| Author | Comment | Last activity | Moderation | ||
|---|---|---|---|---|---|
| warren | "@wattminder - have you seen some of the recent work with the Riffle, for conductivity monitoring of water? http://publiclab.org/wiki/riffle Also f..." | Read more » | almost 10 years ago | |||
| homechemist | "Well , petroleum ether is a very common chemical is it use for dissolving paintings and for cleaning painting brushes, I am thinking that is possib..." | Read more » | over 10 years ago | |||
| warren | "Wow... where do you get petroleum ether? I'm very interested in the isolation technique... is it applicable to other sample preparation, like for d..." | Read more » | over 10 years ago | |||
| homechemist | "Thank you very much , at first I have to said that this project wouldn’t be possible without your collaboration (Public Lab) And yes , at first yo..." | Read more » | over 10 years ago | |||
| warren | "Hi, Miguel - excellent and exciting to see your work! What kind of non polar solvent did you use? That's like, some kind of oily substance? " | Read more » | over 10 years ago | |||
| warren | "I ended up trying some semi-opaque plastic but indeed the light has to be really strong as a result: http://publiclab.org/notes/warren/07-31-2013/m..." | Read more » | over 10 years ago | |||
| philippg | "@warren: as sensitivity is my main concern, i'd really avoid masking even more intensity. i'm currently experimenting a bit with possible diffusors..." | Read more » | almost 11 years ago | |||
| warren | "Instead of a calibrated light source, what about scanning a sample and non-sample simultaneously, so that you can actually measure the input light ..." | Read more » | almost 11 years ago | |||
| philippg | "@straylight: 'How much water depth (or column depth) is typically analysed when looking for the chlorophyll-A using absorbance ? Is it in the order..." | Read more » | almost 11 years ago | |||
| webbhm | "I volunteer with LMVP (Lakes of Missouri Volunteer Program), and they conduct water quality monitoring. Their algae sampling is quite formal, wher..." | Read more » | almost 11 years ago | |||
| straylight | "wow, what a great sounding project Philipp. I like your thinking. Taking an average over 10 or more rows of the camera image is really good. The i..." | Read more » | almost 11 years ago | |||
| eustatic | "this is cool. I'm in the Gulf Coast of the United States. We have a large algal bloom that happens every year, as well as a lot of nitrate waste ..." | Read more » | almost 11 years ago | |||
| philippg | "hey wattminder, what kind of contaminants can be expected? if they have a specific optical signature, then they can be detected with optical spect..." | Read more » | almost 11 years ago | |||
| wattminder | "Hi Philip, This is very interesting and timely. California is now experiencing a huge boom in Hydraulic Fracturing, a practice that employs water a..." | Read more » | almost 11 years ago | |||
| cfastie | "Excel allows nesting if statements, so: if((if(red>green,red,green))>blue,(if(red>green,red,green)),blue) should work, if you're not int..." | Read more » | about 11 years ago | |||
| cfastie | "=max(blue:red) is soo much easier. Thanks. The greater of three method seems to be useful for transmission or absorption spectra when a continuous..." | Read more » | about 11 years ago | |||
| cfastie | "Dan, you are correct that all we want to know is how the light intensity varies across the sensor where the grating has spread out the spectrum. Un..." | Read more » | about 11 years ago | |||
| warren | "The Bayer filter is frustrating, but if we can figure it out, it might be a hidden plus for us; in some ways, the R, G, and B channels can be treat..." | Read more » | about 11 years ago | |||
| danbeavers | "Perhaps I missed the explination but please help me understand why you don't just sum the 3 bands. It seems to me that the operative filter is the ..." | Read more » | about 11 years ago | |||
| Tom_H | "I think the essence here is that you have to watch carefully what is going on and choose a method that seems most appropriate for the situation. Th..." | Read more » | about 11 years ago | |||
| Tom_H | "Blown out data should show up as 255 in the csv file and thus would appear in a graph as peaks with a flat top (plateau) when graphed in excel, and..." | Read more » | about 11 years ago | |||
| Tom_H | "A simpler formula is: =max(red:blue) " | Read more » | about 11 years ago | |||
| cfastie | "Tom, I'm glad you asked. The proper Excel expression for choosing the greatest among three values did not come to me quickly, so I just used the eq..." | Read more » | about 11 years ago | |||
| Tom_H | "Hi Chris, How did you pick the color channel with the highest value? Did you write an expression for Excel to pick the highest value and use that? ..." | Read more » | about 11 years ago |