Physics World April 17, 2020 Using detailed-balance calculations researchers at the University of New York have shown that underwater solar cells can exhibit efficiencies from ∼55% in shallow waters to more than 65% in deep waters, while maintaining a power density >5 mW cm −2. They showed that the optimum band gap of the solar cell shifts by ∼0.6 eV between shallow and deep waters and plateaus at ∼2.1 eV at intermediate depths, independent of geographical location. This wide range in optimum band-gap energies opens the potential for a library of wide-band-gap semiconductors to be used for high-efficiency underwater solar […]
Aquaculture at the crossroads of global warming and antimicrobial resistance
Science Daily April 20, 2020 Fish farmers use large quantities of antimicrobials to treat or prevent disease on their farms. However, when used inappropriately, antimicrobials are ineffective and foster the development of resistant bacteria. An international team of researchers (France, Germany) conducted a double meta-analysis to explore how global warming and antimicrobial resistance impact aquaculture. They calculated a Multi-Antibiotic Resistance index (MAR) of aquaculture-related bacteria for 40 countries. They showed that aquaculture MAR indices correlate with MAR indices from human clinical bacteria, temperature and countries’ climate vulnerability and infected aquatic animals present higher mortalities at warmer temperatures. They raise the […]
A breakthrough in estimating the size of a (mostly hidden) network
Phys.org April 22, 2020 For homogeneous networks accessing a mere 10% of the units could be sufficient to exactly infer the size of the entire network. But the same approach fails for heterogeneous networks, which are far more common in the field of complex systems. Researchers at New York University present a model-free approach to address this problem by studying the rank of a detection matrix that collates sampled time series of perceptible nodes from independent experiments. They unveil a connection between the rank of the detection matrix and the control-theoretic notion of observability. With this information it is to […]
Drones Use Radio Waves to Recharge Sensors While in Flight
IEEE Spectrum April 17, 2020 An international team of researchers (Lebanon, Italy) has developed and implemented a RF energy harvesting and wake-up system that scavenges a 2.4 GHz signal from a UAV. It can deliver power wirelessly to remote sensors. The signal transmitted by the UAV is harvested and rectified to DC voltage to power a sensor on the ground. Additionally, the UAV modulates the transmitted signal to encode an address that triggers a particular sensor from sleep mode to active mode. Charging can be initiated from input power levels as low as -18.2~dBm and a sensor can be triggered […]
Electrical manipulation of magnetic particle allows for large high-speed memory
Phys.org April 20, 2020 Antiferromagnetic materials seem harder to work with but have many useful properties and they are less subject to external magnetic fields due to a unique arrangement of their constituent parts making it harder to manipulate the material as needed. According to researchers in Japan in antiferromagnetic manganese-tin alloy Mn3Sn Weyl fermions exist at Weyl points in momentum space. They have two possible states that could represent binary digits. They found that it is possible to switch a Weyl point between these states with an external electrical current applied to neighboring thin layers of Mn3Sn and either […]
Global AI Agenda
MIT Technology Insights April 22, 2020 This report is part of “The global AI agenda,” a thought leadership program by MIT Technology Review Insights examining how organizations are using AI today and planning to do so in the future. Featuring a global survey of 1,004 AI experts. From China to Japan, Singapore to India, policymakers across Asia have developed national-level plans for how AI can be used to enhance domestic and regional competitiveness, which include public and private sector collaboration. The results of the Asia-Pacific survey underscore the readiness of bringing AI to the fore when it comes down to driving […]
New ‘brick’ for nanotechnology: Graphene Nanomesh
EurekAlert April 20, 2020 Researchers in Japan have demonstrated that large area suspended graphene nanomesh is quickly achievable by the helium ion beam microscopy with sub-10 nm nanopore diameter and well-controlled pitches. Comparing to slow speed TEM patterning, the helium ion beam milling technique overcomes the speed limitation, and meanwhile, provides a high imaging resolution. With the initial electrical measurements, they found that the thermal activation energy of the graphene nanomesh increased exponentially by increasing the porosity of the graphene nanomesh. This immediately provides a new method for bandgap engineering beyond the conventional nanoribbon method. The research provides a practical […]
Pentagon awards contracts to design mobile nuclear reactor
Defense News March 9, 2020 Project Pele is run through the Strategic Capabilities Office within DDR&E of DOD, involves the development of a safe, mobile and advanced nuclear microreactor to support a variety of Department of Defense missions such as generating power for remote operating bases. Under the program the Pentagon issued three contracts to start design work as part of a two-step plan. The system should be safely and rapidly moveable by road, rail, sea, or air and quick to set up and shut down, with a design which is inherently safe. If the testing goes well, a commercially […]
Photonic microwave generation using on-chip optical frequency combs
Science Daily April 20, 2020 Soliton microcombs can now be built using CMOS-compatible photonic integrated circuits. However, they operate with repetition rates significantly beyond those that conventional electronics can detect, preventing their use in microwave photonics. Researchers in Switzerland have demonstrated soliton microcombs operating in two widely employed microwave bands, the X-band (~10 GHz, for radar) and the K-band (~20 GHz, for 5G). Driven by a low noise fibre laser, these devices produce more than 300 frequency lines within the 3 dB bandwidth, and generate microwave signals with phase noise levels comparable to modern electronic microwave oscillators. The results establish integrated microcombs as […]
Quantum entanglement offers unprecedented precision for GPS, imaging and beyond
Science Daily April 20, 2020 To date, almost all quantum-metrology demonstrations are restricted to improving the measurement performance at a single sensor. A team of researchers in the US (University of Arizona, industry) has demonstrated an entangled sensor network, empowered by continuous-variable (CV) multipartite entanglement, which is composed of three sensor nodes each equipped with an electro-optic transducer for the detection of radio-frequency (RF) signals. By properly tailoring the CV multipartite entangled states, the network can be reconfigured to maximize the quantum advantage in distributed RF sensing problems such as measuring the angle of arrival of an RF field. The […]