Chitin deacetylase is the only known enzyme which is able to deacetylate N-acetyl-D-glucosamine units in chitin or chitosan chains. As chitin can hardly be dissolved in organic/inorganic solvents, new solvents are still searched. Ionic liquids are promising for that application and for homophase enzymatic deacetylation. The aim of the work was to investigate the influence of selected ionic liquids on activity of chitin deacetylase.
It has been shown that [Amim] ionic liquids increase the activity of chitin deacetylase. The highest activity was observed for [Amim][Cl]. Ionic liquids with shorter (ethyl (C2)) and longer side chain (buthyl (C4)) only insignificantly influenced the activity of the enzyme. All tested ionic liquids with [Br] anion increased the activity of chitin deacetylase while the [Emim] and [Bmim] cation in combination with [Cl] anion inhibited the activity of the enzyme.
The results of statistical analysis applied in order to evaluate the effect of the high melting point elements to pressure die cast silumin on its tensile strength Rm, unit elongation A and HB were discussed. The base alloy was silumin with the chemical composition similar to ENAC 46000. To this silumin, high melting point elements such as Cr, Mo, V and W were added. All possible combinations of the additives were used. The content of individual high melting point additives ranged from 0.05 to 0.50%. The tests were carried out on silumin with and without above mentioned elements. The values of Rm, A and HB were determined for all the examined chemical compositions of the silumin. The conducted statistical analysis showed that each of the examined high melting point additives added to the silumin in an appropriate amount could raise the values of Rm, A and HB. To obtain the high tensile strength of Rm = 291 MPa in the tested silumin, the best content of each of the additives should be in the range of 0.05-0.10%. To obtain the highest possible elongation A of about 6.0%, the best content of the additives should be as follows: chromium in the range of 0.05-0.15%, molybdenum 0.05% or 0.15%, vanadium 0.05% and tungsten 0.15%. To obtain the silumin with hardness of 117 HB, chromium, molybdenum and vanadium content should be equal to about 0.05%, and tungsten to about 0.5%.
The analysis of the current state of weather and climatic conditions and evaluation of their predicted changes for im-mediate and distant prospect in the drained areas of Ukrainian Polissia region was carried out in the article. The main trendsin changes of meteorological characteristics and their possible effect on the conditions of functioning water management and ameliorative objects and complexes as well as on the natural and ameliorative state of drained areas were identified. The research uses a method of predictive-simulation modelling with used predictive assessment models of normalized dis-tribution of the basic meteorological characteristics in the long-term and one-year vegetation context. According to the re-sults of the research it was established that, for today a high variability in meteorological characteristics can lead to the sig-nificant deterioration of operation conditions of water management and ameliorative objects and units, as well as natural and ameliorative conditions of drained lands in Polissia region as a whole. Core measures regarding the adaptive potential enhancement and development in the region under the conditions of climate change were examined.
The series of experiments was performed on commercial polymeric composite material MultimetalStahl 1018. Strength tests were performed to determine the yield point of the material. The composite had the highest hardness at a temperature of 20°C. Hardness and microhardness were determined in further experiments. The adhesiveness of the material to metal surfaces and impact strength were also analyzed. The scanning electron microscopy and X-ray microanalysis methods were used for analyzing the microstructure of the material. Chemical composition of selected areas was analyzed, which allowed for a preliminary identification of metallic elements content in the composite. The microstructure of composite is highly non-homogeneous and particular phases are highly elongated and angular. The analyzed phase was enriched with silicon, aluminium, magnesium, iron and vanadium other phases enriched with metallic elements, e.g. molybdenum, titanium, vanadium and also oxygen as well as traces of cadmium and chromium. The results were presented in the form of photos and illustrations. The results confirmed the applicability of the composite as a binder for fixing mechanical and foundry devices.