Science desk
< June 17	<< May \| June \| Jul >>	June 19 >

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is a transcluded archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

June 18

Keeping petrol in glass bottle

I have kept extra petrol in glass bottle instead of fuel container. How long can it be kept which can be used for fuel for motorcycle? I have seen that in laboratory chemicals are kept in glass instead of plastic. So, I though petrol will have longer life, if I keep in glass bottle. — Preceding unsigned comment added by MartinSean56 (talk • contribs) 02:17, 18 June 2020 (UTC)[reply]

You won't be able to keep it after you bump the bottle and it falls and breaks, especially if the spilled petrol touches something that ignites it. --76.71.5.208 (talk) 03:52, 18 June 2020 (UTC)[reply]

Don't most gas stations post warnings to store gasoline only in "approved containers"? (Typically metal or plastic.) ←Baseball Bugs ^{What's up, Doc?} carrots→ 05:23, 18 June 2020 (UTC)[reply]

There was a time when pumps had a clear glass cylinder or other shape at the top that fuel passed through on its way to your car. The glass was supposed to be inert to petrol. That's not a storage situation, but constantly exposed. HiLo48 (talk) 05:52, 18 June 2020 (UTC)[reply]

According to Fuel dispenser, that glass cylinder had a scale on it so you could figure out how much you wanted and then let it pour into the tank. That less-than-safe approach was abandoned once modern dispensers were invented. ←Baseball Bugs ^{What's up, Doc?} carrots→ 07:56, 18 June 2020 (UTC)[reply]

Many sites state explicitly, without giving a reason, that glass is not suitable for storing gasoline. I guess that the safety concern of the glass breaking is a major factor; but being subjected to light will make the gasoline oxidize more quickly. The glass would not react with any of the components of the gasoline, but gasoline has a limited shelf life anyway, typically given as six months,^[1][2][3] or shorter if exposed to higher temperatures like 30 °C (86 °F). Please read this WikiHow article on storing gasoline. --Lambiam 06:15, 18 June 2020 (UTC)[reply]

Also see Molotov cocktail. As explained here --Guy Macon (talk) 12:20, 18 June 2020 (UTC)[reply]

Petrol/gasoline will "degrade" over time regardless of what you store it in, because the different components—including water and fuel additives—will separate. For long-term storage you should add a fuel stabilizer if you intend to eventually use it as fuel. Besides that, as others have stated, use an approved storage container. Safety is the major concern, as petrol is volatile and spilled fuel will produce flammable vapors. Most safety regulations are written in blood, as the saying goes. Evaporated fuel is also bad to inhale and contributes to air pollution.

Don't take this personally, but the logical fallacy you fell prey to here is hasty generalization. Some laboratory chemicals are stored in glass, as you correctly note, but that does not logically imply that glass is the best material for storing any chemical. Hydrofluoric acid dissolves glass; you can bet no one is storing that in a glass container! And for anecdote, I've seen plastic containers used for laboratory storage, including storage of solid chemicals. (Not all chemicals are liquid at room temperature, of course.) You may find chemist Derek Lowe's "Things I Won't Work With" posts, which discuss some rather dangerous chemicals, amusing and edifying. --47.146.63.87 (talk) 01:53, 19 June 2020 (UTC)[reply]

I have kept petrol in an approved plastic container. It produced a lot of vapour, expanded in warm weather causing the container to bulge, and eventually lost a substantial proportion due to evaporation and escaping through the seal on the container. I'm wondering if this indicates a problem with storing in a glass bottle/jar - could the the increased pressure mean that a rigid glass jar or bottle (likely with an airtight seal) might burst? Iapetus (talk) 10:00, 20 June 2020 (UTC)[reply]

Nickel(II) perbromate

Nickel(II) perbromate hexahydrate, is known: [4]. Can this compound green? Thanks for much. (Sorry if you don't understand, because my English is not good). Ccv2020 (talk) 06:46, 18 June 2020 (UTC)[reply]

Why? —OuroborosCobra (talk) 10:20, 18 June 2020 (UTC)[reply]

I'm reminded of this classic comedy scene. Apologies. PaleCloudedWhite (talk) 10:31, 18 June 2020 (UTC)[reply]

While I thought of this: [5] --Khajidha (talk) 22:36, 21 June 2020 (UTC)[reply]

Nickel(II) hexahydrate compounds are green, if the anion is not adding colour. (also subject to appropriate lighting and lack of colour blindness of observer) Often with the crystallographic data there is a .cif file that has some information, including crystal colour. But here it is missing. But due to this question, I will add the material to Nickel oxyacid salts. Graeme Bartlett (talk) 10:47, 23 June 2020 (UTC)[reply]

Equipment sound

Which device produces this melody in the video? Seemingly sort of medical equipment, not sure if this comes from artificial ventilation. Thanks. 212.180.235.46 (talk) 12:25, 18 June 2020 (UTC)[reply]

VIEWER WARNING, the video linked to above shows images of surgery. Thanks. Anton Anton.Brad (talk) 12:35, 18 June 2020 (UTC)[reply]

Specifically, it purports to show the Azerbaijani entertainer Bahram Bagirzade being intubated. Our article mentions that he was diagnosed with COVID-19 on June 7 and his situation became critical on June 14.

I put all the video's comments through a translator. Most are understandably emotional and range from wishes, prayers, and expressions of dismay for Bahram and for the nation, through debates over the video's authenticity and appropriateness, to discussions of COVID-19 itself. The only mention of the sound is:

Nuray Guseynova: I don't understand the purpose for which it is shared and the music that goes in the background ... God bless everyone ... He has a family and children ...

ANGEL PRO: If I'm not mistaken, the sound of the device is not music.

Nuray Guseynova: @ANGEL PRO I came to that conclusion

The noise is very curious and does sound nearly nondiegetic. There are a couple of jump cuts (at 0:08, 0:14, 0:25, & 0:55), yet there are no discontinuities in the audio (either of the melodic tones or of the other background noises). I assume that a full 1:22 of audio of the scene was use, which may or may not be synchronized with any one of the video segments, but that the noise, as melodic as it is, most likely is diegetic and produced by one of the medical devices. It does have a hypnotic quality. -- ToE 21:30, 18 June 2020 (UTC)[reply]

It could be any number of things, but it is clearly not being attended to by the doctors who are busy actually trying to save somebody.

Hospitals are full of equipment that buzzes, beeps, honks, etc. and are ignored by everyone working there. In most cases the "silence alarm" function only stops the noise for a short amount of time. One of these days, some regulators in the US or the EU are going to realize that we are simply training people to ignore alarms, and make it so

Heart just stopped = Loud alarm.
Heart stopped an hour ago = silence.
Sensor fell off or was unplugged, one soft beep then silence with a flashing light.
battery getting low = flashing light.

Until then, every emergency room and intensive care unit will have constant alarms that everybody ignores. --Guy Macon (talk) 13:41, 18 June 2020 (UTC)[reply]

They may have learned to tune out the noises that they know are not a problem. Just like you have to tune out background noise at your own place of business. ←Baseball Bugs ^{What's up, Doc?} carrots→ 14:02, 18 June 2020 (UTC)[reply]

In the same way that most regulars to the reference desk block out any comments by Baseball Bugs. — Preceding unsigned comment added by Anton.Brad (talk • contribs) 08:48, 19 June 2020 (UTC)[reply]

"Ooh, burn" (Questionable Content 4285) {The poster formerly known as 87.81.230.195} 90.203.10.153 (talk) 20:04, 19 June 2020 (UTC)[reply]

I see they have the machine that goes ping!. DMacks (talk) 14:14, 18 June 2020 (UTC)[reply]

I'm aware of buzzes, etc, but personally I've never heard that peculiar ringtone-like melody in medical setting. Sounds quite specific and it caught my attention. 212.180.235.46 (talk) 17:26, 18 June 2020 (UTC)[reply]

It is indeed unusual. I happen to have had the dubious honor of being in an emergency room, intensive care, and then a regular hospital bed here in California. Nothing sounded anything like that. Yet in this video you not only hear it from somewhere close, you also hear it from multiple sources in the background. Do we know what country this is? A lot of eastern European countries have their own brands of computers, medical equipment, etc. --Guy Macon (talk) 04:10, 19 June 2020 (UTC)[reply]

It's in Azerbaijan and almost certainly a COVID-19 treatment. Today in a CNN news coverage I heard a similar melody in a COVID-19 treatment room in Portugal, so probably some sort of the related equipment. 212.180.235.46 (talk) 12:08, 19 June 2020 (UTC)[reply]

The specific procedure performed is that of providing ECMO support. The patient's condition, although stable at the moment, is still serious; it is not possible yet to say whether his lung function can be restored. --Lambiam 13:02, 19 June 2020 (UTC)[reply]

You can see samples of alarms based on some 2010 or earlier version IEC 60601-1-8 here [6]. None of those sounds seem the same, but my ability to recognise tones isn't very good. However as per that and [7] + [8]there is also some flexibility in certain aspects which I don't entirely understand anyway, and it seems that some places still allow proprietary alarms especially if they've been shown to perform similar to the IEC alarsm. It seems the standard is fairly controversial [9] with people looking into alternatives [10] [11], although those definitely don't sound like one of the more popular proposed alternatives, auditory icons [12] Nil Einne (talk) 12:57, 19 June 2020 (UTC)[reply]

I was thinking ventilation seemed the most likely and most similar and I finally found [13] which seems to be very similar to what we are (I think) talking about. (I found it difficult to search for this question since most content is how to manage alarms, e.g. set them, and handle them when they occur etc.) BTW, the person talking sounds American and from what I can tell the device is or was sold in the US [14] [15] so I assume that some US hospitals have similar alarms. (And I don't think it's unique to that particular instrument either, actually there's a fair chance the ones in the Azerbaijani hospital are different.) Nil Einne (talk) 13:18, 19 June 2020 (UTC)[reply]

Yes, sounds much like that device. Thanks! 212.180.235.46 (talk) 15:05, 19 June 2020 (UTC)[reply]

There are several YouTube videos on hospital sounds and ICU sounds. Search for "hospital ambiance", "background noise", "bedside life support", "sounds of the ICU". Bus stop (talk) 13:25, 21 June 2020 (UTC)[reply]

Covid-19 current scientific knowledge on critical patients

Is it known whether critical Covid-19 cases can be largely clear of viral infection? Is there any consensus on this within the scientific community? And is focus for therapeutics still focused on both anti inflammatories and anti Virals? Clover345 (talk) 13:26, 18 June 2020 (UTC)[reply]

I take it that you've seen this and this? Alansplodge (talk) 13:45, 18 June 2020 (UTC)[reply]

This study showed high viral load and viral shedding in clinical samples from a group of 16 critically ill patients. Low outliers were not reported. See Figure 1A in the article, but note that low Ct values mean high viral levels. --Lambiam 14:24, 18 June 2020 (UTC)[reply]

Petrol (gasoline) becoming unusable over time

I recently purchased a second-hand lawnmower. The vendor told me that it was in top condition but had been sitting idle for over 6 months, and so I would need to empty the fuel tank and refill it with new petrol. I asked why, and was told that petrol that's over 3 months old is contraindicated.

Is this true, and why? I can understand fuel stored in a transparent container like glass might oxidise or something, but inside a completely dark metal tank in a lawnmower is another story altogether. -- Jack of Oz ^{[pleasantries]} 23:09, 18 June 2020 (UTC)[reply]

There's a bit on this at gasoline#Stability. It says there When gasoline is not stored correctly, gums and solids may result, which can corrode system components and accumulate on wetted surfaces, resulting in a condition called "stale fuel".

What it doesn't really say is why this should happen. My guess is that it's the fault of unsaturated hydrocarbons in the mix, which may polymerize. Probably producers try to deliver a product composed mostly of saturated hydrocarbons, but not 100%, because unsaturated hydrocarbons can help to raise the octane number. --Trovatore (talk) 23:24, 18 June 2020 (UTC)[reply]

The RAC say petrol in a sealed container can be stored for six months at 20°C, three months at 30°C. Less if the seal is poor. They also say use of old fuel can cause damage to the engine. See this page. DuncanHill (talk) 23:35, 18 June 2020 (UTC)[reply]

The tank on a lawnmower will be vented, and this shortens the shelf-life of the petrol further. There's an article here from a garden machinery supplier with further information. DuncanHill (talk) 23:38, 18 June 2020 (UTC)[reply]

The process of degradation producing gums and solids is autoxidation.[16] --Lambiam 23:55, 18 June 2020 (UTC)[reply]

Gasoline can be conserved several years in an absolutely air tight container. In a common canister or the car tank beside oxydation and polymerization the most volatile (and flammable) components will evaporate quickly and after two or three months your gasoline will not burn well any more. 2003:F5:6F06:8700:A55E:59B6:FAEF:B44D (talk) 00:11, 19 June 2020 (UTC) Marco PB[reply]

Thanks. All good information. -- Jack of Oz ^{[pleasantries]} 00:33, 19 June 2020 (UTC)[reply]

Resolved

It's not just autooxidation. Unless the gasoline is stored under vacuum or an inert atmosphere, it will be exposed to the air and react with oxygen over time. Also, gasoline sold as fuel is not pure gasoline; it contains various fuel additives. In a lot of countries this will include ethanol. This forms an emulsion, and as it sits the components slowly separate into phases; if you then try to run an engine on this, it can clog the fuel system or fail to burn in the engine. Fuel stabilizers contain things like emulsifiers to inhibit this separation. --47.146.63.87 (talk) 19:53, 19 June 2020 (UTC)[reply]

Couldn't that problem be simply resolved by stirring the fuel so that the components re-combine? -- Jack of Oz ^{[pleasantries]} 21:33, 19 June 2020 (UTC)[reply]

Maybe. First step: drain the whole fuel tank and fuel system. Hopefully you don't leave any gums or other residue behind, because now you need the fuel system flushed as well. The original question asked about a gasoline-powered lawnmower. --47.146.63.87 (talk) 07:37, 20 June 2020 (UTC)[reply]

Autoxidation is an irreversible chemical process. Stirring may perhaps reduce the adverse impact of the fuel containing gum precipitate, but it will not dissolve the gum. --Lambiam 08:40, 20 June 2020 (UTC)[reply]