Externet

Hi.

Do not know about your radiotron CRT , but I may be of help. Is there a particular number for such tube?

----> Look trough the glass to the connections of the four pins, the filament should be entering into the center of a small metal tube, and you already identified them as it glows.

The other two may be cathode, a connection to the small metal tube. The last may be a grid, there is a chance you can see trough the glass the actual grid of ultrafine wire.

Applying 300V instead of the full rated 500V should produce some indication of the tube being functional. I do not know what you mean with PD.

Miguel

Checking prices of the stuff, they are absolutely absurd.

If a couple of cubic metres are needed, it's bankruptcy, and its only about 30 Kg. of material

Can something similar be made in a backyard ?, does not need to be a superb product, just similar to that extremely light white packing material we all know, polyestyrene foam.

Miguel

Hi.

In many flavors :

http://www.helmets.org/fourwhel.htm

Miguel

Been there, done that, and it is not always convenient.

The oven solution does work, a butane torch on the solder side works, slammi ng the board at the right melting moment; removal by hand works...

The best way for me, is to keep the parts as they are on the old boards, and remove the ones as needed. Will not need bins, saves a ton of work done to zillion parts that you will end using perhaps 2%, 90% of parts removed by 'brute heat' will have solder splashes everywhere on them, requiering more cleanup work.

And, complete boards provide a bonus, you can saw-off complete operational sections or stages instead of building them.

Miguel

Thanks for the responses

Why can't the latitude / longitude information be applied retroactively?

 

------> I would say that is not a task for a thousand pictures every day and having to return to port to do hours of editing. It is for search and recovery; not mapping.

 

Why are you using a video camera to take a series of still photos?

 

-------> That is waterproof to 100 m on hand, and gives real time monitoring. A digital camera for still pictures, good to 100 m, with coaxial video cable to monitor in real time at the surface... have not seen one yet.

 

By using timestamps, you can correlate the timestamps on the GPS data with the timestamps on your photos, and thus apply the latitude / longitude info retroactively.

------> Naaaah. The photos would hardly have time stamps a second apart, it would be high speed bottom scanning.

 

This can also be published in the form of a GeoRSS PhotoStream

------> That I do not know what it is. I will search for it.

Miguel:-)

Hmmm... I would need to be smarter to understand the thingy.

The camera is a video camera, not a photographic camera, no time stamp in any EXIF, ant time is irrelevant. The video would be captured as individual pictures every certain amount of time triggered depending on the speed being towed to take pictures 'back to back' or properly said, sequential without overlap nor gaps.

And every frame has to be saved with its Lat/Long/heading as 'subtitles' to the hard drive, no posterior editing/adding/insertion of any GPS logs onto the frames.

The "run a script" does it mean running a program? Made with basic, visual basic, C... ? How to 'tap' to the GPS data entering the computer with such program ?

Another data to be superimposed as 'subtitles' to each frame is from a depth sensor.

I was a programmer too long ago to remember how to do it now.

Miguel

Hi.

If I have a global positioning satellite receiver GPS on a laptop USB port, and also a video input fed to the computer;

How to stamp latitude, longitude and heading on each video frame recorded in the hard drive as to log images location for a towed submarine camera ?

To make it harder; if the camera is towed 100 horizontal metres behind the boat, how to compensate the stamped readings for accuracy at all headings ?

Miguel

For ice cubes to stick, their mating surfaces have to be wet, and no need to press them.

The only place an ice cube is at 0Cº is at its surface if wet.

Inside is below zero, up to waaaay below zero. This is something usually misunderstood.

For a while I was daily buying large quantities of ice blocks to preserve seafood, and on a day I decided to ask : "What is the temperature of the ice you sell" ?

Many idiots responses at that place was 'zero degrees, of course'.

If it was 'zero degrees', it would melt in seconds.

Joining ice cubes freeze their wet joining surfaces as the heat at the wet surfaces is quickly drawn by the colder core of the cubes.

Miguel

May not the best place to post the subject, sorry, but :

I have never lived in a house with a fireplace. Am a total ignorant on all about them. Planning to install a cast iron freestanding one on a vacation home that has a brick chimney with a ~8" duct inlet, and i wonder where does the air needed for combustion comes from ? If from the living space ; windows and doors must not be 'airtight', must allow some air to leak in to supply the burning ?

If very cold outside, any supply air entering would work against the desired heating.

If airtight, would the fumes flow freely to the chimney ?

How does it work? Thanks,

Miguel

A sound wave propagates at 340 m/s ; air from a fan across may move at say 3.4 m/s for easy figures. We have 100:1 ratio.

A wavefront from a stone thrown on a river may propagate at about 50 cm/s ; for the same ratio of 100:1 would mean the current flowing at 5 mm/s -relatively very slow - With such speeds, is easy to visualize the wave will reach the shore in front of the thrower in good intensity.

Perhaps that (ratio) is why the sound does make it across the crosswind. If the river was much, much faster, as 1m/s , the wave would not reach the shore in front of the thrower, but way down the river. (equivalent of sound not being heard) Seems a fast enough air speed would prevent hearing the sound. Just trying to find an explanation.

Miguel

Alan - Not here to kick any ass, and less YT's . Am here to learn.

Just another point of view perhaps more visualizable than audio and air. If the waves reach the stone thrower's shore, should explain the independence between both medium and wave propagations. YT's question is a good valid one, and electromagnetic waves and mechanical waves do not behave equal.

Miguel

A similar case would be

Would a stone thrown on a river make waves that will reach the shore anyway even when the current is transporting the water mass down the river?

I read some explanations and definitions, still do not have it clear. Any simpler wording from any of you, please? (Nuclear magnetic resonance spectroscopy)

http://www.cis.rit.edu/htbooks/nmr/inside.htm

http://www.scirus.com/srsapp/search?q=%22Chemical+shift%22&ds=jnl&ds=nom&ds=web&g=s&t=all

From what I grabbed; when exposing an element to a magnetic field, its resonant frequency changes (shifts) certain frequency. As for Au, it is 1.712690 MHz. For Ag is 4.653623 MHz, ...

Now,

-That amount of shift corresponds to a fixed reference amount of field, say 7 Tesla. ?

-Is the shift less for a lower intensity magnetic field ?

-What are the Ag, Au resonant frequencies without the shift because of the field, or at its 'rest' condition ? Higher or lower Hz amount ?

-Is there a 'decay time' of the shift after removing the magnetic field or is it instantaneous ?

Miguel

Get this one, dismantle it completely; you will have all the parts to make one by putting it together again, for the price of a book to learn how to make one:

http://www.rcisland.com/nano4k_b.html

Miguel

Search for a video "Perendev motor"

Miguel

How does it work? When it does not work?

Oily rag, on a corner, no ventilation, hot weather...

What if not a rag, but a newspaper, or a soaked piece of wood with transmission fluid instead, or wet with vegetable oil, or not hot, or breezy ?

Is there critical key conditions for this? Is it consistently reproducible under controlled conditions?

Miguel

Your best option is a compressor from a discarded refrigerator or airconditioner. Usually free, it really sucks ! -As much as you need, and available in many powers-

Miguel

Hello all.

Many years ago, I used the services of a guy that removed all the glass from my car (except front windshield), and dyed them smoky bronze.

His explanation consisted in carefully pouring (not spraying) his 'magic' recipe on the inside surface, kept the glass at an angle to let the excess drip and took a few hours to dry. Yielded an optically clear and smooth, scratch resistant hard finish. No bubbles, no streaks, no voids, highly wetting/bonding

It may had an unintended -or intended- bonus of blocking IR.

What would you suggest to do such, mixing some automotive clear coat with what dye/ink or something else ? Would proper spraying work well too ?

Miguel

Interesting...

http://www.flixxy.com/alternative-fuels-research.htm

I have a problem with all this...

Two identical balloons, inflated to exactly

-the same volume, with the

-same shape, and

-same roughness,

-dropped from the exact same height

-at the same time,

will not touch ground simoultaneously if one is filled with air and the other with water.

No way.

Miguel

A solar energy architecture book I have uses river stones exposed to direct sun all day.

"Portable", cheap and with great heat mass. The spaces between a wall of them allows circulation to withdraw the there-heated air into a dwelling.

Miguel

Being a science mistery and also fact, I can only guess that has to do with the speed of heat transfer, by temperature gradient dt/ds.

The greater the temperature differential per unit of distance from the core of the heated water to the heat absorbing cold surfaces, the greater the 'motion' velocity of heat. But unable to elaborate on this.

Pouring the same amount of same water samples

-in deformable identical closed containers,

-then warming one up;

-and then suspending them both in a freezing chamber

-with no internal humidity

should get rid of the uncertainty about dissolved gases, evaporation, influence of intimacy of contact with freezer walls, and damp air affinity to

one of the containers.

Hope it has been tried that way...

Nope, cannot do it at home to try.

----Also read somewhere that to melt ice from a windshield, cold water works faster than hot. Is that related to the same effect

Miguel

Hi all.

What is the pressure the ice would exert to a rigid hermetic strong enough container if fully filled with water and exposed to freezing ?

Miguel

the silicone probably won't move under 3bar, ........).

Thanks.

Why do you say "probably" ?

Do you imply that if the water pressure is 100 Atm instead of 3 Atm the behavior would be different?

Miguel

Hi all.

If a lenght of empty (with atmospheric air) aquarium hose is plugged with beads of silicone sealant at the ends; and placed inside a plain household water pipe...

When the water pipe is placed in operation, at say 3 Atm water pressure, the hose inside will contract/deform due to the pressure.

Would the plugs at the ends tend to burst outwards or inwards or will not be affected at all ?

Just want to confirm am not missing something here...

Miguel