Phys.org November 19, 2024 The renewable energy industry is heavily reliant on rare earth elements. A team of researchers in the US (UT Austin, University of Kentucky, University of Wyoming, industry) estimated coal ash resources and potential for extraction of rare earth elements using data for the US. According to the data ~ 52 gigatons (Gt) of coal was produced in the US (1950–2021). Power plants account for most of the coal use. About 70% of coal ash was potentially accessible for rare earth element extraction (1985–2021) and was disposed in landfills and ponds with the remaining coal ash was used […]
Generative AI Meets Open-Ended Survey Responses: Participant Use of AI and Homogenization
Phys.org November 25, 2024 Generative AI tools present new challenges for data quality in online surveys and experiments. A team of researchers in the US (New York University, Stanford University, Cornell University) examined participants’ use of large language models to answer open-ended survey questions and described empirical tendencies in human vs LLM-generated text responses. From social science research participants, 34%, reported using LLMs to help them answer open-ended survey questions. Researchers found that LLM responses are more homogeneous and positive. According to the researchers homogenization patterns may mask important underlying social variation in attitudes and beliefs among human subjects, raising […]
Making a difference: Efficient water harvesting from air possible
Eurekalert November 27, 2024 Liquid moisture adsorbents recover water from the atmosphere and used in applications such as atmospheric water harvesting (AWH) and desiccant air conditioning (DAC), allow for flexible device design as well as lower regeneration temperatures. Desorption performance of liquid adsorbents has been less studied. Previously, researchers in Japan combined oligomeric poly(ethylene glycol) (PEG) and oligomeric poly(propylene glycol) (PPG), resulting in a lowered water desorption temperature and enhanced water desorption efficiency, which was facilitated by a “hydrophilicity-difference-induced water transfer (HWT)” mechanism. Now in their study the researchers investigated PEG-PPG copolymer combinations with PEG for enhancing HWT. The results […]
Nanoink and printing technologies could enable electronics repairs, production in space
Phys.org November 21, 2024 Commercially available inks designed and optimized for Electrohydrodynamic (EHD) are currently very limited. A team of researchers in the US (Iowa State University, University of Wisconsin – Madison) developed a new silver nanoink platform by synthesizing silver nanoparticles in situ with biobased polymer 2-hydroxyethyl cellulose (HEC). This approach significantly outperformed the traditional use of polyvinylpyrrolidone (PVP). The synthesized nanoinks produced precise, high-resolution features by EHD printing with smooth lines narrower than 5 μm. They developed a semiempirical model to reveal the relationship between printing resolution, ink properties, and printing parameters, enabling precise printing control, demonstrated its […]
Oceans emit sulfur and cool the climate more than previously thought
Phys.org November 27, 2024 Ocean-emitted dimethyl sulfide (DMS) is a major source of climate-cooling aerosols. However, most of the marine biogenic sulfur cycling is not routed to DMS but to methanethiol (MeSH), another volatile whose reactivity has hitherto hampered measurements. An international team of researchers (Spain, Argentina, China, USA – Old Dominion University, France) compiled a database of seawater MeSH concentrations, identified their statistical predictors, and produced monthly fields of global marine MeSH emissions adding to DMS emissions. Implemented into a global chemistry-climate model, MeSH emissions increased the sulfate aerosol burden by 30 to 70% over the Southern Ocean and […]
A pathway towards new quantum devices: Electrically defined quantum dots in zinc oxide
Nanowerk November 26, 2024 Quantum devices such as spin qubits have been extensively investigated in electrostatically confined quantum dots using high-quality semiconductor heterostructures like GaAs and Si. Researchers in Japan demonstrated electrostatically forming the quantum dots in ZnO heterostructures. They uncovered the distinctive signature of the Kondo effect independent of the even-odd electron number parity, which contrasts with the typical behavior of the Kondo effect in GaAs. By analyzing temperature and magnetic field dependences, they found that the absence of the even-odd parity in the Kondo effect was not straightforwardly interpreted by the considerations developed for conventional semiconductors. Based on […]
Quantum-inspired design boosts efficiency of heat-to-electricity conversion
Phys.org November 21, 2024 Thermophotovoltaics (TPV) is promising for thermal storage and generation. TPV systems employing selective thermal emitters allow compact designs for various terrestrial and space applications, but these systems have low efficiency. The selective thermal emitter and the low-bandgap photovoltaic cell contribute to this problem. Researchers at Rice University solved the shortcomings of the thermal emitter by using a novel approach based on non-Hermitian optics. They demonstrated a hybrid metal-dielectric non-Hermitian selective emitter (NHE) with high spectral efficiency and employed the NHE in a TPV system operating at 1273 K. They showed that a maximum TPV conversion efficiency of […]
Scientists develop novel high-fidelity quantum computing gate
Phys.org November 22, 2024 Striving for higher gate fidelity is crucial not only for enhancing existing noisy intermediate-scale quantum devices, but also for unleashing the potential of fault-tolerant quantum computation through quantum error correction. Researchers in Japan proposed theoretical scheme, the double-transmon coupler (DTC), that aims to achieve both suppressed residual interaction and a fast high-fidelity two-qubit gate simultaneously, particularly for highly detuned qubits. The state-of-the-art fabrication techniques and a model-free pulse-optimization process would enable not only efficient fault-tolerant quantum computing with error correction but also effectively mitigate errors in current noisy intermediate-scale quantum devices. According to the researchers the […]
Tunable ultrasound propagation in microscale metamaterials
MIT News November 20, 2024 Challenges in miniaturizing and characterizing acoustic metamaterials in high-frequency (megahertz) regimes have hindered progress toward experimentally implementing ultrasonic-wave control. A team of researchers in the US (MIT, Kansas City National Security Campus) presented an inertia design framework based on positioning microspheres to tune responses of 3D microscale metamaterials. They demonstrated tunable quasi-static stiffness by up to 75% and dynamic longitudinal-wave velocities by up to 25% while maintaining identical material density. The researchers explored the tunable static and elastodynamic property relation. According to the researchers their design framework expands the quasi-static and dynamic metamaterial property space […]
Twisted light gives electrons a spinning kick: Researchers develop a novel way to control quantum interactions
Phys.org November 26, 2024 A fundamental requirement for quantum technologies is the ability to coherently control the interaction between electrons and photons. However, in many scenarios involving the interaction between light and matter, the exchange of linear or angular momentum between electrons and photons is not feasible, due to the dipole approximation limit. An international team of researchers (USA – University of Maryland, Italy, Spain, Germany, Japan, Australia) conceived a mechanism for such an orbital angular momentum transfer from optical vortex beams to electronic quantum Hall states. They identified a robust contribution to the radial photocurrent, in an annular graphene […]