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Archive for the ‘chemistry’ category: Page 251

Apr 24, 2021

A strategy to rejuvenate dead lithium inside batteries

Posted by in categories: chemistry, computing, mobile phones

Li-ion batteries and other emerging lithium-based battery technologies are currently used to power a wide range of devices, including smartphones, laptops, tablets and cameras. Despite their advantages, batteries containing lithium do not always retain their performance over time.

One of the main reasons for the performance decay observed in some Li-based batteries is that the lithium contained within them sometimes becomes inactive or “dead.” This “dead lithium” can cause capacity decay and thermal runaway, which can ultimately reduce a battery’s lifespan and impair its performance.

Researchers at Zhejiang University of Technology in China and Argonne National Laboratory in the U.S. have recently devised a strategy to restore inactive lithium in Li anodes. This strategy, outlined in a paper published in Nature Energy, is based on a chemical reaction known as iodine redox.

Apr 23, 2021

Students make neutrons dance beneath Berkeley campus

Posted by in categories: biotech/medical, chemistry

Circa 2019


To create neutrons in the high flux neutron generator, UC Berkeley researchers heat up deuterium atoms in a vacuum chamber to 50000 degrees Celsius to obtain an ionized plasma (pink glow), then accelerate the ions until they collide and fuse with other deuterium atoms implanted in the titanium cathode, releasing neutrons in the process. The spiral coil is the water-cooled radio-frequency antenna that heats the plasma, viewed through a quartz window into the vacuum chamber. (UC Berkeley photo by Cory Waltz)

In an underground vault enclosed by six-foot concrete walls and accessed by a rolling, 25-ton concrete-and-steel door, University of California, Berkeley, students are making neutrons dance to a new tune: one better suited to producing isotopes required for geological dating, police forensics, hospital diagnosis and treatment.

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Apr 22, 2021

Levitation That’s No Trick: Scientists to Perform “Touchless” Chemical Reactions

Posted by in categories: chemistry, particle physics

Levitation has long been a staple of magic tricks and movies. But in the lab, it’s no trick. Scientists can levitate droplets of liquid, though mixing them and observing the reactions has been challenging. The pay-off, however, could be big as it would allow researchers to conduct contact-free experiments without containers or handling that might affect the outcome. Now, a team reporting in ACS’ Analytical Chemistry has developed a method to do just that.

Scientists have made devices to levitate small objects, but most methods require the object to have certain physical properties, such as electric charge or magnetism. In contrast, acoustic levitation, which uses sound waves to suspend an object in a gas, doesn’t rely on such properties. Yet existing devices for acoustic levitation and mixing of single particles or droplets are complex, and it is difficult to obtain measurements from them as a chemical reaction is happening. Stephen Brotton and Ralf Kaiser wanted to develop a versatile technique for the contactless control of two chemically distinct droplets, with a set of probes to follow the reaction as the droplets merge.

Apr 22, 2021

The Fuss Over Phosphorus

Posted by in categories: biological, chemistry, climatology, particle physics, space

Phosphorus, the element critical for life´s origin and life on Earth, may be even Venus.


Scientists studying the origin of life in the universe often focus on a few critical elements, particularly carbon, hydrogen, and oxygen. But two new papers highlight the importance of phosphorus for biology: an assessment of where things stand with a recent claim about possible life in the clouds of Venus, and a look at how reduced phosphorus compounds produced by lightning might have been critical for life early in our own planet’s history.

First a little biochemistry: Phosphine is a reduced phosphorus compound with one phosphorus atom and three hydrogen atoms. Phosphorus is also found in its reduced form in the phosphide mineral schreibersite, in which the phosphorus atom binds to three metal atoms (either iron or nickel). In its reduced form, phosphorus is much more reactive and useful for life than is phosphate, where the phosphorus atom binds to four oxygen atoms. Phosphorus is also the element that is most enriched in biological molecules as compared to non-biological molecules, so it’s not a bad place to start when you’re hunting for life.

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Apr 17, 2021

Possible life signs in the clouds of Venus

Posted by in categories: biological, chemistry, space

A new analysis of data from the 1978 Pioneer Venus mission, by researchers at Cal Poly Pomona, finds evidence not only for phosphine, but also possible chemical disequilibrium in Venus’ atmosphere, an additional possible sign of biological activity.

Apr 17, 2021

New Type of Battery Can Charge 10x Faster Than Lithium-Ion Models

Posted by in categories: chemistry, mobile phones

Rechargeable lithium-ion batteries are basically everywhere, powering everything from smartphones to notebooks, earbuds to gaming devices, and so much more.

But while the convenience of this ubiquitous (and Nobel Prize-winning) battery chemistry has radically changed the way we use and charge portable technology, lithium-ion is far from perfect.

The performance of lithium-ion batteries degrades over time, and sometimes flaws in the battery cells can lead to overheating and dangerous fire hazards – with companies sometimes having to issue urgent recalls for products that can explode without warning.

Apr 17, 2021

Dr. Patrick Bangert, Vice President of AI, Samsung SDS — Developing Next Gen AI To Serve Humanity

Posted by in categories: bitcoin, business, chemistry, information science, internet, robotics/AI

Developing Next Generation Artificial Intelligence To Serve Humanity — Dr. Patrick Bangert, Vice President of AI, Samsung SDS.


Dr. Patrick D. Bangert, is Vice President of AI, and heads the AI Engineering and AI Sciences teams, at Samsung SDS is a subsidiary of the Samsung Group, which provides information technology (IT) services, and are active in research and development of emerging IT technologies such as artificial intelligence (AI), blockchain, Internet of things (IoT) and Engineering Outsourcing.

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Apr 17, 2021

Toxic chemicals discovered in water systems across the US

Posted by in category: chemistry

Apr 16, 2021

Self-powered locomotion of a hydrogel water strider

Posted by in categories: chemistry, robotics/AI

Hydrogels are an exciting class of materials for new and emerging robotics. For example, actuators based on hydrogels have impressive deformability and responsiveness. Studies into hydrogels with autonomous locomotive abilities, however, are limited. Existing hydrogels achieve locomotion through the application of cyclical stimuli or chemical modifications. Here, we report the fabrication of active hydrogels with an intrinsic ability to move on the surface of water without operated stimuli for up to 3.5 hours. The active hydrogels were composed of hydrophobic and hydrophilic groups and underwent a dynamic wetting process to achieve spatial and temporal control of surface tension asymmetry. Using surface tension, the homogeneous active hydrogels propelled themselves and showed controlled locomotion on water, similar to common water striders.

Apr 13, 2021

Topological insulator metamaterial with giant circular photogalvanic effect

Posted by in categories: biological, chemistry, food, nanotechnology, physics, space

Topological insulators have notable manifestations of electronic properties. The helicity-dependent photocurrents in such devices are underpinned by spin momentum-locking of surface Dirac electrons that are weak and easily overshadowed by bulk contributions. In a new report now published on Science Advances, X. Sun and a research team in photonic technologies, physics and photonic metamaterials in Singapore and the U.K. showed how the chiral response of materials could be enhanced via nanostructuring. The tight confinement of electromagnetic fields in the resonant nanostructures enhanced the photoexcitation of spin-polarized surface states of a topological insulator to allow an 11-fold increase of the circular photogalvanic effect and a previously unobserved photocurrent dichroism at room temperature. Using this method, Sun et al. controlled the spin transport in topological materials via structural design, a hitherto unrecognized ability of metamaterials. The work bridges the gap between nanophotonics and spin electronics to provide opportunities to develop polarization-sensitive photodetectors.

Chirality

Chirality is a ubiquitous and fascinating natural phenomenon in nature, describing the difference of an object from its mirror image. The process manifests in a variety of scales and forms from galaxies to nanotubes and from organic molecules to inorganic compounds. Chirality can be detected at the atomic and molecular level in fundamental sciences, including chemistry, biology and crystallography, as well as in practice, such as in the food and pharmaceutical industry. To detect chirality, scientists can use interactions with electromagnetic fields, although the process can be hindered by a large mismatch between the wavelength of light and the size of most molecules at nanoscale dimensions. Designer metamaterials with structural features comparable to the wavelength of light can provide an independent approach to devise optical properties on demand to enhance the light-matter interaction to create and enhance the optical chirality of metamaterials. In this work, Sun et al.