China's Chang'e-4 probe marked the first soft-landing of a spacecraft on the far side of the Moon, which always faces away from Earth. To communicate with ground stations, Chang'e-4 relies on Queqiao, a relay communication satellite that orbits a point behind the Moon and bridges Earth and Chang'e-4. In a recent review, researchers explain the design of Queqiao and depict the future of lunar relay communication systems.
Researchers from Skoltech have designed and conducted experiments measuring gas permeability under various conditions for ice-containing sediments mimicking permafrost. Their results can be useful both in tracing methane emission in high latitudes and in modeling and testing techniques for gas production from Arctic reservoirs. The study also showed that the dissociation of gas hydrates can lead to permeability increase. This, in turn, will lead to methane emissions into the atmosphere, causing a variety of environmental and technological impacts.
Acoustic waves in gases, liquids, and solids usually travel at an almost constant speed of sound. Rotons are an exception: their speed of sound changes significantly with the wavelength, it is also possible that the waves travel backwards. Researchers at Karlsruhe Institute of Technology are studying the possibilities of using rotons in artificial materials. These metamaterials might be used in the future to manipulate or direct sound in ways that have never been possible before.
Researchers from Lawrence Berkeley National Laboratory and Fathom Bristol used a hydraulic model to consider the degree to which human-caused climate change may have affected flooding in Houston in 2017 during Hurricane Harvey. Resources at the National Energy Research Scientific Computing Center were used to quantify the increase in Houston flood area and depth and to host a portal where other scientists and the public can access and explore the resulting data.
Financial institutions are linked together in a global web of interactions whose structure can be analyzed quantitatively by means of network theory. Today, 15 years after the 2007-2008 financial crisis, the role of networks for monitoring financial stability is widely recognized. Both policymakers and researchers agree that systemic risk has to be studied and managed by adopting a network perspective.
The COVID-19 pandemic has made clear the importance of understanding precisely how diseases spread throughout networks of transportation. In a paper publishing on Thursday in the IAM Journal on Applied Mathematics, Stephen Kirkland (University of Manitoba), Zhisheng Shuai (University of Central Florida), P. van den Driessche (University of Victoria), and Xueying Wang (Washington State University) study the way in which changes in a network of multiple interconnected communities impact the ensuing spread of disease.
Researchers from York University and the University of British Columbia have found social media use to be one of the factors related to the spread of COVID-19 within dozens of countries during the early stages of the pandemic. The researchers say this finding resembles other examples of social media misinformation ranging from the initial phase of vaccine rollout to the 2021 Capitol riot in the United States.
Organic photovoltaics max out at 15%-20% efficiency. Lehigh University researchers are using physics-informed machine learning to improve this efficiency. Their findings suggest a machine learning model, trained on coarse grained molecular models, can identify the optimal parameters for manufacturing in much less time than traditional methods. The researchers are currently exploring alternative materials for solar cells and will use their machine learning framework to optimize the production of such materials.
Scientists from the Immanuel Kant Baltic Federal University with foreign colleagues have developed a method that allows not only to predict the appearance of glitches but even to eliminate their influence on experiments.
Trends in heat discomfort are more subtle than expected across Saudi Arabia and beyond.