1. Recycled red mud as an useful geotechnical materialPrimož Pavšič, Marija Đurić, Mateja Košir, Alenka Mauko Pranjić, Ana Mladenovič, Primož Oprčkal, Sara Seršen, Vesna Zalar Serjun, 2024, objavljeni znanstveni prispevek na konferenci Povzetek: Red mud (RM) is an extractive waste from Bayer process in alumina production. The most conventional methods of RM disposal are tailing dams, or dry storage,both of which raiseenvironmental concerns due to the high alkalinity of RMandthe presence and leaching of potentially hazardous elements (PTEs).Due to its fine-grained nature and poor mechanical properties, as well as leaching of potentially hazardous substances, RM cannot be used by itself. Properties of the RM can be improved, by mixing it with hydraulic or pozzolanic binders, such as calcareous ashes or steelmaking slag, to produce mechanically stable and durable composites for earthworks. On the other hand, RMcan also serve as an immobilization additive for remediation of contaminated soils.Two different approaches for useful utilization of RMare presented based on results of laboratory research and a real case study, opening of new possibilities for conserving natural resources and reducing environmental hazards of RM deposits. Ključne besede: red mud, recycling, geotechnical composites, environment Objavljeno v DiRROS: 30.10.2024; Ogledov: 131; Prenosov: 50 Celotno besedilo (8,18 MB) Gradivo ima več datotek! Več... |
2. CFD-based analysis of deviations between thermocouple measurements and local gas temperatures during the cooling phase of compartment firesFlorian Put, Andrea Lucherini, Ruben Van Coile, Bart Merci, 2024, izvirni znanstveni članek Povzetek: Data from thermocouple (TC) measurements play a pivotal role in fire safety science and engineering studies. It is well-known that there are deviations from the actual local gas temperature and many studies have led to the development of correction factors. The present study focuses on these deviations inside compartments through a systematic series of CFD simulations, performed with Fire Dynamics Simulator (FDS), version 6.8.0. A canonical cubic box is used as geometry. This allows for the demonstration of the impact of the presence of smoke, with variable optical thickness, on the TC data as retrieved from FDS. Significant differences are observed between TC measurements and local gas temperatures. Corrections as developed for TC measurements in open atmospheres cannot be readily applied in compartment configurations, where smoke properties change both spatially and temporally. Ključne besede: thermocouple measurements, CFD simulations, heat transfer, compartment fires, cooling, fire dynamics, FDS Objavljeno v DiRROS: 28.10.2024; Ogledov: 95; Prenosov: 22 Povezava na datoteko |
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5. Seepage detection using passive temperature measurements by fiber optic DTSYaser Ghafoori, 2024, drugi znanstveni članki Povzetek: This article is an extended abstract of the doctoral dissertation “Optimization of early seepage detection in embankments using a distributed temperature system based on fiber optic sensing” [1]. Distributed Temperature Sensors (DTS) measure temperature precisely with high spatial resolution, enabling seepage flow detection through the interpretation of temperature measurement. Active DTS measurement which introduces heat into the soil to monitor its dissipation, has been extensively studied for seepage detection. However, the potential of passive measurement, which measures natural soil temperature, for seepage detection demands further exploration. The doctoral research investigated the capability of passive DTS measurements for seepage detection. The findings show that passive DTS detects very small temperature variations as a result of the seepage flow. Additionally, the results offer valuable insights into the coupled hydro-thermal behavior and the influence of seepage on heat transfer. The thesis classified and compared different techniques for temperature data calibration and interpretation. Furthermore, an interpretation approach based on numerical simulation and a fully dynamic calibration technique was developed. Ključne besede: optical fiber DTS, soil, emperature, seepage Objavljeno v DiRROS: 16.10.2024; Ogledov: 129; Prenosov: 41 Celotno besedilo (155,89 KB) Gradivo ima več datotek! Več... |
6. Crack size in coating and moisture problems comparing thermally modified and native spruce window frame profiles using hygrothermal simulationGregor Vidmar, Rožle Repič, Boštjan Lesar, Miha Humar, 2024, izvirni znanstveni članek Povzetek: Fungal growth and degradation of wood may be caused by damage in the surface coating. The larger the cracks, the greater in principle the possibility of moisture-induced problems. Measuring basic unknown material parameters and employing hygrothermal simulations, the suitability and the maximum acceptable vertical crack size in the surface coating for a given bottom window profile made of thermally modified (TM) spruce(wood) with that made of native spruce were compared for location Ljubljana. Validation with the field test data was the second objective of the respective research. The average calculated maximum moisture content in TM spruce is about 4% (kg/kg) lower than that of native spruce. The 3 mm wide crack in the surface coating of a window frame made of native spruce is of the highest concern, whereas a 9 mm wide crack in the coating of a TM spruce profile is still acceptable. As far as moisture content is concerned in our study the TM spruce window frames were proved to be significantly more suitable for installation than the corresponding frames made of native Norway spruce. It was shown that isopleth, VTT and biohygrothermal models for mould growth do not properly capture the comparison between both materials, mainly because they classify both in the same material class/substrate category and they do not consider the material moisture content. Ključne besede: hygrothermal simulations, mould growth modelling, cracks in surface coating, thermally modified wood, wooden window frame Objavljeno v DiRROS: 16.10.2024; Ogledov: 117; Prenosov: 331 Celotno besedilo (1,48 MB) Gradivo ima več datotek! Več... |
7. Influence of the oxidizing technique on the biocompatible and corrosion properties of Ti6Al4V in a physiological environmentMirjam Bajt Leban, Tadeja Kosec, Aleksandra Kocijan, Marjetka Conradi, Ita Junkar, Janez Kovač, 2025, izvirni znanstveni članek Povzetek: This work aims to evaluate the corrosion and biocompatibility properties of oxide films generated on Ti6Al4V alloys using both traditional and novel methods. Oxide films were generated by anodization and plasma treatment to achieve a blue surface finish. The oxide films were then characterized and compared to a native film formed on the Ti6Al4V.
Electrochemical tests, incorporating potentiodynamic tests and electrochemical impedance spectroscopy, were employed to define the electrochemical resistance of oxides in an environment simulating biological exposure. In vitro tests were conducted to study ion release and biocompatible properties over a 6-week period of exposure to a 0.9 wt% NaCl solution, at body temperature. Various spectroscopic techniques, including ToF-SIMS, XRD, and Raman analysis, were used to study the structure and chemistry of the oxide films. The sub-surface layer was analysed by microstructural investigation.
The type of oxidation was found to have a key influence on the oxide composition, especially with respect to the depth distribution of the individual alloy elements through the oxide film. The oxidation process determines which of the alloying elements are released into the environment, as a result of the corrosion reactions. Ključne besede: oxide film, biocompatibility, surface characterization, ion release, simulated body fluid Objavljeno v DiRROS: 16.10.2024; Ogledov: 131; Prenosov: 170 Celotno besedilo (8,67 MB) Gradivo ima več datotek! Več... |
8. Fotokatalitski heterostrukturirani nanomateriali za izkoriščanje sončne energije : zaključno poročilo o rezultatih raziskovalnega projektaAndrijana Sever Škapin, Peter Nadrah, Miran Gaberšček, 2024, elaborat, predštudija, študija Ključne besede: fotokataliza, heterostrukture, TiO2-CeO2, TiO2-Cu, sokatalizator, photocatalysis, heterostructures, co-catalyst Objavljeno v DiRROS: 14.10.2024; Ogledov: 189; Prenosov: 0 Gradivo ima več datotek! Več... |
9. Comparing the effects of pristine and UV–VIS aged microplastics : behavioural response of model terrestrial and freshwater crustaceansPrimož Zidar, Dana Kühnel, Andrijana Sever Škapin, Tina Skalar, Damjana Drobne, Luka Škrlep, Branka Mušič, Anita Jemec Kokalj, 2024, izvirni znanstveni članek Povzetek: Physico-chemical properties of microplastics (MPs) change during weathering in the environment. There is a lack of knowledge about the effects of such environmentally relevant MPs on organisms. We investigated: 1) the physico-chemical changes of MPs due to UV–VIS weathering, and 2) compared the effect of pristine and aged MPs on the behaviour of the water flea Daphnia magna and terrestrial crustacean Porcellio scaber. Dry powders of MPs were produced from widely used polymer types: disposable three-layer polypropylene (PP) medical masks (inner, middle and outer), polyester textile fibres, car tires and low-density polyethylene (LDPE) bags and were subjected to accelerated ultraviolet–visible (UV–VIS) ageing. Our results show that the extent of transformation depends on the type of polymer, with PP showing the most changes, followed by LDPE, textile fibres and tire particles. Obvious fragmentation was observed in PP and textile fibres. In the case of PP, but not polyester textile fibres, changes in FTIR spectra and surface properties were observed. Tire particles and LDPE did not change in size, but clear changes were observed in their FTIR spectra. Most MPs, aged and pristine, did not affect the swimming of daphnids. The only effect observed was a significant increase in path length and swimming speed for the pristine tire particles when the recording was done with particles remaining in the wells. After transfer to a clean medium, this effect was no longer present, suggesting a physical rather than chemical effect. Similarly, woodlice showed no significant avoidance response to the MPs tested, although there was a noticeable trend to avoid soils contaminated with pristine polyester textile fibers and preference towards the soils contaminated with aged MP of the middle mask layer. Overall, the apparent changes in physico-chemical properties of MPs after accelerated ageing were not reflected in their effects on woodlice and daphnids. Ključne besede: Daphnia magna, Porcellio scaber, polyethylene, polypropylene, weathering, FTIR Objavljeno v DiRROS: 08.10.2024; Ogledov: 166; Prenosov: 1432 Celotno besedilo (5,54 MB) Gradivo ima več datotek! Več... |
10. Unutarnja okolina renoviranih ureda opremljenih stropnim isijavajućim pločamaSabina Jordan, Jože Hafner, Tilmann E. Kuhn, Andraž Legat, Martina Zbašnik-Senegačnik, 2016, izvirni znanstveni članek Povzetek: U radu se ocjenjuje unutarnja okolina renoviranih ureda koji su, kao pokusni primjer,opremljeni naprednim stropnim isijavajućim pločama koje se primjenjuju za grijanje i hlađenje. Obavljene su opsežne analize na bazi raznih nizova stvarnih mjerenja kako bi se ocijenila djelotvornost i prikladnost predložene koncepcije za adaptiranje prostora. Ustanovljeno je da čitav sustav za temperiranje uredskih prostora funkcionira na prikladan način, te da raspon unutarnjih temperatura zraka omogućava postizanje najviše razine udobnosti. Objavljeno v DiRROS: 16.09.2024; Ogledov: 154; Prenosov: 103 Celotno besedilo (499,25 KB) Gradivo ima več datotek! Več... |