55 research outputs found
Charge Form Factor and Cluster Structure of Li Nucleus
The charge form factor of Li nucleus is considered on the basis of its
cluster structure. The charge density of Li is presented as a
superposition of two terms. One of them is a folded density and the second one
is a sum of He and the deuteron densities. Using the available
experimental data for He and deuteron charge form factors, a good
agreement of the calculations within the suggested scheme is obtained with the
experimental data for the charge form factor of Li, including those in
the region of large transferred momenta.Comment: 12 pages 5 figure
CO2 wettability of seal and reservoir rocks and the implications for carbon geo-sequestration
We review the literature data published on the topic of CO2 wettability of storage and seal rocks. We first introduce the concept of wettability and explain why it is important in the context of carbon geo-sequestration (CGS) projects, and review how it is measured. This is done to raise awareness of this parameter in the CGS community, which, as we show later on in this text, may have a dramatic impact on structural and residual trapping of CO2. These two trapping mechanisms would be severely and negatively affected in case of CO2-wet storage and/or seal rock. Overall, at the current state of the art, a substantial amount of work has been completed, and we find that: 1. Sandstone and limestone, plus pure minerals such as quartz, calcite, feldspar, and mica are strongly water wet in a CO2-water system. 2. Oil-wet limestone, oil-wet quartz, or coal is intermediate wet or CO2 wet in a CO2-water system. 3. The contact angle alone is insufficient for predicting capillary pressures in reservoir or seal rocks. 4. The current contact angle data have a large uncertainty. 5. Solid theoretical understanding on a molecular level of rock-CO2-brine interactions is currently limited. 6. In an ideal scenario, all seal and storage rocks in CGS formations are tested for their CO2 wettability. 7. Achieving representative subsurface conditions (especially in terms of the rock surface) in the laboratory is of key importance but also very challenging
Time evolution of the X-ray emission from a micropinch in a vacuum spark discharge
The spectrum of the soft-X-ray emission of a Mg- micropinch plasma in a vacuum spark device has been recorded as a function of time, by employing a streak camera. The emission from the He-like ions occurs in two bursts - a very intense one of 200 ps duration and a second one of lower intensity but with a duration of 400 ps. The observations support the radiative-collapse model as explanation of the micropinching process and of the formation of the tiny hot plasmas of subnanosecond lifetimes
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