A PDE based and interpolation-free framework for modeling the sifting process in a continuous domain

The empirical mode decomposition (EMD) is a powerful tool in signal processing. Despite its algorithmic origin making its theoretical analysis and formulation very difficult, a few recent works has contributed to its theoretical framework. Herein, the former local mean is formulated in a more convenient way by introducing operators to calculate local upper and lower envelopes. This enables the use of differential calculus and other classical calculations on the new local mean. Based on its more accurate formulation, a partial differential equation (PDE) consistency result is provided to approximate the sifting process iterations, without any envelope interpolation. In addition, a new stopping criterion based on the introduced local mean is proposed. This new criterion is a local measure and resolves the null integral conservative property of the previous derived PDE, which made any signal having a null integral be a PDE-based mode. Moreover, the δ inner model parameter is now linked to the signal intrinsic properties, providing to the latter a physical meaning and making the proposed model keep the auto-adaptive property of the EMD. New decomposition modes are now analytically and fully characterized, and also interpolation free. Finally, properties of the interpolation free PDE model are presented. Results obtained with our proposed approach by explicit computations thanks to the eigendecomposition of the Laplacian operator, and also by numerical resolution of the derived PDE, show noticeable improvements for both stationary and non stationary signals, in comparison to the former EMD algorithm.     

Energy dependence of the 6Li + 16O elastic scattering versus that of 7Li + 16O

The European Physical Journal A - Existing data for the 6Li + 16O elastic scattering at $ E_{c.m.}=3.27$ -36.8MeV were analyzed within the optical model and coupled-reaction-channels method. The...     

A Galois-Theoretic Approach to the Covering Theory of Quandles

The purpose of this article is to clarify the relationship between the algebraic notion of quandle covering introduced by M. Eisermann and the categorical notion of covering arising from Galois theory. A crucial role is played by the adjunction between the variety of quandles and its subvariety of trivial quandles.     

Sono and electrochemical synthesis and characterization of copper core–silver shell nanoparticles

Cu–Ag core–shell nanopowders have been prepared by ultrasound-assisted electrochemistry followed by a displacement reaction. The composition of the particles has been determined by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). The XRD patterns versus time displacement show that higher are the silver peaks intensities, weaker are the copper ones. That exhibits the progressive recovering of copper by silver. EDX results and quartz crystal microbalance results indicate that various reaction mechanisms are implied in this process. Transmission electron microscopy (TEM) points out variable nanometric diameter grain and some small agglomerates. Elemental mapping obtained by electron energy-loss spectroscopy (EELS) underlines the core–shell structure.     

A survey of dual-feasible and superadditive functions

Dual-feasible functions are valuable tools that can be used to compute both lower bounds for different combinatorial problems and valid inequalities for integer programs. Several families of functions have been used in the literature. Some of them were defined explicitly, and others not. One of the main objectives of this paper is to survey these functions, and to state results concerning their quality. We clearly identify dominant subsets of functions, i.e. those which may lead to better bounds or stronger cuts. We also describe different frameworks that can be used to create dual-feasible functions. With these frameworks, one can get a dominant function based on other ones. Two new families of dual-feasible functions obtained by applying these methods are proposed in this paper.     

Furazan-containing bromoarenes in the Suzuki-Miyaura reaction

The palladium-catalyzed cross-coupling reactions of 3-[bromo(het)aryl]furazans and bromobenzofurazans with arylboronic acids afford target biaryls in good yields. 3-Bromo-4-phenylfurazan containing a bromine atom in the furazan ring undergoes decomposition under the reaction conditions.     

Study of Electrical Conductivity of Para-Toluene Sulfonic Acid Doped Polyaniline/Polyester-Based Polyurethane Blends in the S-Band Frequency Range

Conducting polymer blends were prepared using polyaniline doped with para- toluene sulfonic acid (PTSA-PANI) and a polyester polyol-based polyurethane (PU). The morphological, thermal and dielectric properties of the PTSA-PANI/PU blends in the frequency range of 1–5 GHz (S band) were investigated. It was found that the morphology of the samples was affected by the PTSA-PANI loading, resulting in the formation of agglomerates and pathways when above 10 wt%. The thermal stability of the composites was improved with increased PTSA-PANI loading. The electrical conductivity percolation threshold was obtained at 2.5% of PTSA-PANI loading and the electrical conductivity reached the value of 0.13 S/m at a PTSA-PANI loading of 30 wt%. The obtained results for the PTSA-PANI/PU blends prepared indicate a high potential for their successful use in electrical and electromagnetic applications.     

Synthesis of azafluorenones and related compounds using deprotocupration–aroylation followed by intramolecular direct arylation

The efficiency of the deprotocupration–aroylation of 2-chloropyridine using lithiocuprates prepared from CuX (X=Cl, Br) and LiTMP (TMP=2,2,6,6-tetramethylpiperidido, 2 equiv) was investigated. CuCl was identified as a more suitable copper source than CuBr for this purpose. Different diaryl ketones bearing a halogen at the 2 position of one of the aryl groups were synthesized in this way from azines and thiophenes. These were then involved in palladium-catalyzed ring closure: substrates underwent expected CH-activation-type arylation to afford fluorenone-type compounds, and were also subjected to cyclization reactions leading to xanthones, notably in the presence of oxygen-containing substituents or reagents.     

Calorimetric determination of the effect of additives on cement hydration process

Possibilities of a multicell isoperibolic-semiadiabatic calorimeter application for the measurement of hydration heat and maximum temperature reached in mixtures of various compositions during their setting and early stages of hardening are presented. Measurements were aimed to determine the impact of selected components?? content on the course of ordinary Portland cement (OPC) hydration. The following components were selected for the determination of the hydration behaviour in mixtures: very finely ground granulated blast furnace slag (GBFS), silica fume (microsilica, SF), finely ground quartz sand (FGQ), and calcined bauxite (CB). A commercial polycarboxylate type superplasticizer was also added to the selected mixtures. All maximum temperatures measured for selected mineral components were lower than that reached for cement. The maximum temperature increased with the decreasing amount of components in the mixture for all components except for silica fume. For all components, except for CB, the values of total released heat were higher than those for pure Portland cement samples.