Math behind

[Heil Tweetler]

My Fantasy Is A BBQ Party With A Bunch of Short Fat Butt Crossed Eyed Chinese Chicks

Wasnt real at that Chinese BBQ?

 

[DrMisunderstood]

PPFD is irradiance measured in µmol/s/m2

I do not want to be the one to say it. Rather I suggest you look at some research papers for the units on PPFD. Technically there is no right or wrong. Many papers avoid PPF and PPFD and use PAR or just the units.

 

[The Dawg]

Wasnt real at that Chinese BBQ?

Na That's Why He Made A Fool Of Himself Posting A Video Of His Feeble Attempt At Crushing A Mars Led. Cause They Told Him He Didn't Have Enough Class To Attend Said BBQ Party Break It Down Julio And Put Some Liquor In It

 

[nfhiggs]

Is that not what I said?

No, not really. You implied the exact opposite in point of fact. It's the light sellers preaching "Blue/Red" spectrum that continually reference algae charts, not the people suggesting white light is superior.

Who cares what you think, not me. Plant Physiology the most authoritative, comprehensive, and widely used upper-division plant biology textbook. For 22 years

Lincoln Taiz is Professor Emeritus in the Department of MCD Biology at the University of California, Santa Cruz, USA. He is a Fellow of the American Society of Plant Biologists. Dr. Taiz has served as an editor for Plant Physiology, Plant Physiology and Biochemistry, New Phytologist, Botanica Acta, and the Annual Review of Plant Physiology.

Eduardo Zeiger is Professor Emeritus in the Department of Ecology and Evolutionary Biology at the University of California, Los Angeles, USA. Angus Murphy, University of Maryland, USA.

Ian M. Møller is Associate Professor of Molecular Biology and Genetics at Aarhus University, Denmark. He received his Ph.D. in Plant Biochemistry from Imperial College, London, UK. He has worked at Lund University, Sweden and, more recently, at Risø National Laboratory and the Royal Veterinary and Agricultural University in Copenhagen, Denmark. Professor Møller has investigated plant respiration throughout his career. His current interests include turnover of reactive oxygen species and the role of protein oxidation in plant cells.

Angus Murphy has been a Professor and Chair of the Department of Plant Science and Landscape Architecture at the University of Maryland since 2012. He earned his Ph.D. in Biology from the University of California at Santa Cruz in 1996 and moved to Purdue University as an assistant professr in 2001. Dr. Murphy studies ATP-Binding Cassette transporters, the regulation of auxin transport, and the mechanisms by which transport proteins are regulated in plastic plant growth.

Tossing out a bunch of names of professors does not prove anything nor does it impress me...

Apparently you did not read very well it is the action spectrum for photosynthesis and the absorption spectrum of chlorophyll a and b. Not bacteriochlorophyll or phycoerythrobilin

View attachment 3960980

And neither the original (which does not have the descriptive paragraph attached), nor the second chart actually mention it being a chart of Chlorophyll A and B - it merely says it is "intact Chloroplasts".

And apparently you are not aware of the presence of Chlorophyll A and B in Algae? and that it is frequently used as a source for chloroplasts in such experiments?


"Chlorophyll A
Chlorophyll a is found in all organisms that photosynthesize, including algae. The reason that chlorophyll a is essential is because it is able to capture light wavelengths that fall in the spectrum of sunlight. Once captured by chlorophyll a (which is located in an organelle called chloroplast), sunlight combines with water and carbon dioxide to produce energy and glucose molecules used to power the algae cell's function. Chlorophyll a is a green pigment, which is what gives plants and many algae their natural green color."

"Chlorophyll B
Chlorophyll b is a green chlorophyll pigment found in plants and green algae. Chlorophyll b augments chlorophyll a's ability to capture sunlight. Green algae is a broad, informal classification of organisms that includes both Kingdom Monera (single-celled organisms that do not have a nucleus) and Kingdom Protista (more complex single-celled organisms that do have a nucleus). Green algae are the most common organism found in fresh water and the ocean, and they are a major supplier of oxygen, which is produced during photosynthesis."

Your chart does NOT give the source of the Chlorophyll A and B, nor does it describe any of the methodology for determining the action spectrum.

http://photobiology.info/Gorton.html - goes into a lot of the methodology, and why you should use absorptance rather than absorbance.

And then there's this paper which shows green photons to be a more efficient driver of photosynthesis than red photons under strong white light (over 400 PPFD)...

And what about the spectral reflectivity profile of the MJ leaf I posted in another thread?

Go ahead and throw away those green and yellow photons if you want, but I'll keep my white light, thank you.

 

[Heil Tweetler]

Na That's Why He Made A Fool Of Himself Posting A Video Of His Feeble Attempt At Crushing A Mars Led. Cause They Told Him He Didn't Have Enough Class To Attend Said BBQ Party Break It Down Julio And Put Some Liquor In It

Real is legit in my view. He helped me build my first light no questions asked.

If you're a mars guy, i got a vintage 900 that works pretty good, goes off like a sparkler from time to time but it grows bud.

 

[The Dawg]

Real is legit in my view. He helped me build my first light no questions asked.

If you're a mars guy, i got a vintage 900 that works pretty good, goes off like a sparkler from time to time but it grows bud.

 

[nfhiggs]

Whatever. I have no time for this nonsense. Good luck with your wimpy ass photons. You are so much smarter than the authors. Yeah right. Where do you get this information? That was rhetorical. And saw the link to the book's website? Bub bye.

LOL....

Yeah, lets not actually examine the info and think about how narrowly you're looking at this. "It's THE book, dammit!" is the sum total of your position.

Its been fun, but clearly you are not willing to actually have a conversation with someone not awed by your genius.

 

[NoFucks2Give]

Its been fun, but clearly you are not willing to actually have a conversation

It's fuckin 1am, hump nite, I am parting my ass off. I really do not have time now. Fuck, get a life.

 

[Rocket Soul]

@moderators: riu led section desperately needs a stickied "watch out for me at the cup/cyberbrawling/led vs hps and any other contentious trolling subjects" thread where people can be referred to take their arguing when they go of subject. And if possible, instead of closing peoples threads or accounts if they are abusive or wont stay on thread subjects just have them banned to the troll thread so they can only post there for a few months.

 

[Abiqua]

Real is legit in my view. He helped me build my first light no questions asked.

If you're a mars guy, i got a vintage 900 that works pretty good, goes off like a sparkler from time to time but it grows bud.

cocaine is a helluva drug....

 

[wietefras]

I do not want to be the one to say it. Rather I suggest you look at some research papers for the units on PPFD. Technically there is no right or wrong. Many papers avoid PPF and PPFD and use PAR or just the units.

Show me a calculation in a research paper where no symbols are used at all and they just say "PAR" or "µMoles".

If they would a term PAR in a descriptive text, then it would be made absolutely clear from the context if it's referring to PPF, PPFD or flux or whatever.

Either way, the real issue here that his use of units and symbols is a complete mess. He says lumens when he means lux and he compares that to "µMoles", which in comparison to lumen would be PPF, but it should have been PPFD. He then even goes so far that he thinks you cannot convert from lumen to PPF because one is irradiance and the other radiance. Not only is it a mess, but he clearly doesn't understand the distinction.

So as a start he should learn which is which. The only way to do that is to make sure he always uses the correct units and symbols.

 

[sethimus]

Apparently you did not read very well it is the action spectrum for photosynthesis and the absorption spectrum of chlorophyll a and b. Not bacteriochlorophyll or phycoerythrobilin

View attachment 3960980

[ ] you did understand the McCree curve in the first place
[x] just give up already

 

[NoFucks2Give]

you did understand the McCree curve in the first place

Don't really need to. All I have to do is look at the results from the experiments.

 

[Photon Flinger]

Is that not what I said?


Who cares what you think, not me. Plant Physiology the most authoritative, comprehensive, and widely used upper-division plant biology textbook. For 22 years

......



Apparently you did not read very well it is the action spectrum for photosynthesis and the absorption spectrum of chlorophyll a and b. Not bacteriochlorophyll or phycoerythrobilin

View attachment 3960980

Don't bother, most of these folks aren't book smart. Come to think of it, they also aren't fans of universities, researchers or anyone who knows how to grow better than them.

Only thing they value are youtube videos of badly grown plants because they don't know any better. If only there was the equivalent of the SPCA for plants we could save those poor defenseless plants from such abuse.

 

[SteelyX]

Goniophotometer is used to measure light distribution by a single luminary. Once you have the data it is compiled into an .IES format that most lighting software uses to calculate light distribution in a facility/building.... I have a radiospectrometer and thus far the Goniophotometer measurements are spot on. This is a simulation of the HLG-550 pro.... When I do the simulation and also measure the same place under the fixture in real time the simulation is within 1-2% which is about as good as it gets.

I can get ppfd numbers anywhere on this simulation. Just point and click. View attachment 3958951

I can't believe Dialux is free. Thanks for the heads up.

The learning curve for Dialux is pretty steep. I don't need to learn how to use every feature, just the light distribution modelling. Is there a quick way to learn to generate the renderings you made? Is making the script available a possibility?

 

[tazztone]

i searched this thread for YPF, but found nothing. (how) can it be calculated?
also the original post looks way to complicated for me

 

[Stephenj37826]

I can't believe Dialux is free. Thanks for the heads up.

The learning curve for Dialux is pretty steep. I don't need to learn how to use every feature, just the light distribution modelling. Is there a quick way to learn to generate the renderings you made? Is making the script available a possibility?

Not really .. The lighting show up in Chicago next month has a dialux class. I'll be there. Probably won't attend the class though. I still don't know all that dialux has to offer.... It is great though.

 

[wietefras]

i searched this thread for YPF, but found nothing. (how) can it be calculated?
also the original post looks way to complicated for me

You take the McCree curve and correct the numbers for that, much like the original calculation converts from lumen to SPD curves

 

[dzigi24]

With LER we can convert lumens into watts, calculate efficiency of a light source and how much heat it produces. Watt, however, is not a preferred botanical unit. Micromole of photons (in the 400nm to 700nm range) [µmol] is. To be able to convert radiant power into number of photons we’ll have to calculate quantum efficacy of radiation (QER) for our spectra. This quantity tells us how many photons a spectrum produces per radiated energy. The process is quite similar to LER calculation.

Let’s call SPD function J(λ). There will also be some constants:

Planck constant; h = 6.62606957 × 10^-34 J*s
Avogadro constant; NA = 6.0221413 × 10^23 mol-1
Speed of light; c = 299792458 m/s

For each wavelength, energy per mole of photons can be calculated as:
View attachment 3405776
Then:
View attachment 3405777

or if we’re to use 400-700nm range, the equation would change to:
View attachment 3405778

Constants are pretty clear I guess. Then QER is simply ratio of area under the SPD/Energy per mole graph and the SPD graph.

Again Excel will help us. Using the same sheet, we’ve already have 4 columns filled. Now we can add constants somewhere so we can use them later. Column E is to be filled with SPD/energy per mole ((h*c*Na)/λ).

NOTE since wavelength is in nanometers and we’d like to have our final results in micromoles, the equation is changed to (h*c*Na)/(λ*10^-3). It’s for the sake of correct decimal point.

Then QER is simply:
QER = sum(E:E) / sum(B:B)
View attachment 3405779

Zipped Excel book with all the equations is attached.

Please can you help me and calculate for me I didnt understand this :/

 

[sethimus]

any math guru here that could help me deconstruct the (quite) similar spectrums of fluence and gavita?

fluence looks like they use a 3500k base + 660nm (haven't found a clear picture of the spydr 2 where you can count the diodes yet), gavita uses 4000k + 660nm (408 lm301b + 8 osram 660nm per bar), what i want to know how much percent the additional 660nm part of both spectrums is:

currently i'm planning with a hlg 480 + 8 f-series FB24 bars, and i want to add 6 led-tech 50cm osram 660nm stripes (10 leds each), i just don't know what kind of driver i should choose for the 660nm channel. 80W, 100W or 120W?

help a brother out please