Set 2 by Ciro Santilli 35 Updated +Created
X-ray tube by Ciro Santilli 35 Updated +Created
Figure 1.
Toshiba D-088 dental X-ray tube
. Source.
Video 1. Source. Video sponsored by General Electric. A cool insight of this video is that a hot cathode is a more reliable electron source. Previous systems, and presumably including the discovery of X-rays, leftover gas in the tube was used. But this makes things more difficult to control, as we also want to remove as much gas as possible from the vacuum, otherwise electrons collide with the gas and lose energy before hitting the anode.
Video 2.
How Does X ray Tube Works by BiomedEngg
. Source. Describes in particular the rotating cathode method. Interesting observation that this is especially important since the cathode cannot cool quickly due to the vacuum.
PROMYS Europe 2024 problem set by Ciro Santilli 35 Updated +Created
PROMYS Europe application problem set by Ciro Santilli 35 Updated +Created
PROMYS Europe problem set answers by Ciro Santilli 35 Updated +Created
Oxford mathematics past exam paper by Ciro Santilli 35 Updated +Created
@cirosantilli/_file/gmp/gmp/hello.c by Ciro Santilli 35 Updated +Created
Erbium-doped fiber amplifier by Ciro Santilli 35 Updated +Created
This one was a huge advance it seems.
Video 1.
Erbium-doped fiber amplifier by Millennium Technology Prize
. Source.
X-ray source by Ciro Santilli 35 Updated +Created
PROMYS Europe 2024 by Ciro Santilli 35 Updated +Created
PROMYS Europe problem set by Ciro Santilli 35 Updated +Created
Fiber optical amplifier by Ciro Santilli 35 Updated +Created
These are pretty cool, they are basically a laser
GMP example by Ciro Santilli 35 Updated +Created
PROMYS Europe by Ciro Santilli 35 Updated +Created
European PROMYS offshoot hosted at the University of Oxford. Started in 2015.
The structure seems to be: come every day for 6 weeks, one problem sheet per day. Go.
Strongly against giving answer to problem sets... sad, as of 2024: promys-europe.org/students/faq (archive):
When do I get the solutions to the problems on the problem sets?
When you discover them for yourself: on your own or collaborating with other students. Returning students and counsellors and faculty will support and encourage you, but not by giving you the answers (hint: they don't even give hints). What PROMYS Europe does is offer you the tools and structure to enable you to be a creative mathematician.
and:
What rules are there at PROMYS Europe?
They're mostly the ones you'd expect: don't do anything dangerous or illegal, don't divide by zero, don't even try to skip Friday Fun, and don't give anyone solutions to the problem sets (though collaboration is definitely OK).
It does not seem to be the case for the American version however after a quick look: promys.org/programs/promys/for-students/faq/. Sad to see.
Also participants are strongly forbidden from sharing the problem sheets with anyone from outside the program. Ciro Santilli asked a participant face to face if he could take a look, but was told that they are not allowed to share it. So it is a very clear and strict order. Truly sad.
Fiber-optic communication by Ciro Santilli 35 Updated +Created
Optical amplifier by Ciro Santilli 35 Updated +Created
These are closely related to lasers, as they do a similar basic job: take a DC source as input and amplify light. Lasers just happen to use the input voltage to also generate the incoming light.
Pinned article: ourbigbook/introduction-to-the-ourbigbook-project
Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
Video 1.
Intro to OurBigBook
. Source.
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
    Video 2.
    OurBigBook Web topics demo
    . Source.
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    • to OurBigBook.com to get awesome multi-user features like topics and likes
    • as HTML files to a static website, which you can host yourself for free on many external providers like GitHub Pages, and remain in full control
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 5. . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
    Video 4.
    OurBigBook Visual Studio Code extension editing and navigation demo
    . Source.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact