An advantage of using chlorofluorocarbons (CFCs) and sulfur hexafluoride (SF6) as tracers of ocean circulation is that the time-dependent source functions permit calculation of rates for ocean processes. These compounds are also sensitive indicators highlighting interior ocean regions where surface-derived anomalies can be transported on timescales of decades. Significant applications for CFCs ...

The distribution of gases such as ozone and water vapour in the stratosphere - which affect surface climate - is influenced by the meridional overturning of mass in the stratosphere, the Brewer-Dobson circulation. However, observation-based estimates of its global strength are difficult to obtain. Here we present two calculations of the mean strength of the meridional overturning of the stratos...

This paper provides an overview of materials’ performance in well environments containing H2S and elemental sulphur (S). Based on this information the factors affecting the service life of materials used for well completion and surface facilities in highly sour environments are discussed and limitations on materials selection and chemical inhibition procedures are suggested.

The stability of the optical electric field sensor (OEFS) in actual operation is affected by environmental factors such as temperature and SF6 (sulfur hexafluoride). To analyze the operational environment parameters affecting the optical properties of crystals, a thermodynamic model of the OEFS in which the optical properties of the crystal are changed by the first-order effects and the second-...

Gas-phase reactions of singly-charged anions with multiply-protonated peptides, in a RF quadrupole linear ion trap, leads to either peptide deprotonation (proton transfer) or electron deposition (electron transfer). The former process induces peptide backbone cleavage through a reaction scheme analogous to electron capture dissociation (ECD). Here we characterize the preferred reaction pathways...

During single-breath washouts in normal gravity (1 G), the phase III slope of sulfur hexafluoride (SF6) is steeper than that of helium (He). Two mechanisms can account for this: 1) the higher diffusivity of He enhances its homogeneous distribution; and 2) the lower diffusivity of SF6 results in a more peripheral location of the diffusion front, where airway asymmetry is larger. These mechanisms...

We report calculated cross sections for elastic and electronically inelastic collisions of low-energy electrons with sulfur hexafluoride, SF6 . Elastic cross sections are computed within the fixed-nuclei approximation, with polarization effects incorporated. Inelastic cross sections for nine low-lying states are computed in a few-channel approximation. We compare our cross sections to previous ...

Commercially available equipment for automatic gas-sampling is both expensive and bulky. Air infiltration into refrigerated areas should ideally be measured with low-cost, portable, automatic gas-samplers, capable ofoperating in a wide range of ambient temperatures. This paper describes such a sampler. Although the need for portability limits the size ofthe equipment and therefore the volume of...