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Abstract  

The sorption of caesium and strontium from its aqueous solutions by ten clinoptilolite-and mordenite-containing sedimentary materials from Slovakia, Bulgaria, Ukraine and Greece was investigated by batch-type procedure and radiotracer techniques. The concentration of the solutions, that were performed in and without the presence of competing cations (0.005 mol·dm−3 KCl) varied between 1·10−4 and 5·10−2 mol·dm−3. The uptake and distribution coefficient (K d ) values determined for the materials of the different origin, were correlated with their mineralogical composition and gross cation exchange capacity (CEC). The identification of the specific uptake sites was attempted on the basis of the sorption isotherms and the content of exchangeable cations. The experimental results provide information on the suitability of the individual materials for the treatment of radioactive wastes and their application as backfills in potential nuclear waste repositories.

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Abstract

Chimetopon camerunensis Schmidt, 1910 from Equatorial Africa along with Oronoqua orellana Gnezdilov et Bartlett, 2020 and Sarnus rhomboidalis Fennah, 1965 from South America are included in the molecular analysis of the family Issidae for the first time. DNA of Ch. camerunensis was extracted from an old dry specimen collected more than 50 years ago. Based on our analysis, the tribe Chimetopini Gnezdilov, 2017 is nested within the subfamily Hysteropterinae, showing close relationships to North African and southern European genera Falcidius Stål, 1866 and Numidius Gnezdilov, Guglielmino et D'Urso, 2003. Additionally, we confirm the monophyly of the tribe Thioniini Melichar, 1906 and its position as a sister group to the tribe Issini Spinola, 1839 within the subfamily Issinae Spinola, 1839.

Open access

Abstract

The in situ electrical properties and the catalytic activity of copper ferrite obtained by co-precipitation and thermal decomposition of polynuclear coordination compounds were studied in the propane oxidation reaction. The sample prepared by complexation had a better catalytic activity. Based on the conductivity data and the relative phase distribution in fresh and used compounds, the results are discussed in terms of the redox-type mechanism.

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Thermal analysis of some polynuclear coordination compounds

Ligand tartarate, precursors of LnFeO3 perovskites

Journal of Thermal Analysis and Calorimetry
Authors:
L. Patron
,
P. Budrugeac
,
A. Balu
,
Oana Carp
,
L. Diamandescu
, and
M. Feder

Abstract  

The thermal behaviour of five polynuclear coordination compounds containing tartaric anion as ligand, namely (NH4)3[LnFe(C4O6H4)3(OH)3] (Ln=La and Eu), (NH4)2[PrFe(C4O6H4)3(OH)2] and (NH4)[LnFe(C4O6H4)3(OH)]3H2O (Ln=Nd and Gd) was investigated. The reaction progress was studied by TG/DTA and FTIR measurements. Oxalates and oxocarbonates were identified as intermediates. In the case of Ln=La, Nd, Pr, Eu and Gd, pure LnFeO3 was obtained as final decomposition product. The thermal decomposition of Eu-Fe compound, leads to a mixture of mixed (ortho-ferrite (EuFeO3) and garnet (Eu3Fe5O12)) and simple oxides (Eu2O3 and α-Fe2O3).

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Journal of Thermal Analysis and Calorimetry
Authors:
M. Feder
,
Maria Popescu
,
E. Segal
,
N. Dragoe
,
D. Crisan
, and
N. Dragan

The solid-state reaction between SrCO3 and α-FeOOH was investigated by means of thermal analysis, X-ray diffraction, electron microscopy and magnetic measurements. The high reactivity of this mixture is discussed in comparison with that of the mixture of SrCO3 and α-Fe2O3.

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Abstract

A rapid, stability indicating reverse phase liquid chromatographic method was developed for the determination of purity of Felodipine in active pharmaceutical substance form in the presence of its impurity and its degradation products. To develop the method which is also compatible to liquid chromatographic mass spectroscopic technique. The developed method is also used to determine the assay of Felodipine in bulk drug form. The drug is subjected to various stress conditions like acidic, basic, oxidation, UV light and thermal conditions. Considerable degradation was observed during base hydrolysis. Two degradation products were identified. The Waters Acquity UPLC BEH C18, 2.1 × 100 mm, 1.7 µm Column was used to achieve chromatographic separation. The gradient conditions, diluent and injection volume were optimized to achieve the acceptable resolution between impurities and its degradation products from Felodipine and to get good peak shapes. The masses were determined for main compound and its identified degradation products. Further, the characterization studies for main compound and its degradation products were performed using LCMSMS Q-TOF.

Open access