Externet

Dry. Applied the 'juice', rinsed; placed above a steamy cup, no fogging. One hour later, placed above a steamy cup. Fogged. Rinsed only, tried again, did not fog. Waited another hour, placed above a steamy cup; fogged. Rinsed and placed above a steamy cup. Partially fogged. Seems the 'juice' needs to be wet and 'fresh' to perform. (forms a thin water film) ----------------------------------------------- Why the reply window shows all greyed lately ? When submitting, shows "Loading" , later shows post.

Hi John. ~12 hours later, placed the mask again above a steaming cup of water. Both sides fogged, the effect is lost as expected. On a windshield under rain, it also has a limited duration. The interesting part on an already wet windshield, is that the compound still 'sticks' to the glass for a good while.

Hi. Sometimes I see a way to grade the topic -or question- (about the quality/interest of the initial post, not the responses) somewhere on the screen. Some times does not show. Where and how works ?

" ...If Externet had a bathtub, he could test the anti-fogging properties on his scuba mask." ---> It is not if it works; it is about which compound in a potato performs as wetter/fog preventer. <--- The potato works wetting a windshield under rain. The potato works on my bathroom mirror, it does not fog. For "...I have been told that letting people solve problems for themselves is good" 'Potatoing' the right side of the mask , prevents fogging. Confirmed.

Hi all. Is the sun position at longitude 000 00' 00" the exact geographic south at 12:00:00N time every and any day of the year ? Does the seasonal earth rotation axis angle alters anything regarding azimuth ?

The part in potato juice that draws my attention is; when sliced, the amount of juice deposited smearing glass, has to be about one drop, if that much. and performs. And the drop of juice is ~78% water. So a 22 % minuscule amount of a drop of remaining chemicals, performs. And who knows what percentage of that 22% of a drop is responsible for the anti-fogging/wetting effect of interest. And oxalic acid not mentioned here :

Aiming an antenna earlier today, found that my believed accurate 'Geoclock' software and three other calculators differ. In order above for the same time: NOAA: 189.89 USNavy : 180.2 PVedu : 236.66 Which one should I rely on ? I just want to know at what time the sun is at azimuth 180 for my location.

Hi. Disemboweled a defunct CO detector (not a smoke detector) to find out what the sensor would be like. And got There is a cylinder the size of a fat AA cell. has only one ~0.1 mm hole behind a tightly packed dessicant sachet blocking it. Seems filled with liquid. The incomprehensible part is how can CO easily enter such tiny and blocked orifice promptly to signal the alarm, in still air... By searching, seems it is a Pasted from the web : "Electrochemical Carbon Monoxide DetectorsThis is an electrochemical cell that is designed to produce current in relation to the amount of carbon monoxide present in the air. Carbon monoxide is oxidized to carbon dioxide at one electrode while oxygen is consumed at the other electrode. Sulfuric acid is the usual electrolyte that separates the electrodes. The current triggers the alarm or can even be used to quantify the amount of carbon monoxide that is present." And it looks like ----> http://images.teamsugar.com/files/upl1/1/12981/01_2008/22cc51ad22642d81_CO.jpg Do you know the operation principle/rationale of the sensor ?

Thanks. Even if parsley works better, still would prefer the potato to avoid the mask from fogging. Liquifying parsley and eye-drop bottling it... I hope remembering the task next time. But smearing a potato works. Zero beading. For about 2 hours under the rain. Typical easy way we divers do is smearing deep throat spit on the glass. Works well too. ! Found the potato listed among the 'products' ----> http://dualsportalchemy.com/2013/08/tip-keeping-your-goggles-fog-free/

OK. Flexible skegs added.

Neat ! Thank you !

From my grandpa era tricks; when the windshield wipers stopped working, rubbing a split potato onto the glass allowed to see very well until those old vacuum motors/hoses get fixed. And it works great. What is in that juice? Some surfactant ? Never tried as defogger for my scuba mask. Would it work ?

Seen some orientals propelling their small boats with a single oar 'yuloh' at the transom, on 'Z' motion. ----> http://www.simplicityboats.com/1Scullings.jpg Would there be an advantage of the oar paddle being flexible, as a fish/whale tailfin propulsion, not for 'Z' motion ?

Concentrate your efforts towards the shape and size of the pole pieces, to fit and focus the application of magnetic field to the intended part area. Sawing off a choke core to create a suitable gap and feeding it with DC should allow evaluation of results. ----> http://image.made-in-china.com/4f0j00kBETYdGJaWzH/Toroidal-Air-Core-Choke.jpg A handheld tool with a momentary 'on' pushbutton is what I envision, with a removable and spare battery pack that can be recharging. Adapting the electromagnet head to one of these instead of the lamp is a good start : ----> http://ecx.images-amazon.com/images/I/71RVfwKZkHL._SL1500_.jpg For the question "b) Increase the current flow - or otherwise increasing field strength" To increase field, what matters is Ampereturns : More current, more turns, less resistance as in thicker wire, more volts. But there is a missing factor: focusing the field only to where it is needed can make a difference ! ¿? ----> http://www.intechopen.com/source/html/47744/media/image12.png

A subject of extreme interest to me. My daughter was born with strabismus; had her first eye muscle surgery at about six months new. And several after. Wore alternating eye patch at the beginning, Fresnel lenses later. The point was to prevent amblyopia, and keep both eyes active even without stereovision. She avoids driving as conscious of the impairment, but says she sees well. A comment to expect as she has never seen in stereo. Took her to the best opthalmologists in the planet. It is a brain problem, by the optic nerve chiasm, inoperable as far as I understood. I designed and built electronic LCD shutter glasses to provoke the no-loss of sight in the non-dominant eye, and were shown/presented to professionals of the specialty before use. All agreed that would not do any harm but of unknown therapeutic results as such thing was never tried nor exist before ~1995. I pushed my daughter to wear them while watching TV. She did not loss the use of any eye, but am not claiming due to wearing the glasses. The shutter glasses were taken to Germany for evaluation by specialists, and their interest somehow faded, lost track. Still have them, prototypes and finals, if anyone has the urge to borrow these, specially for a kid under 11 years old, I will gladly share them. Contact is my username at inorbitdotcom Would like to see a drawing as in post #3 by Endy but made by someone with that condition, or a clear explanation.

Most consumer and professional electronic equipment already works with dual (+)15V , (-)15V rails, and ground DC supply. The operational amplifiers in circuits mostly are made to use both 'phases'. Even computing equipment uses ±5V, ± 12V. If that is what you meant.

Found this second paragraph now :

No way. The short and long green lines are at 45 degrees, and both turn together by the same bezel. Being declination (magnetic to true bearing) would be only for specific isogonic locations with 45 degrees declination.

Hello all. Can anyone explain what are the long and short greenish lines for in this compass, or how to use them ? Many sites on the net without clear explanation. They can be rotated with the bezel, it is not about the black fixed line aligned to the sight not shown in the picture. ----> http://www.galaxyarmynavy.com/prodimages/400-big.jpg

A group of violins playing unison the same note on an orchestra... The particular vibrating string emitting the sound cannot be perfectly synchronized from one instrument to another and another. Why there is no perception of tone nodes/antinodes constructive/destructive interference/interaction, but a smooth equal pleasant sound ? When the string is moving 'upwards' in instrument 1, the string in instrument 2 can be moving downwards. Plus any tiny-tiny deviation in tuning the instruments should create noticeable interference. Or the distance from the ear to one or another instrument... Reinforcement or cancellation is not perceived. It sounds just as a majestic sound purity. Why ? I can understand that if the unison instruments heard are from playing a recording, such interference effect should be not perceived as the microphone had a fixed location and picked whatever picked. But live performances sound just superb for a group of equal instruments. For violins or saxophones or whatever at unison. It is like having independent electronic tone generators at unison and their speakers at different spots. Their propagated waves do interfere. Or, is it only perceived if the listener is in motion in the performing room ?

This link has resided in my bookmarks for years ----> http://www3.telus.net/farallon/ As I have much interest in innovative desalinators. Discussing things with its author, a doubt of its engineering surfaced, related as performance differences being vented or not...

Thanks, John. Then, I take constant DC lit having more average power than pulsed, the pulsed LED room will be perceived as dimmer. As expected.

I can see an assumption that plants transpire pure water vapor. What compounds are actually transpired, exactly ?

Hi all. LEDs operated in pulses over ~30 Hz are not perceived by the eye as pulsing but continuous emission of light; is the lumens emitted same in pulsing effect than if ran on DC at full power/constant current ? (pulses being also at full peak power) Operating LEDs in AC, the emission of light occurs only when the LED voltage Vf threshold is surpassed, and at the rest of the waveform, they are 'off' If the frequency is high enough, the 'fast intermittance' is not perceived. Do sensors to determine/measure luminosity of a light source respond with different lumen figures in pulsed and DC current ? In other words, constantly lit LEDs produce more lumens than pulsed ones ? To the eye, will a room feel brighter if not pulsed ?

Seen that a long ago. Very well made. For a quicky, try with a frisbee on a shaft using the inside of its rim for the ball. Another with disclosure : ----> And the most theoretically interesting I have found : ----> Lots of efforts and time spent by hundreds of tinkerers after the same dream...