Sorption of Rare-earth Elements and Ac on DN resin with HCl,HClO4, CH3COOH,CCl3COOH

ABSTRACT

The distribution of some rare-earth elements (REE) on DN resin (TODGA loaded resin by Triskem international) was determined from different concentrations of two inorganic (HCl, HClO₄) and two organic acids (CH₃COOH, CCl₃COOH). The separation of Ac from REE is researched, as well as some separation possibilities of the elements within the REE. The determined distribution coefficients allows the prediction of the elution profiles of the researched elements. Using the obtained results in this work further applications can be considered.     

Model-checking the preservation of temporal properties upon feature integration

Updating a system by adding new features to it is a technique which enables designs and code to be reused. However, adding new features can remove some properties of the system, as well as adding other ones. Model checking can be used to check whether important properties have been lost when a feature was added, but, as is well-known, model checking is computationally expensive. In this paper, we develop a method which avoids the necessity to re-check certain properties of systems when a feature is added. The method provides criteria allowing us to deduce that the feature does not break a given property, and it is computationally simpler to check the criteria than to perform the model checking. The method is sound, but in general it is not complete: it may not be able to conclude that a property holds of a featured system even if it does hold. In the case of safety properties, we give an intuitive explanation of why it is likely to be complete in practice.     

Effect of the order of potassium introduction on the texture and activity of Mo/Al2O3 catalysts in water gas shift reaction

The effect of deposition and order of potassium introduction on the texture and activity of Mo/γ-Al₂O₃ catalysts in water gas shift (WGS) reaction was investigated. The samples were synthesised by incipient wetness impregnation of the carrier with aqueous solutions of the corresponding salts followed by drying and calcination after each deposition step. The prepared catalyst precursors were sulphided at 400°C for 2 h with 6% H₂S in H₂ before testing in WGS reaction in a glass flow apparatus at 400°C under atmospheric pressure.

The results show that potassium deposition alone on the bare γ-Al₂O₃ (sample K/Al₂O₃) decreases the specific surface after calcination by blocking the constrictions between the pores in the primary porous texture. In the WGS reaction conditions part of the pores are deblocked and a redistribution in the pore volumes occurs.

The deposition of the Mo (sample Mo/Al₂O₃) also results in a decrease in both specific surface and total pore volume with respect to the bare support. However after catalytic activity test no substantial changes in its texture were observed.

The addition of K to the Mo (sample KMo/Al₂O₃) leads to nonuniformity in distribution of molybdenum–oxygen entities due to partial migration of the MoO_x species to the external surface. The specific surface is not changed during the reaction test.

The deposition of Mo on K/Al₂O₃ contributes to the uniform distribution of oxomolybdenum species in the porous texture of the support. This uniformity is preserved to a high extent in the catalytic reaction as well. The activity in the synthesised samples in the WGS reaction decreases in the order MoK/Al₂O₃ > Mo/Al₂O₃ > KMo/Al₂O₃.     

Application of polyuronides for removing heavy metals from vegetable oils II. Application of chemically modified polyuronides for demetalization of hydrogenated sunflower oil

Summary The possibility of heavy metal removal from hydrogenated vegetable oils with the help of chemically modified pectins was studied. These included pectic acids of different origin, sunflower, apple and celery, crosslinked with epichlorohydrin, as well as amidated pectins with different degrees of amidation. The degree of oil demetalization obtained was high- from 78% to 94%. It was found that the removal of the heavy metals Cu, Fe, Zn and Ni depended on the type of chemical modification of the pectin. The best results were obtained with amidated pectic acid.

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Einsatz von Polyuroniden zur Entfernung von Schwermetallen aus pflanzlichen Ölen II. Einsatz von chemisch modifizierten Polyuroniden zur Entmetallisierung von hydriertem Sonnenblumenöl

Zusammenfassung Es wurde die Möglichkeit untersucht, Schwermetalle aus hydrierten pflanzlichen Ölen mit chemisch modifizierten Pectinen zu entfernen und zwar mit Epichlorhydrin vernetzten Pectinsäuren unterschiedlicher Herkunft (aus Sonnenblumenkernen, Äpfeln, Sellerie und amidierten Pectinen mit verschiedenem Amidierungsgrad). Es wurde eine hohe Entmetallisierung von 78 bis 94% erreicht. Dabei wurde festgestellt, daß die Entfernung der Schwermetalle Cu, Fe, Zn und Ni von der Art der chemischen Modifizierung des Pectins abhängig ist. Die besten Ergebnisse wurden mit amidierter Pectinsäure erzielt.

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First communication: Ivanov K, Popova M, Kratchanov C, Maneva D (1990) Z Lebensm Unters Forsch 191:210–213     

Polymerization of ethyl 2-cyanoacrylate in the presence of poly(butadiene-co-acrylonitrile)

Radical graft copolymers of ethyl 2-cyanoacrylate on to poly(butadiene-co-acrylonitrile), were prepared and characterized by infrared spectroscopy. Simultaneous homopolymerization of ethyl 2-cyanoacrylate also occurred. The polymerization of ethyl 2-cyanoacrylate is significantly affected by the presence of the pre-formed dissolved elastomer, the overall activation energies in the presence and absence of elastomer being 80.8 ± 0.4 kJ mol^?1 and 77.0 ± 0.4 kJ mol^?1, respectively. In each case the reaction was first-order with respect to the monomer.     

Solid-phase extraction of berries’ anthocyanins and evaluation of their antioxidative properties

Solid-phase extraction (SPE) was used to obtain anthocyanin-rich extracts from five berry species: chokeberry, elderberry, black currant, blackberry and blueberry. During SPE more than 94.4% of the sugars and more than 88.5% of the acids present in the crude extracts were separated. The SPE resulted in 90–95.6% anthocyanins recovery. The antioxidative properties of the anthocyanin-rich extracts were tested by measuring their oxygen radical absorption capacity (ORAC), hydroxyl radical averting capacity (HORAC), total peroxyl radical trapping antioxidant parameter (TRAP), scavenging of nitric oxide and inhibition of lipid peroxidation. Elderberry extract revealed the highest ORAC value of 5783 μmol TE/g. Chokeberry extract was the most potent inhibitor of lipid peroxidation and had the highest TRAP value of 4051 μmol TE/g. Blueberry extract had the highest HORAC result – 1293 μmol GAE/g and was the most powerful scavenger of NO. The high antioxidant activity according to all antioxidant assays revealed opportunities to apply these preparations as antioxidants.     

Methods for extracting and classifying pairs of cognates and false friends

The identification of cognates has attracted the attention of researchers working in the area of Natural Language Processing, but the identification of false friends is still an under-researched area. This paper proposes novel methods for the automatic identification of both cognates and false friends from comparable bilingual corpora. The methods are not dependent on the existence of parallel texts, and make use of only monolingual corpora and a bilingual dictionary necessary for the mapping of co-occurrence data across languages. In addition, the methods do not require that the newly discovered cognates or false friends are present in the dictionary and hence are capable of operating on out-of-vocabulary expressions. These methods are evaluated on English, French, German and Spanish corpora in order to identify English–French, English–German, English–Spanish and French–Spanish pairs of cognates or false friends. The experiments were performed in two settings: (i) assuming ‘ideal’ extraction of cognates and false friends from plain-text corpora, i.e. when the evaluation data contains only cognates and false friends, and (ii) a real-world extraction scenario where cognates and false friends have to first be identified among words found in two comparable corpora in different languages. The evaluation results show that the developed methods identify cognates and false friends with very satisfactory results for both recall and precision, with methods that incorporate background semantic knowledge, in addition to co-occurrence data obtained from the corpora, delivering the best results.     

Finding translations for low-frequency words in comparable corpora

Statistical methods to extract translational equivalents from non-parallel corpora hold the promise of ensuring the required coverage and domain customisation of lexicons as well as accelerating their compilation and maintenance. A challenge for these methods are rare, less common words and expressions, which often have low corpus frequencies. However, it is rare words such as newly introduced terminology and named entities that present the main interest for practical lexical acquisition. In this article, we study possibilities of improving the extraction of low-frequency equivalents from bilingual comparable corpora. Our work is carried out in the general framework which discovers equivalences between words of different languages using similarities between their occurrence patterns found in respective monolingual corpora. We develop a method that aims to compensate for insufficient amounts of corpus evidence on rare words: prior to measuring cross-language similarities, the method uses same-language corpus data to model co-occurrence vectors of rare words by predicting their unseen co-occurrences and smoothing rare, unreliable ones. Our experimental evaluation demonstrates that the proposed method delivers a consistent and significant improvement on the conventional approach to this task.