New autopsy technique in COVID-19 positive dead bodies: opening the thoracic cavity with an outlook to reduce aerosol spread.

Aims: After the advent of the COVID-19 pandemic, most countries have modified some of their health-related regulations. However, this has not been in the case of the postmortem of deceased because it has a legal aspect. Thus, the healthcare providers knowingly or unknowingly faced the threat of COVID-19 exposure from those dead bodies.

Tandem solar cells made from amorphous silicon and polymer bulk heterojunction sub-cells.

A tandem solar cell based on a combination of an amorphous silicon (a-Si) and polymer solar cell (PSC) is demonstrated. As these tandem devices can be readily fabricated by low-cost methods, they require only a minor increase in the total manufacturing cost. Therefore, a combination of a-Si and PSC provides a compelling solution to reduce the cost of electricity produced by photovoltaics.

Mechanism of polymer drag reduction using a low-dimensional model.

Using a retarded-motion expansion to describe the polymer stress, we derive a low-dimensional model to understand the effects of polymer elasticity on the self-sustaining process that maintains the coherent wavy streamwise vortical structures underlying wall-bounded turbulence. Our analysis shows that at small Weissenberg numbers, Wi, elasticity enhances the coherent structures. At higher Wi, however, polymer stresses suppress the streamwise vortices (rolls) by calming down the instability of the streaks that regenerates the rolls.