Search Results (734)

This study systematically investigated the effects of carbon fiber (CF) content (0%, 0.15%, 0.3%) and strain rate (10⁻⁵/s, 10⁻⁴/s, 10⁻³/s, 10⁻²/s) on the mechanical properties, microstructure, and microscopic damage evolution of carbon fiber-modified recycled concrete (CFRRAC) using uniaxial compression testing, scanning electron microscopy (SEM) observation, acoustic emission (AE), and statistical damage theory. The results indicate that the moderate addition of CF can effectively improve the compactness of the microstructure of the specimen, enhance the strain rate effect of CFRRAC, and improve its initial macroscopic mechanical properties. The microstructure characteristics of specimens with different CF contents and the Stefan effect related to strain rate further affect the initiation and propagation morphology, propagation path, and adjustment process of effective stress skeleton of microcracks during uniaxial compression, leading to regular changes in characteristic parameters characterizing microfracture and yield damage evolution with CF content and strain rate. The above factors collectively determine the evolution characteristics of the macroscopic nonlinear stress–strain behavior of CFRRAC, combined with the CF bridging toughening effect, ultimately resulting in an increase in strength with increasing strain rate and maintaining good ductility. Compared with the specimens without CF doping, the peak stress of CFRRAC increased by 37.16% to 41.18% and the peak strain increased by 22.94% to 36.57% in the strain rate range of 10⁻⁵ to 10⁻²/s at a dosage of 0.3%. Taking the CFRRAC specimen with a content of 0.3% as an example, compared with the strain rate of 10⁻⁵/s, the peak stress of the specimen increased by 9.31%, 18.66%, and 31.24% at strain rates ranging from 10⁻⁴ to 10⁻²/s, respectively. The research results can provide theoretical support for the promotion and application of CFRRAC in the engineering field. Full article

The surface condition of the bond coat is an important factor governing the growth and microstructural development of electron-beam physical vapour deposition (EB-PVD) TBCs. In this study, 7 wt.% yttria-stabilised zirconia (7YSZ) coatings were deposited by EB-PVD on vapour-phase aluminide bond coats with three distinct surface conditions, ranging from the as-coated state to ground and polished surfaces. The effect of bond coat roughness was evaluated through surface profilometry, scanning electron microscopy, X-ray diffraction, quantitative analysis of columnar architecture and porosity, scratch testing, and Vickers microindentation. Reducing the bond coat roughness resulted in a more uniform columnar architecture, reduced intercolumnar spacing, and a lower degree of column inclination, accompanied by a decrease in the coating surface roughness. XRD confirmed the formation of the expected tetragonal/cubic 7YSZ phase assemblage for all investigated conditions. Scratch testing revealed no delamination or spallation up to the maximum applied load of 200 N, indicating high interfacial integrity irrespective of bond coat roughness. Vickers measurements revealed a statistically significant through-thickness hardness gradient for all coatings, with hardness decreasing from the bond coat interface towards the column tips. Importantly, bond coat roughness had no statistically significant effect on hardness near the interface or in the central region, whereas significant differences were observed near the column tips. These results demonstrate that bond coat roughness strongly governs EB-PVD columnar architecture and surface morphology, while its influence on hardness is predominantly confined to the uppermost region of the coating. Full article

Friction stir welding (FSW) is a solid-state joining process widely used for aluminum alloys due to its low heat input, reduced distortion, and ability to produce high-quality joints. However, excessive tool forces generated during the welding process can increase machine loading, accelerate tool wear, and negatively affect the process efficiency. Therefore, understanding the relationship between welding parameters, tool forces, and the joint performance is essential for achieving high-quality welds while avoiding unnecessary mechanical loads. In this study, 4 mm thick AA5754 aluminum alloy plates were joined using the FSW process, and the feasibility of using tool force measurements for process optimization was investigated. A comprehensive experimental matrix consisting of nine different rotational speeds and ten different tool travel speeds was established based on preliminary studies and previous literature. During each welding operation, forces acting on the tool in the F_x, F_y, and F_z directions were continuously recorded. The welded joints were evaluated through tensile testing (Zwick Z300 universal testing machine, ZwickRoell, Ulm, Germany), hardness measurements, and microstructural characterization using scanning electron microscopy (SEM) (ZEISS Merlin scanning electron microscope, Carl Zeiss Microscopy GmbH, Oberkochen, Jena, and Göttingen, Germany). A Pearson correlation analysis and a two-way analysis of variance (ANOVA) were performed at a 95% confidence level to quantify the relationships and statistical significance of the process parameters. The results showed that F_z was the dominant force component during welding. The rotational speed had a statistically significant effect on the tensile strength, yield strength and hardness (p < 0.05), accounting for 99.39% of the total variation in hardness. For the mean tool force, both the rotational speed and the tool travel speed were statistically significant (p < 0.0001), contributing 38.48% and 47.16% of the total variation, respectively. The rotational speed also accounted for 81.55% of the variation in the maximum axial force. The Pearson correlation analysis showed a strong negative correlation between the rotational speed and hardness (r = −0.73), whereas the tool travel speed showed positive correlations with F_x (r = 0.61), F_z (r = 0.62), and the mean tool force (r = 0.68). Despite the increased tool loading associated with higher travel speeds, no corresponding improvement in the mechanical performance was observed. The results demonstrated that appropriately selected welding conditions produced joints with a yield strength and hardness exceeding 90% of the corresponding base material properties while maintaining relatively lower tool forces. SEM observations confirmed grain refinement in the stir zone. Overall, the combined correlation and ANOVA results demonstrate that real-time tool force monitoring can provide a quantitative basis for selecting FSW parameters that achieve an adequate mechanical performance while minimizing unnecessary machine and tool loading. Full article

Although cryptocurrency markets trade continuously, the intraday distribution of Bitcoin’s volatility has migrated toward United States trading hours as the asset has institutionalized. Using ten years of hourly Kraken XBT/USD data (2016–2025; 87,672 observations), I document this migration and tie its timing to the U.S. trading calendar with two natural experiments. When U.S. clocks change, the intraday volatility peak shifts by one hour in UTC, tracking the displaced equity open; the shift appears only in the institutionalized period. On weekday NYSE holidays, when the U.S. cash market is closed while most other markets trade, the U.S.-hours share of realized variance falls by 13.9 percentage points relative to matched weekdays, close to the uniform benchmark of 0.375 (the share expected if variance were distributed evenly across the 24 h day), and this effect is also absent before 2019. Neither result is consistent with an explanation fixed in UTC. A window-free circular index of intraday concentration rises by more than 40% over the decade, with a structural break in November 2021, and no local break at the 2017 futures launch or the 2024 spot-ETF approval. A placebo simulation shows that naive whole-sample event contrasts on this trending series are significant for 100% of random pseudo-event dates. The microstructure of a nominally 24/7 market increasingly bears the imprint of the U.S. equity calendar. Full article

This study systematically investigates the effects of infiltration temperature (800 and 1000 °C) and magnesium (Mg) content (0, 5, and 10 wt.%) on the density, morphology, and chemical composition of silicon carbide/aluminum-magnesium (SiC/Al–Mg) composites. Poor wettability between molten Al and SiC can restrict the infiltration of porous SiC preforms. Although Mg is commonly used to improve wettability, the combined effects of Mg content and infiltration temperature have not been investigated for composites produced from binder-jetted SiC preforms. Porous SiC preforms were first fabricated by binder jetting of SiC powder and then air-assisted oxidation bonded at 1200 °C for 2 h. The oxidation-bonded preforms were subsequently spontaneously melt infiltrated under an inert atmosphere using either pure Al powder or Al–Mg powder mixtures containing 5 or 10 wt.% Mg. The results showed that composite density increased consistently with increasing Mg content. At 800 °C, the density increased from 1.73 to 2.63 g/cm³ as Mg content increased from 0 to 10 wt.%. Similarly, at 1000 °C, the density increased from 1.80 to 2.73 g/cm³. X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to evaluate phase formation and microstructural features. The results confirmed effective infiltration in Mg-containing samples, while samples without Mg showed limited infiltration at both temperatures. A two-way ANOVA showed that Mg content was the primary factor controlling post-infiltration density, while infiltration temperature had a smaller but statistically significant effect. These findings provide practical guidance for selecting Mg content and infiltration temperature during the fabrication of binder-jetted SiC/Al–Mg composites. Overall, this study highlights the importance of Mg-assisted infiltration for fabricating binder-jetted SiC/Al–Mg composites and provides processing insights relevant to their potential use in aerospace, automotive, and defense applications, subject to further evaluation of their mechanical and functional properties. Full article

Background: Cluster headache is a severe primary headache disorder in which neuroimaging studies have suggested involvement of hypothalamic, limbic, and pain-related networks. Although hippocampal abnormalities have been reported in some studies, volumetric findings remain inconsistent and may depend on disease state, treatment exposure, chronicity, and imaging methodology. We explored whole hippocampus and hippocampal subfield volumes in medication-free patients with episodic cluster headache scanned interictally during an active bout. Methods: In this cross-sectional case–control study, 26 patients with episodic cluster headache (eCH) and 20 age- and sex-matched healthy controls underwent 3 T brain MRI. Patients were scanned during an active bout but outside acute headache attacks and had not received preventive treatment for at least three months before MRI acquisition. Automated hippocampus segmentation and subfield volumetry were performed using FreeSurfer 7.4.1, followed by visual quality control by two neuroradiologists. Group comparisons were adjusted for age, sex, and total intracranial volume. Multiple comparisons were addressed using Bonferroni correction for whole hippocampal volumes and false discovery rate (FDR) correction for subfield and clinical analyses. Results: No significant differences were detected between eCH patients and healthy controls in whole hippocampus or hippocampal subfield volumes after correction for multiple comparisons. Descriptive analyses showed numerically higher volumes in patients across several regions, but these effects were small to moderate and did not reach statistical significance. Exploratory analyses showed a nominal association between right fimbria volume and pain intensity; however, this association did not survive FDR correction. Conclusions: This study found no evidence of detectable hippocampal macrostructural differences in medication-free eCH patients scanned interictally during active bouts using 3 T MRI-based subfield volumetry. These null findings should not be interpreted as proof of preserved hippocampal structure, but rather as absence of measurable volumetric alterations within the limits of the present sample size, acquisition protocol, and analytical framework. Longitudinal and multimodal studies, including in-bout and out-of-bout assessments, higher-resolution imaging, and neuropsychological covariates, are needed to clarify whether hippocampal involvement in eCH is structural, microstructural, functional, or state-dependent. Full article

Coral aggregate seawater concrete (CASC) capitalizes on locally sourced aggregates in marine and reef engineering, enabling in situ material utilization and conferring marked benefits in curbing conventional resource consumption and construction expenditures—a combination that underpins its considerable promise for reef infrastructure development. To date, research efforts have largely been confined to macroscopic mechanical characterization and qualitative microstructural inspections, and quantitative assessments of mesoscopic damage evolution across the full loading-to-failure process remain relatively scarce. In response, to quantitatively characterize the mesoscopic damage evolution mechanism of CASC with different natural aggregates, the present study draws upon statistical damage theory and incorporates uniaxial compressive stress–strain responses from CASC mixtures formulated with four replacement ratios (0%, 33%, 67%, and 100%) of natural coarse and fine aggregates, thereby establishing a statistical damage constitutive model. The model is intentionally structured to decipher the intricate interplay that translates progressive mesoscopic deterioration into the eventual macroscopic mechanical signature, rather than merely describing phenomenological curves. The outcomes reveal favorable concordance between model-generated predictions and experimental measurements. Introducing natural aggregates appreciably modulates the cumulative damage trajectory at the mesoscale; with rising replacement ratios, the macroscopic mechanical performance of CASC is systematically fortified, concomitant with orderly shifts in characteristic damage indices (ε_a, ε_b, ε_h and H). Specifically, when the replacement ratio of natural fine aggregate is fixed at 0%, as the replacement ratio of natural coarse aggregate increases from 0% to 100%, the values of ε_a, ε_b, ε_h, and H increase by 35.8%, 36.9%, 32.2%, and 66.5%, respectively. Additionally, both the fracture damage variable D_R and the integrated transverse strain area derived from digital image correlation (DIC) exhibit monotonic ascending trends as loading advances. Collectively, these contributions offer a theoretical foundation for performance optimization and a deeper mechanistic understanding of damage behavior in CASC. Full article

The valorization of industrial textile waste as reinforcement in cementitious materials offers a promising approach for reducing polymer waste while improving the performance of cement-based composites. This study investigates recycled polypropylene (PP) fibers recovered from Moroccan pre-consumer textile waste for application in mortar and concrete. Thirteen fiber types were initially screened based on their geometrical and morphological characteristics, and four representative fibers were selected for detailed characterization and experimental evaluation. Fiber-reinforced mortars were first investigated to assess the influence of fiber type and dosage, followed by concrete-scale evaluation through mechanical, shrinkage, transport-related, and microstructural tests. The results showed that fiber characteristics and dosage influenced composite performance, with the magnitude and direction of the mechanical response depending on the fiber formulation. Statistical analysis confirmed that compressive strength was significantly affected by fiber type, dosage, and their interaction, whereas no statistically significant effect was detected for flexural strength at the 95% confidence level. The F8 mixture containing 0.10% fibers exhibited the highest compressive strength among the investigated concrete formulations, reaching 28.75 MPa compared with 26.25 MPa for the reference concrete. Flexural strength showed numerical increases of up to 8.2% for selected formulations, although these differences were not statistically significant. Early-age shrinkage was reduced by up to 75% compared with the reference mixtures, representing the most pronounced effect observed in the study. Increasing fiber content reduced workability and promoted fiber agglomeration, highlighting the importance of controlled dosage and dispersion. Among the investigated dosage levels, 0.10% by mass of cement was selected for subsequent durability and microstructural investigations because it provided a favorable overall balance among the evaluated properties for the selected formulations; this dosage should not be interpreted as a universal optimum. The F8 formulation exhibited favorable transport-related properties after 90 days of water curing, while SEM observations indicated a generally homogeneous fiber distribution within the investigated regions. Overall, the results demonstrate the potential of heterogeneous recycled PP textile fibers as reinforcement for cementitious composites under the investigated conditions and provide a systematic multi-scale experimental workflow for their screening and evaluation. Full article

This study investigates the contemporaneous associations between investor sentiment, market microstructure, and daily sectoral returns on Boursa Kuwait. The analysis utilizes daily data spanning from January 2021 to May 2025, integrating sectoral returns, trading volume, liquidity, and volatility proxies alongside a manually constructed sentiment index derived from financial news and market announcements. Ordinary least squares (OLS) regressions were estimated for each sector. Baseline specifications incorporate the High–Low Range, Parkinson volatility, and trading volume, while expanded models include the Log_Amihud illiquidity measure, CC_Volatility, Brent crude oil returns, the Boursa Kuwait All Share Index (AllShare_Return), and the first difference of Central Bank of Kuwait discount rate (D_CBK_DiscountRate). Initial results indicate that investor sentiment is significantly associated with returns in several sectors, though the direction and magnitude of these associations are heterogeneous. Upon controlling for broader market and macroeconomic conditions, the sentiment coefficient remains statistically significant in the Technology and Health Care sectors, with the Technology coefficient changing from positive in the baseline specification to negative in the expanded specification. Liquidity and volatility measures continue to exhibit sector-specific associations. AllShare_Return is positively and statistically significantly associated with returns across most sectors, whereas Brent_Return and the D_CBK_DiscountRate show limited, sector-specific relationships. These findings suggest that broader market conditions account for an important part of daily sectoral return variation, whereas the associations of investor sentiment and market microstructure with returns continue to differ across sectors. Full article

A novel lithium disilicate glass-ceramic modified with Pyrex-derived borosilicate glass and antimony oxide was developed to improve mechanical performance while maintaining chemical stability. The material was fabricated by oxide mixing, melt-quenching, casting, and controlled crystallization, followed by structural and microstructural characterization using field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). Flexural strength, Vickers hardness, and chemical solubility were evaluated according to the relevant ISO standards and compared with those of a commercial lithium disilicate glass-ceramic (IPS e.max CAD; Ivoclar Vivadent, Schaan, Liechtenstein). Statistical analyses were performed using independent-samples t-tests at a significance level of α = 0.05. Structural characterization demonstrated a multiphase crystalline glass-ceramic containing reflections consistent with lithium disilicate, while FE-SEM revealed elongated, partially interlocking crystals distributed within the residual glassy matrix, confirming the development of the intended glass-ceramic microstructure. The experimental material exhibited significantly higher flexural strength than the commercial reference (560.41 ± 53.31 MPa vs. 371.39 ± 14.48 MPa; p < 0.05), whereas Vickers hardness and chemical solubility did not differ significantly between the materials (p > 0.05). These findings suggest that the incorporation of Pyrex-derived borosilicate glass as a glass-network modifier, together with antimony oxide, may provide a viable approach to producing lithium disilicate glass-ceramics with enhanced flexural performance while maintaining hardness and chemical durability, supporting their potential for dental restorative applications. Full article

This study evaluated the mechanical properties and microstructural characteristics of concrete made with recycled concrete aggregates (RCAs) derived from a pier exposed to a tropical marine environment for more than 20 years. The RCA was characterized physically, chemically, and mechanically to assess porosity, inherited chemical contamination, and potential degradation mechanisms associated with prolonged marine exposure. New concretes were produced with 50% replacement of natural coarse aggregates by RCA and water–cement (W/C) ratios of 0.67, 0.61, and 0.47. Compressive strength was measured at 3, 7, and 28 days. The mixture with 50% RCA and W/C = 0.47 achieved a 28-day compressive strength of ≈22.8 MPa, exceeding the design strength of 21 MPa. The source concrete and derived RCA exhibited a thin-section air-void content of 3.3%, acid-soluble chloride content of 0.074% by mass of concrete, and SO₃ content of 1.15%. Petrographic examination identified no evidence of harmful alkali–silica reactivity in the examined material. Statistical analysis of the experimental results indicated increasing compressive strength with decreasing W/C ratio and increasing curing age. These findings demonstrate that, under the investigated mixture proportions and curing conditions, 50% RCA replacement can achieve the specified compressive strength. They also indicate an association between the source concrete’s inherited microstructural characteristics and the strength development of the recycled aggregate mixes. Full article

Quantitative characterization of cement hydration microstructures from X-ray micro-computed tomography (μCT) images is fundamental to understanding hydration mechanisms and developing data-driven cement materials. However, existing deep learning approaches rely heavily on manually annotated datasets, limiting scalability and reproducibility. This study presents a physics-guided artificial intelligence framework for automated characterization of cement hydration microstructures using μCT imaging. A multi-Otsu thresholding strategy, guided by the physical relationship between X-ray attenuation and material density, was developed to automatically generate pixel-level pseudo-labels representing pore space, hydration products, and unhydrated cement. The proposed workflow produced a curated dataset comprising 7638 labeled μCT images extracted from 28 volumetric regions of interest spanning multiple hydration ages, Blaine fineness levels, and water-to-cement ratios. The pseudo-labeled dataset was used to train and evaluate three semantic segmentation architectures: U-Net, Attention U-Net, and U-Net++. All models achieved excellent segmentation performance, with mean Dice coefficients exceeding 0.94, while the baseline U-Net achieved the highest overall accuracy (Dice = 0.9454, IoU = 0.8982). Quantitative analysis of the segmented microstructures successfully captured the expected temporal evolution of pore space, hydration products, and unhydrated cement. ROI-level statistical analysis showed that hydration age, Blaine fineness, and water-to-cement ratio influenced morphological descriptors across the three microstructural phases, revealing systematic differences in microstructural evolution. The proposed framework reduces reliance on manual pixel-level annotation while enabling reproducible and scalable characterization of cement hydration microstructures. These findings provide a foundation for automated μCT-based cement characterization and future materials informatics applications. Full article

Non-radiative carrier loss originating from material defects together with slow charge migration act as two major limiting factors heavily suppressing the power output performance of organic bulk-heterojunction (BHJ) photovoltaic devices (OSCs). Herein, two-dimensional (2D) CdSe nanoplatelets (NPLs) are introduced into conventional P3HT:PCBM and high-efficiency PBDB-T:PCBM photoactive films as multi-purpose doping additives, aiming to finely tune film microstructures, refine interfacial energy level matching, accelerate carrier migration, and eliminate native trap sites inside the active layer. Statistical measurement data verify that 3 mg CdSe NPLs as the ideal doping dosage can realize concurrent performance upgrades for the two distinct OSC architectures investigated here. As for devices built on P3HT:PCBM blend films, the component modified with optimized CdSe NPL additives delivers boosted charge mobility rising from 0.87 × 10⁻⁵ cm²/V·s up to 2.58 × 10⁻⁵ cm²/V·s. Meanwhile, trap site concentration drops markedly from 7.41 × 10¹⁵ cm⁻³ to 4.33 × 10¹⁵ cm⁻³, which lifts the device power conversion efficiency (PCE) from 2.77% to 3.15%. Even more noticeable improvements are observed in PBDB-T:PCBM photovoltaic units; the refined doping recipe raises carrier mobility from 5.42 × 10⁻⁴ cm²/V·s to 8.69 × 10⁻⁴ cm²/V·s and cuts trap density down from 7.13 × 10¹⁶ cm⁻³ to 3.15 × 10¹⁶ cm⁻³, thus bringing about a substantial PCE boost ranging from 6.52% to 9.14%. The present study confirms the bifunctional advantages possessed by 2D CdSe NPLs, which can adjust BHJ microphase separation and electronic characteristics simultaneously. This research offers a simple and broadly applicable route to fabricate organic photovoltaic cells with superior efficiency. Full article

Vanadium slag is an important secondary vanadium resource. Although microwave-assisted calcification roasting improves the leachability of vanadium-bearing phases, further extraction can still be limited during acid leaching, making optimization of the leaching process essential for efficient vanadium recovery. Using this slag, leaching was evaluated at different temperatures, times, liquid-to-solid ratios (L/S), sulfuric acid concentrations, and agitation speeds. A Box–Behnken design (BBD) was used to optimize leaching parameters within the selected ranges. Residue phase composition and microstructure were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). Leaching efficiency increased with temperature, L/S, and acid concentration, but plateaued above 60 °C, 6 mL·g⁻¹, and 14 wt.%, respectively; increases beyond 50 min or 200 rpm gave marginal improvements. Analysis of variance (ANOVA) of the BBD model ranked the statistical effects of the four linear terms within the investigated BBD range as sulfuric acid concentration > L/S > leaching time > temperature. Within the selected BBD parameter ranges, optimization yielded 64.95 °C, 55.21 min, 6.56 mL·g⁻¹, and 15.17 wt.% sulfuric acid, with agitation fixed at 200 rpm. Validation gave an average leaching efficiency of 92.92%, with a relative error of 0.205% compared with the model prediction. After leaching, Mn₂V₂O₇ was undetected. The residue mainly contained irregular particles, 10–30 μm acicular or plate-like CaSO₄·2H₂O crystals, and minor residual vanadium-bearing CrVO₃ and CaVH₂Si₄O₁₂ phases. Surface CaSO₄·2H₂O deposition and refractory-phase encapsulation of vanadium-bearing constituents increased mass-transfer resistance and limited further leaching. This study clarified the relative effects of the investigated leaching conditions on vanadium leaching efficiency within the design range and the interactions among these conditions, and provided microstructural evidence related to the factors limiting further vanadium leaching, thereby providing theoretical guidance for the efficient extraction of vanadium from vanadium slag. Full article

Ornamental palm pruning residues represent a locally abundant, underutilized lignocellulosic waste stream with potential as a waste-valorized epoxy reinforcement. This study investigates the flexural behavior of particulate epoxy composites reinforced with Washingtonia robusta leaf stalk residue, evaluating the influence of reinforcement granulometry on mechanical and microstructural response. Four specimen families were fabricated from a Bisphenol A/F epoxy resin cured with a cycloaliphatic amine hardener: neat resin (RS, reference) and composites reinforced with fine (RF), coarse (RG) and mixed-fraction (RM) particles at 20 vol.% loading. Flexural properties were assessed by three-point bending and fracture surfaces were characterized by SEM. The neat resin exhibited a non-monotonic, viscoelastic-dominated response with no fracture within the extended deformation range tested, whereas all reinforced systems fractured within a substantially narrower window (~8–14.5 mm). RF showed the highest observed flexural modulus (≈15.8 GPa), followed by RM (≈15.4 GPa) and RG (≈14.2 GPa). These differences were not statistically significant (one-way ANOVA, p > 0.05). Damage tolerance followed a similar descriptive trend: RG failed earliest, linked to large interfacial pull-out cavities; RF delayed fracture through crack deflection; and RM showed the most favorable overall balance, combining a modulus comparable to RF with superior crack path tortuosity. These results indicate the potential of Washingtonia robusta, particularly in mixed-granulometry form, as a candidate reinforcement for semi-structural epoxy biocomposites, pending further characterization of properties such as tensile strength, impact resistance, moisture absorption, and long-term durability. Full article