My tube shatters when immersedunder liquid nitrogen, what should I do?
This is mainly caused by mechanical stress that isgenerated bythe large temperature gradient (77 K on the bottom and 300 K on the top) over the tube. Our suggested solutions, which are based on the physical property of differentmaterials and stress equations, are as follows: (1) Increasing the wall thickness. Bychanging from thin-walled tubetomedium-walled tube , the chance of breakage is reduced by a factor of 4; (2) Freezing your sample with pre-cooled isopentane* (2-methylbutane) at around 120K. It will reduce the chance of breakage by a factor of 2; (3) Using quartz tube instead of Pyrex or N51A glass tube with the same wall thickness. This will reduce the chance of breakage by a factor of 14. Due to the sample weight increase, please take extra caution when handling sample tubes withO.D. over 5 mm.Keep the motion of the tube in one direction. Do not suddenly flip or rotate the tube against gravity to avoid sheering force. The most economic solution that we suggest would be the com
