Nanoparticle Langmuir-Blodgett Arrays for Sensing of CO and NO2 Gases

Metal oxide sensors with active Fe2O3 and CoFe2O4 nanoparticle arrays were studied. Sensing nanoparticle films from 1, 2, 4 or 7 monolayers were deposited by Langmuir-Blodgett technique. Sensors are formed on the alumina substrates equipped with heating meander. Langmuir-Blodgett layers were heated or UV irradiated to remove the insulating surfactant. Sensing properties were studied towards CO or NO2 gases in concentrations between 0.5 and 100 ppm in mixture with the dry air. Best response values Igas/Iair were obtained with CoFe2O4 device being 3 for 100 ppm of CO and with Fe2O3 device being (38)-1 for 0.5 ppm of NO2

L'architecture du système monétaire et financier international : nouvelles perspectives

Cette thèse vise à présenter des éléments nouveaux sur quelques questions clés relatives à l’architecture du système monétaire et financier international permettant d’éclairer les enjeux de son évolution possible au cours des années à venir. Les deux premiers chapitres présentent des éléments empiriques en faveur du « regard nouveau » sur la concurrence entre monnaies internationales. Ils étudient deux dimensions de l’utilisation internationale d’une monnaie, à savoir son rôle comme instrument de financement dans les marchés obligataires internationaux et celui de moyen de paiement des transactions internationales pour un bien homogène comme le pétrole. Le troisième chapitre met en lumière une source d’inertie dans le choix des monnaies internationales autre que les externalités et rendements croissants liées aux effets de réseau qui a attiré jusqu’à présent moins d’attention, à savoir les coûts fixes et les effets d’apprentissage endogènes. Le dernier chapitre identifie le risque d’aléa moral comme canal permettant à l’accumulation de réserves d’avoir des effets inflationnistes.This dissertation presents new evidence on selected issues relating to the architecture of the international monetary and financial system, which might help shed some light on its potential evolution in the period ahead. The first two chapters of the dissertation provide new evidence in support of the “new view”. They study two different dimensions of international currency use, namely the role of currencies as financing units in the global bond market and their role as means of payment in international transactions in homogenous goods, specifically in the global oil market. The third chapter sheds light on a source of persistence in international currency use besides network externalities and increasing returns which had attracted less attention hitherto, namely sunk costs and endogenous learning effects. The last chapter identifies moral hazard as a channel through which reserve accumulation can have inflationary effects

Kinetics and mechanism of the biodegradation of PLA/clay nanocomposites during thermophilic phase of composting process

The degradation mechanism and kinetics of polylactic acid (PLA) nanocomposite films, containing various commercially available native or organo-modified montmorillonites (MMT) prepared by melt blending, were studied under composting conditions in thermophilic phase of process and during abiotic hydrolysis and compared to the pure polymer. Described first order kinetic models were applied on the data from individual experiments by using non-linear regression procedures to calculate parameters characterizing aerobic composting and abiotic hydrolysis, such as carbon mineralization, hydrolysis rate constants and the length of lag phase. The study showed that the addition of nanoclay enhanced the biodegradation of PLA nanocomposites under composting conditions, when compared with pure PLA, particularly by shortening the lag phase at the beginning of the process. Whereas the lag phase of pure PLA was observed within 27 days, the onset of CO2 evolution for PLA with native MMT was detected after just 20 days, and from 13 to 16 days for PLA with organo-modified MMT. Similarly, the hydrolysis rate constants determined tended to be higher for PLA with organo-modified MMT, particularly for the sample PLA-10A with fastest degradation, in comparison with pure PLA. The acceleration of chain scission in PLA with nanoclays was confirmed by determining the resultant rate constants for the hydrolytical chain scission. The critical molecular weight for the hydrolysis of PLA was observed to be higher than the critical molecular weight for onset of PLA mineralization, suggesting that PLA chains must be further shortened so as to be assimilated by microorganisms. In conclusion, MMT fillers do not represent an obstacle to acceptance of the investigated materials in composting facilities. (C) 2015 Elsevier Ltd. All rights reserved.European Regional Development Fund (ERDF); national budget of the Czech Republic [CZ.1.05/2.1.00/03.0111]; Ministry of Education, Youth and Sports of the Czech Republic [LE12002]; [IGA/FT/2014/005

Nanoparticle Langmuir-Blodgett Arrays for Sensing of CO and NO2 Gases

Metal oxide sensors with active Fe2O3 and CoFe2O4 nanoparticle arrays were studied. Sensing nanoparticle films from 1, 2, 4 or 7 monolayers were deposited by Langmuir-Blodgett technique. Sensors are formed on the alumina substrates equipped with heating meander. Langmuir-Blodgett layers were heated or UV irradiated to remove the insulating surfactant. Sensing properties were studied towards CO or NO2 gases in concentrations between 0.5 and 100 ppm in mixture with the dry air. Best response values Igas/Iair were obtained with CoFe2O4 device being 3 for 100 ppm of CO and with Fe2O3 device being (38)-1 for 0.5 ppm of NO2