Luminescence

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"CONSUMER ACQUISITION SITE"

Luminescence

Light is a form of energy. To create light, another form of energy must be supplied. There are two common ways for this to occur, incandescence and luminescence.

Incandescence is light from heat energy. If you heat something to a high enough temperature, it will begin to glow. When an electric stove's heater or metal in a flame begin to glow "red hot", that is incandescence. When the tungsten filament of an ordinary incandescent light bulb is heated still hotter, it glows brightly "white hot" by the same means. The sun and stars glow by incandescence.

Luminescence is "cold light", light from other sources of energy, which can take place at normal and lower temperatures. In luminescence, some energy source kicks an electron of an atom out of its "ground" (lowest-energy) state into an "excited" (higher-energy) state; then the electron gives back the energy in the form of light so it can fall back to its "ground" state.

If you lift a rock, your muscles are supplying energy to raise the rock to a higher-energy position. If you then drop the rock, the energy you supplied is released, some of it in the form of sound, as it drops back to its original low-energy position. It is somewhat the same with luminescence, with electrical attraction replacing gravity, the atomic nucleus replacing the earth, an electron replacing the rock, and light replacing the sound.

There are several varieties of luminescence, each named according to what the source of energy is, or what the trigger for the luminescence is.

Fluorescence and Photoluminescence are luminescence where the energy is supplied by electromagnetic radiation (rays such as light, which will be discussed later); photoluminescence is generally taken to mean luminesce from any electromagnetic radiation, while fluorescence is often used only for luminescence caused by ultraviolet, although it may be used for other photoluminescences also. Fluorescence is seen in fluorescent lights, amusement park and movie special effects, the redness of rubies in sunlight, "day-glo" or "neon" colors, and in emission nebulae seen with telescopes in the night sky. Bleaches enhance their whitening power with a white fluorescent material.

Photoluminescence should not be confused with reflection, refraction, or scattering of light, which cause most of the colors you see in daylight or bright artificial lighting. Photoluminescence is distinguished in that the light is absorbed for a significant time, and generally produces light of a frequency that is lower than, but otherwise independent of, the frequency of the absorbed light.

Chemiluminescence is luminescence where the energy is supplied by chemical reactions. Those glow-in-the-dark plastic tubes sold in amusement parks are examples of chemiluminescence.

Bioluminescence is luminescence caused by chemical reactions in living things; it is a form of chemiluminescence. Fireflies glow by bioluminescence.

Electroluminescence is luminescence caused by electric current. Cathodoluminescence is electroluminescence caused by electron beams; this is how television pictures are formed. Other examples of electroluminescence are neon lights, the auroras, and lightning flashes. This should not be mistaken for what occurs with the ordinary incandescent electric lights, in which the electricity is used to produce heat, and it is the heat that in turn produces light.

Radioluminescence is luminescence caused by nuclear radiation. Older glow-in-the-dark clock dials often used a paint with a radioactive material (typically a radium compound) and a radioluminescent material. The term may be used to refer to luminescence caused by X-rays, also called photoluminescence.

Phosphorescence is delayed luminescence or "afterglow". When an electron is kicked into a high-energy state, it may get trapped there for some time (as if you lifted that rock, then set it on a table). In some cases, the electrons escape the trap in time; in other cases they remain trapped until some trigger gets them unstuck (like the rock will remain on the table until something bumps it). Many glow-in-the-dark products, especially toys for children, involve substances that receive energy from light, and emit the energy again as light later.

Triboluminescence is phosphorescence that is triggered by mechanical action or electroluminescence excited by electricity generated by mechanical action. Some minerals glow when hit or scratched, as you can see by banging two quartz pebbles together in the dark.

Thermoluminescence is phosphorescence triggered by temperatures above a certain point. This should not be confused with incandescence, which occurs at higher temperatures; in thermoluminescence, heat is not the primary source of the energy, only the trigger for the release of energy that originally came from another source. It may be that all phosphorescences have a minimum temperature; but many have a minimum triggering temperature below normal temperatures and are not normally thought of as thermoluminescences.

Optically stimulated luminescence is phosphorescence triggered by visible light or infrared. In this case red or infrared light is only a trigger for release of previously stored energy.

HAVE YOU BEEN THE TARGET OF A SCAM LATELY? DON'T LET YOUR GUARD DOWN!

AUGUST 20TH, 2008 - BROKEN ARROW, OKLAHOMA

If you are not on your toes all of time, you could be the target of a scam or con. Last evening while filling up with gas at QT in Broken Arrow a blue PT Cruiser pulled across in front of my truck. A casually dressed black man stepped out and in a hushed voice asked if I was interested in buying a laptop computer. He proceeded to tell me he had three or four of these for sale for $250 each. Claiming they were brand new Sony Vaio laptops. My first question was "Are they hot?" and I informed him I wasn't interested. He pressed on asking if I would pay $200, then $150. "I don't buy merchandise from the trunk of a car" I informed him. He then asked how much I would be willing to pay, and went back to his car, retrieving a package from the back seat that appeared to be a box about the size of a laptop, wrapped in brown paper, taped up excessively with packaging tape, and a photocopied ad from Office Depot advertising a Sony Vaio for $2099. In the process of getting the package from his car, he covered it with a sheet before bringing it to show me.... A lot suspicious... He handed me the package and returned to his car to retrieve a laptop from the back seat, again covering it with the sheet so no one else could see what he was doing. The laptop was an older Compaq, that he claimed a lady had dropped, but the ones in the packages were Sony. He very quickly returned it to his car, not letting me see more than a glimpse of it under the sheet. Meanwhile, I was hefting the supposed "new" packaged laptop, the entire time suspecting a scam more so than stolen merchandise. I strung him along a little while, squeezing the package (it was too lightweight, and compressed easily) Now knowing I was actually holding a package with nothing substantial inside, I told him I might be interested if he showed me what was in the box. He very quickly retrieved it from me, still trying to get me to pay $150 for it, as he gradually put distance between us getting back to his car. That pretty much ended the conversation. I told him again, "show me what's in the box, I might be interested." No go, he got back in his car and quickly went looking for another mark.

I had meanwhile finished filling my tank, and drove to a strategic location in the parking lot to watch him and his accomplice as they drove about the lot, approaching literally everyone coming and going, I quickly dialed 911 and reported their activity, gave a description of the vehicle and what they were doing, stressing that I firmly believed they were scamming people with empty boxes. I waited for police to arrive, but before they did, the vehicle exited the QT, and drove down the street. I followed at a distance, again calling 911 dispatch to report they had moved to another location, near Chili's and Buffalo Wild Wings. Actually, they had gone to the Lowe's parking lot and by the time officers arrived, had already approached several patrons in the lot. As an unmarked Dodge Charger pulled into the BWW lot, I pointed them to the Lowes. Two other marked units quickly converged on the lot, and as the PT Cruiser approached another mark in front of the store, they hit the lights and surrounded the vehicle! Too cool! I watched from the lobby of Lowes as they talked to the "suspects", and got the passenger out to open the back of the vehicle. After some minutes, a couple came out of the store and saw that the police were questioning the pair, and hollered at them "What are they doin'? Tryin' to sell ya a laptop?" One officer motioned them over and asked if they had been approached, to which they answered yes. The officer asked if they would be willing to make a statement, and a citizens arrest on suspicion of fraud. When they said they would, one of the suspects started cursing at them, this just added resolve to the couple, and they immediately made the citizens arrest. (This was necessary because the officers had no evidence of a crime otherwise.) At this point the two were arrested on fraud charges.

As it turns out, the packages were Fed-X boxes filled with newspaper... They had empty boxes, brown paper bags, tape, scissors, and flyers in the back to make more fake packages. Officers also found bolt cutters and a few personal items in the vehicle, along with three or four bogus packages, and the old, useless Compaq laptop they were using as a prop for their con. They did not find any weapons or drugs fortunately, but the passenger had a felony warrant for his arrest in Florida (the officer said that unfortunately, Florida would not extradite). Officers said they also had a fair amount of cash on them, leading officers to believe they were semi-successful with their con game. Both suspects were from Alabama, and the PT Cruiser had Alabama plates. Both are now sitting in the Broken Arrow jail, the PT Cruiser is impounded, and at least for now, they are off of the street.

Do you think those who paid $150-$250 for a box of newspaper will report it to authorities? Probably not.... Wouldn't you feel a bit foolish for falling for the scam? How about the fact that anyone with common sense would know they were about to purchase stolen merchandise, had the package actually contained a new $2000 laptop...

If you buy merchandise, especially new or near new expensive merchandise off the street, or from the trunk of someone's car, for pennies on the dollar, you should know you are about to buy stolen merchandise, and will be supporting crime. So don't do it! Don't be a victim! Report this kind of activity and save some other fool from making a mistake. These are tough times and if we don't stand up as citizens and do our part, then we are part of the problem!

In all honesty, it felt good to help get these two apprehended! And yes, I gave a written statement, and if asked, would gladly testify against them in court!

Virgil

VIRGIL G. RICHARDS

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