Fractional order modeling of rotor skin effect in induction machines

This paper presents a fractional Park model which is intended to characterize skin effect of squirrel cage induction machines. Usual modeling of skin effect is based on a ladder network; it is demonstrated that a fractional impedance is an alternative to this ladder network. The fractional Park’s model has been validated by output error identification. A methodology has been proposed to select the more appropriate fractional model of the rotor, respecting the diffusive nature of skin effect.     

Path tracking design based on Davidson–Cole prefilter using a centralized CRONE controller applied to multivariable systems

To perfectly govern MIMO (Multi-Input Multi-Output) processes, a fully populated matrix controller has been developed due to its flexibility. Taking into account the plant uncertainties, the CRONE (Commande Robuste d’Ordre Non Entier) control approach is used with the non-diagonal quantitative feedback theory (QFT) procedure. The MIMO-QFT robust synthesis methodology has been used in order to generate the appropriate equivalent MISO (Multi-Input Single-Output) system structure from the MIMO plant. For each MISO structure, the CRONE control approach based on third-generation CRONE methodology is used to find the diagonal elements of the controller of the plant while considering the plant uncertainties. The non-diagonal part of the controller is determined to reach the aim of minimizing the coupling effects. After that, a fractional prefilter synthesis approach is developed to find the non-integer prefilter expression satisfying the tracking specifications. A SCARA robot manipulator has been used to verify the designed controller performances.     

High efficiency second-harmonic generation in KNbO3 crystals

Second-harmonic generation in KNbO₃ crystals has been studied with CW and pulsed Al_xGa_1?xAs and dye lasers. High conversion efficiencies were obtained by noncritical Type I phase-matching at room temperature for the wavelength λ_PM = (860±2) nm using the nonlinear optical coefficient d₃₂ = 21 pm/V. The measured peak power was P_2ω=13.6 μW for a fundamental power P_ω=21 mW with a crystal of l = 8.97 mm in length. The phase-matching wavelength in the orthorhombic phase of KNbO₃ can be temperature tuned between 838 nm (for T = -36°C) and 950 nm (for T = +180°C).     

An Empirical Correction Term to Density Functional Theory for the Description of the TiCl4-Lewis Base Complexes

Calorimetric and computational investigation on the interaction of TiCl₄ with some Lewis bases (esters and ethers) is presented. The bases were chosen for their relevance in heterogeneous Ziegler-Natta polymerization of propene. Comparison of the theoretical data with the calorimetric data indicates that calculations consistently underestimate the experimental binding energies. In light of this consistency, we propose that an empirical correction term added to the theoretical binding energies could represent an empirical solution for the prediction of the TiCl₄/donor binding energies with reasonable accuracy.     

Uniqueness of form extensions and domination of semigroups

In this article, we study uniqueness of form extensions in a rather general setting. The method is based on the theory of ordered Hilbert spaces and the concept of domination of semigroups. Our main abstract result transfers uniqueness of form extension of a dominating form to that of a dominated form. This result can be applied to a multitude of examples including various magnetic Schrödinger forms on graphs and on manifolds.     

DMA analysis to predict the performance of waterborne coatings

In previous studies some waterborne coatings, specifically formulated for the scope of the research, were studied during an artificial weathering process by means of dynamic mechanical analysis (DMA) technique. In those studies the chemical and physical parameters which mainly affect the performance of coatings and their evolution during weathering were measured. The aim was to predict the performance of coatings for exterior wood during their service life by means of accelerated artificial tests and instrumental measures. In this study four commercial products were artificially weathered following the European standard EN 927-6. The changes in the mechanical properties were measured by means of the DMA as reported in the previous studies. With this research the authors have verified the capability of this method to predict the performance in use of coatings.     

Privileges of First-Person Reference and of Third-Person Reference

It is a widely held view that persons have privileged knowledge about their own minds, although numerous different views on what this privilege exactly consists of exist. One possible way of interpreting it is to claim that persons can refer to their own mental states in a privileged way. I will argue that this view has to be extended. Our common-sense view about reference to mental states implies that besides privileges of first-person reference to one's own mental states, there also exist privileges of third-person reference to the mental states of others: Other persons can refer to all of the mental states of a person in a way that the person cannot. In a next step, I will explain that persons can take two perspectives towards their own mental states: a first-person perspective and a third-person perspective. I will conclude that the possibilities of first-person reference from a third-person perspective are limited.