Experiments disprove the general assumption that more than one wave mode is needed to produce a spectral pattern called a frequency comb.
Frequency Combs from Just One Mode
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Spectra from quasars suggest that intergalactic gas may have been heated by a form of dark matter called dark photons.
Dense gas clouds across the Universe absorb light from distant quasars, producing absorption lines in the quasar spectra. A new study shows that the larger-than-predicted widths of these lines from nearby gas clouds could result from a form of dark matter called dark photons [1]. These particles could heat the clouds, leading to a widening of the absorption lines. Other explanations of the broadening—based on more conventional heating sources—have been proposed, but if the dark-photon mechanism is at work, it might also cause heating in low-density clouds from earlier epochs of the Universe. Researchers are already planning to test this prediction.
When viewing the spectrum of a distant quasar, astronomers often observe absorption lines coming from the intervening clouds of gas. The most prominent absorption line is the Lyman-alpha line of hydrogen. Indeed, some quasar spectra have a “forest” of Lyman-alpha lines, with each coming from a cloud at a different distance from our Galaxy (or different epochs). By examining the widths, depths, and other details of the line shapes, researchers can extract information about the density, the temperature, and other features of the clouds. This information can be compared with the results of cosmological simulations that try to reproduce the clumping of matter into galaxies and other large-scale structures.
Patient-specific modeling could help clinicians determine whether an individual’s brain aneurysm is at risk of bursting.
Asphaltenes, a byproduct of crude oil production, are a waste material with potential. Rice University scientists are determined to find it by converting the carbon-rich resource into useful graphene.
Muhammad Rahman, an assistant research professor of materials science and nanoengineering, is employing Rice’s unique flash Joule heating process to convert asphaltenes instantly into turbostratic (loosely aligned) graphene and mix it into composites for thermal, anti-corrosion and 3D-printing applications.
The process makes good use of material otherwise burned for reuse as fuel or discarded into tailing ponds and landfills. Using at least some of the world’s reserve of more than 1 trillion barrels of asphaltene as a feedstock for graphene would be good for the environment as well.
Two-dimensional materials, which consist of just a single layer of atoms, can be packed together more densely than conventional materials, so they could be used to make transistors, solar cells, LEDs, and other devices that run faster and perform better.
One issue holding back these next-generation electronics is the heat they generate when in use. Conventional electronics typically reach about 80 degrees Celsius, but the materials in 2D devices are packed so densely in such a small area that the devices can become twice as hot. This temperature increase can damage the device.
This problem is compounded by the fact that scientists don’t have a good understanding of how 2D materials expand when temperatures rise. Because the materials are so thin and optically transparent, their thermal expansion coefficient (TEC)—the tendency for the material to expand when temperatures increase—is nearly impossible to measure using standard approaches.
Engineers at Caltech and the University of Southampton in England have collaboratively designed an electronics chip integrated with a photonics chip (which uses light to transfer data)—creating a cohesive final product capable of transmitting information at ultrahigh speed while generating minimal heat.
Though the two–chip sandwich is unlikely to find its way into your laptop, the new design could influence the future of data centers that manage very high volumes of data communication.
“Every time you are on a video call, stream a movie, or play an online video game, you’re routing data back and forth through a data center to be processed,” says Caltech graduate student Arian Hashemi Talkhooncheh, lead author of a paper describing the two-chip innovation that was published in the IEEE Journal of Solid-State Circuits on November 3.
O.o!!!
How to Spot a Neutrino
Neutrinos are very shy fundamental particles that don’t often interact with anything else. When they were first detected in the 1950s, physicists soon realized they would in some ways be ideal for astronomy.
The National Robotarium at Heriot-Watt University is focused on the development and testing of robotics and AI solutions By Hollie Tye Designing and manufacturing assisted living technologies, Pressalit were asked to contribute to the work being carried out by the Ambient Assisted Living Lab (AAL) at Heriot-Watt University Demonstrating how assisted living technologies can help transform lives, solutions […].
Solar panels often get a bad rap for spoiling the appearance of homes and businesses. Yet, this may be about to change.
Summary: A new study will investigate the genetic and biological mysteries of extreme longevity and healthy aging.
Source: american federation for aging research.
Decades of research will be aided by the results of a study launched today – the most ambitious ever conducted to uncover and understand the genetic and biological mysteries of exceptional longevity and healthy aging.