Okay so here’s the deal, I was going to learn 1 new topic a day in September, but quickly realised… topics are either pointlessly small or overwhelmingly big. So, here you go, have a few days of topic notes!

Banner image is from this excellent guide to UK house wiring.

Jekyll build process

  • What do I want to learn? How does Jekyll convert my list of posts and templates into… an actual site? Is it just convert markdown, glue it together, and done?
  • How much do I know already? Despite making a theme used on various sites… not much! I know how to use it, and how to customise it, but not about how it actually compiles, how the automatic rebuilding works, or anything else.

Building

Luckily, Jekyll has an entire page1 dedicated to how the build process works! The build process is just a series of steps running in order, as you’d expect, some with substages:

  1. Setting up plugins (e.g. initialising).
  2. Reading source files.
  3. Running generators2: Generate dynamic variables / content based on site contents, e.g. pages for article categories, or a sitemap, or an RSS feed.
  4. Rendering templates (each substage is optional, depending on file extension, front matter, and content):
    1. Interpreting the “Liquid”3 code.
    2. Running converters (e.g. Markdown -> HTML, SASS -> CSS)4.
    3. Populating layouts (e.g. putting a post’s content into the post.html template).
  5. Saving generated files.

Other

  • Incremental regeneration: Jekyll’s documentation has a dedicated page for incremental regeneration, and it works how you might guess: By keeping track of last modified dates (and which files feed into which others) in a .jekyll-metadata file. Simple. However, I don’t actually use this, I use…
  • Watch: Enabled by default, and no new release in 5 years(!)5. Whilst I had intended to learn how this actually works, it’s just a short Ruby script6 so not much to look at.

Interestingly, the very first item on Jekyll’s “Philosophy” page7 is “No Magic”, with the explicit intention of users (e.g. me) being able to figure out how it works. Convenient!

Jekyll is not magic. A user should be able to understand the underlying processes that make up the Jekyll build without much reading.

Perhaps this shouldn’t have been a surprise, since I’ve regularly added plenty of new features to my minimaJake theme and things just… kinda make sense? I can copy the existing template, copy existing plugins, all because the project aims for simplicity and obviousness.

Conclusion

Well, Jekyll ultimately is just a series of simple steps! However, the implementation of plugins, converters, and styling seems to have been very intentionally designed for extensibility, making users’ lives as easy possible. Nice.

Fruit tree growing

  • What do I want to learn? I have a few small fruit trees in my garden, and they’re doing whatever they want. Should I be helping them somehow? Pruning them?
  • How much do I know already? Essentially nothing. I remove any dead fruits, and sometimes trim the trees if they’re reaching too far towards each other, but I don’t know if this is correct.

Notes

  • They need a lot of watering8! I haven’t been giving them any besides what they occasionally catch when I water the lawn (not at all this year).
  • Similarly, I should make sure they get some bonus nutritious garden compost9, or the chicken manure pellets I found in my garage!
  • I should also sometimes clear some space around the bottom, so they get the compost nutrients not the grass they’re growing in.
  • “Thinning” is a thing! By getting rid of some fruit in May-ish when they’ve just started appearing, the tree can put all its energy into fewer, bigger fruits.
  • Maintenance of the tree’s shape seems pretty flexible. Prune in winter if you want MORE tree, prune in spring & summer if you want to keep it about the same size10. I’ll do the latter.

Conclusion

I need to look after my trees better! Next spring I’m looking forward to thinning out the fruit, and pruning the trees so they’re a less chaotic shape. Hopefully it’ll help provide more plums and apples to eat, I definitely noticed having fewer this year than the one before.

However, it really isn’t that complicated. Like with seemingly everything else in the garden, it just needs a bit of effort at the right time. If only I was retired and could do a little gardening daily..!

F1 Aerodynamics

  • What do I want to learn? What does aero / aerodynamics actually mean? What is it trying to do? How?
  • How much do I know already? Well, I know that the car wants to be “pushed” down to maximise tyre grip on the track. I also know it wants to minimise air resistance and have air flow smoothly over. However, I don’t understand how tiny changes to the overall shape can have such a significant impact, or what “good” aero looks like. The little I do know is from SuperfastMatt.

Notes:

What is lift / downforce?

The air passing under the wing has further to travel than the air passing over the top surface. This causes the air under the wing to accelerate, resulting in a drop in air pressure, this creates a difference in pressure between the upper and lower surfaces. This difference essentially means the wing is pushed down by the higher pressure above, generating what is known as downforce.11

Parts of car aerodynamics:

  • Front wing guides the air to the rest of the car12
  • Front wing end plate directs air around the wings, reduces turbulence, improves grip
  • Rear wing creates downforce as the air flows over13
  • Floor creates pressure difference between top and bottom of car, generating downforce to “pull” the car downwards, improving grip therefore speed
  • Diffuser (the odd shape at the bottom back) guides the air from under the car to smoothly rejoin the air from the top of the car, whilst stopping any other air from getting under the car. This results in the entire car behaving like one big wing!
  • Brake duct gets air into the wheels to cool the brakes, at the expense of smooth aerodynamics
  • Side pods are the bulky side bits in newer cars (due to changes in regulations) that essentially “allows all the cool air pressure magic to be kept under the car and stabilise the ground effect” by controlling how air behaves at the floor’s edge14

How to study:

  • Aero rake is the metal grid with “Kiel probes” to measure airflow15
  • Flow visualisation paint is fluorescent powder + oil that changes colour, again to measure airflow. Works by oil evaporating under airflow, so look for separated lines etc16
  • Wind tunnel uses a scale model of the car, and gets super detailed data. Limited time allowed though, depending on last year’s performance17!
  • Simulations using “Computational Fluid Dynamics” for super-intense calculations of airflow18

Book publishing

  • What do I want to learn? How do somebody go from writing their first fiction or non-fiction document, to it becoming a physical book in stores? I know places like Amazon let people essentially self-publish, but I’m more interested in the traditional, physical book industry.
  • How much do I know already? Bits and pieces. I think you need an agent, and later on you’ll have an editor who will help tidy it up. However, most of what I know is from Stephen King, Terry Pratchett, or Isaac Asimov who wrote about the process when they were already successful.

Notes:

The overall process is19:

  1. Author finds an agent who likes their manuscript (draft), similar to other entertainment industries.
    • The author submits their finished manuscripts to agents, and wait 1-3 months for a reply.
    • The agent typically only reads more than a couple of paragraphs20, and might want a cover (query) letter and/or a few pages21.
  2. Agent offers book to editors at publishers.
    • This is where the contract negotiation process happens.
    • Sometimes there’s multiple interested editors, so possible bidding war.
  3. Editor “buys” the book (agrees contract), edits the content, grammar, etc. Usually takes 18 months(!). They are generally responsible for the whole process22.
  4. Once the content is ready, the production team prepares all the next steps for making it a physical / ebook.
    • The design team works on a cover.
    • There are also copy-editors, proofreaders, typesetters, etc23.
  5. The sales team pitches the book to everywhere that might be interested. So, supermarkets, Amazon, independent bookshops, etc.
    • Similarly, the rights team might sell it to foreign publishers, sell translation rights, sell movie / TV rights, etc.
    • The audiobook team will obviously… make the audiobook. This is a whole process since you need casting, recording, editing, etc24.
  6. Now the book is actually available, the marketing and publicity teams do all the advertising, partnerships, events interviews, about what you’d expect.
  7. Done!

Seems like the process is actually straightforward! From the author’s perspective once an agent likes your work, it seems that the majority of the effort is on the agent & publisher’s side.

Of course, before that you’ve got to write an entire book, one that an agent will want to work with you on. Easy..!

Household electrics

  • What do I want to learn? The basics! How do circuits work in UK houses, how do fuses work, how dangerous is household electrical power, anything really.
  • How much do I know already? Well, I studied physics at school and read plenty of news about electronics, watch the occasional device teardown etc… but I always forget the basics! So, I confidently know zero, but tentatively know more.

Notes:

Fuse boxes:

  • When too much power goes through a fuse, it melts, protecting the actual consumer of the electricity.
  • However, every “fuse box” I’ve owned is actually an “electrical consumer unit”, with switches that flip instead of melting25! Interesting how the old name has stuck.
  • Some circuits have “RCD protection”26, which turns off the circuit immediately when electrical current is unexpectedly reaching earth (e.g. via your body!).
    • This drastically reduces the risk from accidentally touching a live wire, or an appliance’s metal case becoming live.
    • In my house, I have quite an old unit so only sockets & appliances have RCD protection. However, lights and other things have no protection, so random wires in the walls are dangerous.
    • Modern houses have all circuits RCD protected, which an electrician previously recommended along with replacing the box itself. Now I know what RCD does, I agree!

Electrical circuits:

  • Each “switch” in the fuse box controls a collection of electricity consumers. For example upstairs sockets, or kitchen appliances.
  • Sockets are usually wired up in a big “loop”, often in a loop per floor. Kitchens often have their own since they have higher power consumption appliances27.
  • Lights are also usually in a “loop”.

Wires:

  • There are 2 wiring colour schemes, an “old” one (pre-2006), and a “new” one28:
    • Live: Brown (formerly red), carries the current from the power supply to the appliance.
    • Neutral: Blue (formerly black), carries the current from the appliance back to the power supply.
    • Earth: Green / yellow (or no sleeve), “catches” current through the fuse in case something goes wrong29.

References

  1. https://jekyllrb.com/docs/rendering-process/ ↩

  2. https://jekyllrb.com/docs/plugins/generators/ ↩

  3. https://shopify.github.io/liquid/ ↩

  4. https://jekyllrb.com/docs/plugins/converters/ ↩

  5. https://github.com/jekyll/jekyll-watch ↩

  6. https://github.com/jekyll/jekyll-watch/blob/master/lib/jekyll/watcher.rb ↩

  7. https://jekyllrb.com/philosophy/ ↩

  8. https://www.ashridgetrees.co.uk/advice/essential-aftercare#:~:text=All%20fruit%20trees%20need%20a%20steady%2C%20consistent%20even%20supply%20of%20moisture. ↩

  9. https://www.rhs.org.uk/fruit/fruit-trees/feeding-and-mulching ↩

  10. https://www.woodlandtrust.org.uk/blog/2018/02/when-to-prune-fruit-trees/ ↩

  11. https://www.racecar-engineering.com/tech-explained/diffusers-engineering-basics-aerodynamics/ ↩

  12. https://racingnews365.com/aerodynamics-f1#:~:text=Front%20wing%20and%20rear%20wing ↩

  13. https://www.neuralconcept.com/post/formula-1-multiple-connected-components-and-long-range-aerodynamic-correlations ↩

  14. https://www.reddit.com/r/F1Technical/comments/1aq53w6/why_are_sidepods_so_important_in_the_current/ ↩

  15. https://www.motorsportmagazine.com/articles/single-seaters/f1/what-is-an-f1-aero-rake/ ↩

  16. https://www.formula1.com/en/latest/article/testing-explained-rob-smedley-on-flow-vis.7nU2VePGlVrhIGa8wgCoLE ↩

  17. https://racingnews365.com/how-many-wind-tunnel-hours-do-f1-teams-have-in-2024 ↩

  18. https://en.wikipedia.org/wiki/Computational_fluid_dynamics ↩

  19. https://www.publishers.org.uk/about-publishing/how-publishing-works/ ↩

  20. https://www.reddit.com/r/writing/comments/16kdue1/how_much_publishersagents_will_really_read_of_the/ ↩

  21. https://www.reddit.com/r/writing/wiki/publishingfaq#wiki_-how_do_i_get_started_on_the_traditional_publishing_path_for_novel-length_fiction.3F ↩

  22. https://www.publishers.org.uk/about-publishing/careers/commissioning-editor/ ↩

  23. https://www.publishers.org.uk/working-in-production-with-philippa-fiszzon/ ↩

  24. https://www.publishers.org.uk/about-publishing/careers/audio-publisher/ ↩

  25. https://excelelectrician.co.uk/fuse-box-replacement/ ↩

  26. https://wiki.diyfaq.org.uk/index.php/RCD ↩

  27. https://wiki.diyfaq.org.uk/index.php/House_Wiring_for_Beginners#Ring ↩

  28. https://www.skillstg.co.uk/blog/guide-to-electrical-wiring-colours-in-the-uk/ ↩

  29. https://www.bbc.co.uk/bitesize/guides/z3fsmsg/revision/2 ↩