Microwave source by Ciro Santilli 40 Updated 2025-07-16
Microwave only found applications into the 1940s and 1950s, much later than radio, because good enough sources were harder to develop.
One notable development was the cavity magnetron in 1940, which was the basis for the original radar systems of World War II.
Microwave oven by Ciro Santilli 40 Updated 2025-07-16
Video 1.
How Microwaves Work by National MagLab (2017)
Source. A bit meh. Does not mention the word cavity magnetron!
Video 2. . Source. Cool demonstration of the standing waves in the cavity with cheese!
Not done yet as of 2020! Will be done one day for sure.
The most notable exception is the borrowing of 3d-orbital electrons to 4s as in chromium, leading to a 3d5 4s1 configuration instead of the 3d4 4s2 we would have with the rule. TODO how is that observed observed experimentally?
Tried a quick port to SQLite to get rid of annoying local databases for development, but failed, at c1c2cc4e448b279ff083272df1ac50d20c3304fa
npm install sqlite3 --save-dev
and
{
  "type": "sqlite",
  "database": "db.sqlite3",
  "entities": ["src/**/**.entity{.ts,.js}"],
  "synchronize": true
}
then:
npm start
fails with:
DataTypeNotSupportedError: Data type "timestamp" in "ArticleEntity.created" is not supported by "sqlite" database.
Attempt to hack it:
--- a/src/article/article.entity.ts
+++ b/src/article/article.entity.ts
@@ -20,10 +20,10 @@ export class ArticleEntity {
   @Column({default: ''})
   body: string;

-  @Column({ type: 'timestamp', default: () => "CURRENT_TIMESTAMP"})
+  @Column({ default: () => "CURRENT_TIMESTAMP"})
   created: Date;

-  @Column({ type: 'timestamp', default: () => "CURRENT_TIMESTAMP"})
+  @Column({ default: () => "CURRENT_TIMESTAMP"})
   updated: Date;
and after that it seems to run.
I can signup and login, terrible error reporting as usual, make sure to use long enough usernames/passwords.
However, article creation fails with:
Unhandled Rejection (TypeError): Cannot read property 'slug' of undefined
Video 1.
Fabry Perot Interferometer by JFC UCL (2016)
Source. Description only, reasonable animations. Considers the case of two nearby beam splitters.
Video 2.
Fabry-Perot Introduction by Williams College Physics (2020)
Source.
Shows a working device. Confocal optical cavity, one of the mirrors scans back and forward moved by a piezoelectric motor, this is called a "scanning Fabry-Perot interferometer".
Does not produce an interference pattern, only an on/off blob, which is then fed into an oscilloscope for analysis. The oscilloscope shows both the mirror displacement (which is given by a voltage) and the light detector output.
Video 3.
Aligning a Scanning Fabry-Perot Interferometer by University of South Florida (2016)
Source. Very detailed, and shows of some nice equipment and techniques.
Also webpack and Babel, looks promising!
As of 2021, last commit from 2017.
Running:
git clone https://github.com/Codaisseur/feathersjs-react-redux-ssr
cd feathersjs-react-redux-ssr
npm install
failed on Ubuntu 20.10 Node.js v14.15.3 with:
../src/create_string.cpp:17:37: error: no matching function for call to ‘v8::String::Utf8Value::Utf8Value(v8::Local<v8::Value>&)’
   17 |   v8::String::Utf8Value string(value);
      |                                     ^
Likely similar bullshit from: stackoverflow.com/questions/50111688/node-sqlite-node-gyp-build-error-no-member-named-forceset-in-v8object because the Node.js version is too new.
If I try nvm install v10
I Google error messages until reaching:
diff --git a/gulpfile.js b/gulpfile.js
index b931e06..24d2cc8 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -14,34 +14,34 @@ gulp.task('css', function() {
            .pipe(gulp.dest('./dist'))
 })
 
-gulp.task('css:watch', ['css'], function() {
+gulp.task('css:watch', gulp.series('css', function() {
   gulp.watch('app/styles/**/*.sass', ['css'])
-})
+}))
 
 gulp.task('moveAssets', function() {
   return gulp.src('./app/assets/**/*')
              .pipe(gulp.dest('./dist/assets'))
 })
 
-gulp.task('build:revAssets', ['css', 'moveAssets'], function() {
+gulp.task('build:revAssets', gulp.series('css', 'moveAssets', function() {
   var rev = new $.revAll()
   return gulp.src('./dist/**/*')
              .pipe(rev.revision())
              .pipe(gulp.dest('./dist/public'))
              .pipe(rev.manifestFile())
              .pipe(gulp.dest('./dist'))
-})
+}))
 
 gulp.task('build:cpServer', function() {
   return gulp.src('./app/**/*.{js,ejs}')
              .pipe(gulp.dest('./dist/server-build'))
 })
-gulp.task('build:revServer', ['build:cpServer'], function() {
+gulp.task('build:revServer', gulp.series('build:cpServer', function() {
   var manifest = gulp.src('./dist/rev-manifest.json')
   return gulp.src('./dist/server-build/{components,containers}/**/*')
              .pipe($.revReplace({ manifest: manifest }))
              .pipe(gulp.dest('./dist/server-build'))
-})
+}))
 
 gulp.task('build', function() {
   runSequence('build:revAssets', 'build:revServer')
diff --git a/package.json b/package.json
index bcb29c3..86bd593 100644
--- a/package.json
+++ b/package.json
@@ -67,7 +67,7 @@
     "redux-thunk": "^0.1.0",
     "request": "^2.79.0",
     "rewire": "^2.3.4",
-    "run-sequence": "^1.2.2",
+    "run-sequence": "^2.2.1",
     "serve-favicon": "^2.3.2",
     "socket.io-client": "^1.7.2",
     "superagent": "^1.4.0",
@@ -86,16 +86,16 @@
     "concurrently": "^2.0.0",
     "cross-env": "^1.0.7",
     "enzyme": "^2.3.0",
-    "gulp": "^3.9.0",
+    "gulp": "^4.0.2",
     "gulp-autoprefixer": "^3.1.0",
     "gulp-load-plugins": "^1.2.0",
     "gulp-rev": "^6.0.1",
-    "gulp-sass": "^2.1.1",
+    "gulp-sass": "4.1.0",
     "gulp-sourcemaps": "^1.6.0",
     "jsdom": "^7.0.1",
     "mocha": "^2.4.5",
     "nock": "^2.17.0",
-    "node-sass": "^3.4.2",
+    "node-sass": "^5.0.0",
     "nodemon": "^1.6.0",
     "react-addons-test-utils": "^15.3.2",
     "react-transform-catch-errors": "^1.0.0",
and the next problem is: stackoverflow.com/questions/48513573/gulp-error-gulp-hastask-is-not-a-function
MongoDB-based.
So once you install MongoDB, run with:
MONGODB_FEATHERS_REALWORLD=mongodb://localhost:27017/mydb npm start
Tests can be run with:
MONGODB_FEATHERS_REALWORLD=mongodb://localhost:27017/mydb npm run test
but there were 10 failures and 55 passes: github.com/randyscotsmithey/feathers-realworld-example-app/issues/3
hello_world_len points to the special st_shndx == SHN_ABS == 0xF1FF.
0xF1FF is chosen so as to not conflict with other sections.
st_value == 0xD == 13 which is the value we have stored there on the assembly: the length of the string Hello World!.
This means that relocation will not affect this value: it is a constant.
This is small optimization that our assembler does for us and which has ELF support.
If we had used the address of hello_world_len anywhere, the assembler would not have been able to mark it as SHN_ABS, and the linker would have extra relocation work on it later.

Pinned article: 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!
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
  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:
    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 2.
    You can publish local OurBigBook lightweight markup files to either https://OurBigBook.com or as a static website
    .
    Figure 3.
    Visual Studio Code extension installation
    .
    Figure 4.
    Visual Studio Code extension tree navigation
    .
    Figure 5.
    Web editor
    . 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