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Archive for the ‘chemistry’ category: Page 174

Aug 3, 2022

Red mud is piling up. Can scientists figure out what to do with it?

Posted by in categories: chemistry, economics, food, sustainability

Practical and glamorous, aluminium is prized for making products from kitchen foil and beverage cans to Tesla Roadsters and aircraft. But the silvery metal—abundant, cheap, lightweight, and corrosion resistant—has a dark side: red mud. This brownish red slurry, a caustic mishmash of metal-and silicon-rich oxides, often with a dash of radioactive and rare earth elements, is what’s left after aluminum is extracted from ore. And it is piling up. Globally, some 3 billion tons of red mud are now stored in massive waste ponds or dried mounds, making it one of the most abundant industrial wastes on the planet. Aluminum plants generate an additional 150 million tons each year.

Red mud has become trouble looking for a place to happen. In 2010, an earthen dam at one waste pond in Hungary gave way, unleashing a 2-meter-high wall of red mud that buried the town of Ajka, killing 10 people and giving 150 severe chemical burns. (See more on the dangers posed by waste dams.) Even when red mud remains contained, its extreme alkalinity can leach out, poison groundwater, and contaminate nearby rivers and ecosystems. Such liabilities, as well as growing regulatory pressure on industry to develop sustainable practices, have catalyzed global efforts to find ways to recycle and reuse red mud. Some researchers are developing ways to extract the valuable rare earth metals, whereas others turn the mud into cement or bricks.

“There is hope here,” says Yiannis Pontikes, a mechanical engineer at KU Leuven. But economic and marketing hurdles remain, and “the clock is ticking” as regulators consider new controls, says Efthymios Balomenos, a metallurgical engineer at the National Technical University of Athens. “At some point we will not be able to produce waste. So, there is an urgent need to make changes.”

Aug 3, 2022

Visualising sigma orbitals opens path to new understanding of surface chemistry

Posted by in categories: chemistry, mapping

Photoemisssion orbital tomography extended beyond pi orbitals.


Figure

Experimentally-generated map of copper surface using photoemission orbital tomography (top left) and the projected densities of states of σ and π orbitals (top right). The bianthracene investigated in the study (bottom left) and maps of its σ orbitals (bottom middle, right)

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Aug 3, 2022

Cosmic Buckyballs Could Be The Source of Mysterious Infrared Light

Posted by in categories: chemistry, quantum physics

Scientists may have just tracked down the source of some mysterious infrared glows detected emanating from stars and clouds of interstellar dust and gas.

These Unidentified Infrared Emission (UIE) bands have baffled scientists for decades; according to a theoretical new work, at least some of these bands can be produced by highly ionized buckminsterfullerene, more commonly known as buckyballs.

“I am extremely honored to have played a part in the astonishingly complex quantum chemistry investigations undertaken by Dr Sadjadi that have led to these very exciting results,” said astrophysicist Quentin Parker of Hong Kong University’s Laboratory for Space Research.

Aug 2, 2022

Newly-discovered chemical reactions could explain how life began on Earth

Posted by in category: chemistry

Read more about Newly-discovered chemical reactions could explain how life began on Earth on Devdiscourse.

Aug 1, 2022

Research finds mechanically driven chemistry accelerates reactions in explosives

Posted by in categories: chemistry, engineering, physics, supercomputing

Scientists at the Lawrence Livermore National Laboratory (LLNL) Energetic Materials Center and Purdue University Materials Engineering Department have used simulations performed on the LLNL supercomputer Quartz to uncover a general mechanism that accelerates chemistry in detonating explosives critical to managing the nation’s nuclear stockpile. Their research is featured in the July 15 issue of the Journal of Physical Chemistry Letters.

Insensitive high explosives based on TATB (1,3,5-triamino-2,4,6-trinitrobenzene) offer enhanced safety properties over more conventional explosives, but physical explanations for these safety characteristics are not clear. Explosive initiation is understood to arise from hotspots that are formed when a shockwave interacts with microstructural defects such as pores. Ultrafast compression of pores leads to an intense localized spike in temperature, which accelerates chemical reactions needed to initiate burning and ultimately . Engineering models for insensitive high explosives—used to assess safety and performance—are based on the hotspot concept but have difficulty in describing a wide range of conditions, indicating missing physics in those models.

Using large-scale atomically resolved reactive molecular dynamics supercomputer simulations, the team aimed to directly compute how hotspots form and grow to better understand what causes them to react.

Jul 31, 2022

A new robotic submersible could unlock the mysteries of Greenland’s underwater glaciers

Posted by in categories: chemistry, climatology, robotics/AI, sustainability

You’re in for a surprise.

Picture the ocean, impacted by climate change.

Rising sea levels, ocean acidification, melting of ice sheets, flooded coastlines, and shrinking fish stocks — the image is largely negative. For the longest time, the ocean has been portrayed as a victim of climate change, and rightly so. Ulf Riebesell, Professor of Biological Oceanography at the Geomar Helmholtz Centre for Ocean Research Kiel, has studied the effects of global warming on the ocean for nearly 15 years, warning the scientific community about the impacts of climate change on ocean life and biochemical cycles. countries aiming to achieve a climate-neutral world by mid-century, experts have decided to include the ocean to tackle climate change.

Jul 31, 2022

Researchers turn discarded CDs into flexible and stretchable biosensors

Posted by in categories: chemistry, materials

The CD was initially soaked in 40 mL of acetone for 1.5 minutes, releasing the metal layer by breaking down the polycarbonate substrate. The metal from the CD was easily harvested with polyimide tape, which also serves as the substrate layer in the new device integration to improve the mechanical durability and robustness of the thin metal film.

“When you pick up your hair on your clothes with sticky tape, that is essentially the same mechanism,” said Assistant Professor Ahyeon Koh, who led the research. “We loosen the layer of metals from the CD and then pick up that metal layer with tape, so we just peel it off. That thin layer is then processed and flex ible.”

Researchers created the sensors utilizing a commercially available Cricut cutter, an off-the-shelf machine for crafters that generally cut designs from materials like paper, vinyl, card stock, and iron-on transfers. The flexible circuits then would be removed and stuck onto a person. The whole fabrication process was completed in 20–30 minutes, without releasing toxic chemicals or needing expensive equipment, and it costs about $1.50 per device.

Jul 31, 2022

Development of solid-state electrolytes for sodium-ion battery–A short review

Posted by in categories: chemistry, nuclear energy, particle physics, space, sustainability

Nowadays, the development of renewable energy sources, such as wind, solar, and nuclear energy sources, has become imperative, due to the limited resource constraints of the traditional fossil fuels [1 ]. However, these renewable sources could not deliver a regular power supply as the sources are variable in time and diffuse in space. Thus, the focus has been shifted to the electrical energy storage to smooth the intermittency of the energy sources. Rechargeable battery has the ability to store chemical energy and convert it into electrical energy with high efficiency [ 2]. Lithium-ion battery (LIB), as one typical rechargeable electrochemical battery, has dominated the markets of portable electronic devices, electric vehicles, and hybrid electric vehicles in the past decades, due to its high output voltages, high energy densities, and long cycle life; even though the high cost and the shortage of lithium resources are inhibiting the application of LIB in large-scale energy storage [[3], [4], [5], [6], [7], [8], [9]].

Sodium-ion battery (SIB) is one promising alternative to LIB, with comparable performance to that of LIB, abundant sodium resources and low price of starting materials [[10], [11], [12], [13]]. As Na atom is heavier and larger than those of Li atom, the gravimetric and volumetric energy density of Na-ion battery are expected to not exceed those of the Li analogues [14]. However, energy density would not be considered as the critical issue in the field of large-scale grid support, for which the operating cost and the battery durability are the most important aspects [15,16].

Jul 30, 2022

New bioremediation material can clean ‘forever chemicals’

Posted by in categories: biotech/medical, chemistry, engineering, food, health

A novel bioremediation technology for cleaning up per-and polyfluoroalkyl substances, or PFAS, chemical pollutants that threaten human health and ecosystem sustainability, has been developed by Texas A&M AgriLife researchers. The material has potential for commercial application for disposing of PFAS, also known as “forever chemicals.”

Published July 28 in Nature Communications, the was a collaboration of Susie Dai, Ph.D., associate professor in the Texas A&M Department of Plant Pathology and Microbiology, and Joshua Yuan, Ph.D., chair and professor in Washington University in St. Louis Department of Energy, Environmental and Chemical Engineering, formerly with the Texas A&M Department of Plant Pathology and Microbiology.

Removing PFAS contamination is a challenge

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Jul 29, 2022

Scientists discover new ‘origins of life’ chemical reactions

Posted by in categories: biotech/medical, chemistry

Four billion years ago, the Earth looked very different than it does today, devoid of life and covered by a vast ocean. Over the course of millions of years, in that primordial soup, life emerged. Researchers have long theorized how molecules came together to spark this transition. Now, scientists at Scripps Research have discovered a new set of chemical reactions that use cyanide, ammonia and carbon dioxide—all thought to be common on the early earth—to generate amino acids and nucleic acids, the building blocks of proteins and DNA.

“We’ve come up with a new paradigm to explain this shift from prebiotic to biotic chemistry,” says Ramanarayanan Krishnamurthy, Ph.D., an associate professor of chemistry at Scripps Research, and lead author of the new paper, published July 28, 2022 in the journal Nature Chemistry. “We think the kind of reactions we’ve described are probably what could have happened on .”

In addition to giving researchers insight into the chemistry of the early earth, the newly discovered chemical reactions are also useful in certain , such as the generation of custom labeled biomolecules from inexpensive starting materials.