1231. Effects of groundwater flow on end-temperature of closed-loop systems used for coolingSimona Adrinek, Joerg Prestor, Simona Pestotnik, Nina Rman, 2025, izvirni znanstveni članek Povzetek: Stable subsurface temperatures provide a reliable source of shallow geothermal energy. This research is one of a few that investigates the potential of closed-loop systems for cold storage facilities. We listed 47 cold storage facilities in Slovenia and evaluated the capacity of two 50 m deep borehole heat exchangers that would penetrate one of five intergranular aquifers. As the Slovenian legislation does not define temperature thresholds of the heat carrier fluid, we applied – 3 °C and +24 °C as conservative boundary conditions. First, we quantified the possible amount of injected waste heat with the analytical model (EED) using seven scenarios. Further, we upgraded our results with the three scenarios in the numerical model (FEFLOW), including groundwater flow. The calculation revealed that the optimal natural conditions for geothermal cooling of cold storages are in the Sava Basin, where fast groundwater flow (7.2 m/day) increases possible injected heat in numerical calculation to more than 900 % compared to analytical calculation. Cooling capacities decrease from the Sava to Drava, Mura, Savinja and Krško Basins. Our research quantitatively confirms that areas with groundwater flow are more conductive to restoring underground temperatures through the injection of waste heat from cooling cold storages than areas without groundwater flow.
Ključne besede: shallow geothermal energy, cold storage facility, intergranular aquifer, heat load, groundwater flow, Slovenia
Objavljeno v DiRROS: 28.08.2025; Ogledov: 384; Prenosov: 113
 Celotno besedilo (14,49 MB) |
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1233. Development of cellulose-degrading lactic acid bacterium Lactococcus cremoris by genetic engineeringPetra Štravs, Hélène David, Henri-Pierre Fierobe, Aleš Berlec, 2025, izvirni znanstveni članek Povzetek: Cellulose is one of the most abundant potential sources of carbon for sustainable microbial production of biochemicals. Lactic acid bacteria that produce a range of valuable metabolites are generally unable to grow on cellulose. Here, we aimed to develop the lactic acid bacteria Lactococcus cremoris for growth on cellulosic substrate. Genes encoding cellulases Cel5I, Cel9A and Cel5H from different cellulolytic bacteria were introduced into L. cremoris NZ9000 strain. The genes were designed for constitutive expression, with the produced cellulases being either secreted or displayed on the cell surface. Four promoters for cellulase gene expression and two noncovalent anchors for surface display of cellulases were evaluated using immunoblotting, confocal microscopy and flow cytometry. With the most effective promoter PepN, the cells secreted milligram amounts of cellulases per liter culture. The highest cellulolytic activity on amorphous (phosphoric-acid swollen cellulose, PASC) and microcrystalline (Avicel) cellulose was observed for the secreted Cel5H and Cel5I cellulases, respectively. The major cellodextrin produced by Cel5H and Cel5I was cellobiose, as determined by high performance anion exchange chromatography. The strains secreting cellulases outperformed the corresponding strains displaying the same cellulase on the surface in growth on PASC as the primary carbon source. The fastest growth was observed for the strain secreting Cel9A, followed by strain secreting Cel5H. By demonstrating growth of lactic acid bacteria expressing heterologous cellulases on PASC as a major carbon source for the first time, this study presents an important step towards the realization of consolidated bioprocesses involving lactic acid bacteria.
Ključne besede: Lactococcus cremoris, surface display
Objavljeno v DiRROS: 27.08.2025; Ogledov: 367; Prenosov: 191
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1235. Charismatic christianity as primal spirituality? : some observations from SloveniaIgor Jurekovič, 2025, izvirni znanstveni članek Povzetek: The global emergence of Charismatic Christianity ought to be regarded as one of the most consequential phenomena in contemporary history. With estimates reaching as high as 700 million adherents, Charismatics from various denominations have heralded the emergence of Global Christianity. Their considerable popularity has prompted numerous scholarly analyses aimed at elucidating the factors contributing to the emergence of Charismatic Christianity. Social scientists often elaborate on functionalist explanations, suggesting that the popularity of Charismatics can be understood through varying responses to social modernisation. Such explanations, however, frequently neglect the theological innovations inherent to Charismatic Christianity, which garners greater focus from theologians. Among them, Harvey Cox notably asserted that the widespread appeal of Charismatic Christianity can be attributed to its embodiment of experiential primal spirituality. Cox elaborated on three dimensions of Charismatic Christianity as a manifestation of primal spirituality: primal speech, primal piety, and primal hope. The objective of this article is to elucidate Cox’s argument and to examine the advantages of this approach while also offering insights derived from fieldwork conducted among Charismatics in Slovenia. The article posits that Cox’s approach merits appreciation among social scientists, as it identifies unique characteristics of Charismatic spirituality, while also acknowledging its limitations.
Ključne besede: karizmatično krščanstvo, prvinska duhovnost, religija, Slovenija, religijske spremembe
Objavljeno v DiRROS: 27.08.2025; Ogledov: 311; Prenosov: 220
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1236. Dynamic mechanical analysis of fpu bonded beech wood at various temperaturesMartin Capuder, Boris Azinović, Andreja Pondelak, Paweł Rutkowski, Magdalena Szumera, Matthew Schwarzkopf, Arkadiusz Kwiecień, Klaudia Śliwa-Wieczorek, Jaka Gašper Pečnik, 2025, objavljeni znanstveni prispevek na konferenci Povzetek: This study investigates the dynamic mechanical properties of flexible polyurethane (FPU) adhesives bonded to European beech wood (Fagus sylvatica L.) using Dynamic Mechanical Analysis (DMA) over a range of temperatures and frequencies. Samples included clear beech wood and three-layered composite (beech:FPU:beech). DMA tests were performed using a three-point bending setup at 1 Hz and 10 Hz in the temperature range from -120°C to 140°C. The results demonstrated high thermal stability and strong bonding performance of FPU adhesives on beech wood. Frequency-dependent responses varied among FPU types but resembled the behavior of solid wood at lower temperatures. This confirms the suitability of DMA for evaluating adhesive-wood composite behavior under dynamic conditions. The combination of FPU adhesives and beech wood showed potential for thermally stable and energy-dissipating bonded assemblies.
Ključne besede: dynamic mechanical analysis, FPU, beech wood
Objavljeno v DiRROS: 27.08.2025; Ogledov: 356; Prenosov: 173
Celotno besedilo (2,05 MB)
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1237. Natural exposure comparison of timber joints bonded with polyurethane adhesive in two climatic conditionsMartin Capuder, Gary M. Raftery, Weixi Wang, Zubin Karami, Boris Azinović, Andreja Pondelak, Luka Naumovski, Tomaž Pazlar, 2025, objavljeni znanstveni prispevek na konferenci Povzetek: The increased use of engineered wood in the built environment is attracting much attention because of the significant sustainable attributes. The formation of high quality reliable structural adhesive bonds is essential during the manufacture of such products. This research examines and compares the performance of bonded European beech and Radiata pine subject to natural weathering, comparing untreated, preservative treated and mineralized wood. Bonded joints were naturally weathered in Slovenia and New Zealand, respectively. The fracture energy was evaluated through Mode I fracture tests using the double cantilever beam arrangement at various ageing stages. FTIR analysis was conducted to assess chemical changes in the adhesives and wood substrate. The research provides insights into the interactions between ageing, wood species, and adhesive performance, enhancing timber structures sustainability.
Ključne besede: durability, weathering, climate, adhesive bond, mode I fracture testing
Objavljeno v DiRROS: 27.08.2025; Ogledov: 408; Prenosov: 173
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1240. Characterization of steel corrosion in alkali-activated mortars using advanced techniquesNina Gartner, Miha Hren, Tadeja Kosec, Andraž Legat, 2025, izvirni znanstveni članek Povzetek: Alkali-activated materials have emerged as a promising substitute for ordinary Portland cement (OPC) in various applications. This study explores the use of different monitoring techniques for assessing the long-term corrosion behavior of steel in alkali-activated mortars, which remains relatively understudied. Three types of alkali-activated mortars (AAMs) were prepared, based on fly ash, slag, or metakaolin as the precursor material. The corrosion of embedded steel was investigated under wetting and drying cycles with chloride-containing solution for up to one year. Two unconventional techniques were used to monitor corrosion: coupled multi-electrode array sensors (CMEA) to measure partial currents, and electrical resistance (ER) sensors to track thickness reduction. The ER sensors enabled evaluation of general corrosion rates over time, while CMEA provided insight into corrosion initiation and its spatiotemporal distribution. In addition, the corrosion damage on the embedded steel and sensors was evaluated using X-ray computed microtomography (microCT). Distinct corrosion patterns were observed depending on the precursor material: severe corrosion in metakaolin-based AAMs, localized pitting in slag-based AAMs, and moderate damage in fly ash-based AAMs. The study demonstrates the complementary value of CMEA and ER sensors and highlights the challenges of characterizing the long-term corrosion processes in these alternative binder systems.
Ključne besede: corrosion, alkali‐activated materials, coupled multi-electrode array (CMEA), electrical resistance (ER) sensor, X-ray computed microtomography (microCT), visual analysis
Objavljeno v DiRROS: 27.08.2025; Ogledov: 410; Prenosov: 291
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