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anilajacka

Posted:
2019-10-16 09:13

Light Emitting Diodes (LEDs), “semiconductors that emit light when zapped with [positive polarity] electricity,”[1] are on the verge of taking over the commercial and consumer sectors of the lighting industry. With greater efficiency, longer useful lives, and their “clean” nature, LEDs are the future of light, pushing traditional incandescent and fluorescent bulbs toward extinction. Only the higher production costs for LEDs has extended the existence of traditional bulbs.

History

When viewing the history of traditional bulbs, the higher costs associated with producing LEDs is not an insurmountable hurdle to overcome. The fasadskylt incandescent bulb lingered for about 70 years before supplanting “candles, oil lanterns, and gas lamps” as the main source of lighting.[2] When the first crude incandescent bulb was created in 1809 by Humphrey Davy, an English chemist, using two charcoal strips to produce light, it remained impractical. Later when the first true incandescent bulb was created by Warren De la Rue in 1820, utilizing a platinum filament to produce light, it was too expensive for commercial use. Only when Thomas Edison created an incandescent bulb utilizing a carbonized filament within a vacuum in 1879, did the incandescent bulb become practical and affordable for consumer use.

Although considered relatively novel, the concept for LEDs first arose in 1907 when Henry Joseph Round used a piece of Silicone Carbide (SiC) to emit a dim, yellow light. This was followed by experiments conducted by Bernhard Gudden and Robert Wichard Pohl in Germany during the late 1920s, in which they used “phosphor materials made from Zinc Sulphide (ZnS) [treated] with Copper (Cu)” to produce dim light.[3] However, during this time, a major obstacle existed, in that many of these early LEDs could not function efficiently at room temperature. Instead, they needed to be submerged in liquid nitrogen (N) for optimal performance.
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garnerjuriya

Posted:
2019-10-19 09:25

The patient gets the thick end of a poor deal. You are not treated as though it is your body and you often face long waits for treatment. I faced that myself in A & E when I had a problem with my foot. I was told to take my shoe and sock off and to wait in a cubicle on a stool. Getting a bit weary nearly an hour later I inadvertently leant back and set off an alarm. A nurse came in, turned off the alarm, said 'don't do that' and walked out. An hour later I walked out too. https://frenchmart.fr/


garnerjuriya

Posted:
2019-10-19 09:25

The patient gets the thick end of a poor deal. You are not treated as though it is your body and you often face long waits for treatment. I faced that myself in A & E when I had a problem with my foot. I was told to take my shoe and sock off and to wait in a cubicle on a stool. Getting a bit weary nearly an hour later I inadvertently leant back and set off an alarm. A nurse came in, turned off the alarm, said 'don't do that' and walked out. An hour later I walked out too. https://frenchmart.fr/

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