Search Results (1,240)

The study presents a comprehensive first-principles investigation of the structural, electronic, and magnetic properties of rocksalt scandium nitride (ScN) and its Cr- and Mn-doped derivatives using spin-polarized density-functional theory within the GGA + U (U_Cr = 3.5 eV, U_Mn = 2.7 eV) and HSE06 frameworks. Pristine ScN crystallizes in the cubic Fm$\bar{3}$m structure and exhibits narrow-gap semiconducting behavior, with an indirect band gap of 0.82 eV obtained from hybrid-functional calculations, in excellent agreement with reported theoretical values. Substitutional doping with Cr and Mn introduces localized 3d states near the Fermi level, driving a transition toward spin-polarized metallic or half-metallic behavior accompanied by robust ferromagnetism. Density-of-states and band-structure analyses reveal that magnetism and charge transport in the doped systems are dominated by exchange-split transition-metal 3d states hybridized with N-2p orbitals. Total energy calculations confirm ferromagnetic ground states for both Cr- and Mn-doped ScN, with Mn substitution yielding stronger exchange stabilization and higher magnetic moments. Magnetocrystalline anisotropy energies, evaluated using the force-theorem approach, are found to be negligibly small, indicating weak anisotropy consistent with the moderate spin–orbit coupling strength in ScN-based nitrides. Nevertheless, symmetry breaking around dopant sites gives rise to a finite Dzyaloshinskii–Moriya interaction, leading to weak spin canting and non-collinear magnetic tendencies. The interplay between magnetic exchange coupling, spin–orbit interaction, and local inversion symmetry breaking positions of Cr- and Mn-doped ScN as promising dilute magnetic semiconductors with tunable spin polarization and chiral magnetic interactions, offering a viable platform for nitride-based spintronic and magneto-electronic applications. Full article

The oil and gas industry is increasingly challenged by the global transition toward renewable energy systems aimed at reducing carbon emissions. Nevertheless, opportunities remain to mitigate the environmental impacts associated with ongoing oil and gas operations. One of the major environmental challenges in this sector is the extensive use and treatment of water. Membrane-based separation has emerged as an effective technology for oil–water separation due to its ability to overcome limitations associated with conventional treatment methods. This study aims to build a CFD model to investigates the influence of operational hydrodynamic conditions on membrane separation, including transmembrane pressure 202, 101, 50, 10 kPa, crossflow velocity 0.08 m/s, 0.116 m/s, 0.33 m/s, 0.66 m/s, and oil droplet diameter 1, 5, 10, 50, 100 µm, on membrane performance in addition to different oil concentrations 1%, 2%, 4%, 8% using Eulerian-Eulerian multiphase model. This is done by experimentally extracting the membrane water resistance, which is found to be 6.46 × 10¹⁰ (1/m) and using it as an input to the numerical model. The results indicate that permeate flux is primarily governed by transmembrane pressure, in agreement with Darcy’s law, while fouling development along the membrane length is mainly influenced by crossflow velocity and oil droplet size. Where it was found that for large droplets 100 µm and 50 µm the buoyancy forces were large enough to lift the oil droplets away from the membrane at velocities 0.08, 0.16 and 0.33 m/s while smaller droplets remained at the membrane surface In addition, backward diffusion, which has been emphasized in previous studies, was found to play a comparatively minor role in the present numerical analysis. Full article

This study aims to determine the current seismic resistance of two masonry minarets that were severely damaged during the 6 February 2023 Kahramanmaraş earthquakes, while also evaluating whether a model-updating approach based on experimental dynamic characteristics can reliably capture the actual seismic behavior and collapse mechanism of such structures under real earthquake conditions. The dynamic characteristics of the minarets were identified using Operational Modal Analysis (OMA) based on previous in-situ vibration measurements. These characteristics were used to calibrate finite element models through a model-updating process employing Multi-Criteria Decision-Making (MCDM) methods. The initial modal analyses revealed discrepancies of up to 13.7% in natural frequencies and 9.7% in mode shapes. After applying MCDM methods to a wide set of model variants, these differences were reduced to 2.0% and 9.2%, respectively, improving the agreement between numerical and experimental results. Once the most representative models were obtained, nonlinear seismic analyses were performed using actual ground motion records from the earthquake. The results included evaluations of peak displacements, base shear forces, and principal stresses. The concentration of principal stresses near the transition zone showed good qualitative agreement with the observed collapse locations, indicating a reasonable consistency between numerical results and observed damage patterns. These findings demonstrate the value of integrating OMA-based model updating with MCDM methods and support a data-driven framework for assessing the seismic performance of historical masonry structures. Full article

Peri-urban areas (PUAs), as transitional zones between urban and rural regions, play a critical role in supporting food systems and agricultural livelihoods, yet they are increasingly pressured by rapid urban expansion. Reliable spatial delineation of PUAs remains challenging, as administrative boundaries often fail to capture their functional and spatial heterogeneity. This study proposes a multi-dimensional, spatially explicit framework to delineate peri-urban areas using Indonesia as a case study. Eighteen indicators representing six analytical dimensions—land use/land cover, economic, demographic, infrastructural, spatial accessibility, and landscape structure—were derived from remote sensing and GIS-based data sources and integrated into a composite scoring system using equal-weighted and AHP-weighted approaches. The framework was applied to four major cities on Java Island (Jakarta, Surabaya, Bandung, and Yogyakarta) to generate continuous peri-urban probability surfaces, which were validated using expert surveys across 25 districts in the Jakarta and Bandung metropolitan areas. The results show that the framework effectively captures the spatial heterogeneity and gradients of peri-urban areas, with the equal-weighted approach exhibiting statistically significant agreement with expert assessments (Pearson’s r = 0.517, p = 0.008; Spearman’s ρ = 0.522, p = 0.008; Kendall’s τ = 0.387, p = 0.008), consistently outperforming the AHP-weighted model across all validation metrics. The proposed approach provides a transferable spatial mapping framework for monitoring peri-urban dynamics in rapidly urbanizing regions using remote sensing and GIS. Full article

Effective climate policy is central to sustainability transitions and to monitoring progress toward sustainable development, yet national climate policy ratings often differ in scope, indicator design, time coverage, and scoring logic, producing inconsistent country assessments. This creates a need for transparent tools that can compare, interpret, and contextualize existing indices rather than rely on any single metric. This paper develops an exploratory protocol for sustainability-oriented cross-index assessment of national climate policy effectiveness. We combine a structured comparative analysis and a SWOT-informed diagnostic synthesis of four representative approaches—the Climate Change Performance Index (CCPI), Climate Action Tracker (CAT), the Climate Laws, Institutions, and Measures Index (CLIMI), and the Climate Policy Measure Index (CPMI)—with a pilot inter-index concordance test using rank-based correlation analysis for a small country sample and a common reference year (2012). The pilot is intended as an illustrative methodological example rather than a generalizable statistical test. The results indicate strong alignment among broad, composite approaches (CCPI, CAT, CLIMI), while an instrument-focused metric (CPMI, centered on carbon pricing and fiscal signals) shows weaker consistency with outcome- and governance-oriented ratings. Building on these insights, we compile an integrated indicator set that links outcomes (GHG levels and trends), structural drivers (energy mix, efficiency), policy instruments (pricing, regulation, subsidies), governance capacity (legal and institutional strength), and enabling conditions (finance, public engagement, international cooperation). We also specify the operational steps of the proposed workflow, including index selection, temporal harmonization, ordinal encoding, concordance analysis, discrepancy diagnosis, indicator mapping, and provisional normalization, weighting, aggregation, and validation rules for future composite implementation. The protocol should therefore be understood as a sustainability-oriented decision support workflow for interpreting agreements and disagreements across existing indices and for supporting more balanced evaluation of low-carbon transitions; a fully aggregated composite index with large-sample validation remains a task for future research. Full article

Chain topology offers a chemistry-preserving route to tune block copolymer (BCP) self-assembly by modifying intrachain correlations and relaxation pathways without changing monomer interactions. Here, we perform a unit-matched comparison of four lamella-forming AB architectures reconstructed from an identical constitutive diblock unit ($N_0$): a linear diblock (DB), a linear multiblock (MB), a comb-like architecture (CB), and a star-like architecture (SB). Using dynamical density functional theory (DDFT), we quantify topology-dependent bulk ordering thresholds and show that architectural reconfiguration systematically stabilizes the ordered phase, reducing the order–disorder transition relative to DB (MB/CB/SB $\approx 0.793/0.762/0.752$ of the diblock value), in semi-quantitative agreement with random phase approximation (RPA) spinodal trends. We also compare topology-dependent directed self-assembly in a common trench geometry under matched reduced quench depth $\Delta \left(\chi N_0\right)=\chi N_0-{\left(\chi N_0\right)}_{\mathrm{ODT}}$, thereby isolating kinetic differences at comparable thermodynamic distance from bulk ordering. A Fourier-based alignment order parameter $\alpha \left(t\right)$ reveals sigmoidal alignment kinetics over decades in time and is well captured by a logistic form in $lnt$, enabling compact descriptors ($t_{50}$, $t_{90}$, and a steepness parameter k) that separate alignment onset from late-stage defect annihilation, while selective sidewalls robustly template sidewall-parallel lamellae across all topologies, the late-stage kinetics remain strongly connectivity dependent and can exhibit long-tailed completion associated with slow late-stage defect annihilation. These results demonstrate a dual role of topology in DSA: lowering the segregation strength required for bulk ordering while reshaping defect-mediated alignment pathways under confinement. Full article

Background: Current guidelines recommend lobectomy for tumors > 20 mm on CT, yet systematic CT–pathology size discordance may contribute to size-threshold–driven surgical decisions. We hypothesized that CT-based tumor diameter differs from pathological size near the 20 mm surgical boundary, potentially leading a proportion of patients to undergo more extensive resection than pathology would indicate under a size-only rule. Methods: We retrospectively analyzed 1096 patients undergoing thoracoscopic surgery for clinical stage I non-small cell lung cancer at a single center (2020–2024). CT–pathology agreement was assessed via Bland–Altman analysis. Optimal CT cut-off was identified using restricted cubic spline (RCS) modeling, internally validated with bootstrap resampling (B = 2000), and evaluated by decision curve analysis (DCA). Results: CT showed size-dependent bias: overestimation in small tumors (T1a: +4.21 mm) transitioning to underestimation in larger lesions (≥T2: −7.49 mm). At the 20 mm threshold, 15.8% of patients (n = 173) underwent lobectomy despite pathological size ≤ 20 mm (potential overtreatment). RCS modeling and bootstrap-optimized DCA identified 23 mm as the candidate revised threshold. Adopting CT > 23 mm would reclassify 108 patients from lobectomy to sublobar resection, reducing size-threshold–defined potential overtreatment by 51.4% while maintaining sensitivity for true ≥ T2 tumors. Conclusions: CT demonstrates size-dependent discordance with pathological size; this discordance likely reflects both CT measurement inaccuracy and specimen shrinkage after fixation, and the relative contributions cannot be separated from these data. A candidate 23 mm CT threshold, supported by DCA and internal bootstrap validation, could reduce size-threshold–defined potential overtreatment by 51% in this cohort. Prospective multicenter validation is required before clinical implementation. Full article

In recent years, the Mediterranean basin has been characterized as a climate change hotspot due to its rapid transition to warmer conditions and the strong agreement among most climate models predicting a significant decrease in precipitation by the end of the 21st century. These robust signals of climate change highlight the region’s high susceptibility to hydrometeorological extremes, such as droughts, which are expected to become more frequent, prolonged, and intense. In this context, the study focuses on Greece, where rising water scarcity threatens critical sectors such as food security, energy production, public health, and, more broadly, the resilience of ecosystems. Future drought conditions were assessed using the 12-month Standardized Precipitation Index (SPI-12) for 58 meteorological stations during 2071–2100, based on high-resolution regional climate simulations under RCP4.5 and RCP8.5. Spatial drought variability was examined using Principal Component Analysis, while drought severity and duration were quantified through Run Theory. The results indicate increasingly prolonged and severe droughts by the late 21st century, particularly in eastern Crete and southeastern Peloponnese, highlighting the urgent need for targeted adaptation measures. Full article

This study integrates phase change material (PCM) with semi-transparent photovoltaic (PV) glazing to develop a composite window providing thermal buffering and PV temperature regulation in summer. A PCM-PV double glazing window (PCM-PV-DGW) using paraffin PCM and CdTe semi-transparent PV glass was fabricated and evaluated through outdoor hot-box experiments and transient modeling in Qingdao, China. Four window types—DGW, PCM-DGW, PV-DGW, and PCM-PV-DGW—were tested under identical boundary conditions. The coupled system showed improved photothermal performance, achieving a daily average Solar Heat Gain Coefficient (SHGC) of 0.105, compared with 0.180 for PV-DGW without PCM filling, together with a temperature attenuation factor of 0.904 and a 35 min peak temperature delay. A two-dimensional transient heat transfer model incorporating radiative transfer through semi-transparent layers and an enthalpy-based phase change method was established and validated against measured inner-surface temperatures, showing good agreement (RMSE 1.54–1.80 °C). Parametric and sensitivity analyses indicate that PCM phase transition temperature is the dominant parameter (suggested 28–32 °C), while ~12 mm PCM thickness and 50% PV coverage offer a practical balance for the Qingdao summer scenario. The results provide preliminary guidance for PCM–PV window design under the investigated summer conditions. Full article

Changes in land use and land cover (LULC) are among the leading contributors to global environmental transformation. Analyzing these dynamics is essential for understanding historical land utilization patterns and identifying the key drivers behind such shifts. This research focuses on LULC changes in the Kunar region of eastern Afghanistan. To classify the LULC types, the study area was divided into nine major classes using the Support Vector Machine (SVM) algorithm, based on Landsat 07 Enhanced Thematic Mapper Plus (ETM+) data for 2004 and Landsat 8 Operational Land Imager (OLI) data for 2014 and 2024. Past and present changes were evaluated using ArcGIS 10.8, while future scenarios for 2034 and 2044 were simulated using the Land Change Modeler (LCM) embedded in the TerrSet platform, combined with the Cellular Automata–Markov Chain (CA-MC) model with 90% kappa agreement validation value. From 2004 to 2024, grassland expanded significantly from 68.93% (3406 km²) to 73.94% (3654 km²). Built-up areas grew from 0.59% (29.10 km²) in 2014 to 1.02% (50.39 km²) in 2024. Conversely, dense forest cover declined from 27.50% (1358.90 km²) to 22.96% (1134.75 km²), a decrease of 224.15 km². Barren land, after a temporary increase, also showed a net decline. Projections for 2034 and 2044 suggest a further reduction in forested areas to 1077 km², while grasslands and urbanized zones are expected to increase to 3690 km² and 60.63 km², respectively. These trends emphasize a swift transition in land use patterns, primarily driven by the conversion of forested and barren landscapes into settlements and grasslands. The findings underline the urgent need for implementing sustainable land management strategies to curb environmental degradation and ensure balanced land resource utilization in the future. Full article

This study employs effective field theory to investigate the magnetic properties of the Carbon-60 fullerene cage (C₆₀). The analysis shows that the magnetic behavior of the C60 molecule mirrors that of its sixty constituent carbon atoms, a phenomenon attributed to the molecule’s unique cage geometry and defined herein as the “identic magnetic effect” (IME). Furthermore, thermodynamic quantities, including magnetic susceptibility, specific heat, and internal energy, exhibit dual peaks at the coercive field points when the temperature is below the critical threshold (T < Tc). As the temperature exceeds this threshold (T > Tc), these peaks coalesce into a single maximum. These findings show good quantitative agreement with experimental phase transition characteristics, reflecting the magnetic behavior induced by the C₆₀ cage geometry. IME behavior can open the door to modeling and produce a new class of IME sensors (IMESs). Full article

Isosymmetric phase transitions driven by subtle hydrogen-bond rearrangements remain challenging for periodic density functional theory (DFT), particularly when energy differences between polymorphs are small. Resorcinol represents an interesting case in which the α and β polymorphs crystallize in the same space group and differ primarily in hydroxyl orientation and hydrogen-bond topology. In this work, the α–β phase transition was systematically investigated using periodic DFT calculations under ambient and elevated pressure. A broad set of exchange–correlation functionals combined with different dispersion corrections was benchmarked against experimental structural and energetic data. Dispersion-corrected methods were essential for reproducing lattice parameters and the pressure-induced inversion of stability. PBESOL with Tkatchenko–Scheffler dispersion provided the most consistent agreement with the experiment and was therefore used for phonon and ab initio molecular dynamics simulations. Phonon-derived thermodynamic analysis revealed a delicate enthalpy–entropy balance governing the transition, strongly affected by pressure. Dynamical simulations confirmed the instability of the α phase under compression, demonstrating the cooperative nature of this hydrogen-bond-driven isosymmetric transformation. Full article

Water vapor sorption in porous activated carbons (PACs) is governed by a complex interplay of pore architecture and surface functionality and often exhibits pronounced adsorption–desorption hysteresis. In this work, chestnut-shell-derived carbons were synthesized via a two-step thermal route—pyrolysis at 550 °C for 120 min followed by KOH activation at either 600 °C or 800 °C for 240 min—and evaluated using a dynamic vapor sorption analyzer to quantify water uptake, hysteresis, and temperature-dependent energetics. Both materials exhibit sigmoidal Type V isotherms, characteristic of cooperative water clustering on hydrophobic carbon surfaces with localized polar sites. At 25 °C, The PAC sample prepared at 800 °C shows a sharper uptake transition and higher total capacity (~0.45 g/g at 90% RH), compared to the broader, more gradual isotherm of the 600 °C sample (~0.17 g/g). Temperature-dependent isotherms collected between 25 °C and 45 °C were fit using the Dubinin–Serpinsky (DS-4) model, yielding good agreement (R² ≈ 0.997) and enabling mechanistic interpretation of primary site adsorption and cooperative cluster growth. Clausius–Clapeyron analysis of ln P versus 1/T at fixed loadings yielded isosteric heats of adsorption (ΔH) decreasing from approximately 45.4 kJ mol⁻¹ at low uptake (0.02 g g⁻¹) to ~43.8 kJ mol⁻¹ at intermediate loading, followed by a slight increase to ~44.2 kJ mol⁻¹ at higher coverage (0.35 g g⁻¹). This trend reflects the transition from strong adsorption at high-energy surface sites to cooperative water clustering and confinement effects within the pore network. These findings highlight the role of activation temperature in modulating sorption mechanisms and energetics, offering practical guidance for tuning biomass-derived carbons for atmospheric water harvesting applications. Full article

Two-dimensional (2D) materials, particularly MXenes and transition metal dichalcogenides (TMDs), have attracted intense interest as supercapacitor electrodes due to their high surface area and tunable electronic structure. However, large discrepancies persist between the quantum capacitance values predicted by density functional theory (DFT) calculations and experimentally measured gravimetric capacitances. In this review, we critically analyze DFT methodologies, surface models, normalization strategies, and electrochemical characterization protocols, and compile an extensive dataset of reported MXene and TMD systems to quantify the degree of experimental–theoretical agreement. We show that MXenes typically achieve less than 20% of their predicted capacitance because of restacking, surface terminations, and limited ion accessibility, whereas TMDs exhibit substantially better correspondence, often approaching or exceeding 70% of theoretical values. These results indicate that the theoretical capacitance predicted by DFT is primarily determined by the electronic structure of the material, which defines the upper limit of charge storage, whereas the experimentally achieved capacitance is largely controlled by morphological factors, surface chemistry, and electrode architecture that limit ion accessibility. Full article

In the marine environment, the suction caisson foundation (SCF) is often subjected to combined inclined and cyclic loading from wind and waves, which may significantly affect its ultimate bearing capacity. Under combined loading conditions, the evolution of ultimate bearing capacity is influenced by multiple factors, and the corresponding bearing capacity envelopes have become key issues that urgently need to be addressed. In this study, a series of model tests and numerical simulations were conducted considering the effects of load inclination angle, loading position, aspect ratio, soil undrained shear strength, and interface friction coefficient. The results show that under static loading conditions, as the loading depth increases, the load inclination angle corresponding to the maximum bearing capacity decreases from 45° to 0°. As the cyclic load ratio and static load ratio increase, cyclic loading significantly intensifies displacement accumulation and the degradation of ultimate bearing capacity. As the loading depth increases, the failure mechanism transitions from rotation-dominated to translation-dominated behavior. In addition, the ultimate bearing capacity increases monotonically with increasing aspect ratio, interface friction coefficient, and soil undrained shear strength. A normalized V–H bearing capacity envelope was established, which shows good agreement with the experimental and numerical results. By introducing a cyclic bearing capacity degradation coefficient, a modified envelope was proposed to describe the evolution of ultimate bearing capacity under cyclic loading conditions. The bearing capacity evolution patterns and envelope method proposed in this study provide a useful reference for the engineering design of SCF. Full article