Milling surface plot

Figure 5 An additive model three-dimensional response surface plot for fines from the milling study.

Figure 1 presents the plot of the BET specific surface area vs the irreversible capacity measured for graphite samples milled in different atmospheres and sometimes post-treated by pyrolytic carbon deposition. The experimental values are quite scarce and, contrarily to several claims [7-9], there is not any linear dependence between these two parameters. It seems that the linearity would exist only for samples from the same family with comparable microtextures. 

Perhaps of more general applicability for the study of the properties of positronium is its production by the desorption of surface-trapped positrons and by the interaction of positrons with powder samples. According to equation (1.15) it is energetically feasible for positrons which have diffused to, and become trapped at, the surface of a metal to be thermally desorbed as positronium. The probability that this will occur can be deduced (Lynn, 1980 Mills, 1979) from an Arrhenius plot of the positronium fraction versus the sample temperature, which can approach unity at sufficiently high temperatures. The fraction of thermally desorbed positronium has been found to vary as... 

Volcanic injection of large quantities of sulfate aerosol into the stratosphere offers the opportunity to examine the sensitivity of ozone depletion and species concentrations to a major perturbation in aerosol surface area (Hofmann and Solomon, 1989 Johnston et al., 1992 Prather, 1992 Mills et al., 1993). The increase in stratospheric aerosol surface area resulting from a major volcanic eruption can lead to profound effects on CIO,-induced ozone depletion chemistry. Because the heterogeneous reaction of N2OS and water on the surface of stratospheric aerosols effectively removes NO2 from the active reaction system, less NO2 is available to react with CIO to form the reservoir species CIONO2. As a result, more CIO is present in active CIO, cycles. Therefore an increase in stratospheric aerosol surface area, as from a volcanic eruption, can serve to make the chlorine present more effective at ozone depletion, even if no increases in chlorine are occurring. Figure 4.26 shows in situ stratospheric data (solid circles) on NO / NOy and CIO/Cl, ratios plotted as... 

Plant tissues/residues of wheat Triticum aestivum L. Coker 916 or 983 or Southern States 555 ), rye Secale cereale L. Abruzzi ), crimson clover Trifolium incamatum L. Tibbee ), and/or subterranean clover (T. subterranean L. Mount Barker ) were collected from litter bags half buried (i.e., the lower half of the bag was located within the soil) in the field plots (Blum et al. 1991) or from the soil surface (Blum 1997 Lehman and Blum 1997 Staman et al. 2001), freeze-dried, and stored in the dark at room temperature. The freeze-dried plant tissues/residues were ground just before analysis in a Wiley mill (20,40 or 60 mesh screen) and then extracted and analyzed by several different procedures ... 

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