Time filter

Source Type

Armenise I.,CNR Institute of Inorganic Methodologies and Plasmas | Kustova E.V.,Saint Petersburg State University
Chemical Physics | Year: 2014

In the present paper, state-to-state model of vibrational-chemical kinetic and transport processes is applied to study heat and mass transfer in non-equilibrium flows of CO2 and air mixtures under atmospheric entry conditions. Different contributions to the heat flux typical for the state-to-state approach are considered: fluxes due to heat conduction, mass diffusion, thermal diffusion, and diffusion of vibrational energy. For several test cases, vibrational distributions, chemical composition, temperature profiles as well as the transport coefficients and heat flux are calculated along the stagnation line. Various models for diffusion velocities are considered. For a non-catalytic surface, the role of thermal diffusion process is found to be important in some test cases. Prandtl and Schmidt numbers are calculated along the stagnation line, and it is shown that they are essentially non-constant. The influence of Prandtl and Schmidt numbers on the diffusion velocities and heat flux is evaluated. © 2013 Elsevier B.V. All rights reserved.


Armenise I.,CNR Institute of Inorganic Methodologies and Plasmas | Kustova E.V.,Saint Petersburg State University
Chemical Physics | Year: 2013

State-to-state vibrational kinetics and transport models of a mixture containing triatomic CO2 molecules are developed. The models are implemented into a hypersonic boundary layer solver specially upgraded for this purpose. Although at the moment only vibrational-translational transitions in the bending mode (VT2), inter-mode exchanges within CO2 molecule (VV1-2-3), and inter-mode exchanges between molecules of different chemical species (VV1-2-CO) are taken into account, the approach can be generalized to include more complete kinetics. In order to overcome problems caused by the computational load of the state-to-state vibrational kinetics of a triatomic molecule, a Reduced Model is proposed and compared with the Full one. © 2013 Elsevier B.V. All rights reserved.


Senesi G.S.,CNR Institute of Inorganic Methodologies and Plasmas
Earth-Science Reviews | Year: 2014

Thanks to its unique, unprecedented and very appealing analytical capabilities and performances, the Laser-Induced Breakdown Spectroscopy (LIBS) technique has expanded rapidly in the last two decades in several fields of academic and applicative research, including the study of geomaterials. This review mainly consists of two parts, the first one provides a general and brief summary and discussion of the basic theory and principles of LIBS, the experimental set-up of conventional laboratory bench-top and portable, remote and stand-off configurations, the main methodologies of qualitative and quantitative LIBS analysis with the support of chemometric approaches, and the advantages and disadvantages of the technique. The second part aims to provide a comprehensive, detailed and adjourned at-my-best overview of the huge work done on LIBS applications to the study of geomaterials with focus on minerals and rocks. In particular, results obtained on element detection and quantification, identification, discrimination, classification, provenance, weathering and alteration of minerals, igneous, sedimentary and metamorphic rocks, gemstones, mine ores, archeological artifacts and speleothems, are reviewed and briefly discussed. The enormous efforts and remarkable progresses made in the last decade by several research groups on the potential and viable use of LIBS on robotic vehicles for studying meteorites and planetary analogue terrestrial rocks in simulated planetary conditions, have also been reviewed. © 2014 Elsevier B.V..


Iorio L.,CNR Institute of Inorganic Methodologies and Plasmas
International Journal of Modern Physics D | Year: 2015

The orbital dynamics of a test particle moving in the nonspherically symmetric field of a rotating oblate primary is impacted also by certain indirect, mixed effects arising from the interplay of the different Newtonian and post-Newtonian accelerations which induce known direct perturbations. We systematically calculate the indirect gravitoelectromagnetic shifts per orbit of the Keplerian orbital elements of the test particle arising from the crossing among the first even zonal harmonic J2 of the central body and the post-Newtonian static and stationary components of its gravitational field. We also work out the Newtonian shifts per orbit of order J22, and the direct post-Newtonian gravitoelectric effects of order J2c-2 arising from the equations of motion. In the case of both the indirect and direct gravitoelectric J2c-2 shifts, our calculation holds for an arbitrary orientation of the symmetry axis of the central body. We yield numerical estimates of their relative magnitudes for systems ranging from Earth's artificial satellites to stars orbiting supermassive black holes. As far as their measurability is concerned, highly elliptical orbital configuration are desirable. © 2015 World Scientific Publishing Company.


Iorio L.,CNR Institute of Inorganic Methodologies and Plasmas
International Journal of Modern Physics D | Year: 2015

Mindful of the anomalous perihelion precession of Mercury discovered by Le Verrier in the second half of the nineteenth century and its successful explanation by Einstein with his General Theory of Relativity in the early years of the twentieth century, discrepancies among observed effects in our Solar system and their theoretical predictions on the basis of the currently accepted laws of gravitation applied to known matter-energy distributions have the potential of paving the way for remarkable advances in fundamental physics. This is particularly important now more than ever, given that most of the universe seems to be made of unknown substances dubbed Dark Matter and Dark Energy. Should this not be directly the case, Solar system's anomalies could anyhow lead to advancements in either cumulative science, as shown to us by the discovery of Neptune in the first half of the nineteenth century, and technology itself. Moreover, investigations in one of such directions can serendipitously enrich the other one as well. The current status of some alleged gravitational anomalies in the Solar system is critically reviewed. They are: (a) Possible anomalous advances of planetary perihelia. (b) Unexplained orbital residuals of a recently discovered moon of Uranus (Mab). (c) The lingering unexplained secular increase of the eccentricity of the orbit of the Moon. (d) The so-called Faint Young Sun Paradox. (e) The secular decrease of the mass parameter of the Sun. (f) The Flyby Anomaly. (g) The Pioneer Anomaly. (h) The anomalous secular increase of the astronomical unit. © 2015 World Scientific Publishing Company.


Taccogna F.,CNR Institute of Inorganic Methodologies and Plasmas | Mizzi G.,CNR Institute of Inorganic Methodologies and Plasmas
Contributions to Plasma Physics | Year: 2014

In this second paper, the effect of secondary electrons on the charge and potential of a dust particle immersed in plasma has been studied. The processes of electron-induced ionization and those of photo-electron and secondary electron emission from the particle surface as a function of primary electron temperature have been taken into account. Starting from temperatures as low as 6 eV in an Ar plasma, ionization produces an extra ion flux to the dust surface comparable to that of the ion charge exchange effect. For what concerns the surface emission, results show that a transition from negative to positive dust charge/potential takes place, and that the transition regime is characterized by a non-monotonic behavior of the electric potential around the particle. In the case of photoelectric emission, the dust charge and potential are monotonic decreasing functions of the electron temperature, while in the case of emission induced by primary electrons a minimum charge/potential is reached before they grow towards positive values. In no case multiple dust charge states have been observed due to the presence of the potential well attached to the particle surface. © 2014.


Dilecce G.,CNR Institute of Inorganic Methodologies and Plasmas
Plasma Sources Science and Technology | Year: 2014

In this paper we review the application of classical optical spectroscopy techniques, optical emission spectroscopy, laser-induced fluorescence (LIF) and absorption, to atmospheric-pressure discharges, with special emphasis on the importance of collision-induced transformations in electronic excited states. Collision processes will be reviewed that are relevant to the main atomic and molecular radicals of interest in the actual application framework. A critical discussion will be devoted to the available rate constant data for collision quenching and vibrational relaxation of N2(C3Π u, v = 0-4) and N2(B2∑u +, whose emissions are used for the spectroscopic determination of the reduced electric field by the nitrogen band ratio method. A further detailed discussion will address LIF measurements of OH in unknown He(Ar) + humid air mixtures. © 2014 IOP Publishing Ltd.


Cicala G.,CNR Institute of Inorganic Methodologies and Plasmas
Surface Engineering | Year: 2012

This review surveys the recent developments in the plasma deposition of polycrystalline diamond (PCD) films from highly diluted (1%CH 4 in H 2) gas mixture and superhydrophobic fluorocarbon films from C 2F 4 gas. Specifically, the pulsed plasmas are also used and examined at different duty cycles and pulse periods. Emphasis is given to the role of pulsed plasmas with respect to continuous ones in controlling the gas surface interaction and the growth chemistry and in determining the material properties. The obtained materials have been characterised using a wide range of methods: scanning electron microscopy, atomic force microscopy, Raman spectroscopy, X-ray diffractometry, spectroscopic ellipsometry, water contact angle, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Power modulation affects the PCD film morphology but deteriorates their optical and structural properties: the refractive index and the quality factor of continuous films are better than pulsed ones. As for fluorocarbon films, the control of both the plasma phase and the film deposited is improved under pulsed conditions. The pulsed plasmas, contrary to the continuous ones, allow to tune the CF 2 growth precursor and correspondingly the composition, structure and morphology of the film, exhibiting a superwater repellent surface with contact angles of up to 170°. © 2012 Institute of Materials, Minerals and Mining.


Taccogna F.,CNR Institute of Inorganic Methodologies and Plasmas
Contributions to Plasma Physics | Year: 2012

A fully kinetic self-consistent model of an absorbing particle immersed in stationary isotropic weakly collisional plasma has been developed. The combined effects of particle size and ion-neutral charge exchange collisions have been investigated for intermediate regimes, where no analytic theories are available. It is shown that collisional effects related to the ion orbital destruction (presence of extrema in ion flux collected on the particle surface and in particle potential and charge) are important for small particles, while they are totally absent for large particles. The potential distribution around the particle is quite well represented by a Yukawa form, but with an effective screening length that shows different dependences from the gas pressure for small and large particle size. Analytical fitting formulas of particle charge and potential and screening length depending on the particle radius parameter and on the Knudsen number have been obtained. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Favia P.,CNR Institute of Inorganic Methodologies and Plasmas
Surface and Coatings Technology | Year: 2012

Surface modification techniques based on plasma processes allow to tune surface composition, morphology and properties of materials in several applications. This short review is aimed to list, according to the knowledge of the author, established and recently reported plasma deposition processes of teflon-like" and PEO-like coatings to be used, in biomedical applications, to tailor at the best surface composition and morphology of biomaterials and biomedical devices to drive the interactions of proteins, cells, bacteria and biological tissues in contact with them. © 2012 Elsevier B.V.

Loading CNR Institute of Inorganic Methodologies and Plasmas collaborators
Loading CNR Institute of Inorganic Methodologies and Plasmas collaborators