How to separate a mixture of organic acids by HPLC?

I would like to develop a method for analysis of many organic acids in the same time. how to separate the chromatographic pics of each one?

09 September 2020 9,128 6 View

What internal standard can be used for the analysis of amino acids and organic acids by HPLC (wath ever the type of HPLC used)?

I want a list of internal standards can be used if it is possible

06 September 2020 7,224 4 View

Is anyone familiar with the cyclic compressive fatigue testing (BS EN 12697 - 25) ?

I would like to get more information on the cyclic compressive fatigue testing (BS EN 12697 - 25) which is typically done for bituminous material in pavement design. Any one can advise on the...

28 February 2021 2,004 3 View

What could be the reason for not having further low chi square value (better agreement) in my refinement result?

I have tried every combination of parameter changes and after that i have a poor chi square value. I can't get it lower any further. I know there have been a lot of discussion about Rietveld...

26 February 2021 8,480 3 View

Stress/strain tensors decomposition ???

25 February 2021 6,760 1 View

Why the CHi^2 is close to zero with a bad fitting but the Rp and Rwp are still high?

I am refining my XRD data using in FullProf program. The intensity of the modulated X-ray peaks is almost flat. I tried to adjust the peak intensities but unsuccessful. What is the reason? I guess...

23 February 2021 2,304 4 View

The most suitable method to calculate the stress intensity factor in the presence of contact between the crack lips?

I'm trying to study cracked structures under a compressive load taking into account contact between the crack lips. I would like to know if the method of extrapolation by displacement remains...

21 February 2021 8,694 4 View

Why CHi^2 is reducing if I divide the intensity by a constant factor?

I was refining my XRD data in FullProf. Highest intensity was 400000. The fitting was good but still the Chi^2 value is very high (0.174E+04) I divided the intensity by some constant factor (say...

17 February 2021 3,383 5 View

Is it possible to do Reitveld Refinement on single crystal XRD data?

I tried to do single-crystal Rietveld Refinement on my single-crystal XRD data using the option "refinement on single-crystal data/ integrated intensity data" in Fullprof but it is giving error...

30 January 2021 7,813 3 View

How to take into account the high resolution of the x-ray difractometer?

At small angles or in case high collimation, the peaks become anisotropic and with a Lorentz addition. The resolution describes correctly only with adding Lorentz and anisatropy parameters. It...

26 January 2021 5,829 4 View

Any reference to learn numerical methods for Viscoelastic compressible fluids(oil) (CFD)?

I am developing a solver to simulate compression of oil in shock absorber filled with viscoelastic compressible oil. The model will consider the loss due to viscosity which will decide the...

15 January 2021 1,707 1 View

How to implement truss element with no effect of compression in ansys workbench static structural?

I was trying to add ligaments in cervical spine geometry. There it is mentioned in the existing literature to add the ligaments in the geometry as truss element with no effect of compression....

03 January 2021 2,205 0 View