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Archive for the ‘chemistry’ category: Page 226

Nov 16, 2021

Element selection for crystalline inorganic solid discovery guided by unsupervised machine learning of experimentally explored chemistry

Posted by in categories: chemistry, robotics/AI, space

Machine learning (ML) models are powerful tools to study multivariate correlations that exist within large datasets but are hard for humans to identify16,23. Our aim is to build a model that captures the chemical interactions between the element combinations that afford reported crystalline inorganic materials, noting that the aim of such models is efficacy rather than interpretability, and that as such they can be complementary guides to human experts. The model should assist expert prioritization between the promising element combinations by ranking them quantitatively. Researchers have practically understood how to identify new chemistries based on element combinations for phase-field exploration, but not at significant scale. However, the prioritization of these attractive knowledge-based choices for experimental and computational investigation is critical as it determines substantial resource commitment. The collaborative ML workflow24,25 developed here includes a ML tool trained across all available data at a scale beyond that, which humans can assimilate simultaneously to provide numerical ranking of the likelihood of identifying new phases in the selected chemistries. We illustrate the predictive power of ML in this workflow in the discovery of a new solid-state Li-ion conductor from unexplored quaternary phase fields with two anions. To train a model to assist prioritization of these candidate phase fields, we extracted 2021 MxM yAzA t phases reported in ICSD (Fig. 1, Step 1), and associated each phase with the phase fields M-M ′-A-A′ where M, M ′ span all cations, A, A ′ are anions {N3−, P3−, As3−, O2−, S2−, Se2−, Te2−, F, Cl, Br, and I} and x, y, z, t denote concentrations (Fig. 1, Step 2). Data were augmented by 24-fold elemental permutations to enhance learning and prevent overfitting (Supplementary Fig. 2).

ML models rely on using appropriate features (often called descriptors)26 to describe the data presented, so feature selection is critical to the quality of the model. The challenge of selecting the best set of features among the multitude available for the chemical elements (e.g., atomic weight, valence, ionic radius, etc.)26 lies in balancing competing considerations: a small number of features usually makes learning more robust, while limiting the predictive power of resulting models, large numbers of features tend to make models more descriptive and discriminating while increasing the risk of overfitting. We evaluated 40 individual features26,27 (Supplementary Fig. 4, 5) that have reported values for all elements and identify a set of 37 elemental features that best balance these considerations. We thus describe each phase field of four elements as a vector in a 148-dimensional feature space (37 features × 4 elements = 148 dimensions).

To infer relationships between entries in such a high-dimensional feature space in which the training data are necessarily sparsely distributed28, we employ the variational autoencoder (VAE), an unsupervised neural network-based dimensionality reduction method (Fig. 1, Step 3), which quantifies nonlinear similarities in high-dimensional unlabelled data29 and, in addition to the conventional autoencoder, pays close attention to the distribution of the data features in multidimensional space. A VAE is a two-part neural network, where one part is used to compress (encode) the input vectors into a lower-dimensional (latent) space, and the other to decode vectors in latent space back into the original high-dimensional space. Here we choose to encode the 148-dimensional input feature space into a four-dimensional latent feature space (Supplementary Methods).

Nov 16, 2021

New algorithms advance the computing power of early-stage quantum computers

Posted by in categories: chemistry, computing, information science, quantum physics

A group of scientists at the U.S. Department of Energy’s Ames Laboratory has developed computational quantum algorithms that are capable of efficient and highly accurate simulations of static and dynamic properties of quantum systems. The algorithms are valuable tools to gain greater insight into the physics and chemistry of complex materials, and they are specifically designed to work on existing and near-future quantum computers.

Scientist Yong-Xin Yao and his research partners at Ames Lab use the power of advanced computers to speed discovery in condensed matter physics, modeling incredibly complex quantum mechanics and how they change over ultra-fast timescales. Current high performance computers can model the properties of very simple, small quantum systems, but larger or more rapidly expand the number of calculations a computer must perform to arrive at an , slowing the pace not only of computation, but also discovery.

“This is a real challenge given the current early-stage of existing quantum computing capabilities,” said Yao, “but it is also a very promising opportunity, since these calculations overwhelm classical computer systems, or take far too long to provide timely answers.”

Nov 15, 2021

Electricity and chemistry could give biofuels a big boost

Posted by in categories: chemistry, sustainability

Scientists found an easier way to produce a chemical reaction important in making biofuels, possibly lowering the cost of biofuel production.

Nov 15, 2021

The Only Artificial Intelligence that can Learn — Deepmind Meta-Learning

Posted by in categories: chemistry, robotics/AI, singularity

Artificial Intelligence’s biggest Problems is their inability to keep on learning after they’ve completed their training. But now, Google’s Deepmind has created a Meta-Learning AI which keeps on learning and improving indefinitely without any Human supervision. Deepmind created the AI Game: Alchemy, which is a chemistry-based game for AI Agents to play and improve in. But Artificial Intelligence improving without limits also puts some concerns into AI researchers focused on deep learning.

There has been rapidly growing interest in meta-learning as a method for increasing the flexibility and sample efficiency of reinforcement learning.

Continue reading “The Only Artificial Intelligence that can Learn — Deepmind Meta-Learning” »

Nov 14, 2021

Scientists Create Artificial Mitochondria That Can Make Energy for Damaged Cells

Posted by in categories: biotech/medical, chemistry, cybercrime/malcode

And it can be hacked.

The authors of a new study in Nature Catalysis reprogrammed these blobs—called exosomes—into an army of living nanobioreactors. It’s a seemingly simple process of mix and match: each blob is filled with a different chemical that’s involved in a biological reaction. By bringing two together, the blobs merge into a single squishy container, allowing the two chemicals to react.

The results were explosive. The tiny bioreactors pumped out energy molecules, called ATP, inside living cells. The burst of energy saved injured cells, providing them with a boost of power to fight back against dangerous molecules that otherwise lead to cell death.

Nov 12, 2021

Newly developed compound may enable sustainable, cost-effective, large-scale energy storage

Posted by in categories: chemistry, energy, engineering, sustainability

To produce a cost-effective redox flow battery, researchers based at the South China University of Technology have synthesized a molecular compound that serves as a low-cost electrolyte, enabling a stable flow battery that retains 99.98% capacity per cycle. They published their approach on August 14 in the Energy Material Advances.

Comprising two tanks of opposing liquid electrolytes, the battery pumps the positive and negative liquids along a membrane separator sandwiched between electrodes, facilitating ion exchanges to produce energy. Significant work has been dedicated to developing the negative electrolyte liquid, while the positive electrolyte liquid has received less attention, according to corresponding author Zhenxing Liang, professor in the Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology.

“Aqueous redox flow batteries can realize the stable electrical output for using unsteady solar and wind energy, and they have been recognized as a promising large-scale energy storage ,” Liang said. “Electroactive organic merit of element abundance, low cost and flexible molecular control over the electrochemical features for both positive and negative electrolytes are regarded as key to developing next-generation redox flow batteries.”

Nov 11, 2021

Self-Driving Farm Robot Uses Lasers To Kill 100,000 Weeds An Hour, Saving Land And Farmers From Toxic Herbicides

Posted by in categories: chemistry, health, robotics/AI, sustainability, transportation

The nutrient content of our vegetables is down 40% over the last two decades and our soil health is suffering due to increasingly harsh herbicide use, according to Carbon Robotics founder Paul Mikesell. And farmers are increasingly concerned about the long-term health impacts of continually spraying chemicals on their fields.

But not weeding will cost half your crop, killing profitability.

The solution?

Nov 11, 2021

Into the Metaverse: Where crypto, gaming and capitalism collide

Posted by in categories: biotech/medical, chemistry, entertainment

To understand why Mark Zuckerberg thinks “the metaverse” is the next frontier, consider the case of Sam Peurifoy. The 27-year-old chemistry PhD from Columbia University left his job at Goldman Sachs at the height of the pandemic and is now seeking out his fortune in crypto by playing video games.

He has recruited dozens of people from Mexico to the Philippines to a “Guild” that plays under the command of “Captain” Peurifoy. In exchange, he ponies up the funds needed to enter Axie Infinity, a game where players collect Smooth Love Potion — a digital token that can potentially be converted into real money.

Nov 11, 2021

Electrochemical pulse method resolves materials joining in solid-state batteries

Posted by in categories: chemistry, mobile phones, sustainability, transportation

Scientists at Oak Ridge National Laboratory (ORNL) have developed a scalable, low-cost electrochemical pulse method to improve the contact between layers of materials in solid-state batteries, resolving one of the big challenges in the commercial development of safe, long-lived energy storage systems. The new technology could pave the way for electric vehicles and smartphones that work much longer with each charge.

One of the challenges in manufacturing solid-state batteries is the difficulty of getting materials to properly join and remain stable during repeated cycles of charging and discharging. This leads to instability in the joints and causes the formation of voids, something known as contact impedance. Applying high pressures is one way to solve this problem, but that process can lead to shorting and would need to be re-applied periodically to extend the battery’s life using an expensive aftermarket application.

ORNL scientists have found that they could eliminate these voids by applying a short, high-voltage electrochemical pulse when joining layers of lithium metal anode material with a solid electrolyte material. These pulses see a current surrounding the lithium metal-encased voids and cause them to dissipate, leading to increased contact at the interface of the materials while resulting in no detrimental effects.

Nov 11, 2021

Tiny bubbles: Researchers develop a flexible new system for creating soft robotics

Posted by in categories: biological, chemistry, robotics/AI

Princeton researchers have invented bubble casting, a new way to make soft robots using “fancy balloons” that change shape in predictable ways when inflated with air.

The new system involves injecting bubbles into a liquid polymer, letting the material solidify and inflating the resulting device to make it bend and move. The researchers used this approach to design and create hands that grip, a fishtail that flaps and slinky-like coils that retrieve a ball. They hope that their simple and versatile method, published Nov. 10 in the journal Nature, will accelerate the development of new types of soft robots.

Traditional rigid robots have multiple uses, such as in manufacturing cars. “But they will not be able to hold your hands and allow you to move somewhere without breaking your wrist,” said Pierre-Thomas Brun, an assistant professor of chemical and and the lead researcher on the study. “They’re not naturally geared to interact with the soft stuff, like humans or tomatoes.”