A Novel Algorithm for Determining Contact Area Between a Respirator and a Headform

Lei, Zhipeng; Yang, James; Zhuang, Ziqing

doi:10.1080/15459624.2013.858818

Cited by 17 publications

(16 citation statements)

References 14 publications

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“…Coffey et al 17 measured the TIL for 21 models of N95 respirators on 25 different subjects and observed that the TIL value could be as high as 88% in the absence of fit testing. Lei et al 18 and Cai et al 15 developed a “contact pressure” model to estimate gaps between the face and N95 respirators. Cai et al 14 evaluated the effect of facial expression on contact characteristics between an N95 filtering facepiece respirator and a headform.…”

Section: Introductionmentioning

confidence: 99%

A computational model for predicting changes in infection dynamics due to leakage through N95 respirators

Hariharan

Sharma

Guha

et al. 2021

Sci Rep

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In the absence of fit-testing, leakage of aerosolized pathogens through the gaps between the face and N95 respirators could compromise the effectiveness of the device and increase the risk of infection for the exposed population. To address this issue, we have developed a model to estimate the increase in risk of infection resulting from aerosols leaking through gaps between the face and N95 respirators. The gaps between anthropometric face-geometry and N95 respirators were scanned using computed tomography. The gap profiles were subsequently input into CFD models. The amount of aerosol leakage was predicted by the CFD simulations. Leakage levels were validated using experimental data obtained using manikins. The computed amounts of aerosol transmitted to the respiratory system, with and without leaks, were then linked to a risk-assessment model to predict the infection risk for a sample population. An influenza outbreak in which 50% of the population deployed respirators was considered for risk assessment. Our results showed that the leakage predicted by the CFD model matched the experimental data within about 13%. Depending upon the fit between the headform and the respirator, the inward leakage for the aerosols ranged between 30 and 95%. In addition, the non-fit-tested respirator lowered the infection rate from 97% (for no protection) to between 42 and 80%, but not to the same level as the fit-tested respirators (12%). The CFD-based leakage model, combined with the risk-assessment model, can be useful in optimizing protection strategies for a given population exposed to a pathogenic aerosol.

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Section: Introductionmentioning

confidence: 99%

A computational model for predicting changes in infection dynamics due to leakage through N95 respirators

Hariharan

Sharma

Guha

et al. 2021

Sci Rep

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show abstract

“…The approach does not provide reliable isolation of worker's respiratory organs by means of dust respirators and requires the proper studies for digital models development of half masks surfaces to correct their design according to anthropometric parameters of the person's face.Besides, the unification of half masks design to provide fast production with respect to their functions under the working conditions is one of the trends of product-line expansion for IRPD. This results in need of algorithm development for computer assisted design enabling fast corrections and final product prototype [5]. It is important to control the performance of different components of dust respirators continuously both at the stages of design and exploitation; this requires the development of the proper control methods of IRPD operating parameters [6].…”

Section: Fig 2 Distribution Of Users' Faces Into 5 Groups Accordingmentioning

confidence: 99%

Improvement of the procedure of new filter masks development

et al. 2020

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The purpose is to substantiate theoretically the design of elastomeric half mask and canister of respirator of long-term protection. To develop the models for theoretical calculations of protective properties of dust masks the theory of non-stationary filtration and hydro aerodynamics was applied. To develop the digital model of a head the downhill simplex method was applied reflecting separate face features considering sex or age; to determine the halfmask surface the free energy equation for bowed plate being described by two-dimension spline surface was used with its unknown coefficients determined by method of proportional parts based on three-dimension coordinates of anthropometric face features. The main anthropometric face features influencing halfmasks design were determined to develop polygonous 3D model of head. According to its determined basic coordinates the surface of halfmask was determined using method of interpolation. Considering the mathematical model describing the movement of dust flows near a halfmask and in canister the dependences of distribution of air flow speed in a canister of variable geometry were set and kinematic parameters of dust-laden airflow according to a canister volume were determined. Reasonable geometric parameters of canister were determined; transient modulation from filter to inlet valve hole is performed as a contractor.

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“…Постійне вдосконалення засобів захисту органів дихання також вимагає додаткових досліджень енерго-вират гірників під час вуглевидобутку (Campbell, Coffey & Lenhart, 2001;Clayton, 2002;Janssen, Nelson, & Cuta, 2007;Laney & Attfield, 2010;Lee, Grinshpun, & Reponen, 2010;Lei, Yang, & Zhuang, 2014;Golinko, Cheberyachko, Radchuk, & Cheberyachko, 2014;Golinko, Cheberyachko, Cheberyachko, & Naumov, 2014;Golinko, Cheberyachko, Yavorskaya, & Cheberyachko, 2016).…”

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Analysis of miners’ biomechanical characteristics during underground coal mining

Shevchenko¹

2016

Min. miner. depos.

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Purpose. Analysis and establishing regularities of changes in miner's biomechanical characteristics during underground coal mining in order to reduce the number of accidents and injuries in coal mines.Methods. The complex research suggested using methods of mathematical analysis, mathematical statistics, probability theory, reliability theory, control theory, methods of biomechanics.Findings. The influence of miner's biomechanical characteristics on productivity of the system "driver -cutter of the new technological level" is modeled and analyzed. We established regularities of safe operation of the system "driver -cutter of the new technological level" in conditions of the highly loaded face considering the influence of miner's biomechanical parameters and determined limits of the face load for these parameters.Originality. For the first time the dependence of the total energy consumption on the value of cutter performance is established, which indicates that its movement along the face at a constant speed is more economical than moving at a variable speed, with the same average speed in both cases. The authors pioneered in assessing the degree of comfort of miners' working conditions through the indicator of driver energy consumption per ton of excavated rock. It was also proposed to introduce the index of driver's movement efficiency that is inversely proportional to the energy consumption per ton of rock mass and grows parabolically depending on the increase in the cutter speed and linearly in respect to increasing web width. Practical implications.The results are the basis for developing the method for calculating miner's biomechanical parameters in highly loaded face.

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A Novel Algorithm for Determining Contact Area Between a Respirator and a Headform

Cited by 17 publications

References 14 publications

A computational model for predicting changes in infection dynamics due to leakage through N95 respirators

A computational model for predicting changes in infection dynamics due to leakage through N95 respirators

Improvement of the procedure of new filter masks development

Analysis of miners’ biomechanical characteristics during underground coal mining

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