Thermal transformations of Cu–Mg (Zn)–Al(Fe) hydrotalcite-like materials into metal oxide systems and their catalytic activity in selective oxidation of ammonia to dinitrogen

Layered double hydroxides (LDHs) containing Mg^{2+}, Cu^{2+} or Zn^{2+} cations in the Me^{II} positions and Al^{3+} and Fe^{3+} in the Me^{III} positions were synthesized by co- precipitation method. Detailed studies of thermal trans- formation of obtained LDHs into metal oxide systems were performed using high temperature X-ray diffraction in oxidising and reducing atmosphere, thermogravimetry coupled with mass spectrometry and temperature-pro- grammed reduction. The LDH samples calcined at 600 and 900 °C were tested in the role of catalysts for selective oxidation of ammonia into nitrogen and water vapour. It was shown that all copper congaing samples presented high catalytic activity and additionally, for the Cu–Mg–Al and Cu–Mg–Fe hydrotalcite samples calcined at 600 °C rela- tively high stability and selectivity to dinitrogen was obtained. An increase in calcination temperature to 900 °C resulted in a decrease of their catalytic activity, possibly due to formation of well-crystallised metal oxide phase which are less catalytically active in the process of selective oxidation of ammonia

Synthesis and characterisation of coating polyurethane cationomers containing fluorine built-in hard urethane segments

Polyurethane cationomers were synthesised in the reaction of 4,4’-methylenebis(phenyl isocyanate) with polyoxyethylene glycol (M = 2,000) or poly(tetrafluoroethyleneoxide-co-difluoromethylene oxide) α,ω-diisocyanate and N-methyl diethanolamine. Amine segments were built-in to the urethane-isocyanate prepolymer in the reaction with 1-bromobutane or formic acid, and then they were converted to alkylammonium cations. The obtained isocyanate prepolymers were then extended in the aqueous medium that yielded stable aqueous dispersions which were applied on the surfaces of test poly(tetrafluoroethylene) plates. After evaporation of water, the dispersions formed thin polymer coatings. 1H, 13C NMR and IR spectral methods were employed to confirm chemical structures of synthesised cationomers. Based on 1H NMR and IR spectra, the factors κ and α were calculated, which represented the polarity level of the obtained cationomers. The DSC, wide angle X-ray scattering and atom force microscopy methods were employed for the microstructural assessment of the obtained materials. Changes were discussed in the surface free energy and its components, as calculated independently according to the method suggested by van Oss–Good, in relation to chemical and physical structures of cationomers as well as morphology of coating surfaces obtained from those cationomers. Fluorine incorporated into cationomers (about 30%) contributed to lower surface free energy values, down to about 15 mJ/m2. That was caused by gradual weakening of long-range interactions within which the highest share is taken by dispersion interactions

Ocena jakości wybranych stron internetowych sektora książkowego

The purpose of this article is to evaluate and select websites in Polish book sector with regard to quality measured by their usefulness for an individual client. First, the author has presented characteristics of the sector and basic methodological assumptions of the study. Next, he has conducted evaluations by means of a simple scoring method, a scoring method with preferences and relational research using T. Saaty's AHP (Analytic Hierarchy Process) method. The findings have been analysed and the author has compared the results of the study. (JEL: L15, VL81, C88).Celem artykułu jest ocena i wybór stron internetowych polskiego sektora książkowego w odniesieniu do jakości otrzymanej pod względem przydatności tych stron dla klienta indywidualnego. W pierwszej części autor przedstawił charakterystykę sektora oraz podstawowe założenia metodologiczne dotyczące badania. Następnie przeprowadzono ocenę za pomocą prostej metody punktowej, metody punktowej z preferencjami oraz badanie relacyjne z wykorzystaniem metody AHP Saaty'ego (Analytic Hierarchy Process). Na końcu Autor przeanalizował wyniki badań oraz porównał ich rezultaty

Analiza wybranych serwisów i platform dystrybucji treści komercyjnych w Polsce

The aim of this article is to analyse the quality of selected commercial content distribution platforms in Poland at the beginning of 2014. The analysis was performed with the method of random sampling and produced objective results of assessment of the investigated services. In part one of the chapter I will formulate the aim and the objectives of the study. Consequently, I will perform a comparative analysis according to the selected criteria. The final part of the chapter contains conclusions drawn from the study.Celem niniejszego artykułu jest analiza jakości wybranych serwisów dystrybucji treści komercyjnych w Polsce na początku 2014 r. Analizy dokonano przy pomocy metody punktowej. Pozwoliło to uzyskać obiektywne wyniki oceny badanych serwisów. W części pierwszej formułowany jest cel oraz założenia pracy. Następnie zostaje przeprowadzona analiza porównawcza według wyróżnionych kryteriów. Ostatnia część zawiera wnioski wynikające z badania