41. Characterizing steel corrosion in different alkali-activated mortarsNina Gartner, Miha Hren, Tadeja Kosec, Andraž Legat, 2021, original scientific article Abstract: Alkali-activated materials (AAMs) present a promising potential alternative to ordinary Portland cement (OPC). The service life of reinforced concrete structures depends greatly on the corrosion resistance of the steel used for reinforcement. Due to the wide range and diverse properties of AAMs, the corrosion processes of steel in these materials is still relatively unknown. Three different alkali-activated mortar mixes, based on fly ash, slag, or metakaolin, were prepared for this research. An ordinary carbon-steel reinforcing bar was installed in each of the mortar mixes. In order to study the corrosion properties of steel in the selected mortars, the specimens were exposed to a saline solution in wet/dry cycles for 17 weeks, and periodic electrochemical impedance spectroscopy (EIS) measurements were performed. The propagation of corrosion damage on the embedded steel bars was followed using X-ray computed microtomography (XCT). Periodic EIS measurements of the AAMs showed different impedance response in individual AAMs. Moreover, these impedance responses also changed over the time of exposure. Interpretation of the results was based on visual and numerical analysis of the corrosion damages obtained by XCT, which confirmed corrosion damage of varying type and extent on steel bars embedded in the tested AAMs.
Keywords: corrosion, alkali-activated mortars, steel reinforcement, electrochemical impedance spectroscopy, X-ray computed microtomography, visual analysis
Published in DiRROS: 05.07.2023; Views: 385; Downloads: 180
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42. Advanced method for efficient functionalization of polymers by intermediate free-radical formation with vacuum-ultraviolet radiation and producing superhydrophilic surfacesAlenka Vesel, Rok Zaplotnik, Miran Mozetič, Nina Recek, 2023, original scientific article Abstract: An efficient approach for tailoring surface properties of polymers is presented, which enables rapid modification leading to superhydrophilic properties. The approach is based on vacuum-ultraviolet radiation (VUV) pretreatment of the surface to create reactive dangling bonds. This step is followed by a second treatment using neutral oxygen atoms that react with the dangling bonds and form functional groups. The beneficial effect of VUV pretreatment for enhanced functionalization was clearly demonstrated by comparing VUV pretreatment in plasmas created in different gases, i.e., hydrogen, nitrogen, and oxygen, which differ in the intensity of VUV/UV radiation. The emission intensity of VUV radiation for all gases was measured by vacuum ultraviolet spectroscopy. It was shown that VUV has a strong influence on the treatment time and final surface wettability. A superhydrophilic surface was obtained only if using VUV pretreatment. Furthermore, the treatment time was significantly reduced to only a second of treatment. These findings show that such an approach may be used to enhance the surface reaction efficiency for further grafting of chemical groups.
Keywords: plasma treatment, vacuum-ultraviolet radiation treatment, surface functionalization, polymer polyvinyl chloride, vacuum-ultraviolet spectroscopy, vacuum-ultraviolet photons
Published in DiRROS: 06.06.2023; Views: 402; Downloads: 199
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43. Kirurško zdravljenje visoko rizičnega raka telesa materniceNina Kovačević, 2023, published scientific conference contribution Abstract: Rak materničnega telesa je najpogostejši ginekološki rak in v Sloveniji vsako leto odkrijemo približno 350 novih primerov. Večino rakov materničnega telesa predstavlja rak endometrija, ki ga delimo v dve skupini, in sicer estrogensko odvisni in estrogensko neodvisni rak endometrija. Zdravljenje je v prvi vrsti kirurško, obseg operativnega posega je določen glede verjetnosti ponovitve. Kirurškemu zdravljenju je lahko dodano obsevanje, sistemska terapija ali kombinacija obojega.
Keywords: rak maternice, ginekološki raki, ginekološka onkologija
Published in DiRROS: 30.05.2023; Views: 368; Downloads: 153
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44. Application of electrochemical methods for studying steel corrosion in alkali-activated materialsShishir Mundra, Gabriel Samson, Giulia Masi, Rebecca Achenbach, David M. Bastidas, Susana Bernal, Maria Chiara Bignozzi, Maria Criado, Martin Cyr, Nina Gartner, Stefanie von Greve‐Dierfeld, Andraž Legat, Nikoonasab Ali, John L. Provis, Michael Raupach, Gregor J. G. Gluth, 2023, original scientific article Abstract: Alkali‐activated materials (AAMs) are binders that can complement and partially substitute the current use of conventional cement. However, the present knowledge about how AAMs protect steel reinforcement in concrete elements is incomplete, and uncertainties exist regarding the application of electrochemical methods to investigate this issue. The present review by EFC WP11‐Task Force ‘Corrosion of steel in alkali‐activated materials’ demonstrates that important differences exist between AAMs and Portland cement, and between different classes of AAMs, which are mainly caused by differing pore solution compositions, and which affect the outcomes of electrochemical measurements. The high sulfide concentrations in blast furnace slag‐based AAMs lead to distinct anodic polarisation curves, unusually low open circuit potentials, and low polarisation resistances, which might be incorrectly interpreted as indicating active corrosion of steel reinforcement. No systematic study of the influence of the steel–concrete interface on the susceptibility of steel to corrosion in AAMs is available. Less common electrochemical methods present an opportunity for future progress in the field.
Keywords: alkali-aktivated materials, alkali‐activated materials, anodic/cathodic polarisation, concrete, linear polarisation resistance, open circuit potential, reinforcement corrosion, resistivity
Published in DiRROS: 29.05.2023; Views: 308; Downloads: 134
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45. Environmental acceptability of geotechnical composites from recycled materials : comparative study of laboratory and field investigationsMarija Đurić, Vesna Zalar Serjun, Ana Mladenovič, Alenka Mauko Pranjić, Radmila Milačič, Janez Ščančar, Janko Urbanc, Nina Mali, Alenka Sešek Pavlin, Janez Turk, Primož Oprčkal, 2023, original scientific article Abstract: The environmental properties of three geotechnical composites made by recycling wastes were investigated on a laboratory scale and in the field with the use of lysimeters designated for the revitalization of degraded mining sites. Composites were prepared by combining the mine waste with paper-mill sludge and foundry sand (Composite 1), with digestate from municipal waste and paper ash (Composite 2), and with coal ash, foundry slag and waste incineration bottom ash (Composite 3). The results of laboratory leaching tests proved that Composites 1 and 3 are envi- ronmentally acceptable, according to the legislative limits, as the potentially hazardous substances were immobilized, while in Composite 2, the legislative limits were exceeded. In the field lysimeters, the lowest rate of leaching was determined for optimally compacted Composites 1 and 3, while for Composite 2 the leaching of Cu was high. This study proved that optimally installed Composites 1 and 3 are environmentally acceptable for use in construction as an alternative to virgin materials, for the revitalization of degraded mining sites or, along with Composite 2, for closure operations with landfills. In this way, locally available waste streams are valorised and channelized into a beneficial and sustainable recycling practice.
Keywords: waste, recycling, lysimeter, potentiali hazardous substances, immobilization, revitalisation, environmental, open access
Published in DiRROS: 29.05.2023; Views: 345; Downloads: 253
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47. Contrasting responses of alien and ancient forest indicator plant species to fragmentation process in the temperate lowland forestsMirjana Šipek, Lado Kutnar, Aleksander Marinšek, Nina Šajna, 2022, original scientific article Abstract: Fragmentation is one of the major threats to biodiversity. In a fragmented landscape, forest specialists are losing suitable forest habitats with specific site and microclimate conditions, which results in their local extinction. Conversely, the invasion of alien species is facilitated by open forest areas and increased boundaries between forest fragments and adjacent land. We studied the effect of fragmentation in terms of fragment size impact on overall plant species richness and on selected ecologically important groups' richness, composition, and diversity. We surveyed vegetation in the interior of 47 fragments of various sizes and one unfragmented reference forest. Our results reveal that the effect of fragmentation is complex and differs for studied plant groups. Decreasing fragment size negatively affects the overall plant richness and richness of native and ancient forest indicator plants as well as their diversity, while the effect is positive for alien plants. The highest proportion of ancient forest indicator plant species and the lowest proportion of alien plants in the unfragmented forest underline the great conservation value of forest fragments. At the same time, our results reveal that large and diverse forest ecosystems are susceptible to biological invasions as well.
Keywords: forest fragment, indicator plants, invasion, diversity, habitat modification, habitat conservation
Published in DiRROS: 15.05.2023; Views: 352; Downloads: 190
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48. Sistemsko zdravljenje bolnikov s pljučnim rakom : zaviralci imunskih nadzornih točkNina Turnšek, 2023, published scientific conference contribution Abstract: Zaviralci imunskih nadzornih točk (ZINT) predstavljajo pravo revolucijo v sistemskem
zdravljenju raka pljuč in so v zadnjem desetletju korenito spremenili standardno zdravljenje
teh bolnikov. Prepričljivo dobrobit s podaljšanjem preživetja so sprva izkazali kot samostojno
zdravljenje pri bolnikih z razsejanim nedrobnoceličnim rakom pljuč (NDRP), ki je napredoval
po predhodnem zdravljenju s kemoterapijo na osnovi platine. Kmalu zatem je sledil njihov
premik v prvi red zdravljenja razsejane bolezni najprej kot samostojno zdravljenje, nato pa
še v kombinaciji s kemoterapijo na osnovi platine in tudi kot kombinirana imunoterapija
dveh ZINT. Korenito so spremenili tudi obravnavo bolnikov z NDRP v zgodnejših stadijih
bolezni, predvsem lokalno napredovale oblike, še posebej veliko obetajo v perioperativnem
obdobju. Imunoterapija z ZINT se pri raku pljuč uporablja kot monoterapija, kot kombinacija
s kemoterapijo z ali brez zaviralca angiogeneze oziroma kombinacija dveh različnih ZINT.
Keywords: pljučni rak, onkološko zdravljenje, bolniki
Published in DiRROS: 12.05.2023; Views: 345; Downloads: 76
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49. Priprava mešanice polimlečne kisline in škroba modificiranega z mlečno kislino : diplomsko deloNina Avguštin, 2022, undergraduate thesis Keywords: škrob, graftiranje, polimlečna kislina, mlečna kislina, infrardeča Fourierjeva transformacija (FT-IR), termogravimetrična analiza (TGA), optična mikroskopija, diplomsko delo
Published in DiRROS: 30.03.2023; Views: 600; Downloads: 169
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50. Stroop in motion : neurodynamic modulation underlying interference control while sitting, standing, and walkingManca Peskar, Nina Omejc, Maja Maša Šömen, Aleksandar Miladinović, Klaus Gramann, Uroš Marušič, 2023, original scientific article Abstract: There is conflicting evidence about how interference control in healthy adults is affected by walking as compared to standing or sitting. Although the Stroop paradigm is one of the best-studied paradigms to investigate interference control, the neurodynamics associated with the Stroop task during walking have never been studied. We investigated three Stroop tasks using variants with increasing interference levels – word-reading, ink-naming, and the switching of the two tasks, combined in a systematic dual-tasking fashion with three motor conditions – sitting, standing, and treadmill walking. Neurodynamics underlying interference control were recorded using the electroencephalogram. Worsened performance was observed for the incongruent compared to congruent trials and for the switching Stroop compared to the other two variants. The early frontocentral event-related potentials (ERPs) associated with executive functions (P2, N2) differentially signaled posture-related workloads, while the later stages of information processing indexed faster interference suppression and response selection in walking compared to static conditions. The early P2 and N2 components as well as frontocentral Theta and parietal Alpha power were sensitive to increasing workloads on the motor and cognitive systems. The distinction between the type of load (motor and cognitive) became evident only in the later posterior ERP components in which the amplitude non-uniformly reflected the relative attentional demand of a task. Our data suggest that walking might facilitate selective attention and interference control in healthy adults. Existing interpretations of ERP components recorded in stationary settings should be considered with care as they might not be directly transferable to mobile settings.
Keywords: Stroop task, mobile brain imaging, mobile body imaging, event-related potential, dual tasking
Published in DiRROS: 29.03.2023; Views: 422; Downloads: 269
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