In 2018, a discovery in materials science sent shock waves throughout the community. A team showed that stacking two layers of graphene—a honeycomb-like layer of carbon extracted from graphite—at a precise “magic angle” turned it into a superconductor, says Ritesh Agarwal of the University of Pennsylvania.
The physics of drop motion in microchannels is fundamental to provide insights when designing applications of drop-based microfluidics. In this paper, we develop a boundary-integral method to simulate the motion of drops in microchannels of finite depth with flat walls and fixed depth but otherwise arbitrary geometries. To reduce computational time, we use a moving frame that follows the droplet throughout its motion. We provide a full description of the method, including our channel-meshing algorithm, which is a combination of Monte Carlo techniques and Delaunay triangulation, and compare our results to infinite-depth simulations. For regular geometries of uniform cross section, the infinite-depth limit is approached slowly with increasing depth, though we show much faster convergence by scaling with maximum vs average velocities. For non-regular channel geometries, features such as different branch heights can affect drop partitioning, breaking the symmetric behavior usually observed in regular geometries. Moreover, non-regular geometries also present challenges when comparing the results for deep and infinite-depth channels. To probe inertial effects on drop motion, the full Navier–Stokes equations are first solved for the entire channel, and the tabulated solution is then used as a boundary condition at the moving-frame surface for the Stokes flow inside the moving frame. For moderate Reynolds numbers up to Re = 5, inertial effects on the undisturbed flow are small even for more complex geometries, suggesting that inertial contributions in this range are likely small. This work provides an important tool for the design and analysis of three-dimensional droplet-based microfluidic devices.
Particles that are larger than regular molecules or atoms yet remain invisible to the naked eye can form a variety of useful structures, including miniature propellers for microrobots, cellular probes, and steerable microwheels designed for targeted drug delivery.
The James Webb Space Telescope (JWST) is the largest and most powerful space telescope built to date. Since it was launched in December 2021 it has provided groundbreaking insights. These include discovering the earliest and most distant known galaxies, which existed just 300 million years after the Big Bang.
In recent years, quantum physicists and engineers have made significant strides toward the development of highly performing quantum computing systems. Realizing a quantum advantage over classical computing systems and enabling the stable operation of quantum devices, however, will require the development of new building blocks for these devices and other aspects underlying their correct functioning.
A team of engineers and materials scientists at LG Chem, Korea’s largest chemical company, has developed a material that they claim could greatly reduce the risk of thermal runaway and resulting fires in batteries. In their paper published in the journal Nature Communications, the group describes how they developed the material and how well it has worked during testing.
Over the past several years, consumers have witnessed or have heard about batteries in smartphones or cars catching on fire. These fires, it has been found, result from thermal runaway, which is where the anode and cathode inside a battery come too close together, or worse, actually touch.
The result is a short, which generates heat, and results soon thereafter in a fire. In this new effort, the team at LG has developed a thin material that, when placed between the cathode and collector, prevents thermal runaway.
An international research team led by Brandeis University has achieved a major breakthrough in the field of active matter physics, as detailed in a study published this week in Physical Review X. This pioneering research offers the first experimental validation of a key theoretical prediction about 3D active nematic liquid crystals by trapping them within cell-sized spherical droplets.
In a first for Germany, researchers at the Karlsruhe Institute of Technology (KIT) have shown how tin vacancies in diamonds can be precisely controlled using microwaves. These vacancies have special optical and magnetic properties and can be used as qubits, the smallest computational units for quantum computing and quantum communication. The results are an important step for the development of high-performance quantum computers and secure quantum communications networks.
Researchers from Berkeley Lab’s Accelerator Technology & Applied Physics (ATAP) Division have teamed up with colleagues from Michigan State University’s Facility for Rare Isotope Beams (FRIB), the world’s most powerful heavy-ion accelerator, to develop a new superconducting magnet based on niobium-tin (Nb3Sn) technology.
A group of international researchers utilized the advanced underwater technology from MBARI to explore and record the changes in underwater landscapes in a remote Arctic region, focusing on the effects of melting permafrost and the formation of new ice.
Researchers from Monterey Bay Aquarium Research Institute (MBARI), in collaboration with an international team, have discovered extensive underwater ice formations along the edge of the Canadian Beaufort Sea, in a remote Arctic region. This finding uncovers a previously unknown process contributing to the continued formation of submarine permafrost ice.
In a previous MBARI study, researchers observed enormous craters on the seafloor in this area, attributed to the thawing of ancient permafrost submerged underwater. While exploring the flanks of these craters on a subsequent expedition, MBARI researchers and collaborators from the Korea Polar Research Institute (KOPRI), the Korea Institute of Geoscience and Mineral Resources, the Geological Survey of Canada, and the U.S. Naval Research Laboratory observed exposed layers of submarine permafrost ice.
