BackgroundReducing COVID-19 transmission relies on controlling droplet and aerosol spread. Fluorescein staining reveals microscopic droplets.AimTo compare the spread in non-laminar laminar air flow operating theatres.MethodsA ‘cough-generator’ was fixed to a theatre trolley at 45°. Fluorescein-stained ‘secretions’ were projected series of calibrated targets. These photographed under UV light ‘s...

Human respiratory events, such as coughing and sneezing, play an important role in the host-to-host airborne transmission of diseases. Thus, there has been a substantial effort understanding these processes: various analytical or numerical models have developed to describe them, but their validity not fully assessed due difficulty direct comparison with real human exhalations. In this study, we...

Droplets impacting and penetration into porous media is commonly seen in natural engineering processes, which the kinetics capillary effect are of great importance to lateral spreading vertical penetration. In this study, a three-dimensional numerical simulation method was proposed study micro-meter droplet impact media. It found that both spread occur on millisecond timescale larger velocity w...

Abstract In this paper interparticle potential model of the lattice Boltzmann method (LBM) is used to simulate deformation and breakup of a falling droplet under gravity force. First this model is applied to ensure that the surface tension effect is properly implemented in this model. Two tests have been considered. First, it has been checked an initial square drop in a 2D domain can freely def...

OBJECTIVE To describe the outbreak of severe acute respiratory syndrome in Hong Kong. DESIGN Descriptive case series. SETTING Hong Kong, Special Administrative Region, China RESULTS The outbreak started with a visitor from southern China on 21 February. At the hospitals where the first cases were treated the disease spread quickly among healthcare workers, and then out into the community ...

BACKGROUND Adjuvants can improve pesticide application efficiency and effectiveness. However, quantifications of the adjuvant-amended pesticide droplet actions on foliage, which could affect application efficiencies, are largely unknown. RESULTS Droplet evaporation rates and spread on waxy or hairy leaves varied greatly with the adjuvant types tested. On waxy leaves, the wetted areas of dropl...

for evaluation of citric acid and citrate effects on bovine epididymal protoplasmic droplets, fifty bovine testes were collected in the october 2007 till june 2008 from urmia slaughterhouse and transported to the laboratory in a cool container filled with 5 °c ice pack. caudal epididymis was incised and sperm cells were put into petri dishes containing hams f10 media with 10% fetal calf serum (...

In this paper the dynamic of a droplet on a surface with a hole is investigated under gravitational effect by using lattice Boltzmann method. Incompressible two-phase flow with high density ratio proposed by Lee is considered. Cahn’s theory is used to observe the wettability of the surface in contact with liquid and gas phases. Several parameters such as contact angle, surface tension and gravi...

A modified model has been analytically developed to describe the induction time of an elliptic air bubble in contact with an elliptic hydrophobic oil droplet. The role of hydrophobicity was revealed in the slippage of liquid over the surfaces of bubble and droplet. In this condition, the analytical relationships for pressure distribution and consequently hydrodynamic resistance force through th...