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In this paper we report results of structural, spectroscopic, and magnetic investigations of MgFe2O4 nanoparticles prepared by soft mechanochemical synthesis. MgFe2O4 nanoparticles crystallize in Fd3¯m space group with mixed cation distribution and reduced percentage of Fe3+ at tetrahedral (8a) sites. Discrepancy in the cation distribution compared to that in the bulk Mg–ferrite is one of the highest known. X-ray line broadening analysis reveals crystallite size and strain anisotropy. The saturation magnetization, Msat=62 emu/g measured at 5 K is twice higher than that found in the bulk counterparts. Such high value of Msat is attributed to the low value of cation inversion parameter (δ=0.69), to the core/shell structure of the nanoparticles and to the surface/volume ratio. Mössbauer spectrum collected at room temperature reveals ferrimagnetic ordering between Fe3+ ions in 8a and 16d sites, while zero-field-cooled (ZFC) and field-cooled (FC) M(T) measurements were shown superparamagnetic state above 350 K.

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This paper gives the results of the electricity generated by the fixed, one-axis and dual-axis tracking PV solar plant of 1 MW with flat PV panels made of monocrystalline silicon which is to be built in the area of Soko banja (spa in Serbia). Further on follows a description of the functioning of the fixed and one-axis and dual-axis tracking PV solar plant. For the calculation of the electricity generated by these plants PVGIS program from the Internet was used. Calculations have shown that fixed PV solar plant power of 1 MW, solar modules of monocrystalline silicon yield 1130000 kWh power output, one-axis tracking PV solar plant yields 1420000 kWh, and dual-axis tracking PV solar plant yields 1450000 kWh of electricity. Electricity generated by the fixed PV solar plant could satisfy 86% of the annual needs for the electricity of the „Zdravljak“ hotel and the special „Novi stacionar“ hospital in Soko banja

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We present a study of the structural and magnetic properties of (Mn,Fe) 3-d O 4 nanoparticles synthesized by soft mechanochemistry using Mn(OH) 2 Â 2 H 2 O and Fe(OH) 3 powders as starting compounds. The resulting nanoparticles with a composition of the (Mn,Fe) 3-d O 4 type are found to have a core/shell structure with different Mn/Fe ratios in the core and at the surface. XPS analysis points to valences of þ2, þ3, and þ4 for Mn and þ3 for Fe at the particle surface. Combined results of XRPD, Mössbauer spectroscopy, and EDX analysis suggest that there is a deviation from stoichiometry in the nanoparticle core compared to the shell, accompanied by creation of cation polyvalence and vacancies. The value of saturation magnetization, M S , of 73.5 emu/g at room temperature, is among the highest reported so far among nanocrystalline ferrite systems of similar composition. V C 2012 American Institute of Physics. [http://dx.

The Sokobanja basin is an area in Eastern Serbia with diverse geological and geomorphological features. Also, it is an area with developed spa tourism. The Sokobanja basin has numerous geoheritage features, which tourist potential has not been discovered yet. In this article, several geosites were analyzed, which present significant geoheritage formations. Geosites were selected by authors of this article based on the degree of their attractiveness for the geotourism development. The main goal of this article is to emphasize the geotourism potential of the Sokobanja basin and to determine the current state and geotourism potential of evaluated geosites by applying the modified geosite assessment model (M-GAM). A total of seven geosites were evaluated throughout the basin. The values of the investigated parameters were entered into the matrix of the M-GAM based on the number of points. Based on the research and the results obtained, it can be concluded that the Sokobanja basin has the potential for the development of geotourism, but it is necessary to improve additional values to become a true geotourism destination.

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