Search Results (1,292)

Integrated water resources management uses decision-making and planning techniques in developing long-term strategies to ensure the sustainability of water resources and the resulting water security of future generations. Policy formulation through such integrated planning interlinks with indicators serving as an information channel to decision-makers. The present effort aims to develop a specific methodology using technical, environmental, and social indicators, formulating composite indices to identify vulnerability to changing water conditions. Thus, a set of indices developed through a multiyear research effort in Latin America, namely Drought Vulnerability Index (DVI), Water Stress Vulnerability Index (WSTVI), Water Scarcity Vulnerability Index (WSCVI), and Water Changing Conditions Vulnerability Index (WCCVI). Time series analysis covered the years 1991–2020, whereas the reference period was 1961–2020. Climate and water resources information is mainly obtained from ERA5-Land reanalysis; social, economic, infrastructure, and institutional data derived from harmonized sources (COROADO Project-EU, FAO, The World Bank, WHO/UNICEF JMP). Statistical tests and Principal Component Analysis (PCA) identified the indicators included in the equations for each index. Expert knowledge played an important role in the development as data were collected according to known local specificities and global trends, as well as scientific criteria and methodological rigor regarding the proposed new indices. Finally, application of such a framework for spatially explicit analysis indicated higher levels of vulnerability to changing water conditions in the northern part of Mexico, the Andes, Bolivia, Paraguay, and Central America, and lower levels in Chile, Brazil, Uruguay, and Argentina. This application demonstrates that the produced composite indices may be implemented with matching success all over Latin America and, therefore, in diversified natural, technical, environmental, social and economic conditions. Full article

Heart failure with reduced ejection fraction (HFrEF) is increasingly recognized as a systemic metabolic disorder. The aim of this study was to characterize amino acid-related metabolic differences between heart failure with moderately reduced ejection fraction (HFmrEF) (LVEF 40–49%) and HFrEF (LVEF < 40%) and to derive a biologically interpretable composite metabolomic index capable of discriminating between these two stages of systolic dysfunction. We conducted a cross-sectional metabolomic analysis of 42 patients stratified by left ventricular ejection fraction (LVEF < 40% vs. 40–49%). The reference group comprised patients with mildly reduced ejection fraction (LVEF 40–49%), without inclusion of individuals with preserved or normal cardiac function. Targeted amino acid profiling was performed using liquid chromatography-tandem mass spectrometry (LC–MS/MS). Metabolites were standardized and analyzed individually and in combination. A composite index (Heart Failure Amino Acid-Derived Systolic Index: HASI-40), integrating markers of proteolysis and metabolic resilience, was derived to distinguish patients with HFrEF from those with HFmrEF. Discrimination was assessed using receiver operator curve (ROC) analysis with internal validation and multivariable adjustment. Patients with LVEF < 40% exhibited a coordinated metabolic phenotype characterized by reduced methionine, sarcosine, serine, and taurine. While individual metabolites did not retain significance after multiple-testing correction, the composite HASI-40 index remained strongly associated with HFrEF (OR 5.56, 95% CI: 1.70–18.14; p = 0.004), although the wide confidence interval indicates limited precision due to sample size. The index demonstrated good discrimination with an area under the curve (AUC) of 0.862, which improved when combined with age (AUC 0.932). The index represents a standardized composite measure and does not define a diagnostic cutoff for individual patients. These findings suggest that HFmrEF and HFrEF exhibit partially distinct metabolic phenotypes despite overlapping clinical characteristics. These findings suggest that HASI-40 captures metabolic differences between patients with HFmrEF (LVEF 40–49%) and those with HFrEF (LVEF < 40%), reflecting progression toward more advanced systolic dysfunction. However, due to the absence of a control group with preserved ejection fraction, small sample size, and lack of external validation, the index should be considered exploratory and hypothesis-generating rather than clinically applicable. Full article

The present study provides a comprehensive investigation into the hydrodynamic performance of grooved rubber journal bearings (GRJBs) employed as shaft supports in various rotating systems, with particular emphasis on marine applications. These bearings are lubricated with non-Newtonian fluids such as modern oil containing additives and viscoelastic water-based lubricant, which—owing to its complex composition including hydrocarbon chains, metal oxides, and impurity particles and contaminants such as salts, organic substances, microalgae, biopolymers, and microorganisms—deviates from the ideal Newtonian fluid model and demonstrates non-Newtonian rheological behavior. By examining various theories used in the analysis of non-Newtonian fluid behavior, the power-law model, which has a high degree of generality, has been employed in the present study. Also, to improve modeling accuracy, the elastic deformation of the rubber bush in this study is characterized using the Winkler foundation approach and analyzed via the finite element method (FEM). This advanced mechanical formulation, integrated with non-Newtonian lubrication modeling of lubricant using the power-law fluid model, and the parametric assessment of groove number and dimensions on steady-state bearing performance parameters, constitutes the core of this research. The investigation focuses on groove configurations of 4, 6, 8, and 10 channels. The findings indicate that increasing the groove count partitions the convergent pressure film zone into discrete segments, thereby reducing the maximum hydrodynamic pressure while intensifying the overall energy dissipation within the bearing. Additionally, the influences of rheological properties of the fluid—namely the power-law index (n) and the consistency index (m)—on key performance characteristics are thoroughly examined. An increase in both parameters enhances the effective viscosity and load carrying capacity; however, the exponential amplification due to the power-law index exhibits a more pronounced effect on load capacity and peak pressure compared to the consistency index. Full article

Concrete and cementitious composites exhibit brittle failure under shear stress, limiting their resilience in seismic and high-load applications; this study investigates whether crimped NiTi shape memory alloy (SMA) fibers can enhance pure shear strength and ductility of mortar specimens, with particular focus on the effect of thermal activation. Z-shaped mortar specimens were prepared with SMA fiber volume fractions of 0%, 1.0%, and 1.25%, tested under both non-heated and heated conditions using a Universal Testing Machine, with deformation monitored via LVDTs and Digital Image Correlation. SMA fiber reinforcement increased peak shear strength by 13% and 14.5% for 1.0% and 1.25% fiber volumes, respectively, under ambient conditions, reaching up to 22% enhancement after thermal activation due to recovery-stress-induced prestressing; the 1.0% fiber volume achieved the highest ductility index of 4.05 compared to 1.03 for plain mortar, while SMA fibers had negligible influence on initial shear modulus but substantially improved post-cracking response and crack bridging. These findings demonstrate that crimped SMA fibers effectively improve shear resilience of cementitious composites, with 1.0% fiber content offering the optimal balance between strength and ductility, though activation protocols require careful calibration to minimize thermal degradation of the matrix. Full article

Tantalum pentoxide (Ta₂O₅) has emerged as a versatile material at the intersection of optical coatings and integrated photonics because it combines a high refractive index, a wide bandgap, low optical loss, and compatibility with multiple thin-film deposition routes. Over the past decade, the literature has expanded from conventional dielectric coating studies to low-loss waveguides, micro-ring resonators, wavelength conversion, and broadband supercontinuum generation, while more recent work has increasingly emphasized defect engineering, nonlinear absorption, and laser damage reliability under strong optical fields. The objective of this review is to establish a process–structure–composition–property–function–reliability framework for understanding Ta₂O₅ and non-stoichiometric Ta₂O_5−x optical coatings in high-power photonics. Unlike previous reviews that mainly emphasized dielectric properties, deposition methods, or general thin-film applications, this review highlights how deposition-induced composition changes, oxygen vacancy-related defects, nonlinear optical response, and laser damage reliability jointly determine the operational limits of tantalum oxide photonic materials. Particular attention is given to ion-assisted and ion gun-assisted processes, which have repeatedly been associated with higher film density, smoother morphology, reduced oxygen vacancy-related loss, and more stable high-field behavior. By linking coating-level process control to device-level functions such as four-wave mixing, self-phase modulation, wavelength conversion, and supercontinuum generation, this review highlights how thin-film engineering governs both optical performance and operational limits. It also identifies several persistent gaps, including the need for standardized reporting of nonlinear absorption, unified damage metrics across film and device geometries, and stronger correlations among microstructure, composition, defects, and long-term optical stability. Overall, this review provides a composition-aware and coating-informed framework for interpreting Ta₂O₅ photonics and a practical roadmap for developing durable high-power photonic components. Full article

The pursuit of sustainable winter road maintenance has intensified the need for deicers that balance functional effectiveness, economic viability, and minimal environmental impact. However, the absence of a systematic, multi-dimensional evaluation framework has hindered informed product selection and green procurement. This study develops and validates the Comprehensive Deicer Multi-criteria Evaluation System (CDMES)—a structured assessment framework that integrates economic, functional, environmental, and infrastructural sustainability dimensions. The evaluation index system was constructed for deicers, consisting of 18 indicators including preparation cost, engineering maintenance cost, operability of agent preparation, application difficulty, asphalt binder adhesion loss, minimum application concentration, proportion of active ingredients, effective time, ambient temperature, freezing point, solid dissolution rate, relative snow/ice-melting capacity, seed damage rate, chlorophyll attenuation, soil pH, aqueous solution pH, steel–carbon corrosion rate, and pavement friction attenuation rate. Subsequently, the analytic hierarchy process (AHP) was employed to determine the weight of each indicator, and evaluation criteria were established in accordance with relevant standards and literature. Finally, this weight determination method, combined with the simple additive weighting (SAW) method for index aggregation, forms a quantitative evaluation model. These elements together constitute a comprehensive deicer evaluation system, designated as the Comprehensive Deicer Multi-criteria Evaluation System (CDMES). Validation using three representative deicers—sodium chloride, a composite chloride-based formulation, and an organic acetate-based product—demonstrated that the CDMES can effectively discriminate product performance across multiple sustainability dimensions and identify critical weaknesses that may be obscured by purely compensatory scoring. The framework offers a transparent and reproducible decision-support tool for winter maintenance managers seeking to align deicer selection with sustainability objectives. Full article

Microalgae-based biostimulants are gaining increasing interest worldwide for promoting sustainable agriculture. The environmental risks associated with synthetic agrochemicals can be mitigated by using microalgae to enhance crop yield and quality. Cumin (Cuminum cyminum L.) is an herbaceous plant and ranks among the most popular seed spices worldwide. It is characterized by a low germination rate and poor seedling establishment, which negatively impact overall crop yield. To address these challenges, the present study investigates the potential of Chlorococcum sp. aqueous extract as a sustainable and cost-effective solution to overcome cumin seed dormancy and enhance germination. Results showed that Chlorococcum sp. exhibits a notably rapid growth rate (0.45 day⁻¹) and high biomass productivity (1.51 g/L/day). Additionally, the biochemical composition of the extract revealed a high concentration of bioactive compounds, including polyphenols (63.46%), flavonoids (29.36%), and Indole-3-acetic acid (5.38%), which make it an eco-friendly biostimulant for agricultural applications. Regarding germination, a single seed treatment with doses of 0.5 g/L and 1 g/L was efficient in achieving final germination percentages of 100% and 96.66%, respectively, and significantly increased the seedling vigor index and photosynthetic pigment content. Furthermore, these concentrations stimulated the synthesis and accumulation of key primary metabolites, including proteins and polysaccharides, while increasing phenolic and flavonoid levels compared to the control, suggesting enhanced growth and improved antioxidant defenses against environmental stressors. Overall, these findings highlight that Chlorococcum sp. aqueous extract serves as an innovative biological approach to overcoming cumin seed dormancy and enhancing germination, offering an alternative and sustainable solution to conventional synthetic fertilizers. Full article

Background: Accurate three-dimensional positioning of dental implants is critical for ensuring biomechanical stability, prosthetic passivity, and long-term clinical success. While computer-assisted navigation systems achieve high precision, their complexity and cost often limit accessibility. This study presents the development and preclinical experimental validation of a low-cost prototype designed to enhance angular accuracy in dental implant placement within a controlled 3D haptic simulation environment. Methods: A preclinical experimental design was implemented using a 3D haptic simulator (Virteasy, Montpellier, France). The prototype incorporated high-precision inertial measurement units (IMUs) and an Extended Kalman Filter (EKF) for real-time angular feedback. Ninety-seven simulated implant placements were performed—both freehand and with prototype assistance—under identical virtual conditions by a single experienced operator. Angular deviations in mesiodistal and buccolingual planes were recorded, combined into a composite 3D index, and analyzed using paired t-tests and linear mixed-effects models. The study was conducted in a controlled simulation environment, which does not fully replicate clinical conditions. Results: The prototype significantly reduced angular deviation from 13.49° to 2.99° in the mesiodistal plane (−77.8%) and from 13.56° to 5.59° in the buccolingual plane (−58.8%), achieving an overall 67% improvement in three-dimensional orientation (p < 0.001; Cohen’s d = 1.47). Agreement with an optical reference system (OptiTrack) was excellent (bias = +0.36°, RMSE = 0.39°). Intra-operator reliability exceeded 0.95 (ICC), confirming strong reproducibility and measurement stability. Conclusions: The proposed inertial sensor-based prototype achieved angular accuracy within the range reported for computer-guided systems while maintaining advantages of portability, low cost, and usability. Its integration into haptic simulators provides a valid tool for both educational and preclinical applications, offering real-time feedback that enhances spatial perception and psychomotor learning. Future clinical studies should validate its performance in cadaveric and patient-based contexts to determine its practical impact on surgical precision and implant success. Full article

To reveal the long-term anti-aging mechanisms of rubber–plastic elastomer-modified asphalt in complex service environments and overcome the inherent defects of single polymer modifiers—namely their susceptibility to degradation or phase separation—this study prepared styrene-butadiene-styrene (SBS), low Mooney rubber (LMMR), and low-density polyethylene (LDPE)-modified asphalts. Simultaneously, an LMMR-LDPE rubber–plastic thermoplastic elastomer (TPE) was fabricated utilizing twin-screw extrusion technology and subsequently used to prepare a composite-modified asphalt. Three aging protocols were simulated: short-term thermo-oxidative aging (RTFOT), long-term pressure aging (PAV), and ultraviolet light aging (UV). A multi-scale quantitative characterization was conducted using a dynamic shear rheometer, Fourier transform infrared spectroscopy, and atomic force microscopy to evaluate the rutting factor, carbonyl index, and surface microroughness of each system before and after aging. The experimental results indicate that the coupled effect of long-term stress and thermal oxidation causes the most severe damage to the colloidal structure of modified asphalt. Conventional SBS-modified asphalt, due to its abundance of unsaturated double bonds, exhibits a sharp increase in the carbonyl index and aging index of the rutting factor after aging, making it highly susceptible to oxidative chain scission. Although LDPE-modified asphalt possesses chemical inertness, it is prone to crystalline phase separation under aging conditions, resulting in a microroughness distortion rate of up to 86.36%. In contrast, the LMMR-LDPE composite system, leveraging the high chemical stability of the saturated aliphatic carbon chain and the flexibility-enhancing and crystallization-inhibiting effects of LMMR, effectively reduces active oxidation sites and improves interfacial compatibility. This composite system exhibits the lowest carbonyl increment and rheological attenuation under all aging conditions, while effectively inhibiting the free migration and agglomeration of macromolecular components. The LMMR-LDPE composite modification technology effectively overcomes the inherent drawbacks of single polymers, such as susceptibility to degradation or segregation, demonstrating excellent long-term macroscopic rheological stability and microscopic phase morphology anti-aging capability. The present findings provide laboratory-scale mechanistic support for the design of durable rubber–plastic-modified asphalt systems, while further pilot-scale, economic, and field validation is still required before practical engineering application can be fully assessed. Full article

Wound-associated infections persist as a major global health concern, particularly in the context of increasing antimicrobial resistance and reduced efficacy of conventional therapies. Essential oils (EOs) obtained from medicinal plants represent promising alternatives due to their antimicrobial and wound-healing properties. This study evaluated the chemical composition, antimicrobial activity, and interaction effects of Hypericum perforatum (HP) and Achillea millefolium (AM) EOs, tested individually and in fixed-ratio combinations. Chemical profiling by GC–MS revealed that HP EO is dominated by caryophyllene (20.74%) and β-thujone (18.47%), while AM EO is characterized by aromadendrene (19.12%), caryophyllene (12.97%), and chamazulene (10.13%). Antimicrobial activity was assessed against wound-associated microorganisms using MIC and MBC/MFC assays, and interactions were assessed by the fractional inhibitory concentration index (FICI) and heatmap analysis. The results displayed higher susceptibility of Gram-positive bacteria, particularly Staphylococcus epidermidis, with MIC values as low as 0.56 µL/mL in EO combinations. Synergistic effects were observed exclusively for S. epidermidis in mixtures enriched in HP EO (60:40 and 70:30; FICI = 0.34), while Gram-negative bacteria and Candida albicans exhibited predominantly indifferent responses. These findings indicate that optimized EO combinations may enhance antimicrobial efficacy and support their potential application in wound management. Full article

Digital transformation calls for new models of sustainable regional development, particularly in spatially heterogeneous emerging economies where interregional cooperation and network effects play an important role in reducing disparities and supporting the gradual formation of integrated development systems. This study aims to develop a conceptual governance model based on innovative hyperclusters defined as transregional multi-sector network structures integrating digital platforms with circular economy principles. To achieve this goal, a composite ESG index was constructed by aggregating 26 statistical indicators (Environmental, Social, Governance) using a generalized Minkowski mean, and applied to empirically assessment of 85 Russian regions sustainable development. Regions were classified into five sustainability groups, from vulnerable to integrated. Most Russian regions fall into intermediate categories, while some lack the critical mass required for traditional cluster formation. The proposed hypercluster model functions as a digital bridge, allowing lagging regions to integrate into distributed value chains, access advanced competencies, and co-develop green technologies. This study offers a threefold contribution to the literature: first, a robust composite ESG indicator adapted to the Russian statistical framework; second, a novel governance model of innovative hyperclusters as a systemic tool for overcoming structural imbalances; third, empirically grounded differentiated application scenarios for Russian regions. Full article

The assessment of art learning outcomes has long relied on teachers’ subjective judgment, facing challenges such as inconsistent evaluation criteria and difficulty in multi-dimensional quantitative analysis. To address these issues, this study proposes a framework for the automatic assessment of art learning outcomes based on symmetry analysis of multi-dimensional aesthetic features. The model quantifies the symmetry between student works and instructional exemplars across three aesthetic dimensions: color distribution features (HSV color space histograms and dominant color composition), compositional features (visual center distribution and structural symmetry), and art movement style features (multi-layer Gram matrices from VGG-19 with PCA dimensionality reduction). Using publicly available artwork datasets, this study constructed Temporal Evolution Pairs (early and late works by the same artist) and Stylistic Inheritance Pairs (works by different artists within the same movement) to validate the model’s effectiveness. The experimental results demonstrate that the proposed multi-dimensional feature fusion strategy achieves 87.6% accuracy in artist style evolution trajectory recognition and 82.3% accuracy in art movement style inheritance quantification, significantly outperforming baseline methods including SSIM (52.3%), VGG-fc features (68.9%), and single style loss (76.4%). Two in-depth case studies further validate the model’s quantitative capability: in analyzing Picasso’s stylistic evolution, the Mastery Index and the Creativity Divergence Index successfully captured the stylistic continuity of adjacent periods (Blue Period to Rose Period: the Mastery Index = 73.6) and the breakthrough innovation of cross-period transformations (Rose Period to Cubism: the Creativity Divergence Index = 82.7). t-SNE visualization of the feature space further revealed that deep style features can clearly distinguish different art movements and individual artists, with spatial distances between artists closely corresponding to stylistic affinities. This research provides new perspectives and tools for a computational framework with the potential for art education assessment practice. It is important to emphasize that the reported performance demonstrates the model’s ability to quantify stylistic relationships between artworks but does not yet demonstrate its validity for assessing student learning outcomes in real classroom settings. As noted, the current validation is based on art-historical consensus, and direct application to educational contexts will require further validation with actual student works and expert evaluation, which we plan to address in future work. Full article

Epoxy resins have been extensively applied in aerospace and automotive fields. Nevertheless, their inherent flammability significantly restricts broader applications. In this study, carboxylated multi-walled carbon nanotubes (COOH-MWCNTs) were first aminated to obtain aminated Multi-Walled Carbon Nanotubes (NH₂-MWCNTs). Subsequently, NH₂-MWCNTs and ammonium polyphosphate (APP) were incorporated into the epoxy resin via mechanical stirring, thereby constructing a phosphorus–carbon synergistic flame-retardant system. Compared with the neat epoxy thermoset, the EP/17.5APP/0.1NH₂-MWCNTs composite showed a limiting oxygen index (LOI) value of 29.6% and attained a UL-94 V-0 rating. In addition, for the modified composite material, the maximum thermal decomposition rate (R_Tmax) is 12.4 wt%/min, the char residue at 600 °C (C₆₀₀) reaches 44.2%, and the smoke density is 425.8. The impact strength and tensile modulus are increased to 10.1 Mpa and 3.0 Gpa, respectively, while the compressive strength remains essentially unchanged. Furthermore, the synergistic flame-retardant mechanism between phosphorus and carbon was investigated by analyzing the char residues of the epoxy resin and its composites. This study offers a promising approach for designing epoxy composites with improved flame retardancy and enhanced thermal stability for high fire-safety applications, such as electronic encapsulation and structural materials. Full article

Photonic and acoustic jets are subwavelength wave localization phenomena formed in the near field of dielectric or elastic scatterers, enabling spatial resolution beyond classical diffraction limits and motivating applications in sensing, imaging, and wave–matter interaction control. This review places photonic and acoustic jets in a unified wave-physics framework and focuses on how composite and layered elements can be used to tune their properties. In photonic systems, refractive index contrast, layer thickness, and optical losses play key roles, while in acoustic systems, acoustic impedance mismatch, dispersion, and viscoelastic damping are critical. Models and numerical approaches, and experimental realizations in both optical and acoustic regimes, are reviewed and summarized to describe jet formation and to analyze the influence of material parameters and geometry. The main findings show that layered and composite scatterers, such as core–shell particles, multilayer spheres and cylinders, and graded-parameter metamaterials, provide additional degrees of freedom for controlling jet intensity, length, focal position, and directionality compared to homogeneous elements. Composite jet-forming elements offer a versatile platform for advanced wave localization and hold promise for metastructures, high-resolution sensing, integration into photonic and acoustic devices, and lab-on-chip technologies. Full article

As a sustainable alternative to petroleum-based plastics, psyllium gum, a natural hydrocolloid from Plantago ovata seeds, is reviewed for its application in packaging. This review focuses on the material properties of psyllium gum, including its film-forming capacity, water-binding capacity of 12–15 g/g, and rheological behavior (consistency index K = 10–50 Pa·sⁿ, flow behavior index n = 0.3–0.6), which are critical for packaging applications. We discuss how its performance can be enhanced through interactions with plasticizers, cross-linking agents, and blending with other biopolymers (e.g., polyvinyl alcohol and starch), as well as through nanocomposite reinforcement, to improve mechanical strength (tensile strength 5–15 MPa in native films; up to 48 MPa in thermoplastic starch composites), and barrier properties (e.g., oxygen permeability < 0.001 g/m² s). The review also provides a comparative analysis of psyllium-based films with other polysaccharide films and discusses the environmental benefits, such as a lower carbon footprint (GWP ≈ 1.2 kg CO₂-eq/kg) compared to PET (≈3.0 kg CO₂-eq/kg). Key challenges, including moisture sensitivity (equilibrium moisture content ~25% at 75% RH), raw material molecular-weight variability (±20%), and scalability, are outlined, along with future research directions, such as enzymatic extraction and the development of water-resistant, compostable formulations aimed at advancing psyllium gum toward viable next-generation sustainable food packaging materials. Full article