Danijel Gorupec

Nice one... It just occurred to me that we do not see any "show off" from them. We people enjoy erecting large structures just to show how great our nations are.... Compared to us, these advanced civilizations must be very non-existent or very humble. They are not even showing some star-size art. Must be they also have small budgets for culture. .... Btw, I am just thinking about Dyson spheres... I am imagining a whaling ship captain in 1650 who is dreaming about a sailboat capable of transporting 100000 tons of whale oil. He concludes that one day people will have the technology to make such large sailboats. But today we do not use sailboats to transport oil, instead we are using diesel-powered boats. Building such a large oil-carrier sailboat would look a bit silly... That is why I don't expect much Dyson spheres around. It might look like a good and advanced idea to us now, but once when we will have the technology to actually build one... well, it will look just too cumbersome and silly. Our neighbors might ridicule us.

hmm... Is anyone saying that the nuclear energy is not safe already? On what ground? Many kids are truly terrified of the closet monsters, but those kids are never in a real danger. When most people say "how dangerous reactors are", they actually mean "how scary reactors are". Because this is an engineering forum, I expect clear wording here. What is it about nuclear reactors needs an urgent improvement - their safety record or public opinion about them? Yes, I think that we should improve the nuclear reactor safety records a lot! As well as for cars, airplanes, drugs, food and anything else... What causes me a great pain is when I hear an engineer saying "this is bad, throw it away" instead of "this is bad, it should be improved". What kind of an engineer would not like to try to improve something? Nuclear energy is a recent discovery and a new technology - we do not throw away discoveries that easy! New technologies are only found once in a hundred years. I don't think that public opinion about nuclear energy is healthy at the moment. Even if we declare present technology as too dangerous, the "destroy all and stop everything" public stance seems unhealthy. At least some positive attitude to future technology research should be present. We engineers failed to provoke at least that. Anyway, my answer to the OP is: you posted it in the wrong forum. Engineers cannot make that technology appear safe to the public any more - it is too late. Rebranding is needed - please contact the marketing department. Acme, this was hilarious! Did you do it on purpose? It is not that I agree with your quoting, but I still find it funny ... I almost missed it.

To answer you question first: there is no fool-proof way to make the distinction. (but you don't even need know the way to make the fool-proof distinction - because all you have to do is to make sure that nobody else can prove that you didn't act in a good faith) You cannot avoid being sued! This is one of the most common things in a democracy. However you can ask the court to compensate for your time/pain if it is found that you are not guilty.

But even if you accidentally download some unwanted material, you are still a good citizen. You are a victim... Don't you feel so? Anyone accusing you will have the burden of proof that you are not a victim, that is how I see it.

I don't understand some of you guys here... Why are you talking about 10km deep borehole as if it is a piece of cake? We are drilling into the Earth crust vigorously for decades and such depth still is an expensive adventure... and no one can say that our drilling technology is immature. It seems that it is genuinely hard to drill deep holes. As a result, with today technology, we are either limited to low-temperature-low-efficiency plants, or to high-temperature-big-business plants. If this is true, we cannot expect that geothermal electrical plants will become as wide-spread as solar or wind. Big business might also prefer other reasons than ecology (and I am not suggesting that big-business is evil). I suppose that geothermal heating of homes has more potential to become a wide-spread technology than electrical generation. Drilling low-depth (few km) holes might become a rudimentary job, maybe... (On the other hand, you can heat your home from coal/gas/nuclear plant for even less money. Not something you can do with wind or PV plants, btw.) But the one thing I read on Wikipedia is the worst of all -> the heat flows to the Earth's surface at 30TW rate! This is much less than I expected (I even doubt it incorrect?). We will need that much in only a few years. In a hundred years 30TW might represent only 10% of our needs. Not much future for the geothermal energy, I would say.... Makes me sad.

Mostly @Enthalpy, Of course, as the technology advances, so should black boxes. If better pingers are available (as you suggested), sure. If better batteries are available from the same price range, yes absolutely... But I understood the original thread question as "should we make considerably smarter/better black boxes that will provide additional features (like long-range guide)?". If this indeed is the question, then I will be very cautious to answer 'yes'. This is because I believe that money can be better spent if we invest it into better plane-tracking systems. In the case of MH370, better tracking systems would do better job than better black boxes. For me, the most odd thing about MH370 is not our inability to find the wreckage, but the fact that there is possibility that the plane was flying for hours without anyone being aware of it. BTW, I am just curious... would you prefer black boxes capable to emit 'louder' signal, or black boxes capable to emit signal for longer time? I suppose that if our goal is to find the wreckage faster, then the better choice is the loud signal. If our goal is to recover the black box itself (for aftermath analysis) then the better choice is the durable signal. Some cold logic at the end... Finding the wreckage quickly only has 'real' meaning if it can be done in few hours, and this is only possible if your plane-tracking systems already told you where to go. After this time, the only thing that one should hope to find 'alive' at the wreckage site is the black box. That is why I think that the durability is more important feature for a black box than its 'loudness'.

Not trying to be a party pooper, but maybe we are mixing apples and oranges... Planes may need better tracking devices to help us find the wreckage site faster. But this tracking is not the job of the Black Box. The black box is used to provide aftermath insight - to help us build better equipment and better procedures in order to prevent future failures. The black box has a transmitter device so that the box itself can be found withing the scope of the wreckage site. Its transmitter is not intended as a long-range guide to the wreckage site (they are trying to locate the wreckage site by searching for the black box signal only because they are desperate enough - this is how I see it).

I am not that sure the low-frequency sound would work very well for black boxes. I suppose that you would need a rather large device to emit a loud low-frequency sound. I also suppose that lot of energy will be needed. For the second part I completely agree... It is funny that the military missed this plane. Very embarrassing.

When you switch off the magnetic field (by switching off the field current), a DC motor will perform the runaway. A non-loaded DC motor (and similar types) will accelerate until its back-EMF (almost) equals to the supplied armature voltage. The back-EMF generated by a motor depends on its rotation speed and the strength of the magnetic field inside motor. If you decrease the field strength without decreasing the supplied armature voltage, the non-loaded motor will have to accelerate further to generate enough back-EMF. Note however that the runaway will only happen if the motor is under light load (or non-loaded) because as magnetic field strength decreases, also the motor torque decreases.

Partially agree... we were a bit luckier than some others, but there was still more than enough blood. For the original question "why do so many Americans hate communism?"... I am not sure if the question is related to hate that comes from 'fear of unknown' (fear for own sake), or is it related to hate/disgust because of what communism did to others. I think that both causes of hate are present in American society, possibly the former being much stronger cause in the beginning. If an average American could better understand how economy and democracy works (from macroscopic perspective), instead of hate they would feel pity. They would realize that communism has no chance in relatively sound society of America.... or am I too naive?

I believe that AI will be sentient one day (today we are making 'toys' that fake emotions and personality, but I believe that one day we will learn how to make truly sentient software). Of course, It seems that at the moment nobody can say what exactly makes somebody/something sentient. Therefore I suppose that in future we will have long discussions about whether our machines are sentient or not. Somehow I doubt that a sentient being can exist without emotions (of some kind). It is because I believe that emotions are strongly connected to motivation, and I doubt that an unmotivated sentient being can exist. Even if it can, we people would have hard time recognizing it. Reasons for my believe in AI is because I don't think that there is anything that 'exist outside' our brain tissue. But I must admit that the question of consciousness is very puzzling. Sometimes I even wonder if there is a 'law' that tells that an intelligent being can never really understand its own complexity level.

I think this is possible. But even in this case, I think, people will have dual citizenship - of a terrestrial country and of a cyber nation. This is because people will live in both worlds (physical and cyber). [ I also believe that conscious computer software could soon be realized (in less than 50 years), and 1-2 decades after that we will probably have to recognize their civil rights. Those entities will probably create some sort of cyber-nation(s)... I actually believe such development is almost a certainty and I would bet that in year 2100 there will be more than 500 billion conscious minds on this planet (about 10 billion of them organic). ]

Interesting. I am just thinking out loud... maybe "on the bus/train" actually comes from "on the bus/train line". I also noticed following in the above discussion: - "why did you use 'at'..." (it sounds ok to me) - "why did you use the 'at'..." (sounds weird to me) - "why did you use the word 'at'..." (again sounds ok to me) But I actually can't understand why the word 'the' in the second example doesn't fit. Or does it?

Phi for All (or anyone)... can you elaborate why did you use "at" in the third line (why not "on" or "to")? Thanks.

Otto-cycle engines need spark plug (or any other 'external' mean to light the fuel mixture in the right moment) by definition. The spark plug is one of things that makes them 'otto cycle'. You could build a diesel-cycle engine that uses petrol, but this would be difficult because very high pressures will be needed. You could make some other type of engine that uses petrol, while does not have a spark plug (gas turbine perhaps?)... What I want to say is that by saying "petrol engine" you tell nothing about engine construction, only about fuel it uses. If you want to refer to construction details, you should use terms like otto-cycle engine, diesel-cycle engine, gas turbine...

If the reason for not having the Moon is because there was no collision with Theia, the difference could be dramatic (supposing that the impact hypothesis is correct). Earth axis tilt could be smaller, core composition could be different (including water percentage)... maybe even life would be completely different (if we suppose that there was some life before the impact)... but this is pure SF. The famous JFK speech would be "We choose to go to the Mars..."

What Externet described may be considered incorrect in all but most general explanations. As you are asking your question for bipolar-junction transistors (BJT), you probably know that the base current controls the collector current (precisely as you asked) and not the collector-emiter resistance (as Externet explained). You asked your question in the physics forum, so I suppose you want some in-depth picture about what happens inside BJT (or?). As this is somewhat complex mater, it could be better if you systematically read about it somewhere else (internet or books) and then come here and discuss more specific questions... Or tell us what you know already so that people here can start answering from somewhere.

I like the idea. I think it can be useful to clean very small debris (maybe 1mm, or smaller) from lower orbits. I hope that even if such very-low-density material breaks into pieces, those pieces would de-orbit much faster than more dense particles because of relatively high drag (in LEO there is some atmosphere). I don't know if you already read about the similar (less ambitious) way they used to collect dust from a comet: startdust. They used aerogel.

So, when we see lighting it means that we just saw electric energy being "wasted" (turned into heat, sound and light that cannot be easily collected). So, we should avoid lighting to occur? Instead, would it be better if we build an array of air ships (baloon) interconnect them with thin web of conductive (carbon) wires to collect charge, and anchor the whole structure the ground with some additional conducting wire. Would the current flow through the anchoring wire in some weather conditions?

Let me try.... If we people see that, for some reason, the whole population of macaques (monkeys) is endangered by some disease, we would not hesitate to kill a few in order to find a cure. Science-Fiction: If a very advanced (and lonely) civilization finds that there are several millions of child-level civilizations all over the galaxy, 99% of them destined to die young without ever reaching maturity, the advanced civilization might decide to conduct some, possibly fatal experiments on few "civilization-specimens" in oder to discover a "cure" to preserve others. We people do similar things sometimes when we are trying to preserve endangered species.

I always considered intelligence as a tool/resource that we use to achieve our goal - happines. I am surpirsed so many of you preffer intelligence (a tool)... Are you then also the same type of people that enjoy working on a problem better than having the problem solved?

Certainly! I make a strong distinction between terms overpopulated and overpopulated by: A) The environment is overpopulated by humans. B) Humans are overpopulated. The A) is concerned with environment future, while B) is concerned with humans future... Having this in mind, if I am allowed, I will now answer your OP question: If you asked A) the answer is trivial and is: Yes If you asked B) the answer is less trivial, but I think it is: No

I think, the science of Biology will have to clarify the term 'overpopulated'... Definitions like "pupulation size that cannot be supported by the environment" are unclear when it comes to tech-capable beings like humans. From such definition it is not clear whether the environment is alowed to change substantially or not... Humans are, however, capable to change (to engineer) the environment substantially into a very different form that is capable to support them. Because of this, there is now a communication problem between you and me. (Despite the fact the we both agree that the pressure from humans toward wilderness is much too high for wilderness to sustain.) This also makes the poll question unanswerable to me.

As other said, the practical joke (studiot) and instrumentation/settings error (swansont) seem like the most likely answer. Only if the hot plate is heated by magnetic field (eddy currents) or some sort of microwaves, and there are substantional leakages, I would dare to accept such odd readings.

No no. Wolves, in your case, are becoming overpopulated as soon as there is nothing they can do to prevent their future die off.... Humans are not, I think, in this position yet. We are capable to sustain our current numbers, but the price is to destroy the wild life... This seems like a high price to pay, but as far as I know humans, we are not going to think twice. Huh... defining the term 'overpopulated' in terms related to 'pressure to environment' is wrong. There was a time in history of life when oxygen-generating bacteria killed many other creatures providing enormous pressure to the environment. But I would not dare to say that these bacteria suffered from overpopulation - they just changed the environment for good. This is what humans are doing now.