Phys.org December 20, 2024 Although porous structures should favor colonization by microorganisms, they have not yet been exploited as abiotic scaffolds for the development of living materials. Researchers in Switzerland developed porous ceramics that are colonized by bacteria to form an engineered living material with self-regulated and genetically programmable carbon capture and gas-sensing functionalities. The carbon capture capability was achieved using wild-type photosynthetic cyanobacteria, whereas the gas-sensing function was generated utilizing genetically engineered E. coli. Hierarchical porous clay was used as a ceramic scaffold and evaluated in terms of bacterial growth, water uptake, and mechanical properties. Using state-of-the-art chemical analysis […]
Tag Archives: S&T Switzerland
Machine learning speeds up prediction of materials’ spectral properties
Phys.org December 23, 2024 Koopmans spectral functionals enable the prediction of spectral properties with state-of-the-art accuracy which relies on capturing the effects of electronic screening through scalar, orbital-dependent parameters. The parameters must be computed for every calculation, making Koopmans spectral functionals more expensive. Researchers in Switzerland developed a machine-learning model that can predict these screening parameters directly from orbital densities calculated at the density-functional theory (DFT) level. In two cases they showed that using the screening parameters predicted by this mode led to orbital energies that differ by less than 20 meV on average. This approach substantially reduced the run time […]
Wind alters snow crystals, impacting climate models
Phys.org December 16, 2024 Loose surface snow gets eroded and transported by wind, which influences the snow particles’ physical properties that determine the characteristics of the emerging wind-impacted snowpack layer. Researchers in Switzerland used cold-laboratory ring wind tunnel experiments to study the governing processes during airborne snow transport with stable water isotopes as tracers for these micro-scale processes. They documented the growing and rounding of snow particles with transport time, with a concurrent decrease in specific surface area and attributed this evolution to the process of airborne snow metamorphism. The changes showed a clear isotopic signature of metamorphic deposition, which […]
Infrared detectors made from quantum dots
Nanowerk December 3, 2024 Although hybrid graphene-colloidal PbS quantum dots (QDs) phototransistors are promising to overcome the geometrical restrictions of photodetectors to flat substrates, the experimental demonstration of their application to curved surfaces remains elusive. Researchers in Switzerland demonstrated the seamless integration of an infrared photodetector to a polymer optical fiber (POF), by wrapping graphene around the POF of 1 mm in diameter and, inkjet printing of PbS QDs onto the curved surface. The device acted as a functional coating and detected infrared light propagating through the POF without interrupting the waveguide. The ink supported drop-on-demand, and was colloidally stable […]
Researchers make sound waves travel in one direction only, with implications for electromagnetic wave technology
Phys.org September 6, 2024 Breaking the reciprocity of wave propagation is a problem of fundamental interest, and a much-sought functionality in practical applications, both in photonics and phononics. Although it has been achieved using resonant linear scattering from cavities with broken time-reversal symmetry, such realizations have remained inescapably plagued by inherent passivity constraints, which make absorption losses unavoidable, leading to stringent limitations in transmitted power. Researchers in Switzerland solved this problem by converting the cavity resonance into a limit cycle, exploiting the uncharted interplay between non-linearity, gain, and non-reciprocity. Strong enough incident waves could synchronize with these self-sustained oscillations and […]
High-selectivity graphene membranes enhance COâ‚‚ capture efficiency
Phys.org July 6, 2024 Although membranes based on a porous two-dimensional selective layer offer the potential to achieve exceptional performance to improve energy efficiency and reduce the cost for carbon capture, competitive sorption of CO2 with the potential to yield high permeance and selectivity has remained elusive. Researchers in Switzerland showed that a simple exposure of ammonia to oxidized single-layer graphene at room temperature incorporates pyridinic nitrogen at the pore edges. This led to a highly competitive but quantitatively reversible binding of CO2 with the pore. A combination of CO2/N2 separation factor and CO2 permeance from a stream containing 20 vol% […]
An alternative way to manipulate quantum states
EurekAlert July 2, 2024 Control over quantum systems is typically achieved by time-dependent electric or magnetic fields. Alternatively, electronic spins can be controlled by spin-polarized currents. Researchers in Switzerland demonstrated coherent driving of a single spin by a radiofrequency spin-polarized current injected from the tip of a scanning tunneling microscope into an organic molecule. With the excitation of electron paramagnetic resonance, they established dynamic control of single spins by spin torque using a local electric current. Their work highlighted the dissipative action of the spin-transfer torque, in contrast to the nondissipative action of the magnetic field, which allowed for the […]
Exploring just how extreme future storms could get
Phys.org September 18, 2023 Due to the lack of long homogenous climate data and methodological frameworks, it is challenging to estimate how extreme precipitation could get and what the physical drivers are. Researchers in Switzerland developed two complementary strategies to extrapolate beyond the precipitation records: (a) statistical estimates based on fitting generalized extreme value distributions, providing their probabilistic information on return periods and, (b) ensemble boosting, a model-based re-initialization of heavy precipitation in large ensembles, providing a physical coherent storyline in space and time, however, with no direct quantification of its probability. Both show that 3-day accumulated precipitation maxima can […]
Thin-film batteries rechargeable in just one minute
Science Daily August 29, 2023 The power capability of Li-ion batteries has become increasingly limiting for the electrification of transport on land and in the air. The specific power of Li-ion batteries is restricted due to the required cathode thickness of a few tens of micrometers. Researchers in Switzerland have developed a design of monolithically stacked thin-film cells that had the potential to increase the power ten-fold. They demonstrated an experimental proof-of-concept consisting of two monolithically stacked thin-film cells. Each cell consisted of a silicon anode, a solid-oxide electrolyte, and a lithium cobalt oxide cathode. The battery could be cycled […]
Chromium replaces rare and expensive noble metals
Science Daily August 14, 2023 Researchers in Switzerland developed chromium compounds, very similar to those used in the past, that can replace the noble metals osmium and ruthenium. When irradiated with a red lamp the new chromium compounds the energy from the light could be stored in molecules which could serve as power source. They demonstrated it by building the chromium compounds into a stiff organic molecular framework consisting of carbon, nitrogen, and hydrogen. The stiff framework ensured that the chromium atoms were well packaged. The tailor-made environment minimized energy losses due to undesired molecular vibrations and to optimize the […]