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Arakawa, Masahiko*; Yasui, Minami
Physics and Chemistry of Ice 2010, p.339 - 344, 2011/05
We conducted impact experiments of water ice and measured a post shock temperature of impact crater using an infrared video camera. The surface temperature in a crater showed a peak temperature just after the impact then it cooled down gradually with time. The decay time of maximum temperature might depend on a scale of heated volume in a crater, so we estimated the ratio of thermal energy to projectile kinetic energy. As a result, we found that up to 10% of the projectile kinetic energy was partitioned into the post shock heating of the impact crater.
Shimaki, Yuri*; Arakawa, Masahiko*; Yasui, Minami
Physics and Chemistry of Ice 2010, p.379 - 386, 2011/05
Impact disruption of sintered snowballs was studied to clarify the effect of sintering on impact strength and fragment velocity. Ice and snow projectiles were impacted on sintered snowballs with a porosity of 40%. The sintering duration of snow was changed from 1 hour to 1 month, and the effect of sintering on impact strength and static strength were examined. As a result, it was found that both impact strength and static strength of snow have a power law relationship to a sintering duration with a power law index of about 0.2.
Yasui, Minami; Arakawa, Masahiko*
Physics and Chemistry of Ice 2010, p.387 - 395, 2011/05
We did deformation experiments on ice-silica mixtures to study their flow laws. We found that the mixture became softer as porosity or silica mass content increased. A power law index 
and an activation energy 
were found to depend only on silica mass content.