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

Ville Vuorinen, Mia Aarnio, Mikko Alava, Ville Alopaeus, Nina Atanasova, Mikko Auvinen, Nallannan Balasubramanian, Hadi Bordbar, Panu Erästö, Rafael Grande, Nick Hayward, Antti Hellsten (+18 others)
2020 Safety Science  
The introduced concept, 'exposure time' to virus containing aerosols is proposed to complement the traditional 'safety distance' thinking.  ...  We provide research findings on the physics of aerosol and droplet dispersion relevant to the hypothesized aerosol transmission of SARS-CoV-2 during the current pandemic.  ...  better understand transmission of SARS-CoV-2 in public places under various circumstances. (6) Quantitative decision making metrics, to assess safety of public premises, are needed.  ... 
doi:10.1016/j.ssci.2020.104866 pmid:32834511 pmcid:PMC7428778 fatcat:hvagmqlm7zf3nfqpwto4bjkvpa

Field Simulation of Aerosol Transmission of SARS-CoV-2 in a Special Building Layout — Guangdong Province, China, 2021

Zhuona Zhang, National Institute of Environmental Health, China Center for Disease Control and Prevention, Beijing, China, Xia Li, Qin Wang, Jin Xu, Qinqin Jiang, Sili Jiang, Jiayun Lyu, Shiqiang Liu, Ling Ye, Jun Yuan, Wenru Feng (+4 others)
2021 China CDC Weekly  
Aerosol transmission was one route for the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and usually occurred in confined spaces.  ...  Centralized isolation and home isolation in handshake buildings creates a risk of SARS-CoV-2 aerosol transmission under certain conditions.  ...  Presently, the research on SARS-CoV-2 transmission usually focused on the simulation cabin experiment or computational fluid dynamic model (9) (10) .  ... 
doi:10.46234/ccdcw2021.176 pmid:34594974 pmcid:PMC8392788 fatcat:7rzo56qtofa67m7inyxwzatwre

Comparison of Safety Distances Based on the Electromagnetic Field and Based on the SAR for Occupational Exposure of a 900-MHz Base Station Antenna

W. Joseph, L. Martens
2005 IEEE transactions on electromagnetic compatibility (Print)  
This means that from 10 W and up the SAR does not need to be determined to obtain the largest safety distances.  ...  Up to about 10 W the localized SAR delivers the largest safety distances when the electric field averaged in a volume is considered.  ...  Comparison of Simulated and Measured Safety Distances We multiply again the simulated and measured localized SAR with a correction factor 3 [6] instead of 2 proposed by CENELEC [2] .  ... 
doi:10.1109/temc.2005.854100 fatcat:o43t2dy4uvfmphoft25g775tji

Parallel transmission RF pulse design with strict temperature constraints

Cem M. Deniz, Giuseppe Carluccio, Christopher Collins
2017 NMR in Biomedicine  
RF safety in parallel transmission (pTx) is generally ensured by imposing specific absorption rate (SAR) limits during pTx radiofrequency (RF) pulse design.  ...  Parallel transmission RF pulses were designed using either SAR or temperature constraints and compared to each other and unconstrained RF pulse design in terms of excitation fidelity and safety.  ...  SAR-based safety control of multichannel transmit systems during RF pulse design has been made tractable by using Virtual Observation Points (VOPs) 15 in electromagnetic (EM) field simulations for reducing  ... 
doi:10.1002/nbm.3694 pmid:28187249 pmcid:PMC5456413 fatcat:jv3aclznardpxeav3vx545tba4

A deep learning method for image‐based subject‐specific local SAR assessment

E.F. Meliadò, A.J.E Raaijmakers, A. Sbrizzi, B.R. Steensma, M. Maspero, M.H.F. Savenije, P.R. Luijten, C.A.T. Berg
2019 Magnetic Resonance in Medicine  
Local specific absorption rate (SAR) cannot be measured and is usually evaluated by offline numerical simulations using generic body models that of course will differ from the patient's anatomy.  ...  An additional safety margin is needed to include this intersubject variability. In this work, we present a deep learning-based method for image-based subject-specific local SAR assessment.  ...  Although simulations on 1 model have been used previously as a safety analysis, 17, 18, 41 currently it is more common to use at least multiple models and predict peak local SAR by the maximum SAR over  ... 
doi:10.1002/mrm.27948 pmid:31483521 pmcid:PMC6899474 fatcat:5rqtu2zbxfdyzhtndhumbu6mzu

Safety Evaluation of a New Setup for Transcranial Electric Stimulation during Magnetic Resonance Imaging

Fróði Gregersen, Cihan Göksu, Gregor Schaefers, Rong Xue, Axel Thielscher, Lars G. Hanson
2021 Brain Stimulation  
Subsequently, specific absorption rate (SAR) simulations for realistic lead configurations with low-conductivity leads and two electrode types were performed at 128 MHz and 298 MHz being the Larmor frequencies  ...  Realistic lead configurations increased the head SAR and the local head SAR at the electrodes only minimally.  ...  For our setup, the simulations showed no increase in head SAR and head local SAR for both field strengths. Additionally, no temperature above the safety limits was recorded.  ... 
doi:10.1016/j.brs.2021.02.019 pmid:33706007 fatcat:j6fukd2h4zgydphickv6dmmxhy

Radio-Frequency Safety Assessment of Stents in Blood Vessels During Magnetic Resonance Imaging

Kyoko Fujimoto, Leonardo M Angelone, Elena Lucano, Sunder S Rajan, Maria Ida Iacono
2018 Frontiers in Physiology  
Furthermore, Etan results showed that volume-averaged SAR values might not be sufficient to assess RF safety.  ...  Methods: A numerical model of an RF birdcage body coil and an anatomically realistic virtual patient with a native spatial resolution of 1 mm3 were used to simulate the in vivo electric field at 64 MHz  ...  SAR exposed = 10 W/kg − 8 W/kg × exposed mass of AustinMan whole body mass of AustinMan In this study, the whole-body SAR of 2 W/kg was the limiting safety condition for all the simulations except for  ... 
doi:10.3389/fphys.2018.01439 pmid:30459628 pmcid:PMC6232906 fatcat:zdzel2emdvcwnpbmb3durqyuaa

Analysis of SAR distribution in human head of antenna used in wireless power transform based on magnetic resonance

Feixiang Gong, Zhiqiang Wei, Yanping Cong, Haokun Chi, Bo Yin, Mingui Sun, Edward J. Ciaccio, Feng Liu
2017 Technology and Health Care  
The local and average SAR were simulated at the resonance frequency of 18.67 MHz in two situations, in one scenario both transmitting and receiving coil worked, while in the other scenario only the transmitting  ...  In order to verify the electromagnetic radiation safety on the human head, the electromagnetic intensity and specific absorption rate (SAR) were studied by finite-difference-time-domain (FDTD) method.  ...  The local and average SAR were simulated at the resonance frequency 18.67 MHZ.  ... 
doi:10.3233/thc-171342 pmid:28582927 fatcat:25oo4k7am5er7iqnfg36lyvcke

SAR analysis in a realistic grounded human head for radiating dipole antenna

Faruk Ali, Sudhabindu Ray
2011 2011 National Conference on Communications (NCC)  
Results obtained from the simulation show that maximum local SAR increases significantly for smaller mass average.  ...  Maximum 0.1-g SAR of 3.75 W/kg is obtained for 4 mm distance between head and antenna with 0.6 W radiated power.  ...  Simulated SAR values are compared with the available safety limits. The study is farther extended to higher resolution of 0.1-g SAR where safety standards are not available.  ... 
doi:10.1109/ncc.2011.5734736 fatcat:4iva52szw5gpbjtuexxqxmoyai

A method for safety testing of radiofrequency/microwave-emitting devices using MRI

Leeor Alon, Gene Y. Cho, Xing Yang, Daniel K. Sodickson, Cem M. Deniz
2014 Magnetic Resonance in Medicine  
In this study, we investigated the application of MR temperature mapping and 10-g average specific absorption rate (SAR) computation for safety evaluation of RF-emitting devices.  ...  Results-The maximum temperature change for a dipole antenna and the maximum 10-g average SAR were 1.83° C and 12.4 W/kg, respectively, for simulations and 1.73° C and 11.9 W/kg, respectively, for experiments  ...  Collins and Yudong Zhu for input on EM field simulations and MR thermometry, Ricardo Otazo for help with L1 norm minimization, Theodore S.  ... 
doi:10.1002/mrm.25521 pmid:25424724 pmcid:PMC4442746 fatcat:6t46wwforbhjdlcbysgifib5gu

SAR in Parallel Transmission

Ingmar Graesslin, Dennis Glaesel, Sven Biederer, Ferdinand Schweser, Peter Vernickel, Peter Börnert, Bjoern Annighoefer, Henry Stahl, Henk Dingemans, Giel Mens, Paul Harvey, Ulrich Katscher
2008 PIERS Online  
A good correlation between SAR simulations and measured temperature was obtained, so that the FDTD method can be considered to be a valuable tool in determining (local) SAR for patient safety in multi-channel  ...  Phantom SAR simulations were carried out and validated by temperature measurements.  ...  Furthermore, the SAR simulations of the cuboid phantom were validated by temperature measurements for the assessment of safety and coil performance.  ... 
doi:10.2529/piers071221203006 fatcat:togppxtckndxldksqrsr7q34iq

In vivo human head MRI at 10.5T: A radiofrequency safety study and preliminary imaging results

Alireza Sadeghi-Tarakameh, Lance DelaBarre, Russell L Lagore, Angel Torrado-Carvajal, Xiaoping Wu, Andrea Grant, Gregor Adriany, Gregory J Metzger, Pierre-Francois Van de Moortele, Kamil Ugurbil, Ergin Atalar, Yigitcan Eryaman
2019 Magnetic Resonance in Medicine  
To ensure safety of subjects, we validated the electromagnetic simulation model of our coil.  ...  We obtained quantitative agreement between simulated and experimental B 1 + and specific absorption rate (SAR).  ...  A good agreement between the simulated and measured SAR values was achieved (i.e., RMSE = 0.69 W/kg). | Investigating RF safety In this work, CP-mode of excitation was chosen for imaging.  ... 
doi:10.1002/mrm.28093 pmid:31751499 fatcat:kmsmk7t5sffj5mfghhwx5my62u

Evaluation of the Specific Absorption Rate for Simultaneous Multi-Frequency RF Excitations in 7-T Magnetic Resonance Imaging

Jeung-Hoon Seo, Young Noh, Kyoung-Nam Kim, Yeun Chul Ryu
2017 Journal of Magnetics  
These changes necessitate close monitoring of RF safety by considering other SAR aspects.  ...  Radiofrequency (RF) safety in magnetic resonance imaging (MRI) is mainly verified using the specific absorption rate (SAR) in research involving humans.  ...  All computational calculations were performed by using an electromagnetic (EM) field; more specifically, electric (E)-field simulations with a digital human model that satisfies safety regulations were  ... 
doi:10.4283/jmag.2017.22.4.637 fatcat:hvn4shoblze77kbftpbuxnsjum

Measurement of SAR-induced temperature increase in a phantom and in vivo with comparison to numerical simulation

Sukhoon Oh, Yeun-Chul Ryu, Giuseppe Carluccio, Christopher T. Sica, Christopher M. Collins
2013 Magnetic Resonance in Medicine  
to ensure safety in MR imaging.  ...  Purpose-Compare numerically-simulated and experimentally-measured temperature increase due to Specific energy Absorption Rate (SAR) from radiofrequency fields.  ...  (in addition to higher relevance to safety) over simulation of SAR alone.  ... 
doi:10.1002/mrm.24820 pmid:23804188 pmcid:PMC3842374 fatcat:p746s672hrdepac4pebqolwnqa

Personal Safety in Electromagnetic Environment of Electric Vehicle

Cheng Qiang, Du Zhong-min
2016 International Journal of Signal Processing, Image Processing and Pattern Recognition  
human body SAR value, so conclusion can be drawn that automotive electromagnetic environment is relatively safe to passengers.  ...  This paper established a relatively sophisticated car simulation model,through electromagnetic characteristics of antenna model, we got automotive electric field distribution and simulation results of  ...  The authors would very much like to thank colleagues of State Key Lab of Coal Resources and Safety Mining.  ... 
doi:10.14257/ijsip.2016.9.6.09 fatcat:mgxhvb4runb25ijbxqn6cioeby
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