The hydrodynamic and thermal interactions between neighboring vapor bubbles on hot surfaces play a crucial role in heat transport and flow characteristics. To investigate these interactions, we conducted numerical simulations of saturated vapor bubbles in a two-dimensional square enclosure filled with liquid water. The water was heated at the bottom and cooled at the top to replicate boiling at 100^{∘}C and normal atmospheric pressure. In our simulations, we varied the Jakob number (Ja), which measures sensible heat to latent heat, and the separation distance (d) between the bubbles. We observed that the flow zone between the bubble seeds is thermally active and stable for d less than half the height of the enclosure, and becomes oscillatory for d greater than half the height. The stable state leads to a dipole mode, while the oscillatory state triggers a tripole mode. When Ja exceeds a critical value (approximately 2.8), hydrodynamic instabilities are induced in both the core bulk region and the boundary layers. At high Ja values, bubbles frequently move away from the wall, leading to intense hydrodynamic fluctuations and a monopole mode. Our findings indicate that at low Ja, the phase-change-related heat transport dominates, while at high Ja, the convective terms predominate. Furthermore, we observed that overall heat transport in bubbly convection is consistently greater than in classical thermal convection.
Copper and its alloys with transition metals (as good conductors of electricity and heat) are extensively used in electrical industry, electronics, and cooling systems and can be the subject of surface degradation by oxidation. In certain circumstances, surface degradation of copper occurs catastrophically. Predicting catastrophic oxidation kinetics and developing protective technology require understanding the mass transfer mechanisms in the solid/liquid/gas composite scale formed on the copper surface during catastrophic degradation.
Drought is a persistent and serious threat to crop yield and quality. The identification and functional characterization of drought tolerance-related genes is thus vital for efforts to support the genetic improvement of drought-tolerant crops. Barley is highly adaptable and renowned for its robust stress resistance, making it an ideal subject for efforts to explore genes related to drought tolerance.
Grossly lipaemic samples are a significant cause of analytical errors, potentially impacting patient care. The causes of lipaemia are varied and often unavoidable, while methods to reduce lipaemia through gold-standard ultracentrifugation are limited by availability, transportation, and cost. Benchtop centrifugation has been proposed as an alternative method to reduce lipaemia.
The Atlantic Meridional Overturning Circulation (AMOC) is a key component of the global climate that is projected to weaken under future anthropogenic climate change. While many studies have investigated the AMOC's response to different levels and types of forcing in climate models, relatively little attention has been paid to the AMOC's sensitivity to the rate of forcing change, despite it also being highly uncertain in future emissions scenarios. In this study, I isolate the AMOC's response to different rates of CO increase in a state-of-the-art global climate model and find that the AMOC undergoes more severe weakening under faster rates of CO change, even when the magnitude of CO change is the same.
When water is confined in a nanochannel, its thermodynamic and kinetic properties change dramatically compared to the macroscale. To investigate these phenomena, we conducted nonequilibrium molecular dynamics simulations on the heat transfer in copper-water nanochannels with lengths ranging from 12 to 20 nm in the absence and presence of an electric field. The results indicate that in the absence of an electric field ( = 12-20 nm), the binding force between water molecules in the 20 nm nanochannel is the weakest, facilitating thermal motion in the liquid phase.
