donquichotte

I wonder why this is being downvoted.

The War of Art is undoubtedly a self-help book, and so is How to Make Friends and Influence people. Both contain little more than trivial platitudes IMO. I have not read the other books, but from the abstracts it looks like several more can be considered self-help books.

I was hoping for hands-on books like "The Art of Electronics" by Horowitz & Hill or similar.

This is different though.

It looks like they are using transcranial stimulation, i.e. putting electrodes on both sides of your head and running a current through it, resulting in what I assume to be a quite homogeneous current distribution throughout brain tissue.

RF waves' tissue penetration is stronger at the surface of a conductor, see Skin Effect.

EDIT: substituting the frequency in [1], we arrive at ~9mm skin depth for 918MHz.

[1] http://www.sgoc.de/Download/skin_effect.pdf

> Beyond that, you're inferring threading into the problem.

That's what I was thinking. There are no threads in the example.

Don't forget the commute either. Suddenly you're clocking in 12h days without even noticing.

Can anyone shed light on what MITRE Corporation is and what kind of systems they build?

I could not find that information from Wikipedia or the official web page.

> do you have any idea what part(s) are failing so quickly? The rotors, the motors, the battery?

My bet is on the power electronic semiconductors, mostly MOSFETs, in the motor controllers. Life time of these components decreases exponentially with the temperature difference they see in the semiconductor junction, i.e. the difference between hot (current is flowing, heating the junction with a power of I^2 * R_ds_on) and cold.

To make this deltaT_junction small, you need to choose big components, but at the same time you want to save weight, which is fundamentally at odds with overdimensioning everything.

Myfordboy is an excellent mechanic and engineer, and one of my favourite youtube channels.

VOG [1] runs another channel that does a lot of (artistic) metal casting with mostly 3D printed positives, called "lost PLA casting".

He uses casting plaster and built his own vacuum chamber and furnace to improve the quality of his casts.

[1] https://www.youtube.com/channel/UCkEYj8wtK3aEW8vSGhlB43g

This is intense, and I don't listen to classical music regularly.

Wow, I think you are right. 422 youtubers with >10e6 subscribers [1], 536 people have been to space [2].

[1] https://socialblade.com/youtube/top/500/mostsubscribed [2] https://en.wikipedia.org/wiki/List_of_space_travelers_by_nam...

Written in 1997. My picture of RMS is slowly changing from religious zealot to apocalyptic prophet.

The STM32F7 and H7 have data and instruction cache, IMO blurring the line between microcontrollers and SoCs.

Instagram does something similar if it detects that you are on mobile. A huge banner advertising their app is displayed, and the [x] in the top right corner is almost impossible to hit.

7 years ago I worked for a company that builds pumps. I spent days on http://www.druckverlust.de/Online-Rechner/

I have no experience in building a business, but some years ago I was in a quite similar situation - working a draining, non-fulfilling job where I felt stuck.

Quitting and subsequently going on a 4 month motorcycle trip through Central Asia now feels like one of the best decisions of my life.

You are young, well educated, unhappy and working at the same company since you are 24. If your endeavor does not work out, you have will probably have a good chance of finding a decent new job. I believe that subjecting yourself to a new environment and new challenges from time to time reinvigorates your life and make you a happier person.

It's sad that this "article" is not going more in-depth.

What bugged me most was:

> [...] it matters where the electrons going into an EV come from; coal-fired power is [...] less than 40% efficient on average. [If ...] we lost 6% in transmission, it would still add up to only 10 million barrels a day in oil terms. The efficiency gain is overwhelming.

No! What about losses in the electric grid? What about losses in the battery? As far as efficiency is concerned, electric cars are just as bad as ICE cars, given their electricity comes from thermal power plants. Plus, a lot of rare earths are required to manufacture them, mainly for the permanent magnets in the synchronous motors and the batteries.

You can't go wrong with a nice glass of Moloko Plus.

In my experience, specs are omitted in technical articles IFF somebody is trying to hide something. Like super short flight time.

The MIT battery primer [1] states a specific energy of 150Wh/kg for Li-Ion cells. 150kWh would therefore weigh 1000kg.

Even at double the specific energy, the battery would still weigh in at 500kg, almost 80% of the maximum takeoff weight.

If there is a future for electric airplanes, it is going to be in fixed-wing applications.

[1] http://web.mit.edu/2.009/www/resources/mediaAndArticles/batt...

I was always under the impression that integrating unknown biases in gyroscope and accelerometer measurments is the main issue with dead reckoning.

Today I am convinced that attitude errors are the far bigger issue, since they will make you misinterpret gravity as genuine acceleration.

Even with a 1° error in your pitch estimate, you will start integrating 9.81ms^-2*cos(1°) = 0.17ms^-2 as a forward acceleration. Within one minute, you are 308m off already. This is the real issue with dead reckoning IMO.

Agreed! And every component is highly complex, i.e. the design of the probe [1], or object tracking in videos. While the author is obviously standing on the shoulders of giants, he appears to be pretty tall himself.

[1] https://interferencetechnology.com/diy-near-field-probes-pre...

> Not great statistical support. I still rely on Seaborn for quick visualization that needs to fit a linear regression.

Why does a plotting library need support for statistical analysis? I always think of manipulating data and visualizing it as orthogonal disciplines.

Honestly, I think this should be quite doable. These guys [1] built a pump based on a stepper motor and an arduino, in order to replace expensive peristaltic laboratory pumps.

[1] https://www.instructables.com/id/Open-Source-Peristaltic-Pum...

This has been bothering me for a long time.

Many formerly communist countries, e.g. Vietnam, have unleashed the purest form of capitalism possible, where positive feedback loops make the rich grow richer and the poor grow poorer.

No labor laws, corruption and salary ratios of 1:1000 within one company - it would be a true nightmare for the ideological socialist elite of the early 1900 to see what has become of their dream of equality.

Would you mind sharing details (or rough descriptions) of the shipped products? Or a broad category, i.e. "pace makers" or "motor controllers"?

Were these "strict policies" licensing issues? Or coding standard issues? IMO these issues are orthogonal to ease of integration.

Writing a simple driver for say an I2C sensor is quite doable. However, getting a driver into mainline requires conformity both in terms of licensing and in terms of coding standards for the whole library, including 3rd party code.

We use it at my company for several products. There is something magical about running a lightweight OS on a Cortex-M4F or Cortex-M7. It is how I imagine the early Linux days.

You get to write device drivers and dig into the OS internals. There is even a port of the uIP TCP/IP stack that can be used with development boards such as the Nucleo-144.

Fair point. The same thing applies to differentiation, where e.g. computing analytic Jacobians can be useful to save precious CPU cycles in embedded control systems.

Symbolic integration requires an accurate model of the system, whereas you can throw numerical methods at most problems and get results that are good enough. If you worry about your satellite falling down you can always try energy-preserving integrators.

I would wager the guess that most PID controllers, arguably the most common application of numerical integration, work just fine with just basic forward Euler integration.

The Abstract is a good summary. I am unsure how useful this is today. We now have battle tested numerical libraries that use Runge Kutta and similar to solve ODEs.

Abstract: SIN and SOLDIER are heuristic programs written in LISP which solve symbolic integration problems. SIN (Symbolic INtegrator) solves inde-finite integration problems at the difficulty approaching those in the larger integral tables. SIN contains several more methods than are used in the previous symbolic integration program SAINT, and solves most of the problems attempted by SAINT in less than one second. SOLDIER (SOLu-tion of Ordinary Differential Equations Routine) solves first order, first degree ordinary differential equations at the level of a good col-lege sophomore and at an average of about five seconds per problem attempted. [...]

What I really admire is people who manage to do all of it: start projects, finish them, and produce beautiful code that is simple to reason about.

Whenever I feel bad, sad or just in need on some enlightenment, I go to https://github.com/fogleman and browse Michael's repos.

Parent's last sentence gives me hope it should be OK, at least for the heart.

What I can surely say is that I have never been feeling better and healthier than since I started running long distances at 30.