thats truly amazing how Jack Valenti has no clue about the position he is taking.
Not at all. He just doesn't care about the consequences to engineers/tinkerers. This illustrates his attitude rather well: "Let's say there are a thousand. But there are 284 million people in this country. You can't have public policy that is aimed at 100,000 people when the other multi-multi-millions are also involved. You can't do it that way."
Of course, he's set up a false dichotomy (100,000 engineers vs. 284 million Americans, when it really should be 100,000 engineers vs. ~100 major stockholders).
...is that one of the primary reasons certain other countries are able to "do it for less" is that they don't have the same labor laws, the same environmental protection laws, and the same workplace safety regulations. It took a hundred years of political activism and organization to achieve such things as the five-day work-week, OSHA regulations, the EPA, the clean air act, minimum wage laws, collective bargaining rights and Social security. These are all either things that make the middle class, or a decent life at all, possible. "Outsourcing" has become a way for managment to bypass all of that and bring us back to the heady days of laissez-faire capitalism. That may be great for the capitalist, but it sucks for everyone else.
Sure, from the safety of the upper class, and with most of your income being from investments, outsourcing looks great - all that cheap stuff available at Target, eh? But if you're 50, have two kids and a mortgage, and happen to, say, be an engineer for a telcom, hearing that your getting laid off "will be good for the American economy in the long run" isn't much solace.
I just moved to Boston from California, and I have to say that while the MIT/Harvard tech factor is indeed great, there are some things that took getting used to. Like the fact that the roads were designed by cows, laid out to confuse the redcoats, and are in a PATHETIC state of constant disrepair. It's truly amazingly bad.
Oh, and the corruption. The still have mob hits around here. West-coaster that I am I thought the mob was just De Niro and Danny Devito being funny. But no - last month a guy got whacked not too far from where I live...
And don't even get me started on the cops. I love how no matter how small the job, you will guaranteed see five guys standing around watching a guy with a backhoe do the actual work. Two of those guys will be cops of the donut-eating persuasion.
There used to be a picture on the web that was really neat: it was a long-exposure taken pointing toward the Elephants Foot. During the exposure a guy carrying a flashlight walked up to it and took a sample - you could see him all smeared out.
But I can't find the picture anymore, even on with Google..
If that's uranium slag, wouldn't it expose the film, preventing the picture from being taken?
Not necessarily. It depends on the activity level, particularly in highly penetrating types (neutrons and gammas). It would appear that after a few years (this was taken in the late 80s) the fuel had cooled enough (activity-wise) that it could be approached briefly. They talk of dose rates of 30 rem for the guy who took this picture. He also approached it close enough to get a sample. I kid you not.
I will admit that along with every other geek on/. I'm madly in love with this hot, hot biker chick. I guess I'm glad she didn't take this picture. Yes, that's a chunk of the reactor fuel itself.
people do benefit from the existence of organized society, and so it should be a duty to help protect said society."
What about those of us who neither benefit from nor desire it? Why force us to work for what you want?
I find it hard to believe you haven't benefitted from modern society. Have you ever taken advantage of modern medicine (even been vaccinated)? Do you live in a house? Do you use computers? Do you eat food grown by someone other than yourself? Do you carry a gun at all time to protect you and yours from roving groups of people bent on taking all you own? (ecpet the IRS of course:).
Then ask how much of a "free society" it is if people are forced to pay for it against their will.
There is a small difference. You pay income tax as a fraction of money you make. You aren't forced to pay taxes - just don't have any income. You are forced to serve in a draft (if we had one).
That being said, I do think a draft would be a good thing for two reasons: 1) people do benefit from the existence of organized society, and so it should be a duty to help protect said society. 2) If the sons and daughters of everyone were in harms way maybe we'd be less prone to imperial adventures.
Dose-response curves for radiation are actually somewhat controversial, at low levels. Read this for an interesting discussion. I've read in a Science (the magazine) article (sorry. forgotten the reference) that many researchers have given up on finding epedemiological effects from Chernobyl and are starting to look at other sites with worse (!) contamination, such as Mayak. That was the site of Soviet bomb-plutonium production, and there was apparently more contamination over a larger area from that. Who the fsck knew?
Much of the radiation in Cherobyl is, however, gamma. Which is very very bad. I believe it is apolitical.
Gamma is very penetrating, yes. But if you'd read the article you'd have seen the map and the radiation counter both showing dose rates on the order of 100 micro-roentgen/hr; that's less than 1 rem/year, and only slightly above natural background radiation levels. She said that those rates increase by a factor of 4-5 if you go off the road. I conclude then that a) it's smarter to stay on the road, b) these does rates are not "very, very bad" by any reasonable stretch of the imagination, and c) the only way you could be in serious peril is if there was an additional source of radiation exposure. Since she'd mentioned dust indoors, that's what I figured you were talking about.
TMI would have failed safe, except for incorrect operator intervention.
TMI did fail safe. You had a partial meltdown with only very limited release of short-lived radiactivity (Iodine-131, half-life 8 days). No deaths or injuries.
It woudn't have failed at all if it hadn't been for incorrect operator intervention.
You sound as if you are thinking that any radiation is bad or that radiation itself is bad.
It is. That is exactly what I am saying. In another example of me knowing more about this than you, there is NO safe level of exposure to ionizing radiation, natural or not. It isn't like a chemical or biological exposures where there are minimum affective doses. ANY radiation passing through your body has the potential to mutate that one single unlucky cell into a cancer cell.
Slow down there cowboy. Your cells have mechanisms in place to repair DNA. In fact, every second of every day your cells are getting some small amount of DNA damage from chemical byproducts of your metabolism (free radicals), UV radiation, and natural background radiation. There is some probability that a strand break can occur and not be repaired, and that can sometime lead to cancer.
But the fact is that you can get cancer just from living and breathing (ie. your metabolism). It's not at all clear that any additional dose of radiation is necessarily dangerous. In fact, there is some evidence that radiation exposure activates protective mechanisms in cells to improve DNA repair - look up "radiation hormeisis". Your statement about no minimum damage threshold is not on a very firm scientific basis; it is an assumption made by regulatory agencies who are trying to be conservative, not a scientific fact.
Dose/mortality rates used in setting health standards are based on extrapolation from survivors of Horoshima and Nagasaki. You have to understand that the doses and dose rates they received are 5-10 orders of magnitude greater than the rates you are likely to encounter walking around Chernobyl today. As any decent scientist will tell you, when you extrapolate a linear trend across that many orders of magnitude, you are basically just making shit up.
Since there are trillions of neutrons per m3 in Chernobyl
I call bullshit. That statement tells me that you are talking out your ass. There are NO neutrons anywhere except deep in the remainder of the core itself, where you still have fissile material. What you have in the surrounding area is alpha, beta and gamma radiation. Neutrons are produced by fission, and you don't have a trillion fissions/sec/m3 in the area. That would be producing something like 30 Watts per cubic meter; the place would be HOT, thermally. It isn't, so I doubt your number pretty strongly.
According to her maps the dose rates were something like 80 micro-roentgen/hr. That's about
700 millirem/year. Natural background radiation levels are typically 300 milliorem/yr, but can be up to 15,000 millirem/year.
there are different types of radiation and the type of radiation at Chernobyl is the really, really bad kind.
How so? Becuase it is Communist? I THINK you mean that there is a lot of alpha-emitting dust around, which is indeed not good to breathe. But I think she pointed out that unless you went indoors, there wasn't actually much dust. That was 18 years ago - a lot of the material gets buried in that time, because it's not particularly biologically active (i.e. doesn't get incorporated into plants - there aren't many proteins with americium in the active sites). The stuff that does get incorporated, such as strontium (which displaces calcium), is not an alpha emitter.
All this being said, I don't think you should be farming in the dead zone. But a few trips through on a motorbike is really no big deal.
As much as this sounds pretty cool, I have some problems with it. Or rather, I had some problems with the last paper of their that I read, and from reading the press release it doesn't sound like they've addressed them.
Simply put, fusion is extremely temperature sensitive. The fusion rate goes as something like the 12th power of the temperature. In their paper they said that the peak temperature of the bubble depended on the temperature of the liquid, with colder liquid leading to higher peak pressure and temperatures - the neutrons only appeared with the liquid being cooler than 20 deg C or so. Unfortuately for them, they claim their equipment would allow only a relatively modest cooling (like -10 deg C or something). Now, it would seem to me that the first thing they could do would be to get a heavy-duty glycol chiller and cool that sucker down to -50 C. If the peak temperature changes by only 10% the fusion rate would go from bareley detectable to kilowatts and they wouldn't have to argue. The fact that they haven't done this is worrisome.
Second, they are doing D-D fusion. But if they would just bother to add a but of tritum they could do D-T fusion. As D-T fuses at much lower temperatures again they have a simple experimental change that would make for a HUGE increase in fusion output. If they just did either of these they wouldn't have to be arguing back and forth about a few neutrons; their biggest worry would be avoidning lethal doses of neutrons, and how to spend all that Nobel money.
Uh, if I just dropped $10000 on a new car, I get rather pissed off at the suggestion that within a few months a I need to start paying some not-insignificant amount of money a month just so my car won't catch fire or die.
I don't know about you, but the cars I buy tend to run 100,000 miles before they need major maintenance. Gas, oil change etc is one thing. But I don't have to subscribe to anything.
And the fact that Linux boxes pretty much don't suffer from viruses does pretty much show that you can make a machine that way. Just like the Japanese cars showed everyone what pieces of crap American cars were.
Yes, AFAIK most computer users are running with expired antivirus subscriptions. Isn't it sad that people behave the way they do?
Uh, if I just dropped $1000 on a new computer, I get rather pissed off at the suggestion that within a few months I need to start paying some not-insignificant amount of money a month just so the damned thing won't catch a virus and die.
Funny, I don't recall having to subscribe to a freakin' virus protection scheme with my Linux box.
Fascinating post. You sound like you have a pretty good idea about radar. I only have one quibble....
First off, to scan the image, the transceiver's antenna would have to be scanned - physically moved around - at the same speed as the desired refresh rate of the image.
At the bottom of the article he mentions that these things are used as a phased array. You don't have to mechanically scan the antenna. This allows you very rapid switching. As for rates, lets say that you want a 1k by 1k image at 10 Hz. That's a pixel rate of 10 MHz, or 100 ns dwell time per pixel. That gives you a 50-ft range. Probably not sufficient, but close. You could very likely have multiple T/R beams simultaneously, as long as you are clever about sidelobe supression.
That being said, you are right about issues with gain and calibration. It's unclear from the post what frequency this thing works at, but they did mention 24 GHz. If that's the radar frequency, then won't you have some significant reflections off of people? This is really mm-wave radar...
By the way, I'd tought that passive imaging mm sensors were the next big thing; there is work on them for aircraft, I know. Maybe you could adapt this silicaon technology to that and make mega-pixel imaging mm arrays..?
i do not believe that the claim is being made that this is a perpetual motion machine - only that it would require vastly less energy than current technology based upon fossil fuels.
So does sailing. But you are at the mercy of the winds.
remember conservative fields? there is no net loss/gain of energy. in this case gravity is the conservative field.
Yes, I know that you can move perpendicular to the gravity vector without doing any work, but that isn't really what he's proposing. He is going up and down, trading potential energy in the form of altitude and compressed gas against kinetic energy. This trade is somehow supposed to allow him to do work against, say, prevailing winds blowing away from where you want to go. That's getting something for nothing. (your thermo prof says "bad!").
In addition, that trade cannot be 100% efficient, as your friend Carnot figured out a few 100 years ago. There will be losses, which means that your cycle will eventually peter out. That's the 2nd law.
His trade back and forth is reminiscent of a heat engine, but replacing a temperature gradient with a gravity field. As you pointed out, gravity is a conservative field, so there isn't a net energy flow you can tap into.
That being said, you could make use of prevailing winds to get you where you want to go just like current balloons do. But that's no great innovation.
now TRUE, there should be some small loss of energy due to friction, BUT the idea is to use some of that to restore the buyancy.
No. You can't make use of "losses" to restore energy. Those losses come from friction, which ultimately ends up as low-grade heat in the air you passed through. Going against the wind in any degree takes work, which requires energy, which has to come from somewhere. You can't just take that energy out of thin air. THough if you want to give money to some guy who says you can. be my guest.
Yes, and it is possible to travel along with wind currents in a regular hot-air balloon, all the way around the world if you're so inclined. However, he is proposing something different, which is that you use "gravity" to provide free propulsive power in a repeatable cycle. That's not going to work.
I mean, I can fill a ballon with helium, and it will rise without power.
But you can't come back down again unless you compress the helium (which takes work). You could jettison it, but then you'd have to do work to get more helium.
This scheme sounds a bit too much like a perpetual-motion machine. He talks about using energy generated by a wind turbine driven during the glide to alter the buoyancy... IF he'd talked about using, say, solar power to do so, I might believe this was something that at least didn't violate the 2nd law of thermodynamics. But he appears to be claiming he needs no external energy input. That's total crap,
and I'm surprised more/. people haven't jumped all over that point.
I mean seriously, didn't anybody take intro phyics in school? If you learned nothing else, you should have learned that you can't get something for nothing. Anybody who says otherwise is selling something worth nothing.
Those only work once the warheads have seperated from the launch vehicle. The solution? Target the launch vehicle *before* the warheads deploy.
Easier said than done; assuming we're talking about a Russian ICBM field the only way to get close enough is to be in orbit (you need to be within a few hundred km, and even then you only have 15-30 seconds decision time). This means literally thousands of interceptor satellites in low-Earth orbit (laser or kinetic warheads - it doesn't make much difference). That's pretty challenging, as these are not small satellites either. For comparison the GPS network is 24 sats; given that satellites in low-earth orbit re-enter fairly regularly (residual atmospheric drag), we'd be talking about lofting something like the equivalent of the entire GPS network every month.
And that's assuming you could actually build a laser or interceptor that would work reliably - and that's by no means a given.
And that's assuming the opponent didn't start his attack by wiping out all the interceptor satellites that are in range of the launch field (they all have to be in orbit, and will thus be known and tracked).
Remember, "buying the defences", especially when you have the element of surprise, is a technique that usually improves the chances of the offence greatly.
Look, no defense system is perfect, and noone ever claimed missile defense is a panacea. But it's better than sitting around, doing nothing to protect ourselves.
Didn't Reagan make exactly that claim? Anyway, your argument sets up a false dichotomy. Would the required 5% of GDP be better spent doing something else? Maybe the money should be used in anti-smuggling and border security ops? Or maybe, just maybe, we could stop trying to fsck over the rest of the world so maybe, just maybe, they'd be less inclined to lob ICBM's our way...
Just like the best lock will only slow down the best thief, not stop him, so too will the best defensive system only reduce the amount of damage done by the best offensive system. The goal is to increase our country's chance of survival
When the Soviets have enough nukes to personally provide a few kiltons to every man, woman and child in the U.S., it really doesn't matter if we could knock down 10, 50 or even 500 warheads.
With 10,000 ICBM warheads (MIRV's, remember) and 30,000 tactical ones, the acceptable leakage rate has to be so rediculously small that it's surely wasted effort. I've seen professional assessments showing that 20-100 hits would be more than sufficient to destroy the U.S. as a national entity, killing 30 million people in the process.
You are thinking like a military guy, where even a defence that is 50% effective is worthwhile because it forces the enemy to double his effort. But when it comes to strategic nuclear war, the difference between 2 and 4 warheads/aimpoint is pretty immaterial.
Do you honestly think Russia can build enough decoy ICBMs to counter the number of interceptors we could assemble?
Not decoy ICBM's. Balloon decoys. And hell yes.
You can put ~100 of them on each booster because they are little more than balls of mylar. Look, it's sooo much easier to build a mylar baloon than an anti-missle interceptor that a few orders of magnitude in GDP just doesn't fscking matter. You may feel superior to the Russkies, but fact is that they have enough resources to build enough ICBM's that the U.S. simply COULD NOT defend against them.
It's really that simple. And getting back to the original point, back in the 80's before the Soviets collapsed, they definitely had the resources to build an ICBM force that we could not defend against. No resonable person - even current SDI advocates - talks about defending against 1000+ incoming ICBMs, decoys or no decoys. All the current system is supposed to do is protect against North Korea and their 2 ICBM's. (In actuality the idea is to force the Chinese to spend real $$$ on more ICBMS so we can spend them into the ground the way we did the Soviets; those cheap bastards have been getting away with less than 100 ICBM's until now! Flawed logic for various reason we can go into later.)
And I haven't even started talking about counter-countermeasures other than decoys. You've got maneuvering warheads and buses, you've got chaff & jammers, you could set off a few nukes in space (completely wiping out any radar visibility for hours on end), you could have depressed-trajectory SLBM launches against the missle-defence sites, or you can have fast-boost ICBM's where the intercept time is very short.
Or you could just smuggle the damned things into downtown NY, LA and DC and be done with it, missile defence or no missle defence.
But like I said, it's only a question of scale, and none of those hurdles are insurmountable.
No, not really. The problem with intercepting an ICBM is above all one of decoys. The radar and IR sensors see an incomning cloud of 100 identical shiny, round objects. One of them contains a warhead. Which do you hit? Given that it's MUCH easier to build a decoy than an interceptor, that is a game that you can't win (assuming equal resources going in - which against the Russkies is a reasonable bet).
Correction, levels haven't doubled. They've gone from 260 ppm to 360 ppm. The doubling is expected sometime this coming Century. The rest of the point still stands, however.
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Not at all. He just doesn't care about the consequences to engineers/tinkerers. This illustrates his attitude rather well: "Let's say there are a thousand. But there are 284 million people in this country. You can't have public policy that is aimed at 100,000 people when the other multi-multi-millions are also involved. You can't do it that way."
Of course, he's set up a false dichotomy (100,000 engineers vs. 284 million Americans, when it really should be 100,000 engineers vs. ~100 major stockholders).
Sure, from the safety of the upper class, and with most of your income being from investments, outsourcing looks great - all that cheap stuff available at Target, eh? But if you're 50, have two kids and a mortgage, and happen to, say, be an engineer for a telcom, hearing that your getting laid off "will be good for the American economy in the long run" isn't much solace.
Oh, and the corruption. The still have mob hits around here. West-coaster that I am I thought the mob was just De Niro and Danny Devito being funny. But no - last month a guy got whacked not too far from where I live...
And don't even get me started on the cops. I love how no matter how small the job, you will guaranteed see five guys standing around watching a guy with a backhoe do the actual work. Two of those guys will be cops of the donut-eating persuasion.
Not necessarily. It depends on the activity level, particularly in highly penetrating types (neutrons and gammas). It would appear that after a few years (this was taken in the late 80s) the fuel had cooled enough (activity-wise) that it could be approached briefly. They talk of dose rates of 30 rem for the guy who took this picture. He also approached it close enough to get a sample. I kid you not.
What about those of us who neither benefit from nor desire it? Why force us to work for what you want?
I find it hard to believe you haven't benefitted from modern society. Have you ever taken advantage of modern medicine (even been vaccinated)? Do you live in a house? Do you use computers? Do you eat food grown by someone other than yourself? Do you carry a gun at all time to protect you and yours from roving groups of people bent on taking all you own? (ecpet the IRS of course :).
There is a small difference. You pay income tax as a fraction of money you make. You aren't forced to pay taxes - just don't have any income. You are forced to serve in a draft (if we had one).
That being said, I do think a draft would be a good thing for two reasons: 1) people do benefit from the existence of organized society, and so it should be a duty to help protect said society. 2) If the sons and daughters of everyone were in harms way maybe we'd be less prone to imperial adventures.
Much of the radiation in Cherobyl is, however, gamma. Which is very very bad. I believe it is apolitical.
Gamma is very penetrating, yes. But if you'd read the article you'd have seen the map and the radiation counter both showing dose rates on the order of 100 micro-roentgen/hr; that's less than 1 rem/year, and only slightly above natural background radiation levels. She said that those rates increase by a factor of 4-5 if you go off the road. I conclude then that a) it's smarter to stay on the road, b) these does rates are not "very, very bad" by any reasonable stretch of the imagination, and c) the only way you could be in serious peril is if there was an additional source of radiation exposure. Since she'd mentioned dust indoors, that's what I figured you were talking about.
TMI did fail safe. You had a partial meltdown with only very limited release of short-lived radiactivity (Iodine-131, half-life 8 days). No deaths or injuries.
It woudn't have failed at all if it hadn't been for incorrect operator intervention.
It is. That is exactly what I am saying. In another example of me knowing more about this than you, there is NO safe level of exposure to ionizing radiation, natural or not. It isn't like a chemical or biological exposures where there are minimum affective doses. ANY radiation passing through your body has the potential to mutate that one single unlucky cell into a cancer cell.
Slow down there cowboy. Your cells have mechanisms in place to repair DNA. In fact, every second of every day your cells are getting some small amount of DNA damage from chemical byproducts of your metabolism (free radicals), UV radiation, and natural background radiation. There is some probability that a strand break can occur and not be repaired, and that can sometime lead to cancer. But the fact is that you can get cancer just from living and breathing (ie. your metabolism). It's not at all clear that any additional dose of radiation is necessarily dangerous. In fact, there is some evidence that radiation exposure activates protective mechanisms in cells to improve DNA repair - look up "radiation hormeisis". Your statement about no minimum damage threshold is not on a very firm scientific basis; it is an assumption made by regulatory agencies who are trying to be conservative, not a scientific fact.
Dose/mortality rates used in setting health standards are based on extrapolation from survivors of Horoshima and Nagasaki. You have to understand that the doses and dose rates they received are 5-10 orders of magnitude greater than the rates you are likely to encounter walking around Chernobyl today. As any decent scientist will tell you, when you extrapolate a linear trend across that many orders of magnitude, you are basically just making shit up.
Since there are trillions of neutrons per m3 in Chernobyl
I call bullshit. That statement tells me that you are talking out your ass. There are NO neutrons anywhere except deep in the remainder of the core itself, where you still have fissile material. What you have in the surrounding area is alpha, beta and gamma radiation. Neutrons are produced by fission, and you don't have a trillion fissions/sec/m3 in the area. That would be producing something like 30 Watts per cubic meter; the place would be HOT, thermally. It isn't, so I doubt your number pretty strongly.
According to her maps the dose rates were something like 80 micro-roentgen/hr. That's about 700 millirem/year. Natural background radiation levels are typically 300 milliorem/yr, but can be up to 15,000 millirem/year.
there are different types of radiation and the type of radiation at Chernobyl is the really, really bad kind.
How so? Becuase it is Communist? I THINK you mean that there is a lot of alpha-emitting dust around, which is indeed not good to breathe. But I think she pointed out that unless you went indoors, there wasn't actually much dust. That was 18 years ago - a lot of the material gets buried in that time, because it's not particularly biologically active (i.e. doesn't get incorporated into plants - there aren't many proteins with americium in the active sites). The stuff that does get incorporated, such as strontium (which displaces calcium), is not an alpha emitter. All this being said, I don't think you should be farming in the dead zone. But a few trips through on a motorbike is really no big deal.
Simply put, fusion is extremely temperature sensitive. The fusion rate goes as something like the 12th power of the temperature. In their paper they said that the peak temperature of the bubble depended on the temperature of the liquid, with colder liquid leading to higher peak pressure and temperatures - the neutrons only appeared with the liquid being cooler than 20 deg C or so. Unfortuately for them, they claim their equipment would allow only a relatively modest cooling (like -10 deg C or something). Now, it would seem to me that the first thing they could do would be to get a heavy-duty glycol chiller and cool that sucker down to -50 C. If the peak temperature changes by only 10% the fusion rate would go from bareley detectable to kilowatts and they wouldn't have to argue. The fact that they haven't done this is worrisome.
Second, they are doing D-D fusion. But if they would just bother to add a but of tritum they could do D-T fusion. As D-T fuses at much lower temperatures again they have a simple experimental change that would make for a HUGE increase in fusion output. If they just did either of these they wouldn't have to be arguing back and forth about a few neutrons; their biggest worry would be avoidning lethal doses of neutrons, and how to spend all that Nobel money.
I don't know about you, but the cars I buy tend to run 100,000 miles before they need major maintenance. Gas, oil change etc is one thing. But I don't have to subscribe to anything.
And the fact that Linux boxes pretty much don't suffer from viruses does pretty much show that you can make a machine that way. Just like the Japanese cars showed everyone what pieces of crap American cars were.
Uh, if I just dropped $1000 on a new computer, I get rather pissed off at the suggestion that within a few months I need to start paying some not-insignificant amount of money a month just so the damned thing won't catch a virus and die.
Funny, I don't recall having to subscribe to a freakin' virus protection scheme with my Linux box.
First off, to scan the image, the transceiver's antenna would have to be scanned - physically moved around - at the same speed as the desired refresh rate of the image.
At the bottom of the article he mentions that these things are used as a phased array. You don't have to mechanically scan the antenna. This allows you very rapid switching. As for rates, lets say that you want a 1k by 1k image at 10 Hz. That's a pixel rate of 10 MHz, or 100 ns dwell time per pixel. That gives you a 50-ft range. Probably not sufficient, but close. You could very likely have multiple T/R beams simultaneously, as long as you are clever about sidelobe supression.
That being said, you are right about issues with gain and calibration. It's unclear from the post what frequency this thing works at, but they did mention 24 GHz. If that's the radar frequency, then won't you have some significant reflections off of people? This is really mm-wave radar...
By the way, I'd tought that passive imaging mm sensors were the next big thing; there is work on them for aircraft, I know. Maybe you could adapt this silicaon technology to that and make mega-pixel imaging mm arrays..?
Like I said, if his scheme included solar panels, or soaring on thermals, then I'd believe it. But it doesn't so I don't.
So does sailing. But you are at the mercy of the winds.
remember conservative fields? there is no net loss/gain of energy. in this case gravity is the conservative field.
Yes, I know that you can move perpendicular to the gravity vector without doing any work, but that isn't really what he's proposing. He is going up and down, trading potential energy in the form of altitude and compressed gas against kinetic energy. This trade is somehow supposed to allow him to do work against, say, prevailing winds blowing away from where you want to go. That's getting something for nothing. (your thermo prof says "bad!").
In addition, that trade cannot be 100% efficient, as your friend Carnot figured out a few 100 years ago. There will be losses, which means that your cycle will eventually peter out. That's the 2nd law.
His trade back and forth is reminiscent of a heat engine, but replacing a temperature gradient with a gravity field. As you pointed out, gravity is a conservative field, so there isn't a net energy flow you can tap into.
That being said, you could make use of prevailing winds to get you where you want to go just like current balloons do. But that's no great innovation.
now TRUE, there should be some small loss of energy due to friction, BUT the idea is to use some of that to restore the buyancy.
No. You can't make use of "losses" to restore energy. Those losses come from friction, which ultimately ends up as low-grade heat in the air you passed through. Going against the wind in any degree takes work, which requires energy, which has to come from somewhere. You can't just take that energy out of thin air. THough if you want to give money to some guy who says you can. be my guest.
Yes, and it is possible to travel along with wind currents in a regular hot-air balloon, all the way around the world if you're so inclined. However, he is proposing something different, which is that you use "gravity" to provide free propulsive power in a repeatable cycle. That's not going to work.
But you can't come back down again unless you compress the helium (which takes work). You could jettison it, but then you'd have to do work to get more helium.
This scheme sounds a bit too much like a perpetual-motion machine. He talks about using energy generated by a wind turbine driven during the glide to alter the buoyancy... IF he'd talked about using, say, solar power to do so, I might believe this was something that at least didn't violate the 2nd law of thermodynamics. But he appears to be claiming he needs no external energy input. That's total crap, and I'm surprised more /. people haven't jumped all over that point.
I mean seriously, didn't anybody take intro phyics in school? If you learned nothing else, you should have learned that you can't get something for nothing. Anybody who says otherwise is selling something worth nothing.
It, actually. I'm a highly advanced piece of code running on some big iron that would make you pee your pants.
(actually, I'm a fruit of an illicit union bewteen M-X zippy and M-x pinhead).
Easier said than done; assuming we're talking about a Russian ICBM field the only way to get close enough is to be in orbit (you need to be within a few hundred km, and even then you only have 15-30 seconds decision time). This means literally thousands of interceptor satellites in low-Earth orbit (laser or kinetic warheads - it doesn't make much difference). That's pretty challenging, as these are not small satellites either. For comparison the GPS network is 24 sats; given that satellites in low-earth orbit re-enter fairly regularly (residual atmospheric drag), we'd be talking about lofting something like the equivalent of the entire GPS network every month.
And that's assuming you could actually build a laser or interceptor that would work reliably - and that's by no means a given.
And that's assuming the opponent didn't start his attack by wiping out all the interceptor satellites that are in range of the launch field (they all have to be in orbit, and will thus be known and tracked). Remember, "buying the defences", especially when you have the element of surprise, is a technique that usually improves the chances of the offence greatly.
Look, no defense system is perfect, and noone ever claimed missile defense is a panacea. But it's better than sitting around, doing nothing to protect ourselves.
Didn't Reagan make exactly that claim? Anyway, your argument sets up a false dichotomy. Would the required 5% of GDP be better spent doing something else? Maybe the money should be used in anti-smuggling and border security ops? Or maybe, just maybe, we could stop trying to fsck over the rest of the world so maybe, just maybe, they'd be less inclined to lob ICBM's our way...
Just like the best lock will only slow down the best thief, not stop him, so too will the best defensive system only reduce the amount of damage done by the best offensive system. The goal is to increase our country's chance of survival
When the Soviets have enough nukes to personally provide a few kiltons to every man, woman and child in the U.S., it really doesn't matter if we could knock down 10, 50 or even 500 warheads. With 10,000 ICBM warheads (MIRV's, remember) and 30,000 tactical ones, the acceptable leakage rate has to be so rediculously small that it's surely wasted effort. I've seen professional assessments showing that 20-100 hits would be more than sufficient to destroy the U.S. as a national entity, killing 30 million people in the process.
You are thinking like a military guy, where even a defence that is 50% effective is worthwhile because it forces the enemy to double his effort. But when it comes to strategic nuclear war, the difference between 2 and 4 warheads/aimpoint is pretty immaterial.
Not decoy ICBM's. Balloon decoys. And hell yes. You can put ~100 of them on each booster because they are little more than balls of mylar. Look, it's sooo much easier to build a mylar baloon than an anti-missle interceptor that a few orders of magnitude in GDP just doesn't fscking matter. You may feel superior to the Russkies, but fact is that they have enough resources to build enough ICBM's that the U.S. simply COULD NOT defend against them. It's really that simple. And getting back to the original point, back in the 80's before the Soviets collapsed, they definitely had the resources to build an ICBM force that we could not defend against. No resonable person - even current SDI advocates - talks about defending against 1000+ incoming ICBMs, decoys or no decoys. All the current system is supposed to do is protect against North Korea and their 2 ICBM's. (In actuality the idea is to force the Chinese to spend real $$$ on more ICBMS so we can spend them into the ground the way we did the Soviets; those cheap bastards have been getting away with less than 100 ICBM's until now! Flawed logic for various reason we can go into later.)
And I haven't even started talking about counter-countermeasures other than decoys. You've got maneuvering warheads and buses, you've got chaff & jammers, you could set off a few nukes in space (completely wiping out any radar visibility for hours on end), you could have depressed-trajectory SLBM launches against the missle-defence sites, or you can have fast-boost ICBM's where the intercept time is very short.
Or you could just smuggle the damned things into downtown NY, LA and DC and be done with it, missile defence or no missle defence.
No, not really. The problem with intercepting an ICBM is above all one of decoys. The radar and IR sensors see an incomning cloud of 100 identical shiny, round objects. One of them contains a warhead. Which do you hit? Given that it's MUCH easier to build a decoy than an interceptor, that is a game that you can't win (assuming equal resources going in - which against the Russkies is a reasonable bet).
My bad..