The sphere itself, no; you would use it in some experiments (carefully, to reduce error) for whatever purpose, and then you would put it back in the vault. However, once this Si sphere is complete they will know to some level of accuracy X how many Si atoms make up the sphere. That way this company can just create more spheres, count the number of Si atoms in it and as long as the interferometry matches the number of Si atoms they set as being 1kg to within their limits of measurement, then these other Si spheres can also be used to do the same experiments with the same level of accuracy and precision (two different things).
The key difference between these Si spheres and the hung of metal alloy in paris is that these spheres are reproduceable. You would have an incredibly hard time creating a hunk of metal alloy the exact same mass as that in Paris; furthermore, I presume these spheres are less susceptible to degradation due to environmental effects.
In essence, we're re-defining the kilogram so that instead of the formula 1kg=1(Hunk of Metal) we have 1kg=X(Si atoms), where X (my understanding, anyway) is what they are trying to determine as closely as possible. Once this standard is actually set, they will select an exact number of Si atoms in the middle of their error distribution and say "this is the definition for 1kg!", even if that means there's a tiny change in what 1kg really is, since the difference is so small that we wouldn't be able to tell there was one until years down the road when we have more accurate sensors to measure both mass and number of atoms. But even then, the number they chose wouldn't change.
Since the pole would be made of some type of matter, the time it took the person on the other end of the pole to notice that you had pushed it would be the length of the pole divided by the wave velocity of the material.
Force (in the traditional sense, as we're taking here) is passed by compression waves within the pole; this "information" travels down the pole in the form of compression waves, the velocity of which depends on the material you're using. A steel tube, for example, has a very high speed compared to air (note that this applies to solides, liquids and gases equally). Try this. Stand some distance apart from a friend with a steel tube (like the top of a fence or something) and put your ear against the tube. Have your friend bang the tube with a hammer. You'll hear the sound through the tube before you hear it through the air, but its still limit to the speed of compression.
As someone else replied, you would need a perfectly rigid body to trasmit signals in this way faster than light; however A) no such material is known to man and B) I am convinced some other force would intervene, preventing this case from occuring even if you could design a "perfectly rigid" material.
... but the first thing that I thought of was that here you have an app (Safari) that works perfectly fine on Macs; as soon as it gets ported to Windows, BAM, instantly full of vulnerabilities. Would Apple go so far as to break their own product to deface an opponent in the OS arena?
Except that with a radio station when someone phones in a request, everyone listening to that broadcast has to hear it. Often with internet radio each user will be listening to their own version of the 'broadcast', so if you send in a request then only you hear that song.
I haven't gotten around to reading this yet but it is definitely on my list. Just finished Consider Phlebas and the rest of the Ender saga, so as soon as I'm finished The Time Traveller's Wife I will get right on it.
If I were going to have my ashes sent into space, I'd want my own personal canister aboard a larger payload that gets launched out into space; as in, keeps on going and going and going forever, away from Earth (at least until I hit a planet or star or something). Maybe even a tiny ion engine to continually accelerate.
The title is misleading. The Cell processor is not a "console" chip, it is a microprocessor. Period. So what if Sony decided to use the Cell processor in the PS3? They could have selected from any number of processors: AMD64, x86, PPC, Motorola 6800.. whatever!
The Cell processor is and always has been designed for shipping out complex calculations to sub-processing units (I believe their latest term is Synergistic Processing Units [SPUs]?), it was not designed for purpose of Sony bragging about it.
In this case, Apple didn't even do it second; FastMac beat them to it. While this article is still pro-Mac, its more of an Apple bashing than praising.
If I'm not mistake, solid water isn't actually slipper in and of itself.. its the thin layer of liquid water we create whenever touching it and applying pressure. Look up curling.
Of course I'm open to enlightenment if I've got something wrong.
I can't tell you about schools in the UK, but I know for a fact that this scheme would not work here in Ontario. Universities keep an "unofficial" ranking of the academic standing of high-schools throughout the province. This doesn't mean "this school has a really high average!". This ranking takes into account subject focus and quality of education. For example, a high-school that has a large number of graduates with high averages that go on to study in Engineering, Medicine, Physics, Math etc. are given a high rating for academic subjects. Schools with a large number of graduates that go on to study Music, Literature, Art, etc. are given a high rating for the Arts.
You could almost think of this as a normalizing factor (I like to call it alpha). They multiply each student's graduating average by their school's alpha, and it is this normalized result that they use to rank students for acceptance.
O_o....... If you despise vendor lock-in, then don't get locked in; if you choose to buy a car stereo with an iPod dock connector, that's your prerogative. If the Zune could overcome 1, 2 and 3, wouldn't you consider buying a car stereo with a Zune dock connector instead? Imaginary lock-ins that don't yet exist and are up to consumer choice cannot be touted as requirements for competing products.
I'm not going to run around complaining that I'm not going to buy Windows Vista because it doesn't work on my PPC Macbook; what you're proposing is that everyone lie down and accept Apple's lock-in, instead of fighting back and getting NO lock-in.. there is a big difference.
Just like when Firefox turns your address bar yellow when you're visiting a "secure" website? Sure, the website may be secured, but is it secured to the servers you think you're accessing? You still have to be careful to make sure you're at the right place.. just because a website has SSL enabled with a valid certificate doesn't mean they are going to play nicely with all the data you type into their forms.
Kind of a weird guy, but pretty cool to have as a comp prof back in first year =P After a couple weeks we hardly even noticed his gear anymore, and if friends saw him and freaked out going "what's that?!", it took us a few seconds to realize what they were talking about.
I payed $50 for an FM transmitter that lets me listen to my iPod on my car stereo. There is quality degradation (though reception is pretty good with the model I bought), and the audio loses a bit of definition in the high- and low-frequency ranges. Clearly, I am only listening to this music as the artist "sort-of intend(ed) it." However, I had the option to spend about $200 and install a new car stereo that would let me plug my iPod directly into it with a digital cable. This is a price hike without which I cannot listen to the music "as intend(ed)!"
I chose to spend $50 and live with some signal loss rather than spend >$200 for a nicer-sounding system. Users have the choice to spend less for lower-quality versions if they want, or they can spend more for higher quality versions. $0.30 is hardly prohibiting, if you're buying music in bulk off of iTMS anyway. Some people would rather pay less and get less, for whatever reason, and that's their choice.
I do, however, agree with your statement that this is not as large a victory as some would think.. from my understanding they aren't selling high-quality MP3s, they are selling high-quality AAC files; sure, my iPod will play them, but my iRiver won't.. neither will my sister's Rio or any other number of portable music players out there.
Hmm.. I suppose it is a bit ambiguous where you draw the line between what is the "engine" and what is the "propulsor".. I tend to think of the entire drive-train (from powerplant to vehicle-medium transmission) to be lumped into the "engine" of the vehicle, but other views may differ. As for your analogy to an old river boat, I do not think that it is quite suited to this discussion. As far as I'm aware, the classical definition of a jet implies that the fluid effluent is under pressure, resulting in a coherent stream of the fluid through the medium (regardless of whether that medium is the same material as the fluid stream or not). In your example of paddle wheels, there is no stream of fluid propelled rearward. Sure there is a net momentum change, but the affected fluid particles are quickly absorbed back into the surrounding medium; in other words, the momentum imparted on these molecules is relatively small compared to the viscosity of the fluid.
In a jet stream, however, the net momentum imparted on the fluid particles is very high with respect to the fluid viscosity, resulting in a stream that persists far down-stream of the jet nozzle (which, if you want to get technical, I believe might be part of the definition of a jet.. not sure if you can have a practical jet without a fluid nozzle?). This can often be several times the length of the craft itself, as is the case with Sea-doos and, I believe, most turbofan/turbojet aircraft. The large difference in velocity/momentum between the jet and the medium prevents the re-absorbtion of the stream; you get boundary layers and vortices at the interface, but those effects dont' become noticeable until you are far down-stream of the jet nozzle.
I guess what I was trying to point out is that alot of the time we tend to think of a "jet engine" (or turbfan/turbojet engine) as being all one unit, while something like in a Sea-doo is entirely separate; ultimately, while the powerplants of "turbine engines" and pump-jet engines may differ, the basic concept in the sense of "they produce a jet of fluid to propel the craft" stays the same.
At this point though I would say we're getting pretty close to tomayto/tomahto;)
Your analogy is faulty; if you indeed look at "the nice picture" in the article you linked, you'll notice that the combustion actually takes place in the combustion chamber, between the compressor and turbine stages; the exhaust stream is produced as a result of this combustion. Furthermore, the article you linked to was for a turbojet engine, which is nothing but a sub-class of the jet engine.
A jet engine does not specify that the energy source must be an internal combustion engine; it only specifies that thrust is generated in one direction by expelling a fluid (usually air/exhaust or water) in the opposite direction. Having said that, most common jet engines do use internal combustion. It is simply a matter of type.
A common example of a jet engine that uses a reciprocating internal combustion engine (typically two- or four-stroke) for power can be found in Sea-Doos, where a standard reciprocating internal combustion engine (like you would find in most automobiles) is used to drive an impeller that expels a jet of high-pressure water rearward of the craft, propelling the craft forward.
A common example of a jet engine that uses a continuous flow internal combustion engine is a turbojet engine, commonly found on military aircraft, or turbofan engine, commonly found on commercial passenger aircraft. Both turbojet and turbofan engines share a similar design in that the incoming air is pressurized using a compressor, mixed with fuel and combusted in the combustion chamber, and then expelled rearward of the craft for thrust. In this exhaust stream you will find a gas turbine that is used to power the compressor. In the case of turbofan engines, this gas turbine will also power a large fan located at the engine intake, which is where the majority of the thrust in a standard commercial jet-engine comes from.
The important thing to note is that reciprocating and continuous flow engines are both types of internal combustion engines; the public is just used to thinking of the ICE as a two- or four-stroke cycle system using pistons and a crankshaft, which is just not true. The combustion chamber in a turbojet or turbofan (or turboprop, now that I think about it) engine is still a confined-space combustion chamber used to burn air mixed with fuel at high pressures.
While I'm sure that looking at pretty pictures helps grade-schoolers learn "the way of things", typically it is considered good practice to read up on a subject before putting someone else down about not understanding it.
And in case you were wondering, I am a 4th year Aerospace Engineering student at the University of Toronto. While I don't claim to know everything there is to know in the world of combustion engines, I have had a fair amount of exposure both from private study and from experts and researchers in the field.
Aikon-
p.s. No, Wikipedia is not a reference I would ever cite in a research paper, though in this area its information is pretty good. I link to it only because it offers a great overall explanation of the processes involved. If you are sufficiently interested I suspect you will be able to get your hands on some real study material that goes into much more detail.
Not to mention bandwidth savings! You could write a Slashdot client that needed to grab only an array of memecodes with a corresponding parameter matrix (likely sparse), and you could reproduce the entire Slashdot thread client-side!
Aikon-
Slashdot Mirror
The sphere itself, no; you would use it in some experiments (carefully, to reduce error) for whatever purpose, and then you would put it back in the vault. However, once this Si sphere is complete they will know to some level of accuracy X how many Si atoms make up the sphere. That way this company can just create more spheres, count the number of Si atoms in it and as long as the interferometry matches the number of Si atoms they set as being 1kg to within their limits of measurement, then these other Si spheres can also be used to do the same experiments with the same level of accuracy and precision (two different things).
The key difference between these Si spheres and the hung of metal alloy in paris is that these spheres are reproduceable. You would have an incredibly hard time creating a hunk of metal alloy the exact same mass as that in Paris; furthermore, I presume these spheres are less susceptible to degradation due to environmental effects.
In essence, we're re-defining the kilogram so that instead of the formula 1kg=1(Hunk of Metal) we have 1kg=X(Si atoms), where X (my understanding, anyway) is what they are trying to determine as closely as possible. Once this standard is actually set, they will select an exact number of Si atoms in the middle of their error distribution and say "this is the definition for 1kg!", even if that means there's a tiny change in what 1kg really is, since the difference is so small that we wouldn't be able to tell there was one until years down the road when we have more accurate sensors to measure both mass and number of atoms. But even then, the number they chose wouldn't change.
Aikon-
Since the pole would be made of some type of matter, the time it took the person on the other end of the pole to notice that you had pushed it would be the length of the pole divided by the wave velocity of the material.
Force (in the traditional sense, as we're taking here) is passed by compression waves within the pole; this "information" travels down the pole in the form of compression waves, the velocity of which depends on the material you're using. A steel tube, for example, has a very high speed compared to air (note that this applies to solides, liquids and gases equally). Try this. Stand some distance apart from a friend with a steel tube (like the top of a fence or something) and put your ear against the tube. Have your friend bang the tube with a hammer. You'll hear the sound through the tube before you hear it through the air, but its still limit to the speed of compression.
As someone else replied, you would need a perfectly rigid body to trasmit signals in this way faster than light; however A) no such material is known to man and B) I am convinced some other force would intervene, preventing this case from occuring even if you could design a "perfectly rigid" material.
Aikon-
... but the first thing that I thought of was that here you have an app (Safari) that works perfectly fine on Macs; as soon as it gets ported to Windows, BAM, instantly full of vulnerabilities. Would Apple go so far as to break their own product to deface an opponent in the OS arena?
Aikon-
If you can't blindly trust your word processor's spelling checker, how on Earth could you think you could blindly trust a GPS system?
Aikon-
Except that with a radio station when someone phones in a request, everyone listening to that broadcast has to hear it. Often with internet radio each user will be listening to their own version of the 'broadcast', so if you send in a request then only you hear that song.
Aikon-
I haven't gotten around to reading this yet but it is definitely on my list. Just finished Consider Phlebas and the rest of the Ender saga, so as soon as I'm finished The Time Traveller's Wife I will get right on it.
Thanks,
-Aikon
If I were going to have my ashes sent into space, I'd want my own personal canister aboard a larger payload that gets launched out into space; as in, keeps on going and going and going forever, away from Earth (at least until I hit a planet or star or something). Maybe even a tiny ion engine to continually accelerate.
Aikon-
The title is misleading. The Cell processor is not a "console" chip, it is a microprocessor. Period. So what if Sony decided to use the Cell processor in the PS3? They could have selected from any number of processors: AMD64, x86, PPC, Motorola 6800.. whatever!
The Cell processor is and always has been designed for shipping out complex calculations to sub-processing units (I believe their latest term is Synergistic Processing Units [SPUs]?), it was not designed for purpose of Sony bragging about it.
Aikon-
In this case, Apple didn't even do it second; FastMac beat them to it. While this article is still pro-Mac, its more of an Apple bashing than praising.
Aikon-
I'm pretty sure the point of the article was that this is a Blu-Ray drive for Macs, not PCs. We know there are PC drives already.
Could be wrong though O_o
Aikon-
And they're going to call this new commercial product: Yew Tubes !!
Thank you and goodnight.
Aikon-
If I'm not mistake, solid water isn't actually slipper in and of itself.. its the thin layer of liquid water we create whenever touching it and applying pressure. Look up curling.
Of course I'm open to enlightenment if I've got something wrong.
Aikon-
I can't tell you about schools in the UK, but I know for a fact that this scheme would not work here in Ontario. Universities keep an "unofficial" ranking of the academic standing of high-schools throughout the province. This doesn't mean "this school has a really high average!". This ranking takes into account subject focus and quality of education. For example, a high-school that has a large number of graduates with high averages that go on to study in Engineering, Medicine, Physics, Math etc. are given a high rating for academic subjects. Schools with a large number of graduates that go on to study Music, Literature, Art, etc. are given a high rating for the Arts.
You could almost think of this as a normalizing factor (I like to call it alpha). They multiply each student's graduating average by their school's alpha, and it is this normalized result that they use to rank students for acceptance.
Aikon-
SIXAXIS
Sony was.. right? /head explodes
Aikon-
My thoughts go out to to all those involved in this tragedy, their families, friends, and everyone else around the world that is shocked and apalled.
Aikon-
I, for one, would be extremely pissed off if my WoW packets suddenly started taking a back seat to Grandma's dancing Jesus GIF
Aikon-
O_o....... If you despise vendor lock-in, then don't get locked in; if you choose to buy a car stereo with an iPod dock connector, that's your prerogative. If the Zune could overcome 1, 2 and 3, wouldn't you consider buying a car stereo with a Zune dock connector instead? Imaginary lock-ins that don't yet exist and are up to consumer choice cannot be touted as requirements for competing products.
I'm not going to run around complaining that I'm not going to buy Windows Vista because it doesn't work on my PPC Macbook; what you're proposing is that everyone lie down and accept Apple's lock-in, instead of fighting back and getting NO lock-in.. there is a big difference.
Aikon-
Just like when Firefox turns your address bar yellow when you're visiting a "secure" website? Sure, the website may be secured, but is it secured to the servers you think you're accessing? You still have to be careful to make sure you're at the right place.. just because a website has SSL enabled with a valid certificate doesn't mean they are going to play nicely with all the data you type into their forms.
Aikon-
Kind of a weird guy, but pretty cool to have as a comp prof back in first year =P After a couple weeks we hardly even noticed his gear anymore, and if friends saw him and freaked out going "what's that?!", it took us a few seconds to realize what they were talking about.
Aikon-
Google says 100 mpg = 2.35 L/100km
Aikon-
I payed $50 for an FM transmitter that lets me listen to my iPod on my car stereo. There is quality degradation (though reception is pretty good with the model I bought), and the audio loses a bit of definition in the high- and low-frequency ranges. Clearly, I am only listening to this music as the artist "sort-of intend(ed) it." However, I had the option to spend about $200 and install a new car stereo that would let me plug my iPod directly into it with a digital cable. This is a price hike without which I cannot listen to the music "as intend(ed)!"
I chose to spend $50 and live with some signal loss rather than spend >$200 for a nicer-sounding system. Users have the choice to spend less for lower-quality versions if they want, or they can spend more for higher quality versions. $0.30 is hardly prohibiting, if you're buying music in bulk off of iTMS anyway. Some people would rather pay less and get less, for whatever reason, and that's their choice.
I do, however, agree with your statement that this is not as large a victory as some would think.. from my understanding they aren't selling high-quality MP3s, they are selling high-quality AAC files; sure, my iPod will play them, but my iRiver won't.. neither will my sister's Rio or any other number of portable music players out there.
Aikon-
Hmm.. I suppose it is a bit ambiguous where you draw the line between what is the "engine" and what is the "propulsor".. I tend to think of the entire drive-train (from powerplant to vehicle-medium transmission) to be lumped into the "engine" of the vehicle, but other views may differ. As for your analogy to an old river boat, I do not think that it is quite suited to this discussion. As far as I'm aware, the classical definition of a jet implies that the fluid effluent is under pressure, resulting in a coherent stream of the fluid through the medium (regardless of whether that medium is the same material as the fluid stream or not). In your example of paddle wheels, there is no stream of fluid propelled rearward. Sure there is a net momentum change, but the affected fluid particles are quickly absorbed back into the surrounding medium; in other words, the momentum imparted on these molecules is relatively small compared to the viscosity of the fluid.
In a jet stream, however, the net momentum imparted on the fluid particles is very high with respect to the fluid viscosity, resulting in a stream that persists far down-stream of the jet nozzle (which, if you want to get technical, I believe might be part of the definition of a jet.. not sure if you can have a practical jet without a fluid nozzle?). This can often be several times the length of the craft itself, as is the case with Sea-doos and, I believe, most turbofan/turbojet aircraft. The large difference in velocity/momentum between the jet and the medium prevents the re-absorbtion of the stream; you get boundary layers and vortices at the interface, but those effects dont' become noticeable until you are far down-stream of the jet nozzle.
I guess what I was trying to point out is that alot of the time we tend to think of a "jet engine" (or turbfan/turbojet engine) as being all one unit, while something like in a Sea-doo is entirely separate; ultimately, while the powerplants of "turbine engines" and pump-jet engines may differ, the basic concept in the sense of "they produce a jet of fluid to propel the craft" stays the same.
At this point though I would say we're getting pretty close to tomayto/tomahto ;)
Aikon-
Your analogy is faulty; if you indeed look at "the nice picture" in the article you linked, you'll notice that the combustion actually takes place in the combustion chamber, between the compressor and turbine stages; the exhaust stream is produced as a result of this combustion. Furthermore, the article you linked to was for a turbojet engine, which is nothing but a sub-class of the jet engine.
A jet engine does not specify that the energy source must be an internal combustion engine; it only specifies that thrust is generated in one direction by expelling a fluid (usually air/exhaust or water) in the opposite direction. Having said that, most common jet engines do use internal combustion. It is simply a matter of type.
A common example of a jet engine that uses a reciprocating internal combustion engine (typically two- or four-stroke) for power can be found in Sea-Doos, where a standard reciprocating internal combustion engine (like you would find in most automobiles) is used to drive an impeller that expels a jet of high-pressure water rearward of the craft, propelling the craft forward.
A common example of a jet engine that uses a continuous flow internal combustion engine is a turbojet engine, commonly found on military aircraft, or turbofan engine, commonly found on commercial passenger aircraft. Both turbojet and turbofan engines share a similar design in that the incoming air is pressurized using a compressor, mixed with fuel and combusted in the combustion chamber, and then expelled rearward of the craft for thrust. In this exhaust stream you will find a gas turbine that is used to power the compressor. In the case of turbofan engines, this gas turbine will also power a large fan located at the engine intake, which is where the majority of the thrust in a standard commercial jet-engine comes from.
The important thing to note is that reciprocating and continuous flow engines are both types of internal combustion engines; the public is just used to thinking of the ICE as a two- or four-stroke cycle system using pistons and a crankshaft, which is just not true. The combustion chamber in a turbojet or turbofan (or turboprop, now that I think about it) engine is still a confined-space combustion chamber used to burn air mixed with fuel at high pressures.
While I'm sure that looking at pretty pictures helps grade-schoolers learn "the way of things", typically it is considered good practice to read up on a subject before putting someone else down about not understanding it.
And in case you were wondering, I am a 4th year Aerospace Engineering student at the University of Toronto. While I don't claim to know everything there is to know in the world of combustion engines, I have had a fair amount of exposure both from private study and from experts and researchers in the field.
Aikon-
p.s. No, Wikipedia is not a reference I would ever cite in a research paper, though in this area its information is pretty good. I link to it only because it offers a great overall explanation of the processes involved. If you are sufficiently interested I suspect you will be able to get your hands on some real study material that goes into much more detail.
Not to mention bandwidth savings! You could write a Slashdot client that needed to grab only an array of memecodes with a corresponding parameter matrix (likely sparse), and you could reproduce the entire Slashdot thread client-side! Aikon-
Atheist is assuming a bit much, isn't it? Maybe the word you wanted to start with was "agnostic".. hmm?
Aikon-