And the review determined that the two affected beams, both over 60 feet long, barely moved an inch due to the fractures. The redundancies in design guaranteed the beams’ stability. The overall safety of the building was never compromised. If those workers hadn’t discovered the cracks by chance, we still might not know about them.
Source: Salesforce Transit Center: San Francisco’s $2.2 Billion Cracks
Ever since the late 19th century, physicists have known about a counterintuitive property of some electric circuits called negative resistance. Typically, increasing the voltage in a circuit causes the electric current to increase as well. But under some conditions, increasing the voltage can cause the current to decrease instead. This basically means that pushing harder on the electric charges actually slows them down
Source: Counterintuitive physics property found to be widespread in living organisms
Their invention looks a lot like a solar panel. A flat metal panel is covered in a sheet of the material—a high-tech film—the trio invented. The material reflects the light and heat of the sun so effectively that the temperature beneath the film can drop 5 to 10-degrees Celsius (9 to 18-degrees Fahrenheit) lower than the air around it. A system of pipes behind the metal panel are exposed to that colder temperature, cooling the fluid inside before it’s sent out to current-day refrigeration systems.
Source: Scientists invented air conditioners for the climate change age — Quartz
Above a certain temperature, it becomes possible to replace the steam with supercritical carbon dioxide. This works more efficiently, potentially providing a boost of more than 20 percent, but it requires temperatures in excess of 1,000K. That makes things a bit more challenging, given that many metals will melt at such temperatures; others will react with carbon dioxide under these conditions. Finding a material that could work involves balancing a lot of factors, including heat and chemical resistance, ea
Source: New material could up efficiency of concentrated solar power | Ars Technica
The lens is quite unlike the curved disks of glass familiar from cameras and binoculars. Instead, it is made of a thin layer of transparent quartz coated in millions of tiny pillars, each just tens of nanometres across and hundreds high.
Singly, each pillar interacts strongly with light. Their combined effect is to slice up a light beam and remould it as the rays pass through the array
Source: Flat lens promises possible revolution in optics – BBC News
“The quality of our images is actually better than with a state-of-the-art objective lens. I think it is no exaggeration to say that this is potentially revolutionary.”
Diamond, being the world’s hardest substance, has a range of uses in creating cutting and polishing tools across industries from mining to medicine. The challenge is that diamond is expensive to mine and to manufacture, requiring high temperatures and high pressures. But by mixing up the substrates and controlling the rate of cooling, Narayan and his team have discovered they can create tiny diamonds within the Q-carbon.
Source: Q-carbon: A new phase of carbon so hard it forms diamonds when melted
For decades, metrologists have strived to retire ‘Le Grand K’ — the platinum and iridium cylinder that for 126 years has defined the kilogram from a high-security vault outside Paris. Now it looks as if they at last have the data needed to replace the cylinder with a definition based on mathematical constants.
Source: Kilogram conflict resolved at last : Nature News & Comment
If they are proved right, in 2018, Le Grand K will join the metre as a museum piece. “We’ll keep it,” says Davis, “but it won’t be defining anything anymore.”
Because these new magnets also have energy efficient characteristics, they can be used to create a new generation of sensors and actuators with vanishingly small heat signatures, said the researchers. These magnets could also find applications in efficient energy harvesting devices; compact micro-actuators for aerospace, automobile, biomedical, space and robotics applications; and ultra-low thermal signature actuators for sonars and defense applications.
Since these new magnets are composed of alloys that are free of rare-earth elements, they could replace existing rare-earth based magnetostriction alloys, which are expensive and feature inferior mechanical properties, said researchers.
Source: Expanding Magnets Have Potential to Energize the World | UMD Right Now :: University of Maryland
In very simple terms, when that happens, material properties such as resistance no longer depend on the length scales involved. So if electrons move without resistance on a tiny scale, they should also move without resistance on much larger scales too. Hence the phenomenon of superconductivity.
“We have described how it is possible for unparticles in strongly correlated matter to mediate superconductivity,” say LeBlanc and Grushin.
via ‘Unparticles’ May Hold The Key To Superconductivity, Say Physicists — The Physics arXiv Blog — Medium.