Decades-Long Quest Reveals Details of the Proton’s Inner Antimatter
Twenty years ago, physicists set out to investigate a mysterious asymmetry in the proton’s interior. Their results, published today, show how antimatter helps stabilize every atom’s core.
We learn in school that a proton is a bundle of three elementary particles called quarks — two “up” quarks and a “down” quark, whose electric charges (+2/3 and −1/3, respectively) combine to give the proton its charge of +1. But that simplistic picture glosses over a far stranger, as-yet-unresolved story.
In reality, the proton’s interior swirls with a fluctuating number of six kinds of quarks, their oppositely charged antimatter counterparts (antiquarks), and “gluon” particles that bind the others together, morph into them and readily multiply. Somehow, the roiling maelstrom winds up perfectly stable and superficially simple — mimicking, in certain respects, a trio of quarks.
The Design of the Roland Juno oscillators
This article is a comprehensive guide to the Roland Juno’s digitally-controlled analog oscillators (DCOs). I fell in love with the Juno early in my synthesizer journey and I’ve spent the last year or so doing research on its design so that I could create my own Juno-inspired DCO, Winterbloom’s Castor & Pollux.
Cameras and Lenses
Cameras and the lenses inside them may seem a little mystifying. In this blog post I’d like to explain not only how they work, but also how adjusting a few tunable parameters can produce fairly different results:
This is amazing work.
The US electrical system is not 120V
It’s more than 120V. It’s even more than the other 120V! It is the sum of the two (and sometimes a different two!) that makes us who we are. Learn about the US electrical system in this not-at-all snarky video!
Engineering and Technology History Wiki
The ETHW is not a “how-does-technology-work” site. The scope of the ETHW is historical; instead of focusing on the inner workings of technology, it aims to explain how the technology was developed, who were the major players involved, and what long term significance the technologies have. The ETHW is not only an encyclopedia of the history of technology, but it also contains a full range of materials that relate to the legacy of engineering, including personal accounts, documents, and multimedia objects. In that sense, it is a combination reference guide, blog, virtual archive, and on-line community.
In this blog post I’d like to look at these simple machines up close. I’ll explain how gears affect the properties of rotational motion and how the shape of their teeth is way more sophisticated than it may initially seem.
Movement is important in this article so most of the visualizations are animated – you can play and pause them by tapping on the button in their bottom left corner. By default the animations are enabled, but if you find them distracting, or you want to save power, you can globally pause all animations, just make sure to unpause them as needed.
This is very neat.
Project Silica proof of concept stores Warner Bros. ‘Superman’ movie on quartz glass
It was the first proof of concept test for Project Silica, a Microsoft Research project that uses recent discoveries in ultrafast laser optics and artificial intelligence to store data in quartz glass. A laser encodes data in glass by creating layers of three-dimensional nanoscale gratings and deformations at various depths and angles. Machine learning algorithms read the data back by decoding images and patterns that are created as polarized light shines through the glass.
How to wring power from the night air
Solar power is all very well, but it is available only during daylight hours. If something similarly environmentally friendly could be drawn on during the hours of darkness, that would be a great convenience. Colin Price, an atmospheric scientist at Tel Aviv University, in Israel, wonders if he might have stumbled across such a thing. As he told a meeting of the International Union of Geodesy and Geophysics, held in Montreal in July, it may be possible to extract electricity directly from damp air—specifically, from air of the sort of dampness (above 60% relative humidity) found after sundown, as the atmosphere cools and its ability to hold water vapour diminishes.
Survey of Alternative Displays
The purpose of this article is to collect and consolidate a list of these alternative methods of working with displays, light and optics. This will by no means be an exhaustive list of the possibilities available — depending on how you categorize, there could be dozens or hundreds of ways. There are historical mainstays, oddball one-offs, expensive failures and techniques that are only beginning to come into their own.
There’s more to life than the LCD.
Advanced Nuclear Power
The basic idea of a nuclear reactor is really simple. In fact, you could make a toy to explain it to kids.
Wireless nanowire lasers absorb infrared, emit blue light
So, where will these be used? I’ve no idea at this point, and I don’t really care—I just love the physics. More seriously, it takes a very bright light to turn a laser on like this (think ~1TW/cm2), so the applications will certainly be niche.
Nano Letters, 2019, DOI: 10.1021/acs.nanolett.9b00510
X-ray imaging reveals the secrets of termite mounds
Turner found that the assumptions of Pearce and others that the mounds’ complex tunnel systems serve to circulate air and remove heat to regulate interior temperatures isn’t accurate. The air mixing isn’t the result of the colony’s internal heat but air pressure from outside the mound. The termites build the mounds so tall to catch the wind, and their porous outer surface is what allows the air to move into and through the colony. Turner likens the effect to the alveoli in human lungs: the mound almost “breathes.”
Just going to link to the whole blog.
Mammalian Near-Infrared Image Vision through Injectable and Self-Powered Retinal Nanoantennae
Vision is an essential sensory modality for humans. Our visual system detects light between 400 and 700 nm (Dubois, 2009, Wyszecki and Stiles, 1982, Schnapf et al., 1988), so called visible light. In mammalian photoreceptor cells, light absorbing pigments, consisting of opsins and their covalently linked retinals, are known as intrinsic photon detectors. However, the detection of longer wavelength light, such as near-infrared (NIR) light, though a desirable ability, is a formidable challenge for mammals. This is because detecting longer wavelength light, with lower energy photons, requires opsins (e.g., human red cone opsins) to have much lower energy barriers. Consequently, this results in unendurable high thermal noise, thus making NIR visual pigments impractical (Ala-Laurila et al., 2003, Baylor et al., 1980, Luo et al., 2011, St George, 1952). This physical limitation means that no mammalian photoreceptor can effectively detect NIR light that exceeds 700 nm, and mammals are unable to see NIR light and to project a NIR image to the brain.
To this end, the successful integration of nanoparticles with biological systems has accelerated basic scientific discoveries and their translation into biomedical applications (Desai, 2012, Mitragotri et al., 2015). To develop abilities that do not exist naturally, miniature nanoscale devices and sensors designed to intimately interface with mammals including humans are of growing interest. Here, we report on an ocular injectable, self-powered, built-in NIR light nanoantenna that can extend the mammalian visual spectrum to the NIR range. These retinal photoreceptor-binding upconversion nanoparticles (pbUCNPs) act as miniature energy transducers that can transform mammalian invisible NIR light in vivo into short wavelength visible emissions (Liu et al., 2017, Wu et al., 2009). As sub-retinal injections are a commonly used ophthalmological practice in animals and humans (Hauswirth et al., 2008, Peng et al., 2017), our pbUCNPs were dissolved in PBS and then injected into the sub-retinal space in the eyes of mice. These nanoparticles were then anchored and bound to the photoreceptors in the mouse retina.
How an Explosion (Not Aliens) Turned New York’s Night Sky an Electric Blue
The bizarre illumination was sparked by an “electric arc flash” tied to faulty equipment at a Con Edison substation, a spokesman for the utility, Bob McGee, said early Friday. The equipment, located about 20 feet above the ground, contained cables that transmit 138,000 volts of electricity — a staggering amount compared with the 120 volts supplied to American households.
A better way to calculate pitch range
Today’s topic is a simple solution to a complicated problem. The complicated problem is how to estimate “pitch range” in recordings of human speakers. As for the simple solution — wait and see.
You might think that the many differences between the perceptual variable of pitch and the physical variable of fundamental frequency (“f0“) arise because perception is complicated and physics is simple. But if so, you’d be mostly wrong. The biggest problem is that physical f0 is a complex and often fundamentally incoherent concept. And even in the areas where f0 is well defined, f0 estimation (usually called “pitch tracking“) is prone to errors.
iPhones are Allergic to Helium
This piqued my interest, and I reached out to some friends that make ‘MEMS’ silicon. These microelectromechanical systems are some of the smallest mechanical apparatuses in the world. Every phone has gyroscopes and accelerometers with micrometer-thin elements. My initial theory, shared by some on Reddit, was that the helium molecules were small enough to get inside these chips and interfere with the mechanical workings.
Mystery of the cargo ships that sink when their cargo suddenly liquefies
When a solid bulk cargo liquefies, it can shift or slosh inside a ship’s hold, making the vessel less stable. A liquefied cargo can shift completely to one side of the hold. If it regains its strength and reverts to a solid state, the cargo will remain in the shifted position, causing the ship to permanently tilt or “list” in the water. The cargo can then liquefy again and shift further, increasing the angle of list.
FIU had grand plans for 'signature' bridge. But the design had a key mistake, experts say
The unconventional placement of diagonal supports in an uneven zig-zag pattern along the bridge produced a complex structural web with a glaring weakness at a key connection point, apparently overlooked by designers at FIGG Bridge Group, say three independent structural engineers who reviewed nearly 2,000 pages of calculations for the bridge at the Miami Herald’s request.
Follow up: https://www.nytimes.com/2019/10/22/us/bridge-collapse-florida-international-university-NTSB.html
A physical constant’s value shouldn’t depend on how you measure it
Measurements in physics are funny things. You’d hope that attempts to quantify some of the fundamental properties of the Universe would follow a simple pattern: they’d start with large error bars, but, over time, measuring technology improves and the error bars shrink. Ideally, the value would then remain nicely within the previous error.
It almost never really works like that.