Object oriented data analysis in ALEPH

This article describes the status of the ALPHA^{++} project of the ALEPH collaboration. The ALEPH data have been converted from Fortran data structures (BOS banks) into C^{++} objects and stored in a object oriented database (Objectivity/DB), using tools provided by the RD45 collaboration and the LHC^{++} software project at CERN. A description of the database setup and of a preliminary version of an object oriented analysis program is given.This article describes the status of the ALPHA^{++} project of the ALEPH collaboration. The ALEPH data have been converted from Fortran data structures (BOS banks) into C^{++} objects and stored in a object oriented database (Objectivity/DB), using tools provided by the RD45 collaboration and the LHC^{++} software project at CERN. A description of the database setup and of a preliminary version of an object oriented analysis program is given

Source of gold in Neoarchean orogenic-type deposits in the North Atlantic Craton, Greenland: Insights for a proto-source of gold in sub-seafloor

Given that gold (Au) mostly remained in the incipient Earth mantle until ca. 3.9–3.8 Ga, a “proto-source” of gold may have been present in the dominantly mafic crust precursor born through first-stage melting of the early Earth mantle. In south-westernmost Greenland, a fragment of the North Atlantic Craton is characterised by greenstone belts comprising mafic volcanic and magmatic rocks, and harzburgite cumulates that were emplaced at ca.3.0 Ga prograde amphibolite-facies metamorphic assemblages and caused local dissolution of arsenopyrite. During this retrograde tectono-metamorphic stage, in gold-rich shear zones, the Re- Os geochronometer in arsenopyrite was reset to a Neoarchean age while invisible gold was liberated and deposited as free gold with 2.66 Ga pyrite (Re-Os isochron ages). The initial Os isotope ratios of Neoarchean arsenopyrite ($^{187}$Os/$^{188}$Os$_{i}$ = 0.13 ± 0.02) and gold-bearing pyrite (0.12 ± 0.02) overlap with the estimated ($^{187}$Os/$^{188}$Os ratio of the Mesoarchean mantle (0.11 ± 0.01) and preclude contribution of radiogenic crustal Os from evolved lithologies in the accretionary arc complex, but instead, favour a local contribution in Os from basaltic rocks and serpentinised harzburgite protoliths by metamorphic fluids. Thus, the ca. 2.66 Ga lode gold mineralisation identified in the North Atlantic Craton may illustrate a gold endowment in shear zones in Earth’s stabilizing continental crust at the time of the 2.75–2.55 Ga Global Gold Event, through metamorphic upgrading of bulk gold which had originally been extracted from the Mesoarchean mantle and concentrated in hydrothermal arsenopyrite deposits in oceanic crust beneath the overall reduced Mesoarchean ocean

A New Point of View on Skin-Friction Contributions in Adverse-Pressure-gradient Turbulent Boundary Layers

Skin-friction decompositions such as the so-called FIK identity (Fukagata et al., 2002) are useful tools in identifying relevant contributions to the friction, but may also lead to results difficult to interpret when the total friction is recovered from cancellation of multiple terms with large values. We propose a new formulation of the FIK contributions related to streamwise inhomogeneity, which is derived from the convective form of the momentum equation and using the concept of dynamic pressure. We examine turbulent boundary layers subjected to various pressure-gradient conditions, including cases with drag-reducing control. The new formulation distinguishes more precisely the roles of the free-stream pressure distribution, wall-normal convection, and turbulent fluctuations. Our results allow to identify different regimes in adverse-pressure-gradient turbulent boundary layers, corresponding to different proportions of the various contributions, and suggest a possible direction towards studying the onset of mean separation

Aerodynamic Effects of Uniform Blowing and Suction on a NACA4412 Airfoil

We carried out high-fidelity large-eddy simulations to investigate the effects of uniform blowing and uniform suction on the aerodynamic efficiency of a NACA4412 airfoil at the moderate Reynolds number based on chord length and incoming velocity of Rec= 200 , 000. We found that uniform blowing applied at the suction side reduces the aerodynamics efficiency, while uniform suction increases it. This result is due to the combined impact of blowing and suction on skin friction, pressure drag and lift. When applied to the pressure side, uniform blowing improves aerodynamic efficiency. The Reynolds-number dependence of the relative contributions of pressure and friction to the total drag for the reference case is analysed via Reynolds-averaged Navier–Stokes simulations up to Rec= 10 , 000 , 000. The results suggest that our conclusions on the control effect can tentatively be extended to a broader range of Reynolds numbers

The dependence of the proton-triton thermo-nuclear fusion reaction rate on the temperature and total energy content of the high-energy proton distribution function

The endothermic nuclear reaction between thermal tritons and high-energy protons can represent an important contribution to the total neutron yield in tokamak plasmas heated by radio-frequency waves, as the first JET experiments have demonstrated (see Mantsinen et al 2001 Nucl. Fusion 41 1815). A further study based on more recent JET experiments was reported in Santala et al 2006 (Plasma Phys. Control. Fusion 48 1233). In this letter we supplement and complete the previous analysis by reporting the first systematic measurement of the scaling of the proton-triton (pT) thermo-nuclear fusion reaction rate as a function of the total energy content and perpendicular tail temperature of the fast protons heated by radio-frequency waves. It is found that the pT-neutron rate increases almost linearly with the fast proton temperature and the total energy content