Search results for " white"

Probabilistic characterization of nonlinear systems under Poisson white noise parametric input via complex fractional moments

2014

In this paper the probabilistic characterization of a nonlinear system enforced by parametric Poissonian white noise in terms of complex fractional moments is presented. In fact the initial system driven by a parametric input could be transformed into a system with an external type of excitation through an invertible nonlinear transformation. It is shown that by using Mellin transform theorem and related concepts, the solution of the Kolmogorov-Feller equation for the system with external input may be obtained in a very easy way.

Metabolic syndrome and cardiac morphofunctional changes in subjects with white-coat hypertension

2007

The Mafia Boss Yesterday and Today: Psychological Characteristics and Research Data

2015

This article describes Cosa Nostra bosses’ psychological characteristics starting from research data collected over almost twenty years (1994–2013). Through the use of fragments of interviews to justice collaborators and their wives, children, and sisters-in-law, we analyze the boss’ role and relational context. This article also reports the results of a recent research on the relationship between boss and white-collar workers, carried out through the analysis of environmental tapping recorded at a famous Sicilian Mafia boss’ house: Giuseppe Guttadauro. This research highlights the psychological diversity the relationship between boss and white-collar worker is based on. The analysis of env…

Effects of elevated hydrogen peroxide 'strip' bleaching on surface and subsurface enamel including subsurface histomorphology, micro-chemical composi…

2007

Abstract Objectives This study examined the effects of elevated concentration hydrogen peroxide tooth whitening treatments on tooth surface and subsurface integrity. Methods Sound human molars were ground and polished to prepare an uniform substrate for bleaching treatments. A cycling treatment included alternating ex vivo human salivary exposures with bleaching treatments under conditions of controlled temperature and durations of treatment. Bleaching was carried out with prototype bleaching strips containing hydrogen peroxide gel at 13% and 16% concentrations. A non-bleached group was used as a control. Treatments included 28 h of total bleaching exposure in vitro . Surface color was meas…

Effect of Hydrogen and Carbamide Peroxide in Bleaching, Enamel Morphology, and Mineral Composition: In vitro Study

2017

ABSTRACT Aim The aim of the study was to evaluate the bleaching effect, morphological changes, and variations in calcium (Ca) and phosphate (P) in the enamel with hydrogen peroxide (HP) and carbamide peroxide (CP) after the use of different application regimens. Materials and methods Four groups of five teeth were randomly assigned, according to the treatment protocol: HP 37.5% applied for 30 or 60 minutes (HP30, HP60), CP 16% applied for 14 or 28 hours (CP14, CP28). Changes in dental color were evaluated, according to the following formula: ΔE = [(La−Lb)2+(aa−ab)2 + (ba−bb)2]½. Enamel morphology and Ca and P compositions were evaluated by confocal laser scanning microscope and environmenta…

Ce:YAG nanoparticles embedded in a PMMA matrix: preparation and characterization

2010

A Ce:YAG-poly(methyl methacrylate) composite was prepared using in situ polymerization by embedding the Ce:YAG nanopowder in a blend of methyl methacrylate (MMA) and 2-methacrylic acid (MAA) monomers and activating the photopolymerization using a radical initiator. The obtained nanocomposite was yellow and transparent. Its characterization was performed using transmission electron microscopy, small angle X-ray scattering, (13)C cross-polarization magic-angle spinning nuclear magnetic resonance, and photoluminescence spectroscopy. Results showed that Ce:YAG nanoparticles are well dispersed in the polymeric matrix whose structure is organized in a lamellar shape. The luminescence properties o…

Skewness and kurtosis of 1/f noise in semiconductor devices

2000

An experimental investigation of the third and fourth moments of the 1/f noise of two different electronic devices is reported. The skewness and the kurtosis of the noise voltage data are estimated. Although the devices under investigation have similar noise power spectral density, the time waveforms are shown to have slightly different statistical properties. In both cases, a small deviation from Gaussian distribution is observed.

Stochastic response of linear and non-linear systems to α-stable Lévy white noises

2005

Abstract The stochastic response of linear and non-linear systems to external α -stable Levy white noises is investigated. In the literature, a differential equation in the characteristic function (CF) of the response has been recently derived for scalar systems only, within the theory of the so-called fractional Einstein–Smoluchowsky equations (FESEs). Herein, it is shown that the same equation may be built by rules of stochastic differential calculus, previously applied by one of the authors to systems driven by arbitrary delta-correlated processes. In this context, a straightforward formulation for multi-degree-of-freedom (MDOF) systems is also developed. Approximate CF solutions to the …

Stochastic analysis of a non-local fractional viscoelastic beam forced by Gaussian white noise

2017

Recently, a displacement-based non-local beam model has been developed and the relative finite element (FE) formulation with closed-form expressions of the elastic and fractional viscoelastic matrices has also been obtained. The static and quasi-static response has been already investigated. This work investigates the stochastic response of the non-local fractional viscoelastic beam, forced by a Gaussian white noise. In this context, by taking into account the mass of the beam, the system of coupled fractional differential equations ruling the beam motion can be decoupled with the method of the fractional order state variable expansion and statistics of the motion of the beam can be readily…

Path integral method for first-passage probability determination of nonlinear systems under levy white noise

2015

In this paper the problem of the first-passage probabilities determination of nonlinear systems under alpha-stable Lévy white noises is addressed. Based on the properties of alpha-stable random variables and processes, the Path Integral method is extended to deal with nonlinear systems driven by Lévy white noises with a generic value of the stability index alpha. Furthermore, the determination of reliability functions and first-passage time probability density functions is handled step-by-step through a modification of the Path Integral technique. Comparison with pertinent Monte Carlo simulation reveals the excellent accuracy of the proposed method.