Sorption kinetic of water vapour of MX80 bentonite submitted to different physical-chemical and mechanical conditions

Abstract The clay materials are widely used in industrial processes. One significant application is as a solid desiccant agent or as a dehydrator of gases. In this case, it is fundamental to investigate on the sorption kinetics of water vapour. The main aim of the current study has been to present an experimental-theoretical study on the sorption kinetics of water vapour, using as reference material MX80 bentonite. This clay mineral was submitted at different physical, chemical and mechanical conditions. Then 0.5 g of the modified-sample previously dried for 24 h at 110 • C was placed in plastic desiccators (2 l) under isothermal conditions and atmospheric pressure, here the relative humidity was controlled by a supersaturated salt solution. This instrumental system allowed us to study the sorption kinetics of water vapour of MX80 bentonite where the control parameters were the interlayer cation (bentonite exchanged with Na, Li, K, Mg, Ca), mechanical compaction (uni-axial system at 21, 35 and 63 MPa), drying temperature of sample (110, 150, 250 and 500 • C), relative humidity (61, 75, 87 and 95%) and the amount of the sample (0.5, 1, 2, 3, 4 and 5 g). Thanks to a kinetic model of second order it was possible to estimate that the sorption kinetic of water vapour of MX80 bentonite depends directly on the relative humidity, the interlayer cation and amount of the sample. In contrast, the sorption kinetics of water vapour was lightly affected by the mechanical compaction. Finally, the sorption kinetics of water vapour was modified by the drying temperature of sample exclusively when this is very high (for example, 500 • C)

Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

Gluons and the quark sea at high energies: distributions, polarization, tomography

This report is based on a ten-week program on "Gluons and the quark sea at high-energies", which took place at the Institute for Nuclear Theory in Seattle in Fall 2010. The principal aim of the program was to develop and sharpen the science case for an Electron-Ion Collider (EIC), a facility that will be able to collide electrons and positrons with polarized protons and with light to heavy nuclei at high energies, offering unprecedented possibilities for in-depth studies of quantum chromodynamics. This report is organized around four major themes: i) the spin and flavor structure of the proton, ii) three-dimensional structure of nucleons and nuclei in momentum and configuration space, iii) QCD matter in nuclei, and iv) Electroweak physics and the search for physics beyond the Standard Model. Beginning with an executive summary, the report contains tables of key measurements, chapter overviews for each of the major scientific themes, and detailed individual contributions on various aspects of the scientific opportunities presented by an EIC.Comment: 547 pages, A report on the joint BNL/INT/Jlab program on the science case for an Electron-Ion Collider, September 13 to November 19, 2010, Institute for Nuclear Theory, Seattle; v2 with minor changes, matches printed versio

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM