Quenched steel welding

The aim of this research was to develop a process for welding BORON 27 type quenched steel, manufactured in Finland. The composition of a shielding gas mixture was selected by means of trials: 90% Ar, 5% CO₂, and 5% O₂. Joints were reproduced by this method, i.e. welded, quenched joints as well as unquenched welded joints, and were tested for quality. Tests included X-ray radiography, macroscopic testing, hardness tests, and tearing and bending resistance tests. The results of these tests were presented in the article.     

New Opportunities of the Application of Natural Herb and Spice Extracts in Plant Oils: Application of Electron Paramagnetic Resonance in Examining the Oxidative Stability

The aim of this study was to establish the applicability of natural water-ethanol extracts of herbs and spices in increasing the oxidative stability of plant oils and in the production of novel food. Different concentrations (0, 100, 300, 500, and 700 ppm) of spice extracts and butylated hydroxyanisole (BHA) (100 ppm) were added to the studied oils. The antioxidant activity of spice extracts was determined with electron paramagnetic resonance (EPR) spectroscopy using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay. The study showed that the extracts significantly increased the oxidative stability of the examined oils when compared to one of the strongest synthetic antioxidants-BHA. The applied simple production technology and addition of herb and spice extracts to plant oils enabled enhancement of their oxidative stability. The extracts are an alternative to the oils aromatized with an addition of fresh herbs, spices, and vegetables because it did not generate additional flavors thus enabling the maintenance of the characteristic ones. Moreover, it will increase the intake of natural substances in human diet, which are known to possess anticarcinogenic properties.     

Microstructured Reactor as a Pre-Turbo Catalytic Converter

The idea of a structured catalytic converter placed immediately after engine exhaust valves, thus operating on high gas temperature and velocity, is explored. The assumption is that major part of the reactor operates in the entry region where Nusselt and Sherwood numbers are highly enhanced. In this work, flow resistances as well as heat and mass transfer coefficients were studied for gas velocities exceeding 50 m/s. Consequently, the transition range (between laminar and turbulent flows) was reached. The comparison with classic monolith has shown significant improvement in heat or mass transfer paid by slight increase in flow resistance.     

Renewable energy in the Kujawsko-Pomorskie Voivodeship (Poland)

In this article we presented the current state and prospects for development of renewable energy in the Kujawsko-Pomorskie Voivodeship, in which the greatest amount of renewable energy in Poland is obtained. In this area there are 96 wind power plants, 103 water power plants, 7 biogas power plants, 4 biofuel producing plants, 3 big energy willow (Salix viminalis) plantations as well as numerous biomass boilers (mostly using wood). In the near future it is planned to further develop renewable energy based on wind, water and biomass.     

Eu(III)-coupled luminescent multi-walled carbon nanotubes in surfactant solutions

A carbon nanotube/inorganic hybrid material has been fabricated by coupling Eu(III) complexes onto multi-walled carbon nanotubes (MWCNTs). Successful coupling has been verified by X-ray photoelectron spectroscopy (XPS) measurement where a clear signal from Eu3d has been identified. When sonicated in hexaethylene glycol monododecyl ether (C₁₂E₆) or sodium dodecyl sulfate (SDS) aqueous solutions, the MWCNTs with Eu-complex attached (denoted as Eu-MWCNTs hereafter) can be dispersed. UV–vis measurements on a dilute dispersion of Eu-MWCNTs in SDS aqueous solution reveal the characteristic absorption from Eu(III) complexes, which gives further proof of the successful coupling. The strong luminescent properties of Eu-MWCNTs allow them to be observed directly under a fluorescence microscope. Interestingly, it is found that Eu-MWCNTs can undergo continuous movements in C₁₂E₆ or SDS dilute solutions. When Eu-MWCNTs are incorporated into the lyotropic liquid crystal phase formed by C₁₂E₆ (above 40% by weight), however, movements have been hindered. Small angle X-ray scattering measurements showed that Eu-MWCNTs are ordered in the lyotropic liquid crystal. Fluorescence microscopy observations reveal that the luminescent properties of the Eu-MWCNTs have not been affected by the liquid crystalline surfactant matrix.     

Development of Oxide Scale at 1,100 °C on Fe20Cr5Al Alloy Non-Implanted and Yttrium-Implanted

The development of the oxide scale on model Fe20Cr5Al-type alloys unmodified and containing implanted yttrium was studied in oxygen-dominated atmosphere at 1,100 °C for up to 1 h. A two-stage-oxidation exposure was applied with the use of ¹⁸O₂ as a tracer. The choice of the exposure durations ensured the possibility to follow the consecutive stages of scale development. The oxidized samples were characterized using SEM (morphology); PLS (phase composition), and SIMS (elemental distributions). The obtained results are discussed in terms of the mechanism of the development of protective α-Al₂O₃ scale and the effect of the additions on this process taking into account the necessity of distinguishing the mechanism and kinetics of the scale evolution. Similar scale evolution stages were found on both studied materials and in both cases the protective α-Al₂O₃ scale developed rapidly, already after the exposure for 3 min. Implanted yttrium appeared to have a negligible effect on the evolution of the scale. It only slightly retarded the evolution which can be attributed rather to a kinetic effect than to mechanistic one. However, the mechanical failure of the scales via formation of cracks at the asperities of convolutions occurred on the yttrium-implanted alloy but not on the non-implanted one.     

Fatty acid profile of hind leg muscle in female and male nutria (Myocastor coypus Mol.), fed green forage diet

The study describes the profile of fatty acids in hind leg muscle of 18 female and 12 male nutria reared on an extensive system farm in eastern Poland with a diet based on fresh forage. When compared to results from nutrias from an intensive production system from the literature, the forage-fed animals had lower proportions of saturated fatty acids, and higher proportions of n3-fatty acids in their muscle tissue; in particular, n6:n3-fatty acid ratios were lower (2.6–3.0) in forage-fed animals compared to intensively reared animals (16.8–28.9). These findings underline that using forage-based diets is feasible in nutrias, and an economic way to improve the fatty acid composition of their meat.     

Formation of RNA Phosphodiester Bond by Histidine‐Containing Dipeptides

A new scenario for prebiotic formation of nucleic acid oligomers is presented. Peptide catalysis is applied to achieve condensation of activated RNA monomers into short RNA chains. As catalysts, L ‐dipeptides containing a histidine residue, primarily Ser‐His, were used. Reactions were carried out in selforganised environment, a water‐ice eutectic phase, with low concentrations of reactants. Incubation periods up to 30 days resulted in the formation of short oligomers of RNA. During the oligomerisation, an active intermediate (dipeptide–mononucleotide) is produced, which is the reactive species. Details of the mechanism and kinetics, which were elucidated with a set of control experiments, further establish that the imidazole side chain of a histidine at the carboxyl end of the dipeptide plays a crucial role in the catalysis. These results suggest that this oligomerisation catalysis occurs by a transamination mechanism. Because peptides are much more likely products of spontaneous condensation than nucleotide chains, their potential as catalysts for the formation of RNA is interesting from the origin‐of‐life perspective. Finally, the formation of the dipeptide–mononucleotide intermediate and its significance for catalysis might also be viewed as the tell‐tale signs of a new example of organocatalysis.