Vinícius Vargas

[Vinícius Vargas @santunioni]

Hi @veritasium. Would you make a video about the World Cup ball? How did the Croatia’s draw goal got invalidated? We all saw this picture, but how do the peak compares to others?
- from a kick
- from a header
- from ground effect when ball travels just near
- from hitting a bird

[Vinícius Vargas @santunioni]

@dmwlff Except compiler output is deterministic for the input. For non determinism, who takes accountability on errors?

[benji @jaygi1011]

@MMAMircea Sean Strickland is literally Trevor Phillips from GTA V

[X @X]

power to the people

in 🇧🇷 & everywhere else

[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

[Mel Conway @conways_law]

Should we call flying an "inverse gravity manoeuver"?

[Vinícius Vargas @santunioni]

Assino embaixo e adiciono:

O approach microservice-first sempre falha. Como thumb-rule: comece simples, valide a funcionalidade com stakeholders, colha os diversos tipos de feedback, scale a arquitetura SE E SOMENTE SE seu #feedback disser que precisa. O…https://t.co/zxoY3fb1jT

[Vinícius Vargas @santunioni]

@jacob_moura eu acho que isso é mais efeito Brasil do que ser programador. O brasil é fábrica de ancaps

[Vinícius Vargas @santunioni]

@pagseguro
vocês não trabalham com RabbitMQ ou Kafka? foi um deploy errado que derrubou vocês? venceu o cartão da AWS?

[Vinícius Vargas @santunioni]

@fernandoulrich não consigo clicar em nenhum desses. Tem como deixar a vaga aberta?

[Vinícius Vargas @santunioni]

@igor_3k chama o peter karl marx libertário @ancapsu

[Vinícius Vargas @santunioni]

@rothbarbara_ Isso que vc descreveu acontece no mercado de artes há anos

[Vinícius Vargas @santunioni]

@ancapsu Olha a armadilha:
“15. O Lockdown não é possível pois o país não tem uma política de auxílio financeiro eficaz de apoio à população, ao comércio e à economia em geral”
Concordo totalmente que o lockdown não é possível mas discordo totalmente do motivo que apresentaram. Como vota?

[Vinícius Vargas @santunioni]

@DuckDuckGo could DuckDuckGo display an option which filter out in the search engine websites that ask cookies? If they start to lose accesses, they find another way to profit

[Vinícius Vargas @santunioni]

@_rschweitzer esse cara reincarnou Keynes 🥱

[Adriano Gianturco @AdrianoGianturc]

Há quem pensa que ditadura militar seja sinônimo de ordem, retidão, disciplina e moralidade.

Há quem pensa que comunismo e socialismo sejam sinônimo de justiça, igualdade, bem estar e progresso dos pobres.

E há quem pensa.

[Vinícius Vargas @santunioni]

@_rschweitzer Já respondo com essa: TEMER foi o melhor presidente da história desse país

[Vinícius Vargas @santunioni]

@RBReich Bottomless greed? don't you like cheap products? what happens when unions raise amazon costs so much that robots are cheaper workers? the human workers become unemployed. Will you force amazon to keep the workers even if it is unsuitable? What happens when the company bankrupts?

[Vinícius Vargas @santunioni]

@monark Esfera tem lado: O de dentro e o de fora