Search Results (1,161)

The urgent need for advanced analytical tools for environmental monitoring and food safety drives the development of novel biosensing approaches and solutions. A computationally driven workflow for the development of a rapid electrochemical aptasensor for okadaic acid (OA), a critical marine biotoxin, is reported. The core of this strategy is a rational design process, where in silico modeling was employed to optimize the biological recognition element. A 63-nucleotide aptamer was successfully truncated to a highly efficient 31-nucleotide variant. Molecular docking simulations confirmed the high binding affinity of the minimized aptamer and guided the design of the surface immobilization chemistry to ensure robust performance. The fabricated sensor, which utilizes a ferrocene-labeled aptamer, delivered a sensitive response with a detection limit of 2.5 nM (n = 5) over a linear range of 5–200 nM. A significant advantage for practical applications is the remarkably short assay time of 5 min. The sensor’s applicability was successfully validated in complex food matrices, achieving excellent recovery rates of 82–103% in spiked mussel samples. This study establishes an integrated computational–experimental methodology that streamlines the development of high-performance biosensors for critical food safety and environmental monitoring challenges. Full article

Based on the steel sheet pile cofferdam project for the main bridge piers of a cross-sea bridge, finite element numerical simulations were conducted to analyze the influence of construction sequences in marine environments, as well as the effects of initial water levels and support positions under various construction conditions on the stress and deformation behavior of steel sheet piles. Using a staged construction simulation with a Mohr–Coulomb soil model and stepwise activation of loads/excavation, this study delivers practically relevant trends: staged dewatering halves the sheet pile head displacement (top lateral movement <0.08 m vs. ~0.16 m in the original scheme) and mobilizes the support system earlier, while slightly increasing peak bending demand (~1800 kN·m) at the bracing elevation; the interaction between water head and brace elevation is explored through fitted response curves and summarized in figures/tables, and soil/structural properties are tabulated for reproducibility. The results indicate that a well-designed dewatering process, along with the coordination between water levels and internal support positions, plays a critical role in controlling deformation. The findings offer valuable references for the design and construction of sheet pile cofferdams in marine engineering under varying construction methods and water level conditions. Full article

The recurrent influx of invasive Sargassum horneri along the coasts of South Korea poses significant ecological and economic challenges, including habitat disruption, aquaculture damage, and shoreline pollution. This study investigates a sustainable valorization pathway by converting SH into functional biochar through slow pyrolysis and utilizing the product as a core material for eco-friendly marine buoys. Biochars were produced at pyrolysis temperatures ranging from 300 °C to 700 °C and characterized for elemental composition, FT-IR spectra, leachability (CODcr), and biodegradability. Higher pyrolysis temperatures resulted in lower H/C and O/C molar ratios, indicating enhanced aromaticity and hydrophobicity. The biochar produced at 700 °C (SFBW-700) exhibited the highest structural and environmental stability, with minimal leachability and resistance to microbial degradation. A composite buoy was fabricated by mixing SFBW-700 with natural binders (beeswax and rosin), forming solid specimens without synthetic polymers or foaming agents. The optimized composition (biochar:beeswax:rosin = 85:10:5) showed excellent performance in density, buoyancy, and impact resistance, while fully meeting the Korean eco-friendly buoy certification criteria. This work presents a circular and scalable approach to mitigating marine macroalgal blooms and replacing plastic-based marine infrastructure with biochar-based eco-friendly composite alternatives. The findings suggest strong potential for the deployment of SH-derived biochar in marine engineering applications. Full article

This review focuses on five native Australian brown algae species—Cystophora torulosa, Durvillaea potatorum, Ecklonia radiata, Hormosira banksii, and Phyllospora comosa—evaluating their environmental adaptability, biochemical composition, bioactive compounds, and potential for commercial development. Species-specific differences in temperature and light tolerance influence their habitat distribution. Nutritional assessments reveal that these algae are rich in proteins, polysaccharides, polyunsaturated fatty acids, and essential trace elements. Bioactive compounds, including polyphenols and fucoidans, exhibit antioxidant, anti-inflammatory, and anti-diabetic properties. D. potatorum extracts have considerable economic value in agriculture by enhancing crop yield, improving nutritional value, and promoting root development. C. torulosa is predominantly found in cooler marine environments and is comparatively more thermally sensitive. In contrast, H. banksii has a higher heat tolerance of up to 40 °C and thrives in warmer environments. E. radiata is widely distributed, highly tolerant of environmental stresses, and exhibits notable disease-resistant activities. P. comosa, due to its high polysaccharide content, demonstrates strong potential for industrial applications. Consumer studies indicate growing acceptance of seaweed-based products in Australia, although knowledge gaps remain. This study highlights the need for continued research, optimized processing methods, and targeted education to support the sustainable development and utilization of Australia’s native brown algae resources. Full article

The Permian Kupferschiefer shale, a key stratigraphic unit within the Zechstein sequence of the Fore-Sudetic Monocline, represents both a metal-rich lithofacies and a potential source rock for hydrocarbon generation. This study presents a comprehensive geochemical characterization of selected Kupferschiefer samples obtained from the Legnica–Głogów Copper District (LGOM) and exploratory boreholes. Analytical methods included Rock-Eval pyrolysis, Py-GC/FID, elemental analysis, TG-FTIR, biomarker profiling, and stable carbon isotope measurements. Results indicate that the shales contain significant amounts of Type II and mixed Type II/III kerogen, derived primarily from marine organic matter with minor terrestrial input. The organic matter maturity, expressed by T_max, places most samples within the oil window. Rock-Eval S2 values exceed 60 mg HC/g rock in some samples, confirming excellent generative potential. Py-GC/FID data further support high hydrocarbon yields, particularly in samples from the CG-4 borehole and LGOM mines. The thermal decomposition of kerogen reveals multiple degradation phases, with evolved gas analysis identifying sulfur-containing compounds and hydrocarbons indicative of sapropelic origin. Isotopic compositions of bitumen and kerogen suggest syngenetic relationships and marine depositional settings, with samples from a North Poland borehole showing isotopic enrichment consistent with post-depositional oxidation. Kinetic parameters calculated using the Kissinger–Akahira–Sunose method demonstrate variable activation energies (107–341 kJ/mol), correlating with differences in organic matter composition and mineral matrix. The observed variability in geochemical properties highlights both regional and facies-dependent influences on the shale’s generative capacity. The study concludes that the Kupferschiefer in southwestern and northern Poland exhibits substantial hydrocarbon generation potential. This potential has been previously underestimated due to the unit’s thinness, but localized zones with high TOC, favorable kerogen type, and low activation energy could be viable exploration targets for natural gas. Full article

Propellers are essential aerodynamic components widely used in aerospace engineering, marine vessels, and aerial platforms. With the growing demand for high-thrust electric unmanned aerial vehicles, greater emphasis is being placed on improving propeller aerodynamic performance and efficiency to enhance flight endurance and payload capacity. Traditional design methods, mostly based on blade element theory, simplify the blade into two-dimensional planar elements, making it difficult to accurately capture the three-dimensional streamline characteristics during rotation. This mismatch between geometric design and actual flow limits further improvements in propulsion efficiency. This paper proposes a two-dimensional airfoil body-fitted design method to address this limitation. This method is based on blade element theory and vortex theory to obtain the chord length and pitch angle distribution under specific operating conditions. Based on these distributions, each blade element is bent to fit a virtual cylindrical surface at the corresponding position. This ensures that all points on the two-dimensional airfoil are equidistant from the hub center. The proposed design method is validated through numerical simulations. The results show that the propeller designed with the body-fitted method improves efficiency by 4.2% compared with the one designed using blade element theory. This work provides a new technical approach for propeller design and has practical value for improving propeller efficiency. Full article

This study investigates the dynamics and sources of atmospheric mercury in Qinhuangdao (QHD), a coastal urban area significantly impacted by both marine and terrestrial sources. Sampling of gaseous elemental mercury (GEM), fine particle-bound mercury (PBM_2.5), and coarse particle-bound mercury (PBM_2.5–10) was conducted from September 2022 to August 2023. The annual mean concentrations of GEM, PBM_2.5, and PBM_2.5–10 were 2.66, 1.01, and 0.73 ng m⁻³, respectively, with PBM levels among the highest reported for coastal cities in eastern China. GEM displayed a pronounced midday peak (12:00–14:00) with correlations to temperature (R² = 0.25–0.65) and a significant winter association with SO₂ (R² = 0.52), suggesting the combined influence of surface re-emission and coal combustion. Seasonal variations in the GEM/CO ratio (spring: 7.12; winter: 2.62) further reflected the shift between natural and combustion-related sources. PBM_2.5 exhibited elevated concentrations (1.0–1.4 ng m⁻³) under westerly winds (~3 m s⁻¹), indicating inputs from traffic, shipping, and light industries, while PBM_2.5–10 (0.5–1.1 μg m⁻³) was strongly linked to coal-handling activities at QHD port and soil resuspension. Backward trajectory analysis showed continental air masses dominated in winter (53–100%) and maritime air masses in summer (30–50%), whereas high Hg/Na ratios in PM_2.5 (3.22 × 10⁻⁴) and PM_2.5–10 (2.17 × 10⁻⁴), far exceeding typical marine aerosol values (10⁻⁷–10⁻⁵), indicated negligible marine contributions to PBM. These findings provide new insights into the processes driving mercury pollution in coastal urban environments and highlight the critical role of port-related activities in regional mercury management. Full article

This work describes a simple and economical electrochemical route for the generation of mesoporous alumina (MA) particles that can serve as containers for corrosion inhibitors for the active corrosion protection elements of metals when dispersed in organic coatings. The synthesis of precursor slurries was carried out in an electrochemical reactor with aluminum electrodes operating alternately as anodes and cathodes to facilitate metal dissolution and prevent passivation of the electrode surface. The obtained slurries were thermally treated to produce mesoporous alumina particles with adsorbent characteristics suitable for loading corrosion inhibitors. Benzotriazole (BTA) and 8-hydroxyquinoline (8HQ) were chosen as corrosion inhibitors. Dispersed in a commercial polymer matrix and applied to the coating of mild steel samples, the loaded MA improved the corrosion resistance of the coated metal exposed to a simulated marine environment. When physical damage is intentionally caused to expose the underlying metal, the polymer matrix containing BTA-loaded alumina particles retards the corrosion process due to the swelling of the inhibitor from the particles to the exposed bare metal in the scratch. Electrochemical impedance spectroscopy (EIS) measurements showed a marked increase in low-frequency impedance in coatings containing alumina particles, with the BTA-loaded system providing the most durable protection over extended immersion times (with a 50% improvement in corrosion resistance of steel exposed within the scratch). This demonstrates the potential of this approach for long-term corrosion protection applications. Full article

Electronic devices with polyurethane electronic packaging have been stored in Chinese tropical marine atmosphere environments for 10 years. The long-term natural aging mechanism was studied by comparing the appearance inspection, molecular structure, elemental content, and chemical functional groups of the surface and interior of polyurethane electronic potting. The results indicated that, despite evident chemical aging and physical changes in the encapsulant material, it continued to effectively protect the internal electronic devices, maintaining their performance within an acceptable range. The interior polyurethane potting of electronic devices was white, but the surface turned yellow with noticeable color change. On the surface, the content of tolylene diisocyanate was greatly decreased. The peak heights of the internal carbamate groups located at 1708 cm⁻¹ and 1529 cm⁻¹ were significantly higher than those at the surface. In addition, the internal C element content for the carbamate group at 289.5 eV was higher than that of the surface. It can be inferred that, under ambient temperature and trace oxygen conditions, the urethane groups on the polyurethane electronic potting surface undergo aging reactions. These groups slowly oxidize into the quinoid structure of the chromophore, causing the surface to turn yellow. Despite this discoloration, the potting still protects electronic devices. Therefore, polyurethane electronic potting is ideal for the long-term sealed storage of electronic devices. Full article

Multiple ironstone beds formed during the Callovian-Oxfordian times as a consequence of intense continental weathering, upwelling, and hydrothermal activity. This study examines the compositional differences between core and rim, and the origin of iron ooids along the northwestern margin of the Neo-Tethys Ocean to highlight sea-level fluctuations, redox conditions, and elemental influx. An integrated sedimentological study, including petrography, mineralogy, micro-texture, and mineral chemistry, was carried out to explain the origin and implications of ironstones. The ~14 m thick Callovian-Oxfordian, marginal marine deposits in the Kutch Basin, in western India, exhibit iron ooids, predominantly formed in oolitic shoals during transgression, associated with lagoonal siliciclastics. Callovian shoals interbedded with lagoonal facies record minor sea-level fluctuations, whereas the Oxfordian deposit records a major transgression and condensation, resulting in extensive ironstone deposits. The ooid cortices and nuclei exhibit distinctive mineralogy and micro-textures: glauconitic smectite exhibits poorly-developed rosettes, chamosite displays flower-like, and goethite shows rod-like features. Three types of ooids are formed: (i) monomineralic ooids are entirely of chamosite or goethite, (ii) quartz-nucleated ooids, and (iii) composite ooids with either chamosite core and goethite rim, or chamosite core and glauconitic smectite rim. The assemblages within iron ooids reflect variation in depositional redox conditions: glauconitic smectite develops under suboxic lagoonal flank, chamosite forms in anoxic central lagoon, and goethite precipitates on oxic shoals. Full article

Marine Spatial Planning (MSP) has emerged globally as a governance tool to balance marine conservation and blue economy objectives. While many studies have described the legal and institutional frameworks underpinning MSP, fewer have critically assessed the role of non-governmental organizations (NGOs) in monitoring and evaluation (M&E). This paper integrates a cross-national comparative analysis (Australia, Germany, Seychelles, and England) with a systematic review of the MSP governance literature (2010–2024) to assess how NGO involvement enhances MSP effectiveness. By performing a systematic literature review mapping of 70 peer-reviewed studies, we identify common governance elements and evaluate their links to reported ecological, social, and institutional outcomes. Results show that MSP systems with formal NGO participation—such as Seychelles’ debt-swap initiative and England’s co-managed conservation zones—exhibit higher levels of stakeholder legitimacy and adaptive monitoring. In contrast, centralized systems with limited NGO integration (e.g., Germany) face implementation fragmentation. These findings demonstrate that NGOs play a critical role in strengthening M&E, building cross-scalar coordination, and ensuring policy legitimacy. The study contributes novel insights into the predictive and comparative dimensions of NGO-led MSP frameworks, bridging descriptive governance analysis with outcome-based effectiveness. This study finds that Seychelles’ MSP demonstrates how NGO co-leadership can deliver both ecological and social benefits, while Germany’s federal fragmentation limits effective NGO institutionalization. Australia illustrates the value of integrating NGOs into scientific monitoring, whereas England shows partial but constrained NGO participation in statutory processes. These cross-national findings highlight NGO integration as a key predictor of effective and legitimate MSP outcomes. Full article

Marine-derived Actinomycetota have emerged as promising sources of bioactive natural products, particularly filamentous actinomycetes (e.g., Streptomyces). However, members from non-filamentous genera have showed potential biotechnological importance. In this study, we performed a comprehensive genomic characterization of two bioactive Brevibacterium strains, Brevibacterium luteolum (B. luteolum) 26C and Brevibacterium casei (B. casei) 13A, isolated from two Red Sea sponges. Whole-genome sequencing and taxonomic analysis confirmed species-level identification, marking the first documented report of these species within the Red Sea ecosystem. The two strains displayed antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans. Additionally, functional annotation revealed multiple genomic islands (GIs) enriched with genes conferring heavy metal resistance, DNA repair enzymes, nutrient acquisition, and mobile genetic elements, highlighting potential evolutionary adaptations to the harsh physicochemical conditions of the Red Sea. Genome mining identified biosynthetic gene clusters, including those encoding ε-poly-L-lysine, tropodithietic acid, ectoine, and carotenoids. The comparative analysis of orthologous gene clusters from both strains and their counterparts from terrestrial ecosystems highlighted potential marine adaptive genetic mechanisms. This study highlights the biosynthetic potential of B. luteolum 26C and B. casei 13A and their ecological role as active competitors and potential defensive associates within the sponge microbiome. Full article

Ti80 alloy is one of the most commonly used marine titanium alloys but faces cold cracking risks in thick plate welding. Understanding the relationship between restraint intensity and welding residual stress is critical for industrial applications. This study employs finite element methods to quantify the restraint intensity of Lehigh specimens and establish its quantitative link with welding residual stress in Ti80 alloy. Simulations reveal that restraint intensity increases linearly with plate thickness and decreases linearly with slot depth. A binary linear regression model accurately predicts restraint intensity with relative error of less than 6%. Furthermore, welding simulations demonstrate that residual stress on the weld bead’s upper surface increases exponentially with restraint intensity, while the lower surface shows a linear increase. Exponential and linear fits were applied to predict residual stress on the upper and lower surface, respectively. Validation confirms prediction errors for residual stress are below 9%. This work provides a methodology to assess cracking susceptibility and residual stress in actual Ti80 components by matching restraint conditions with Lehigh specimens. Full article

Piles are common support elements for marine and coastal structures. The scour around pile foundations caused by currents is a major threat to the stability and safety of these structures. The empirical equations commonly used for estimating the equilibrium scour depth around pile groups are limited in their predicative capability, especially when the current approaches the pile group at an angle. This study applies a Multi-Layer Perceptron Backpropagation (MLP/BP) neural network to develop a general model for predicting the local maximum equilibrium scour depth around pile groups in steady currents. The input parameters for the model include all relevant non-dimensional hydrodynamic and structural variables taking full account of the effects of the pile group arrangement and its orientation relative to the approaching current. The model’s performance was evaluated by comparing its predictions against those generated by multiple other machine learning methods, as well as against results from widely used empirical formulas. A comprehensive sensitivity analysis is carried out to determine the importance ranking of the input parameters on model accuracy. Full article

Lubricating oil reflects mechanical component aging and wear. Accurate quantification of its wear metals is essential for equipment safety and intelligent maintenance. This study introduces a rapid, non-destructive method for detecting wear metal content in lubricating oil using hyperspectral technology to overcome limitations such as bulky, expensive instruments and destructive testing in current spectroscopic techniques. Absorption spectra of 98 marine gearbox oil samples were acquired using Hach UV-Vis and GLT optical fiber spectrometers. We propose a multi-head attention mechanism enhanced genetic algorithm (MHA-GA) for deep feature extraction, integrating attention weights into band selection and fitness evaluation to identify key features under multi-element interference. Wear metal prediction models were constructed using random forest (RF), support vector regression (SVR), and extreme gradient boosting (XGBoost). Results demonstrate MHA-GA outperformed traditional genetic algorithm (GA) and competitive adaptive reweighted sampling (CARS) in feature selection. The MHA-GA-XGBoost model performed best. Fe prediction R² reached 0.96 (Hach) and 0.93 (GLT), with RPDs of 5.33 and 3.90. For Cu, R² reached 0.91 and 0.83, with RPDs of 3.35 and 2.42. The results indicate that hyperspectral technology combined with machine learning enables effective non-destructive wear metal quantification, offering a promising strategy for intelligent maintenance and condition monitoring of lubricating oil. Full article