xavieralexandre

> They require a shielded room to increase the SNR.

Not anymore. That is exactly the purpose of Darpa Ambient program: https://www.darpa.mil/research/programs/atomic-magnetometer-...

Demo from 2022: https://www.youtube.com/watch?v=VTnIXWCBYTw

Thanks. I was mostly basing my answer on my experience with nautical charts, where declination corrections are typically uniform over relatively large areas and local anomalies are less of a concern. I hadn’t considered how much more variable the field can be in terrestrial use.

You are linking to the magnetic anomaly grid, which is primarily intended for geophysical research and modeling local variations.

For a basic compass app, you can rely on the World Magnetic Model (WMM) instead: https://www.ncei.noaa.gov/products/world-magnetic-model

From that, you can pre-compute a low-resolution declination grid. NOAA even provides one here: https://www.ngdc.noaa.gov/geomag/calculators/magcalc.shtml#i.... That’s only a few KB of data and requires just a simple declination subtraction based on lat/lon, similar to how it’s handled on nautical charts. This works fine as long as you stay away from the poles (and Alaska).

Some types of glue absorb a lot of the laser energy. There are dedicated plywood optimized for laser cutting https://n-e-r-v-o-u-s.com/blog/?p=6042

The article rightly points out the industrial impact of more powerful and compact lasers but I cannot wait for those PCSELs to reach the small workshop market. Having a cheap laser able to cut metal at home / small shops would be so useful (And sneakily dangerous as lasers are).

Most plywood is glued with phenolic glues whereas melamine glues will behave better with a laser: https://n-e-r-v-o-u-s.com/blog/?p=6042

He also did a nice post about a machine he built to test Blackberry pagers' radio reception: https://woodgears.ca/misc/rotating_machine.html

You are not forbidden at the Federal level to have fixed units.

But many states do indeed requires a permit to install fixed units. And have strict regulations such as self producing half of the electricity required by the installation.

Here are a few examples of such regulations:

- Geneva (the most strict state): https://www.ge.ch/installations-techniques-rafraichissement/...

- Fribourg: https://bdlf.fr.ch/app/fr/texts_of_law/770.1/art/16

- Vaud: https://www.vd.ch/fileadmin/user_upload/themes/environnement...

One of the side effect of such regulation is that many business and houses will use cheap non-fixed units with open door and windows instead of installing proper reversible heat pumps.

It looks like someone took the "Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway" sneakernet idea literally.

I love reading those articles about new materials. Since reading James Edward Gordon's The New Science of Strong Materials: Or Why You Don't Fall through the Floor (https://press.princeton.edu/books/paperback/9780691180984/th...), I’ve been trying to keep in touch with the development of new materials. Still, I find it hard to understand which materials get into production. You tend to read news about new materials when a press release is published (as it is a relatively discrete event), but rarely about the fact that an industry has progressively adopted a new material that it regularly uses in production. It is even worse if there isn't a corporation or institution behind it to promote it.

For example, I read many articles about Flash Bainite Steel (https://www.osti.gov/servlets/purl/1461193) in 2015, and I’d love to know if the industry has adopted this process. (I am especially curious about its potential use as tubing material for bicycle frame building).

Also the planet could well become greener with global warming but the issue is the rate of change. Even if the new growing conditions were great for some crops, evolving our entire agriculture and food regimen to them in a few decades is a huge ordeal.

Steam bending was and is still used for mass-produced furniture: https://en.wikipedia.org/wiki/No._14_chair

And there are also very interesting modern takes on bending wood such as compwood: http://compwood.com/processen/

The wood is heated and compressed longitudinally. Once cold it stays (super) bendable as long as it is still wet.

https://blog.lostartpress.com/2020/07/22/a-little-bit-about-...

I do it in practice! With light hills I climb at 25kph (Steeper hills, I can’t hit the limit), and go down at 30-35. Faster than the same length flat road along the lake.

I’m currently renovating a house and we live with a single wood (pellet) stove for the whole building. Living in a 16C home is surprisingly fine but the worst part is indeed the cold bathroom in the morning.

This reminds me of one of my favorite physics lessons in undergrad: classical mechanics are a limiting case of general relativity where v << c so that all terms with v/c can be neglected.

Dig a few meters and your soil will be 13C, a great starting point for your heat pump.

Wouldn’t you be able to have a heat floor heated by your wood? If wood is cheap where you live heating water with it is a nice upgrade from a basic wood stove.

The fact that each link is accompanied by a quick summary is a nice touch.

I wish more newsletters and link lists would do this.

http://www.pointer.io/archives/

Technically there is a mass of cold air that comes out of the fridge when you open the door. Keeping the door shot keeps this mass of air inside.

I expect bike and component prices to go down with wider adoption. Especially e-bikes. I was for example surprised to see that on my kids-towing e-bike in a hilly city I have to change front-disc-brakes pads approximately every 1'000km which, at 20€ a pair of disc-brakes pads in Switzerland, translates to approximately 0.02€ per km just for braking. Which at the end of the day is not an issue for me but seems SO expensive in comparison with a car.

I'm wondering if a workable idea would be instead of having pedestrian paths and bike lanes and wondering where new kind of vehicles should go to have different tiers of lane with different speed and weight limits.

For exemple:

* < 10 km.h^-1 & < 15 kilograms vehicle for pedestrian paths (Which would for exemple allow small kids to ride there).

* < 25 km.h^-1 < 30 kilograms for the bike lane equivalent.

* > 25 km.h^1 or > 30 kilograms on the road.

From a taxation point of view I'm under the impression that for a country such as France for example seniors are gonna get _on average_ way more benefits during their pension than the equivalent of their lifetime contribution. Mainly due to demographics and life expectancy evolution. And also for home owners due to the housing market. I do not think this should be a reason to limit the access to university to seniors though. What better use of life to increase and share knowledge, maybe even contribute to it. It would be such a low point for society to bar access to knowledge only because it is not profitable.

I like the Illy [1] book on the subject. It is mainly about Italian espresso though and less representative of 3rd wave brewing.

[1] https://www.elsevier.com/books/espresso-coffee/illy/978-0-12...

Decent Espresso makes a great machine to control espresso brewing parameters [1]

My favorite feature is the ability to give it different target curves to follow for different parameters during successive phases of the extraction. You can for example ask the machine to pre-infuse for x seconds at a given pressure and then switch to flow profiling and have the machine try to adjust the pressure to follow a pre-set flow curve.

It makes it a powerful platform to isolate experimentally the contributions of several brewing variables.

[1]: https://decentespresso.com/overview

> The costs of nuclear power have never appropriately included the costs of disposal and handling of wastes

Of course, they do:

- Hinkley Point: http://www.world-nuclear-news.org/NP-Hinkley-Point-C-contrac...

- France [French]: http://www.sfen.org/sites/default/files/public/atoms/files/n...

- Switzerland [French]: http://www.swissnuclear.ch/fr/couts-_content---1--1050.html