Publications by authors named "Lewis S Jones"

2 Publications

  • Page 1 of 1

Protection Level and Reusability of a Modified Full-Face Snorkel Mask as Alternative Personal Protective Equipment for Healthcare Workers during the COVID-19 Pandemic.

Chem Res Toxicol 2021 01 17;34(1):110-118. Epub 2020 Dec 17.

Institute of Environmental Engineering, Department of Civil, Environmental and Geomatic Engineering, ETH Zurich, Zurich 8093, Switzerland.

The worldwide outbreak of COVID-19 has drastically increased pressure on medical resources and highlighted the need for rapidly available, large-scale, and low-cost personal protective equipment (PPE). In this work, an alternative full-face mask is adapted from a modified snorkel mask to be used as PPE with two medical-grade filters and a 3D-printed adapter. Since the mask covers the eyes, mouth, and nose, it acts as a full-face shield, providing additional protection to healthcare workers. The SARS-CoV-2 has a size between 60 nm and 140 nm, and airborne viral particles can be carried by larger droplets with sizes up to several millimeters. The minimum filtration efficiency of mechanical and electrostatic filters is usually reached between 30 nm and 300 nm. The filtration efficiency of different medical filters is measured for particles below 300 nm to cover the size of the SARS-CoV-2 and small virus-laden droplets, and determine the minimum efficiency. The filtration performance of the adapted full-face mask is characterized using NaCl particles below 500 nm and different fitting scenarios to determine the minimum protection efficiency. The mask is compared to a commercial respirator and characterized according to the EN 149 standard, demonstrating that the protection fulfills the requirements for the FFP2 level (filtering face-piece 2, stopping at least 94% of airborne particles). The device shows a good resistance to several cycles of decontamination (autoclaving and ethanol immersion), is easy to be produced locally at low cost, and helps to address the shortage in FFP2 masks and face shields by providing adequate protection to healthcare workers against particles <500 nm in size.
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January 2021

Increased Longevity and Pumping Performance of an Injection Molded Soft Total Artificial Heart.

Soft Robot 2021 Oct 23;8(5):588-593. Epub 2020 Sep 23.

Department of Chemistry and Applied Biosciences, Institute for Chemical- and Bioengineering, ETH Zurich, Zurich, Switzerland.

In this work, we present an injection molded soft total artificial heart (sTAH) produced from high-temperature vulcanizing silicone using an industrial metal injection mold. At 60 beats per minute, the sTAH exhibited a total cardiac output of over 16‚ÄČL/min against physiological pressures on a mock circulation and was pumped continuously for 110,000 actuation cycles. Finite element analysis was used to identify stress concentrations within the sTAH, allowing an optimized design to be proposed.
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October 2021