Fluid activities inclusion

Because of uncertainties of equilibrium constants, ES, pH, temperature, /02 and other parameters (activity coefficient, ionic strength, activity of water, pressure), the estimated values of concentrations may have uncertainties of 1 in logarithmic unit. However, it can be concluded from the thermochemical calculations and fluid inclusion data that the Kuroko ore fluids have the following chemical features. 

Hedenquist, J.W. and Henley, R.W. (1985) The importance of CO2 on freezing point mea.surements of fluid inclusions evidence from active geothermal systems and implications for epithermal ore deposition. Econ. Geol, 50, 1379-1406. 

The model calculated in this manner predicts that two minerals, alunite [KA13(0H)6(S04)2] and anhydrite (CaSC>4), are supersaturated in the fluid at 175 °C, although neither mineral is observed in the district. This result is not surprising, given that the fluid s salinity exceeds the correlation limit for the activity coefficient model (Chapter 8). The observed composition in this case (Table 22.1), furthermore, actually represents the average of fluids from many inclusions and hence a mixture of hydrothermal fluids present over a range of time. As noted in Chapter 6, mixtures of fluids tend to be supersaturated, even if the individual fluids are not. 

Recently, it was demonstrated in a diamond anvil cell that Shewanella oneidensis and Escherichia coli strains remain physiologically and metabol-ically active at pressures of 680 to 16,800 bars for up to 30 h (Sharma et al. 2002). At pressures of 12,000 to 16,000 bars, living bacteria resided in fluid inclusions in Ice VI crystals and continued to be viable when pressure returned to 1 bar. However, only 1% remained alive whether this constitutes viability or survival under pressure is contentious (Couzin 2002). Nevertheless, it demonstrates that pressure may not be much of an impediment for some life forms, and that even the deep ocean of Ganymede might be suitable for life. 

Dolomite precipitation probably took place at relatively low temperatures (<100°C), on the basis of planar crystal fabrics (Sibley Gregg, 1987) and the dominance of monophase aqueous fluid inclusions (Goldstein Reynolds, 1994). Under such conditions, the precipitation of well-ordered dolomite is favoured by high (Mg " " + Fe " )/Ca ratios, low salinities and high carbonate alkalinity in pore fluids (Folk Land, 1975 Machel Mountjoy, 1986). Low salinity reduces ion pairing, and high COf activities facilitate dehydration of Mg " " ions. Dolomite exhibits retrograde solubility. 

Figure 13. Microbial activity and viability in ice-VI at 1.4 GPa. (A) Complete view of the sample chamber with ice-VI phase with bacteria. Clearly visible is the vein-like structure surrounding the ice phase. (B) Close-up view showing the ice-VI crystal boundary surrounded by clusters of bacteria (Shewanella MRl) within organic-rich veins. (C) After approx. 1 hour, textural changes in the ice occur, defined by the formation of organic-rich inclusions within ice crystals. (D) Close-up view of the fluid inclusions containing clusters of motile bacteria. (E) Upon decompression (to <100 MPa), the viable bacteria (dyed with methylene blue) are seen clustered at the diamond surface but are still observed to be motile.

Molecular dynamics and its extension to fluid dynamics were the two main computational efforts, but a new version of IBMOL and of other codes had to be written once more. The IBM postdoctoral program was eventually extended also to Poughkeepsie site and later to the Kingston site, with full industrial IBM efficiency , namely, I had to prepare a yearly detailed research plan with inclusion of both permanent and temporary (the postdoctorals and the visitors) personnel, and since IBM was in a growth period, the expected yearly manpower increase My work was supposed to contribute to IBM understanding of the future needs in the scientific market for computer hardware and software this did imply for me close contacts with IBM Headquarters in White Plains and in Armonk, with Dr. Anderson and his staff, and a very active participation for me and for all my collaborators to many IBM scientific meetings, in USA and abroad, where IBM would announce and market his products. 

Tivey MK, Mills RA, Teagle DAH (1998) Temperature and salinity of fluid inclusions in anhydrite as indicators of seawater entrainment and heating in the TAG active mound. Proc ODP, Sci Results 158 179-190... 

Another example of a geometrical photoisomerization process influenced by CD is the cis-trans photoconversion of cyclooctene in solid P-CD complexes. After prolonged irradiation of the cis-cyclooctene complex, an apparent photostationary state with a trans/cis ratio of 0.47 was detected, which was considerably smaller than that obtained in homogeneous fluid solution (0.96). This result is explained by the reduced rotational mobility of the guest in the inclusion complex. The asymmetric CD environment however, is not able to induce optical activity in the photoproduct, which shows an enantiomeric excess of only 0.24%. In this study, light of 185 nm, also absorbed by the CD, was used [302]. 

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