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Flight Attendants Want Stricter Gadget Rules Reinstated

leonardluen Re:We're ignoring them... (404 comments)

i was wondering that myself.

the wikipedia article on water landing lists about 30 commercial airplanes that either had to ditch or in some other way ended up in the water.

at least 2 of the planes didn't have any floatation devices at all.
and apparently this flight is what started all the safety demonstrations for over-water flights. because a bunch of passengers died after they panicked and refused to leave the plane after it had to ditch in the ocean ocean..

They feared the rough seas and the possibility of sharks and had refused to leave the sinking aircraft to board life rafts

though i don't really see how safety training would have made much of a difference for that, as i don't recall it normally covering rough seas or sharks.

about a week ago
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The Physics of Space Battles

leonardluen Re: Umm no (470 comments)

apparently the bigger threat to the A10 was flame-out of the engines due to the exhaust from the gun depriving them of oxygen. This had happened while in testing and so they had to add internal igniters to the engine that fire when the gun is fired to keep the engines burning.

so the idea is you send the platform towards the target from long distance to keep yourself safe. it is primarily un-powered and just coasting so the enemy can't detect additional heat or radiation from your thrusters to give away that the platform is coming. when it gets close it swivels with the gyros to correct any aim towards the target, which may have moved since you sent the platform, but hopefully now you are much closer to the target, and they have much less time to react. It then fires its gun. if the target is directly in front of you, then using your math you get a good about 1k shots off before you stop relative to the target. however even after that the velocity of your rounds are still sufficient to cause damage, and maybe you can fire an additional 500 rounds that are still lethal. the last of which would be traveling around 500m/s towards the target, of course this is all ignoring the loss of weight due to the ammo being fired

even if the target is directly to your side relative to your direction of movement you can probably get a good 500 shots off towards it at potentially lethal velocity. if on the other hand you have passed the target before you fire, then it is too late and there is possibly no point in firing as your rounds would not reach the target. so you just need to make sure you fire before this.

about three weeks ago
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The Physics of Space Battles

leonardluen Re: Umm no (470 comments)

oops, i guess i missed this part "but the complete weapon, with feed system and drum, weighs 4,029 pounds (1,828 kg)"

so the platform would might have to be up to 5k to 6k kg, which is around the size of a geostationary communication satellite.
but would then allow us to fire off 7k to 9k rounds before we stop the platform. the GAU-8 fires at 3900rpm, so this is only a 2 to 3 second burst.

about three weeks ago
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The Physics of Space Battles

leonardluen Re: Umm no (470 comments)

the GAU-8 fires a 0.69 kg round at a muzzle velocity of 990 m/s, the gun itself weighs 280kg we will use that as a starting point. according to a random website a "medium sized satellite" would be around 1000kg so lets use that for an estimate to the size of our entire thing to include electronics and such. so if my math is right each round fired would add about 0.683m/s of backwards velocity to the platform. say the platform was traveling towards the target at around 1000 m/s in the begining then you could fire off around 1500 rounds before the platform comes to a dead stop relative to the target. and the first rounds you fired would be traveling nearly 2k m/s towards the target.

Clearly the only way to resolve this argument would be for the USAF to let us borrow an A10 and fire the gun! not entirely sure what it would prove, but it would be fun.

.

about three weeks ago
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The Physics of Space Battles

leonardluen Re: Umm no (470 comments)

what is your point? if you have gyros to control orientation and aim you probably have computers and some sensors to aim. the gun platform is now much closer to the target than the original ship from where you had launched it, so it should also be much easier to hit the target now. the target will also have less time to react to the projectile and move out of the way now.

but to fire projectiles at a moving target you have to fire ahead of it so the projectiles and the target meet.

this is already a solved problem. we already do it on earth with patriot missile system. and some of the targets they take down are moving faster than they do.

the amount of thrust used to fire the projectiles that way will push your gun and whatever it's mounted to, backward with the exact same force.

umm...so you mean just like you see in the movies where the guy shooting the gun gets thrown across the room, just like the guy he shot at?

the gun platform will already have velocity towards the target. all it is doing is getting in closer to the intended target, correcting the aim, and then shooting a projectile smaller than itself. (bonus points if the platform itself also hits the target, but this isn't needed). yes there will be some kickback when you fire, but it doesn't necessarily matter since you don't care if the platform itself hits. you already have velocity towards the target any more you can add to the projectile is a bonus. in addition you could either add extra mass to the platform to help counteract this kick, or add rockets to it that fire off just before you fire the projectile so that you can impart the most velocity possible into the projectile towards the target.

and actually it might be good to calculate the charge so that once the projectile is fired, it takes all forward momentum away from the gun platform relative to the target and parks it right in front of the enemy, just being a nuisance in their way. though you would probably want to fry the electronics so they can't easily reload it and send it back.

about three weeks ago
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The Physics of Space Battles

leonardluen Re: Umm no (470 comments)

i would imagine the "missile" would contain gyroscopes so it can change orientation without using thrusters. For bonus points you could even make it look like a natural meteoroid, then when it gets close to its target it, it uses the gyroscopes to aim towards the target and can fire off a bunch of smaller projectiles designed to pierce the target's hull.

the radiation from thrusters is what is most likely to give you away, so this eliminates them entirely.

about three weeks ago
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Ask Slashdot: How To Keep Students' Passwords Secure?

leonardluen Re:OpenID (191 comments)

oops nevermind, guess i need my eyes checked. thought you had said take away their slashdot accounts.

about a month ago
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Ask Slashdot: How To Keep Students' Passwords Secure?

leonardluen Re:OpenID (191 comments)

That is just harsh, they will be mocked mercilessly when they have an 8 digit slashdot ID because you didn't let them signup for slashdot.

about a month ago
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Sci-fi Predictions, True and False (Video 1)

leonardluen Re:Star Trek Communicators (139 comments)

Seems the better edict would have been to have everyone change the color of their shirt.

"Hey these red shirts seem to anger aliens and make people clumsy, so lets start wearing green shirts instead!"

about a month ago
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Unpopular Programming Languages That Are Still Lucrative

leonardluen Re:In Theory (387 comments)

I don't know.

many Access project start like yours but then the business outgrows it, but then by the time you realize that you are then stuck with Access and have nowhere to go as it is doing all of your business logic and has turned into a monster.

  we originally moved everything to PHP and MYSQL, but have since converted most things to Java and MSSQL, with a little bit of C# here or there.

Our path probably isn't too helpful to you. i work for a university primarily developing internal applications. The majority of our decisions on what platforms to use are made based on what our slave labor (students workers) are capable of doing, so this is probably not necessarily what would work best for most businesses. The students may be cheap but they have extremely high turnover, as we can't keep them after they graduate. To be fair we do pay them and this is one of the highest paid student jobs available on campus. we have a short time to train them and get them productive before they leave, we have to work around their class schedules during the school year so we only get them part time, and considering they are still taking their CS classes they often know little to nothing when we get them. considering those limitations, i think we do quite well and the students that work for us get some valuable work experience that has helped them start their career after graduation.

about a month ago
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Unpopular Programming Languages That Are Still Lucrative

leonardluen Re:In Theory (387 comments)

I used to do Foxpro, it at least paid for my education. i would still pick it over MS Access on most days. we long ago converted everything out of foxpro and had never allowed anything that uses Access.

my favorite little side project that i had worked on in my free time was a sort of foxpro VM written in foxpro...yeah everyone thought i was crazy.

about a month and a half ago
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BBC: ISPs Should Assume VPN Users Are Pirates

leonardluen Re:Contacting BBC, via VPN (363 comments)

There is nothing wrong with them charging worldwide for their content, but using geolocation as your only means of authenticating whether the user has already paid is rather braindead.

about a month and a half ago
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How Scientific Consensus Has Gotten a Bad Reputation

leonardluen Re:Crichton is an idiot. (770 comments)

the point i am trying to make is that it takes more than one scientist to be "right". science is about repeatability. it takes multiple scientists repeating an experiment to advance our knowledge. if no one can repeat it, then that original scientist must have been wrong. When you have multiple scientist repeat an experiment and come to the same conclusion isn't that a consensus?

also there are any number of reasons that others may not be willing or able to repeat an experiment. if the subject matter is too controversial or had major hoaxes which dried up funding, such as maybe cold fusion for example, then even if someone does find something it is possible no one would be willing to verify those experiments as they may either view it as a waste of time or just bad for their reputation to be associated with looking into something that is so controversial and everyone "KNOWS" is wrong. it took a long time for the stigma around cold fusion to die down enough that scientists would begin looking at it again without fear of it being a black mark on their careers. now i am not saying i believe in cold fusion, just that it is an example where controversy can stop other scientists from conducting research into that subject.

about a month and a half ago
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How Scientific Consensus Has Gotten a Bad Reputation

leonardluen Re:Crichton is an idiot. (770 comments)

science is about repeatability. if only one investigator happens to be right, and no one else can repeat his experiment, then there will be no consensus even if he happens to be right. the prevailing hypothesis has stood the test of time and had multiple scientists repeat experiments to verify it, this is how the consensus forms.

Without a consensus most scientists will ignore it and go off to research something else, but then once in a while someone may come along and say "i wonder if this really is true?" and then they will run an experiment to try to confirm it. They will then either confirm it which reinforces the consensus, or will say hey these results don't fit, something is wrong here. they must then get other scientists on their side to repeat the experiment to confirm the results. if no one is interested in running those experiments then it doesn't really matter how right that scientist is, his discovery that the accepted hypothesis is wrong will be forgotten. and so consensus is very important to science

about a month and a half ago
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Robo Brain Project Wants To Turn the Internet Into a Robotic Hivemind

leonardluen Re:First step to SkyNet (108 comments)

1) history shows that humans absolutely destroy anything that ever threatens us.

2) robots don't need oxygen to breath.

instead of trying to kill humans it is most likely that robots will just leave the earth. humans won't easily be able to chase them so then the robots can live on their own and mine some asteroid or moon for resources and not have to compete with humans.

about 2 months ago
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Metamaterial Superconductor Hints At New Era of High Temperature Superconductors

leonardluen Re:150 kelvin = -189.67 F (39 comments)

if you are converting miles to 16ths of an inch you are doing something wrong.

really there isn't much need most of the time to convert between miles and inches or even feet and miles. the only real reason for that is to compress the number when you write it down. there is nothing stopping you from using deca-feet or kilo-feet.

typically when you are working in miles you aren't measuring down to the foot. so you would say something is 3.5 miles not 3 miles and 2640 feet or 3 miles and 880 yards.

the imperial system is designed around construction. using either feet or yards as our base unit for construction we can easily divide it into many different factors using inches. want something to be 1/3rd of a foot? easy that is 4 inches. now try doing that with metric.

really the imperial system (for distance) has multiple different measurement scales it just so happens that we designed them so we can easily scale between them. metric only has one. the meter with multiple prefixes we can attach to it. i will grant you that metric is far better for most scientific measurements. and when you get to relativistic speeds and stellar distances the imperial units mean nothing to me, i need to see it in metric to get a proper sense of scale.

now i am not by any means against metric, i just don't loath the imperial system.

however at relativistic speeds and stellar distances your precious metric system sort of breaks down. how many kilometers in a light year? you can use a calculator, and good luck. :P

*well i guess light year isn't really a metric unit but it is a commonly used scientific unit of measure, and does not easily convert to meters.

about 2 months ago
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Hackers Claim PlayStation Network Take-Down

leonardluen Re:progress (97 comments)

i agree with you.

how hard is it to put up a damn network? and then i don't have to put up with these bastard lizard pricks ruining everyones fun.

about 2 months ago
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WikiLeaks' Assange Hopes To Exit London Embassy "Soon"

leonardluen Re:Diplomatic pouch? (299 comments)

Too bad the venezuelan's don't have anyone to smuggle out...isn't he at the Ecuadorian embassy?

about 2 months ago
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Daimler's Solution For Annoying Out-of-office Email: Delete It

leonardluen Re:They are clueless... (232 comments)

And I do...just trying to give a tip that some people may find useful

it's also generally not a good idea for your manager to think "damn it does he ever come to work?" if you wait until Monday morning to turn off the auto reply and he often sends emails before it gets turned off in the morning, he may see it and mistakenly think you still aren't there. turning it off Friday evening (assuming you took the previous week off) means 3 less days of advertising you are a no good slacker that is always on vacation...unless your manager typically expects you to respond to emails on the weekend, or prior to the time you arrive to the office in the morning,

about 2 months ago
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Daimler's Solution For Annoying Out-of-office Email: Delete It

leonardluen Re:They are clueless... (232 comments)

Why not have the auto-reply end at the end of your normal business hours the previous work day? typically no one is expecting you to work then anyway and then on Monday morning before 9am they aren't still getting the auto-replies.

about 2 months ago

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