Search Results (2,437)

Based on the thixotropic fluid theory, this paper presents a method for identifying soil liquefaction under earthquake with consideration of pore pressure thixotropy. By introducing the concept of “thixotropic-induced excess pore pressure”, the process of pore water pressure accumulation and structural state evolution of saturated sand under cyclic loading is described as a thixotropy behavior with the characteristics of internal structure destruction and reconstruction, and a soil vibration pore water pressure growth model based on thixotropic-induced excess pore pressure is established. The physical meaning of the model parameters is discussed, and the method to determine the parameters is given. The proposed method achieves an overall success rate of 83.6% when applied to a global database of 335 well-documented seismic case histories. Specifically, it correctly identifies 86% of the liquefied sites and 77% of the non-liquefied sites. In a direct quantitative comparison with the conventional NCEER simplified method on the same database, the TEPP model yields a higher area under the ROC curve (AUC: 0.793 vs. 0.759) and a higher overall accuracy (83.6% vs. 79.1%). The improvement in accuracy is statistically significant (McNemar test, p= 0.048). A systematic liquefaction discrimination process is proposed, which provides a new theoretical basis and practical tool for seismic liquefaction assessment. Full article

Laser-induced graphene (LIG) enables rapid conversion of polymer substrates into conductive carbon materials. In this study, nitrogen-containing carbon nanomaterials were fabricated on polyetherimide (PEI) substrates using empirical screening of two specific process points. The resulting materials were characterized using scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy to correlate structural features with electron-transfer behavior. Raman and XPS analyses showed different structure and morphology depending on irradiation regime. The carbon materials with a higher sp³ fraction (≈55–59%), larger in-plane crystallite size (L_a up to 8.0 nm), and pronounced π–π* shake-up satellites indicated enhanced graphitic ordering when a shorter nanosecond laser was used. These structural differences resulted in substantially lower charge-transfer resistance (0.53–0.79 kΩ·cm³) and larger electroactive surface areas for the porous electrodes compared with foam structured carbon nanomaterials. The results show that, under the selected fabrication conditions, variations in laser processing parameters correspond to differences in graphitic ordering and electron-transfer properties in PEI-derived laser-induced carbon materials. Full article

Metal–organic frameworks (MOFs) show great potential for post-combustion carbon capture, yet their practical application is often constrained by challenges such as powder handling difficulties, limited structural stability during shaping processes, and performance degradation under high-humidity conditions. In this study, Mg-gallate was structured into millimeter-sized Mg-gallate/CA composite beads via the ionotropic gelation method, and then a hydrophobic layer of vinyltrimethoxysilane (VTMS) was constructed on the bead surface by chemical vapor deposition. The synthesized Mg-gallate/CA and V-Mg-gallate/CA are characterized by XRD, FT-IR, and other techniques, and their CO₂ adsorption behavior, adsorption–desorption kinetics, breakthrough performance, and cyclic stability are systematically evaluated. At 298 K and 0.1 bar, the CO₂ adsorption capacity of Mg-gallate/CA reached 94.2% of that of Mg-gallate powder. The microporous–microporous hierarchical structure constructed by the ionotropic gelation method improved the CO₂ capture efficiency of the composite beads by 16.7% at 0.1 bar. V-Mg-gallate/CA maintained a high dynamic CO₂ adsorption capacity of 2.87 mmol/g for a 10 vol.% CO₂/90 vol.% N₂ gas mixture at 298 K under 80% RH, corresponding to 2.04 times the capacity of Mg-gallate/CA, and retained 98.8% of its initial adsorption capacity at 0.1 bar after 10 cycles. Combining ionotropic gelation shaping with surface hydrophobic modification represents an effective strategy for developing MOF-based adsorbents suitable for post-combustion CO₂ capture. Full article

The growing emphasis on environmental sustainability and the need for advanced manufacturing methods have accelerated progress in material processing. Aluminum powder metallurgy (APM) is particularly promising due to aluminum’s low density, high strength-to-weight ratio, and the inherent benefits of the powder metallurgy (PM) process. However, the corrosion resistance of sintered aluminum components remains a significant concern. In this study, shot peening (SP) was employed as a surface modification technique to improve the corrosion behavior of Alumix 321 PM alloy. Samples of the as-sintered and shot-peened Alumix 321 PM alloy, together with the wrought alloy counterpart AA6061, were characterized using non-contact optical profilometry, optical microscopy (OM), and scanning electron microscopy (SEM). Corrosion performance was evaluated in 3.5 wt.% NaCl solution using Tafel extrapolation (TE), cyclic polarization (CP), stair step polarization (SSP), and electrochemical impedance spectroscopy (EIS). The results revealed that shot peening increased surface roughness and significantly reduced the corrosion rate from 0.079 mmpy to 0.004 mmpy for the unpeened and peened samples, respectively. While pitting was the dominant corrosion mechanism in the wrought alloy, the PM alloy exhibited a combination of pitting, crevice, and intergranular corrosion. These findings highlight the potential of SP in enhancing the durability of aluminum-based PM components, offering valuable insights for industrial applications. Full article

The stability and functionality of offshore wind energy systems depend critically on how offshore platforms interact with the geotechnical features of the seabed. This review describes developments in five areas: (i) offshore geotechnical site investigation and strength assessment; (ii) seabed geohazard causes and deep-water mooring challenges; (iii) frameworks for seabed modeling; (iv) sediment behavior influencing anchor and mooring performance; and (v) selection of anchors based on their interactions with various soils. The review emphasizes developments in seabed assessment and modeling using field, lab, and numerical methods. It discusses how the new advances in analytical and simulation frameworks have enhanced our knowledge of anchor–mooring responses, cyclic loading behaviors, and soil–structure interactions under changing seabed conditions. The key findings reveal that: (1) cyclic loadings considerably change anchor holding capacity and evolution of seabed trenching, yet most existing design methods still use quasi-static loads; (2) site-specific data from integrated geophysical–geotechnical surveys are vital to reduce uncertainty in anchor penetration and the frictional resistance of chains; (3) geohazards, such as shallow gas, marine landslides, and seabed erosion, pose under-recognized risks to long-term anchor reliability. The lack of knowledge on the coupled, long-term evolution of the seabed–anchor–mooring line system is identified as another gap in the literature. Major gaps exist in validating the life cycle of anchor performance under real-scale storm–wave sequences for offshore geotechnical risk management in layered soils. At the end of the discussion, the current study also highlights the need for flexible, data-driven frameworks that integrate geotechnical, hydrodynamic, and structural analyses in a coupled framework to improve reliability in next-generation offshore wind energy systems. Full article

This study evaluated the influence of scan rate (4.23 mm/s [S10] and 6.35 mm/s [S15]) on the localized corrosion and tribocorrosion behavior of a laser engineered net shaping (LENS)-produced stainless steel 316L (SS316L) in a phosphate-buffered saline (PBS) solution. Electrochemical impedance spectroscopy (EIS) was performed by applying an AC signal from 10⁵ to 10⁻² Hz and cyclic potentiodynamic polarization (CPP) was performed by sweeping from −150 mV to +1.5 V (vs. open circuit potential) and back to characterize passivation and pitting susceptibility. Potentiostatic tribocorrosion tests were conducted using a reciprocating tribometer integrated with a potentiostat to probe material response in passive and cathodic regimes. S15 exhibited manufacturing-related defects that served as preferential pit initiation sites, with pits in both S10 and S15 showing evidence of cell-interior dissolution. Electrochemical results indicated that the charge transfer resistance was reduced by 66% for S15 and that the repassivation potential decreased by 35% compared to S10. Under tribocorrosion, material degradation was dominated by mechanical wear for both samples. However, sliding significantly accelerated electrochemical dissolution in S15, with the corrosion rate affected by wear (V_c-w) increasing by 46.8%. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) of wear scars revealed plastic deformation, abrasive grooves, and bio-tribofilm formation composed primarily of phosphates. Micro-pits associated with processing defects were observed exclusively in S15. Overall, lower scan rate processing (S10) produced a more defect-resistant microstructure with improved resistance to localized corrosion and tribocorrosion in PBS. Full article

Obesity resulting from melanocortin-4 receptor (MC4R) dysfunction is characterized by combined metabolic dysregulation and maladaptive reward-related behaviors that limit the durability of existing therapies. The endocannabinoid system is a central regulator of appetite, lipid metabolism, and reward processing; however, first-generation cannabinoid receptor 1 (CB1) antagonists were limited by adverse neuropsychiatric effects. SKNY-1 is an orally active tetrahydrocannabivarin (THCV) analog designed to engage pathway-biased CB1 signaling, modulate cannabinoid receptor 2 (CB2), and selectively inhibit monoamine oxidase B (MAO-B), with the objective of addressing both metabolic and behavioral components of obesity while minimizing central nervous system liability through biased CB1 signaling, CB2 modulation, and potential complementary MAO-B inhibition. Here, we integrated in vitro pharmacological profiling of SKNY-1 with in vivo evaluation in an adult mc4r(G894C) zebrafish model exhibiting obesity-associated metabolic and reward-related phenotypes. In vitro, SKNY-1 displayed low-potency modulation of CB1 cyclic AMP signaling (EC₅₀ ~30 µM) but more potent antagonism of the CB1 β-arrestin pathway (IC₅₀ ~6 µM), consistent with differential CB1 pathway modulation. SKNY-1 acted as a CB2 partial agonist (EC₅₀ ~0.1 µM), with antagonist activity emerging at higher concentrations, and selectively inhibited MAO-B at low affinity with no activity against MAO-A. In vivo, mc4r(G894C) zebrafish mutants exhibited dyslipidemia, hepatic triglyceride accumulation, altered appetite-regulatory gene expression, increased metabolic rate, and enhanced compulsive high-calorie feeding and nicotine-seeking behaviors. Oral administration of SKNY-1 for six days produced dose-dependent effects. Both doses normalized total cholesterol and low-density lipoprotein levels and reduced hepatic triglycerides toward wild-type values without affecting circulating triglycerides. The higher dose (200 ng per fish per day) induced significant body weight reduction while preserving body density and attenuated reward-associated feeding and nicotine-seeking behaviors. The lower dose (20 ng per fish per day) more effectively normalized the leptin a-to-ghrelin expression ratio. Collectively, these findings demonstrate that SKNY-1 engages integrated endocannabinoid and potential dopaminergic mechanisms to improve metabolic parameters and attenuate maladaptive reward-related behaviors in an MC4R-deficient vertebrate model, supporting its further translational investigation for obesity complicated by compulsive eating and substance-seeking behaviors. Full article

Rockfall events are significant natural hazards on fractured rock cliffs, often driven by environmental forcing, including thermal variations that induce stress and fatigue in rocks. This study presents the first application of Ground-Based Interferometric Synthetic Aperture Radar (GB-InSAR) for high-resolution monitoring of sub-millimeter thermally induced displacements on a rock slope. An eight-day pilot experiment conducted at the La Cornalle molasse cliff (Vaud, Switzerland) revealed cyclic displacement signals with a clear 24 h periodicity, identified through Fourier and wavelet analyses, with a mean amplitude of 5 × 10⁻⁴ m. Simultaneously, infrared thermography (IRT) and a weather station recorded rock surface and air temperature variations, allowing a first estimation of the time lag between thermal forcing and mechanical response, with delays of 1–8 h relative to air temperature and 1–6 h relative to solar radiation. An analytical deformation model based on thermal diffusion predicts a daily displacement amplitude of 4.2 × 10⁻⁵ m, highlighting a significant difference with GB-InSAR observations and emphasizing the influence of structural complexity and thermo-hydro-mechanical processes in rock slopes. These results demonstrate the capability of combined high-resolution remote sensing techniques to quantify thermo-mechanical behavior in rock masses and provide a methodological framework for future investigations of rockfall-prone slopes. Full article

Hydrogen transport under high-pressure conditions poses significant challenges for pipeline materials and structural design. Existing studies on PA12-based systems are primarily limited to material-level characterization, with insufficient validation at the pipeline scale. To address this gap, this study presents the design and system-level experimental validation of an all-thermoplastic composite hydrogen pipeline. A full-scale DN50 pipeline, consisting of a PA12 liner and a ±54° filament-wound carbon fiber-reinforced layer, was fabricated and tested under hydrogen pressures up to 10 MPa, including long-term exposure and cyclic loading. The results indicate stable deformation behavior and low hydrogen permeation (~10⁻¹⁴ mol·m/(m²·s·Pa)) within the investigated pressure range, with a burst pressure exceeding 60 MPa. A transition from stable to accelerated deformation was identified at elevated pressure, indicating a structural operating limit. Post-test observations reveal that interlaminar damage, rather than primary interface failure, governs long-term degradation. Based on these findings, a design framework integrating stress-based, deformation-based, and damage-based criteria is proposed. This work extends PA12-based hydrogen pipeline research from material-level understanding to system-level validation and provides practical guidance for structural design and performance evaluation. Full article

An integrated rebar box connection is proposed for the horizontal joints of fully prefabricated composite walls to simplify joint detailing and reduce on-site wet construction. Experimental tests and numerical analyses were conducted to evaluate the behavior of this connection. The results show that both specimens exhibited shear-dominated failure. The box connection and horizontal joint did not experience obvious fracture or pull-out failure, although local cover spalling, mortar crushing, and connector deformation were observed, suggesting effective force transfer between the upper and lower wall panels under the tested conditions. Compared with the cyclically loaded specimen, the monotonically loaded specimen exhibited higher peak load and larger deformation capacity under monotonic loading, whereas the initial stiffness was similar. The numerical results agree reasonably well with the experimental responses. The parametric finite element analyses indicate that increasing the integrated rebar diameter, the longitudinal reinforcement ratio in the rib columns, the concrete grid strength, and the axial compression ratio improves the load-carrying capacity of the wall, although a higher axial compression ratio reduces ductility. The proposed connection shows promising potential for use in the horizontal joints of fully prefabricated composite walls, and further studies with additional specimens and comparative connection details are warranted. Full article

Within the framework of elastoplastic theory, this study develops and improves a fractional cyclic constitutive model capable of describing rate-dependent ratcheting behavior by defining the ratcheting parameter as a function of the cumulative plastic strain rate and describing the plastic strain rate and back stress in fractional-order forms. Additionally, a brief introduction is provided on the numerical implementation process and parameter determination method of this model. The newly improved fractional-order model was subsequently employed to simulate and predict the cyclic deformation of the cyclically softening material, EA4T axle steel. The following conclusions can be drawn: owing to the incorporation of fractional calculus, the newly improved model can predict both the monotonic tensile curves and the cyclic softening behavior of materials under different strain rates—capabilities that are not achievable with conventional elastic–plastic cyclic constitutive models. By defining the ratcheting parameter as a function of the cumulative plastic strain rate, the improved fractional model can reasonably predict the evolution laws of both uniaxial and non-proportional multiaxial ratcheting. By describing the evolution of plastic strain rate and back stress in fractional-order forms, the newly improved fractional model can provide a relatively accurate prediction of the rate-dependent uniaxial and multiaxial ratcheting behaviors. Full article

Structural health monitoring (SHM) of composite structures using surface strain fields measured by digital image correlation (DIC) has been widely demonstrated; however, accurate damage quantification remains challenging. This study proposes a hybrid framework integrating finite element (FE) modeling, machine learning (ML), and peridynamics (PD). A CFRP specimen with a notch was subjected to cyclic loading, and damage evolution was monitored using DIC and validated by ultrasound measurements. A validated FE model generated synthetic strain-field datasets for ML training, enabling defect detection and quantitative characterization directly from surface strains. The trained models achieved high accuracy, including perfect notch detection and low prediction errors. A calibrated PD model captured internal damage evolution and fatigue behavior. The combined DIC–ML–PD approach enables accurate, non-contact damage identification and prognosis, supporting physics-informed digital twins for composite structures. Full article

In various countries, the shear-strength design formulas for reinforced concrete beam–column joints are primarily constructed based on concrete strength, and the influence of the main bars of the beam is not explicitly reflected in these expressions. To address this limitation, this study examines the shear behavior of the joint, focusing particularly on the amount and arrangement of the main bars of the beam passing through the joint. Four beam–column joint specimens were tested under cyclic loading. The main variables of the specimens were the amount and arrangement of the main bars of the beam. The detailed strain measurements were conducted to clarify the development of bond deterioration along the main bars and the associated internal force transfer mechanisms. The experimental observations revealed significant tension-shift phenomena and progressive bond deterioration in the compression-side main bars. Within the scope of the present test series, variations in the amount and arrangement of the main bars of the beam did not significantly affect the maximum applied load. However, the indirectly evaluated joint shear force was higher in specimens with two layers in the main beam bars. Force equilibrium using force components obtained by measured strain produced even larger values at greater drift angles, indicating that joint shear assessment depends strongly on the evaluation basis. A mechanics-based diagonal strut model incorporating the internal compression field provided improved agreement with experimental results, confirming its applicability for practical design. Full article

Reversion of amino acid mutations in structural proteins is common in viral evolution. SARS-CoV-2 provides an unprecedented opportunity for ecological studies, thanks to the abundance of available whole genome sequences. YoyoMut allows regular scanning of open SARS-CoV-2 data, reporting on all cyclic and reverting mutations within all proteins (including Spike), with fine-grained trend visualization distinguishing non-mutated from mutated positions (either fixated or cyclically reversed). In the whole CoVSpectrum database, order of 100 reverting and 50 fixated mutations were identified on Spike. Classification is determined using alternative algorithms (based on threshold or slope inversion); finally, a 3D-protein structure allows us to identify spatial clustering of adjacent mutated positions. Systematic, automated monitoring of these behaviors aids immunologists and structuralists in their manual curation. By generating informative reports, our tool supports daily activities that have practical implications for vaccine and therapeutic anti-Spike monoclonal antibody design: prioritizing analysis of cyclic mutation and reversion models could help avoid the recent failures in their development and inform future strategies. Full article

Near-fault earthquakes generate pulse-type ground motions that impose concentrated displacement demands on RC members, often leading to rapid degradation in stiffness and localized damage to negative-moment regions of T-beams. Although polymer-modified mortar (PMM) overlays with embedded reinforcement have demonstrated improved behavior under monotonic and cyclic loading, their response under seismic inputs with different characteristics remains insufficiently clarified. This study presents a parametric numerical investigation of RC T-beams strengthened with PMM overlays and embedded D13 and D16 steel bars and subjected to representative near- and far-field earthquake excitations. A three-dimensional nonlinear finite element model was developed and qualitatively validated against previously reported monotonic and reversed cyclic experimental results, with close agreement in the strength development and failure characteristics. The validated model was subsequently used in nonlinear time-history analyses. Under near-fault excitation, strengthening increased the peak load capacity by 52.40% (D13) and 73.30% (D16) relative to the control beam. For far-field motion, capacity gains of 53.77% and 65.85% were obtained, respectively. Near-fault input created pronounced localization in the compression zone, whereas far-field excitation resulted in more distributed cyclic deterioration. PMM strengthening substantially enhanced the flexural resistance and crack control, underscoring the importance of explicitly considering ground-motion type in performance-based seismic retrofit design. Full article