search for: spectrophotometer

Dear R-list, It is not uncommon for laboratory equipment (e.g. spectrophotometers) to have a linear response in a certain interval and then go into saturation. I wonder if there is an R-function that models this; for instance by estimating the breakpoint and fitting a line below the breakpoint and a constant above. Best regards Thomas Poulsen -- Thomas Poulsen Research...

Dear friends, Hope you are all doing well and having a great weekend. I have data that was collected on specific gravity and spectrophotometer analysis for 26 mixtures of NG (nitroglycerine), TA (triacetin), and 2 NDPA (2 - nitrodiphenylamine). In the dataset, x1 = %NG, x2 = %TA, and x3 = %2 NDPA. The response variable is the specific gravity, and the rest of the variables are the predictors. This is the dataset: dput(mod14data_random...

Hi, I wonder if anyone could advise me with this: I've been trying to make a standard curve in R with lm() of some standards from a spectrophotometer, so as I can express the curve as a formula, and so obtain values from my treated samples by plugging in readings into the formula, instead of trying to judge things by eye, with a curve drawn by hand. It is a curve and so I used the following formula: model <- lm(Approximate.Counts~X..Ligh...

...8.809e-05 91.03 2.664e-24 1.497e-08 > 10.81 > > J Nash > > > On 2023-08-19 16:19, Paul Bernal wrote: > > Dear friends, > > > > Hope you are all doing well and having a great weekend. I have data that > > was collected on specific gravity and spectrophotometer analysis for 26 > > mixtures of NG (nitroglycerine), TA (triacetin), and 2 NDPA (2 - > > nitrodiphenylamine). > > > > In the dataset, x1 = %NG, x2 = %TA, and x3 = %2 NDPA. > > > > The response variable is the specific gravity, and the rest of the > > varia...

...er control 0.5 + 0.5mg / L of malate T + 1 dechlorinated water control + 1g / L of malate T ED dechlorinated water control SED + ER + river water sediment SED ED + sediment + water dechlorinated. It is the result of AChE in muscle (fillet of fish). The production of acetylcholine is followed with a spectrophotometer every 15 seconds for two minutes. The results are presented in the following table: traitement t15 t30 t45 t60 t75 t90 t105 t120 ER 0.100 0.110 0.123 0.135 0.147 0.159 0.171 0.182 ER 0.112 0.134 0.153 0.174 0.192 0.208 0.226 0.251 T+0.5 0.078 0.082 0.088 0.094 0.101 0.108 0.113 0.120 t+0.5 0.053...

...64e-24? ?1.497e-08? ? ? ?10.81 > > J Nash > > > On 2023-08-19 16:19, Paul Bernal wrote: > > Dear friends, > > > > Hope you are all doing well and having a great weekend.? I have data that > > was collected on specific gravity and spectrophotometer analysis for 26 > > mixtures of NG (nitroglycerine), TA (triacetin), and 2 NDPA (2 - > > nitrodiphenylamine). > > > > In the dataset, x1 = %NG,? x2 = %TA, and x3 = %2 NDPA. > > > > The response variable is the specific gravity, and t...