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| - | = Illumination =
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| - | In Strickland's paper, it's mentioned that they used 8000 mcd LEDs from [http://www.theledlight.com theledlight.com], with 20º viewing angle and 468 nm at 3.4 V.
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| - | It's also mentioned that a single LED was used per tube, with a cross section of 0.12 cm<sup>2</sup> = 1.2x10<sup>-5</sup> m<sup>2</sup>.
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| - | 20º viewing angle, 0.35 rad, means a solid angle of 2π(1-cos(0.35)) = 0.381 sr.
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| - | This gives a luminous flux of 0.381*8 = 3.05 lm per LED.
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| - | The illuminance they used was then 3.05/1.2x10<sup>-5</sup> = 2.54x10<sup>5</sup> lux (or lm/ m<sup>2</sup>).
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| - | A bioreactor that has some 0.2*π*0.3 = 0.19 m<sup>2</sup>, we would need at least 2.54x10<sup>5</sup> * 0.19 = 48260 lm, or some 16000 LEDs just to make sure the outer surface of the bioreactor has the same light conditions!!
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| - | This doesn't take into account reflections in the bioreactor, so I hope it will lower this number.
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| - | == Illuminance test ==
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| - | We can try first different illuminance values, to get an idea about the range in which the LovTAP-VP16 switch saturates. This could be done by using cylindrical cell culture test plates (there are two sizes: 8.96 sqcm and 3.60 sqcm of circular base).
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| - | If we take the one with 3.60 sqcm (or 2.14 cm in diameter), considering we have 20º LEDs, the distance between the well bottom and the LED has to be of around 6 cm to have the whole well illuminated.
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| - | But, attention! This will be some 20 times less illuminance than in Strickland's experiment!
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| - | If we take the plates with 24 wells, or 1.86 cm2 the well, or 1.54 cm in diameter: the distance from LED to well bottom should be around 4.4 cm. The height of the plates is 22 mm, perfect!
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| - | The viewing angle of our LEDs is 20º, what means a solid angle of 2 pi (1 - cos(20)) = 0.378 steradians. According to the definition of candela, our 9 cd LEDs should be providing some 40 mW of radiant energy, or 21 mW/cm2 in a 1.86 cm2 well.
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| | == Cell culture absorbance test == | | == Cell culture absorbance test == |
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