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Questions related from M. Farooq Wahab
Grotrian diagrams often taught in instrumental methods of chemical analysis to chemists. After a decade, I finally found the original book of 1927 by Grotrian "Graphische Darstellung der Spektren...
02 February 2019 741 9 View
I am thinking of a hypothetical scenario, when we do not have the original time and signal but rather the FT of it i.e. the amplitude vs. frequency axis is known to us. We know the frequency...
03 March 2017 9,642 3 View
Imagine if we have a suspension of poly-disperse rigid spherical particles (~ 5 micron, 10-30 % RSD) which are being pressure filtered into narrow tubes. Ideally one should have random...
05 May 2015 8,963 11 View
If we are interested in sampling a Gaussian peak, it is said that the critical sampling frequency should at least be 2x maximum frequency present in a signal. If we look at the attached analysis...
04 April 2015 1,866 10 View
It is often observed that silica suspensions can be relatively stable in purely non-aqueous organic solvents. Apparently there are no electrolytes or free ions/ counter-ion in the organic solvent,...
02 February 2015 2,452 18 View
Spherical particles of silica and other materials are tightly packed at very high pressures (>10,000 psi) into narrow columns (< 5 mm i.d.) for separating mixtures. The smaller the width of...
02 February 2015 2,818 11 View
I am looking for a mathematical relation between data collection rate (sampling frequency) and detector noise. In general the noise increases when sampling frequency is increased. This is with...
01 January 2015 1,582 17 View
Is there a simple way to predict turbulence in a dilute suspension of spherical particles (say ~ 10% w/v) which are travelling in a tube under very high pressures (> 8000 psi) but low flow...
12 December 2014 7,668 7 View
Generally, it is said that when dispersed suspensions of small particles (~ 5 micron spheres) are pressure filtered in narrow columns, the particles travel individually and form a random closed...
12 December 2014 4,947 4 View
Hello, Is it possible that slurry packing methods which work very well with analytical size 4.6 mm i.d. tube tend to give much lower performance in terms of chromatographic efficiency with...
12 December 2014 3,345 4 View
This question is related to suspension rheology. Is anyone familiar with some qualitative tests which allow us to predict whether a given suspension will be shear thickening or shear thinning...
11 November 2014 9,247 16 View
Does anyone know if we pack a bed of spheres in a tube, why does the radial porosity profile oscillate near the tube walls and finally becomes a straight line as we move into the bulk? It seems...
11 November 2014 923 21 View
We recently had an excellent discussion on the sign of the electrode potential of half...
10 October 2014 5,034 3 View
Dear readers, I am doing a short academic survey on some concepts in electrochemistry for educational purposes. The question is simple: What do you understand by the negative and positive signs...
10 October 2014 9,542 34 View
I have a phosphonium based zwitterion which has a carboxylic acid and a sulfonate group. The sulfonate exists as potassium salt (or the molecule has potassium as a counter ion). I tried standard...
09 September 2014 1,542 13 View
The concept of relative atomic weight originated from measuring the combining weight of hydrogen with a certain element. In the simplification process H was taken as unity (18th, 19th and 20th...
01 January 1970 8,648 10 View
