Summoned Japan - Vol. 3 Ch. 12

[criver]

@SlurpNoodle The heat produced by a strong lightning (one producing temps of 30k) can very well kill a person. People have had 3rd degree burns from lightning (and have also been killed). Note also that the ones present in nature are not sustained for periods as long as 1s:

The brief duration of the exposure frequently limits the damage to the outer layer of skin.

Heat diffusion from a 30k Kelvin medium over a period of 1s will very much vaporise metals, let alone human flesh.

@Needhydra

you are making the mistake of air temp = steel temp.

And you are making the mistake of not knowing what heat diffusion is. 1s is more than enough to transfer enough heat to vaporise metal. Write your heat diffusion PDE in 3D, set Dirichlet boundary conditions with 30K Kelvin at the boundaries of your material, you can even set your material's current temperature to only 273 Kelvin, set a reasonable estimate for the heat conductivity of your material (even if you were to set something unreasonable like 1 I don't think it will make a difference), compute the evolution of the system over the span of 1s.

Also - industrial electric furnaces get nowhere near 30K Kelvin.

 

[elhessan]

@SlurpNoodle true.. but, where will they learn about it? Leilei has the chance to learn science and combined it with magic. But in this series? I don't think the mages has such opportunity just yet. So, they will relying on raw firepower.

@themanj i was comparing to panzerfaust. Would be unfair if i suddenly brought up bigger guns. But, yeah, they still need insane explosion spell to do that.

 

[Needhydra]

@criver the amount of mass that lightning heats in air is so little that its basically a non factor, if it was then humans would be vaporized on contact with lightning but they are not. Do lightning rods vaporize when they are hit? No they dont. People are killed by the electric current from lightning not the heat. So what is heating the metal and burning the people the electric current going through them not the air.

(even if you were to set something unreasonable like 1 I don't think it will make a difference)

man idk 1 is only like 40 times the conductivity of air. With a few grams of mass and a conductivity of less then 1 I don't think it will do much.

Strong lightning will kill you at range you can be a few meters away and die from the electrical shock.

Industrial electric furnaces dont get as hot but what they can do is heat up metric tonnes of material that requires a ton more energy then heating up a few grams of air up to a few thousand k

 

[criver]

@Needhydra

Do lightning rods vaporize when they are hit? No they dont.

Do lighting rods get hit by a 30K lightning sustained for 1s? No they don't.

People are killed by the electric current from lightning not the heat.

Once again - sustain this for 1s even - you'll be vaporised from the heat diffusion. The difference is similar to setting a heat diffusion PDE with initial data, and a heat diffusion PDE with Dirichlet boundary conditions set to 30K - there's a large difference.

These severe injuries are not usually caused by thermal burns, since the current is too brief to greatly heat up tissues;

One second is very long for such temperatures - it will lead to heat diffusion that would melt anything. Think of it this way: put something for 1s on the surface of the Sun.

man idk 1 is only like 40 times the conductivity of air.

Now look up the conductivity of metals. You only need to have sustained lightning hit near enough your tank to vaporise it.

 

[CheerTheDead]

@elhessan

That was thick. I though WW2 tank is around 1/3 the thickness of Modern tank. I were imagining them to be around 2-3cm thick. Didn’t know they were that heavily armoured.

Any WW2 tank you think the mage can effectively deal with using Fireball? I mean any tank that the mage have the best odd against.

 

[elhessan]

@CheerTheDead actually, that's pretty standard for medium and heavy tank... the one that may be affected would be light tank, like M3 Stuart. the armor is 1-2 inches thick.. even so, you need non-stop fireball barrage to create enough heat... but, some explosion will do for this kind of tank...

 

[Needhydra]

@criver IF I am using a material properties chart that lists specific heat capacity, what do you think might be also listed in the same chart idk maybe conductivity.

What you are saying is not lightning, it is dumping the energy of kgs of steel at 30k kelvin at a point touching the tank. Air is not made of kgs of steel nor does it have as much energy as kgs of steel at the same temperature.

So let us look at the issues of vaporizing a tank.
You need like a small nuclear bomb's worth of power to vaporize tonnes of steel, ceramic and flesh in a second that will kill the caster and his allies if things worked like how you say they work.

But hold on at first you said melt way comments ago
1s of very strong lightning hitting a tank can melt some of the thinner/smaller metal parts easy but not the main armor there is just to much mass and not metal and if he does hit the same sport for entire time the heat is more spread out, the roof its kinda thin and is all metal instead of composite aka layers of metal and not metal so hitting that will prob melt it.

Basically you want the impossible aka mathlab land. You want the Lightning to heat the air to 30k k and then for the air to perfectly transfer all its temperature(not energy, it just adds energy I guess) to the entire tank to vaporize it, but only vaporize and state change after all the energy has been dumped in. Normally when stuff state changes it removes energy from the material because it will start to ablatively cool.

So I don't think you are taking all the variables into consideration as this isnt a simple heat diffusion PDE in 1 solid material its more like 1 solid 1 liquid and 2 gases/plasma for just the steel and air not what other crap is in the tank armor. Granted I even forgot to factor electrical resistance from heat(yay late night commenting pretty sure that is also a pde its been a bit since college) which will cut down the melting time of that one square chunk of steel but there is the other 50 tonnes of tank left to go but I am more scared of the ammo cooking off instead of being vaporized.

A WW2 or very early cold war tank with its all steel armor would be pretty melted(more like exploded) but you still need to hit it not be "close."

Also

sustain this for 1s even

Im sorry what mage who would be able to do that (peak power for 1 second.) You are asking people who have no idea how lightning works to cast the strongest form of it about 20 times in a second. Now what mage can do that and not be killed in said second, because by your logic that will melt a tank in a second so wouldn't a human will die way before that.

Let us assume that mages can copy a effect that they have seen before. SO this guy seen this 5% of lightning, seen its effect that were greater at heating then normal lightning and lived. He then needs to show other mages while not dying this new lightning he can cast.

Another question is is the lightning instantly at full power or builds up to full power(aka prob wont get to max power till some time after it hits) for all the weird slow speed lightning mages cast.

 

[criver]

@Needhydra

What you are saying is not lightning, it is dumping the energy of kgs of steel at 30k kelvin at a point touching the tank. Air is not made of kgs of steel nor does it have as much energy as kgs of steel at the same temperature.

It's the air near the lightning bolt that is brought to 30K Kelvin for strong lightnings, not some imaginary casing of steel. If that 30K "air" is in contact with your tank heat diffusion will occur. You have yourself a parabolic heat diffusion problem with Dirichlet boundary conditions set to 30k and a relatively high diffusion factor due to the metal. Your tank will vaporise provided enough time (and 1s should be more than enough at that temperature).

1s of very strong lightning hitting a tank can melt some of the thinner/smaller metal parts easy but not the main armor

You can run a simulation if you want - it's not the thinner/smaller parts.

Normally when stuff state changes it removes energy from the material because it will start to ablatively cool.

Not enough considering that you're dealing with a temperature higher than the surface of the Sun. Look up phase transition of metals, 30K is in a totally different league.

Basically you want the impossible aka mathlab land. You want the Lightning to heat the air to 30k k and then for the air to perfectly transfer all its temperature

This is not what I said. Also, it is MATLAB not MATHLAB. I explicitly mentioned that even if you were to reduce the conductivity hundreds of times it won't matter at that temperature - basically even if your tank was made out of air, it would still heat up enough to kill anything within/make it nonoperational. Unfortunately, I cannot teleport you a tank to the surface of the Sun for 1s to show it to you.

Im sorry what mage who would be able to do that (peak power for 1 second.)

That's fantasy land premise - it's basically up to the author (obviously it is not the case in this work). For all I care the author can make it so a mage's fart blows up the Earth. It's clearly that in this instance the manga is about "nerdgasms induced by oh how mighty muh technology would be in my thought up fantasy setting" - said otherwise - mental masturbation for military otakus.

The point is that as long as you allow magic that can invoke the forces of nature in your premise then your army is done in by tornadoes, lightnings, tsunamis, floods, negative temperatures, earthquakes, etc. So rather than try to argue against actual physical phenomena and perform mental gymnastics to deny them, just accept the story for what it is - the author can always find an excuse why magic in his settings is inferior - that's not the goal of the manga, the goal is to have military otakus live out their fantasies.

 

[Ehlwood]

I made tuna sandwich anybldy wants some?

 

[nahui3]

I got the popcorn

 

[gundulgondrong]

dont forget to tech up kid..

 

[Winchan]

Infantry Battle, you say?

Wanna see some Systema? Kali Arnis? Special Operations techniques?

Or something much simpler like AP/HE Shells and from Tanks and Machine Guns on APCs?

Or perhaps an open barrage of Military-Grade Explosives and Assault Rifle rounds?

pick your poison.
I'll sit here, relax and enjoy the view.

 

[SlurpNoodle]

@Kaiser92
"But how expensive is it in term of GDP? How much did they use to spend on infantry's equipment back in the day?"
Are you talking WWII or the mideval period of the troops the Japanese are fighting? The former will require research I don't want to do to be honest. The latter: who knows?

"Oh you meant what the US did with the Axis after WW2? I don't think this Japan can do what the US did back then though, not even close."
Yes, exactly that. I have mixed feelings about whether Japan could do it, in terms of realistically accomplishing it, but this is a fictional story and a lot can be hand waved.

"Source? Vietnam and Korea stayed as China's tributary for quite a long time, I think > 1000 yrs."
Using your examples, how long did Vietnam and Korea stay as France's and Japan's vassal states in the 1900's? Since communications and living standards improved in the modern day, colonialism lasts shorter and shorter. Japan is bringing 21st century ideas and techniques to a world that ranges from medival to early/mid 20th century.

"Lol imma disagree, I know they are bad, but they are not THAT bad, especially in the past."
Well, the past is the past, to quote LP Hartley: "The past is another country and they do things differently there." It's OK to disagree.

"Why take thing outta context?"
Is it? I was just quoting and replying to your initial comment in the context of this story, you didn't quote the entire litany of Sun Tzu. I feel that to comment on Sun Tzu entire litany based upon your small quoting of it would be taking it out of context

"Hurting local culture is too far but killing thousands of ppl isn't???"
Hurting the local cultures of the nations who are allied with or are on friendly/neutral terms with Japan, not the kingdoms who are invading the murdering the inhabitants of Japan's allied nations.

"Bruh I just quoted a Chinese guy on how to win war, I don't even like the CPC!"
It's cool, sorry if you took it that way. I'm just giving my take on the CCP/CPC interpretation of "soft power"

"The first line even read: "In the practical art of war"..."
Yeah, I understand that Sun Tzu was supposedly a general, and to a general, everything is about the art of war, I understand the carpenter and hammer analogy. Unfortunately, passages from his work gets slung around without much deep understanding. For example, the CCP/CPC seems to be exclusively applying Sun Tzu's works, without any diplomacy.

 

[SlurpNoodle]

@criver
"It's the air near the lightning bolt that is brought to 30K Kelvin for strong lightnings, not some imaginary casing of steel. If that 30K "air" is in contact with your tank heat diffusion will occur. You have yourself a parabolic heat diffusion problem with Dirichlet boundary conditions set to 30k and a relatively high diffusion factor due to the metal. Your tank will vaporise provided enough time (and 1s should be more than enough at that temperature)."

Now you're confusing temperature with energy transfer. One is a byproduct of the other and not in the way you've been presenting.
You're using highly technical terms without understanding the foundational concepts. Rather than trying to "win the argument" I'd suggest you go and educate yourself a bit more on physics and possibly materials engineering, in particular thermodynamics.

 

[SlurpNoodle]

@Needhydra
" read my other post lighting is mostly dangerous to infantry as it will stop you heart in a aoe from the strike but a vehicle will protect you because of the metal shell acting like a Faraday Cage.(open top can get you killed)"

Lightning can kill infantry, not so much thermodynamic energy transfer as crivier is claiming (burning you to a crisp or vaporization), but more due to biological affects on the human body, such as fibrillation or just plain stopping of the heart due to a current passing through it. The reason why vehicles may not be as affected, especially metal tracked vehicles like tanks, is because they are grounded and metals tend to conduct electricity far better than organic structures like trees, or people. I would argue that open topped vehicles are more dangerous because the lightning may hit the person riding it before being grounded out into the vehicle and then the ground.

 

[criver]

@SlurpNoodle

One is a byproduct of the other and not in the way you've been presenting.

I would love to see you try explaining how it's "not the way I have been presenting it". Go on, I'll laugh.

You're using highly technical terms without understanding the foundational concepts.

> heat diffusion equation
> highly technical terms
U wot m8? One would assume that if you don't even know basics you would refrain from trying to argue. Dunning-Kruger effect much?

What's next? You don't know how heat transfer works? Apparently not.

 

[SlurpNoodle]

@elhessan
"true.. but, where will they learn about it? Leilei has the chance to learn science and combined it with magic. But in this series? I don't think the mages has such opportunity just yet. So, they will relying on raw firepower."

I don't know about the mages from the aggressor kingdom, but the mages from the allied nations may have had the same opportunities that Leilei did to learn science. I can't help it if they didn't have the capability to combine it with magic as Leilei did....but even in Gate, Leilei was considered an odd mage. Perhaps there was something in her thought processes that made it particularly suitable to combine science and magic.

 

[SlurpNoodle]

@criver
"> heat diffusion equation
> highly technical terms
U wot m8? One would assume that if you don't even know basics you would refrain from trying to argue. Dunning-Kruger effect much?

What's next? You don't know how heat transfer works? Apparently not."

With electricity, before you even get to the heat diffusion equation, you have to calculate the electricity to thermal energy equation first. Y'know, all those pesky symbols expressing units of energy in "Joules" and "Watts".

 

[criver]

@SlurpNoodle

With electricity, before you even get to the heat diffusion equation, you have to calculate the electricity to thermal energy equation first.

Was that it? I expected better from you. I don't need to calculate shit considering it is known. Go do a cursory search then come back.

 

[SlurpNoodle]

@criver
"> heat diffusion equation
> highly technical terms
U wot m8? One would assume that if you don't even know basics you would refrain from trying to argue. Dunning-Kruger effect much?

What's next? You don't know how heat transfer works? Apparently not."

With electricity, before you even get to the heat diffusion equation, you have to calculate the electricity to thermal energy equation first. Y'know, all those pesky symbols expressing units of energy in "Joules" and "Watts".