Phys.org September 24, 2024 The causes for the rapid rise of atmospheric methane concentrations over the past decade have been unclear. An international team of researchers (USA – Harvard University, Jet Propulsion Laboratory, UK) found that emissions from the wet tropics drove the 2010–2019 increase and the subsequent 2020–2022 surge, while emissions from northern mid-latitudes decreased. The 2020–2022 surge was principally contributed by emissions in Equatorial Asia and Africa. Wetlands were the major drivers of the 2020–2022 emission increases in Africa and Equatorial Asia because of tropical inundation associated with La Niña conditions, consistent with trends in the GRACE terrestrial […]
Climate models predict abrupt intensification of northern wildfires due to permafrost thawing
Phys.org September 24, 2024 Climate change will accelerate Arctic-Subarctic permafrost thaw which can intensify microbial degradation of carbon-rich soils, methane emissions, and global warming. To better understand the impact of permafrost thaw on future Arctic-Subarctic wildfires and the associated release of greenhouse gases and aerosols an international team of researchers (South Korea, Japan, Norway, USA – National Center for Atmospheric Research, University of Colorado) presented a comprehensive analysis of the effect of future permafrost thaw on land surface processes in the Arctic-Subarctic region using large ensemble forced by the SSP3-7.0 greenhouse gas emission scenario. Analyzing 50 greenhouse warming simulations, which […]
Engineers 3D print sturdy glass bricks for building structures
MIT News September 24, 2024 There is minimal research on the additive manufacturing (AM) viability to produce structural building components, which could reduce tooling costs and increase flexibility for their production. A team of researchers in the US (MIT, industry) has provided design, manufacturing, and experimental testing to assess the feasibility of using glass AM to produce interlocking masonry units for the construction industry. Their glass 3D printer could print a maximum volume for producing full-size masonry units. They discussed how to adapt design guidelines for glass AM to produce interlocking units, evaluated fabrication ease and structural performance using three […]
Extinct volcanoes a ‘rich’ source of rare earth elements, research suggests
Phys.org September 24, 2024 Iron oxide-apatite (IOA) deposits have substantial rare earth elements potential, but their rare earth element (REE) enrichment mechanisms remain uncertain. An international team of researchers (Australia, China) used novel layered piston-cylinder experiments to address these questions. Seventeen magmatic FeP–Si immiscibility experiments, across 800–1150 °C, and at 0.4 and 0.8 GPa, reproduced many natural textural and geochemical features of IOA deposits. Magmatic-hydrothermal fluid bubbles and iron oxide-bubble pairs also formed. The results strongly supported FeP–Si immiscibility as a controlling factor in IOA deposits, although not mutually exclusive with other models. Light REE partition into FeP liquids, preferentially […]
First liquid-liquid extraction trial finds porous liquids can separate harmful or unwanted alcohols from mixtures
Phys.org September 18, 2024 Researchers in the UK explored the application of porous liquids for the separation of miscible liquids, using MEG/water (MEG=monoethylene glycol) and EtOH/water as proof-of-principle. PLs ZIF-8@PDMS (PL1, PDMS=polydimethylsilicone) or ZIF-8@sesame oil (PL2) each consisting of 25 wt % of the hydrophobic microporous material ZIF-8 was dispersed in PDMS or sesame oil respectively were physically stable to sedimentation. MEG was selectively extracted through a membrane from approximately into the PL phase. The PL could also be regenerated and re-used, suggesting its potential for continuous, cyclic extraction, PL3 (silicalite-1@PDMS) was effective in selective alcohol extraction from beverages. According to […]
High-pressure reactions can turn nonporous rocks into sponges
Phys.org September 23, 2023 An international team of researchers (Switzerland, France, Germany) studied (de)hydration reactions where associated solid density changes were predominantly balanced by porosity changes, with solid rock deformation playing a minor role and proposed a hypothesis for three scenarios of (de)hydration front propagation and test it. The models coupled porous fluid flow, solid rock volumetric deformation, and (de)hydration reactions. Their model validated the hypothesized scenarios and showed that the change in solid density across the reaction boundary dictates whether hydration or dehydration fronts propagate. The models demonstrated that reactions could drive the propagation of (de)hydration fronts, characterized by […]
The importance of wave modeling in predicting climate change’s effect on sea ice
Phys.org September 24, 2024 Researchers in Australia used a theoretical model to study water waves propagating into and through a region containing thin floating ice, for ice covers transitioning from consolidated (large floe sizes) to fully broken (small floe sizes). The degree of breaking was simulated by a mean floe length. The model predicted deterministic limits for consolidated and fully broken ice covers where the wave fields do not depend on the realization of the ice cover for a given mean floe length. The consolidated ice limit was consistent with classic flexural-gravity wave theory, and the fully broken limit was […]
Light momentum turns pure silicon from an indirect to a direct bandgap semiconductor
Phys.org September 20, 2024 Photons do not carry sufficient momentum to induce indirect optical transitions in semiconducting materials, such as silicon, necessitating the assistance of lattice phonons to conserve momentum. Therefore, silicon is a less attractive material for a wide variety of optoelectronic applications. An international team of ranchers (Russia, Israel, USA – UC Irvine) introduced an alternative strategy to fulfill the momentum-matching requirement in indirect optical transitions. They demonstrated that when confined to scales below ∼3 nm, photons acquired sufficient momentum to allow electronic transitions at the band edge of Si without the assistance of a phonon. Confined photons […]
New material with wavy layers of atoms exhibits unusual superconducting properties
Phys.org September 19, 2024 Bulk van der Waals (vdW) superlattices hosting 2D interfaces between minimally disordered layers represent scalable bulk analogues of artificial vdW heterostructures and present a complementary venue to explore incommensurately modulated 2D states. An international team of researchers in the (USA- MIT, National High Magnetic Field Laboratory, Harvard, Japan) reported the bulk vdW superlattice SrTa2S5 realizing an incommensurate one-dimensional (1D) structural modulation of 2D transition metal dichalcogenide (TMD) H-TaS2 layers. High-quality electronic transport in the H-TaS2 layers was made anisotropic by the modulation and exhibited commensurability oscillations paralleling lithographically modulated 2D systems. They found unconventional, clean-limit superconductivity […]
Novel computational method addresses obstacles in phonon-based heat simulation
Phys.org September 23, 2024 The phonon Boltzmann transport equation (BTE) is commonly used for qualitatively studying the non-Fourier thermal transport phenomena of toy problems. Researchers at the University of Michigan demonstrated an efficient and parameter-free computational method of the phonon BTE to achieve quantitatively accurate thermal simulation for realistic materials and devices. Their method did not rely on empirical material properties input. It could be generally applicable for different materials and the predicted results could match well with experimental results. According to the researchers full-scale thermal simulation of a 3-dimensional fin field-effect transistor with 13 million degrees of freedom, could […]