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mmalluck

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Posts posted by mmalluck

  1. I want a nuclear-powered-atomic-watch! It might sound redundant, but it's not. We just use Cs for both the power source and the oscillator.

     

    This wont make space travel or anything any easier will it?

     

    They already use nuclear batteries in deep space satellites (Voyager) because they can't use solar panels because they're so far away.

     

    These batteries are just more efficient as compared to the old way they were manufactured.

     

    Unfortunately, as pointed out on slashdot, people are afraid of the word nuclear.

     

    Yeah, that is very true. I don't think we'll see this technology out on the consumer markets for several other reasons as well:

     

    There's laws on the books in the US that make the frivolous use of nuclear material illegal. Otherwise we'd have cool things like trasers here in the US.

     

    There's the question of what to do with a slightly radioactive used up batteries.

     

    There is also the fact that most high-technology devices are manufactured with a projected lifespan around 18 months (IE you don't need the battery in your cell phone or laptop to last decades if you're going to be buying a new one in a year or two).

  2. Well I'm no expert on lightning, but I can speculate from what I know from electrical engineering and physics.

     

    The goal of any lightning bolt is to get itself to ground taking the least resistive path possible. It wants a path that's short and conductive.

     

    If the ground is a good conductor, the bolt gets itself to ground quickly and their's less chance of a bystander getting hurt. It's reminds me of the guys who work on live electric lines.

    lineman.jpg

    They literally clip on to the high voltage line while it's active. Thier body is raised to the potential of the line, but they're unaffected because the wire is a more attractive conductor than they are themselves, even if they touch the same wire in two different places.

     

    Now soil is a funny thing, especially sand soil. The water in the soil will make it conductive, but as soon a lightning bolt strikes, all of the water becomes steam, and the soil dries. So the lightining bolt spreads to a more conductive part of the soil. Again the soil drys, so the bolt forks and moves again. That's how you get the spiderweb effect in the previous picture.

     

    With poorly conductive soil, there's a lot more of the lightning bolt searching for the best conductive path for the moment. There's a better chance the bolt will choose part of you for that path.

  3. That's a hard one to guess.

     

    I depends on the size of the bolt, the kind of bolt (positive or negative) and the enviroment.

     

    If the soil is a poor conductor, the bolt will spread through the ground and can electrify a much larger area, as compared a bolt produced over soil that conducts better.

     

    For instance here's a picture of the scortch marks left from a lightning strike on a flag pole that was left in a field.

     

    Golfcourse.jpg

     

    The scortch marks are about 25 feet across. If you were standing anywhere around there, you wouldn't be feeling too happy.

     

    Just because this thread made me think about this pic, I'll put it up as well. The person who took this picture survived. Click the picture for the orginal source page. They have some other very impressive electrical accidents (exploding utilities and the like).

    Lightling_Kane_Quinnella.JPG

     

    And here's the story that goes with it:

    The above photo is courtesy of Kane Quinnell - and it was almost his last. The above lightning stroke was almost certainly a "Bolt from the blue" - a relatively rare positive lightning bolt that originates from the top of a distant storm cloud rather than from the negatively charged cloud base. These massive bolts can travel horizontally for 10 miles or more from the center of the main storm. They can pack peak currents of up to 340,000 amperes, and they last for tens or hundreds of milliseconds. This is about ten times more current and ten times longer than regular (negative) lightning. These bolts are extremely hot, they do considerable damage to whatever the hit, and if you happen to be unlucky enough to get hit by one of these monsters, you DO NOT survive. Here's his description of what happened:

     

    "I happened to be out in the back yard, watching a storm on Friday night (14/01/05) that appeared to be a few km away, (I live in Old Toongabbie, and the storm appeared to be in Pendle Hill, or Greystanes, Australia). I set the camera's settings so that the shutter remained open for four seconds, placed it on the back bumper of my car, hoping to get a few shots of lightning in the clouds a few km's away. There was no rain at all, and stars could be seen over the north 1/3 of the sky, so I did not feel in danger in any way. Boy was I mistaken... DO NOT UNDERESTIMATE ELECTRICAL STORMS - YOU COULD GET YOURSELF KILLED!

     

    I clicked away a few times, and got nothing, and then clicked the button again, and within 0.5 seconds of me pressing the button, I had jumped at least 2 metres in the air, as I heard a tremendously loud crack of thunder, and see this amazingly bright beam of electricity right in front of me. I had then landed, grabbed the camera, and was inside the house within 2 seconds.

     

    I did not realize just how lucky I was until I uploaded the pic to my computer, and saw a leader stroke that must have originated no more than 2 metres from where I was standing next to my car, under my carport. Had the main charge taken the leader near me, rather than the one it did, I would be dead.

     

    When lightning strikes, it actually comes up from the ground first (called a leader stroke), this stroke makes the air within it conductive, and once it reaches the cloud, you have a complete circuit, and the bolt of lightning comes down from the cloud along the leader stroke. First leader to the cloud wins, luckily mine did not.

     

    I estimate that the main bolt was approx 1.5- 2 metres in diameter, and struck something in the yard behind the shed that is located at the back of the yard. That would have had an extremely large charge, and would have been extremely hot, hotter than the surface of the sun, at 5,500 degrees Celsius, it could have been around 30,000 degrees Celsius. Needless to say, I was buzzing for the rest of Friday night, due to the amount of adrenaline going through me cause of how close it had come."

     

    Kane Quinnell was one very lucky bloke!

  4. 1) they didn't actually get struck by the bolt, they were just close enough to get blasted by the hot compression wave the bolt produces.

     

    2) The duration of the bolt is so short, that the heat capacity of the body prevents them from becoming burning up.

     

    In all fairness my wire example didn't take the duration of the bolt into account. If the bolt was very short, the copper wire could survive. Peak power disapation may be 128,968 Kiliowatts, but if the bolt only last microseconds, considerably less heat will be transfered to the wire.

  5. Although, if that is right, it depends on the compound/element because air doesnt explode when lightning occurs.

     

    Ever hear thunder? That's the sound of the air violently expanding outwards due to the intense heat of the lightining bolt. The air explodes.

     

    As YT said, lightning will take the path of least resistance, but even a little resistance can cause the substance to vaporize when a lightning bolt hits it.

     

    To give you an idea:

    Strong lightning strikes can produce currents in excess of 200,000 Amps.

     

    Lets say the bolt chooses to go through some heavy copper wire on it's way to ground. We'll say it's 10 meters of 0 AWG wire.

     

    Using a handy-dandy wire gauge resistance chart we can see this wire has a resistance of 0.0032242 Ohms. That's a pretty small resistance.

     

    How much power will this resistor (the wire) have to dissapate when the lightining bolt pass through it?

     

    P=(I^2 * R)

     

    P=((200000 amps)^2 * 0.0032242 Ohms) = 128,968 Kilowatts

     

    The wire quickly becomes plasma.

  6. Now, I'll admit I don't know a great deal about speaker box design, but why would fill the box with helium as opposed to just building a smaller box?

     

    For a box with the least amount of stored energy, you'd have no box at all. You'd transfer the sound directly into a solid. Think transducer.

  7. Most religious scholars recognize that the Virgin Mary is simply a mistranslation.

     

    The ambiguous translation occurs in Isaiah 7:14, an Old Testament scripture which was translated from Hebrew into Greek around the 3rd Century B.C. There are two Hebrew words which are usually translated as 'virgin' (or 'parthenos' in the Greek) - 'Bethulah' and 'Almah'. Bethulah definitely indicates a virgin, whereas Almah most often means a young girl, depending on context. The word used in the original Isaiah is Almah, and refers in its context to a woman already pregnant, indicating that the 'young girl' meaning was the one intended. I should note that some scholars dispute this, stating that Almah also means virgin, but in a different sense (perhaps a spiritual metaphor?)

     

    The suggestion is not, therefore, that the New Testament itself, upon which the Catholic Church is based, contains any ambiguity - quijote quotes from Luke and Matthew, missing the point that these Gospels would have been specifically written in order to fulfil the Messianic prophecies made in Isaiah. The mistranslation in Isaiah prompted the authors of some of the Gospels to add further legitimacy to Jesus' status as the Messiah by stating that his mother was a virgin.

     

    This mistranslation in fact is disregarded, or not properly addressed, by the Catholic Church, which in its past has been extremely selective about which texts to include as part of its canon and which to consign to the wastebucket of religious history. Not all the Gospels maintain Mary's virginity, but only four are included in the New Testament Bible.

  8. Yes, probably sometime off in the future.

     

    How about any time soon?

     

    I wouldn't count on it. I won't happen until we exhast all the other fuel sources we have. The difference between hydrogen and coal or oil is that hydrogen is merely a form of energy storage, where as coal and oil are actual fuel sources.

     

    Huh? So how are they different?

     

    Well you can dig up coal or drill for oil, but you can't exactly go out and dig up some loose hydrogen.

     

    But we can make hydrogen!

     

    Ah, but to make the hydrogen you have to take a molecule and split the hydrogen off of it. This takes energy, more energy in fact than what you get back from burning the hydrogen.

     

    But don't you have to use energy to make coal and oil?

     

    No, no energy is actual used to make coal or oil. The only energy used is in finding it, getting it, and cleaning it. It's true that some energy is used in the processing of oil and coal, but nature has provided us with carbon-hydrogen bonds that contain the energy in the fuel. No energy has to be spent making the fuel. The chemical energy is already there.

     

    The difference between fossil fuels and hydrogen is the difference between finding a dollar by the side of the road and that of going out and working for a dollar. Which do you think people will go with?

     

    /end psycopathic thread mode/

     

    There, I've covered all the bases all by myself.

    Thread Over!

  9. But the energy you get back from combining the hydrogen back with oxygen will never be greater than the amount of energy the battery used to split the water.

     

    Lets do this as a formula:

     

    2(H20) + energy from battery => 2(H2) + (O2) + wasted heat

     

    The total energy on the right (both kinetic and potential) equals the total energy on the left.

     

    Why the Wasted heat? During electrolysis, the water will heat up. That's just a fact of life. There's no perfect way to split up oxygen and hydrogen molecules. Some of the energy always becomes heat. You can make the process rather efficient, but you'll never be 100% efficient.

     

    Lets give this equation some numbers for the energy totals.

     

    We'll say the 2(H20) has no particular energy content (water is rather inert) and we'll say the battery supplies one unit of energy.

     

    On the other side of the equation we'll say that the 2(H2) + (O2) has an energy content of .9 and .1 is wasted as heat.

     

    0 + 1 = .9 + .1

     

    Everything is nice and balanced as it should.

     

     

    Now lets turn our O2 and 2(H2) back into water to get our energy out.

     

    O2 + 2(H2) => 2(H2O) + energy

     

    How much energy go we get back? Lets go back to the energy units we used earlier.

     

    O2 and 2(H2) become .9 units of energy and 2(H2O) become 0, so

     

    .9 => 0 + energy

     

    Energy must be .9, but we put in 1 whole unit from our battery to split the water in the first place!

     

    Even if your battery was recharged by the engine, it would still run down over time due to inefficiency of splitting water molecules. Any kind of energy transfer will result in wasted energy and that's why there's no perpetual motion machines.

  10. In humans, maybe, but what about something like bees?

     

    The only thing the drone does is mate after which he dies.

     

    Even if all the drones are killed, the queen can simply make more drones. Incestious? Yes. Limiting the gene pool? Not really. It's part of the bee's survival strategy.

     

    In humans, if 3/4 of the male populations was lost, we would see some genetic limitation in the next generation, but this wouldn't last long. The female population still cares a vast array of genetic differences and in a few generations all would be well.

     

    Additional to that the loss of manpower and food gathering ability

    would also be catstrophic. not to mention the loss of ability to

    defend themselves.

     

    1) I think you underestimate the resourcefulness of women, but I agree that a loss of man power would see that population would further decrease. Things would tend to become more even.

     

    2) Defend from who? Other packs of waring females?

  11. Lets not forget about parallel processing.

     

    Computer are very good at processing code line by line in a linear fasion. We can use time slices (I.E. Computer, I want you to run this code for application A for X amount of time and then run the code for apllication B for Y amount of time) giving the appearance of parallel processing.

     

    You brain on the other hand can do dozen of things at a given time (taking care of vital functions, walk, talk, and chew gum at the same time) without having to switch between these functions.

     

    Hurray for specialized areas of the brain!

  12. This can be seen in nature many times over.

     

    Bees, for instance, take this to the extreme.

     

    All works are females. The only males are Drones and they die after they mate with the queen. The male only has one use and dies after he's no longer needed

     

    The Angler fish (the scarey fish in Finding Nemo with the light-lure on it's head) is also another interesting example. The female fish is what is commonly seen. The male is tiny in comparison. Once finding a mate, the male fish latches onto the female and lives off her in a parasitic manner. Over time the male fish becomes totally enveloped by the female leaving behind little more than a pair of testicles.

     

    I pulled these examples out of my head, but I also found a webpage that discusses these further.

     

    Females are nessary for a species to reproduce, males are only needed to the point of conception, after which they become expendable unless they preform some other useful task, like providing protection, gathering food, hunting, or caring for the young.

  13. I'm a computer engineer with a pension for RF work. One would guess I'd say Silicon, but I'de have to go with silver.

     

    The best conductivity of any metal, shallowes skin depth, heavy, cold, shiny, and won't leave your hands tasting like copper when handled.

  14. I'd have to say Silver is my favorite metal.

    It's nice, soft, shiny, and the king of conductivity. I just wish it didn't tarnish so quickly.

     

    I'd say helium is about as non-metal as you can get.

  15. Well I know the satellites responsible for GPS (and probably every other communication satellite) use the principles of special relativity to keep in contact.

     

    I know the GPS satellites are particularly sensitive. All a GPS satellites does is simply transmit a time code (they're just a big radio clocks in space). The receiver on the ground gets the time codes from various GPS satellites to calculate your position, but the receiver also has to take into account the velocity of the satellites and correct the time codes accordingly.

     

    Or in other words, special relativity is a well tested, well accepted, and well used theory.

  16. To maximize the electrolysis of water, you need lots of current. These means nice large electrodes with lots of surface area (looks like you're already going that way) and a hefty low voltage, high current supply. I know some guys who rewind microwave oven transformers for just such use. Link .

     

    Of course you'd have to rectify the output (so you get hydrogen at one lead and oxyegen at the other) and that may be troublesome due to the high current (100+ amp diodes are hard to come by).

  17. That's very skewed' date=' especially since light/perception (distance-perception) diminishes the further out something gets...likewise, the further out the lightbeaem goes, it's actually traveling in a triangular pattern in terms of distance, because up close it's large and the further out it goes it gets smaller (like a cone).

    [/quote']

     

    Huh? Are you saying you're using your eyes to measure the speed of light? That's like using your arm to judge how heavy a mountain is. In this example you'd have to have some equipment to measure the speed of light. That's a given.

     

    The shape of the light beam has very little to do with the speed it travels. If you'd like we could use a series of single photons to make our beams (IE the thinest beam possible).

     

    Now if you're talking about "light cones" you should go back to my Special Relativity and Light Cones link and do some reading. It comes from the same page as the mirror clock thingie.

  18. What? Why would an outside observer think the wall is moving away from the light source?

     

    The distance the light has to travel becomes longer according to the stationary observer. Light may be fast, but it's still bound by a set speed.

     

    What I'm talking about is illistrated by the time dialation link I included earlier.

     

    And for those too lazy to go to the link:

     

    You have two guys with simple clocks. They bounce a beam of light off a mirror and see how long it takes for it to bounce back. Borrowing images from the link. It would look something like this:

    time.gif

     

    Now if the blue guy goes running off with his clock, according to the stationary red-guy observer, the beam of light in his clock has to travel along a longer path from the mirror and back. It travels along a diagnol and would look like this:

    timev.gif

     

    If the red-guy measures the speed of the light in the other's clock, he finds it's traveling at a constant 2.998*10^6 m/s, just like his.

     

    From the blue-guys moving frame of reference, the light is going straight back and forth between him and the mirror at the same speed of light and there we have paradox, unless we take time dialation into effect.

     

    Accoring to the Red-guy, Blue's clock is running slow. Accoring to the Blue-guy, Red's clock is also running slow.

     

    Me and that webpage do a kinda of crappy job explain this. There's other's out there that are better.

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