The Main Obstacles and Possibilities of the Cooperative Movement in Lithuania

Abstract The article analyses the obstacles of the cooperative movement in Lithuania and proposes new insights for the development of their activities. Analysis was based on and carried out using the Delphi survey methodological approach. The experience of a transnational Association of Producers Organisation "First International Association Fruit" was investigated as a relevant example. Suggestions for the development of Lithuanian cooperatives were worked out

Enhanced optical properties of yttrium aluminum garnet with the yttrium vanadate impurity phase

Yttrium aluminum garnet doped with europium with an additional impurity phase of yttrium vanadate doped europium has been prepared in different ways: synthesized by a sol-gel route and mechanically mixed in a mortar. The obtained samples were characterized by X-ray diffraction analysis, and scanning electron microscopy. Photoluminescence spectra were recorded to understand the role of the impurity phase in the garnet's optical properties. The impurity phase showed a significant contribution to the optical properties of Y3Al5O12:1%Eu. --//-- Monika Skruodiene, Ruta Juodvalkyte, Meldra Kemere, Rimantas Ramanauskas, Anatolijs Sarakovskis, Ramunas Skaudzius, Enhanced optical properties of yttrium aluminum garnet with the yttrium vanadate impurity phase, Heliyon, Volume 8, Issue 11, 2022, e11386, ISSN 2405-8440, https://doi.org/10.1016/j.heliyon.2022.e11386. (https://www.sciencedirect.com/science/article/pii/S2405844022026743). Published under the CC BY-NC-ND licence.ERDF [1.1.1.2/VIAA/3/19/480]; the Institute of Solid State Physics, University of Latvia (Latvia), as the Centre of Excellence has received funding from the European Union’s Horizon 2020 Frame-work Programme H2020-WIDESPREAD-01-2016-2017-Teaming Phase2 under grant agreement No. 739508, project CAMART

Sol-gel assisted molten-salt synthesis of novel single phase Y3–2xCa2xTaxAl5−xO12:1%Eu garnet structure phosphors

Strong absorption and emission are the key the features of any phosphor. The results obtained during this study demonstrate the difficulty of the incorporation of tantalum ions into the garnet structure and reveal that only the combination of Sol-Gel synthesis method together with Molten-Salt technique enable to obtain a single-phase cubic garnet structure. Note that, the Sol-Gel synthesis assisted by further processing by Molten-Salt technique can be a potentially new way of material preparation reported in literature. This work also proves that this combination of synthesis methods is much more capable of incorporating ions with large ionic radii into the garnet structure as compared to traditional Sol-Gel method. Moreover, samples synthesized using this new technique exhibit 30% higher emission intensities as compared to the ones prepared by the original Sol-Gel method, while also reducing the needed sintering temperature by 200 °C. To the best of our knowledge, the modification of yttrium aluminum garnet (Y3Al5O12, YAG) by co-doping it with Ca2+ and Ta5+ ions by Sol-Gel assisted Molten-Salt route has been investigated for the first time. --//-- Monika Skruodiene, Ruta Juodvalkyte, Greta Inkrataite, Andrius Pakalniskis, Rimantas Ramanauskas, Anatolijs Sarakovskis, Ramunas Skaudzius, Sol-gel assisted molten-salt synthesis of novel single phase Y3–2xCa2xTaxAl5−xO12:1%Eu garnet structure phosphors, Journal of Alloys and Compounds, Volume 890, 2022, 161889, ISSN 0925-8388, https://doi.org/10.1016/j.jallcom.2021.161889. Article published under the CC BY license.The work of Monika Skruodiene is supported by ERDF PostDoc project No. 1.1.1.2/VIAA/3/19/480. Institute of Solid State Physics, University of Latvia has received funding from the European Union's Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2

Genetic Algorithm with Modified Crossover for Grillage Optimization

Modified genetic algorithm with special phenotypes' selection and crossover operators with default specified rules is proposed in this paper thus refusing the random crossover. The suggested crossover operator enables wide distribution of genes of the best phenotypes over the whole population. During selection and crossover, the best phenotypes of the newest population and additionally the genes of the best individuals of two previous populations are involved. The effectiveness of the modified algorithm is shown numerically on the real-life global optimization problem from civil engineering - the optimal pile placement problem under grillage-type foundations. This problem is a fair indicator for global optimization algorithms since the ideal solutions are known in advance but with unknown magnitudes of design parameters. Comparison of the proposed algorithm with 6 other stochastic optimization algorithms clearly reveals its advantages: at similar accuracy level the algorithm requires less time for tuning of genetic parameters and provides narrower confidence intervals on the results than other algorithms

Temperature-Induced Structural Transformations in Undoped and Eu3+-Doped Ruddlesden–Popper Phases Sr2SnO4 and Sr3Sn2O7: Relation to the Impedance and Luminescence Behaviors

We report that luminescence of Eu3+ ion incorporated into Ruddlesden–Popper phases allows monitoring phase transition in powders (instead of single crystals), in a time-efficient manner (compared to neutron diffraction), and importantly, with greater sensitivity than previous methods. Crystal structure and dielectric response of undoped and 0.5%Eu3+-doped Sr3Sn2O7 ceramics were studied as a function of temperature over the temperature range of 300–800 K. The luminescence studies of 0.5%Eu3+-doped Sr2SnO4 and Sr3Sn2O7 samples were performed in the temperature range of 80–500 K. These results were compared with the respective dependences for the undoped compounds. The structural transformations in 0.5%Eu3+-doped Sr3Sn2O7 were found at 390 and 740 K. The former is associated with the isostructural atomic rearrangement that resulted in a negative thermal expansion along two of three orthorhombic crystallographic axes, while the latter corresponds to the structural transition from the orthorhombic Amam phase to the tetragonal I4/mmm one. A similar temperature behavior with the structural transformations in the same temperature ranges was observed in undoped Sr3Sn2O7, although the values of lattice parameters of the Eu3+-doped and undoped compounds were found to be slightly different indicating an incorporation of europium in the crystal lattice. A dielectric anomaly associated with a structural phase transition was observed in Sr3Sn2O7 at 390 K. Optical measurements performed over a wide temperature range demonstrated a clear correlation between structural transformations in Eu3+-doped Sr2SnO4 and Sr3Sn2O7 and the temperature anomalies of their luminescence spectra, suggesting the efficacy of this method for the determination of subtle phase transformations

Sol-gel derived coatings for the conservation of steel

In this paper, sol-gel processing route has been applied and investigated for the conservation of steel. Nanosilica coatings on steel surface have been prepared using tetraethylorthosilicate (TEOS) as a starting material. The methyl-modified silica sols were obtained by mixing of 3 mas.% SiO2 sol solution with hexamethyldisilozane (HMDS). The surface of steel was coated by dip-coating technique. In order to compare the characteristics of coatings, the steel substrates were also coated with commercial polymers Paraloid B67, Cosmolloid H80 and Antik Patina. The surface morphology changes of the uncoated and coated specimens before and after photochemical ageing were investigated by scanning electron microscopy and atomic force microscopy. The structure of the prepared coatings was also investigated by FTIR spectroscopy. The hydrophobicity of surfaces was evaluated by contact angle measurements. Potentiodynamic measurements were obtained in order to compare corrosion parameters of the coatings

Zespołowe użytkowanie maszyn jako forma przedsiębiorczości

ISM Vadybos ir ekonomikos universitetasKlaipėdos universitetasVytauto Didžiojo universitetasŽemės ūkio akademij