Science desk | ||
---|---|---|
< March 19 | << Feb | March | Apr >> | March 21 > |
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. |
Can capacitors be controlled to discharge at a near constant voltage using some electrical circuitry apparatus? In other words, I'm asking if a capacitor can be used as a battery, and how a circuit could be/is constructed to do this.
Thanks, 74.173.90.59 ( talk) 00:28, 20 March 2008 (UTC) Sam
Ultracapacitors with carbon nanotubes covering plate surfaces to increase surface area may in the future replace common dry-cell batteries. Mac Davis ( talk) 03:16, 20 March 2008 (UTC)
Just got back from the doctor who told me something that has left me in a bit of shock. In America where there are ample medications to treat TB vaccines are not given as in some parts of Europe, Asia and Africa where the reverse is the case. The reason is that once a person is immunized against TB they develop antibodies, the problem being that the test for TB is based on whether or not a person has the antibodies. In America people are not immunized so they can serve as indicators of an epidemic. Does this mean that in America as far as the government or health care system is concerned the it is better that the population serve as human Guinea pigs than to be immunized against a disease despite the fact that almost no one in America would be immunized against TB in the event of a major catastrophe like nuclear war, followed by bombardment with biological weapons? —Preceding unsigned comment added by 71.100.10.177 ( talk • contribs)
Worrying about whether TB would be a problem in the wake of a nuclear exchange seems, to me, to be akin to worrying about how the problem of racial prejudice would be affected after an impact event. Yes, we can dream up all sorts of mad scientist situations but if there isn't a good reason to believe them plausible (or the most effective way for anyone to get what they want) it's not worth the resources to worry about them, much less act upon those resources. There are far more effective agents for use as biological weapons than TB; if we are talking about an enemy that can start nuclear war (and would?), I'm sure they could do far worse. -- Captain Ref Desk ( talk) 16:57, 20 March 2008 (UTC)
Isn't it strange that you can find foxes in Glasgow and London but not in Newcastle? Mr.K. (talk) 03:26, 20 March 2008 (UTC)
how can i make a sound transducer by myself in home?actually i want to make a switch which can be turned on by the sound of clapping .
The functions and are said to be orthogonal on interval if their inner product is zero
(1) |
For complex-valued functions or kets and , they are said to be orthogonal on interval when
(2) |
To continue my last discusstion, Quantum Mechanics: Entangled Wave Function, my question is how to prove the orthogonality of the Dirac delta function mathematically? Or some related resource? Thanks! - Justin545 ( talk) 08:53, 20 March 2008 (UTC)
The current commercial FM waveband is 88-108 MHz. However, I am trying to discover exactly when this spread came about.
I have a number of radio receivers, the dials on each differing significantly. One, an American set, covers 90-108Mhz. Two others, both British, cover 88-101 and 88-104 Mhz respectively. I have, however, been unable to ascertain when the full spectrum (88-108) came into use. Can anybody help?
Samilong ( talk) 10:29, 20 March 2008 (UTC)samilong
What is the connection between the intrinsic spin of quote-unquote elementary particles and the imaginary operator(s) defining complex numbers (and their further generalisations)? Intuitively, it seems they ought to be reasonably closely related, but this does not appear to be reflected in the "popular" literature. (One supposes that this intuitive sense could be ellaborated upon, if really necessary, but does not feel that it ought, as the connection is expected to be known, if not superficially evident.) 153.1.253.5 ( talk) 13:53, 20 March 2008 (UTC)
We haven't had a gull themed question in a while so here goes. Some local species of gull tap their feet onto the ground. My guess is it's either some strange courtship ritual or perhaps a method to draw insects out of the ground (I only see them do this on grassy fields). What do you guys think? PvT ( talk) 14:11, 20 March 2008 (UTC)
What the gulls are doing is something like (or actually is) worm charming and it's likely passed on down the generations carefully from gull to gull so that this skill won't die out. Julia Rossi ( talk) 11:52, 21 March 2008 (UTC)
I'm vagually sure I remember reading about this phenomenon (see subject line) a while ago, but I can't find any references to it now. Is this a recognized type of hallucination? Is there a word for it? How common is it? -- 86.135.178.19 ( talk) 20:40, 20 March 2008 (UTC)
How half-life work on individual atoms? If I have 8 atoms of substance X, which has a half life of 5s, then after 5s, I obviously have 4 atoms of X, plus whatever it decayed into and some radiation, right? So what if I have 1 atom of X? Is there a 50% chance that it will decay after 5s? If so, is that true for each atom in my 8 atom sample, i.e. that after 5s, there is a remote possibility that all of the atoms will have decayed, or that none of them will have? I'm very confused. 72.155.207.33 ( talk) 22:31, 20 March 2008 (UTC)
So what determines what amount decays? 72.155.207.33 ( talk) 04:52, 21 March 2008 (UTC)
Note also that for radioactive decay, you are in the "spooky" "God ... play[s] dice with the universe" world of quantum mechanics, where you pretty much have to leave your intuition at the door. (In actuality, with one radioactive atom you can have the situation where it is both decayed and not decayed simultaneously. Just ask Schrödinger's cat.) -- 128.104.112.85 ( talk) 00:49, 22 March 2008 (UTC)
what is the scientific name for fucking the shit out of someone excuse my french (yes i mean sexually)
Where do I nominate questions for "best of the ref desks"? HYENASTE 16:31, 24 March 2008 (UTC)
Science desk | ||
---|---|---|
< March 19 | << Feb | March | Apr >> | March 21 > |
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. |
Can capacitors be controlled to discharge at a near constant voltage using some electrical circuitry apparatus? In other words, I'm asking if a capacitor can be used as a battery, and how a circuit could be/is constructed to do this.
Thanks, 74.173.90.59 ( talk) 00:28, 20 March 2008 (UTC) Sam
Ultracapacitors with carbon nanotubes covering plate surfaces to increase surface area may in the future replace common dry-cell batteries. Mac Davis ( talk) 03:16, 20 March 2008 (UTC)
Just got back from the doctor who told me something that has left me in a bit of shock. In America where there are ample medications to treat TB vaccines are not given as in some parts of Europe, Asia and Africa where the reverse is the case. The reason is that once a person is immunized against TB they develop antibodies, the problem being that the test for TB is based on whether or not a person has the antibodies. In America people are not immunized so they can serve as indicators of an epidemic. Does this mean that in America as far as the government or health care system is concerned the it is better that the population serve as human Guinea pigs than to be immunized against a disease despite the fact that almost no one in America would be immunized against TB in the event of a major catastrophe like nuclear war, followed by bombardment with biological weapons? —Preceding unsigned comment added by 71.100.10.177 ( talk • contribs)
Worrying about whether TB would be a problem in the wake of a nuclear exchange seems, to me, to be akin to worrying about how the problem of racial prejudice would be affected after an impact event. Yes, we can dream up all sorts of mad scientist situations but if there isn't a good reason to believe them plausible (or the most effective way for anyone to get what they want) it's not worth the resources to worry about them, much less act upon those resources. There are far more effective agents for use as biological weapons than TB; if we are talking about an enemy that can start nuclear war (and would?), I'm sure they could do far worse. -- Captain Ref Desk ( talk) 16:57, 20 March 2008 (UTC)
Isn't it strange that you can find foxes in Glasgow and London but not in Newcastle? Mr.K. (talk) 03:26, 20 March 2008 (UTC)
how can i make a sound transducer by myself in home?actually i want to make a switch which can be turned on by the sound of clapping .
The functions and are said to be orthogonal on interval if their inner product is zero
(1) |
For complex-valued functions or kets and , they are said to be orthogonal on interval when
(2) |
To continue my last discusstion, Quantum Mechanics: Entangled Wave Function, my question is how to prove the orthogonality of the Dirac delta function mathematically? Or some related resource? Thanks! - Justin545 ( talk) 08:53, 20 March 2008 (UTC)
The current commercial FM waveband is 88-108 MHz. However, I am trying to discover exactly when this spread came about.
I have a number of radio receivers, the dials on each differing significantly. One, an American set, covers 90-108Mhz. Two others, both British, cover 88-101 and 88-104 Mhz respectively. I have, however, been unable to ascertain when the full spectrum (88-108) came into use. Can anybody help?
Samilong ( talk) 10:29, 20 March 2008 (UTC)samilong
What is the connection between the intrinsic spin of quote-unquote elementary particles and the imaginary operator(s) defining complex numbers (and their further generalisations)? Intuitively, it seems they ought to be reasonably closely related, but this does not appear to be reflected in the "popular" literature. (One supposes that this intuitive sense could be ellaborated upon, if really necessary, but does not feel that it ought, as the connection is expected to be known, if not superficially evident.) 153.1.253.5 ( talk) 13:53, 20 March 2008 (UTC)
We haven't had a gull themed question in a while so here goes. Some local species of gull tap their feet onto the ground. My guess is it's either some strange courtship ritual or perhaps a method to draw insects out of the ground (I only see them do this on grassy fields). What do you guys think? PvT ( talk) 14:11, 20 March 2008 (UTC)
What the gulls are doing is something like (or actually is) worm charming and it's likely passed on down the generations carefully from gull to gull so that this skill won't die out. Julia Rossi ( talk) 11:52, 21 March 2008 (UTC)
I'm vagually sure I remember reading about this phenomenon (see subject line) a while ago, but I can't find any references to it now. Is this a recognized type of hallucination? Is there a word for it? How common is it? -- 86.135.178.19 ( talk) 20:40, 20 March 2008 (UTC)
How half-life work on individual atoms? If I have 8 atoms of substance X, which has a half life of 5s, then after 5s, I obviously have 4 atoms of X, plus whatever it decayed into and some radiation, right? So what if I have 1 atom of X? Is there a 50% chance that it will decay after 5s? If so, is that true for each atom in my 8 atom sample, i.e. that after 5s, there is a remote possibility that all of the atoms will have decayed, or that none of them will have? I'm very confused. 72.155.207.33 ( talk) 22:31, 20 March 2008 (UTC)
So what determines what amount decays? 72.155.207.33 ( talk) 04:52, 21 March 2008 (UTC)
Note also that for radioactive decay, you are in the "spooky" "God ... play[s] dice with the universe" world of quantum mechanics, where you pretty much have to leave your intuition at the door. (In actuality, with one radioactive atom you can have the situation where it is both decayed and not decayed simultaneously. Just ask Schrödinger's cat.) -- 128.104.112.85 ( talk) 00:49, 22 March 2008 (UTC)
what is the scientific name for fucking the shit out of someone excuse my french (yes i mean sexually)
Where do I nominate questions for "best of the ref desks"? HYENASTE 16:31, 24 March 2008 (UTC)