Record-high heat transfer performance of spray cooling on 3D-printed hierarchical micro/nano-structured surface.

Managing high-flux waste heat with controllable device working temperature is becoming challenging and critical for the artificial intelligence, communications, electric vehicles, defense and aerospace sectors. Spray cooling, which combines forced convection with phase-change latent heat of working fluids, is promising for high flux heat dissipation. Most of the previous studies on spray cooling enhancement adopted high spray flow rates to strengthen forced convection for high critical heat flux (CHF), leading to a low heat transfer coefficient (HTC).

A heat transfer model for liquid film boiling on micro-structured surfaces.

High heat transfer coefficient (HTC) and critical heat flux (CHF) are achieved in liquid film boiling by coupling vibrant vapor bubbles with a capillary liquid film, which has thus received increased interest for thermal management of high-power electronics. Although some experimental progress has been made, a high-fidelity heat transfer model for liquid film boiling is lacking. This work develops a thermal-hydrodynamic model by considering both evaporation atop the wick and nucleate boiling inside the wick to simultaneously predict the HTC and CHF.

Impact of the coronavirus disease 2019 interventions on the incidence of hand, foot, and mouth disease in mainland China.

Background: In early 2020, non-pharmaceutical interventions (NPIs) were implemented in China to reduce and contain the coronavirus disease 2019 (COVID-19) transmission. These NPIs might have also reduced the incidence of hand, foot, and mouth disease (HFMD).

Methods: The weekly numbers of HFMD cases and meteorological factors in 31 provincial capital cities and municipalities in mainland China were obtained from Chinese Center for Disease Control and Prevention (CCDC) and National Meteorological Information Center of China from 2016 to 2020.

Experimental study and predicted model analysis of nanofluid wetting behavior under high voltage.

To explore the wetting behavior of nanofluid under high voltage, a contact angle measurement system under electric field is designed and set up. The effects of mass concentration, the type of nanoparticles and the temperature of dielectric layer are considered. The experimental results manifest that the contact angle reduction rate of SiO-water nanofluid is gradually increased with the increase of nanofluid concentrations from 0 to 0.