for astra is [up to] 250mj, it provides pulses of 50 femtoseconds, every few femtoseconds - to the naked eye, a continuous beam. For many purposes (for instance, exciting inert gases in order for x-ray experiments), a pulsed laser is far more useful than a laser such as Vulcan which has to be recharged after each shot - and is also a lot less staff intensive, since staff can be reduced to competant troubleshooters in a control room who communicate with scientists in and around the target area.
silly me using diamond brackets to indicate lesser-than signs.;)
This isn't really news, being that the Vulcan laser in the UK reached petawatt capacity some months ago, after being awarded a grant for the purpose four years ago (see here) - the article doesn't mention the exact capacity, but I don't imagine that it's much more than a petawatt.
Another important thing to mention - again, not having read up on this - is that most scientific lasers are single-shot; most lasers are femto or petasecond lasers. From the same site as above (different news item, "Over the course of the three year upgrade project, the output of Vulcan's ultra-short pulse beam will be increased to 500J in a pulse of 500fs duration giving a power on target of 1 Petawatt (1015 Watts)" - for many purposes, a laser such as Astra suits many peoples purposes; whilst the pulse energy for astra is
As far as military applications are concerned, as mentioned in other threads, this laser would almost certainly be useless; it would be far too hard to aim, and in any case, lasers like this reach sufficient power that they require nitrogen-filled tubing in many laboratories in order not to ionise the air under certain circumstances (which creates irritating popping noises) - there are certain other technical details (such as the beam type) which render them inefficient for military purposes (although one scientist working with astra and vulcan did want to shoot a beam into space with an encyclopedia encoded in the beam pulse in order to transmit data to potential victims of human first contact).
Obviously, using expensive speakers entirely for that purpose would be pointless, but most computers nowadays ship with pci soundcards which outdo extremely expensive hifis for sound quality; it's the file that's being played which is the problem, something which a lot of geeks are woefully ignorant about. *grins*
Interestingly, a lot of audiophiles have built their own extremely high-quality CD players out of commercially available IDE cd drives (mostly creative drives) - the potential which computer hardware has is quite underrated, which is why almost without question I'd play mp3 files through a well-equipped computer - you're right, until a good hifi manufacturer makes a proper mp3 player it won't even vaguely match the quality of CDs - although not because of the mp3 decoding; the sound hardware which is in practically all portable players is woefully inadequate for amplification; only minidisk players have been equipped with decent quality interfaces, as yet - and an extremely high proportion of sound engineers (particularly theatrical engineers or those who don't do fixed-studio work) use these.
Actually, most professional engineers I know use SB live cards or equivalent for travelling setups; but if you really want to nitpick, you'd be far better off getting an aardvark board (http://www.aardvarkaudio.com/aasd-v1/products/249 6-main.html) or something from sonorus (http://www.sonorus.com/). Then again, re-mortgaging my house for some digidesign (http://www.digidesign.com/) kit would always be nice...
..if you're interested in Space Opera, his is the best; I recommend excession. Not exactly a niche market, but excellent science fiction nonetheless, and I guess it *would* be possible to pass him over.
Whether or not MP3 reduces the sound quality of any given source (which obviously it does), you can tell the difference between a production quality set of technics speakers and the 5watt multimedia speakers that shipped with an mmx-era tiny: in just the same way that a decent car will still handle well on a poor quality road, decent hardware will make the most of whatever sound you feed it.
With a few exceptions - notably headphones - this isn't the case. There are certain lines of sennheiser headphones, for instance, which sound dreadful when fed a 64kbps mp3 of classical music; however, even on a 160kbps mp3 feed, my pair of Sennheiser HD500s sound positively wonderful, especially when the music has as few channels as possible. This difference in headphones is mostly due to the fact that headphones aren't designed to playback recordings made for speakers - which your body naturally perceives accoustically due to the multiple, far-distanced soundsources and diffuse reflections off environment and shoulders. Even the most expensive headphones still find it extremely hard to compensate for this; the best solution is to use a binaural recording, made generally by a set of microphones embedded in a plastic or polystyrene fake head, such that playback sounds as realistic as possible.
In short, hardware DOES make a difference - even to a 128kbit mp3 feed. But what would sound bad on good hardware at that bitrate would sound bad on any set of speakers - and if you're really after audiophile sound quality, you won't be feeding a set of expensive speakers with a low-rate mp3 file.
Remember also that most recordings are now made digitally - it's extremely easy to get hold of even mp3 recordings of extremely high quality (256kbit mp3 files are practically indistinguishable from cds to the lay person's ear; with ogg vorbis, the compression artefacts drop vastly in occurance and this applies to an even greater degree)....
For a very long time, I debated a similar issue, and what I've found easiest to do is simply to stick a machine next to each 'media outlet' which exists in my house. My television has a displayless (asides from the tv) machine with an svideo output card, and my hifi has an old toshiba laptop plugged into it (120MHz machine). For times when I want really excellent sound, I have a second hifi which tends to get plugged into a soundblaster live - but for the majority of the time, soundblaster sound from the laptop suffices.
This is what I find simplest, since as I have the house networked, adding nodes - or controlling them - is childs play. I can happily even sit on the sofa and remote control the computer via the TV, which will happily play videos off my desktop which have recently been downloaded, for instance. I would guess that Wirelessly networking this would be more convenient, and specifically wiring each device would be a little higher class (ie. sending gold signal wiring to amplifiers &c), but in general I've found the networking approach to be the most flexible (and I've done a fair amount of work as a sound engineer, so I speak from a little experience).
As far as internet radio in every room goes, you might be simpler wiring up lots of speakers - I would guess it depends on your house size. I'd just plug my one of my laptops into the room in question and solve the problem that way, but that's just me.;)
Even the fastest (armour piercing) ammunition has a comparatively low muzzle velocity (something like 2000 fps), although you're right; under most circumstances, bullet velocity decreases relatively quickly on account of air resistance and no form of propulsion besides the initial explosion in the breech of the rifle.
If you're interested, zvis.com, the personal homepage of a software programmer in the US, has some excellent java ballistics tools, which allow you to calculate the velocity of the projectile from a firearm given different bullet mass &c. Obviously the smaller the bullet the higher the velocity, but even at muzzle velocity, an armour piercing sabot round travelling at 2000fps (which is exceptionally high, for a smallarm) only makes 3000kph, as far as I can calculate off the top of my head, which is slower than this record attempt (I say, opening another copy of the article to check that I'm not sticking my foot in a large hole.)
..it was the first 3d game I'd ever played (either that or descent, they both occurred in fairly short order), and they both caused me to think extremely differently about computers and gaming.
..trawling the net for some information on this from another source, I came across this, which some html written by one of the researchers involved in the project, it seems.
Admittedly, it isn't much, but it has a bigger picture.:)
The original reason that cellphones were discouraged in aeroplanes - at least in some areas - was that since cellphones were changing basestations at a prodigious rate, it was initially difficult for cellphone companies to bill users, since the software written to syncronise with base stations wasn't designed to handle cellphones which switched every few seconds. I'm guessing, however, that this isn't a problem any more.
Given that cellphones operate on very differing frequencies to aeroplane equipment, surely it's simply a problem of harmonics or badly shielded cockpit equipment which causes these conflicts?.. I've worked with a lot of military radio equipment, and it's all designed to be interoperable, and this is part of the reason military equipment is quite so expensive; it's designed NOT to intefere with anything else the army uses. In addition, obviously, the anything-else is designed not to be interfered with, since if a few stray radio transmissions were all it were to require to cause accidents, the army would be incapacitated extremely easily.
Is anyone else worried by the potential terrorist threat? given that a CELLPHONE can send an aeroplane off course - and given how easy it is to sneak a cellphone turned on on board a plane - how hard would it be to smuggle equipment into a plane which interfered with cockpit electronics and transceiving equipment by design, and how much more potent would the damage which this could cause be?
..with those who take the debian line; as someone anonymously posted to newsforge, "Even the FSF's attempt to require credit in the GFDL is being considered non-free by the Debian project"; and as he or she goes on to point out, Debian ARE usually fairly thorough on principled issues like this. The point, to my mind, of FREE software is that it's free. And whilst the word 'free' has the immediate connutation of lacking monetary compensation, that's not all that the word means. For me, for something to be free requires it not to have certain other obligations attached to it; it goes against my principles - and against the karma of the notion of free software - to tie advertising into freely distributed software in this way. If authors really can't do without this manner of crediting in projects which they've contributed to of their own free will, perhaps they shouldn't have contributed to them for free in the first place?
How many slashdot readers run adware.. and why?.. how long might it be before 'free' software which had advertising in this manner decided that 'trading' adverts with other software authors would increase their user base? Really, it wouldn't take very much bending of the rules before free software looked like free websites. And do we really want geocities on our desktops?
One large retail company I worked for as a DBA still used a version of well-known DOS database package which can't have been last updated any later than 1990, and was probably much older. The floor of the office dealing with their product line had an office intercom and klaxon system - so that all of the employees could be informed when they needed to quit the database software (every 10 minutes or so) because the system wouldn't handle multiple users and they needed to syncronise the managed copy with a working copy linked into the store systems.:)
Slashdot Mirror
(paragraph three should have finished:
silly me using diamond brackets to indicate lesser-than signs. ;)
This isn't really news, being that the Vulcan laser in the UK reached petawatt capacity some months ago, after being awarded a grant for the purpose four years ago (see here) - the article doesn't mention the exact capacity, but I don't imagine that it's much more than a petawatt.
Another important thing to mention - again, not having read up on this - is that most scientific lasers are single-shot; most lasers are femto or petasecond lasers. From the same site as above (different news item, "Over the course of the three year upgrade project, the output of Vulcan's ultra-short pulse beam will be increased to 500J in a pulse of 500fs duration giving a power on target of 1 Petawatt (1015 Watts)" - for many purposes, a laser such as Astra suits many peoples purposes; whilst the pulse energy for astra is
As far as military applications are concerned, as mentioned in other threads, this laser would almost certainly be useless; it would be far too hard to aim, and in any case, lasers like this reach sufficient power that they require nitrogen-filled tubing in many laboratories in order not to ionise the air under certain circumstances (which creates irritating popping noises) - there are certain other technical details (such as the beam type) which render them inefficient for military purposes (although one scientist working with astra and vulcan did want to shoot a beam into space with an encyclopedia encoded in the beam pulse in order to transmit data to potential victims of human first contact).
go to the UK (or order off a UK book merchant): they're still distinctly in print over there. ;)
Obviously, using expensive speakers entirely for that purpose would be pointless, but most computers nowadays ship with pci soundcards which outdo extremely expensive hifis for sound quality; it's the file that's being played which is the problem, something which a lot of geeks are woefully ignorant about. *grins*
Interestingly, a lot of audiophiles have built their own extremely high-quality CD players out of commercially available IDE cd drives (mostly creative drives) - the potential which computer hardware has is quite underrated, which is why almost without question I'd play mp3 files through a well-equipped computer - you're right, until a good hifi manufacturer makes a proper mp3 player it won't even vaguely match the quality of CDs - although not because of the mp3 decoding; the sound hardware which is in practically all portable players is woefully inadequate for amplification; only minidisk players have been equipped with decent quality interfaces, as yet - and an extremely high proportion of sound engineers (particularly theatrical engineers or those who don't do fixed-studio work) use these.
Actually, most professional engineers I know use SB live cards or equivalent for travelling setups; but if you really want to nitpick, you'd be far better off getting an aardvark board (http://www.aardvarkaudio.com/aasd-v1/products/249 6-main.html) or something from sonorus (http://www.sonorus.com/). Then again, re-mortgaging my house for some digidesign (http://www.digidesign.com/) kit would always be nice...
..if you're interested in Space Opera, his is the best; I recommend excession. Not exactly a niche market, but excellent science fiction nonetheless, and I guess it *would* be possible to pass him over.
Whether or not MP3 reduces the sound quality of any given source (which obviously it does), you can tell the difference between a production quality set of technics speakers and the 5watt multimedia speakers that shipped with an mmx-era tiny: in just the same way that a decent car will still handle well on a poor quality road, decent hardware will make the most of whatever sound you feed it.
With a few exceptions - notably headphones - this isn't the case. There are certain lines of sennheiser headphones, for instance, which sound dreadful when fed a 64kbps mp3 of classical music; however, even on a 160kbps mp3 feed, my pair of Sennheiser HD500s sound positively wonderful, especially when the music has as few channels as possible. This difference in headphones is mostly due to the fact that headphones aren't designed to playback recordings made for speakers - which your body naturally perceives accoustically due to the multiple, far-distanced soundsources and diffuse reflections off environment and shoulders. Even the most expensive headphones still find it extremely hard to compensate for this; the best solution is to use a binaural recording, made generally by a set of microphones embedded in a plastic or polystyrene fake head, such that playback sounds as realistic as possible.
In short, hardware DOES make a difference - even to a 128kbit mp3 feed. But what would sound bad on good hardware at that bitrate would sound bad on any set of speakers - and if you're really after audiophile sound quality, you won't be feeding a set of expensive speakers with a low-rate mp3 file.
Remember also that most recordings are now made digitally - it's extremely easy to get hold of even mp3 recordings of extremely high quality (256kbit mp3 files are practically indistinguishable from cds to the lay person's ear; with ogg vorbis, the compression artefacts drop vastly in occurance and this applies to an even greater degree)....
For a very long time, I debated a similar issue, and what I've found easiest to do is simply to stick a machine next to each 'media outlet' which exists in my house. My television has a displayless (asides from the tv) machine with an svideo output card, and my hifi has an old toshiba laptop plugged into it (120MHz machine). For times when I want really excellent sound, I have a second hifi which tends to get plugged into a soundblaster live - but for the majority of the time, soundblaster sound from the laptop suffices.
;)
:)
This is what I find simplest, since as I have the house networked, adding nodes - or controlling them - is childs play. I can happily even sit on the sofa and remote control the computer via the TV, which will happily play videos off my desktop which have recently been downloaded, for instance. I would guess that Wirelessly networking this would be more convenient, and specifically wiring each device would be a little higher class (ie. sending gold signal wiring to amplifiers &c), but in general I've found the networking approach to be the most flexible (and I've done a fair amount of work as a sound engineer, so I speak from a little experience).
As far as internet radio in every room goes, you might be simpler wiring up lots of speakers - I would guess it depends on your house size. I'd just plug my one of my laptops into the room in question and solve the problem that way, but that's just me.
Cat5e is a wonderful thing.
Even the fastest (armour piercing) ammunition has a comparatively low muzzle velocity (something like 2000 fps), although you're right; under most circumstances, bullet velocity decreases relatively quickly on account of air resistance and no form of propulsion besides the initial explosion in the breech of the rifle.
If you're interested, zvis.com, the personal homepage of a software programmer in the US, has some excellent java ballistics tools, which allow you to calculate the velocity of the projectile from a firearm given different bullet mass &c. Obviously the smaller the bullet the higher the velocity, but even at muzzle velocity, an armour piercing sabot round travelling at 2000fps (which is exceptionally high, for a smallarm) only makes 3000kph, as far as I can calculate off the top of my head, which is slower than this record attempt (I say, opening another copy of the article to check that I'm not sticking my foot in a large hole.)
..it was the first 3d game I'd ever played (either that or descent, they both occurred in fairly short order), and they both caused me to think extremely differently about computers and gaming.
;)
This started a downward spiral..
..trawling the net for some information on this from another source, I came across this, which some html written by one of the researchers involved in the project, it seems.
:)
Admittedly, it isn't much, but it has a bigger picture.
http://www.stanford.edu/~mckinney/intel.html
The original reason that cellphones were discouraged in aeroplanes - at least in some areas - was that since cellphones were changing basestations at a prodigious rate, it was initially difficult for cellphone companies to bill users, since the software written to syncronise with base stations wasn't designed to handle cellphones which switched every few seconds. I'm guessing, however, that this isn't a problem any more. Given that cellphones operate on very differing frequencies to aeroplane equipment, surely it's simply a problem of harmonics or badly shielded cockpit equipment which causes these conflicts?.. I've worked with a lot of military radio equipment, and it's all designed to be interoperable, and this is part of the reason military equipment is quite so expensive; it's designed NOT to intefere with anything else the army uses. In addition, obviously, the anything-else is designed not to be interfered with, since if a few stray radio transmissions were all it were to require to cause accidents, the army would be incapacitated extremely easily. Is anyone else worried by the potential terrorist threat? given that a CELLPHONE can send an aeroplane off course - and given how easy it is to sneak a cellphone turned on on board a plane - how hard would it be to smuggle equipment into a plane which interfered with cockpit electronics and transceiving equipment by design, and how much more potent would the damage which this could cause be?
..with those who take the debian line; as someone anonymously posted to newsforge, "Even the FSF's attempt to require credit in the GFDL is being considered non-free by the Debian project"; and as he or she goes on to point out, Debian ARE usually fairly thorough on principled issues like this. The point, to my mind, of FREE software is that it's free. And whilst the word 'free' has the immediate connutation of lacking monetary compensation, that's not all that the word means. For me, for something to be free requires it not to have certain other obligations attached to it; it goes against my principles - and against the karma of the notion of free software - to tie advertising into freely distributed software in this way. If authors really can't do without this manner of crediting in projects which they've contributed to of their own free will, perhaps they shouldn't have contributed to them for free in the first place?
How many slashdot readers run adware.. and why?.. how long might it be before 'free' software which had advertising in this manner decided that 'trading' adverts with other software authors would increase their user base? Really, it wouldn't take very much bending of the rules before free software looked like free websites. And do we really want geocities on our desktops?
One large retail company I worked for as a DBA still used a version of well-known DOS database package which can't have been last updated any later than 1990, and was probably much older. The floor of the office dealing with their product line had an office intercom and klaxon system - so that all of the employees could be informed when they needed to quit the database software (every 10 minutes or so) because the system wouldn't handle multiple users and they needed to syncronise the managed copy with a working copy linked into the store systems. :)
..are belong to us. Iain M Bank's culture GSVs (General Systems Vehicles) own you all. ;).. 26km of pure power. 0:)
Because obviously technology is geographically specific.