Dark in the context of astrophysics means specifically that the object/matter does not interact directly with electromagnetic radiation (eg absorb an optical/microwave/radio photon). So it is probably dark matter, but probably unlikely to be a black hole because we can typically detect a black hole's effects in an indirect manner :P
"dim" implies "there is something normal there that is just not emitting light". "dark" in this astronomical sense means essentially "dim and completely transparent" which is not what you get with e.g. a cold gas cloud - those are opaque.
It's not just that. Remember that in space distance doesn't attenuate electromagnetic radiation. Given perfect line of sight, you could broadcast a 1mW 5GHz signal across the empty space between galaxies and have perfect reception (provided you're very patient)
One also has to consider that at this scale, you cannot have a normal interaction with the EMF and be dim. The normal physical processes of matter at the scale of 1 million suns ends up being quite loud. Black holes that aren't actively eating things form an exception, but black holes aren't normally dark either. Whatever this is it's peculiar, but I wouldn't write-off that it might be an issue with the model they developed for interpreting the data.
sounds like you're arguing that it should be open given that two non-profits and the US government are the primary funders of it. Given how non-profits tend to get a high degree of public subsidy as well (indirect tax subsidies to non-profits and the people that donate to them are essentially paid by the US taxpayer), we can reasonably conclude that the US taxpayer is footing the bill here.
I'm not here to say it _should_ be open. Instead, I'm saying they offer a valuable, international (global) service and I want their economics to be sustainable, and have personally no objections to them keeping their AI models private if they wish so.
Meanwhile, the whole idea of iNaturalist has evolved around voluntary reporting, community involvement, and open data, and I think some of that needs to stay. They can't turn fully commercial.
I think the problem for me here is that previous you mentioned yourself that the primary funders are nonprofits and government organizations (NSF, Nat Geo Society, Gordon & Betty), so it doesn't seem like even you believe the private commercial piece of the puzzle is very large. I doubt allowing the models to be open would sabotage the work they do with any of the aforementioned organizations, or hurt their ability to target future government/non-profits.
If in fact what you said is true about the sources of funding, it would then seem that the US taxpayers (the relevant party here) are footing a large part of the bill from direct and indirect subsidies. I feel that it can be reasonably argued that a non-profit organization that is benefiting from significant public subsidy should make their model available for public use.
I have to imagine that even accounting for the variance in internal resistance over a large set of batteries in a demanding application like a car is probably a host of problems makes this unattractive from the outset.
seemed like they were pointing out that Mazda EV offerings are bad and that they don't worry about EV initiatives. That doesn't have much to do with studying how to put older batteries to use - EVs can be bad for many reasons.
To me it seems perfectly reasonable to try to find a way to leverage depleted EV batteries for a factory - whether or not it's producing EVs or not.
Is that much of a problem for a catalyst? Presumably you do not need many of these: at water treatment plants and at the waste-stream for manufacturing processes which emit PFAS. You might not be able to justify the expense inside your home water purification system, but it could still be cost effective for large scale installations.
You would need a lot of catalyst because the water infrastructure to supply several hundred million people in the US is massive, let alone the rest of the world.
The problem with those catalysts is that the latter two are minor components of platinum and copper/nickel ores and despite how expensive they are, the extraction is only economically viable as part of other mining. Their supply can only grow as much as platinum extraction allows and demand is already pretty significant with environmental regulations often necessitating their use. Any more demand for them will cause their prices to rise dramatically and its a long way before they become profitable enough to mine on their own (flooding the platinum market in the process which has much higher yields from the ores).
it depends on the scale and the required amounts. If having a limited amount of catalyst wasn't such a big problem I suspect hydrogen power would have been much more economically viable.
Activated carbon filtering removes up to about 75% of PFAS. Reverse-osmosis removes almost all.
Doesn't get rid of them, to be clear. It would still be better if a way could be found to chemically (and cheaply) convert them to something less harmful.
> Activated carbon filtering removes up to about 75% of PFAS
Common inexpensive non-RO filter systems come with independent test results showing 99% removal of PFOA/PFOS (see e.g https://www.brondell.com/content/UC300_Coral_PDS.pdf). Do we have reason to believe that other PFAS don't filter as easily?
