A joint team from UOsaka has uncovered the core principles of the loss maximization in rotor-driven gas-liquid two-phase flows. Performing numerical simulations on the supercomputer "SQUID", they identified the causes as direct collisions between the rotor and the liquid surface and pressure imbalances around the rotor. The findings suggest that, in a resonant state, the enhanced fluid motion is drawn toward the front of the rotor, and the flow instability is intensified behind it. The insights from this research would open the possibility of improving energy efficiency, enhancing reliability and lifespan, and providing new design guidelines for various industrial applications.

Radiative cooling textiles with spectrally selective surfaces offer a promising energy-efficient approach for sub-ambient cooling of outdoor objects and individuals. However, the spectrally selective mid-infrared emission of these textiles significantly hinders their efficient radiative heat exchange with self-heated objects, thereby posing a significant challenge to their versatile cooling applicability. Herein, we present a bicomponent blow spinning strategy for the production of scalable, ultra-flexible, and healable textiles featuring a tailored dual gradient in both chemical composition and fiber diameter. The gradient in the fiber diameter of this textile introduces a hierarchically porous structure across the sunlight incident area, thereby achieving a competitive solar reflectivity of 98.7% on its outer surface. Additionally, the gradient in the chemical composition of this textile contributes to the formation of Janus infrared-absorbing surfaces: The outer surface demonstrates a high mid-infrared emission, whereas the inner surface shows a broad infrared absorptivity, facilitating radiative heat exchange with underlying self-heated objects. Consequently, this textile demonstrates multi-scenario radiative cooling capabilities, enabling versatile outdoor cooling for unheated objects by 7.8 °C and self-heated objects by 13.6 °C, compared to commercial sunshade fabrics.

Knots are everywhere — from tangled headphones to DNA strands packed inside viruses — but how an isolated filament can knot itself without collisions or external agitation has remained a longstanding puzzle in soft-matter physics.

Now, a team of researchers at Rice University, Georgetown University and the University of Trento in Italy has uncovered a surprising physical mechanism that explains how a single filament, even one too short or too stiff to easily wrap around itself, can form a knot while sinking through a fluid under strong gravitational forces. The discovery, published in Physical Review Letters, provides new insight into the physics of polymer dynamics, with implications ranging from understanding how DNA behaves under confinement to designing next-generation soft materials and nanostructures.