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I'm reading now in a textbook that "Cell bodies are located in the gray matter of the CNS, and their collections are called ganglia in the PNS and nuclei in the CNS." Does it say that the gray matter of CNS is just collection of the bodies and the white matter is the collection of the Dendrites? If it is, what is the reason for the grey color of the bodies? is it because of that the bodies have nuclei? 93.126.95.68 ( talk) 00:06, 24 March 2016 (UTC)
93.126.95.68 ( talk) 01:35, 24 March 2016 (UTC)
In the article on Specific impulse. It specifies that "If mass (kilogram or slug) is used as the unit of propellant, then specific impulse has units of velocity." this statement may be correct. But! "If weight (newton or pound) is used instead, then specific impulse has units of time (seconds).". Weight is supposed to have unit in mass not force? I suspect there's some serious mixup here. Anyone care to scrutinize this from a physics standpoint ? Ferrofield ( talk) 04:01, 24 March 2016 (UTC)
Wouldn't "If force (newton or pound-force) is used instead, then the specific impulse has units of time (seconds)." be more correct? Currently it seems to use weight as a substitute for force and a lot of loosely specified imperial units. Ferrofield ( talk) 02:21, 26 March 2016 (UTC)
A black hole event horizon is supposed to be the final end of interaction of anything falling into it with the outside world, besides hawking radiation and preservation of information. Now suppose the gravity exerted by the black hole is measured externally and an object less massive than the black hole falls into it. Will the gravity of the black hole plus an object outside of it become less in magnitude when the external objects falls into it? Such that the event horizon has the ability to chop gravitational interaction? Ferrofield ( talk) 05:06, 24 March 2016 (UTC)
Can egg white be whipped into a foam if it already contains sugar and cocoa powder or will these prevent that? ---- Seans Potato Business 07:59, 24 March 2016 (UTC)
Question | Remark |
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In this source [exergy.se/ftp/exergetics.pdf, pages 70-77] author writes:
Assume a system of N unique particles. The number of allowed states Ω of the system is exponentially depending on N. Let the probability of the j:th state be Pj and the sum of the probabilities of all states to be 1, i.e. the system is in at least one state
The entropy of the system is then defined from statistical mechanics as
... Let us exemplify by a system of N different particles with 2 possible states each, e.g. 0 or 1. Then we have . If there are no other restrictions then all must be , see the Table below. Is it correct? We know form Boltzmann's entropy formula that , where . Taking the logarithm of W, we have . Applying Stirling’s theorem, we obtain
. Let . Then
and . So first, we must add factor (BTW in wiki articles also is absent). Second, is a number of existing states among all particles, not all possible states. So we count only system states, which consist of same set of particle states. E.g. we have 5 particles of which 2 are in state 0 and 3 are in 1. E.g. we have system 00111. Now we can consider only 00111, 01011, 01101, 01110, 10011, 10101, 10110, 11001, 11010, 11100. We cannot compose 00000 or 11111. In this example we have So why author believes and counts ??? Is it correct? |
Boltzmann's entropy formula
[ http://exergy.se/ftp/exergetics.pdf , pages 70-77]
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37.53.37.94 ( talk) 20:07, 24 March 2016 (UTC)
Question | Remark |
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And 2nd question. Can human generate information (and so energy) by brain activity: thinking and processing? For me it's important to distinguish both these types of activity. I know that from knowledge of particles' speed we can generate energy (Maxwell demon). But it is not brain activity, but measurements. And I also know brain is processing huge amount of data. But I feel brain does the job only for own purposes (human survival). If we are talking about processing, then decoding also is present. So we can use Shannon information. But I can't assemble the puzzle.
Brain decodes information (e.g. from eyes) and then answers. To minimize processing it can use instincts, learning (it's much harder as connected with statistics collection to estimate probabilities). If neither instincts nor learned patterns fit, then brain thinks. |
37.53.37.94 ( talk) 21:12, 24 March 2016 (UTC)
Science desk | ||
---|---|---|
< March 23 | << Feb | March | Apr >> | March 25 > |
Welcome to the Wikipedia Science Reference Desk Archives |
---|
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages. |
I'm reading now in a textbook that "Cell bodies are located in the gray matter of the CNS, and their collections are called ganglia in the PNS and nuclei in the CNS." Does it say that the gray matter of CNS is just collection of the bodies and the white matter is the collection of the Dendrites? If it is, what is the reason for the grey color of the bodies? is it because of that the bodies have nuclei? 93.126.95.68 ( talk) 00:06, 24 March 2016 (UTC)
93.126.95.68 ( talk) 01:35, 24 March 2016 (UTC)
In the article on Specific impulse. It specifies that "If mass (kilogram or slug) is used as the unit of propellant, then specific impulse has units of velocity." this statement may be correct. But! "If weight (newton or pound) is used instead, then specific impulse has units of time (seconds).". Weight is supposed to have unit in mass not force? I suspect there's some serious mixup here. Anyone care to scrutinize this from a physics standpoint ? Ferrofield ( talk) 04:01, 24 March 2016 (UTC)
Wouldn't "If force (newton or pound-force) is used instead, then the specific impulse has units of time (seconds)." be more correct? Currently it seems to use weight as a substitute for force and a lot of loosely specified imperial units. Ferrofield ( talk) 02:21, 26 March 2016 (UTC)
A black hole event horizon is supposed to be the final end of interaction of anything falling into it with the outside world, besides hawking radiation and preservation of information. Now suppose the gravity exerted by the black hole is measured externally and an object less massive than the black hole falls into it. Will the gravity of the black hole plus an object outside of it become less in magnitude when the external objects falls into it? Such that the event horizon has the ability to chop gravitational interaction? Ferrofield ( talk) 05:06, 24 March 2016 (UTC)
Can egg white be whipped into a foam if it already contains sugar and cocoa powder or will these prevent that? ---- Seans Potato Business 07:59, 24 March 2016 (UTC)
Question | Remark |
---|---|
In this source [exergy.se/ftp/exergetics.pdf, pages 70-77] author writes:
Assume a system of N unique particles. The number of allowed states Ω of the system is exponentially depending on N. Let the probability of the j:th state be Pj and the sum of the probabilities of all states to be 1, i.e. the system is in at least one state
The entropy of the system is then defined from statistical mechanics as
... Let us exemplify by a system of N different particles with 2 possible states each, e.g. 0 or 1. Then we have . If there are no other restrictions then all must be , see the Table below. Is it correct? We know form Boltzmann's entropy formula that , where . Taking the logarithm of W, we have . Applying Stirling’s theorem, we obtain
. Let . Then
and . So first, we must add factor (BTW in wiki articles also is absent). Second, is a number of existing states among all particles, not all possible states. So we count only system states, which consist of same set of particle states. E.g. we have 5 particles of which 2 are in state 0 and 3 are in 1. E.g. we have system 00111. Now we can consider only 00111, 01011, 01101, 01110, 10011, 10101, 10110, 11001, 11010, 11100. We cannot compose 00000 or 11111. In this example we have So why author believes and counts ??? Is it correct? |
Boltzmann's entropy formula
[ http://exergy.se/ftp/exergetics.pdf , pages 70-77]
|
37.53.37.94 ( talk) 20:07, 24 March 2016 (UTC)
Question | Remark |
---|---|
And 2nd question. Can human generate information (and so energy) by brain activity: thinking and processing? For me it's important to distinguish both these types of activity. I know that from knowledge of particles' speed we can generate energy (Maxwell demon). But it is not brain activity, but measurements. And I also know brain is processing huge amount of data. But I feel brain does the job only for own purposes (human survival). If we are talking about processing, then decoding also is present. So we can use Shannon information. But I can't assemble the puzzle.
Brain decodes information (e.g. from eyes) and then answers. To minimize processing it can use instincts, learning (it's much harder as connected with statistics collection to estimate probabilities). If neither instincts nor learned patterns fit, then brain thinks. |
37.53.37.94 ( talk) 21:12, 24 March 2016 (UTC)