scholarly journals Improved estimates of 222 nm far-UVC susceptibility for aerosolized human coronavirus via a validated high-fidelity coupled radiation-CFD code

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrew G. Buchan ◽  
Liang Yang ◽  
David Welch ◽  
David J. Brenner ◽  
Kirk D. Atkinson
Keyword(s):  
Experimental Studies ◽  
Indoor Environments ◽  
Viral Inactivation ◽  
Survival Fraction ◽  
Serious Infection ◽  
Rapid Spread ◽  
Multiphysics Modelling ◽  
Air Disinfection ◽  
Human Coronaviruses ◽  
Modelling Approach

AbstractTransmission of SARS-CoV-2 by aerosols has played a significant role in the rapid spread of COVID-19 across the globe. Indoor environments with inadequate ventilation pose a serious infection risk. Whilst vaccines suppress transmission, they are not 100% effective and the risk from variants and new viruses always remains. Consequently, many efforts have focused on ways to disinfect air. One such method involves use of minimally hazardous 222 nm far-UVC light. Whilst a small number of controlled experimental studies have been conducted, determining the efficacy of this approach is difficult because chamber or room geometry, and the air flow within them, influences both far-UVC illumination and aerosol dwell times. Fortunately, computational multiphysics modelling allows the inadequacy of dose-averaged assessment of viral inactivation to be overcome in these complex situations. This article presents the first validation of the WYVERN radiation-CFD code for far-UVC air-disinfection against survival fraction measurements, and the first measurement-informed modelling approach to estimating far-UVC susceptibility of viruses in air. As well as demonstrating the reliability of the code, at circa 70% higher, our findings indicate that aerosolized human coronaviruses are significantly more susceptible to far-UVC than previously thought.

scholarly journals An Overview of SARS-CoV-2 and Animal Infection

2020 ◽  
Vol 7 ◽  
Author(s):  
Mohamed A. A. Mahdy ◽  
Waleed Younis ◽  
Zamzam Ewaida
Keyword(s):  
Intermediate Host ◽  
Animal Species ◽  
Experimental Studies ◽  
Short Review ◽  
World Health ◽  
Wholesale Market ◽  
Animal Infection ◽  
Rapid Spread ◽  
Novel Coronavirus ◽  
Health Organization

A novel coronavirus has been reported as the causative pathogen of the Coronavirus disease 2019 (COVID-19) outbreak in Wuhan city, China in December 2019. Due to the rapid spread of the virus worldwide, it has been announced as a pandemic by the World Health Organization (WHO). Hospitalized patients in Wuhan were associated with the Huanan seafood wholesale market where live animals, such as poultry, bats, snakes, frogs, rabbits, marmots, and hedgehogs are sold in that market which suggests a possible zoonotic infection. It was suggested that bat is the natural host of SARS-CoV-2, but the intermediate host is still unclear. It is essential to identify the potential intermediate host to interrupt the transmission chain of the virus. Pangolin is a highly suspected candidate as an intermediate host for SARS-CoV-2. Recently, SARS-CoV-2 infection has been reported in cats, dogs, tigers, and lions. More recently SARS-CoV-2 infection affected minks severely and zoonotic transfer with a variant SARS-CoV-2 strain evidenced in Denmark, Netherlands, USA, and Spain suggesting animal-to-human and animal-to-animal transmission within mink farms. Furthermore, experimental studies documented the susceptibility of different animal species to SARS-CoV-2, such as mice, golden hamsters, cats, ferrets, non-human primates, and treeshrews. It is also essential to know the possibility of infection for other animal species. This short review aims to provide an overview on the relation between severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection and animals.

scholarly journals Analysis of a Lab-Scale Heat Transformation Demonstrator Based on a Gas–Solid Reaction

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2234 ◽  
Author(s):  
Jana Stengler ◽  
Julius Weiss ◽  
Marc Linder
Keyword(s):  
Experimental Studies ◽  
Hydration Reaction ◽  
Solid Reaction ◽  
Discharge Performance ◽  
Different Temperatures ◽  
Higher Temperature ◽  
Solid Bulk ◽  
Heat Transformation ◽  
Modelling Approach ◽  
Gas Solid Reaction

Heat transformation based on reversible chemical reactions has gained significant interest due to the high achievable output temperatures. This specific type of chemical heat pump uses a reversible gas–solid reaction, with the back and forward reactions taking place at different temperatures: by running the exothermic discharge reaction at a higher temperature than the endothermic charge reaction, the released heat is thermally upgraded. In this work, we report on the experimental investigation of the hydration reaction of strontium bromide (SrBr2) with regard to its use for heat transformation in the temperature range from 180 °C to 250 °C on a 1 kg scale. The reaction temperature is set by adjusting the pressure of the gaseous reactant. In previous experimental studies, we found the macroscopic and microscopic properties of the solid bulk phase to be subject to considerable changes due to the chemical reaction-. In order to better understand how this affects the thermal discharge performance of a thermochemical reactor, we combine our experimental work with a modelling approach. From the results of the presented studies, we derive design rules and operating parameters for a thermochemical storage module based on SrBr2.

scholarly journals Reactive Transport and Its Implications on Heavy Oil HTGC Analysis. A Coupled Thermo-Hydro-Chemical (THC) Multiphysics Modelling Approach

2021 ◽  
Author(s):  
Diana Margarita Hernandez-Baez ◽  
Alastair Reid ◽  
Antonin Chapoy ◽  
Bahman Tohidi ◽  
Roda Bounaceur ◽  
...  
Keyword(s):  
Flow Rate ◽  
Heavy Oil ◽  
Reactive Transport ◽  
High Efficiency ◽  
Thermal Cracking ◽  
Low Flow ◽  
Oil Hydrocarbons ◽  
Multiphysics Modelling ◽  
Physics Model ◽  
Modelling Approach

This chapter provides an insight into the reactive transport in a capillary column which heavy-oil hydrocarbons undergo when analysed by high temperature gas chromatography (HTGC), and their implications on characterisation outcomes, namely thermal cracking of the injected sample; and incomplete or non-elution of heavy components from the column, by using a coupled Thermo-Hydro-Chemical (THC) multiphysics modelling approach. For this purpose, a computational coupled THC, multicomponent, multi-physics model is developed, accounting for: multiphase equilibrium using an in-house, extended thermodynamics distribution factors dataset, up to nC98H198; transport and fluid flow in COMSOL and MATLAB; and chemical reactions using kinetics and mechanisms of the thermal cracking, in CHEMKIN. The determination of the former extended dataset is presented using two complementary HTGC modes: i) High-Efficiency mode, with a long column operated at low flow rate; and ii) true SimDist mode, with a short column operated at high flow rate and elution up to nC100H202.

scholarly journals Multiphysics analysis for the determination of valvetrain characteristics

2005 ◽  
Vol 219 (9) ◽  
pp. 1109-1117 ◽  
Author(s):  
M Teodorescu ◽  
V Votsios ◽  
H Rahnejat
Keyword(s):  
Combustion Process ◽  
Linear Dynamics ◽  
Non Linear ◽  
Multiphysics Modelling ◽  
Opening And Closing ◽  
Exhaust Valves ◽  
Modelling Approach ◽  
The Ideal

The ideal function of a valvetrain system is to synchronize the opening and closing of the inlet and exhaust valves with the required thermodynamics of the combustion process. As such, ideally a kinematic-type mechanism is desired. However, the timing requirements in the action of each valve and between any inlet-exhaust pair necessitate the use of contacting pairs of suitable profiles. The very existence of contact renders the problem one of complex non-linear dynamics, which is further exacerbated by the translational imbalance of the reciprocating compliant elements such as the valve itself. The interplay between these various forms of dynamics, inertial, structural, and impact/contact, make the problem quite complex to analyse. As a result, some of the most important problems with valvetrains are only surmised at, rather than fundamentally understood. The multiphysics modelling approach proposed in this paper renders a better understanding, as well as conforming to experimental observations.

scholarly journals Portable HEPA Purifiers to Eliminate Airborne SARS-CoV-2: A Systematic Review

2021 ◽  
pp. 019459982110226
Author(s):  
David T. Liu ◽  
Katie M. Philips ◽  
Marlene M. Speth ◽  
Gerold Besser ◽  
Christian A. Mueller ◽  
...  
Keyword(s):  
English Language ◽  
High Efficiency ◽  
Experimental Studies ◽  
Mitigation Strategies ◽  
Data Sources ◽  
Submicron Particles ◽  
World Health ◽  
Indoor Environments ◽  
Or Efficiency ◽  
Current State

Objective Current epidemiologic predictions of COVID-19 suggest that SARS-CoV-2 mitigation strategies must be implemented long-term. In-office aerosol-generating procedures pose a risk to staff and patients while necessitating examination room shutdown to allow aerosol decontamination by indwelling ventilation. This review summarizes the current state of knowledge on portable high-efficiency particulate air (HEPA) purifiers’ effectiveness in eliminating airborne SARS-CoV-2 from indoor environments. Data Sources Medline, Embase, Cochrane Databases, and the World Health Organization’s COVID-19 Global Literature on Coronavirus Disease. Review Methods Data sources were systematically searched for original English-language published studies indexed up to January 14, 2021 per the following search strategy: (“HEPA” OR “High-efficiency” OR “High-efficiency particulate air” OR “Efficiency particulate” OR “Purifier” OR “Filter” OR “Cleaner” OR “Filtration”) AND (“COVID” OR “COVID-19” OR “SARS-CoV-2” OR “Coronavirus”). Additional relevant studies were identified by searching the reference lists of included articles. Results Eleven published studies have evaluated the effectiveness of portable HEPA purifiers in eliminating airborne SARS-CoV-2 with relevantly sized surrogate particles. Ten studies evaluated aerosols and submicron particles similar in size to SARS-CoV-2 virions. In all studies, portable HEPA purifiers were able to significantly reduce airborne SARS-CoV-2-surrogate particles. The addition of portable HEPA purifiers augmented other decontamination strategies such as ventilation. Conclusion Experimental studies provide evidence for portable HEPA purifiers’ potential to eliminate airborne SARS-CoV-2 and augment primary decontamination strategies such as ventilation. Based on filtration rates, additional air exchanges provided by portable HEPA purifiers may be calculated and room shutdown times potentially reduced after aerosol-generating procedures.

DESIGN OF ELECTRIC AIR OZONATOR FOR LIVESTOCK KEEPING HOUSES

2021 ◽  
pp. 74-79
Author(s):  
ALEKSANDR N. MANUYLENKO ◽  
◽  
SERGEY V. VENDIN ◽  
Keyword(s):  
Critical Concentration ◽  
Rapid Development ◽  
Experimental Studies ◽  
Control Unit ◽  
Animal Husbandry ◽  
Feed Consumption ◽  
Dust Particles ◽  
Tungsten Electrodes ◽  
Air Disinfection ◽  
Reliability Of Operation

One of the most important tasks of animal husbandry is establishing and maintaining normalized microclimate parameters in closed livestock keeping houses: temperature, humidity, speed of air fl ows, illumination, gas composition of air, and suspended dust particles. Failure to comply with established zootechnical and veterinary-sanitary standards in a closed room, (other things being equal) can lead to a decrease in productivity, increased feed consumption per unit of production, the rapid development of pathogenic microbes, and the spread of infections. The design of an electric air ozonizer based on a corona discharge and an air ozonization system is proposed to ensure high-quality air disinfection in livestock keeping houses in accordance with sanitary standards. A distinctive novelty of the proposed design is the emitter module, made as a ceramic base, on which tungsten electrodes are fi xed in the form of a grid with a honeycomb cell. The advantages of the proposed design of an electric air ozonizer include the reliability of operation due to shutdown in case of an emergency, protection against overheating and critical concentration of ozone inside the room in one place due to a weather vane, ozone and temperature sensors, and a central control unit. The proposed design of the electric ozonation system will increase the effi ciency of disinfection and disinsection of air in industrial livestock buildings, and will also ensure a more uniform concentration of ozone throughout the room volume due to the location of ozonizers and their improved operation of the emitter in terms of performance and uniformity. Preliminary evaluative experimental studies to test the performance of the proposed electric air ozonator in a livestock keeping house with an area of 1600 m2 have shown that its design reduces the amount of microfl ora in the air from 27520 to 240 colonies/m3, while increasing ozone concentration to 0.035 mg/m3, as well as reduces the content of harmful gas impurities of hydrogen sulfi de from 0.16 to 0.0003 mg/l; ammonia – from 0.13 to 0.05 mg / l; carbon dioxide – from 10 to 0.2 mg/l.

scholarly journals Effectiveness of germicidal ultraviolet light to inactivate coronaviruses on personal protective equipment to reduce nosocomial transmission

2021 ◽  
pp. 1-6
Author(s):  
Carolina Camargo ◽  
Andréanne Lupien ◽  
Fiona McIntosh ◽  
Dick Menzies ◽  
Marcel A. Behr ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Personal Protective Equipment ◽  
Plaque Assay ◽  
Protective Equipment ◽  
Viral Inactivation ◽  
Infectious Dose ◽  
Polymerase Chain ◽  
Human Coronaviruses ◽  
N95 Respirators ◽  
Tissue Culture Infectious Dose

Abstract Objective: To circumvent the need for rationing personal protective equipment (PPE), we explored whether germicidal ultraviolet light (GUV) could be used to inactivate human coronaviruses on PPE, enabling safe reuse. Design: We performed a laboratory study to assess the ability of 2 commercially available portable GUV devices to inactivate 2 common cold coronaviruses (HCoV-229E and HCoV-OC43) and severe acute respiratory syndrome coronavirus virus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), on the surface of whole N95 respirators and coupons cut from those respirators. We experimentally contaminated N95 respirators with coronavirus cultures and then assessed viral inactivation after GUV exposure by plaque assay, the median tissue culture infectious dose (TCID50) assay, and quantitative reverse-transcriptase polymerase chain reaction (RT-PCR). Results: We found that GUV could efficiently inactivate coronaviruses on the surface of N95 masks, with an average reduction in viral titers of 5-log for HCoV-229E, 3-log for HCoV-OC43, and 5-log for SARS-CoV-2. In addition, the GUV susceptibility of HCoV-229E was similar on coupons and whole N95 respirators. Conclusions: We demonstrate that diverse human coronaviruses, including SARS-CoV-2, are susceptible to GUV inactivation, and 2 scalable portable GUV devices were effective in inactivating coronaviruses on N95 respirators. Thus, GUV treatment with commercially scalable devices may be an effective method to decontaminate PPE, allowing their safe reuse.

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