Ricerc@Sapienza

The effect of magnetic turbulence in shaping the current density profile in axisymmetric magnetized plasmas is analyzed using a turbulent extension of Ohm's law derived from the self-consistent action-angle transport theory. Besides the well-known hyper-resistive (helicity conserving) contribution, the generalized Ohm's law contains an anomalous resistivity term and a turbulent bootstrap-like term proportional to the current density derivative.

Spaceborne synthetic aperture radars (SARs) operating at L-band and above are nowadays a well-established tool for Earth remote sensing. In this respect, a new frontier of technological and scientific progress is represented by satellite Ka-Band SARs. Since approximately 2010, a number of European Space Agency (ESA) studies have been funded in this direction. The main identified benefit of Ka-band systems is that the short wavelength allows the implementation on a single platform of single-pass interferometry, both cross-track and along-track, with adequate interferometric sensitivity.

We show that Kerr beam self-cleaning results from parametric mode mixing instabilities that generate a number of nonlinearly interacting modes with randomized phases - optical wave turbulence, followed by a direct and inverse cascade towards high mode numbers and condensation into the fundamental mode, respectively. This optical self-organization effect is an analogue to wave condensation that is well known in hydrodynamic 2D turbulence.

The aim of this work was to investigate the aggregation of metallic iron nanoparticles in a Rushton equipped agitated vessel open at the atmosphere. The particles were synthetized using oxygen-free reagent solutions and subsequently were suspended in water in an open lab-scale agitated vessel. The particle size distribution, zeta-potential, pH and Fe(0) content were monitored over the time, up to the complete oxidation of the particles.

The aim of this work is to optimize iron nanoparticle production in stirred tank reactors equipped with two classical impellers: Rushton and four-pitched blade turbines, which are largely used in batch industrial synthesis and efficient scale-up. The main operative parameters of nanoparticle synthesis are the precursor initial concentration, reducing agent/precursor molar ratio, impeller–tank clearance, and impeller rotational velocity.

In recent decades, great progress has been made in our understanding of zonal jets across many subjects - atmospheric science, oceanography, planetary science, geophysical fluid dynamics, plasma physics, magnetohydrodynamics, turbulence theory - but communication between researchers from different fields has been weak or non-existent. Even the terminology in different fields may be so disparate that researchers working on similar problems do not understand each other. This comprehensive, multidisciplinary volume will break cross-disciplinary barriers and aid the advancement of the subject.