21 research outputs found
Hybrid neutron stars within the Nambu-Jona-Lasinio model and confinement
Recently, it has been shown that the standard Nambu-Jona-Lasinio (NJL) model
is not able to reproduce the correct QCD behavior of the gap equation at large
density, and therefore a different cutoff procedure at large momenta has ben
proposed. We found that, even with this density dependent cutoff procedure, the
pure quark phase in neutron stars (NS) interiors is unstable, and we argue that
this could be related to the lack of confinement in the original NJL model.Comment: 2 pages, 1 figure, to be published in the proceedings of the
conference EXOCT07, Catania, 11-15 June, 200
Validation of a non-contact technique for torque measurements in wind turbines using an enhanced transient FSV approach
In-service turbine monitoring is essential for maximizing the wind energy contribution to the global energy budget. Measurement of turbine shaft torque under transient wind conditions is fundamental to develop reliable condition monitoring techniques. Contact based measurements bring their own disadvantages and non-contactless measurements have many potential advantages. However, their performance needs to be validated against standard methods. This paper focuses on the development of an enhanced transient Feature Selective Validation (FSV) techniques to undertake this analysis with an emphasis on transient data processing. The nature of FSV makes it a natural technique to consider for this problem space. Open questions have existed as to how transients should be dealt with in FSV. This paper overcomes the limitations of previous approaches for step-function transient comparison and presents analytical methods to ensure the transient feature itself is considered, irrespective of how much pre- and post- transient data happens to be included
Non-perturbative renormalization group approach for a scalar theory in higher-derivative gravity
A renormalization group study of a scalar theory coupled to gravity through a
general functional dependence on the Ricci scalar in the action is discussed. A
set of non-perturbative flow equations governing the evolution of the new
interaction terms generated in both local potential and wavefunction
renomalization is derived. It is shown for a specific model that these new
terms play an important role in determining the scaling behavior of the system
above the mass of the inflaton field.Comment: 26 pages, RevTeX, five figure
Introduction of nitrogen functionalities into (R)-1-fluoro-3-(p-tolylsulfinyl)propan-2-one
Nitrogen functionalities have been introduced on C-2 and C-3 of (R)-1-fluoro-3-(p- tolylsulfinyl)propan-2-one (1) through high yield elaborations of the carbonyl and sulfinyl groups, respectively
Estimation of ageing of proper elements from the observed structures of asteroid families
The possible presence of noise affecting the proper elements of asteroid families (due to several dynamical and also physical effects) influences the reconstruction of the original velocity fields. A noise on eccentricities alone is not sufficient to explain the observed features, and a noise on semimajor axes must also be taken into account. A preliminary quantitative evaluation of these noises on both elements is attempted
The role of viscosity in AGN outflows in relation to jet periodicities
Aims. Adopting the Smoothed Particle Hydrodynamics (SPH) numerical method, we performed a grid of evolving models of a 3D axially-symmetric, viscous accretion disc around a supermassive black hole (SMBH) of . Such sort of simulations are typical of accretion discs in active galactic nuclei (AGN). In such disc models, we pay attention to the role of the specific angular momentum λ and the turbulent viscosity parameter α, according to the Shakura and Sunyaev prescription. One or two shock fronts in the radial inviscid flow develop, according to the assigned initial kinematic and thermodynamic conditions.
Methods. By fixing the initial and boundary conditions on the flow at the disc outer edge, where the total energy, the specific angular momentum λ, and the initial velocity are concerned, we find pairs of (α, λ) values determining radial periodical oscillations in the shock front. In some cases, an outflow develops from the subsonic post-shock region, close to the black hole.
Results. The link between the accretion disc and the jet refueling through the onset of a centrifugal shock front is evident. We also compare model variability periods with observed ones in the radio light curves of AGN