1. Enhanced glass-jute epoxy hybrid composites reinforced with eggshell nanoparticles for sustainable high-performance engineering applicationsA. Ganesh Kumar, S. K. Pazhanivel, M. Arul, S. Dinesh, 2025, izvirni znanstveni članek Ključne besede: hybrid composites, glass-jute fiber, eggshell nanoparticles, sustainable reinforcement, bio-inspired nanocomposites, waste valorization
Objavljeno v DiRROS: 23.06.2025; Ogledov: 103; Prenosov: 59
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3. Liquid-copper infiltration and characterization of additively manufactured W-lattice structuresAljaž Iveković, Gokula Krishna Muralidharan, Andrei Galatanu, Guichuan Li, Kim Vanmeensel, Jef Vleugels, 2025, izvirni znanstveni članek Povzetek: Tungsten-copper (W-Cu) composites have a wide range of engineering applications, from arc-resistant electrodes and high-voltage electrical contacts to heat sinks for integrated circuits and plasma-facing components for fusion reactors. They combine high corrosion and erosion resistance, very good thermal and electrical conductivity, low thermal expansion, with good mechanical properties. However, the fabrication of such materials is limited in terms of shape complexity and the internal distribution of the individual phases. Furthermore, the dissimilar thermo-mechanical properties (melting temperature, thermal conductivity, coefficient of thermal expansion) of the constituent phases impose severe constraints on the fabrication and use of W-Cu composites. To overcome the challenges of component design and enable greater freedom in terms of composition, W-Cu composites were produced by a combination of additive manufacturing and liquid-melt infiltration (LMI). Porous W-lattice structures were manufactured by laser powder-bed fusion (LPBF) followed by infiltration with molten Cu. A series of composites was produced with Cu contents from 3 to 75 vol% and evaluated in terms of thermal, electrical, and mechanical properties. The LPBF-LMI W-Cu composites exhibited comparable thermo-mechanical properties to W-Cu materials manufactured using powder-metallurgical processing, but with an expanded composition range and shape complexity. Lower thermal expansion coefficients (4.5–5.8 × 10−6 K−1) and an improved thermal stability of the Young’s modulus, only a 27–33 GPa decline in the range 27–827 °C, were observed for all the compositions, which was ascribed to the W-phase connectivity in all the W-Cu composites, independent of the volume fraction of Cu.
Ključne besede: termomechanical properties, liquid-metal infiltration, laser powder-bed fusion, metal-matrix composites
Objavljeno v DiRROS: 07.02.2025; Ogledov: 325; Prenosov: 71
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4. Investigating the synergistic impact of freeze-thaw cycles and deicing salts on the properties of cementitious composites incorporating natural fibers and fly ashIldikó Merta, Vesna Zalar Serjun, Alenka Mauko Pranjić, Aljoša Šajna, Mateja Štefančič, Bojan Poletanovic, Farshad Ameri, Ana Mladenović, 2025, izvirni znanstveni članek Povzetek: In cold climates, concrete structures confront durability challenges due to harsh conditions. This study evaluates the effects of incorporating natural fibers, such as hemp and flax fibers (at 1 vol%), and partially replacing cement with fly ash (at 25 and 50 wt%) on the properties of cementitious composites subjected to accelerated aging under freeze-thaw cycles and deicing salts. Findings reveal that natural fibers enhance the freeze-thaw resistance, reducing deterioration (scaling) to 5-8% after 56 cycles. When mortars were subjected to accelerated freeze-thaw cycles, the compressive strength of plain mortar significantly decreased (up to 57%). However, adding natural fibers to the matrix substantially reduced its compressive strength loss. In the case of flexural strength, plain mortars experienced 33% loss, while hemp, flax, and polypropylene fiber mortars showed only 13%, 23%, and 10% losses, respectively. Furthermore, mortars experience a notable enhancement in their energy absorption capacity when reinforced with natural fibers, particularly with hemp fibers (up to 348% higher than plain mortar). Under harsh conditions, hemp and flax-reinforced mortars, with 25wt% fly ash replacement, lose the compressive strength significantly however still demonstrate an alternative to synthetic fibers in terms of flexural strength. Even with 25wt% of fly ash, mortars with natural fiber reinforcement display significantly superior energy absorption capacities compared to plain mortars (up to 48%).
Ključne besede: cementitious composites, natural fibers, freeze-thaw cycles, mechanical properties, mass loss, fly ash
Objavljeno v DiRROS: 23.12.2024; Ogledov: 554; Prenosov: 207
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5. 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: 535; Prenosov: 944
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7. Degradation and Stabilization of Polymer MaterialsBranka Mušič, Andrijana Sever Škapin, 2023, drugi znanstveni članki Ključne besede: polymer-based materials, nano, micro, and macro composites, effects on (micro) organisms and toxicity, impact on the ecosystem, mechanisms and products of accelerated aging and degradation, physical, chemical, mechanical, thermal, and morphological, analysis, biodegradability, sustainability, life cycle, renewable and recycled resources and the circular economy
Objavljeno v DiRROS: 21.12.2023; Ogledov: 1060; Prenosov: 495
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8. Remediation of contaminated soil by red mud and paper ashPrimož Oprčkal, Ana Mladenovič, Nina Zupančič, Janez Ščančar, Radmila Milačič, Vesna Zalar Serjun, 2020, izvirni znanstveni članek Povzetek: Remediation of contaminated soil can be performed by using various techniques, which must be adequately tailored for each specific case. The aim of this research is to critically evaluate the potential use of red mud and paper ash and a combination of the two as immobilization additives for the remediation of contaminated soil from one of the most polluted sites in Slovenia. The proposed procedure involves the preparation of geotechnical composites made from contaminated soil and mixed with 25 wt% of immobilization additives and an optimal quantity of water to achieve consistency, at which maximum compaction according to the Proctor Compaction Test procedure can be achieved. The results reveal a positive, time-dependent trend for the immobilization of potentially toxic elements in the composite with paper ash, because of the formation of the new hydration products with potentially toxic elements. In a composite containing only red mud, potentially toxic elements were immobilized by sorption mechanisms with no general time-dependent trends. The composite with a combination of additives demonstrates the remediation characteristics of both red mud and paper ash. Using this approach excavated contaminated soil, red mud and paper ash can be successfully recycled in the proposed composites, which can be beneficially used in situ for rehabilitation of contaminated sites. Nevertheless, mobilization of some potentially toxic elements at high pHs may represent a limiting factor and has to be taken into the consideration when a combination of red mud and paper ash is used as immobilization additive.
Ključne besede: red mud, paper ash, contaminated soil, potentially toxic elements, geotechnical composites
Objavljeno v DiRROS: 31.08.2023; Ogledov: 1240; Prenosov: 949
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9. Antifungal effect of polymethyl methacrylate resin base with embedded Au nanoparticlesIvan Marić, Anamarija Zore, Franc Rojko, Andrijana Sever Škapin, Roman Štukelj, Aleksander Učakar, Rajko Vidrih, Valentina Veselinović, Marijan Gotić, Klemen Bohinc, 2023, izvirni znanstveni članek Povzetek: Full and partial restorations in dentistry must replicate the characteristics of the patient’s natural teeth. Materials must have good mechanical properties and be non-toxic and biocompatible. Microbes, which can form biofilms, are constantly in contact with restorations. In this study, we investigate how well Candida albicans adheres to a polymethyl methacrylate (PMMA) resin base with gold (Au) nanoparticles. We synthesized Au nanoparticles and characterized them. The average size of Au nanoparticles embedded in PMMA was 11 nm. The color difference ∆E between PMMA and PMMA/Au composites was 2.7 and was still esthetically acceptable to patients. PMMA/Au surfaces are rougher and more hydrophilic than pure PMMA surfaces, and the isoelectric point of both types of surfaces was 4.3. Above the isoelectric point, PMMA/Au surfaces are more negatively charged than PMMA surfaces. The added Au nanoparticles decreased the tensile strength, while the hardness did not change significantly. Adhesion measurements showed that PMMA surfaces modified with Au nanoparticles reduced the extent of microbial adhesion of Candida albicans.
Ključne besede: fungal adhesión, C. albicans, polymethyl methacrylate resin, Au, surface properties, composites
Objavljeno v DiRROS: 24.07.2023; Ogledov: 1082; Prenosov: 526
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10. Impact of metakaolin on mechanical performance of flax textile-reinforced cement-based compositesFilip Majstorović, Václav Sebera, Maruša Mrak, Sabina Dolenec, Marco Wolf, Laetitia Sarah Jennifer Marrot, 2022, izvirni znanstveni članek Povzetek: This study presents research on the effect of Portland cement (PC) replacement with metakaolin on the mechanical behavior of flax textile-reinforced cementitious matrices (TRCM). The composition of cementitious matrices and in-situ flax fibres was determined using X-ray diffraction and thermogravimetric analysis, while the reinforcement efficiency of the textile and mechanical behavior of TRCMs was investigated by three-point bending tests and finite element analysis. High amounts of PC replacement with metakaolin provided a calcium hydroxide-free environment, more suitable for the natural fibres, to avoid their degradation and embrittlement and, thus, significantly contribute to the ductility of the cement-based composite material.
Ključne besede: textile-reinforced concrete (TRC), flax textile, natural fibres, finite element, metakaolin, cement-based composites, open access
Objavljeno v DiRROS: 22.05.2023; Ogledov: 1063; Prenosov: 534
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