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Category: chemistry – Page 280

A long-held goal by chemists across many industries, including energy, pharmaceuticals, energetics, food additives and organic semiconductors, is to imagine the chemical structure of a new molecule and be able to predict how it will function for a desired application. In practice, this vision is difficult, often requiring extensive laboratory work to synthesize, isolate, purify and characterize newly designed molecules to obtain the desired information.

Recently, a team of Lawrence Livermore National Laboratory (LLNL) materials and computer scientists have brought this vision to fruition for energetic molecules by creating machine learning (ML) models that can predict molecules’ crystalline properties from their alone, such as molecular density. Predicting crystal structure descriptors (rather than the entire crystal structure) offers an efficient method to infer a material’s properties, thus expediting materials design and discovery. The research appears in the Journal of Chemical Information and Modeling.

“One of the team’s most prominent ML models is capable of predicting the crystalline density of energetic and energetic-like molecules with a high degree of accuracy compared to previous ML-based methods,” said Phan Nguyen, LLNL applied mathematician and co-first author of the paper.

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The US Defense Advanced Research Projects Agency (DARPA) has recently commissioned three private companies, Blue Origin, Lockheed Martin and General Atomics, to develop nuclear fission thermal rockets for use in lunar orbit.

Such a development, if flown, could usher in a new era of spaceflight. That said, it is only one of several exciting avenues in rocket propulsion. Here are some others.

The standard means of propulsion for spacecraft uses chemical rockets. There are two main types: solid-fueled (such as the solid rocket boosters on the Space Shuttle), and liquid-fueled (such as the Saturn V).

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In a decade-long quest, scientists at Berkeley Lab, the University of Hawaii, and Florida International University uncover new clues to the origins of the universe – and land new chemistry for cleaner combustion engines.

For nearly half a century, astrophysicists and organic chemists have been on the hunt for the origins of C6H6, the benzene ring – an elegant, hexagonal molecule comprised of 6 carbon and 6 hydrogen atoms.

Astrophysicists say that the benzene ring could be the fundamental building block of polycyclic aromatic hydrocarbons or PAHs, the most basic materials formed from the explosion of dying, carbon-rich stars. That swirling mass of matter would eventually give shape to the earliest forms of carbon – precursors to molecules some scientists say are connected to the synthesis of the earliest forms of life on Earth.

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A free-floating planet (FFP) is a planetary-mass object that orbits around a non-stellar massive object (e.g. a brown dwarf) or around the Galactic Centre. The presence of exomoons orbiting FFPs has been theoretically predicted by several models. Under specific conditions, these moons are able to retain an atmosphere capable of ensuring the long-term thermal stability of liquid water on their surface. We model this environment with a one-dimensional radiative-convective code coupled to a gas-phase chemical network including cosmic rays and ion-neutral reactions. We find that, under specific conditions and assuming stable orbital parameters over time, liquid water can be formed on the surface of the exomoon. The final amount of water for an Earth-mass exomoon is smaller than the amount of water in Earth oceans, but enough to host the potential development of primordial life.

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Using the full system, farmers could reduce costs by 40% and chemical usage by up to 95%.

Small Robot Company (SRC), a British agritech startup for sustainable farming, has developed AI-enabled robots – named Tom, Dick and Harry – that identify and kill individual weeds with electricity. These agricultural robots could reduce the use of harmful chemicals and heavy machinery, paving the way for a new approach to sustainable crop farming.

The startup has been working on automated weed killers since 2017, and this April officially launched Tom, the first commercial robot currently operating on three UK farms. Dick is still in the prototype phase, and Harry is still in development.

Small Robot company says the robot Tom is capable of scanning around 20 Hectares per day, collecting about six terabytes of data in an 8-hour shift to identify the crops, spots undesirable weeds – using “Wilma,” an artificial intelligence operating system. This data can then be sent to Dick – the world’s first non-chemical robotic weeding system that zaps individual weeds with electrical ‘lightning strikes.’ And finally, Harry plants seeds in the weed-free soil.

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For tens of thousands of years, a microscopic creature lay frozen and immobile underground in the Siberian permafrost.

Yet, when scientists thawed it out, the tiny multicellular animal didn’t just revive — it reproduced, suggesting that there is a mechanism whereby multicellular animals can avoid cell damage during the freezing process and wake up ready to rumble.

“Our report is the hardest proof as of today that multicellular animals could withstand tens of thousands of years in cryptobiosis, the state of almost completely arrested metabolism,” said biologist Stas Malavin of the Soil Cryology Laboratory at the Institute of Physicochemical and Biological Problems in Soil Science in Russia.

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Researchers from Cornell University’s School of Applied and Engineering Physics and Samsung’s Advanced Institute of Technology have created a first-of-its-kind metalens—a metamaterial lens—that can be focused using voltage instead of mechanically moving its components.

The proof of concept opens the door to a range of compact varifocal lenses for possible use in many imaging applications such as satellites, telescopes and microscopes, which traditionally focus light using curved lenses that adjust using mechanical parts. In some applications, moving traditional glass or plastic lenses to vary the focal distance is simply not practical due to space, weight or size considerations.

Metalenses are flat arrays of nano-antennas or resonators, less than a micron thick, that act as focusing devices. But until now, once a metalens was fabricated, its was hard to change, according to Melissa Bosch, doctoral student and first author of a paper detailing the research in the American Chemical Society’s journal Nano Letters.

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