For Questions That Don't Merit Their Own Thread

[DDE]

30 minutes ago, magnemoe said:

Think this is the main reason, looking at ships it looks like number of funnels went down while the height stayed the same. Its ways to get around an small funnel like fans or using the air speed to generate draft after all and it was better to have an larger boiler for more power

Stability is also a much bigger concern for ships. Topweight bad.

[FleshJeb]

Not apropos of this particular thread: Is it possible for us to be less reductive and hyperbolic when discussing serious scientific matters? Or is poop-flinging more entertaining than having serious, good-faith exchanges and learning things?

[razark]

1 hour ago, FleshJeb said:

Not apropos of this particular thread: Is it possible for us to be less reductive and hyperbolic when discussing serious scientific matters? Or is poop-flinging more entertaining than having serious, good-faith exchanges and learning things?

While I understand what you're saying, I will put forward that (even if this is not the standard sort) this is, above all else, a video game forum.

[SunlitZelkova]

3 hours ago, FleshJeb said:

Not apropos of this particular thread: Is it possible for us to be less reductive and hyperbolic when discussing serious scientific matters? Or is poop-flinging more entertaining than having serious, good-faith exchanges and learning things?

A couple reasons this happens-

1. "Children" (that is, mentally) getting emotional and not taking things seriously

2. Human nature. It is instinct to turn to conflict and fighting over constructive discussion. Sadly, human intellect has not been able to get around the fact that "thing opposing you [in some manner]" does not actually threaten you.

I personally think it is inevitable.

[kerbiloid]

(Silently compares this calm and quiet place to any Russian tech forum...)

Spoiler

"American forum. You ask a question, you get the answer.

Israeli forum. You ask a question, you get a question.

Russian forum.  You ask a question, you read all day long, what a silly jerk you are."

(c) internet

 

[kerbiloid]

Were those extinct fuzzy toys enough intellectual to be domesticated like the modern ones?

Or they were too primitive and stupid for that like reptiles, and the modern cats&dogs&horses are the first species generation enough clever?

Do we know anything about the primordial species intellectual abilities compared to the modern ones?

Spoiler

 

P.S.
Can a koala be trained?

Edited December 24, 2021 by kerbiloid

[Hyperspace Industries]

1 hour ago, kerbiloid said:

Can a koala be trained?

Why would you need to do that? A koala is a slow and peaceful herbivore (don't cite me on that, I'm an armchair rocket enthusiast, not a biologist), it won't harm you and it flatly refuses to attempt to harm anything but plants. Anyway I doubt it would be any good in a hunt.

 

 

 

If I may ask a question, there are some old soviet spysat nuclear reactors in a disposal orbit (uranium and reentry aren't the best of combinations) around earth. Could these be refueled and started up again to power bases and ships. (It would be handy for a moon base or (in the case of an idea I've had for sci fi) a pirate ship.)

[kerbiloid]

37 minutes ago, Hyperspace Industries said:

Why would you need to do that?

No need. Just to understand the fork between the dumb-and-dumber and dogs-and-cats, and if there were previously species compatible to the latter intellectually.

37 minutes ago, Hyperspace Industries said:

A koala is a slow and peaceful herbivore

Afair, its deadly and bloodthirsty in their corporative battles, just too slow and dumb to attack anything faster.

37 minutes ago, Hyperspace Industries said:

Could these be refueled and started up again to power bases and ships.

They are small and expendable, so currently useless.

https://en.wikipedia.org/wiki/US-A

Edited December 24, 2021 by kerbiloid

[DDE]

1 hour ago, Hyperspace Industries said:

If I may ask a question, there are some old soviet spysat nuclear reactors in a disposal orbit (uranium and reentry aren't the best of combinations) around earth. Could these be refueled and started up again to power bases and ships. (It would be handy for a moon base or (in the case of an idea I've had for sci fi) a pirate ship.)

It's not reactors but reactor cores. Most of them would be hopelessly contaminated with neutron poisons, and therefore the fuel would need full reprocessing to recover the usable uranium.

[Hyperspace Industries]

I'm thinking of making a model rocket motor that uses the reaction of baking soda and vinegar and then pushes the expanding foam through a nozzle to make at least a bit of thrust. I can't find the rate at which the foam expands anywhere on the internet (all I get is cork gun rockets) I'm looking for a rocket engine with not too much thrust (very low thrust actually) and constant exhaust instead of a cork gun rocket's single burst. Also it can't use combustion because that is literally illegal here.

Are there any such reasonably easy to build model rocket engines.

Also: what rate does baking soda and vinegar expand at, and could my model rocket idea work.

[kerbiloid]

2 hours ago, Hyperspace Industries said:

I'm thinking of making a model rocket motor that uses the reaction of baking soda and vinegar and then pushes the expanding foam through a nozzle to make at least a bit of thrust

Have you first tried the soap rocket for safety?

Spoiler

1. Cut a rocket shape from thick paper.

2. Cut a triangle of nozzle in its aft, and a circle of combustion chamber on top of the triangle.

3. Put it onto water.

4. Drop a droplet of soap solution or of shampoo into the chamber.

5. The shampoo/soap expands from the chamber through the nozzle due to the difference of surface tension, and pushes the rocket in opposite direction.

https://www.chemedx.org/blog/soap-boat-20

 

But don't forget to use glasses to protect your eyes

Spoiler

from the shampoo.

Edited December 24, 2021 by kerbiloid

[SunlitZelkova]

6 hours ago, kerbiloid said:

Were those extinct fuzzy toys enough intellectual to be domesticated like the modern ones?

As far as "animal intellect" goes, there is nothing different from present species.

Obviously some species that were exclusive to an era (like large mammals of the Pleistocene) might have less cognitive capability due to their brains being small in proportion to their bodies, but in general, animal cognitive capability is the same as it has been since animals were a thing.

6 hours ago, kerbiloid said:

Or they were too primitive and stupid for that like reptiles, and the modern cats&dogs&horses are the first species generation enough clever?

The ancestors of modern domesticated animals weren't "more evolved", they just happened to be able to do it.

Just as some species don't appear to have any potential for domestication presently, during the Permian, some animals might have had 100% (successful) domestication potential, while some were impossible.

6 hours ago, kerbiloid said:

Do we know anything about the primordial species intellectual abilities compared to the modern ones?

This answer depends on the definition of "intellectual abilities" you are using for the question.

In general however, animal cognitive capability has been just as effective as it always has been (since animals became a thing).

It should be noted this probably can't be answered in a black-and-white manner. Giant beavers (Castoroides) had such cognitive capability that it survived against all sorts of predation for nearly 3 million years. You could say it had good "intellectual abilities". But then humans came along and it probably got hunted in droves. Throw in other factors like climate change and associated changes in the environment, and they went extinct. You could then say it did not have good "intellectual abilities".

[JoeSchmuckatelli]

37 minutes ago, SunlitZelkova said:

In general however, animal cognitive capability has been just as effective as it always has been (since animals became a thing

Not sure I'm hearing the argument correctly. 

If you are saying 'that with a brain, cogitates' then yes I'll agree.  Anything with a brain has some measure of intelligence - even if we don't know how to measure it. 

If you are saying that ancient animals cogitated as well as modern... The fossil record does not bear that out. 

https://evolution-outreach.biomedcentral.com/articles/10.1007/s12052-009-0136-1/figures/2

 

[K^2]

3 hours ago, Hyperspace Industries said:

I'm thinking of making a model rocket motor that uses the reaction of baking soda and vinegar and then pushes the expanding foam through a nozzle to make at least a bit of thrust. I can't find the rate at which the foam expands anywhere on the internet (all I get is cork gun rockets) I'm looking for a rocket engine with not too much thrust (very low thrust actually) and constant exhaust instead of a cork gun rocket's single burst. Also it can't use combustion because that is literally illegal here.

Reaction rate is going to depend on a lot of factors. Concentration of vinegar, temperature, how dry the baking soda is, how finely it's powdered, how you are mixing the two... Your best bet is to conduct some experiments and see what you get. Simple way to measure reaction rate experimentally is to get a jar with lid, make hole in lid, attach tube/hose to it, and run it into an inverted graduated cylinder (or just use a measuring cup) filled with water. The top of that cylinder/cup (which is a at the bottom, since it's inverted) should be submerged in a larger container filled with water. Any gas generated will be trapped in the inverted cylinder/cup, and you can easily measure the changes.

Obviously, start with small volumes of vinegar/soda mixture and see how you results scale as you adjust ratios and quantity. Hopefully, you can get something you can extrapolate from.

Once you have the reaction rate, you can balance it against the nozzle flow. You don't need to worry about expansion. Best nozzle for low velocity flow is a clean, round hole. Thrust is pressure times nozzle opening area, but also, mass flow rate times velocity. If the nozzle is at the bottom, you can effectively just take density of water for an estimate, so knowing the rate at which gas is produced will give you the nozzle area you need for target pressure. For a 2L plastic bottle, I wouldn't go above 5atm. Maybe even a bit under. This will also tell you the thrust, which will tell you if the rocket can fly.

It's hard for me to say if you'll be able to get enough thrust. Under ideal circumstance, there's enough energy and you can get a high enough reaction rate in energy. So it's possible. But if you can't get a high enough reaction rate, you can cheat. Make the nozzle larger, but start with it plugged. Also, leave about a quarter empty for air at the top. That will allow pressure to build up and use that stored energy to help the rocket start going. At that point, you basically have a water rocket, but you're still getting your energy from the baking soda reaction.

[DDE]

Can maritime diesels and gas turbines use bunker oil? I'm seeing mixed signals, especially when it comes to, sigh, the procurement politics behind late Soviet Navy steamships.

Spoiler

 

Edited December 24, 2021 by DDE

[FleshJeb]

2 hours ago, DDE said:

Can maritime diesels and gas turbines use bunker oil? I'm seeing mixed signals, especially when it comes to, sigh, the procurement politics behind late Soviet Navy steamships.

Take a look at the F-76 listing: https://www.globalsecurity.org/military/systems/ship/systems/fuel-oil.htm

EDIT: Looks like there are a few grades of bunker oil. I'm actually not sure now if F-76 qualifies.

EDIT 2: The answer is yes for gas turbines:
https://www.wartsila.com/energy/learn-more/technical-comparisons/combustion-engine-vs-gas-turbine-fuel-flexibility
"Only about 400 GE gas turbines globally operate on crude, naphtha or heavy fuel oils."

Edited December 25, 2021 by FleshJeb

[ARS]

4 hours ago, DDE said:

Can maritime diesels and gas turbines use bunker oil? I'm seeing mixed signals, especially when it comes to, sigh, the procurement politics behind late Soviet Navy steamships

AFAIK, most Russian warships that doesn't use gas-turbine or nuclear propulsion used Mazut as fuel. In the west, this is commonly called "waste oil" and in petrochemical term, Mazut is much like the equivalent of Number 6 Oil (Bunker C), and is part of the products left over after gasoline and lighter components are evaporated from the crude oil. Mazut is considered as "dirty oil", you're supposed to process Mazut with FCC or RFCC process to eventually produce the final product: diesel fuel, although it can still be used as fuel by itself, primarily in large boilers or power generators, since it has a high energy value. The drawback is the thick black smoke it produces (like Admiral Kuznetsov's infamous trails of heavy black smoke)

[SunlitZelkova]

21 hours ago, JoeSchmuckatelli said:

Not sure I'm hearing the argument correctly. 

If you are saying 'that with a brain, cogitates' then yes I'll agree.  Anything with a brain has some measure of intelligence - even if we don't know how to measure it. 

If you are saying that ancient animals cogitated as well as modern... The fossil record does not bear that out. 

https://evolution-outreach.biomedcentral.com/articles/10.1007/s12052-009-0136-1/figures/2

 

As far as logicality sounds, your argument has merit, but the source you provided does not appear to support it.

It is just a graph of what horse evolution "was" according to the data we had in the 1920s. I see nothing to show that predecessors of the modern horse somehow had "less cognitive capability" than modern horses.

I went through the entire article that graph is part of, but it is mainly just going over how "all over the place" evolution of hoofed mammals actually is in regards to physical characteristics, as opposed to past beliefs in paleontology, and defends the concept of evolution against creationists.

If I missed something, please point it out of course, but I see no reason why Pliocene horse would be any less better at grazing and evading predators than Holocene horse 

[DDE]

8 hours ago, ARS said:

AFAIK, most Russian warships that doesn't use gas-turbine or nuclear propulsion used Mazut as fuel. In the west, this is commonly called "waste oil" and in petrochemical term, Mazut is much like the equivalent of Number 6 Oil (Bunker C), and is part of the products left over after gasoline and lighter components are evaporated from the crude oil. Mazut is considered as "dirty oil", you're supposed to process Mazut with FCC or RFCC process to eventually produce the final product: diesel fuel, although it can still be used as fuel by itself, primarily in large boilers or power generators, since it has a high energy value. The drawback is the thick black smoke it produces (like Admiral Kuznetsov's infamous trails of heavy black smoke)

Oh, I know that's the official story. But I was beginning to get dissonance between the claim of boilers being more omnivorous (which is why they have proponents in the Russian military blogosphere to this day), and the facts that (1) maritime turbines burn diesel fuel (or so it's said, see below for ruminations over terminology), and (2) the predominantly diesel-powered global merchant fleet mainly burns heavy fuel oils.

Because there was also the mundane explanation of the Soviets having an overloaded turbine factory and an underused boiler factory.

11 hours ago, FleshJeb said:

EDIT 2: The answer is yes for gas turbines:
https://www.wartsila.com/energy/learn-more/technical-comparisons/combustion-engine-vs-gas-turbine-fuel-flexibility
"Only about 400 GE gas turbines globally operate on crude, naphtha or heavy fuel oils."

From other sources (admittedly read at 2AM) it appeared that aviation, tank and maritime ("aeroderivative") turbines exist in somewhat of a parallel universe to clean-sheet power turbines.

11 hours ago, FleshJeb said:

Take a look at the F-76 listing: https://www.globalsecurity.org/military/systems/ship/systems/fuel-oil.htm

EDIT: Looks like there are a few grades of bunker oil. I'm actually not sure now if F-76 qualifies.

It would appear that "bunker oil", at the end of the day, can refer to anything liquid that's used to power a ship. Not terribly helpful when we're discussing Residual Fuel Oils (RFOs).

USN standardizes around F-76, a distillate fuel, and there are attempts to make it switch to JP-5: https://core.ac.uk/download/pdf/36701292.pdf

This wiki page makes a valorous attempt to sort out at least some of the mess: https://en.m.wikipedia.org/wiki/Fuel_oil Interestingly it attributes the Russian standard of Navy Mazut to US standards of Number 4/Bunker A and Number 5/Bunker B (again, crossreferencing with other sources, this is a very rough comparison - others claim Number 5 corresponds to Bunker C), which means the US military service counterpart of the Navy Mazut is the Navy Special Fuel Oil. A cross-reference with Russian sources on the GOSTs for Navy Mazuts F-5 and F-12 also match the general descriptions.

So, with the terminology trip mostly over, let's go back to two questions: what do the civvies burn, and what is NSFO usable for?

Going back to the JP-5 study linked above gives us the answer to the latter: starting 1967 the Navy phased out NSFO, which was its principle fuel for boilers. Before that, it had to carry separate fuel for any diesel generators onboard.

OK, but that was roughly the era when maritime diesels already began to take over, so how can they burn something that's similar to or even worse than NSFO if they couldn't back then?

The answer is that apparently you need the really big, low-speed maritime diesels to handle the muck: https://www.marquard-bahls.com/en/news-info/glossary/detail/term/marine-fuels-bunker-fuels.html

And the civvies are overwhelmingly burning the various heavy/residual oils rather than the F-76-like Marine GasOil, unless local environmental requirements are in effect. So that closes the issue with diesels.

As a last shot, let's look at a specific diesel.

The 2038 family of corvettes uses four 10D49 diesels, which are part of a family of mid-RPM engines used in ships and locomotives for half a century. They're a simple V16. Only compatible with diesel fuel. God forbid we examine the 112-cylinder engines on the Karakurts, then.

So, I guess we're looking at the problem of sheer scale with diesels. By the end I was able to get a straught answer from Wikipedia on marine diesels: "Large ships use extremely efficient, low-speed two-stroke diesel engines. They can reach efficiencies of up to 55%. Unlike most regular diesel engines, two-stroke watercraft engines use highly viscous fuel oil."

...except here comes Junkers Jumo 205, an aircraft engine burning heavy oil muck! So such engines can in fact be miniaturized and have a fair specific power!

Meanwhile, the LM2500 turbine is USN's onelove. GE has a fuel flexibility sheet for it: https://www.ge.com/content/dam/gepower-new/global/en_US/downloads/gas-new-site/products/gas-turbines/GEA34108_Aero_Fuel_Flexibility_Whitepaper_Final.pdf And on pages 9-10 is has a very amusing section on crudes and residuals that says "yes, but no": RFOs are unrestricted for vanadium content, and vanadium reliably destroys "aeroderivative" turbines (for some reason, GE chose to be specific).

Vanadium, after chlorine, is the chief microelement in oil. But perhaps there are country differences. So, which of the Russian oil despoits are annoyingly rich in vanadium? Uhm, all of them. http://www.ivtn.ru/2011/pdf/d11_10.pdf Basically, you don't want RFOs anywhere near a gas turbine, but mazut F-5 is probbaly particularly bad .

So, let's summarize: while I've sorted out the fuels, I'm still confused as to whether (1) two-stroke diesels are more difficult to miniaturize, or are too deficient at specific power for military use - contraindicated by attempts at their use in aviation - and (2) whether a combustion-powered geared turbine is competitive with a gas turbine and appreciably superior to a pure diesel powerplant.

[ARS]

1 hour ago, DDE said:

(1) two-stroke diesels are more difficult to miniaturize, or are too deficient at specific power for military use - contraindicated by attempts at their use in aviation

Probably because on aviation application, the stress on the engine itself is far less compared to being used for maritime application. Looking on Junkers Jumo 205 application history, it's mainly used on slow-moving aircraft (either bomber or patrol aircraft), and their speed is considered slow by today's standard. Pushing a fuselage through air is less demanding than pushing a hull through water (not to mention the air itself helps lifting and maneuvering the aircraft). IT COULD be miniaturized, but I think it would have shorter lifespan compared when being used as aircraft engine because of higher stress in maritime application, and as a result, more replacing/ repairing the engine, which is not economical on the long run

[JoeSchmuckatelli]

@SunlitZelkova @StrandedonEarth @sevenperforce

Thanks for the info / advice on telescopes! 

We saw 3 of the moons of Jupiter and Saturn's rings tonight (despite being in a city).  Kid-girl is stoked! 

I ended up getting a good-cheap telescope (all things considered).  Got a Zhumell 100mm tabletop reflector.  Perfect size for her to carry around and not terribly expensive. 

Pleiades are barely visible with the naked eye: the telescope brought all into crisp view. 

Now she's already asking about our next trip to Arizona! 

Anyway - thanks again and Merry Christmas! 

[JoeSchmuckatelli]

This is cool: stars moving around Sag A:

Watch stars slingshot around the Milky Way’s supermassive black hole | Astronomy.com

 

 

Edited December 26, 2021 by JoeSchmuckatelli

[StrandedonEarth]

1 hour ago, JoeSchmuckatelli said:

@SunlitZelkova @StrandedonEarth @sevenperforce

Thanks for the info / advice on telescopes! 

We saw 3 of the moons of Jupiter and Saturn's rings tonight (despite being in a city).  Kid-girl is stoked! 

Now she's already asking about our next trip to Arizona! 

Anyway - thanks again and Merry Christmas! 

Awesome, good to hear!

 

1 hour ago, JoeSchmuckatelli said:

Pleiades are barely visible with the naked eye: the telescope brought all into crisp view. 

Even with just binoculars, the first time I looked at the Pleiades was “OMG it’s full of stars!!!”

[JoeSchmuckatelli]

14 minutes ago, StrandedonEarth said:

Even with just binoculars, the first time I looked at the Pleiades was “OMG it’s full of stars!!!”

You should see them with a good (read mil-grade) pair of NVGs!  Had a 3-power monocle that would take your breath away.

...

I grew up with a clear view of the Pleiades living in LA.  Was one of my favorite constellations.  Growing up in the West and living in the deserts, getting to see stars was commonplace.  Mountains and high desert plateaus were fantastic.  Milky Way clearly visible, shooting stars, constellations.  

Fast forward to my first deployment at sea with the Marines.  Told all my East Coast Marines that as soon as we were in the middle of the Atlantic the stars would be amazing, given that we would be as far from city lights as possible..

They were not.

Navy navigator explained the effects of humidity to me.

So now I'm a midwest guy, and despite living in a MUCH smaller city than LA, I can't see the stars nearly as well.  Humidity.  Way worse than light pollution.

...

That said: my daughter's reaction to seeing them is something I'll not soon forget!

[Hyperspace Industries]

 What is the densest combustion based rocket fuel when it comes to delta v? Essentially, what combustion based rocket fuel, be it solid, hybrid, or liquid fuel, would give you the most delta v in the least volume?