First direct measurement of the total cross-section of 12C(α,γ)16O

The total cross-section of ¹²C(α,γ)¹⁶O was measured for the first time by a direct and ungated detection of the ¹⁶O recoils. This measurement in inverse kinematics using the recoil mass separator ERNA in combination with a windowless He gas target allowed to collect data with high precision in the energy range E = 1.9 to 4.9 MeV. The data represent new information for the determination of the astrophysical S(E) factor.     

Ab initio hartree-fock investigation of beryllium slabs

An analysis of the electronic structure in beryllium slabs with an ab initio LCAO HF method is presented. Band structure, electronic density and density of states were determined for thin films of 1 to 4 atomic layers of Be. A comparison of the electronic structure in films of different thickness with the situation found for bulk Be and Be clusters shows strong modifications in the surface region and a progressive reconstruction of the bulk bonds.     

Spectral density method in classical statistical mechanics

The spectral density method in classical statistical mechanics is formulated and application to a linear classical spin system is made in the simplest approximation.     

Geometry of Vlasov kinetic moments: A bosonic Fock space for the symmetric Schouten bracket

The dynamics of Vlasov kinetic moments is shown to be Lie-Poisson on the dual Lie algebra of symmetric contravariant tensor fields. The corresponding Lie bracket is identified with the symmetric Schouten bracket and the moment Lie algebra is related with a bundle of bosonic Fock spaces, where creation and annihilation operators are used to construct the cold plasma closure. Kinetic moments are also shown to define a momentum map, which is infinitesimally equivariant. This momentum map is the dual of a Lie algebra homomorphism, defined through the Schouten bracket. Finally the moment Lie-Poisson bracket is extended to anisotropic interactions.     

Development and Validation of Hierarchical Models for the Design of Engine Control Strategies

The development of mathematical models for the design of controlstrategies for spark ignition automotive engines is described. The objectiveof the models, used for both simulation and optimization analysis, is theprediction of the effects of control strategies on fuel consumption andemissions of a vehicle over arbitrary driving cycles. In order to achievethe best compromise between precision, experimental costs, computationaltime and flexibility, a mixed modelling approach is used, withphenomenological and input-output models integrated within a hierarchicalsystem.Mean value models have been used to describe the most significant dynamiceffects: (i) air flow. (ii) two phases fuel flow in the intake manifold, and(iii) thermal flow in the cylinder walls. Stochastic effects due to sensorsand actuators can be also predicted.Two-zone and multizone thermodynamic models for the prediction ofpressure cycle sub-models for engine emissions (HC, CO, andNO _x and mechanical losses have been developed. Experimentaldesign techniques are also under development to optimize the interactionsbetween experimental analysis and models. Most of the models have beenintegrated in a computer code, used by a major automotive supplier.     

Water dissociation at MgO sub-monolayers on silver: a periodic model study

A hybrid-exchange DFT hamiltonian and a periodic slab model have been employed to simulate water dissociation at the border of sub-monolayer MgO films deposited on Ag(100). Non-polar and polar borders have been considered, but the reaction energy is higher in the former case. The O-1s core level shifts and the O-H vibrational frequencies have been calculated and shown to be compatible with recent XPS and HREELS data, respectively [Savio et al., J. Chem. Phys., 2003, 119, 12053].