1. Ornate Bairdiidae (Ostracoda) in 3 dimensions : exploring carapace morphology and pore canals of Triebelina van den Bold, 1946, Nodobairdia Kollmann, 1963 and Mirabairdia Kollmann, 1963Marie-Béatrice Forel, Nathalie Poulet-Crovisier, Lidija Korat, Rosalie F. Maddocks, 2024, izvirni znanstveni članek Povzetek: Marine ostracods of the family Bairdiidae Sars, 1888 have an evolutionary history starting from the Ordovician with an explosive diversification of ornate forms during the Triassic. Representatives of the family are notoriously homeomorphic, which makes their taxonomy a major challenge of modern ostracodology. Their classification has thus been problematic since the 1970s. Here we present the first CT-scan investigation of recent and fossil ornate Bairdiidae valves in order to characterize and evaluate the taxonomic significance of unexploited characters, such as pores and pore canals. Thanks to 3D tomography, we explore the distribution of pores at the surface and the pathway of pore ca- nals within the valve wall of the recent genus Triebelina van den Bold, 1946 and the Triassic genera Nodobairdia Kollmann, 1963 and Mirabairdia Kollmann, 1963. In Triebelina indopacifica van den Bold, 1946, we describe an unexpected system of double pore canals, so far unknown in ostracods. We confirm that pore systems in Triebelina have largely intramural positions. In the Triassic Bairdiidae (Nodobairdia mammilata Kollmann, 1963 and Mirabairdia pernodosa Kollmann, 1963), we recognize simple unrimmed and massively nodular pores as well as marginal pores. Lateral normal pores of the Triassic specimens appear to be mostly in intra-solum positions. Although still exploratory and at the limits of the tomographic resolution, these observations provide new evidence to reject the formerly proposed synonymy of Triassic genera with Triebelina, which obstructed the establishment of a phylogenetic classification.
Ključne besede: ostracods, ornate Bairdiidae, morphology, normal pore canals, CT-scan, 3D analysis
Objavljeno v DiRROS: 08.03.2024; Ogledov: 127; Prenosov: 98
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2. Electrochemical corrosion tests on steel in alkali-activated materialsNina Gartner, Miha Hren, Tadeja Kosec, Andraž Legat, 2021, objavljeni znanstveni prispevek na konferenci Povzetek: One of the potential alternatives to Ordinary Portland Cement (OPC) are Alkali-Activated Materials (AAMs). The service life of reinforced concrete structures greatly depends on the corrosion resistance of embedded steel reinforcement. Due to the wide range of AAMs and their diverse properties, corrosion processes of steel in these materials are relatively unknown. Corrosion monitoring methods or their interpretations in certain cases cannot be directly transferred from the ones for OPC materials. The chemical compositions of pore solution in different AAMs influence the results of electrochemical measurements and their interpretations. Within this research, three different alkali-activated mortar mixes were prepared, based on fly ash, slag or metakaolin. Pore solutions were extracted from each mortar andchemical analysis was acquired. Different electrochemical corrosion measurements were performed on steel submerged to synthetic pore solutions. In parallel, ordinary carbon steel reinforcing bar was installed in the same types of alkali-activated mortar mixes. Specimens were exposed to wet/dry cycles with saline solution and periodic measurements of electrochemical impedance spectroscopy (EIS) were performed. Measured parameters in both systems were analysedand compared. It was concluded that electrochemical measurements in pore solutions can provide basic overview on corrosion behaviour in different AAMs environments. Periodic EIS measurements enabled monitoring of corrosion initiation and propagation on steel reinforcement in AAMs, although the information on the corrosion type is missing. Interpretation of results depends on visual analysis of corrosion damages after the end of exposure, providing information on corrosion type and intensity. The continuation of research on corrosion monitoring techniques will be performed by using Electrical Resistance (ER) sensors and Coupled Multi-Electrode Array (CMEA) sensors.
Ključne besede: corrosion, alkali-activated mortars, pore solution extraction, electrochemical corrosion techniques, visual analysis
Objavljeno v DiRROS: 22.01.2024; Ogledov: 201; Prenosov: 110
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3. The corrosion properties of steel in pore solutions obtained from alkali‐activated mortarsNina Gartner, Tadeja Kosec, Stéphane Poyet, Andraž Legat, 2023, izvirni znanstveni članek Povzetek: Alkali‐activated materials (AAMs) are considered a promising alternative to materials made from ordinary Portland cement (OPC). Other than considering the durability of the material itself, the use of AAMs for reinforced concrete elements also raises the question of steel corrosion processes in these materials, which are still relatively unknown. Three different alkali‐activated mortars were prepared for this study, based on either fly ash, slag, or metakaolin. Pore solutions were then extracted from each mortar and chemically analyzed. Electrochemical techniques were used to study the corrosion of steel in synthetic pore solutions containing varying concentrations of chlorides. In parallel, the same corrosion tests were performed in a generic pore solution representing OPC mortar. It was shown that the chemical composition differed in each pore solution tested, thus affecting the corrosion properties of the steel. The addition of chloride also had a varying effect on the corrosion properties of the steel in each type of pore solution tested. This study provided a basic overview of the corrosion behavior and mechanisms of the various AAM environments in comparison to that of OPC.
Ključne besede: alkali-aktivated materials, corrosion, electrochemical corrosion techniques, extracted pore solution
Objavljeno v DiRROS: 20.11.2023; Ogledov: 238; Prenosov: 37
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4. Corrosion performance of steel in blended cement pore solutionsMiha Hren, Tadeja Kosec, Andraž Legat, Violeta Bokan-Bosiljkov, 2019, izvirni znanstveni članek Povzetek: Blended cements might change the chemistry of the pore solution and subsequently affect the corrosion of steel in concrete. Pore solutions were extracted, analyzed and compared from mortars made of CEM I, CEM II, CEM III and CEM IV cements. Three combinations of carbonation and chloride states were studied, i.e., non-carbonated without chlorides, non-carbonated with chlorides and carbonated with chlorides. Different electrochemical and spectroscopic techniques were used to study the electrochemical properties, the type and the extent of the corrosion products, as well as the type and the extent of the corrosion damage. It was confirmed that the most corrosive environments were pore solutions extracted from the carbonated mortars with chlorides. In this environment the highest corrosion rate was observed for the CEM III pore solution, and the lowest for the CEM I. The extent and the type of corrosion products and the corrosion damage varied according to the environment.
Ključne besede: corrosion, blended cements, pore solution, mortar
Objavljeno v DiRROS: 14.09.2023; Ogledov: 292; Prenosov: 111
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5. Corrosion behavior of steel in pore solutions extracted from different blended cementsMiha Hren, Tadeja Kosec, Andraž Legat, 2020, izvirni znanstveni članek Povzetek: Mortar specimens made from four different types of cement, CEM I, CEM II, CEM III, and CEM IV, were prepared and pore solutions extracted. Three different types of exposure were studied: noncarbonated without chlorides, noncarbonated with chlorides, and carbonated with chlorides. Various electrochemical methods (linear polarization, potentiodynamic polarization measurements) were implemented to characterize the processes of corrosion on steel in these solutions. The type and extent of corrosion products were evaluated by means of various spectroscopic techniques. Specific differences in the type and extent of corrosion damage were determined and compared for each of the extracted pore solutions from the different blended cements. An attempt was made to classify these differences in comparison with the reference cement (CEM I) and in relation to the different types of exposure.
Ključne besede: corrosion, steel in pore water, blended cements, Raman Spectroscopy
Objavljeno v DiRROS: 22.08.2023; Ogledov: 272; Prenosov: 126
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7. Design of protein logic gate system operating on lipid membranesNeža Omersa, Saša Rezelj, Matic Kisovec, Marjetka Podobnik, Gregor Anderluh, 2020, izvirni znanstveni članek Ključne besede: pore-forming toxin, listeriolysin O, protein logic gates, lipid membrane, DARPin, pH
Objavljeno v DiRROS: 25.11.2020; Ogledov: 1496; Prenosov: 859
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8. KEYLINK : towards a more integrative soil representation for inclusion in ecosystem scale models : I. : review and model conceptGabrielle I. Deckmyn, Omar Flores, Mathias Mayer, Xavier Domene, Andrea Schnepf, Katrin Kuka, Kris van Looy, Daniel P. Rasse, Maria J.I. Briones, Sébastien Barot, Matty Berg, E. I. Vanguelova, Ivika Ostonen, Harry Vereecken, Laura Martinez Suz, Beat Frey, Aline Frossard, Alexei Tiunov, Jan Frouz, Tine Grebenc, Maarja Öpik, Mathieu Javaux, Alexei Uvarov, Olga Vindušková, Paul Henning Krogh, Oskar Franklin, Juan Jiménez, Jorge Curiel Yuste, 2020, izvirni znanstveni članek Povzetek: The relatively poor simulation of the below-ground processes is a severe drawback for many ecosystem models, especially when predicting responses to climate change and management. For a meaningful estimation of ecosystem production and the cycling of water, energy, nutrients and carbon, the integration of soil processes and the exchanges at the surface is crucial. It is increasingly recognized that soil biota play an important role in soil organic carbon and nutrient cycling, shaping soil structure and hydrological properties through their activity, and in water and nutrient uptake by plants through mycorrhizal processes. In this article, we review the main soil biological actors (microbiota, fauna and roots) and their effects on soil functioning. We review to what extent they have been included in soil models and propose which of them could be included in ecosystem models. We show that the model representation of the soil food web, the impact of soil ecosystem engineers on soil structure and the related effects on hydrology and soil organic matter (SOM) stabilization are key issues in improving ecosystem-scale soil representation in models. Finally, we describe a new core model concept (KEYLINK) that integrates insights from SOM models, structural models and food web models to simulate the living soil at an ecosystem scale.
Ključne besede: soil fauna, model, Soil Organic Matter, SOM, hydrology, pore size distribution, PSD, soil biota, ecosystem
Objavljeno v DiRROS: 23.09.2020; Ogledov: 1453; Prenosov: 1215
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