Tag Archives: speeds

Electrons in Graphene Accelerate to Supersonic Speeds

Posted on by
Reply
SEI 269385847

Hydraulic jumps occur when swift and slow streams of water intersect at a boundary.

Durk Gardenier / Alamy

Researchers have achieved an unprecedented feat: accelerating electrons to supersonic speeds, generating shock waves.

The flow of electricity through devices resembles the flow of a river, yet they differ greatly. Electrons collide with atoms as they traverse matter, while water droplets in a river frequently collide with one another. In 2016, scientists managed to make electrons flow like a viscous liquid in the ultrathin carbon material, graphene. Recently, Cory Dean and his team at Columbia University in New York have taken this further, introducing electrons into graphene, which resulted in a hydraulic jump due to the high speed of particle flow.

Picture a jump in water pressure while doing the dishes. When you turn on a faucet, you experience a similar phenomenon, with a chaotic ring-like border forming in the sink beneath, separating fast and slow flows. “In a way, it’s akin to a sonic boom happening in your kitchen sink,” remarks Doug Natelson from Rice University, who was not involved in the study.

Designing the electronic version was a complex task. The researchers crafted a microscopic nozzle using two layers of graphene, emulating the “de Laval nozzle,” a design from the 19th century often utilized in rocket engines. This nozzle is tapered in the center, allowing fluid to maintain acceleration and produce a shock wave upon exit if it reaches supersonic speeds within the constriction.

However, detecting the hydraulic jump posed a challenge, as it had never been observed with electrons before. Team member Abhay Pasupathy explains that instead of measuring electrons’ flow as usual, they utilized a specialized microscope to map the voltage at various points along the nozzle.

Natelson notes the intricate process of refining the graphene structure to ensure the electrons could “puff it in the cheek,” meaning they had to compress it sufficiently to enter this more dramatic phenomenon. The team’s achievement in resolving the hydraulic jump is technically remarkable, given the minuscule size of the graphene nozzle, according to Thomas Schmidt at the University of Luxembourg.

Now that they can accelerate electrons to such speeds, researchers aim to explore long-standing inquiries concerning charged shock waves. Dean mentions an ongoing debate about whether hydraulic jumps emit radiation that could potentially be harnessed for new infrared or radio generators. “Every experimenter we’re discussing with is figuring out how to detect this emission. Conversely, there’s a prevailing opinion among theorists that no emissions occur. There remains uncertainty about what is truly happening,” he concludes.

Topics:

  • Electricity/
  • Fluid Mechanics

Source: www.newscientist.com

NOAA Speeds Up Hiring for Forecast Positions Following National Weather Service Cuts

Posted on by
Reply

As some weather forecast offices discontinue overnight staffing, the National Weather Service is swiftly reassigning personnel internally, working to fill over 150 vacancies and address critical staffing gaps.

On Tuesday, the National Oceanic and Atmospheric Administration considered initiating a “reallocation period” to fill key positions that have remained unstaffed since the Trump administration’s decisions to dismiss probationary employees and incentivize veteran federal workers to retire early within the National Weather Service (NWS).

The agency is actively recruiting to fill five pivotal meteorologist roles overseeing field offices, including locations in Lake Charles, Louisiana; Houston, Texas; and Wilmington, Ohio.

Meanwhile, at least eight out of 122 weather forecasting offices nationwide—including those in Sacramento, California; Goodland, Kansas; and Jackson, Kentucky—have announced no plans to operate overnight or reduce overnight services in the coming six weeks, according to Tom Fahy, legislative director of the National Weather Service Employees Organization, which monitors staffing levels for the agency.

Critics of the recent cuts argue that the efforts to reassign meteorologists and other staff indicate severe reductions in services, negatively impacting vital public safety operations.

“This has never occurred before. We have always been an agency dedicated to providing 24/7 service to American citizens,” Fahy stated. “The potential risk is extremely high. If these cuts continue within the National Weather Service, lives could be lost.”

The National Weather Service acknowledged adjustments to its service levels and staffing but asserted that it continues to fulfill its mission and maintain the accuracy of forecasts.

“NOAA and NWS are dedicated to minimizing the impact of recent staffing changes to ensure that core mission functions persist,” the agency stated. “These efforts encompass temporary modifications to service levels and both temporary and permanent internal reallocations of meteorologists to offices with urgent needs.”

Fahy revealed that 52 of the nation’s 122 weather forecasting offices currently have staffing vacancy rates exceeding 20%.

The latest update on field office leadership, published on Wednesday, highlighted vacancy challenges, with 35 meteorologist positions at forecast offices remaining unfilled.

Since the new administration assumed power, the National Weather Service has reduced its workforce by more than 500 employees through voluntary early retirement packages for senior staff and the dismissal of probationary hires.

“Our greatest fear is that the weather offices will remain extremely understaffed, prompting unnecessary loss of life,” the director expressed earlier this month.

Recently retired NWS employees have voiced concerns that staffing levels have dropped below critical thresholds amid service freezes and the dismissal of many early-career professionals in probationary roles.

Alan Gerald, a former director at NOAA’s National Intensive Storm Institute who accepted early retirement in March, likened the NWS’s reassignment strategies to “deck chair relocation,” arguing that they fail to solve fundamental issues.

“They are merely shifting personnel from one office to another, which might address short-term crises, but that’s no sustainable solution,” Gerald remarked. “There’s no real influx of new staff.”

Brian Lamare, who recently retired from the Tampa Bay Area Weather Office in Florida, understands the desire to modernize and streamline services.

In fact, Lamare was involved in efforts to reorganize certain aspects of the service prior to the Trump administration.

The agency had plans to modernize its staffing structures by launching a “mutual assistance” system, allowing local forecast offices to request and offer aid during severe weather events or periods of understaffing.

“Many of these initiatives are now being expedited due to urgency,” Lamare commented. “When rearranging your living room furniture, you don’t set the house on fire—that’s the situation we are facing.”

Lamarre emphasized the necessity for the NWS to resume hiring as numerous forecasters in their 50s and 60s opted for voluntary retirement, leading to the loss of extensive experience. Concurrently, the agency has reduced its cohort of probationary employees, many of whom are just starting their careers.

“Eliminating probationary positions severely limits the agency’s future potential,” Lamare stated. “That’s where fresh, innovative talent is cultivated, making recruitment essential.”

Source: www.nbcnews.com

Chemistry expertise speeds up rocks’ ability to absorb CO2

Posted on by
Reply

Olivine rock naturally reacts with carbon dioxide, but it’s a slow business

Renhour48 via Wikimedia/CC0 1.0 Universal

The new process will allow crushed rocks to capture carbon dioxide more quickly from the air by turbocharged with already widely adopted carbon removal techniques.

Natural silicate minerals such as basalt react with water and CO2 to form solid carbonic acid materials, a process known as reinforced lock weathering (ERW). Research suggests Spreading crushed silicate rocks on farmland increases the amount of carbon the soil can absorb, while improving farmer crop yields.

but Matthew Canan Stanford University in California believes that the carbon advantage of ERW is exaggerated as natural silicates do not reach the climate quickly enough to extract large amounts of carbon from the atmosphere. “The data is very clear. They don’t weather at a useful speed,” he says.

Conversion of silicates into more reactive minerals increases weathering rates and makes ERW a viable climate solution, he says. Canaan and his colleagues Yuxuan Chen Stanford University also developed a method for producing magnesium oxide and calcium silicate using a process inspired by cement production.

“When you take calcium sources and magnesium silicate and heat it, you can make calcium silicate and magnesium oxide,” says Canaan. “The core reaction is what is called ion exchange, and it exchanges magnesium for calcium.”

“The reason it’s strong is because calcium silicate is reactive and so is magnesium oxide,” he says. “I put one reactive thing in and two come out.” The ingredients get the weather thousands of times faster than standard silicates, says Canaan.

The ki used in this process must be heated to 1400°C for the reaction, and energy may be provided by natural gas. This means that this method generates significant carbon emissions, but Canaan can capture these at sources or use several reactive minerals to capture the emissions at the site. It suggests that booking can offset it.

When the emissions associated with material production are taken into consideration, one ton of reactive material removes about one ton of carbon dioxide from the atmosphere. Researchers can now create 15 kilograms of reactive rocks per day, but they hope to turn the idea into a commercial venture by selling the materials to farmers for use on farmland.

Rachel James The University of Southampton, UK, challenges Canaan’s claim that traditional ERWs do not work, pointing to many documented examples of intensified weathering tests. However, she welcomes attempts to accelerate the weathering rate of silicate.

“The climate crisis now requires action, so what you can do to speed up weathering rates is extremely beneficial,” she says. “Weathering is essentially a slow process and frankly, we want to see meaningful carbon dioxide removal on a timescale of 10 years or more than 50 years.”

However, she warns that the team is likely to face problems with expanding production and deployment. She says that using minerals in agricultural systems does not guarantee that all captured carbon is permanently trapped.

Phil Renforth At Heriot Watt University in Edinburgh, UK, the proposal is said to be a smart idea, but it takes more research to understand how it should be unfolded. “They essentially produce cement minerals, which may not be an ideal candidate mineral in addition to agricultural soils,” he says.

topic:

Source: www.newscientist.com

Winds on the alien planet reach speeds of 33,000 kilometers per hour

Posted on by
Reply

Artist’s visualization of the gas giant WASP-127b

ESO/L.Calzada

The vast alien planet has fierce winds blowing around its equator at nearly 30 times the speed of sound on Earth.

Lisa Nortman He and his colleagues at the University of Göttingen in Germany used the European Southern Observatory’s Very Large Telescope in Chile to observe WASP-127b, a gas giant exoplanet more than 500 light-years from Earth. Although slightly larger than Jupiter, it is one of the least dense planets we know of.

The researchers expected the light signal from the planet’s atmosphere to have one distinct peak, but instead they found two distinct peaks.

“It was a little confusing,” Nortman says. “But when we analyzed the data a little more carefully, it became clear that there were two signals. I was very excited – my first thought was that it must be some kind of super-rotating wind. I thought that right away.”

The researchers concluded that the two mountains were caused by rapid winds from the jet stream near the equator, with half of the wind moving toward Earth and the other half moving away from it. The wind appears to be made up of water and carbon monoxide, and appears to be moving at 33,000 kilometers per hour, the fastest wind ever measured on Earth.

“We’re talking about nine kilometers per second. Even Jupiter’s wind speeds are on the order of a few hundred meters per second, so this is actually an order of magnitude bigger.” vivian parmentier at Oxford University.

He says that if you were in this wind, you wouldn’t be able to feel such extreme speeds because it would be moving around you at the same speed. But because the wind moves from the hot side of the Earth, which is always facing the star, to the cold side, which is always in darkness, you will experience a temperature difference of several hundred degrees in a few hours.

Researchers don’t know why WASP-127b has such extreme winds, but Nortman said the planet has certain peculiarities, including a low density and an unstable orbit around its star. It is said that there are certain characteristics that may play a role. “However, no clear connection has been established between those facts and particularly strong winds.”

topic:

Source: www.newscientist.com