Search Results (487)

Typical specifications for steel fiber-reinforced shotcrete primarily focus on early-age mechanical properties and do not provide much guidance on evaluating changes in capacity over time, particularly under humid underground service conditions. In addition, accelerated laboratory durability tests are rarely calibrated against measurements obtained from underground structures in service. This study addressed that gap with a 12-month dual-track approach: (i) maintaining controlled near-saturated conditions in the laboratory at 23 ± 2 °C and 95–100% relative humidity, with subsequent evaluation of the mechanical properties (compressive strength, splitting tensile strength, and single-fiber pull-out resistance) at 0, 3, 6, 9, and 12 months; and (ii) monitoring the compressive strength in three operating underground silver mines in Zacatecas, Mexico, using the mean 48 h production-control strength as the field reference and cores taken after approximately 12 months of service. The three laboratory trajectories were well described by first-order exponential models (R² ≥ 0.99) throughout the 12-month monitoring period. The observed reductions were 22.0% for compressive strength, 21.4% for splitting tensile strength, and 26.3% for single-fiber pull-out resistance. The apparent pull-out rate constant was approximately 18% higher than the compressive-strength rate constant, though the mechanism for this difference was not identified independently. In the field, there was an apparent reduction in compressive strength of 8–10% after about 12 months. Comparison of the chamber and field compressive-strength rates produced an apparent acceleration factor, AF ≈ 2.7, with a per-mine range of 2.4–3.0. The high pairwise correlations among the three laboratory properties (r ≥ 0.996) and the first PCA component, which explained 99.8% of their standardized trajectory variance, reflected closely aligned temporal trends. However, since these were based on five exposure-age means, they should be considered only exploratory evidence of co-variation rather than causation. MANOVA demonstrated significant multivariate effects on the combined compressive and splitting tensile responses across exposure ages (p < 0.001). The proposed acceleration factor is preliminary and restricted to the materials, sites, exposure context, and observation period studied. Routine compressive-strength core testing may be useful as a practical screening indicator, but it cannot quantitatively replace direct bond or post-cracking evaluation. Full article

Interferometric fiber-optic hydrophones are widely deployed in passive underwater acoustic detection systems due to their high sensitivity, broad dynamic range, and immunity to electromagnetic interference. However, their adoption in active acoustic systems has been largely constrained by the limited operational bandwidth of conventional architectures. Through coupled acoustic–structural simulations, this work identifies the operational bandwidth bottleneck as arising from low-order mechanical resonance of high-modulus mandrel structures combined with acoustic cavity resonance and near-field scattering within the enclosed cylindrical geometry. To address these limitations, an optimized push–pull mandrel structure, featuring a miniaturized profile of φ16 mm × 16 mm and a low-acoustic-impedance material, is implemented to eliminate mechanical resonance within the operational bandwidth. Additionally, an integrated acoustic metamaterial liner is incorporated into the inner tube to mitigate scattering and reverberation effects. Experimental characterization of the prototype demonstrates an average phase sensitivity of −132 dB re 1 rad/μPa, with fluctuations below ±1.5 dB across 20 Hz to 31.5 kHz. Utilizing a custom-built demodulation system, the hydrophone achieves a minimum detectable pressure of 42 dB re 1 µPa/√Hz (126 µPa/√Hz) at 20 Hz and 27 dB re 1 µPa/√Hz (22 µPa/√Hz) above 2 kHz, remaining over 28 dB below the deep-sea state zero ambient noise floor at 20 Hz, and hence confirms its passive acoustic monitoring capability. In the high-frequency regime above 2 kHz, the hydrophone maintains ±1.5 dB sensitivity flatness with a horizontal directivity variation of only ±1.51 dB at 30 kHz, providing a robust platform for broadband active acoustic applications, including active sonar, underwater acoustic imaging and acoustic communications. These results establish a viable pathway toward next-generation dual-mode underwater acoustic systems requiring both high-fidelity passive listening and broadband active detection. Full article

Health systems are complex adaptive systems whose structural uncertainty limits prediction-based planning, and generative AI is increasingly proposed to enrich the foresight used to navigate them. Whether cheaper, more fluent scenario production actually improves collective strategic judgement, however, remains largely untested in real organisations. This article reports a research-through-design study of an AI-assisted participatory foresight process run for the planned Girona Health Campus (Catalonia): ten domain workshops with about 250 professionals, 170 AI-assisted scenario drafts, and an organisation-wide SmartDelphi validation. Reconstructing the process abductively from its documentation, three behaviours recur. Generation increased the number of scenarios but not the range of futures they covered, pulling repeatedly toward technological resolution: 80% of the analysed scenarios referenced technology and 61% were legible as techno-optimistic accounts. The decisive work therefore migrated downstream to synthesis, where situated meaning was preserved, diluted, or lost. The characteristic failure mode was not poor output but over-trust in fluent output, which participants countered only when the design required them to contest and restate it. Validation itself functioned as organisational diagnostics, exposing a consistent desirability–feasibility gap that varied with the kind of change each future demanded. We consolidate these findings into five transferable design principles and argue that, once the capacity to imagine futures becomes abundant, methodological attention must shift from producing more scenarios to managing that abundance while safeguarding quality. Full article

This study clarifies how rarefaction-induced wall slip in a thin gas film affects the established inverse-cubic scaling law for the spatial nonuniformity of levitation pressure in a push–pull levitation stage. The levitation force in this stage is generated by the combined action of blowing and suction. The continuum-based stress description is retained, and only the wall boundary condition is changed from the no-slip condition to a first-order slip condition. Three-dimensional incompressible unsteady Stokes simulations in a thin-gap unit-cell model are combined with a lubrication-theory scaling analysis. The effects of levitation height, blowing-velocity distribution, port-radius ratio, and computational-domain width are examined systematically. The results show that wall slip has only a minor influence at relatively large levitation heights. As the levitation height decreases, however, rarefaction-induced slip increases the flow-rate conductance. Consequently, the intensity of the spatial variation in levitation pressure is systematically reduced below that predicted by the no-slip inverse-cubic scaling law. This departure is well described by a correction relation derived from the lubrication approximation and remains robust against changes in the prescribed blowing-velocity distribution and geometric conditions. These findings provide an incompressible baseline for predicting levitation-pressure nonuniformity within the nominal gap-based Knudsen-number range examined here. Full article

The transition from conventional silica nanoparticle (SiNP) production based on purified alkoxysilanes and high-temperature flame hydrolysis of silicon tetrachloride to renewable and waste-derived silicon resources requires more than precursor substitution. It requires a mechanistic understanding of how feedstock mineralogy, silicon speciation, impurity chemistry, and processing history propagate through dissolution, nucleation, condensation, gelation, aging, drying, and pore evolution to determine material performance, environmental burden, and manufacturing feasibility. Although previous reviews have established the technical feasibility of producing silica from secondary resources, their predominant organization by feedstock, synthesis route, or application provides limited ability to explain why nominally similar processes generate materials with markedly different structural and functional properties. This review addresses these through a resource-pull, feedstock-to-function framework that links resource chemistry and process design to critical material attributes, application-specific specifications, sustainability, and scale-up requirements. Agricultural residues, industrial by-products, geothermal resources, waste glass, and fluorosilicate streams are critically compared according to silicon form and phase, reactivity, impurity profile, compositional variability, purification demand, and attainable product quality. Particular attention is given to waste-derived alkaline silicate systems, in which molecular, oligomeric, and colloidal silica coexist and therefore require characterization beyond bulk SiO₂ concentration. Established and emerging processing strategies, including controlled combustion and alkaline extraction, alkali fusion, ambient-pressure drying, microwave and mechanochemical activation, biogenic and biomimetic templating, and continuous processing, are evaluated according to their mechanistic effects, technological maturity, structural control, and demands for energy, reagents, water, solvents, effluent treatment, and capital. Across these routes, gelation and aging emerge as critical transfer stages through which feedstock composition is translated into network connectivity, pore architecture, shrinkage behavior, and ultimately functional performance. Evidence from secondary-source aerogels further shows that properly controlled waste-derived systems can attain BET surface areas of approximately 350–500 m² g⁻¹, within the textural range of many alkoxide-derived materials, indicating that feedstock variability, impurity management, and process control are more important constraints than an inherently lower performance ceiling. On this basis, this review proposes a minimum evidence framework comprising feedstock traceability, intermediate-speciation and colloidal characterization, silicon mass balance, gelation and aging metrics, application-specific qualification criteria, performance-normalized life cycle and techno-economic assessment, process analytical control, and staged pilot validation. Collectively, these principles provide a mechanistically grounded basis for moving sustainable silica synthesis beyond isolated proof-of-concept demonstrations toward reproducible, scalable, application-matched, and commercially credible manufacturing platforms. 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

This pilot in vitro study explored the tensile retention of lithium disilicate and monolithic zirconia crowns cemented onto zirconia one-piece implants using two resin cements and two cementation protocols. In addition, the relationship between micro-computed tomography (micro-CT)-derived cement layer characteristics and retention was explored for lithium disilicate crowns. Thirty-two implant–crown assemblies were prepared using 16 lithium disilicate and 16 zirconia crowns. Specimens were cemented with either an adhesive resin cement (Panavia V5) or a self-adhesive resin cement (SpeedCem Plus) using two protocols: conventional apical-half cementation (AH) and an abutment-assisted apical-half protocol (A-AH). Cement thickness and porosity for lithium disilicate crowns were obtained from a previously published micro-CT analysis of the same specimens; no micro-CT measurements were available for the zirconia specimens. Tensile pull-out testing was performed using a universal testing machine. The primary outcome was the maximum recorded force at the first observed mechanical failure, irrespective of the mode of that failure, so that all 32 specimens contributed a value. Failure occurred by crown debonding in 27 specimens, by crown fracture in 4 and by implant fracture in 1. For the primary outcome, the maximum recorded force was lower for lithium disilicate than for zirconia crowns (medians 347.20 versus 596.05 N; exact Mann–Whitney p = 0.017) and lower with the A-AH than with the AH protocol (medians 304.24 versus 614.38 N; p < 0.001), whereas the difference between the two resin cements was not statistically significant (medians 438.88 versus 550.83 N; p = 0.210). The highest observed mean maximum load was recorded for zirconia crowns cemented with Panavia V5 using the AH protocol (729.9 ± 237.7 N), whereas the lowest observed mean maximum load was recorded for lithium disilicate crowns cemented with Panavia V5 using the A-AH protocol (219.7 ± 105.1 N). In a secondary, cause-specific exploratory analysis restricted to crown debonding (27 events, 5 specimens censored at fracture), Cox proportional hazards regression on the applied-force scale gave hazard ratios of 3.75 (95% CI 1.40–10.01) for lithium disilicate versus zirconia, 6.47 (2.39–17.53) for A-AH versus AH and 1.82 (0.76–4.39) for Panavia V5 versus SpeedCem Plus. For lithium disilicate crowns, exploratory factorial ANOVA indicated that cementation protocol was associated with differences in cement thickness (p = 0.035), while cement type was associated with differences in porosity (p < 0.001). All 16 lithium disilicate cement thickness observations lay between 253.29 and 254.96 µm, a total span of 1.67 µm. Within that extremely restricted range, a univariable exploratory Cox model expressed per 0.1 µm gave a hazard ratio for debonding of 1.24 (95% CI 1.03–1.48; p = 0.024); this is an unadjusted association across a range that is itself associated with cementation protocol, and it does not demonstrate a clinically meaningful or independent effect of cement thickness. No association was detected for total porosity (0.959 per percentage point, 0.717–1.283); that interval is wide and indicates absence of evidence rather than evidence of no association. Within the limitations of this pilot in vitro study—four specimens per subgroup, wide confidence intervals and no adjustment for multiplicity—the findings suggest that crown material and cementation protocol may be associated with retention patterns. They are exploratory and hypothesis-generating and require confirmation in larger, independently powered studies. Full article

The rapid development of implantable medical electronics requires robust biocompatible coatings capable of ensuring long-term stability in aggressive physiological environments. Although Grade 1 titanium is widely used for its excellent mechanical properties and corrosion resistance, active implants require defect-free insulating coatings to prevent electrical leakage and metal ion release. This study presents a systematic evaluation of Parylene C (P-C) thin films deposited by the Gorham chemical vapor deposition (CVD) process onto implant-grade titanium substrates. Four coating thicknesses (1, 5, 10, and 20 µm) were deposited and characterized using complementary chemical, morphological, optical, and mechanical techniques. Contact-angle measurements confirmed uniform hydrophobicity (90.56 ± 1.86°), while FTIR and EDX verified the characteristic chemical composition of P-C. Reflectometry, ellipsometry, and interferometry demonstrated excellent thickness control and deposition reproducibility. Pull-off testing showed high initial mechanical integrity, with detachment forces ranging from 52 to 73 N. However, accelerated PBS ageing (21 days at 90 °C) induced significant degradation, particularly for thicker coatings, reducing pull-off forces to 19–42 N. Likewise, thermal-shock cycling (−80 °C to +220 °C) caused severe interfacial damage, decreasing the required detachment force to approximately 5.5 N for 20 µm coatings because of extensive cracking and delamination. These results demonstrate that Parylene C provides excellent conformal coverage and chemical stability on titanium but that its durability is significantly affected by prolonged hydrothermal ageing and extreme thermal loading. This study provides practical guidelines for the design of reliable encapsulation systems for active implantable medical devices and highlights the need for improved interfacial engineering through optimized adhesion-promoting layers or hybrid protective architectures. Full article

Optical microfibers are fabricated by pulling classical silica fibers until reaching diameters of a few micrometers or less. These devices are significantly exploited in many science and engineering fields, ranging from fundamental research to practical applications. Despite their many attractive advantages, a major technological challenge remains: heating caused by laser absorption from surface defects and contaminants. In the present study, we propose, for the first time to our knowledge, a novel method to measure the temperature evolution of laser self-heated microfibers in air at a wavelength of 1.48 µm. This method, simple and fast, enables us to investigate the influence of the diameters and lengths of the microfibers. We found that the temperature of the microfibers increases linearly with the power and measured a rise of 70 °C for a 1 µm diameter and 20 mm length microfiber at a moderate power of 160 mW. A numerical model considering the microscale and the heat exchange with air is proposed and is adjusted with experimental data, providing values for the thermal transfer coefficient. By investigating power scaling, this work enables the prediction of temperature increases in self-heated microfibers in air, paving the way for new insights into the self-cleaning of microfiber-based devices and for optimized control of light propagation at high power levels. Full article

Ultra-deep lattice-like fractured carbonate reservoirs, formed by multi-period tectonic movements, feature strong heterogeneity, multi-scale fracture nesting, and anisotropic in situ stress. However, hydraulic fracture (HF) propagation behaviors within these complex formations remain poorly understood. In this study, using an unstructured fracture network approach, we simulated HF propagation in two typical fault-controlled lattice-like structures: compressive-torsion and pull-apart overlap zones. The performance of commingled, staged, and temporary plugging fracturing was evaluated, alongside sensitivity analyses of wellbore orientation, plugging timing, pump rate, and fluid viscosity. Results indicate that HFs in compressive-torsion zones exhibit long, straight geometries with local tensile activation points. Conversely, pull-apart overlap zones promote step-shaped, multi-branched fractures with superior lateral connectivity. The optimal timing for temporary plugging exhibits a delayed trend with increasing natural fracture density, ranging from 50% to 70% of the fracturing process in compressive-torsion zones, whereas an earlier implementation is preferred in pull-apart overlap zones, occurring at 33–65% of the fracturing process. Furthermore, HFs in compressive-torsion zones are less sensitive to viscosity and pump rate. To optimize stimulated volume, a moderate viscosity of 50–60 mPa·s is universally recommended. Regarding pump rates, 8–10 m³/min is ideal for balanced connectivity in pull-apart overlap zones, whereas >12 m³/min is required for compressive-torsion zones. These findings provide critical theoretical and engineering guidelines for differentiated fracturing strategies in ultra-deep reservoirs. Full article

CaO-based alkali-activated high-strength cementless concrete is considered an environmentally friendly and cost-effective material for sustainable structures; however, to enable its structural application, the bond behavior between steel bars and cementless concrete must be properly assessed. This study experimentally investigates the local bond performance and bond–slip behavior of cementless concrete in comparison with existing design guidelines. For this purpose, steel bars were embedded in cube specimens with dimensions of 150 × 150 × 150 mm³, and direct pull-out tests were conducted. The test variables included embedded length (2d, 4d, and 6d), bar diameter (D10 and D13), and concrete cover thickness (1.5d, 2.5d, and 7d). The results indicate that increasing the bar diameter did not lead to a significant change in bond strength; instead, the bond strength increased by approximately 4.8%, and yielding of the steel bar at the loading end was observed for specimens with an embedded length of 6d. When the cover thickness exceeded 2.5d, its influence on bond strength enhancement became negligible, with similar bond strengths ranging from 23 to 25 MPa. A comparison of the ultimate bond strength revealed that the predicted values based on ACI 318-25 showed the best agreement with the experimental results, with the lowest mean absolute relative deviation (MARD) of 22.14%. Furthermore, in terms of bond–slip behavior, the CMR model demonstrated better agreement with the experimental results than the modified BPE model, exhibiting a coefficient of determination ($R^2$) of 97%. Full article

Conventional bond-slip models generally represent ribbed GFRP bars as equivalent smooth cylinders, limiting their ability to describe local rib-bearing, interface degradation, and non-uniform stress transfer. This study establishes a three-dimensional finite-element model for helically ribbed GFRP bars embedded in concrete, explicitly incorporating the helical rib geometry, cohesive-frictional interface interaction, and concrete damaged plasticity. Validation against independent pull-out tests yields minor peak bond-stress errors of −0.55% and −2.49% across different bar diameters, with numerical reliability confirmed through mesh and energy checks. The results indicate that bond resistance evolves from cohesive transfer to rib-bearing action, followed by localized concrete damage, frictional sliding, and residual interlocking. Stress transfer is highly non-uniform along the bonded length, and post-peak interface degradation causes the active transfer zone to migrate dynamically away from the loaded end. Parametric analyses reveal conditional main-effect trends within the investigated ranges, demonstrating that rib height has the strongest influence on residual resistance and energy dissipation, whereas the benefit of increasing concrete strength gradually diminishes. Increasing the bonded length or bar diameter raises the total pull-out force but reduces the nominal bond efficiency due to shear lag. Finally, a simplified four-stage bond-slip relationship is proposed, wherein each stage physically aligns with distinct interface degradation phases, to facilitate computationally efficient structural-scale simulations. Full article

Plyometric training is proposed as a method for improving neuromuscular performance in climbing; however, its specific effects on upper-body explosive power and rate of force development (RFD) in male boulderers, ranging from trained to highly trained, remain unclear. This preliminary exploratory trial examined the effects of a 10-week plyometric training program on selected laboratory-based neuromuscular performance outcomes. Eighteen male climbers were assigned to: intervention group (n = 9, 29.7 ± 4.5 yr) or a control group (n = 9, 31.3 ± 5.6 yr). Finger flexor strength and RFD (20-mm grip, 0–200 ms, 20–80%), isometric pull-up strength and RFD (load cell), upper-body power (plyometric push-up, Power Slap), and lower-body power (CMJ) were assessed. The intervention comprised two plyometric sessions/week for 10 weeks. Significant differences were observed in pull-ups (Δ difference = +3.89 repetitions; 95% CI: 0.30, 7.48; p = 0.036; η²p = 0.248), push-up power (Δ difference = +174.25 W; 95% CI: 5.05, 343.46; p = 0.044; η²p = 0.230), isometric pull-up RFD 0–200 ms (Δ difference = +107.85 kg/s; 95% CI: 27.54, 188.16; p = 0.012; η²p = 0.336), and the 20–80% range (Δ difference = +261.78 kg/s; 95% CI: 23.09, 500.47; p = 0.034; η²p = 0.253). No clear between-group differences were observed for finger flexor strength, finger RFD, maximum isometric pull-up strength, Power Slap, or CMJ. Given the exploratory design, small sample size, and low reliability of RFD-derived variables, these findings should be interpreted cautiously as preliminary evidence of movement-specific neuromuscular performance improvements. Full article

This study examines the impacts of key abrasive water jet machining (AWJM) parameters on the machinability of AA7175–15 wt.% ZrB₂ metal matrix composites produced via a two-step stir casting route. Jet pressure (100–300 MPa), traverse speed (70–130 mm/min), standoff distance (3–5 mm), and abrasive flow rate (250–450 g/min) were systematically varied to evaluate their effects on surface roughness (Ra), kerf taper angle (KA), and material removal rate (MRR). The experimental setup was designed using response surface methodology based on a central composite design (RSM–CCD), enabling both interaction and curvature effects to be assessed. Analysis of variance indicates that jet pressure exerts the strongest influence on MRR, which may be attributed to the increased kinetic energy and penetration capability of abrasive particles at higher pressures. In contrast, traverse speed was found to play a dominant role in controlling surface roughness and kerf geometry. As traverse speed increased, Ra and kerf taper angle tended to rise, likely due to reduced jet–material interaction time and incomplete erosion of the hard ZrB₂-reinforced matrix. Abrasive flow rate contributed positively to MRR up to higher levels, although its effect appeared secondary compared to jet pressure. Regression models developed for all machining responses showed strong predictive performance, with coefficients of determination exceeding 0.95 and statistically insignificant lack-of-fit, suggesting adequate representation of the underlying process behaviour within the investigated parameter range. Scanning electron microscopy of the machined surfaces revealed erosion features such as abrasive ploughing, particle pull-out, and striation formation. These surface morphologies are consistent with the observed variations in Ra and kerf characteristics and reflect the combined ductile–brittle erosion response of the composite. Overall, the study identifies optimised AWJM parameter combinations that can improve both surface quality and machining efficiency when processing AA7175–ZrB₂ composites. Full article

In this study, the effect of stacking sequence on the mechanical behavior and damage evolution of carbon- and glass-fiber-reinforced hybrid composite tubes manufactured by the filament winding method was experimentally investigated. The tubes were produced from E-glass and carbon fibers in a Huntsman epoxy matrix, with an inner diameter of 22.5 mm and an outer diameter of 28.5 mm, in two configurations that differ in both the fiber placed in each layer and its winding angle: an inner [±45]₂ carbon layer/outer [±75]₂ glass layer (C45) and an inner [±45]₂ glass layer/outer [±75]₂ carbon layer (G45). The fiber volume fractions ranged from 0.53 to 0.61 and the measured densities from 1.68 to 1.84 g/cm³. Five specimens per configuration (n = 5) were tested under radial compression and three-point bending, and their fracture mechanisms were characterized by scanning electron microscopy (SEM) and optical microscopy. Energy absorption was quantified through the specific energy absorption (SEA). Under radial compression, the C45 configuration exhibited a higher peak force (4209 ± 322 N versus 3573 ± 136 N) and a higher SEA (2.64 ± 0.13 J/g versus 2.06 ± 0.03 J/g). Under three-point bending, C45 again reached a higher flexural strength (92.8 ± 4.5 MPa versus 85.1 ± 3.0 MPa); however, despite failing at a markedly lower peak force, the G45 configuration absorbed a comparable total energy (66.96 ± 2.83 J versus 62.88 ± 6.26 J) and reached a comparable SEA (1.13 ± 0.06 J/g versus 1.08 ± 0.14 J/g), reflecting the ductility-driven damage tolerance imparted by the glass inner layer. Across all metrics, the G45 configuration displayed a consistently lower coefficient of variation (e.g., 3.82% versus 7.64% for radial peak force), indicating greater reproducibility and structural predictability. SEM observations revealed that the C45 specimens failed through sudden fiber fracture and delamination driven by the high stiffness mismatch, indicating brittle behavior, whereas the G45 specimens exhibited progressive damage through matrix crushing and fiber pull-out. The findings indicate that the C45 configuration is favorable where maximum load-bearing capacity and stiffness are targeted, whereas the G45 stacking sequence is advantageous where energy absorption, damage tolerance, and predictable progressive failure are critical. Full article