141. Robust and intuitive model for COVID-19 epidemic in SloveniaMatjaž Leskovar, Leon Cizelj, 2022, original scientific article Abstract: The main goal of epidemic modelling is to support the epidemic management through forecasts and analyses of past developments. With this in mind a robust and intuitive SEIR (Susceptible, Exposed, Infectious, Recovered) type model has been developed, applied and verified during the multiple waves of the COVID-19 epidemics in Slovenia since March 2020. The model parameters were based on the general characteristics of the COVID-19 disease reported globally for the entire planet and refined with the aggregate data available mostly on a daily basis in Slovenia, as for example the number of confirmed cases, hospitalized patients, hospitalized patients in intensive care units and deceased. The Slovenian aggregate data was also used to estimate the degree of immunisation due to past infections and vaccination, which reduces the number of susceptible persons for the disease. Examples of the model application are presented to illustrate its robustness and intuitiveness in both the forecasts and analyses of past developments. The analyses of past developments provided specific estimates of modelling parameters for Slovenia and quantified the effects of pharmaceutical and non-pharmaceutical interventions and various events on the development of the epidemics as measured through the reproduction number R. This empirically obtained information was then applied in the forecasts. Accurate forecasts are a great support for decision makers and for hospitals to plan appropriate actions in advance. The inherent uncertainties in the model and data were quantified through intuitive sensitivity analyses represented as different scenarios. The observed accuracy of the forecasts was impressively good also in demanding conditions, when various complex processes influencing the spread of the disease were going on in parallel. This demonstrates the robustness and relevance of the proposed model.
Keywords: epidemic, COVID-19, modelling SEIR, reproduction number
Published in DiRROS: 11.04.2025; Views: 100; Downloads: 50
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146. Towards strategic agenda for European nuclear education, training, and knowledge managementLeon Cizelj, Csilla Pesznyák, Jörg Starflinger, Gabriel Lazaro Pavel, Franck Wastin, Eirini Michailidou, 2024, original scientific article Abstract: The key elements of the EU-wide strategic agenda for nuclear education, training, and knowledge management are proposed in this paper. They were developed partly within the ENEN+ and ENEN# projects, to support and consolidate the efforts of the nuclear stakeholders to attract, develop, and retain new talents. The paper considers the projections of needs developed by the European Human Resources Observatory-Nuclear (EHRO-N). It builds on the existing national nuclear education strategies in the EU and beyond and more than two decades of experience with the European Nuclear Education Network (ENEN). The paper outlines and substantiates the most important actions and risks related to human resources, which need to be managed successfully for the EU to contribute to the tripling of the nuclear power generation capacity on the planet by 2050 (as announced in COP28) and to retain its leading role in the nuclear power and non-power applications. The sheer complexity of this challenge calls for high-level strategic support, coordination, and partnership between all nuclear stakeholders, especially those involved in the decision-making. The present situation calls for urgent strategic actions with long-term sustainability.
Keywords: nuclear education, training, knowledge management, strategic agenda
Published in DiRROS: 11.04.2025; Views: 83; Downloads: 42
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147. Fast Fourier transform approach to strain gradient crystal plasticity : regularization of strain localization and size effectAmirhossein Lame Jouybari, Samir El Shawish, Leon Cizelj, 2024, original scientific article Abstract: The Strain Gradient Crystal Plasticity (SGCP), based on cumulative shear strain, is developed to regularize and simulate the size effect behavior of polycrystalline aggregates, specifically in the formation of localization bands in terms of slip and kink bands, influenced by strain softening during the initial stages of plastic deformation. In this respect, the thermodynamically consistent derivation of the SGCP equations is presented, establishing their connection to the kinematics of classical crystal plasticity (CCP) framework. The governing balance equations are solved using the fixed-point algorithm of the fast Fourier transform (FFT)-homogenization method, involving explicit coupling between the classical and SGCP balance equations. To address this problem, a strong 21-voxel finite difference scheme is established. This scheme is considered to solve the higher order balance equation inherent to SGCP. Additionally, three types of interface conditions are implemented to explore the impact of grain boundaries on the transmission of localization bands. These conditions yield consistent intragranular/transgranular localization patterns in the MicroFree and MicroContinuity cases, while in the MicroHard condition all localization bands are intragranular with stress concentrations appearing at the grain boundaries. Analytical solutions corresponding to different material behaviors are developed and compared with numerical results to validate the numerical implementation of the FFT fixed-point algorithm. It is observed that both the macroscopic behavior and microscopic variables in CCP framework are highly influenced by grid resolutions (non-objective), leading to numerical instabilities arising from the material softening and subsequent formation of localization bands, both in single crystals and polycrystalline aggregates. Remarkably, the developed SGCP model provides results that are independent of grid resolutions (objective) and effectively regularizes the material behavior on local scale. Moreover, the non-local parameter of the model is capable of controlling the localization band widths. Finally, the proposed SGCP model, together with employed MicroHard condition on grain boundaries, is demonstrated to qualitatively reproduce main microstructural features of irradiated polycrystalline materials.
Keywords: strain localization A, strain gradient crystal plasticity B, polycrystalline material B, FFT-homogenization method C
Published in DiRROS: 11.04.2025; Views: 98; Downloads: 50
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148. Skriti dokumenti Ivana PucljaTomaž Ivešić, 2017, review article Abstract: V prispevku je predstavljenih pet najdenih dokumentov, ki jih je Ivan Pucelj skril med zapisnike Kmetijske družbe v Ljubljani. Dokumenti so nastali med drugo svetovno vojno in so izrazito politične narave. Na podlagi analize najdenega gradiva je mogoče sklepati, da se Pucelj po izstopu iz konzulte septembra 1941 politično ni povsem umaknil, prav tako pa je najverjetneje imel med visokimi krogi Slovenske ljudske stranke svojega zaupnika.
Keywords: arhivsko gradivo, osebne zapuščine, dokumenti, notranja politika, Jugoslovanska nacionalna stranka, Slovenska legija, druga svetovna vojna, 1943/1944
Published in DiRROS: 11.04.2025; Views: 52; Downloads: 19
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149. Feeding habits of the invasive ctenophore Mnemiopsis leidyi in the Gulf of Trieste (Adriatic Sea)Borut Mavrič, Danijel Ivajnšič, Davor Lučić, Alenka Malej, Lovrenc Lipej, 2025, original scientific article Abstract: The diet of the invasive ctenophore Mnemiopsis leidyi in the Gulf of Trieste was examined during its peak occurrence in the summer and early-autumn months (July to October) from 2017 to 2019, through the analysis of stomach contents. Altogether 506 specimens were individually caught for the analysis. A total of 3215 prey items were isolated and identified. Copepods emerged as the primary prey (relative abundance 66.7%), followed by cladocerans (7.7%), and bivalve larvae (6%). Notably, specimens of M. leidyi constituted a significant portion of the diet (5.4.%), providing further evidence of cannibalism within this species. Copepods were also the most commonly occurring prey items in the diet of M. leidyi. Most of them were represented by calanoid and cyclopoid nauplii (48.2%), followed by a harpacticoid M. norvegica (28.3%), and calanoids (26.8%). Other frequently occurring taxa were bivalve larvae (19.3%), M. leidyi (18.7%), and cladoceran Penilia avirostris (16.1%). The rate of cannibalism peaked in July, coinciding with a period of limited food availability. Additionally, the study revealed that fish eggs and larvae were infrequently found in the stomachs of M. leidyi. However, the presence of massive aggregations of M. leidyi may impact microzooplankton populations in late summer or autumn, potentially leading to competition with small pelagic fish.
Keywords: bioinvasion, cannibalism, comb jelly, competition, diet, Mediterranean Sea
Published in DiRROS: 10.04.2025; Views: 80; Downloads: 34
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150. Functionalization of FeCoNiCu medium entropy alloy via nitridation and anodic oxidation for enhanced oxygen evolution and glycerol oxidationLuka Suhadolnik, Milutin Smiljanić, Marjan Bele, Mejrema Nuhanović, Matjaž Finšgar, Nik Maselj, Daniela Neumüller, Lidija D. Rafailović, Nejc Hodnik, 2025, original scientific article Abstract: Medium entropy alloys (MEAs) have emerged as a promising class of materials for electro-catalysis due to their tunableproperties and exceptional catalytic performance. This study successfully functionalized a bulk FeCoNiCu alloy using a combined anodic oxidation (AO) and nitridation (NT) approach to produce a highly porous, thin-film catalyst. The hierarchical structure formed during the surface treatments enhances the material's specific surface area and alters the oxidation states of the constituent metals, creating abundant active sites. The electrocatalytic performance of themodified bulk FeCoNiCu electrode was evalu-ated for both the oxygen evolution reaction (OER) and glycerol oxidation reaction (GOR) in an alkaline electrolyte. Remarkably, the AO-NT-treated catalyst exhibited superior activity for OER, surpassing commercial IrOx benchmarks with lower overpotential requirements. For GOR, the FeCoNiCu electrode demonstrated excellent performance by significantly reducing energy input compared to OER, highlighting its potential as a dual-purpose catalyst for alkaline water splitting. Post-reaction product analysis via NMR confirmed the formation of value-added chemicals, with formic acid identified as the main product. These results underline the feasibility of surface-modified MEAs for sustainable energy and chemical production applications, offering a cost-effective alternative to noble metal-based catalysts.
Keywords: medium entropy alloy, surface modification, electrocatalysis, oxygen evolution reaction, glycerol oxidation
Published in DiRROS: 10.04.2025; Views: 106; Downloads: 67
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