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Archive for the ‘chemistry’ category: Page 279

Jul 13, 2020

Solar Flow Battery: Single Device Generates, Stores and Redelivers Renewable Electricity From the Sun

Posted by in categories: chemistry, solar power, sustainability

Chemists at the University of Wisconsin-Madison and their collaborators have created a highly efficient and long-lasting solar flow battery, a way to generate, store and redeliver renewable electricity from the sun in one device.

The new device is made of silicon solar cells combined with advanced solar materials integrated with optimally designed chemical components. The solar flow battery, made by the Song Jin lab in the UW-Madison chemistry department, achieved a new record efficiency of 20 percent. That bests most commercially available silicon solar cells used today and is 40 percent more efficient than the previous record holder for solar flow batteries, also developed by the Jin lab.

Jul 13, 2020

Spinning chemicals for faster reactions

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

Cardiff University scientists have devised a new way of making reactions up to 70 times faster by using state-of-the-art equipment to spin chemicals around.

They found that efficient mixing within a chemical reaction could be achieved by spinning chemicals and catalysts around in a small tube, causing the reactions to happen much quicker.

The new findings could have a profound influence on the way that chemicals are made in a wide variety of industries, from drug development to agriculture and fragrances.

Jul 13, 2020

Fires could be extinguished using beams of electricity

Posted by in categories: chemistry, particle physics

Circa 2011


It’s certainly an established fact that electricity can cause fires, but today a group of Harvard scientists presented their research on the use of electricity for fighting fires. In a presentation at the 241st National Meeting & Exposition of the American Chemical Society, Dr. Ludovico Cademartiri told of how they used a unique device to shoot beams of electricity at an open flame over one foot tall. Almost immediately, he said, the flame was extinguished. On a larger scale, such a system would minimize the amount of water that needed to be sprayed into burning buildings, both saving water and limiting water damage to those buildings.

Apparently, it has been known for over 200 years that electricity affects fire – it can cause flames to change in character, or even stop burning altogether. According to Cademartiri, a postdoctoral fellow in the group of Prof. George M. Whitesides at Harvard University, what hasn’t been looked into much is the science behind the relationship. It turns out that soot particles within flames can easily become charged, and therefore can cause flames to lose stability when the local electrical fields are altered.

Continue reading “Fires could be extinguished using beams of electricity” »

Jul 12, 2020

Rock ’n’ Control: Physicists Use Oscillations of Atoms to Control a Phase Transition

Posted by in categories: chemistry, particle physics

The goal of “Femtochemistry” is to film and control chemical reactions with short flashes of light. Using consecutive laser pulses, atomic bonds can be excited precisely and broken as desired. So far, this has been demonstrated for selected molecules. Researchers at the University of Göttingen and the Max Planck Institute for Biophysical Chemistry have now succeeded in transferring this principle to a solid, controlling its crystal structure on the surface. The results have been published in the journal Nature.

The team, led by Jan Gerrit Horstmann and Professor Claus Ropers, evaporated an extremely thin layer of indium onto a silicon crystal and then cooled the crystal down to −220 degrees Celsius. While the indium atoms form conductive metal chains on the surface at room temperature, they spontaneously rearrange themselves into electrically insulating hexagons at such low temperatures. This process is known as the transition between two phases – the metallic and the insulating – and can be switched by laser pulses. In their experiments, the researchers then illuminated the cold surface with two short laser pulses and immediately afterwards observed the arrangement of the indium atoms using an electron beam. They found that the rhythm of the laser pulses has a considerable influence on how efficiently the surface can be switched to the metallic state.

This effect can be explained by oscillations of the atoms on the surface, as first author Jan Gerrit Horstmann explains: “In order to get from one state to the other, the atoms have to move in different directions and in doing so overcome a sort of hill, similar to a roller coaster ride. A single laser pulse is not enough for this, however, and the atoms merely swing back and forth. But like a rocking motion, a second pulse at the right time can give just enough energy to the system to make the transition possible.” In their experiments, the physicists observed several oscillations of the atoms, which influence the conversion in very different ways.

Jul 12, 2020

Self Fuelled Transformable Liquid Metal Machine

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

Synthetic self-fuelled motors, which can spontaneously convert chemical energy into mechanical activity to induce autonomous locomotion, are excellent candidates for making self-powered machines, detectors/sensors, and novel robots. The present lab (Zhang et al. in Adv Mater 27:2648–2655, 2004 [1]). discovered an extraordinary self-propulsion mechanism of synthetic motors based on liquid metal objects. Such motors could swim in a circular Petri dish or different structured channels containing aqueous solution with a pretty high velocity on the order of centimeters per second, and surprisingly long lifetime lasting for more than one hour without any assistance of external energy. The soft material liquid metal enables the motors to self-deform, which makes them highly adaptable for accomplishing tough missions in special environment. Interestingly, the motors work just like biomimetic mollusk since they closely resemble the nature by “eating” aluminum as “food”, and can change shape by closely conforming to the geometrical space it voyages in. From practical aspect, one can thus develop a self-powered pump based on the actuation of the liquid metal enabled motor. Further, such pump can also be conceived to work as a cooler. Apart from different geometrical channels, several dominating factors, including the volume of the motor, the amount of aluminum, the property of the solution and the material of the substrate etc., have been disclosed to influence the performance of the autonomous locomotion evidently. This artificial mollusk system suggests an exciting platform for molding the liquid metal science to fundamentally advance the field of self-driven soft machine design, microfluidic systems, and eventually lead to the envisioned dynamically reconfigurable intelligent soft robots in the near future. In this chapter, the typical behaviors and fundamental phenomena of the self fuelled transformable liquid metal machines were illustrated.

Jul 10, 2020

Robot scientist discovers a new catalyst

Posted by in categories: biotech/medical, chemistry, robotics/AI

The robot seen here can work almost 24–7, carrying out experiments by itself. The automated scientist – the first of its kind – can make its own decisions about which chemistry experiments to perform next, and has already discovered a new catalyst.

With humanoid dimensions, and working in a standard laboratory, it uses instruments much like a human does. Unlike a real person, however, this 400 kg robot has infinite patience, and works for 21.5 hours each day, pausing only to recharge its battery.

This new technology – reported in the journal Nature and featured on the front cover – is designed to tackle problems of a scale and complexity that are currently beyond our grasp. New drug formulations could be autonomously discovered, for example, by searching vast and unexplored chemical spaces.

Jul 8, 2020

Physicists use oscillations of atoms to control a phase transition

Posted by in categories: chemistry, particle physics

The goal of ‘femtochemistry’ is to film and control chemical reactions with short flashes of light. Using consecutive laser pulses, atomic bonds can be excited precisely and broken as desired. So far, this has been demonstrated for selected molecules. Researchers at the University of Göttingen and the Max Planck Institute for Biophysical Chemistry have now succeeded in transferring this principle to a solid, controlling its crystal structure on the surface. The results have been published in the journal Nature.

The team, led by Jan Gerrit Horstmann and Professor Claus Ropers, evaporated an extremely thin layer of indium onto a silicon crystal and then cooled the crystal down to −220 degrees Celsius. While the indium form conductive metal chains on the at room temperature, they spontaneously rearrange themselves into electrically insulating hexagons at such low temperatures. This process is known as the transition between two phases—the metallic and the insulating—and can be switched by laser pulses. In their experiments, the researchers then illuminated the cold surface with two short laser pulses and immediately afterwards observed the arrangement of the indium atoms using an electron beam. They found that the rhythm of the has a considerable influence on how efficiently the surface can be switched to the metallic state.

This effect can be explained by oscillations of the atoms on the surface, as first author Jan Gerrit Horstmann explains: “In order to get from one state to the other, the atoms have to move in different directions and in doing so overcome a sort of hill, similar to a roller coaster ride. A single laser pulse is not enough for this, however, and the atoms merely swing back and forth. But like a rocking motion, a second pulse at the right time can give just enough energy to the system to make the transition possible.” In their experiments the physicists observed several oscillations of the atoms, which influence the conversion in very different ways.

Jul 7, 2020

Tiny Weed-Killing Robots Could Make Pesticides Obsolete

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

Clint Brauer’s farm outside of Cheney, Kansas, could be described as Old MacDonald’s Farm plus robots. Along with 5,500 square feet of vegetable-growing greenhouses, classes teaching local families to grow their food, a herd of 105 sheep, and Warren G—a banana-eating llama named after the rapper—is a fleet of ten, 140-pound, battery-operated robots.

Brauer, the co-founder of Greenfield Robotics, grew up a farm kid. He left for the big city tech and digital world, but eventually made his way back to the family farm. Now, it’s the R&D headquarters for the Greenfield Robotics team, plus a working farm.

When Brauer returned to his agricultural roots, he did so with a purpose: to prove that food could be grown without harmful chemicals and by embracing soil- and planet-friendly practices. He did just that, becoming one of the premier farmers growing vegetables in Kansas without pesticides, selling to local markets, grocery store chains, and chefs.

Jul 6, 2020

Compounds halt SARS-CoV-2 replication

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

As the death toll from the COVID-19 pandemic mounts, scientists worldwide continue their push to develop effective treatments and a vaccine for the highly contagious respiratory virus.

University of South Florida Health (USF Health) Morsani College of Medicine scientists recently worked with colleagues at the University of Arizona College of Pharmacy to identify several existing compounds that block replication of the COVID-19 virus (SARS-CoV-2) within grown in the laboratory. The inhibitors all demonstrated potent chemical and structural interactions with a critical to the virus’s ability to proliferate.

The research team’s discovery study appeared June 15 in Cell Research, a high-impact Nature journal.

Jul 6, 2020

Graphene barrier creates mosquito-proof fabric

Posted by in categories: biotech/medical, chemistry

(Credit: Getty Images)

According to the study in PNAS, the ultra-thin yet strong material acts as a barrier that mosquitoes can’t bite through. The graphene also blocks chemical signals mosquitoes use to sense that a blood meal is near, blunting their urge to bite in the first place.