How are moderators allowed to lie?

[tooki]

https://en.wikipedia.org/wiki/Millennium_Bridge,_London#:~:text=The%20bridge%20opened%20on%2010,on%2012%20June%20for%20modifications.

"Unexpected lateral vibration due to resonant structural response caused the bridge to be closed on 12 June for modifications."

A bridge and a building are not the same thing.

[SteveThackery]

"Unexpected lateral vibration due to resonant structural response caused the bridge to be closed on 12 June for modifications."

Goodness me, you are hard work! Firstly, it was a bridge, not a building. Secondly, it was in no danger of being demolished - it just upset the people on it. That is very important.

Find me an example of a vibratory device capable of demolishing an actual building and we might take it more seriously. The only one I can think of is the earth itself, when it's having an earthquake. The energy input is so vast, resonance and damping are both irrelevant.

Anyway, I should stop, otherwise we'll just end up extending the thread that got locked.  You should apologise for accusing the moderator of lying. He expressed his opinion - that is not lying.

Tell me: are you one of those people who see conspiracies everywhere, and believe that "free energy" is being suppressed by the dark forces of capitalism and vested interests?

[IanB]

Find me an example of a vibratory device capable of demolishing an actual building and we might take it more seriously.

To be fair, engineers have to take the wind very seriously when designing tall buildings. The main reason skyscrapers don't get damaged in high winds is that engineers know their jobs and design them carefully to avoid problems like resonance. Also, the wind delivers a power level far in excess of anything a human device could apply to the building.

[SteveThackery]

You referenced the wrong thing. Try this instead:

Tesla made no claims about bridges, as far as I've read. He specifically claimed he could demolish a building with a device he could hold in his hand.  In the last days of his life he claimed he had such a device in storage. When the box was opened up after he had died, it contained.... dammit, I can't remember, but it was just a normal piece of lab equipment - a voltmeter, or something like that.

The energy input to that bridge was somewhat beyond anything a hand-sized device could deliver!

[tooki]

Find me an example of a vibratory device capable of demolishing an actual building and we might take it more seriously. The only one I can think of is the earth itself, when it's having an earthquake. The energy input is so vast, resonance and damping are both irrelevant.

I do know that many really big skyscrapers use tuned-mass dampers to prevent wind from causing resonant oscillations that could lead to “unscheduled disassembly” of the structure. So the principle of buildings being excited to a damaging resonant frequency is real, and seemingly understood by engineers.

[SteveThackery]

To be fair, engineers have to take the wind very seriously when designing tall buildings. The main reason skyscrapers don't get damaged in high winds is that engineers know their jobs and design them carefully to avoid problems like resonance. Also, the wind delivers a power level far in excess of anything a human device could apply to the building.

Yep, I wouldn't dispute any of that. As far as I know, it's steel-framed buildings that will vibrate at a resonant frequency, and such buildings employ internal dampers to reduce the vibration. As you say, we are a very long way from demolishing a building with a hand-sized device.

I mentioned it in the first place to illustrate my claim that Tesla seemed to have to conception of damping and energy losses in a system. It is a strange blind spot to have.

[themadhippy]

He specifically claimed he could demolish a building with a device he could hold in his hand.

Hammer and chisel?

[IanB]

Tesla made no claims about bridges, as far as I've read. He specifically claimed he could demolish a building with a device he could hold in his hand.  In the last days of his life he claimed he had such a device in storage. When the box was opened up after he had died, it contained.... dammit, I can't remember, but it was just a normal piece of lab equipment - a voltmeter, or something like that.

The energy input to that bridge was somewhat beyond anything a hand-sized device could deliver!

I know. I was just pointing out there was a much better example to pick when illustrating the dangers of resonance in man-made structures.

[SteveThackery]

So the principle of buildings being excited to a damaging resonant frequency is real, and seemingly understood by engineers.

Of course it is and I haven't disputed that. Such resonance requires an energy input way beyond anything a little device the size of a kilogram packet of sugar could deliver.  That's because of the losses involved; I mentioned it to illustrate that he didn't seem to understand losses and damping.

[SteveThackery]

I know. I was just pointing out there was a much better example to pick when illustrating the dangers of resonance in man-made structures.

Totally - and we are in agreement.

[IanB]

He specifically claimed he could demolish a building with a device he could hold in his hand.

Hammer and chisel?

Well, Fred Dibnah demolished large industrial chimneys with a hammer and chisel, so it is not impossible. (Sometimes the surrounding infrastructure did not allow a chimney to be demolished by dynamite or making it fall over. So it had to be taken down brick by brick.)

[tszaboo]

I don’t think that’s a reasonable representation of the history.

Nor is what others are describing in this thread or any discussion where Edison and Tesla come up in.
The point is that probably ancient Greeks had some sort of rotating magnets with their battery.
Meanwhile these guys were the fist creators of electric railways and transformers that you could actually order.
And Edison also had a company that still makes... Airplane turbines apparently.

[SteveThackery]

MODERATORS

Although I'm enjoying this, we are at risk of running another thread about the miracles and magic Tesla could do (according to his 21st century fan club), which I'm not sure is appropriate for EEVblog.

I'm mindful of this and feel I should stop here. There are plenty of other forums more suitable for this nonsense.

PS: the OP still needs to apologise for accusing the moderator of lying. That was a pretty bad slur.

[tooki]

So the principle of buildings being excited to a damaging resonant frequency is real, and seemingly understood by engineers.

Of course it is and I haven't disputed that. Such resonance requires an energy input way beyond anything a little device the size of a kilogram packet of sugar could deliver.  That's because of the losses involved; I mentioned it to illustrate that he didn't seem to understand losses and damping.

I wasn’t saying anything about palm-size devices. You said you couldn’t think of any energy source other than earthquakes, and I pointed out that wind is a real-world source of destruction-level resonances (or would be, if we didn’t mitigate that effect).

[Simon]

So they can have opinions and shut down and lock a thread based on their opinions?

If Tesla died broke, doesn't that point to him not having the influence to be able to claim an invention over all others?

He has a SI Unit named after him but he's a fraud. So then EVERYONE is a fraud.

Did you look at the video? no of course not. Instead of your rage how about some formulated opinion?

Tesla was a charlatan, end of. anyone invoking his name like a god is an even bigger chalatan, at least tesla had the fucking balls to be original. Now quit winging about reality or get the fuck out!

[IanB]

And before the thread gets locked, there is of course a problem with the word "invention" as used, for example, with patents.

To a sufficiently advanced mind, one familiar with all the physical laws of the world, every conceivable device is "obvious". Any such device is simply a solution to a problem, and when faced with such a problem, it is pretty obvious how to make something that solves it. Therefore, if there are many people simultaneously encountering a given need or problem, they will all be likely to solve it in a similar way.

The whole legal theory of patents is that most people are not very intelligent, and so when a "smart" person devises a gadget that does something useful, it looks to everyone else like a miracle, and worthy of special regard.

Today, patent law operates like the system of mining claims. Whoever first sticks a stake in the ground and makes a claim, their claim is given legal protection. Which leads to the ludicrous situation today where patent filers make claims about anything and everything, just so they can prevent other people claiming the same thing.

[tooki]

Tesla was a charlatan, end of.

Well I don’t think that’s a reasonable interpretation, and certainly nothing you can say “end of” to, since that’s an opinion, not a fact.

As I said above:

On the video [Simon] posted, I made this YouTube comment 2 years ago, which I think is a more balanced take on the matter:

This video mirrors what I have told people for years. What’s weird about Tesla is that it’s just this century that the history about him went all wacky. As someone who was aware of Tesla and his accomplishments long before that, it was really weird to see him go from “guy who invented a practical AC motor” known by nerds only, to “techno wizard visionary” revered by quacks and laypersons.

And as SteveThackery beautifully worded above:

We honour him most by acknowledging the inventions he proved to work; it dishonours him to fabricate an entire fantasy world of heroes and villains, where magic rules over physics and the forces of evil oppress our hero and us little people.

Did you look at the video? no of course not. Instead of your rage how about some formulated opinion?

Tesla was a charlatan, end of. anyone invoking his name like a god is an even bigger chalatan, at least tesla had the fucking balls to be original. Now quit winging about reality or get the fuck out!

I will also add that, as a moderator, we kind of expect a bit more professionalism than this post exhibits. I can understand your frustration, but as a moderator, this tone looks bad.

[DejanC]

Tesla was a charlatan, end of.

Well I don’t think that’s a reasonable interpretation, and certainly nothing you can say “end of” to, since that’s an opinion, not a fact.

Exactly!

If he was a charlatan, why did we name an SI-unit after him? Why was he allowed to give lectures to other electrical engineers? If he was a charlatan, how did he have so many inventions we still use today: radio, x-rays, induction motor, tesla transformer?

[pcprogrammer]

He specifically claimed he could demolish a building with a device he could hold in his hand.

Hammer and chisel?

 

Very funny but that has nothing to do with resonance and instant collapse after excitation. Just taking a long time (depending on the size of the building) to chip away at the base of the building before it tips over.

With resonance a structure reaches a point where the amplitude of the vibration surpasses what the structure can withstand. Similar to electronics, were a resonant circuit can become over excited and destroys itself.

[IanB]

If he was a charlatan, why did we name an SI-unit after him? Why was he allowed to give lectures to other electrical engineers? If he was a charlatan, how did he have so many inventions we still use today: radio, x-rays, induction motor, tesla transformer?

I explained that above in my post about patents. At the time, in the late 19th century, when there was burgeoning interest in the industrial applications of electricity, many people were going to discover (discover, not invent) those things, and many people did. They would have been independently discovered at different times by scientists, engineers and entrepreneurs exploring the fascinating new world of electricity.

[DejanC]

I explained that above in my post about patents. At the time, in the late 19th century, when there was burgeoning interest in the industrial applications of electricity, many people were going to discover (discover, not invent) those things, and many people did. They would have been independently discovered at different times by scientists, engineers and entrepreneurs exploring the fascinating new world of electricity.

Ok so independently discovering these things makes him a charlatan really? That's the claim.

[IanB]

Very funny but that has nothing to do with resonance and instant collapse after excitation. Just taking a long time (depending on the size of the building) to chip away at the base of the building before it tips over.

Sometimes you have to start at the top and work down, brick by brick, so it doesn't fall over:

[DejanC]

Take a look around the 47 minute mark...

[pcprogrammer]

Tesla was a charlatan, end of.

Well I don’t think that’s a reasonable interpretation, and certainly nothing you can say “end of” to, since that’s an opinion, not a fact.

Exactly!

If he was a charlatan, why did we name an SI-unit after him? Why was he allowed to give lectures to other electrical engineers? If he was a charlatan, how did he have so many inventions we still use today: radio, x-rays, induction motor, tesla transformer?

You are just running around in the same circle until we all agree that you are right. Sorry but I don't see that happening. It is in your perception that he was a great inventor, and in the perception of others he was just a smart guy who came up with very interesting things, but also was a bit weird.

You mention radio but forget that Guglielmo Marconi is cited as being the inventor of the radio. Wilhelm Roentgen is cited as the person who discovered x-rays. Need I go on.

As written by others in this thread a lot of "inventions" were made at more or less the same time by different people across the world. Many so called modern inventions were already known of in ancient times. Think of the Chinese, the Romans, the Greeks, the Moors, etc.

For instance concrete has been seen used in Roman structures, but the methodology was forgotten about for many centuries to only be rediscovered as a very strong building material.

See my first response to your original post and think about that.

[SteveThackery]

You said you couldn’t think of any energy source other than earthquakes, and I pointed out that wind is a real-world source of destruction-level resonances (or would be, if we didn’t mitigate that effect).

Ah, OK - thanks.