3 and normalized the epidemic prevention and control),101 questionnaires were collected.The results showed that 98% of health care workers had used any form of protective devices during the pandemic and anesthesiologists had the highest usage rate(93.0%)of ear-loop face mask with eye shield.During the pandemic,health care workers mainly used goggles(71.2%)for protection to diagnose and treat the patients with fever and ear-loop face mask with eye shield(56.2%)for protection to diagnose and treat the non-fever patients.In the first-and second-phase survey,43% and 68% of health care workers still used protection,and they mainly used face shield(50.0% and 56.5%)and ear-loop face mask with eye shield(56.1% and 68.1%).Conclusions During the pandemic,more than 90% of the health care workers in the operating room of Peking Union Medical College Hospital were aware of head and face protection.Different healthcare workers in the operating room had different choices of head and face protection,and more than 40% of them would still keep such protection during the normalized stage of pandemic prevention and control.