sga

I had this effectively a shower thought idea - why don't we have ceramic 3d printing?

Let me clarify - before posting, I looked it up, and I could not find exactly what I was looking for. There are already commercial offereings for Clay 3D printing, but that is not forming the ceramic in situ, we are depositing what is effectively ceramic in a solvent, and drying it. What I was thinking was making the ceramic on site.

Here is a example setup

• Imagine a regular polymer 3D printing setup

• imagine instead of filament, we have a tank of Ca(OH)~2~ (calcium hydroxide, or slaked lime) (not necessarily just this, but for example, consider this combination)

• imagine we instead of droping a full thread like layer of semi-solid polymer, we form a trail of really tiny water drops

• we sprinkle in Ca(OH)~2~ onto the drops (or this step can be skipped if we can pre mix it with water, and then somehow figure how to deposit really tiny drops of what is effectively a very strong base

• now we let CO~2~ in, and form CaCO~3~

• deposit a layer to fill voids in this layer (we dropped a non continous strings of drops earlier)

• evaporate remainning water

• repeat this step until this layer is complete.

• repeat process for next layer

Now I can think of many problems here

• how to handle very strong base - maybe a tip of refractory alloys, or something like Inconnel (or Ni Cr alloys in general), or ceramic (maybe alumina) coated metal (probably cheapest, but hard to make)

• how to control solidification - we are effectively doing a solidification reaction, and growth of crystal would largely be dependant on the crystal facettes, and we would not be able to have any sharp angles. Also, we would not be able to have a very small width with this.

• surface tension of water will not allow to easily create uniform small dots - only thing I can think of is using something mechanical to hit the water droplets at tips to effectively launch tiny droplets. (Imagine shuriken (stars or blades) breaking droplet, and water landing) - still we would not have control

• how to control solidification rate in exothermic process - maybe easy, but we would need something like fans or coolant, otherwise we would form big drops at a spot due increased nucleation rate

• how to introduce CO~2~ fast enough - we would have to have a very strong CO~2~ environment, somehow not let it solidify at tip. Also this reaction is very slow (maybe that is only the case at bulk solidification). Maybe the whole process would be very slow

Does this process already exist? If it does - any resources related to it would be helpful. If not, Why? Is it because we have not been able to solve the issues I listed, something I did not list? Would this be practical (economically)? I can definitely see both artistic and engineering use cases, and both of those can allow some big budgets.

Old title - Tolerance - Is violence ever justified?

For reference - https://lemmings.world/post/19791264 and all comments below the post about tolerance and non-tolerance

is it too naive for me to believe any and every lives matter? I do understand if someone is coming for my life, and i stop him by retaliating back, most nation's laws would deem me innocent, maybe even most people will - but was it right?

It has not happened with me yet, and this is post is not politics related, a general discussion about tolerance, but I dont know how will I respond to such a situation, Is there a correct approach?

I know in a imaginary utopia - we can have a society where everyone thinks any violence, or for that matter, any evil deed is evil. And I know real world is far from being a utopia, but i believe most people can differentiate between good and bad. In my opinion, most people who do such acts are not really doing it because they enjoy it, some do because they have to, some think they have to, and they have been brain washed.

I also think if we ask a binary (yes/no) question to everyone - Is violence justified" - most people will vote no. I know there would be some exceptions (even in perfect utopia's like N. Korea, lords only get like 99% majority)(/s).

Now if we change question - "Is violence ever justified" - many will now vote yes, and start listing out situations where they think it is valid.

This question was also brought up in Avatar. For people who don't know - should Aang (a person with firm opinions, and more importantly a child - 12(112) years old) kill Lord Ozai (for now, consider him embodiment of evil for simplicity, but still a human). Many shows get away from asking, by basically having monsters (non human) as the opponent, so it is does not feel morally wrong. But here the question was asked. His past lives (in this world reincarnation exists, and aang is the Avatar - person who can control all elements) also suggested he should kill him, and he is tethered to this world, and this is no utopia ......... In the show they got away with basically a divine intervention.

Maybe here is my real question - Is it correct to have your morals be flexible?

Now for my answer, I have almost never felt correct labeling people good or bad, I have almost always treated people depending on what the situation expects me to (maybe how I feel I should be treating). In some sense I have a very flexible stance, and in some others, I dont. For example - I never cheat on exams or assignments - I can't justify cheating, If I am getting poor marks, then I should prepare well. But If someone else asks me to help them cheat (lets say give assignment solutions) - I dont refuse either, as I have understood, even though judging people by a few numbers is bad, world still does that - mostly to simplify things, and in that sense, a higher grade for anyone is better for them.

I dont even know what can be a answer. I dont know if it exists, or it can exist, I am not really trying to find it either, consider this just a rant at clouds.

edit - I am not asking a binary question - you are not expected to answer a yes or no, see the line just above this edit. It is not even really about violence - it is about morality

edit 2 - Changed title, old 1 is still here for full context. I dont know why I chose that title. I am not blaming anyone who answered on the basis of title, It was my bad to have some title, and ask a "not really orthogonal but generalised question" in the middle, hoping people answer that, some one did, I thank them. Many people have written (or in similar vein) - violence should be be avoided, but not when it the last thing. I understand this general sentiment - but according to me - having a excuse to ever do violence allows you to have loop hole, just blame the circumstances.

Someone gave a situation where they would do violence - someone trying to assault a kid - and I agree I would too (If I would be in such a situation).

I had a small back and forth with someone about morals - my stance is morals are frameworks to choose if a action is moral/immoral. And then the question is really how rigid should your moral framework be, and should it depend on background of people in consideration?