Random links #17

Written on 7 October 2019, 02:49pm

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Electric planes

Air travel is bad for the planet—and travelers may finally be getting the message.
The change in mindset is due to increasing awareness of the issue thanks to attention-grabbing protests, like when activist group Extinction Rebellion shut down Heathrow Airport and climate warrior Greta Thunberg sailed across the Atlantic in a zero-emissions yacht to speak at the UN’s climate summit.

Does flight shaming work?

Solution? Hybrid or full electric planes. Also tested by NASA.

Heavyside, from Kitty Hawk is really silent and has a range of about 100 miles

Radiation in space is a big deal

If we want to prepare astronauts to fly to Mars, then we have a lot of problems to solve when it comes to health and well being. There are both psychological (isolation, confinement, sleep disturbance, etc) but also physiological (micro-gravity long time effects, radiation) factors to overcome. One of the most important is the radiation.

Radiation on Earth is about 4.6 mSv/year. On the Moon – 300/400x. On Mars – 1000x.

How can we reduce the radiation impact? Medical selection of the most resistant individuals, shielding (the ISS has 3 highly shielded areas) and medication. Hibernation is also an option, not explored yet.

Radiation sensitivity decreases with age. A teenager is 2 times more sensitive than a 30-years old adult, which is in turn 2 times more sensitive than a 50-years old.

Space travel affects the astronauts’ immune system. Various factors play a part in this process, i.e. weightlessness, cosmic radiation, isolation and the inevitable stress. At the request of European, American and Russian space agencies, SCK•CEN tests the blood of astronauts when they return from a long space mission. We perform analyses using advanced biochemical and molecular techniques.
Long-term exposure cannot be avoided during long distance missions, e.g. to Mars – for which the return flight takes 18 months. Sensitivity to cosmic radiation varies considerably between people, and consequently also between astronauts. 

The Belgian Nuclear Research Centre

Time matters

The Tesla dashcam writes its rolling clips in the /recent folder. The manually saved clips are stored in the /saved folder. Recently Tesla introduced the Sentry mode, which automatically saves events when the car is parked (ex. a person or a car is passing by).

The Tesla engineers thought that it’s appropriate to save these clips not in a dedicated folder (like /sentry), but in the same /saved folder where the manual clips are saved.

The outcome? When I want to look for a video that I manually saved, I have no easy way to find it. Sentry mode produces a huge number of videos, sometimes 10 videos for a half an hour spent in a busy parking. Finding the right folder among literally hundreds of other folders is like finding a needle in a haystack.

Compare this to the following bit:

One day Jobs complained to Larry Kenyon (the engineer of the Macintosh OS) that it was taking too long to boot up. Kenyon explained why reducing the boot-up time wasn’t possible, but Jobs cut him off: “If it would save a person’s life, could you find a way to shave 10 seconds off the boot time?”. He then showed on a whiteboard that if the Mac had five million users and it took 10 seconds extra to turn it on every day, that added up to 300 million or so hours a year — the equivalent of at least 100 lifetimes a year. After a few weeks, Kenyon had the machine booting up 28 seconds faster.

Steve Jobs Insane Productivity Secrets

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