I've found that some things (water, water pipes, metal of any kind, walls to some extent, some metallised windows absorb/reflect the microwaves extensively. Sometimes you can move the base station so that it peeps around the edge of stuff, and then you can find good coverage over the whole building.
Also, try putting the aerial higher or lower, near a window or door may be good.
- find out if there's any interference
Some equipment, noteably, cordless phones; less likely microwave ovens (get your oven fixed if that's the case!) Bluetooth can also interfere.
- get better equipment
Ultimately I've found some equipment has poor range. You don't say what equipment you have. You may be able to modify the aerial on a base station, but try everything before doing that; it may make your equipment illegal.
I've found ranges of 100 ft or so in a building is quite achievable, although sighting of the base station is sometimes critical.
In that case, the high pressure area also pushing air downward is just a side effect, and doesn't directly affect the aircraft unless it is at a low altitude, right?
If you want to know how much lift an aircraft generates, measure what the overall momentum of air going down is; that's numerically equal to the lift. There is a direct relationship.
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Don't do it; he's a gray; he's trying to lull you into a sense of false security!
It's never safe to take off your tin foil hats!
I mean come on; how stupid do you think the tin foil hat wearers really are?
At high altitude, the air being forced down and the lift are two sides of the same coin. It's the same with fixed wing aeroplanes too. You HAVE to throw air down to stay in the air. The low pressure area is caused by the air above the wing curving to point at the ground. As it does this it speeds up and that reduces the pressure. But you also get high pressure air on the underside; and that's actually most of the lift, particularly at low speeds. Again, the high pressure is associated with turning the airflow towards the ground.
At low-moderate altitude you get ground effect; this greatly reduces the air flow and greatly increases lift. The aircraft acts more like a hovercraft, generating high pressure under the wing.
No it isn't. From Newtons third law, the fact that the helicopter is being forced up, means the air has to be forced down. It's an inevitable, and desirable consequence.
Yeah, ok, I blew that one, it cancels nicely. But by the same token, no extra energy is needed at 2000 ft underwater than 1000 ft underwater to go up or down; which was the whole point of my post really.
Unlike in true flight, where it doesn't require more energy to maintain an altitude of 2000 feet than 1000,
Yes it does, the air is thinner up there.
it takes incomparably more energy to maintain a depth of 2000 feet compared to 1000 if you're not using buoyancy control.
A submarine displaces its own volume of water, and has a lift proportional to the difference between its weight and the weight of that volume of water at that depth. The density of the sea water hardly varies between the surface and the bottom (the pressure goes wayyyyy up, but water is largely incompressible), so the buoyancy is nearly the same.
Therefore the amount of energy needed is largely the same also; independent of altitude, for a fixed volume submarine, since you're only really fighting buoyancy to go down.
Also, in flight a wing uses reduced air pressure above the curved top of the wing surface (Bernoulli's Principle) for most of its lift. Does anyone know if this effect applies in water? Intuitively it seems like it would not.
Gee, I don't know, mister; ever heard of a propeller? That's a set of wings that rotate under water. Get a clue.
Mark Shuttleworth already went there; he was extremely popular with the astronauts; something about helping fix all their broken (Microsoft) computer systems;-)
The weight of a segway is about ankle high. At worst its going to scoop you off your feet; the actual collision that matters is between the people; and runners go rather faster, and they are permitted on sidewalks; the segway's mass is too far below the waist to make a difference.
Sounds like it would be great in summer though, a cool breeze from moving through the air and not getting hot and sweaty from pedalling away like on a bicycle.
It makes little difference to the accident. Don't forget that the extra weight is near the ground, so the two people will collide, the person on the segway will stop, and the person hit will fly off at at most 12 mph. The segway won't contribute much, since the leverage to the struck person is poor from down at shin level, where most of its weight is.
The struck person will probably move bodily away, and probably fall over.
It should be quite comparable to being hit by a jogger; and no I don't think segway riders will necessarily be heavier than average people; segway riders will probably be car drivers who leave their car at home, or sell it. They may well get more exercise and end up leaner...
Nah, check out the other posters, it's slower than most runners, weighs less than most runners, is about as manoeuverable and stops on a dime.
Not only that but the center of mass is really low, so if it does hit someone, the person who is hit will end up on the pile of person, segway and passenger (kinda Karmic justice I suspect;-) ).
If you think you can hack together something that works (i.e. tested!), possibly with suboptimal performance, with a horrible schema etc. then do it; otherwise walk away.
If you've hacked something together you may well get more money to spruce it up afterwards; a working site may be upgradeable to a better schema or whatever, although it will cost. It sounds like the company doesn't care so much what it costs, so that might work.
But if you can't see any plausible way to do it right now, you should walk.
Well, setting up a firewall to do that isn't hard at all.
But there are some issues.
For example some legitimate traffic will enter an ISPs network from outside on its way somewhere else; you do NOT want to kill that traffic, and by the time it reaches the firewall on the way out, the packet contains no record of how it got there.
Depending on network topology you may still be able to do it of course, but you'd have to do it with some care.
You're missing the fact that the target isn't the game server, the game server is the weapon, the target is elsewhere e.g. www.slashdot.org;-( and there are tens of thousands of servers out there you can use simultaneously; so the users of the game server probably wouldn't notice.
In fact you're better off using multiple servers because that makes it harder to filter out at the firewall, if you're stupid enough to do this kind of attack that is.
No. This is the electronic equivalent of the pizza attack; you ring up pizza restaurants and order for someone else; they get swamped with pizzas.
This is the same except the pizza restaurants are the games servers (there's tens of thousands worldwide), and the address you give is any port on any machine worldwide. And it's particularly nasty because UDP packets don't throttle back, so all the bandwidth to that machine gets soaked up by this attack, and the machine spends most of its time just throwing away packets it can't understand.
If someone has your IP address, you are screwed; whatever game YOU are playing.
You can take the Shuttle's design and modify to solve problems and improve efficiency more coest effectively than building a brand new orbiter.
No. The cost of the shuttle is the wages of people working on it. The vehicle is designed to need lots of people, and it will remain so till it dies; because it is good for the politicians that way.
Slashdot Mirror
I've found that some things (water, water pipes, metal of any kind, walls to some extent, some metallised windows absorb/reflect the microwaves extensively. Sometimes you can move the base station so that it peeps around the edge of stuff, and then you can find good coverage over the whole building.
Also, try putting the aerial higher or lower, near a window or door may be good.
- find out if there's any interference
Some equipment, noteably, cordless phones; less likely microwave ovens (get your oven fixed if that's the case!) Bluetooth can also interfere.
- get better equipment
Ultimately I've found some equipment has poor range. You don't say what equipment you have. You may be able to modify the aerial on a base station, but try everything before doing that; it may make your equipment illegal.
I've found ranges of 100 ft or so in a building is quite achievable, although sighting of the base station is sometimes critical.
If you want to know how much lift an aircraft generates, measure what the overall momentum of air going down is; that's numerically equal to the lift. There is a direct relationship.
It's never safe to take off your tin foil hats!
I mean come on; how stupid do you think the tin foil hat wearers really are?
I'm pretty sure it still applies, since it is a thermodynamic effect that comes about at the molecular level- water will still experience it.
But as you say, the Coanda effect is pretty important, more so than the Bernouilli; but the ram effect under the wing is usually even more important.
At low-moderate altitude you get ground effect; this greatly reduces the air flow and greatly increases lift. The aircraft acts more like a hovercraft, generating high pressure under the wing.
No it isn't. From Newtons third law, the fact that the helicopter is being forced up, means the air has to be forced down. It's an inevitable, and desirable consequence.
Yeah, ok, I blew that one, it cancels nicely. But by the same token, no extra energy is needed at 2000 ft underwater than 1000 ft underwater to go up or down; which was the whole point of my post really.
Why not then? As far as I can see off-hand that's how it works.
Yes it does, the air is thinner up there.
it takes incomparably more energy to maintain a depth of 2000 feet compared to 1000 if you're not using buoyancy control.
A submarine displaces its own volume of water, and has a lift proportional to the difference between its weight and the weight of that volume of water at that depth. The density of the sea water hardly varies between the surface and the bottom (the pressure goes wayyyyy up, but water is largely incompressible), so the buoyancy is nearly the same.
Therefore the amount of energy needed is largely the same also; independent of altitude, for a fixed volume submarine, since you're only really fighting buoyancy to go down.
Also, in flight a wing uses reduced air pressure above the curved top of the wing surface (Bernoulli's Principle) for most of its lift. Does anyone know if this effect applies in water? Intuitively it seems like it would not.
Gee, I don't know, mister; ever heard of a propeller? That's a set of wings that rotate under water. Get a clue.
Mark Shuttleworth already went there; he was extremely popular with the astronauts; something about helping fix all their broken (Microsoft) computer systems ;-)
'Traction' wouldn't be enough to cause you any problems, anymore than it does when people 'sweep' peoples legs away using a martial art.
No it won't be concentrated.
So it's no worse than a jogger doing a flying kick to my shins with steel-toed boots?
It's probably about the same as being hit by a car at 12 mph, which if you think about it, isn't bad at all.
The weight of a segway is about ankle high. At worst its going to scoop you off your feet; the actual collision that matters is between the people; and runners go rather faster, and they are permitted on sidewalks; the segway's mass is too far below the waist to make a difference.
Sounds like it would be great in summer though, a cool breeze from moving through the air and not getting hot and sweaty from pedalling away like on a bicycle.
The struck person will probably move bodily away, and probably fall over.
It should be quite comparable to being hit by a jogger; and no I don't think segway riders will necessarily be heavier than average people; segway riders will probably be car drivers who leave their car at home, or sell it. They may well get more exercise and end up leaner...
Cool. I want one that can do 40 ;-)
Not only that but the center of mass is really low, so if it does hit someone, the person who is hit will end up on the pile of person, segway and passenger (kinda Karmic justice I suspect ;-) ).
You mean over 17 right?
If you've hacked something together you may well get more money to spruce it up afterwards; a working site may be upgradeable to a better schema or whatever, although it will cost. It sounds like the company doesn't care so much what it costs, so that might work.
But if you can't see any plausible way to do it right now, you should walk.
Actually, java is now 2-5x as fast anyway. The JIT compilers make a big difference. When Java came out they only had interpreters and they crawled.
I did wonder. Still, you are obviously vulnerable whilst online and posting to Slashdot ;-)
But there are some issues.
For example some legitimate traffic will enter an ISPs network from outside on its way somewhere else; you do NOT want to kill that traffic, and by the time it reaches the firewall on the way out, the packet contains no record of how it got there.
Depending on network topology you may still be able to do it of course, but you'd have to do it with some care.
In fact you're better off using multiple servers because that makes it harder to filter out at the firewall, if you're stupid enough to do this kind of attack that is.
This is the same except the pizza restaurants are the games servers (there's tens of thousands worldwide), and the address you give is any port on any machine worldwide. And it's particularly nasty because UDP packets don't throttle back, so all the bandwidth to that machine gets soaked up by this attack, and the machine spends most of its time just throwing away packets it can't understand.
If someone has your IP address, you are screwed; whatever game YOU are playing.
No. The cost of the shuttle is the wages of people working on it. The vehicle is designed to need lots of people, and it will remain so till it dies; because it is good for the politicians that way.