Cavity magnetron Updated +Created
Apparently, DC current comes in, and microwaves come out.
TODO: sample power efficiently of this conversion and output spectrum of this conversion on some cheap device we can buy today.
Video 1.
Magnetron, How does it work? by Lesics (2020)
Source.
Video 2.
Device that Won WW2 by Curious Droid
. Source.
Cayley graph Updated +Created
You select a generating set of a group, and then you name every node with them, and you specify:
  • each node by a product of generators
  • each edge by what happens when you apply a generator to each element
Not unique: different generating sets lead to different graphs, see e.g. two possible en.wikipedia.org/w/index.php?title=Cayley_graph&oldid=1028775401#Examples for the
CC BY-NC-SA Updated +Created
Too restrictive. People should be able to make money from stuff.
The definition of "commercial" could also be taken in extremely broad senses, making serious reuse risky in many applications.
Notably, many university courses use it, notably MIT OpenCourseWare. Ciro wonders if it is because academics are wary of industry, or if they want to make money from it themselves. This reminds Ciro of a documentary he watched about the origins of one an early web browsers in some American university. And then that university wanted to retain copyright to make money from it. But the PhDs made a separate company nonetheless. And someone from the company rightly said something along the lines of:
The goal of universities is to help create companies and to give back to society like that. Not to try and make money from inventions.
TODO source.
The GNU project does not like it either www.gnu.org/licenses/license-list.en.html#CC-BY-NC:
This license does not qualify as free, because there are restrictions on charging money for copies. Thus, we recommend you do not use this license for documentation.
In addition, it has a drawback for any sort of work: when a modified version has many authors, in practice getting permission for commercial use from all of them would become infeasible.
en.wikipedia.org/wiki/Creative_Commons_NonCommercial_license#Defining_%22Noncommercial%22 also talks about the obvious confusion this generates: nobody can agree what counts as commercial or not!
In September 2009 Creative Commons published a report titled, "Defining 'Noncommercial'". The report featured survey data, analysis, and expert opinions on what "noncommercial" means, how it applied to contemporary media, and how people who share media interpret the term. The report found that in some aspects there was public agreement on the meaning of "noncommercial", but for other aspects, there is wide variation in expectation of what the term means.
Change of basis matrix Updated +Created
The change of basis matrix is the matrix that allows us to express the new basis in an old basis:
Mnemonic is as follows: consider we have an initial basis . Now, we define the new basis in terms of the old basis, e.g.:
which can be written in matrix form as:
and so if we set:
we have:
The usual question then is: given a vector in the new basis, how do we represent it in the old basis?
The answer is that we simply have to calculate the matrix inverse of :
That is the matrix inverse.
Charge conservation Updated +Created
Charitable organization Updated +Created
Charles Bukowski Updated +Created
Video 1.
Something for the touts
. Source.
We have everything and we have nothing
And some men do it in churches
And some men do it by tearing butterflies in half
and some men do it in Palm Springs
Laying it into butter-blondes with Cadillac souls
This stuck to Ciro's mind for some reason. His brain just keeps completing the sentence, over and over:
Ciro Santilli does it in his computers and in his labs!
Charles K. Kao Updated +Created
Figure 2.
2009 Nobel Prize lecture
. Poor Charles was too debilitated by Alzheimer's disease to give the talk himself! But if you've got a pulse, you can get the prize, so all good.
Charles Simon Updated +Created
Basically it looks like the dude got enough money after selling some companies, and now he's doing cooler stuff without much need of money. Not bad.
Chart Updated +Created
Cheap oscilloscope Updated +Created
Video 1.
DIY Oscilloscope Kit (20$) VS Regular DS Oscilloscope (400$) by Great Scott (2016)
Source.
Video 2.
Hantek 6022BE Review by Adrian's Digital Basement (2022)
Source.
Chemical bond Updated +Created
Chemical company Updated +Created
Chemical compound Updated +Created
The definition does not include homonuclear molecules which is a pain.
Chemical process design Updated +Created
Video 1.
Computer Aided Simulation & Design in Chemical Engineering by Chemical Engineering Guy (2016)
Source. Interesting overview of the different types of modelling software used in chemical process design.
Video 2.
How to Design a Total Synthesis by Mike Christiansen (2013)
Source. Just a ultra quick hello world with some very basic ideas, but worth watching.
Video 3.
SuperPro Designer: Fermentation Simulation by LearnChemE (2012)
Source.
Chemical process design software Updated +Created
Video 1.
Process Simulation Software FREE Download - Aspen Hysys versus DWSim | COCO by Jeferson Costa (2020)
Source. Jeferson, a Brazilian from Petrobras, is the creator of the open source DWSim software, and in this video he gives a quick demo of his software and compares it briefly to aspen HYSYS, which appears to be the golden paid reference implementation.
Chemistry Updated +Created
Chemistry is fun. Too hard for precise physics (pre quantum computing, see also quantum chemistry), but not too hard for some maths like social sciences.
And it underpins biology.
Video 1.
100 Greatest Discoveries - Chemistry by the Discovery Channel (2005)
Source. Pretty good within what you can expect from popular science. The discovery selection is solid, and he interviews 3 Nobel Prize laureates, only one about stuff they invented, so you can see their faces. The short non-precise scenes of epoch are also pleasing. Part of 100 Greatest Discoveries by the Discovery Channel (2004-2005).
Chengyu Updated +Created
Chess UI Updated +Created

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