@acer thank you so much for the clear and straightforward example. I really appreciate your time and help.

@rlopez thank you for the link, I certainly will study its contents.

@Carl Love and all other repliers, thank you for so much good information! You are all excellent teachers.

@Carl Love thank you for your time and effort. Your solution is straightforward, but unfortunately does not seem to work in 2-D math. I remember that you favor 1-D but for an apprentice as myself 2-D seems a bit easier.

@jganding thank you for helping me out. This is a quite interesting set of utilities. I appreciate your willingness to share them.

@dharr thank you for your time and willingness to help. It is surprising in how many ways Maple can be of help.

@mmcdara thank you for your help. So, if I understand well, the best solution is to go via a procedure as you demonstrated. There is no predefined function. 

@mmcdara thank you so much. This is much more than expected, and I consider it a nice Xmas present. It is quite obvious I still have to learn a lot. Thank you for your willingness to help so many in Mapleprimes. Happy New year!

@Carl Love thank you for your technique, it is simple and efficient

@acer thank you for this clarification, it is a simple and efficient way of doing.

@Thomas Richard thank you for the additional information. I did look up that page but there it states that plot can be used with useunits, from there my confusion. Thanks again for the help

@Thomas Richard thank you for your swift response, it was highly appreciated and worked like a charm. What is the reason that it didn't work with "plot" are there more plot commands that cannot be used with units? 

@mmcdara Sorry to bother you again but have you been able to find some time to look at your worksheet? I hope you enjoy Maple 2022

@mmcdara different version is probably the cause as I am using 2023. I almost don't dare asking but would be willing to give it a second look after you have access to 2022? Best personal regards and thank for all help, you were a beaken in the dark see.

@mmcdara After taking another look I find following parameters:

C__0:= 10 mg

Q:=0.8 mL/min

V__r:= 24 mL

R:= 289.1 micron

rho:= 1.02 g/cm^3

m__b:= 10 g