Externet

Here:

http://en.wikipedia.org/wiki/Piano_key_frequencies

And should be the same for all instruments.

Japanese and some oriental instruments are tuned at different frequencies; this site may be of particular interest for your signature:

http://www.math.nus.edu.sg/aslaksen/gem-projects/maa/Early_Mathematics_in_Chinese_Musical_Scale/index.htm

No, and thanks for the links.

Occurred to me that those fogger gadgets on novelty stores could make a carbureted / intaking fuel much more efficient, but have not tried/experimented with.

To apply the concept to modern injected engines, some 'injector' device would have to be developed to repeatedly feed batches of fog fuel instead of the current spray.

It may be simple when injecting into the intake valve area, but much harder to deliver directly into the pressurized combustion chamber.

In some electronics forums, there is an ocassional request on how to home make water foggers for whatever use; and I forget now where there is data about frequency, type of convenient transducers and other details.

Edited- added -> http://www.mainlandmart.com/foggers.html

( some kits to play with )

Miguel

Merged post follows:

A nice find :

Miguel

Some devices used for delivering insecticides into open areas operate on "thermal" principle... How is that in detail ?

I do not think it is just matter of heating-up the fluid under an air blower flow.

Any light please?

Example : http://www.dynafog.com/international/foggers/

Miguel

Ultrasonic 'fogger' devices would increase efficiency by 'atomizing' fuel better than any electric/magnetic field

µwave ovens do not vary their magnetron power; their duty cycle (time on and time off) can be step-selected in the medium/low/defrost setting.

Yes.- Is it Na6 P6 O18 ?

and another type, mixing

42% Sodium carbonate

28% Sodium sulfate

23% Sodium citrate

Do these make sense ? Any others ?

Hi.

There is household products in liquid and in powder forms intended to be added to water, like in a laundry machine; but NOT to be used into water softening equipment. They are referred as 'salts' . What are these compounds ?

Not in powder, but a discarded electric water heater can have a lot left in its galvanic rod. Unscrew it and a Mg bar will come out.

A Volkswagen air cooled engine block + transmission housing from the sixties is 97% Mg.

Miguel

A water pump, probably piston driven, that left floating at the side of an anchored boat, would use small 10 cm crest-to-valley waves to pump water 5 metres high to a reservoir in the boat with a 3mm hose ? -Nothing attached to the boat hull, that would be easy-

A submerged 'umbrella' and a float, connected by piston/cylinder assembly ?

A hinged float ?

The flow can be small, but could it be made to rise 5m ?

It would need a lot of force to push the router through material at 0 Watts or 0 rpm; so it has to be very important.

Hi.

Am missing too many things with the growth of these crystals; can someone clarify details please ?

As the molten bismuth is slowly cooling, do the crystals form embedded in the liquid, under the surface, as 'a diamond in a glass of water' ; Is that right ?

Pouring out the molten metal leaves the solidified crystals in the pot, attached to portions of solidified metal ?

How come the 'being poured out' molten metal does not leave particles and 'dew' attached to the crystals crevices ? They look soooo shiny and clean and smooth !

Do crystals grow only while submerged in their slightly hotter surrounding metal ? After the molten metal is drained, the crystals do not continue to grow, do they ?

Does it make sense to say the longer the time waiting to pour out the molten metal, the larger the crystals would be ?

But it is mandatory to drain before all becomes a solid piece, right ? ... Like 'the diamond being now captive in ice'

If the melting pot had a cover, (with little air gap) there would be less/no formation of the grey layer on the surface because of less oxygen to produce it, is that right ?

Is cooling preferred to start in the bottom of the core (if it was possible), and keep the pot walls hotter to achieve a better ideal draining?

Edited: a nice site ----> http://www.amazingrust.com/Experiments/how_to/Bismuth_Crystals.html

Thanks.

Hi all.

Written English and chinese seem to me, a native spaniard; very memory intensive comparatively.

In spanish, you do not have to memorize how to spell, words never heard before are easily written with no previous knowledge. A new written word can be pronounced properly with no previous knowledge. It is a fonetic language.

You may not want to hear me to say the simple word 'focus' with my accent. That triggered this post.

Well, ¿ would the forced memory exercising due to a language that is not fonetic play any role in better brain capabilities in lives of non fonetic speaking people ?

Miguel

I think you mean in parallel. Series would increase the voltage, and therefore the current. Parallel increases capacity.

---> Wrong. heating elements in series do NOT increase voltage nor current. They increase resistance

The only problem I see with this, is that you would have to carry around the equivalent of a car battery, which is why I see this as unfeasible. Perhaps a higher resistance heating element.

---> That is what several cigarette lighters in series are: a higher resistance.

a car battery would be if you want the heater on for many hours, possibly days.

I like the chemical way from YT.

First time bee/wasp stings do make you feel much better the day after, but the next times you get stung the effect diminishes.

I do not think it cures anything.

Hello.

An automotive cigarette lighter heating element and a momentary pushbutton switch can serve well for your application. If drains the battery too fast, try a couple of them in series to get less temperature but more time.

Or remove the heating wires and wrap them properly around the CO2 receiver.

Questions about these bismuth 'levitators'...

Does the thickness or mass of the bismuth affects the amount of repulsion ?

Can the same effect be achieved making the bismuth be the one floating above a magnet ?

Hi all ! and thanks for the replies to the related preamble post "Metal under the hot sun" found here:

http://www.scienceforums.net/forum/showthread.php?t=35416

Let's imagine...

Metal pipe(s), say 10cm ⌀, vertical, blackened, say 3metres long, vents at the bottom, exposed to sun heat.

A nozzle misting seawater inside from their tops. Flow calibrated to always have a little brine draining at the bottom. A shaded wind cooled condenser at the top of the pipe(s) to collect evaporated water.

There is room for some improvements as transferring the condensed water warmth to the incoming cool seawater with a exchanger, etc. but let's ignore those. There is a need to care for simplicity and cost.

There is much more to ideas, there is calculations. Where do I start to speculate about productivity ?

Miguel

If there is no heat capacity, no thermal conductivity, no mass and no density in the formula; I would say the plateau temperature reached calculates to the same figure no matter which material is under the sun.

That does not make any sense to my ignorance. Where am I goofing?

Does it mean wood and iron will have the same temperature but touching the wood will not burn because its amount of heat conducted to the skin due to poor conductivity will be dissipated sooner and not 'burn' ?

[ The 1m^2 exposed surface is a good number for the analysis, all the different material plates under the same sun being that area, each being thicker or thinner to yield same mass, all painted same flat black and resting on the same insulation ]

Miguel

Thanks.

Let's see if I understood...

Specific heat capacity (from Wikipedia) :

Iron = 0.45

Aluminium = 0.897

Lead = 0.127

Copper = 0.385

This means that plates of the same dimension exposed to same sun, all kept say on top of a piece of insulator; the lead will increase its temperature the highest, and aluminium the least.

and for thermal conductivity :

Aluminium = 237

Lead = 35.3

Iron = 80

Copper = 401

Means that if all are at the same high temperature, touching copper will likely burn skin faster because transfers (conducts) its heat faster than lead.

Is that right ?

Does anyone know about rubber behavior ?

What material presents in greater magnitude the property of shrinkage when warm -say 25 Celsius and expand when cold -say 5 Celsius ?

Thanks.

OK, it is truly hotter, got it. Yes, it has to be, feet at 37 Celsius get blisters on pavement, and fried blisters on a steel plate. That can reach a guessing 70 Celsius

Now, the metal mass has nothing to do with the temperature after reaching plateau, right ? (am not saying amount of heat!)

What material index, property, constant... tells which metal will be hotter under the same sun?

Stainless steel, plain iron, aluminium, brass, lead... which will be at the higher temperature ?

And if all of the above receive the same flat black coating of paint, would they all be at the same temperature or still differ ?

Sixty Celsius is about the maximum you can handle without burning your hands...

That piece of metal left under the sun, or a car bumper, or the beach sand can burn your skin but the ambient temperature is only 30 Celsius.

What is going on ? How does the metal gets way hotter ? It is not only the thermal conductivity from the material-to-skin; it is truly hotter. Or seems to be

There is no carburettor to modify in a diesel engine; and to my opinion the abbreviations are the degeneration of a language, and have no temperature.

Sooo... it is not carbohydrates modernized...

Miguel