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Vacuum

vacuum

Origin: L, fr. Vacuus empty. See Vacuous.

1. (Science: physics) A space entirely devoid of matter (called also, by way of distinction, absolute vacuum); hence, in a more general sense, a space, as the interior of a closed vessel, which has been exhausted to a high or the highest degree by an air pump or other artificial means; as, water boils at a reduced temperature in a vacuum.

2. The condition of rarefaction, or reduction of pressure below that of the atmosphere, in a vessel, as the condenser of a steam engine, which is nearly exhausted of air or steam, etc.; as, a vacuum of 26 inches of mercury, or 13 pounds per square inch. Vacuum brake, a kind of continuous brake operated by exhausting the air from some appliance under each car, and so causing the pressure of the atmosphere to apply the brakes.

(Science: medicine) vacuum pan, a glass tube provided with platinum electrodes and exhausted, for the passage of the electrical discharge; a geissler tube. Vacuum valve, a safety valve opening inward to admit air to a vessel in which the pressure is less than that of the atmosphere, in order to prevent collapse. Torricellian vacuum. See Torricellian.


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Urgent:Algal Oil Extraction..suggestions

... (but those are much less frequent), maybe there is one in the same building. And others can go much higher... - Also for heat drying, a rotating vacuum evaporator (aka speedvac) which heats under a vacuum could help, but AFAIK you will not be able to put tubes much bigger than 50ml (and even ...

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by canalon
Fri Jul 17, 2009 10:53 am
 
Forum: Microbiology
Topic: Urgent:Algal Oil Extraction..suggestions
Replies: 1
Views: 183

a SUPER DUPER DIFFICULT QUESTION!!!! PLEASE HELP!!!!!!

There is one additional component - space. Lower-pressure gas is fewer molecules in space - closer to a vacuum. What's happening is essentially diffusion, but the particles move faster because there's almost nothing in their way. In liquid, there are more collisions and redirections ...

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by Darby
Mon Apr 06, 2009 7:10 pm
 
Forum: General Discussion
Topic: a SUPER DUPER DIFFICULT QUESTION!!!! PLEASE HELP!!!!!!
Replies: 13
Views: 996

Re: Electrons... To be or not to be...

The physicists offer a stranger story about the vacuum, where quantum fluctuations cause spontaneous appearance of virtual particles. http://en.wikipedia.org/wiki/Virtual_particles In particular, scroll down to the section "Manifestations" ...

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by jonmoulton
Wed Feb 11, 2009 11:14 pm
 
Forum: General Discussion
Topic: Electrons... To be or not to be...
Replies: 14
Views: 683

Electrons... To be or not to be...

Yes, a vacuum contains no electrons. A neutron contains no electrons, a proton contains no electrons. There is a flow(not constant) of electrons because some atoms will lose and some will gain. This happens in air or any other ...

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by mith
Wed Feb 11, 2009 9:30 pm
 
Forum: General Discussion
Topic: Electrons... To be or not to be...
Replies: 14
Views: 683

Re: Isolation of Mitochondria

... pellet rich in mithocondria (and chloroplasts if you are talking about plant cells.) Then, extract the mithochondria carefully with a syringe or a vacuum-pipe, and you should have the mithocondria pretty isolated.

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by hplc
Thu Jan 29, 2009 6:15 pm
 
Forum: Cell Biology
Topic: Isolation of Mitochondria
Replies: 2
Views: 553
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