They performed some experiments to estimate the Kazni constant for the packed bed of spherical particles.
It is my all-the-time question to put or not to put 'the' in these two places:
1. When we have the structure of: type + noun
2. When we have the structure of: noun + of + noun
Thank you in advance.
'Constant' and 'bed' are ordinary nouns and require an article. The adjectives before the noun don't change this. If the last word, 'particles', was singular, you'd need an article before 'spherical' as well.