dor123, This tube is still functioning, the phosphor is still fluorescing. (Albeit at a level less than the manufacturer intended.)
Tubes postulated to be air poisoned
exhibit almost no fluorescence at all and get very hot.
I have made the postulation that the effect shown at the other end of the link above is due to air poisoning, the correct way to prove or disprove this postulate is by experiment. If the results of the experiment agree with the postulate then the postulate becomes a theory.....if enough peer reviewed experiments are performed that agree with the original postulate
then it effectively becomes something so close to fact that it may as well be considered as fact for all intents and purposes. This is effectively how the scientific method works.
If the results of experiment disagree
with the original postulate, then that postulate is abandoned and either another (different) postulate is offered by the same source or different postulates from the peers of that original source are made and, again tested by experiment to see the experimental results agree with and support the new postulate. If so, the new postulate (mercury starvation) becomes a theory and, eventually, with enough peer reviews and experiment, fact.
At present insufficient experiments or peer reviews have been conducted to render and statements of "air poisoning" or "mercury starvation" ineffectual and fallacious. (One low resolution spectrum does not constitute sufficient experimentation.)
So, again, "for the cheap seats"....
that the observed effect of low luminous flux, high operating temperature, lack of phosphor fluorescence and alteration of emitted spectrum are as a result of a few ppm of air permeating into the tube through the meniscus seals at the exhaust tip(s).
I also postulate
that the high bulb wall temperature is due to polyatomic species, i.e. N2 and O2, carrying rotational and vibrational kinetic energy to the bulb wall and imparting a significant fraction of it there by inelastic impact with the inner surface of that said bulb wall. (Monoatomic species, i.e Hg, Kr, Ar, are incapable of vibrating or rotating.)
I also postulate
that the electrical impedance of the tube is altered in such a manner as to draw more power from the available electrical supply in order to justify the ultimately higher bulb wall operating temperature.
Other members of LG (including yourself) have stated, (presented seemingly as fact), but accepted (by me) as an untested postulate
, that the observed effects of low luminous flux, high operating temperature, lack of phosphor fluorescence and alteration of emitted spectrum and electrical impedance are as a consequence of either mercury loss by some mysterious process or adsorbtion onto lamp materials of high surface area, presumably the phosphor as the most logical culprit.
If so, ask some questions....
Why is the mercury not adsorbed into the phosphor (or any other lamp parts of lesser surface area for that matter) in every other tube which functions as its manufacturer intended?
Why do such low luminous flux tubes get so hot? Postulate a mechanism (in the plasma) to account for the high bulb wall temperature. (Or have you never gotten close enough to such a tube in operation to touch it and feel the heat.)
How is the electrical impedance of a tube so afflicted, effected?
Does the alteration of electrical impedance account for the delivered energy to account for the observed high bulb wall temperature?
What does the spectrum (high resolution, (>1nm/mm))of a tube so effected reveal?
Are there any broad (c10-30nm wide) polyatomic, (molecular) emission bands in the said spectrum?
Is there an almost total absence* of atomic mercury emission lines in the said spectrum?
*i.e. Mercury resonance lines at 186 and 254nm have been quenched by more than 90% and visible emission lines of mercury have been quenched down to a similar intensity to the emission lines of the cold-fill inert Gp-VIII gas.
Is there an almost total absence* of very broad phosphor emission bands in the said spectrum?
The postulate of "mercury starvation" does not address ANY mechanism to explain the high bulb wall temperature. My postulate of air poisoning addresses this issue at a plasma physics level.
In order to answer most (if not all) of these questions one NEEDS to study the tube CAREFULLY on a laboratory bench, not up in a troffer on the ceiling of a school. shopping centre or train station!
Your spectra's resolution is so low one is unable to resolve the lines of Krypton. (Bright) Mercury lines, (437, 546 and 580nm can just be made out as can the green triphosphor band, but barely. One would have no nope of seeing any Group-VIII elements' lines apart from maybe neon. The presence of mercury lines disproves
your postulate that this in "mercury starvation".
I have urged you to fit your spectroscope with a slit to improve the resolution, but, so far these requests have fallen upon deaf ears.
Spectroscopy is probably the most convenient and accessible experimental method LG members could use to resolve this issue of "mercury starvation/ air poisoning". But it takes two things...
Access to a tube so effected...
and, access to the spectroscopy gear....(and, no a DVD alone does not posses the resolution).
Another, even simpler experiment would simply involve measuring the tube's current and voltage drop with a True R.M.S. multimeter and back-calculating the impedance, of even simpler, comparing the readings with a set of readings made on a tube of the same type and ratings not so effected.
When I am in a position to get one of these effected tubes onto my bench, I will be running as many tests as possible on it to see if they agree with my postulate. In the meantime the offer goes out to any LG member with access to such an effected tube (and preferably one of the same type, rating and manufacturer that is NOT so effected, to use as a control) to carry out those tests for themselves and post the results.....i.e. peer review my postulate with experiment.
I think you should check the difference between a, "big fat lie" and a postulate/hypothesis before using such emotive terminology in a private message! And don't blame it on the cyber translation from Hebrew to English!
I feel you are surrcombing to peer pressure and simply "following the mob" ...." because they all say it, it must be true" ethic of which most of us humans are so afflicted, rather than turning to first principles and extracting the true answer form the only one who currently really knows the correct answer...THE TUBE ITSELF!