Global challenges of capturing carbon dioxide

Within this general context, this talk will consider the use of novel nanoporous materials as the basis for adsorption based separations [3] that will range from concentrated mixtures to direct capture of carbon dioxide from air. An overview of different classes of materials will show how these can be tailored to such a wide range of conditions. The sheer scale of the task leads to having to optimize systems and speed up processes, which in turn brings in diffusion limitations

Heavy Quark Correlations in Photon-Hadron Collisions

We describe a next-to-leading-order calculation of the fully exclusive parton cross section for the photoproduction of heavy quarks. We use our result to compute quantities of interest for current fixed-target experiments. We discuss heavy-quark total cross sections, distributions and correlations.Comment: 34 pages (LaTex) + 15 figures (topdrawer, included at the end) CERN-TH 6921/93, GEF-TH-15/199

Decaying Leptophilic Dark Matter at IceCube

We present a novel interpretation of IceCube high energy neutrino events (with energy larger than 60 TeV) in terms of an extraterrestrial flux due to two different contributions: a flux originated by known astrophysical sources and dominating IceCube observations up to few hundreds TeV, and a new flux component where the most energetic neutrinos come from the leptophilic three-body decays of dark matter particles with a mass of few PeV. Differently from other approaches, we provide two examples of elementary particle models that do not require extremely tiny coupling constants. We find the compatibility of the theoretical predictions with the IceCube results when the astrophysical flux has a cutoff of the order of 100 TeV (broken power law). In this case the most energetic part of the spectrum (PeV neutrinos) is due to an extra component such as the decay of a very massive dark matter component. Due to the low statistics at our disposal we have considered for simplicity the equivalence between deposited and neutrino energy, however such approximation does not affect dramatically the qualitative results. Of course, a purely astrophysical origin of the neutrino flux (no cutoff in energy below the PeV scale - unbroken power law) is still allowed. If future data will confirm the presence of a sharp cutoff above few PeV this would be in favor of a dark matter interpretation.Comment: 19 pages, 3 figures. Version published in JCAP. The analysis was performed in terms of the number of neutrino events instead of the neutrino flux, using a multi-Poisson likelihood approac

Accelerated degradation of MOFs under flue gas conditions

The zero length column (ZLC) technique is used to investigate the stability of Mg- and Ni-CPO-27 metal organic framework (MOF) crystals to the presence of water and humid flue gas. The design of the ZLC enables the stability test to be conducted over a considerably shorter time period and with lower gas consumption than other conventional techniques. A key advantage over other experimental methods to test the stability of adsorbents is the fact that the ZLC allows to quantify the amount adsorbed of every component present in the gas mixture. The developed protocol is based on a two-stage stability test. The samples were first exposed to a humid carbon dioxide and helium mixture in order to study the effect of water on the carbon dioxide adsorption capacity of the samples. In the second stage the samples were exposed to a flue gas mixture containing water. From the preliminary water stability test, the Ni-sample exhibited the highest tolerance to the presence of water, retaining approximately 85% of its pristine CO2 capacity. The Mg-MOFs deactivated rapidly in the presence of water. The Ni-CPO-27 was then selected for the second stage of the protocol in which the material was exposed to the wet flue gas. The sample showed an initial drop in the CO2 capacity after the first exposure to the wet flue gas followed by a stabilisation of the performance over several cycles.PostprintPeer reviewe

Improving the Weizs\"acker-Williams Approximation in Electron-Proton Collisions

We critically examine the validity of the Weizs\"acker-Williams approximation in electron-hadron collisions. We show that in its commonly used form it can lead to large errors, and we show how to improve it in order to get accurate results. In particular, we present an improved form that is valid beyond the leading logarithmic approximation in the case when a small-angle cut is applied to the scattered electron. Furthermore we include comparisons of the approximate expressions with the exact electroproduction calculation in the case of heavy-quark production.Comment: 10 pages (LaTex, style file included) + 3 table