Search Results (119)

In this work, a flexible and sustainable radar-absorbing material (RAM) based on porous carbon derived from raw Kraft black liquor was developed. The porous carbon filler was synthesized through a simple, eco-friendly one-pot polymerization route, thereby avoiding lignin extraction, purification, and chemical activation steps. Macroporosity was introduced by using poly(methyl methacrylate) microspheres as a hard template, yielding a lightweight carbon material with a foam-like morphology, low density, and high porosity. The carbon filler was incorporated into a silicone rubber matrix at different loadings (5–25 wt.%) to produce flexible composites. The structural, morphological, and textural properties of porous carbon were investigated by SEM, EDX, Raman spectroscopy, nitrogen adsorption, and mercury porosimetry. The electromagnetic properties of composites were measured in the X-band (8.2–12.4 GHz) using a vector network analyzer. The mechanical behavior was evaluated through Young’s modulus. The results show that increasing filler content enhances dielectric losses and attenuation capability. Among all composites, the sample containing 20 wt.% of porous carbon exhibited the best electromagnetic performance, achieving a reflection loss of −42.3 dB at 10.97 GHz with a thickness of 2.43 mm, corresponding to an absorption efficiency of 99.99%. This performance is attributed to a favorable combination of impedance matching and quarter-wavelength cancellation effects. The developed sustainable, lightweight, and flexible composites demonstrate potential as low-cost RAM for aerospace and electromagnetic interference mitigation applications. Full article

With the rapid development of infrared detection methods and military surveillance technologies, flexible and wearable infrared stealth materials (ISM) have attracted increasing attention. Inspired by the layered structure of penguins’ fat–feather–oil, this study prepared a three-layer MXene/waterborne polyurethane (WPU)-foam rubber-phase change microcapsule (PCM)/WPU composite material (M-F-P) via the solution blending and doctor-blading method. The outermost layer of the M-F-P composite is an MXene/WPU conductive film, which features a low infrared emissivity and Joule heating performance to adapt to suddenly cold environments. The porous foam rubber in the middle layer provides excellent thermal insulation performance, which effectively inhibits heat conduction and enhances infrared stealth efficiency. Meanwhile, as a four-directional elastic material, it exhibits deformation recovery capability in both the warp and weft directions as well as the 45° direction. The bottom layer of the PCM/WPU film has a phase change enthalpy of 154.3 J/g and possesses efficient thermal management capability. It achieves dynamic thermal regulation through the cycle of heat absorption at high temperatures and heat release at low temperatures. Full article

One of the key challenges in using CFRP (Carbon Fiber Reinforced Polymer) structures is their susceptibility to low-energy impact damage, often indicated as barely visible impact damage (BVID). Such defects are difficult to detect and can compromise structural integrity. This study investigates the use of immobilized non-Newtonian fluids (NNF) as protective layers for CFRP composites subjected to low-energy impacts. Experimental tests were carried out with an Instron 9440 drop-weight impact tower (impact energy range 5–40 J) and high-speed imaging, comparing NNF coatings with rubber-based, caoutchouc-based, and spray-based protective layers. Non-destructive evaluation using computed tomography confirmed that NNF coatings dissipate impact energy through shear-thickening behavior, reducing delamination while preserving clear visual indicators of the impact site. Furthermore, the study assessed post-impact fatigue bending performance, revealing that the inclusion of NNF—either as an outer layer or as part of a sandwich structure—significantly enhanced the residual fatigue strength of the composites. Moreover, NNFs inherently preserve visible traces of penetration, thereby improving the detectability of impact locations through both unaided visual inspection and advanced imaging modalities such as computed tomography. In addition to external coatings, NNF was applied as a core in sandwich structures, demonstrating improved impact resistance compared to monolithic CFRP laminates and conventional CFRP–foam sandwiches. The protective performance was found to depend on fluid thickness and threshold shear rates required for viscosity transition, indicating that thicker layers do not always provide superior protection. Full article

The steel industry contributes to approximately 7%–9% of global anthropogenic CO_2(g) emissions, with traditional blast furnace–basic oxygen furnace (BF–BOF) routes emitting up to 1.8 t_CO2 per ton of steel. In contrast, Electric Arc Furnace (EAF) steelmaking, especially when integrated with hydrogen direct-reduced iron (DRI), can reduce emissions by over 40%, positioning EAFs as a key enabler of low-carbon metallurgy. However, despite its lower direct emissions, the EAF process still depends on fossil carbon sources for slag foaming and FeO reduction, which are essential for arc stability and energy efficiency. Slag foaming plays a critical role in controlling the thermal efficiency of the EAF by shielding the electric arc, reducing radiative heat losses, and stabilizing the arc’s behavior. This review examines the mechanisms of slag foaming, discussed through empirical models that consider the foaming index (Σ) and slag foaming rate as critical parameters, and highlights the influence of physical properties such as slag viscosity, surface tension, and density on gas bubble retention. Also, the work embraces the potential use of alternative carbon sources including biochar, biomass, and waste-derived materials such as plastics and rubber to replace fossil-based reductants and foaming agents in EAF operations. Finally, it discusses the use of new materials with a biological base, such as nanocellulose, to serve as reactive templates for producing nanohybrid materials, containing both oxides, which can contribute to slag basicity (MgO and/or CaO, for example), together with a reactive carbonaceous phase, derived from the organic fiber’s thermal degradation, which could contribute to slag foaming, and could replace part of the fossil fuel charge to be employed in the EAF process. In this context, the development and characterization of renewable carbonaceous materials capable of simultaneously reducing FeO and promoting slag foaming are essential to achieving net-zero steel production and enhancing the sustainability of EAF-based steelmaking. Full article

Mushroom mycelium-based biomaterials (MMBs) are sustainable materials derived from fungal species and lignocellulosic substrates. In this study, fresh specimens of Panus ciliatus and P. subfasciatus collected from mixed deciduous forests in Chiang Rai Province, Thailand, were identified through a combination of morphological characteristics and phylogenetic analyses based on the ITS region. Panus ciliatus is reported as a new geographical record from Thailand. This is the first comprehensive study on MMB samples developed using mycelia of these species and rubber sawdust for their physical, mechanical, hydrodynamic, and chemical properties. Additional analyses included FTIR spectroscopy, thermogravimetric analysis, flammability testing, and soil burial degradability. Based on the material properties and successfully developed prototypes, the MMBs are potential in packaging, indoor uses, construction, and insulation purposes, as an alternative to conventional synthetic materials. Notably, Ashby chart of mechanical properties showed the MMB could substitute foam. Thermogravimetric analysis of MMB showed thermal stability with weight loss approximately 50–60% at 293–298 °C. Soil burial of MMB for 90 days shows cumulative weight loss exceeding 60% proving biodegradable. Additionally, a new approach for mycelial viability maintenance is described and verified, addressing the problem to maintain vigorous mycelium. Full article

Current ecological and environmental concerns have led to a rapid increase in social interest in research and innovation in the field of sustainable plastics, which directly affects foamed plastic products. In this study, we present our contribution by investigating the effects of egg white protein and corn starch particles on open-cell biofoams produced from natural rubber latex in a two-step process based on an initial aeration that leads to a liquid foam precursor and its dehydration by microwave radiation. By incorporating corn starch and either replacing or maintaining the levels of egg white protein, two independent series of foams were examined. We observed how the reduction in egg white led to bigger and heterogeneous cells, although the density values were practically maintained around 100 kg/m³. In contrast, the formulations with corn starch at a fixed level of egg white protein created foams with homogeneous structures and smaller cells (≤120 µm). In addition, in terms of density, both series present values around 100 kg/m³ for the final solid foams, indicating that the addition of starch does not involve density increments. On the contrary, densities are still low, and the cellular structure homogeneity improves, confirming that starch is a very promising stabilizer bio-particle in the development of biofoams from liquids. Full article

This study investigates the ballistic performance and energy-absorption behavior of advanced multilayer ceramic composite armor systems composed of silicon carbide (SiC) ceramics, composite metal foam (CMF), rolled homogeneous armor (RHA), ultra-high-molecular-weight polyethylene (UHMWPE), aluminum, and rubber interlayers. The objective is to enhance impact resistance and optimize energy dissipation efficiency against armor-piercing (AP) projectiles. Ballistic tests were performed following the NIJ Standard 0101.06 Level IV specifications using .30” caliber AP M2 rounds with an impact velocity of 784–844 m/s. Experimental results revealed that the SiC front layer effectively fragmented the projectile and dispersed its kinetic energy, while the CMF and UHMWPE layers were the primary energy absorbers, dissipating approximately 70% of the total impact energy (≈3660 J). The aluminum and RHA layers provided additional reinforcement, and the rubber interlayer significantly reduced stress-wave propagation and suppressed crack growth in the ceramic. The most efficient configuration 0.5 mm RHA + 7 mm SiC + 7 mm EPDM + 7 mm CMF + 5 mm UHMWPE achieved an areal density absorption of 77.2 J·m²/kg and a unit thickness absorption of 190.6 J/mm. These findings establish a quantitative layer-wise energy dissipation framework, highlighting the synergistic interaction between brittle, porous, and ductile layers. This work provides practical design principles for developing lightweight, high-efficiency composite armor systems applicable to defense, aerospace, and personal protection fields. Moreover, this study not only validates the NIJ Standard 0101.06 ballistic performance experimentally but also establishes a reproducible methodology for quantitative, layer-wise energy analysis of hybrid ceramic-CMF-fiber armor systems, offering a scientific framework for future model calibration and optimization. Full article

Distressed fabric is a popular fashion trend that adds a distinct visual appeal to garments. Distressing involves acid washing with pumice stones containing potassium permanganate. This approach is inappropriate for knitted textiles, which can generate holes and reduce quality. This project seeks to create an Elasto Ball (EB) as an alternative to pumice stones in the acid-washing procedure of knitted materials. The Elasto Ball consists of natural rubber foam filled with silica and a silica–lignin hybrid derived from rice husks. The efficacy of the filler is enhanced during the manufacturing of Elasto Ball by employing the NXT silane coupling agent throughout the silanization process. The silanized elasto ball exhibits thermal stability up to 400 °C and a porosity of up to 5%. In garment washing assessments, the Elasto Ball can diminish the fabric’s color by 40–50% without causing damage. The findings of this study indicate that Elasto Ball can function as an efficient, eco-friendly substitute for washing balls in garment washing procedures. Full article

Rail transport is widely regarded as a sustainable and environmentally friendly option for long-distance freight and passenger movement during its operation phase. However, its construction and maintenance phases often result in substantial environmental impacts, which must be addressed to improve the overall sustainability of railways. This study aims to identify solutions that improve the performance of railway tracks, reduce maintenance requirements, and minimize environmental impact. With this objective, the potential of artificial inclusions and innovative composite materials in enhancing the sustainability of railway tracks is investigated through a comprehensive methodology, combining experimental, analytical and numerical approaches. A novel composite material, comprising soil, scrap tire aggregates and an adhesive, demonstrated strong potential as a sustainable base layer for ballastless railway tracks, exhibiting minimal strain accumulation (0.29–0.98%) under 50,000 load cycles and adequate damping. Incorporation of cellular artificial inclusions in the substructure layers of ballasted tracks reduced cumulative settlement by up to 33% and slowed track geometry deterioration. Use of planar artificial inclusions beneath a pile-supported railway embankment enhanced the load transfer efficiency and curtailed settlement, while also lowering environmental impact by reducing concrete usage. The findings of this study highlight strong potential of these approaches in improving track performance and the overall sustainability of railways. Full article

Waste glass recycling generates waste streams such as fine glass fraction, waste ceramics containing fine glass, and waste polyethylene plastics. All of the aforementioned streams contain contaminants of organic and inorganic origin that are difficult to remove. This research was conducted to determine technological processes aimed at achieving a circular economy (CE) in the recycling of waste glass. Foam glass was made from the fine-grained, multicolored fraction of contaminated glass, an effective method for recycling glass waste at a low cost. A frothing system based on manganese oxide (MnO₂) and silicon carbide (SiC) was proposed, and an optimum weight ratio of MnO₂/SiC equal to 1.0 was determined. The possibility of controlling the process to achieve the desired foam glass densities was demonstrated. Statistical analysis was used to determine the effect of the MnO₂/SiC ratio and MnO₂ content on the density of the resulting foam glass products. Waste ceramics contaminated with different-colored glass were transformed into ceramic–glass granules. The characteristic temperature curve of the technological process was determined. The metal content in water extracts from ceramic–glass granules and pH value indicate their potential use for alkalizing areas degraded by industry and agriculture. Waste polyethylene-based plastics were converted into polyethylene waxes by thermal treatment carried out in two temperature ranges: low temperature (155–175 °C) and high temperature (optimum in 395 °C). The melting temperature range of the obtained waxes (95–105 °C) and their FTIR spectral characteristics indicate the potential application of these materials in the plastics and rubber industries. The integrated management of all material streams generated in the glass recycling process allowed for the development of a CE model for the glass recycling plant. Full article

Lightweightness and durability are key consumer demands for footwear. To address the issues of deformation and poor durability in foamed sole materials, this study integrates natural fibers into the formulation of foamed rubber. The effects of natural fiber incorporation on density, mechanical properties, creep behavior, anti-slip performance, and aging resistance were comprehensively analyzed. Additionally, the study explored the mechanisms underlying the improved performance of the modified rubber materials. The results revealed that natural fiber integration significantly enhanced the structural stability, strength, and aging resistance of natural rubber (NR). Among the fibers compared, collagen fibers (CF) proved to be the most effective modifier for foamed NR. The density, tensile strength, tear strength, and coefficient of friction of CF-modified foamed NR (CF-NR) were found to be 0.72 g/cm³, 10.1 MPa, 48.0 N/mm, and 1.105, respectively, meeting the standard requirements for sole materials. Furthermore, CF-NR demonstrated a recoverable deformation of 4.58% and a negligible irreversible deformation of 0.10%, indicating a successful balance between comfort and durability. This performance enhancement can be attributed to the supportive role of CF in the pore structure, along with its inherent flexibility and recoverability. This work presents a novel approach for the development of high-quality, lightweight footwear in the sole material industry. Full article

Background: The vestibular Romberg test, which assesses the deterioration of balance while standing on rubber foam with closed eyes, is a well-established method in the physical neurological assessment of patients with peripheral vestibulopathy. This study aims to determine whether it can differentiate peripheral vestibulopathy from its main differential diagnosis, namely sensory ataxia, as both conditions typically present with a positive classical Romberg test. Methods: Static balance was assessed in three groups: patients with peripheral vestibulopathy, patients with pure sensory neuropathy, and healthy age-matched controls. Participants stood quietly on a force platform under varying visual and proprioceptive feedback conditions. Conventional and advanced postural sway metrics were investigated to establish a quantitative analogy to both the clinical Romberg and vestibular Romberg tests. Results: Posturographic analysis revealed that, in contrast to healthy controls, patients with vestibular disorders exhibited higher vestibular Romberg quotient values. However, the classical vestibular Romberg quotient did not show diagnostic discrimination between vestibulopathy and sensory neuropathy patients. This lack of discrimination was mainly due to the increased body sway observed in all patient groups under the “eyes open” condition. Nevertheless, a refined vestibular Romberg quotient—comparing standing on foam versus standing on firm support with eyes closed—was able to reliably distinguish vestibulopathy from sensory ataxia. This distinction was evident in both conventional linear sway and spectral postural sway metrics. Conclusions: We conclude that a refined Romberg test, performed solely under conditions of visual deprivation, offers valuable classification potential in differentiating peripheral vestibulopathy not only from healthy controls but also from patients with disequilibrium due to sensory loss. Full article

Foamed asphalt cold recycled mixtures can provide an effective approach for the reutilization of reclaimed asphalt pavement (RAP), but conventional asphalt foaming technology primarily exploits matrix asphalt as the raw material. To address this issue, this study explores rubberized asphalt with cold recycling technology to develop a foamed rubber asphalt cold recycled mixture (FRCM). The semi-circular bending (SCB) test was employed to investigate its cracking resistance. Load–crack mouth opening displacement (CMOD)–time curves under various temperatures were analyzed, and digital image technique was resorted to monitor crack propagation and growth rates. Fracture toughness, fracture energy, and flexibility index were compared with those of traditional foamed matrix asphalt cold recycled mixture (FMCM). The results show that, under the same test temperature, the FRCM exhibits slower crack propagation; larger peak load; and higher fracture toughness, fracture energy, and flexibility index in comparison with the FMCM. These improvements are more pronounced at low temperatures. For both mixtures, fracture toughness and fracture energy are decreased with increasing the temperature, while the flexibility index shows the opposite trend. The rigid zone accounts for a larger portion of fracture energy at low temperatures. The findings provide technical references for improving the cracking resistance of cold recycled asphalt layers using rubberized asphalt. Full article

To address the challenge of balancing static and dynamic strength in the engineering application of foam concrete, this study proposes a strategy to improve the static and dynamic mechanical properties of foam concrete by synergistically adding rubber particles and polypropylene fibers, and systematically analyzes the effects of rubber content, rubber particle size, and fiber content on the material’s compressive strength, flexural strength, and impact toughness. The results show that rubber enhances the dynamic strength of foam concrete through high elastic deformation, with a maximum increase of up to 200%. However, due to the obstruction of hydration reaction, the increase in rubber content reduces the compressive and flexural strength of foam concrete. Meanwhile, the influence of rubber particle size on static strength follows a parabolic trend, with the optimal overall performance achieved at a particle size of 20-mesh, resulting in an approximately 50% enhancement in compressive strength. The addition of fibers to form a three-dimensional mesh structure connecting the cement matrix and rubber particles to inhibit the expansion of cracks can effectively alleviate the deterioration of the static strength of foam concrete caused by rubber particles. The optimal fiber content is 0.2%. In addition, the fiber can also improve the dynamic strength of foam concrete. In addition, the mechanism behind the synergistic improvement of static and dynamic strength by rubber and fiber was summarized. Finally, the optimized proportion and the prediction formulas of static and dynamic strength are established for the above three strength indexes, and the accuracy of the prediction formulas can reach more than 90%. Full article

Disposing of waste tyres in landfills poses significant environmental hazards, making recycling a crucial alternative. Rubberised concrete has been found to exhibit lower density and better thermal insulation performance than conventional concrete. In order to maximise the potential of thermal insulation of rubberised concrete, this study investigates the mechanical and thermal properties of foamed rubberised polypropylene fibre concrete (FRPFC). FRPFC was produced using a mix of crumb rubber (CR) granules, polypropylene fibres, and foam, targeting a density of 800 kg/m³, with CR substituting sand at varying levels. Compressive strength, flexural strength, splitting tensile strength, and thermal conductivity of FRPFC were evaluated. The results demonstrate that increasing CR granule content enhances compressive strength due to reduced porosity from lower foam usage. For instance, compressive strength improved by 55% (2.64 to 4.10 MPa) as CR granule content increased from 0% to 80%. Similarly, flexural strength and splitting tensile strength increased by 55% (1.61 MPa to 2.49 MPa) and 39% (0.41 MPa to 0.57 MPa), respectively, when CR content rose from 0% to 100% at a water-to-cement ratio of 0.50. Furthermore, thermal conductivity decreased by 34% (0.3608 W/mK to 0.2376 W/mK) when sand was fully replaced with CR granules, showcasing improved thermal insulation. Statistical analysis using ANOVA confirmed that the crumb rubber content significantly influences the mechanical and thermal properties of FRPFC, with higher CR content (80% and 100%) leading to superior performance. These findings highlight FRPFC’s potential as an environmentally sustainable and thermally efficient construction material, contributing to enhanced mechanical properties compared to conventional foamed polypropylene fibre concrete. Full article