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When light enters a different medium changes its propagation speed, right ? ...does it decelerates or accelerates at that transition ? When light at c hits a mirror and bounces back at -c, there is an instant when its speed is zero. Is it?

Impressive work shown live on NASA TV; and I wonder... All those items, assemblies, tools they are handling, replacing, touching... at what temperature are they ??

Solid ? ... An iron bar. Red hot is still solid.

Different approach residing in my 'favorites' for years : http://www.eskimo.com/~billb/miscon/whatis.html Miguel

Just wanted to share what I just saw; when I got the camera the bird was gone. A hummingbird feeding from spiders that hide under a handrail at my home exterior. Thought they were strictly vegetarians. At least this one is not.

Partially agree with the drag, but the question was about counteracting the tilt Partially, because the huge, huge ballast in a non-catamaran sailboat keel could be then highly reduced, which would decrease draft and consequently drag. Martin: http://www.cs.unc.edu/%7Ekeller/catamaran.jpg http://farm1.static.flickr.com/101/266091389_a41ac7525c.jpg

A sailboat tilts considerably with strong wind. Could a sailboat fitted with an inverted T keel, the horizontal 'wings' capable of independently adjusting pitch, force the hull to stay level ?

Intersting... http://www.scribd.com/doc/14599592/A-Beleza-Na-Matematica

Hi. Why a diamond needle wears out by playing vinyl records ? What is there in vinyl harder than diamond in order to erode it ?

If a small, -say 1cc- human brain portion is safely, properly replaced/swapped with same exact lobe/area from another human; would it carry memories/functions/knowledge with it ? Has it been done ? How good/accurate/reliable is the current surgical technology for something like that ?

Hi. A liquid crystal display has indium? transparent traces that make the electric contact to the circuitry and enter the glass sandwich to turn on the segments, and a couple of the traces seem interrupted. Is there some simple easy-to-find liquid that I can apply with a (nail painting) brush to those traces to restore electrical path, and stay conductive after drying? Does not need to be transparent, the available silver inks to do the work are more expensive than the item to be repaired, and I would use a 0.01% of the bottle. Not worth it. Thanks, Miguel.

Hi. Thanks; it is getting really hard to put this in the right wording. It is not about avoiding a gearhead. Such motor would be driving a gearcase. A speed controller would be used too. It is about decreasing the components ratings and stresses. A power source, a controller, the wiring and the motor itself are subject to greater stresses when starting to spin a motor under load because the slow commutation speeds and very large currents. For a given torque need starting under load at -say 0.5 rev/sec- demands a lot of current. That same given torque need can be achieved with smaller forces (weaker magnetic fields) applied more distant from the shaft It is not about increasing energy output. Comparatively, it takes less force to manually spin a wheel by turning it as far as possible from the shaft than turning it near the shaft to produce the same torque. It is about using less force x larger distance from the shaft to achieve the same torque and at the same time getting high tangential speed. Would that demand less current ? Trying again : As a smaller force far from the shaft (large disc shaped motor) can achieve the same torque than a much larger force near the shaft (conventional shape motor); a weaker magnetic force (smaller windings, current and ampere turns) far from the shaft can achieve the same torque than a much larger force near the shaft (large windings, current and ampere turns)

How could a permanent magnet electric motor be built/designed for slower rpm turning shaft but with 'normally' high commutation speed (passing of magnets in front of coils) ? Would a 60cm - 100cm diameter motor just ~5 cm thick -disc shaped motor, with a large number of magnets placed at the peripheria and a corresponding large number of coil poles do it ? Being the magnetic propulsion forces at a 'large' distance from the shaft with a large tangential speed use less force to produce same high shaft torque ? It is hard to express in writing, I hope the above is understandable...

I would venture to say that if the algae and organisms have cells, they will be ruptured by the pass of electric current and die, in seconds. And the 220VAC live or phase wire, if its other return neutral is grounded, you do not need to submerge both in the pool centre. The phase wire will create the current towards the body of the pool. The circuit breaker does not need to trip, the current can be easily limited with a light bulb in series: 220VAC--------breaker or fuse--------bulb-----------water---------pool surfaces(Ground) Obviously any grounded metal attached to the pool surfaces will concentrate the current towards its sorroundings. I would try. Nothing to lose. No risks of anything if done with common sense and safety precaution. You don't throw a live wire to the pool. You dip them first and then turn on. The highest the wattage of the 220V light bulb, the highest the current forced trough the water. And ions from chemicals in the water, also will increase the current. If the 220VAC is two phases, floating from ground, you can dip both in the pool ends as you say, with the bulb in series. It won't trip any breaker.

The proof a camera does not capture souls, is to take more photographs of the same 'now souless' subject from the first picture...

Hi Is there combination of foods that can cause health/digestive problems, but consumed individually are perfectly 'normal' ? (It is not about flavor - fried eggs and cocoa type of mixes)

And a true geostationary satellite, would not really be in orbit ?

Imagine an extremely buoyant balloon rises vertically to -say stratosphere- , and stays up there; Could it be called being in a geostationary orbit ? -Ignore winds-

Thanks, fellows. Seems there is some interesting truth in the technique. Would the use of borax instead of an antibiotic produce similar results ? What other compounds you suggest that embedded in paint or epoxy will prevent the growth/attachment of marine life to a hull; without contaminating the sea - I mean, would be effective when the organism erodes the paint and reaches the toxin; but the toxin would not be washed itself by the sea. Miguel

..."to sweat out the fever"... What is that ?? ..."42 degrees is enough to make you sweat"... I thought sweat can happen at any body temperature. Can you explain ?

Are all warm blooded animals regulated at 37 C ? Why 37 ? Why fever does not go beyond 42 C ? Is it at 42 C the sickening microorganisms are 'killed' by the body thermal rise defense ? In occasions with near 42 C fever, I have had allucinations, and after that, a relief/cured sensation. What goes on ? Did the fever actually killed the 'illness' ?

Thanks. The explanation I received is that barnacles and algae footings/rootings do erode the epoxy surface to secure attachment, and is when they become in contact with the until-then-preserved, embedded, still active antibiotic. And done that way because the cost of currently available commercial anti-fouling coatings is too high for the service time they provide. The light, poor attachment of algae that occurs even with this treatment just washes away by itself with boat motion.

Someone I know mixes eritromycin with clear epoxy and paints the hull of his boat, a kilo in 10 litres. Says lasts over 10 years, with nothing attaching/growing on it. Any compound that would have the same effect ? At my location, antibiotics are not sold freely. Don't know if 'equivalent' can be twisted towards some kind of poison that could be a marine life permanent danger. The confinement status of a non decaying killer/contaminant product in epoxy can be arguable, I understand.

You should not find difficulties in finding heat calculations if stay with kilograms, litres, joules units... and do not toss farenheit, square feet, inches, btu units ... into the mix.

In case is of help to anyone; buying an 'unpleasant' brand of cigarrettes does diminish the smoking; if does not give you also a nasty throat infection* that forces to not smoke for at least several days. That can be used as an opportunity to stretch the days and hold on to a non-smoking future, or change then to yet another brand. I have stopped two or three times for a year or so; and now am back on a much less intensity; but just because I am bored at work breaks, and do not now what to replace the habit with. Smoking gives me nothing, no high, no relax, no nothing, no shit. Just a sensation while smoking that cannot feel later nor lasts. If someone comes up with a similar harmless thing to aspire it would be good to switch to. *Seen it happening several times. A change in brand nests some different kind of resident microbes on the throat that we have built no defenses against ¿? Miguel