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The Official "Quick Question" Thread


boris_73
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I'm sure I am overlooking something obvious however;

 

Q. Instabilities, of varying frequencies, grow exponentially in a superheated plasma. Controlling these fluctuations is an integral part of successfully harnessing fusion. Is it not possible to harness the increased amplitude of the fluctuations and damp them by an inverting the amplitude of the instability. There will obviously be some delay but surely the feedback loop could be calibrated such that the resulting instability does not destabalise the entire system?

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  • 2 weeks later...
Ok' date=' yes I'm completely laser illiterate.

Q.

I was wondering since lasers are used in cleaning paintings, and conserving old cathedrals, could they be utilized in everyday housework? Such as cleaning counters and carpets instead of using chemical products.[/quote']

 

Probably, but it's overkill. AFAIK what you are doing is ablating the surface by the local heating of the laser, so that the underlying material isn't damaged. It's slow, and unless your countertop needs to be protected from damage, use a sponge and detergent.

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Well if by crap you mean it costs a lot for small products, it's because of labor costs. In America we have labor laws so workers have to be paid over $.50 a day. That raises an employer's costs to make the good, which in turn brings up the price. Also there are laws regulating working conditions, which also raises costs (if you doubt the need for this read The Jungle by Upto Sinclair.)

 

These kind of things jack up the prices of everyday items if they're bought in America. That's why most products (consumer products) are imported. Most Americans have serivce jobs (i.e. doctor, lawyer, teacher, police officer, waiter, assassin etc)

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Probably, but it's overkill. AFAIK what you are doing is ablating the surface by the local heating of the laser, so that the underlying material isn't damaged. It's slow, and unless your countertop needs to be protected from damage, use a sponge and detergent.

 

 

Thanks Swansont for answering. But if the laser cleaning process could go much quicker would it still be better to use chemical products around the house?

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  • 2 months later...

just a quicky about Crystal shape names (Chemistry).

 

the crystal is Cubic but long (rectangular) what is this called properly?

 

I have here BCC or FCC (or CUB) as the only listed options in my data book, Body-center cubic and face-center cubic respectively.

 

anyone know?

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just a quicky about Crystal shape names (Chemistry).

 

the crystal is Cubic but long (rectangular) what is this called properly?

 

I have here BCC or FCC (or CUB) as the only listed options in my data book' date=' Body-center cubic and face-center cubic respectively.

 

anyone know?[/quote']

 

 

This page lists different Bravais lattice configurations. Looks like tetragonal and orthorhombic fit your description.

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  • 4 weeks later...
ok...

 

when you write a chemical symbol like Mg you could write Mg (s) coz Mg is a solid... H2O is a liquid so (l)? but (aq) is sumin disolved in water... so how would you write H2O (??)..... prob (l) but im not 100% sure!?!?!?

liquid is a state by itself H2O can be a solid in ice' date=' liquid beyond 0 deg C and vapour (gas) beyond 100 Deg C under normal conditions of pressure, similarly all gases can be in either of state. It is the property of matter. Refer this animation on matter

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  • 1 month later...

Yeh but milk boils over much MUCH easier. I think it is due to the proteins holding the bubbles intact hence increasing the over all volume of the milk/air/bubbly mixture. If you see what i mean. Atleast thats what seems to happen anyway.

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What creates the earths magnetic field? (i know it involves the molten core but thats about it lol)

 

With quantum physics, how exactly does 'percieving' something collapse all its probabilities? and by percieving does it mean as in the preception of the light given off or some other way of measuring activity?

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With quantum physics, how exactly does 'percieving' something collapse all its probabilities?

 

There are kinda two questions here but they merge into one another.

 

Take the good ol' fireing particles through 2 slits, say we use C60 particles for the sake of argument (which has been done). These produce a nice interfearence pattern. If we measure through which slip they have travelled we need to create a way of doing this, so lets say we use a very very low energy light gate over each of the two slits. Whenever a particle passes through either of the slits it gets hit by a photon, the photon gives it enough energy to change it's velocity and this destroys the interfearence pattern.

 

The fact you have applied a small amount of energy to the particle means you have changed it in some way, changed it's wavefunction, and the measurement you make will be of this changed wavefunction. There is an exception to this rule and that is when the system is in an eigenstate of the observable (what you are measureing), in which case the system remains the same afterwards.

 

and by percieving does it mean as in the preception of the light given off or some other way of measuring activity?

 

Precepting an quantum system, just means measureing something about it. Which is very often done with photons which is why terms like observables are used.

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oh ok that make sense. Then why do i always read about those trippy quantum theories that we (as in the mind) chooses when a partical is in a certain place (like in 'What the bleep do we know?'). Kind of like the conciousness is taken a role in bringing a certain thing into reality? I know this is fairly pseudo-science however i don't get how this would be a logical conclusion given the explaination you just gave me. (i realise that this is turning into a long question sorry)

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Sorry if this is a little incoherant, but hypothetically do you think its plausable that our universe could have been created entirely of anti matter. If so would the antimatter just be matter and vice versa?.

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What you just did is change the names, anti-matter and matter are just a description of two things that cancel each other out. And it wouldn't be possible for the world to be mostly anti-matter or matter even, there needs to be equal proportions of both in order for the big bang theory to work.

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  • 2 months later...

Really silly question I know, but I cant work it out...

 

What is it that accounts for the difference in cooking time between quick cook pasta (the one that takes 5 minutes in boiling water) and normal pasta. Are they made from different ingredients or is one partially cooked already?

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What do you mean by "normal pasta"? Do you mean fresh pasta?

 

This is a total guess: Fresh pasta already has liquid in it so absorbs water (when cooking) quite slowly, whereas dry pasta is dry so it quickly absorbs water.

 

Also the shape of pasta often makes a difference. Imagine cooking a fat lump of pasta compared to small, thin pieces.

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I'm talking about dry pasta, almost all dry pasta and spaghetti takes 10 minutes to boil, pretty much regardless of size shape etc however you can also buy quick cook pasta (also dry) which only takes a few minutes in boiling water.

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