56 resultados para 2299 Other Philosophy and Religious Studies


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By the 17th century Catholic orthodoxy had defined a range of propositions concerning the human soul as revealed by God and verifiable by natural reason. The writings of Rene Descartes display a consistent adherence to these orthodox propositions. The conclusion presents him as ultimately unsuccesful in convincing his contemporaries that his philosophy provided the rational demonstration of the key soul doctrines and that he was worthy of the title "Christian philosopher"

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The lithium fast-ion conductor, Li1+xAlxTi2−x(PO4)3 (LATP) has been modified via changes in stoichiometry during the processing steps. The resultant changes have been followed using 27Al MAS NMR, X-ray powder diffraction and impedance spectroscopy. The most important changes were those of the form Li1.3+4yAl0.3Ti1.7−y(PO4)3. It was possible to remove the AlPO4 phase (both tridymite and berlinite polymorphs), as monitored by X-ray diffractograms and 27Al NMR spectra. Consequently, these changes appear to result in increased grain boundary conductivity of the LATP material.

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We report spectroscopic results from investigations of a novel solid polymeric fast-ion-conductor based on poly(acrylonitrile), (PAN, of repeat unit [CH2CH(CN)]n), and the salt LiCF3SO3 . From NMR studies of the temperature and concentration dependencies of 7Li- and lH-NMR linewidths, we conclude that significant ionic motion occurs at temperatures close to the glass transition temperature of these polymer-in-salt electrolytes, in accordance with a recent report on the ionic conductivity. In the dilute salt-in-polymer regime, however, ionic motion appears mainly to be confined to local salt-rich domains, as determined from the dramatic composition dependence of the ionic conductivity. FT-Raman spectroscopy is used to directly probe the local chemical anionic environment, as well as the Li+–PAN interaction. The characteristic δs(CF3) mode of the CF3SO3 anion at ~750–780 cm−l shows that the ionic substructure is highly complex. Notably, no spectroscopic evidence of free anions is found even at relatively salt-depleted compositions (e.g. N:Li~60–10:1). A strong Li+–PAN interaction is manifested as a pronounced shift of the characteristic polymer C=N stretching mode, found at ~2244 cm−l in pure PAN, to ~2275 cm−l for Li+-coordinated C=N moieties. Our proton-NMR data suggest that upon complexation of PAN with LiCF3 SO3, the glass transition occurs at progressively lower temperatures.

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This thesis is a compilation of eighty publications on analytical, experimental and numerical studies on the mechanical, tribological and corrosion behaviour of metal matrix composites (MMCs). The models based on the interface between matrix and reinforcement behaviour help accurate prediction of density and locked up hysterysis-strain in the composites at elevated temperatures.

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A significant number of biosorption studies on the removal of heavy metal from aqueous solutions have been conducted worldwide. Nearly all of them have been directed towards optimizing biosorption parameters to obtain the highest removal efficiency while the rest of them are concerned with the biosorption mechanism. Combinations of FTIR, SEM-EDX, TEM as well as classical methods such as titrations are extremely useful in determining the main processes on the surfaces of biosorbents. Diverse functional groups represented by carboxyl, hydroxyl, sulfate and amino groups play significant roles in the biosorption process. Solution pH normally has a large impact on biosorption performance. In brief, ion exchange and complexation can be pointed out as the most prevalent mechanisms for the biosorption of most heavy metals.