Robust Structure Research Articles

Electron-Donating Zr Induces Suppressed Ru Over-Oxidation and Accelerated Deprotonation Process Toward Efficient and Durable Water Electrolysis.

The scarcity of cost-effective and durable iridium-free anode electrocatalysts for the oxygen evolution reaction (OER) poses a significant challenge to the widespread application of the proton exchange membrane water electrolyzer (PEMWE). To address the electrochemical oxidation and dissolution issues of Ru-based electrocatalysts, an electron-donating modification strategy is developed to stabilize WRuOx under harsh oxidative conditions. The optimized catalyst with a low Zirconium doping (Zr, 1 wt.%) enhances durability noticeably, with a 77% reduction in degradation rate in the durability test of 10 mA cm-2 in 0.5 m H2SO4. When integrated into a homemade PEMWE device, the Zr-doped catalyst achievesexcellent long-term stability, lasting up to 650 h at 100 mA cm⁻2. Additionally, the electronic modulation from the Zr modification leads to superior activity with a low overpotential of 208 mV at 10 mA cm-2. Theoretical calculation results further reveal that electron-donating Zr modification effectively suppresses Ru overoxidation and lattice oxygen participation, maintaining a robust structure during acidic OER. This modification also promotes deprotonation through stronger Brønsted acid sites, significantly improving both long-term stability and activity.

Hierarchical Selenium-Doped Nickel-Cobalt Hybrids on Carbon Paper for the Overall Water-Splitting Electrocatalytic System.

Designing and constructing hierarchically structured materials with heterogeneous compositions is the key to developing an effective catalyst for overall water-splitting applications. Herein, we report the fabrication of hollow-structured selenium-doped nickel-cobalt hybrids on carbon paper as a self-supported electrode (denoted as Se-Ni|Co/CP, where Ni|Co hybrids consist of nickel-cobalt alloy-incorporated nickel-cobalt oxide). The procedure involves direct growth of zeolitic imidazolate framework-67 (ZIF-67) on bimetal-based nickel-cobalt hydroxide (NiCoOH) electrodeposited on CP, followed by selenous etching and pyrolysis to obtain the final Se-Ni|Co/CP electrocatalytic system. The optimized Se-Ni|Co/CP [Se-Ni1|Co9/CP(0.3)] exhibits remarkable performance in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), displaying a current density of 10 mA cm-2 at small overpotentials of 105 mV for HER and 235 mV for OER. Furthermore, it allows an alkali electrolyzer to achieve a current density of 10 mA cm-2 at a cell voltage of only 1.51 V. The outstanding catalytic activity of Se-Ni|Co/CP is ascribed to the high intrinsic activity of the bimetallic catalyst, efficient interfaces, and charge transport facilitated by the heterogeneous component, the hollow structure inherited from the metal-organic frameworks (MOF)-derived material providing ample porosity and active sites, and structural robustness achieved through self-supported construction.

Beyond Inducing Anionic Redox: Controllable Migration Sequence of Li Ions in Transition Metal Layers Toward Highly Stable Li-Rich Cathodes.

The energy density of layered oxides of Li-ion batteries can be enhanced by inducing oxygen redox through replacing transition metal (TM) ions with Li ions in the TM layer. Undesirably, the cathodes always suffer from unfavorable structural degradation, which is closely associated with irreversible TM migration and slab gliding, resulting in continuous capacity and voltage decay. Herein, attention is paid to the Li ions in the TM layer (LiTM) and find their extra effects beyond inducing oxygen redox, which has been rarely mentioned. With the aid of 7Li solid-state NMR and density functional theory (DFT) calculations, the controllable migration of LiTM is verified. The mystery is uncovered that the preferential migration of LiTM plays an imperative role in preventing the structural transformation by postponing the slab gliding of the layered structure. Integrated with the inhibited TM migration, the structural robustness and reversibility of Li2RuO3 can be drastically improved after Zr-substitution, providing a solid foundation for achieving ultra-stable electrochemical performance even after thousands of cycles (2500 cycles). The discovery highlights the significance of LiTM with respect to the structural robustness and provides a potential route toward high-energy-density Li-ion batteries.

A Simple Machine Learning-Based Quantitative Structure–Activity Relationship Model for Predicting pIC50 Inhibition Values of FLT3 Tyrosine Kinase

Background/Objectives: Acute myeloid leukemia (AML) presents significant therapeutic challenges, particularly in cases driven by mutations in the FLT3 tyrosine kinase. This study aimed to develop a robust and user-friendly machine learning-based quantitative structure–activity relationship (QSAR) model to predict the inhibitory potency (pIC50 values) of FLT3 inhibitors, addressing the limitations of previous models in dataset size, diversity, and predictive accuracy. Methods: Using a dataset which was 14 times larger than those employed in prior studies (1350 compounds with 1269 molecular descriptors), we trained a random forest regressor, chosen due to its superior predictive performance and resistance to overfitting. Rigorous internal validation via leave-one-out and 10-fold cross-validation yielded Q2 values of 0.926 and 0.922, respectively, while external validation on 270 independent compounds resulted in an R2 value of 0.941 with a standard deviation of 0.237. Results: Key molecular descriptors influencing the inhibitor potency were identified, thereby improving the interpretability of structural requirements. Additionally, a user-friendly computational tool was developed to enable rapid prediction of pIC50 values and facilitate ligand-based virtual screening, leading to the identification of promising FLT3 inhibitors. Conclusions: These results represent a significant advancement in the field of FLT3 inhibitor discovery, offering a reliable, practical, and efficient approach for early-stage drug development, potentially accelerating the creation of targeted therapies for AML.

Why is learning from patient safetyincidents (still) so hard? Asociocultural perspective onlearningfrom incidents inhealthcare organizations.

Despite robust quality improvement efforts in healthcare, learning from patient safety incidents remains difficult. Our study explores counter-vailing powers shaping learning processes and possibilities in healthcare organizations, with a focus on social, political and organizational dynamics of learning. Deploying concepts of situated curriculum, boundary work and interconnected knowledge practices, we interviewed staff and physicians (n=15) in a large Academic Health Science Centre in Canada about their experiences of incident investigations and resultant information sharing. Our analytical strategy was abductive, drawing connections to sociology of the professions and learning sciences literature. Incident investigation and follow-up processes are relatively robust for learning about incidents in the organization. However, learning from incidents remains difficult, complicated by the professional politics of incident classification, counter-vailing policies related to privacy, the organization of improvement work towards reporting, and an organizational focus on incidents with severe outcomes. Participants advocated for a broader view of incidents, moving beyond classification and investigation based on severity of outcome to also include incidents that are "learning rich". To that end, we argue for more research on the role of Patient Safety Specialists in organizational learning and more collaborations with learning sciences. This paper illuminates ways in which robust information dissemination structures are an important but insufficient condition for learning from incidents. The argument goes beyond a prescriptive approach to learning from incidents to instead explore the competing visions and values implicated with improvement practices.

Bioprospecting of a Native Plant Growth-Promoting Bacterium Bacillus cereus B6 for Enhancing Uranium Accumulation by Sudan Grass (Sorghum sudanense (Piper) Stapf)

Phytoremediation technology is viewed as a potential solution for addressing soil uranium contamination. Sudan grass (Sorghum sudanense (Piper) Stapf.), noted for its robust root structure and resilience to heavy metals, has garnered significant attention. This paper investigates a strain of uranium-tolerant bacterium, B6, obtained from the inter-root environment of native plants in soil contaminated with uranium tailings. The bacterium was identified as Bacillus cereus. Genomic analyses and assessment of uranium tolerance-promoting properties showed that strain B6 not only exhibited high uranium tolerance, but also possessed beneficial properties such as phosphorus solubilization and iron-producing carriers. In this study, we used strain B6 as an inoculant in combination with Sudan grass for germination and potting experiments. The findings demonstrated that Bacillus cereus B6 could substantially mitigate the adverse effects of uranium stress on Sudan grass, boost the plant’s antioxidant response, significantly increase the root length and dry biomass of Sudan grass, and facilitate the accumulation of uranium in the roots, as well as its translocation to the aboveground portions. The study showed that PGPB strain B6 can significantly enhance the effect of plant accumulation of uranium and increase the potential of Sudan grass to become a uranium-rich plant, which provides an important scientific basis and application prospect for the use of microbial-assisted Sudan grass remediation technology to treat uranium-contaminated soil.

Rapid Room Temperature Entropy‐Stabilized Synthesis Enabling Super‐Stable Metal Halide Perovskite Semiconductor Colloidal Nanocrystals

AbstractAlthough high‐entropy materials have garnered extensive attention due to their substantially enhanced performance, their formation generally demands prolonged high‐temperature synthetic processes. Moreover, research on entropy‐stabilized halide perovskite (ESHP) semiconductor colloidal nanocrystals (NCs) is scarce. Herein, a highly efficient and rapid room temperature (RT) entropy‐stabilized approach in air is proposed, involving the concurrent incorporation of multi‐metal cations for the synthesis of high‐quality all‐inorganic ESHP NCs with near‐unity quantum yield and excellent colloidal stability. Remarkably, even after 8 months of aging in air, the ESHP NCs exhibited superior emission characteristics with a single‐exponential decay and maintained the initial NC monodispersity. Density functional theory calculations further demonstrated that the outstanding performance of ESHP NCs originated from the diminished crystal defects and a more robust octahedral structure. Significantly, this RT entropy‐driven synthesis can be extended to metal halide semiconductor NCs with diverse composition systems. The findings inspire new perspectives for entropy‐stabilized, high‐performance metal halide perovskite NCs toward versatile applications.

Wind-induced structural behavior and optical performance of a lightweight composite-based paraboloidal solar dish

Among the four available concentrating solar-thermal (CST) power systems, parabolic dish systems show great potential as the preferred technology for renewable electricity generation. Nonetheless, the weight of the support structure poses a major hurdle to its development. As of present, solar dishes utilize steel structures to hold the reflective panels which amount to a lot of weight, necessitating large and expensive drive units and increases energy consumption. Hence, for the dishes to advance and further become economically feasible in the near future, the structures found need to be replaced with cost-effective materials that not only diminish the weight but still maintain the structural integrity found with the steel. Hence, this investigation embodies the first effort in literature to explore the viability of utilizing honeycomb sandwich composites as a lightweight and robust support structure for solar dishes, with the ability to cope with the aerodynamic loads imposed upon them during operation. Through combined fluid-structure interaction (FSI) and ray tracing analysis, the wind-induced structural behavior and optical performance of the sandwich composite-based paraboloidal solar dish were investigated under various loading scenarios at various azimuth and elevation angles. Under dissimilar operational conditions, the proposed system exhibited varying behavior characteristics, with the worst conditions being assessed according to relevant material failure and optical standards. With the worst operational condition taking place at 0° azimuth and 30° elevation, the detailed FSI-ray tracing analysis demonstrated that the dish managed to satisfy the set specifications, highlighting the potential and effectiveness of using honeycomb sandwich composites as a support structure for parabolic dish systems.

Stereoactive Lone-Pair Manipulation for High Thermoelectric Performance of GeSe-Based Compounds.

Materials with high crystallographic symmetry are supposed to be good thermoelectrics because they have high valley degeneracy (NV) and superb carrier mobility (μ). Binary GeSe crystallizes in a low-symmetry orthorhombic structure accompanying the stereoactive 4s lone pairs of Ge. Herein, we rationally modify GeSe into a high-symmetry rhombohedral structure by alloying with GeTe based on the valence-shell electron-pair repulsion theory. We demonstrate that the substitution of Se by Te weakens the stereoactivity of the Ge lone-pair electrons, resulting in robust rhombohedral structures of GeSe1-xTex for x ≥ 0.3 at room temperature. The increase of crystal symmetry not only boosts NV from 2 for orthorhombic GeSe to 9 for rhombohedral GeSe1-xTex but greatly enhances μ from <5 to >10 cm2 V-1 s-1 (room-temperature values), thereby remarkably elevating the power factors by 2 orders of magnitude (26.9 μW cm-1 K-2 at 638 K for x = 0.5). Surprisingly, despite their higher crystallographic symmetry, rhombohedral GeSe1-xTex compounds display even lower lattice thermal conductivities (∼1.0 W m-1 K-1 at 300 K for x = 0.5) than binary GeSe (∼2.5 W m-1 K-1 at 300 K) due to abundant alloying defects in the Se-Te sublattice and ferroelectric instability. Altogether, a maximum ZT value of ∼1.1 at 638 K is achieved in rhombohedral GeSe0.5Te0.5, which already outperforms GeTe. This work provides an avenue for engineering the thermoelectric properties of low-symmetry compounds containing lone-pair electrons.

Five-Axis Printing of Continuous Fibers on the Mold

This paper explores a five-axis printing method designed to improve the fabrication of continuous fiber-reinforced thermoplastic composites (CFRTPCs), essential for producing lightweight, complex structures in advanced manufacturing. Traditional CFRTPC placement techniques often face challenges with precision, scalability, and optimal fiber orientation, especially in customized, small-scale applications. The proposed five-axis printing technique overcomes these issues by enabling precise fiber orientation and the production of robust spatial structures using 3D-printed molds compatible with CFRTPCs. Validation through three-point bending and surface quality tests revealed that five-axis printed cylindrical-lattice samples, with fibers oriented at 45°, exhibited superior mechanical properties and surface quality. The five-axis printed samples achieved a load-to-weight ratio 27% higher than traditional samples and maintained their shape even under significant deformation. Surface quality improved significantly, with roughness values reduced from 37.63 µm to approximately 12 µm. This method advances CFRTPC applications in industries requiring complex, lightweight components.

Engineering Management and Modular Design: A Path to Robust Manufacturing Processes

Manufacturing environments, characterized by dynamic changes and uncertainties, demand effective strategies to minimize disruptions. This study introduces an innovative approach that integrates engineering management principles with modular design to prioritize risk mitigation and enhance robustness in manufacturing processes. From a systems engineering perspective, all manufacturing activities are perceived as interconnected components within a unified system. Leveraging the Axiomatic Design (AD) theory and the Design Structure Matrix (DSM) method, the study modularizes manufacturing process architecture to effectively curb risk propagation and manage system complexity. This study identifies the most optimal design as a pivotal architectural configuration, significantly improving the structural robustness and stability of the System of Interest (SOI). Empirical evidence supports this design’s capability to reduce complexities, thereby enhancing robustness within the broader system architecture. Notably, the proposed approach results in a substantial reduction in complexity, with the most optimal design exhibiting an approximately 82.79 percent reduction in work volume compared to the original design. Our research underscores the critical relationship between manufacturing and engineering management. Effective collaboration between these domains optimizes resource allocation, decision-making processes, and overall organizational strategy, leading to improved production processes and increased efficiency. Importantly, the study demonstrates a significant enhancement in modularization, resulting in elevated overall robustness in manufacturing processes. This highlights the proactive involvement of engineering management in the design phase to address production challenges, ultimately optimizing system performance. Thus, this research contributes to both practical applications and academic discourse by offering a novel approach to enhancing the robustness in manufacturing processes. By integrating engineering management principles and modular design strategies, organizations can fortify their processes against disruptions and effectively adapt to evolving circumstances.

Confining CoSe/MoSe2 Heterostructures in Interconnected Carbon Polyhedrons for Superior Potassium Storage.

Metal selenides hold promise as feasible anode materials for potassium-ion batteries (PIBs), but still face problems such as poor potassium storage kinetics and dramatic volume expansion. Coupling heterostructure engineering with structural design could be an effective strategy for rapid and stable K+ storage. Herein, CoSe/MoSe2 heterojunction encapsulated in nitrogen-doped carbon polyhedron and further interconnected by three-dimensional nitrogen-doped carbon nanofibers (CoMoSe@NCP/NCFs) is ingeniously constructed. The abundant CoSe/MoSe2 heterointerfaces equipped with built-in electric fields and unique interconnected carbon polyhedrons (convenient electron/ion transfer pathway and robust mechanical buffer) promote the reaction kinetics and bolster the structural robustness. Accordingly, the CoMoSe@NCP/NCFs composite exhibits outstanding cycle life, with a capacity of 206 mAh g-1 preserved after 2500 cycles at 2 A g-1. Besides, CoMoSe@NCP/NCFs also achieves decent rate performance with 161 mAh g-1 at 10 A g-1. This research demonstrates a viable approach for constructing superior PIB anodes with both fast kinetics and high stability.

Ultrafast, Robust, and Reversible Self-Assembled Nanofibers via Thiolactone Chemistry Strategy.

Self-assembly in supramolecular chemistry is crucial for nanostructure creation but faces challenges like slow speeds and lack of reversibility. In this study, a novel comb-like polymer poly(amide sulfide) (PAS) based on thiolactone chemistry is reported, which rapidly self-assemble into stable nanofibers, offering excellent robustness and reversibility in the self-assembled structure. The PAS backbone contains pairs of amide bonds, each linked to an alkyl side chain in a controlled 2:1 ratio. The polymer rapidly forms fibrillar micelles driven by the hydrophobic side chains and then undergoes hydrogen-bonded cross-linking between the main-chain amide bonds to form stable nanofibers. N, N-dimethylacetamide/LiCl solution allows for reversible regulation of nanofiber self-assembly, without altering the fiber properties. It is anticipated that this line of research will enrich the field of macromolecular self-assembly with important advances toward the realization of ultrafast, robust, and reversible self-assembly systems.

Robust RNA secondary structure prediction with a mixture of deep learning and physics-based experts.

A mixture-of-experts (MoE) approach has been developed to mitigate the poor out-of-distribution (OOD) generalization of deep learning (DL) models for single-sequence-based prediction of RNA secondary structure. The main idea behind this approach is to use DL models for in-distribution (ID) test sequences to leverage their superior ID performances, while relying on physics-based models for OOD sequences to ensure robust predictions. One key ingredient of the pipeline, named MoEFold2D, is automated ID/OOD detection via consensus analysis of an ensemble of DL model predictions without requiring access to training data during inference. Specifically, motivated by the clustered distribution of known RNA structures, a collection of distinct DL models is trained by iteratively leaving one cluster out. Each DL model hence serves as an expert on all but one cluster in the training data. Consequently, for an ID sequence, all but one DL model makes accurate predictions consistent with one another, while an OOD sequence yields highly inconsistent predictions among all DL models. Through consensus analysis of DL predictions, test sequences are categorized as ID or OOD. ID sequences are subsequently predicted by averaging the DL models in consensus, and OOD sequences are predicted using physics-based models. Instead of remediating generalization gaps with alternative approaches such as transfer learning and sequence alignment, MoEFold2D circumvents unpredictable ID-OOD gaps and combines the strengths of DL and physics-based models to achieve accurate ID and robust OOD predictions.

Rapid Crystallization and Versatile Metalation of Acetylhydrazone-Linked Covalent Organic Frameworks for Heterogenous Catalysis.

Covalent organic frameworks (COFs) hold promise in heterogeneous metal catalysis benefiting from their robust, crystalline, and porous structures. However, synthetic challenges persist in prolonged crystallization times, limited metal loading, and uncertain coordination environments. Here, we present the rapid crystallization and versatile metalation of new acetylhydrazone-linked COFs (AH-COFs) by condensation of ketone and hydrazide components, featuring full conversion within 30 min under open-air and mild conditions. The obtained AH-COFs exhibit exceptional thermal and chemical stability, maintaining high crystallinity and microporosity even under harsh conditions. This method shows the versatility of in situ metalation through subcomponent assembly with a wide range of metal centers, and the delicate control of coordination geometry through isoreticular functionalization for fine-tuning of the pore environments and metal catalytic activity. The metalated AH-COFs demonstrate excellent catalytic performance: AH-COF-2-Zn achieves high efficiency in CO2 cycloaddition, while AH-COF-1-Cu-PSM achieves near-quantitative conversion in copper-catalyzed azide-alkyne cycloaddition (CuAAC) reactions, with both catalysts retaining their activity over multiple cycles. This study offers an efficient and versatile method for the rapid crystallization of designable, stable, and functional COFs, heading to practical applications prioritized on efficiency, scalability, and sustainability.

Designed construction of two new atom-precise three-dimensional and two-dimensional Ag12 cluster-assembled materials.

Silver cluster-assembled materials (SCAMs) are well-defined crystalline extended materials hallmarked by their unique geometric structures, atomically precise designability and functional modularity. In this study, we report for the first time the synthesis of a (3,6)-connected three-dimensional (3D) SCAM, [Ag12(StBu)6(CF3COO)6(TPMA)6]n (designated as TUS 6), TPMA = tris(pyridine-4-ylmethyl)amine, by assembling Ag12 cluster nodes with the help of a tritopic linker TPMA. Besides, we also prepared a two-dimensional (2D) SCAM, [Ag12(StBu)6(CF3COO)6(TPEB)6]n (described as TUS 7), TPEB = 1,3,5-tris(pyridine-4-ylethynyl)benzene, by reticulating Ag12 nodes with a tritopic linker TPEB. Characterized by microscopic and diffraction analyses, the SCAMs revealed distinct morphologies, structural robustness, and phase purity. This paper elucidates how the binding with the organic linkers alters the symmetry of the silver nanoclusters (NCs). Changes in the symmetry of discrete NCs to assembled structures have not been reported yet. This study provides an atomic-level explanation of the transformation of symmetry from NCs to extended structures.

Changes in rheological properties and structure of wheat gluten proteins induced by transglutaminase.

To elucidate the effect of transglutaminase (TG) on the rheological properties of wheat gluten, this study investigates the underlying mechanisms by analyzing changes in gluten structure. The results demonstrated that the TG-treated gluten samples had higher storage modulus (G') and loss modulus (G″) compared to the control, conversely, creep and recovery strains followed an opposite trend. Notably, the most pronounced effects were observed with adding 2U/g TG for 20-30min. Size exclusion/reversed phase-high performance liquid chromatography profiles revealed that the treatment with TG elevated the levels of glutenin subunits, alongside reduced α- and γ-gliadins, promoting gluten aggregation. Moreover, the extractability of gluten gradually decreased due to TG-induced oxidation of sulfhydryl groups, which formed new disulfide bonds and cross-linked products. This structural modification reduced surface hydrophobic regions and promoted the aggregation of low molecular weight proteins into larger molecular weight aggregates. Microstructural analysis further confirmed that TG enhanced gluten network stability through covalent cross-linking. Overall, this study demonstrates that TG enhances the rheological characteristics of wheat gluten by facilitating the formation of a more robust network structure, driven by cross-linking reactions and disulfide bond formation.

Gastrointestinal pH-sensitive Pickering emulsions stabilized by glycosylated zein conjugates ferulic acid nanoparticles: Improving oral bioaccessibility of Coenzyme Q10.

Pickering emulsion stabilized by food grade nanoparticles with stimulus response as a targeted delivery system for lipophilic bioactive compounds has attracted people's attention. In this study, ferulic acid was used to modify saccharified zein to prepare pH-sensitive nanoparticles for stabilizing Pickering emulsion. The structure, interface behavior, stability of Pickering emulsion and gastrointestinal digestion characteristics of nanoparticles in vitro were studied. The results showed that covalent embedding of ferulic acid (ZGF-con) effectively improved the surface properties of zein nanoparticles based on glycosylation modification of zein, further regulating their behavior at the oil-water interface. In addition, the particle size of ZGF-con was small (92.93 nm), the wettability was moderate (89.85 °), and it was spherical, with orderly transition of secondary structure, which was conducive to the formation of stable emulsion at the oil-water interface. The stable Pickering emulsion formed by ZGF-con showed ideal emulsification performance, and the electrostatic repulsion between droplets and the formation of a robust spatial network structure promoted the stability of the emulsion. In addition, the encapsulation efficiency of CoQ10 in ZGF-con stabilized Pickering emulsion reached 96.11 %. In vitro simulated digestion, ZGF-con stabilized Pickering emulsion was relatively stable in the gastric acid environment, and slowly released in the small intestine, realizing the small intestine targeted release of CoQ10, which increased its bioaccessibility from 10.57 % to 56.42 %. This study provides an effective strategy for the preparation of pH-sensitive Pickering emulsion to improve the bioaccessibility of hydrophobic active ingredients.

Soil-aggregate-cement mixtures for base pavement layers: A strength and stiffness characterization

Pavements subjected to high volume load require a robust structure. In Brazil, cemented base layer is usually used instead of asphalt concrete thick layer due to cost issues. Soil-aggregate-cement (SAC) mixture is an alternative in pavement application, but the lack of design and dosage protocols hinders the understanding of the parameters influencing its mechanical behavior. This study presents a mechanical characterization of SAC mixtures in terms of strength (UCS and ITS) and stiffness (Mr), focusing on integrating the needs of pavement design to dosage purposes. For this, different SAC mixtures are produced, varying the soil-aggregate proportion (30:70 and 20:80) and cement content (3, 5 and 7 %). Mechanical properties were measured on cured mixtures at 0, 7 and 28 days and compared to structural responses of hypothetical pavements computed by mechanistic analysis. The results indicate a potential for using SAC mixtures in base layers due to their higher strength and stiffness. Predictive models relating ITS x UCS, Mr x UCS, and Mr x ITS with good statistical fit were proposed to assist researchers and engineers in selecting mixtures more adequate and durable for pavement applications, based on the concept of limiting the tensile stress acting on the cemented base course.

Penguin feather-inspired flexible aerogel composite films featuring ultra-low thermal conductivity and dielectric constant.

Given extremely high porosity, aerogels have demonstrated remarkable advantages in serving as thermal insulation and wave-transparent materials. Unfortunately, their practical applications are greatly confined by their inherent fragility. The recent emergence of polymer aerogels presents an ideal platform for the development of flexible aerogel films. However, additional cross-linking agents are necessitated for constructing a robust structure, complicating the production process. Herein, we report a flexible aerogel film based on meta-aramid composites, inspired by the porous structure of penguin feathers. The intermolecular hydrogen bonds function as natural cross-linking agents. Their disruption results in the dissolution of meta-aramid fibers, while their reconstruction facilitates localized rearrangement of meta-aramid chains during the sol-gel process, generating closed nanopores. Furthermore, fluorinated hollow glass microspheres are filled, compressing the nanopores situated near the interface to 75-150 nm. This meets the critical threshold required by the Knudsen effect, decreasing the thermal conductivity to levels below that of ambient air. At an optimized doping ratio of 3 wt%, the thermal conductivity is 21.6 mW m-1 K-1, while achieving a low dielectric constant of 1.43. Simultaneously, aerogel films exhibit enhanced mechanical properties, and also show benefits of hydrophobicity, colorability, ultralightness, and flame retardancy, making themselves multifunctional materials suitable for practical applications.