Today I Learned

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Today I learned that cleaning a white hat can be done with bleach cleaner, but it’s important to rinse it before wearing it again. I also discovered that "oyster veneering," a woodworking technique from the late 1600s, is experiencing a minor revival despite its labor-intensive nature. Additionally, I learned that the factorial of 23 (23!) equals 25,852,016,738,884,976,640,000, which interestingly has 23 digits, a unique coincidence among factorials. I found out that medical specialists often spend less than 10 minutes with patients, and that watching TV can contribute to weight gain. Other insights included the fact that a kiss can transfer around 80 million microbes, and that bureaucracy can sometimes hinder employment opportunities. The discussion also touched on various trivia, such as the emotional sensitivity of barn owls and the complexities of gravitational lensing around black holes.
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  • #5,973
TIL that a horsehair rope circle won't protect me from rattlers, sidewinders or indeed any kind of North American snake :smile:

 
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  • #5,974
Swamp Thing said:
TIL that a horsehair rope circle won't protect me from rattlers, sidewinders or indeed any kind of North American snake :smile:
Sure. you forgot your snake tinfoil hat!

 
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  • #5,975

TIL of the cultural traditions of wild boars.

I had a neighbor who raised a wild boar as a pet. The little guy was friendly. As an adult pig he probably weighted about 300 or 400 pounds. His way of saying hello was to slobber on your shoes and then urinate on them. Wearing rubber garden boots was the remedy. -- 568843daw
 
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  • #5,978
Nice little video of the pillars of creation in 3D using JWST and Hubble images.

 
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  • #5,979
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  • #5,980
BillTre said:
TIL that RNA may be used to control pests.
Tests are being planned for a potato insect pest and possibly for the mite that attacks honey bees.
Seems like an excellent idea. I learned something. I really should get up to date with biochemistry.

BillTre said:
Why are they not doing it at the big wave place in Portugal?
Nazare doesn't break in the summer. Even if it did, it is a gargantuan pile without much shape. You can't get tubed there. You can't do any sort of maneuver. You can't do anything but run to the shoulder to get out of the danger. Even if you could it's a tow-in wave, which quite rightly isn't allowed in tournaments.

Nazare is dangerous : the wave broke a man's back. But Teahupo'o is perhaps equally so. It's name means something like "the place of broken skulls." Maya Gabeira almost drowned there after she couldn't kick out of the wave. At a women's tournament both surfers declined to take off during their heat. The event organizers angrily told them to get back out there. One of the two took off, was injured, and had to withdraw, so the other won by default without ever having surfed the wave.

As long as we are on this topic, world champ Kelly Slater said the most dangerous waves are Pipeline and Mavericks. However there are more dangerous waves. Indeed there are waves that are almost guaranteed to be fatal, but no one surfs them. Where do you draw the line?


 
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  • #5,981
Hornbein said:
TIL of the 1981 coup attempt in Spain.

https://en.wikipedia.org/wiki/1981_Spanish_coup_attempt
M.Y.A. I.L. (Many years ago, I learned) :
The a description about the event was later fit to the rhythm of Tanguillo, with lyrics, and this *can be found on YouTube.

* change this to "could" be found, since I am trying to search for one of them on YouTube and so far am unable to find one.

Okay I found one of them:
 
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  • #5,982


This would seem to correct for tilting, but not for horizontal movements of the ship.
 
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  • #5,983
BillTre said:


This would seem to correct for tilting, but not for horizontal movements of the ship.

I have never had sea sickness but that clip made me a little woozy!
 
  • #5,985
How much can roof-mounted bicycles on a following team car reduce cyclist drag?

This principle of the upstream effect suggests that the larger the body riding behind a cyclist, the larger the aerodynamic benefit for this cyclist will be. Therefore, researchers studied the effect that a following team car, as present during individual time trials, could have on the drag of the cyclist (Blocken and Toparlar, 2015). CFD simulations, validated with WT tests, demonstrated the large overpressure bubble in front of the car (Fig. 1), and revealed that the drag reduction for a time trial cyclist by a following team car at 1, 3, 5 and 10 m could go up to 13.7, 3.7, 1.4 and 0.4%, respectively, potentially providing several seconds of time gain over a typical individual time trial of a few tens of kilometres, compared to a cyclist followed by a team car at 25 or 30 m. Based on this research, the International Cycling Union (UCI) in 2023 decided to raise the minimum distance between a cyclist and the following team car from 10 m up to 25 m (International Cycling Union, 2023), thereby referring to the scientific study by Blocken and Toparlar (2015).

1-s2.0-S0167610524000862-gr1.jpg

However, this previous work on the aerodynamic benefit for a cyclist by a following team car did not consider the potential additional aerodynamic benefit by the bicycles that are typically mounted on the roof of such a team car. Fig. 2 shows four photographs of the individual time trial in the Tirreno-Adriatico in 2022, where figures a–d show team cars with 10, 4, 2 bikes and only 1 bike on the roof, respectively. On the one hand, this suggests that at that time, there was no consensus in the professional cycling community about the potential benefit by stacking many bicycles on the roof of the team car. On the other hand, a single cyclist in a single individual time trial would certainly not need ten spare bicycles. This suggests that at least one team was aware of the potential aerodynamic benefit by stacking multiple bicycles on the team car roof. However, time trial bicycles are designed to be as aerodynamic as possible, so one could question whether and to what extent these roof-mounted bicycles, when oriented in the riding direction as shown in Fig. 2, provide an extra upstream “push effect” for the cyclist.

1-s2.0-S0167610524000862-gr2.jpg

However, a fairer comparison would be obtained by considering the cyclist followed by a car with 1 bike on the roof as the reference situation instead of the cyclist riding alone, because indeed there is always a car with at least 1 bike on the roof riding behind the time trial cyclist, as shown in Fig. 2. Table 9, Table 10 hold the corresponding values. We again only discuss the results for the top time trial speed of 50.4 km/h, because these yield the smallest time gains. For a car with 10 bikes, as in Fig. 2a, the additional drag reductions compared to a car with only 1 bike are 0.32, 0.14 and 0.09% for d = 5, 10 and 25 m, respectively. This provides additional time gains per kilometre of 0.07, 0.05 and 0.04 s. For the car with the 2 bikes placed perpendicularly, the additional drag reductions are 2.99, 0.89, 0.50 and 0.36% for d = 1, 5, 10, 25 m, respectively. The corresponding additional time gains per km are 0.77, 0.21, 0.12 and 0.08 s. Finally, for the car with the vertical plate, the additional drag reductions are 4.15, 1.89, 0.99 and 0.65%, and the additional time gains 1.09, 0.44, 0.23 and 0.15 s for d = 1, 5, 10, 25 m, respectively.

1-s2.0-S0167610524000862-gr7.jpg

When you are thinking about putting additional bicycles on the roof of the following team car, you officially run out of ideas.

This is why I dislike competitions where we try to evaluate "the best" among people with tenths of a second differences. I'm sure there are better ways to spend our time, energy and resources.
 
  • #5,986
jack action said:
This is why I dislike competitions where we try to evaluate "the best" among people with tenths of a second differences. I'm sure there are better ways to spend our time, energy and resources.
But it's harmless. In this day and age I see this as a major advantage.
 
  • #5,988
TIL that on March 11, 1978, Claude François died of an electric shock in his Paris apartment when he touched a broken lamp from the bathtub. He was the one who wrote (with Jacques Revaux and Gilles Thibault, the version you know is a cover, translated by Canadian musician Paul Anka) Comme d'Habitude! What a stupid death at 39!
 
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  • #5,989
TIL that tree trunk can contain more than a trillion microbes (bacteria and archea, fungi not counted).
Science news article.
biorxiv.

Interesting info bit: trees are estimated to have 450 gigatons of carbon, animals only have about 2 gigatons of carbon.
 
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  • #5,990
 
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  • #5,992
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  • #5,993
fresh_42 said:
TIL about FC United Manchester on a TV documentation and a very special dialect.
Most Man U fans I know supported it. Deep down though? The club is a business and the major share holders sold their stock legally.
The protesters seem to be quieter when we are winning!
Good luck to FC though.
United had the green and gold away kit in 93 worn by Eric Cantona one of my heros.
Beckham took a green and gold scarf off a fan on his return to OT when he was with Madrid.
Stir things up a little!
 
  • #5,994
pinball1970 said:
Most Man U fans I know supported it. Deep down though? The club is a business and the major share holders sold their stock legally.
The protesters seem to be quieter when we are winning!
Good luck to FC though.
United had the green and gold away kit in 93 worn by Eric Cantona one of my heros.
Beckham took a green and gold scarf off a fan on his return to OT when he was with Madrid.
Stir things up a little!
I liked that one fan was wearing a knit cap with FC St. Pauli printed on it. It is one of our rebel clubs.
 
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  • #5,995
TIL: how my surveyors laser level can still be used, even though I had given up on it.

1000004191.jpg

It is way too dim to see the beam play across any surface more than 6 feet away during the day, even with the JooJanta 200 goggles that come with it.

But I just had the brilliant inspiration to get a small shiny surface and stick it in the way. The first thing at-hand was a metal pencil case.

The beam can easily be seen ay any point along the entire length of my yard. Had to take a video to capture it, but there it is:
1000004211.jpg


I did some experimentation to see how accurate a level line I could get with the bubble levels.

A mere quarter turn of the adjustment knob offsets the beam by 1/2 inch over 20 feet, and I can easily distinguish a tilt of much less than a quarter turn with the bubble levels. So I think I can get within 1/8 inch over 20 feet.
 
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  • #5,996
DaveC426913 said:
even with the JooJanta 200 goggles that come with it.
...because the beam is still powerful enough to be perilous? Or because it is no longer powerful enough to be perilous?
 
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  • #5,997
Screenshot 2024-07-28 at 8.35.08 AM.png
 
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  • #5,998
TIL that 1 in 12 men are colorblind.
:frown:
 
  • #5,999
  • #6,000
TIL that and how you can measure c with a microwave and a slice of cheese.
 
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