3,090 research outputs found
Pivotal tricategories and a categorification of inner-product modules
This article investigates duals for bimodule categories over finite tensor
categories. We show that finite bimodule categories form a tricategory and
discuss the dualities in this tricategory using inner homs. We consider
inner-product bimodule categories over pivotal tensor categories with
additional structure on the inner homs. Inner-product module categories are
related to Frobenius algebras and lead to the notion of -Morita equivalence
for pivotal tensor categories. We show that inner-product bimodule categories
form a tricategory with two duality operations and an additional pivotal
structure. This is work is motivated by defects in topological field theories.Comment: 64 pages, comments are welcom
Potential performance for Pb-Pb, p-Pb and p-p collisions in a future circular collider
The hadron collider studied in the Future Circular Collider (FCC) project
could operate with protons and lead ions in similar operation modes as the LHC.
In this paper the potential performances in lead-lead, proton-lead and
proton-proton collisions are investigated. Based on average lattice parameters,
the strengths of intra-beam scattering and radiation damping are evaluated and
their effect on the beam and luminosity evolution is presented. Estimates for
the integrated luminosity per fill and per run are given, depending on the
turnaround time. Moreover, the beam-beam tune shift and bound free pair
production losses in heavy-ion operation are addressed.Comment: Submitted to PRSTA
Beam-beam-induced orbit effects at LHC
For high bunch intensities the long-range beam-beam interactions are strong
enough to provoke effects on the orbit. As a consequence the closed orbit
changes. The closed orbit of an unperturbed machine with respect to a machine
where the beam-beam force becomes more and more important has been studied and
the results are presented in this paper.Comment: 5 pages, contribution to the ICFA Mini-Workshop on Beam-Beam Effects
in Hadron Colliders, CERN, Geneva, Switzerland, 18-22 Mar 201
Proton NMR relaxometry as a useful tool to evaluate swelling processes in peat soils
Dramatic physical and physico-chemical changes in soil properties may arise due to temperature and moisture variations as well as swelling of soil organic matter (SOM) under constant conditions. Soil property variations may influence sorption/desorption and transport processes of environmental contaminants and nutrients in natural-organic-matterrich soils. Notwithstanding the studies reported in literature, a mechanistic model for SOM swelling is unavailable yet. The objective of the present study was the evaluation of the swelling of peat soils, considered as SOM models, by 1H NMR relaxometry and differential scanning calorimetry (DSC). Namely, information on the processes governing physical and physicochemical changes of peat during re-hydration were collected. The basic hypothesis of the present study was that the changes are slow and may affect water state as well as amounts of different water types into the peats. For this reason, such changes can be evidenced through the variations of mobility and thermal behaviour of the involved H2O molecules by using 1H NMR relaxometry and DSC. According to the experimental results, a mechanistic model, describing the fundamental processes of peat swelling, was obtained. Two different peats re-wetted at three temperatures were used. The swelling process was monitored by measuring spin-spin relaxation time (T2) over a hydration time of several months. Moreover, DSC, T1 – T2 and T2 – D correlation measurements were done at the beginning and at the end of the hydration. Supplementary investigations were also done in order to discriminate between the swelling effects and the contributions from soil solution, internal magnetic field gradients and/or soil microorganisms to proton relaxation. All the results revealed peat swelling. It was evidenced by pore size distribution changes, volumetric expansion and redistribution of water, increasing amounts of nonfreezable and loosely bound water, as well as formation of gel phases and reduction of the translational and rotational mobility of H2O molecules. All the findings implied that changes of the physical and physicochemical properties of peats were obtained. In particular, three different processes having activation energies comprised in the interval 5 – 50 kJ mol-1 were revealed. The mechanistic model which was, then, developed included water reorientation in bound water phases, water diffusion into the peat matrix and reorientation of SOM chains as fundamental processes governing SOM swelling. This study is of environmental significance in terms of re-naturation and re-watering of commercially applied peatlands and of sorption/desorption and transport processes of pollutants and nutrients in natural organic matter rich soil
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