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Category: chemistry – Page 10

Monte Carlo method

Monte Carlo methods, or Monte Carlo experiments, are a broad class of computational algorithms that rely on repeated random sampling to obtain numerical results. The underlying concept is to use randomness to solve problems that might be deterministic in principle. The name comes from the Monte Carlo Casino in Monaco, where the primary developer of the method, mathematician Stanisław Ulam, was inspired by his uncle’s gambling habits.

Monte Carlo methods are mainly used in three distinct problem classes: optimization, numerical integration, and generating draws from a probability distribution. They can also be used to model phenomena with significant uncertainty in inputs, such as calculating the risk of a nuclear power plant failure. Monte Carlo methods are often implemented using computer simulations, and they can provide approximate solutions to problems that are otherwise intractable or too complex to analyze mathematically.

Monte Carlo methods are widely used in various fields of science, engineering, and mathematics, such as physics, chemistry, biology, statistics, artificial intelligence, finance, and cryptography. They have also been applied to social sciences, such as sociology, psychology, and political science. Monte Carlo methods have been recognized as one of the most important and influential ideas of the 20th century, and they have enabled many scientific and technological breakthroughs.

Assembly instructions for enzymes: Universal rules can help to design an optimal enzyme from scratch

In biology, enzymes have evolved over millions of years to drive chemical reactions. Scientists from the Max Planck Institute for Dynamics and Self-Organization (MPI-DS) have now derived universal rules to enable the de novo design of optimal enzymes.

The paper is published in the journal Chem Catalysis.

As an example, they considered the of breaking a dimer into two monomer molecules. Considering the geometry of such an enzyme-substrate-complex, they identified three golden rules that should be considered to build a functional enzyme.

Lockheed uses IBM quantum processor to solve major chemistry puzzle

Researchers at IBM and Lockheed Martin teamed up high-performance computing with quantum computing to accurately model the electronic structure of ‘open-shell’ molecules, methylene, which has been a hurdle with classic computing over the years. This is the first demonstration of the sample-based quantum diagonalization (SQD) technique to open-shell systems, a press release said.

Quantum computing, which promises computations at speeds unimaginable by even the fastest supercomputers of today, is the next frontier of computing. Leveraging quantum states of molecules to serve as quantum bits, these computers supersede computational capabilities that humanity has had access to in the past and open up new research areas.

A new approach could fractionate crude oil using much less energy

Separating crude oil into products such as gasoline, diesel, and heating oil is an energy-intensive process that accounts for about 6% of the world’s CO2 emissions. Most of that energy goes into the heat needed to separate the components by their boiling point.

In an advance that could dramatically reduce the amount of energy needed for fractionation, MIT engineers have developed a that filters the components of crude oil by their molecular size.

“This is a whole new way of envisioning a separation process. Instead of boiling mixtures to purify them, why not separate components based on shape and size? The key innovation is that the filters we developed can separate very at an atomistic length scale,” says Zachary P. Smith, an associate professor of chemical engineering at MIT and the senior author of the new study.

Hopes for alien life dim as doubts emerge over exoplanet K2-18b chemical signals

When astronomers announced last month they might have discovered the most promising hints of alien life yet on a distant planet, the rare good news raised hopes humanity could soon learn we are not alone in the universe.

But several recent studies looking into the same data have found that there is not enough evidence to support such lofty claims, with one scientist accusing the astronomers of “jumping the gun.”

The debate revolves around the planet K2-18b, which is 124 away in the Leo constellation.

Advancements in (Ca, Ba)ZrS₃ solar cells using innovative spinel hole transport layers

Solar power has long been a beacon of hope in our pursuit of clean energy. However, the road to sustainable, high-efficiency photovoltaics has been riddled with roadblocks such as toxicity and instability in widely used lead halide perovskites. Could we engineer a solar cell that delivers not just high performance, but also durability, stability and environmental safety?

That question led us to (Ca, Ba)ZrS3, a chalcogenide perovskite with immense promise. Unlike its lead-based counterparts, this material boasts strong thermal and chemical stability. More importantly, its bandgap can be finely tuned down to 1.26 eV with less than 2% calcium doping, placing it squarely within the Shockley-Queisser limit for optimal photovoltaic conversion.

For the first time, my research team at the Autonomous University of Querétaro explored an innovative idea of pairing (Ca, Ba)ZrS3 with next-generation inorganic spinel hole transport layers (HTLs). We integrated NiCo2O4, ZnCo2O4, CuCo2O4, and SrFe2O4 into solar cells and simulated their performance using SCAPS-1D.

Targeting malaria at the source: Drug-treated nets eliminate parasites in resistant mosquitoes

Researchers have identified a type of chemical compound that, when applied to insecticide-treated bed nets, appears to kill the malaria-causing parasite in mosquitoes.

Published in the journal Nature, the multi-site collaborative study represents a breakthrough for a disease that continues to claim more than half a million lives worldwide every year. A lab at Oregon Health & Science University played a key role, and the National Institute of Allergy and Infectious Diseases, of the National Institutes of Health, supported the research.

Michael Riscoe, Ph.D., professor of molecular microbiology and immunology in the OHSU School of Medicine, designed and synthesized the anti-malarial drugs, termed ELQs, that were then screened in the lab of Flaminia Catteruccia, Ph.D., the study’s senior author and Irene Heinz Given Professor of Immunology and Infectious Diseases at the Harvard T.H. Chan School of Public Health.

Scientists identify new 2D copper boride material with unique atomic structure

More than ten years ago, researchers at Rice University led by materials scientist Boris Yakobson predicted that boron atoms would cling too tightly to copper to form borophene, a flexible, metallic two-dimensional material with potential across electronics, energy and catalysis. Now, new research shows that prediction holds up, but not in the way anyone expected.

Unlike systems such as graphene on , where atoms may diffuse into the substrate without forming a distinct alloy, the in this case formed a defined 2D copper boride ⎯ a new compound with a distinct atomic structure. The finding, published in Science Advances by researchers from Rice and Northwestern University, sets the stage for further exploration of a relatively untapped class of 2D materials.

“Borophene is still a material at the brink of existence, and that makes any new fact about it important by pushing the envelope of our knowledge in materials, physics and electronics,” said Yakobson, Rice’s Karl F. Hasselmann Professor of Engineering and professor of materials science and nanoengineering and chemistry. “Our very first theoretical analysis warned that on copper, boron would bond too strongly. Now, more than a decade later, it turns out we were right ⎯ and the result is not , but something else entirely.”

Unique chemistry discovered in critical lithium deposits

Much of the world’s lithium occurs in salty waters with fundamentally different chemistry than other naturally saline waters like the ocean, according to a study published on May 23 in Science Advances. The finding has implications for lithium mining technologies and wastewater assessment and management.

Lithium is a critical mineral in the renewable energy sector. About 40% of global lithium production comes from large pans, called salars, in the central Andes Mountains in South America and the Tibetan Plateau in Asia. In these arid, high-altitude regions, lithium exists below surface salt deposits, dissolved in extremely saline water called .

“We discovered that the pH of brines in these regions is almost entirely driven by boron, unlike seawater and other common saline waters. This is a totally different geochemical landscape, like studying an extraterrestrial planet,” said Avner Vengosh, distinguished professor of environmental quality and Chair of the Division of Earth and Climate Sciences at Duke University’s Nicholas School of the Environment, who oversaw the research.

Moving pictures: Researchers use movies to diagnose EV battery failure

Charging electric-vehicle batteries in Ithaca’s frigid winter can be tough, and freezing temperatures also decrease the driving range. Hot weather can be just as challenging, leading to decomposition of battery materials and, possibly, catastrophic failure.

For (EVs) to be widely accepted, safe and fast-charging lithium-ion batteries need to be able to operate in extreme temperatures. But to achieve this, scientists need to understand how materials used in EVs change during temperature-related chemical reactions, a so-far elusive goal.

Now, Cornell chemists led by Yao Yang, Ph.D. ‘21, assistant professor of chemistry and chemical biology in the College of Arts and Sciences, have developed a way to diagnose the mechanisms behind battery failure in extreme climates using electron microscopy. Their first-of-its-kind operando (“operating”) electrochemical transmission electron microscopy (TEM) enables them to watch chemistry in action and collect real-time movies showing what happens to energy materials during temperature changes.