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If a heat source cannot be concentrated to a hotter temperature spot, S M M M M M M Radiation from the sun S above heats and illuminates this target ---> + to -say 50C- with the intensity of one sun. The radiation from the sun S hits mirrors "M" at left aligned to all reflect onto target + to a total of 7 suns intensity. If the mirrors were covered with an infrared pass filter that blocks visible light, the target + will not be hotter than 50C ? Again; If a heat source cannot be concentrated to a hotter temperature spot, Does it mean the heat at the top of this tower comes only from the concentrated reflection of visible light and the heat part of the sun radiation is not a factor ? ----> http://www.nickelinstitute.org/multimedia/magazine/2008/December_2008/Solar/solar1-650.jpg Miguel

OK. Let's say that infrared lenses do exist. Where in the spectrum heat falls, am unsure if those lenses be functional: http://www.3dlens.com/infraredfresnellens.htm http://www.thorlabs.com/navigation.cfm?Guide_ID=132&gclid=CMbxi9fwr5sCFSIuagodb1nWCg A pot boiling water on your stove top, 20cm size, 100 C. If an infrared lens is placed in front of the pot, its 'projected' infrared focused point to a 1 cm spot would never be over 100 C, as I understand from what has been explained. Miguel

Thanks. Yes, it is to happen at atmospheric pressure, for distillation; and as suggested, 'flash evaporation' makes better sense than 'flash distillation' even when that is usually named when performed at partial vacuum. Miguel Merged post follows: Consecutive posts merged The instantaneous steaming is because pouring the water slowly seems the preferred method for a small size vessel that is permanently at 600 C + and evaporation is wanted for distillation. The agitation from boiling causes an undesirable spill effect in this small vessel. The excess high-heat at the vessel is a waste by-product of a combustion process, trying to be used in the needed distillation instead of dedicating an additional heat source. The vessel is to be periodically scraped to remove deposits left from the evaporation. Miguel

L1 = L0(1 + αL(T2 − T1)) The formula to find how long will be a stainless steel rod , alpha=17.3 from initial length 700mm after delta t = 600 C Yields a senseless number. Where am I goofing?

Hello. Slowly pouring water onto a very, very hot vessel so there is instant steam production; how is that method called ? -It is not 'flash' distillation- Miguel

Venturing to speculate, a compressor needs valves to isolate the compressed gas from the rarified gas when exposed to a pulsating wavefront. A piezoelectric transducer has a deflection measured in microns; and cannot see how such microvalve could be built to react at over 20KHz with such a tiny gap. The amplitude of wavefronts is also equally small. Lower audio frequencies -say 60Hz- do create more convenient compression amplitudes and standing waves in a calibrated length acoustical port duct. Tapping the compressor outlet at that location on the duct, could raise pressure, but not much flow unless an inlet is provided at the standing wave antinode. Search for acoustical wave compressor, I read something about it a long ago. Miguel Edited: added----> Fig 10 at patent 5167124 is supposed to be in ultrasonics. I did not guess too bad!

One soaked black towel, made of 100% cotton in same test conditions as another black 'towel' made of 100% nylon; under the sun... Which one would evaporate/dry more rapidly ? -Or is there any other better material choice with the same texture- Miguel

More Amperes at less Volts are achieved with less turns of thicker wire. The rpm and magnetic field strenght are both directly proportional to the multiplication of Amperes and Volts; that is, Watts. More speed or more magnetic field will raise both figures = more Watts Miguel

Let me try another wording/example. If a person is at a focus of an elliptical mirror; would the body heat reach the other focus and warm up a little object placed there to same or more than 37 C ? As a lens and light. The light gets brighter at the focal point of a lens because all rays merge there. If radiated heat behaves as radiated light but in another wavelenght, how to harness/route/handle that heat radiation into a 'spot' which will get hotter than the heat source? Miguel

As light can be focused to a small area with the use of a lens, how could heat -say from a household radiator- be concentrated into a smaller area ? As to focusing invisible heat from a large source to raise temperature of a smaller body- Miguel

Has anyone related affective times in life with more vivid dreaming, like pleasant dreaming in color and with details remembered long after ? And in periods of not feeling love for someone, to diminish, or dreams ceasing at all ? -Not related to make sense or not about the dream, nor to ease of falling asleep-

Burr-Brown also makes it, and their application note is here: http://www.eetasia.com/datasheet/pbDSDownload.do?datasheetID=1000045781&partNumber=OPA541&pdfFilePath=http://www.ti.com/lit/gpn/opa541 Good luck, Miguel

Surface mount tiny leds in small hobby quantities, are very hard to find unless you canibalize defunct equipment. In large quantities, there is hundreds of providers looking for sales, and most have a minimum order. This place may be the most convenient for you : http://parts.digikey.com/1/parts-kws/smd-led

That is the one in my link above, readable on-line. Published repeated times every few years and the last one seems to be in 1984, but I do not know if the last edition contains newer material. Will find out soon. Miguel

Hi. It does not seem to be any of those in the links. I saw such USA printed book overseas around 1980 and had 'modern' formulas and detailed processes to manufacture real products. Still have not located it, but not searched thoroughly lately. edited: added Jene: Try yourself with your techniques and clues you remember on scirus.com and ojose.com and come back with findings. Forget about google and take your time fine-tuning the search. Miguel (original poster) Merged post follows: Consecutive posts mergedThis seems to be the oldest edition (1914) of the book, readable on line - thanks, ojose search engine! - : http://www.archive.org/stream/henleystwentieth00hiscrich#page/n7/mode/2up And I think I located the 1984 edition, going for it. Hope includes 'modern' stuff in it. Its ISBN number is 0877810281 Miguel

Hi. Trying to find out if by mixing a few not-fancy compounds, a thick ink can be made, like the ones used in ballpoint pens. Remember those high school experiments that produce colored solutions... Can they be made in a viscous form? How are ballpoint inks made?

You do need those two 1000 ohms resistors in the circuit. Miguel

It should. Come back with results. Some transistors have the habit of staying on when a 'pull down' resistor is omitted, but go ahead. Miguel

A battery powered cooling device can be as simple as a propeller promoting faster evaporation from the towel surface. A Peltier effect cooling device would also work, if its heating half is also able to cool itself by wind of fan.

A towel presents a very porous and large surface that promotes its moisture to evaporate faster as there is large area of water contacting the air. When water evaporates absorbs heat. 540 calories each gram. That cools the wet towel, and you in contact with it. It is nothing out of the ordinary and well known effect. When you want to evaporate water, you heat it up with a flame, sun rays,... or your warm neck. If you want the same in turbo mode, wet the towel in alcohol. http://en.wikipedia.org/wiki/Evaporative_cooler Miguel

Hi. The first schematic is a theoric analogy for the AND gate. The lamp, relay or load would connect between the 'out' node and the ground (bottom) The positive of your battery goes at the top and its negative to the ground. The second schematic is very wrong. Erase the short vertical line portion above the top transistor that joins the red and black curved wires. The leftmost vertical line is very wrong. Puts a direct short circuit connection between the battery terminals. At least erase the portion from the "0V" up to the lower B switch The bulb won't shine bright as has a 680 ohm resistor in series with it. A led instead of the light bulb would work much better. Observe polarity if you replace it. Anode to the top (+) , cathode to the upper transistor collector. The top horizontal line is where you connect your 6V battery (+); the bottom horizontal line is for the battery (-) Ignore or erase the rightmost extension of the bottom line, (from the 680 ohm resistor towards the right.) Miguel

Thanks, John. OK, understood that the only heat of vaporization is supplied by the amount of heat the litre of water has at the initial temperature. When it gets 'all used up', water freezes. So I have to supply heat if the initial water temperature does not provide the calories needed. Is the heat of vaporization constant 540Kcal/litre also under vacuum ? How do I calculate the amount of heat the 1 litre will yield at a given starting temperature?; Or; At what initial water temperature should the process begin to have all the water vaporized with no freezing ? Miguel

Hi. Lost in space on how to calculate, or how to make a nomogram/chart; please some guidance. 1 litre of water at 20C in a regulable vacuum chamber, no heat added. At what amount of vacuum will the litre evaporate in one hour ? Or, if wanted to evaporate 1 litre in one hour, how much vacuum should be applied ? ============== Now, the water can freeze if the vacuum is considerable ( I do not know the figure), so that should be avoided if evaporation is desired, as if frozen, the 'sublimation/evaporation' speed would considerably decrease -Am I wrong there ? The optimal condition could then be to keep the boiling water from freezing (about not less than 5C) due to vacuum. Am I wrong here ? Is the water freezing at 0 C or at another temperature due to the vacuum ? How to calculate/chart the amount of vacuum that will evaporate the litre of water faster ? Will the litre of water evaporate faster under vacuum if its starting temperature is 80C ? What would be the temperature of the water vapor flowing trough the vacuum pump suction hose ? The X-Y chart could ideally fit initial water temperature, final water temperature, vacuum amount, time, volume evaporated... Thanks for light on any or all of the above. Miguel

Try fiberglass or carbonfiber reinforced plastic foil. Seen it in thinner than a business card, and can be sanded down further. Edited: added---> http://www.protechcomposite.com/servlet/the-40/carbon-fiber-sheet-panel/Detail Miguel

Nope, it is not based on parity, there is no trick, as any player can choose the move. It's mathematics. If anyone wants, we could play a few times right here on the forum. If you want to make it more interesting, we could do a 1 - 3 - 5 - 7 - 9 instead of 1 - 3 - 5 - 7 The simple way ? OK: I III IIIII IIIIIII (Just write the next 'matches' pattern on the response) Miguel