With the goals of protecting boiler tubes from hostile surroundings, increasing thermal efficiency, and minimizing time losses from damage, thermal-spray coating methods for high-temperature ...operations were created. Ceramic-metal composite materials (e.g., Cr3C2-NiCr) are well known for protecting components from erosion decay in a high-temperature environment. In this investigation, the high-velocity oxy-fuel (HVOF) thermal-spray technique was employed to successfully deposit several variations of feedstocks containing Cr3C2-NiCr and NiCr powders onto a medium-carbon steel substrate, with and without filtering through a 400-mesh screen. Utilizing X-ray fluorescence (XRF), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), the microstructure features of the deposited coatings were assessed. The experiment results demonstrate that the crystallite and grain sizes of the deposited coatings can be increased by reducing the powder size through a sifting process using a 400-mesh sieve. This procedure also resulted in a coating with a higher density and lower porosity. Furthermore, new compounds including Cr2O3 and MnCr2O4 were formed in the coating layers as indicated by the XRD spectra. These phenomena are in good agreement with the EDS mapping of Cr and O, which reveals highly similar distributions. Manganese was originally a part of the substrate composition. Manganese could diffuse rapidly across the Cr2O3 layer and form the MnCr2O4 compound, indicating the manganese diffusion from the substrate into the Cr3C2-NiCr coating. The formation of MnCr2O4 can be attributed to the prior emergence of the Cr2O3 compound.
Fibre-metal laminates (FMLs) are a multi-layered prominent class of hybrid composites gaining keen attention among researchers due to the combined advantages of the products used for aerospace and ...lightweight applications. This work involves one such investigation of hybrid sandwich laminate composites of aluminium sheets and a glass-fibre-reinforced thermoplastic (GFRP) core. FRPs can be conjoined with other lightweight materials to enhance the weight-to-strength forming performance and reduce manufacturing costs. However, the thickness reduction of the components for lightweight products makes the FRP-to-metal amalgamation a great challenge. The process of warm embossing is imposed to enhance the quality of single-lap adhesive bonding in FRPs and AA 6061 thin sheets. In this investigation, the formability of a FML made of AA 6061 and GFRP is predicted based on its deformation and wrinkle formation when it is processed during deep drawing. This research paper deals with analytical and experimental results regarding the prediction of deformation cause and effect in fabricated composite laminates with orientation angles of (90°; 0°; 60°; 30°; –45°; 45°). The method of evaluation combines the usage of ANSYS PrepPost with an explicit-dynamics module that bolsters designing, drafting and analysis.
Slovene press has recently expressed concern for the health of children who ingest playground sand contaminated with lead. However, current assessments may be overestimating the health risk, as they ...assume that human body absorbs the whole amount of a contaminant. The aim of our study was to see how much lead in sand intended for playground sandboxes in Slovenia really is absorbed and what health risk it may present. To do that, we ran bioaccessibility tests to simulate metabolism and see how digestion affects lead levels. Our results show low bioaccessibility of lead from sand (0.01- 36.84 %). Taking into account lead bioaccessibility, we ran several scenarios of sand ingestion in children and established that in general the risk is negligible, except for pica behaviour with extremely high (20 g) ingestion of sand with highly mobilised lead (2.69 μg g-1). Further research should assess real-life exposure to lead from playground sand in children and perhaps update these preliminary bioaccessibility data.
V zadnjem obdobju so se v Sloveniji pojavili številni pomisleki o varnosti mivke, ki je namenjena za otroške peskovnike. Ocena tveganja otrok, ki so izpostavljeni svincu temelji na predpostavki, da je celotna količina toksične kovine biološko dostopna. Zato je bil namen raziskave analizirati biološko dostopnost svinca v mivki, ki je namenjen za peskovnike otroških igrišč. Z simulacijo prebavnega trakta smo analizirali vpliv prebavnih sokov za izplavljanje svinca iz mivke. Rezultati kažejo na majhno biodostopnost svinca v mivki (0,01-36,84 %) slovenskih proizvajalcev. Na podlagi biološke dostopnosti smo simulirali različne scenarije vnosa in ugotovili, da je tveganje zanemarljivo, razen v primeru pica sindroma (zaužitje 20 g mivke) ter ob predpostavki največje dokazane biološke dostopnosti (2,69 μg g-1). Raziskave v prihodnosti bodo vključevale realno izpostavljenost otrok svincu iz peskovnikov in bodo morda nadgradile preliminarno raziskavo.
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