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Is the world really running out of sand?

practical.engineering

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Re: Is the world really running out of sand?

#171

Post by kilna »

dyauspitr wrote: post #154

I didn’t exactly understand the take away from this video. In the first test he does, the river sand concrete is three times stronger than the desert sand concrete, but in the second test, the desert sand concrete is 10% stronger than the river sand concrete. What exactly is going on?

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.

Re: Is the world really running out of sand?

#172

Post by Ekaros »

oe wrote: post #157
eru wrote: post #149

Earlier quoted context omitted.

> 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.

My favorite example of this is trucks transporting Finnish bottled water to France and then bringing French bottled water back.

Reminds me of getting can of S.Pellegrino water with something in it. Looked at back of the can and wondered why is this in Japanese... So my guess is that it was first made in Italy, then shipped to Japan and then imported back to Finland...

One starts to question sanity of our consumption habits at times. I am no way environmentalist, but this sort of stuff just seems waste of energy inputs.

Re: Is the world really running out of sand?

#174

Post by alickz »

jzb wrote: post #18
crmrc114 wrote: post #2

Bonus points for articles that start with a tldr and don't try to bury the lead

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…

is graf short for paragraph? i haven't seen that before

Re: Is the world really running out of sand?

#175

Post by eru »

Ekaros wrote: post #172
oe wrote: post #157

Earlier quoted context omitted.

My favorite example of this is trucks transporting Finnish bottled water to France and then bringing French bottled water back.

Reminds me of getting can of S.Pellegrino water with something in it. Looked at back of the can and wondered why is this in Japanese... So my guess is that it was first made in Italy, then shipped to Japan and then imported back to Finland... One starts to question sanity of our consumption habits at times. I am no way environmentalist, but this sort of stuff just seems waste of energy inputs.

As long as you can ship stuff on a boat over the ocean, and don't care too much how long it takes, shipping it even multiple times across the planet is fine. Barely costs anything, both in terms of money and in terms of resources.

The (first and) last miles via truck can cost a lot more, but you can't guess those from whether there's Japanese writing on the label.

Re: Is the world really running out of sand?

#176

Post by jagrsw »

niklasbuschmann wrote: post #114
cdchn wrote: post #104

Earlier quoted context omitted.

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

I assume there are taxes and transmission fees on top of the spot electricity price

Yup, in one of eu countries i have it on my bill: it's ~0.10EUR/kWh electricity and additional ~0.15-0.20EUR/kWh for taxes + transmission + maintenance, IIRC

Re: Is the world really running out of sand?

#177

Post by iamacyborg »

larsrc wrote: post #81

We fools here in Germany sometimes _pay_ to get rid of excess electricity when it's very sunny and windy. How about having some rock crushing machines that instead use that cheap electricity to make more sand? Thanks for the puns, too.

Time to setup some gravitational batteries to exploit that opportunity.

Re: Is the world really running out of sand?

#178

Post by krisoft »

gorfian_robot wrote: post #129

there are lots of types of sand for specific purposes just like say different kinds of wood. unfortunately while we can essentially 'farm' certain kinds of wood that really isn't possible for sand.

> 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.

Re: Is the world really running out of sand?

#179

Post by pfdietz »

lazide wrote: post #151
pfdietz wrote: post #142

Earlier quoted context omitted.

There is nothing special about petrochemical energy when it comes to growing food. We could run the agricultural system on other energy sources. In the US, the total fraction of energy used for agriculture is about 1%. We use more energy cooking food than growing it.

Hydrocarbons contain massive quantities of easily liberated energy and large quantities of easily liberated hydrogen. Which are then easily and economically converted to ammonia to power the largest single form of fertilizer used in the world - nitrogen fertilizer, in the form of ammonium nitrate and equivalents. [ https://en.m.wikipedia.org/wiki/Haber_process ] 10’s of millions of tons/year are produced right now. T…

It's harder, but if one looks at the externalities from fossil fuel consumption, it's actually cheaper to use renewable energy now.

Hydrogen for ammonia production is very cheaply storable (underground, like natural gas is stored) and would provide a large dispatchable demand to ease integration of renewables into the economy, smoothing over long timescale intermittency.

In any case, because the energy used for agriculture is so relatively small, if the economy as a whole can get off fossil fuels, agriculture certainly can as well.

Re: Is the world really running out of sand?

#180

Post by lazide »

pfdietz wrote: post #179
lazide wrote: post #151

Earlier quoted context omitted.

Hydrocarbons contain massive quantities of easily liberated energy and large quantities of easily liberated hydrogen. Which are then easily and economically converted to ammonia to power the largest single form of fertilizer used in the world - nitrogen fertilizer, in the form of ammonium nitrate and equivalents. [ https://en.m.wikipedia.org/wiki/Haber_process ] 10’s of millions of tons/year are produced right now. T…

It's harder, but if one looks at the externalities from fossil fuel consumption, it's actually cheaper to use renewable energy now. Hydrogen for ammonia production is very cheaply storable (underground, like natural gas is stored) and would provide a large dispatchable demand to ease integration of renewables into the economy, smoothing over long timescale intermittency. In any case, because the energy used for agric…

Since neither the general economy nor agriculture has gotten anywhere near getting off fossil fuels yet, that is assuming a lot isn’t it?

Even if electrical grid needs are 100% renewable, that is just a couple percent of most economies energy usage.

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