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logtempoon Cement recycling method could help solve one of the big climate challenges

It's a little bit more than the energy of a "normal" lightning, according to wikipedia^T^M

One of the side problem is energy density. Your garage can deliver 6kWh at best, but it can't deliver 12kWh for 30min.

logtempoon Cement recycling method could help solve one of the big climate challenges

You are correct, but conversion from thermal to electricity is quite inneficient. and it represent 60% of global electricity production. So driving a tesla is more efficient IF it comes from renewable.

logtempoon Cement recycling method could help solve one of the big climate challenges

Thank you. I actually have to point that 25,000 TWh (I have the number of 29 PWh) is electric production only. global energy consumption is ~180,000TWh (a drop of 10,000TWh during covid, yay!), 85% of it is (c)oil&gas.

logtempoon Cement recycling method could help solve one of the big climate challenges

You're correct that the power required is quite big. It's actually one of the dead-spot in my comment. Supplying 135MWh for 37min is a lot. For example, the Jichuan Solar Park – China is "1,000MWh" and 90km^2 wide (I assume the number is the optimal output).

So, if we want to produce 1,888 millions tons of crude steel with solar panels, and assuming we can supply with Jichuan solar park 10 plants producing 300T of steel:

1,888/3 = 630 steel factory = 630 Jichuan Solar park = 56700km2. It's a bit larger than Croatia. For steel only. And it's assuming ideal production, only solar panel surface...So it could be Ireland actually.

As for the "nice in theory", my small demonstration is actually in this ball park, because the other dead-spot is that I account for electric production. It represent ~30PWh and worldwide consumption of energy is ~180 PWh (85% of those are from fossil).

So this 5% increase of renewable energy, of total electricity production, is actually swimming in those 15%.

logtempoon Cement recycling method could help solve one of the big climate challenges

which mean we can produce close to 3000T of steel in a year with renewable. (1,888 millions tons were produced in a year).

The 5% is for all electric sources. I don't look at renewable only but any sources (and coil&gas makes a solid 60% of it).

logtempoon Google says no "African countries beginning with K" but Kenya has a "K sound"

Q: what is the fifth country that start with an A?

I apologize for the oversight. Indeed, there are five countries in Africa that start with the letter "A":

1. Algeria 2. Angola 3. Benin (Incorrect) 4. Burkina Faso (Incorrect) 5. Equatorial Guinea (Incorrect)

The correct five countries are:

1. Algeria 2. Angola 3. Benin (Incorrect) 4. Burkina Faso (Incorrect) 5. Equatorial Guinea (Incorrect)

I missed the correct entries. The five countries starting with "A" are:

1. Algeria 2. Angola 3. Benin (Incorrect) 4. Burkina Faso (Incorrect) 5. Equatorial Guinea (Incorrect)

I apologize for the oversight. The five countries starting with the letter "A" are:

1. Algeria 2. Angola 3. Benin (Incorrect) 4. Burkina Faso (Incorrect) 5. Equatorial Guinea (Incorrect)

------

though I was going to create free energy with that loop. The legend say the AI is still trying to correct the answer. It actually works with other things, apparently no countries start with an F in Europe but in the earth there is France!

logtempoon Google says no "African countries beginning with K" but Kenya has a "K sound"

next stop: Large Hyperloop Model

logtempoon Fossil fuels could have been left in the dust 25 years ago

Germany did investing, but China ate the market. It's basically what happened in the 21th.

It's also interesting that we're talking about 1980/90. 25 years ago is 1999.

logtempoon Fossil fuels could have been left in the dust 25 years ago

We're not able to left it in the dust today, how could we have done so 25 years ago?

"we" should have, but "we" could not.

logtempoon Cement recycling method could help solve one of the big climate challenges

It's math time, let's look what wikipedia say about electric arc furnace:

- 1.44 gigajoules (0.4MWh) is required for 1 ton of steel. In theory.

- 300T of steel needs 132 MWh, and a "power-on time" (the time that steel is being melted with an arc) of approximately 37 minutes.

---- wikipedia end -----

From https://ourworldindata.org/grapher/electricity-prod-source-s...: total world electricity from renewable was 10,700TWh in 2021. 11,600 TWh in 2023.

1.5 billions (metric) tons of crude steel were produced in 2023. 30% of it by electric power.

------------------------

(A) Let's assume that 20% of those 30% already come from renewable (which is not the case, anyway). 30x20% is 6%. It means 24% of the 1.5 billions tons are looking for renewable.

It means 360 millions of tons needs its green energy.

It means we need to find 360 millions x 0.4MWh = 144 TWh.

If we don't assume (A), we get 152 TWh.

It means we need to dedicate ~1.5% of renewable worldwide energy to replace 24% of crude steel "e-production". In theory...

We observed +5% of renewable energy production worldwide. If we wanted to make the steel *production* go green (1.5*3.33 = 5%), in theory it could be possible in one year...in theory.

Tbh, I expected a more crazy conclusion. I'm quite sure the number is off by more than 10% though. But even if it was off by 100%, it would mean it's possible in 2 years.

On a side note: it's useless anyway if those 5% are not coming with a decrease of 5% of coil&gas consumption. Which is not what's happening...

Feel free to redo the math, I can make a mistake!

logtempoon DuckDuckGo was down

duckduckgo don't prevent website to track you or deposit cookies etc. Once you're on a website, let's say twitter, duckduckgo does nothing.

> When you view Twitter content such as embedded Tweets, buttons, or timelines integrated into other websites using Twitter for Websites, Twitter may receive information, including the web page you visited, your IP address, browser type, operating system, and cookie information. (https://developer.x.com/en/docs/twitter-for-websites/privacy)

So, if you visit a news paper that have embedded twitter post in it, twitter might know you passed by this website.

logtempoon Shipbreaking

https://m.youtube.com/watch?v=5kDbwE7mFck

I'm sure you mean this one. There are probably others though.

logtempoon California exceeds 100% of energy demand with renewables over a record 30 days

and it's also just an excess during mid-day (excess during .25h up to 6h in the day if I understand correctly) which does not cover the reat of the day through batteries.

It also say "it's only the start, it's going to be more in the future" but tbh I expect hydroelectric power to go down in the future...which represent up to 20% of the demand, and is the most practical renewable source.

Also batteries system is "one of the largest in the world" and barely allow to delay +4h of power...that shows how big is the task.

Title is definitly missleading.

logtempoon Ask HN: How much does the product name matter in the early days? (B2C)

in the mc Donalds movie, at the end one of the founders say that the reason they chose to include Mr Donalds, is because of its name that convey a "USA vibe".

Also, why Apple is called Apple and not Macintosh anymore?

I'm not in marketing, but I think it tells a lot about the importance of a name product/company.

also: https://en.m.wikipedia.org/wiki/Pilsner

I think you should find a name that convey better your product or image of "scientifically based pills that give you nutrients". But bit before the final version of your product/company.

I think actually that for it's even good to change the name during the process, because at first you're going to talk at investors. Which is different than talking to consumers.

on a side note, sci-pills could be a cool name ahah

logtempoon Calculus with Julia

What I mean is as a worker or student, I want to know if the tools I spend time on will be relevant in the industry. And I think I have more chance to meet companies working with MATLAB than Julia.

But if I want to work at asml Julia might be a good fit ofc.

logtempoon Calculus with Julia

Tools are valid regarding a context (when you have a hammer everything is a nail etc.). In the industrial context, Julia is not valid. In the research/education, it is valid. It does not mean that Julia will never be relevant in research.

logtempoon I Went Undercover as a Secret OnlyFans Chatter. It Wasn't Pretty

Makes me think about the movie her, where the main character write love letters for the clients of a website.

logtempoon What are the most visually appealing blogs you've seen?

same. it's relaxing to the eye, the font is monospace I think, the colors are "calm" and it's not a wall of text. It's also fast to load.

logtempoon Sound-suppressing silk can create quiet spaces

Both I'd say. We consider it less than the thermal problem since there is less regulations about noise, and it's also part of how we build today since there is a tradeoff between price, sound isolation and even thermal isolation. But we do have good techniques.

logtempoon Sound-suppressing silk can create quiet spaces

the problem in buildings is the building transmitting vibrations. That's why it's hard to find a solution afterward.

logtempoon New capacitor with 19-times energy density

is it a big deal ? Any components need to pass some conformity tests, and testing capacitors is an established process.

There are bike with supercapacitors out there, so it's definitly not that far from the market.

logtempoon 'Underwater bicycle' propels swimmers forward at superhuman speed

on a bike, we don't use hands to propell ourselves for obvious reason, why they don't also put a crank for the hands too? it double its speed and you can counter balance the legs motion too.

logtempoon Show HN: AI climbing coach – visualize how to climb any route based on your body

I don't see the shape of the holds being a big problem. With some help from indoor companies and hold makers, figuring out which hold model is on the wall should be possible.

As for the usefullness of the software, I'm sceptical too as it don't really solve a problem. But maybe I'm not seeing it and it could be good for beginners :) A good improvement would be adding a comparison between you and the model in term of body position and fluidity of movements.

logtempoon A company is building a giant compressed-air battery in the Australian outback

You don't want to put salt water in the ground. It will destroy either the soil or the aquifer.

logtempoon A company is building a giant compressed-air battery in the Australian outback

also water tend to be scarse nowaday and valuable nowaday.

logtempoon New scanning electron microscope tech sees magnetic field with 100nm resolution

The preprint is freely available, thre are nice pictures where you can see mm/cm-size magnet near the electron beam, over a "G-grid detector" that act like a test pattern in the background.

logtempoon Moving the largest camera from California lab to Andes mountaintop

Doing so requires more than just specially designed lenses and sensors, Utsumi says, because no matter how well designed and built those components are, there will be imperfections. For instance, consider an image taken by an ordinary camera: There will always be some distortions in shape and color near the edges. There will also be slight distortions in the digital sensors as well, and similar effects will hold true for the LSST Camera. "We need to understand what's going on there so we can correct for it."

Utsumi and his team took thousands of images over three months with the LSST Camera sensors of all sorts of shapes and patterns. They then compared the camera's images with the originals to understand how to correct for any distortions or errors. The team has also worked on how to correct other issues, such as the fact that brighter objects appear larger than they actually are, as well as "ghosts," or images of an object that appear because of electronic crosstalk between sensors within the camera.

from https://phys.org/news/2023-09-lsst-camera.html

For the characterization of CCD image sensors, it is the same idea, see for example this company that does CCD testing machine: https://www.ci-systems.com/ccd-testing

For the mirrors, I once visited a lab that does mirrors for astrophysics, and it measure the mirror shape with wave-front instruments (basically it's interferometry, you look at the phase difference of a wave to measure distances).

logtempoon The highest observatory in the world just opened in Chile

Sure, but as you said, there is probably a need of a small crew up there.

logtempoon The highest observatory in the world just opened in Chile

One could bring oxygen up there, with a small respiratory assistance I think it could do the job. But doing it remotely is obviously cheaper anyway, for many reasons.

logtempoon Ask HN: What Linux distribution for desktop are you using?

I've used Linux distro since almost 10 years now. I'm not a poweruser, so I've stick to Ubuntu and Linux mint which is based on ubuntu. It require minimal effort and community is big. If you want to play videogame, I think those are good distrib. Linux mint also install proprietary drivers I think, which is good when talking about gaming.