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April 17

Wood in motor cars

Which was the last production motor car that used wood in the main structure or frame of the vehicle, i.e. not just as a decorative interior feature? Thanks. 86.181.187.25 (talk) 19:29, 17 April 2022 (UTC)[reply]

The Morgan Motor Company still does this. Bazza (talk) 19:34, 17 April 2022 (UTC)[reply]

Surely, it's less safe than metal? 86.181.187.25 (talk) 19:37, 17 April 2022 (UTC)[reply]

Morgan claim it's safer. DuncanHill (talk) 19:57, 17 April 2022 (UTC)[reply]

I wonder what's worse: To be impaled by a piece of wood or a piece of metal? --←Baseball Bugs ^{What's up, Doc?} carrots→ 06:07, 18 April 2022 (UTC)[reply]

Are you a vampire? Then wood is worse unless the metal is silver, particularly when coated in garlic. --Lambiam 07:06, 18 April 2022 (UTC)[reply]

So it's the upper body structure, covered in aluminium sheeting, rather than the chassis. "Morgan’s research shows that the wooden frame makes its cars safer than conventional steel frames on impact tests." Doesn't the UK Government have to do independent tests? Thanks. 86.181.187.25 (talk) 07:40, 18 April 2022 (UTC)[reply]

Neither the USA or the UK governments routinely do crash tests. Instead the manufacturer gets their cars tested at a crash test facility. I think in theory you can get a car into production using your own test lab. Greglocock (talk) 09:47, 18 April 2022 (UTC)[reply]

You do have to watch where the wood is fitted. Martinevans123 (talk) 09:30, 18 April 2022 (UTC)[reply]

Certification in the UK is by the Vehicle Certification Agency. Actual testing was by the Road Research Laboratory (RRL), which was privatised in 1996 as the Transport Research Laboratory (now TRL Limited). TRL was instumental in setting up Euro NCAP in the EU. Testing by these bodies seems to be voluntary, but not having a rating by them isn't a good selling point. Alansplodge (talk) 15:47, 18 April 2022 (UTC)[reply]

Morgan isn't listed on the Euro NCAP site. Perhaps people who buy Morgans aren't that fussed about modern standards? -- Verbarson ^talk_edits 20:57, 18 April 2022 (UTC)[reply]

"Of course, there is only so much safety tech that the Plus 4 offers -- there are no air bags, for instance -- and crumple zones are just bodywork that will crumple in a crash. In this case it was fortunately enough to prevent a far worse outcome".

Morgan Plus 4 driver miraculously survives this high-speed rear-end crash. Alansplodge (talk) 13:13, 19 April 2022 (UTC)[reply]

(EC) Our article suggest at least in 2005, they had limited or no airbags, so I would expect they do fairly poorly in a number of modern tests whatever the alleged benefits of the wooden frame. Nil Einne (talk) 13:18, 19 April 2022 (UTC)[reply]

Marcos made cars with wooden chassis but they appear to have swapped to steel in 1969.[[1]] --Ykraps (talk) 09:18, 20 April 2022 (UTC)[reply]

April 19

Short cutoffs

When driving a steam train at high speed, how can you tell if you've set the cutoff too short? I do know that the effect of this, in physical terms, is a "checking action" where the steam cannot fully exhaust to the blastpipe and creates a pressure cushion in the cylinders -- but my question is, how does this manifest itself in terms of sound and/or feel (sharper exhaust blasts, increased shaking, etc.)? And is the sound/feel in this case different with Stephenson valve gear than with Walschaerts? 2601:646:8A81:6070:8D25:F11A:29AC:2783 (talk) 00:05, 19 April 2022 (UTC)[reply]

Surely a longer cutoff would supply too much steam to the cylinders; a short cutoff would supply less? See Cutoff (steam engine). (Would that I had the experience to actually answer the question!) -- Verbarson ^talk_edits 10:04, 19 April 2022 (UTC)[reply]

Not my field, but I found Explaining 'Cut Off' on a rail enthusiasts' blog, which may help. Alansplodge (talk) 13:02, 19 April 2022 (UTC)[reply]

Just read it, but it only explains what a cutoff is (which I already know), and the (rather obvious) effects of having it set too long while cruising at speed -- wasted steam and coal (and reduced performance due to lack of steam available), fire-throwing with consequent emissions of excessive smoke (harmful to the environment, could be dangerous in tunnels) and possibly sparks (fire hazard), and with a lever reverse also possible injury to the engineer if he tries to adjust it and it flies open uncontrollably under steam pressure -- but what it does not cover is what happens if the cutoff is set too short while cruising under power. 2601:646:8A81:6070:2152:CE20:4F73:F64E (talk) 09:14, 20 April 2022 (UTC)[reply]

@User:Verbarson: True, but a short cutoff also gives the steam less time to exit the cylinder to the blastpipe during the exhaust phase -- this is why setting it too short can lead to a checking action which reduces speed. 2601:646:8A81:6070:2152:CE20:4F73:F64E (talk) 09:17, 20 April 2022 (UTC)[reply]

April 20

What's the proper umbrella term for ultimate carbon bats, swords, elevator cables, vehicle bodies, illegal golf clubs, armor vests, I-beams and similar?

I could say ultimatium or unobtainium but what's meant isn't obvious. If I said i.e. carbon tool, carbon tennis racket or carbon bike that sounds like carbon fiber composite which is not nearly weightless like a real nearly unimprovable human-powered bike would be. What about calling them carbon nanotech objects, could that be unclear as to whether it includes non-structural nanotech such as transistors or something? Sagittarian Milky Way (talk) 00:59, 20 April 2022 (UTC)[reply]

We have Category:Nanomaterials. Perhaps "carbon nanomaterial objects"? Card Zero (talk) 07:46, 20 April 2022 (UTC)[reply]

Would carbon-fiber-reinforced polymers cover what you have in mind, Sagittarian Milky Way? Mike Turnbull (talk) 09:42, 21 April 2022 (UTC)[reply]

No, those already exist and are far heavier or weaker than anything near the ultimate macroscopic strength limits of atomic bonds. What's the correct term I can use for atomically perfect 3D printed (macroscopic) X's if I don't know if the best X's are nanotube X's or graphene X's or buckyball-nanotube-graphene fractal foam composite magic X's? Will the best baseball bats be nanotube or graphene foam or a single giant multi-wall nanotube or a spiral of one sheet of graphene or what? I have no idea but I shouldn't have to know to the general category right? I don't know if it'll ever be feasible to 3D print so many atoms into an atomic-level flawless lattice but that might be the way (to make the strongest or thinnest possible stick or sheet or string or whatever). Sagittarian Milky Way (talk) 01:29, 22 April 2022 (UTC)[reply]

Very likely there is no "correct term" for such a class of hypothetical things because nobody has yet had any need for it. Feel free to invent one – it might even catch on. {The poster formerly known as 87.81.230.195} 90.197.101.71 (talk) 04:01, 22 April 2022 (UTC)[reply]

Railway construction

Generally in a new railway construction project like the UK’s High speed 2, are the stations the most complex part in the early civil engineering stages of construction? Compared to say bridges, tunnels, earthworks, retaining walls, boxes etc? Clover345 (talk) 22:12, 20 April 2022 (UTC)[reply]

Train station design is largely the province of architecture. In terms of civil engineering, there is nothing much special or demanding about station design, but remodelling existing stations to meet the demands of modern railways can be a challenge – the easiest may be to build a new station. It is difficult to say something in general about the complexity of new railway construction projects, since so much depends on the local circumstances. The civil engineering complexity of HS2 is incomparable to that of HS1. Also, where do the early civil engineering stages of construction start (do they involve the detailed selection of the route?) and end? --Lambiam 07:29, 21 April 2022 (UTC)[reply]

I would think building bridges and tunnels is much more difficult than building stations. There are many known delays with those types of projects due to unforeseen problems with the terrain, even after exhaustive planning and environmental studies. The risks are also greater. A bridge or tunnel fiasco could derail an entire project, especially if there are no alternatives to bypass that location. They also tend to happen in more remote places, which makes the logistics more difficult compared with stations, which are usually placed in more populated areas with existing infrastructure. GeorgiaDC (talk) 19:04, 21 April 2022 (UTC)[reply]

It also should be noted that there's a distinction between the station and the platform, the former is really superfluous to the operation of the railway. A station is really just a place to wait to board the train; a "station" could be a simple as a bench: see for example Appalachian Trail station. I used to take Amtrak from Newark station in the 1990s, at the time there was no indoor station, just a place to wait to get on the train with a few benches, and a large commuter parking lot (the original station building was there, but it was boarded up IIRC) You couldn't even buy tickets there, you had to purchase them from the conductor once you got on the train. It looks like it has since been upgraded, FWIW. Yes, really complex modern train stations resemble airports, but they aren't any different from, say, a shopping mall with a place to access the platforms. --Jayron 32 19:34, 21 April 2022 (UTC)[reply]

In terms of the engineering of the permanent way Lambiam, GeorgiaDC and Jayron have pretty well covered it. Where a station (as a against a simple platform) does increase the complexity is in the pointwork, crossings and signalling to direct trains to the appropriate platforms. Then add in the main buildings with its associated supplies (water, electricity, in the past gas), drainage (rainwater, foul water), vehicular access and parking. There's bridges (either over or under the line) with associated lifts, escalators lighting etc. All supplies crossing under the tracks need to be insulated against ground movement due to trains passing over. HS2 has overhead electrification so each separate road or siding needs cateneries. None of this is as unpredictable as tunneling or as complex as significant viaducts but it's still not trivial. Martin of Sheffield (talk) 20:19, 21 April 2022 (UTC)[reply]

For HS2, the stations seem just as complicated if not more complicated than the tunnelling and other civils. Most of the station contracts are worth over £1 billion which is the same value as most of the civils contracts covering a much larger area. — Preceding unsigned comment added by Clover345 (talk • contribs) 00:50, 22 April 2022 (UTC)[reply]

But is this complexity due to civil engineering requirements, as specified in the question, or does it stem from architectural requirements? --Lambiam 14:26, 22 April 2022 (UTC)[reply]

Would you happen to have any reference or related information on these contracts for more details and comparison? GeorgiaDC (talk) 18:50, 22 April 2022 (UTC)[reply]

If you want to see this in action a new entrance, ticket office and footbridge are nearing completion at Hackney Central railway station. If the station becomes part of the Chelsea to Hackney Line the engineering will be very different. 2A00:23A8:4306:5D01:B995:7B23:A571:2AA9 (talk) 11:20, 23 April 2022 (UTC)[reply]

April 21

Do all flowers need sunlight to blossom?

Having located the linked article my wife and I have had a heated debate concerning flowers. We would like the following question answered.

Do all flowers require sunlight in order to bloom? Clearly not all flowers need sunlight to develop, and not all plants need sunlight in order to survive. Our question relates specifically to the opening and blooming of flowers.

https://news.mongabay.com/2019/08/new-orchid-species-from-japan-lives-on-dark-forest-floor-never-blooms/amp/

Thank you — Preceding unsigned comment added by 2A00:23C6:6888:C600:28F4:D64D:6F71:62B8 (talk) 20:57, 21 April 2022 (UTC)[reply]

There are a lot of plants that bloom at night (see Category:Night-blooming plants) I don't know what triggers them to bloom ("when it's dark" vs "when it becomes no-longer-light"). So I'm not sure if that does or doesn't qualify for your interest. DMacks (talk) 21:50, 21 April 2022 (UTC)[reply]

BTW, all plants need some sunlight, even if not directly - see photosynthesis. Alansplodge (talk) 22:43, 21 April 2022 (UTC)[reply]

Tell it to Gastrodia kuroshimensis. (That one doesn't bloom, which is the key to the question.) --jpgordon^{𝄢𝄆𝄐𝄇} 23:04, 21 April 2022 (UTC)[reply]

This being the Science Desk and all, I think some precision is required here. Is the question asking about direct sunshine on the flowers being required for them to bloom, or just daylight? If it's the former, the answer is obviously no. Many flowering plants in deep mountain valleys never experience direct sunlight. HiLo48 (talk) 00:07, 22 April 2022 (UTC)[reply]

OP here, different computer. Without being in a cave it would be well nigh impossible to have no sunlight. The question relates to the plant receiving direct sunlight in order for the flower to bloom. Deep valleys may have flowers but they are not dark to the point of near 0 sunlight such as experienced in deep jungle floors where the flower in question grows. Thanks — Preceding unsigned comment added by 62.252.54.42 (talk) 11:04, 22 April 2022 (UTC)[reply]

Flowering room plants often do not need (and do not receive) direct sunlight. For a few examples, see here. --Lambiam 14:21, 22 April 2022 (UTC)[reply]

OP again. Thank you, and if the flowers do not receive any sunlight such as those that exist in caves...those never bloom because they never receive sunlight? Is that accurate without deviation and exception? Thanks — Preceding unsigned comment added by 62.252.54.42 (talk) 15:24, 22 April 2022 (UTC)[reply]

There are parasitic plants that don't do their own photosynthesis, and only emerge above ground or out of the trunk of the host plant to flower and set seed. The fact that the sun shines on them at that point is probably of only indirect interest to them. Abductive (reasoning) 07:37, 23 April 2022 (UTC)[reply]

It is disappointing that the original questioner seems to have a better grasp of the issue than most of those who have responded! One study has shown that in the parasitic plant Dodder the cue to initiate flowering comes from the FT protein generated by the host and used by the host plant to initiate its own flowering. The trigger for flowering in the host plant is in most cases photoperiod, so still you need to have light in the system, although not directly illuminating the Dodder plant itself. The same article points out that "very little is known about how flowering of parasitic plants is regulated". Jmchutchinson (talk) 09:16, 23 April 2022 (UTC)[reply]

That's what I alluded to by indirect interest. Even holoparasites have to engage with the pollinators and seed dispersers, and know what season it is. An example is beechdrops (interesting that both it and dodders have an always-plural name.) Dodders is an aboveground plant and only hemiparasitic. Abductive (reasoning) 16:19, 23 April 2022 (UTC)[reply]

Dodder, singular. Bazza (talk) 09:05, 24 April 2022 (UTC)[reply]

In any case, no evidence has been presented that the light plants may need for flowers to open and bloom has to be, specifically, sunlight. Here Corydalis lutea is reported to be a blooming perennial that thrives even in dense shade. --Lambiam 10:01, 23 April 2022 (UTC)[reply]

April 23

Physics

How I can provide that after collision and before collision of the car when it was in the road and it have a passenger,,?? — Preceding unsigned comment added by 41.222.180.178 (talk) 10:23, 23 April 2022 (UTC)[reply]

Start at traffic collision. 2A00:23A8:4306:5D01:B995:7B23:A571:2AA9 (talk) 11:16, 23 April 2022 (UTC)[reply]

The question is not fully clear. Do you want to understand the physics aspects of a car collision (as in inelastic collision)? --Lambiam 16:21, 23 April 2022 (UTC)[reply]

Computed tomography scan and slices

I would kindly ask for information, I know that in spiral CTs the data of "slice thickness" and the distance between two consecutive slices "Spacing Between Slices" are important. However, I would like to understand if there is a gap in the CT that I performed between two slices. I mean if there is a "dark spot" not represented between two consecutive slices. I have found the following data of two consecutive slices of a ct, and I would like to ask if it was possible to calculate a possible dark spot, that is, if there is a gap not represented by images between two consecutive slices.

DATA: Spiral pitch factor. value: 0.65

slice thickness. value: 1.0

Gantry tilt: +8.5 — Preceding unsigned comment added by 37.161.25.209 (talk) 08:18, 24 April 2022 (UTC)[reply]

FIRST SLICE:

image position patient. value: -130.2261\-165.1111\1790.323

image orientation patient. value: 1.00000\0.00000\0.00000\0.00000\0.98902\0.14781

SECOND SLICE:

image position patient. value: -130.2261\-165.1111\1791.124

image orientation patient. value: 1.00000\0.00000\0.00000\0.00000\0.98902\0.14781

In practice the only value that changes is the third component of image position patient Δ=0.800 about.

I'm asking to myself if slices all overlap, that is, if there are not dead acquisition spaces or if there are, according to these data. It is absolutely not a medical question, I'm just a curious engineer about the data of the exam I took.

Thanks :) --37.160.236.73 (talk) 16:33, 23 April 2022 (UTC)[reply]

I'm not sure, but I think the beam should be minimally overlapped during the scan (to reduce patient exposure to X-rays), then the computer processes the slices into a dataset that can be rotated into whatever 3D view the technician or physician desires. Maybe one can set the settings such that slices don't overlap and leave gaps. Abductive (reasoning) 20:01, 23 April 2022 (UTC)[reply]
My understanding is that a pitch factor < 1 means that the distance travelled by the scanned body during one rotation by the scanned body is less than the beam width, so there is no gap. In fact, there is some overlap, which helps in stitching the slices together to a continuous sinogram, also when the patient is not absolutely still. What is as relevant from a medical perspective as the absence of significant gaps, is the resolution. If I understand the basic mathematical principles of CT correctly, only detail that is significantly wider than the beam width will be visible in the resulting image, which is also what one would naively expect. --Lambiam 20:23, 23 April 2022 (UTC)[reply]
Just to confirm, pitch < 1.0 means overlap.[2] DMacks (talk) 20:29, 23 April 2022 (UTC)[reply]

Thanks for answers:D! It was also my idea. Buy i read (about tilt gantry and and normal to the slice):

1- http://xrayphysics.com/ctsim.html

2- https://groups.google.com/g/comp.protocols.dicom/c/Qw2nWtElu2c

3- https://groups.google.com/g/comp.protocols.dicom/c/lEp7NmiHIT0 that instilled doubts to me. In 5° message looks like that to calculate any spacing between two slices you have to project the reference system of patient onto the machine reference system (directory cosines). --37.163.149.54 (talk) 21:52, 23 April 2022 (UTC)[reply]

Fuel source for electricity production in the US

The war in Ukraine has raised concerns regarding Europe's dependence on Russian gas/oil. But here in the US, where we gobble power.... The New Yorker states "Electrifying your home one machine at a time is today’s Victory Garden", and referred to The Hill, which recommends "Electrifying the machines we use to heat our air and water, cook our food, dry our clothes, and take our kids to school..." So, how is the electricity produced? In the US, hydroelectric is not universally available?? Same for nuclear, wind power, solar? That leaves coal, natural gas, etc. I live in a rural area, and have used "propane" (stored in a 500 gal tank) for heat, hot water & cooking, for the past 36 yrs.

My question: Is it more effective to use fossil fuels (at a power plant) to produce electricity for the end user, versus just using natural gas or "Propane"/LPG as the end user? Thanks, Tribe of Tiger ^{Let's Purrfect!} 21:41, 23 April 2022 (UTC)[reply]

The overall efficiency of "heat at the home" from various fuel-sources and routes of transmission is a popular topic. A furnace (central heating), per our article, "can be up to 98% efficient...with a typical gas furnace being about 80% efficient." That's about the most direct "burn fuel-->heat air" route. A combined cycle power plant is up to 64% for electrical generation, and then there would be further losses when that electricity is converted to heat at the home. However, even the poorest heat pump has a coefficient of performance higher than two, so when that device is used for heating, it more than makes up for the lower efficiency of the electrical generation. This is all just back-of-the-envelope...I'm sure it's been analyzed in more detail in many published references. DMacks (talk) 23:05, 23 April 2022 (UTC)[reply]

The question does not take into account the likelihood of commercial electricity generation itself becoming less and less dependent on fossil fuels in the future.

In my own country, the UK, non-fossil fuel sources (other than Nuclear power) were a negligible component of National Grid electicity supply well into my adult lifetime; as I type right right now (in the middle of the night), fossil fuels are supplying only 16.62% of the total demand, with the rest coming from Nuclear and Wind power, renewable Biomass (using purpose-grown trees and sawmill waste), plus 0.62% of Hydroelectricity. During the day Solar power makes significant contributions (averaging around 20% at noon over the past week), and stored Hydroelectic power is deployed around dawn and dusk to smooth out transitions. (See this handy site.) The trajectory is to continue reducing routine fossil-fuel use to near-zero over the coming decades.

Assuming the USA chooses to follow the same trajectory, supplied electricity there should also become increasingly non-fossil derived, so domestic electrical appliances will become increasingly less dependent on fossil fuel without the homeowner even having to do anything further to bring this about. Moreover, as the technology improves and economies of scale ramp up, increasingly efficient home installations of solar power panels and heat exchangers (as technology advances) can also be deployed where possible to reduce dependence on external supply and even yield income by selling power to the grid.

Note that "efficiency" of supply won't matter a damn if the place one lives becomes uninhabitable due to the effects of Global warming largely caused by fossil-fuel use. I personally expect this to happen in the South Western states of the USA around 2050 unless drastic measures are implemented, but I'm not an expert. {The poster formerly known as 87.81.230.195} 90.197.101.71 (talk) 02:13, 24 April 2022 (UTC)[reply]

You might want to check the EIA's prediction of fuel source for electricity 2022-2050. Bit of a drop in coal, more gas. https://www.eia.gov/outlooks/aeo/pdf/AEO2022_ChartLibrary_Electricity.pdf p5 Greglocock (talk) 07:38, 24 April 2022 (UTC)[reply]

Our article say that the US uses about 40% natural gas, 20% coal, 20% nuclear and 20% renewables for its production of electricity, so that's about 60% fossil fuels and the coal is worse than the propane you burn at home. The efficiency of fossil fuel power stations is around 50%. The most modern units reach around 60%, some claim a bit more as they say they found some use for their waste heat, but the oldest units still in use are around 40%. When you want high temperature heat (like in cooking), this electricity can be turned into heat only by resistors (induction cooking also uses a resistor, the cooking pot itself), so the efficiency is 50%. A gas stove has limited efficiency too, assuming the burners aren't too large around 60% or so, so for cooking, electrifying right now may not be much of an improvement, but gets better as the proportion of fossil fuels in electricity generation falls.

For low temperature heat, you can use heat pumps. A properly functioning heat pump has a coefficient of performance more than high enough to compensate for the losses in a fossil fuel power station. Unfortunately, heat pumps don't always function properly. In temperatures close to freezing and moist air (which, depending on your climate, may be when you need most of your heating), many types (in particular the more affordable ones) can get clogged with ice, turning them into resistive heaters, which is worse than heating your home with gas directly.

So, yes, electrifying your home helps, but it's not magic. Try to cut back on energy use, get solar panels if you haven't already and tune you power consumption to match generation of the solar panels during the day. And I've got no kids, but when I was one myself, I went to school by bike. Fully muscle powered, it doesn't get cleaner than that. PiusImpavidus (talk) 09:29, 24 April 2022 (UTC)[reply]

April 24

handheld scale

I was at an outdoor Chinese market and the lady there weighed vegetables on a handheld scale that looked pretty cool, primitive and yet totally functional. I didn't manage to look at it closely since she didn't seem to like it when I tried. I am wondering what it worked. I think it may have been a steelyard balance but according to the article, those work by having the weighing pan at one end, the pivot in a fixed location some distance from the end, and a sliding weight that you move on the arm to make the arm horizontal.

I am wondering if there is a known variant of this, where the weighing pan is fixed at one end of the arm, the counterweight is fixed at the other end, and you move the pivot until the arm is horizontal. The pivot would be a knife-like edge and the arm would have a bunch of marked notches for different weights. So you'd put the knife edge under whichever slot brought the whole thing into balance.

If that's not a common design, is there a reason it wouldn't work? I'm thinking of making something like it as a very portable weighing scale. Materials would be a wooden chopstick as arm, pocket knife blade for pivot, and water bottle or similar for counterweight. Thanks. 2601:648:8202:350:0:0:0:4671 (talk) 07:50, 24 April 2022 (UTC)[reply]

Well it would work, but (if I understand correctly) to adjust it you would need lift much of the mechanism plus the load, rather than simply slide a small mass along the bar, so it would be a bit fiddly. And it would only be as accurate as the distance between the notches.--Shantavira|^{feed me} 08:21, 24 April 2022 (UTC)[reply]

A simpler design is the traditional apothecary’s balance, and our weighing scale article also has some details. Alansplodge (talk) 09:53, 24 April 2022 (UTC)[reply]

Thanks both. The apothecary balance is a double pan balance that needs a set of weights, so it doesn't seem practical here. I'm trying to have something very lightweight and simple. Lifting the balance with the load isn't likely to be a problem since it would only be for weighing light stuff. I gave the example of a water bottle (500g of 1kg) as counterweight but in practice the loads and counterweights would be a lot lighter, like a few ounces. 2601:648:8202:350:0:0:0:4671 (talk) 10:55, 24 April 2022 (UTC)[reply]