Numerical Study of the Oscillatory Convergence to the Attractor at the Edge of Chaos

This paper compares three different types of ``onset of chaos'' in the logistic and generalized logistic map: the Feigenbaum attractor at the end of the period doubling bifurcations; the tangent bifurcation at the border of the period three window; the transition to chaos in the generalized logistic with inflection 1/2 ($x_{n+1} = \mu x_{n}^{1/2}$), in which the main bifurcation cascade, as well as the bifurcations generated by the periodic windows in the chaotic region, collapse in a single point. The occupation number and the Tsallis entropy are studied. The different regimes of convergence to the attractor, starting from two kinds of far-from-equilibrium initial conditions, are distinguished by the presence or absence of log-log oscillations, by different power-law scalings and by a gap in the saturation levels. We show that the escort distribution implicit in the Tsallis entropy may tune the log-log oscillations or the crossover times.Comment: 10 pages, 5 figure

Fractures and lineaments of Sicily Island: Preliminary results on analog optical techniques

There are no author-identified significant results in this report

Results of Skylab investigation over Italy

The author has identified the following significant results. Multispectral high resolution photography of S190A was successfully applied to the detection of paleoriverbeds in flat lands. Results of SL-3 mission were compared to those of LANDSAT for two regional geological surveys (linear structures) on the islands of Sicily and Sardinia. On Sicily, the seasonal conditions were unfavorable for Skylab while LANDSAT played a major role in discovering long, unknown lineaments of great interest for the geodynamics of the area. On Sardinia, owing to the vegetation type and to the geomorphic conditions, the Skylab imagery was successfully employed to describe the network of linears, both regional and local. Results can be used to study the relationship between linears, actual fracturing and the occurrence of mineral deposits

Superquadratic behavior of upconversion luminescence transients in rare-earth-ion doped laser crystals

Inhomogeneous active-ion distributions in laser materials lead to strong deviations of upconversion versus direct luminescence transients from the quadratic law of energy-transfer upconversion. Measured luminescence decay curves in LaSc3(BO3)4:Nd3+ and GdVO4:Nd3+ confirm experimentally the predicted deviations. Differences in energy migration within the metastable level of Nd3+ are identified

Super-quadratic behavior of luminescence decay excited by energy-transfer upconversion

For several decades, energy-transfer upconversion (ETU) in rare-earth-ion doped systems [1,2] has attracted much attention, firstly, because of the fundamental interest in the physical nature of this process and, secondly, because of very practical considerations, namely the demonstration of near-infrared pumped visible light sources and, in reverse, the detrimental influence of ETU on the efficiency of infrared emitting systems.\ud We investigate fundamentally the behavior of infrared luminescence emitted directly from a metastable level and visible luminescence emitted after ETU from this level to higher-lying levels. Although these two luminescences are connected by the same metastable level and influenced by the same ETU process, the infrared luminescence probes all ions, while the visible luminescence probes only the class of ions susceptible to ETU [3]. A simple analytical model [4] predicts that such luminescence decay curves exhibit a super-quadratic dependence of upconversion on direct luminescence decay.\ud The Nd3+ ion can serve as a model system for such investigations. It exhibits strong ETU from the metastable 4F3/2 level. When doped into oxide matrices, the 4F3/2 level is the only metastable level. The Nd3+ energy levels excited by ETU decay by fast multiphonon relaxation and, hence, the weak visible fluorescence emitted from these levels represents a quasi instantaneous reaction on the dynamics of the 4F3/2 level. Experimental results obtained after pulsed laser excitation of Nd3+-doped oxide host materials show indeed a super-quadratic behavior of upconversion versus direct luminescence decay, in accordance with the model predictions [4].\ud \ud [1] F. Auzel, Proc. IEEE 1973, 6, 758\ud [2] J.C. Wright, Top. Appl. Phys. 1976, 15, 239\ud [3] M. Pollnau, D.R. Gamelin, S.R. Lüthi, H.U. Güdel, M.P. Hehlen, Phys. Rev. B 2000, 61, 3337\ud [4] M. Pollnau, J. Alloys Compd. 2002, 341, 5

Contribution of Skylab multispectral imagery to the remote sensing studies of Mount Etna volcano

There are no author-identified significant results in this report

Quality management in the industry 4.0 era

In the current competitive scenario, manufacturing companies are facing various challenges related to an increasing level of variability. This variability means different sets of dimensions such as demand, volume, process, technology, quality, customer behavior and supplier attitude, and transform the industrial systems engineering domain. A new paradigm tries to solve these challenges and solutions such as "the fourth industrial revolution" or "Industry 4.0" refers to new production patterns, including new technologies, productive factors and labor organizations, which are completely changing the production processes and developing high-efficiency production systems that make it possible to minimize production costs and improve production and product quality. Manufacturing companies need to achieve a substantial improvement in performance by manufacturing high-quality products and creating highly flexible systems that make it possible to maintain their efficiency even when demand varies dramatically. Tools for the management and optimization of quality are vitally important. In this way the adoption of highly flexible cyber physical production units permits the implementation of production processes capable of guaranteeing high-quality standards in the finished product, even in the case of small production lots. Industry 4.0 provides promising opportunities for quality management therefore, the purpose of this paper is to focus on the quality management and industry 4.0 concepts and analyze the current state of literature trying to understand the implications and opportunities for quality management in the industry 4.0 era

Stable water isotopes of precipitation and firn cores from the northern Antarctic Peninsula region as a proxy for climate reconstruction

In order to investigate the climate variability in the northern Antarctic Peninsula region, this paper focuses on the relationship between stable isotope content of precipitation and firn, and main meteorological variables (air temperature, relative humidity, sea surface temperature, and sea ice extent). Between 2008 and 2010, we collected precipitation samples and retrieved firn cores from several key sites in this region. We conclude that the deuterium excess oscillation represents a robust indicator of the meteorological variability on a seasonal to sub-seasonal scale. Low absolute deuterium excess values and the synchronous variation of both deuterium excess and air temperature imply that the evaporation of moisture occurs in the adjacent Southern Ocean. The δ<sup>18</sup>O-air temperature relationship is complicated and significant only at a (multi)seasonal scale. Backward trajectory calculations show that air-parcels arriving at the region during precipitation events predominantly originate at the South Pacific Ocean and Bellingshausen Sea. These investigations will be used as a calibration for ongoing and future research in the area, suggesting that appropriate locations for future ice core research are located above 600 m a.s.l. We selected the Plateau Laclavere, Antarctic Peninsula as the most promising site for a deeper drilling campaign