Iskanje po repozitoriju

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Povzetek: In the structural analysis of fluid-conveying pipes, dynamic instabilities can occur at specific values of the flow velocity, depending on the geometry as well as the material parameters of the pipe and the interior fluid. These critical points fall into the broader category of Hopf bifurcations. Typical numerical models of this problem employ a one-dimensional weighted residual method, leading to a velocity-dependent eigenvalue problem. The solutions form eigencurves, and the critical points are characterized by eigenvalues with vanishing real parts. In this paper, we show that critical points can be computed directly as solutions to a single three-parameter eigenvalue problem. In addition, we employ a recently developed method for computing individual eigencurves, based on the concept of exponential residual relaxation. For the discretization of the weak form, we use a finite element method with a particular version of $C^1$-continuous high-order spectral elements, suited for fourth-order differential equations, and we discuss the differences compared to the more commonly used weighted residual method based on the basis functions of a linear Euler-Bernoulli beam. Four numerical examples demonstrate the effectiveness of the implemented algorithms. For verification, we provide a detailed derivation of analytical solutions for special cases.
Ključne besede: pipes, Euler-Bernoulli beam, stability, Hopf bifurcation, multiparameter eigenvalue problem, spectral element method
Objavljeno v DiRROS: 20.11.2025; Ogledov: 117; Prenosov: 59
Celotno besedilo (2,93 MB)
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Povzetek: This study examines the sense of place (SOP) and identity in peri-urban landscapes, which serve as borderscapes between urban and rural areas. It applies SOP both as a cultural ecosystem service and a phenomenological construct to explore how residents and visitors connect with these landscapes. Using a mixed-methods approach with over seven hundred participants from Ljubljana, Koper, and Kranj, Slovenia, the study maps and evaluates how residents and visitors perceive their environment. The results show that residents have a stronger SOP, but the importance of places for SOP and other cultural services is similar for both residents and visitors. Participatory mapping effectively identified areas of high SOP value, revealing strong connections to hills, bodies of water, biodiverse areas, and small settlements. Conflicts between land-use planning and local values were identified, emphasising the need for flexible, participatory spatial planning to reflect diverse, locally specific perspectives in decision-making.
Objavljeno v DiRROS: 20.11.2025; Ogledov: 142; Prenosov: 40
Celotno besedilo (3,34 MB)

Ključne besede: public space, research, urban planning
Objavljeno v DiRROS: 20.11.2025; Ogledov: 150; Prenosov: 49
Celotno besedilo (2,17 MB)

Povzetek: Long-term monitoring of stable isotopes in precipitation (δ18O, δ2 H), alongside meteorological data, is key to understanding how large-scale hydroclimate variability influences regional and local climate. This study presents one of the longest records in Central and Southeastern Europe: the multi-decadal (1981–2024) dataset of monthly composite precipitation stable isotope records from Ljubljana, Slovenia. The δ18O, δ2 H, and d-excess values are increasing (+0.02 ‰, +0.18 ‰, and +0.05 ‰ per year, respectively), consistent with regional warming. Seasonal patterns were evident, with elevated d-excess values during autumn. The decomposition of the δ18O, δ2 H and d-excess time series using Hilbert-Huang Transform revealed statistically significant annual oscillations in all variables. These oscillations correlated strongly with the annual oscillation of temperature, but a lag of 2–3 months was identified for d-excess. Lower-frequency (multi-year) oscillations of d-excess were also observed. HYSPLIT back-trajectory analysis confirmed a significant contribution of Mediterranean-sourced air masses to autumn precipitation, but did not explain d-excess oscillations. Similar results were observed also for coastal (Portoroˇz, Slovenia) and continental (Vienna, Austria) stations. The findings imply an accelerating, exponential-like isotopic response to warming that has already propagated into the water cycle, providing isotope evidence that precipitation-surface water-groundwater interactions in investigated region changed in last decade.
Ključne besede: precipitation stable isotopes, trend analysis, Hilbert-Huang transform, ensemble empirical mode decomposition, HYSPLIT
Objavljeno v DiRROS: 19.11.2025; Ogledov: 119; Prenosov: 52
Celotno besedilo (7,50 MB)
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Povzetek: Introduction: In addition to its direct cytotoxic effects, ablative therapies as electrochemotherapy (ECT) can elicit indirect antitumor effects by triggering immune system responses. Here, we comprehensively analyzed this dual effectiveness of intratumoral ECT with chemotherapeutic drugs bleomycin (BLM), oxaliplatin (OXA), and cisplatin (CDDP). Our aim was to determine if ECT can act as in situ vaccination and thereby induce an abscopal effect. By evaluating ECT’s potential for in situ vaccination, our goal was to pave the way for future advancements for its combination with emerging (immuno)therapies, leading to enhanced responses and outcomes. Methods: We employed two mouse tumor models, the immunologically cold B16F10 melanoma and 4T1 mammary carcinoma, to explore both local and systemic (i.e., abscopal) antitumor effects following equieffective intratumoral ECT with BLM, OXA, and CDDP. Through histological analyses and the use of immunodeficient and metastatic (for abscopal effect) mouse models, we identified and compared both the cytotoxic and immunological components of ECT’s antitumor efficiency, such as immunologically recognizable cell deaths (immunogenic cell death and necrosis) and immune infiltrate (CD11+, CD4+, CD8+, GrB+). Results: Differences in immunological involvement after equieffective intratumoral ECT were highlighted by variable kinetics of immunologically recognizable cell deaths and immune infiltrate across the studied tumor models. Particularly, the 4T1 tumor model exhibited a more pronounced involvement of the immune component compared to the B16F10 tumor model. Variances in the antitumor (immune) response were also detected based on the chemotherapeutic drug used in ECT. Collectively, ECT demonstrated effectiveness in inducing in situ vaccination in both tumor models; however, an abscopal effect was observed in the 4T1 tumor model only. Conclusions: This is the first preclinical study systematically comparing the immune involvement in intratumoral ECT’s efficiency using three distinct chemotherapeutic drugs in mouse tumor models. The demonstrated variability in immune response to ECT across different tumor models and chemotherapeutic drugs provides a basis for future investigations aimed at enhancing the effectiveness of combined treatments.
Ključne besede: electroporation, chemotherapeutic drugs, mouse tumor models
Objavljeno v DiRROS: 19.11.2025; Ogledov: 164; Prenosov: 77
Celotno besedilo (18,91 MB)
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