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Why does cyclohexane smell like acetone? -- 70.244.234.128 ( talk) 00:49, 10 March 2011 (UTC)
I've read the articals here on fuel saving devices and understand that there is limited to no evidence of the value of the devices or the claims made by manufacturers. It appears that virtually all fuel saving devices are either additive based or impact the air flow and fuel mixture. However, I came across this ( http://www.gfchips.com/fordf150.aspx) device that uses a computer chip to improve fuel economy, etc. Is there any validity to this company's approach (especially given the old adadage: if it sounds too good to be true, it probably is . . .")? 99.250.117.26 ( talk) 01:14, 10 March 2011 (UTC)
Hi there. Not really a _science_ question, but does anyone happen to know the theoretical ratio between the channel power (1.23 MHz bandwidth) and the RMS power for a cdma2000 SR1 signal? 80.254.147.84 ( talk) 02:11, 10 March 2011 (UTC)
CDMA-2000 is pretty spectrum-filling, so I would "assume" for theoretical purposes that the spectrum is "flat" across the entire channel, and has a specified 3-dB frequency (or specified frequency rolloff rate). Since the signal is a digital QAM constellation with ~64 elements, it is actually pretty nasty when viewed as a pure frequency-spectrum; "theoretically" you should have 64 perfect frequency spikes; but as you of course know, the practical reality is that you have a fuzzy signal whose frequency-spread is determined by your QAM circuit's phase-noise specification. I doubt there's any use to construct a "thorough" theoretical model of the channel power - can you measure it? Otherwise, I'd report the channel power in watts per hertz (or mW/MHz, or other convenient unit), by "assuming" total RMS signal power divided by bandwidth; and spend some time spec`ing the out-of-band frequency rolloff to clean up my estimate. Two app-notes I found on the web search: Linear's AN99 LT5528 WCDMA ACPR, AltCPR and Noise Measurements discussing practical details for measurement; and Tektronix Digital Modulation technical series, Measuring ACPR of W-CDMA Signals with a Spectrum Analyzer. Don't underestimate the power of vendor app-notes - no matter how specific your need, you can probably search the major spectrum-analyzer manufacturers' public libraries, and if you've bought their equipment, you may be able to phone one of their engineers to discuss horrible engineering details with an experienced person. Nimur ( talk) 16:46, 10 March 2011 (UTC)
would entanglement support the conclusion that given two entangled particles at some large distance apart, if one of the particles were to somehow cease to exist that the other would simultaneously cease to exist? —Preceding unsigned comment added by 98.221.254.154 ( talk) 05:03, 10 March 2011 (UTC)
I thought one of them could be annihilated with antiparticle?? —Preceding unsigned comment added by 165.212.189.187 ( talk) 18:32, 10 March 2011 (UTC)
"Since energy and momentum must be conserved, the particles are not actually made into nothing, but rather into new particles. Antiparticles have exactly opposite additive quantum numbers from particles, so the sums of all quantum numbers of the original pair are zero." OK, So one particle could be made into new particles while the other might not be? —Preceding unsigned comment added by 165.212.189.187 ( talk) 19:06, 10 March 2011 (UTC)
Yes or no, can one decay and not the other? —Preceding unsigned comment added by 98.221.254.154 ( talk) 00:41, 11 March 2011 (UTC)
Sorry, so there could be more than one "particle" in an entangled "pair"? 98.221.254.154 ( talk) 01:47, 11 March 2011 (UTC)
Is every particle in our galaxy entangled with every other one? —Preceding unsigned comment added by 165.212.189.187 ( talk) 14:41, 11 March 2011 (UTC)
What is the right way of presentation "Myasthenic crisis" or "Myasthenia Crisis"? aniketnik 10:06, 10 March 2011 (UTC) — Preceding unsigned comment added by Aniketnik ( talk • contribs)
Hello. When I wake up in the morning, I have a cold sensation that usually lasts an hour or more. When I mentioned about this to a friend, he said he has experienced the same, and it's related to having a metabolism that effieciently converts extra energy into heat, and that this is probably why we're both thin while we eat a lot and don't get much exercise. Could this be the case? 212.68.15.66 ( talk) 10:09, 10 March 2011 (UTC)
Global Warming will cause sea level rise. This will have some effect on the tidal friction the Moon experiences, causing the rate at which it recedes from the Earth to change a bit. Will this rate increase or decrease? Count Iblis ( talk) 15:02, 10 March 2011 (UTC)
Hmmm, wouldn't the change in total lengths of coast lines be a factor here, as this ultimately provides for the friction that moves the tidal bulge ahead of the Moon? It seems to me that this could change quite dramatically if e.g. all the ice on Antarctica were to melt, but I'm still not sure if this woild increase or decrease the recession rate. Count Iblis ( talk) 15:28, 12 March 2011 (UTC)
In a chemical catalog item description, what is the meaning of something like (N/10)? For example, "Hydrocholric acid solution, 0.1N (N/10)". I am looking specifically at Cole Parmer and I've been unable to find any explanation in their information. ike9898 ( talk) 16:56, 10 March 2011 (UTC)
I need to prepare a 100ml solution of NaOH at 40% m/m (in water). As NaOH absorbs the humidity in air, I have consulted an old Handbook, section sodium hydroxyde, concentration properties of, in varying concentrations but I am still unsure as to how much NaOH (in grams) I need. Please help.
Thank you very much. -- 192.197.51.41 ( talk) 18:06, 10 March 2011 (UTC)
I was wondering whether photocopier ink or laser-printer ink contains any metallic substances or metal compounds?
Thanks. 71.252.113.85 ( talk) 20:37, 10 March 2011 (UTC)
Would the probability cloud of a free electron look the same as an electron in the ground state bound to a hydrogen atom? ScienceApe ( talk) 20:40, 10 March 2011 (UTC)
Without a nucleus to bind the cloud, the autorepulsion will cause the cloud formation to disolve. Plasmic Physics ( talk) 22:41, 10 March 2011 (UTC)
will we ever know for sure what is inside of the earth or if it is hollow will we ever know for sure what causes the earth's magnetic field — Preceding unsigned comment added by Lufc88 ( talk • contribs) 21:41, 10 March 2011 (UTC)
how can we prove that it is the dynamo effect any ideas — Preceding unsigned comment added by Lufc88 ( talk • contribs) 22:49, 11 March 2011 (UTC)
Science desk | ||
---|---|---|
< March 9 | << Feb | March | Apr >> | March 11 > |
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. |
Why does cyclohexane smell like acetone? -- 70.244.234.128 ( talk) 00:49, 10 March 2011 (UTC)
I've read the articals here on fuel saving devices and understand that there is limited to no evidence of the value of the devices or the claims made by manufacturers. It appears that virtually all fuel saving devices are either additive based or impact the air flow and fuel mixture. However, I came across this ( http://www.gfchips.com/fordf150.aspx) device that uses a computer chip to improve fuel economy, etc. Is there any validity to this company's approach (especially given the old adadage: if it sounds too good to be true, it probably is . . .")? 99.250.117.26 ( talk) 01:14, 10 March 2011 (UTC)
Hi there. Not really a _science_ question, but does anyone happen to know the theoretical ratio between the channel power (1.23 MHz bandwidth) and the RMS power for a cdma2000 SR1 signal? 80.254.147.84 ( talk) 02:11, 10 March 2011 (UTC)
CDMA-2000 is pretty spectrum-filling, so I would "assume" for theoretical purposes that the spectrum is "flat" across the entire channel, and has a specified 3-dB frequency (or specified frequency rolloff rate). Since the signal is a digital QAM constellation with ~64 elements, it is actually pretty nasty when viewed as a pure frequency-spectrum; "theoretically" you should have 64 perfect frequency spikes; but as you of course know, the practical reality is that you have a fuzzy signal whose frequency-spread is determined by your QAM circuit's phase-noise specification. I doubt there's any use to construct a "thorough" theoretical model of the channel power - can you measure it? Otherwise, I'd report the channel power in watts per hertz (or mW/MHz, or other convenient unit), by "assuming" total RMS signal power divided by bandwidth; and spend some time spec`ing the out-of-band frequency rolloff to clean up my estimate. Two app-notes I found on the web search: Linear's AN99 LT5528 WCDMA ACPR, AltCPR and Noise Measurements discussing practical details for measurement; and Tektronix Digital Modulation technical series, Measuring ACPR of W-CDMA Signals with a Spectrum Analyzer. Don't underestimate the power of vendor app-notes - no matter how specific your need, you can probably search the major spectrum-analyzer manufacturers' public libraries, and if you've bought their equipment, you may be able to phone one of their engineers to discuss horrible engineering details with an experienced person. Nimur ( talk) 16:46, 10 March 2011 (UTC)
would entanglement support the conclusion that given two entangled particles at some large distance apart, if one of the particles were to somehow cease to exist that the other would simultaneously cease to exist? —Preceding unsigned comment added by 98.221.254.154 ( talk) 05:03, 10 March 2011 (UTC)
I thought one of them could be annihilated with antiparticle?? —Preceding unsigned comment added by 165.212.189.187 ( talk) 18:32, 10 March 2011 (UTC)
"Since energy and momentum must be conserved, the particles are not actually made into nothing, but rather into new particles. Antiparticles have exactly opposite additive quantum numbers from particles, so the sums of all quantum numbers of the original pair are zero." OK, So one particle could be made into new particles while the other might not be? —Preceding unsigned comment added by 165.212.189.187 ( talk) 19:06, 10 March 2011 (UTC)
Yes or no, can one decay and not the other? —Preceding unsigned comment added by 98.221.254.154 ( talk) 00:41, 11 March 2011 (UTC)
Sorry, so there could be more than one "particle" in an entangled "pair"? 98.221.254.154 ( talk) 01:47, 11 March 2011 (UTC)
Is every particle in our galaxy entangled with every other one? —Preceding unsigned comment added by 165.212.189.187 ( talk) 14:41, 11 March 2011 (UTC)
What is the right way of presentation "Myasthenic crisis" or "Myasthenia Crisis"? aniketnik 10:06, 10 March 2011 (UTC) — Preceding unsigned comment added by Aniketnik ( talk • contribs)
Hello. When I wake up in the morning, I have a cold sensation that usually lasts an hour or more. When I mentioned about this to a friend, he said he has experienced the same, and it's related to having a metabolism that effieciently converts extra energy into heat, and that this is probably why we're both thin while we eat a lot and don't get much exercise. Could this be the case? 212.68.15.66 ( talk) 10:09, 10 March 2011 (UTC)
Global Warming will cause sea level rise. This will have some effect on the tidal friction the Moon experiences, causing the rate at which it recedes from the Earth to change a bit. Will this rate increase or decrease? Count Iblis ( talk) 15:02, 10 March 2011 (UTC)
Hmmm, wouldn't the change in total lengths of coast lines be a factor here, as this ultimately provides for the friction that moves the tidal bulge ahead of the Moon? It seems to me that this could change quite dramatically if e.g. all the ice on Antarctica were to melt, but I'm still not sure if this woild increase or decrease the recession rate. Count Iblis ( talk) 15:28, 12 March 2011 (UTC)
In a chemical catalog item description, what is the meaning of something like (N/10)? For example, "Hydrocholric acid solution, 0.1N (N/10)". I am looking specifically at Cole Parmer and I've been unable to find any explanation in their information. ike9898 ( talk) 16:56, 10 March 2011 (UTC)
I need to prepare a 100ml solution of NaOH at 40% m/m (in water). As NaOH absorbs the humidity in air, I have consulted an old Handbook, section sodium hydroxyde, concentration properties of, in varying concentrations but I am still unsure as to how much NaOH (in grams) I need. Please help.
Thank you very much. -- 192.197.51.41 ( talk) 18:06, 10 March 2011 (UTC)
I was wondering whether photocopier ink or laser-printer ink contains any metallic substances or metal compounds?
Thanks. 71.252.113.85 ( talk) 20:37, 10 March 2011 (UTC)
Would the probability cloud of a free electron look the same as an electron in the ground state bound to a hydrogen atom? ScienceApe ( talk) 20:40, 10 March 2011 (UTC)
Without a nucleus to bind the cloud, the autorepulsion will cause the cloud formation to disolve. Plasmic Physics ( talk) 22:41, 10 March 2011 (UTC)
will we ever know for sure what is inside of the earth or if it is hollow will we ever know for sure what causes the earth's magnetic field — Preceding unsigned comment added by Lufc88 ( talk • contribs) 21:41, 10 March 2011 (UTC)
how can we prove that it is the dynamo effect any ideas — Preceding unsigned comment added by Lufc88 ( talk • contribs) 22:49, 11 March 2011 (UTC)