Tag: physics

Sushi physics

Master sushi chefs in Japan spend years honing their skills in making rice, selecting and slicing fish, and other techniques. Expert chefs even form the sushi pieces in a different way than a novice does, resulting in a cohesive bite that doesn’t feel all mushed together. In this short video clip from a longer Japanology episode on sushi, they put pieces of sushi prepared by a novice and a master through a series of tests — a wind tunnel, a pressure test, and an MRI scan — to see just how different their techniques are. It sounds ridiculous and goofy (and it is!) but the results are actually interesting.

1000x faster Metal Printing

The challenge with all these claims is that there’s no standard measure for printing speed, making these hard to compare. The best seems to be kg / h.

The SPEE3D printer has the potential to turn 3D metal printing, which currently is just making prototypes of parts, into a tool for manufacturing actual parts for use. It is up to 1000x quicker than conventional 3D metal printers.

Copper Rocket Nozzle
Print Time: 199 minutes
Weight: 17.9KG
Cost: $716
Speed: 5.4 kg / h

This 265mm x 300mm high, aerospace rocket nozzle liner was printed in pure copper on the WarpSPEE3D. Parts like these are typically machined out of solid wrought copper, a process that takes weeks and costs 10s of 1000s of $. The lead time for producing these parts is also typically around 6 months.

2022-03-20: Seurat uses a pixelization type approach to speed things up.

With the equivalent of 2.4m pixels projected in each square, the machine can print parts with layers just 25 microns thick at a rate of 3kg an hour. This is 10X faster than a typical L-BPF machine at such a fine resolution. Production versions of the Seurat Large-Area Pulsed Laser Powder Bed Fusion printer are now being built, and future generations of the machine should end up being 100x faster.

Area printing will be competitive with mass-production factory processes, such as machining, stamping and casting. By 2030 it will be possible to produce silverware for $25 a kilo. “That means we could actually print silverware cheaper than you could stamp them out”.

2023-05-13: Seurat lands a big customer

The part Seurat will produce for Siemens Energy is a turbine sealing segment made from a nickel-based alloy — it’s a component the company hadn’t previously considered as a candidate for 3D printing.

Over the 6-year length of the contract, Seurat will produce 59 tons of the sealing segments and related components. The big benefit is the potential cost savings, but the approach also reduces the emissions associated with producing the part, because Seurat’s technology is powered with solar and wind electricity that the company sources locally. The equation Seurat uses to talk about this is 1 metric ton of emissions reductions for every ton of components made. The approach also dramatically reduces the feedstock needed for production, which cuts down on scrap.

The shoelace mystery

The scientists expected that the knots would come undone slowly. But their slow-motion footage — focused on the shoelaces of a runner on a treadmill — showed that the knots rapidly failed within 1 or 2 strides. To figure out why, O’Reilly and his colleagues used an accelerometer on the tongue of a shoe to measure the forces acting on a knot. They found that when walking, the combined impact and acceleration on a shoelace totals a whopping 7G

State

In physics, math, and computer science, the state of a system is an encapsulation of all the information you’d ever need to predict what it will do, or at least its probabilities to do one thing versus another, in response to any possible prodding of it. In a sense, then, the state is a system’s “hidden reality,” which determines its behavior beneath surface appearances. But in another sense, there’s nothing hidden about a state—for any part of the state that never mattered for observations could be sliced off with Occam’s Razor, to yield a simpler and better description.

When put that way, the notion of “state” seems obvious. So then why did Einstein, Turing, and others struggle for years with the notion, along the way to some of humankind’s hardest-won intellectual triumphs?

Is Physical Law an Alien Intelligence?

Or to take this a step further, perhaps the behavior of normal cosmic matter that we attribute to dark matter is brought on by something else altogether: a living state that manipulates luminous matter for its own purposes. Consider that at present we have neither identified the dark-matter particles nor come up with a compelling alternative to our laws of physics that would account for the behavior of galaxies and clusters of galaxies. Would an explanation in terms of life be any less plausible than a failure of established laws?

Zeptosecond measurement

Physicists have measured photoionization, in which an electron exits a helium atom after excitation by light – for the first time with zeptosecond (10^-21 seconds) precision. This is the greatest accuracy of time determination of an event in the microcosm ever achieved, as well as the first absolute determination of the timescale of photoionization.

Metallic Hydrogen

Harvard researchers have studied and observed solid hydrogen under pressure at low temperatures. With increasing pressure we observe changes in the sample, going from transparent, to black, to a reflective metal, the latter studied at a pressure of 495 GPa. If it stays a metal at room temperature and after releasing pressure and was also a superconductor then it would be the holy grail of physics. Controlled nuclear fusion, production of metallic hydrogen, and high temperature superconductivity have been listed as the top 3 problems of physics. These problems all involve hydrogen and its isotopes.

Maxwell’s Demon

As far back as 1867, physicist James Clerk Maxwell described a hypothetical way to violate the Second Law: if a small theoretical being sat at the door between the hot and cold rooms and only let through particles traveling at a certain speed. This theoretical imp is called “Maxwell’s demon.”

“Although the violation is only on the local scale, the implications are far-reaching. This provides us a platform for the practical realization of a quantum Maxwell’s demon, which could make possible a local quantum perpetual motion machine.”