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Posts tagged with "physics"

8bitfuture:

Worlds fastest camera shoots 4.4 trillion frames per second.
A Japanese team has created a recording device able to acquire 4.4 trillion images per second, at a 450 x 450 pixel resolution. The technique could be used to further research into heat conduction and chemical reactions, according to its creators.
If the resolution can be improved, it could also prove useful for manufacturing, where it could keep track of laser cuttings in real time.

The technique, known as a Sequentially Timed All-optical Mapping Photography, or STAMP for short, shuns the conventional methods employed by other superspeed cameras to achieve results up to 1,000 times faster than has been previously available. The current leading brand of high-speed real-time recording is a method unfortunately known as the pump-probe process, where light is “pumped” at the subject and then “probed” for absorption. STAMP differs from this by skipping the need to constantly probe, or measure, the scene to construct an image, instead it uses single-shot bursts to acquire images and maps the spatial profile of the subject to the temporal profile at a 450x450-pixel resolution.


Just to clarifying the below gif is imaging at 1 trillion frames per second. You can actually see light is slowed down enough to perceive it’s movement using one of these cameras.

8bitfuture:

Worlds fastest camera shoots 4.4 trillion frames per second.

A Japanese team has created a recording device able to acquire 4.4 trillion images per second, at a 450 x 450 pixel resolution. The technique could be used to further research into heat conduction and chemical reactions, according to its creators.

If the resolution can be improved, it could also prove useful for manufacturing, where it could keep track of laser cuttings in real time.

The technique, known as a Sequentially Timed All-optical Mapping Photography, or STAMP for short, shuns the conventional methods employed by other superspeed cameras to achieve results up to 1,000 times faster than has been previously available. The current leading brand of high-speed real-time recording is a method unfortunately known as the pump-probe process, where light is “pumped” at the subject and then “probed” for absorption. STAMP differs from this by skipping the need to constantly probe, or measure, the scene to construct an image, instead it uses single-shot bursts to acquire images and maps the spatial profile of the subject to the temporal profile at a 450x450-pixel resolution.

Just to clarifying the below gif is imaging at 1 trillion frames per second. You can actually see light is slowed down enough to perceive it’s movement using one of these cameras.

starstuffblog:

Researchers map quantum vortices inside superfluid helium nanodroplets
First ever snapshots of spinning nanodroplets reveal surprising features Scientists have, for the first time, characterized so-called quantum vortices that swirl within tiny droplets of liquid helium. The research, led by scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), the University of Southern California, and SLAC National Accelerator Laboratory, confirms that helium nanodroplets are in fact the smallest possible superfluidic objects and opens new avenues to study quantum rotation.
"The observation of quantum vortices is one of the most clear and unique demonstrations of the quantum properties of these microscopic objects," says Oliver Gessner, senior scientist in the Chemical Sciences Division at Berkeley Lab. Gessner and colleagues, Andrey Vilesov of the University of Southern California and Christoph Bostedt of SLAC National Accelerator Laboratory at Stanford, led the multi-facility and multi-university team that published the work this week in Science.
The finding could have implications for other liquid or gas systems that contain vortices, says USC’s Vilesov. “The quest for quantum vortices in superfluid droplets has stretched for decades,” he says. “But this is the first time they have been seen in superfluid droplets.” Superfluid helium has long captured scientist’s imagination since its discovery in the 1930s. Unlike normal fluids, superfluids have no viscosity, a feature that leads to strange and sometimes unexpected properties such as crawling up the walls of containers or dripping through barriers that contained the liquid before it transitioned to a superfluid.
Helium superfluidity can be achieved when helium is cooled to near absolute zero (zero kelvin or about -460 degrees F). At this temperature, the atoms within the liquid no longer vibrate with heat energy and instead settle into a calm state in which all atoms act together in unison, as if they were a single particle.
For decades, researchers have known that when superfluid helium is rotated—in a little spinning bucket, say—the rotation produces quantum vortices, swirls that are regularly spaced throughout the liquid. But the question remained whether anyone could see this behavior in an isolated, nanoscale droplet. If the swirls were there, it would confirm that helium nanodroplets, which can range in size from tens of nanometers to microns, are indeed superfluid throughout and that the motion of the entire liquid drop is that of a single quantum object rather than a mixture of independent particles.
But measuring liquid flow in helium nanodroplets has proven to be a serious challenge. “The way these droplets are made is by passing helium through a tiny nozzle that is cryogenically cooled down to below 10 Kelvin,” says Gessner. “Then, the nanoscale droplets shoot through a vacuum chamber at almost 200 meters-per-second. They live once for a few milliseconds while traversing the experimental chamber and then they’re gone. How do you show that these objects, which are all different from one another, have quantum vortices inside?”
The researchers turned to a facility at SLAC called the Linac Coherent Light Source (LCLS), a DOE Office of Science user facility that is the world’s first x-ray free-electron laser. This laser produces very short light pulses, lasting just a ten-trillionth of a second, which contain a huge number of high-energy photons. These intense x-ray pulses can effectively take snapshots of single, ultra-fast, ultra-small objects and phenomena.
"With the new x-ray free electron laser, we can now image phenomenon and look at processes far beyond what we could imagine just a decade ago," says Bostedt of SLAC. "Looking at the droplets gave us a beautiful glimpse into the quantum world. It really opens the door to fascinating sciences."
In the experiment, the researchers blasted a stream of helium nanodroplets across the x-ray laser beam inside a vacuum chamber; a detector caught the pattern that formed when the x-ray light diffracted off the drops.
The diffraction patterns immediately revealed that the shape of many droplets were not spheres, as was previously assumed. Instead, they were oblate. Just as the Earth’s rotation causes it to bulge at the equator, so too do rotating nanodroplets expand around the middle and flatten at the top and bottom.
But the vortices themselves are invisible to x-ray diffraction, so the researchers used a trick of adding xenon atoms to the droplets. The xenon atoms get pulled into the vortices and cluster together.
"It’s similar to pulling the plug in a bathtub and watching the kids’ toys gather in the vortex," says Gessner. The xenon atoms diffract x-ray light much stronger than the surrounding helium, making the regular arrays of vortices inside the droplet visible. In this way, the researchers confirmed that vortices in nanodroplets behave as those found in larger amounts of rotating superfluid helium.
Armed with this new information, the researchers were able to determine the rotational speed of the nanodroplets. They were surprised to find that the nanodroplets spin up to 100,000 times faster than any other superfluid helium sample ever studied in a laboratory.
Moreover, while normal liquid drops will change shape as they spin faster and faster—to resemble a peanut or multi-lobed globule, for instance—the researchers saw no evidence of such shapeshifting in the helium nanodroplets. “Essentially, we’re exploring a new regime of quantum rotation with this matter,” Gessner says.
"It’s a new kind of matter in a sense because it is a self-contained isolated superfluid," he adds. "It’s just all by itself, held together by its own surface tension. It’s pretty perfect to study these system
 IMAGE…This is an illustration of analysis of superfluid helium nanodroplets. Droplets are emitted via a cooled nozzle (upper right) and probed with x-ray from the free-electron laser. The multicolored pattern (upper left) represents a diffraction pattern that reveals the shape of a droplet and the presence of quantum vortices such as those represented in the turquoise circle with swirls (bottom center).
Credit: Felix P. Sturm and Daniel S. Slaughter, Berkeley Lab.

starstuffblog:

Researchers map quantum vortices inside superfluid helium nanodroplets

First ever snapshots of spinning nanodroplets reveal surprising features

Scientists have, for the first time, characterized so-called quantum vortices that swirl within tiny droplets of liquid helium. The research, led by scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), the University of Southern California, and SLAC National Accelerator Laboratory, confirms that helium nanodroplets are in fact the smallest possible superfluidic objects and opens new avenues to study quantum rotation.

"The observation of quantum vortices is one of the most clear and unique demonstrations of the quantum properties of these microscopic objects," says Oliver Gessner, senior scientist in the Chemical Sciences Division at Berkeley Lab. Gessner and colleagues, Andrey Vilesov of the University of Southern California and Christoph Bostedt of SLAC National Accelerator Laboratory at Stanford, led the multi-facility and multi-university team that published the work this week in Science.

The finding could have implications for other liquid or gas systems that contain vortices, says USC’s Vilesov. “The quest for quantum vortices in superfluid droplets has stretched for decades,” he says. “But this is the first time they have been seen in superfluid droplets.”

Superfluid helium has long captured scientist’s imagination since its discovery in the 1930s. Unlike normal fluids, superfluids have no viscosity, a feature that leads to strange and sometimes unexpected properties such as crawling up the walls of containers or dripping through barriers that contained the liquid before it transitioned to a superfluid.

Helium superfluidity can be achieved when helium is cooled to near absolute zero (zero kelvin or about -460 degrees F). At this temperature, the atoms within the liquid no longer vibrate with heat energy and instead settle into a calm state in which all atoms act together in unison, as if they were a single particle.

For decades, researchers have known that when superfluid helium is rotated—in a little spinning bucket, say—the rotation produces quantum vortices, swirls that are regularly spaced throughout the liquid. But the question remained whether anyone could see this behavior in an isolated, nanoscale droplet. If the swirls were there, it would confirm that helium nanodroplets, which can range in size from tens of nanometers to microns, are indeed superfluid throughout and that the motion of the entire liquid drop is that of a single quantum object rather than a mixture of independent particles.

But measuring liquid flow in helium nanodroplets has proven to be a serious challenge. “The way these droplets are made is by passing helium through a tiny nozzle that is cryogenically cooled down to below 10 Kelvin,” says Gessner. “Then, the nanoscale droplets shoot through a vacuum chamber at almost 200 meters-per-second. They live once for a few milliseconds while traversing the experimental chamber and then they’re gone. How do you show that these objects, which are all different from one another, have quantum vortices inside?”

The researchers turned to a facility at SLAC called the Linac Coherent Light Source (LCLS), a DOE Office of Science user facility that is the world’s first x-ray free-electron laser. This laser produces very short light pulses, lasting just a ten-trillionth of a second, which contain a huge number of high-energy photons. These intense x-ray pulses can effectively take snapshots of single, ultra-fast, ultra-small objects and phenomena.

"With the new x-ray free electron laser, we can now image phenomenon and look at processes far beyond what we could imagine just a decade ago," says Bostedt of SLAC. "Looking at the droplets gave us a beautiful glimpse into the quantum world. It really opens the door to fascinating sciences."

In the experiment, the researchers blasted a stream of helium nanodroplets across the x-ray laser beam inside a vacuum chamber; a detector caught the pattern that formed when the x-ray light diffracted off the drops.

The diffraction patterns immediately revealed that the shape of many droplets were not spheres, as was previously assumed. Instead, they were oblate. Just as the Earth’s rotation causes it to bulge at the equator, so too do rotating nanodroplets expand around the middle and flatten at the top and bottom.

But the vortices themselves are invisible to x-ray diffraction, so the researchers used a trick of adding xenon atoms to the droplets. The xenon atoms get pulled into the vortices and cluster together.

"It’s similar to pulling the plug in a bathtub and watching the kids’ toys gather in the vortex," says Gessner. The xenon atoms diffract x-ray light much stronger than the surrounding helium, making the regular arrays of vortices inside the droplet visible. In this way, the researchers confirmed that vortices in nanodroplets behave as those found in larger amounts of rotating superfluid helium.

Armed with this new information, the researchers were able to determine the rotational speed of the nanodroplets. They were surprised to find that the nanodroplets spin up to 100,000 times faster than any other superfluid helium sample ever studied in a laboratory.

Moreover, while normal liquid drops will change shape as they spin faster and faster—to resemble a peanut or multi-lobed globule, for instance—the researchers saw no evidence of such shapeshifting in the helium nanodroplets. “Essentially, we’re exploring a new regime of quantum rotation with this matter,” Gessner says.

"It’s a new kind of matter in a sense because it is a self-contained isolated superfluid," he adds. "It’s just all by itself, held together by its own surface tension. It’s pretty perfect to study these system


IMAGE…This is an illustration of analysis of superfluid helium nanodroplets. Droplets are emitted via a cooled nozzle (upper right) and probed with x-ray from the free-electron laser. The multicolored pattern (upper left) represents a diffraction pattern that reveals the shape of a droplet and the presence of quantum vortices such as those represented in the turquoise circle with swirls (bottom center).

Credit: Felix P. Sturm and Daniel S. Slaughter, Berkeley Lab.

astrodidact:

http://pda.sciencealert.com.au/news/20141305-25508.html

hmmm…

Researchers have proved that the amount of heat graphene conducts changes depending on the length of the sample.
This contradicts Fourier’s law, which states thermal conductivity is an intrinsic material property that’s independent of size or shape.

astrodidact:

http://pda.sciencealert.com.au/news/20141305-25508.html

hmmm…

Researchers have proved that the amount of heat graphene conducts changes depending on the length of the sample.

This contradicts Fourier’s law, which states thermal conductivity is an intrinsic material property that’s independent of size or shape.

Hello! :) I was wondering why the electromagnetic spectrum stops at gamma rays. Why is there no kind of radiation with even more energy? Does it have to do with a "limit" on such small wavelengths (meaning, it's not possible to have a smaller wavelength)? Or is it because there is nothing in the universe capable of actually producing radiation with a higher energy than gamma rays? I was reading about GRB's and began wondering. :) Thanks a lot!

nanodash:

nanodash:

Hello!

Right…time to go research. NASA is probably a good place to start, hang on…

Well that didn’t help. Anyways.

The definition of gamma rays is a quare little duck. These days it’s that (with the exception of astronomical sources, which are crazy energetic anyway) X-Rays come from electrons and gamma rays come from nuclei (Like in radioactive decay). But this isn’t a strict definition, people mix them all the time. And yeah, the reason there’s nothing above them for now is the most energetic sources in the galaxy still just make gamma rays. The properties of the photon would have to change to call it something else. But…and here’s where it gets (more) interesting.

How big could a photon’s energy be? Well…The bigger the energy, the smaller the wavelength. The smallest length possible is theorised to be the Planck length. The Planck length is the smallest theoretical length that could ever be measured. Beyond that notions of space kind of break down. A photon that had a wavelength equal to the Planck length would have about 10 billion joules (10 Gigajoules) of energy). That’s about the same as 25 lightning bolts. In a single photon.

If you made a 5mW laser (a laser pointer) using these photons, to keep up that power it would need to release a single photon every 76000 years.

Which is awesome.

In case you missed it

mindblowingscience:

Getting a charge out of water droplets

Last year, MIT researchers discovered that when water droplets spontaneously jump away from superhydrophobic surfaces during condensation, they can gain electric charge in the process. Now, the same team has demonstrated that this process can generate small amounts of electricity that might be used to power electronic devices.
The new findings, by postdoc Nenad Miljkovic, associate professor of mechanical engineering Evelyn Wang, and two others, are published in the journalApplied Physics Letters.
This approach could lead to devices to charge cellphones or other electronics using just the humidity in the air. As a side benefit, the system could also produce clean water.
The device itself could be simple, Miljkovic says, consisting of a series of interleaved flat metal plates. Although his initial tests involved copper plates, he says any conductive metal would do, including cheaper aluminum.

Continue Reading.

mindblowingscience:

Getting a charge out of water droplets

Last year, MIT researchers discovered that when water droplets spontaneously jump away from superhydrophobic surfaces during condensation, they can gain electric charge in the process. Now, the same team has demonstrated that this process can generate small amounts of electricity that might be used to power electronic devices.

The new findings, by postdoc Nenad Miljkovic, associate professor of mechanical engineering Evelyn Wang, and two others, are published in the journalApplied Physics Letters.

This approach could lead to devices to charge cellphones or other electronics using just the humidity in the air. As a side benefit, the system could also produce clean water.

The device itself could be simple, Miljkovic says, consisting of a series of interleaved flat metal plates. Although his initial tests involved copper plates, he says any conductive metal would do, including cheaper aluminum.

Continue Reading.

txchnologist:

Electric Fields Made Visible

Physics educator James Lincoln helps people understand the natural world. The gifs above are from a Youtube video he made on how to “see” an electric field, the region around a charged object where electric force is experienced. When the object is positively charged, electric field lines extend radially outward from the object. When the object is negatively charged, the lines extend radially inward.  

Click the gifs for more info or see the full video below.

Read More

mindblowingscience:

Tiny Twisters Whirl Around Inside Drops of Helium

Inside a single wheel-shaped droplet of liquid helium rotating 2 million times per second, scientists have spotted a storm of dozens of tiny tornadoes whirling around.
The droplets of liquid helium spun 100,000 times faster than in any previous experiments. The grid of quantum tornadoes inside the droplets could reveal interesting information on the bizarre nature of “superfluid” liquid helium and the nature of quantum rotation, say the international team of scientists involved in the study.
"The quest for quantum vortices in superfluid droplets has stretched for decades," Andrey Vilesov, a professor of chemistry at the University of Southern California, said in a statement. “But this is the first time they have been seen in superfluid droplets.”

Continue Reading.

mindblowingscience:

Tiny Twisters Whirl Around Inside Drops of Helium

Inside a single wheel-shaped droplet of liquid helium rotating 2 million times per second, scientists have spotted a storm of dozens of tiny tornadoes whirling around.

The droplets of liquid helium spun 100,000 times faster than in any previous experiments. The grid of quantum tornadoes inside the droplets could reveal interesting information on the bizarre nature of “superfluid” liquid helium and the nature of quantum rotation, say the international team of scientists involved in the study.

"The quest for quantum vortices in superfluid droplets has stretched for decades," Andrey Vilesov, a professor of chemistry at the University of Southern California, said in a statement. “But this is the first time they have been seen in superfluid droplets.”

Continue Reading.

laboratoryequipment:

'Lightning Rods' Channel Electricity Through AirBy zapping the air with a pair of powerful laser bursts, researchers at the Univ. of Arizona have created highly focused pathways that can channel electricity through the atmosphere.The technique can potentially direct an electrical discharge up to 33 feet away or more, shattering previous distance records for transmitting electricity through air. It also raises the intriguing possibility of one day channeling lightning with laser power.Read more: http://www.laboratoryequipment.com/news/2014/08/lightning-rods-channel-electricity-through-air

laboratoryequipment:

'Lightning Rods' Channel Electricity Through Air

By zapping the air with a pair of powerful laser bursts, researchers at the Univ. of Arizona have created highly focused pathways that can channel electricity through the atmosphere.

The technique can potentially direct an electrical discharge up to 33 feet away or more, shattering previous distance records for transmitting electricity through air. It also raises the intriguing possibility of one day channeling lightning with laser power.

Read more: http://www.laboratoryequipment.com/news/2014/08/lightning-rods-channel-electricity-through-air

ucresearch:

How to float a ping pong ball in mid-air

Dianna “Physics Girl” Cowern, physicist at UC San Diego’s Center for Astrophysics and Space Sciences, explains in this video how The Coandă Effect can make a ping pong ball float in mid-air.

Read more about Diana Cowern and her quest to encourage girls to pursue science.

Aug 7
nanodash:

I love Quantum Physics. It’s so utterly mad and counter-intuitive that we’ve had to start naming ideas after Alice in Wonderland characters.
You know how in Alice in Wonderland the Cheshire Cat disappeared and left its grin behind? Well in the 90’s a professor in Tel Aviv theorised that you could do the same with particles, separate them from their properties. A Quantum Cheshire Cat. And last week it was proven true.
It would like taking the green out of grass. You’d still have the grass, but you’d also have a region of green somewhere else.
Or if you could take the taste out of a chocolate bar, and have the bar in one hand, and an area of taste in the other.
Well a group in Vienna have done it, they passed a beam of neutrons through a silicon crystal and split the electrons from their magnetic moment (How susceptible something is to a magnetic field) So they had a beam of neutrons, and a beam of magnetic moment.
If Quantum Physics doesn’t melt your brain, you haven’t understood it.

nanodash:

I love Quantum Physics. It’s so utterly mad and counter-intuitive that we’ve had to start naming ideas after Alice in Wonderland characters.

You know how in Alice in Wonderland the Cheshire Cat disappeared and left its grin behind? Well in the 90’s a professor in Tel Aviv theorised that you could do the same with particles, separate them from their properties. A Quantum Cheshire Cat. And last week it was proven true.

It would like taking the green out of grass. You’d still have the grass, but you’d also have a region of green somewhere else.

Or if you could take the taste out of a chocolate bar, and have the bar in one hand, and an area of taste in the other.

Well a group in Vienna have done it, they passed a beam of neutrons through a silicon crystal and split the electrons from their magnetic moment (How susceptible something is to a magnetic field) So they had a beam of neutrons, and a beam of magnetic moment.

If Quantum Physics doesn’t melt your brain, you haven’t understood it.