951. Strategic management approaches for developing sustainable renewable heat supply in local communities : A case studyEdvard Košnjek, Boris Sučić, Fouad Al-Mansour, Aleksandar Kavgić, 2025, original scientific article Abstract: The importance of local sustainable energy projects in the transition to a climate-neutral society is widely rec ognised, yet strategic planning at the local level often lacks structure and consistency. This paper presents an integrated methodology combining established strategic management tools—such as SWOT analysis, multi- criteria decision-making methods for prioritising factors and strategies, and strategic formulation matrices—to develop and implement sustainable development strategies in the energy sector. The seven-step process includes defining the national sustainable development framework, identifying strategic orientations, assessing local conditions, evaluating the relevance of key factors, formulating strategies, and determining performance in dicators. The method was tested through the development of 36 strategies for a Slovenian municipality, with three top-ranked strategies implemented as pilot cases. For the proposed woodchip-based combined heat and power system, the economic analysis indicated a net present value of € 144,134 and an internal rate of return of 7.2%, which exceeds the weighted average cost of capital of 5.0%. In the second case, the utilisation of excess heat from industrial processes in the district heating system suggested potential annual savings of over 2.4 million, with an estimated return on investment within five years, assuming partial public co-financing. These f indings confirm the practical applicability of the proposed approach and its usefulness in supporting local au thorities in the development of effective and economically viable strategies for the energy transition.
Published in DiRROS: 18.09.2025; Views: 303; Downloads: 87
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952. Smectic bubble lasers for acoustic and pressure measurements in air and waterZala Korenjak, Matjaž Humar, 2025, original scientific article Abstract: Recently, we have demonstrated that dye-doped soap and smectic bubbles can be used as lasers. Here we investigated smectic bubble lasers for their potential to measure pressure changes in both air and water and as microphones. Smectic bubbles consist of a very thin smectic liquid crystal film. In contrast to ordinary soap bubbles, smectic bubbles are highly stable. When illuminated with a pump laser, they exhibit whispering gallery mode lasing with sharp, regularly spaced peaks in the emission spectrum. The bubbles enable extremely precise measurement of pressure changes based on wavelength shifts of the lasing peaks. We have demonstrated that smectic bubbles can be inflated under water and used as water pressure sensors. Additionally, we have used smectic bubble lasers in air as highly sensitive microphones to detect sound waves across different frequencies with advantages over conventional microphones. Their extremely thin walls result in negligible acoustic impedance. Furthermore, bubble size changes due to pressure variations depend only on bubble volume, eliminating the need for calibration and making performance independent of manufacturing precision or defects. This also leads to a linear amplitude response, and a flat frequency response over a wide range of frequencies. Unlike most microphones, bubble lasers can measure arbitrarily small frequencies down to static pressure, making them promising candidates for acoustic wave detection in various applications.
Keywords: smectic bubbles, liquid crystal lasers, smectic liquid crystals, water pressure
Published in DiRROS: 18.09.2025; Views: 258; Downloads: 136
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953. End-of-life of renewable energy technologies in urban environments. A state-of-the-art on installation trends, materials, and best practices in the EUMarilena De Simone, Daniele Campagna, Luisa F. Cabeza, Rocío Pineda-Martos, Paulo Santos, Janez Turk, Viorel Ungureanu, Gabriel Zsembinszki, 2025, review article Abstract: The European Commission is promoting the production of thermal energy and electricity from renewable sources, coupled with storage systems, to decarbonize the built environment. However, these technologies use prevalently virgin raw materials, and end-of-life (EoL) circular frameworks are still difficult to be implemented due to technical, regulatory, and market barriers. This paper aims to present a state-of-the-art on the trends in installation, materials, EoL strategies, and companies active in renewable energy systems recycling. Solar, wind, and geothermal sources are examples of technologies easily incorporated into cities. The purpose is to provide information to stakeholders that should design technical solutions according to circularity criteria. The information, from both scientific and grey literature, showed that solar technologies represent the most widespread type of systems, with a considerable number of best practices and companies specialized in recycling. Wind technology follows in installation trends and activity of reuse-oriented companies. Geothermal, on the other hand, offers a reduced number of reference examples. Furthermore, this review provides an overview of the installation and potential EoL scenarios of electrical and thermal energy storage systems, highlighting significant differences in the implementation of circularity strategies. The study closes with considerations and suggestions for practical applications.
Keywords: circular economy, end-of-life, solar energy, wind energy, geothermal energy, built environment
Published in DiRROS: 18.09.2025; Views: 251; Downloads: 140
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954. Can low-cost sensors (LCS) enhance air quality monitoring for personal pollution exposure assessment?Anja Ilenič, Alenka Mauko Pranjić, Janez Ščančar, Radmila Milačič Ščančar, Kumar Prashant, 2025, original scientific article Abstract: Laboratory and field assessments of low-cost sensors (LCS) are essential for ensuring the accuracy of PM2.5 measurements collected by citizens in air quality campaigns. Evaluation of Sensirion SPS30 (LCS SPS30) in controlled laboratory setting showed a coefficient of determination (R2) ranging from 0.81–0.99 and a root mean square error (RMSE) from 0.81–61.72 μg m−3, at average concentration of 21.5 μg m−3. In contrast, co-location assessment at an average concentration of 9 μg m−3 resulted in R2 of 0.5 and a RMSE of 6.82 μg m−3. The results demonstrated that the sensor met micro-environmental monitoring standards (accuracy < 25%) and United States Environmental Protection Agency's performance criteria (RMSE ≤ 7 μg m−3, R2 > 0.7) only at relative humidity (RH) levels below 60%, emphasising its strong sensitivity to RH and the need for RH-dependent data corrections. The observed underestimation or overestimation of PM2.5 readings was primarily attributed to variations in particle composition and concentration. Despite accuracy variations, LCSs can effectively capture spatiotemporal urban air quality patterns and identify pollution hotspots in community monitoring, particularly in low-pollution environments. In a citizen-led PM2.5 monitoring campaign in Maribor, Slovenia, the lowest concentrations were recorded at 15:00 (2.9 μg m−3), while the highest occurred during the morning rush-hour (4.8 μg m−3), likely attributed to the planetary boundary layer’s impact on atmospheric particulate dispersion. Spatial analysis revealed that hotspots clustered near intersections, where vehicle waiting time is the longest.
Keywords: particulate matter, low-cost sensor, Sensirion SPS30, citizen science, calibration
Published in DiRROS: 18.09.2025; Views: 265; Downloads: 176
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955. Primerjava naprednih 3D tehnologij za skeniranje pri nadzoru kvalitete industrijskih izdelkovJakob Fabjan, Adela Pišmo, Vesna Pungerčar, Slavko Arh, 2025, published professional conference contribution Abstract: 3D skeniranje je nekontaktna tehnologija, s katero lahko fizični objekt pretvorimo v digitalni model, kar industriji omogoča obratni inženiring in nadzor kakovosti (preverjanje skladnosti s predpisi). Pri nadzoru kakovosti se pogosto uporabljajo napredne tehnologije kot je 3D skeniranje. Vendar imajo te napredne tehnike določene omejitve: če ima na primer predmet izvrtine ali če so poškodbe skrite v notranjosti, jih s temi metodami ne moremo zaznati. Takšne informacije pa so ključnega pomena za napovedovanje trajnosti materiala in odkrivanje skritih napak (razpoke, prisotnost vključkov, nehomogenost materiala). Zato se naša raziskava osredotoča na primerjavo treh različnih tehnik za zajem tridimenzionalnih podatkov industrijskega izdelka iz aluminija: 3D skeniranje s strukturirano svetlobo, 3D skeniranje z lasersko svetlobo in skeniranjem z uporabo računalniške tomografije (CT). Cilj je bil primerjati posamezne tehnike glede na natančnost izdelave v primerjavi s CAD modelom ter glede na količino in kakovost informacij, ki jih posamezna tehnika omogoča. Pri tem smo upoštevali, ali tehnika omogoča analizo zunanjih geometrijskih lastnosti materialov in drugih pomembnih značilnosti. Rezultati raziskave kažejo, da je kombinacija 3D skeniranja skupaj s CT analizo smiselna za preverjanje visoke kakovosti in boljše napovedi življenjske dobe industrijskega izdelka.
Keywords: 3D-skeniranje z lasersko triangulacijo, 3D-skeniranje s strukturirano svetlobo, CT-skeniranje, nadzor kakovost
Published in DiRROS: 17.09.2025; Views: 355; Downloads: 83
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956. Metal–support interaction between titanium oxynitride and Pd nanoparticles as a tool for tuning the selectivity of electrocatalytic hydrogenation of furfuralNik Maselj, Jan Trputec, Martin Šala, Kristina Mervič, Ivan Marić, Francisco Ruiz-Zepeda, Marjan Bele, Vasko Jovanovski, Nejc Hodnik, Primož Jovanovič, 2025, original scientific article Published in DiRROS: 17.09.2025; Views: 335; Downloads: 164
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957. Tomato spotted wilt virus in tomato from Croatia, Montenegro and Slovenia: genetic diversity and evolutionDijana Škorić, Jelena Zindović, Dorotea Grbin, Patrik Pul, Vladan Božović, Paolo Margaria, Nataša Mehle, Anja Pecman, Zala Kogej Zwitter, Denis Kutnjak, Ana Vučurović, 2025, original scientific article Abstract: Tomato spotted wilt orthotospovirus (TSWV) is a major plant pathogen causing significant economic losses in tomato production worldwide. Understanding its genetic diversity and evolutionary mechanisms is crucial for effective disease management. This study analyzed TSWV isolates from symptomatic tomato plants collected across Croatia, Montenegro and Slovenia between 2020 and 2024. High-throughput sequencing (HTS) was employed to obtain whole-genome sequences, followed by phylogenetic analyses to assess genetic variability and relationships among isolates from these three countries and other isolates of worldwide geographic origin. Phylogenetic analyses placed all studied isolates within the L1-M3-S3 genotype, commonly associated with solanaceous crops in Europe. While Croatian and Slovenian isolates exhibited high genetic similarity, Montenegrin isolates clustered in a distinct subgroup, showing closer relationships to Asian and Mediterranean accessions. Despite the severe disease symptoms observed, no substitutions in the NSm protein associated with resistance-breaking (RB) phenotypes were detected. These findings suggest that additional virome components, environmental factors or so far unknown mechanism(s) may contribute to infection and disease severity in tomato and strongly support the need of continuous surveillance of TSWV genetic diversity in order to inform breeding programs and develop sustainable management strategies to mitigate future outbreaks.
Keywords: tomato, HTS, phylogeny, TSWV, plant virus
Published in DiRROS: 16.09.2025; Views: 323; Downloads: 147
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958. Stable implementation of a Chen-based enhancement to the Lee phase-change model for CFD simulation of film boiling under energetic melt-coolant interaction conditionsMihael Boštjan Končar, Matej Tekavčič, Mitja Uršič, Mihael Sekavčnik, 2026, original scientific article Abstract: This study investigates heat and mass transfer during energetic melt-coolant interactions, focusing on film boiling around a hot melt particle in subcooled convective flow. The considered conditions, free-flow velocities of a few m/s, melt particle temperatures of several thousand K, particle diameters of several tens of a μm, and liquid subcooling of several tens of a K, align with TREPAM experiments (CEA, France). A two-phase computational fluid dynamics framework, based on the Volume of Fluid method, is used. An improved phase-change model is implemented, combining Chen’s explicit formulation of the phase-change intensity factor with the robustness of the conventional Lee model. The approach reduces sensitivity to empirical parameters and enhances phase-change localisation. Additional constraints on the intensity factor ensure numerical stability under extreme thermal conditions relevant to vapour energetic melt-coolant interactions. Simulations of TREPAM experiments demonstrate improved heat flux predictions and enhanced flow dynamics capture. Analysis of the simulated velocity fields reveal secondary flows in the vapour wake, impacting heat and mass transfer and emphasizing the need to resolve vapor-phase flow conditions. To fully validate proposed modifications to phase-change model further numerical and experimental investigation is required, focusing on vapour film morphology and localized heat transfer intensity.
Keywords: film boiling, extreme thermal conditions, phase-change modelling, computational fluid dynamics, two-phase flow
Published in DiRROS: 16.09.2025; Views: 242; Downloads: 111
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