Arecibo Collapsed Because of Engineering Failures That Inspectors Failed To Spot (behindtheblack.com) 38
An anonymous reader quotes a report from Behind the Black: According to a new very detailed engineering analysis into the causes of the collapse of the Arecibo radio telescope in Puerto Rico in 2020, the failure was caused first by a surprising interaction between the radio electronics of Arecibo and the traditional methods used to anchor the cables, and second by a failure of inspections to spot the problem as it became obvious.
The surprising engineering discovery is illustrated [here (PNG)]. The main antenna of Arecibo was suspended above the bowl below by three main cables. The figure shows the basic design of the system used to anchor the cable ends to their sockets. The end of the cable bunches would be inserted into the socket, spread apart, and then zinc would be poured in to fill the gap and then act as a plug and glue to hold the cables in place. According to the report, this system has been used for decades in many applications very successfully.
What the report found however was at Arecibo over time the cable bunch and zinc plug slowly began to pull out of the socket, what the report labels as "zinc creep." This was noted by inspectors, but dismissed as a concern because they still believed the engineering margins were still high enough to prevent failure at this point. In fact, this is exactly where the structure failed in 2020, with the first cable separating as shown in August 2020. The second cable did so in a similar manner in November 2020.
The report concluded that the "only hypothesis the committee could develop that provides a plausible but unprovable answer to all these questions and the observed socket failure pattern is that the socket zinc creep was unexpectedly accelerated in the Arecibo Telescope's uniquely powerful electromagnetic radiation environment. The Arecibo Telescope cables were suspended across the beam of 'the most powerful radio transmitter on Earth.'"
The surprising engineering discovery is illustrated [here (PNG)]. The main antenna of Arecibo was suspended above the bowl below by three main cables. The figure shows the basic design of the system used to anchor the cable ends to their sockets. The end of the cable bunches would be inserted into the socket, spread apart, and then zinc would be poured in to fill the gap and then act as a plug and glue to hold the cables in place. According to the report, this system has been used for decades in many applications very successfully.
What the report found however was at Arecibo over time the cable bunch and zinc plug slowly began to pull out of the socket, what the report labels as "zinc creep." This was noted by inspectors, but dismissed as a concern because they still believed the engineering margins were still high enough to prevent failure at this point. In fact, this is exactly where the structure failed in 2020, with the first cable separating as shown in August 2020. The second cable did so in a similar manner in November 2020.
The report concluded that the "only hypothesis the committee could develop that provides a plausible but unprovable answer to all these questions and the observed socket failure pattern is that the socket zinc creep was unexpectedly accelerated in the Arecibo Telescope's uniquely powerful electromagnetic radiation environment. The Arecibo Telescope cables were suspended across the beam of 'the most powerful radio transmitter on Earth.'"
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A solution should be engineered that accounts and corrects for these inadequacies with the zinc connection point, and the equipment should be rebuilt and re-established with better, lighter weight electronics that our modern solutions can facilitate. It would not take that much, in the grand scheme of things to repair / replace it. Probably less than 1% of what we have given to Ukraine thus far this year.
The money and stuff we gave to Ukraine is only partially wasted. Most of it isn't really spent; it's moved around. The US legislature approves the expenditure. The US government distributes the money while incurring a debt. The oligarchs in Europe take a slice. The legislators themselves get some too. Contractors make some money. various people who set things up get a commission. Some of the money actually goes to the over-priced weapon systems and shipping them.
When the government spends money it is not th
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There are other factors as well. In the past the US has literally paid other countries to dismantle and destroy various kinds of weapons in their arsenals. Additionally the US has destroyed their own weapons in parity with other countries (like the USSR), with inspectors from both countries verifying that both countries did indeed follow through with the agreements. Both are forms of global disarmament that, unfortunately, costs (in money and / or lives).
This is really no different - every dollar spent in U
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Much more likely that the banding together of NK, Russia, now Iran and China will be marked as the end point of US hegemony.
Re: Since the problem has been identified (Score:1)
What do you mean a PP tries to minimise expense. A PP tries to maximise what it charges its customer (us).
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Okay, let's let facts intrude on things.
In the first two years, there was a total of approximately $380B of global aid [cnn.com] "committed" to Ukraine, although "commitments" are often vastly more ambitious than actual reality [ifw-kiel.de]. In the ballpark of $190B/yr. Europe provides the majority of this. However, this is a mixture of military aid, humanitarian assistance, financial support, and a variety of other factors (more on this in a bit). Historically the US was the main military contributor, with the EU more focuse [atradius.com]
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To add a bit more context: the US military budget - eg. the organization whose entire purpose for existence is to be able to resist major US adversaries (one of which is Russia, which is being disarmed in Ukraine) has a budget this year alone of $841B, or $2432 per American.
And re: "disarming": Russia started the war with the world's largest stockpiles of many equpiment types - their inheritance of over half a century of Soviet production, equipment the Soviet Union had stocked up to be able to zerg rush th
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Oh, and forgot to add, re, economics: Russia's inflation is so out of control that the central bank has set its interest rate to 21% to try to slow it [cnbc.com] (US fed rate: 5%). Russia's short-term bond yields are now similar to Uganda's [tradingeconomics.com], and continuously worsening. Meanwhile, in the intense labour shortage, reduced maintenance has been slowly hollowing out an already often fragile infrastructure system.
Basically, the country is funding its war by mortgaging its past (Soviet equipment inheritance), its present, an
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"Probably less than 1% of what we have given to Ukraine thus far this year."
This is a quote from the paper? Why on Earth would you do this? Whatever your politics, referencing a politically polarized subject in your paper about radio astronomy all but ensures that the subsequent discussion is going to be about the political thing, not the radio astronomy. Just look at the first twenty comments on this Slashdot article! Even if you were attempting to exploit the emotionality of politics to make your dry
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No they don't.
The legislators themselves get some too.
No they don't.
Contractors make some money.
Of course contractors are making money. They're the ones being paid to make the munitions and equipment. Did you think the government was making this stuff?
Some of the money actually goes to the over-priced weapon systems and shipping them.
If you think they're overpriced the U.S. governmet would love to see you bid on their weapons contra
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Exactly what use do you think a howitzer is going to do for Arecibo?
Re: Since the problem has been identified (Score:1)
I dunno, could be used to fire a projectile with new cables in tow?
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Ukraine funding is small minor compared to what we give Israel.
Re: FTW, Puerto Rico. (Score:1)
Rado telescope is an RF transmitter? I learned something today.
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Source: https://en.wikipedia.org/wiki/... [wikipedia.org]
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"...the most powerful radio transmitter on Earth"? (Score:2)
How? How do these radio waves affect the zinc filler in the socket? What happens?
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It probably heats up the zinc? Maybe?
Re: "...the most powerful radio transmitter on Ear (Score:2)
The two mechanisms I can think of would be that either it heats it up, or it causes things to vibrate and slowly work loose. It would only have to be a tiny effect, it happened over decades after all.
Re:"...the most powerful radio transmitter on Eart (Score:4, Interesting)
Long-term, low-current electroplasticity. The radio waves induced a current in the cables, which ended up grounding through some of the sockets. Or something like that. The report says:
The only hypothesis the committee developed that could possibly explain the measured patterns and ultimate effects of the observed socket zinc creep acceleration was the effect of electroplasticity (EP). EP is "the reduction in flow stress of a material undergoing deformation on passing an electrical pulse through it." EP was first discovered by Eugene S. Machlin, who reported in 1959 that making a 6 kV (dc) closed circuit with NaCl crystals made them weaker and more ductile. Later, in 1963, Troitskii and Likhtman reported the same EP effect in zinc crystals. In 2020, Baumgardner et al. reported the following:
A low-energy electroplastic effect in aluminum alloys at an ultra-low current density threshold between 0.035 and 0.1 A/mm2 that resulted in EP-assisted reduction in hardness of 10% and increases in creep rate up to 38% over a range in temperatures from 25C to 100C. Systematic experiments and ab initio calculations showed that Mg-Zn alloying elements in Al7050 were the origin of the EP effect.
"To date, the theories of Joule-heating, electron-wind force, and de-pinning from paramagnetic obstacles are the most commonly invoked explanations for instances of EP observed in different materials."
You can get the whole report ftom here [nationalacademies.org]
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They attract aliens, which beam down and steal the zinc for their saucers' corrosion protection systems.
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How? How do these radio waves affect the zinc filler in the socket? What happens?
The radio waves would have induced electrical currents in the entire structure. And any mechanical metal-to-metal junctions would have been subject to ingress of water and contaminants. I'm just guessing here, but I suspect that at these points the current flow would be destructive in the same way that an electroplating process sometimes sacrifices one of the electrodes used.
Note that such junctions can become de-facto batteries in any structure where different metals com into contact. The resulting current
Plenty of blame to go around (Score:1)
I'm sure having (ex) OO agents running around conducting firefights on the array back in the 90s didn't help matters either, along with converting it into an easily drained and refilled lake to avoid aerial detection.
Safest way to cut the funding (Score:2)
For a long time there was talk of closing down Arecibo, so letting it collapse is the safest way to stop funding it.
Closing it down would involve saving the most expensive parts, the detectors in the hub suspended above the reflector.
This will also result in the expensive parts being stored for use in a future radio telescope.
The collapse and their destruction solved that problem too.
Trying to follow this (Score:3)
Classism creates corruption which leads directly to incompetence. So long as the upper classes are in control and driven by greed, corruption and incompetence will continue to get worse until society collapses once again.
So society is the dish, greed is the zinc and the RF is the upper classes? Or is corruption the inspectors? And where do the aliens (each according to their needs) fit into this? Sorry, I am lost...
Remember this was in Puerto Rico..... (Score:1)
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A small majority of Puerto Ricans want it to be a state, so there is no overwhelming support for independence. Right now PR is a colony, when we like to pretend colonialism was something that happened in the past. I say we turn Florida into a colony and make PR a state, that way we get an upgrade and don't even have to change the flag.
A World Without Zinc (Score:3)
Come back zinc!! Come baaaaack!!!
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