Externet

What about a metal foil at the bottom of a tub/pond as one electrode, submerged in ONE liquid with floating whiskers/wires ? (instead of the two nonmiscible PN junction liquids)

Benefit ? Just a shot in the air, as may be possible to make such thing at home with materials easier to make than cristalline silicon and thin film technologies. The transfer part, if an electrode is at the bottom of the tub, under a couple of millimeters of fluid A, and electrode hairs immersed in fluid B layer above. The collectors cannot be a deterrent ! Put the thinking hats on !

Yes, is the clear gel soil for growing plants, when - I believe- hydrated with hydroponic formulas. The poisonous part am not sure. Perhaps when degrades over time. Found this, but hebrew to me : http://www.cellmigration.org/resource/imaging/ppt-pdf/polyacrylamide_gel_fabrication_flowchart.pdf Miguel

Come on, enough skilled, experienced and smart people in this forum ! Come up with a fluid in a tub -or two layers of nonmiscible fluids, or whatever your knowledge yields- that when sun-bathed generate electricity at its electrodes. It's about time... Miguel

Thanks, Herman

Hi. Any way to make such thing at home ? Is it a complex task ?

How would a diesel engine behave if fueled by unprocessed rapeseed oil ?

When was the last time you knew of a shipment of medicines, food, aid of any kind sent to any country in distress by natural, or political, or starvation, or whatever reason... originated from any of the superrich OPEC countries?

Do viruses, bacteria, and the microbes that cause illness to humans get their share of problems too with parasits or sickening agents other than antibodies ? I would love to see viruses with thermometers stuck in their mouths, keeping rest...

Hi YT. Go to the wreck yard and canibalize the headlight of a BMW. Cannot remember since what year they have a central lens like the one you are after. I have a couple but mailing may not be fast/convenient as you can get them there. Let me know if yes. They are plano-convex "D" as you want ; 60mm + 7mm for holding rim = 67mm ⌀ total, real good glass; 22.1mm thick; whatever diopters that yields. Miguel Edited-added : other lens sources are the old large copy machines, projection televisions, slide projectors at recycling places.

From what I know, early humans were gatherers and their diet was mostly fruit. At what point fire got into the mixture and some foods were needed to be boiled/cooked/burned? What happens if not cooked? Take peanuts or potatoes as example; how nutritive/edible are they raw against cooked in comparison to other nuts/roots eaten raw ? Is it true yams are very poisonous raw?

Hi. Hair turns gray or grows grey? I have not seen dark hair at the older top end and grey at the newer bottom; or does it happen? If grey hair never has a dark top section; does it mean that it grows grey from the 'new' start ? Then, if it grows from the scalp as grey, it has to be from a follicle that previously lost its dark hair to the root, right ?

Thanks for the responses... Do you know of any oil type with a low amount of reacting oxygen / moisture that you can recommend, please? or process to de-oxygenate it ? Heating it up to evaporate moisture ?

Hi. Can the surface oxide layer be permanently removed if a piece of the metal is scraped while submerged in oil -and kept in it- ?

What should be expected from vinegar + baking soda? And a pool chlorine tablet + alcohol ?

Trying to find how to put together one deflated 'party' balloon with a few grams of water in it and a chamber or packet with some compound also inside, that due to mechanical jerk they mix and produce a gas, perhaps CO2, so in less than a minute would inflate to something like 5 to 10 litres. What household or simple compounds could achieve this ? Would baking soda or baking powder or a more energetic something work ? Ideas ?

Thanks !

Hi. Would polar coordinates be preferred for calculations on a heliostat mirror aiming? Get about a metre long piece of string, anchor one end to anything, call that T 'target' and also anchor about the middle of the string to anything else, higher or lower, being that point M -mirror- Grabbing the end of the string point S -sun- , a solar ray path can be visualized by moving the string along a plane. Now, what are convenient reference axis to use for calculating the azimuth and elevation the mirror M should aim so S always illuminates T ? Or, any other suggestions on how is it done ?

What is voltage produced by a galvanic cell made with carbon and magnesium electrodes, on a ClNa electrolyte; ? If the Mg is replaced with aluminium, what would be then the voltage generated ? What atomic data of the Mg, C, Al elements is used to determine/calculate the voltage generated ?

Hi all. Looking how to calculate the power developed by an undershot water wheel spun by a laminar flowing river in function of -Flat paddles submerged area, -Speed of river ignoring friction losses. http://commons.wikimedia.org/wiki/Image:Undershot_water_wheel_schematic.svg Thanks.

Thanks !

How is it called? It is shown usually in the Pacific ocean -for available space-, I believe has something to do with (solar?) declination trough seasons, it is an elongated "8" What does it mean ?

Hi. 1.- Go to a "Home depot" type of store and buy one. If you can beat by far their less than $2 price TO THE PUBLIC for a sprinkler, then keep thinking. 2.- A patent is highly likely to drive you nuts waiting never less than 2 years until issued IF granted or any other sprinkler manufacturer does not bite you. 3.- The ONLY thing a patent gives you is the right to sue. To sue, you need a lot of money to feed lawyers. Probably more than the amount you need to start production with no patent. 4.- If after years of sweat and tears you start production protected by a patent, the chinese will copy it for a fifth of the price if the idea is truly brilliant. Then, just MAKE them and sell them to all related stores at your reach -now-. Good luck. Miguel The same thing happens to me often. After typing a response, and "Logged in" showing, the submitted message dissapears unretrievable. Just highlight the text and copy it before clicking "Submit reply" Then you can retry pasting.

Hi all. A young fellow started work as an electronics technician a couple of years ago in a factory and by whatever reason management did not train him on the products, by his own means slowly learned and found out the innerworkings of the products he handles, meanwhile struggling and appearing unfit for the job. Another technician to do similar activity was hired. Should the now experienced technician on his own train/teach/share/guide the new one with all the knowledge management did not care to supply ? If yes, the new guy will appear more competent for the job. If no, the company suffers. And other implications depending the point of views of each technician and management. Suggestions ?

If the audio signals from two microphones are fed to a differential amplifier, its output will be only the audio which is sensed in real time by one microphone more than by the other. That way, equal sounds reaching simultaneously to both microphones will not be amplified by canceling each other due to phase inversion of one by the differential amplifier. Success depends much of microphone placement and directional characteristics. In open environment, sounds sources headings play a role in the success of the cancellation. A "voice canceling schematic diagram" or "vocal remover..." search could yield further details. Miguel