1. Boosting copper biocidal activity by silver decoration and few-layer graphene in coatings on textile fibersDanaja Štular, Nigel Willy Van de Velde, Ana Drinčić, Polona Kogovšek, Arijana Filipić, Katja Fric, Barbara Simončič, Brigita Tomšič, Raghuraj S. Chouhan, Sivasambu Bohm, Suresh Kr. Verma, P.K. Panda, Ivan Jerman, 2023, izvirni znanstveni članek Povzetek: The outbreak of the Coronavirus disease 2019 (COVID-19) pandemic has highlighted the importance of developing antiviral surface coatings that are capable of repelling pathogens and neutralizing them through self-sanitizing properties. In this study, a novel coating design based on few-layer graphene (FLG) is proposed and silver-decorated micro copper flakes (CuMF) that exhibit both antibacterial and antiviral properties. The role of sacrificial anode surfaces and intrinsic graphene defects in enhancing the release of metal ions from CuMF embedded in water-based binders is investigated. In silico analysis is conducted to better understand the molecular interactions of pathogen-repelling species with bacterial or bacteriophage proteins. The results show that the optimal amount of CuMF/FLG in the coating leads to a significant reduction in bacterial growth, with reductions of 3.17 and 9.81 log for Staphylococcus aureus and Escherichia coli, respectively. The same coating also showed high antiviral efficacy, reducing bacteriophage phi6 by 5.53 log. The antiviral efficiency of the coating is find to be doubled compared to either micro copper flakes or few-layer graphene alone. This novel coating design is versatile and can be applied to various substrates, such as personal protective clothing and face masks, to provide biocidal activity against both bacterial and viral pathogens.
Ključne besede: antibacterial, antiviral, copper micro flakes, few-layer graphene, pathogen-repelling coating
Objavljeno v DiRROS: 16.12.2025; Ogledov: 99; Prenosov: 48
 Celotno besedilo (2,95 MB)
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2. Numerical modelling of air-induced drag reduction allowing the transition between bubbly, air layer and mixed regimesBenjamin Krull, Kasper Bilde, Christian Kringel, Richard Meller, Matej Tekavčič, Filotas Tziaros, 2026, izvirni znanstveni članek Povzetek: Air lubrication can reduce the frictional resistance of ships, leading to significant fuel cost savings. However, the performance of air lubrication systems varies considerably, depending on the operating conditions. Complex gas morphologies play a crucial role here but are difficult to predict. Such a variety of morphologies (bubbly flow, air layers, or mixed regimes) requires morphology-adaptive methods, such as MultiMorph. This method allows for multiple morphologies of a given phase, including the transfer between them. The injection of gas can result in air bubbles, air layers, or a mixed regime, based on local transfer mechanisms. The ability to predict these morphologies is a distinctive feature of this method. Alternative methods prescribe a specific regime a priori, and do not allow a transition. To assess the suitability of MultiMorph for air lubrication problems, two geometries with different complexities are considered. The first test validates the method against flat plate experiments. Various water velocity and gas flow rate combinations were considered to investigate their influence on gas morphology and the associated drag reduction. The second case features a three-dimensional ship hull geometry with two bubble injectors to test the applicability of the method to a more complex scenario, including a curved geometry. The method performs well in both test cases and qualifies as a useful tool for numerical investigations of air lubrication phenomena.
Ključne besede: air lubrication, air layer, gas injection, bubbly flow, drag reduction, numerical modelling
Objavljeno v DiRROS: 12.12.2025; Ogledov: 143; Prenosov: 60
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3. Investigating the thermal penetration in structural timber elements exposed to natural firesAndrea Lucherini, Vladimír Mózer, 2025, objavljeni znanstveni prispevek na konferenci Povzetek: This study investigates fire-induced charring and thermal penetration in structural timber elements exposed to natural fire conditions, with a focus on the critical role of the cooling phase. A simplified 1D heat transfer model, based on Eurocode 5 temperature-dependent material properties, is implemented to simulate the thermal response of timber members subjected to Eurocode parametric fire curves. The analysis quantifies the char depth (300 °C isotherm) and the zero-strength layer, using both temperature-based (80-300 °C and 120-300 °C) and reduced mechanical properties approaches (tension and compression). Results show that, while the char depth predominantly develops during the heating phase, the zero-strength layer continues to grow during cooling, often reaching a thickness comparable to the char layer. The effective char depth (char depth + zero-strength layer) typically reaches its maximum towards the end of the cooling phase, representing the most critical condition for load-bearing capacity. The most severe conditions arise in low ventilation and high fuel load scenarios, characterised by long-duration fires rather than the highest temperatures. The findings highlight the need to explicitly consider the cooling phase in performance-based fire design for timber structures.
Ključne besede: timber structures, fire safety, charring, zero-strength layer, cooling
Objavljeno v DiRROS: 16.07.2025; Ogledov: 406; Prenosov: 271
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4. Alumina and hafnia thin films deposited by atomic layer deposition at different temperatures on biomedical stainless steel and titaniumIvan Spajić, Sandra Drev, Urška Trstenjak, Ingrid Milošev, 2025, izvirni znanstveni članek Povzetek: Alumina and hafnia films produced by the atomic layer deposition were applied to commercially pure Ti and stainless steel 316L specimens for protection under simulated human body conditions. The ALD films were deposited at 180 °C and 260 °C to determine how the deposition temperature affect the films' protective properties. Surface analysis of the ALD films included scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The barrier properties were tested electrochemically using potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) techniques in a simulated body solution at 37 °C. Alumina thin films showed substantial barrier properties, but after 30 days of immersion, the alumina dissolved regardless of the deposition temperature. EIS tests themselves promoted the dissolution of alumina. In contrast, the barrier properties of hafnia depended significantly on deposition temperature. Hafnia deposited at 180 °C exhibited substantial protective properties and remarkable stability over an extended immersion period. However, when deposited at 260 °C hafnia films showed strong protection at the outset, but after a few days of immersion, they lost their protective ability due to porosity. The key factors affecting the barrier properties of ALD hafnia films were the proportion of the crystalline phase and how crystallites formed.
Ključne besede: thin films, atomic layer deposition, titanium alloys, biomedical steel, medical implants
Objavljeno v DiRROS: 15.07.2025; Ogledov: 542; Prenosov: 297
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5. The effect of pore sealing in a multilayer ▫Si–O–Zr/Al_2O_3▫ coating designed to protect aluminium from corrosionPeter Rodič, Barbara Kapun, Ingrid Milošev, 2023, izvirni znanstveni članek Povzetek: This study deals with the combination of two corrosion protection strategies for aluminium: barrier protection (provided by a 3.8 μm thick hybrid sol–gel coating) and aluminium pore sealing via the use of a 100 nm thick layer of aluminium oxide. A Si–O–Zr hybrid sol–gel coating (TMZ) was synthesised by combining two separately prepared sols (i) tetraethyl orthosilicate and 3-methacryloxypropyl trimethoxysilane and (ii) zirconium(IV) n-propoxide chelated with methacrylic acid. The synthesis of the Si–O–Zr hybrid sol–gel was evaluated at various stages using real-time infrared spectroscopy. A 100 nm thick Al2O3 film was prepared via thermal atomic layer deposition at 160 °C using trimethyl aluminium and water as precursors. The coating and film properties were assessed via focused ion beam/scanning electron microscopy coupled with energy-dispersive X-ray spectrometry. Sealing with the Al2O3 film did not affect the microstructure and composition of the underlying sol–gel coating. The coating’s corrosion performance in 0.1 M NaCl solution was evaluated using electrochemical impedance spectroscopy. Compared to individual coatings, the multilayer TMZ/Al2O3 coating ensured prolonged (more than three weeks) durable corrosion protection for the aluminium. The impedance magnitude increased by two orders compared to the uncoated substrate (|Z|10 mHz from 16 kΩ cm2 to almost 830 MΩ cm2). Thus, the pore sealing of the sol–gel coating using an ALD alumina film produced a protective multilayer coating system, with |Z|10 mHz remaining above 5 MΩ cm2 after four weeks in NaCl solution.
Ključne besede: aluminum, corrosion, hybrid sol-gel, atomic layer deposition, pore sealing
Objavljeno v DiRROS: 29.04.2025; Ogledov: 756; Prenosov: 343
Celotno besedilo (11,89 MB)
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6. Application of atomic force microscopy in preparing Ni-Al layer using a two-stage processNingning Li, Zhenjie Hao, Lei Xu, Xi Chen, Jin Peng, Leyu Wei, Mingqi Tang, Yuping Tong, Zicheng Ling, Yimin Li, 2025, izvirni znanstveni članek Ključne besede: Ni-Al layer, atomic force microscopy, nickel layer, morphology
Objavljeno v DiRROS: 24.04.2025; Ogledov: 572; Prenosov: 334
Celotno besedilo (1,62 MB)
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7. Growth manipulation in electrodeposition of compact and mesoporous electron transport layers for enhanced efficiency and stability in carbon-based perovskite solar cellsTecush Mohammadi, Dimitris A. Chalkias, Nigel Willy Van de Velde, Andrej Race, Elias Stathatos, Boštjan Genorio, Blaž Likozar, Ivan Jerman, 2025, izvirni znanstveni članek Ključne besede: perovskite solar cell, electron transport layer, TiO2 electrodeposition, compact layer, mesoporous layer, photovoltaic performance
Objavljeno v DiRROS: 03.03.2025; Ogledov: 583; Prenosov: 314
Celotno besedilo (2,37 MB)
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8. Practical insights and advances in concrete pumpingDaniil Mikhalev, Ana Brunčič, 2024, izvirni znanstveni članek Povzetek: This technical letter gives a concise overview of the state-of-the-art in concrete pumping. It outlines the different pump systems, briefly describes the general flow behavior of concrete in pipes, and addresses the main challenges of pumping. It also elaborates upon factors influencing the pumping behavior and how to control the pumping process.
Ključne besede: rheology, quality control, pressure, concrete, pumping, lubrication layer
Objavljeno v DiRROS: 18.02.2025; Ogledov: 658; Prenosov: 388
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10. Predicting the effective char depth in timber elements exposed to natural fires, including the cooling phaseAndrea Lucherini, Daniela Šejnová Pitelková, Vladimír Mózer, 2023, objavljeni znanstveni prispevek na konferenci Povzetek: This paper presents a numerical study on the effect of the heating and cooling phases on the reduction of the effective cross-section of timber elements, in particular on the evolution of the char depth (300°C isotherm) and zero- strength layer. An advanced calculation method based a finite-difference heat transfer model is compared to the simplified approach suggested by Eurocode 5. For the heating phase, defined as the standard fire curve (ISO 834), the simplified Eurocode 5 method generally provides more conservative char depths, while the zero-strength layer is under-predicted. Nevertheless, the values of effective char depth are comparable. Including the cooling phase evidences that, during this phase, the heat wave penetration leads to a significant increase in the char depth and zero-strength layer. Particularly, this increase directly depends on the fire cooling rate: a slower cooling phase further reduces the effective cross-section of timber members. As a result, this research highlights how the heat wave penetration during the fire cooling phase can significantly reduce the load-bearing capacity of timber elements.
Ključne besede: timber structures, fire safety, heat transfer, charring, zero-strength layer, cooling
Objavljeno v DiRROS: 14.01.2025; Ogledov: 833; Prenosov: 427
Celotno besedilo (4,18 MB)
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