[en] This report describes some experiences performed at the Research Center Saluggia of ENEA concerning low-level determination of plutonium in biological and environmental samples, with discussions of practical analytical problems. The main characteristics and properties of plutonium with emphasis to aqueous solutions chemistry and environmental behaviour are also reported

[en] A solution of the problem of the power and particle exhaust from the next step tokamaks, will require new techniques which redistribute the power entering the SOL onto much larger surface area than conventional divertor design permits, while maintaining good impurity retention in divertor volume and allowing for efficient helium pumping. Progress made in developing such techniques is discussed. Status of the modelling studies of dynamic gas target divertor and impurity seeded radiating divertors is presented. Recent results of experiments on radiative and gas target divertors are reviewed

[en] The functions of hypercomplex variable can be related to the physical fields. Following the Einstein's ideas, by which the Theory of General Relativity was developed, they want to verify if a generalisation is possible, in order to described the motion of a body in a gravitational field, by the geodesics in spaces ''deformed'' by functional transformations of hypercomplex variables. These number systems introduce new space symmetries. This paper is just a first step in the more extended study. As a first application they consider the ''commutative quaternions'' system that may be considered as a composition of complex and hyperbolic numbers. By using in this system the same functional transformations valid for the two dimensional case, elliptical geodesics are obtained, with the eccentricity related to the angle between the orbit plane and a reference plane. These geodesics do not describe the Kepler orbits, but they show a space anisotropy that might be related to planet orbits of the solar system

[en] The authors calculate nonperturbative O (Λ _QCD² / m_c²) corrections to the dilepton invariant mass spectrum and the forward-backward charge asymmetry in B → X_s e⁺e^- decay using a heavy quark expansion approach. The method has recently been used to estimate long-distance effects in B → X_s γ. They generalize this analysis to the case of non-vanishing photon invariant mass, q² ≠ 0, relevant for the rare decay mode B → X_s e⁺e^-. In the phenomena-logically interesting q² region away from the cc-bar resonances, the heavy quark expansion approach should provide a reasonable description of possible non-perturbative corrections. In particular this picture is preferable to the model-dependent approach relying on the tails of Breit-Wigner resonances, which has been employed so far in the literature to account for these effects. They find that the O (Λ _QCD² / m_c²) corrections to the dilepton invariant mass spectrum and to the forward-backward asymmetry in B → X_s e⁺e^-amount to several percent at most for q² / m_b² ≤ 0.3 and q² / m_b² ≤ 0.6 respectively. The O (Λ _QCD² / m_c²) correction to the B → X_s γ decay rate is also computed and found to be +3 % which agrees in magnitude with previous calculations. Finally, they comment on long-distance effects in B → X_s v v-bar, which in this case are extremely suppressed due to the absence of virtual photon contributions

[en] An overview of the experiments for the search of gravitational waves by means of resonant detector is given. Since 1990 cryogenic resonant antennas have been in operation and data have been recorded by Explorer, Allegro, Niobe and Nautilus. The sensitivity for pulse detection with SNR = 1 is now h ≅ 6 10^-19 (corresponding to a total energy of less than 0.001 solar masses for a source in the Galactic Center). The sensitivity for monochromatic waves is h ≅ 2 10^-25 for one year of integration and about 7 10^-22/√Hz for a stochastic background detection. Large resonant detectors operating at 1 kHz might reach a spectral amplitude sensitivity of the order of 7 10^-24/√Hz and h = 3 10^-22 and h ≅ 10^-27. Cross-correlating two of such large antennas for one year can give a sensitivity for stochastic background detection of the order of 3 10^-26/√Hz corresponding to a ratio between the gw energy density to that needed for a close Universe of 10^-6

[en] In the last six years (1990-1996) the world wide capacity of grid connected offshore wind plants, at the prototypical stage, has reached 12 MW at energy costs some what higher than fifty per cent of similar on shore plants. Additional offshore installations are close to the construction and proposed for some hundreds MW in north european seas. The technology of the offshore wind turbines is evolving parallely to that of the onshore ones

[en] I=Y=0 16 plet mixing in SU(4) is discussed. The ideal values of newly introduced two angles in addition to that of Okubo in SU(3) is determined. The result is applied to amplitude relations for the two-body photonic decay of vector mesons. There is some inhibition factor in J/psi decays, but no inconsistency among themselves by choosing angles close to the ideal ones

[en] A harmonic oscillator spectroscopy of meson states (Q antiQ) in the upsilon region is presented in close parallel with C antiC spectroscopy through e⁺e^- annihilation studies. The observed masses are reproduced through a quadratic mass formula with a suitable spring constant. Radiative (E1) decays which are predicted parameter-free through an extension of Schwinger's Partial Symmetry hypothesis, are found to be an important fraction of the total widths of the Q antiQ mesons

[en] The error introduced in the Pade approximation to the Brillouin Wigner equation by a truncation of the propagators is bounded in a very simple way

[en] Much research work was and is still carried out at CISE on the thermal-hydraulic behaviour of two-phase mixtures, in the frame of researches concerning HWBLWR reactors, such as CIRENE, and BWR reactors. In this frame much attention has been devoted, among others, to pressure drop problems. This article presents a new correlation (DIF-2) developed at CISE for predicting two-phase pressure drops, which is a generalization of a previous correlation (DIF-1), published in 1972. DIF-2 envisages the usual breakdown of total pressure drops according to the energy balance; only the friction term is empirically correlated by a general expression, where all the parameters are grouped into two dimensionless numbers. By means of suitable weight functions, also the single-phase friction coefficients are taken into account, in order to have a smooth transition in correspondence with the gas weight friction values equal to 0 an 1. The correlation, when compared with the experimental data, presents a satisfactory reliability in a wide range of parameters. Anyway, it can be easily modified to better represent the conditions of interest. A remarkable analogy with single-phase correlations is also evident