Erm as a point, both the British and the germans developed jet-fighters at roughly the same time, the german offering was countered by the meteor, and Sir James Wittle developed the jet engine (not that anybody funded him, props were tried and tested) before ww2 even started, it had been tested in the UK something like 10-20 years before one actually flew / was taken seriously.
I was not too worried about ww2 not sparking off that set of inventions, speeding it up maybe, but not sparking it off.
Pipes. The space elevator is a thin carbon nano-tube ribbon, you can't pump anything up it. And the pipes would need a weight to length ratio of roughly the same (7.5kg per km) and have a massive tensile strength since the weight of that 'weightless' hydrazine would be massive.
You would need to also maintain the CM at exactly geosynch at all times, not correct afterwards, since then you would need to deal with intertia of the cable falling to earth, and you are essentially lifting 20 tonnes via conventional rockets plus a nice 35,000+ km cable, somewhat inefficient (some would say stupid, but not me:) ).
Second, with the ground based anchor, contrary to popular misconceptions the centre of mass is always EXACTLY at geosynch, its a self regulating system, the amount of mass that base station supplies to the system for calculating the centre of mass is 100% related to the tension of the cable at the base. If you put a car on the cable, the CM doesn't change, the tension of the ase changes and therefore the weight the base contributes to the system alters, and the centre of mass does not move a millimetre... Its actually far, far easier to have a base station.
The cable is under constant tension, this equates to load on the groundstation (and is considered mass for the centre of gravity calculations), if you have a car travelling up the cable then the load on the groundstation decreases, BUT the centre of gravity remains the same, just the tension (and thus the weight exerted at the groundstation, hence how it equalises) alters. Should the centre of gravity change then chances are that would collapse the elevator, since it is held exactly at geosynch (the tension at the base allows this) and the only real way it could alter is down (too heavy a car) and that will make the elevator collapse...
Actually there is. The reciprocal of the centripetal force (commonly known as the centrifugal force). Technically not a force in its own right, but simplified physics isn't necessarily wrong, just not 100% correct. The tension experienced on the cable WILL pull it straight and will offset the need to increase the angular momentum of the item being lifted, and from the ground station the pull is outward, the counterweight on the cable is exerting a force on the groundstation. So please understand what you are saying before you jump down someone's throat.
And as another point, there is no outward pull on an object on the end of the tether itself, just an inward force, BUT the tether does experience an outward pull, and so in fact the parent was correct.
Same as F=MV isn't actually correct, and yet people still use it, its only correct for when v is small, the actual equation involves lightspeed as a divisor something like F=cMV/(c-V) (c is lightspeed) although I might have remembered that incorrectly... Because obviously Einstein states that the intertia of an object rises exponentially as that object approaches lightspeed, still it makes tiny differences at the speeds we are dealing with normally....
My point is, technically correct is all well and nice but can get in the way of understanding.
First point, return it within 7 days as unsatisfactory (fault etc) and they have a legal requirement to refund you, so this is not quite half baked advice. (This is based on UK law tho).
If you are from the US, well I suspect it'd be the same, since the litigation chances are far far higher, being such a sue-happy country...
But...
Took a look at the Trade Descriptions Act (1968 - UK) - Still current, not been replaced yet...;)
Reading that, which you can find, here... http://www.dti.gov.uk/access/trade/ http ://www.consumereducation.org.uk/laws/english/L egalrights/07.htm
Google search to get the actual legislation (its online somewhere...)
Reading that it seems that if a shop sells you an item bearing the CD logo (And it is not a real CD, copy-protection etc), then they are technically in violation of the Trade Descriptions act since it does not fully comply with what that CD logo means. It is not a CD, it is not usable on CD compliant players etc...
There are two remedies, a court action (small claims since its cheap, but they'd have to pay for a lawyer:) ) And contacting your local trading standards office.
To comply, they would have to move the 'CD's elsewhere and label them differently. To a normal consumer, that'd be brilliant since they'd be suspicious and less likely to buy if they weren't sure it would work in their machine at home...
Simply report the store to your local trading standards, or warn them, and then get those fake CDs segraggated...:)
I may do that at my local supermarkets etc..
BMG would absolutely HATE to have their CDs moved away from the rest because they are no longer true CDs and in fact there may have to be a disclaimer that the 'CD' will not play in all players, thus getting the public to shun them.
If you want to stop the copy-protection of CDs then this seems a pretty decent way to do it.
However, I'm not for advocating copyright violations (its not piracy or theft), and I feel you should buy music to listen to it, any CDs I buy I want to be able to play in all my players, stereo, computer, car, etc. I don't see why I should be penalised for what the music industry believes (no evidence yet) others are doing.
Looking at BMG's site, they say that 1.9Billion copies were made in 2001, meaning that the copy ratio is 1-1, 2000 it was 2-1. But the best thing is that the 33% drop in sales you'd expect with that level of difference in copying, was not seen, a mere 5% by value... Now to me this does not seem like there are billions of CDs being copied, and that the music industry is dying. A 5% drop during a global recession where other markets have dropped by 50% is not that much of an impact, and to claim that a 33% increase in copying led to a 5% decrease in sales (by value) just means to me that they really are just making up the figures to hoodwink the public.
It's hard to come up with figures, but you have to at least make them tally internally. Also, someone I know watched a film recently at the cinema, found it on DivX, downloaded and watched on his PC (for free), and then wen't out and bought the DVD. How exactly is the 'piracy' of the DivX hurting the sales in that respect, when he wasn't going to buy the dvd before he watched it on DivX and decided to afterwards cause he liked it more the second time he saw it... (Ok so that was a dvd / movie reference, the same goes for songs etc...)
I don't 'steal' so why can't I enjoy the music I paid for? Well sod that. cabling is dirt cheap, making an almost perfect copy is dirt cheap to, in SPITE of ALL the music industry can do, so if I want MP3s to play on my machine, I'll make them.
I won't post them to Kazaa or anything, that'd violate my principles, but someone will, and that first analogue copy will be made digital, and then its perfect from then on. The more you attempt to stop it, the more it will be spread.
I don't understand why they can't understand that, you cannot stop people from copying it, short of entering their homes at random intervals and checking everything, whilst p2p exists, then it only takes one person to breach the copy-protections put into place and then it spreads like a virus.
CDs and CDRs are not different IF THEY ARE SINGLE SESSION.
Older CD drives cannot hack the multi-session CDs, BUT single session copies are identicle to AudioCDs, and in fact data CDs. Undetectable to CD-Drives old / new.
Some car audio systems (Normally cheapo personal CD player conversions) use low powered lasers / optical pickups, and hence weren't able to read SOME Single Session CDRs (Depending on the quality of the burner and CDR media itself - been there since 2x was the tops). But they couldn't read anything but the cleanest CDs either so its no great loss.
So Single Session CDR == CD Multi-Session CDR != CD
Also, the format can be comprehended, and that is the major issue, its that the format LOOKS like what it expects, but that it then does things it doesn't, like put a second start-stop table in for each burn, lead-out/ lead-in sections in the middle of the cd, etc... Thus it can read it but treats it as a very very skippy CD, and can't access all of the data on it (audio or actual data)...
Please get facts right before giving an statement such as the above.
Erm, no it is not endothermic, if it were endothermic, then not only would it require heat to start, but it would not be self-sustaining and would keep needing heat just to keep burning.
You are correct that it needs heat to start, but once it is triggered the chemical reaction generates heat, and thus the reaction self-perputuates (aslong as there is fuel and oxidiser). I've never noticed a fire to burn cold, and cold exhaust fumes have never been an issue. Car engines have cooling systems, not heating systems (For the engine), car's overheat in traffic jams, not freeze, etc...
It is exothermic.
The definition for exothermic and endothermic reaction is not the initial requirements to trigger a reaction, BUT the result of the reaction itself. If a reaction requiring heat is endothermic then it CANNOT be sulf-sustaining, if it is exothermic then it has a chance at being self-sustaining.
(Exothermic means the reaction gives out heat, endothermic means the reaction absorbs heat)
the formula should be: CxHy + O2 ----> CO2 + H2O + HEAT
The heat is generally what we use to do useful work, normally in the form of gaseous expansion driving pistons or turbines....
The flywheel in car engines is between the clutch and the engine. Its purpose is to buffer the power coming from the pistons and allow them to compress the next stroke etc.
Pistons only provide power for 1/4 of their cycle, inhalation, compression, expansion, exhalation (yes there are better words for it, bah). Only the expansion phase generates power, and that is a massive shock shortly after ignition and then a fade away as the hot high pressure gas drops in pressure as work is extracted.
The flywheel takes this, smoothes it, it is nothing to do with speed maintainance when you change gears.
In the trains a flywheel would be used to: a) Store braking energy, b) Store excess drive energy
This rotational energy could then be directed to the wheels to provide extra torque when needed.
This is about the 100th post claiming that a SF story is a good basis for physics extrapolation.
Please stop, I'll pay you to stop.
Right.
Point 1.
In order for ANYTHING to be carried up the cable the cable can't be in balance, all those who said it is, they're wrong. If it were in balance it would be like trying to climb a kids helium balloon, you stay still and the balloon comes down to you. Admittedly with the inertia of the cable you'd be able to get off the ground but the cable will be going down faster than you can climb it.
At the point the cable is attached to the base station nore tension than the total mass of the climber and cargo is required, and that was mentioned to be 13 tonne climber, 20 tonne cargo (although these values might be wrong...)
So we already have over 33 tonnes of tension on the cable, of course to accelerate the climber we need even more tension, so its likely to be 40 tonnes.
The previous article mentioned much less than that, but anyway, the point is that the cable will be under tension...
The reason for this is so that you can pull climbers up this cable.
So.
In order to have 20,000 km of cable fall to earth (with a total mass of 150 tonnes - 7.5kg per km, you do the maths) you must cut it 20,000km. 80,000 km of the cable flies out into space due to all that tension, 20,000 km of thermally weak cabling drops to earth. (The reason for avoiding lightning storms is not that it can't conduct, its that the resultant heat would destroy the cable, noting that re-entry would do the same)...
With the cut of the cable the anchor platform would drop by several metres as the tension tonnage (lets say 40 tonnes) is suddenly gone, then the cable is yanked down towards earth, (this is ontop of gravity). The lowest parts of the cable survive intact, probably several miles of it. However this causes almost no damage / injury at all since its like dropping a piece of string out of an aeroplane, it just won't hurt. There is the possibility of a paper cut type thing, but it is very low since rectangles don't cut straight down, they spin and flutter due to turbulence and irregulaties in the material and airflow.
Terminal velocity of the cable in atmosphere is less than that of a piece of string, outside of the atmosphere, it'll pick up a great deal of speed before hitting the atmosphere, but that will cause it to burn up, leaving carbon nano-tube / carbon dust.. The rest of the cable, say 150 miles or so from the intact chunk to the burn out portion will be torn by sheer stressing and twisting so that a number of smaller chunks will fall to the earth, reaching a slower terminal velocity than a piece of string.
All in all there will be some intact cable, 150 miles of ripped up cable, and thousands of miles of destroyed cable.
Kim Stanley Robinson's space elevator used conventional materials, weighed in at the billions of tonnes and impacted on a planet with very very low atmosphere, hence less burnout, higher terminal velocity and basically fiction, the destruction would have been great, but being a story, I'm not too stressed.
What people fail to realise is that 1 km of this ribbon weighs only 7.5 kg!!! It is amazingly light.
Imagine if the cable was made from a 5cm wide piece of paper (ignoring the fact that the paper is actually heavier)... Would you be worried if that fell from orbit? Do you understand the weight to length ratios and the sheer unfrightening and non-destructive impact of it *should* it break???
It would be a financial disaster, but loss of life would be close to zero, unless a climber was going up and fell, but even then recovery should be possible, plus the odd paper-cut. (Ok so decapitation would be possible, but if you get under cover there'd be no problem)
Next, you could tow in a large asteroid, but that raises a few more issues.
1) What if something went wrong as it was towed??? Well that's your asteroid impact for you right there... 2) So you have a million tonne + asteroid in a NEO that you want to move, so you move millions of tonnes of equipment to do this. A little costly. 3) If I were a terrorist, if I could get that asteroid to hit, that'd be a tsunami alright, and a major major terrorist event, imagine it hitting the twin towers instead of a plane, well there goes the towers, and the city..
Stress is identical, tension is required either way, one uses a massive lump of rock just beyond the geosynch orbit, another uses the mass of a long cable extending thousands of km past the geosynch orbit.
Manufacturing economies of scale, ie its easier to build more cable that to build another anchor device and move an asteroid into place, plus the losses when a cable snaps is much much less, you don't have to put the asteroid back into orbit.
If you had looked at the crossectional area of the proposed cable you would notice that it is much like a sheet of paper, hence some winds will barely affect it, others will cause it to sway, but the overall windresistance to total length / tension is tiny, and can be easily compensated for.
One last thing I'd like to reiterate, is that SF books are not the best source of information regarding real life, being a SF fan myself I understand that its cool, but it doesn't have any great bearing on the real world, and some stuff that seems 100% plausable just isn't.
If you are interested in orbital tethers, space elevators, sky-hooks etc. The do a google search on them, there are loads of ideas, analysis etc.
Been fun, hope this helps to address some things, and please, please, read the article before you post, visit the sites, research.. If you're not a troll going for FP then you have the time... It does mention these things in it, and its tiresome to have to post it again...
This was all covered to death last time this story was posted...
Unfortunately at the speeds they are travelling and in bad weather conditions you can't always see other jets, and if you both bank in the same direction, well its not just going to dent your bumper.
The reason for radar and air-traffic control is that despite the pilots they cannot see and they cannot avoid things like you can if you were running, its just not that easy.
And if you had read the post you might have noticed that I mentioned it wasn't certain to cause crashes / deaths.
BUT I should point out that this could cause the collapse of confidence gained in air travel since Sept 11th in the states, and lead to even more financial damage. If I were a terrorist I'd go after the economy, and that has been hit pretty bad after the WTC crashes. If you could take down air-travel, then there will be an increase in cars, accidents and a general slowdown in businesses as travel is restricted, sure it would pick up again, but how many events would be needed to cripple airliners??? each time it is forgotten another attack occurs, and even IF not a single person dies the fears will increase. And its not exactly something you could stop....
Its not the same issue, not even close as an analogy, how about instead, we ban crisps.
Thats right, crisps, totally inert you might think, well some of them now use foil wrappers to keep them fresh... What if it were discovered that crinkling them up would generate a radio signal that crippled the plane? I know you would advocate banning crisps at this point, but what does that achieve? Nothing, because a simple piece of foil could be used to bring the plane down. I'm not saying that the planes should be the equivalent of nuke-proof, I'm saying that they ought to be safe from party-poppers.
Why you seem to be saying its ok to have something as simple as this take down a plane I don't understand.
My point is this: You can now build a device that uses simple electronics to disable some safety systems onboard a plane. To me this is not acceptible, to you well it seems like it is. And to ban some devices that as a side effect generate this interferrance, and claim to have solved the problem???? Thats why face recognition at airports is a dud, its false security and its not worth doing.
Its possible to jam signals or drown them out. A truck with a decent signal generator and amp could drown out an airport's air-traffic control.
Now, lets say that there is a problem in a particular airport, a bomb threat or something so that the planes are stacked above it, now if someone should jam / drown out the air-traffic controller with a high Wattage signal, and at the same time use the spark-gap transmitter to scramble the collision avoidance, now where are you???
Yes its a doomsday scenario, but it requires a number of devices:
a bomb threat - telephone call UWB devices, cheap personal stereo's and some cheap electrics. Signal blocker... Take some standard radio gear and beef up the wattage, saturate the signal band. Use a directional antenna to improve the signal strength and to make tracking harder... Use the signal blocker to trigger the UWB devices, and then you have a scenario..
Sure nothing might happen, but a well co-ordinated attack could easily cause some nasty accidents, especially if you rig it so that some extra flights are diverted to that airport before-hand...
The skills required are soldering and some knowledge of electronics.. These aren't criminal skills and the info you need is easily available on the net...
Does anyone else think that it should therefore be possible to create a small handheld device that say looks like a walkman/personal stereo, but contains an UWB transmitter? Activate it in a heavily traveled airspace and create chaos at best...
Rather than just try and ban the devices shouldn't they be working on methods of blocking the signals? Or altering the collision avoidance systems to cope with the interferrance?? Doesn't this smack of really bad shortsightedness?? Even if UWB is several years away, spark-gap transmitters ought to be homebuildable and with far more power than the average UWB transmitter.
I might be giving away ideas here, but doubt that terrorists read/. and that they couldn't have thought of it themselves:) In fact why bother being on the plane, have it in the baggage hold on a timer... It's not explosives, its a harmless walkman...
Just a thought, these things crop up when people try one solution to a problem, but they are just trying to prevent it. And even though people say prevention is better than cure, cure is far more reliable.
Z.
P.S. Sorry to bring the 'terrorist' angle up again but this strikes me as a stupid thing to do, even if it never occurs. When you have people's lives at risk it ought to be cure, not a reliance on prevention.
Well you could, but there are reasons why this is a bad idea.
I think the exploding birds might cause an issue, and the chance of serious injury / death if something managed to reflect some of the energy, a metal fragment etc, or a plane was blown off course.... The reason the beam is so wide is to reduce the energy per metre squared to below safe levels, thus not hurting anything, BUT that increases the surface area needed to gather that same total energy.
Z.
Re:stunned at the weight
on
Going Up?
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· Score: 1
Stunned that it weighs so little, especially when you consider that it has to have a tensile strength of at least 280 tonnes (at geosynch). Just to lift itself and cargo.
I looked into orbital tethers and sky-hooks a while ago, and the weight to strength ratio needed is massive. A metre of this stuff weighs in at 7.5 grams, and can hold 280 tonnes? Thats very strong. They may thicken it as the cable rises (since the greatest tension is held at the geosynch point) but they said it was only a few centimetres squared (at ground level).. I'm very impressed, but will be more so when you can see this tiny line shoot straight up.
By the sounds of it there will be over 10 tonnes of tension on the base of the cable (twice the lift capacity at least), the weight of the floating platform will likely be in the tens of tonnes and easily counter balance this. The weight of the cable beyond geosynch orbit will provide this tension and that would mean that you could climb up it and the only change would be a reduction in the tension beneath you.. You could get away with having a large weight just beyond geosynch orbit, and in fact that would be how I would do it, since the centrifugal effect would mean that you would have a gravity of sorts.. Of course that means you'd need to put something up there or bring something into orbit.
The main use I can think of for this technology is power. Orbital power stations would be far more efficient and always on, but beaming that power down would be a nasty thing, nobody likes mile wide+ microwave beams, plus the realestate to recapture the huge beam is expensive. This orbital elevator could be used to pipe that power down to earth, and get re-distributed from there, and that would be a pollution free, cheap (after a while) way to power the earth. If it works I'd expect several larger scale projects to occur, likely land based.
As another point, mainly to the doomsayers about the cable breaking, the issue is where it will break.. if it breaks at the base it will simply leave the earth and not crash anywhere, only the bit below the break will fall to earth... The 'worst' case would be if it breaks at the geosynch point, then you have 36,000 km's of cable falling.. Luckily most of it would burn up, leaving only a small section (odd km of it) at the base to hit the sea.
Z.
Re:Great news, but
on
Going Up?
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· Score: 5, Insightful
Where to begin???
Point 1: Neo to attach to. Unnecessary. You can achieve the same thing with a really long teather and a 1 kg weight on the end. Did you not notice that the cable was 100,000 km long, when geosynch orbit is only 36,000 (miles or km I can't remember, but even if it is miles that would make it 57odd thousand km up, far less then the 100,00 required) the extra thousands of km are used to provide leverage and a decent ratio for the mass to be lifted. Although I am curious to know what you mean by strong enough. All you need to do is get an object, in geosych orbit, move it to an outer orbit but keep it at the same angular velocity (how long it takes to orbit the earth) and the resulting centripetal force can be used to pull against when pulling up mass. 'Strong' neos aren't needed, a collection of cotton wool would do it, if there was enough and it was far enough out.
Point 2: Constant height. Not actually necessary, the water level is pretty flat (aside from tidal variations due to the moon and the sun) BUT the cable is under constant tension thus would forgive a certain amount of play. In fact the cable has to be at over 5 tonnes of tension at the base to be able to lift the mass required.
Point 3: Energy required for lift. Actually you are wrong again, the energy required is less. When you use a reaction engine fully half the energy required to boost you is wasted throwing mass out in the opposite direction. HOWEVER along with this is the fact that they are going to be using lasers to drive photovoltaic cells to drive electrical motors, and this could (in theory) be purely sunlight driven.
Point 4. Location. The ocean isn't too bad, a simple cargo ship deliver the cargo and it lifts. Sure its not rail or lorry but its good enough. Most of the oil the US needs is shipped via tankers, why can't a few satelites?
Point 5. Anti-gravity. (Ignoring the racist angle) this is an unproven experiment, and it should be noted that 2% is a little different to lifting the item into orbit.
As an aside, the cable itself will weigh in at a stunning 750 tonnes. Of that 480 tonnes (metric) will be above geo-synch orbit (assuming 36k km or should that be Mm???) and not likely to crash down.
I applaude them, but hope it does all work even though I have my doubts...
The tensile strength of the cable needs to be huge.. 7.5 kg per km, and that needs to hold around 270 tonnes, its a hell of a challenge....
Ahh but you signed up for it when you joined... Sheesh...:) Still they allowed you to 'opt-out' when you left...
Its impressive though that IBM's spam filters are so good, having seem friends of mines' IBM addresses on the web, they haven't received a single spam mail through to their account.. And yet my home address harvested from the same page now gets around 30 a day.. So some filtering software does work..
The main problem with acrylic / perspex cases is the lack of radiation shielding..
Macroman from Bit-Tech.net suggested that the foil he uses on one of his cases (reflective unless internally lit) might block the radiation plus give a great effect.
If you place acrylic cases next to your TV or radio, then you can see the interferrence..
Also I remember reading that an open case / case window was screwing around with a remote garage opener..
Just a thought if anyone is planning to use it as a tv top box since it looks so nice:)
Technically it is a sound wave, I never mentioned the frequency, merely the amplitude, it could be running at 5kHz, I'm not saying its currently possible with our level of technology but in theory it would be possible. Yes you can say that it is best to model it as a wind, but at what point do you draw a line? Limits of human hearing?
I also wasn't talking about the device mentioned in the article, since it really isn't going to be able to create the necessary level of power. Especially since the ultrasonic wave's amplitude will need to be around the same level I believe to recombine to the necessary force. And its harder to create high frequency high amplitude sound than low frequency high amplitude sound. I merely was arguing that in theory it is possible to knock someone down with what would be classed as a sound wave.
As for it being impossible to create a sonic gun, I don't think so, very difficult, but you won't necessarily need to use explosives to generate it. As a point actually, explosives don't create true sound waves. The majority of explosives (not atomic) work by creating vast quantities of gas (normally CO2 or CO) in a very short space of time, thus you end up with a shockwave, this shockwave is a positive displacement of air, a high pressure wave. Whereas a soundwave doesn't actually move the air, the wave travels through the medium without moving the medium (as a net result; there is some movememnt as the wave travels, but it is on average zero movement). I was actually talking about a true soundwave, +x -x of the medium's pressure.
Conservation of momentum is not really a limiting factor, true its not going to throw the target 20 miles, and in fact, will literally only knock him down akin to a wave on a beach, pretty much on the spot because of the sudden changes in the directions of the force, pull towards the low pressure, pushed by the high pressure..
Z.
Re:I'm inclined to think this is bullcrap.
on
Voices in Your Head
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· Score: 1
Sound can be focussed.
Sound can be reflected.
Sound can be refracted.
I was going to explain it all, but then I remembered a simple way to prove it to you.
Place your hands near your ears, like you were going to put them over your ears but hover them around 2 inches off. Now hiss. While hissing twist your hands.. You will notice an alteration in the volume as your hands pass a certain point, this is because the high frequency noise is bouncing off your hands and you are receiving more hiss.
This empirical test shows that sound can be reflected, and if it can be reflected then it can be focussed, and it probably can be refracted. (I know it can but I can't think of a simple test for it).
Sound is a number of waves travelling through a medium, air, thus although it is not a wave and a particle in the same sense as items in the electromagnetic spectrum, it does have a particulate medium to travel through.
And as a point how do you expect "to collect the DIFFUSED waves." if they cannot be reflected???
How do parabolic microphones work? Speakers with bass reflex ports??
True yes, human bodies do not have strong resonance frequencies, and that's primarily because we are soft. Only our bones are particularly hard. As you vibrate innacuracies such as your breathing, blood being pumped all vary your 'resonant' frequency. Even moving your arm alters the standing wave you would produce, thus it would be incredibly difficult if not impossible to shatter someone (even their bones since they change according to the stresses and contact with other materials).
Having said that however, the assertion that it is impossible to 'knock someone over' with a sound wave is false. It is actually possible, and here's why:
Sound is nothing more than our brains interpreting compressions and refactions of the atmosphere. These waves can vary in frequency, hence the higher and lower pitched noises, and can vary in amplitutde, hence the louder and quieter noises. What these really are are 'walls' (concave-flat depending on the source) of high and low pressure air radiating from the sound source. Akin to waves in the sea, you have a trough, low pressure and a peak, high pressure. If you had a wave of sufficient amplitude you could be running from vacuum to 2 atmospheres (might actually be higher than that). This creates a wave scenario where you have a fast moving ~600MPH wall of air of a pressure difference of two atmospheres. Easily sufficient to knock someone down, its akin to jumping out of a plane doing 1200 MPH, it throws you back, fast.
The reason normal sound does not do this is that the amplitude is too small, even the loudest of concerts doesn't have the 'directed' power (noting that the aim is not to focus the power on someone, but to provide it to all the audience) necessary to knock someone down.
This is not going into the stun devices, but phasors cannot work anyhow, looking at the link the person who wrote the page seems to believe that they were based on laser technology, this causes a problem since it will just burn holes in people, that would stun me, but I'd likely die shortly afterwards. The link has very little to do with sonic based weaponry, which is a pity.
If you gain a mod chip for a PS it generally does three things for you:
1) Allows you to play non-'original' disks. (A semi-dodgy area, fair use says a backup is permitted) 2) Allows you to play discs from other regions (No illegality here.) 3) Allows you to play DVDs from other regions. (Perfectly legal)
One of the selling points on a PS2 is that it plays DVDs, and hence you can factor in that cost of a DVD player when buying a PS2, and as pretty much ANYBODY in a country that does not fall into region 1 knows DVDs are somewhat more expensive there... Not mentioned the staggered release dates, region 1, then 6 months later the rest of the world.
Games are also 'zoned' in a similar manner, brought out eariler, different pricing, and in fact different games (well features I guess)..
Why companies playing in a global market should attempt to segment, purely for the purpose of increasing profit... If you import DVDs from the states to the UK you still pay the VAT, and hence the tax arguement doesn't really cut it with me. Some items really are value added for the zones, but so far I've only noticed this on cars, not Computer related items.
And so to sum this up, there are perfectly legal and legitimate reasons for installing / purchasing a mod chip. I'm not saying that everyone has these goals in mind when they buy or sell them, but I am saying that to tar everyone with the same brush is a little harsh, and wrong.
To reply to the quote in the parent: This was totally unrelated to the first sale principle, it was the selling of mod-chips (oh and those copied games). Once you have bought the hardware there is nothing illegal about altering it. Sure the DMCA may come into force if you circumvent copy-protection, BUT I'm not sure if that applies if you don't distribute the 'crack'. At least nobody will know since there will be no publicity.. If you buy a ps2, crush it and use it as a doorstop, you can, and there is NOTHING Sony can do about it, even if you publish it, hell that probably violates the DMCA since the copy-protection is circumvented... Hmm I wonder what happens to scrapped machines??
Sony (and Sega, MS, etc) want to stop this because traditionally Europeans (and other areas, sorry about the view - I'm from Europe) will tolerate much higher pricing than their American counterparts, thus better profit margins..
Z.
P.S. I believe PS2 Games are zoned, although I'm not 100% sure.
Slashdot Mirror
Erm as a point, both the British and the germans developed jet-fighters at roughly the same time, the german offering was countered by the meteor, and Sir James Wittle developed the jet engine (not that anybody funded him, props were tried and tested) before ww2 even started, it had been tested in the UK something like 10-20 years before one actually flew / was taken seriously.
I was not too worried about ww2 not sparking off that set of inventions, speeding it up maybe, but not sparking it off.
Z.
Issue 1:
:) ).
Pipes. The space elevator is a thin carbon nano-tube ribbon, you can't pump anything up it. And the pipes would need a weight to length ratio of roughly the same (7.5kg per km) and have a massive tensile strength since the weight of that 'weightless' hydrazine would be massive.
You would need to also maintain the CM at exactly geosynch at all times, not correct afterwards, since then you would need to deal with intertia of the cable falling to earth, and you are essentially lifting 20 tonnes via conventional rockets plus a nice 35,000+ km cable, somewhat inefficient (some would say stupid, but not me
Second, with the ground based anchor, contrary to popular misconceptions the centre of mass is always EXACTLY at geosynch, its a self regulating system, the amount of mass that base station supplies to the system for calculating the centre of mass is 100% related to the tension of the cable at the base. If you put a car on the cable, the CM doesn't change, the tension of the ase changes and therefore the weight the base contributes to the system alters, and the centre of mass does not move a millimetre... Its actually far, far easier to have a base station.
Z.
Actually the groundstation does this for you.
The cable is under constant tension, this equates to load on the groundstation (and is considered mass for the centre of gravity calculations), if you have a car travelling up the cable then the load on the groundstation decreases, BUT the centre of gravity remains the same, just the tension (and thus the weight exerted at the groundstation, hence how it equalises) alters. Should the centre of gravity change then chances are that would collapse the elevator, since it is held exactly at geosynch (the tension at the base allows this) and the only real way it could alter is down (too heavy a car) and that will make the elevator collapse...
Z.
Erm...
Actually there is. The reciprocal of the centripetal force (commonly known as the centrifugal force). Technically not a force in its own right, but simplified physics isn't necessarily wrong, just not 100% correct. The tension experienced on the cable WILL pull it straight and will offset the need to increase the angular momentum of the item being lifted, and from the ground station the pull is outward, the counterweight on the cable is exerting a force on the groundstation. So please understand what you are saying before you jump down someone's throat.
And as another point, there is no outward pull on an object on the end of the tether itself, just an inward force, BUT the tether does experience an outward pull, and so in fact the parent was correct.
Same as F=MV isn't actually correct, and yet people still use it, its only correct for when v is small, the actual equation involves lightspeed as a divisor something like F=cMV/(c-V) (c is lightspeed) although I might have remembered that incorrectly... Because obviously Einstein states that the intertia of an object rises exponentially as that object approaches lightspeed, still it makes tiny differences at the speeds we are dealing with normally....
My point is, technically correct is all well and nice but can get in the way of understanding.
Z.
If I had mod points right now, that'd be a funny :)
And I agree.
A happy UK citizen.
Z.
First point, return it within 7 days as unsatisfactory (fault etc) and they have a legal requirement to refund you, so this is not quite half baked advice. (This is based on UK law tho).
;)
p ://www.consumereducation.org.uk/laws/english/L egalrights/07.htm
:) ) And contacting your local trading standards office.
:)
If you are from the US, well I suspect it'd be the same, since the litigation chances are far far higher, being such a sue-happy country...
But...
Took a look at the Trade Descriptions Act (1968 - UK) - Still current, not been replaced yet...
Reading that, which you can find, here...
http://www.dti.gov.uk/access/trade/
htt
Google search to get the actual legislation (its online somewhere...)
Reading that it seems that if a shop sells you an item bearing the CD logo (And it is not a real CD, copy-protection etc), then they are technically in violation of the Trade Descriptions act since it does not fully comply with what that CD logo means. It is not a CD, it is not usable on CD compliant players etc...
There are two remedies, a court action (small claims since its cheap, but they'd have to pay for a lawyer
To comply, they would have to move the 'CD's elsewhere and label them differently. To a normal consumer, that'd be brilliant since they'd be suspicious and less likely to buy if they weren't sure it would work in their machine at home...
Simply report the store to your local trading standards, or warn them, and then get those fake CDs segraggated...
I may do that at my local supermarkets etc..
BMG would absolutely HATE to have their CDs moved away from the rest because they are no longer true CDs and in fact there may have to be a disclaimer that the 'CD' will not play in all players, thus getting the public to shun them.
If you want to stop the copy-protection of CDs then this seems a pretty decent way to do it.
However, I'm not for advocating copyright violations (its not piracy or theft), and I feel you should buy music to listen to it, any CDs I buy I want to be able to play in all my players, stereo, computer, car, etc. I don't see why I should be penalised for what the music industry believes (no evidence yet) others are doing.
Looking at BMG's site, they say that 1.9Billion copies were made in 2001, meaning that the copy ratio is 1-1, 2000 it was 2-1. But the best thing is that the 33% drop in sales you'd expect with that level of difference in copying, was not seen, a mere 5% by value... Now to me this does not seem like there are billions of CDs being copied, and that the music industry is dying.
A 5% drop during a global recession where other markets have dropped by 50% is not that much of an impact, and to claim that a 33% increase in copying led to a 5% decrease in sales (by value) just means to me that they really are just making up the figures to hoodwink the public.
It's hard to come up with figures, but you have to at least make them tally internally. Also, someone I know watched a film recently at the cinema, found it on DivX, downloaded and watched on his PC (for free), and then wen't out and bought the DVD. How exactly is the 'piracy' of the DivX hurting the sales in that respect, when he wasn't going to buy the dvd before he watched it on DivX and decided to afterwards cause he liked it more the second time he saw it... (Ok so that was a dvd / movie reference, the same goes for songs etc...)
I don't 'steal' so why can't I enjoy the music I paid for? Well sod that. cabling is dirt cheap, making an almost perfect copy is dirt cheap to, in SPITE of ALL the music industry can do, so if I want MP3s to play on my machine, I'll make them.
I won't post them to Kazaa or anything, that'd violate my principles, but someone will, and that first analogue copy will be made digital, and then its perfect from then on. The more you attempt to stop it, the more it will be spread.
I don't understand why they can't understand that, you cannot stop people from copying it, short of entering their homes at random intervals and checking everything, whilst p2p exists, then it only takes one person to breach the copy-protections put into place and then it spreads like a virus.
Sigh.
Z.
Not true again.
CDs and CDRs are not different IF THEY ARE SINGLE SESSION.
Older CD drives cannot hack the multi-session CDs, BUT single session copies are identicle to AudioCDs, and in fact data CDs. Undetectable to CD-Drives old / new.
Some car audio systems (Normally cheapo personal CD player conversions) use low powered lasers / optical pickups, and hence weren't able to read SOME Single Session CDRs (Depending on the quality of the burner and CDR media itself - been there since 2x was the tops). But they couldn't read anything but the cleanest CDs either so its no great loss.
So Single Session CDR == CD
Multi-Session CDR != CD
Also, the format can be comprehended, and that is the major issue, its that the format LOOKS like what it expects, but that it then does things it doesn't, like put a second start-stop table in for each burn, lead-out/ lead-in sections in the middle of the cd, etc... Thus it can read it but treats it as a very very skippy CD, and can't access all of the data on it (audio or actual data)...
Please get facts right before giving an statement such as the above.
Z.
Erm, no it is not endothermic, if it were endothermic, then not only would it require heat to start, but it would not be self-sustaining and would keep needing heat just to keep burning.
You are correct that it needs heat to start, but once it is triggered the chemical reaction generates heat, and thus the reaction self-perputuates (aslong as there is fuel and oxidiser). I've never noticed a fire to burn cold, and cold exhaust fumes have never been an issue. Car engines have cooling systems, not heating systems (For the engine), car's overheat in traffic jams, not freeze, etc...
It is exothermic.
The definition for exothermic and endothermic reaction is not the initial requirements to trigger a reaction, BUT the result of the reaction itself. If a reaction requiring heat is endothermic then it CANNOT be sulf-sustaining, if it is exothermic then it has a chance at being self-sustaining.
(Exothermic means the reaction gives out heat, endothermic means the reaction absorbs heat)
the formula should be:
CxHy + O2 ----> CO2 + H2O + HEAT
The heat is generally what we use to do useful work, normally in the form of gaseous expansion driving pistons or turbines....
Z.
You are wrong.
The flywheel in car engines is between the clutch and the engine. Its purpose is to buffer the power coming from the pistons and allow them to compress the next stroke etc.
Pistons only provide power for 1/4 of their cycle, inhalation, compression, expansion, exhalation (yes there are better words for it, bah). Only the expansion phase generates power, and that is a massive shock shortly after ignition and then a fade away as the hot high pressure gas drops in pressure as work is extracted.
The flywheel takes this, smoothes it, it is nothing to do with speed maintainance when you change gears.
In the trains a flywheel would be used to:
a) Store braking energy,
b) Store excess drive energy
This rotational energy could then be directed to the wheels to provide extra torque when needed.
Z.
I just can't take it anymore.
This is about the 100th post claiming that a SF story is a good basis for physics extrapolation.
Please stop, I'll pay you to stop.
Right.
Point 1.
In order for ANYTHING to be carried up the cable the cable can't be in balance, all those who said it is, they're wrong. If it were in balance it would be like trying to climb a kids helium balloon, you stay still and the balloon comes down to you. Admittedly with the inertia of the cable you'd be able to get off the ground but the cable will be going down faster than you can climb it.
At the point the cable is attached to the base station nore tension than the total mass of the climber and cargo is required, and that was mentioned to be 13 tonne climber, 20 tonne cargo (although these values might be wrong...)
So we already have over 33 tonnes of tension on the cable, of course to accelerate the climber we need even more tension, so its likely to be 40 tonnes.
The previous article mentioned much less than that, but anyway, the point is that the cable will be under tension...
The reason for this is so that you can pull climbers up this cable.
So.
In order to have 20,000 km of cable fall to earth (with a total mass of 150 tonnes - 7.5kg per km, you do the maths) you must cut it 20,000km.
80,000 km of the cable flies out into space due to all that tension, 20,000 km of thermally weak cabling drops to earth. (The reason for avoiding lightning storms is not that it can't conduct, its that the resultant heat would destroy the cable, noting that re-entry would do the same)...
With the cut of the cable the anchor platform would drop by several metres as the tension tonnage (lets say 40 tonnes) is suddenly gone, then the cable is yanked down towards earth, (this is ontop of gravity). The lowest parts of the cable survive intact, probably several miles of it. However this causes almost no damage / injury at all since its like dropping a piece of string out of an aeroplane, it just won't hurt. There is the possibility of a paper cut type thing, but it is very low since rectangles don't cut straight down, they spin and flutter due to turbulence and irregulaties in the material and airflow.
Terminal velocity of the cable in atmosphere is less than that of a piece of string, outside of the atmosphere, it'll pick up a great deal of speed before hitting the atmosphere, but that will cause it to burn up, leaving carbon nano-tube / carbon dust.. The rest of the cable, say 150 miles or so from the intact chunk to the burn out portion will be torn by sheer stressing and twisting so that a number of smaller chunks will fall to the earth, reaching a slower terminal velocity than a piece of string.
All in all there will be some intact cable, 150 miles of ripped up cable, and thousands of miles of destroyed cable.
Kim Stanley Robinson's space elevator used conventional materials, weighed in at the billions of tonnes and impacted on a planet with very very low atmosphere, hence less burnout, higher terminal velocity and basically fiction, the destruction would have been great, but being a story, I'm not too stressed.
What people fail to realise is that 1 km of this ribbon weighs only 7.5 kg!!! It is amazingly light.
Imagine if the cable was made from a 5cm wide piece of paper (ignoring the fact that the paper is actually heavier)... Would you be worried if that fell from orbit? Do you understand the weight to length ratios and the sheer unfrightening and non-destructive impact of it *should* it break???
It would be a financial disaster, but loss of life would be close to zero, unless a climber was going up and fell, but even then recovery should be possible, plus the odd paper-cut. (Ok so decapitation would be possible, but if you get under cover there'd be no problem)
Next, you could tow in a large asteroid, but that raises a few more issues.
1) What if something went wrong as it was towed??? Well that's your asteroid impact for you right there...
2) So you have a million tonne + asteroid in a NEO that you want to move, so you move millions of tonnes of equipment to do this. A little costly.
3) If I were a terrorist, if I could get that asteroid to hit, that'd be a tsunami alright, and a major major terrorist event, imagine it hitting the twin towers instead of a plane, well there goes the towers, and the city..
Stress is identical, tension is required either way, one uses a massive lump of rock just beyond the geosynch orbit, another uses the mass of a long cable extending thousands of km past the geosynch orbit.
Manufacturing economies of scale, ie its easier to build more cable that to build another anchor device and move an asteroid into place, plus the losses when a cable snaps is much much less, you don't have to put the asteroid back into orbit.
If you had looked at the crossectional area of the proposed cable you would notice that it is much like a sheet of paper, hence some winds will barely affect it, others will cause it to sway, but the overall windresistance to total length / tension is tiny, and can be easily compensated for.
One last thing I'd like to reiterate, is that SF books are not the best source of information regarding real life, being a SF fan myself I understand that its cool, but it doesn't have any great bearing on the real world, and some stuff that seems 100% plausable just isn't.
If you are interested in orbital tethers, space elevators, sky-hooks etc. The do a google search on them, there are loads of ideas, analysis etc.
Been fun, hope this helps to address some things, and please, please, read the article before you post, visit the sites, research.. If you're not a troll going for FP then you have the time... It does mention these things in it, and its tiresome to have to post it again...
This was all covered to death last time this story was posted...
Z.
Unfortunately at the speeds they are travelling and in bad weather conditions you can't always see other jets, and if you both bank in the same direction, well its not just going to dent your bumper.
The reason for radar and air-traffic control is that despite the pilots they cannot see and they cannot avoid things like you can if you were running, its just not that easy.
And if you had read the post you might have noticed that I mentioned it wasn't certain to cause crashes / deaths.
BUT I should point out that this could cause the collapse of confidence gained in air travel since Sept 11th in the states, and lead to even more financial damage. If I were a terrorist I'd go after the economy, and that has been hit pretty bad after the WTC crashes. If you could take down air-travel, then there will be an increase in cars, accidents and a general slowdown in businesses as travel is restricted, sure it would pick up again, but how many events would be needed to cripple airliners??? each time it is forgotten another attack occurs, and even IF not a single person dies the fears will increase. And its not exactly something you could stop....
Z.
Enough on this topic.
Sigh.
Its not the same issue, not even close as an analogy, how about instead, we ban crisps.
Thats right, crisps, totally inert you might think, well some of them now use foil wrappers to keep them fresh... What if it were discovered that crinkling them up would generate a radio signal that crippled the plane? I know you would advocate banning crisps at this point, but what does that achieve? Nothing, because a simple piece of foil could be used to bring the plane down. I'm not saying that the planes should be the equivalent of nuke-proof, I'm saying that they ought to be safe from party-poppers.
Why you seem to be saying its ok to have something as simple as this take down a plane I don't understand.
My point is this: You can now build a device that uses simple electronics to disable some safety systems onboard a plane. To me this is not acceptible, to you well it seems like it is. And to ban some devices that as a side effect generate this interferrance, and claim to have solved the problem???? Thats why face recognition at airports is a dud, its false security and its not worth doing.
Z.
Try to think of the larger picture.
Its possible to jam signals or drown them out. A truck with a decent signal generator and amp could drown out an airport's air-traffic control.
Now, lets say that there is a problem in a particular airport, a bomb threat or something so that the planes are stacked above it, now if someone should jam / drown out the air-traffic controller with a high Wattage signal, and at the same time use the spark-gap transmitter to scramble the collision avoidance, now where are you???
Yes its a doomsday scenario, but it requires a number of devices:
a bomb threat - telephone call
UWB devices, cheap personal stereo's and some cheap electrics.
Signal blocker... Take some standard radio gear and beef up the wattage, saturate the signal band. Use a directional antenna to improve the signal strength and to make tracking harder...
Use the signal blocker to trigger the UWB devices, and then you have a scenario..
Sure nothing might happen, but a well co-ordinated attack could easily cause some nasty accidents, especially if you rig it so that some extra flights are diverted to that airport before-hand...
The skills required are soldering and some knowledge of electronics.. These aren't criminal skills and the info you need is easily available on the net...
Its more than just a UWB on a single plane...
Doomsday, true, unlikely, true, impossible, false.
Z.
Does anyone else think that it should therefore be possible to create a small handheld device that say looks like a walkman/personal stereo, but contains an UWB transmitter? Activate it in a heavily traveled airspace and create chaos at best...
/. and that they couldn't have thought of it themselves :) In fact why bother being on the plane, have it in the baggage hold on a timer... It's not explosives, its a harmless walkman...
Rather than just try and ban the devices shouldn't they be working on methods of blocking the signals? Or altering the collision avoidance systems to cope with the interferrance?? Doesn't this smack of really bad shortsightedness?? Even if UWB is several years away, spark-gap transmitters ought to be homebuildable and with far more power than the average UWB transmitter.
I might be giving away ideas here, but doubt that terrorists read
Just a thought, these things crop up when people try one solution to a problem, but they are just trying to prevent it. And even though people say prevention is better than cure, cure is far more reliable.
Z.
P.S. Sorry to bring the 'terrorist' angle up again but this strikes me as a stupid thing to do, even if it never occurs. When you have people's lives at risk it ought to be cure, not a reliance on prevention.
Well you could, but there are reasons why this is a bad idea.
I think the exploding birds might cause an issue, and the chance of serious injury / death if something managed to reflect some of the energy, a metal fragment etc, or a plane was blown off course.... The reason the beam is so wide is to reduce the energy per metre squared to below safe levels, thus not hurting anything, BUT that increases the surface area needed to gather that same total energy.
Z.
Stunned that it weighs so little, especially when you consider that it has to have a tensile strength of at least 280 tonnes (at geosynch). Just to lift itself and cargo.
I looked into orbital tethers and sky-hooks a while ago, and the weight to strength ratio needed is massive. A metre of this stuff weighs in at 7.5 grams, and can hold 280 tonnes? Thats very strong. They may thicken it as the cable rises (since the greatest tension is held at the geosynch point) but they said it was only a few centimetres squared (at ground level).. I'm very impressed, but will be more so when you can see this tiny line shoot straight up.
Z.
Yes.
By the sounds of it there will be over 10 tonnes of tension on the base of the cable (twice the lift capacity at least), the weight of the floating platform will likely be in the tens of tonnes and easily counter balance this. The weight of the cable beyond geosynch orbit will provide this tension and that would mean that you could climb up it and the only change would be a reduction in the tension beneath you.. You could get away with having a large weight just beyond geosynch orbit, and in fact that would be how I would do it, since the centrifugal effect would mean that you would have a gravity of sorts.. Of course that means you'd need to put something up there or bring something into orbit.
The main use I can think of for this technology is power. Orbital power stations would be far more efficient and always on, but beaming that power down would be a nasty thing, nobody likes mile wide+ microwave beams, plus the realestate to recapture the huge beam is expensive. This orbital elevator could be used to pipe that power down to earth, and get re-distributed from there, and that would be a pollution free, cheap (after a while) way to power the earth. If it works I'd expect several larger scale projects to occur, likely land based.
As another point, mainly to the doomsayers about the cable breaking, the issue is where it will break.. if it breaks at the base it will simply leave the earth and not crash anywhere, only the bit below the break will fall to earth... The 'worst' case would be if it breaks at the geosynch point, then you have 36,000 km's of cable falling.. Luckily most of it would burn up, leaving only a small section (odd km of it) at the base to hit the sea.
Z.
Where to begin???
Point 1: Neo to attach to. Unnecessary. You can achieve the same thing with a really long teather and a 1 kg weight on the end. Did you not notice that the cable was 100,000 km long, when geosynch orbit is only 36,000 (miles or km I can't remember, but even if it is miles that would make it 57odd thousand km up, far less then the 100,00 required) the extra thousands of km are used to provide leverage and a decent ratio for the mass to be lifted.
Although I am curious to know what you mean by strong enough. All you need to do is get an object, in geosych orbit, move it to an outer orbit but keep it at the same angular velocity (how long it takes to orbit the earth) and the resulting centripetal force can be used to pull against when pulling up mass. 'Strong' neos aren't needed, a collection of cotton wool would do it, if there was enough and it was far enough out.
Point 2: Constant height. Not actually necessary, the water level is pretty flat (aside from tidal variations due to the moon and the sun) BUT the cable is under constant tension thus would forgive a certain amount of play. In fact the cable has to be at over 5 tonnes of tension at the base to be able to lift the mass required.
Point 3: Energy required for lift. Actually you are wrong again, the energy required is less. When you use a reaction engine fully half the energy required to boost you is wasted throwing mass out in the opposite direction. HOWEVER along with this is the fact that they are going to be using lasers to drive photovoltaic cells to drive electrical motors, and this could (in theory) be purely sunlight driven.
Point 4. Location. The ocean isn't too bad, a simple cargo ship deliver the cargo and it lifts. Sure its not rail or lorry but its good enough. Most of the oil the US needs is shipped via tankers, why can't a few satelites?
Point 5. Anti-gravity. (Ignoring the racist angle) this is an unproven experiment, and it should be noted that 2% is a little different to lifting the item into orbit.
As an aside, the cable itself will weigh in at a stunning 750 tonnes. Of that 480 tonnes (metric) will be above geo-synch orbit (assuming 36k km or should that be Mm???) and not likely to crash down.
I applaude them, but hope it does all work even though I have my doubts...
The tensile strength of the cable needs to be huge.. 7.5 kg per km, and that needs to hold around 270 tonnes, its a hell of a challenge....
Z.
Ahh but you signed up for it when you joined... Sheesh... :) Still they allowed you to 'opt-out' when you left...
Its impressive though that IBM's spam filters are so good, having seem friends of mines' IBM addresses on the web, they haven't received a single spam mail through to their account.. And yet my home address harvested from the same page now gets around 30 a day.. So some filtering software does work..
Z.
You'd be better off using the stuff they use to electrically heat car front windscreens..
This stuff is so fine that you can barely see it unless you look for it, BUT would work as a faradays cage, aslong as you connected it up properly..
Seen it on a Ford I had, I think BMWs have it aswell..
Z.
The main problem with acrylic / perspex cases is the lack of radiation shielding..
:)
Macroman from Bit-Tech.net suggested that the foil he uses on one of his cases (reflective unless internally lit) might block the radiation plus give a great effect.
If you place acrylic cases next to your TV or radio, then you can see the interferrence..
Also I remember reading that an open case / case window was screwing around with a remote garage opener..
Just a thought if anyone is planning to use it as a tv top box since it looks so nice
Z.
Technically it is a sound wave, I never mentioned the frequency, merely the amplitude, it could be running at 5kHz, I'm not saying its currently possible with our level of technology but in theory it would be possible. Yes you can say that it is best to model it as a wind, but at what point do you draw a line? Limits of human hearing?
I also wasn't talking about the device mentioned in the article, since it really isn't going to be able to create the necessary level of power. Especially since the ultrasonic wave's amplitude will need to be around the same level I believe to recombine to the necessary force. And its harder to create high frequency high amplitude sound than low frequency high amplitude sound. I merely was arguing that in theory it is possible to knock someone down with what would be classed as a sound wave.
As for it being impossible to create a sonic gun, I don't think so, very difficult, but you won't necessarily need to use explosives to generate it. As a point actually, explosives don't create true sound waves. The majority of explosives (not atomic) work by creating vast quantities of gas (normally CO2 or CO) in a very short space of time, thus you end up with a shockwave, this shockwave is a positive displacement of air, a high pressure wave. Whereas a soundwave doesn't actually move the air, the wave travels through the medium without moving the medium (as a net result; there is some movememnt as the wave travels, but it is on average zero movement). I was actually talking about a true soundwave, +x -x of the medium's pressure.
Conservation of momentum is not really a limiting factor, true its not going to throw the target 20 miles, and in fact, will literally only knock him down akin to a wave on a beach, pretty much on the spot because of the sudden changes in the directions of the force, pull towards the low pressure, pushed by the high pressure..
Z.
Sound can be focussed.
Sound can be reflected.
Sound can be refracted.
I was going to explain it all, but then I remembered a simple way to prove it to you.
Place your hands near your ears, like you were going to put them over your ears but hover them around 2 inches off. Now hiss. While hissing twist your hands.. You will notice an alteration in the volume as your hands pass a certain point, this is because the high frequency noise is bouncing off your hands and you are receiving more hiss.
This empirical test shows that sound can be reflected, and if it can be reflected then it can be focussed, and it probably can be refracted. (I know it can but I can't think of a simple test for it).
Sound is a number of waves travelling through a medium, air, thus although it is not a wave and a particle in the same sense as items in the electromagnetic spectrum, it does have a particulate medium to travel through.
And as a point how do you expect "to collect the DIFFUSED waves." if they cannot be reflected???
How do parabolic microphones work? Speakers with bass reflex ports??
Sound is a wave, sound can be reflected.
Echo, echo, echo, get the point?
Z.
Erm, not quite true, at least in one respect.
True yes, human bodies do not have strong resonance frequencies, and that's primarily because we are soft. Only our bones are particularly hard. As you vibrate innacuracies such as your breathing, blood being pumped all vary your 'resonant' frequency. Even moving your arm alters the standing wave you would produce, thus it would be incredibly difficult if not impossible to shatter someone (even their bones since they change according to the stresses and contact with other materials).
Having said that however, the assertion that it is impossible to 'knock someone over' with a sound wave is false. It is actually possible, and here's why:
Sound is nothing more than our brains interpreting compressions and refactions of the atmosphere. These waves can vary in frequency, hence the higher and lower pitched noises, and can vary in amplitutde, hence the louder and quieter noises. What these really are are 'walls' (concave-flat depending on the source) of high and low pressure air radiating from the sound source. Akin to waves in the sea, you have a trough, low pressure and a peak, high pressure. If you had a wave of sufficient amplitude you could be running from vacuum to 2 atmospheres (might actually be higher than that). This creates a wave scenario where you have a fast moving ~600MPH wall of air of a pressure difference of two atmospheres. Easily sufficient to knock someone down, its akin to jumping out of a plane doing 1200 MPH, it throws you back, fast.
The reason normal sound does not do this is that the amplitude is too small, even the loudest of concerts doesn't have the 'directed' power (noting that the aim is not to focus the power on someone, but to provide it to all the audience) necessary to knock someone down.
This is not going into the stun devices, but phasors cannot work anyhow, looking at the link the person who wrote the page seems to believe that they were based on laser technology, this causes a problem since it will just burn holes in people, that would stun me, but I'd likely die shortly afterwards. The link has very little to do with sonic based weaponry, which is a pity.
Z.
Not True.
If you gain a mod chip for a PS it generally does three things for you:
1) Allows you to play non-'original' disks. (A semi-dodgy area, fair use says a backup is permitted)
2) Allows you to play discs from other regions (No illegality here.)
3) Allows you to play DVDs from other regions. (Perfectly legal)
One of the selling points on a PS2 is that it plays DVDs, and hence you can factor in that cost of a DVD player when buying a PS2, and as pretty much ANYBODY in a country that does not fall into region 1 knows DVDs are somewhat more expensive there... Not mentioned the staggered release dates, region 1, then 6 months later the rest of the world.
Games are also 'zoned' in a similar manner, brought out eariler, different pricing, and in fact different games (well features I guess)..
Why companies playing in a global market should attempt to segment, purely for the purpose of increasing profit... If you import DVDs from the states to the UK you still pay the VAT, and hence the tax arguement doesn't really cut it with me. Some items really are value added for the zones, but so far I've only noticed this on cars, not Computer related items.
And so to sum this up, there are perfectly legal and legitimate reasons for installing / purchasing a mod chip. I'm not saying that everyone has these goals in mind when they buy or sell them, but I am saying that to tar everyone with the same brush is a little harsh, and wrong.
To reply to the quote in the parent: This was totally unrelated to the first sale principle, it was the selling of mod-chips (oh and those copied games). Once you have bought the hardware there is nothing illegal about altering it. Sure the DMCA may come into force if you circumvent copy-protection, BUT I'm not sure if that applies if you don't distribute the 'crack'. At least nobody will know since there will be no publicity.. If you buy a ps2, crush it and use it as a doorstop, you can, and there is NOTHING Sony can do about it, even if you publish it, hell that probably violates the DMCA since the copy-protection is circumvented... Hmm I wonder what happens to scrapped machines??
Sony (and Sega, MS, etc) want to stop this because traditionally Europeans (and other areas, sorry about the view - I'm from Europe) will tolerate much higher pricing than their American counterparts, thus better profit margins..
Z.
P.S. I believe PS2 Games are zoned, although I'm not 100% sure.