Non-Coalescence of Fluid Jets and Drops
Why in the world won’t these streams of liquid mix even though they are colliding? They are the same fluid of silicone oil, yet they just bounce off of each other.
This is because there is a thin film of air surrounding the jets of liquid, and the motion of the jets maintains the air-film barrier indefinitely.
A little bit like the way antibubbles work…
(via physicsshiny)
A materials scientist has created the world’s toughest fiber using a mechanism based on a slip knot.The paper itself is found here.
Google and NASA Launch Quantum Computing AI Lab
Quantum computing took a giant leap forward on the world stage today as NASA and Google, in partnership with a consortium of universities, launched an initiative to investigate how the technology might lead to breakthroughs in artificial intelligence.
The new Quantum Artificial Intelligence Lab will employ what may be the most advanced commercially available quantum computer, the D-Wave Two, which a recent study confirmed was much faster than conventional machines at defeating specific problems. The machine will be installed at the NASA Advanced Supercomputing Facility at the Ames Research Center in Silicon Valley and is expected to be available for government, industrial, and university research later this year.
Google believes quantum computing might help it improve its web search and speech recognition technology. University researchers might use it to devise better models of disease and climate, among many other possibilities. As for NASA, “computers play a much bigger role within NASA missions than most people realize,” says quantum computing expert Colin Williams, director of business development and strategic partnerships at D-Wave.
(via turing-machine)
A gentle lead-in to the subject, Feynman starts by discussing photons and their properties.
Feynman’s lectures were originally given as the Sir Douglas Robb lectures at the University of Auckland, New Zealand in 1979. Videotapes of these lectures were made publicly available on a not-for-profit basis in 1996.Learn more about QED here (Courtesy of Indiana University).
X-ray vision tracks lightning bursts
Blink and you’ve missed it. Researchers in the US have captured the world’s first X-ray images of lightning, by creating a special camera that can capture radiation at 10 million frames per second. They presented their new findings at the American Geophysical Union (AGU) Fall Meeting in San Francisco and they say that this new view of lightning could help to solve some of the mysteries of this spectacular natural phenomenon.
The research was carried out at the International Center for Lightning Research and Testing, located in Florida. It is one of the few sites in world where lightning is initiated and studied under controlled conditions. By firing rockets with trailing wires into thunder clouds, scientists are able to generate electric fields that are large enough to trigger bolts of lightning, which then propagate back down towards the rocket launch tower.
Joseph Dwyer and colleagues at the Florida Institute of Technology became interested in the fact that lightning emits X-rays as it propagates through the air, a phenomenon that was only noted in the past decade. But given that X-ray sources in lightning travel through the Earth’s atmosphere at velocities approaching the speed of light, it is difficult to catch them on camera before they disappear. In addition, they cannot be imaged with standard mirrors and lenses because huge amounts of material are required to prevent X-rays and gamma rays from entering through the sides of a camera.
Dwyer’s team has created a customized camera that has 30 detectors made from a combination of sodium iodide and photomultiplier tubes, each measuring 3 × 3 inch. The device, which is approximately the size of a standard refrigerator, is also equipped with a 3 inch pinhole aperture, and can record X-rays at 10 million frames per second. “This is actually a very old technique for making images, like that seen in a camera obscura,” Dwyer says.
During July and August this year, Dwyer’s team studied four rocket-triggered lightning flashes at the Florida test site. Each flash lasted for approximately two seconds and the resulting sequences of images revealed that X-rays emerged primarily from the vicinity of the lightning tip as it propagated towards the Earth. As the lightning crashed into the control tower it also triggered large bursts of gamma radiation, which were also captured by the camera.
“For the first time we’re catching a glimpse of lightning in the X-ray emission,” says Dwyer. “We’re seeing lightning as Superman would see it with his X-ray vision”.
Credit: James Dacey/physicsworld.com
(via thecraftychemist)
A longstanding joke holds that practical fusion power is about 20 years away and always will be. One simple phenomenon explains why practical, self-sustaining fusion reactions have proved difficult to achieve: Turbulence in the superhot, electrically charged gas, called plasma, that circulates inside …
I noticed that the “plasma physics” tag is very empty yesterday, which I found very surprising. I decided to take it upon myself to read more about plasmas and post the papers and articles I read in order to provide more resources for those interested in the subject.
Dye laser
A dye laser is a laser which uses an organic dye as the lasing medium, usually as a liquid solution. Compared to gases and most solid state lasing media, a dye can usually be used for a much wider range of wavelengths. The wide bandwidth makes them particularly suitable for tunable lasers and pulsed lasers. Moreover, the dye can be replaced by another type in order to generate different wavelengths with the same laser, although this usually requires replacing other optical components in the laser as well.
Dye lasers were independently discovered by P. P. Sorokin and F. P. Schäfer (and colleagues) in 1966.
The dyes used in these lasers contain rather large organic molecules which fluoresce. The incoming light excites the dye molecules into the state of being ready to emit stimulated radiation, the singlet state. In this state, the molecules emit light via fluorescence, and the dye is transparent to the lasing wavelength. Within a microsecond, or less, the molecules will change to their triplet state. In the triplet state, light is emitted via phosphorescence, and the molecules absorb the lasing wavelength, making the dye opaque. Liquid dyes also have an extremely high lasing threshold. Flashlamp pumped lasers need a flash with an extremely short duration, to deliver the large amounts of energy necessary to bring the dye past threshold before triplet absorption overcomes singlet emission. Dye lasers with an external pump laser can direct enough energy of the proper wavelength into the dye with a relatively small amount of input energy, but the dye must be circulated at high speeds to keep the triplet molecules out of the beam path.
In laser medicine these lasers are applied in several areas, including dermatology where they are used to make skin tone more even. The wide range of wavelengths possible allows very close matching to the absorption lines of certain tissues, such as melanin or hemoglobin, while the narrow bandwidth obtainable helps reduce the possibility of damage to the surrounding tissue. They are used to treat port-wine stains and other blood vessel disorders, scars and kidney stones. They can be matched to a variety of inks for tattoo removal, as well as a number of other applications.
In spectroscopy, dye lasers can be used to study the absorption and emission spectra of various materials. Their tunability, (from the near-infrared to the near-ultraviolet), narrow bandwidth, and high intensity allows a much greater diversity than other light sources. The variety of pulse widths, from ultra-short, femto-second pulses to continuous-wave operation, makes them suitable for a wide range of applications, from the study of fluorescent lifetimes and semiconductor properties to lunar laser ranging experiments.
Image Credit: Warsash Scientific
(Phys.org) Two French researchers, Guilhem Larrieu and Xiang-Lei Han, may have succeeded in possibly setting back the date to which Moore’s Law would no longer apply by creating a new kind of nanowire Field-Effect Transistor (FET). In their paper published in the journal Nanoscale, the two describe …
A quick video demonstrating superfluidity, a state of matter where the substance (here, Helium-4) has no viscosity.
(Source: kill3rtcell)
(Phys.org) Superconductors can radically change energy management as we know it, but most are commercially unusable because they only work close to absolute zero. A research group at EPFL has now published an innovative approach that may help us understand and use superconductivity at more realistic …
“Graham Farmelo on Paul Dirac and Mathematical Beauty”
A friend of mine once sent me this video expecting me to only watch the first ten minutes. I was hooked immediately and watched the whole hour without ever once looking away from the screen.
I know I say this on a regular basis, but can I just be Dirac?
Leonard Susskind: My Friend Richard Feynman
Onstage at TEDxCaltech, physicist Leonard Susskind spins a few stories about his friendship with the legendary Richard Feynman, discussing his unconventional approach to problems both serious and … less so.
♪ I gotta have my orange juice
Just a little bit of orange juice ♪
- Richard Feynman [x]
_________
Feynman was insane! Hahaha.
(via neuronsandneutrons)
I was trying to figure out why I keep getting my directions backwards for these magnetic fields, and I just realized that I kept trying to do the “right hand rule” with my left hand so I would not have to put down my pencil.
*facepalm*
