Search Results (33,123)

In many environmental applications, high-quality measurements are too sparse to resolve the small-scale patterns required for process understanding and management. We investigate a Bayesian kriging (BK) framework that densifies sparse coastal observations into high-resolution gridded fields with calibrated uncertainty. Two pilot sites are considered: (i) sea surface temperature (SST) in the Algarve (Portugal), where point measurements (~10 km spacing) are reconstructed on a 500 m grid, and (ii) chlorophyll (Chl) in the La Spezia embayment (Italy), where in situ supported fields are reconstructed at 30 m. The variogram parameters are treated as random variables with weakly informative priors and inferred via MCMC, so that both measurement noise and structural (variogram) uncertainty are propagated to predictions, yielding posterior means and 95% prediction intervals per grid cell. Independent repeated 80/20 cross validation demonstrates robust out-of-sample skill in both sites. For Algarve, the BK maps recover fine-scale thermal structure while preserving defensible uncertainty under severe sparsity. For La Spezia, the same framework resolves estuarine gradients at 30 m. Credible intervals widen away from observations yet remain sufficiently narrow elsewhere to guide interpretation. Satellite products are used strictly for validation on a common grid (MUR SST at 1 km resampled to 500 m, Landsat OC3 Chl at 30 m), confirming spatial fidelity and clarifying seasonal differences. Overall, the approach produces uncertainty-aware, high-resolution coastal fields from heterogeneous, sparse records, supporting reproducible EO analyses and risk-aware coastal monitoring. Full article

Low-Temperature Co-Fired Ceramic (LTCC)-based mechanical sensors are inherently limited by the thickness and rigidity of multilayer ceramic stacks, which restrict miniaturization and mechanical compliance. To overcome these constraints, this work presents a hybrid LTCC/Kapton^® platform enabling high-sensitivity mechanical sensing through mechanically tunable RF passive components. The proposed approach integrates a flexible polyimide membrane, bonded onto an LTCC substrate at low temperatures using selectively electroplated indium pillars that simultaneously define the air gap and provide mechanical fixation. Inductance tuning is achieved via metal-shielding proximity effects, whereas capacitance tuning relies on force-controlled air-gap modulation in a metal–insulator–metal configuration. The fabrication process ensures precise gap control, high compliance, and structural robustness without requiring deformable ceramic membranes. Experimental characterization, including three-dimensional surface profiling and impedance measurements, demonstrates a 48% inductance tuning range with a sensitivity of 0.715 nH/mN and a 36% capacitance tuning range with a sensitivity of 47.3 fF/mN at 1 MHz. The proposed hybrid platform provides a compact and scalable solution for high-sensitivity sensors and mechanically reconfigurable RF components suitable for harsh-environment and adaptive electronics applications. Full article

The Mar Menor is the second largest coastal lagoon in the Mediterranean Sea, with a surface area of about 136 km². It is restricted from the open sea by a sandy barrier system (La Manga) interrupted by three tidal inlets. As a result of high evaporation, it is hypersaline (42–47 ppt) in parts. This study examines the factors leading to the rise in sea surface temperature in the Mar Menor through an analysis of long-term sea surface temperature using HadSST1.1 data together with shorter-term Moderate-Resolution Imaging Radiometer and Optimum Interpolation Sea Surface Temperature data. A thermal box model has been constructed for the lagoon in an attempt to balance major heat sources and sinks. Additionally, a thermal probe was deployed in 0.3 m of water to evaluate the benthic flux of heat of the shelly fine sand that covers the lagoon seabed. The results show that the vertical thermal gradient in the seabed inverts between the day and night. Prior to circa 1977, there was no clear trend in SST, and variations were strongly associated with the Atlantic Mutidecadal Oscillation and the North Atlantic Oscillation. Post circa 1980, the maximum summertime sea surface temperature showed a steady increase of 0.34 °C/decade. The cross-correlation of SST in the Mar Menor with external drivers showed that it is dominated by the sea surface temperature of the Western Mediterranean, followed by local air temperature, with a minor contribution from the Indian Ocean Dipole. No other significant correlations were evident, suggesting that local temperature was dominated by local drivers. In addition, a Spearman rank order evaluation and principal component analysis showed that the general trends of the Mar Menor SST were also influenced by the Atlantic Multidecadal Oscillation, CO₂, and GDP. Full article

This study investigates the potential of pure chitosan powder as an effective, sustainable, and low-cost adsorbent for the removal of synthetic dyes from aqueous media. The work demonstrates the potential of pristine chitosan for practical wastewater treatment applications by adsorbing two commonly used textile dyes, methyl orange (MO) and methylene blue (MB). To elucidate the adsorption mechanism, chitosan was comprehensively characterized using zeta potential analysis, Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy (SEM–EDX), Thermogravimetric Analysis (TGA), Brunauer–Emmett–Teller (BET) surface area analysis, and point of zero charge (pHpzc) determination. FTIR analysis revealed notable shifts in –NH₂ and –OH functional groups after dye adsorption, confirming their involvement in electrostatic interactions and hydrogen bonding with MO and MB. SEM images demonstrated significant surface morphological changes following adsorption, while EDX spectra confirmed successful dye uptake through the appearance of sulfur and nitrogen signals characteristic of MO and MB, respectively. Zeta potential and pHpzc results explained the strong pH-dependent adsorption behavior, highlighting favorable electrostatic attraction between chitosan and the ionic dyes. The optimum adsorption conditions were achieved at adsorbent dosages of 0.5 g for MO and 1.0 g for MB, a contact time of 30 min, initial dye concentrations of 20 and 100 mg/L, and solution pH values of 3 for MO and 9 for MB at room temperature. The adsorption data fit the Langmuir isotherm model, indicating monolayer adsorption on a homogeneous chitosan surface, with maximum adsorption capacities of 7.843 mg/g for MO and 7.605 mg/g for MB. Kinetic studies showed that adsorption followed the pseudo-second-order model, suggesting chemisorption as the dominant mechanism. Thermodynamic analysis indicated that the adsorption process was endothermic and non-spontaneous under the investigated conditions. In conclusion, these findings demonstrate that unmodified chitosan is a practical, eco-friendly adsorbent for dye removal, achieving removal efficiencies comparable to many modified chitosan composites, and represents a promising candidate for sustainable wastewater treatment. Full article

Plastic recycling, also known as chemical recycling, is widely promoted worldwide as a sustainable way to reduce polymer waste and produce alternative fuel sources. One of the promising areas in this field is the thermocatalytic decomposition of plastics into hydrocarbon fractions suitable for use as motor fuel. This study investigates the feasibility of using natural Taizhuzgen zeolite separately modified with molybdenum and tungsten and activated by an acid-free method for the thermocatalytic hydrogenation of polymer waste. The catalyst was prepared by modifying the activated zeolite with molybdenum ((NH₄)₆Mo₇O₂₄·4H₂O) and tungsten ((NH₄)₅H₅[H₂(WO₄)₆]·H₂O) salts. Thermal catalytic hydrogenation experiments were conducted under controlled temperature and barometric conditions, and the resulting liquid products were separated into fractions with boiling points of 180 °C, 180–250 °C, and 250–320 °C. The individual and group hydrocarbon compositions of the gasoline, diesel, and heavy gas oil fractions were determined using gas chromatography–mass spectrometry. The structural and surface characteristics of the synthesized composite catalysts were studied using electron microscopy and physicochemical analysis. The results show that Taizhuzgen zeolite modified with molybdenum and tungsten exhibits favorable textural properties and catalytic activity, which increases the yield of liquid fuel fractions. The developed catalyst is promising for use in the resource-efficient thermal catalytic processing of polymer waste into motor fuel. Full article

To address the dual challenges of aqueous phosphate pollution and the resource utilization of petrochemical solid wastes, this study proposes a novel closed-loop “waste-to-waste” strategy. This approach innovatively integrates multiple solid wastes (including oily sludge and petroleum hydrocarbon-contaminated soil) into a porous ceramic matrix and utilizes lanthanum recovered from spent catalysts for surface modification, successfully fabricating an optimized adsorbent—lanthanum-modified ceramsite (BC@La). Under the conditions of pH 6, an adsorbent dosage of 1 g/L, and a temperature of 318 K, BC@La achieved a maximum phosphate adsorption capacity of 2.56 mg/g, corresponding to 128.0 mg of phosphorus per gram of La. Kinetic and isotherm analyses revealed that the adsorption process followed the pseudo-second-order model and fitted well with the Langmuir isotherm, consistent with monolayer chemisorption. Thermodynamic studies further indicated that the adsorption was spontaneous and endothermic. The primary adsorption mechanism was attributed to the precipitation of lanthanum phosphate (LaPO₄). This study not only demonstrates a high-performance adsorbent but also provides a sustainable strategy for the synergistic utilization of industrial solid wastes. Full article

To elucidate how tempering temperature influences through-thickness microstructure and strength–toughness gradients in an online direct-quenched (DQ) low-alloy medium-thick plate, a 25-mm plate was direct-quenched from 900 °C to <150 °C and tempered at 530 °C × 1.5 h or 580 °C × 1.5 h. Tensile and room-temperature Charpy V-notch impact testing and microstructure characterization were performed at the upper surface, mid-thickness, and lower surface. In the as-DQ state, the upper surface contained ferrite (F, ~60%) and granular bainite (GB, ~30%) with minor lath bainite (LB, ~10%) and a small amount of martensite/austenite (M/A). The mid-thickness and lower surface remained dominated by F + GB (mid-thickness: GB~50%, F~30%, M/A~20%; lower surface: F~85%, GB~15%); the mid-thickness showed the lowest yield strength/ultimate tensile strength (YS/UTS) of 498/675 MPa. In the as-DQ state, the room-temperature Charpy V-notch absorbed energies at the upper surface, mid-thickness, and lower surface were 223.23, 229.88, and 261.22 J, respectively, indicating a pronounced through-thickness variation (ΔE_(max–min) ≈ 38 J). After tempering at 530 °C, the upper surface and mid-thickness developed an F + tempered sorbite (TS) microstructure (upper surface: F~70%, TS~30%; mid-thickness: F~60%, TS~40%), whereas the lower surface was mainly ferrite with a small amount of spheroidized carbides/tempered cementite (SC). The mid-thickness YS/UTS increased to 619/805 MPa, and the impact energies at the upper surface and mid-thickness increased to 240.62 J and 235.56 J, respectively, resulting in a reduced through-thickness gradient. After 580 °C tempering, recovery and polygonal ferrite formation dominated; surface yield strength increased but mid-thickness yield improvement was limited. Full article

As global warming intensifies, urban heat stress is increasing. Urban blue–green spaces (UBGSs) reduce heat exposure, and refined planning can enhance cooling in space-limited cities. Yet drivers and mechanisms at the urban-agglomeration scale remain unclear. This study quantified the cooling intensity (CI) of 162 UBGS across 27 cities in the Yangtze River Delta using summer 2020 land surface temperature data (June–August). CI is defined as the average temperature difference (ΔLST) between the UBGS and its surrounding buffer. Extreme gradient boosting (XGBoost) and Shapley additive explanations (SHAP) methods were applied to analyze the driving factors. Key findings include (1) the top five factors by SHAP value: Area (0.38), buffer NDBI (0.16), lake/river landscape shape index (0.07), buffer tree height (0.06), and buffer population (0.06). (2) CI rises with Area only up to 50 hm² and then plateaus at ~6 °C. Buffer NDBI strengthens CI, with faster gains when buffer NDBI < −0.2. Water-shape effects are stepwise, and a lake/river shape index of 5–8 delivers near-optimal cooling. Interactions indicate stronger cooling in large parks with high water coverage and in sites combining complex water edges with dominant grassland patches. These findings support structure-focused UBGS design and targeted mitigation in dense urban areas. Full article

This study investigates the quasi-static and fatigue strength of copper-brazed 316L stainless steel. Quasi-static and fatigue tests were conducted at room temperature (20 °C) using a Zwick/Roell Vibrophore 100 testing machine and specially designed copper-brazed specimens. Two types of specimens were prepared—tensile and shear specimens—to obtain the stress–strain relationships (σ–ε and τ–ε) and the fatigue life (S–N) curves. Based on the experimental results, the quasi-static and fatigue strengths of the copper-brazed joints under external tensile and shear loading were evaluated. The fatigue tests reveal that the shear fatigue strength is significantly lower than the tensile fatigue strength. Furthermore, a comprehensive investigation was conducted, focusing on the metallographic characterisation of the brazed joint and fractographic analyses of fracture surfaces obtained under quasi-static and fatigue loading, with particular emphasis on the shear strength of the investigated brazed joint. The experimental results obtained may be crucial for designing engineering structures (e.g., plate heat exchangers), where copper-brazed joints are the weakest members of the structure. Full article

The rising demand for wireless electronics and sustainable energy solutions drives the search for alternatives to conventional batteries. Triboelectric nanogenerators (TENGs) offer a promising route by converting mechanical energy into electricity via frictional events between two different material surfaces. Here, a simple and scalable surface modification method using conventional laser printing was applied to investigate the effect on triboelectric performance of cellulose-based materials against polytetrafluoroethylene (PTFE). Regenerated cellulose (RC) and cellulose acetate (CA) films were print patterned with black toner in a conventional laser printer at different surface coverages from 0% to 100%. The measured power output for RC films against PTFE showed minimal response from the patterning over the whole range and could be considered as constant with an average of 52 ± 2 W m⁻². On the other hand, the CA sample films showed a significant and gradual increase in power output from 45 to 65 W m⁻² as the toner print coverage increased from 0% to 100%. These results demonstrate that synergistic interactions between the printed toner and the substrate can strongly influence TENG performance and are highly dependent on the physical and chemical properties of the underlying material. In CA, toner–substrate intermixing enabled by laser printing temperatures exceeding the glass transition temperature provides a proof-of-concept for enhancing triboelectric performance through controlled surface–bulk interactions. Full article

Heavy metal contamination, particularly lead, poses significant environmental and health risks. In this study, a multifunctional TiO₂@PLDOPA@Fe₃O₄ (TPF) nanocomposite was synthesized and evaluated as a reusable adsorbent for lead ion (Pb(II)) removal from aqueous solutions. Batch adsorption experiments were conducted to examine the effects of contact time, temperature, solution pH, adsorbent dosage, and shaking speed on adsorption performance. A high Pb(II) removal efficiency of 84% and an equilibrium adsorption capacity of 72.38 mg g⁻¹ were obtained under optimized conditions. Kinetic analysis revealed that Pb(II) adsorption followed a pseudo-second-order model, indicating surface-controlled interactions. Thermodynamic analysis suggested a spontaneous and endothermic adsorption process dominated by physical interactions and electrostatic attraction Equilibrium data were better fitted by the Freundlich model, suggesting heterogeneous multilayer adsorption on the functionalized composite surface. The maximum monolayer adsorption capacity of TPF reached 263.16 mg g⁻¹, exceeding those of pristine TiO₂ and Fe₃O₄. Regeneration studies showed that the TPF nanocomposite retained approximately 87% of its initial adsorption capacity after five adsorption-desorption cycles, demonstrating good stability and reusability. The integration of hierarchical TiO₂, magnetic Fe₃O₄, and bio-inspired PLDOPA functionalization provides a promising and sustainable strategy for heavy metal removal and highlights the potential of multifunctional nanocomposites in circular and resource-efficient water treatment systems. Full article

This study presents a sustainable strategy for improving the thermal properties of pine wood through the application of calcium carbonate nanopowder (CCNP) chelated with polycarboxylic acids (citric acid (CA) and tartaric acid (TA)) as coatings. The chelation reaction was confirmed by the detection of carbon dioxide (CO₂) gas. CCNP was characterized using microscopy and particle size analysis. The formation of crystalline calcium citrate and calcium tartrate was verified using FTIR and Raman spectroscopies, and XRD analysis. Wood treatment was conducted using different volumetric ratios of CA and TA. The CA-TA-treated (coated) wood blocks achieved the highest mass gain after treatment of around 89%, while the pure TA treatment exhibited enhanced leaching resistance, maintaining around 69% mass gain after leaching test. TGA conducted under oxidative (air) conditions showed that the coatings promoted char formation and produced inorganic residues from 6.4% to 7.8%, with the control resulting in negligible residual mass. Flame retardancy tests showed that the chelated coatings effectively delayed combustion and inhibited heat transfer, with the TA treatment showing improved flame retardancy performance by limiting the surface temperature to ~200 °C after 60 s of exposure, as compared to >550 °C for the control. Full article

This study assessed the conservation priorities for Cycas panzhihuaensis, a relict plant endemic to the dry-hot valleys of the Jinsha River, by integrating habitat suitability prediction with habitat quality evaluation. We used the MaxEnt model to identify its potential distribution and key environmental drivers and the InVEST model to evaluate habitat quality and degradation risk within the study area. Conservation priorities—categorized as hotspots, transition zones, and coldspots—were delineated by overlaying suitability classes with habitat quality levels. Spatial clustering of hotspots was examined using global spatial autocorrelation analysis. The results indicate that: (1) The highly suitable habitat for C. panzhihuaensis covers an area of 799.12 km², primarily concentrated in the dry-hot valleys of the Jinsha, Yalong, and Anning Rivers. January land surface temperature was the most significant environmental determinant of its distribution (contribution: 36.1%). (2) The overall habitat quality of the study region was relatively low (mean: 0.38), with a moderate risk of degradation. Areas of severe degradation spanned 14,629.31 km² (26.10% of the total area), largely coinciding with the river valleys and showing substantial overlap with the species’ suitable habitat. (3) The identified conservation hotspots (799.63 km²) exhibited a moderate and statistically significant positive spatial autocorrelation (global Moran’s I = 0.326). This integrated approach provides a spatially explicit framework for conservation planning, offering valuable insights applicable to other rare species in human-impacted landscapes. Full article

This study employs a mono-caprylate waterborne polyurethane microencapsulation technique to construct a core–shell phase-change microcapsule system with a structured composite core material. By integrating a silica network with phase change materials (ethyl palmitate/paraffin), a stable core material is formed. The silica not only acts as a physical framework to prevent leakage but also regulates the phase change temperature and latent heat through molecular interactions at its surface active sites. The shell layer polyurethane, derived from a fatty acid monoglyceride prepolymer, exhibits a structure highly similar to that of the core material, ensuring efficient and complete encapsulation, while the aqueous system aligns with green manufacturing requirements. The system successfully achieves two types of performance-tunable microcapsules: the silica–ethyl palmitate type exhibits a broad phase change temperature range near room temperature, while the silica–paraffin type demonstrates high latent heat of phase change in the medium-temperature range. This diversity in performance broadens the material’s application scenarios. Its broad temperature range characteristic is particularly suitable for building energy efficiency and electronic thermal management fields, effectively mitigating temperature fluctuations and reducing energy consumption, demonstrating significant application value and innovative potential. Full article

Partial oxidation of methane (POM) is a good way to make syngas because it uses exothermic reactions to keep itself going. This study made a series of Ni/KIT-6 catalyst precursors with Gd (0.5–2 wt.%) added to them and then carefully looked at how they changed into active catalysts. The first tests on the precursors using N₂ physisorption, XRD, and H₂-TPR showed that they had a high surface area and changed how they reduced. However, the high-temperature activation (700 °C) and reaction (682 °C) conditions caused thermal evolution and sintering. Tests of catalytic performance and RSM optimization found that the 5Ni + 1Gd/KIT-6 formulation was the best. Under the best conditions, it converted 89.0% of CH₄ and 87.4% of H₂. Using TEM and Raman spectroscopy to look at the used catalysts showed that 1 wt.% Gd was able to control the size distribution of the metallic particles and stop disordered carbon from forming, even after thermal recrystallisation. A 24 h stability test confirmed these findings, indicating a stable H₂ yield (85–87%) and minimal performance degradation, thereby demonstrating that Gd promotion maintains the stability of the active metallic phase under operational stress. Full article