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      CommentAuthorAngus
    • CommentTimeJan 21st 2015 edited
     
    Whoops. Old age strikes again.
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      CommentAuthorTrim
    • CommentTimeJan 21st 2015
     
    Maybe you can have a bone marrow transplant with new fresh bone marrow made by some of your own blood cells?

    Should rejuvenate yourself quite nicely, a bit painful though.
    • CommentAuthorbr
    • CommentTimeJan 21st 2015
     
    Posted By: AsterixHere it comes--a Kickstarter
    I haven't had any more contact with this guy, but he posted a comment where he claims:
    'You can’t measure the magnetic field from an electron or proton beam. Why because there isn’t one from the beam.'
    which is obviously wrong (though I couldn't actually find a reference where it was done...).

    As his funding is just over 1% with 33 days to go, there's not much chance of his project going ahead this time round. Doesn't mean he won't try again, of course.
  1.  
    Hmm. I found this strange little paper:
    http://educate-yourself.org/cn/ElectronBeamMagneticField.pdf
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      CommentAuthorAngus
    • CommentTimeJan 21st 2015
     
    Bizarre. You might think that some such effect would have been noticed in electrostatic deflection CRTs.
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      CommentAuthorTrim
    • CommentTimeJan 21st 2015
     
    Po

    Amazing what people with open minds can come up with.

    New analysis shows a way to self-propel subatomic particles.

    http://phys.org/news/2015-01-analysis-self-propel-subatomic-particles.html
    • CommentAuthorAsterix
    • CommentTimeJan 21st 2015
     
    CreatorAnd every Nobel Laureate of the early 20th century knew that heavier then air flying machines were impossible too.


    I take that as a red flag meaning "I'm spewing garbage, but trust me--I have vision, unlike all of those benighted Nobel laureates.

    In fact, heavier-than-air flight was pretty much impossible (other than balloons and glider-type stuff--until development of a power source wit sufficient power density (ICE) became available. I'm not aware of any reciprocating steam-engine powered plane.
  2.  
    And of course there are the myriad examples from nature: birds and insects, all heavier-than-air flying machines. The Wright brothers made sustained soaring flights on the ridges at Kill Devil Hill, developing control systems and piloting skills, long before they took their best glider design and hung an engine and propellers on it.

    I'm surprised the writer didn't mention that bumblebees cannot possibly fly, either.
    • CommentAuthortinker
    • CommentTimeJan 21st 2015
     
    There have been several steam-powered aeroplanes. All of them small, some worked ok, but they were pretty much made as curiosities.
    • CommentAuthorAsterix
    • CommentTimeJan 21st 2015
     
    Posted By: tinkerThere have been several steam-powered aeroplanes. All of them small, some worked ok, but they were pretty much made as curiosities.


    I could possibly see a steam turbine or jet setup, but reciprocating-piston flying machines?
    • CommentAuthortinker
    • CommentTimeJan 21st 2015
     
    There is YT video - but blocked for copyright reasons so I have been unable to see it.


    A Travel Air 2000 biplane made the world's first piloted flight under steam power over Oakland, California, on 12 April 1933.
    The strangest feature of the flight was its relative silence; spectators on the ground could hear the pilot when he called to them from mid-air.
    The aircraft, piloted by William Besler, had been fitted with a two-cylinder, 150 hp reciprocating engine.
    An important contribution to its design was made by Nathan C. Price, a former Doble Steam Motors engineer.
    Price was working on high pressure compact engines for rail and road transport; the purpose of the flight was to obtain publicity
    for this work. Following its unexpectedly favourable reception Price went to Boeing and worked on various aviation projects, but Boeing dropped the idea of a steam aeroengine in 1936. Price later worked for Lockheed where his experience with developing compact burners for steam boilers helped to design Lockheed's first jet engine.
    The advantages of the "Besler System" that were claimed at the time included the elimination of audible noise and destructive vibration greater efficiency at low engine speeds and also at high altitudes where lower air temperatures assisted condensation; reduced likelihood of engine failure; reduced maintenance costs; reduced fuel costs, since fuel oil was used in place of petrol; reduced fire hazard since the fuel was less volatile and operating temperatures were lower; and a lack of need for radio shielding.
    For capacities in excess of 1000 horse power a turbine captures the energy released by the expansion of steam more efficiently than a piston. Thus, the steam reciprocating engine turned out to be unsuitable for scaling up to the needs of large aircraft.
    • CommentAuthorAsterix
    • CommentTimeJan 21st 2015
     
    Didn't know about that. Was the aforementioned engine and boiler the usual cast-iron and steel-plate construction or did it make use of materials and methods not available in 1900?
    • CommentAuthortinker
    • CommentTimeJan 21st 2015 edited
     
    Abner Doble (who built some fine steam cars in California in the 20's and 30's) designed a high-pressure cyclone steam boiler in which water was pumped though a coil of steel pipe which was exposed to a fan-boosted kerosene burner. Called a 'flash boiler'. Doble engines were twin-cylinder double acting piston engines with roller-bearing crankshafts which 'flat out' could produce anything up to 250 hp. They probably had the best power-to-weight ratio of any steam engine ever built up to that time.

    No revolutionary materials AFAIK, but machining to tight tolerances and an emphasis on lightness and high torque at relatively low rpm.

    Try this...

    http://www.douglas-self.com/MUSEUM/TRANSPORT/steamplane/steamplane.htm
    • CommentAuthorAsterix
    • CommentTimeJan 21st 2015
     
    Very interesting, thanks!

    What SF story was it that talked about a "steam gull"?
  3.  
    Posted By: alsetalokinHmm. I found this strange little paper:
    http://educate-yourself.org/cn/ElectronBeamMagneticField.pdf
    Curious indeed and I don't believe it.

    Take a straight electron beam of circular cross-section 1mm2 (so r = 0.564 mm). Take the beam current to be 1.6 uA. Both these numbers are reasonable and fairly typical values around and about, I reckon. Then there are 1013 electrons passing per second (independent of the beam cross-section). Then the magnetic field due to this beam current is 10-10 T at a radial distance of 3.2 mm - about 6 beam radii distant, so hardly "near field" I believe.

    Now, how to calculate the putative contribution from the magnetic moments of these electrons? ....
    • CommentAuthortinker
    • CommentTimeJan 21st 2015
     
    There you go, easy peasy. (says WikiP)

    Reduction of the Dirac equation for an electron in a magnetic field to its non-relativistic limit yields the Schrödinger equation with a correction term which takes account of the interaction of the electron's intrinsic magnetic moment with the magnetic field giving the correct energy.

    For the electron spin, the most accurate value for the spin g-factor has been experimentally determined to have the value

    2.00231930419922 ± (1.5 × 10−12).[2]
    Note that it is only two thousandths larger than the value from Dirac equation. The small correction is known as the anomalous magnetic dipole moment of the electron; it arises from the electron's interaction with virtual photons in quantum electrodynamics. In fact, one famous triumph of the Quantum Electrodynamics theory is the accurate prediction of the electron g-factor. The most accurate value for the electron magnetic moment is

    (−928.476377±0.000023)×10−26 J⋅T−1.[3]
  4.  
    Oh I know all that. But tell me the magnetic field due to the magnetic dipole moment of the configuration I described. :)
  5.  
    Posted By: Andrew PalfreymanTake a straight electron beam of circular cross-section 1mm2(so r = 0.564 mm). Take the beam current to be 1.6 uA. Both these numbers are reasonable and fairly typical values around and about, I reckon. Then there are 1013electrons passing per second (independent of the beam cross-section). Then the magnetic field due to this beam current is10-10Tat a radial distance of 3.2 mm - about 6 beam radii distant, so hardly "near field" I believe.
    The magnetic field per electron due to its magnetic dipole moment, at the same distance of 3.2 mm, is 6*10-23 T. 1013 electrons flow per second. What's the total field? Buggered if I know.

    A moronic multiplication of 6*10-23 T by 1013 yields 6*10-10 T, but that's purely arbitrary, based as it is on the # electrons per second. But you can see that it's close to the other value at least.
    • CommentAuthorbr
    • CommentTimeJan 22nd 2015
     
    Posted By: Andrew PalfreymanWhat's the total field? Buggered if I know.
    What you need is the number of electrons per metre of beam, and then do a line integral to sum all the contributions. However, to get the number/m, you need the velocity, which is unknown. Also, the field from a dipole reduces as 1/r^3, so only the section closest to the nearest-point will contribute. If one takes a 10 cm length of beam as contributing substantially to the sum, then a first approximation is to divide the answer you got by (10.v).

    Take v=1 m/s, then your moronic multiplication will give a field of 6.10^-11 T.
    If v= 100 m/s, you get 6.10^-13 T.
    etc.

    Note that this does depend on which way the electrons are pointing - 'longitudinal' measurements are twice that of 'equatorial' measurements.

    What I don't get is why he expected the electrons to all be pointing in the same direction. For that, I think you need a Stern-Gehrlach setup. After that, then one may expect to look for these things. I don't think field emission produces same-spin electrons.

    At least that weird paper claimed to have measured the magnetic field of a free space electron beam, but after that it doesn't sound right.
    • CommentAuthorLakes
    • CommentTimeJan 22nd 2015
     
    Posted By: Asterix
    Posted By: tinkerThere have been several steam-powered aeroplanes. All of them small, some worked ok, but they were pretty much made as curiosities.


    I could possibly see a steam turbine or jet setup, but reciprocating-piston flying machines?
    This made me think about steam trains and the smoke stack, why was the engine at the front and not at at the back, where all the smoke will be blown away from the passengers?
    Is it somehow more efficient to pull the carriages?, something to do with braking?