Shock effects experiments on serpentine and thermal metamorphic conditions in Antarctic carbonaceous chondrite

The unique Antarctic carbonaceous chondrites, Belgica (B)-7904,Yamato (Y)-86720,Y-82162,Y-793321 are thermally metamorphosed. However, the heat source of the thermal metamorphism is not known. Two strong possibilities are shock-induced heating and heating on the parent body. The explosive impact method was used to check the possibility of heating of phyllosilicates by shock compression. Examining the shocked specimens from the Murchison meteorite and terrestrial lizardite, the following were found : (1) Phyllosilicates in the shocked (>32.1GPa) specimens changed to nearly amorphous substances; (2) the phyllosilicates in specimens shocked at lower pressures were still crystalline and undamaged; (3) some void-like (bubble) textures were widely observed in the amorphous substances; (4) the other minerals such as pyroxenes and olivines which did not change to glass phases seem to be little affected by shock. These facts do not suggest that the unique Antarctic chondrites experienced significant shock

High Pressure Phases found in Yamato 790729.

第2回極域科学シンポジウム/第34回南極隕石シンポジウム 11月17日（木） 国立国語研究所 2階講

Shock wave equation of state of muscovite

Shock wave data to provide an equation of state of muscovite (initial density: 2.835 g/cm^3) were determined up to a pressure of 141 GPa. The shock velocity (Us) versus particle velocity (Up) data are fit with a single linear relationship: U_s=4.62(±0.12) +1.27(±0.04)U_p (km/s). Third-order Birch-Murnaghan equation of state parameters (isentropic bulk modulus and isentropic pressure derivative of bulk modulus) are K_(os)=52±4GPa and K'_(os)=3.2±0.3. The pressure-temperature relation along the Hugoniot suggests that muscovite may dehydrate to KAlSi_3O_8 (hollandite), corundum, and water, with a small volume change, above 80 GPa. Thermodynamic calculations of the equilibrium pressure for the dehydration yields a significantly lower value. Observed unloading paths from shock pressures up to about 80 GPa are steeper in a density-pressure plane than the Hugoniot and become shallower with increasing shock pressure above that pressure. The changing slope may indicate that devolatilization occurs during unloading above 80 GPa. The present equation of state data for muscovite are compared with results of previously reported recovery experiments

Pneumatosis intestinalis leading to perioperative hypovolemic shock: Case report

Pneumatosis intestinalis (PI) is an uncommon disorder defined as multiple foci of gas within the intestinal wall. Despite recognition of an increasing number of cases of PI, the optimal management strategy, whether through surgical or other means, remains controversial. The present report describes the case of a patient with PI who underwent exploratory laparotomy without specific findings and who ultimately died due to extensive intestinal hemorrhage that was possibly triggered by surgery