131. Improved synthetic route of incorporation of nanosilicon species into phenol-formaldehyde resin and preparation of novel ZnAl-layered double-hydroxide hybrid phenol-formaldehyde resinAna Dremelj, Romana Cerc Korošec, Andreja Pondelak, Branka Mušič, 2022, izvirni znanstveni članek Povzetek: Hybrid phenol-formaldehyde (PF) resins represent one of the most important niche groups of binding systems for composites. New industrial needs, environmental requirements, and price fluctuations have led to further research on materials with enhanced mechanical and thermal properties. The preparation of novel hybrid materials can be achieved by inclusion of various elements or functional groups in the organic polymer phenolic framework. Herein, we report the synthesis and characterization of a PF-based hybrid material with different nanoscale silicone species and ZnAl-layered double hydroxide (LDH). The main goals of this study were to improve the synthetic pathways of hybrid resin, as well as to prepare granulated composite materials and test samples and determine their characterization. Added inorganic species increased the glass-transition temperature by a minimum of 8 °C, which was determined using differential scanning calorimetry (DSC). Rheological properties (melting viscosity and flow distance) of the hybrid resin were measured. The homogeneity of distribution of added species across the organic matrix was evaluated with scanning electron microscopy (SEM). With synthesized new hybrid-binding systems, we prepared different granulated composite materials and evaluated them with the measurements of rheological properties (flow curing characteristics). Tensile strength of samples, prepared from granulated composite material, improved by more than 5%. Ključne besede: phenol-formaldehyde hybrid resins, nano-SiO2, ZnAl-LDH, composites, glass-transition temperature, mechanical properties Objavljeno v DiRROS: 03.05.2023; Ogledov: 396; Prenosov: 176 Celotno besedilo (1,92 MB) Gradivo ima več datotek! Več... |
132. Leaching and geochemical modelling of an electric arc furnace (EAF) and ladle slag heapMojca Loncnar, Ana Mladenovič, Vesna Zalar Serjun, Marija Zupančič, Hans A. van der Sloot, 2022, izvirni znanstveni članek Povzetek: Old metallurgical dumps across Europe represent a loss of valuable land and a potential threat to the environment, especially to groundwater (GW). The Javornik electric arc furnace (EAF) and ladle slag heap, situated in Slovenia, was investigated in this study. The environmental impact of the slag heap was evaluated by combining leaching characterization tests of landfill samples and geochemical modelling. It was shown that throughout the landfill the same minerals and sorptive phases control the leaching of elements of potential concern, despite variations in chemical composi- tion. Although carbonation of the disposed steel slags occurred (molar ratio CO3/(Ca+Mg) = 0.53) relative to fresh slag, it had a limited effect on the leaching behaviour of elements of potential concern. The leaching from the slag heaps had also a limited effect on the quality of the GW. A site-specific case, however, was that leachates from the slag heap were strongly diluted, since a rapid flow of GW fed from the nearby Sava River was observed in the landfill area. The sampling and testing approach applied provides a basis for assessing the long-term impact of release and is a good starting point for evaluating future management options, including beneficial uses for this type of slag. Ključne besede: EAF slag, field verification, geochemical modelling, ladle slag, leaching, release prediction, steel slag heap Objavljeno v DiRROS: 28.04.2023; Ogledov: 380; Prenosov: 204 Celotno besedilo (4,37 MB) Gradivo ima več datotek! Več... |
133. Residual compressive behavior of self-compacting concrete after high temperature exposure - influence of binder materialsMarija Jelčić Rukavina, Ivan Gabrijel, Ivanka Netinger Grubeša, Ana Mladenovič, 2022, izvirni znanstveni članek Povzetek: This paper presents an experimental investigation of the compressive behavior of highstrength self-compacting concrete exposed to temperatures up to 600 C. Ten different concrete compositions were tested, in which part of the cement (by weight) was replaced by three different mineral additives (5–15% metakaolin, 20–40% fly ash and 5–15% limestone). The stress–strain curves, compressive strength, modulus of elasticity and strain at peak stress were evaluated from uniaxial compression tests. Scanning electron microscope micrographs were also taken to evaluate the damage caused by the high temperatures. A sharp decrease in mechanical properties and an increase in peak strain were observed already after 200 C for all mixes tested. The different mineral additives used in this study affected the variations of residual compressive strength by 24% and peak strain by 38%, while the variations of residual modulus elasticity were 14%. Comparing the obtained results with the recommendations for compressive strength given in regulatory code EN 1992-1-2 for high strength concrete, it can be concluded that the strength loss observed in EN 1992-1-2 at temperatures up to 400 C is too conservative. The Popovics model for the relationship between stress and strain provided a good approximation for the experimentally determined stress–strain curves at different temperatures. Ključne besede: self-compacting concrete, mineral additives, high temperatures, residual mechanical properties, open access Objavljeno v DiRROS: 28.04.2023; Ogledov: 373; Prenosov: 184 Celotno besedilo (10,67 MB) Gradivo ima več datotek! Več... |
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136. Fat mass to fat- free mass ratio and body composition in participants with chronic leg problemsMihaela Jurdana, Ana Tomažič, Boštjan Žvanut, 2022, izvirni znanstveni članek Ključne besede: fat-mass, fat-free mass, waist circumference, older adults, knee, hip Objavljeno v DiRROS: 20.04.2023; Ogledov: 345; Prenosov: 219 Celotno besedilo (494,83 KB) Gradivo ima več datotek! Več... |
137. In-depth study of tomato and weed viromes reveals undiscovered plant virus diversity in an agroecosystemMark Paul Selda Rivarez, Anja Pecman, Katarina Bačnik, Olivera Maksimović, Ana Vučurović, Gabrijel Seljak, Nataša Mehle, Ion Gutiérrez-Aguirre, Maja Ravnikar, Denis Kutnjak, 2023, izvirni znanstveni članek Povzetek: Background: In agroecosystems, viruses are well known to influence crop health and some cause phytosanitary and economic problems, but their diversity in non-crop plants and role outside the disease perspective is less known. Extensive virome explorations that include both crop and diverse weed plants are therefore needed to better understand roles of viruses in agroecosystems. Such unbiased exploration is available through viromics, which could generate biological and ecological insights from immense high-throughput sequencing (HTS) data. Results: Here, we implemented HTS-based viromics to explore viral diversity in tomatoes and weeds in farming areas at a nation-wide scale. We detected 125 viruses, including 79 novel species, wherein 65 were found exclusively in weeds. This spanned 21 higher-level plant virus taxa dominated by Potyviridae, Rhabdoviridae, and Tombusviridae, and four non-plant virus families. We detected viruses of non-plant hosts and viroid-like sequences and demonstrated infectivity of a novel tobamovirus in plants of Solanaceae family. Diversities of predominant tomato viruses were variable, in some cases, comparable to that of global isolates of the same species. We phylogenetically classified novel viruses and showed links between a subgroup of phylogenetically related rhabdoviruses to their taxonomically related host plants. Ten classified viruses detected in tomatoes were also detected in weeds, which might indicate possible role of weeds as their reservoirs and that these viruses could be exchanged between the two compartments. Conclusions: We showed that even in relatively well studied agroecosystems, such as tomato farms, a large part of very diverse plant viromes can still be unknown and is mostly present in understudied non-crop plants. The overlapping presence of viruses in tomatoes and weeds implicate possible presence of virus reservoir and possible exchange between the weed and crop compartments, which may influence weed management decisions. The observed variability and widespread presence of predominant tomato viruses and the infectivity of a novel tobamovirus in solanaceous plants, provided foundation for further investigation of virus disease dynamics and their effect on tomato health. The extensive insights we generated from such in-depth agroecosystem virome exploration will be valuable in anticipating possible emergences of plant virus diseases and would serve as baseline for further post-discovery characterization studies. Ključne besede: tomato, weed, virus, viroid, virome, virus discovery, virus diversity, phylogenetics, metagenomics, viromics Objavljeno v DiRROS: 13.04.2023; Ogledov: 622; Prenosov: 137 Povezava na datoteko |
138. Sušenje jelovih krošenj zaradi gliv povezanih s Pityokteines vorontzowiAna Brglez, Barbara Piškur, Andreja Kavčič, 2023, kratki znanstveni prispevek Ključne besede: gozdovi, varstvo gozdov, bela jelka, Abies alba, Vorontzowov jelov lubadar, Pityokteines vorontzowi, Geosmithia sp. Objavljeno v DiRROS: 24.03.2023; Ogledov: 468; Prenosov: 194 Celotno besedilo (267,85 KB) Gradivo ima več datotek! Več... |
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