1,721,098 research outputs found
QCD+QED lattice calculation of hadronic decay rates
Full text linkIsospin is an almost exact symmetry of strong interactions and the corrections to the isosymmetric limit are, in general, at the percent level. For several hadronic quantities relevant for flavour physics phenomenology, such as pseudoscalar meson masses or the kaon leptonic and semileptonic decay rates, these effects are of the same order of magnitude of the uncertainties quoted in current large-scale QCD simulations on the lattice and cannot be neglected anymore. In this contribution I discuss some recent results for the leptonic decay rates of light pseudoscalar mesons obtained by the Soton-RM123 Collaboration including the leading-order electromagnetic and strong isospin-breaking corrections in first-principles lattice simulations. The adopted strategy is within the reach of the present lattice technologies and it allows to determine electromagnetic corrections to physical observables for which delicate cancellations of infrared divergences occur in the intermediate steps of the calculation. The application of the developed method to the study of heavy-light meson and semileptonic decay rates is currently underway
Leading isospin-breaking effects on the lattice
Full text linkIsospin is an almost exact symmetry of strong interactions and the corrections to the isosymmetric limit are, in general, at the percent level. For several hadronic quantities, such as pseudoscalar meson masses or the kaon leptonic and semileptonic decay rates, these effects are of the same order of magnitude of the errors quoted in nowadays lattice calculations and cannot be neglected any longer. In this contribution I discuss some recent results for the pseudoscalar meson spectrum obtained by the RM123 Collaboration including isospin breaking corrections in first-principles lattice simulations
Design Thermal-Hydraulic Outcome of Experimental Velocity Distributions - RIGEL Upgrade
No full textIn the frame of the IFMIF-CDE, the activity summarised here has been carried out. A thermal-hydraulic design analysis, starting from the results of a Water Eexperiment of High Speed, Free Surface, Plane Jet Along Concave Wall, have been performed. Previous analyses were driven by computed nozzle outlet velocity profiles following a well-known analytic expression. As kind of experimental velocity profiles becomes available, their thermal-hydraulic consequences on the main design parameters have to be compared with their most updated amounts. The present work shows both experimental nozzle-outlet and jet-bulk velocity profiles matching design constraints slightly better than previously assumed nozzle-outlet velocity distribution function
IFMIF Liquid Lithium Target Thermal-Hydraulic Analysis Moving from an Experimental Velocity Distribution
No full textIFMIF liquid Lithium Target Thermal-Hydraulic analysis, anywise performed, needs reliable evaluations, or data, about the nozzle outlet velocity profile.This velocity distribution is the initial condition of the physics of the jet. Its evolution meets the power deposition within the jet, driving this way the thermal-hydraulics of the subsystem.Fine evaluations of the nozzle outlet velocity distribution are therefore of basic importance for giving right count of every thermal-hydraulic phenomenon of the IFMIF liquid lithium jet.In absence of better evaluations ENEA analyses were based on the assumption of a calculated fully developed Prandtl-Nikuradse profile.The RIGEL code, was designed by ENEA as a problem oriented calculation tool. It includes a subroutine for building up the jet inlet section velocity profile. This routine can deal with any other velocity profile as well. Of course the code needs nothing but a single vector to be built or read: the velocity distribution. It is then quite simple to arrange in order to have the code reading whatever data as input.A recent work on IFMIF at JAERI measured exactly a nozzle outlet velocity profile and its evolution. These measures were performed in a water jet in kind of hydrodynamic similarity conditions with respect to the design flowing conditions of the IFMIF liquid lithium jet.Aim of the work to be presented is to investigate and discuss the effect of any JAERI measured velocity profile over the IFMIF liquid lithium jet critical parameters.The analysis will be centred about the question whether the variations introduced are to be considered acceptable or not
A Transport Theory Development on the Theory of the Value
No full textThis work justifies and employs the techniques of Transport Theory for the deeper understanding of the economical problem arisen in the line first developed by Piero Sraffa in the framework of the theory of value and distribution. An integral equation is here proposed for making the model more suitable. This integral equation has been moreover solved both using the Liouville–Neumann series and the Separable Kernel approach. From the solutions obtained, it is possible to calculate the value as a function of the methods of production, the wage, and the rate of profits and to discuss the question of the value of the commodities and the proportions of labor to means of productions. © 2016 Taylor & Francis Group, LLC
The need for a taphonomic perspective in spatial analysis: Formation processes at the Early Pleistocene site of Pirro Nord (P13), Apricena, Italy
No full textEver since their percolation from neighbour disciplines, archaeology has employed spatial statistics to unravel, at different scales, past human behaviors from scatters of material culture. However, in the interpretation of the archaeological record, particular attention must be given to disturbance factors that operate in post-depositional processes. In this paper, we answer the need for a specific taphonomic perspective in spatial analysis by applying point pattern analysis of taphonomic alterations on the faunal and lithic assemblages from the Early Pleistocene site of Pirro Nord 13, Italy. The site, biochronologically dated between 1.3 and 1.6 Ma BP, provides evidence for an early hominin presence in Europe. The archaeological and paleontological deposits occur as filling of a karst structure that is currently exposed. We investigated the distribution of the archaeological and paleontological assemblages, as well as the distribution of identified taphonomic features, in order to evaluate the degree and reliability of the spatial association of the lithic artifacts with the faunal remains. Our results contribute to the interpretation of the diagenetic history of Pirro Nord 13 and support the stratigraphic integrity of the site
Effect of the Reference Design Parameters Assessment on the Behaviour of the IFMIF Liquid Lithium Target
No full textAccelerator Sustained Nuclear Systems Thermal-Hydraulics
No full textIn this paper some major achievements of two nuclear systems thermal-hydraulics methods development and application research activities are presented. Both methods development and ADS thermal-hydraulic design main results are described. Radial subassembly temperature profiles are given and data concerning the optimisation of peripheral pin circumferential thermal gradients are also talked over. IFMIF liquid Lithium Target was modelled and analysed basing on the most recent design parameters. Temperature and boiling margins profiles were outlined and critical design issues have been discussed
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