Search Results (560)

The mechanical behavior of S135 and V150 (Mo-V-Nb microalloyed) drill pipe steels was systematically investigated at room temperature (RT) and elevated temperatures (100–300 °C), alongside the microstructural evolution after long-term thermal exposure at 310 °C (200–500 h). V150 steel exhibits a superior RT yield strength (1099 vs. 1012 MPa) relative to S135, attributed to grain refinement and precipitation strengthening from nanoscale MC precipitates. However, at 200–300 °C, S135 steel displays strength recovery due to dynamic strain aging (DSA) facilitated by the formation of Cottrell atmospheres. Conversely, in V150 steel, V and Nb pin free interstitial atoms, suppressing Cottrell atmosphere formation and DSA. Consequently, V150 cannot gain DSA-induced strengthening, resulting in a steeper yield strength decline (a 17.3% drop at 300 °C versus 11.5% for S135). Long-term thermal exposure further reveals divergent microstructural evolution: S135 steel achieves synchronous improvements in strength and ductility via the transformation of coarse M₃C into stable alloy carbides and the precipitation of nanoscale Mo-enriched carbides. In contrast, V150 steel undergoes Ostwald ripening and coherency loss of high-volume-fraction nano-MC precipitates, weakening dislocation pinning and accelerating dislocation annihilation, ultimately leading to the simultaneous degradation of strength and ductility. This study elucidates that while Mo-V-Nb microalloying enhances RT strength, it compromises high-temperature mechanical stability. Full article

This study investigates the evolution of microstructural, mechanical, and transport properties in AZ31 magnesium alloy surface composites reinforced with Ti₂AlC MAX-phase particles at volume fractions of 6, 9, and 12 vol.%, which were fabricated by solid-state friction stir processing (FSP). In contrast to conventional brittle ceramics, Ti₂AlC MAX-phase mitigates interfacial reactivity and thermal mismatch. FSP successfully fabricated a highly consolidated, macroscopically defect-free, dynamically recrystallized fine-grained stirred zone with homogeneous particle distribution and metallurgically clean interfaces. Mechanically, the addition of 12 vol.% Ti₂AlC significantly improved the elastic response, increasing the Young’s modulus from 51 GPa to 67 GPa. The microhardness of the stirred zone reached 60.14 HV, a 53.4% increase over the base metal. The controlled electron and phonon scattering, enabled by the introduction of heterogeneous Mg/Ti₂AlC interfaces, decreased the electrical and thermal conductivities from initial values of 1.15 × 10⁷ S/m and 86.0 W/m·K for the unreinforced matrix down to 7.8 × 10⁶ S/m and 76.0 W/m·K, respectively, and caused a significant reduction in the coefficient of thermal expansion. Theoretical analysis, utilizing the Wiedemann–Franz law and Maxwell–Eucken approximations, provided a supportive baseline indicating the dominance of electronic thermal transport and interfacial scattering mechanisms. These results outline a viable route for developing lightweight magnesium-based composites with tailored mechanical and thermal characteristics for advanced structural applications. Full article

Background/Objectives: The implementation of tattoo-free radiotherapy (RT) for breast cancer reflects an effort to mitigate the psychological distress of permanent marks through surface-guided techniques, while simultaneously evaluating its utility in meeting setup precision requirements. Methods: In this prospective trial, patients were positioned for breast cancer RT including regional nodal irradiation exclusively using surface-guided RT (SGRT). Cone-beam computed tomography (CBCT) was acquired at each fraction as the ground truth to analyze translational setup deviations. Results: A total of 457 paired SGRT–CBCT data points in 30 patients were acquired. A residual translational setup deviation of ≤6 mm was achieved in 97.6% of all fractions with a median deviation of 2 mm (range: 0–12). Neither age, comorbidities, body mass index, extent of target volumes, choice of breathing technique, nor patient-reported symptoms (pain, dermatitis, anxiety) correlated significantly with setup deviations. The median in-room positioning time was 92 s (range: 20 s–6 min and 37 s) and significantly prolonged in patients with an elevated BMI and higher grades of pain and skin dermatitis, and for chest wall irradiation. Manual assessment of the accuracy of regional nodal CTVs in each CBCT relative to the planning CT showed good-to-minor deviations in 99.7% (Level 1/2), 95.0% (Supra-/infraclavicular), and 90.8% (Internal mammary), respectively, with major deviations in only 0.3% (Level 1/2), 5.0% (Supra-/infraclavicular) and 9.2% (Internal mammary). A forward dose calculation on CBCT geometries (n = 86) revealed high median CTV dose coverage of 100.0% (range: 57.1–107.7%) of the original target dose for all lymph node levels combined. Conclusions: The tattoo-free positioning setup for regional nodal irradiation in breast cancer patients exhibited pronounced robustness, maintaining its accuracy and reliability irrespective of patient-, tumor-, or treatment-specific variables with high clinical efficiency. However, larger cohorts are required to confirm whether these parameters genuinely operate independently of setup accuracy. Full article

Fischer–Tropsch (FT) wax is widely used as an organic warm-mix asphalt (WMA) additive, lowering binder viscosity during construction while improving high-temperature deformation resistance in service; however, the comparative responses of SBS-modified asphalt to different FT wax grades remain insufficiently understood. Sasobit and three FT waxes with different carbon-chain ranges (FT 80, FT 90, FT 100) were incorporated into SBS-modified asphalt at about 7.0 wt%, and their effects on macroscopic performance, rheology, molecular packing, and diffusion were evaluated using physical-property tests, rotational viscosity, dynamic shear rheometer (DSR) testing, and molecular dynamics (MD) simulation. In the MD analysis, the wax additives were represented by linear alkane molecules with different chain lengths, and the systems were subjected to structural optimization, annealing, and NPT equilibration using the COMPASS III force field before the molecular descriptors were evaluated. The experimental results showed that all four additives produced a trade-off between increased high-temperature stiffness and reduced low-temperature ductility. Sasobit gave the strongest viscosity reduction (>70% above 165 °C), while FT 90 and FT 100 showed more stable, predictable viscosity–temperature behavior favorable for a wider construction window. DSR results showed higher complex modulus and lower phase angle for all modified binders at low frequencies, suggesting an increased elastic contribution and greater resistance to deformation under the tested rheological conditions; FT 80 produced the greatest stiffening but also the largest free volume and loosest molecular packing, whereas FT 100 increased cohesive energy density and reduced free volume, reflecting denser packing and stronger intermolecular cohesion. MD simulations revealed that FT wax enhanced short-time local molecular mobility and segment diffusion in its molten state (explaining the warm-mix viscosity reduction), whereas macroscopic stiffening and ductility loss at ambient temperatures were dictated by wax microcrystallization and physical network constraints that restricted long-range chain relaxation. By comparing three FT wax grades and Sasobit under the same experimental dosage and testing framework, this study provides a controlled assessment of the relationships among wax-grade characteristics, binder-scale rheological responses, and MD-derived molecular descriptors. Full article

To overcome the limitations of conventional numerical simulations of cemented gangue backfill (CGB), this study developed a refined PFC2D model that incorporates the actual particle size distributions of coal gangue and river sand. Randomly distributed steel fibers were generated using FISH programming. Based on uniaxial compression tests and scanning electron microscopy (SEM) observations, the influence of steel fibers on the mesoscopic damage mechanism of CGB is systematically investigated. The results indicate that: (1) the refined model significantly improves the reliability of numerical simulations, accurately reproducing stress concentration within coarse aggregates and the steel fiber “bridging effect”; (2) a steel fiber volume fraction of 0.8% optimizes force chain distribution and suppresses crack propagation, promoting a transition in failure mode from brittle shear failure to ductile compressive–extrusion failure mode, with the peak strength and residual strength increased by 23.7% and 40.2%, respectively, compared with the fiber-free specimen; (3) PFC simulations reveal that steel fibers markedly retard damage accumulation by modifying the force chain network and crack propagation paths; and (4) SEM analysis demonstrates that steel fibers enhance the toughening effect through the interfacial transition zone, whereas excessive fiber content (1.2%) leads to fiber agglomeration and a 62.5% increase in porosity, resulting in performance deterioration. This study provides a robust theoretical framework for gradation reconstruction and refined fiber modeling in the design of roadside backfill materials. Full article

Background/Objectives: Image-guided adaptive brachytherapy is a core component of definitive treatment for locally advanced cervical cancer (LACC). However, implantation remains challenging in bulky, asymmetric, or anatomically complex tumors, where standard applicator geometry or purely straight interstitial trajectories may be insufficient for individualized target coverage. This study evaluated the real-world implementation of a patient-specific 3D-printed template-guided adaptive brachytherapy workflow for complex LACC. Methods: We retrospectively reviewed 120 consecutive patients with FIGO 2018 stage IB3–IVA cervical cancer treated with definitive chemoradiotherapy followed by high-dose-rate image-guided brachytherapy between March 2023 and March 2025. All patients were treated using a patient-specific 3D-printed template-guided hybrid intracavitary/interstitial workflow integrating CT/MRI-based target assessment, individualized catheter trajectory planning, template fabrication, implantation verification, and adaptive treatment planning. Straight-channel or curved-channel guidance was selected according to residual tumor geometry and pelvic anatomy, with flexible plastic interstitial catheters used for curved or anatomically constrained trajectories. Procedural deliverability, dosimetry, toxicity, early clinical outcomes, and exploratory dose–outcome patterns were analyzed. Results: The median HR-CTV volume was 55.9 cm³, and the median HR-CTV D90 was 92.9 Gy EQD2. Median organ-at-risk D2cc values remained within contemporary institutional and guideline-consistent constraints. A total of 555 template-guided HDR brachytherapy fractions were delivered. The median applicator-and-catheter placement time was 4.21 min per fraction, with a median of 7.25 implanted channels. Minor and major insertion-related bleeding occurred in 10.8% and 1.7% of patients, respectively. At a median follow-up of 20.1 months, estimated 3-year overall survival, progression-free survival, local recurrence-free survival, regional recurrence-free survival, and distant metastasis-free survival were 77.9%, 76.8%, 94.3%, 98.0%, and 86.2%, respectively. Late grade ≥ 3 gastrointestinal and genitourinary toxicities occurred in 2.5% and 1.7% of patients, respectively, with no grade 4–5 events. Exploratory dose–outcome analyses suggested hypothesis-generating dose–outcome patterns, but these findings were not intended to define or validate a clinical dose threshold. Conclusions: This real-world implementation study supports the feasibility of patient-specific 3D-printed template-guided adaptive brachytherapy for complex LACC. By translating CT/MRI-based individualized trajectory planning into template-guided intracavitary/interstitial catheter placement, this workflow achieved guideline-consistent target coverage, acceptable organ-at-risk doses, efficient procedural delivery, and low severe toxicity within the available follow-up. Dose–outcome findings remain exploratory and require validation in more mature cohorts. Full article

Graphene, with excellent mechanical and self-lubricating properties for polymer modification, can be single- or multi-layered (3–10 layers). In this study, molecular dynamics simulations have been employed to qualitatively explore the relative trends and internal modification mechanism of polyimide (PI) modification by single-layer graphene and three-layer graphene with different sizes. Small-sized single-layer graphene (SSLG), small-sized multi-layer graphene (SMLG), large-sized single-layer graphene (LSLG), and large-sized multi-layer graphene (LMLG) were introduced into the PI matrix at an identical mass fraction with initially uniform dispersion during model construction. The tensile mechanical and frictional behaviors of graphene-modified PI were systematically examined. The results indicate that graphene addition effectively improves both the mechanical and tribological properties of PI. At a fixed filler mass fraction, SSLG exhibits the strongest interaction with PI, with a binding energy of 396.8 kJ/mol. The fractional free volume of SSLG-reinforced PI reaches 15.3%, which is considerably lower than the value calculated for pure PI (20.3%). The average elastic modulus of the SSLG-modified PI is 70.4% higher than that of pure PI, an increase which exceeds that of the SMLG-modified PI (45.2%), LSLG-modified PI (26.5%), and LMLG-modified PI (14.0%). In terms of tribological properties, the SMLG-modified PI exhibits optimal friction with an average friction coefficient of 0.105, which is 48.3% lower than that of pure PI and lower than the values for the SSLG (0.138), LSLG (0.156), and LMLG (0.182) systems. This work mainly draws qualitative structure-property rules and provides key theoretical fundamentals and design principles for tailoring the mechanical and tribological performance of high-performance graphene-reinforced polyimide composites. Full article

The absence of a gluten network remains the main technological limitation in developing high-quality gluten-free sponge cakes, leading to poor structure, reduced volume, and impaired texture. This study aims to develop a functional gluten-free sponge cake by partially substituting rice flour with amaranth flour (5 to 15%) and tiger nut flour (25 to 35%), while optimizing the formulation to achieve a 35–45% reduction in added sugar compared to the traditional control cake, in order to improve the antioxidant and technological quality of the product. Several formulations were compared to a positive control (wheat) and a negative control (rice) by combining physicochemical, biochemical, and crumb structure analysis. The parameters evaluated include weight loss, specific volume, moisture, water activity (a_w), texture profile analysis (TPA), crumb cell analysis, color, antioxidant potential and sensory acceptability. This study showed that the incorporation of amaranth and tiger nut flours improved the functional, physicochemical, textural, antioxidant, and sensory properties of gluten-free sponge cakes. Among all formulations, F8, which consisted of 60% rice flour, 10% amaranth flour and 30% tiger nut flour with 60% sugar, exhibited the best overall performance (p < 0.05), with a higher specific volume (5.84 cm³/g), higher moisture content (28.76%) and lower water activity (0.58 for the crust and 0.54 for the crumb), the highest area fraction (27.73%), stronger antioxidant activity (1.80 mg AAE/g dw), and the highest sensory acceptability (7.23) (p < 0.05). These results highlight the potential of combining these flours to develop highly acceptable gluten-free bakery products. Full article

Objective: This study aimed to assess the relationship between excess epicardial fat and the patterns of perioperative myocardial remodeling in patients undergoing surgical correction of mitral valve (MV) disease. Methods: A total of 148 patients with acquired non-infectious MV disease scheduled for surgical correction under cardiopulmonary bypass were screened in this prospective observational non-randomized study. Preoperative computed tomography (CT) of the heart was performed to assess epicardial adipose tissue (EAT) volume. Transthoracic echocardiography (Echo), including evaluation of left ventricular (LV) global longitudinal strain (GLS), right ventricular (RV) free-wall longitudinal strain, and RV systolic function (3D Echo), was conducted preoperatively, as well as postoperatively during one year after surgery. Analysis of postoperative myocardial remodeling and complications within one year after surgery was performed. Patients were divided into groups before surgical correction of MV based on the (1) EAT volume, associated with atrial fibrillation (AF) presence (EAT volume less than or > 115.1 cm³ by CT), and (2) EAT volume, associated with the presence of at least three metabolic factors (EAT volume less than or ≥100.6 cm³). Results: Prior to MV correction, Echo showed that patients with EAT volume > 115.1 cm³ exhibited larger left and right atrial (LA/RA) volumes and more pronounced RV systolic dysfunction. An EAT volume of >115.1 cm³ was associated with a 4.6-fold increase in the odds of detecting a preoperative TAPSE value < 1.7 cm (OR: 4.6 [95% CI: 1.2543; 16.7481]; p = 0.02). In the early postoperative period, patients with EAT volume > 115.1 cm³ exhibited larger RA dimensions and higher RV end-systolic volumes, as well as impaired RV–pulmonary artery coupling. At the one-year follow-up, patients with EAT volume > 115.1 cm³ exhibited larger indexed atrial volumes and basal RV dimensions. By the one-year follow-up, the group with EAT volume ≤ 115.1 cm³ was characterized by dynamic improvements, including a 10.7% increase in LV GLS (p = 0.02), a 33.6% reduction in the indexed LA volume (p = 0.004), a 28% reduction in the LV mass index (p = 0.003), and a 10.3% reduction in the LV end-diastolic dimension (p = 0.01). Furthermore, this group exhibited a 15% increase in LV stroke volume (p = 0.009), a 17.6% increase in TAPSE (p = 0.02), and a 6.5% increase in RV ejection fraction (p = 0.04) (3D Echo), none of which were observed in the group with EAT volume > 115.1 cm³. Patients with EAT volume ≥100.6 cm³ had more pronounced impairment of LV GLS before and one month after surgery compared with those with EAT < 100.6 cm³ (p = 0.046; p = 0.045). One month after surgery, worsening of RV GLS was observed specifically in the group with EAT ≥ 100.6 cm³ (p = 0.031). By the one-year follow-up, significant improvement in RV systolic function was observed only in the group with EAT volume < 100.6 cm³. Conclusions: The presence of excess epicardial fat (verified by cardiac CT) in cardiac surgery patients with acquired MV disease is associated with less favorable preoperative remodeling of both the left and right cardiac chambers and impaired reverse myocardial remodeling within one year post-surgery. Further studies in larger, independent cohorts are needed to confirm the prognostic and clinical relevance of the EAT cut-off in patients with mitral valve disease. Full article

Polyimide (PI) exhibits outstanding thermal stability and mechanical rigidity; however, their inherently rigid backbones lead to intrinsic brittleness, poor fracture toughness, and inferior impact resistance. Conversely, polyurea (PUA) features excellent elasticity, tunable soft–hard segment architectures, and a favorable balance of tensile strength and elongation at break. Herein, we systematically investigate the thermal and mechanical properties of 12 distinct PI, PUA, and PI-PUA copolymer systems via all-atom molecular dynamics simulations. Simulations demonstrate that rigid aromatic moieties significantly increase T_g and elastic modulus, while flexible hexamethylene diisocyanate (HDI) yields the highest elastic modulus via dense hydrogen-bond networks despite lowering T_g. Fluorine substitution effectively increases fractional free volume and moderately reduces T_g. Toughness is evaluated by K/G. System L with bulky phthalide side groups exhibits the highest K/G of 3.24, suggesting potential for improved plastic deformability as a preliminary screening indicator. In contrast, HDI-containing systems E and H show the lowest K/G ratios, as strong interchain hydrogen bonding severely restricts segmental slippage and induces brittle fracture. PI-PUA copolymerization proves to be an effective strategy to balance stiffness and toughness over a broad performance range. This work establishes structure–property correlations for PI-PUA systems, offering molecular-level insights for the rational design of advanced high-performance polymers, which require further experimental validation. Full article

Fiber-reinforced self-compacting concrete (FR-SCC) incorporating granite powder (GP), an expansive agent (EA), steel fibers (SFs), and polypropylene fibers (PPFs) was investigated for potential pre-cast tunnel-segment applications. Sixteen mixtures, covering GP replacement ratios of 0–18%, EA dosages of 0–8% by binder mass, and SF and PPF volume fractions of 0–0.75% and 0–0.15%, were tested in uniaxial compression on 100 mm × 100 mm × 300 mm prisms with acoustic emission (AE) monitoring. Within the tested range, 12% GP and 8% EA gave the most favorable binder composition. XRD and SEM analyses indicated that GP acted predominantly as an inert filler with no detectable portlandite consumption, while the expansive agent was associated with additional ettringite formation. At this composition, hybrid SF/PPFs increased the post-peak energy by a factor of 7.66 relative to the fiber-free mixture, mainly improving the post-peak rather than the pre-peak behavior. Among the Carreira–Chu, GB 50010, and modified Weibull formulations, the GB 50010 piecewise model best reproduced the full stress–strain curves and was used as the primary constitutive model. Two-variable regressions were established to separate the apparent effects of the SF and PPF volume fractions on the ascending- and descending-branch shape parameters, and a ductility-calibrated expression was developed for the descending-branch parameter. The Pearson coefficient between the descending-branch parameter and the AE characteristic strain was −0.904, while that between the AE characteristic strain and the macroscopic residual strain was +0.983. These results link constitutive modeling, AE damage evolution, and macroscopic post-peak ductility for FR-SCC within the tested range of mix proportions. Full article

Epoxy resin (EP) exhibits pronounced intrinsic brittleness arising from the highly crosslinked network formed after curing, thereby restricting its application in load-bearing structures. Although TiO₂ nanoparticles possess the potential for impact-strength improvement, they are highly prone to aggregation, which compromises stress-transfer efficiency within the composite. To overcome this challenge, a ball-milling strategy is adopted to anchor TiO₂ nanoparticles onto three-dimensional graphene oxide (3DGO), leading to the successful fabrication of a 3DGO@TiO₂ hybrid filler. At an ultralow loading of 0.03 wt%, the 3DGO@TiO₂ epoxy resin composite shows a 221.5% increase in impact strength to 19.55 kJ/m² and 33.53% and 32.34% increases in tensile and flexural strength to 64.32 MPa and 96.17 MPa, respectively, relative to neat EP. Morphological analyses indicate that the 3DGO spatial confinement reduces TiO₂ aggregate characteristic length by 55.1% from 1123 nm to 504 nm. Molecular dynamics simulations show that the hybrid filler decreases fractional free volume to 17.6%, induces denser matrix packing, and increases the calculated physical interfacial energy to 1023 kcal/mol, which is 2.2 times that of the pure TiO₂ epoxy resin system. This work confirms that 3DGO simultaneously optimizes nanofiller dispersion and physical confinement, offering a novel strategy for high-performance epoxy composites at ultralow loadings. Full article

Mixed-matrix membranes (MMMs) incorporating porous organic fillers into high-performance polyimides were developed to investigate the influence of free volume and molecular architecture on gas transport. Four structurally rigid, intrinsically porous fillers (TFAP-Trp, Is-Trp, TFAP-TPB, and Is-TPB) were incorporated into a range of polymer matrices (P84^®, Matrimid^®, Pi-DAPOH, Pi-DAROH, Pi-HABAc, Pi-DAM, and PIM-1), enabling the development of a matrix-independent methodology for estimating intrinsic filler permeabilities for five gases (He, O₂, N₂, CH₄, and CO₂). This comprehensive multi-matrix, multi-gas study reveals a strong correlation between filler fractional free volume (FFV), BET surface area, and gas permeability, with isatin-based fillers exhibiting particularly high CO₂ permeability. Filler incorporation generally resulted in substantial permeability enhancements (100–350%) while maintaining selectivity, often with only minor losses or even favorable improvements in CO₂/CH₄ and He/CH₄ separation performance. Several MMMs, particularly those based on Pi-DAPOH and Pi-DAROH polyimides, approached or exceeded the Robeson upper bound. Analysis of permeability as a function of gas kinetic diameter further elucidated clear structure–property relationships, confirming that filler-induced disruption of polymer chain packing and the creation of additional transport pathways are the primary factors governing separation performance. Overall, these findings demonstrate that rationally designed porous organic fillers provide a robust and broadly applicable strategy for mitigating the permeability–selectivity trade-off in polymer membranes and enhancing gas separation efficiency. Full article

This study investigates the mechanical performance of a pulsed laser butt-welded IN792 DS joint and its relationship to its microstructure by means of grid nanoindentation. A new ISE-free (rate-derived) hardness parameter (H_R) has been introduced to account for the local bulk elastoplastic behavior of the material in combination with the stable contribution of residual stress, thus overcoming the limitations of the current standard codes. It allows performance comparability between different welding experiments, materials, and joint configurations. It offers an alternate means to mechanically determine the HAZ width when microscopic and metallurgical methods fail to detect it. Moreover, the spectra of two independent indentation parameters have been utilized as an input within an iterative statistical deconvolution scheme to estimate the composition of the relevant phases present within the fused zone. While one parameter spectrum acted as a predictor in the first stage, the second one served as a corrector for the final estimation of the four detected phases, thereby self-validating the iteration procedure with 5% tolerance. The validity of phase estimation was first determined over the entire FZ and then at three levels of the weald seam (top, neck and bottom) for further validation. The results indicate that the γ-matrix and ultrafine fine/hard second phases in the fused zone amounted to 54% and 43% volume fractions, respectively. The associated deconvoluted mechanical performance, expressed in terms of E_IT, H_IT, and H_R, corresponded to approximately 209 ± 4.5, 6.3 ± 0.2, 4.4 ± 0.1 and 224 ± 7.0, 6.7 ± 0.1, and 4.6 ± 0.1 GPa, respectively. A correlation between the estimated phases and the local mechanical performance via the conventional indentation parameter (H_IT and E_IT) and the new H_R parameter in the three relevant regions of the fused zone was discussed while discerning the effect of cooling rate on precipitate size, heterogeneity, porosity, residual stresses, and grain orientation. Further validation studies on different sample geometries, materials and joint configurations are needed to confirm the generality of the proposed methodology. Full article

Ultrasonic inspection of welded steel components remains challenging due to weld-scale material gradients, local anisotropy, attenuation, and aperture limitations. These factors severely distort both the first-arrival wavefield and the late-arriving scattered wavefield. To address this, this study presents a numerical proof of concept for three-dimensional cross-weld virtual-array coda-wave tomography (VACWT). The “virtual array” utilizes a synthetic aperture created by re-indexing sequential source–receiver records from two opposing line scans into midpoint–angle–depth coordinates. This approach enables line-based data acquisition to achieve multi-angle volumetric coverage without requiring a two-dimensional matrix array. A parameterized welded-solid benchmark model was developed, incorporating effective longitudinal and shear wave velocities, attenuation, and out-of-plane tilt fields. Four defect scenarios were evaluated: a cylindrical void, a lack-of-fusion ribbon, a porosity cluster, and an interference case. For each source–receiver path, four observables were extracted from the synthetic records: first-arrival travel time perturbations, coda wave stretching, coda decorrelation, and late-window energy ratios. These observables were then coupled into a volumetric inverse problem to separate smooth slowness variations, distributed scattering strength, and compact defect occupancy. Under the current simulation conditions, VACWT achieved smaller recovered support volumes and higher volumetric overlap compared to the delay-and-sum total focusing method (DAS-TFM), background-corrected TFM, and reverse time migration (RTM). In the interference case, applying a fixed defect-free calibration threshold yielded a centroid error of 0.48 mm, a volumetric intersection over union (IoU) of 0.856, and a false-positive volume fraction of 0.0%. While these findings serve as benchmark results rather than generalized experimental validation, the study demonstrates that late scattered wave observables provide valuable constraints for volumetric support recovery in a controlled welded-solid model. Future experimental verification on welded steel specimens with known defects remains necessary. Full article