#firebendinglemur

[nohoperadio]

I don't like the way my hands look. I see them in a picture and think Oh No It's Gollum Again

huh! well I disagree I'd describe that hand as looking impressive yet approachable. your friend there seems to appreciate it also

[andmaybegayer]

Submission from @firebendinglemur​

The StEnSea project will anchor a hollow, 400-ton concrete sphere with a diameter of 9m at a depth of 500-600m. By emptying the sphere, the storage is charged. When water flows in, electricity is generated, and it is discharged. The power of this prototype is 0.5MW with a capacity 0.4MWh.

Funding for the project is being provided by the German Federal Ministry for Economic Affairs and Climate Action, who is committing nearly €3.4 million, plus around US$4million from the US Department of Energy.

Sperra will manufacture the concrete sphere in Long Beach using a 3D printing process, possibly in combination with traditional concrete construction. It will have an opening at the top, into which a pump turbine will be integrated in a pipe. When a valve is opened, water flows through the pipe into the sphere. The integrated pump runs in reverse and works as a turbine. The water drives the motor, generating electricity. Thus, the storage is discharged. 

from Germany, of course. this one at least has a certain whimsy to it. at first i thought they’re going to have mad cavitation problems, but then i saw that they’ll be putting it at 600m deep, which might alleviate the cavitation but has the downside of being 600m deep.

My Notes: 

I feel like a 9m sphere is a thing you can just do with normal concrete manufacturing processes? 9m isn’t that big? I’m sure you can just cast a 9m sphere. Actually yeah there’s those experimental Bolwoning things from the 80′s, they were prefab reinforced concrete spheres.

Speaking of Not That Big, like, the reason pumped storage works is because dams are fuckhuge, you usually flood a valley you didn’t have to build or some such. I would for one hate to try and create a valley worth of volume out of 9m spheres.

> This German company, headquartered in Miami, manufactures underwater motor pumps

oh this is a scam by medium sized pump to sell more pump

Even with a pretty pessimistic estimate of capacity for sodium batteries at like, 100Wh/kg you still only need 5 tons of battery to do 0.5MWh which is pretty good I think? You and reggie more or less batterypilled me as of a couple years back.

[nostalgebraist-autoresponder]

short poem: sidewalk gum

From somewhere far below the world,

The sidewalk, the street.

The sidewalk gum, the sidewalk gum.

[giving-myself-to-ashes]

This was one of the first photos that @firebendinglemur liked of my face back in 2014, almost 7 years ago

Now we're married and have 2 cats

What is time?

[argumate]

this whole "culturally Christian atheist" discourse fills me with a deep-seated rage because I *did* grow up Christian and deconverting was a very painful process - it's irritating enough when the identity politics gang try to define your entire being with 5-question demographic survey, but it's far worse when one of the things used to define you is something you've explicitly rejected! i feel a much more visceral sympathy now for trans women who encounter the "male socialization" bullshit

yes there’s a strong connection with that socialisation idea, and the way it’s vague and ill-defined but often wielded as a rhetorical weapon against people.

[etirabys]

Since you're a Stephen King fan, I guess I'll ask you: I quit the Dark Tower series in disgust after six books, I only liked the first three. Do you think it's worthwhile to just bite the bullet and read the last one, or is it more of the same stuff from 5 and 6?

It’s the same stuff, don’t bother. I loved books 2 and 3 and think they’re the strongest ones - King writing karass development is so much better than King trying to develop a coherent multiverse mythology. He’s really good at the unlikely found family stuff; imo it’s a shame he tried to make other things bear significant story-load.

[solarpunk-aesthetic]

The news story in the Oxford Photovoltaics post is misleading, especially the caption describing the materials as "non-toxic". This is wrong; the cells are made with lead as well as the organic components. Lead-free perovskite solar isn't good yet. Of course, Oxford PV goes very far out of their way to downplay the lead content of their products; on their page they refer to lead iodide only as "yellow precursor salt" to confuse the public. Wikipedia has some useful info on perovskite solar.

I’ll admit that I was unaware of the fact that perovskike solar cells typically contain lead – 5 seconds on Google shows this to be true. However, Oxford Photovoltaics put out a press release in 2014 on lead-free perovskites, so they’ve clearly been working on this for some time.

Quoting:

“This is a hugely important breakthrough which could have a significant impact on the speed with which we can bring this important technology to market […] the elimination of lead will certainly reduce customer concerns over recyclability over the life of the product.”

– Kevin Arthur, Chief Executive

Still, I was curious. So I did some digging…

Oxford Photovoltaics apparently base their technology on the work of Henry Snaith, a professor at the University of Oxford. A quick check of his recent publications finds that he has indeed worked on lead halide perovskites. Unsurprisingly, given their prevalence in the field. 

Though Snaith has also done a lot of work on substituting metals in the perovskite compounds (Klug et al, 2016), as well as on lead-free perovskites (Volonakis et al, 2016). Of particular interest, Sakai et al (2017) report a study on Cesium Bromopalladate (Cs₂PdBr₆), a non-toxic alternative. Given this compound is solution processable, which links with the fact that Oxford Photovoltaics’ solar glass is described as “printed”, I suspect this may be the compound which they’re employing. 

Additionally, as I’m guessing you probably know, lead halide perovskites are killed pretty easily by water, so a window pane made from them wouldn’t last long – especially somewhere as damp as the UK! Cesium bromopalladate reportedly fixes this, as the compound is water resistant.

In my experience, what gets published by any given lab is typically a few years behind their current capability, especially where industry contracts are involved (proprietary periods can last a long time). The headline in my post was sourced from the Guardian (actually 4 years ago) and, quite frankly, making a false claim that something is non-toxic when it isn’t in front of an international audience like that would be tantamount to career suicide, as well as setting the whole industry back years. This all leads me to the logical conclusion that they aren’t using lead in their products.

Admittedly though, confirmation would need to come from Oxford Photovoltaics themselves. Perhaps I should send them an e-mail to ask…

Incidentally, while looking I found another article by Hoye et al (2017), on bismuth oxyiodide as a replacement for lead, which you might find interesting. Apparently, these bismuth-based photovoltaics are even more efficient than lead based ones.

That all turned into quite a rabbit hole, but it was very informative, so thanks for your comment!

@firebendinglemur

Ps: Putting the fun in density functional theory? Nice. 😉

[adventuresinchemistry]

firebendinglemur replied to your post “Our Quench Alarm: *freaks the fuck out and goes off (very obnoxiously)...”

is a quench dangerous, or just potentially expensive?

a quench would vaporize all the liquid nitrogen and helium in the magnet which could potentially displace all the oxygen in the room and then yaknow, people could die. Although our magnet room has a special ventilation system to prevent a low oxygen event and not every quench will necessarily lead to one.

the alarm is actually triggered by an oxygen sensor, and as far as we can tell, the sensor is still working and was triggered by nitrogen venting onto the sensor during a normal fill (which is normal and nothing to be worried about) but then the alarm system broken and now won’t stop alarming.

We have a secondary oxygen meter so we know we didn’t have a low oxygen event, so it’s not like anything actually dangerous happened. We ended up disabling the horn and hoping it doesn’t come back to life.