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  • Author: E. Kamińska x
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J. Kamińska, M. Angrecki, A. Palma, J. Jakubski and E. Wildhirt

Abstract

The results of own studies concerning the application of a new additive to the CO2-hardened sodium water glass foundry sands are presented. The new additive, which is a composition of aqueous solutions of modified polyalcohols, has been designated by the symbol “B” and is used as an agent improving the sand knocking out properties. The scope of studies included various mechanical and technological properties of foundry sand mixtures, such as permeability, friability, life cycle of cores and knocking out properties. Two types of water glass with different values of the silica modulus and density, designated as R145 and R150, were tested. Moulding sands used in the tests were made with the additive “B”. For comparison, a reference sand mixture with water glass but without the additive “B” was also prepared.

Open access

S. Księzarek, M. Woch, D. Kołacz, M. Kamińska, P. Borkowski and E. Walczuk

Abstract

The paper outlines technologies currently used for the production of the Ag-Re10 and Ag-SnO2Bi2O3 contact materials in a form of wires and solid and bimetallic rivets. Their characteristic parameters, including physical and mechanical properties and microstructure, are given. It has been found that the level of these parameters, particularly electrical properties (resistance to electric arc erosion), is unsatisfactory considering the present requirements, which applies mainly to the new Ag-Re10 [wt%] alloy, so far not fully technologically mastered. Therefore, under this work a new method for the production of this type of materials has been designed and the related research works were undertaken. The new-generation contact materials in a form of nanostructured composites will be characterised by similar chemical compositions as those specified above but with increased functional properties, including enhanced resistance to arc erosion. In this paper preliminary results of the examination of structure and properties of semi-products obtained by new technology based on powder metallurgy techniques are presented. Conditions for pressure consolidation and plastic consolidation applied for material processing into wires and rivets (solid and bimetallic) have been determined.

Open access

Artur Jóźwik, Ewa Polawska, Nina Strzałkowska, Krzysztof Niemczuk, Małgorzata Łysek-Gładysińska, Agnieszka Kamińska and Monika Michalczuk

Abstract

The aim of the study was to assess the activity of lysosomal enzymes: aminopeptidases, including alanine aminopeptidase (AlaAP), leucine aminopeptidase (LeuAP), arginine aminopeptidase (ArgAP), and glycosidases, such as β-galactosidase (BGAL), β-glucuronidase (BGRD), β-glucosidase (BGLU), N-acetyl-β-hexosaminidase (HEX), α-glucosidase (AGLU) and α-mannosidase (MAN) in the liver of ostriches (n = 80) fed diet supplemented with linseed (4% and 8%) and rapeseed (5% and 10%), with low and high level of vitamin E. (40 and 100 mg). The results indicate that higher level of vitamin E or 4% linseed supplementation in ostrich diet generally increase the activity of glycosidase enzymes and decrease the activity of aminopeptidases in the liver. The 8% linseed and rapeseeds feeding in decreased the activity of AlaAP, LeuAP, and ArgAP and increased only the activity of BGLU.

Open access

A. Taube, M. Guziewicz, K. Kosiel, K. Gołaszewska-Malec, K. Król, R. Kruszka, E. Kamińska and A. Piotrowska

Abstract

The paper presents the results of characterization of MOS structures with aluminum oxide layer deposited by ALD method on silicon carbide substrates. The effect of the application of thin SiO2 buffer layer on the electrical properties of the MOS structures with Al2O3 layer has been examined. Critical electric field values at the level of 7.5–8 MV/cm were obtained. The use of 5 nm thick SiO2 buffer layer caused a decrease in the leakage current of the gate by more than two decade of magnitude. Evaluated density of trap states near the conduction band of silicon carbide in Al2O3/4H-SiC MOS is about of 1×1013 eV−1cm−2. In contrast, the density of the trap states in the Al2O3/SiO2/4H-SiC structure is lower about of one decade of magnitude i.e. 1×1012 eV−1cm−2. A remarkable change in the MOS structure is also a decrease of density of electron traps located deeply in the 4H-SiC conduction band below detection limit due to using of the SiO2 buffer layer.