Influence of mechanochemical activation on the sintering of cordierite ceramics in the presence of Bi2O3 as a functional additive

Due to its outstanding electrical characteristics, such as the low temperature expansion coefficient, low dielectric constant and good mechanical properties, cordierite, 2MgO center dot 2Al(2)O(3)center dot 5SiO(2), is a very attractive high-temperature ceramic material. In order to accelerate the process of sintering, 2.50 mass% Bi2O3 has been added to the starting mixtures. Liquid phase sintering caused by the presence of bismuth-oxide lowers the temperature of cordierite formation. The mechanical activation of the starting mixtures (0-56 min in vibro-mill) additionally lowers sintering temperatures. The sintering process was performed at 1200, 1300, 1350 and 1400 degrees C, for 2 h. The particle size analysis (PSA) was employed in order to determine the changes in the particle size of the mechanically treated powders. The phase composition of the starting powders and sintered materials was analyzed by the X-ray diffraction method. Furthermore, scanning electron microscopy (SEM) was used in the analysis of the powder morphology. (C) 2011 Elsevier B.V. All rights reserved

Annealing effects on the microstructure and photoluminescence of Eu3+-doped GdVO4 powders

This work explores the influence of annealing temperature on microstructure and optical characteristics of Eu3+ doped GdVO4 (0.5, 1, 2 and 3 at.% Eu3+) nanopowders produced via co-precipitation synthesis. Samples were annealed at different temperatures (300 degrees C, 600 degrees C, 800 degrees C and 1000 degrees C) for 2 h and XRD analyses confirmed their tetragonal zircon structure. As-synthesized powders were composed of nanorods (diameter similar to 5 nm, length similar to 20 nm) organized in bundles, which by annealing grew to faceted crystals of round and rectangular shape (50-150 nm in size). Energy band gap shifts to higher energy (3.56 eV -> 3.72 eV) with decreasing crystallite size (43 nm -> 13 nm). Photoluminescence emission spectra were recorded using two different excitation wavelengths: lambda(ex) = 330 nm and lambda(ex) = 466 nm, aiming to excite directly the host matrix and Eu3+ ions, respectively. The intensity of most pronounced red transitions is one order of magnitude higher for lambda(ex) = 330 nm due to a strong energy absorption of VO43- groups, followed by efficient energy transfer to Eu3+ ions. We investigated the influence of annealing temperature and concentration of Eu3+ ions on the optical properties, namely photoluminescence emission and excitation, and decay time. The maximum intensity of D-5(0) -> F-7(2) red emission is observed for sample treated at 1000 degrees C, containing 2 at.% of Eu3+ ions. With the increase of Eu3+ concentration (0.5-3 at.%) the decay time of D-5(0) -> F-7(2) transition decreases from similar to 1 ms to 0.5 ms. (c) 2013 Elsevier B.V. All rights reserved

Isothermal sintering of barium-zinc-titanate ceramics

Mixtures of BaCO(3)-ZnO-TiO(2) were mechanically activated using high-energy planetary ball mill during 20, 40 and 80 min. As the time of mechanical activation increased, the decrease in particle size was observed. The effect of milling on microstructure was investigated by scanning electron microscopy, as well. Sintering process was performed in air at 1100 and 1200 C for 2 h. Various phases are present within mixtures sintered at 1100 and 1200 degrees C, and almost pure BaZn(2)Ti(4)O(11) phase was obtained after 80 min of milling and sintering at 1200 degrees C for 2 h. (C) 2010 Elsevier Ltd and Techna Group S.r.l. All rights reserved

Harmonizacja przepisów o zaskarżaniu i bezskuteczności czynności dłużnika

Książka jest wynikiem międzynarodowego projektu naukowego, którego celem było sformułowanie propozycji zharmonizowanych przepisów dotyczących bezskuteczności i zaskarżania czynności dłużnika w Unii Europejskiej. Projekt opiera się na 25 raportach krajowych (w tym dotyczącym prawa polskiego), na podstawie których sformułowano podstawowe zasady prawa w tym zakresie, a następnie sporządzono ustawę modelową będącą propozycją zharmonizowanych przepisów, które mogłyby zostać wprowadzone w drodze rozporządzenia albo dyrektywy UE. Projekt wpisuje się w długoterminowe plany legislacyjne UE w dziedzinie prawa upadłościowego i może zostać wzięty pod uwagę w pracach legislacyjnych.This book is the result of an intensive research project on transactions avoidance laws in the EU, comprising national reports and input from 25 jurisdictions and analysing the relevant topics from a principle-based perspective. The authors elaborate on the principles supporting and shaping transactions avoidance law, identifying the topics to be addressed from a principle-based perspective, and weighing and balancing the relevant principles to find adequate solutions for every single topic. The final result is a Model Law, comprising nine sections, which the authors recommend implementing into all national insolvency laws of the EU Member States in order to provide for legal certainty as to which transactions should (or should not) be challengeable in all Member States under the same conditions