1. Temperature and heat flux measurements from firebrand piles using color ratio pyrometryStanislav Stoliarov I., Peter B. Sunderland, 2026, izvirni znanstveni članek Povzetek: Glowing firebrands are a key ignition source in Wildland–Urban Interface fires, yet their thermal characterization is challenging due to small size, irregular shape and sensitivity to environmental conditions. This study extends color ratio pyrometry from a single firebrand to firebrand piles to measure spatially resolved surface temperatures, heat flux to a remote location, and radiative loss fraction in a wind tunnel at 0.9–2.7 m/s. A Digital Single Lens Reflex camera, calibrated against a blackbody furnace, recorded temperatures at 1 Hz in the range 873–1473 K. Mean surface temperatures were measured with color ratio pyrometry and determined to be 1130–1260 K, with localized hot spots on the windward side of the pile. Radiant heat flux at a point 9.6 cm above the firebrand pile was computed using a pixel-wise view factor method with surface-specific emissivity and transmittance. This approach reproduced the temporal trends measured by a Schmidt–Boelter heat flux gauge, with peaks near 6 kW/m2. Including a correction for hot, non-glowing regions below 873 K improved agreement across all wind speeds, keeping the average error below 9%. The radiative loss fraction, measured via carbon oxide calorimetry, stabilized at 0.20–0.23 during the first 100 s of the glowing phase.
Ključne besede: firebrands, heat flux, color ratio pyrometry, pyrometry, image processing
Objavljeno v DiRROS: 17.07.2026; Ogledov: 186; Prenosov: 106
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2. Rafinacija aluminijevih gnetnih zlitin z uporabo višjih deležev sekundarnih surovinUroš Kovačec, Franc Zupanič, Tonica Bončina, 2026, izvirni znanstveni članek Ključne besede: aluminium, refinement, flux, cleanliness, non-metallic inclusion, rotary injection, alkali element
Objavljeno v DiRROS: 16.06.2026; Ogledov: 277; Prenosov: 111
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4. Non-destructive ultrasonic inspections of small-scale mock-ups provided with advanced tungsten armours for DEMO divertor targetRiccardo De Luca, Emanuele Cacciotti, Marco Cerocchi, Aljaž Iveković, Petra Jenuš, Marius Wirtz, 2025, izvirni znanstveni članek Povzetek: Within the framework of the EUROfusion Consortium, the Characterization of armour, heat sinks materials and joints sub-project of the Work Package Material (WP-MAT) has been dedicated to the development of different tungsten (W) monoblock mock-ups equipped with advanced materials for divertor target applications in the EU-DEMO fusion reactor. Assessing the status of the relevant joining interfaces of these mock-ups, not only after fabrication but throughout the whole component lifetime, plays a key role in the qualification process. At the ENEA Special Technologies Laboratory (TES), a number of facilities have been built to perform non-destructive inspections of plasma-facing components for fusion applications by ultrasonic testing (UT). The present work reports on the results of the UT inspections assessing the structural integrity of the relevant joining interfaces of three small-scale mock-ups provided with advanced W armour materials, specifically W-matrix with W2C inclusions consolidated by Spark Plasma Sintering (SPS), K-doped rolled W and K-doped laminated W. The UT examinations are carried out after fabrication and after the high heat flux tests (HHFT) at the neutral beam facility GLADIS. All results confirm the high-quality joining achieved by HIP and HRP. During the HHF tests of mock-ups, after a few hundred HHFT cycles defects are detected at the joining interfaces, due to debonding, delamination and W material cracks mainly affecting the loaded zone. The ultrasonic pulse-echo technique provides not only the size and position of the defects in the plane orthogonal to the ultrasonic beam, but also their depth in the material. During the analysis, the probe is inserted inside the pipe and the mock-up is examined in a cylindrical configuration. The coupling medium (demineralized water) is poured only inside the pipe. The main inspection parameters and the piezoelectric probes are chosen to obtain the maximum resolution in accordance with the thickness and joining interfaces to be analyzed.
Ključne besede: DEMO, divertor, advanced tungsten, high heat flux test, non-destructive test, ultrasonic examination
Objavljeno v DiRROS: 03.09.2025; Ogledov: 721; Prenosov: 458
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5. Optimized flux single-crystal growth of the quantum spin liquid candidate ▫$NdTa_7O_{19}$▫ and other rare-earth heptatantalates, ▫$ErTa_7O_{19}$▫ and ▫$GdTa_7O_{19}$▫Lia Šibav, Matic Lozinšek, Zvonko Jagličić, Tina Arh, Panchanana Khuntia, Andrej Zorko, Mirela Dragomir, 2025, izvirni znanstveni članek Povzetek: Single crystals are essential for characterizing a wide range of magnetic states, including exotic ones such as quantum spin liquids. This study reports a flux method for growing single crystals of NdTa7O19, the first quantum spin liquid candidate on a triangular spin-lattice with dominant Ising-like spin correlations. Purple NdTa7O19 single crystals with hexagonal morphology were successfully grown by using a K2Mo3O10–B2O3 flux. With lateral sizes up to 3.5 mm and a thickness up to 2 mm, these are the largest dimensions reported to date. The chemical composition was confirmed by powder and single-crystal X-ray diffraction along with scanning electron microscopy with energy dispersive X-ray spectroscopy. Aiming for an accurate determination of the magnetic anisotropy and its effect on the magnetic properties, NdTa7O19 crystals were additionally analyzed by magnetic susceptibility, revealing a substantial anisotropy without long-range magnetic ordering down to 2 K. Single crystals of two novel rare-earth heptatantalates, ErTa7O19 and GdTa7O19, were also grown, and their magnetic properties investigated. The magnetic anisotropy of ErTa7O19 closely resembles that of isostructural NdTa7O19, indicating the possibility of a similar exotic magnetic ground state. In contrast, GdTa7O19 shows paramagnetic behavior, consistent with previous results obtained for polycrystalline samples.
Ključne besede: quantum spin liquid, single-crystal growth, magnetic properties, flux, rare-earth tantalates
Objavljeno v DiRROS: 14.07.2025; Ogledov: 862; Prenosov: 610
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6. High-Intensity Fast-Response Electric Radiant Panel (HIFREP) to impose fire equivalent heat fluxes on building elements with enhanced thermal boundary conditions accuracyFlorian Put, Balša Jovanović, Evelien Symoens, Andrea Lucherini, Bart Merci, Ruben Van Coile, 2025, izvirni znanstveni članek Povzetek: Bench-scale fire testing has gained popularity as a highly controllable and cost-effective solution, overcoming many of the shortcomings of traditional large-scale fire resistance tests. Whereas gas-fired radiant panels have demonstrated significant success in this area, the present study introduces a novel High-Intensity Fast-Response Electric radiant Panel (HIFREP). Utilizing electrically operated radiation emitters, it provides more precise and quasi-instantaneous control over the thermal boundary conditions. HIFREP delivers high and stable heat fluxes up to 105 kW/m2 , and, due to the low thermal inertia of the emitters, can rapidly adjust its output to changes in the input. In this regard, the time constant of the emitters has been found to be less than 1 s, both during heating and cooling. It eliminates gas combustion and hence avoids the need for extraction hoods when testing the fire performance of non-combustible materials, making it suitable for traditional structural testing laboratories. The presented High-Intensity Fast-Response Electric radiant Panel also provides a reliable tool for the validation of FEM simulation results by accurately replicating the thermal boundary conditions in structural fire engineering analyses.
Ključne besede: radiant panel, fire testing, heat transfer, radiation, heat flux, thermal boundary conditions
Objavljeno v DiRROS: 16.06.2025; Ogledov: 1036; Prenosov: 509
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7. Experimental study of fire propagation on sloped roof with building applied photovoltaicsReidar Stølen, Janne Siren Fjærestad, Ragni Fjellgaard Mikalsen, Grunde Jomaas, 2024, objavljeni znanstveni prispevek na konferenci Povzetek: Photovoltaic modules have been shown to influence how a fire propagates across a flat roof, but the circumstances for which building attached photovoltaic (BAPV) modules promote fire propagation on a sloped roof is not studied in detail. Therefore, a series of small-medium- and large-scale experiments on a sloped roof with a BROOF(t2)-rated bituminous roof membrane on a wood chipboard substrate has been performed. Steel plates mimicking non-combustible photovoltaic (PV) modules were placed at different distances above the roof. Different sized wood cribs placed in the gap between the roof and the PV module were used as the ignition source. Similarly to findings for flat roofs, the experiments showed that the gap distance and the size of the ignition source are key factors for how far the fire propagates from the starting point. This supports that BAPV installations affect the fire dynamics on roofs. As such, the complete system of roof composition and PV installation needs to be considered as a whole to ensure adequate fire safety levels.
Ključne besede: photovoltaic systems, fire propagation, roof safety, ignition source, heat flux
Objavljeno v DiRROS: 12.02.2025; Ogledov: 958; Prenosov: 539
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8. High-Intensity Fast-Response Electric radiant Panel (HIFREP) for increased accuracy on thermal boundary conditions during fire testingFlorian Put, Balša Jovanović, Evelien Symoens, Andrea Lucherini, Bart Merci, Ruben Van Coile, 2024, objavljeni znanstveni prispevek na konferenci Povzetek: Fire resistance tests rely on the use of standardized furnaces to apply specific thermal boundary conditions to assess the performance of construction materials and systems in fire conditions. However, these tests are very expensive and encounter challenges related to repeatability and uncertainties in establishing thermal boundary conditions. Moreover, their incapacitance to tailor experiments hinders advancements in understanding structural behaviour during fire exposure. In this work, a novel type of radiant panel, that operates on electricity, is introduced: the High-Intensity Fast-Response Electric radiant Panel (HIFREP). This innovation offers enhanced sustainability performance while ensuring more precise control over thermal boundary conditions. By eliminating the need for gas combustion, the panel can be used in a traditional structural testing lab to investigate non-combustible materials (e.g. concrete), without requiring extraction hoods and other provisions. The presented electric radiant panel system represents a significant step forward from fire resistance furnace testing.
Ključne besede: radiant panel, fire testing, heat transfer, radiation, heat flux, fire safety, thermal boundary conditions
Objavljeno v DiRROS: 19.12.2024; Ogledov: 1345; Prenosov: 672
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9. Animal life in the shallow subseafloor crust at deep-sea hydrothermal ventsMonika Bright, Sabine Gollner, André Luiz de Oliveira, Salvador Espada-Hinojosa, Avery Fulford, Tihomir Makovec, Tinkara Tinta, 2024, izvirni znanstveni članek Povzetek: It was once believed that only microbes and viruses inhabited the subseafloor crust beneath hydrothermal vents. Yet, on the seafloor, animals like the giant tubeworm Riftia pachyptila thrive. Their larvae are thought to disperse in the water column, despite never being observed there. We hypothesized that these larvae travel through the subseafloor via vent fluids. In our exploration, lifting lobate lava shelves revealed adult tubeworms and other vent animals in subseafloor cavities. The discovery of vent endemic animals below the visible seafloor shows that the seafloor and subseafloor faunal communities are connected. The presence of adult tubeworms suggests larval dispersal through the recharge zone of the hydrothermal circulation system. Given that many of these animals are host to dense bacterial communities that oxidize reduced chemicals and fix carbon, the extension of animal habitats into the subseafloor has implications for local and regional geochemical flux measurements. These findings underscore the need for protecting vents, as the extent of these habitats has yet to be fully ascertained.
Ključne besede: subseafloor, hydrothermal vents, tubeworms, larvae, vent fluids, bacterial communities, geochemical flux, geochemistry, marine biology
Objavljeno v DiRROS: 22.10.2024; Ogledov: 1145; Prenosov: 1624
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10. Dissolved gaseous mercury production and sea-air gaseous exchange in impacted coastal environments of the northern Adriatic SeaFederico Floreani, Nicolò Barago, Katja Klun, Jadran Faganeli, Stefano Covelli, 2023, izvirni znanstveni članek Povzetek: The northern Adriatic Sea is well known for mercury (Hg) contamination mainly due to historical Hg mining which took place in Idrija (Slovenia). The formation of dissolved gaseous mercury (DGM) and its subsequent volatilisation can reduce the amount of Hg available in the water column. In this work, the diurnal patterns of both DGM production and gaseous elemental Hg (Hg0) fluxes at the water-air interface were seasonally evaluated in two selected environments within this area, a highly Hg-impacted, confined fish farm (VN: Val Noghera, Italy) and an open coastal zone less impacted by Hg inputs (PR: Bay of Piran, Slovenia). A floating flux chamber coupled with a real-time Hg0 analyser was used for flux estimation in parallel with DGM concentrations determination through in-field incubations. Substantial DGM production was observed at VN (range = 126.0–711.3 pg L−1) driven by both strong photoreduction and possibly dark biotic reduction, resulting in higher values in spring and summer and comparable concentrations throughout both day and night. Significantly lower DGM was observed at PR (range = 21.8–183.4 pg L−1). Surprisingly, comparable Hg0 fluxes were found at the two sites (range VN = 7.43–41.17 ng m−2 h−1, PR = 0–81.49 ng m−2 h−1), likely due to enhanced gaseous exchanges at PR thanks to high water turbulence and to the strong limitation of evasion at VN by water stagnation and expected high DGM oxidation in saltwater. Slight differences between the temporal variation of DGM and fluxes indicate that Hg evasion is more controlled by factors such as water temperature and mixing conditions than DGM concentrations alone. The relative low Hg losses through volatilisation at VN (2.4–4.6% of total Hg) further confirm that static conditions in saltwater environments negatively affect the ability of this process in reducing the amount of Hg retained in the water column, therefore potentially leading to a greater availability for methylation and trophic transfer.
Ključne besede: Idrija mercury mine, mercury evasion, fish farm, flux chamber, water-air exchange, Adriatic Sea, Idrijski rudnik živega srebra, ribogojnica, pretočna komora, izmenjava voda-zrak, Jadransko morje
Objavljeno v DiRROS: 12.07.2024; Ogledov: 1560; Prenosov: 863
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