Additional file 1: Figure S2B shows that dimensions of the sample cylinders are just sufficient to ensure pervasive shear failure of the samples, so that boundary effects cannot be ruled out completely.
The oxygen concentrations at sampling angles and the cylinder pressure were measured.
Density of powdered nano SiO2 compound is ρpowder = 0,1 g/cm3 (density in packaging is approximately ~0,3 g/cm3), volume of the sample in cylinder-shaped radiation packaging is Vpowder ≈ 2,3 cm3, the area of the sample which is exposed to neutron flux is Spowder ≈ 10 cm2.
The samples were cylinders with a diameter of 8 mm and a height of 15 mm.
In the friction experiments, all the pre-compacted samples were subjected to an initial slip velocity of 0.28 mm/s until ~170 mm of displacement (three rotations of the sample cylinder), during which time the friction value either increased or decreased to attain a roughly steady-state value.
The sample is manufactured into the cylinder with the diameter and length of 1 cm or less than 1 cm.
The brain tissue sample was placed inside the cylinder symmetrically with respect to the holes and the plungers were placed on either side.
In principle, the piston can be quite long, so a piston-cylinder design can accommodate a much larger volume of sample than the squeezer, depending on the dimensions of the sample-holding cylinder.
The exploration on magnetic shield design shows the discrepancy of shielding performance occurs in the case of the paralleling external magnetic field to the sample cylinder.
