key: cord-1025140-rfy2jkp9
authors: Das, Hirak Ranjan; Bhatia, Dinesh; Das, Kalyan Kr; Mishra, Animesh
title: Development of Viroreaper sanitization chamber for COVID 19
date: 2020-10-28
journal: Sensors international
DOI: 10.1016/j.sintl.2020.100052
sha: c4131abf50134f613f6a3d1c40598207c162a282
doc_id: 1025140
cord_uid: rfy2jkp9

The whole world at present is dealing with the COVID 19 pandemic. As per studies worldwide SARS-CoV-2 by sequencing analysis is 95% homogenous similar to the bat coronavirus and almost 70% similar to the SARS-CoV-1. SARS CoV 2 is a respiratory problem which in its worst form of disease causes ARDS and hampers the patient's ability to breathe on his own and has to be put on Ventilator. As per WHO (World Health Organization) guidelines, sanitization is an effective way of prevention from the infection. The proper sanitization being not feasible and time consuming in certain cases, faster and effective alternatives of sanitization processes are necessary. As per recently published study by researchers in Beijing, China, it was observed that with each degree rise in temperature and percent humidity, the contagiousness of the disease caused by the Coronavirus, named COVID 19 goes down significantly. R-naught or RO can be referred as the average number of people that gets infected from one sick person among a population which is not immune to the virus. The closer to zero an RO value the better the results indicating less spread of the disease. A lower RO means the outbreak is slowing or declining while a higher one means its swelling or growing at faster rate. The RO of the coronavirus hovers between 2 and 2.5 as per World Health Organization or WHO meaning that each new person spreads the disease to about 2.2 people on an average. The chamber being developed is aimed at lowering the Ro value so that the infection rate slows down. RO is not a fixed value, it changes depending on various factors such as proximity among people, the environmental surroundings and climatic conditions. The higher temperatures (38 °C) at 80–90% relative humidity decreases the virus activity within 24 h. Moreover, in a condition where the virus that was dried was stored at higher temperature (>38 °C) and high relative humidity (>95%), there was observed an additional degradation in virus activity at each point in time. Taking into consideration the above research, we developed a COVID De-Incubator chamber to disinfect the clothes and commonly used daily wear items. Our results were exciting as the disinfection proved to be effective at temperatures of 75 °C–80 °C and humidity levels at 80%–90%. Moreover, the chamber was developed at significantly lower costs. In this study, an attempt has been made to fabricate a chamber with temperature and humidity-controlled environment to disinfect daily used material. Using fins and momentum source, a homogenous environment is created inside the chamber for better results, with the help of numerical simulation to decide the optimum angle for the inclination of fins and location of the momentum source.

COVID 19 pandemic has spread all over the world and as per WHO, till date fifty five lakhs people are infected worldwide and more than three lakhs have died due to this contagious disease with numbers increasing rapidly with each passing day. In absence of proper vaccine and medication, the only way to restrict the infection rate is early diagnosis and separation of infected people from the remaining population to prevent community spread. The detection of the Corona virus infection at an early stage proves to be helpful in isolating the infected individuals by social distancing or self-quarantine at their homes for a period of fourteen to twenty days which prevents the spread of this viral disease. The patients are screened at hospitals or airports with help of thermal or infra-red scanners, which are not reliable as symptoms in asymptomatic individuals for the disease may prevail and occur after few days and not immediately when scanned with the thermal device such as thermometer which are being widely deployed at different screening facilities. By that time these asymptomatic individuals have already mixed in the society and spread the disease multifold making it a dreaded communicable disease affecting millions globally with fast rate of replication. Hence, a long-lasting and potent solution to the pandemic is the need of the hour which has still not been successfully evolved despite ongoing efforts globally and on warpace [2] . where temperatures were closer to 95 o Fahrenheit (35 o C). It was found that at elevated relative humidity (>95%) with comparatively low temperatures (28°C and 33°C) failed to affect the infectivity of the virus significantly. However, higher temperatures (38°C) at 80-90% relative humidity led to some decrease in virus activity within 24 hours. Moreover in a condition where the virus that was dried was stored at higher temperature (>38°C) and high relative humidity (>95%), there was observed an additional degradation in virus activity at each point in time [3] .

Taking into consideration the above research, a collaborative team comprising of faculty, scientists, doctors and industrialist developed a COVID Viroreaper sanitiser chamber to disinfect the clothes and commonly used daily wear items. After more than two months of research, discussions, trials and testing, the machine has been made compact and cost effective. The prototype-testing has been completed and field trials results were found to be satisfactory. The working of the machine can be explained by the concept of elevated temperature heating and exposure to humidity and it is assumed to be effective in controlling the virus. The temperature is maintained between 75 o C to 80 o C with humidity levels 

According to experiments conducted by Hindawi , ten microlitre of maintenance medium containing 10 7 TCID 50 ( Median Tissue Culture Infectious Dose) per mL of virus was placed in individual wells of a 24-well plastic plates and allowed to dry at room temperature J o u r n a l P r e -p r o o f (22~25°C) and relative humidity of 40-50% (i.e., conditions prevailing in a typical airconditioned room). TCID 50 is a method which is used to verify viral titer. They have noticed that if the intensity at which 50% of cells are affected when a test tube upon which cells have been cultured is injected with a dilute solution of viral fluid. One hundred microlitre of MM (Mouse-brain stock) was used to re-suspend the virus at 0 hr, 3 hr, 7 hr, 11 hr, 13 hr, 24 hr, and up to 4 weeks and the residual virus infectivity was titrated. Controls were included in closed screw cap eppendorf tube every time while treating in the same manner but drying was avoided. The experiment was performed at varying temperatures (28°C, 33°C, 38°C) and relative humidities (80~89%, >95%) for 3 hr, 7 hr, 11 hr, 13 hr, and 24 hr. All the abovementioned experiments were conducted in duplicate and the viral infection which was residual was titrated [3, 4] .

Higher relative humidity (>95%) at lower temperatures in comparison (28°C and 33°C) affected the infectivity of the virus significantly less (Figure 1.1) . At temperature 38°C and 80-90% relative humidity led to a 0.25~2 log 10 loss of titre at 24 hr (Figure 1(b) ).

Moreover, the dried virus when stored at higher temperature (38°C) accompanied by higher relative humidity (>95%), ~1.5 additional loss of titre is observed for every single time point 

For a turbulent flow the shear stress can be expressed by the Eq. 3.5. The above equations (Eq. 3.6 and Eq. 3.7) are solved for turbulence model by using SST model. The basis of the SST model is the "k-ω" model which comprises of the identical automatic wall treatment which is combination of a "k-" model (in the inner boundary layer) and "k-" model (in the outer region).

For Cartesian co-ordinate system turbulent incompressible fluid flow continuity equation is written as in the Eq. 3.8 [6] .

Equation for dissipation rate of energy is known as k-model. Here the term rate of energy loss per unit volume can be given by inside the chamber. This air alkaline water mixer at the elevated temperature (or state temperature at 70 0 C) and higher relative humidity is found to decrease the infectivity of the virus from the items present in the chamber. Numerical simulation is carried out using commercially available software ANSYS 19. 

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Animesh Mishra, 2020, Study and Overview of the Novel Corona Virus Disease (COVID-19)