Wikipedia:Reference desk/Archives/Science/2023 April 27

= April 27 =

Translating a presumed typo
I'm working on an article about a series of bombings in 1970s California. The first news article I've found with any level of detail about the bombs says that an IRS (Internal Revenue Service) investigator thinks the bomb was "probably made of amtho and dynamite." Any ideas about "amtho" in this context? TIA! jengod (talk) 01:28, 27 April 2023 (UTC)
 * It's gotta be referring to ammonium nitrate. Abductive  (reasoning) 01:57, 27 April 2023 (UTC)
 * Ah, now that I clicked the link, probably ANFO misheard by a reporter. Abductive  (reasoning) 02:00, 27 April 2023 (UTC)
 * Oh that looks like a winner. Thank you v much for your contribution to this episode of Wikipedia Cold Case Detectives LOL. :) jengod (talk) 02:08, 27 April 2023 (UTC)

Melanoma and Parkinson's Disease
A paper published in 2009 says:

"there appears to be an increased risk in the development of melanomas in patients with PD [Parkinson's Disease]... It is not known which factors are responsible for this increase in the development of melanomas in PD patients and this needs further investigation."

Has such investigation occurred? What is the up-to-date view? -- Andy Mabbett ( Pigsonthewing ); Talk to Andy; Andy's edits 11:33, 27 April 2023 (UTC)


 * Yes:
 * Brief overview from above sources {Perplexity.AI) --136.56.52.157 (talk) 12:36, 27 April 2023 (UTC)

Discussion continued at Talk:Parkinson's disease. Sandy Georgia (Talk)  13:42, 29 April 2023 (UTC)

What's the point of green hydrogen?
If we get our hands on electricity, which we can use to heat, move vehicles, run devices, generate light, and so on; why would we go the route of putting it into electrolysis (some loss through heat), losing some of it to compress the hydrogen, lose more of it through inevitable leaks, some more through accidents, then lose more of it at the end point? And maybe even transform it into electricity again!

Wouldn't it be much easier to electrify the whole chain instead of "hydrogenize" it? Bumptump (talk) 16:03, 27 April 2023 (UTC)


 * Electric car batteries require large amounts of somewhat rare metals, such as lithium, nickel and cobalt. Even setting aside concerns over the environmental and human-rights impact of mining for these, we may simply not be able to produce enough in time to cater for the needs of the transition from fossil fuel to other power sources. --Lambiam 16:19, 27 April 2023 (UTC)


 * Hydrogen fuel cells are a non-greenhouse-gas-emitting means of powering automobiles, which is the primary use case for hydrogen. The problem with automobiles is they need a means of storing enough energy to allow them to travel a reasonable distance (something in the 200-300 mile range) to be a viable fuel source.  The current non-emitting source is storage batteries, but those have issues and externalities of their own, including the problems in extracting, refining, and using the raw materials to build them, and on the flip side, in recycling or disposing of them when they are at the end of their life cycle.  Fuel cells are an alternate way of doing the same thing, but have less issues than batteries do; the main problem with hydrogen currently is the lack of any infrastructure to deliver hydrogen in terms of fueling stations.  Even battery charging infrastructure, while still lacking, has been much easier to set up than an entire hydrogen storage-and-delivery infrastructure.  Indeed, that barrier to entry, more than anything else, is the main problem with hydrogen.  -- Jayron 32 16:35, 27 April 2023 (UTC)
 * The idea of storing the supply in the vehicle between charges relates to the energy density--how much energy you can get from a given mass or volume of "cylinder of H2" vs "battery". That article I linked has some data tables and related discussion. DMacks (talk) 18:13, 27 April 2023 (UTC)
 * Also important is efficiency. If hydrogen is half as energy dense as, say, gasoline but twice as efficient in terms of losses not used in propelling the vehicle, the effects cancel.  -- Jayron 32 18:22, 27 April 2023 (UTC)


 * Renewable energy sources are generally intermittent. Solar panels produce nothing at all half of the time (when it's night) and almost nothing another quarter of the time (when it's overcast). Wind is slightly better. Spreading your solar panels and wind turbines over a large area helps a bit, but this area has to be pretty big with big transmission lines going all over the place.
 * So to ensure that at least 80% of the time your renewable energy sources produce all that you need, you have to install far more production capacity than your typical demand, so that a large fraction of the time your producers produce far more electric power than needed. You can either shut down some solar panels and wind turbines, wasting some potential production, or spend it on some inefficient process, not wasting it entirely. Making hydrogen may be inefficient, but it's better than not using the energy at all. The hydrogen can then be used to produce some electricity when intermittent production is low. Hydrogen may be inefficient storage of electricity, but it's better than no storage at all, and doesn't require the expensive raw materials of batteries.
 * Furthermore, hydrogen is an important feedstock for the chemical industry and can be used as energy source for mobile applications, in particular ships. There have been some experimental hydrogen-powered fixed-wing aircraft, but storage volume is an issue. Airships can afford the volume to store it at standard pressure and temperature, but airships aren't very practical. Hydrogen lorries could be useful, avoiding heavy battery packs that eat away much payload capacity. Or just add overhead wires to the motorways, so that electric lorries can recharge their last-mile batteries on the move. Hydrogen powered trains are silly. Just use overhead wires; most trains do so already. PiusImpavidus (talk) 19:46, 27 April 2023 (UTC)
 * Basically two things: storage and transportation.
 * Storage: E.g. if you have solar energy you need a way to store it if you want to use it when the sun doesn't shine. The same goes for wind energy when there is no wind.
 * Transport: The renewable energy source is not always where the energy is needed. E.g. you could place solar panels in the desert. But then you need a way to transport the energy. That can be done via hydrogen pipelines or transport vehicles. -- Random person no 362478479 (talk) 19:49, 27 April 2023 (UTC)
 * Hydrogen powered trains do have a sensible use where there is an infrequent service over a long distance. The capital cost of installing the overhead (or third rail) and the transmission losses can become ridiculous for one railcar per day. Today diesel, tomorrow perhaps hydrogen? Martin of Sheffield (talk) 22:02, 27 April 2023 (UTC)
 * Maybe, but at one railcar per day, why use rail at all? Now, maybe someone in the past handed you a non-electric railway, in days when that made sense at that location, and maybe there's a sweet spot in traffic density and distance where hydrogen outperforms overhead wires, batteries and road transport, but this would be so rare that your average railway company has one hydrogen railcar, one spare and one mechanic who knows how to fix it. I doubt it's worth developing new technology for that. PiusImpavidus (talk) 09:06, 28 April 2023 (UTC)
 * One useful thing is to use it to make easily transportable and widely used ammonia. There's a lot of taxpayer money being spent on green hydrogen, hence the enthusiasm from some people. Greglocock (talk) 22:57, 27 April 2023 (UTC)
 * Hydrogen as energy storage is probably not going to be a big thing for the reasons discussed. However hydrogen is used for lots of other stuff, and right now it's mostly produced by steam reforming of natural gas, because this is the cheapest way currently. Doing this via some method that doesn't contribute to global warming is preferable. (One use: speaking of electricity did you know large turbogenerators are generally filled with hydrogen for coolant and insulation? Though apparently a lot of that is produced by electrolysis already as-needed.) --47.155.41.201 (talk) 04:45, 29 April 2023 (UTC)