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Povzetek: The present study propounds development of an artificial sand, with a prime aim of exploring a potential substitute for natural river sand. The artificial sand, named F-Slag sand, within the particle size range of 4.75 − 0.075 mm, is developed with the combined use of fly ash (FA) and ground granulated blast furnace slag (GGBS) as binder solids (BS) blended in proportions of 90:10, 80:20, 70:30, 60:40, and 50:50. Pelletization, by employing a custom designed disc pelletizer equipment, and geopolymerization, a process of binding and bonding of FA and GGBS particles to form sand size fractions, techniques are adopted to synthesize F-slag sand. Pelletizer speed of 15 rpm, pelletization duration of 10 min, and alkali activator solution to BS ratio of 0.06 are found optimal to produce the sand. A comprehensive micro/meso-analysis, including 3D computed tomography scan, scanning electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller analysis, and Fourier transform infrared spectroscopy are performed on F-slag sand and attempts are made to interpret macro-applications of it. Demonstrably, the synergistic use of GGBS and FA has completely alleviated the need for elevated curing of sand. The gradational analysis revealed that more than 90% of BS are converted into sand size fractions (4.75 − 0.075 mm). F-slag sand exhibited specific gravity of 2.1, water absorption of 17%, permeability 4.2 × 10− 3 cm/sec, angle of internal friction of 38°, and crushing value of 14.8%. In comparison, river sand showed 2.6, 4%, 3.6 × 10− 3 cm/sec, 39° and 6.3% respectively. The loose and compacted bulk densities of F-slag sand are measured at 698 and 991 kg/m3, which are significantly lower vis-à-vis of river sand (1546 and 1728 kg/m3). Micro-analysis confirms dense, well-bonded particles with meso–macroporous connectivity, indicating enhanced mechanical stability and durability. Moreover, leaching and environmental risk analysis affirms that F-Slag sand poses no ecological threat. The outcome of the study, proposition of a novel construction material, elucidates that F-slag sand could be a potential substitute for river sand in building (concrete, mortar, plastering, lightweight structures), mining (mine backfilling) and environmental (drainage & filter) applications.
Ključne besede: F-Slag sand, geopolymer-assisted pelletization, artificial fine aggregates, fly ash-slag synergy, micro-meso scale characterization, disc pelletizer
Objavljeno v DiRROS: 23.06.2026; Ogledov: 201; Prenosov: 195
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Ključne besede: abaca-E-glass, bamboo-derived activated carbon nanofiller, characterization, fiber volume fraction
Objavljeno v DiRROS: 22.06.2026; Ogledov: 178; Prenosov: 126
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Povzetek: The development of electrocaloric (EC) elements for cooling technologies has progressed by integrating the EC layers onto various substrates. However, a precise understanding of heat losses on direct characterization methods is still lacking, particularly in the infrared (IR) camera method. In this work, we perform numerical simulations on EC film structures to benchmark the substrate influence on the cooling output of the structure for characterization purposes. Substrates with low thermal effusivity (≤3 kW ▫$s^{1/2} m^{−2} K^{−1}$▫) exhibit minimal influence on the output of films. Simulations were also performed to investigate the impact of EC film and black-paint coating thicknesses on the correction factor for IR characterization methods. A single-digit correction factor can be achieved if the EC film is thicker than the coating. Our results offer a roadmap for designing EC structures for cooling at the micro-to-nano scales.
Ključne besede: simulation in materials science, materials characterization techniques, films, IR thermography, thin-film coatings, electrocaloric elements
Objavljeno v DiRROS: 03.06.2026; Ogledov: 218; Prenosov: 299
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Povzetek: Cucumber mosaic virus (CMV) causes significant economic losses and threatens the sustainable production of many important crops. This study represents the first analysis of CMV genetic diversity and population structure in Serbia, based on all five ORFs from nineteen isolates collected across various hosts and regions. Results of molecular and population genetic investigations revealed high genetic diversity and the presence of numerous genetic variants. Phylogenetic analyses showed that isolates from all three subgroups exist in Serbia, with IA being the most prevalent and IB occurring at the 1a gene only. Although findings indicate that majority of the observed variation arises from differences between subgroups, intra-subgroup fixed polymorphisms were also identified. Notably, both recombinants and reassortants were detected, indicating dynamic genetic exchange within the population. Recombination between subgroups IA and II was confirmed in both RNA 2 (II-IA,II-II,II and IB-IA,II-IA,IA) and RNA 3 segments (IA-IA,IA-IA,II), with recombination in the RNA 2 segment being predominant. Additionally, both types of reassortment, including IA/IB (IB-IA,IA-IA,IA) and IA/II (II-IA,IA-II,II) reassortants, were recorded. Moreover, we uncover a novel reassortant/recombinant variant (IB-IA,II-IA,IA) in the natural CMV population. Finally, results of a neutrality test across all five loci suggest demographic effects consistent with population size expansion following bottleneck events during host plant infection. This study provides the first molecular insight into CMV population structure in Serbia, offering new insights into the regional diversity and evolution of the virus. By identifying recombinant and reassortant CMV isolates circulating in Serbia, this work reveals previously unrecognized evolutionary processes shaping CMV populations in the region. These findings fill a significant geographic gap in CMV research in Western Balkans and contribute to a broader understanding of CMV evolution, diversification, and population dynamics globally.
Ključne besede: CMV, genetic diversity, molecular characterization, population genetic parameters, recombination and reassortment
Objavljeno v DiRROS: 02.03.2026; Ogledov: 439; Prenosov: 271
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Povzetek: Each year, over one billion cubic meters of sediments are dredged from ports and inland water bodies to maintain navigability and ensure infrastructure safety, creating significant landfill and environmental challenges. Dredged sediments are typically characterized by high moisture content, low bearing capacity, and limited shear strength. Their sustainable reuse requires effective stabilization and remediation strategies. Recent advancements in soil stabilization have increasingly focused on sustainable bio-binders, particularly biopolymers, due to their ecofriendly properties. This study evaluates the effectiveness of four biopolymers, namely calcium alginate (AL), chitosan (CH), xanthan gum (XA), and guar gum (GG) as sustainable bio-binders for improving dredged sediments from the Port of Koper, Slovenia. Mechanical testing demonstrated that 1 wt% XA, AL, and CH increased unconfined compressive strength by 40 %, 29 %, and 10 %, respectively. Direct shear tests revealed that AL and XA increased cohesion by 52 % and 104 %, respectively, while reducing the friction angle by 4◦ In contrast, CH and GG enhanced both cohesion (by 81 % and 37 %, respectively) and the friction angle (by 1◦ in each case). Consolidation characteristics were also improved, with reduced settlement under normal load. Microstructural analysis identified the formation of biopolymer matrices including fibrous networks, gel films, and particle clusters that explain the mechanical improvements. The findings confirm that biopolymer stabilization is a viable technique to convert dredged marine sediments into engineered materials, minimizing landfill disposal, and supporting the transition to more sustainable construction practices.
Ključne besede: dredged sediment, biopolymer, stabilization, mechanical characterization
Objavljeno v DiRROS: 13.01.2026; Ogledov: 586; Prenosov: 379
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