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The results of the present investigation are focused on the structure examinations of a commercial Al-3%Mg alloy in different conditions using an optical microscope (OM), scanning electron microscopy (SEM), the EBSD technique, transmission electron microscopy (TEM) and X-ray diffraction (XRD). Measurements of the microhardness and ultimate tensile strength were carried out to evaluate the influence of ECAP and post-ECAP treatment on the mechanical properties. In this study, we found that 6 ECAP passes via route B c result in a significant grain refinement. The measured average grain size of the as deformed sample was about 0.43 μm. As a result of the performed post-ECAP heat treatment (artificial ageing), a material with a more homogenous microstructure, having an average grain size of ~ 0.68 μm, was obtained. The results of the mechanical property measurements show a significant increase in mechanical strength to about ~ 384 [MPa] in the T9 condition and to ~ 330 [MPa] after post-ECAP treatment (T8 condition). The high strength of the alloy in the T9 condition is suggested to be related to grain size strengthening, dislocation strengthening and precipitation strengthening. An increase in elongation/ductility from 2.4% to 11.2% was observed in the T8 condition sample, which is a result of the grain growth and the dislocation density decrease. [ABSTRACT FROM AUTHOR]

Abstract The comprehensive study of the Ni 0.5 Zn 0.5 Fe 2 O 4 ferrite nanopowder crystallized in the inverse spinel structure and synthesized by co-precipitation method is presented. The distribution of Fe3+ cations among tetrahedral and octahedral sites was confirmed. The microstructural investigations revealed the presence of ultrafine grained structure with an average crystallites size in the range of 14 ÷ 20 nm. Raman and Fourier-Transform Infrared (FTIR) spectroscopy studies confirmed typical spinel structure with tetrahedrally and octahedrally iron occupancy as well as indicate co-associated iron-oxide phases considered as factors responsible for the structural disorder. The magnetic properties revealed the superparamagnetic behavior at the room temperature with estimated critical size of single domain particles about 63 nm. The analysis of saturation magnetization pointed to the spin canting phenomenon in the surface layer. The valuation of exchange coupling parameters based on the mean field theory calculation strengthened the conclusion about opposite magnetization arrangement between tetrahedral and octahedral magnetic sublattices. Graphical abstract Image 1 Highlights • Co-precipitated Ni 0.5 Zn 0.5 Fe 2 O 4 nanoferrite addopt the cubic inverse spinel ferrite structure. • The average nanocrystallites/nanoparticles size estimated by TEM is about 15 nm. • Fe3+ cations are distributed at A – tetrahedral and B – octahedral sites. • Studied nanoferrite reveals the superparamagnetic nature at the room temperature. • The canting spin effect was confirmed based on magnetic measurements. [ABSTRACT FROM AUTHOR]

Although regular physical activity is known to benefit health of aging populations, there are still many factors, which regulate exercise-induced adaptive changes. Among many vitamin D and myokines are under consideration. We, therefore, evaluated the influence of a single session of and regular Nordic Walking (NW) training combined with vitamin D supplementation on cognitive functions and muscle strength and some elements of the amino-acid profile. Thirty-five healthy elderly women (68 ± 5 years old) from health promotion programmes took part in the study. At baseline they were divided into two groups: women, who participated in NW training for the first time (Beginners Group: BG) and women, who continued regular NW training longer than four years (Advance Group: AG). All women had a similar concentration of vitamin D (above 20 ng·ml −1 ) at baseline. The 12 weeks of NW training was supported by supplementation of vitamin D 3 (4000 IU/day). Muscle strength, serum concentrations of myokines (irisin and IL-6), brain derived neurotrophic factor (BDNF), inflammation marker, glucose, branched amino acids and tryptophan were all assessed at baseline, 1 h after the first single training session and adequately at the end of the training programme. In addition, iron and ferritin were measured. The concentration of vitamin D 3 as well as psychological (Quality-of-Life Assessment, The Beck Depression Inventory-2) and cognitive evaluations (D2 test of attention, Trial Making Test A&B) were also performed before and after the 12-week training programme. Data were interpreted using magnitude-based inferences. According to data obtained in this study, regular NW training resulted in improvement of cognitive functions in aged women. These positive changes were accompanied by an increase of irisin and BDNF concentration (adjusted effect moderate and likely). Our data also revealed that observed reductions of glucose and tryptophan concentrations might have positively contributed to the amelioration of cognitive functions. Still, obtained results indicated that it was not the level vitamin D that modulated exercise-induced changes, but rather the long-lasting experience and being more advanced in training. [ABSTRACT FROM AUTHOR]

The paper refers to hard magnetic properties of (Fe 86− x Nb x B 14 ) 0.88 Tb 0.12 bulk nanocrystalline magnets prepared using the vacuum mold suction technique. A combination of a specific chemical composition and sample preparation technology leads to a formation of dendrite grains of Tb 2 Fe 14 B hard magnetic phase. The microstructure of the obtained alloys strongly depends on both these factors. The examined alloys reveal high and ultra-high coercivity exceeding 7 T at room temperature. It was shown that the observed magnetic hardening is caused by the shape of the dendrite grains with sub-micro branches as a source of additional exchange anisotropy. Favorable hard magnetic properties occur for the alloy with 6 at.% of Nb content which corresponds to the maximum of activation enthalpy of Fe crystallization in amorphous Fe 86− x Nb x B 14 basic alloys. [ABSTRACT FROM AUTHOR]