The chemical reaction 2KRb → K2 + Rb2 is studied under ultralow temperatures at the quantum state-to-state level, allowing unprecedented details of the reaction dynamics to be observed.
Category: chemistry – Page 321
Deconstruction of high-density polyethylene into liquid hydrocarbon fuels and lubricants
Plastic pollution has become one of the most pressing environmental issues now that the rapidly increased production of disposable plastic products is far beyond the world’s capacity for recycling and upcycling waste plastics. Although recent studies have provided a few catalytic strategies for producing value-added fuel and chemical products from polyethylene (PE) waste, the kinetic rates and/or selectivities are unsatisfactory, even with extended processing time (24 h) and high temperatures (280°C). This work reports a liquid-phase catalytic hydrogenolysis process that highly efficiently converts high-density PE to jet-fuel-and lubricant-range hydrocarbons under relatively mild conditions. The application of this efficient liquid-phase catalytic hydrogenolysis process could provide a promising approach for selectively producing high-value products, such as lubricants, from waste PE and other polyolefin polymers.
Study finds alarming levels of ‘forever chemicals’ in US mothers’ breast milk
They are linked to cancer, birth defects, liver disease, thyroid disease, plummeting sperm counts and a range of other serious health problems.
The peer-reviewed study, published on Thursday in the Environmental Science and Technology journal, found PFAS at levels in milk ranging from 50 parts per trillion (ppt) to more than 1850ppt.
Toxic chemicals known as PFAS found in all 50 samples tested at levels nearly 2000 times what is considered safe in drinking water.
Recycling gives new purpose to spent nuclear fuel
Imagine filling up your gas tank with 10 gallons of gas, driving just far enough to burn a half gallon and discarding the rest. Then, repeat. That is essentially the practice that the U.S. nuclear industry is following.
Spent nuclear fuel from power plants still has 95% of its potential to produce electricity. Current plans are to dispose of the spent nuclear fuel in a geologic repository. So, why is it not recycled? It turns out that separating usable versus unusable parts of spent nuclear fuel is complicated.
“Spent nuclear fuel contains roughly half of the periodic table. So, from a chemistry standpoint, there’s a lot going on,” said Gregg Lumetta, PNNL chemist and laboratory fellow. “And to reduce proliferation risk, it is best if pure plutonium is not produced at any point in the separation process.”
Clocking Electron Movements Inside an Atom – Shutter Speed of a Millionth of a Billionth of a Second
Scientists dramatically enhance the achievable resolution at free-electron lasers with a new technique.
Hard X-ray free-electron lasers (XFELs) have delivered intense, ultrashort X-ray pulses for over a decade. One of the most promising applications of XFELs is in biology, where researchers can capture images down to the atomic scale even before the radiation damage destroys the sample. In physics and chemistry, these X-rays can also shed light on the fastest processes occurring in nature with a shutter speed lasting only one femtosecond – equivalent to a millionth of a billionth of a second.
However, on these minuscule timescales, it is extremely difficult to synchronize the X-ray pulse that sparks a reaction in the sample on the one hand and the laser pulse which ‘observes’ it on the other. This problem is called timing jitter, and it is a major hurdle in ongoing efforts to perform time-resolved experiments at XFELs with ever-shorter resolution.
Genetically engineered grass cleanses soil of toxic pollutants left
Large swaths of U.S. military land are covered with munitions components, including the explosive chemical RDX. This molecule is toxic to people and can cause cancer. It also doesn’t naturally break down and can contaminate groundwater. Now researchers have genetically engineered a grass commonly used to fight soil erosion so that it can remove RDX from the soil, according to a new paper published May 3 in Nature Biotechnology.
A team, which includes researchers from the University of Washington, demonstrated that over the course of three years, a genetically engineered switchgrass could break down an explosive chemical in…
To make particles flow more efficiently, put an obstacle in their way
Scientists used to perform experiments by stirring biological and chemical agents into test tubes.
Nowadays, they automate research by using microfluidic chips the size of postage stamps. In these tiny devices, millions of microscopic particles are captured in droplets of water, each droplet serving as the “test tube” for a single experiment. The chip funnels these many droplets, one at a time, through a tiny channel where a laser probes each passing droplet to record thousands of experimental results each second.
These chips are used for such things as testing new antibiotics, screening drug compounds, sequencing the DNA and RNA of single cells, and otherwise speeding up the pace of scientific discovery.
Harvard researchers develop long-lasting solid-state battery
To combat this, Li and his team at Harvard have designed their solid-state battery with a multilayer approach that stacks its materials of varying stabilities between the anode and cathode. Much like a sandwich. This multi-material battery sandwich helps alleviate the penetration of lithium dendrites by controlling and containing them rather than preventing them altogether.
As you can see from the image above, the Harvard team has simplified its battery design to a form that’s more our speed. In this case, a BLT sandwich. The top slice of bread represents the lithium-metal anode, followed by lettuce appropriately representing a coating of graphite. The two layers of tomatoes represent the first electrolyte, protecting the delicious middle layer of bacon as the second electrolyte. Everything sits upon the bottom slice of bread, or the cathode. Is anyone else suddenly hungry for batteries?
In this design, dendrites are able to grow through the graphite (lettuce) and first electrolyte (tomato) but are halted when they reach the second electrolyte (bacon), thus preventing the dendrites from shorting the entire battery. This multilayer approach provokes chemistry that makes the second electrolyte too tight for the dendrites to penetrate. Furthermore, the Harvard researchers say this same chemistry can backfill the holes made by dendrites, essentially making the solid-state battery self-healing. Is there anything better than a sandwich that can regenerate itself? Honestly.
Dr. Natasha Bajema — Dir., Converging Risks Lab, Council on Strategic Risks — WMD Threat Reduction
Nuclear Nonproliferation, Cooperative Threat Reduction and WMD Terrorism — Dr. Natasha Bajema, Director, Converging Risks Lab, The Council on Strategic Risks.
Dr. Natasha Bajema, is a subject matter expert in nuclear nonproliferation, cooperative threat reduction and WMD terrorism, and currently serves as Director of the Converging Risks Lab, at The Council on Strategic Risks, a nonprofit, non-partisan security policy institute devoted to anticipating, analyzing and addressing core systemic risks to security in the 21st century, with special examination of the ways in which these risks intersect and exacerbate one another.
The Converging Risks Lab (CRL) is a research and policy development-oriented program designed to study converging, cross-sectoral risks in a rapidly-changing world, which brings together experts from multiple sectors of the security community, to ask forward-thinking questions about these converging risks, and to develop anticipatory solutions.
Dr. Bajema is also Founder and CEO of Nuclear Spin Cycle, a publishing and production company specializing in national security, entertainment, and publishing.
Prior to this, Dr. Bajema was at the Center for the Study of Weapons of Mass Destruction at the National Defense University, serving as Director of the Program for Emerging Leaders (PEL), as well as serving long-term detail assignments serving in various capacities in the Office of the Secretary of Defense, Acquisitions, Technology and Logistics, Nuclear, Chemical and Biological Defense Programs and in Defense Nuclear Nonproliferation at Department of Energy’s National Nuclear Security Administration.