51. Electrified dynamically responsive ammonia decomposition to hydrogen based on magnetic heating of a Ru nanocatalystŽiga Ponikvar, Anja Sedminek, Janvit Teržan, Luka Skubic, Žan Lavrič, Matej Huš, Miha Grilc, Blaž Likozar, Darko Makovec, Sašo Gyergyek, 2024, original scientific article Abstract: Storing and transporting pressurized or liquid hydrogen is expensive and hazardous. As a result, safer methods, such as chemical storage in ammonia, are becoming increasingly important. However, the instantaneous start of a conventionally heated decomposition reactor is challenging. Here we report on the electrified and dynamically responsive decomposition of ammonia as a means of releasing on-demand chemically bonded hydrogen based on the rapid magnetic heating of a well-designed Ru-based nanocomposite catalyst. Under relatively mild conditions (400 °C, 1 bar) a rapid decomposition rate of 5.33 molNH3 gRu-1 h-1 was achieved. Experimental observations under non-isothermal, dynamic conditions coupled with modelling at the level of density functional theory and micro-kinetic modeling confirmed the minute-scale response of the H2 release. The rapid response of our catalytic system would, at least in principle, enable the utilization of intermittent, renewable electricity and a tunable H2/NH3 ratio in the reactor’s effluent.
Published in DiRROS: 25.03.2025; Views: 120; Downloads: 30
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52. Refined radial basis function-generated finite difference analysis of non-Newtonian natural convectionMiha Rot, Gregor Kosec, 2025, original scientific article Abstract: In this paper, we present a refined radial basis function-generated finite difference solution for a non-Newtonian fluid in a closed differentially heated cavity. The non-Newtonian behavior is modeled with the Ostwald–de Waele power law and the buoyancy with the Boussinesq approximation. The problem domain is discretized with scattered nodes without any requirement for a topological relation between them. This allows a trivial generalization of the solution procedure to complex irregular three dimensional (3D) domains, which is also demonstrated by solving the problem in a two dimensional (2D) and 3D geometry mimicking a porous filter. The results in 2D are compared with two reference solutions that use the finite volume method in a conjunction with two different stabilization techniques, where we achieved good agreement with the reference data. The refinement is implemented on top of a dedicated meshless node positioning algorithm using piecewise linear node density function that ensures sufficient node density in the center of the domain while maximizing the node density in a boundary layer where the most intense dynamic is expected. The results show that with a refined approach, more than five times fewer nodes are required to obtain the results with the same accuracy compared to the regular discretization. The paper also discusses the convergence with refined discretization for different scenarios for up to nodes, the impact of method parameters, the behavior of the flow in the boundary layer, the behavior of the viscosity, and the geometric flexibility of the proposed solution procedure.
Published in DiRROS: 25.03.2025; Views: 137; Downloads: 42
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54. A family of C1 Clough-Tocher spline spaces on C0 piecewise quadratic domain partitionsJan Grošelj, Marjetka Knez, 2025, original scientific article Abstract: The paper addresses the construction of C1 splines on a curved domain that is parametrized by a C0 piecewise geometry mapping composed of quadratic Bézier triangles. The C1 splines are assembled from polynomials of a chosen total degree greater than or equal to four, and their construction is based on the Clough-Tocher splitting technique that ensures locality. In particular, the splines are locally characterized by an interpolation problem described by Hermite data, which resembles the standard macro-element concepts developed for C1 splines on triangulations.
Keywords: quadratic triangle, quadratic triangulation, isogeometric functions, Clough-Tocher refinement, spline space, dimension, basis functions
Published in DiRROS: 24.03.2025; Views: 139; Downloads: 67
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55. Influence of vineyard location, cluster thinning and spontaneous alcoholic fermentation on wine compositionFranc Čuš, Anastazija Jež Krebelj, Mateja Potisek, 2025, original scientific article Abstract: The influence of the vineyard location, the yield per vine and the type of alcoholic fermentation on the composition of Merlot wine from two consecutive vintages was investigated in a simultaneous experiment. Grapes from two locations and two crop loads per vine, from controlled and thinned vines, were vinified. At the same time, grapes from control vines were vinified with inoculated and spontaneous alcoholic fermentation. Comparisons of the wine composition were made using a targeted metabolomic approach, microbiological analysis and sensory evaluation. It has been confirmed that the composition of Merlot wine is essentially determined by the location of the vineyard. The analytical marker used to distinguish the two locations was the content of 3-mercaptohexan-1-ol (significantly higher in location B with 38–130%). It has also been shown that the type of alcoholic fermentation has a greater influence on the composition of the wine than the crop load. The analytical marker used for the cluster thinning was the pH of the wine, which increased significantly by 0.03 to 0.08 units with the lower crop load, and for the type of alcoholic fermentation, the concentration of 2-phenethyl acetate, which relates to the sum of acetates and 2-phenylethanol, which increased significantly by 58–299%, 54–218%, and 24–46% in the spontaneously fermented wines. Both the location of the vineyard and spontaneous alcoholic fermentation influenced the significant differences in the sensory characteristics of the wine, while cluster thinning had no such influence. The other influences of the two technical factors on the wine composition depended on the location of the vineyard and the vintage. It can also be concluded that spontaneous alcoholic fermentation reduced the influence of the vintage on the wine composition, while the opposite was the case with cluster thinning.
Keywords: terroir, crop load, spontaneous alcoholic fermentation, non-Saccharomyces yeasts
Published in DiRROS: 24.03.2025; Views: 120; Downloads: 45
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56. Prospective observational study of COVID-19 vaccination in patients with thoracic malignancies : adverse events, breakthrough infections and survival outcomesUrška Janžič, Andrej Janžič, Abed Agbarya, Urška Bidovec, Katja Mohorčič, Marina Čakš, Peter Korošec, Matija Rijavec, Erik Škof, 2024, original scientific article Abstract: Abstract: Due to the devastating COVID-19 pandemic, a preventive tool in the form of vaccination was introduced. Thoracic cancer patients had one of the highest rates of morbidity and mortality due to COVID-19 disease, but the lack of data about the safety and effectiveness of vaccines in this population triggered studies like ours to explore these parameters in a cancer population. Out of 98 patients with thoracic malignancies vaccinated per protocol, 60–75% experienced some adverse events (AE) after their first or second vaccination, most of them were mild and did not interfere with their daily activities. Out of 17 severe AEs reported, all but one were resolved shortly after vaccination. No significant differences were noted considering AE occurrence between different cancer therapies received after the first or second vaccination dose, p = 0.767 and p = 0.441, respectively. There were 37 breakthrough infections either after the first (1), second (13) or third (23) vaccine dose. One patient died as a direct consequence of COVID-19 infection and respiratory failure, and another after disease progression with simultaneous severe infection. Eight patients had moderate disease courses, received antiviral therapies and survived without consequences. Vaccination did not affect the time to disease progression or death from underlying cancer.
Keywords: thoracic malignancies, cancer therapy, COVID-19 vaccination, adverse events, breakthrough infection
Published in DiRROS: 24.03.2025; Views: 133; Downloads: 51
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57. Protein stacking on the APTES-functionalized pyrochlore Bi2Ru2O7 clusters for ultrasensitive and selective immunosensingNikola Tasić, Nika Vranešič, Dino Metarapi, Kristina Mervič, Milan Žunić, Aleksandra Dapčević, Matjaž Finšgar, Samo B. Hočevar, 2025, original scientific article Abstract: With their unique physicochemical properties, such as metallic-like conductivity, favorable (electro)catalytic properties, electrochemical stability, and ease of functionalization, pyrochlores have found applications in various fields such as solid oxide fuel cells, batteries, thick film resistors, and temperature sensors; however, there are no reports on their application in electrochemical immunosensing. In this study, we exploited the (electro)catalytic nature and stability of the pyrochlore Bi2Ru2O7 clusters silanized with (3-aminopropyl)triethoxysilane (APTES) to demonstrate their potential for the effective stacking of functional proteins. Characterization of the clusters by XPS disclosed a dual environment of Bi, also indicating the presence of Bi2O3 alongside APTES-Bi2Ru2O7 clusters and, importantly, the predominant involvement of pyrochlore moieties in subsequent protein stacking. After stacking protein A and antibodies, the immunosensor revealed a nearly interference-free operation, high sensitivity, a detection limit of 118 fM SARS-CoV-2 spike protein, and operation in a wide examined concentration range of 10−5−10−1 μg mL−1 with an r2 of 0.98. In combination with a short incubation time of 30 min, the pyrochlore-based immunosensor provides a solid platform for future point-of-need applications.
Keywords: Bi2Ru2O7 pyrochlore, APTES, SARS-CoV-2, spike protein, immunosensors, electrochemical
Published in DiRROS: 24.03.2025; Views: 138; Downloads: 83
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58. The effect of soil conditions on climate-growth correlations at two Pinus nigra sitesMathieu Magnier, Jernej Jevšenak, Radosław Puchałka, Marcin Miroslav Klisz, 2025, original scientific article Abstract: Climate change is modifying precipitation distribution and increasing drought events frequency, leading to decline in many stands. Pinus nigra was introduced to Poland in the 19th century as a measure to mitigate negative effects of soil pollution. This species is also known to be well adapted to drought conditions. However, its response to drought on different soil conditions remains unclear. The aim is to investigate the growth relation of P. nigra to drought and its resilience under the same climatic conditions but different soil types (fertile and poor soils) in central Poland. Two mature stands of P. nigra were selected, one on fertile soil and one on poor soil. Tree-ring data were collected and analysed to assess growth patterns and climate sensitivity. Resilience indices were calculated for seven common drought years, i.e. 1940, 1954, 1963, 1976, 2003, 2006 and 2015, to compare the impact of soil conditions on drought response. The study found similar climate-growth correlations for both soil types, with March temperatures and summer precipitation positively affecting growth, highlighting the significant influence of local climatic conditions on growth. However, resilience to drought varied between poor and fertile soil, with opposite trends observed in the drought year 1976 (characterized by dry June, wet July and dry August) and in the drought years 1963 and 2006 (characterized by wet June and dry July and August). With a higher resilience for the trees on poor soil in 1976 and a higher resilience on fertile soil in 1963 and 2006. Moreover, differences were not consistently observed: only 3 of the 7 years were significantly different. The study indicates that soil conditions partially influence the resilience of P. nigra to drought, but the relationship seems drought episode-dependent. Relationships between soil fertility and climate-growth dependencies are complex, and to draw more robust conclusions, further studies are needed, incorporating additional soil types.
Keywords: resilience, drought, water capacity, fertility, Poland
Published in DiRROS: 21.03.2025; Views: 140; Downloads: 146
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