Developing the NIS solid density hydrostatic weighing system up to 20 kg Mohamed Hamdy, Mohamed A. Bayoumi, Ali E. Abuelezz and Alaaeldin A. Eltawil Int. J. Metrol. Qual. Eng., 11 (2020) 8 Published online: 15 October 2020 DOI: 10.1051/ijmqe/2020006