Search Results (2,946)

The growing need to improve the management of end-of-life vehicle (ELV) waste and mitigate its environmental impact is a global concern. One promising approach to enhancing the recyclability of these vehicles is leveraging synergies between the automotive and construction industries as part of a circular economy strategy. In this context, ELV waste emerges as a valuable source of secondary raw materials, enabling the development of sustainable innovations that capitalize on its physical and mechanical properties. This paper aims to develop and evaluate construction industry composites incorporating waste from ELV carpets, with a focus on maintaining or enhancing performance compared to conventional materials. To achieve this, an experimental program was designed to assess cementitious composites, specifically subfloor mortars, incorporating automotive carpet waste (ACW). The results demonstrate that, beyond the physical and mechanical properties of the developed composites, the dynamic stiffness significantly improved across all tested waste incorporation levels. This finding highlights the potential of these composites as an alternative material for impact noise insulation in flooring systems. From an academic perspective, this research advances knowledge on the application of ACW in cement-based composites for construction. In terms of managerial contributions, two key market opportunities emerge: (1) the commercial exploitation of composites produced with ELV carpet waste and (2) the development of a network of environmental service providers to ensure a stable waste supply chain for innovative and sustainable products. Both strategies contribute to reducing landfill disposal and mitigating the environmental impact of ELV waste, reinforcing the principles of the circular economy. Full article

In this study, the water-repellent performance of Expanded Perlite (EP) coated with stearic acid (SA) at different coating/EP ratios (0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 1%, 2%, 3%, 4% and 5%) and the capillary water absorption and thermal conductivity behaviors of the modified insulation mortars prepared at these different coating/EP ratios were investigated experimentally. In contrast to the existing literature, experimental studies were carried out for both coated and uncoated EP particles used in mortars to which water-repellent polymers were not added, and the minimum and maximum coating amounts showing the lowest capillary water absorption and slump were determined. In addition, the sustainability of modified insulation mortars consisting of EP-coated SA was determined by sustainable thermal performance (STP). In other words, this study is the first in the literature to determine how the thermal conductivity values of these mortars may change during their use in buildings. According to the experimental results, water absorption, which is an undesirable property, decreased significantly when coated with SA, and even SA-coated expanded coarse perlite (SCP) showed almost no water-absorption behavior at coating levels above 2%. The water-repellent performance of SCP was determined to be 83.2% between 0.1% and 0.4%. In addition, for coarse mortars (MCs), the best water-repellent performance was achieved at a 5% coating/EP ratio, with a 37% reduction in the capillary water-absorption coefficient. In addition, it was found that STP values increased as the coating/EP ratio increased. In other words, modified insulation mortars became more sustainable with an increasing SA coating/EP ratio. The highest STP values were observed in Groups 2 and 4 at a 5% coating/EP ratio, with MC-5 reaching 39.27% in Group 2 and MF-5 reaching 30.30% in Group 4. The results are important from a practical/industrial point of view and from a scientific point of view. Full article

Highly integrable silicon carbide (SiC) has emerged as a promising platform for photonic integrated circuits (PICs), offering a comprehensive set of material and optical properties that are ideal for the integration of nonlinear devices and solid-state quantum defects. However, despite significant progress in nanofabrication technology, the development of SiC on an insulator (SiCOI)-based photonics faces challenges due to fabrication-induced material optical losses and complex processing steps. An alternative approach to mitigate these fabrication challenges is the direct deposition of amorphous SiC on an insulator (a-SiCOI). However, there is a lack of systematic studies aimed at producing high optical quality a-SiC thin films, and correspondingly, on evaluating and determining their optical properties in the telecom range. To this end, we have studied a single-source precursor, 1,3,5-trisilacyclohexane (TSCH, C₃H₁₂Si₃), and chemical vapor deposition (CVD) processes for the deposition of SiC thin films in a low-temperature range (650–800 °C) on a multitude of different substrates. We have successfully demonstrated the fabrication of smooth, uniform, and stoichiometric a-SiCOI thin films of 20 nm to 600 nm with a highly controlled growth rate of ~0.5 Å/s and minimal surface roughness of ~5 Å. Spectroscopic ellipsometry and resonant micro-photoluminescence excitation spectroscopy and mapping reveal a high index of refraction (~2.7) and a minimal absorption coefficient (<200 cm⁻¹) in the telecom C-band, demonstrating the high optical quality of the films. These findings establish a strong foundation for scalable production of high-quality a-SiCOI thin films, enabling their application in advanced chip-scale telecom PIC technologies. Full article

Silica-modified electrodes possess physicochemical properties that make them valuable in electrochemical sensing and energy-related applications. Although intrinsically insulating, silica thin films can selectively interact with redox species, producing sieving effects that enhance electrochemical responses. We synthesized Class I hybrid silica matrices incorporating either negatively charged poly(4-styrene sulfonic acid) or positively charged poly(diallyl dimethylammonium chloride). These hybrid films were deposited onto ITO electrodes and evaluated via cyclic voltammetry in aqueous ferrocenium solutions. The polyelectrolyte charge played a key role in the electroassisted incorporation of ferrocene: silica-PSS films promoted accumulation, while silica-PDADMAC films hindered it due to electrostatic repulsion. In situ UV-vis spectroscopy confirmed that only a fraction of the embedded ferrocene was electroactive. Nevertheless, this fraction enabled effective mediated detection of cytochrome c in solution. These findings highlight the crucial role of ionic interactions and hybrid composition in electron transfer to redox proteins, providing valuable insights for the development of advanced bioelectronic sensors. Full article

Spin transport behaviors in heavy metal/ferromagnetic insulator (HM/FI) bilayers have attracted considerable attention due to various novel phenomena and applications in spintronic devices. Herein, we investigate the planar Hall effect (PHE) in Pt/Tm₃Fe₅O₁₂ (Pt/TmIG) heterostructures at low temperatures; moment switching in the ferrimagnetic insulator TmIG is detected by using electrical measurements. Double switching hysteresis PHE curves are found in Pt/TmIG bilayers, closely related to the magnetic moment of Tm³⁺ ions, which makes a key contribution to the total magnetic moment of TmIG film at low temperature. More importantly, a magnetoresistance (MR) curve with double switching is found, which has not been reported in this simple HM/FI bilayer, and the sign of this MR effect is sensitive to the angle between the magnetic field and current directions. Our findings of these effects in this HM/rare earth iron garnet (HM/REIG) bilayer provide insights into tuning the spin transport properties of HM/REIG by changing the rare earth. Full article

Polypropylene (EPP) concrete offers advantages such as low density and good thermal insulation properties, but its relatively low strength limits its engineering applications. Waste steel fibers (WSFs) obtained during the sorting and processing of machining residues can be incorporated into EPP concrete (EC) to enhance its strength and toughness. Using the volume fractions of EPP and WSF as variables, specimens of EPP concrete (EC) and waste steel fiber-reinforced EPP concrete (WSFREC) were prepared and subjected to cube compressive strength tests, splitting tensile strength tests, and four-point flexural strength tests. The results indicate that EPP particles significantly improve the toughness of concrete but inevitably lead to a considerable reduction in strength. The incorporation of WSF substantially enhanced the splitting tensile strength and flexural strength of EC, with increases of at least 37.7% and 34.5%, respectively, while the improvement in cube compressive strength was relatively lower at only 23.6%. Scanning electron microscopy (SEM) observations of the interfacial transition zone (ITZ) and WSF surface morphology in WSFREC revealed that the addition of EPP particles introduces more defects in the concrete matrix. However, the inclusion of WSF promotes the formation of abundant hydration products on the fiber surface, mitigating matrix defects, improving the bond between WSF and the concrete matrix, effectively inhibiting crack propagation, and enhancing both the strength and toughness of the concrete. Full article

Aluminium alloy foams have been widely used due to their excellent strength-to-weight ratio, low density, and outstanding properties such as high energy absorption and effective noise and heat insulation. In this study, aluminium machining chips have been used for foam production as a potential recycling method. The process has involved solution heat treatment followed by artificial ageing. Researchers have been analysing the microhardness of both the foam and the bulk material, as well as examining their microstructures. The maximum microhardness value of the bulk material has been found to be 158 ± 2 HV1 at an ageing temperature of 175 ± 1 °C for 2 ± 0.02 h. For the foams, the highest microhardness of 150 ± 2 HV1 has been achieved after ageing at 150 ± 1 °C for 9 ± 0.02 h. Experimental planning has been carried out using Design Expert software. The optimisation process has identified 150 ± 1 °C for 2 ± 0.02 h as the optimum condition for artificial ageing. Full article

In the context of the growing need to reduce greenhouse gas emissions and to develop sustainable solutions for the construction industry, foamed geopolymers represent a promising alternative to traditional binders and insulation materials. This study investigates the thermal properties of novel low-emission, insulating geopolymer binders made from fly ash with diatomite, chalcedonite, and wood wool aiming to assess their potential for use in thermal insulation systems in energy-efficient buildings. The stability of the foamed geopolymer structure is also assessed. Measurements of thermal conductivity, specific heat, microstructure, density, and compressive strength are presented. The findings indicate that the selected geopolymer formulations exhibit low thermal conductivity, high heat capacity and low density, making them competitive with conventional insulation materials—mainly load-bearing ones such as aerated concrete and wood wool insulation boards. Additionally, incorporating waste-derived materials reduces the production carbon footprint. The best results are represented by the composite incorporating all three additives (diatomite, chalcedonite, and wood wool), which achieved the lowest thermal conductivity (0.10154 W/m·K), relatively low density (415 kg/m³), and high specific heat (1.529 kJ/kg·K). Full article

The acoustic performance of windows significantly influences evaluations of building quality, particularly in urban environments. This study presents the results of laboratory tests on the airborne sound insulation of windows with dimensions greater than those specified in ISO 10140-5:2021-10. The aim was to determine the impact of construction details and installation techniques on sound insulation, specifically R_w and R_w + C_tr values. The experimental variables included mounting methods (expansion tape versus low-pressure polyurethane foam), the presence or absence of a threshold in the lower frame, and the type of mullion (fixed versus movable). The tests involved two types of IGUs characterized by different acoustic properties. The findings indicate that the frame configuration, including threshold and mullion type, has a negligible influence on sound insulation. However, the standard method for estimating acoustic performance (EN 14351-1:2006 + A2:2017), which relies on IGU-based data, proved unreliable for modern window assemblies. The estimated values of R_w and R_w + C_tr were consistently lower than those obtained from direct laboratory measurements. These results highlight the need for verification through full-size window testing and suggest that reliance on simplified estimation procedures may lead to underperformance in real-world acoustic applications. Full article

To meet the European Green Deal targets, the construction sector must improve building thermal performance via advanced insulation systems. Eco-friendly sandwich panels offer a promising solution. Therefore, this work aims to develop and validate a new eco-friendly composite sandwich panel (basalt fibres and recycled extruded polystyrene) with enhanced multifunctionality for lightweight and energy-efficient building façades. Two panels were produced via vacuum infusion—a reference panel and a multifunctional panel incorporating phase change materials (PCMs) and silica aerogels (AGs). Their performance was evaluated through lab-based thermal and acoustic tests, numerical simulations, and on-site monitoring in a living laboratory. The test results from all methods were consistent. The PCM-AG panel showed 16% lower periodic thermal transmittance (0.16 W/(m²K) vs. 0.19 W/(m²K)) and a 92% longer time shift (4.26 h vs. 2.22 h), indicating improved thermal inertia. It also achieved a single-number sound insulation rating of 38 dB. These findings confirm the panel’s potential to reduce operational energy demand and support long-term climate goals. Full article

The study investigates the potential of enhancing gypsum board properties through the integration of hemp hurds and glass fibers. The investigation focuses on evaluating the composite material’s density, water absorption, flexural strength, compressive strength, and thermal performance. Experimental results demonstrate a reduction in gypsum composite density and improved thermal insulating properties with the introduction of hemp hurds. Water absorption, a significant drawback of gypsum boards, is mitigated with hemp hurds, indicating potential benefits for insulation efficiency. For mechanical tests, the gypsum ceiling board at approximately 5% by weight exhibits a flexural strength value exceeding the minimum average threshold of 1 MPa and the highest average compressive strength at 2.94 MPa. Thermal testing reveals lower temperatures and longer time lags in gypsum boards with 5% hemp hurds, suggesting enhanced heat resistance and reduced energy consumption for cooling. The study contributes valuable insights into the potential use of hemp hurds in gypsum-based building materials, presenting a sustainable and energy-efficient alternative for the construction industry. Full article

The insulating rod of aramid fiber-reinforced epoxy resin composites (AFRP) is an important component of gas-insulated switchgear (GIS). Under complex working conditions, the high temperature caused by voltage, current, and external climate change becomes one of the important factors that aggravate the interface degradation between aramid fiber (AF) and epoxy resin (EP). In this paper, molecular dynamics (MD) simulation software is used to study the effect of temperature on the interfacial properties of AF/EP. At the same time, the mechanism of improving the interfacial properties of three nanoparticles with different properties (insulator Al₂O₃, semiconductor ZnO, and conductor carbon nanotube (CNT)) is explored. The results show that the increase in temperature will greatly reduce the interfacial van der Waals force, thereby reducing the interfacial binding energy between AF and EP, making the interfacial wettability worse. Furthermore, the addition of the three fillers can improve the interfacial adhesion of the composite material. Among them, Al₂O₃ and CNT maintain a large dipole moment at high temperature, making the van der Waals force more stable and the adhesion performance attenuation less. The Mulliken charge and energy gap of Al₂O₃ and ZnO decrease slightly with temperature but are still higher than AF, which is conducive to maintaining good interfacial insulation performance. Full article

Mycelium-based composites (MBCs) are an emerging category of cost-effective and environmentally sustainable materials that are attracting significant research and commercial interest across various industries, including construction, manufacturing, agriculture, and biomedicine. These materials harness the natural growth of fungi as a low-energy bio-fabrication method, converting abundant agricultural by-products and waste into sustainable alternatives to energy-intensive synthetic construction materials. Their affordability and eco-friendly characteristics make them attractive for both research and commercialisation. Currently, mycelium-based foams and sandwich composites are being actively developed for applications in construction. These materials offer exceptional thermal insulation, excellent acoustic absorption, and superior fire safety compared to conventional building materials like synthetic foams and engineered wood. As a result, MBCs show great potential for applications in thermal and acoustic insulation. However, their foam-like mechanical properties, high water absorption, and limited documentation of material properties restrict their use to non- or semi-structural roles, such as insulation, panelling, and furniture. This paper presents a comprehensive review of the fabrication process and the factors affecting the production and performance properties of MBCs. It addresses key elements such as fungal species selection, substrate choice, optimal growth conditions, dehydration methods, post-processing techniques, mechanical and physical properties, termite resistance, cost comparison, and life cycle assessment. Full article

Phonolite is a fine-grained, shallow extrusive rock rich in alkali minerals and containing iron/titanium-bearing minerals. This rock is widely used as a construction material for building exteriors due to its excellent abrasion resistance and insulation properties. However, during the cutting process, approximately 70% of the rock is discarded as tailing. So, this study aims to repurpose tailings from a phonolite cutting and sizing plant into a high-alkali ceramic raw mineral concentrate. To enable the use of phonolite tailings in ceramic manufacturing, it is necessary to remove coloring iron/titanium-bearing minerals, which negatively affect the final product. To achieve this removal, dry/wet magnetic separation processes, along with flotation, were employed both individually and in combination. The results demonstrated that using dry high-intensity magnetic separation (DHIMS) resulted in a concentrate with an Fe₂O₃ + TiO₂ grade of 0.95% and a removal efficiency of 85%. The wet high-intensity magnetic separation (WHIMS) process reduced the Fe₂O₃ + TiO₂ grade of the concentrate to 1.2%, with 70% removal efficiency. During flotation tests, both pH levels and collector concentration impacted the efficiency and Fe₂O₃ + TiO₂ grade (%) of the concentrate. The lowest Fe₂O₃ + TiO₂ grade of 1.65% was achieved at a pH level of 10 with a collector concentration of 2000 g/t. Flotation concentrates processed with DHIMS achieved a minimum Fe₂O₃ + TiO₂ grade of 0.90%, while those processed with WHIMS exhibited higher Fe₂O₃ + TiO₂ grades (>1.1%) and higher recovery rates (80%). Additionally, studies on flotation applied to WHIMS concentrates showed that collector concentration, pulp density, and conditioning time significantly influenced the Fe₂O₃ + TiO₂ grade of the final concentrate. Full article

Epoxy-based nanocomposites have drawn much interest in high-voltage insulation applications due to their improved dielectric properties. The determination of the optimal nanoparticle (NP) concentration required to achieve a significant enhancement in nanocomposite dielectric properties remains a subject of ongoing research. Previous work has employed iterative experimental methodologies, often characterized by the hit-and-trial method, in attempts to find the optimal nanoparticle concentration. However, these efforts have yielded suboptimal or inconsistent results. Moreover, experimental procedures for optimizing the nanoparticle concentration require significant time and cost. This research study proposed the predictive capabilities of machine learning (ML) for the selection of the nanoparticle concentration in epoxy-based nanocomposite insulators. The authors employed a novel systematic approach in this research work, comprising dataset preparation, ML model implementation, and experimental validation. A real-time dataset with varying concentrations of NPs (TiO₂, SiO₂, Al₂O₃) was developed in the High Voltage Lab, KFUEIT, Pakistan. Several advanced machine learning models are trained on this dataset. Support Vector Regression (SVR) exhibits the highest prediction accuracy, with an R² score of 0.97. SVR predicted a breakdown voltage (BDV) of 46.26 kV, with a (w/w %) concentration of 5% TiO₂, 1.17631% SiO₂, and 3.95755% Al₂O₃. To validate the SVR prediction, a hardware prototype with predicted NP concentration is developed and tested. The experimentally measured BDV of the predicted nanocomposite sample, registering 44.72 kV, authenticates the predictive accuracy of machine learning. This work demonstrates the efficacy of machine learning as a viable and efficient alternative to traditional experimental methods for optimizing nanoparticle concentrations using a predictive approach in epoxy-based nanocomposites for high-voltage insulation applications. Full article