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A20X is an advanced and high-strength additive manufacturing aluminum alloy with promising applications in several fields, including aerospace and aeronautics. However, its assembling through fusion welding technologies poses challenges due to the detrimental effects of melting and solidification. Friction stir welding offers a promising solution for joining A20X, producing components with superior mechanical properties while preserving the engineered microstructures. This study investigates the influence of friction stir welding on the quality of butt joints made of 4 mm thick additively manufactured A20X plates produced by laser powder bed fusion. Different rotational (900 and 1500 rpm) and welding speeds (100 and 500 mm/min) were tested to evaluate the influence of the joining process on weld quality (mechanical strength, microstructures, welding defects, and surface roughness). Friction stir welding maintains a very fine microstructure in the welds, with only a slight reduction of the mechanical strength compared to the base material (335 MPa vs. 385 MPa on average). The hardness of the welded joints increases, attributed to local aging caused by the heat input during the joining process. Lower tool rotation and welding speed result in tunnel defects, notably reducing joint strength. 3D X-ray computed tomography reveals that the metal stirring occurring during the joining process notably reduces the intrinsic porosity of A20X. It also breaks up Ti borides and promotes the growth of Al-Cu precipitates within the stir zone. The fractographic analysis highlights the ductile behavior of A20X after welding, emphasizing the critical role of welding parameters in joint integrity. [ABSTRACT FROM AUTHOR]

The dye removal effect of the anisotropic polysaccharide-ZIF-8 aerogel via adsorption and catalysis was observed, highlighting the great potential of the hybrid aerogel as a highly effective, sustainable, and low energy-consuming environmental remediation material. The hybrid aerogel with remarkable mechanical strength has excellent prospects for regeneration to extend its lifespan. [Display omitted] Assembling microscopic metal–organic frameworks into macroscopic polymeric scaffolds to develop highly renewable materials has been a promising yet challenging area of research. Herein, chitosan (CS) blended with nano-cellulose (NC) was unidirectionally transformed into an aerogel with oriented macropores and then biomineralized with zeolite imidazolate frameworks-8 (ZIF-8) to form a hierarchical structured chitosan-nanocellulose/zeolite imidazolate frameworks-8 (CS-NC-ZIF-8) hybrid aerogel. Incorporating ZIF-8 significantly increases the versatility and mechanical strength with a Young's modulus of 14.18 MPa of the CS-NC aerogel. The incorporation of ZIF-8 into the aerogel not only enhances its adsorption capacity for methylene blue, rhodamine B, acid fuchsin, and methyl orange, but also facilitates the generation of electrons from water that can be transferred to degrade > 90 % of malachite green within 90 min in each catalytic cycle, and this capability was maintained for at least 10 consecutive cycles. Remarkably, the hybrid aerogel was highly renewable after the adsorption of cationic dyes and catalytic removal of malachite green. With its facile production process, high removal efficiency, affordable and green nature, and excellent regeneration feasibility, the CS-NC-ZIF-8 aerogel stands as a promising solution for addressing challenges associated with dye-contaminated water treatment. [ABSTRACT FROM AUTHOR]

Swelling-shrinkage deformation of expansive soils is the primary governing factor for development of the crack network, which is intimately associated with the bearing capacity and the structural integrity of the soil body. To suppress the swelling-shrinkage characteristic, sintered red mud was utilized as a curing agent to stabilized expansive soil, and the physical property testing phase consisted of compaction tests, Atterberg limit tests and pH tests to derive patterns on the physical and mechanical properties of the expansive soil influenced by the incorporation of red mud. The principal engineering property tests include unconfined compressive tests, one-dimensional swell tests, desiccation-induced crack study and micro-structure analysis by scanning microscopy techniques. The test findings demonstrate that even red mud would somewhat weaken the strength, but restrict the plasticity and successfully prevent swelling-shrinkage deformation of expansive soils. Such an effect is positively correlated with the red mud content. When the content reaches 20%, the crack ratio reduction exceeds 40%, the swelling deformation are reduced by about 20%, and the unconfined compressive strength higher than 500 kPa with dry density of 1.6 g/cm3. The stabilization of expansive soils with red mud effectively increases the structural integrity of the soil layers and the safety of constructions to offer guidance for environmentally friendly construction in expansive soil areas. [ABSTRACT FROM AUTHOR]

Silk fibroin (SF) is an ideal material for microneedle (MN) preparation. However, long extraction and short storage durations limit its application. Furthermore, MNs prepared from SF alone are easy to break during skin insertion. In this study, a regenerated SF solution was autoclaved and freeze-dried to produce a stable and water-soluble SF sponge. The freeze-dried SF (FD-SF) solution was ultrasonically treated before being used in the fabrication of MNs. The ultrasonically modified SFMNs (US-SFMNs) were evaluated in comparison to FD-SFMNs made from FD-SF and conventional SFMNs made from regenerated SF. The results indicated that the FD-SF could be completely dissolved in water and remained stable even after 8 months of storage. FTIR and XRD analyses showed that SF in US-SFMNs had increased β-sheet content and crystallization compared to FD-SFMNs, by 7.3% and 8.1%, respectively. The US-SFMNs had higher mechanical strength than conventional SFMNs and FD-SFMNs, with a fracture force of 1.55 N per needle and a rat skin insertion depth of 370 μm. The US-SFMNs also demonstrated enhanced transdermal drug delivery and enzymatic degradation in vitro. In conclusion, the autoclaving and freeze drying of SF, as well as ultrasonication-induced MN preparation, provide promising SF-based microneedles for transdermal drug delivery. [ABSTRACT FROM AUTHOR]

Bioceramics composed of calcium and magnesium silicates have garnered increasing attention for the development of porous scaffolds in bone tissue engineering (BTE). This heightened interest is primarily attributed to their remarkable bioactivity and their capacity to form strong bonds with hard tissue. Fabricating nanocomposite scaffolds is a recognized approach for improving the characteristics of scaffolds used in BTE. This research investigates the mechanical and biological properties, antibacterial activity, and drug-release characteristics of scaffolds composed of akermanite (AKT), monticellite (MON), and monticellite-akermanite (MON-AKT). These scaffolds were fabricated utilizing the space holder process. Additionally, the in vitro drug release profile and antimicrobial activity of Azithromycin (AZT)-loaded MON-AKT composite scaffolds were investigated. The findings showed that the Mon-15 wt% AKT nanocomposite scaffold had the highest density, the smallest grain and micropore sizes, and the lowest porosity. In contrast, integrating AKT into MON-based composite scaffolds resulted in materials characterized by high mechanical strength and stability within physiological environments. The MON-AKT nanocomposite scaffolds exhibited cytocompatibility and demonstrated a high level of alkaline phosphatase (ALP) activity in osteogenic studies. Furthermore, antimicrobial activity assessments revealed that the AZT-encapsulated MON-AKT composite scaffolds effectively inhibited the growth of both S. aureus and E. coli bacteria. The outcomes showed that the antibacterial efficacy of the scaffold depends on both the amount of AZT and the type of bacteria. Overall, MON-AKT/3AZT scaffolds exhibited significantly superior bacterial inhibition compared to other scaffolds, making it a promising option for treating bone tissue defects. [ABSTRACT FROM AUTHOR]

[Display omitted] Low mechanical strength is still the key question for collagen hydrogel consisting of nanofibrils as hard tissue repair scaffolds with no loss of biological function. In this work, novel collagen nanofibrous hydrogels with high mechanical strength were fabricated based on the pre-protection of trisodium citrate masked Zr(SO 4) 2 solution for collagen self-assembling nanofibrils and then further coordination with Zr(SO 4) 2 solution. The mature collagen nanofibrils with d -period were observed in Zr(IV) mediated collagen hydrogels by AFM when the Zr(IV) concentration was ≥ 10 mmol/L, and the distribution of zirconium element was uniform. Due to the coordination of Zr(IV) with ─COOH, ─NH 2 and ─OH within collagen and the tighter entanglement of collagen nanofibrils, the elastic modulus and compressive strength of Zr(IV) mediated collagen nanofibrous hydrogel were 208.3 and 1103.0 kPa, which were approximate 77 and 12 times larger than those of pure collagen hydrogel, respectively. Moreover, the environmental stability such as thermostability, swelling ability and biodegradability got outstanding improvements and could be regulated by Zr(IV) concentration. Most importantly, the resultant hydrogel showed excellent biocompatibility and even accelerated cell proliferation. [ABSTRACT FROM AUTHOR]

The paper presents the investigation on the influence of humidity, heat treatment temperature, the grain size distribution of periclase, aging time prior to heat treatment, and the amount of carbon in the charge on the strength properties of periclase-carbon samples. It is established that the moistening prior to heat treatment and aging duration have no influence on the mechanical strength of the materials. The mechanical strength of the samples increases with the increase in the concentration of finer particles of periclase in the charge. Given that the variation in carbon content (ranging from 3 to 11%) has no significant impact on the mechanical strength of the samples, it is recommended that the carbon content (in the form of graphite) in the charge mixture be determined on a case-by-case basis, in line with the intended use of the periclase-carbon products. In the investigated temperature range (125 – 250°C), the highest mechanical strength of the samples was observed at a heat treatment temperature of 200°C. [ABSTRACT FROM AUTHOR]

The effect of silica (SiO 2) addition (0 wt%-20 wt%) on the microstructural and mechanical properties, as well as the in vitro response of calcium phosphate scaffolds for potential application in bone tissue engineering (BTE) was investigated in this research. Scaffolds characterized by high porosity (77%–88 %) and interconnected spherical pores with a broad range of pore sizes (5–600 μm) were fabricated using in-situ foaming method. Incorporated silica affected the phase transformation of hydroxyapatite (HA) to β-tricalcium phosphate (β-TCP) and led to the development of new crystalline silica-rich phases like silicocarnotite and wollastonite. The reinforcement of silica became apparent during the tests of mechanical properties. Scaffolds with 5 wt% of SiO 2 exhibited compressive strength (1.13 MPa) higher than pure HA scaffolds (0.93 MPa). Bone bonding potential of the materials was tested in simulated body fluid (SBF), demonstrating this potential in silica-doped samples. Additionally, degradation experiments showed gradual material degradation, making it suitable for BTE applications. Furthermore, cell culture studies using human mesenchymal stromal cells (MSC) confirmed the scaffold's non-toxicity and provided insights into how the silica content influences cell viability, morphology, and osteogenic potential. The findings of this study offer valuable insights into the design and development of advanced scaffolds with tailored properties for effective BTE applications. [Display omitted] • In vitro evaluation of bioactive potential of multiphase porous ceramic materials for non-loadbearing bone regeneration. • In-situ foaming technique was used to produce porous bioceramic. • Si-containing phases undergo selective degradation under conditions that simulate osteoclastic activity. • Si-containing phases release Si into test media during degradation tests – possible osteoblastogenetic response in vivo. [ABSTRACT FROM AUTHOR]

At elevated operating temperatures, a large temperature gradient can cause irreparable damage to the solid oxide fuel cells (SOFCs) stack, eventually interrupting the durability of the stack. Metal substrate support could be used to overcome this challenge. However, the application of metal substrate support poses various challenges such as different thermal expansion coefficients, pore diameters, and complex fabrication techniques. Therefore, a first-ever novel and mechanically strong ferritic stainless-steel metal mesh-supported SOFC design is developed to mitigate these challenges. The metal mesh of 200 μm thickness is laminated with tape-casted green films of anode-support, anode functional layer (AFL), and electrolyte films of SOFC. The iso-static pressure of 300 MPa exhibits a firm attachment of the green films of SOFC with the metal mesh. Subsequently, the metal mesh-supported planar SOFC exhibits 3.3 times higher flexural strength compared to the conventional commercial anode-supported planar SOFC. The nano-CuO is added to constituent layers as a sintering aid to attain the maximum density at a lower sintering temperature of 1100 °C. The result shows that the practical application of the metal mesh-supported cell technology has a great potential to overwhelm the mechanical durability of SOFCs. [ABSTRACT FROM AUTHOR]

Cracks induced by internal stresses compromise the structural integrity of ceramic laminates. Such stresses can be classified into thermal stress derived from thermal expansion mismatch and shrinkage stress derived from shrinkage mismatch. Analytical models have been proposed for the former, whereas only numerical predictions have been explored for the latter. In this study, an equation is constructed to predict the shrinkage stress by modifying an elastic solution proposed in previous studies. We fabricated laminates with three‐layer sandwiched structures using only alumina specimens with high and low densities to control the shrinkage and avoid thermal mismatch. Surface cracks were initiated when the shrinkage stress exceeded the flexural strength of the surface layer. Although the original strength of the surface layer was 308.8 MPa, the laminates' flexural strength was lower than that because of shrinkage constraint. Our results demonstrate that the shrinkage stress was successfully estimated analytically using a few material properties measured in an ordinary environment. This study will ensure the structural integrity of ceramic laminates in laminate designs. [ABSTRACT FROM AUTHOR]

In recent years, various aspects of research related to pervious concrete (PC) have progressed rapidly, and it is necessary to summarise and generalise the latest research results. This paper reviews and compares the raw materials of pervious concrete, examining elements such as porosity, permeability, mechanical properties, and durability. According to comparisons, we put forward an ideal aggregate model with Uneven Surface, which may reinforce the mechanical properties. By summarising the important issues of aggregate, particle size, water–cement ratio, additives and admixtures, mixing ratio design, mixing and moulding, and other factors that affect porosity, new design methods are proposed. A new effective stress model of pervious concrete based on continuous porosity and Terzaghi effective stress is developed which may fit the effective stress principle better. Finally, by summarising the research frontiers of pervious concrete, key issues that need to be addressed in future scientific research on pervious concrete are raised. [ABSTRACT FROM AUTHOR]

An ultrafine-grained Al71Ni14.5Co14.5/CNT poly-quasicrystal (QC/CNT) composite was synthesized using spark plasma sintering of powder components developed through electroless Ni-P/CNT plating of Co particles and mechanical alloying. The performance of the synthesized samples was studied using various testing methods, such as room temperature/hot compression, wear, and corrosion tests. The results were compared to the properties of alloy samples fabricated from raw and coated powders (without CNTs). The wear rate and friction coefficient of the quasicrystalline samples improved significantly due to the contribution of the CNTs. The wear rate of the CNT-containing specimens was 0.992 × 10−4 mm3/N/m, which is 47.1% lower than that of the QC sample. The positive impact of the CNTs on the corrosion potential and current density was further validated by the potentiodynamic polarization tests in a saline solution. However, these improvements in surface properties came at the cost of a 21.5% reduction in compressive strength, although the compressive strength still remained above 1.1 GPa at 600 °C. The results highlight an interesting trade-off between surface properties and mechanical strength, pointing toward the development of materials suitable for extreme conditions. [ABSTRACT FROM AUTHOR]

Solid polymer electrolytes (SPEs) show great promise for high-energy and high-safety lithium metal batteries. However, current SPEs suffer from low ionic conductivity and poor mechanical strength. Herein, the g-C3N4@COF heterojunction filler is constructed for SPEs for fast Li+ transport and high Li+ transference number. In addition, a robust 3D network is fabricated by using g-C3N4@COF heterojunction filler in order to further improve the mechanical robustness and electrochemical stability. As a consequence, the g-C3N4@COF-3D network/polymer electrolyte displays an ionic conductivity of 1.25×10−4 S cm−1 at 30 ℃, an electrochemical window of 5.0 V and the tensile strength of 8.613 MPa. Furthermore, the assembled LiFePO4//Li battery with the g-C3N4@COF-3D network/polymer electrolyte presents remarkable cycling stability with a capacity retention of 99.71% after 600 cycles. The above results indicate the great potential of the g-C3N4@COF-3D network/polymer electrolyte for advanced energy storage devices. [ABSTRACT FROM AUTHOR]

A novel acrylic monomer containing a nitrofuran motif, referred to as longchain nitrofuran methacrylate (LNFMA), is reported. In comparison to the previously reported nitrofuran methacrylate (NFMA), LNFMA has a longer side chain, and when incorporated into bone cement, the resulting LNFMA bone cement exhibits improved mechanical strength. At the same concentration, NFMA-5% cement has only 21.6 ± 1.3 MPa, while LNFMA-5% cement has a compressive strength of 42.64 ± 0.94 MPa. LNFMA bone cements exhibit antimicrobial activity against Staphylococcus aureus, with LNFMA-30% cement reaching 57.38% ± 5.53%. Moreover, LNFMA cement demonstrates excellent biocompatibility both in vitro and in vivo. The results showed that LNFMA monomer had optimized mechanical strength compared with previously reported NFMA monomers, and LNFMA bone cement had good antibacterial activity and biocompatibility. [ABSTRACT FROM AUTHOR]

Herein, we report a micro-tubular protonic ceramic fuel cell with novel bio-inspired four-channel structure, which has a considerable maximum output power density of 231 mW cm−2 and good long-term stability. [ABSTRACT FROM AUTHOR]

The current study aims to introduce a new polymeric composite consisting of epoxy resin as the matrix and gadolinium oxide (Gd2O3) as the neutron adsorption ingredient. The shielding performance of the composite was assessed by neutron attenuation experiments with an Am-Be source and polyethylene moderator. The results of these experiments showed an appreciable agreement with the Monte Carlo simulations. Other characteristics of the composite, including mechanical strength, thermal stability, microtexture, and its chemical compositions, were examined using standard tensile test, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, static light scattering analyses, and Fourier-transform infrared spectroscopy (FTIR). The results indicated that the new composites offer appreciable neutron absorption properties so that samples with 0.5%, 2%, 5%, and 10% Gd2O3 content could reduce the neutron beam intensity by 54%, 63%, 66%, and 70% at a thickness of 4 cm. [ABSTRACT FROM AUTHOR]

As demand for sustainable building materials rises, the use of waste rubber in civil engineering is gaining attention. This study proposes a method to modify waste rubber using polyvinyl alcohol (PVA) to enhance its material properties and expand its applications. A dataset was created focusing on the mechanical strength of cementitious materials incorporating PVA-modified waste rubber, and multiple machine learning methods were used to develop regression prediction models, particularly evaluating the support vector regression (SVR) model. Results show that the SVR model outperforms others, achieving mean squared errors of 1.21 and 0.33, and mean absolute errors of 2.06 and 0.15. Analysis indicates a negative correlation between waste rubber content and the water-to-cohesive ratio (w/c) with strength indexes, while a positive correlation exists between curing age and PVA. Notably, waste rubber content significantly affects strength. The mechanical strength of cementitious materials was notably enhanced by PVA-modified waste rubber, likely due to PVA's dispersion and bridging effects. This study presents a novel approach to sustainably recycle waste rubber, highlighting its potential in construction materials. [ABSTRACT FROM AUTHOR]

Recycled concrete incorporating additional super-absorbent polymer (SAP) and machine-made stone powder (MSP) was prepared using a two-factor, four-level orthogonal test. To enhance the frost resistance of recycled concrete and improve its mechanical properties, such as compressive and flexural strength, the prepared concrete underwent 200 freeze–thaw cycles. Before freeze–thaw cycles, the amount of SAP has a predominant influence on the mechanical properties of recycled concrete in comparison with MSP. After 200 cycles of freeze–thaw, the influence of MSP became more significant than that of SAP. Typically, the compressive strength and flexural strength exhibited a trend of initially increasing and then decreasing as the contents of SAP and MSP increased. The optimized recycled concrete was identified as S16M6, containing 0.16% SAP and 6% MSP, as demonstrated by the minimal strength loss after freeze–thaw cycles. This study also proposed a linear regression model for predicting the mechanical properties which offered valuable guidance for the engineering application of recycled concrete mixed with SAP under the freeze–thaw cycle environment. [ABSTRACT FROM AUTHOR]

Background: Bone grafts are extensively used for repairing bone defects and voids in orthopedics and dentistry. Moldable bone grafts offer a promising solution for treating irregular bone defects, which are often difficult to fill with traditional rigid grafts. However, practical applications have been limited by insufficient mechanical strength and rapid degradation. Methods: This study developed a ceramic composite bone graft composed of calcium sulfate (CS), β-tricalcium phosphate (β-TCP) with/without graphene oxide (GO) nano-particles. The biomechanical properties, degradation rate, and in-vitro cellular responses were investigated. In addition, the graft was implanted in-vivo in a critical-sized calvarial defect model. Results: The results showed that the compressive strength significantly improved by 135% and the degradation rate slowed by 25.5% in comparison to the control model. The addition of GO nanoparticles also improved cell compatibility and promoted osteogenic differentiation in the in-vitro cell culture study and was found to be effective at promoting bone repair in the in-vivo animal model. Conclusions: The mixed ceramic composites presented in this study can be considered as a promising alternative for bone graft applications. [ABSTRACT FROM AUTHOR]

In this study, the effect of curing temperature on mechanical strength and thermal properties of hydraulic limestone powder (LS) concrete is investigated. The hydration products and microstructure of hydraulic LS concrete are characterized through X-ray diffraction (XRD), thermogravimetry (TG), scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP). The results indicate that the mechanical strength decreases with an increase in the LS dosage. The largest mechanical strength at 3 and 7 d is recorded at the curing temperature of 50 °C, that at 28 and 90 d is obtained at 20 °C, whereas the lowest mechanical strength from 3 to 90 d is obtained at 5 °C. The thermal conductivity and thermal diffusivity of LS concrete are positively correlated with the compressive strength. The adiabatic temperature rise decreases with an increase in the LS dosage, and the largest temperature rise is obtained at the initial temperature of 5 °C, followed by those obtained at 20 and 50 °C. The longest fibrous C-S-H and thickest plate Ca(OH)2 with the largest size at 90 d is obtained at a curing temperature of 50 °C, followed by those obtained at 20 and 5 °C. The MIP results indicate that the largest total amount of gel pores and medium capillary pores at 90 d are obtained at a curing temperature of 20 °C, followed by 50 and 5 °C. [ABSTRACT FROM AUTHOR]

Based on the ultrasonic welding technology, this study uses three different welding widths to weld copper cables with different specifications. The influence of welding width on the mechanical properties and microstructure of each group of welded joints was systematically studied for the first time. The thermal shock test was carried out for each group of welded joints under optimum welding width to simulate the influence of severe temperature change environment on joint performance. It is found that the cross-sectional area of joint is 20 mm2 and optimal welding width of joint composed of two and three cables is 7 mm. The optimal welding temperature of the joint composed of four cables is 5 mm. Under the optimal welding width, the average shear strength of two-cable joint reaches 309.4 N. The four-cable joint is only 232.2 N. Moreover, the welding strength weakens significantly as the number of cables and the peak temperature decreases. The high temperature of bonding interface is the key factor to form a good weld. The peak temperature during welding is negatively correlated with the porosity of joint and positively correlated with peeling strength of joint. In addition, the morphology of ultrasonically welded joints has changed obviously after thermal shock test. With the participation of oxygen, the surface of welded joint is gray and bright brass, while the interior of joint is purple due to lack of oxygen. Moreover, the phenomenon of atomic diffusion and thermal expansion generates joints which were initially in a mechanically interlocked form and welding interface of the metallurgical bond under the action of high temperature. So the maximum joint peel strength is slightly improved. [ABSTRACT FROM AUTHOR]

The utilization of biofiber in recent years has significantly increased due to its advantages like being environmentally friendly, availability, and low costs. This paper investigates the physicochemical, mechanical, and morphological properties of the yucca fiber extracted by three methods such as water‐retting, traditional, and chemical methods. These analyses are designed to evaluate the extraction methodology and the hypothesis of the influence of harvesting location and growth conditions of the fiber. Various technologies are used, such as SEM, FTIR, XRD, and tensile tests. The fiber extracted by water retting is the strongest in the mechanical analysis with a strength of 690.48 MPa, followed by fiber extracted with the traditional method with 685.48 MPa, also 673.06, 657.94, 373.68 MPa for the fiber extracted by the chemical method using 3%, 5%, 10%NaOH respectively. The fiber obtained by the water retting method also has a higher chemical composition with 80.25% cellulose, 10.45% lignin, and 13.75% hemicellulose. The morphological characteristics are examined using Scanning Electron Microscopy. The crystallinity index ranged from 61.75% to 70.77%, and crystallite size from 1.73 to 2.04 nm is calculated from the XRD analysis. All these results confirm that yucca fiber can be a good sustainable choice for composite reinforcement. [ABSTRACT FROM AUTHOR]

Resin-based mortars are characterized by excellent strength parameters, together with very good chemical resistance and a short time to achieve installation and serviceability. However, a limitation of their use may be their relatively high curing shrinkage. This parameter can be improved by modifying the composition of mortars with, among other things, recycled materials. This article describes and compares the results of tests on four types of epoxy mor-tars: a control sample (unmodified) and three modified samples with waste polyethylene ter-ephthalate glycolysate, each one containing additional waste polyethylene or rubber from car tires. A positive effect on the mechanical strength of the mortars was demonstrated thanks to the modification. The shrinkage of the mortars was monitored from the time of formation. The partial substitution of aggregate by rubber granules or polyethylene agglomerate reduced the shrinkage value of the mortars based on a glycolysate-modified matrix by 14.2 % and 7.1 %, respectively.

Abstract The current study aims to introduce a new polymeric composite consisting of epoxy resin as the matrix and gadolinium oxide (Gd2O3) as the neutron adsorption ingredient. The shielding performance of the composite was assessed by neutron attenuation experiments with an Am-Be source and polyethylene moderator. The results of these experiments showed an appreciable agreement with the Monte Carlo simulations. Other characteristics of the composite, including mechanical strength, thermal stability, microtexture, and its chemical compositions, were examined using standard tensile test, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, static light scattering analyses, and Fourier-transform infrared spectroscopy (FTIR). The results indicated that the new composites offer appreciable neutron absorption properties so that samples with 0.5%, 2%, 5%, and 10% Gd2O3 content could reduce the neutron beam intensity by 54%, 63%, 66%, and 70% at a thickness of 4 cm.

Abstract Based on the ultrasonic welding technology, this study uses three different welding widths to weld copper cables with different specifications. The influence of welding width on the mechanical properties and microstructure of each group of welded joints was systematically studied for the first time. The thermal shock test was carried out for each group of welded joints under optimum welding width to simulate the influence of severe temperature change environment on joint performance. It is found that the cross-sectional area of joint is 20 mm2 and optimal welding width of joint composed of two and three cables is 7 mm. The optimal welding temperature of the joint composed of four cables is 5 mm. Under the optimal welding width, the average shear strength of two-cable joint reaches 309.4 N. The four-cable joint is only 232.2 N. Moreover, the welding strength weakens significantly as the number of cables and the peak temperature decreases. The high temperature of bonding interface is the key factor to form a good weld. The peak temperature during welding is negatively correlated with the porosity of joint and positively correlated with peeling strength of joint. In addition, the morphology of ultrasonically welded joints has changed obviously after thermal shock test. With the participation of oxygen, the surface of welded joint is gray and bright brass, while the interior of joint is purple due to lack of oxygen. Moreover, the phenomenon of atomic diffusion and thermal expansion generates joints which were initially in a mechanically interlocked form and welding interface of the metallurgical bond under the action of high temperature. So the maximum joint peel strength is slightly improved.

Abstract Background Bone grafts are extensively used for repairing bone defects and voids in orthopedics and dentistry. Moldable bone grafts offer a promising solution for treating irregular bone defects, which are often difficult to fill with traditional rigid grafts. However, practical applications have been limited by insufficient mechanical strength and rapid degradation. Methods This study developed a ceramic composite bone graft composed of calcium sulfate (CS), β-tricalcium phosphate (β-TCP) with/without graphene oxide (GO) nano-particles. The biomechanical properties, degradation rate, and in-vitro cellular responses were investigated. In addition, the graft was implanted in-vivo in a critical-sized calvarial defect model. Results The results showed that the compressive strength significantly improved by 135% and the degradation rate slowed by 25.5% in comparison to the control model. The addition of GO nanoparticles also improved cell compatibility and promoted osteogenic differentiation in the in-vitro cell culture study and was found to be effective at promoting bone repair in the in-vivo animal model. Conclusions The mixed ceramic composites presented in this study can be considered as a promising alternative for bone graft applications.

This study investigates the efficacy of silane-modified zeolite powder in enhancing the early age crack resistance of concrete. Three concrete mixes were evaluated: a reference mix, a 20 % zeolite replacement mix, and a silane-modified zeolite mix. The silane-zeolite mix demonstrated significant improvements, extending the time to crack by 70 % compared to the reference mix (from 11.2 to 19.1 hours). Mechanical strength tests revealed a 58 % increase in first-crack strength for the silane-zeolite mix over the reference mix. Water absorption tests showed that the silane-zeolite mix absorbed 42 % less water than the reference mix, indicating a denser microstructure. Microscopic analyses confirmed these findings, revealing a more refined pore structure with reduced microcrack frequency and width in the silane-zeolite mix. These results highlight the potential of silane-modified zeolite in improving concrete durability and longevity.

[Display omitted] The integration of flexible structure batteries (FSBs) into electronic equipment is an effective method to significantly improve energy efficiency, whereas traditional battery separators, with poor mechanical properties, low liquid electrolyte capture ability, and weak thermal stability, cannot meet the practical requirements of various applications. To address these challenges, in this study, a multifunctional composite quasi-solid-state electrolyte (CQE) was synthesized by electrospinning poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) fibers on both sides of an aramid nanofibers (ANFs) fibrous film for application in high-performance FSBs. Here, the ANF film serves as a structural framework, thus enhancing the mechanical properties and thermal stability of the CQE, while the "thermal closed-hole effect" and liquid electrolyte capture capability of the PVDF-HFP film in the CQE improve the overall safety of the FSBs. The design strategy of combining 3D-printed electrodes and functional CQE is essential to achieving the integration of structural support and energy storage. Due to the unique characteristics of the CQE, the assembled full-battery (LiFePO 4 //Li 4 Ti 5 O 12) demonstrates superior cycling stability (500 cycles). The assembled rectangular bag battery was also shown to be capable of powering an LED lamp under bending conditions and external force, thus providing valuable insights into FSBs design in the field of energy storage. [ABSTRACT FROM AUTHOR]

[Display omitted] • Introducing piezoelectric polymer aerogels into porous ceramics. • The average sound absorption coefficient reached 0.87. • Hierarchical pore structure and acoustic-electric conversion. • Composites possess strength, hydrophobicity and thermal insulation properties. Challenges remain in the design and manufacture of acoustic devices with excellent broadband sound absorption performance. Herein, an efficient acoustic absorber with hierarchical pore structure and additional acoustic-electrical energy conversion mechanism is reported in which combined zirconia porous ceramics and P(VDF-TrFE) piezoelectric aerogels. Reticular cross-scale pore structure enables sound waves to propagate and dissipate effectively. The vibrations generated by piezoelectric aerogels under acoustic excitation further consume sound waves through converting acoustic energy into electrical energy based on the local piezoelectric and triboelectric effect, which improves the medium and low-frequency sound absorption capability. The average sound absorption coefficient of the prepared acoustic composites reaches 0.87 while the noise reduction coefficient is 0.54. Furthermore, the composites also possess low density, high compressive strength, good hydrophobicity and thermal insulation properties for applications. Therefore, this innovative strategy offers new design ideas for the next generation of high-performance acoustic materials with promising applications in transportation and industrial construction. [ABSTRACT FROM AUTHOR]

Abstract Mechanical stability is one of the core capabilities of power transformers. External short‐circuit accidents are the main cause of winding instability. International Electrotechnical Commission 60076‐5 standard recommends a method to calculate the short‐circuit strength of power transformer windings by comparing the stress within windings under the effect of the maximum electromagnetic force with the critical stress of the winding. This method assumes that the maximum deformation will be produced by the maximum electromagnetic force, which corresponds to the first peak of the waveform. However, owing to the interactions between disks during the vibration process, the maximum deformation may occur after the occurrence of the maximum electromagnetic force. The hysteresis phenomenon between disk deformation and electromagnetic force is studied. The definition of the hysteresis phenomenon during the vibration process is first demonstrated, and the mechanism of the hysteresis phenomenon is investigated. The vibration model is established. By decoupling analysis, the conditions for the formation of hysteresis are proposed, and the mechanism of the hysteresis phenomenon is validated by the experiment, which is conducted on a winding sample. In the deformation formula, the term that determines the time‐varying characteristic is found. The waveform‐determining term is the difference between the two cosine components, whose frequencies are the natural vibration frequency and the electromagnetic force frequency. When the two frequencies are close, the maximum deformation lags behind the maximum force, and the hysteresis phenomenon occurs.

Abstract This study focuses on the design and preparation of a thin-walled plastic chair, and its mechanical properties were investigated by high load, cyclic load and drop impact. The finite element method (FEM) was employed to accurately evaluate the chair’s safety under these forces. Additionally, the effects of important structural parameters on the loading process in different states were investigated. Furthermore, a solid plastic chair prototype was created for experimental analysis. The findings revealed that increasing the thickness of the key structural parameters enhanced the safety properties of the chair under various load conditions. Optimal results were obtained when both dimensions were set to 5 mm. The deformation errors in FEM, experimental strength analysis, fatigue analysis, and drop impact analysis were measured at 3.7%, 3.6%, and 11.7%, respectively. Similarly, the stress errors were determined to be 5.9%, 5.2%, and 6.5%. These results suggest that the structural design of the chair demonstrates excellent reliability. Studying the crucial structural parameters of a plastic chair can provide valuable insights for the scientific design and safety evaluation of thin-walled furniture.

Abstract Background Bisphosphonate (BP) can treat osteoporosis and prevent osteoporotic fractures in clinical. However, the effect of BP on microstructure and mechanical properties of cortical and trabecular bone has been taken little attention, separately. Methods In this study, BP was used to intervene in ovariectomized female SD rats. The femoral micro-CT images were used to measure the structural parameters and reconstruct the 3D models in volume of interest. The structural parameters of cortical and trabecular bone were measured, and the mechanical properties were predicted using micro-finite element analysis. Results There was almost no significant difference in the morphological structure parameters and mechanical properties of cortical bone between normal, ovariectomized (sham-OVX) and BP intervention groups. However, BP could significantly improve bone volume fraction (BV/TV) and trabecular separation (Tb.SP) in inter-femoral condyles (IT) (sham-OVX vs. BP, p

For marine soft soil under the periodic wave loading, the pore water content in soil suffering dry-wet cycle for a long time, which affects its microstructure and macroscopic mechanical strength, resulting in insufficient bearing capacity and excessive deformation of soft soil. To reveal the microstructural characteristics and strength attenuation law of marine soft soil under dry-wet cycle condition, electron microscopy scanning and direct shear tests under different times of dry-wet cycles were carried out, and the mathematical equations of pore structure and strength parameters were established based on fractal theory. The research results showed that: (1) The pore structure changed considerably after the first dry-wet cycle, and then changed gently with the increase of dry-wet cycle times, which was reflected by the fractal dimension D value decreases to a constant value gradually. (2) The shear strength of the soil diminishes with an increase in the number of dry-wet cycle times, and the maximum attenuation occurs after the first dry-wet cycle. (3) The relationship between cohesion (c), internal friction angle (φ), and fractal dimension (D) is exponential, with the curve shapes being concave and convex, respectively.

A new type of ternesite-ye'elimite (TCSA) cement was prepared with different amounts of ternesite. The effect of the ternesite content on the mechanical properties and hydration products of cement pastes was studied. The influence of the added gypsum content on the performance of TCSA cement was also discussed. The results showed that increasing the contents of ternesite prolonged the setting times of the TCSA clinkers. Increasing the ternesite content promoted the strength development. The increase in the ternesite content caused the lower expansion of the TCSA clinkers. The formation of ettringite, stratlingite and monosulfate was observed in the hydrated clinker pastes. The amount of stratlingite and monosulfate decreased at 28 days, while the formation of ettringite continued to increase due to the hydration of ternesite. The higher added gypsum content increased the compressive strength between 1 and 28 d. However, 15% gypsum was not conducive to the strength development at later ages. In the presence of gypsum, the formation of stratlingite was not observed. A higher gypsum content favoured ettringite precipitation at 1 d, but excess gypsum hindered the ternesite hydration.

Our comprehensive review plunges into the cutting-edge advancements of polymeric microneedle drug delivery systems, underscoring their transformative potential in the realm of transdermal drug administration. Our scrutiny centers on the substrate materials pivotal for microneedle construction and the core properties that dictate their efficacy. We delve into the distinctive interplay between microneedles and dermal layers, underscoring the mechanisms by which this synergy enhances drug absorption and precision targeting. Moreover, we examine the acupoint–target organ–ganglion nexus, an innovative strategy that steers drug concentration to specific targets, offering a paradigm for precision medicine. A thorough analysis of the clinical applications of polymeric microneedle systems is presented, highlighting their adaptability and impact across a spectrum of therapeutic domains. This review also accentuates the systems' promise to bolster patient compliance, attributed to their minimally invasive and painless mode of drug delivery. We present forward-looking strategies aimed at optimizing stimulation sites to amplify therapeutic benefits. The anticipation is set for the introduction of superior biocompatible materials with advanced mechanical properties, customizing microneedles to cater to specialized clinical demands. In parallel, we deliberate on safety strategies aimed at boosting drug loading capacities and solidifying the efficacy of microneedle-based therapeutics. In summation, this review accentuates the pivotal role of polymeric microneedle technology in contemporary healthcare, charting a course for future investigative endeavors and developmental strides within this burgeoning field. [ABSTRACT FROM AUTHOR]

Al 2 O 3 reticulated porous ceramics (ARPCs) are extensively employed in high-temperature catalytic support, molten metal filtration, and porous media combustion because of their high specific surface area and heat resistance. The high specific surface area is usually maintained by high apparent porosity, but unfortunately, the accompanying poor mechanical properties severely compromise the durability of ARPCs. To synergistically improve the mechanical properties and apparent porosity, a new strategy was proposed to prepare ARPCs with textured structures of in situ interlocking Al 2 O 3 platelet integration using vacuum impregnation Na 3 AlF 6 –SiC–Al 2 O 3 slurry technique. The obtained textural structure had a significant strengthening effect on ARPCs, attributed to the increased contact area among non-equiaxed grains, and the compact growth of Al 2 O 3 platelets with high aspect ratios provided the high apparent porosity and specific surface area of ARPCs, resulting in compressive strength as high as 3.93 MPa at an apparent porosity of 85.31 %, as well as the degradation of Congo red up to 75.35 % due to the Al 2 O 3 platelets facilitating the loading of TiO 2. [ABSTRACT FROM AUTHOR]

Background: Bisphosphonate (BP) can treat osteoporosis and prevent osteoporotic fractures in clinical. However, the effect of BP on microstructure and mechanical properties of cortical and trabecular bone has been taken little attention, separately. Methods: In this study, BP was used to intervene in ovariectomized female SD rats. The femoral micro-CT images were used to measure the structural parameters and reconstruct the 3D models in volume of interest. The structural parameters of cortical and trabecular bone were measured, and the mechanical properties were predicted using micro-finite element analysis. Results: There was almost no significant difference in the morphological structure parameters and mechanical properties of cortical bone between normal, ovariectomized (sham-OVX) and BP intervention groups. However, BP could significantly improve bone volume fraction (BV/TV) and trabecular separation (Tb.SP) in inter-femoral condyles (IT) (sham-OVX vs. BP, p < 0.001), and had no significant effect on BV/TV in medial and lateral femoral condyles (MT, LT). Similarly, BPs could significantly affect the effective modulus in IT (sham-OVX vs. BP, p < 0.001), and had no significant difference in MT and LT. In addition, the structural parameters and effective modulus showed a good linear correlation. Conclusion: In a short time, the effects of BP intervention and osteoporosis on cortical bone were not obvious. The effects of BP on trabecular bone in non-main weight-bearing area (IT) were valuable, while for osteoporosis, the main weight-bearing area (MT, LT) may improve the structural quality and mechanical strength of trabecular bone through exercise compensation. [ABSTRACT FROM AUTHOR]

Mechanical stability is one of the core capabilities of power transformers. External short‐circuit accidents are the main cause of winding instability. International Electrotechnical Commission 60076‐5 standard recommends a method to calculate the short‐circuit strength of power transformer windings by comparing the stress within windings under the effect of the maximum electromagnetic force with the critical stress of the winding. This method assumes that the maximum deformation will be produced by the maximum electromagnetic force, which corresponds to the first peak of the waveform. However, owing to the interactions between disks during the vibration process, the maximum deformation may occur after the occurrence of the maximum electromagnetic force. The hysteresis phenomenon between disk deformation and electromagnetic force is studied. The definition of the hysteresis phenomenon during the vibration process is first demonstrated, and the mechanism of the hysteresis phenomenon is investigated. The vibration model is established. By decoupling analysis, the conditions for the formation of hysteresis are proposed, and the mechanism of the hysteresis phenomenon is validated by the experiment, which is conducted on a winding sample. In the deformation formula, the term that determines the time‐varying characteristic is found. The waveform‐determining term is the difference between the two cosine components, whose frequencies are the natural vibration frequency and the electromagnetic force frequency. When the two frequencies are close, the maximum deformation lags behind the maximum force, and the hysteresis phenomenon occurs. [ABSTRACT FROM AUTHOR]

The release of Neogene volcanism in the southeastern part of the Iberian Peninsula produced a series of volcanic structures in the form of stratovolcanoes and calderas; however, other materials also accumulated such as large amounts of pyroclastic materials such as cinerites, ashes, and lapilli, which were later altered to form deposits of zeolites and bentonites. This work has focused on an area located on the northern flank of the San José-Los Escullos zeolite deposit, the only one of its kind with industrial capacity in Spain. The main objective of this research is to characterize the zeolite (SZ) of this new area from the mineral, chemical, and technical points of view and establish its possible use as a natural pozzolan. In the first stage, a study of the mineralogical and chemical composition of the selected samples was carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray fluorescence (XRF), and thermogravimetric analysis (TGA); in the second stage, chemical-qualitative and pozzolanicity technical tests were carried out at 8 and 15 days. In addition, a chemical analysis was performed using XRF on the specimens of mortars made with a standardized mixture of Portland cement (PC: 75%) and natural zeolite (SZ: 25%) at the ages of 7, 28, and 90 days. The results of the mineralogical analyses indicated that the samples are made up mainly of mordenite and subordinately by smectite, plagioclase, quartz, halloysite, illite, and muscovite. Qualitative chemical assays indicated a high percentage of reactive silica and reactive CaO and also negligible contents of insoluble residues. The results of the pozzolanicity test indicate that all the samples analyzed behave like natural pozzolans of good quality, increasing their pozzolanic reactivity from 8 to 15 days of testing. Chemical analyses of PC/SZ composite mortar specimens showed how a significant part of SiO2 and Al2O3 are released by zeolite while it absorbs a large part of the SO3 contained in the cement. The results presented in this research could be of great practical and scientific importance as they indicate the continuation of zeolitic mineralization beyond the limits of the San José-Los Escullos deposit, which would result in an increase in geological reserves and the extension of the useful life of the deposit, which is of vital importance to the local mining industry. [ABSTRACT FROM AUTHOR]

Silica fume (SF) is an essential component in ultra-high-performance concrete (UHPC) to compact the matrix, but the nucleus effect also causes rapid hydration, which results in high heat release and large shrinkage. In this paper, the carboxylic agents, including polyacrylic acid and polycarboxylate superplasticizer, were used to surface modify SF to adjust the activity to mitigate hydration at an early time and to promote continuous hydration for a long period. The surface and dispersion properties of modified SF (MSF), as well as the strength and pore structure of UHPC, were studied, and the stability of the modification was also investigated. The results demonstrated that, after treatment, the carboxylic groups were grafted on the SF surface, the dispersion of SF was improved due to the increased negative pentanal of the particle surface and the steric hindrance effect, the early hydration was delayed about 3–5 h, and the hydration heat release was also mitigated. The compressive strength of UHPC with MSF reached a maximum of 138.7 MPa at 3 days, which decreased about 3.7% more than the plain group, while flexural strength varied insignificantly. More pores and cracks were observed in the matrix with MSF, and the hydration degree was promoted with MSF addition. The grafted group on SF fell off under an alkali environment after 1 h. [ABSTRACT FROM AUTHOR]

This study presents the feasibility of improving some selected mechanical strengths and the inner-structural analyses of cement matrix by electrospun nanofibers containing nylon 66, nanosilica, and carbon nanotube. The hybrid electrospun nanofibers were fabricated and mixed into ordinary Portland cement. From the mechanical strength test results, the hybrid nanofibers have shown their role in improving the tensile, compressive, and toughness behavior of the mixed cement material. The improvements of 62%, 38%, and 69%, respectively, were observed compared to those of the control paste. The novelty of the surface and inner structure of the hybrid fibers, as well as the modified cement matrix, were observed by the scanned images from electron microscopes. Besides, the additional pozzolanic reaction between the generated calcium hydroxide and the attached silica was clarified thanks to the results of energy dispersive spectroscopy, X-ray diffraction, and thermal gravimetric analysis. Finally, the consistency between mechanical strength results and inner-structure analyses showed the potential of the proposed fiber to improve cement-based materials. [ABSTRACT FROM AUTHOR]

Phosphogypsum (PG) is an industrial solid waste generated during the preparation of phosphoric acid, which is produced in large quantities and stockpiled or discharged into the sea. This study aims to design sustainable pavement base materials constituting significant PG content. The physical and chemical properties of the raw materials were first tested. The optimum moisture content and maximum dry density of specimens were determined by compaction tests. The unconfined compressive strength (UCS), split tensile strength (STS), freeze-thaw cycles, and shrinkage tests were used to evaluate the mechanical performance of phosphogypsum pavement base material (PPBM). Furthermore, the interaction mechanism was investigated by applying scanning electron microscope (SEM) and Fourier-transformed infrared (FTIR) tests. The results showed that the 7-day UCS of PPBM with cement content 8%–12% was greater than 3 MPa. The specimens retained 91.3% unconfined compressive strength over five freeze-thaw cycles. Unlike traditional semirigid base materials, the PPBM exhibited no shrinkage strain, which is manifested by the growth of expansion strain with increasing amounts of PG. Through microscopic observation, the PPBM produced ettringite (AFt) and calcium-silicate-hydrate (CSH) with the extension of curing time, which is consistent with the analysis of FTIR spectrums. The crystallized water in the PG participates in the hydration reaction. [ABSTRACT FROM AUTHOR]

For marine soft soil under the periodic wave loading, the pore water content in soil suffering dry-wet cycle for a long time, which affects its microstructure and macroscopic mechanical strength, resulting in insufficient bearing capacity and excessive deformation of soft soil. To reveal the microstructural characteristics and strength attenuation law of marine soft soil under dry-wet cycle condition, electron microscopy scanning and direct shear tests under different times of dry-wet cycles were carried out, and the mathematical equations of pore structure and strength parameters were established based on fractal theory. The research results showed that: (1) The pore structure changed considerably after the first dry-wet cycle, and then changed gently with the increase of dry-wet cycle times, which was reflected by the fractal dimension D value decreases to a constant value gradually. (2) The shear strength of the soil diminishes with an increase in the number of dry-wet cycle times, and the maximum attenuation occurs after the first dry-wet cycle. (3) The relationship between cohesion (c), internal friction angle (φ), and fractal dimension (D) is exponential, with the curve shapes being concave and convex, respectively. [ABSTRACT FROM AUTHOR]

Conductive hydrogels combine the properties of both hydrogels and conductors, making them soft, flexible, and biocompatible. These properties enable them to conform to irregular surfaces, stretch and bend without losing their electrical conductivity, and interface with biological systems. Conductive hydrogels can be utilized as conductive traces, electrodes, or as a matrix for flexible electronics. Exciting applications in sensors, tissue engineering, and human-machine interaction have been demonstrated worldwide. This review comprehensively covers the progress in this field, focusing on several main aspects: functional materials, performance improvement strategies, and wearable applications in human-related areas. Furthermore, the major approaches and challenges for improving their mechanical properties, conductivity, and long-term stability are systematically summarized. [ABSTRACT FROM AUTHOR]

Rubberized cement-based materials are widely utilized because of their good ductility, impact resistance, and fatigue resistance. This research investigated the effect of the rubber aggregates content, particle size of rubber aggregates, and water–cement ratio on the early-age mechanical properties and deformation behaviors of mortar through laboratory tests, and strength reduction coefficient fitting models were established according to the testing results. The results show that the compressive strength growth rate of cement mortar is about 15% slower than that of flexural strength. The existence of rubber aggregates lowers the strength increase rate of mortar. The reduction coefficient of strength decreases with increasing rubber aggregates content and increases with the age of mortar. Increasing rubber aggregates content and decreasing particle size of rubber aggregate can lower the autogenous shrinkage in the initial stage, but the autogenous shrinkage of the later stage increases as the rubber aggregates content increases, with a turning point between 30 h and 50 h. After 3 days, the dry shrinkage of mortar accounts for about 70–80% of the total shrinkage, and it increases with higher rubber aggregate content, smaller particle size of rubber aggregates, and higher water–cement ratios. [ABSTRACT FROM AUTHOR]

Reliability analysis of mechanical strength could be used for evaluation of wood scrimber properties in this study. Normal, lognormal, and Weibull distributions were used to determine and selected the optimal model for wood scrimber for the first time. The results of reliability analysis indicated that the bending and tensile strength were well fit for normal distribution. Weibull distribution could describe the probability distribution law of compression strength, and lognormal distribution could reflect the probability distribution law of shear strength, respectively. The standard value of each mechanical strength was determined and compared in accordance with two methods. This illustrated that a significant difference between these two methods is evident in the case of modulus of elasticity (MOE), compression strength (CS), and shear strength (SS), while modulus of rupture (MOR) and tensile strength (TS) yielded similar data. The improvement in mechanical strengths was remarkably affected by the increase in density. Moreover, the microstructure of wood scrimber has a good ratio of deformation with respect to density, which can be significantly explained by compressive densification. The results suggest that the deformation ratio increased from 49.75% to 78.67%, which might reflect the variation in macroscopic mechanical strength of wood scrimber. [ABSTRACT FROM AUTHOR]

To promote the use of solid waste in concrete production and solve the problem of secondary pollution caused by a large amount of solid waste, the four-factor and four-level orthogonal test method was used to investigate the different replacement rates of coal gangue (CG) ceramics (15%, 20%, 25%, and 30%), coal gangue ceramic sand (CGS) (10%, 15%, 20%, and 25%), fly ash (FA) (10%, 15%, 20%, and 25%), and steel fiber (SF) content (0.30%, 0.60%, 0.90%, and 1.2). By using range analysis, variance analysis, matrix analysis, and regression analysis, the prediction models of primary and secondary factors, optimal dosage, and strength under different factor levels were obtained. The microstructure and strengthening mechanisms of different materials were analyzed by scanning electron microscopy (SEM). The results show that the optimal combination of the CG substitution rate is 30%, CGS substitution rate is 15%, SF content is 1.2%, and FA substitution rate is 10% for cube compressive strength. For the splitting tensile strength, the optimal combination is a CG substitution rate of 30%, CGS substitution rate of 25%, SF content of 1.2%, and FA substitution rate of 10%. The resulting strength prediction model has high accuracy, which can predict the strength within the range selected by the orthogonal test in this paper and provide a reference for the application of steel fibers and solid waste in concrete, which contributes to the energy conservation and emission reduction in the construction industry. [ABSTRACT FROM AUTHOR]

In this study, Poly(vinyl alcohol)/cellulose nanofiber (PVA/CNF) hydrogels have been successfully prepared using γ-ray irradiation, annealing, and rehydration processes. In addition, the effects of CNF content and annealing methods on the hydrogel properties, including gel fraction, micromorphology, crystallinity, swelling behavior, and tensile and friction properties, are investigated. Consequently, the results show that at an absorbed dose of 30 kGy, the increase in CNF content increases the gel fraction, tensile strength, and elongation at break of irradiated PVA/CNF hydrogels, but decreases the water absorption. In addition, the cross-linking density of the PVA/CNF hydrogels is significantly increased at an annealing temperature of 80 °C, which leads to the transition of the cross-sectional micromorphology from porous networks to smooth planes. For the PVA/CNF hydrogel with a CNF content of 0.6%, the crystallinity increases from 19.9% to 25.8% after tensile annealing of 30% compared to the original composite hydrogel. The tensile strength is substantially increased from 65.5 kPa to 21.2 MPa, and the modulus of elasticity reaches 4.2 MPa. Furthermore, it shows an extremely low coefficient of friction (0.075), which suggests that it has the potential to be applied as a material for artificial joint cartilage. [ABSTRACT FROM AUTHOR]

Low-cost and high-performance materials or techniques that could synergistically remove phenanthrene (PHE) in a simple manner were highly desired. Herein, we reported an alkali-activated slag (AAS) that proved applicable in both construction and environmental protection efforts. AAS was synthesized by mixing ground granulated blast furnace slag (GGBFS) and an alkaline solution. The prepared AAS mortar achieved the highest mechanical strength when using an alkaline activator with a Na2O concentration of 8% by slag weight. Moreover, AAS exhibited excellent sorption performance towards PHE, with the highest sorption performance reaching 44.0 mg/g, which was much higher than that of GGBFS. Sorption of PHE reached equilibrium within approximately 120 h and fit well with the pseudo-second-order model. Furthermore, the primary sorption mechanisms for PHE on AAS were attributed to cation-π interactions, hydrogen bonding, and flocculation. The strategy of using AAS not only met the requirements for high-performance and low-cost materials but also addressed the challenging issues of developing an all-in-one treatment for PHE pollutants, which was of great significance to wastewater purification. [ABSTRACT FROM AUTHOR]

The intricate composition of wastewater impedes the recycling of agricultural and industrial effluents. This study aims to investigate the potential of sisal leaf wastewater (SLW), both water-treated (WTSLW) and alkali-treated (ATSLW), as a substitute for the alkali activator (NaOH solution) in the production of slag-powder- and fly-ash-based composites, with a focus on the effects of WTSLW substitution ratios and sisal leaf soaking durations. Initially, the fresh properties were assessed including electrical conductivity and fluidity. A further analysis was conducted on the influence of both WTSLW and ATSLW on drying shrinkage, density, and mechanical strength, including flexural and compressive measures. Microstructural features were characterized using SEM and CT imaging, while XRD patterns and FTIR spectra were employed to dissect the influence of WTSLW substitution on the composite's products. The results show that incorporating 14 wt% WTSLW into the composite enhances 90-day flexural and compressive strengths by 34.8% and 13.2%, respectively, while WTSLW curtails drying shrinkage. Conversely, ATSLW increases porosity and decreases density. Organic constituents in both WTSLW and ATSLW encapsulated in the alkaline matrix fail to modify the composites' chemical composition. These outcomes underscore the potential for sustainable construction materials through the integrated recycling of plant wastewater and solid by-products. [ABSTRACT FROM AUTHOR]