Search Results (1,789)

In this work, the structural, electronic, charge-transfer, thermal, and magnetic properties of pristine and Fe-doped silicon carbide nanosheets (SiCNShs) were systematically investigated using spin-polarized density functional theory (DFT) within the Local Spin Density Approximation including Hubbard correction (LSDA + U). A 4 × 4 SiCNSh supercell containing 80 atoms was considered, where Fe atoms were substitutionally introduced at carbon sites to evaluate dopant-induced modifications in the nanosheet. Structural optimization, energy convergence, force minimization, and stress evolution analyses confirm that Fe incorporation preserves the structural integrity of the SiCNSh and leads to energetically stable configurations. The calculated defect formation energy (−7.44 eV/atom) demonstrates the thermodynamic feasibility of Fe substitution, while ab initio molecular dynamics (AIMD) simulations at 300 K verify the thermal stability of the energetically favorable Fe-doped configuration. Electronic-structure calculations reveal that pristine SiCNSh exhibits a nonmagnetic semiconducting nature with a band gap of approximately 2.4 eV, whereas Fe incorporation significantly modifies the electronic structure through pronounced Fe–3d/C–2p/Si–3p orbital hybridization. The band gap is reduced to approximately 1.1 eV for the single-Fe-doped system and further decreases to 0.53/0.51 eV (spin-up/spin-down) in the double-Fe configuration, while preserving semiconducting behavior. Spin-polarized band structure and density of states analyses demonstrate clear spin asymmetry near the Fermi level, indicating strong dopant-induced spin polarization and exchange interactions. Charge-density difference and Bader charge analyses reveal substantial dopant-induced charge redistribution characterized by electron depletion around Fe atoms, enhanced electron accumulation on neighboring carbon atoms, and partial charge neutralization of nearby Si atoms, resulting in a more localized covalent Si–C–Fe bonding environment. Mulliken spin population analysis further demonstrates robust ferromagnetic ordering, where the Fe dopant acts as the dominant magnetic center with strong induced spin polarization extending into neighboring Si and C atoms. Comparison between ferromagnetic (FM) and antiferromagnetic (AFM) configurations confirms that the 2Fe@C-doped SiCNSh stabilizes in a ferromagnetic ground state, exhibiting a favorable FM–AFM energy difference of 0.216 eV. Based on the mean-field approximation, the Curie temperature was estimated to be approximately 837 K, indicating strong magnetic stability significantly above room temperature. The present findings collectively demonstrate that Fe incorporation effectively tailors the electronic and magnetic properties of SiCNSh through band-gap engineering, spin-symmetry breaking, and stabilization of high-temperature ferromagnetism. These combined characteristics establish Fe-doped SiCNShs as promising candidates for spintronic devices, magnetic semiconductors, spin injectors, spin filters, and non-volatile magnetic memory applications. Full article

Monitoring dam deformation is critical for ensuring structural integrity and identifying long-term settlement trends. However, traditional InSAR techniques often face limitations in tropical environments due to severe temporal decorrelation. This study addresses these challenges at Jatiluhur Dam, Indonesia, by implementing an integrated framework using Sentinel-1 InSAR, in situ leveling, GNSS, and reservoir water-level data from 2019 to 2024. To overcome the observation bottlenecks, Tracy–Widom-guided PSI (TW-PSI) was employed and compared against SBAS and conventional PSI. The TW-PSI approach successfully increased on-structure measurement point density by approximately 40%, supporting a first-order ascending–descending decomposition into east–west and quasi-vertical components. The analysis reveals a persistent settlement bowl at the central crest (C7–C12), consistent with long-term leveling observations and supported by regional GNSS trend checking. While the 2022 Mw 5.6 Cianjur earthquake showed no statistically significant co-seismic crest deformation, a strong correlation (r = −0.709) was identified between crest deformation and reservoir water-level variations, suggesting an observational association between reservoir level and crest settlement tendency. Furthermore, the application of the Annual Structural Deformation Tolerance Ratio (ASDTR) identified specific priority monitoring zones. These findings demonstrate that the proposed integrated framework can support operational dam deformation monitoring by linking satellite-derived measurements with in situ observations and engineering-oriented interpretation. Full article

Full-physics reservoir simulation for CO₂ storage becomes computationally expensive when many operational schedules must be screened, motivating machine-learning (ML) surrogates that reduce simulation burden while preserving the essential physics-driven response. We propose an activity-based partitioning methodology that produces an interpretable applicability map, identifying regions where surrogate substitution is expected to be reliable and regions where highly active dynamics make it unsafe. In this work, we focus exclusively on the slow-varying region and develop proxy models for pressure and saturation time derivatives in that domain. The fast-varying region is intentionally excluded, and no fully coupled hybrid simulator is claimed at this stage. The partition is constructed from temporal changes in derivative signals and aggregated across multiple schedules to obtain a conservative, scenario-robust delineation. For slow cells, local stencil-based neural proxies leverage overlapping time windows and features describing the local state, schedule forcing, and injector influence. Because saturation derivatives in the slow region are strongly zero-inflated, with many cells remaining outside the advancing CO₂ plume for long periods, a two-stage strategy is adopted: first detecting whether meaningful change occurs and then predicting the derivative magnitude only when active, with additional smoothing to suppress near-zero artifacts. The framework also supports selective surrogate deployment over user-selected time windows. The objective is therefore to establish a conservative zone of applicability for derivative-based ML updates, rather than to demonstrate full simulator replacement or end-to-end coupled acceleration. In the case study, 5914 of the 8243 grid blocks evaluated by the proxy workflow were classified as slow-varying, corresponding to 71.7% of the evaluated proxy-analysis domain. For the blind schedule, full-rollout pressure reconstruction produced mean absolute errors of 5.34, 3.69, and 2.80 psi over early, middle, and late time-window groups, respectively. In a future coupled implementation using the same partition, these 5914 cells could be advanced by the ML proxy, while the remaining dynamically active or unsupported cells would remain under full-physics treatment. This would reduce the full-physics active-cell count from 9212 to 3298 in the future coupled setting, although direct wall-clock acceleration remains to be quantified after simulator integration. Full article

Graphite nozzles remain the dominant choice for small hybrid and solid rocket motors operating on laboratory and university budgets, owing to their low cost, ease of machining, and rapid turnaround during iterative design campaigns. These same programs, however, must contend with the fact that graphite erodes through coupled thermochemical and mechanical mechanisms when exposed to the oxidizing species generated by high-energy propellant combustion, and the resulting throat-area growth fundamentally alters the time histories of chamber pressure, thrust, and delivered specific impulse. This paper presents a nozzle-erosion reconstruction model that extracts the time-resolved throat area from coupled thrust and chamber-pressure measurements using the thrust coefficient relationship, scales the reconstructed area history against pre- and post-test throat measurements, identifies the onset and rate of erosion, and accounts for variable sensor lag between the thrust-stand and pressure-transducer signal chains. The model is exercised on two complementary sets of laboratory-scale GOX/ABS hybrid hot-fire data that together span roughly two orders of magnitude in total throat-area change and peak chamber pressures from 0.5 to 3.4 MPa: a controlled three-operating-point campaign conducted in support of the NASA Plume-Surface Interaction (PSI) program, and a set of higher-pressure firings from the laboratory development series in which the technique was matured. Reconstructed erosion-onset times, erosion rates, and total throat-diameter change are reported for each firing, the reconstruction accuracy is characterized as a function of erosion magnitude. A correlation of graphite erosion with chamber pressure is examined across the combined envelope. The results demonstrate the robustness of the reconstruction technique and provide a reusable framework for post-test reconstruction of transient nozzle geometry in rocket-engine ground testing. Full article

Dioecious plants often exhibit sex-specific physiological strategies that influence their response to environmental change. However, it is not well understood whether such dimorphism extends to the developmental trajectory of the photosynthetic apparatus during natural senescence. In this study, we compared the seasonal development and decline of photosystem II (PSII) function in naturally grown male and female Ginkgo biloba using non-destructive fast chlorophyll a fluorescence induction kinetics (OJIP) and JIP-test analysis. Sun-exposed, healthy leaves were sampled at approximately 15-day intervals from 18 July to 26 November 2024 [day of year, (DOY 188–332)]. The study monitored chlorophyll content and OJIP-derived parameters, and evaluated sex differences statistically (p < 0.05). Chlorophyll content began to decline after DOY 268 in both sexes, but decreased earlier and more rapidly in males. By DOY 332, male chlorophyll content fell to 1.37% of its level at DOY 268, whereas females retained 9.55%. OJIP fluorescence transient analysis revealed that ΔW_oj shifted from negative to positive values after DOY 268 in male plants, accompanied by a sustained increase in the relative variable fluorescence at the J step (V_j). This pattern indicates an earlier and more pronounced acceptor-side limitation of PSII in male plants, associated with accelerated accumulation of QA⁻ and restricted electron transfer from QA⁻ to QB and the plastoquinone (PQ) pool. In addition, male plants showed a clearer donor-side limitation, with a pronounced ΔW_ok response, suggesting reduced stability of the oxygen-evolving complex (OEC). In contrast, females maintained higher cross-section-based energy fluxes (TR₀/CS₀, ET₀/CS₀) and PSI-end acceptor reduction capacity (RE₀/CS₀), and exhibited a slower decline in integrated performance indices (PI abs, PI total, DF abs). Principal component analysis further suggested that male senescence trajectories were more tightly associated with changes in electron-transport efficiency, whereas females exhibited a more gradual adjustment in energy-flux allocation. Collectively, these results reveal pronounced sexual dimorphism in the PSII–PSI functional decline pathway during natural senescence in G. biloba and provide a physiological basis for understanding sex-specific variation in photosynthetic decline in this species, with potential relevance to broader studies of dioecious plants. Full article

The current research investigates the extraction efficiency of an emerging green technology, pressurized liquid extraction (PLE), compared to traditional stirring extraction (STE) in order to recover higher antioxidant capacity from three plant species of the Asteraceae family, namely Solidago virgaurea, Tussilago farfara, and Helichrysum stoechas. The optimal PLE conditions were achieved through a combined response surface methodology (RSM) approach. The resulting optimized PLE parameters (40% ethanol, 160 °C, 25 min, 1700 psi) were experimentally verified and directly contrasted with STE (40% ethanol, 80 °C, 60 min, 500 rpm). Despite having the same solvent polarity, the two methods showed significant variations in mass transfer kinetics and heat intensity. Across all species, PLE significantly boosted the ascorbic acid antioxidant capacity (p < 0.05), thereby showing enhanced recovery of compounds that contribute to the overall antioxidant capacity. STE generated noticeably increased total polyphenolic content and DPPH radical scavenging activity (p < 0.05), indicating that some phenolic subclasses might be susceptible to PLE at higher temperatures. Values for ferric-reducing antioxidant power were largely similar among approaches. Overall, PLE was shown to be highly effective in maximizing the total antioxidant capacity in shorter extraction times, while STE can better preserve specific polyphenolic fractions, as demonstrated through analysis of the optimal extracts by HPLC-DAD. The integration of experimental validation with chemometric modeling supports the reliability and practical applicability of the optimized PLE protocol. Full article

Hydrogen-compatible elastomeric seals are critical for the reliability and safety of high-pressure hydrogen infrastructure. However, hydrogen exposure can alter the mechanical response and surface condition of elastomeric materials through coupled transport–mechanical interactions. This study presents a comparative experimental and data-driven investigation of the pressure-dependent degradation behavior of ethylene propylene diene monomer (EPDM), nitrile butadiene rubber (NBR), and fluorocarbon elastomer (FKM) O-ring seals following 192 h exposure to hydrogen pressures ranging from 800 to 7000 psi at room temperature. Tensile testing was performed directly on complete O-ring geometries, and descriptor-based analysis was used to quantify peak-response behavior, energy absorption, stiffness evolution, and normalized deformation characteristics. Multivariate statistical methods, principal component analysis (PCA), clustering analysis, and Random Forest regression were applied to identify material-specific degradation patterns. NBR maintained the highest overall load-bearing capability and stiffness-related response across the investigated pressure range, whereas EPDM exhibited more compliant and non-monotonic deformation behavior. FKM showed the strongest pressure sensitivity, with substantial increases in force- and stiffness-related descriptors at elevated hydrogen pressures. Optical image analysis revealed pronounced increases in defect density and defect area fraction for NBR, while FKM exhibited comparatively stable surface-state behavior. PCA and clustering analyses identified distinct material-dependent degradation trajectories, and Random Forest regression achieved an R² value of 0.888 for energy-absorption prediction. The results demonstrate that hydrogen-induced degradation emerges through coupled interactions among stiffness evolution, deformation progression, energy absorption, and surface-state changes, providing a comparative framework for assessing elastomer performance in hydrogen environments. Full article

Background: Childhood malnutrition, manifesting as both underweight and obesity, is a global health concern with potential repercussions on neurodevelopment and metabolic health. Objective: To analyze the relationship between nutritional status, metabolic biomarkers, and cognitive performance in school-aged children. Methods: A cross-sectional study was conducted with 100 children between 6 and 12 years of age from a public elementary school in the municipality of Chiconcuac de Juárez, Mexico. Participants were categorized according to BMI: underweight (UW), normal weight (NW), overweight (OW), and obesity (OB). Anthropometric evaluation, serum biochemical markers, and three surrogate metabolic indices, namely the Triglyceride–Glucose (TyG), Triglyceride/high-density lipoprotein cholesterol (TG/HDL), and TyG-Body Mass Index (TyG-BMI), were calculated. Cognitive performance was assessed using the Wechsler Intelligence Scale for Children (WISC-IV). Results: The OB group children showed significantly higher levels of TG, TC and LDL-C, as well as elevated levels of TyG, TG/HDL and TyG-BMI indices (p < 0.05) and lower HDL-C concentration. While no significant differences were found in Full-Scale IQ (FSIQ), the NW group showed significantly higher performance in the PSI compared to all other groups outside the healthy weight range after FDR correction. Spearman’s correlation showed that surrogate metabolic indices exhibited exclusive negative correlations with the PSI in unadjusted bivariate models. Conclusions: The extremes of the nutritional status spectrum (UW and OB) are concurrently associated with early metabolic alterations and latent cardiovascular risk, while concurrently tracking with lower performance in selective fluid cognitive domains within unadjusted models. Furthermore, surrogate metabolic indices were shown to be valuable tools that co-vary with neurocognitive profiles. Full article

This paper presents a study of the structural and mechanical degradation of tungsten under steady-state mixed hydrogen–helium plasma (He/H₂). The experiments were carried out on the KAZ-PSI linear plasma simulator at a surface temperature of 1100 °C, while the helium fraction in the mixture was varied from 5% to 50%. Changes in surface morphology, roughness, phase composition, micromechanical response, and gas retention were analyzed using profilometry, scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS), X-ray diffraction (XRD), nanoindentation, and thermal desorption spectroscopy (TDS). The results show that increasing the helium fraction promotes the formation of a porous, defect-rich near-surface layer and modifies the gas-trapping behavior of tungsten. The surface roughness increases moderately from 0.031 μm for the initial polished state to 0.065 μm after exposure to a 50% He/50% H₂ plasma. EDS and XRD confirm that the observed degradation is not associated with detectable oxidation, carburization, or the formation of secondary crystalline phases. The TDS results indicate that helium-related vacancy complexes and gas-filled pores act as deep trapping sites for hydrogen. Therefore, the helium-modified near-surface layer should be considered as a trapping barrier that localizes hydrogen in the radiation-damaged layer rather than as a quantitatively proven diffusion barrier blocking hydrogen penetration into the bulk. Full article

Kimchi fermentation involves dynamic physicochemical and microbial changes; however, conventional monitoring methods are generally dependent on intermittent measurements, resulting in limitations in the real-time detection of abnormal fermentation. In this study, a Wireless Sensor Network (WSN)-based Fermentation Monitoring System (WFMS) and a Long Short-Term Memory (LSTM)-based Anomaly Detection System (LADS) were developed to continuously monitor internal pressure changes during kimchi fermentation. Kimchi samples were prepared under normal fermentation conditions (CON) and glucose-added conditions (GLU-6). Pressure data were collected at 10 min intervals using 15 psi and 30 psi pressure sensors connected to an Arduino Nano 33 IoT board and were transmitted to the ThingSpeak platform. During the fermentation period, pressure data were collected stably, while the external temperature was maintained at approximately 25 °C. Both CON and GLU-6 samples exhibited a rapid increase in internal pressure during the early fermentation stage, followed by a gradual decrease. However, relatively larger pressure fluctuations were observed in the middle and late fermentation stages of the GLU-6 samples. An LSTM autoencoder model trained using CON data established a reconstruction error-based threshold of 0.0025 and successfully detected anomalies in the GLU-6 samples. Anomalies were mainly identified during the initial fermentation stage and between fermentation days 2 and 4. These results demonstrate that pressure-based real-time monitoring combined with LSTM autoencoder analysis can be effectively applied for the non-destructive tracking of kimchi fermentation and the early detection of abnormal fermentation patterns. Full article

Cross-border blockchain investigations frequently face data isolation challenges where multiple jurisdictions may conduct parallel inquiries into the same suspicious entities, leading to operational conflicts and redundant efforts. This paper presents a purpose-built t-out-of-n watchlist-anchored private set intersection (PSI) protocol, adapting established threshold secret-sharing techniques for secure jurisdictional discovery, enabling agencies to identify overlapping investigative targets without prematurely disclosing sensitive case details. The methodology is built upon Shamir’s Secret Sharing (SSS) and polynomial interpolation over the $2^{127}-1$ Mersenne prime field. A deterministic dual-hash field mapping ensures statistical uniformity over the prime field. Experimental validation using the Elliptic++ dataset confirmed the system’s high efficiency. The protocol maintains linear communication complexity of $O(n·|{\mathcal{S}}_0\left|\right)$, where complexity scales with the watchlist size rather than the full participant dataset and remains stable under varying consensus requirements, where increasing the threshold t results in a marginal increase in total latency. Under the semi-honest adversarial model, the false-positive rate is cryptographically negligible at $2^{-127}$. The protocol achieves a hybrid security model wherein share privacy is information-theoretic under SSS, while field mapping and share authentication rely on standard computational assumptions. By integrating native source traceability, this framework provides a practical technological foundation for initiating formal Mutual Legal Assistance Treaty (MLAT) requests based on confidential matches identified across independent investigative workflows. Full article

Peeling behavior of soft materials is important in a wide range of applications, e.g., electronics, healthcare, etc. When applied on soft substrates, soft adhesives demonstrate unique mechanical behaviors compared to adhesives applied on rigid substrates. Adhesive properties can be conveniently measured by “peel testing”. The focus of this work is characterization of commercial glues on fabric substrates using commonly used peel tests. We investigate energy dissipation on textile substrates. For practical applications, we aim to develop a systematic approach for selecting adhesives for soft, flexible substrates. Here, we developed a multi-criteria framework for evaluating adhesives using data from peel tests. The criteria used here consider the shape and stability of the T-peel trace. The results of the multi-criteria evaluation were compared to traditionally used peel strength and fracture energy. Although E6000 produced the highest peel force ($1.82\pm 0.27 \mathrm{N} \mathrm{m}{\mathrm{m}}^{-1}$) and the largest apparent fracture energy, ${\mathrm{G}}_{\mathrm{c}}$ ($8673\pm 1545 \mathrm{J} {\mathrm{m}}^{-2}$), it showed large force oscillation ($\mathrm{S}\mathrm{S}\mathrm{A}=4.05\pm 0.83 \mathrm{N}$). Fabri-Fuse was selected based on its low oscillation ($\mathrm{S}\mathrm{S}\mathrm{A}=0.69\pm 0.29 \mathrm{N}$), lowest $\mathrm{C}\mathrm{o}{\mathrm{V}}_{{\mathrm{F}}_{\mathrm{c}\mathrm{i}}}$(4.0%), high peel stability index (PSI), and high displacement at break. Functional evaluation showed that Fabri-Fuse increased strain-to-electrical-failure to $34.95\pm 2.43\mathrm{\%},$ higher than direct printing on fabric or printing on E6000 (highest peel strength). These results suggest that metrics that consider the shape of the peel trace and inter-sample repeatability provide a useful alternative for selecting adhesives other than highest peel strength. Full article

Well control during drilling requires continuous assessment of bottom-hole pressure (BHP) relative to the pressure window bounded by formation and fracture pressures. This study presents a reduced-order, physics-guided digital-twin framework for well-control decision support, kick and loss risk assessment, and hybrid BHP prediction. The framework is intended as a computational decision-support prototype rather than a fully deployed, real-time, field-validated digital twin. It combines pressure-window calculations, dimensionless risk indices, bounded machine-learning correction, scenario-based event simulation, an interactive engineering dashboard, and 3D safety-envelope visualization. The machine-learning layer was trained on a predominantly augmented drilling dataset containing 909 cases, including nine field-related baseline records and 900 synthetically generated cases, and was used as a constrained correction mechanism rather than a replacement for the physics-based model. On the held-out test set, the BHP regression model achieved R² = 0.987, MAE = 108.6 psi, and RMSE = 215.7 psi, while the well-control status classifier achieved an accuracy of 98.35%. Scenario simulations reproduced representative kick-prone and loss-prone conditions and tracked the evolution of BHP, the Pressure Safety Index, the Kick Risk Index, and the Loss Risk Index. The results show that the proposed workflow can identify underbalanced states, quantify pressure margins, evaluate mud-weight sensitivity, and support visual interpretation of well-control risk. Further field validation, real-time data integration, uncertainty quantification, and robustness testing are required before operational deployment. Full article

This work evaluated the effect of enriched gas flood maturity and mobile water on transient foam behavior and oil recovery under high-pressure (2000 psi), moderate-temperature (38 °C) and salinity (20,000 ppm NaCl) conditions in high-permeability Bentheimer sandstone. A synthetic gas mixture containing relatively high contents of CO₂ (20%) and propane (26%) was used to simulate the enriched field gas. Screening of foaming surfactants including alpha olefin sulfonates and a betaine for good foamability and stability as well as low adsorption on the sandstone indicates that the alpha olefin sulfonate with a longer chain length was the best candidate for foaming the enriched gas in the presence of oil. Core flooding experiments conducted with this surfactant showed a strong impact of gas flood maturity and injection foam quality on both the transient foam behavior and oil displacement efficiency. Foam injection at residual oil saturation (about 14%) to a gas–brine flood exhibited robust foam propagation. The presence of mobile oil before foam injection due to the immaturity of the gas–brine flood (e.g., oil saturations above 50%) posed a detrimental effect on the rate of foam viscosity buildup. However, water injection during the pre-foam flood strongly supported foam generation even at relatively high oil saturations. A further evaluation of water contribution to enhancing foam propagation by adjusting foam quality showed that the water injection strategy before and during foam flooding should be optimized to improve both transient foam behavior and gas–oil contact for enhanced oil sweep efficiency. Full article

Target of rapamycin (TOR) is a conserved protein kinase that integrates nutrient and energy signals to control growth and metabolism, yet its proteome-level impact in microalgae remains poorly understood. Here, we conducted quantitative proteomics analysis of the unicellular red alga Cyanidioschyzon merolae under rapamycin-induced TOR inactivation to characterize global changes in protein abundance. TOR inhibition triggered widespread metabolic remodeling, including coordinated shifts in carbon and nitrogen allocation, and pronounced changes in protein synthesis, photosynthesis, and energy metabolism. Specifically, proteins associated with ribosome biogenesis and ribosomal subunits declined broadly, indicating impaired translation, alongside pronounced reductions in photosynthetic components, including PSI/PSII subunits and chlorophyll biosynthesis enzymes. In contrast, triacylglycerol (TAG) biosynthesis and starch metabolism were enhanced, indicating a shift towards carbon storage. Notably, a diacylglycerol acyltransferase (DGAT; CMQ199C) and a UDP-glucose pyrophosphorylase (UGP; CMS159C) were strongly induced (2.02-fold and 3.48-fold, respectively), identifying them as candidate targets for enhancing TAG and starch accumulation. Proteins associated with nitrogen assimilation were also upregulated, supporting TOR-dependent regulation of nitrogen metabolism at the protein level. Together, these results indicate that TOR orchestrates proteome-level reprogramming in C. merolae, coordinating growth, energy production, and carbon storage across interconnected metabolic pathways. Full article