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Archive for the ‘physics’ category: Page 211

Apr 30, 2020

A Second Look at the Second Gas Effect

Posted by in categories: information science, physics

The Newtonian laws of physics explain the behavior of objects in the everyday physical world, such as an apple falling from a tree. For hundreds of years Newton provided a complete answer until the work of Einstein introduced the concept of relativity. The discovery of relativity did not suddenly prove Newton wrong, relativistic corrections are only required at speeds above about 67 million mph. Instead, improving technology allowed both more detailed observations and techniques for analysis that then required explanation. While most of the consequences of a Newtonian model are intuitive, much of relativity is not and is only approachable though complex equations, modeling, and highly simplified examples.

In this issue, Korman et al.1 provide data from a model of the second gas effect on arterial partial pressures of volatile anesthetic agents. Most readers might wonder what this information adds, some will struggle to remember what the second gas effect is, and others will query the value of modeling rather than “real data.” This editorial attempts to address these questions.

The second gas effect2 is a consequence of the concentration effect3 where a “first gas” that is soluble in plasma, such as nitrous oxide, moves rapidly from the lungs to plasma. This increases the alveolar concentration and hence rate of uptake into plasma of the “second gas.” The second gas is typically a volatile anesthetic, but oxygen also behaves as a second gas.4 Although we frequently talk of inhalational kinetics as a single process, there are multiple steps between dialing up a concentration and the consequent change in effect. The key steps are transfer from the breathing circuit to alveolar gas, from the alveoli to plasma, and then from plasma to the “effect-site.” Separating the two steps between breathing circuit and plasma helps us understand both the second gas effect and the message underlying the paper by Korman et al.1

Apr 28, 2020

Scientists explore the power of radio waves to help control fusion reactions

Posted by in categories: nuclear energy, physics

A key challenge to capturing and controlling fusion energy on Earth is maintaining the stability of plasma—the electrically charged gas that fuels fusion reactions—and keeping it millions of degrees hot to launch and maintain fusion reactions. This challenge requires controlling magnetic islands, bubble-like structures that form in the plasma in doughnut-shaped tokamak fusion facilities. These islands can grow, cool the plasma and trigger disruptions—the sudden release of energy stored in the plasma—that can halt fusion reactions and seriously damage the fusion facilities that house them.

Improved island control

Research by scientists at Princeton University and at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) points toward improved control of the troublesome magnetic islands in ITER, the international tokamak under construction in France, and other future facilities that cannot allow large disruptions. “This research could open the door to improved control schemes previously deemed unobtainable,” said Eduardo Rodriguez, a graduate student in the Princeton Program in Plasma Physics and first author of a paper in Physics of Plasmas that reports the findings.

Apr 28, 2020

World’s first 3D simulations of superluminous supernovae

Posted by in categories: cosmology, physics, supercomputing

For most of the 20th century, astronomers have scoured the skies for supernovae—the explosive deaths of massive stars—and their remnants in search of clues about the progenitor, the mechanisms that caused it to explode, and the heavy elements created in the process. In fact, these events create most of the cosmic elements that go on to form new stars, galaxies, and life.

Because no one can actually see a supernova up close, researchers rely on to give them insights into the physics that ignites and drives the event. Now for the first time ever, an international team of astrophysicists simulated the three-dimensional (3D) physics of superluminous supernovae—which are about a hundred times more luminous than typical supernovae. They achieved this milestone using Lawrence Berkeley National Laboratory’s (Berkeley Lab’s) CASTRO code and supercomputers at the National Energy Research Scientific Computing Center (NERSC). A paper describing their work was published in Astrophysical Journal.

Astronomers have found that these superluminous events occur when a magnetar—the rapidly spinning corpse of a massive star whose magnetic field is trillions of times stronger than Earth’s—is in the center of a young supernova. Radiation released by the magnetar is what amplifies the supernova’s luminosity. But to understand how this happens, researchers need multidimensional simulations.

Apr 28, 2020

Scientists think we’ll finally solve nuclear fusion thanks to cutting-edge AI

Posted by in categories: nuclear energy, physics, robotics/AI

Scientists believe the world will see it’s first working thermonuclear fusion reactor by the year 2025. That’s a tall order in short form, especially when you consider that fusion has been “almost here” for nearly a century.

Fusion reactors – not to be confused with common fission reactors – are the holiest of Grails when it comes to physics achievements. According to most experts, a successful fusion reactor would function as a near-unlimited source of energy.

In other words, if there’s a working demonstration of an actual fusion reactor by 2025, we could see an end to the global energy crisis within a few decades.

Apr 27, 2020

New metasurface laser produces world’s first super-chiral light

Posted by in categories: energy, nanotechnology, physics

Researchers have demonstrated the world’s first metasurface laser that produces “super-chiral light”: light with ultra-high angular momentum. The light from this laser can be used as a type of “optical spanner” to or for encoding information in optical communications.

“Because can carry angular , it means that this can be transferred to matter. The more angular momentum light carries, the more it can transfer. So you can think of light as an ‘optical spanner’,” Professor Andrew Forbes from the School of Physics at the University of the Witwatersrand (Wits) in Johannesburg, South Africa, who led the research. “Instead of using a physical spanner to twist things (like screwing nuts), you can now shine light on the nut and it will tighten itself.”

The new produces a new high purity “twisted light” not observed from lasers before, including the highest angular momentum reported from a laser. Simultaneously the researchers developed a nano-structured that has the largest phase gradient ever produced and allows for high power operation in a compact design. The implication is a world-first laser for producing exotic states of twisted structured light, on demand.

Apr 26, 2020

A unique (so far) gravitational wave signal

Posted by in categories: cosmology, physics

Originally published by the Max Planck Institute for Gravitational Physics (Albert Einstein Institute, or AEI) in Hannover, Germany, on April 20, 2020.

The expectations of the gravitational-wave research community have been fulfilled: gravitational-wave discoveries are now part of their daily work as they have identified in the past observing run, O3, new gravitational-wave candidates about once a week. But now, the researchers have published a remarkable signal unlike any of those seen before: GW190412 is the first observation of a binary black hole merger where the two black holes have distinctly different masses of about 8 and 30 times that of our sun. This not only has allowed more precise measurements of the system’s astrophysical properties, but it has also enabled the LIGO and Virgo scientists to verify a yet-untested prediction of Einstein’s theory of general relativity.

Apr 24, 2020

Creator of Wolfram Alpha Has a Bold Plan to Find a New Fundamental Theory of Physics

Posted by in categories: computing, information science, neuroscience, physics

Stephen Wolfram is a cult figure in programming and mathematics. He is the brains behind Wolfram Alpha, a website that tries to answer questions by using algorithms to sift through a massive database of information. He is also responsible for Mathematica, a computer system used by scientists the world over.

Last week, Wolfram launched a new venture: the Wolfram Physics Project, an ambitious attempt to develop a new physics of our Universe.

The new physics, he declares, is computational. The guiding idea is that everything can be boiled down to the application of simple rules to fundamental building blocks.

Apr 24, 2020

How NASA is ‘pushing physics boundaries’ with ’faster than lightspeed‘ spacecraft design

Posted by in categories: physics, space travel

:oooo.


NASA is “pushing the boundaries of physics” by investing in a propulsion system that could allow a spacecraft to travel faster than the speed of light.

Apr 23, 2020

Cosmic beasts collision sings a loud gravitational wave hum

Posted by in categories: cosmology, physics

The collision of two black holes produced a gravitational wave signal unlike any other heard before.

Apr 19, 2020

Gravitational waves reveal unprecedented collision of heavy and light black holes

Posted by in categories: cosmology, physics

Researchers with the world’s gravitational wave detectors said today they had picked up vibrations from a cosmic collision that harmonized with the opening notes of an Elvis Presley hit. The source was the most exotic merger of two black holes detected yet—a pair in which one weighed more than three times as much as the other. Because of the stark mass imbalance, the collision generated gravitational waves at multiple frequencies, in a harmony Elvis fans would recognize. The chord also confirms a prediction of Einstein’s theory of gravity, or general relativity.

Such mismatched mass events could help theorists figure out how pairs of black holes form in the first place. “Anything that seems to be at the edge of our predictions is most interesting,” says Chris Belczynski, a gravitational theorist at the Polish Academy of Sciences in Warsaw, who was not involved in the observation. But the one event is “not quite in the regime where you can tell the different formation [routes] apart.”

Physicists first detected gravitational waves in 2015, when the Laser Interferometer Gravitational-Wave Observatory (LIGO), a pair of detectors in Washington and Louisiana, spotted two black holes spiraling into each other, generating infinitesimal ripples in spacetime. Two years later, the Virgo detector near Pisa, Italy, joined the hunt, and by August 2017, the detectors had bagged a total of 10 black hole mergers.