Search Results (16,236)

The physical and mechanical performance of mortars incorporating waste marble powder (WMP) depends on powder characteristics and mixture design, whereas conditioning energy influences environmental impact. This study examined 0, 5, 10, and 15% cement replacement with Ecuadorian WMP at a water-to-binder ratio of 0.50 and a binder-to-fine-aggregate ratio of 1:2.1. WMP was characterized by scanning electron microscopy, image analysis, X-ray fluorescence, and X-ray diffraction. Mortar properties were evaluated at 28 days alongside a partial cradle-to-gate assessment. Number-based D₅₀ and D₉₀ were 3.145 and 8.097 µm. In the tested batches, 15% WMP reduced mean water absorption by immersion and open porosity by 33.6% and 30.1%, respectively. Mean compressive strength ranged from 3.66 to 6.38 MPa, but high within-batch variability at 5% and 10% replacement and one batch per formulation prevented establishment of a reproducible strength effect. Laboratory-scale conditioning increased global warming potential by 4.08–12.25% relative to the control. The 15% formulation warrants further investigation for non-structural rendering and plastering, subject to independent batches and additional performance and durability testing. Full article

The behavior of soil–structure interfaces under varying thermal conditions is crucial for the design and stability of geotechnical structures subjected to temperature fluctuations, such as energy piles and underground structures. This study investigates the impact of temperature variation and cycling on the shear strength of the concrete–reconstituted silty clay interface using a custom-designed direct shear apparatus equipped with a temperature control system. Three test series were considered: constant temperatures of 30, 40, 50, and 60 °C; single heating–cooling paths of 25–30–25, 25–40–25, and 25–50–25 °C; and one to three cycles between approximately 25 and 50 °C. Normal stresses of 100–400 kPa were applied, and shearing was conducted at 0.02 mm/min. The interface generally exhibited a strain-hardening response, and its terminal shear stress increased with normal stress but decreased with increasing temperature. In the constant-temperature series, heating from 30 to 60 °C produced a maximum measured reduction of 12.72% in interface shear stress. The apparent interface adhesion decreased from 17.09 to 9.38 kPa, a reduction of 45.11%, while the apparent interface friction angle decreased from 38.66° to 36.50°. Increasing the single-cycle temperature amplitude reduced the fitted apparent interface adhesion and friction angle by 21.65% and 3.05%, respectively. From one to three thermal cycles, these parameters decreased by 18.45% and 9.07%, respectively. The results indicate that temperature level, heating–cooling amplitude, and thermal cycling can modify the measured interface response. The findings highlight the need to consider representative thermal histories when characterizing interfaces for thermally active geotechnical systems. Full article

Background: Spatial frequency domain imaging (SFDI) is a non-contact, wide-field optical imaging technique that quantifies tissue absorption (μₐ) and reduced scattering coefficients (μ_s′). Conventional SFDI provides depth-averaged 2D maps. Methods: This study presents a simulation-based framework for depth-resolved optical property estimation over five depth layers, including discrete 3D inclusions. The framework also includes a comparison of two conditional GAN (cGAN) designs for synthetic data augmentation. Monte Carlo simulation generated 1000 heterogeneous tissue samples, with μₐ and μ_s′ varied independently. Two cGANs with identical architectures were trained. The first was a physics-guided (PG-cGAN), with six physics-based loss terms; the second was a data-driven (DD-cGAN) with no physics losses. Each cGAN generated 5000 synthetic samples. A multi-output U-Net was trained on each synthetic dataset separately and evaluated on the same held-out set of 200 real MCX samples to assess downstream optical property estimation accuracy. Results: Synthetic augmentation significantly outperformed the real-only baseline, with DD-cGAN reducing μₐ error by 47.7% and μ_s′ reducing error by 34.6%, while PG-cGAN reduced μₐ error by 43.2% and μ_s′ error by 33.5% (Exp4: μₐ R² = 0.9953, μ_s′ R² = 0.9328; Exp9: μₐ R² = 0.9957, μ_s′ R² = 0.9325; ΔR² < 0.002). Per-slice analysis showed that Exp 9 achieved lower μₐ in deep slices, whereas Exp 4 had advantages in superficial slices. The two synthetic datasets also demonstrated complementary strengths. DD-cGAN produced samples that are closer to the physics targets (DC–μ_s′ error: 4.9% vs. 28.4%), whereas the PG-cGAN achieved higher image fidelity (paired SSIM: 0.622 vs. 0.599). Both designs achieved equivalent cross-condition diversity (0.789 vs. 0.791). Independent validation on a different MCX dataset (500 samples, seed 2026) confirmed that the derived physics relationships were consistent within the simulated parameter range. Conclusions: Both cGANs designs demonstrate comparable downstream performance. DD-cGAN provides improved physical correlation fidelity, whereas PG-cGAN provides improved image fidelity. These comparisons have been demonstrated using in-distribution MCX test data. Clinical translation will require experimental validation on phantoms and ex vivo tissue samples. Full article

LGBTQ+ youth in Eswatini navigate identity and well-being within social environments shaped by cultural expectations, legal restrictions, family relationships, educational institutions, and community attitudes. Although existing scholarship documents stigma and exclusion affecting sexual and gender minorities, less is known about how young people themselves interpret these experiences and how intersecting identities shape both vulnerability and resilience. This study explored the lived experiences of LGBTQ+ youth aged 16–24 years in Eswatini, with particular attention to identity, acceptance and recognition, resilience, and the influence of legal and cultural norms. A qualitative narrative inquiry design was employed with 18 participants recruited purposively through LGBTQ+ community organisations and support networks, followed by snowball recruitment. Twelve participants were recruited through LGBTQ+ organisations and six through participant referrals. The sample comprised seven participants who self-identified as transgender men, six as transgender women, three as lesbian, and two as gay. Data were generated through six individual semi-structured interviews and two focus group discussions involving six participants each. Data were analysed using reflexive thematic analysis informed by narrative inquiry, while intersectionality theory guided interpretation of the interaction between gender identity, sexual orientation, age, family background, socioeconomic position, religion and spirituality, and broader cultural, legal, and institutional contexts. Three interconnected themes were developed: struggles for acceptance and recognition, resilience and personal strength, and the impact of legal and cultural norms. Participants described identity concealment, family and community rejection, school exclusion, and fear associated with legal and institutional environments. At the same time, they described self-acceptance, chosen family, friendship, community connection, education, storytelling, and future aspirations as important resources for navigating adversity. The findings show that LGBTQ+ youth should not be understood only through vulnerability; their accounts also demonstrate agency and adaptive capacity. The study contributes context-specific qualitative evidence from Eswatini and highlights the importance of youth-centred, culturally responsive approaches across schools, counselling services, community organisations, families, and policy environments. The study further demonstrates that support cannot be separated from the structural conditions in which young people live, because family, school, community, and legal contexts may simultaneously constrain identity expression while also providing opportunities for belonging and resilience. Full article

AA5083 Al-Mg alloy is widely applied in lightweight marine and transportation structures, yet thin-plate arc welding suffers from prominent out-of-plane deformation and coarse columnar-grain issues originating from concentrated arc heat input. This work adopted sinusoidal torch-oscillation-assisted CMT to conduct butt-welding experiments on 2 mm-thick AA5083-H112 sheets with ER5183 filler wire. Five oscillation amplitudes ranging from 0 mm to 4 mm were set to explore the coupled effects of oscillation amplitude on weld geometric features, three-dimensional base-plate deformation, weld-zone microstructural evolution, crystallographic texture and tensile-fracture behaviors. The results reveal that appropriate torch oscillation redistributes arc heat flux and introduces molten-pool stirring. It mitigates thin-plate out-of-plane deformation, refines grains, and promotes equiaxed-grain formation with a slight decrease in the measured texture intensity. The joint's comprehensive mechanical performance is highest at an oscillation amplitude of 2 mm among the tested conditions in this work: ultimate tensile strength, yield strength, and elongation attain 219.03 MPa, 112.14 MPa, and 18.45%, accompanied by typical ductile-dimple fracture features. Nevertheless, amplitudes exceeding 3 mm destabilize the molten pool and trigger pores and local lack-of-fusion defects, leading to sharp performance deterioration and brittle fracture. The competitive relationship among deformation relief, grain refinement, and defect generation determines the valid amplitude window. This study provides an experimental reference for high-quality CMT welding of thin-gauge 5083 aluminum alloy via torch-oscillation process regulation. Full article

Radon, a naturally occurring radioactive gas, is classified as a Group 1 carcinogen by the World Health Organization (WHO) and remains a significant environmental health hazard. Radon exposure is the second leading cause of lung cancer worldwide, and lung cancer remains the only health outcome firmly established to be caused by radon exposure. Possible associations with chronic obstructive pulmonary disease, hematological disorders, skin diseases, and other conditions remain under investigation. This review explores the broad spectrum of health risks associated with radon exposure, including its biological effects at histopathological, cellular, and molecular levels, with a focus on unique radiation effects such as the bystander effect and inverse dose-rate effect. Despite its harmful effects, radon has also been investigated for potential therapeutic effects under controlled exposure conditions, although the strength of clinical evidence varies across indications. Known as radon therapy, it has been investigated primarily for rheumatic and musculoskeletal disorders, while evidence for neurological disorders and cancer-related applications remains largely experimental or limited. The biological mechanisms of radon therapy, including its regulation of oxidative stress, immune modulation, and redox balance, are discussed. The effects of radon on human health, whether harmful or therapeutic, are highly dependent on factors such as dose, exposure duration, and individual susceptibility. This review concludes by highlighting key areas for future research to refine our understanding of both the risks and therapeutic applications of radon. Full article

Adhesively bonded carbon-fiber-reinforced polymer (CFRP) joints offer efficient load transfer and weight-saving potential in aerospace structures. The simple geometry of single-lap joints (SLJs) makes them useful for examining bond durability, although the effects of hygrothermal aging on their performance have not been sufficiently investigated. This research systematically integrates moisture absorption experiments, mechanical testing, finite element modeling (FEM), and deep neural network (DNN) modeling to provide a comprehensive analysis of moisture absorption behavior, strength degradation, and the evolution of failure modes within the adhesive layer. Initially, three types of adhesives were aged under various hygrothermal aging conditions to investigate their moisture absorption behavior and mechanical performance after aging. The tensile strength and modulus of the adhesives decreased linearly with increasing moisture uptake. In addition, hygrothermal aging tests were conducted on SLJs. Results demonstrated a significant reduction in joint shear strength during aging, accompanied by a transition in failure mode from cohesive to interfacial. Subsequently, a hygrothermally coupled FE model was developed using the experimental data and combined with a cohesive zone model to simulate joint strength evolution. The FE model achieved a calculation error within 5%. To address the high computational cost associated with finite element analysis of hygrothermal aging in SLJ structures and to enhance the physical interpretability of data-driven models, a novel prediction strategy was introduced. A three-stage serial neural network model was constructed using experimental and simulation data, with the quadratic stress criterion and power-law criterion embedded as physical constraints. Compared to unconstrained models, this physics-constrained neural network exhibited superior prediction accuracy and stability. The proposed method offers a valuable reference for the design and evaluation of the durability of CFRP bonded structures. Full article

Helical anchors represent a promising solution for anchor systems of floating offshore wind turbines, yet scour-induced changes to the seabed threaten anchor stability. The bearing capacity and failure mechanisms of helical anchors under such conditions have not been fully investigated. Finite element (FE) analyses examine scour geometry, anchor length, and soil heterogeneity (κ = kD/s_um, where k is the undrained strength gradient, D is the shaft diameter, and s_um is the surface strength). The results demonstrate that scour depth is the dominant factor governing bearing capacity, whereas scour width and slope angle have limited effects. Horizontal capacity is particularly sensitive to scour because the corresponding failure mechanism develops mainly within shallow soil. Increasing κ mitigates scour-induced capacity loss, with this effect being most pronounced as κ rises from 0 to 2, beyond which further increases yield diminishing benefit. Across different helical anchor embedment lengths, scour is shown to shift the critical embedment depth separating shallow and deep failure mechanisms, particularly under low soil heterogeneity. The effects of loading direction are further evaluated within the V-H loading space. Finally, predictive expressions are developed to capture the coupled effects of scour geometry, soil heterogeneity, and anchor length for engineering capacity assessment. Full article

High-power laser cleaning has been extensively adopted to remove organic coatings, but pulse duration, pulse energy, and overlap rate must be adjusted to limit residue and thermally affected surface modification. In this work, a 1000 W MOPA pulsed fiber laser was used to strip a 75 ± 5 μm thick iron-red epoxy primer from AH36 marine steel. Single-factor tests and an L9(3³) orthogonal design were evaluated using image-derived paint removal rate (PRR), surface roughness (Ra), SEM morphology, and energy-dispersive X-ray spectroscopy (EDS); every processing condition was repeated on five independently prepared coupons. Increasing pulse energy from 5.0 to 12.5 mJ raised the mean PRR from 79.01% to 99.67%, although the improvement above 7.5 mJ was marginal. At 70% overlap, PRR reached 99.12%, Fe was 77.7 wt.%, C was 8.1 wt.%, and Ra reached 4.196 μm, showing that high Fe exposure alone did not define the best surface state. Descriptive range values from the replicated L9 runs gave the apparent PRR order overlap rate > power > pulse duration; since the archived worksheet retained only run means, the small differences among the ranges cannot be tested against within-run error and are not treated as statistically significant. Run 2 (300 ns, 6.00 mJ at 100 kHz, and 60% overlap) was selected from the tested combinations as a multi-index engineering compromise rather than as a predicted optimum. It produced PRR = 99.90% and Ra = 1.308 μm. Pull-off testing used three dollies per recoated condition; the mean strength of the laser-cleaned condition was 5.20 MPa and failure was predominantly cohesive within the epoxy. Full article

Combining multiple industrial waste streams as alkali-activated precursors provides compositional complementarity but also creates complex interactions that cannot be explained by bulk chemistry or final performance alone. This review examines precursor compatibility through three coupled processes: dissolution, elemental competition, and phase selection. Precursor reactivity is interpreted hierarchically in terms of bulk composition, potentially reactive composition, and the composition actually dissolved under specific reaction conditions. In multi-source systems, asynchronous release of Ca, Si, Al, Mg, and associated anions continuously modifies pore-solution chemistry, saturation states, nucleation, and interfacial transport. Dissolution therefore becomes mutually coupled, while released species compete for incorporation into binding gels and secondary phases. Their temporal availability, transport, and structural accommodation ultimately govern phase selection and spatial heterogeneity. Because increased strength or heat release alone is not a unique signature of chemical coupling, precursor compatibility should be established by linking changes in precursor-specific reaction kinetics with effective elemental supply and partitioning, phase evolution, and macroscopic response. This mechanism-based perspective reframes precursor compatibility as a conditional compatibility window, and shifts multi-source alkali-activated materials design from empirical precursor proportioning toward coordination of reaction time windows, elemental supply, and targeted phase formation under specified activator chemistry, pH, temperature, precursor proportion, curing conditions, and reaction time. Future studies should quantify time-resolved elemental balances and phase-competition boundaries and integrate them with reaction–transport models to identify robust compatibility windows under realistic precursor variability. Full article

Using adaptive intelligence as a theoretical lens, the study investigates how L2 motivational selves are associated with AI-IDLE engagement through psychological capital (PsyCap) and L2 grit and whether these indirect associations vary with AI literacy among 1025 Chinese university EFL learners. The proposed model was tested using structural equation modeling (SEM). For the ideal L2 self, associations with engagement emerged both directly and indirectly through PsyCap and L2 grit, whereas the ought-to L2 self showed an indirect association through PsyCap and no direct association with engagement. Higher AI literacy corresponded to stronger associations of both PsyCap and L2 grit with engagement. The two motivational self-guides were therefore associated with engagement through different psychological pathways, with AI literacy related to variation in the strength of these pathways. From an adaptive intelligence perspective, this conditional pattern indicates that the relevance of PsyCap and L2 grit to AI-IDLE engagement varies with learners’ AI literacy. These findings extend the application of adaptive intelligence to informal human–AI learning. Full article

Mechanical recycling of post-consumer poly(ethylene terephthalate)/high-density polyethylene (PET/HDPE) streams is limited by immiscibility and processing-sensitive behavior. A nominal 30 wt% PET/70 wt% HDPE blend was evaluated using a 2 × 3 factorial matrix combining maximum extrusion setpoints (T_e: 235 and 260 °C) and maximum injection setpoints (T_inj: 200, 230, and 260 °C). Each processing combination was represented by one run from common bulk feedstocks. Tensile (n = 54) and flexural (n = 53) responses were compared using within-campaign specimen-level contrasts and descriptive multi-response scoring. The T_e= 260 °C/T_inj= 200 °C condition produced the highest observed strength–stiffness response, with tensile strength of 32.5 ± 2.23 MPa, flexural strength of 49.2 ± 6.35 MPa, and flexural modulus of 1550 ± 143 MPa. At T_inj= 200 °C, phase-agnostic SEM analysis showed finer fracture-surface texture after extrusion at 260 °C. Charpy impact followed a different trend, with T_e= 235 °C/T_inj= 200 °C giving the highest observed blend impact response. These results indicate distinct processing–performance relationships for static and impact behavior in the uncompatibilized post-consumer PET/HDPE blend and establish a baseline for further processing and compatibilization studies. Full article

Compressed air energy storage (CAES) is a promising large-scale energy storage technology, but its efficiency and safety depend critically on the sealing performance of underground caverns. From a building materials science perspective, a key challenge is to develop cement-based sealing materials that maintain low gas permeability and mechanical stability under coupled thermo-pressure cycles. However, the gas permeability evolution and microstructural mechanisms of sulphoaluminate cement-based airtight concrete under such conditions remain insufficiently understood. To address this problem, this study developed an airtight concrete for CAES cavern sealing layers, based on sulphoaluminate cement with fly ash, slag, basalt fiber, and chemical admixtures. Mechanical properties, gas permeability, and microscopic mechanisms were evaluated through uniaxial compression and tensile tests, gas permeability tests under different thermal-pressure cycles and pore pressure conditions, and SEM/DEM analysis. The material exhibits a compressive strength of 62.59 MPa and good airtightness. Under 60 °C cycling, Permeability remained on the order of 10⁻¹⁸ m², following the Klinkenberg gas slippage model. Microscopic analysis suggested a dense structure with limited visible pore connectivity. COMSOL Multiphysics preliminarily indicated that, under assumed design conditions (e.g., the Three Gorges Ulanqab project), the sealing layer remained in triaxial compression with an estimated gas leakage rate below 1%, demonstrating satisfactory sealing performance and structural stability within the investigated operational period. This study provides a theoretical basis and experimental support for sealing material design in CAES caverns. Full article

Bedding orientation affects coal strength and the interpretation of acoustic-emission (AE) signals, but detected activity and retrospective sequence descriptors have different monitoring meanings. Twelve coal specimens were tested under uniaxial compression, with three at each bedding angle of 0°, 30°, 60°, and 90°. Their mean peak stresses were 11.713 ± 1.412, 7.122 ± 1.064, 3.696 ± 0.667, and 10.357 ± 1.138 MPa, respectively (mean ± sample standard deviation). Detailed AE analysis remains limited to one specimen per orientation. For those four records, an event-index partition analysis at moment orders of −5 to 5 gives generalized-dimension ranges of 0.750, 0.552, 0.867, and 0.808 and spectrum widths of 0.925, 0.857, 1.088, and 0.987. Scale-range sensitivity, moment-range sensitivity, and temporal shuffling limit their interpretation to finite-scale heterogeneity. Independently estimated detrended-fluctuation slopes range from 0.597 to 0.775 and do not establish stationary long-range memory. Right-ended windows describe evolving AE structure without future observations, but no validated warning lead time is established. The mechanical results show an intermediate-angle strength minimum within the tested specimens; the AE observations support conditional mechanism hypotheses requiring replicate AE analysis and independent temporal and spatial validation. Full article

Background: The application of blood flow restriction (BFR) training extends beyond traditional resistance, with targeted use in cardiovascular conditioning, performance priming, and clinical applications relevant to athletic populations. Part 3, the final paper of this series, focuses on the application of blood flow restriction (BFR) during cardiovascular exercise (BFR-CV), ischemic preconditioning (IPC), and therapeutic applications, including the management of joint pain, tendinopathy, and bone health. Methods: A narrative review of research examining BFR applications for cardiovascular conditioning, performance priming, and clinical management was conducted using structured searches of PubMed/MEDLINE, SPORTDiscus, Scopus, and Web of Science, supplemented by targeted literature searching and reference-list screening through May 2026. Search terms encompassed BFR and occlusion training alongside cardiovascular and aerobic exercise, anaerobic and interval training, sprint and sport-specific conditioning, ischemic preconditioning and intra-conditioning, pain and tendinopathy, and bone health. Evidence from trained and athletic populations was prioritized, with relevant clinical and mechanistic studies included where athlete-specific evidence was limited or unavailable. Findings were synthesized narratively across conditioning, IPC/IIC, pain-management, and bone-health applications. Results: Low-intensity BFR-CV (40–50% VO_2max with 40–80% arterial occlusion pressure) may enhance aerobic capacity and muscular endurance in trained athletes while minimizing mechanical loading. Sport-specific BFR applications during soccer drills, basketball activities, and small-sided games have been associated with improvements in repeated-sprint ability and sport-specific endurance without impairing speed or power. IPC may produce small, context-dependent improvements (1–3%) in short-duration, high-intensity performance and may support recovery between repeated competitive bouts. Low-load BFR training (20–30% 1RM) may reduce joint and tendon pain while maintaining muscle strength and mass during rehabilitation. Evidence for bone health remains preliminary, with BFR showing potential to influence bone-turnover markers and preserve musculoskeletal function during periods of restricted osteogenic loading. Conclusions: BFR represents a versatile modality for conditioning, performance optimization, and athlete care when mechanical load or training time is constrained. Full article