No abstract

With the ongoing global pandemic due to Coronavirus (COVID-19), the use of personal protective equipment (PPE), specifically single-use surgical masks, have been on a sharp incline. Currently, many countries are experiencing second and third waves of COVID-19 and as such have resorted to making face masks a mandatory requirement. The repercussions of this have resulted in millions of single-use face masks being discharged into the environment, washing up on beaches, floating beneath oceans and ending up in vulnerable places. The global pandemic has not only affected the economy and health of the world’s population but now is seriously threatening the natural environment. The main plastic in single-use face masks is polypropylene which in landfill can take approximately 25 years to break down. This paper explores an innovative way to use pandemic waste in concrete construction with the main focus on single-use face masks. Single-use masks have been cut-up by first removing the ear loops and inner nose wire to size and spread throughout five different mix designs to explore the possible benefits and uses within concrete. The masks were introduced by volume at 0% (control), 0.10%, 0.15%, 0.20% and 0.25% with testing focusing on compressive strength, indirect tensile strength, modulus of elasticity and ultrasonic pulse velocity to test the overall quality of the concrete. The introduction of the single-use face masks led to an increase in the strength properties of the concrete samples, as well as an increase in the overall quality of the concrete. However, beyond 0.20%, the trend of increasing strength began to decrease.

The COVID-19 pandemic not only has created a global health crisis but also has dramatic effects on the environment. To fight the spread of Coronavirus, governments imposed social distancing policies, which caused negative and positive impacts on the environment. Victoria, the second-most populated state in Australia, was hit by two waves of COVID-19. During the second wave of the pandemic, Victoria, especially Melbourne, experienced one of the most stringent and longest lockdowns globally. In this study, the changes in mobility trends, traffic, air pollution, noise pollution, and waste generation during the first and second waves of COVID-19 in Victoria are evaluated and compared. It was observed that the pandemic had both positive and negative impacts on the environment. During the second wave of the pandemic in Victoria, the mobility trends of public transport hubs, retail and recreation venues, and workplaces experienced a significant drop in movements at respective values of 85%, 83%, and 76% compared to the period of 5 weeks from 3 January to 6 February 2020. PM 2.5 levels were lower by 23% at Alphington and 24% at Footscray from 16 March to 1 May 2020 compared with the average PM 2.5 levels in the past 4 years. It was estimated that the respective daily generations of used face masks during the first wave and second wave of the pandemic in Victoria were approximately 104 and 160 tons.

In industrial fluid cokers, the feedstock, consisting of heavy bituminous hydrocarbons, is atomized with steam and injected into the hot fluidized bed of coke. Good and uniform contact of the liquid droplets with the solid particles is required to provide heat for the cracking reactions while mass transfer effects are minimized. Experiments in a pilot plant coker have suggested that the initial particle/liquid mixing, in the spray jet, is rather poor. Experiments in a X-ray scanner showed that liquid droplets and entrained particles accumulate just below the tip of the jet plume. To illustrate the importance of the initial liquid-solid mixing, a simple model has been proposed to predict its effect on coker yields. An experimental technique was developed to quantitatively determine the quality of mixing with current nozzle technology and a new enhanced solids entrainment (ESE) device. The model has been used in combination with the experimental results to show the effect of ESE on product yields. The ESE nozzle has been shown to greatly improve liquid/solid mixing by increasing the amount of wetted solids and achieving a more uniform initial liquid/solid mix. The model suggests that ESE will improve liquid yield by up to 0.6 wt % and reduce the coke yield by up to 2 wt %.