Just marveling as an old school computer programming geek that I happen to be in a forum that also includes someone in the tugboat business.

Indeed!

Then there is all kinds of specialty sands - say, when replacing the sand in our local athletics union long jump pits, I learned that one should use sand from river beds (as opposed to sand crushed at a plant) as the river sand is much less likely to cause abrasions, seeing as all the sharp edges have been worn away as the sand has been shifted back and forth by the river current...

Sand is not just sand.

> A country can be both an exporter and importer of sand.

That's pretty normal in general. Eg Germany both imports and exports a lot of cars.

Trade is a technology that turns concrete sand into aquarium sand.

While not sand, I remember reading about the state of Colorado importing specialty dirt from around the world while constructing I-70 through the Rockies. Various properties were required that couldn’t be found from local dirt.

Yeah but there is going to be a massive imbalance in the quantity of those two types of sand. I bet the sand required for aquariums is a rounding error on the amount of sand required for concrete.

The problem is that what defines a “citable source” for Wikipedia is loose at best and malicious at worst. There are many examples where “improper” sources are accepted, especially in social matters, because they benefit a certain viewpoint. STEM is, for the most part, decent, but anything covering the life of people needs to be considered carefully due to the lack of several types of important sources and the biases present on many people’s pages.

The BBC Maths and Statistics programme 'More or Less' has coined a term for statistics like this - 'Zombie Statistics'. An initial, often misquoted fact, which is useful as a soundbite and gets repeated over and over and over again, despite multiple debunkings.

100% - he calmly explains various approaches and their tradeoffs.

He’s not exactly a traditional journalist, but this is what I want the future of journalism to be like. People with subject matter expertise explaining their thing simply and clearly.

>It gives me hope that teenagers are watching his videos and becoming inspired to go into infrastructure.

Sadly, that was me ~10 years ago, but the lure of FAANG money was too strong and I went into EE/CS after 1 year as a civil engineering major. I wonder if one day we will really start feeling the affects of this talent reallocation, and civil engineering will become a higher paying profession.

Essential node in global semiconductor supply chain hit by Hurricane Helene | 196 points | 50 comments | https://news.ycombinator.com/item?id=41701862

> and 70% of the world's supply comes from just one place in North Carolina

A quick search seems to say there are more places available for getting that than North Carolina.

Is it possible that this specific mine just happens to be the cheapest available right now, but in case they for some reason disappear, there are alternatives everyone would switch to? Or is the situation that if that mine disappears, there is no other alternatives at all?

Oh, cool. One of the most common glass batches (raw materials melted to make glass) used by artists is "Spruce Pine Batch".

Spruce Pine doesn't use sand, they mine large quartz crystals out of pegmatites.

I wrote this comment on an article that was on HN about 6 months ago: https://news.ycombinator.com/item?id=39818778

Sadly, given the insane amount of devastation in western NC, I'll get a chance to test my hypothesis. That is, despite Spruce Pine going offline, the overall impact to the global semiconductor industry will be relatively unnoticeable.

I'm not sure that's technically irony but rather an interesting coincidence.

A coincidence is not ironic

The majority of the earth's crust is believed to be made of silicon dioxide. I don't know how much I would believe that we would have a scarcity. It may all come from one source simply because of history.

One of the proposals for exploiting zero (or negative) electricity prices is storage of the heat at high temperature in refractory solids. This would be used by people who normally burn a fuel for the heat. Instead, they can preheat air and reduce the fuel needed (perhaps reduced to zero).

Firebrick works up to about 1000 C. A spinoff from MIT is using special nickel-doped chromium oxide (chromia) bricks, which can work up to 1800 C, about the temperature of a natural gas-air flame. These bricks are electrically conductive and can act as their own heating elements.

https://www.fastcompany.com/91129126/these-bricks-conduct-el...

https://electrifiedthermal.com/

https://dspace.mit.edu/handle/1721.1/130800

It's quite likely that the cost of idle capital is much higher than the cost of paying others to accept electricity. Depending on the price swings, a battery may be a much better investment.

I hate to say this, but why aren't the Bitcoin miners jumping all over that?

Free power doesn’t mean free production.

There’s also labor, wear on the machines and the lost opportunity of using your money to do something else. Building such crushing machines and only use them x% of the time (for, for now, fairly small values of x) may not be a good investment.

Time to setup some gravitational batteries to exploit that opportunity.

Another book on this is:

_Material World: The Six Raw Materials That Shape Modern Civilization_ by Ed Conway

https://www.goodreads.com/book/show/112974899-material-world

>Sand, salt, iron, copper, oil, and lithium. These fundamental materials have created empires, razed civilizations, and fed our ingenuity and greed for thousands of years. Without them, our modern world would not exist, and the battle to control them will determine our future

What about eg air, wood? Used by mass or volume or?

Agreed, I read it earlier in the year and found it enlightening.

I almost feel like his videos are anti-clickbait. On my YouTube recommendations page, often his title and cover image are the least eye-grabbing, but the actual video is always satisfying.

I don't even care about sand but he's so great I couldn't stop watching it

> Add me to the long list of people who heard the bit about desert sand not being suitable for concrete and believed it. I'm happy to be corrected.

Cristobol and Hank's whole business strategy down the drain! (From Barry)

He's got a great book as well. I got it because my 4 yo is a Grady fan but I enjoy it and learn a lot as well. "Engineering in Plain Sight: An Illustrated Field Guide to the Constructed Environment"

I loved how he tackled this from multiple angles.

Manufactured sand has those rough edges, and is often a waste byproduct of rock crushing anyway. But also, in practice, you want more weathered sand for ease of handling, since too-rough sand is less strong given the same level of workability!

I love his book too. I ended up buying a copy for my sister who kept asking me how I knew all their weird details about things like sewer systems :-)

> Gets right to the point in the first sentence,

Huge respect or the "tldr: no" right at the start.

Exploding means it was keeping its integrity for longer (i.e. not compressing), and then releasing it when it couldn't anywhere.

Crumbling means it was falling apart.

A paper book will explode in a press because it does not have any way to compress and release any of the force on it, until it releases all of it in one shot.

Putting stress on the concrete requires force, and causes the concrete to deflect. Force over displacement is work, and energy can't be lost to nothingness by just breaking the concrete. Thus, the concrete releases the stored up energy as kinetic energy of its fragments.

Stronger concrete requires more stress to cause it to fail, and as such it takes more force to break it. There is logically more energy because of the higher force, so more energy gets released.

Nebula is fantastic

Yeah, I subscribe to Nebula -- and he's actually the reason I did. They have a decent size catalog although my interests are narrow enough that I only actually follow a couple of channels there. But that's certainly been worth the price.

It's normalising for different things.

If you normalise for the the same ratio of cement / water / gravel / sand then sharp-sand (crushed rocks) is stronger.

If you normalise for workability (i.e. the concrete flows and can be worked easily) you need to add additional water to sharp-sand, which means that the smooth-sand (e.g. river-rocks) end up stronger.

He explained it in the video. The amount of water was adjusted so the viscosity (well, workability) was identical between the samples in the second test. Less water in concrete has a huge positive influence on strength, and rough sand needs more water to be workable. Thus, for comparably workable samples, rounded sand concrete with less water was actually stronger.

The US has had a long way to fall. In a wealthy economy can suffer a great deal of public finance abuse: there are many wells that need to be dried up. The progression of the US toward that goal includes, most recently: progressively shifting to ever shorter term notes to finance deficits and large scale monetizing of deficits, such as during the Great Recession and COVID.

We'll get there. You'll know it's over when you get "bailed in" and the treasury starting minting trillion dollar coins.

Public debt is more like a brake that gets worse and worse really slowly over time.

And then it suddenly explodes - more and more of the budget goes to interest payments instead of procurement.

At one point the government has to borrow to make payments on the debt, and then you’ve got a very bad spiral.

Note that "bury the lede" isn't really about "make the reader get to the end to find out the answer" but when a reporter/writer emphasizes the wrong part of a story in the intro then you'd say they buried the lede. Like, if the first graf is all about a politician attending a ribbon-cutting ceremony in Podunk, IL and then in the third graf you have "at the rally, he called for all left-handed people to be put in jail" then you've buried the lede.

If you have in the first graf "so-and-so proposed a radical, and illegal, prosecution of a minority group" it's not burying the lede to make the reader get to the third graf to find out it's against left-handed people. Annoying, perhaps, but not technically burying the lede. :)

The Washington Post headline:

>'The Eagle Has Landed' – Two Men Walk on the Moon

That is the entire story, in the headline as it should be. I want to know more! The first sentence should add the most relevant added information.

It shouldn't be "As a child Neil Armstrong always dreamed about..." burying the next most important detail 2/3 through the article. The importance/relevance/interest should start high, end low. Inverted pyramid.

FYI it's "bury the lede," a lede being the introductory section of a news story.

Funny thing is that crushing rocks could be solution to CO2. Olivine rock chemically fabsorbs CO2 when dumped in seawater. Crushing the rock increases the surface area.

Mining, crushing, and dumping rock are all something that we can do, and should be doable when electricity is cheap and green. It should be more efficient than pulling CO2 out of the air.

The sand is first screened to separate out larger objects, then washed to eliminate clay/silt/fine particles. Then it goes through a couple more steps to separate out quartz, magnetic minerals, etc before finally batches are tested for silicon dioxide content and impurities using xray fluoroscopy and other spectroscopy methods. The purer a batch is, the higher end the customer.

Most localities can’t produce sand good enough for semiconductors or optics because they contain impurities that are too hard to remove so most of it is used for concrete or glass.

> unfortunately while we can essentially 'farm' certain kinds of wood that really isn't possible for sand.

The linked article demonstrates this to be false.

It turns we’re all in the pocket of big sand. Which I guess is better than having big sand in our pockets, as that would scratch up our phones. Then, we’d need new phones, or at least new phone screens… either way, big sand wins!

That would probably cause the sand to become smoother.

> I wondered why we didn't just blast desert sand at itself to rough it up to give it better properties.

The grain size of desert (or most maritime) sand is already far too small, and if you blast it to pieces it will get even smaller - too small to be used for concrete.

If you think sand usage is primarily silicon power electronics you're missing a lot.

Isaac Asimov was an early writer on this, noting that if the earth's crust was converted into biomass the limiting element was phosphorous --- look at USDA photos of food crops grown w/ and w/o fertilizer including that element for a very sobering view.

Currently, we expend up to 10 calories of petro-chemical energy to get 1 calorie of food energy (depending on food) --- peak oil is still worrisome given how much of the input for fertilizers is from oil.

Sometime in the last century we crossed over from their being more weight in bony fish in the oceans than shipping tonnage to the latter predominating: https://what-if.xkcd.com/33/

My grandfather lived in a time when commercial hunting was outlawed --- I worry my children will live in a time when commercial fishing is no longer feasible.

If you add a single grain of sand to a tonne of snow, it’s not 85% sand.

I don’t understand how you got that conclusion — 1 grain of sand is not 85% of the [ton of snow + 1 grain sand]

How does that one grain become 85% of a tonne?

You didn’t watch the video.

Did you watch the entire video? I ask because Grady discusses EXACTLY this point.

He explains that the whole 'more expensive' thing is really just noting the actual cost of sand versus ignoring the externalized costs of mining it. When you dig up a river bed there is a cost there that isn't necessarily reflected in the cost of the sand you mined from there, sometimes because that cost is passed on to someone else who has to remediate the site after you mined it (like taxpayers). He empirically points out that different sands need a different water/cement ratio and also points out that the papers on sand use in concrete understand that. The 'bug' seems to be that people just add 'x' water to the mix and if the sand changes they might get different results.

Haven't read the article, but I watched the video. He goes on to say that it's not the full story, and he also does some tests where instead of optimizing for a particular water ratio in the mix, he optimizes for a specific texture when mixed, which is termed "workability". If you keep "workability" constant, you can put much less water in the mix, resulting in a stronger concrete when cured.