Abstract: Construction-waste recycling offers a viable pathway toward sustainable concrete production. In this study, waste bricks were processed into recycled brick powder (RBP), recycled brick sand (RBS), and recycled brick coarse aggregate (RBCA) for use in single- and multi-blend 3D-printable recycled concrete, aiming to reduce natural aggregate and cement consumption. The effects of RBP, RBS, and RBCA on rheology, printability, and mechanical performance were systematically evaluated, and response surface methodology (RSM) was used to model and optimise compressive strength. Results showed that RBP had the strongest influence on rheology, increasing static and dynamic yield stresses by 50.99% and 101.61% at 30% replacement. Yield stress first increased and then decreased with increasing RBCA, reaching a peak at 20%. Rheological behaviour governed printability: higher static yield stress improved build height, whereas higher dynamic yield stress reduced extrusion width. Compressive strength showed a non-linear response, increasing by 1.26% at 10% RBP but decreasing by 24.87% and 15.33% under full RBS and RBCA replacement. RSM identified an optimal blend of 12.4% RBP, 25.1% RBS, and 51.8% RBCA, balancing sustainability and mechanical performance for 3D concrete printing. Read More

Abstract: To address the issues of low strength and poor construction efficiency of traditional insulation materials, this study prepared insulation cement-based materials using glass microspheres as lightweight aggregates through 3D printing technology. Through orthogonal experimental design, the influence of glass microsphere dosage (70% to 110%) on the working performance, mechanical properties and insulation performance of the materials was systematically investigated. The results show that as the dosage of glass microspheres increases, the fluidity of the slurry gradually decreases, and the 28-day compressive strength drops from 5.85 MPa to 0.74 MPa, but the thermal conductivity significantly decreases from 0.1445 w/(m·k) to 0.0632 w/(m·k). When the dosage of glass microspheres is 100%, the material has both good mechanical properties (1.48 MPa) and insulation performance (0.0718 w/(m·k)), meeting the requirements of Type II products in the building insulation mortar standard GB/T 20473-2021. This study provides theoretical basis and technical support for the engineering application of 3D printed insulation cement-based materials. Read More

Abstract: In recent years, the application of metal halide perovskites in the field of photocatalysis has emerged as a rapidly developing research area. However, the toxicity and stability issues of traditional lead (Pb)-containing perovskites limit their large-scale application. Therefore, the development of efficient and stable lead-free perovskite materials is one of the key current research directions. Cs3Bi2X9 (X = I, Br, Cl), as a lead-free metal halide perovskite, offers the primary advantages of being environmentally friendly and having potentially higher stability. This article provides an overview of the application of this material system in replacing lead-based perovskites to achieve environmentally friendly photocatalysis, as well as its synthesis methods. It aims to serve as a reference for the development of efficient and stable lead-free perovskite photocatalysts. Read More

Abstract: The Bouligand structure, also known as a helicoidal fibrous structure, appears extensively in natural biological tissues with excellent mechanical properties, such as the dactyl clubs of mantis shrimp, the exoskeletons of lobsters, and the scales of fish; because this highly unique layer-by-layer architecture is formed by stacking single-direction fibrous sheets in a spiral manner at specific angles, it can equip biological tissues with exceptional fracture resistance, anti-impact capabilities, and damage tolerance; if the relationship between this structure and its performance can be thoroughly understood, and this mechanism can then be applied to artificially manufactured systems, it would be of immense value for the development of new, high-performance composite materials; this article primarily lists classic examples of Bouligand structures in natural environments, carefully analyzes the internal principles that enable it to increase material toughness, which include crack deflection, crack twisting, and the bridging effect between fibers, and summarizes the main methods used in recent years to artificially biomimic and manufacture this structural material, such as 3D printing, material self-assembly, and assembly through shear forces, while also forecasting the roles this material could play in fields like aerospace, national defense, and medical health in the future. Read More

Abstract: This chapter investigates a CTNT (C/TiO₂/Ti) fiber platform modified with an iron-based active phase for non-enzymatic glucose sensing. Iron catalytic sites were introduced onto the CTNT electrode without binders to improve interfacial reaction efficiency and signal stability during glucose electro-oxidation. A conductive porous core-shell CTNT fiber electrode was first prepared by anodization and gas-phase carbonization, followed by potentiostatic electrodeposition using FeCl₃ to obtain Fe@CTNT. SEM/EDS was used to analyze the loading state and distribution of the iron species, and the cyclic voltammetric response, working potential, amperometric sensing performance, anti-interference behavior, cycling stability, and preparation reproducibility were systematically evaluated in 0.1 M NaOH under the same conditions as for Ni@CTNT. These results provide an experimental basis for applying iron-based systems in fiber-shaped flexible electrodes. Read More

Abstract: This study systematically investigates the laser wire filling welding (LWFW) process of 6061-T6 aluminum alloy lap joints using ER5356 filler wire. The influence of critical process parameters, including laser power, welding speed, and wire feed speed, on weld formation, microstructural evolution, and mechanical properties was evaluated. The results demonstrate that line energy input, determined by laser power and welding speed, is the primary factor governing penetration depth and macroscopic quality. An increase in laser power significantly enhances penetration by stabilizing the keyhole effect, while higher welding speeds refine the Heat-Affected Zone (HAZ) grains by reducing thermal residence time. Microstructural analysis revealed distinct zoning, with fine equiaxed grains in the weld metal (WM) and columnar crystals near the fusion line. The tensile strength of the joints is determined by the synergy between the effective bonding area (penetration depth) and fine-grain strengthening. Under the optimized conditions of 2.8 kW laser power, 25 mm/s welding speed, and 4.0 m/min wire feed speed, high-quality joints with a tensile strength of 195 MPa (approximately 63% of the base metal strength) were obtained. This research provides a theoretical and technical basis for the application of LWFW in automotive aluminum component manufacturing. Read More

Abstract: This study focuses on Tibetan lamb meat from the Qinghai Tibet Plateau, local sheep meat from Shandong, and goat meat. Using a combination of headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) and headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), the differences in volatile flavor compound composition and overall flavor profile of the three types of lamb meat were systematically analyzed and compared. Qualitative analysis of flavor compounds was conducted using GC-MS and principal component analysis (PCA) was used to identify the dominant factors affecting flavor differences in different types of lamb meat; Using GC-IMS to obtain fingerprint and two-dimensional differential spectra of volatile substances, achieving intuitive and sensitive differentiation of three types of lamb flavor characteristics. The results showed that GC-MS identified a total of 19 volatile substances, including 8 aldehydes, 5 alcohols, 4 esters, and 2 other compounds. Among them, 16 were detected in Tibetan sheep, 11 in local sheep and 15 in goats. The content of aldehydes such as hexanal and heptanal in Tibetan sheep was significantly higher than that in the other two types of lamb meat; GC-IMS detected a total of 26 volatile compounds, including 8 esters, 6 aldehydes, 9 alcohols and 2 others. Butyl formate and n-hexanol are characteristic flavor compounds of Tibetan sheep, while 2-furanyl methanol acetate is a unique substance of goats. Principal component analysis shows that aldehydes are the core contributing category to the flavor differences among the three types of lamb meat; The HS-GC-IMS fingerprint spectrum intuitively presents the differences in the content and types of three volatile substances in lamb meat.trans-2-Decenal, 1-octen-3-ol, hexanal, 2-heptenal, and nonanal were identified as key volatile compounds through the combination of variable importance in projection (VIP) from PLS-DA and ROAV. The aroma profile radar … Read More

Abstract: Cross-linking reaction flow forming is an advanced technology for preparing hollow fiber hydrogels, featuring simple process, continuous meter-level preparation and 3D structure construction. However, hydrogel sensors made by this method have poor tunability in mechanical and electrical properties, limiting their application. To solve this, this study focuses on the design, preparation, performance testing of heteromorphic lumen hydrogel sensors and their application in flexible sensors. Firstly, an experimental platform for precise extrusion control was built using a coaxial nozzle and microinjection pump system. By adjusting the flow rate of inner-phase calcium chloride (with outer-phase sodium alginate), variable-diameter heteromorphic lumen hydrogels were precisely prepared. A theoretical model based on flow rate regulation was proposed to characterize lumen morphology changes, providing theoretical support for structural optimization. Subsequently, the effects of sodium alginate (3%–5%) and lithium chloride (3%–5%) concentrations on hydrogel properties were explored. Results show that higher sodium alginate concentration improves tensile strength, elongation at break and fatigue resistance, while electrical properties first rise then fall. Higher lithium chloride concentration reduces mechanical properties but enhances electrical conductivity (with significant strain-dependent changes). The optimal formulation (3.75% sodium alginate, 5% lithium chloride) achieves 65 kPa maximum stress and 33.86 S/m maximum conductivity. In summary, this study realized precise regulation and performance optimization of hydrogel sensors via heteromorphic lumen design. Flow rate adjustment and concentration optimization are crucial for improving their mechanical, electrical and sensing properties, providing theoretical and practical support for their application in high-precision biological signal monitoring and flexible electronics. Read More

Abstract: Building energy consumption accounts for approximately 35%–40% of global total energy use, making the improvement of envelope thermal performance a key strategy for building energy efficiency. Thermal insulation mortar has been widely used in building energy renovation due to its convenient construction, relatively low cost, and good compatibility with substrate walls. Although traditional lightweight aggregate thermal insulation mortars (e.g., expanded perlite, glazed hollow beads, EPS particles) can reduce thermal conductivity, they suffer from high water absorption, low compressive strength, drying shrinkage cracking, and insufficient long-term durability, which limit their application in high-performance energy-saving systems. In recent years, research has increasingly shifted toward aerogel-based thermal insulation cementitious composites. Aerogel, featuring a nanoporous structure, ultra-low density, and extremely low thermal conductivity, significantly reduces the thermal conductivity of mortar, enabling lightweight and highly efficient thermal insulation. However, the incorporation of aerogel also leads to a marked decline in mechanical properties, primarily due to the low strength of aerogel itself and the weak interfacial bonding between its hydrophobic surface and the cement paste, which tends to form interfacial transition zone defects and pore-rich regions. To address these challenges, researchers have focused on several aspects, including mix proportion design to balance thermal and mechanical performance by adjusting aerogel content, water-to-binder ratio, and admixtures; interface modification using silane coupling agents, dispersion aids, and low-shear mixing to improve compatibility and dispersion uniformity between aerogel and the cement matrix; fiber reinforcement through the introduction of polypropylene (PP), PVA, basalt and other fibers to bridge cracks, enhance toughness, and compensate for strength loss and cracking tendency; and … Read More

Abstract: The growing demand for lightweight yet crashworthy automotive structures has promoted the use of 1.5 GPa grade martensitic steels (MS1500 1). However, laser welding of such ultra high strength materials is challenged by heterogeneous microstructures and severe hydrogen induced delayed cracking (HIDC) risks. This study systematically investigates the laser welding behavior and hydrogen embrittlement susceptibility of MS1500 1, focusing on three aspects: (1) the effect of surface oil contamination (oil free, 1.5 g/m² as received, and 3.0 g/m² excessive lubricant) on microstructural evolution and mechanical performance of laser lap welded (L bend) and butt welded joints; (2) the hydrogen permeation and diffusion behavior in the base metal using electrochemical permeation tests; and (3) the correlation between microstructural features of distinct heat affected subzones, local hardness distribution, and overall joint integrity. Comprehensive microstructural characterization (optical microscopy, scanning electron microscopy, X ray diffraction), mechanical evaluation, and hydrogen permeation measurements reveal that surface oil significantly alters the weld thermal cycle and hydrogen uptake, leading to pronounced softening and increased HIDC susceptibility. The results establish a fundamental understanding of hydrogen trapping characteristics and mechanical reliability of laser welded MS1500 1 joints, providing a scientific basis for mitigating delayed cracking and developing robust welding protocols for ultra high strength steel components in automotive manufacturing. Read More