tim knapen

An artist, a nerd and a designer walk into a bar.

[tim knapen @timknapen]

@DybusStephan These renders are getting good. phew!

[tim knapen @timknapen]

Love this type of deep scientific artistic analysis 😍

[thomas "noio" vandenberg @noio_games]

I thought this might be helpful to others trying to construct geometry for dynamic intersections.. It's not a full step-by-step but I added some of the essential points and lines that I hope will make it insightful

#gamedev #indiedev

[tim knapen @timknapen]

@lixielabs @tindie Why do you track Wayback Machine archives? What could that indicate?

[tim knapen @timknapen]

@zachlieberman Bookmarking this for later

[tim knapen @timknapen]

@paulg Pre singularity data pls

[tim knapen @timknapen]

@hturan Super fun! Where does the hand data come from?

[tim knapen @timknapen]

@Mr_Jangojim Perfect dimi!

[tim knapen @timknapen]

@UmerHAdil @ulkar_aghayeva Yes! This is the successful meme. "Publish and ask to be proven wrong?"

[Paul Stoffregen @PaulStoffregen]

If you ever made a project with Teensy 3.5 or 3.6 and need a replacement or spare, we're selling the very last of them today.

https://t.co/F2tFIClM6g

https://t.co/eZqowNg7Y2

Limit 2 per person. Limited quantity available. They will be discontinued when stock runs out.

[tim knapen @timknapen]

@PaulStoffregen End of an era! 😢

[tim knapen @timknapen]

@adafruit Doing the lord's work 💪🏻💪🏻

[tim knapen @timknapen]

@pikuma Very young grandma working with microcontrollers today.

[tim knapen @timknapen]

@mryalamanchi @snacpaccc @toybuilder Where do I subscribe?

[tim knapen @timknapen]

@DJSnM It's perfect if you want to encourage a cultural of untruths that are the most likely to propagate!

[tim knapen @timknapen]

@tomfleet @martinfasani @MaxClerkwell Wouldn't the font only be in the solder mask? So the shape of the letter wouldn't matter? Still a bad idea for usability I think.

[Alex Kaplan @alexkaplan0]

It's as close to official as we'll probably get: LK-99 is likely simply a ferromagnetic material, which explains its levitating properties, according to new research from Peking University.

The room temperature superconductivity revolution will have to wait another day.

[tim knapen @timknapen]

@lennyjpg Get the clicky and turny thing instead (OP-Z) !

[tim knapen @timknapen]

@lennyjpg Love a good debug view

[tim knapen @timknapen]

@fchollet Yep! Japan knows

[Andrew Côté @Andercot]

First video of LK-99 Full Levitation, aka flux-pinning

This video was just posted to the Chinese video-sharing site BiliBili and claims to be a highly pure synthesized sample of LK-99.

What is the physical phenomenon behind this and what does it mean?

Levitation of superconducting materials is a phenomenon unique to what is called Type-II superconductors, and is an effect whereby magnetic field lines becomes 'trapped' as it passes through the material, providing the force needed to levitate. These are the popular images and videos of cryogenically-cooled discs floating above a magnet frequently seen online and in the pinned post on my profile.

You can think of this like strands of hair being caught in gum - the gum is suspended in mid-air by adhering strongly to the hair as the hair passes through it. The hair in this case is magnetic field lines and the gum is the Type-II superconductor. Just like hair comes in individual strands, or in other words hair is 'quantized' or 'discrete', so is the flux trapped at the 'pinning centers' quantized in what are called 'magnetic vortices' - the quantization of pinned flux lines is a key property and distinguishing characteristic of Type-II superconductors (although technically can occur in Type-I superconductors if the material thickness is smaller than the London penetration depth, which is indeed very small - specifics for the physics nerds out there).

Flux-pinning is entirely unique to superconductors and is also wholly distinct from the Meissner effect. It is not a property of diamagnets or diamagnetism.

At @TRIUMFLab I contributed to flux-pinning studies in Niobium crystal superconducting radio-frequency cavities used for particle acceleration. In that application, trapped flux poses an issue by increasing the remnant surface resistivity of the cavity, which has the effect of decreasing its effective quality factor or Q-factor, which is a measurement of a resonators efficiency. SRF cavities typically have Q-factors of 10E10 and trapped flux at pinning centers reduces the maximum effective accelerating electric field used to drive charged particle bunches close to the speed of light.

Flux pinning is thought to arise in some Type-II superconductors by small imperfections in the crystal, also called volume defects, that enable flux to penetrate the material. In SRF cavities an issue that arises is any magnetic field that is passing through the material, e.g. by the Earth's background field, can become pinned or trapped inside the cavity as it transitions into a superconducting state. See some attached plots in the comments from a study showing how the surface resistivity of SRF cavities increases the more there is a background field as the cavity transitions into superconducting state.

This is the first video I am aware of that claims to show the flux-pinned levitation of a LK-99 sample. If this is in fact what is happening, then it is a very unique and promising finding of this new materials properties and potential for future study.

If this is real then it is truly ground-breaking