PMC:7796291 / 10556-11150 JSONTXT

{"project":"LitCovid-sentences","denotations":[{"id":"T94","span":{"begin":0,"end":212},"obj":"Sentence"},{"id":"T95","span":{"begin":213,"end":313},"obj":"Sentence"},{"id":"T96","span":{"begin":314,"end":594},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"FE-SEM images of filter samples were observed by Supra 55 VP (Zeiss, Oberkochen, Germany), with prior coating with Pt at 20 mA for 120 s, using a 108auto sputter coater (Cressington Scientific Inc., Watford, UK). The thickness of respirator layers was measured using a thickness gauge under the pressure of 2.4 N. Porosity and solidity of webs were calculated based on Equations (1) and (2), where m is mass of the material, A is area of the material, t is thickness, and ρ is the material density (0.95 g/cm3 for PP was used):Porosity (%) = (1 − solidity) × 100 (%)(1) Solidity = m/(A⋅t⋅ρ)(2)"}