Science News Thread (for articles that don't relate to ongoing discussions)

[magnemoe]

10 hours ago, kerbiloid said:

So, when I was suggesting exactly that for cooling the Venereausian habitats with a turboexpander, powering it with an external nuke reactor, they were laughing "Ew! Ew! You dunno da Carnot cycle!"

But when it has a brand label and called "heat pump", it is "Wow! Wow! Heat pump is da best!"

A well-educated KSP player is so well-educated...

Btw, the wiki doesn't explain the word "compressed". It is still compressed by the power of air and fire elementals power station.

Remember that, I suspect you had to do an two stage refigurator here as you need to make your hot side so hot it looses heat on Venus and the reactor mostly add more heat who has to be radiated away. 
And that is the cool side of the reactor loop, the hot is limited by materials. 
Theoretical possible but you need to design an reactor specific for this. 
It would be heavy, Guess above system also is but it don't matter much as is part of an static industrial process. The electricity used will just add to the heat.

Now I'm questioning if you could use this in an steam turbine to get extra power because the relatively low efficiency of steam turbines and they are pretty good at getting most of the energy out? 

[kerbiloid]

6 hours ago, magnemoe said:

and the reactor mostly add more heat who has to be radiated away. 

The reactor is placed at the opposite side of the hill,and is being cooled by the 480°C cold Venusian "air".
It feeds the turboexpander which transfers the expansion/compression work to similar "air", warming it from 480 to 700..800 and exhausting up with a smoke pipe, separated with a reflective screen.

6 hours ago, magnemoe said:

Now I'm questioning if you could use this in an steam turbine to get extra power because the relatively low efficiency of steam turbines and they are pretty good at getting most of the energy out?

Hot parts are outside of the habitat hull. They are connected with pipes.

[JoeSchmuckatelli]

There are some interesting and early reports of the recovery of honey bee populations.  The most interesting are pay walled. 

Why interesting: several years of bee-pocalypse reporting about the challenges of agriculture practices (pesticides, moniculture, etc) climate change, disease, parasites and loss of food sources /habitat. 

Why it matters: bees are for all intents and purposes a domesticated species critical to our food supply.  Farmers and agribusiness responded to the crisis and developed multiple strategies to stabilize and protect bee populations. 

Quote

We've added almost a million bee colonies in the past five years. We now have 3.8 million, the census shows. Since 2007, the first census after alarming bee die-offs began in 2006, the honeybee has been the fastest-growing livestock segment in the country!

Washington Post 

[DDE]

6 hours ago, JoeSchmuckatelli said:

There are some interesting and early reports of the recovery of honey bee populations.  The most interesting are pay walled. 

Why interesting: several years of bee-pocalypse reporting about the challenges of agriculture practices (pesticides, moniculture, etc) climate change, disease, parasites and loss of food sources /habitat. 

Why it matters: bees are for all intents and purposes a domesticated species critical to our food supply.  Farmers and agribusiness responded to the crisis and developed multiple strategies to stabilize and protect bee populations. 

Washington Post 

Meanwhile I'm seeing someone basically cry in the Detroit: Become Human forums about how profound a warning a small fluff article about the extinction of bees is.

[kerbiloid]

No bees - no honey.
No honey - no normal shilajit.

No bee venom and honey - no normal natural shilajit.

Bees are important.

[DDE]

Speaking of dumb questions: why is no-one trying to bolt a ramjet onto an APFSDS anti-tank dart? This seems like a natural combination.

A search yeilded a couple of patents, including one by people well-placed to do something about it (a munitions subsidiry of Roscosmos)

https://yandex.ru/patents/doc/RU2724626C1_20200625

Bonus: they use a drop-down nozzle with attached fins. Earlier proposals seemed to make do with a much smaller combustion chamber and a rather ordinary dart, but the patent description cites poor Isp and loss of the fins' function when they find themselves in the exhaust stream.

[SunlitZelkova]

4 hours ago, DDE said:

Speaking of dumb questions: why is no-one trying to bolt a ramjet onto an APFSDS anti-tank dart? This seems like a natural combination.

Idk, but that concept vaguely reminds me of the MGM-166 LOSAT's rocket propelled long-rod penetrators.

[TheSaint]

5 hours ago, DDE said:

Speaking of dumb questions: why is no-one trying to bolt a ramjet onto an APFSDS anti-tank dart? This seems like a natural combination.

A search yeilded a couple of patents, including one by people well-placed to do something about it (a munitions subsidiry of Roscosmos)

https://yandex.ru/patents/doc/RU2724626C1_20200625

Bonus: they use a drop-down nozzle with attached fins. Earlier proposals seemed to make do with a much smaller combustion chamber and a rather ordinary dart, but the patent description cites poor Isp and loss of the fins' function when they find themselves in the exhaust stream.

So, prefixing my post with, "I am not an engineer, I am a guy on the Internet using his intuition,"

You take your APFSDS round, and you replace a significant fraction of the mass in your payload with mass that isn't penetrator. I mean, even if go to the bother of constructing that ramjet out of depleted uranium, it's not going to make a difference when it comes to actual armor penetration. The only part that's going to matter at point of contact is the penetrator.  You can only push so much mass out of your cannon before it becomes ineffective. So the ramjet mass is going to do nothing but penalize you when it comes to initial muzzle velocity and penetrator mass.

If your target is 100 yards away, your ramjet-enhanced round is a complete loss compared to conventional APFSDS. I don't need any sort of software or calculator to tell me that. With a muzzle velocity measured in thousands of yards per second, there is no possible way that a ramjet is going to make up that initial muzzle velocity penalty in 100 yards. Your ramjet will be operating for milliseconds at that point, at best.

So the question is not, "Is a ramjet-enhanced round always better?" The question is, "At what range does a ramjet-enhanced round make up  for its initial velocity penalty and become a better round than a conventional APFSDS?" Or, maybe the question is, "Does the ramjet-enhanced round ever make up for its initial velocity penalty?" If there is a break-even range, do I send my tanks out with a mix of ramjet and non-ramjet rounds? Which do they keep in the chamber? Is it worth adding one more decision to the already decision-overloaded troops in the field?

Or (since everything is run by bean-counters now), perhaps a better question is, "Does the ramjet-enhanced round provide a cost benefit on the battlefield beyond that provided by a conventional APFSDS round?" Can I kill more tanks with ramjet-enhanced rounds? Or can I kill more tanks with the greater number of conventional APFSDS rounds that I can provide with the same amount of money? What did my General Dynamics lobbyist tell me this week?

Again, I am not an engineer. Or a tanker, for that matter. (Paging @JoeSchmuckatelli) Just asking the questions that immediately come to mind. I guess it doesn't seem like a dumb question to me.

[DDE]

11 hours ago, SunlitZelkova said:

Idk, but that concept vaguely reminds me of the MGM-166 LOSAT's rocket propelled long-rod penetrators.

I know, but that's an ATGM option, not a simple attempt to cram more velocity.

9 hours ago, TheSaint said:

With a muzzle velocity measured in thousands of yards per second, there is no possible way that a ramjet is going to make up that initial muzzle velocity penalty in 100 yards.

Good point. Reminds me of the Gyrojet's problem.

9 hours ago, TheSaint said:

since everything is run by bean-counters now

Hey, don't knock the bean counters. They're quite important when acquisition numbers run into the tens and hundreds of thousands.

[JoeSchmuckatelli]

16 hours ago, DDE said:

bolt a ramjet

 

10 hours ago, TheSaint said:

the penetrator

TheSaint's analysis sounded sound to me. 

The only ramjet penetrator thing I've heard spoken about in any terms that seem remotely plausible is as a strategic rather than a tactical weapon.  

Given that APFSDS works - why strap an engine on it? 

[JoeSchmuckatelli]

FWIW - because tanks have huge guns they don't really need an engine to get the penetrator up to speed.  Big boom = fast round. 

Where you might want to get a hypersonic engine strapped to a penetrator is a future manpad scenario where active protective systems can defeat the top attack HEAT / HEDP systems (aka Javalin) and need to revert to kinetic kill techniques. 

[JoeSchmuckatelli]

Ofc we'd need to get hypersonic engine tech miniaturized 

[Codraroll]

1 hour ago, JoeSchmuckatelli said:

FWIW - because tanks have huge guns they don't really need an engine to get the penetrator up to speed.  Big boom = fast round. 

Where you might want to get a hypersonic engine strapped to a penetrator is a future manpad scenario where active protective systems can defeat the top attack HEAT / HEDP systems (aka Javalin) and need to revert to kinetic kill techniques. 

I suppose it could also have its use for naval guns, where you have a bigger calibre to work with and longer ranges to be covered by the projectile.

Then again, at those ranges, you would probably want a rocket booster to get the hypersonic penetrator up to speed anyway, and just launch it as a missile instead of bothering with those huge and cumbersome guns.

[DDE]

12 minutes ago, Codraroll said:

Then again, at those ranges, you would probably want a rocket booster to get the hypersonic penetrator up to speed anyway, and just launch it as a missile instead of bothering with those huge and cumbersome guns.

Well, Nammo's dead-set to fit a ramjet into a 155 mm howitzer shell, although IIRC the US cancelled their development order. 

[StrandedonEarth]

Would it not be simpler to just build a solid rocket motor into the base of the penetrator, to be ignited at the best point in the trajectory?

[Codraroll]

1 hour ago, DDE said:

Well, Nammo's dead-set to fit a ramjet into a 155 mm howitzer shell, although IIRC the US cancelled their development order. 

Artillery shells and tank shells are kind of different beasts, though. For an artillery shell, you'd use measures like this to extend the range of the shell, since its job is to hit targets as far away as possible. A tank shell, meanwhile, fires in a near-straight line at relatively close ranges, and needs to pack as much kinetic energy as possible when it impacts the target, preferably as quickly as possible after firing.

Although the reasons why it doesn't work tends to be the same for either: fitting a ramjet into the relatively tiny package of the shell takes away space for explosives and fragmentation material, so the ramjet shell will have a rather puny effect wherever it's hitting compared to a conventional shell. It might have its use against time-sensitive high-value targets, though, for instance, a high-ranking officer who visists the troops to deliver a rousing speech to motivate his men to drive golf carts into the minefields for the glory of the mad czar, or a helicopter that lands to drop off troops or restock ammunition. Those are usually key targets that present themselves for a very short duration, and need to be hit right after they are spotted before they are gone to have another drink again.

However, I don't think it'd be ideal to make such ammunition for the 155 mm guns. Guided rocket artillery already have the range, higher effect on target, and the mission profile fits better into its part of the organization chart: you don't need to give the long-range "surgical strike" missions to the battalion-level artillery with the 155mm guns, whose job it is to spew out shells at the enemy forces in the battalion's rather limited operation area. Better give the job to the more specialized brigade artillery, with heavier rocket artillery and a purpose that's more along the lines of "strike where needed in a very large area". They also say ATACMS, a rather heavier missile system, is great for "assassinations" like this. They have a short flight time, a long range, and need little time to prepare a fire mission (unlike, say, cruise missiles, which need a whole trajectory to be plotted). And they come in at very high speed, making it hard for the target to prepare for their arrival. They're ideally suited to fire at stuff like, say, a train loaded with fuel or ammunition just as it passes a key bridge.

[darthgently]

1 hour ago, Codraroll said:

A tank shell, meanwhile, fires in a near-straight line at relatively close ranges, and needs to pack as much kinetic energy as possible when it impacts the target, preferably as quickly as possible after firing.

I thought indirect fire was a thing with newer tanks, though not their primary role.

But yeah, even so, a ramjet seems more appropriate for a target well beyond more than just over the horizon

[kerbiloid]

7 hours ago, StrandedonEarth said:

Would it not be simpler to just build a solid rocket motor into the base of the penetrator, to be ignited at the best point in the trajectory?

If add an ablator layer at the rear end of the projectile, and insert a powerful laser into the barrel from th back, this would be a double-purpose Ballistic Laser Gun.

When there is a projectile in the barrel, it vaporizes the ablator, and throws the projectile either on straight hypersonic, or on curved ballistic trajectory, depending on the laser power.
With empty barrel, it's a regular laser gun.

Also useful with buckshot rounds.
Firstly the laser is weak and accelerates the shrapnel pack to the end of the barrel.
Once it's outside, the laser makes a pulse to melt and spread it in a cone.

By varying the laser spectrum, they can use red lasers for bad owners, blue for the good ones, and green for the neutrals.

[magnemoe]

8 hours ago, darthgently said:

I thought indirect fire was a thing with newer tanks, though not their primary role.

But yeah, even so, a ramjet seems more appropriate for a target well beyond more than just over the horizon

One issue is that tank guns can not be elevated very high. The reason self propelled artillery's has so large turrets is to allow for high elevation. 
The indirect fire part is mostly just an module in the fire control computer.  

[JoeSchmuckatelli]

9 hours ago, darthgently said:

ndirect fire was a thing

Old and new.  All you need is the doohickey called a gunners quadrant.   Russia used the Armata this way so they could say it was 'combat tested' without risking any.  We could do it with Sherman or Abrams.  Hell, we can do it with a M240G or a. 50 cal. 

 

No time to Google but if memory serves - aren't ramjets inefficient in lower atmosphere?  So won't the ramjet penetrator idea be an airlaunched platform for guidance and speed that then gets ejected when the kill vehicle goes to terminal phase? 

[magnemoe]

33 minutes ago, JoeSchmuckatelli said:

Old and new.  All you need is the doohickey called a gunners quadrant.   Russia used the Armata this way so they could say it was 'combat tested' without risking any.  We could do it with Sherman or Abrams.  Hell, we can do it with a M240G or a. 50 cal. 

Back before WW 1 volley fire at extreme range as out to 2000 meter was an thing, this is why you can see rifles with sights with settings for this extreme range. I assume this was mostly for harassments and making the area unsafe and it would be more effective on an large group of enemies. 

[JoeSchmuckatelli]

@Gargamel - because I do not have access to S&Sf sub I need to post a question here.  Will you move it to the appropriate sub?

Question about 'Paring Ladders' - can anyone help me with a project for school?  I want to teach students about paring ladders and moving heavy loads.  I just Don't know how to figure out how much a paring ladder with 10 foot legs might pull 

 

Any help appreciated! 

 

 

[darthgently]

13 minutes ago, JoeSchmuckatelli said:

@Gargamel - because I do not have access to S&Sf sub I need to post a question here.  Will you move it to the appropriate sub?

Question about 'Paring Ladders' - can anyone help me with a project for school?  I want to teach students about paring ladders and moving heavy loads.  I just Don't know how to figure out how much a paring ladder with 10 foot legs might pull 

 

Any help appreciated! 

 

 

Because the rope is tied to near the top there isn't much leverage gained in that respect.  What I see happening is the legs of the ladder having more traction and his being able to use his massive tactical pear shape to allow gravity to do a lot pulling (combined with his grip).  The rope pulling somewhat upward on the log reduces friction between ground and log. 

So I don't see leverage so much as increasing traction for the ladder, decreasing friction for the log, while pulling the log horizontally, and using his body weight to activate all that.

Cool!

Now if the rope were tied significantly lower than his hands then leverage would be a bigger deal (but lifting force on log would lessen)

[JoeSchmuckatelli]

12 hours ago, darthgently said:

Because the rope is tied to near the top there isn't much leverage gained in that respect.  What I see happening is the legs of the ladder having more traction and his being able to use his massive tactical pear shape to allow gravity to do a lot pulling (combined with his grip).  The rope pulling somewhat upward on the log reduces friction between ground and log. 

So I don't see leverage so much as increasing traction for the ladder, decreasing friction for the log, while pulling the log horizontally, and using his body weight to activate all that.

Cool!

Now if the rope were tied significantly lower than his hands then leverage would be a bigger deal (but lifting force on log would lessen)

There is another vid I've seen where the rope is lower. 

Funny thing is that I want to do it because I got asked about Aliens the Pyramids and Stonehenge. 

 

My reply is that people are way cooler than they think - so I plan to take them all outside to move heavy things. 

[kerbiloid]

On 4/14/2024 at 12:54 AM, DDE said:

why is no-one trying to bolt a ramjet onto an APFSDS anti-tank dart? This seems like a natural combination.

The WH40k bolt-guns are nodding here.