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1.
PLoS One ; 17(3): e0264090, 2022.
Article in English | MEDLINE | ID: covidwho-1753188

ABSTRACT

The objective of this study was to characterize commercially-available cotton fabrics to determine their suitability as materials for construction of cloth masks for personal and public use to reduce infectious disease spread. The study focused on cottons because of their widespread availability, moderate performance and they are recommended for inclusion in home-made masks by international health authorities. Fifty-two cottons were analyzed by electron microscopy to determine fabric characteristics and fabric weights. Sixteen fabrics were selected to test for breathability and to construct 2-ply cotton masks of a standard design to use in quantitative fit testing on a human participant. Cotton mask fitted filtration efficiencies (FFEs) for 0.02-1 µm ambient and aerosolized sodium chloride particles ranged from 40 to 66% compared with the mean medical mask FFE of 55±2%. Pressure differentials across 2-ply materials ranged from 0.57 to > 12 mm H2O/cm2 on samples of equal surface area with 6 of 16 materials exceeding the recommended medical mask limit. Models were calibrated to predict 2-ply cotton mask FFEs and differential pressures for each fabric based on pore characteristics and fabric weight. Models indicated cotton fabrics from 6 of 9 consumer categories can produce cloth masks with adequate breathability and FFEs equivalent to a medical mask: T-shirt, fashion fabric, mass-market quilting cotton, home décor fabric, bed sheets and high-quality quilting cotton. Masks from one cloth mask and the medical mask were re-tested with a mask fitter to distinguish filtration from leakage. The fabric and medical masks had 3.7% and 41.8% leakage, respectively. These results indicate a well fitted 2-ply cotton mask with overhead ties can perform similarly to a disposable 3-ply medical mask on ear loops due primarily to the superior fit of the cloth mask which compensates for its lower material filtration efficiency.


Subject(s)
COVID-19 , Filtration , Gossypium , Humans , Textiles
2.
Rev Ind Organ ; : 1-29, 2021 Nov 14.
Article in English | MEDLINE | ID: covidwho-1527486

ABSTRACT

The U.S. Federal Communications Commission is responsible for regulation in the communications marketplace and for management of the nation's non-federal radio frequency spectrum. During the past year, FCC economists assisted in the development of initiatives that were aimed at closing the connectivity gap which proved especially critical in light of the COVID-19 pandemic; contributed to the Commission's extensive responses to COVID-19; were involved in various spectrum auctions; evaluated competition in the communications marketplace in the 2020 Communications Marketplace Report; and published a series of working papers.

3.
Rev Ind Organ ; 57(4): 827-858, 2020.
Article in English | MEDLINE | ID: covidwho-893322

ABSTRACT

The U.S. Federal Communications Commission is responsible for regulation in the communications marketplace and for management of the nation's non-federal radio frequency spectrum. During the past year, FCC economists helped develop efficient mechanisms for making available more flexible-use spectrum for the deployment of advanced broadband technologies; developed two new universal service funding mechanisms that aim to close the digital broadband divide; and, through careful analysis of firm cost data, contributed to a renewed effort by the Commission to develop price caps for interstate calls on prison inmate calling services. FCC economists also contributed to the Commission's extensive response to COVID-19.

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