Recently, thin-film light-emitting devices have attracted considerable attention due to their potential application in displays and lighting [...].
Recently, thin-film light-emitting devices have attracted considerable attention due to their potential application in displays and lighting [...].
The use of end-of-life tyre (ELT) rubber as a partial aggregate replacement in concrete represents a promising route for waste valorisation; however, its durability-related behaviour and long-term performance remain insufficiently characterised, particularly under combined environmental exposures. This study addresses these limitations by combining a targeted literature review encompassing more than 4500 data points from over 150 published studies with a laboratory-based experimental assessment of rubberised concretes aimed at clarifying key knowledge gaps. The experimental programme investigates concretes incorporating 5-50% ELT rubber (0/4 mm) as a selective replacement of a specific sand fraction, rather than of the total fine aggregate content, with particular emphasis on performance under coupled freeze-thaw cycling and sulphate attack. A reference mix (>50 MPa at 28 days) and seven rubberised concretes were characterised in terms of mechanical behaviour and selected durability-related indicators. Specimens were subsequently exposed for 270 days to freeze-thaw cycles (-20/+20 °C) in a 10% MgSO4 solution, and surface damage and compressive strength loss were quantified. Increasing rubber content resulted in the expected reductions in mechanical performance, accompanied by lower electrical resistivity and increased porosity and carbonation depth. However, the selective replacement of a single sand fraction led to more gradual deterioration than typically reported for global sand substitution. Under combined freeze-thaw and sulphate exposure, concretes with low rubber contents (5-15%) exhibited no observable surface damage and retained most of their mechanical capacity, with compressive strength losses below 8%, whereas mixtures with ≥30% replacement showed pronounced surface degradation and strength losses exceeding 50%.
Development of biodegradable polymer composites provides a sustainable alternative to conventional plastics. This study systematically investigates the effect of Eucomis autumnalis (EA) cellulose on the morphological, structural, and thermal behavior of polybutylene succinate (PBS) and polycaprolactone (PCL) blends. EA cellulose was extracted via delignification and hemicellulose removal, yielding 38% cellulose from the leaf biomass. A series of PBS/PCL/EA cellulose composites were prepared using a solution-casting method. Fourier-transform infrared spectroscopy (FTIR) confirmed retention of characteristic functional groups, with spectra dominated by PCL features, indicating the absence of new chemical bond formation between EA cellulose and the polymer matrix. X-ray powder diffraction (XRPD) revealed that EA cellulose acted as a nucleating agent, enhancing the crystallinity, especially in PCL, while slightly affecting PBS crystallization. A scanning electron microscopy (SEM) analysis demonstrated preferential localization of EA cellulose within the PBS phase, contributing to improved phase dispersion and interfacial interaction at the morphological level. Differential scanning calorimetry (DSC) showed enhanced crystallization behavior of PCL at higher EA cellulose loading (5 wt.%), with minimal influence on PBS thermal transitions. A thermogravimetric analysis (TGA) indicated that the thermal stability depends on the polymer composition and cellulose content, with higher PCL fractions contributing to an improved stability. This study provides insight into the structure-property relationships governing PBS/PCL/EA cellulose systems and highlights the potential of EA cellulose as a bio-based additive for tailoring morphological and thermal characteristics of biodegradable polymer blends. A mechanical performance evaluation is recommended for future studies to correlate structural modifications with macroscopic properties.
In the current numerical simulation study of high-strength steel welding, ignoring the phase transformation plasticity effect in the coupling analysis led to a significant deviation between the simulated value of residual stress and the experimentally measured value. To investigate the influence mechanism of the Welding Residual Stresses (WRSs) of 30MnCrNiMo armor steel, the transformation plasticity (TP) coefficient (7.81 × 10-5 MPa-1) was measured via a Gleeble 3500, and a Finite Element Model (FEM) of thermal-metallurgical-mechanical coupling considering yield strength, volumetric strain and TP behavior in Solid-State Phase Transformation (SSPT) was developed. The results show that the volume expansion during the SSPT is the main factor for the shift in WRS from tensile to compressive. In contrast, the TP effect reduces the peak longitudinal tensile stress in the Heat-Affected Zone (HAZ) by 51 MPa. It also ultimately neutralizes the compressive component in this region. When the martensite fraction ranges from 0.12 to 0.45, transformation plastic strain becomes the dominant factor, leading to a characteristic evolution of longitudinal stress that initially decreases and subsequently increases. The FEM incorporating the TP effect successfully captures the dual reversals of residual stress in the HAZ. The average relative error between the simulated longitudinal stress and the experimental data obtained via X-ray diffraction (cosα method) is 8.8%. The TP coefficient database and the developed multi-field coupling model markedly enhance the predictive accuracy for WRS in 30MnCrNiMo steel, offering a robust theoretical foundation for the design of stress corrosion resistance and the service life assessment of welded joints in armored vehicles.
The use of a multi-component binder (MCB), consisting of Ordinary Portland Cement (OPC) combined with one or more supplementary cementitious materials (SCMs), has gained prominence for enhancing sustainability and improving the performance of cementitious systems. This study provides an integrated approach to optimize both binder composition and aggregate gradation through advanced mixture design and particle packing techniques. The MCB system consists of OPC partially replaced with SCMs such as fly ash (FA), Ground Granulated Blast Furnace Slag (GGBFS), metakaolin (MK), and silica fume (SF), with particle sizes ranging from micron to sub-micron scale. The D-optimal mixture design (DOD) method is used to determine the optimal material proportions by evaluating the relation between binder composition and wet packing density measured through the wet packing method (WPM). To further enhance packing efficiency, the Modified Toufar Model (MTM) is employed to optimize fine aggregate gradation. The maximum packing density is considered the primary criterion for identifying the optimal mix design, as it reflects the minimum void ratio and the most efficient particle size distribution. The optimized mortar mixes are evaluated for mechanical strength, pozzolanic reactivity, capillary water sorptivity, and drying shrinkage. Results indicate that the optimized MCB and optimized fine aggregate gradation improve the packing density and pozzolanic activity, significantly enhancing strength and durability performance. The incorporation of SCMs offers an effective strategy to improve performance while mitigating carbon emissions. Compared with C100, CFGMS-based systems achieved energy reductions of 35-40% and CO2 emission reductions of 34-48%.
The Special Issue "Advances in Multifunctional Materials Obtained at High Temperature and Pressure" comprises a series of articles focused on studying materials obtained from powders [...].
The use of aeolian sand as a fine aggregate in concrete production provides a sustainable pathway to valorize abundant aeolian resources while alleviating the global shortage of natural construction aggregates. However, the high ultrafine particle content of aeolian sand results in the formation of highly porous interfacial transition zones (ITZ) between sand particles and cement paste, which is the primary cause of the inherent brittleness and inferior mechanical performance of aeolian sand concrete. To overcome this critical limitation, an alkali-activated surface layer (ASL) was constructed on aeolian sand via 4 mol/L KOH activation. This process induced the surface micro-dissolution of minerals to create high-density active ion sites (specifically Ca2+, K+, Na+, and Fe3+). These sites facilitated the precise anchoring of carbon nanotubes (CNTs) through the chemical coordination of single-stranded deoxyribonucleic acid (ssDNA). The influence of the ASL and the ssDNA/CNTs nanocomposite on the ITZ was elucidated through macro-mechanical testing and multi-scale microstructural characterization. Experimental results demonstrated that compressive strength, flexural strength, and compressive energy dissipation increased by 48%, 67%, and 42%, respectively. Microstructurally, the modification promoted a pore refinement mechanism, reducing the proportion of harmful (pores > 0.1 μm) from 51% to 20% and narrowing the ITZ width from 20-40 μm to 10-15 μm (a 67% reduction). The observed performance enhancement is attributed to the synergistic effect of the ASL and ssDNA/CNTs, which transforms the inherently weak ITZ into a chemically reinforced interfacial phase via molecular-scale coordination bonding and optimized stacking of cement hydration products.
Gas Metal Arc Welding (GMAW) is widely adopted in automated manufacturing industries where the accurate prediction of thermal fields and welding-induced distortions is essential to ensure joint integrity of the parts; however, finite element modeling, as the most reliable non-destructive predictive approach, remains time-consuming and highly user-specialized. This work presents an automated and low computational cost thermo-mechanical finite element methodology implemented in Ansys Parametric Design Language (APDL) for the parametric analysis of GMAW T-joints, integrating automated geometry generation, meshing, heat source implementation, and thermo-mechanical modeling for different beam and weld seam dimensions under continuous or intermittent single-pass configurations. A volume element selection strategy is introduced to limit heat input calculations to the active weld pool region, achieving up to a 50% computational time reduction while maintaining high predictive accuracy, in contrast with conventional and partial selection methods. Overall script performance was validated through temperature and displacement comparisons between the numerical and experimental results of two T-joint configurations using SM490A structural steel specimens. The results demonstrate that the developed macro provides a useful tool for automated thermo-mechanical welding analysis, significantly reducing model preparation effort while enabling the evaluation of parametric T-joint geometries and welding conditions with a low computational cost focus.
SCM-10 is an SFE-type borosilicate zeolite featuring one-dimensional 12-ring channels and holds promise for catalytic and separation applications, yet its crystallization and morphology control remain insufficiently understood. Herein, we investigate the crystallization of SCM-10 and elucidate the effects of synthesis parameters, including SiO2/B2O3, OSDA/SiO2, and H2O/SiO2 molar ratios, crystallization temperature, and heteroatom substitution, on crystal morphology. SCM-10 crystallizes via an induction period (30 h) followed by rapid crystal growth (12 h), yielding uniform needle-like crystals with dimensions of 0.05 × 1 μm (diameter × length; aspect ratio = 20). Increasing the SiO2/B2O3 ratio induces a morphology transition from needles to plates, whereas variations in the OSDA/SiO2 and H2O/SiO2 ratios largely preserve the needle-like morphology. Elevating the crystallization temperature transforms needles into nanowires, with the aspect ratio rising to 83 (0.03 × 2.5 μm). Heteroatom substitution further induces distinct morphology modulation: Al yields nanoparticles (100 nm), V shortens crystal lengths to 500 nm (50 × 500 nm; aspect ratio = 10), Fe produces nanowires (0.02 × 1.3 μm; aspect ratio = 65), and Ge forms peanut-like needle aggregates (0.05 × 10 μm; aspect ratio = 200). This work establishes morphology-regulation rules for SCM-10, enabling the rational design of tailored morphologies for applications.
In this study, the corrosion behavior of CuXCoCrMoNi (x = 0.3, 0.6, 0.9) high-entropy alloys (HEAs) in 3.5% NaCl solution is systematically investigated. The alloy samples show a strong link between copper content and corrosion resistance. It is noteworthy that an increase in copper content promotes element segregation, resulting in an increase in corrosion current density from 2.138 × 10-7 μA/cm2 to 1.8989 × 10-6 μA/cm2 and a decrease in charge transfer resistance from 182.6 Ω·cm2 to 42.34 Ω·cm2. In addition, electrochemical experiments demonstrate that lowering the copper content in the alloys reduces the spread and depth of corrosion. All alloys exhibit n-type semiconductor behavior, with donor density increasing from 4.792 × 1023 cm-3 to 5.581 × 1023 cm-3 with increasing copper content. Notably, the passive film is characterized by the presence of Cr2O3 and Cu2O as its main constituents. As the copper content in the HEA increases, higher levels of copper oxides in the passive film inhibit the formation of chromium oxides. This degrades the passive film quality, thereby diminishing the overall corrosion resistance.
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