Abstract

The main idea of new equipment is connected with the rotation of contaminated fluid by screw channels of meta-materials, prepared from UVC fiber/spherical optics in order to improve the decontamination efficiency. © 2021 The Author(s)

Keywords: OCIS codes: 120.3890 Medical optics instrumentation, Meta-materials; Evanescent zone; Decontamination; Viruses and bacteria, Spinning effect

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Introduction and Main Idea

Pathogens (viruses and bacteria) can reach the organism not only through transmission traditional mechanisms like direct contact with other persons but in the last time is observed the positive correlation has been observed between the spread of the virus and fluids (water or air) pollution [1]. COVID-19 could have an air/water transmission trough particulate matter could create a suitable environment for transporting the virus at greater distances than those consid- ered for close contact. SARS-CoV-2 is an enveloped virus 0.1µmin diameter. Viruses are often transmitted through respiratory droplets produced by coughing and sneezing. Respiratory droplets are usually divided into two size bins, large droplets (>5µmin diameter) that fall rapidly to the ground and are thus transmitted only over short distances, and small droplets (< 5µm in diameter). Small droplets can evaporate into ’droplet nuclei’, remain suspended in air for significant periods of time and could be inhaled [2]. As a usual they are not transparent in UVC decontamination dia- pason (200-280 nm) and needs a more near action of such radiation obtained from traditional sources from all direction to such droplets in order to achieve a good effect.

Figure 1. The contaminated by pathogen droplets (A) with dimensions about 10 100nm can be pumped and imposed under rotation acceleration between free space of helical ensemble of the scrolled fibers (B). Achieving the evanescent zone of UVC radiation of each fiber the pathogens can be effectively inactivated.

The main idea is connected with the rotation of contaminated liquids and gases by screw channels of meta-materials, prepared from UVC fiber optics in the torsion configuration represented in the Figs. 1and 2. The contamination liquids are rotated along the flow direction. Considering that the density of virus and bacteria droplets are larger than the density of liquids, the adherence of the pathogens to the ”external surface” of the rotation channels increases as a function of the torsion degree of channels [3, 4]. As the number of such rotation canals in the proposed meta-material is large, the total surface consists of the sum of the surfaces of each flow canal between the fibers. This UVC decontamination effect depends on the inertial centrifugal force, which appear on the droplets infected by pathogens during its rotation flow along the channel. The large density of pathogens gives us the possibility to find the connection between its flow velocity and spinning radius of rotation channel. The centrifugal force must pull the pathogen droplets to the fibers/sphere surface penetrated by evanescent UVC radiation in the flow channel during the spinning effect (see Fig. 2). This UVC decontamination effect depends on the inertial centrifugal force, which appears on the pathogens during its rotation flow along the channel.

Figure 2.

Figure 3. The acceleration of the pathogens around the elements of meta-material and possible turbulent flow with the acceleration of the pathogens in the circle or Screw Channels in the three-dimension case (see fig A and B). If the density of the pathogens is higher than the density of the fluids the viruses or bacteria can stick to the surface of spheres of metamaterial elements penetrated by ultraviolet C radiation.

Experimental Results

It is complicated to use pathogens in the decontamination procedures in the physics laboratory. But taking into consid- eration that the big number of pathogens are sensible to UVC radiation than eukaryotic cellular structures, we have to substitute these contaminated fluids with yeast solution, which has larger resistance to UVC radiation in comparison with many viruses or bacteria. In this approach, the improving of the inactivation rate of the yeast colony using this type of metamaterial will mean that this efficient method will work successfully well in the case of prokaryotic cells specific for many bacteria.

Figure 4. The decontamination core (C) filled up by scrolled fibers (A or balls (B). All system of lamps and decontamination core is introduced in the big aluminum cylinder with diameters about 20 cm represented in Fig C.

For obtaining good experimental results was take 2.1L of water in which was dissolved 80Gr of yeast and added 440Gr of sugar. After some Min the dynamical (see Fig. 4) and static (see Fig.5) experiments began. Our decontami- nation core with 0.8 M length and 2.5 cm in diameter is filled up with a diameter of spheres about 0.5 − 1mmof the

Figure 5. The decontamination procedure of 1.5L of yeast solution in which the fungus colonies was measured after 3, 5, 7, and 10 Min in dynamic regime. Beginning with 7 and 10Minthe fungus colonies are not observed with our optical microscope. We mention that during the cyclical pump of 1.5L of solution through the meta- material element of our equipment only 0.15Lpart of the solution was under the UVC radiation. The remaining part was in the cyclical moving.

Quartz material. The core is covered by 6 mercurial lamps which a maximum of radiation is 250-260 nm. To improve the efficiency of UVC radiation all the system is placed in the aluminum cylinder with the diameter about 20cmso that the intensity of the radiation in the center of the big cylinder increase significantly due to the reflection proprieties of the aluminum. More than this the researchers and people from the room are well protected from the direct action of UVC radiation obtained from 6 lamps represented in the Fig.3.

Figure 6. The inactivation of fungus from the yeast solution in the static regime under the direct UVC exposition of a small quantity of water 0.15Lduring the time intervals: 0.3Min, 1.0Min, 2Min, 3Min. It is observed that at the beginning with 3Minof exposition the fungus colonies are totally deactivated.

Conclusions

The decontamination efficiency is connected with the rotation of contaminated liquids and gases by screw channels of meta-materials, prepared from UVC fiber optics (or close packed spherical elements of metamaterial) in the torsion configuration. The contamination liquids are rotated along the flow direction. Considering that the density of viruses and bacteria (or droplets, aerosols contained they) are larger than the density of liquids, the adherence of the pathogens on the rotation channels increases as a function of the torsion degree of the channels. As the number of such relative canals in the proposed meta-material is large, the total surface consists of the sum of the surface of each flow canal between the fibers.

Acknowledgments: This paper is supported by the projects: No. 20.80009.5007.01 and NATO EAP SFPP 984890.

References

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