Mechanical Strength Research Articles

Mechanical strength of lightweight cylindrical aggregates

Mechanical strength of lightweight cylindrical aggregates

Metal Organic Framework Impregnated Nanofibrous Aerogels: A 3D Structured Matrix for CO2 Capture.

This study explores the synthesis and functionality of mesoporous UiO-66-NH2 metal-organic framework (MOF) impregnated cellulose diacetate (CDA)-silica hybrid nanofibrous aerogels (NFAs) for selective CO2 capture. Mesoporous MOFs generally outperform microporous MOFs for CO2 capture, while NFAs provide a lightweight, highly porous material platform consisting of a three-dimensional (3D) network of interlinked nanofibers, offering both mechanical strength and a larger surface area. We exploit the attributes of these candidate materials by producing CDA-silica@UiO-66-NH2 NFA through a simple freeze-drying process involving a mixture of CDA-silica nanofiber dispersions and mesoporous UiO-66-NH2 nanoparticles in tert-butanol, avoiding cumbersome pre- or postprocessing typical in aerogel synthesis. The aerogels exhibit a hierarchical porous structure, allow for MOF loadings of up to 80 wt %, and demonstrate remarkable CO2 adsorption performance, with a direct correlation between MOF content and adsorption efficiency. Notably, an NFA containing 80 wt % MOF achieves a CO2 uptake of 2.5 mmol/g at 35 °C and atmospheric pressure. The CDA-silica@UiO-66-NH2 NFA also exhibits a strong preference for CO2 adsorption compared to N2 across all pressure levels when exposed to a gas mixture of CO2 and N2 in an 85:15 ratio. The CO2/N2 selectivity (Sads) usually calculated by using the ideal adsorption solution theory (IAST) reveals a value of 18.2 at 298 °K for this system. The NFA also displays strong mechanical resiliency including compressibility and fatigue resistance, and MOF integration without detachment during multiple compression cycles. Unlike traditional CO2 capture materials, our CDA-silica@UiO-66-NH2 NFA with a combination of high CO2 selectivity, structural integrity, and ease of fabrication thus offers a potentially scalable solution that addresses both performance and durability in real-world applications.

A Robust and Tough Composite Hydrogel Electrolyte with Anion-Locked Supramolecular Network for Zinc Ion Batteries.

Hydrogel electrolytes have garnered extensive attention in zinc ion batteries due to their excellent flexibility and good safety. However, their limited mechanical properties, low ionic conductivity, and poor Zn2+ transference number pose significant challenges for developing high-performance zinc ion batteries. Herein, this work constructs a 3D supramolecular network capable of locking anions and active water molecules through the abundant hydrogen bonding interactions between aramid nanofibers, polyvinyl alcohol, and anions. This network synergistically enhances the mechanical properties (with a mechanical strength of 0.88MPa and a toughness of 3.28MJ m-3), ionic conductivity (4.22 S m-1), and Zn2+ transference number (0.78). As a result, the supramolecular composite hydrogel electrolyte can effectively inhibit dendrite growth and side reactions, facilitate interface regulation, and enable uniform zinc deposition. The Zn anode exhibits a cycle life of 1500h at 5mA cm-2 and 5 mAh cm-2, with an average coulombic efficiency of 99.1% over 600 cycles. Additionally, the Zn||polyaniline full cell maintains a high capacity retention of 78% after 9100 cycles at 1 A g-1. The assembled pouch cells demonstrate good flexibility, deformability, and compression resistance. This work provides valuable insights into the design of high-performance hydrogel electrolytes for zinc ion batteries.

Boosting Ni-Rich Cathode Stability Through Grain Boundary Strengthening and Phase Transition Degradation Suppression.

Nickel-rich layered cathodes are promising for high-energy-density lithium-ion batteries but suffer from rapid capacity fading, primarily due to intergranular cracking and structural degradation during the H2-H3 phase transition, especially under high voltage. To address these challenges, a novel Ta5+/Ti4+ co-doping strategy has been introduced that simultaneously stabilizes grain boundaries and enhances the mechanical strength of the cathode. The dopants effectively mitigate intergranular cracking and form a pre-cation-mixing layer, stabilizing the layered structure during deep delithiation and preventing structural collapse. Moreover, this co-doping approach also improves the reversibility of the H2-H3 phase transition and reduces lattice distortions, thereby enhancing cycling stability. As a result, the co-doped cathode exhibits excellent capacity retention of 96.66% after 150 cycles at 1 C in liquid electrolyte. In solid-state batteries, it demonstrates superior interfacial compatibility with significantly reduced side reactions with the solid electrolyte, achieving a high initial capacity of 181.4 mAh g-1 and retaining 89.3% of its capacity after 100 cycles. This marks a significant improvement over the pristine cathode. These results highlight the effectiveness of Ta5+/Ti4+ co-doping as a pratical strategy for developing high-performance nickel-rich cathodes for next-generation lithium-ion batteries.

Mechanical analysis and sensitivity evaluation of PLA scaffolds for bone tissue repair using FEA and Taguchi experimental design.

Purpose: The design of three-dimensional scaffolds for bone regeneration poses challenges in balancing mechanical strength, porosity and degradability. This study aimed to optimize the geometric parameters of polylactic acid (PLA) scaffolds fabricated via 3D printing, focusing on pore size, porosity, and geometric configurations to enhance mechanical performance and biological functionality. Methods: Two geometric configurations - orthogonal and offset orthogonal - were evaluated with pore sizes ranging from 400-1000 µm and porosities between 55-70%. Finite element analysis (FEA) in ANSYS Workbench was used to simulate mechanical behavior, while the Taguchi experimental design determined the optimal parameter combinations. Statistical analyses, including ANOVA, assessed the significance of each factor. Results: The study identified a pore size of 400 µm as optimal for structural strength, while a porosity of 70% provided a balance between stability and cell growth. Orthogonal geometries distributed stress more uniformly, reducing critical stress concentrations compared to offset configurations. ANOVA revealed that pore size was the most significant factor, followed by porosity and geometry, achieving a model reliability of R 2 = 98.42%. Conclusions: The findings highlight the importance of geometric optimization for improving scaffold mechanical properties while maintaining biological functionality. This study offers a robust framework for designing patient-specific scaffolds tailored to bone tissue engineering applications.

Transversalis fascia collagen content and the risk of surgical complications: results of a prospective study

BackgroundCollagen is the major protein of the extracellular matrix that provides mechanical strength to the tissues. The relationship between the development of complications and the quality and quantity of collagen fibres has not been investigated in the literature, yet.MethodsThis was a prospective study of 392 patients who underwent subcostal laparotomy for confirmed or suspected gastrointestinal malignancy. Prior to abdominal closure a sample of transversalis fascia was collected. The area covered by collagen (ACC) was measured as the mean area covered by Picosirius stained fibres in three areas of the fascia. The primary endpoint of the study was the occurrence of complications, graded according to the Clavien-Dindo over a 90-day follow-up period.Results392 patients were included in the study. A transversalis fascia sample was obtained in 354 patients (90.3%) and image assessment yielded a group of 259 specimens that were included in the analysis (66.1%). Predicting the development of complications of at least CD III based on ACC was associated with an AUC of 0.606 (p = 0.027) and an optimal threshold of 0.771. There were significantly fewer complications of at least CD III in the group of patients with ACC ≥ 0.771 (6/125) than in the group below the threshold (25/134) (p < 0.01).ConclusionsCollagen content may serve as an adjunct predictor of surgical risk, although its clinical utility requires further validation. There is a need for further studies on the causal nature of this relationship and modifiable risk factors related to body collagen quality.

Mechanically Strong Nanocolloidal Supramolecular Plastics Assembled from Carbonized Polymer Dots with Photoactivated Room-Temperature Phosphorescence.

The innovative development of supramolecular plastics (SPs) is recognized as one of the global efforts to address the environmental pollution caused by petroleum-based plastics. Traditional SPs usually show weak mechanical strength because of relatively weak noncovalent bonds and a lack of appropriate functions for practical applications. To overcome these limitations, we herein report nanocolloidal supramolecular plastics (NSPs) assembled from newly emerging nanoparticles, namely, carbonized polymer dots (CPDs) modified with ureido pyrimidinone groups. These NSPs display good mechanical properties, unique photoactivated room-temperature phosphorescence (RTP), and excellent solvent stability. Notably, NSPs are recyclable with maintenance of their original mechanics and photoactivated RTP after several usages. Furthermore, photoactivated RTP with multiple colors is achieved by incorporating organic molecules into NSPs. We show proof-of-concept applications of NSPs in high-level information security. The results in this work pave an avenue toward functional materials assembled from CPDs and will advance the development of innovative nanomaterials for sustainable applications.

Hierarchical design of silkworm silk for functional composites.

Silk-reinforced composites (SRCs) manifest the unique properties of silkworm silk fibers, offering enhanced mechanical strength, biocompatibility, and biodegradability. These composites present an eco-friendly alternative to conventional synthetic materials, with applications expanding beyond biomedical engineering, flexible electronics, and environmental filtration. This review explores the diverse forms of silkworm silk fibers including fabrics, long fibers, and nanofibrils, for functional composites. It highlights advancements in composite design and processing techniques that allow precise engineering of mechanical and functional performance. Despite substantial progress, challenges remain in making optimally functionalized SRCs with multi-faceted performance and understanding the mechanics for reverse-design of SRCs. Future research should focus on the unique sustainable, biodegradable and biocompatible advantages and embrace advanced processing technology, as well as artificial intelligence-assisted material design to exploit the full potential of SRCs. This review on SRCs will offer a foundation for future advancements in multifunctional and high-performance silk-based composites.

An anisotropic strategy for developing polymer electrolytes endowing lithium metal batteries with electrochemo-mechanically stable interface

Developing versatile solid polymer electrolytes is a reasonable approach to achieving reliable lithium metal batteries but is still challenging due to the nonuniform lithium deposition associated with the sluggish Li+ kinetics and insufficient mechanical strength. Herein, the concept of developing anisotropic solid polymer electrolyte is realized via integrating polymer hosts with highly oriented polyacrylonitrile nanofibers modified by Li6.4La3Zr1.4Ta0.6O12 particles. The oriented composite structure is employed to homogenize Li+ flux, serving as a physical barrier to resist lithium dendrites, retarding the side reaction between the electrolyte and lithium, thus endowing a compatible interface for lithium negative electrode. Correspondingly, the Li | |LiFePO4 cells steadily operate over 1000 cycles, delivering durable capacity retention of 91% at 170 mA g-1. Furthermore, numerical modeling and density functional theory are combined to clarify the multiphysics interplay between the designed solid polymer electrolyte and lithium negative electrode. This work provides a perspective for constructing interface-friendly solid polymer electrolytes at an electrochemo-mechanical level.

Design of Hydrogel Electrolytes Using Strong Bacterial Cellulose with Weak Ionic Interactions.

Hydrogel electrolytes with both high ionic conductivity and sufficient mechanical strength are in great demand but remain a long-standing challenge. Here, we report a simple method to fabricate highly conductive and strong hydrogels (IBVA) by leveraging a layered cellulose network with weak ionic interactions. Specifically, bacterial cellulose (BC) membranes with high crystallinity and mechanical strength are employed as the strong skeletons of the hydrogel matrix. Simultaneously, formate anions with a salting-in effect are introduced to tune the aggregation states of polymer chains, endowing the hydrogel with weak hydrogen bonding, and finally forming a "hard-soft-hard" interlocking hierarchical structure. This strategy enables the hydrogel to achieve an ultrahigh ionic conductivity of 105 ± 5 mS cm-1, alongside satisfying mechanical strength (0.78 MPa), outperforming most reported hydrogel electrolytes. Furthermore, the IBVA hydrogel was successfully demonstrated as an electrolyte for supercapacitors, exhibiting the favorable flexibility, broad temperature adaptability, interfacial stability, and stable electrochemical performance. Our proposed method establishes a framework for engineering high-performance hydrogel electrolytes tailored for flexible electronics.

Assessing the Potential of Lateritic Clayey Soils for Road Infrastructure in Tropical Regions

Lateritic soils, characterized by complex mineralogy, a high degree of weathering, and a distinctive structure, are widely distributed in tropical regions. However, their use in pavement layers is often restricted due to conservative soil classification methods that may not fully represent their mechanical potential. This study evaluates the geotechnical behavior of a lateritic clay from a small town in São Paulo, referred to in this article as Purple Clay, with a focus on its permanent deformation (PD) and resilient modulus (RM). Repeated load triaxial tests, along with X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), were conducted to assess the soil’s mechanical response and microscopic structure. The results indicated that the high concentration of iron oxides contributed to increased cohesion and mechanical strength. When compacted at intermediate Proctor energy, the Purple Clay exhibited RM values comparable to some granular materials reported in the literature, highlighting its potential for pavement applications. However, under higher stress levels, PD was up to 42% greater than that of reference materials, emphasizing the influence of loading conditions on its behavior.

Mussel-Inspired MXene/Antimicrobial Peptide-Integrated Photosensitive Poly(vinyl alcohol)-Based Hydrogel with Antibacterial, Anti-Inflammatory, and Electroactive Properties for Accelerated Wound Healing.

Backgrounds: The buildup of reactive oxygen species (ROS) in infected wounds triggers an excessive inflammatory response, while the overuse of antibiotics has contributed to increased bacterial resistance. Therefore, developing wound dressings that effectively eliminate ROS and inhibit bacterial growth is crucial. Methods: Inspired by mussel-derived proteins, we developed a polydopamine (PDA)-grafted MXene (PDA@MXene) and 3,4-dihydroxyphenylalanine-PonG1 (DOPA-PonG1)-modified photosensitive poly(vinyl alcohol) (PVA) hydrogel as a wound dressing. PDA@MXene was synthesized through dopamine self-polymerization on the MXene surface, while tyrosine hydroxylation was used to introduce DOPA into the antibacterial peptide ponericin G1 (PonG1). The hydrogel and its components were characterized, and their morphology was examined. The hydrogel's hemostatic ability, mechanical properties, and conductivity were evaluated. In vitro studies systematically evaluated antioxidative effects, antibacterial activity, biocompatibility, and expression of tissue regeneration-related factors. An infected full-thickness skin defect model was established in vivo, and different hydrogel treatments were applied. The wound-healing rate was then measured, followed by histological analysis using hematoxylin and eosin, Masson, Sirius Red, and immunofluorescence staining to investigate the healing mechanism. Results: The DOPA sequence enhanced PonG1 stability on the hydrogel surface, leading to sustained antibacterial ability. PDA@MXene significantly improved the hydrogel's conductivity and mechanical strength. Notably, the combined effects of DOPA-PonG1 and PDA@MXene contributed to enhanced antibacterial and ROS-scavenging properties. In vivo findings demonstrated that the DOPA-PonG1/PDA@MXene/PVA hydrogel accelerated infected wound healing by promoting angiogenesis and collagen deposition while reducing excessive inflammation. This study presents an innovative approach for treating infected wound defects and holds promise for clinical applications.

Core-Shell Structured Composite Solid Electrolyte Enables High-Rate All-Solid-State Sodium Batteries.

All-solid-state sodium batteries (ASSSBs) have emerged as the promising candidates for large-scale energy storage; however, they still face challenges related to ionic transport across multi-scale interfaces, which leads to suboptimal battery performances. In this study, we propose a core-shell structured composite electrolyte with Na3PS4 sulfide solid electrolyte (SE) as the core and Na2.25Y0.25Zr0.75Cl6 halide SE as the shell. This design strategy boosts high SE's oxidative stability (4.0 V), ionic conductivity (0.44 mS cm-1) and mechanical strength (Young's modulus of 9.19 GPa). These properties enable the composite SE to effectively mitigate the chemo-mechanically-induced multi-interfacial contact losses at the cathode side. Additionally, the homogeneous full-cell configuration, utilizing the core-shell structured composite electrolyte as both catholyte and SE layer, demonstrates superior rate capability, achieving a discharge capacity of 76.4 mAh g⁻¹ at 2.0 C, significantly outperforming the conventional sandwich-like designs. This work not only provides a novel design strategy for functional SE, but also offers valuable insights into the chemo-mechanical failure mechanism at multiscale interfaces of ASSSBs.

A prediction model of pediatric bone density from plain spine radiographs using deep learning

Osteoporosis, a bone disease characterized by decreased bone mineral density (BMD) resulting in decreased mechanical strength and an increased fracture risk, remains poorly understood in children. Herein, we developed/validated a deep learning-based model to predict pediatric BMD using plain spine radiographs. Using a two-stage model, Yolov8 was applied for vertebral body detection to predict BMD values using a regression model based on ResNet-18, from which a low-BMD group was classified based on Z-scores of predicted BMD. Patients aged 10–20-years who underwent dual-energy X-ray absorptiometry and radiography within 6 months at our hospital were enrolled. Ultimately, 601 patients (mean age, 14 years 4 months [SD 2 years]; 276 males) were included. The model achieved robust performance in detecting vertebral bodies (average precision [AP] 50 = 0.97, AP [50:95] = 0.68) and predicting BMD, with significant correlation (r = 0.72), showing consistency across different vertebral segments and agreement (intraclass correlation coefficient: 0.64). Moreover, it successfully classified low-BMD groups (area under the receiver operating characteristic curve = 0.85) with high sensitivity (0.76) and specificity (0.87). This deep-learning approach shows promise for BMD prediction and classification, with potential to enhance early detection and streamline bone health management in high-risk pediatric populations.

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A well‐controlled segment structure is essential for achieving high‐performance copolymers. A series of block type cyclic olefin copolymers which are composed of both high glass transition temperature, rigid segment and low glass transition temperature, soft segment, and feature high mechanical strength and heat resistance, excellent transparency, and remarkable toughness were developed. These materials were successfully employed in modification of different polyethylenes. More details are discussed in the article by Huang et al. on pages 983—994. image

Tuning the Hydrophobicity of Laser-Annealed rGO Thin Films Synthesized by Pulsed Laser Deposition.

Reduced graphene oxide (rGO) has captivated the scientific community due to its exceptional electrical conductivity, high specific surface area, and excellent mechanical strength. The physical properties of reduced graphene oxide (rGO) are strongly dependent on the presence of different functional groups in its structural framework, along with surface roughness. In this study, laser annealing was employed by a nanosecond Nd:YAG laser to investigate the impact of varying laser energies on the wettability and conductivity of reduced graphene oxide (rGO) samples grown by the pulsed laser deposition (PLD) technique. The rGO films were annealed with different laser fluences, such as 10, 20, 30, 38, 48, 55, and 250 mJ/cm2. Our results reveal a notable transition in wettability, transforming the initially hydrophobic rGO samples into a hydrophilic state. Hydrophilic graphene oxide (GO) or reduced graphene oxide (rGO) surfaces have significant potential for use in biomedical applications due to their unique combination of properties, including biocompatibility, high surface area, and abundant oxygen-containing functional groups. Along with wettability properties, conductivity changes were also observed. The presented findings not only contribute to the understanding of laser-induced modifications in rGO but also highlight the potential applications of controlled laser annealing in tailoring the surface properties of graphene-based materials for diverse technological advancements.

Investigation of Diffusion of Different Composite Materials on the Damage Caused by Axial Impact Adhesive Joints

In this study, the effects of exposure to seawater on the material properties of glass fiber-reinforced polymer (GFRP) and carbon fiber-reinforced polymer (CFRP) samples were investigated. The samples were stored in seawater with a salinity of 3.3–3.7% and a temperature of 23.5 °C taken from the Aegean Sea in September for different periods (1, 2, 3, 6 and 15 months). The samples prepared in accordance with the ASTM D5868-01 standard were subjected to axial impact testing. In the first stage of this study, moisture retention percentages were determined, and, then, axial impact tests were performed. In the tests, a total of 36 samples bonded with single-lap adhesive were subjected to 30 Joule impact energy, and their mechanical strength was evaluated. In line with the experimental results, moisture absorption and axial impact energy values were compared in order to determine the most durable composite material connection, and the most durable connection was selected by evaluating the mechanical properties. Damage analysis on the samples was performed at the DEU Science and Technology Application and Research Center with ZEISS GEMINI SEM 560. (Oberkochen, Germany). The fracture surfaces of the CFRP and GFRP samples after gold coating were examined in detail with a scanning electron microscope, and their interface properties and internal structures were observed. The fracture toughness of GFRP specimens increased from 4.6% in a dry environment to 27.96% after 15 months in seawater. CFRP specimens increased from 4.2% in a dry environment to 11.96% after 15 months in seawater, but the increase was less pronounced compared to GFRP. According to the experimental results, CFRP samples exhibited superior mechanical performance compared to GFRP samples.

Biomechanical Insights into the Development and Optimization of Small-Diameter Vascular Grafts.

Biomechanical Insights into the Development and Optimization of Small-Diameter Vascular Grafts.

An examination of the impact of waste plastic fibers and nanomaterials on concrete properties

Rising construction activity is a major driver of have led to a significant environmental pollution due to the CO2 emission from the cement sector. This study addressed the issue by incorporating of waste plastic fibers at 0%, 1%, 2%, 3%, and 4% by weight of cement, combined with 2.5% nano titanium dioxide (TiO2). The main objective of this study was to assess how these plastic fibers influence the mechanical and fresh properties of concrete. Investigation focused on various concrete properties, including water absorption, mechanical strength such as compressive strength, split tensile strength, and flexural strength, as well as non-destructive testing methods such as Rebound hammer test. High magnification scanning electron microscopy (SEM) images were used to analyze the surface morphology of the concrete micro structure samples after 28 days of curing with different fiber percentages. The study revealed that the compressive strength did not show a significant increase. However, the flexural strength improved by approximately 32.7%, and the split tensile strength increased by about 16.88% with the addition of 2.5% nano TiO2 and 2% waste plastic fibers.

Hemoglobin‐Mediated Dual‐Crosslinked Silk Fibroin With Enhanced Elasticity, Rigidity, Toughness, and Shapeability for Tracheal Tissue Application

AbstractThe study presents an elastic, rigid, and shapeable silk fibroin (SF)‐based scaffold with a dual‐crosslinked network for tracheal tissue engineering. Hemoglobin (Hb), a biocompatible and cost‐effective natural protein, is introduced as both a catalyst and a crosslinker. The in situ chemical crosslinking occurred via a dityrosine reaction in the presence of hydrogen peroxide. Subsequently, freeze‐drying induced the formation of β‐sheet crystals, further physically crosslinking the SF chains, resulting in a 3D porous Hb‐SF scaffold. Additionally, the α‐helix subunits in Hb acted as “molecular springs”, enhancing the scaffold's mechanical strength, elasticity, and toughness. The biomechanical properties of the Hb‐SF scaffold are tunable by adjusting the SF content, enabling precise shape fidelity, self‐recovery, and durability. Notably, the Hb‐SF scaffold exhibited high fatigue resistance, enduring multiple compressive cycles without damage. In vitro tests confirmed its cytocompatibility and potential for cartilage regeneration. Furthermore, in vivo implantation of chondrocyte‐seeded scaffolds resulted in a biomimetic trachea with structural and mechanical properties closely resembling those of the native trachea. This Hb‐mediated, dual‐crosslinked SF scaffold demonstrates enhanced elasticity, rigidity, toughness, and shapeability, presenting a viable option for tracheal tissue regeneration applications.