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October 28

Fuel efficiency (auto milage)

All else being equal, does the standard fuel-using car travel further on higher octaine gas (petrol) than on “regular” gas?DOR (HK) (talk) 19:31, 28 October 2019 (UTC)[reply]

As long as you are using the minimum-required octane for the vehicle, no, though this is a common misconception. Octane rating: higher-octane fuel can be compressed more without autoignition; engine knocking occurs when the fuel detonates prematurely on its own (due to being compressed and heated), rather than by the spark plug. High-performance Otto cycle engines typically have higher compression ratios, which means the fuel needs to withstand higher pressures and temperatures without autoigniting, meaning a higher octane number. Putting fuel with a higher-than-required octane number in a typical engine does nothing other than make the engine burn more expensive fuel; the engine is incapable of compressing the fuel more, which is what is necessary to achieve better performance. (I'm sure there are some exotic engines with adjustable compression ratios, but of course you specified a "standard" vehicle.)

Potential article improvement: anyone think octane number or another article should state this explicitly? --47.146.63.87 (talk) 00:46, 29 October 2019 (UTC)[reply]

Also you need more energy to ignite it, which is drawn from the battery, whose power is in turn refilled via dynamo by burning fuel. So you'll actually get slightly worse mileage. You need to have good enough gas to avoid unpredictable autoignition since the power it creates doesn't go fully into turning the crankshaft but is wasted on the engine walls (and causes long term damage), but once you've minimized the occurence of that there are no benefits on mileage for using better and better gas. 93.136.155.134 (talk) 01:32, 29 October 2019 (UTC)[reply]

Computers that adjust compression via timing are not exotic. For example, the very common Dodge 5.7 V8 has variable timing (and it shifts into 4 cylinder mode when all 8 aren't needed). 2600:1004:B022:5255:7A88:5987:105B:29D9 (talk) 09:44, 29 October 2019 (UTC)[reply]

Hmm, the Dodge 5.7L Hemi? That does have variable displacement, but does adjusting the ignition timing actually change the compression ratio? It looks like you need to actually change the engine geometry to do that. I found the article on such engines: variable compression ratio. --47.146.63.87 (talk) 20:13, 29 October 2019 (UTC)[reply]

If you fire when not at full compression, you effectively change compression. — Preceding unsigned comment added by 12.229.60.66 (talk) 23:35, 29 October 2019 (UTC)[reply]

To be painfully exact... Cylinder compression is based on the geometry. That is one factor of interest in fuel efficiency. Another is cylinder pressure, which based on geometry and the amount of fuel-air injected into the cylinder. The two are often mixed together in conversations. Another is firing time. If you fire early or late, you fire when pressure is not optimum. Further, firing early will likely cause issues with the piston because it is being pushed up by the shaft below and being pushed down by the explosion above. Firing late fires when pressure is lower. This would be equivalent to having a shorter cylinder - which is a different geometry. I personally do not know of any engine that purposely fires late to improve efficiency - but that doesn't mean it doesn't exist. Yet another factor is the spark itself. Too much fuel is injected because the optimal fuel mixture is hard to ignite. A dual-spark system allows you to use less fuel. Some engines have a separate, very small spark chamber that has a high fuel mixture and then very low fuel mix in the large main chamber. The flame from the prespark ignites the main chamber. But, the question is about octane and related fuel efficiency. High octane fuel, by itself, isn't more or less fuel efficient. What high octane fuel allows for is better performance. Simply put, you don't have to push down on the gas pedal as far, so you end up using less fuel. The end goal is to put less gas into the engine. Turning off cylinders is one effective way of doing that. Using one of the many forms of pre-ignition or pre-spark is another. Even a dual-spark plug system helps. Most of all, it is up to the driver. If you are cramming down on the gas pedal, you are using more fuel than you need to use. It isn't the engine's fault. 135.84.167.41 (talk) 14:19, 1 November 2019 (UTC)[reply]

Many thanks for useful and on-topic answers. DOR (HK) (talk) 16:39, 29 October 2019 (UTC)[reply]

October 29

Featured Article

The front page of Wikipedia shows the death date of "Sir" Jimmy Saville. Is this vandalism? Surly we would not show him as a featured person and someone of worth due to his paedophilia? His misbehaviour is also not mentioned in the block of text that comes up when you hover over his name, but rather speaks about his charitable efforts, I would imagine these have been overshadowed. Also, has he not been stripped of his knighthood yet? Thanks Anton 81.131.40.58 (talk) 08:37, 29 October 2019 (UTC)[reply]

Being a featured article only requires that the subject be notable, not that they be "good". This isn't unique to Wikipedia. Time Magazine once named Hitler the Man of the Year: [1]. So, it's basically "Most Significant Man of the Year", not "Best Man of the Year". SinisterLefty (talk) 08:57, 29 October 2019 (UTC)[reply]

I understand that, but still... Anton 81.131.40.58 (talk) 09:22, 29 October 2019 (UTC)[reply]

And to prove that very point-that notability is not necessarily for the right reasons, the front page also shows for 'On this day' the birth date of Joseph Goebbels... Lemon martini (talk) 10:52, 29 October 2019 (UTC)[reply]

The primary purpose of featured articles is not to celebrate the subjects, but rather to demonstrate what well-written articles can look like. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:11, 29 October 2019 (UTC)[reply]

Also, according to the article, there is no process for stripping someone's knighthood posthumously. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:13, 29 October 2019 (UTC)[reply]

Just a heads up, I believe we're talking about the selected birth and death anniversaries section of OTD, not the "Featured Article". The Jimmy Saville article is not currently eligible to appear in the Featured Article spot, but only because of the quality of the article itself. ApLundell (talk) 00:10, 30 October 2019 (UTC)[reply]

Daily rates of pay for IT consultants

I'm looking for an approximate idea of the current market rates for IT consultants, in various countries and at various levels of expertise (e.g. senior manager, manager, senior analyst, junior analyst, etc). Where can I find such information? I realize of course that this is commercially sensitive information and may not be publicly available. Thanks, --Viennese Waltz 12:47, 29 October 2019 (UTC)[reply]

Here is a searchable database, by geography, but it may be limited to the US. --Jayron 32 13:26, 29 October 2019 (UTC)[reply]

October 30

TeamTrees

Should the TeamTrees project have its own article? It's getting quite big on YouTube. 113.23.6.77 (talk) 16:25, 30 October 2019 (UTC)[reply]

If there's enough reliable sources, an article can be made - be WP:BOLD and do it yourself if you think that makes sense. However, the existing article doesn't seem to have an overwhelming amount of space devoted to it, nor an over-abundance of references devoted to it. In cases like that, it's often better to update the existing article until it becomes obvious that a split is required. Matt Deres (talk) 16:45, 30 October 2019 (UTC)[reply]

See WP:42. The decision to make an article depends on whether or not you can find enough reliable source text that you can cite when writing the article. If there are enough good sources that you can write a reasonable-length article on any subject using those sources, then get on it. No one is stopping you. --Jayron 32 16:46, 30 October 2019 (UTC)[reply]

October 31

How did Air Force one go to the Reagan Library?

Reading a news report about the fires in California, I learned that the Reagan Library has a display including the retired Air Force One plane. That plane, VC-137C_SAM_27000, served several presidents, and Reagan was not even the last one. How was it decided that the plane would go to the Reagan library and not to one of the other president's libraries? The articles on the Reagan library and plane doesn't say. RudolfRed (talk) 01:00, 31 October 2019 (UTC)[reply]

As a wild guess, it was the first library which had space for an aircraft, and some plausible route for transporting it there. Andy Dingley (talk) 01:13, 31 October 2019 (UTC)[reply]

That makes sense, thanks. RudolfRed (talk) 03:11, 31 October 2019 (UTC)[reply]

Also to be considered: Reagan was the president to use it the longest (8 years), and while strictly speaking Reagan was not the last president to fly on it, it was replaced as the primary Air Force One in 1990, little more than 1 year after he left office (it remained in service as a backup plane and saw occasional use until 2001, but it was not the primary Presidential plane after 1990). Even if what Andy Dingley says above weren't true, those are two more very good reasons why the plane is specifically associated with President Reagan. --Jayron 32 14:53, 31 October 2019 (UTC)[reply]

There is some discussion here [2] suggesting lobbying by Reagan (and I guess his supporters), starting before the end of his presidency, was the main factor. That said, as Jayron32 said, Reagan also seemed to be the with perhaps the biggest claim which would also likely have affected any lobbying. It was only used during a small part of Richard Nixon's presidency and his resignation and what lead up to it likely was a major factor against his library being able to claim it. Gerald Ford was unfortunately for him, probably also somewhat tainted by Reagan and the pardon (whether or not it was wrong), and more importantly was not elected president or even vice president and also had a very short tenure. Jimmy Carter had a longer tenure but still only a term. He also remained more active in areas which may have caused controversy. It was only the primary plane during part of George H. W. Bush's term and in addition he only served one term. The fact that his son was the current president was probably more of a hindrance than a help. Bill Clinton was the only one to serve 2 full terms (at the time) but the plane wasn't the primary plane during any of his presidency, he was impeached even if not convicted (whatever people think about the rights of that), his wife was a senator and his library had only just broken ground. Oh and I realised after posting I forgot to write about George W. Bush but it was only used as the non primary plane during a tiny part of is eventually 2 term tenure and he was the current president. To be fair, Reagan did have the Iran–Contra affair and other controversies but still..... To put it a different way, although I personally dislike a fair amount of what Reagan stood for and did, if I were involved in deciding who to give it to Reagan would seem the least controversial choice out of all the other ones. The alternative was to give it to no one. Or to split it up in some way, but that's not likely to work so well. Nil Einne (talk) 07:19, 1 November 2019 (UTC)[reply]

One more forgotten Top Gear controversy

Usually, Jeremy Clarkson is the one who comes to mind when thinking about Top Gear controversies. But I also remember an episode where James May smoothly incorporates several Nazi slogans (of the work sets you free, strength through joy type) into his part of the dialogue. But which episode was it? Thanks in advance -- 77.185.18.44 (talk) 15:38, 31 October 2019 (UTC)[reply]

Top_Gear_controversies#Series_13 Nanonic (talk) 15:43, 31 October 2019 (UTC)[reply]

That’s not what I meant. I think it was a travel/camping episode (?). -- 77.185.18.44 (talk) 16:31, 31 October 2019 (UTC)[reply]

Might have been the first episode of James May's Cars of the People rather than Top Gear. Lugnuts ^{Fire Walk with Me} 17:15, 31 October 2019 (UTC)[reply]

Nope, definitely an episode of Top Gear I have in mind. -- 77.185.18.44 (talk) 18:04, 31 October 2019 (UTC)[reply]

Height of a child actor/actress

How could I work out what height a child actor/actress was from age 5 to 20 years old? For example, what height was Jake Lloyd (who is now 30 years old and his height is 1.65 m) when he played young Anakin Skywalker in Star Wars: The Phantom Menace at age 8? 86.128.246.20 (talk) 21:48, 31 October 2019 (UTC)[reply]

It sounds like you are looking for a formula. That wouldn't work well because everybody grows at different rates, including growth spurts at variable times. Better to try to estimate it by pics of him at the time next to objects of known height, like adult actors. SinisterLefty (talk) 22:04, 31 October 2019 (UTC)[reply]

Assuming the heights we "know" for them are correct. Adding an inch to an actor's published height is not exactly uncommon. --Khajidha (talk) 14:28, 1 November 2019 (UTC)[reply]

Growth-height charts are common. Human height is correlated to age and falls very closely into a natural distribution. So, you can estimate a person's height with age within a standard deviation. Some people are outliers. For example, I stopped growing at age 13, but when I was 13, I was by far taller than anyone else my age that I knew. So, if you attempted to place my adult height on the growth chart, you would underestimate my height at 13 because you would assume that I grew after that age. 135.84.167.41 (talk) 16:12, 1 November 2019 (UTC)[reply]

Note that those charts show averages, but child actors are often chosen because they are short for their age, and thus they can have a more experienced actor play a younger role. SinisterLefty (talk) 16:42, 1 November 2019 (UTC)[reply]

November 1

Ethanol fermentation

A friend and I were joking around about different generic names for all alcoholic beverages. Two of our favorites were "Liquid Stupid" and "Yeast Poop". This led to an interesting question. Are all alcoholic beverages based upon yeast fermentation? Our Ethanol fermentation page says

" All ethanol contained in alcoholic beverages (including ethanol produced by carbonic maceration) is produced by means of fermentation induced by yeast.^{[citation needed]} "

The answer to this refdesk question might allow us to replace that citation needed with a citation or possibly edit it and add a citation if it turns out to be incorrect.

Our Zymomonas mobilis article says

" Zymomonas mobilis is a Gram negative, facultative anaerobic, non-sporulating, polarly-flagellated, rod-shaped bacterium. It is the only species found in the genus Zymomonas. It has notable bioethanol-producing capabilities, which surpass yeast in some aspects. It was originally isolated from alcoholic beverages like the African palm wine, the Mexican pulque, and also as a contaminant of cider and beer (cider sickness and beer spoilage) in European countries. "

Our Pulque page says

" Unlike beer, the fermenting agent present in pulque is a bacterium of the species Zymomonas mobilis (syn. Thermobacterium mobile ^[1]) rather than yeast. "

References

^ "Zymomonas mobilis". www.uniprot.org.

Only one problem. The citation on the pulque page doesn't seem to support the claim, and the claim on the Z. mobilis page is uncited.

Finally, our Palm wine page says

" Palm sap begins fermenting immediately after collection, due to natural yeasts in the air (often spurred by residual yeast left in the collecting container). "

and makes no mention of Z. mobilis.

So, are all alcoholic beverages made from "Yeast poop" (yeast fermentation) or not? What do the sources say? --Guy Macon (talk) 08:35, 1 November 2019 (UTC)[reply]

It is possible to produce an alchohol molecule through a chemical process. Alcoholic beverages are not created that way because it is much cheaper and easier to let yeast do the work. There are processes named things like "fermentation without yeast." That doesn't mean that yeast isn't used. It means that yeast is not added. The yeast that is naturally found in the system is used instead. 135.84.167.41 (talk) 16:09, 1 November 2019 (UTC)[reply]

Z. mobilis is one of the fermenting agents, according to [3]. Also a couple of lactobacilli, also the yeast Saccharomyces cerevisiae. --jpgordon^{𝄢𝄆 𝄐𝄇} 18:07, 1 November 2019 (UTC)[reply]

All of our alcoholic beverages (AFAIK) are made from "yeast poop". Except for one - Vladivar Vodka, from Varrington. In a manner rather reminiscent of non-brewed condiment, this was made from an industrial ethanol byproduct stream (Varrington was the centre of the UK chemical industry), bottled up for human consumption. OTOH, post-Weizmann, nearly the whole UK chemical industry was based on yeast (or at least, bacterial) poop anyway. Andy Dingley (talk) 23:30, 1 November 2019 (UTC)[reply]

PC voting system in Fla (2000)

Hi, even if this system was widespread in only 24 out of 67 counties, is it possible that the punched card system was the most widespread method of voting at the state level, as far as the electors in general are concerned? I say this, because these machines were the ststemi also used in the most populous counties, and this affects. Thank you. I don't need figures, it's not necessary. — Preceding unsigned comment added by 93.41.100.198 (talk) 15:02, 1 November 2019 (UTC)[reply]

If you already have the figures, then what's your question? ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:06, 1 November 2019 (UTC)[reply]

I would have found the source to be reliable, I need a confirmation. If you go to this link on page 633 (9/74) there is a table with the voting systems and the numbers expressed with the systems themselves. Out of 6 million votes in total, 3.7 million preferences were expressed with punched card systems. So I assume that the majority of state voters in that year used and voiced their votes with the Votomatic machines, the sucittate ones. It is the first table. https://scholarship.law.berkeley.edu/cgi/viewcontent.cgi?article=2525&context=facpubs

November 2

information sign in japanese in a californian prison near the condom machine

Hello there, I saw this video https://youtube.com/MRmwtgcm_p0 and I just cant believe what I saw. Are in the prisons of california so many japanese people locked that there is this need for such signs in japanese? If yes, how does it come? Japanese and the japanese people aren't for me really "known" as "criminals". And if this sign is necessary it has to mean, japanese is spoken by many many prisoners inside this prison. And of course, these presumed japanese prisoners want to have these condoms (thats reason 2 why I cant believe why that sign exist). We in Germany do have some information signs in arabic, kurdish and some african languages which tell you for example "do not poop in the shower" (example) because there is the necessary for it, otherwise we would not teach them any "european culture". Are japanese really criminals, are really so many japanese people living in california that there is the necessary for it? I was guessing the most japanese people do live in Hawaii and if they live there, they aren't really many in the prisons. Can you help me to understand why there is this necessary for the sign in japanese? I have a culture-shock, I never saw japanese people as criminals --46.167.62.33 (talk) 02:55, 2 November 2019 (UTC)[reply]

[1] "Zymomonas mobilis". www.uniprot.org.

[1]