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Search Results (1,478)

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Keywords = metals mobility

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15 pages, 4167 KiB  
Article
Effects of Graphene Quantum Dots on Thermal Properties of Epoxy Using Molecular Dynamics
by Swapnil S. Bamane and Ozgur Keles
Appl. Nano 2025, 6(3), 15; https://doi.org/10.3390/applnano6030015 - 20 Aug 2025
Abstract
Polymer matrix composites (PMCs) are crucial for their applications in aerospace, electronics, defense, and structural materials. PMCs reinforced with nanofillers offer substantial potential for enhanced thermal and mechanical performance. Although there have been significant developments in nanofiller-based high-performance composites involving graphene, carbon nanotubes, [...] Read more.
Polymer matrix composites (PMCs) are crucial for their applications in aerospace, electronics, defense, and structural materials. PMCs reinforced with nanofillers offer substantial potential for enhanced thermal and mechanical performance. Although there have been significant developments in nanofiller-based high-performance composites involving graphene, carbon nanotubes, and metal oxides, the smallest of all the fillers, the graphene quantum dot (GQD), has not been explored thoroughly. The objective of this study is to investigate the effects of GQDs on the thermal properties of epoxy nanocomposites using all-atom molecular dynamics (MD) simulations. Specifically, the influence of GQDs on the glass transition temperature (Tg) and coefficient of linear thermal expansion (CTE) of the bisphenol F epoxy is evaluated. Further, the effects of surface functionalization and edge functionalization of GQDs are analyzed. Results demonstrate that the inclusion of functionalized GQDs leads to a 16% improvement in Tg, attributed to enhanced interfacial interactions and restricted molecular mobility in the epoxy network. MD simulations reveal that functional groups on GQDs form strong physical and chemical interactions with the polymer matrix, effectively altering its dynamics at the Tg. These results provide key molecular-level insights into the design of the next generation of thermally stable epoxy nanocomposites for high-performance applications in aerospace and defense. Full article
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26 pages, 8002 KiB  
Article
Functional Genomic Characteristics of Marine Sponge-Associated Microbulbifer spongiae MI-GT
by Nabila Ishaq, Qianqian Song, Micha Ilan and Zhiyong Li
Microorganisms 2025, 13(8), 1940; https://doi.org/10.3390/microorganisms13081940 - 20 Aug 2025
Abstract
The genus Microbulbifer comprises a group of marine, gram-negative bacteria known for their remarkable ability to adapt to a variety of environments. Therefore, this study aimed to investigate the genetic diversity and metabolic characteristics of M. spongiae MI-GT and three Microbulbifer reference [...] Read more.
The genus Microbulbifer comprises a group of marine, gram-negative bacteria known for their remarkable ability to adapt to a variety of environments. Therefore, this study aimed to investigate the genetic diversity and metabolic characteristics of M. spongiae MI-GT and three Microbulbifer reference strains by genomic and comparative genomic analysis. Compared to free-living reference strains, the lower GC content, higher number of strain-specific genes, pseudogenes, unique paralogs, dispensable genes, and mobile gene elements (MGEs) such as genomic islands (GIs) and insertion sequence (IS) elements, while the least number of CAZymes, indicates that M. spongiae MI-GT may be a facultative sponge-symbiont. Comparative genomic analysis indicates that M. spongiae MI-GT possesses a plasmid and a higher number of strain-specific genes than Microbulbifer reference strains, showing that M. spongiae MI-GT may have acquired unique genes to adapt sponge-host environment. Moreover, there are differences in the functional distribution of genes belonging to different COG-classes in four Microbulbifer strains. COG-functional analysis reveals a lower number of strain-specific genes associated with metabolism, energy production, and motility in M. spongiae MI-GT compared to Microbulbifer reference strains, suggesting that sponge-associated lifestyle may force this bacterium to acquire nutrients from the sponge host and loss motility genes. Finally, we found that several proteins associated with oxidative stress response (sodC, katA, catA, bcp, trmH, cspA), osmotic stress response (dsbG, ampG, amiD_2, czcA, czcB, and corA), and tolerance to biotoxic metal proteins (dsbG, ampG, amiD_2, czcA, czcB, and corA) are absent in M. spongiae MI-GT but present in Microbulbifer reference strains, indicating that M. spongiae MI-GT live in a stable and less stress environment provided by the sponge host than free-living Microbulbifer strains. Our results suggest M. spongiae MI-GT exhibits gene characteristics related to its adaptation to the sponge host habitat, meanwhile reflecting its evolution towards a sponge-associated lifestyle. Full article
(This article belongs to the Special Issue State-of-the-Art Environmental Microbiology in China 2025)
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27 pages, 7563 KiB  
Article
Evaluation of the Dynamic Behavior and Vibrations of the Operator-Vehicle Assembly in Electric Agricultural Tractor Operations: A Simulation Approach for Sustainable Transport Systems
by Teofil-Alin Oncescu, Ilona Madalina Costea, Ștefan Constantin Burciu and Cristian Alexandru Rentea
Systems 2025, 13(8), 710; https://doi.org/10.3390/systems13080710 - 18 Aug 2025
Abstract
This study presents an advanced simulation-based methodology for evaluating the dynamic vibrational behavior of the operator–vehicle assembly in autonomous electric agricultural tractors. Using the TE-0 electric tractor as the experimental platform, the research is structured into three integrated stages. In the first stage, [...] Read more.
This study presents an advanced simulation-based methodology for evaluating the dynamic vibrational behavior of the operator–vehicle assembly in autonomous electric agricultural tractors. Using the TE-0 electric tractor as the experimental platform, the research is structured into three integrated stages. In the first stage, a seated anthropometric virtual model of the human operator is developed based on experimental data and biomechanical validation. The second stage involves a detailed modal analysis of the TE-0 electric tractor using Altair Sim Solid, with the objective of determining the natural frequencies and vibration modes in the [0–80] Hz range, in compliance with ISO 2631-1. This analysis captures both the structural-induced frequencies—associated with the chassis, wheelbase, and metallic frame—and the operational-induced frequencies, influenced by the velocity and terrain profile. Subsequently, the modal analysis of the “Grammer Cabin Seat” is conducted to assess its dynamic response and identify critical vibration modes, highlighting how the seat behaves under vibrational stimuli from the tractor and terrain. The third stage extends the analysis to the virtual operator model seated on the tractor seat, investigating the biomechanical response of the human body and the operator–seat–vehicle interaction during simulated motion. Simulations were carried out using SolidWorks 2023 and Altair Sim Solid over a frequency range of [0–80] Hz, corresponding to operation on unprocessed soil covered with grass, at a constant forward speed of 7 km/h. The results reveal critical resonance modes and vibration transmission paths that may impact operator health, comfort, and system performance. The research contributes to the development of safer, more ergonomic, and sustainable autonomous agricultural transport systems. By simulating real-world operation scenarios and integrating a rigorously validated experimental protocol—including vibration data acquisition, biomechanical modeling, and multi-stage modal analysis—this study demonstrates the importance of advanced modeling in optimizing system-level performance, minimizing harmful vibrations, and supporting the transition toward resilient and eco-efficient electric tractor platforms in smart agricultural mobility. Full article
(This article belongs to the Section Systems Practice in Social Science)
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15 pages, 1048 KiB  
Article
Genomic Characterization of Multidrug-Resistant and ESBL-Producing Klebsiella pneumoniae Isolated from Healthy Rabbits Intended for Human Consumption
by Vanessa Silva, Manuela Caniça, Rani Rivière, Adriana Silva, Patrícia Poeta and Gilberto Igrejas
Microorganisms 2025, 13(8), 1931; https://doi.org/10.3390/microorganisms13081931 - 18 Aug 2025
Abstract
Klebsiella pneumoniae is an important pathogen associated with multidrug resistance and virulence in both human and animal populations. While its prevalence and resistance patterns are well documented in clinical settings, data on K. pneumoniae in food-producing animals remain scarce. This study aimed to [...] Read more.
Klebsiella pneumoniae is an important pathogen associated with multidrug resistance and virulence in both human and animal populations. While its prevalence and resistance patterns are well documented in clinical settings, data on K. pneumoniae in food-producing animals remain scarce. This study aimed to isolate and characterize multidrug-resistant K. pneumoniae strains from healthy rabbits raised for human consumption, with a focus on antimicrobial resistance genes, plasmid content, and associated mobile genetic elements. A total of 295 fecal samples were collected from rabbits across 20 commercial farms in northern Portugal. Isolates were confirmed using MALDI-TOF MS, tested for hypermucoviscosity, and subjected to antimicrobial susceptibility testing (EUCAST). Whole-genome sequencing (WGS) was performed to determine sequence types (STs), resistance genes, plasmids, and resistance determinants for metals and biocides. Six K. pneumoniae isolates were recovered, showing extensive antimicrobial resistance profiles, including ESBL genes such as blaCTX-M-15, blaSHV-28, and blaTEM-1. The most frequent ST was ST307. Multiple genes resistant to heavy metals were identified. Plasmid analysis revealed the presence of IncFII, IncN, and ColRNAI types. Network analysis showed clusters of genetically related isolates and highlighted shared resistance mechanisms. The presence of multidrug-resistant K. pneumoniae in healthy rabbits destined for human consumption underscores the zoonotic potential of this species and the need for surveillance in the animal–food–human interface. These findings contribute to a better understanding of resistance ecology in the context of One Health. Full article
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22 pages, 767 KiB  
Article
Leachability and Health Risk Assessment of Cadmium and Other Heavy Metals in Agricultural Soils from the Mae Tao Watershed, Northern Thailand
by Nipada Santha, Thanan Watcharamai, Rungroj Benjakul and Schradh Saenton
Toxics 2025, 13(8), 687; https://doi.org/10.3390/toxics13080687 - 18 Aug 2025
Abstract
Decades of unregulated zinc mining activities in the Mae Tao watershed, located in Mae Sot District, Tak Province, northern Thailand, have resulted in the pervasive contamination of agricultural soils with heavy metals, particularly cadmium (Cd), zinc (Zn), lead (Pb), and manganese (Mn). This [...] Read more.
Decades of unregulated zinc mining activities in the Mae Tao watershed, located in Mae Sot District, Tak Province, northern Thailand, have resulted in the pervasive contamination of agricultural soils with heavy metals, particularly cadmium (Cd), zinc (Zn), lead (Pb), and manganese (Mn). This legacy pollution has significantly impacted multiple environmental compartments—including surface water, groundwater, and sediments—and poses chronic health risks to local populations. This study investigates the key geochemical and physicochemical factors governing the leachability and mobility of these metals from contaminated soils and evaluates the associated human health risks. Controlled leaching experiments demonstrated that ionic strength exerts a more pronounced influence on metal mobilization than pH or other tested variables, suggesting that the electrolyte composition of pore water plays a dominant role in heavy metal transport. Despite elevated total concentrations of Cd, Zn, Pb, and Mn in the soils, hazard quotient (HQ) calculations indicated no significant non-carcinogenic risk under typical exposure scenarios. However, Cd exhibited a carcinogenic risk above the acceptable threshold at both average and peak soil concentrations, underscoring its potential to adversely affect human health. These findings enhance the understanding of heavy metal behavior in contaminated agroecosystems and provide a scientific basis for targeted risk management and long-term monitoring strategies in the Mae Sot region. Full article
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40 pages, 7071 KiB  
Review
Electrical Properties of Composite Materials: A Comprehensive Review
by Thomaz Jacintho Lopes, Ary Machado de Azevedo, Sergio Neves Monteiro and Fernando Manuel Araujo-Moreira
J. Compos. Sci. 2025, 9(8), 438; https://doi.org/10.3390/jcs9080438 - 15 Aug 2025
Viewed by 357
Abstract
Conductive composites are a flexible class of engineered materials that combine conductive fillers with an insulating matrix—usually made of ceramic, polymeric, or a hybrid material—to customize a system’s electrical performance. By providing tunable electrical properties in addition to benefits like low density, mechanical [...] Read more.
Conductive composites are a flexible class of engineered materials that combine conductive fillers with an insulating matrix—usually made of ceramic, polymeric, or a hybrid material—to customize a system’s electrical performance. By providing tunable electrical properties in addition to benefits like low density, mechanical flexibility, and processability, these materials are intended to fill the gap between conventional insulators and conductors. The increasing need for advanced technologies, such as energy storage devices, sensors, flexible electronics, and biomedical interfaces, has significantly accelerated their development. The electrical characteristics of composite materials, including metallic, ceramic, polymeric, and nanostructured systems, are thoroughly examined in this review. The impact of various reinforcement phases—such as ceramic fillers, carbon-based nanomaterials, and metallic nanoparticles—on the electrical conductivity and dielectric behavior of composites is highlighted. In addition to conduction models like correlated barrier hopping and Debye relaxation, the study investigates mechanisms like percolation thresholds, interfacial polarization, and electron/hole mobility. Because of the creation of conductive pathways and improved charge transport, developments in nanocomposite engineering, especially with regard to graphene derivatives and silver nanoparticles, have shown notable improvements in electrical performance. This work covers the theoretical underpinnings and physical principles of conductivity and permittivity in composites, as well as experimental approaches, characterization methods (such as SEM, AFM, and impedance spectroscopy), and real-world applications in fields like biomedical devices, sensors, energy storage, and electronics. This review provides important insights for researchers who want to create and modify multifunctional composite materials with improved electrical properties by bridging basic theory with technological applications. Full article
(This article belongs to the Special Issue Optical–Electric–Magnetic Multifunctional Composite Materials)
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21 pages, 980 KiB  
Article
Remediation of Heavy Metal-Contaminated Soils Using Phosphate-Enriched Sewage Sludge Biochar
by Protogene Mbasabire, Yves Theoneste Murindangabo, Jakub Brom, Protegene Byukusenge, Jean de Dieu Marcel Ufitikirezi, Josine Uwihanganye, Sandra Nicole Umurungi, Marie Grace Ntezimana, Karim Karimunda and Roger Bwimba
Sustainability 2025, 17(16), 7345; https://doi.org/10.3390/su17167345 - 14 Aug 2025
Viewed by 335
Abstract
Heavy metals represent long-lasting contaminants that pose significant risks to both human health and ecosystem integrity. Originating from both natural and anthropogenic activities, they bioaccumulate in organisms through the food web, leading to widespread and long-lasting contamination. Industrialization, agriculture, and urbanization have exacerbated [...] Read more.
Heavy metals represent long-lasting contaminants that pose significant risks to both human health and ecosystem integrity. Originating from both natural and anthropogenic activities, they bioaccumulate in organisms through the food web, leading to widespread and long-lasting contamination. Industrialization, agriculture, and urbanization have exacerbated soil and water contamination through activities such as mining, industrial production, and wastewater use. In response to this challenge, biochar produced from waste materials such as sewage sludge has emerged as a promising remediation strategy, offering a cost-effective and sustainable means to immobilize heavy metals and reduce their bioavailability in contaminated environments. Here we explore the potential of phosphate-enriched biochar, derived from sewage sludge, to adsorb and stabilize heavy metals in polluted soils. Sewage sludge was pyrolyzed at various temperatures to produce biochar. A soil incubation experiment was conducted by adding phosphate-amended biochar to contaminated soil and maintaining it for one month. Heavy metals were extracted using a CaCl2 extraction method and analyzed using atomic absorption spectrophotometry. Results demonstrated that phosphate amendment significantly enhanced the biochar’s capacity to immobilize heavy metals. Amending soils with 2.5 wt% phosphate-enriched sewage sludge biochar led to reductions in bioavailable Cd (by 65–82%), Zn (40–75%), and Pb (52–88%) across varying pyrolysis temperatures. Specifically, phosphate-amended biochar reduced the mobility of Cd and Zn more effectively than unamended biochar, with a significant decrease in their concentrations in soil extracts. For Cu and Pb, the effectiveness varied with pyrolysis temperature and phosphate amendment, highlighting the importance of optimization for specific metal contaminants. Biochar generated from elevated pyrolysis temperatures (500 °C) showed an increase in ash content and pH, which improved their ability to retain heavy metals and limit their mobility. These findings suggest that phosphate-amended biochar reduces heavy metal bioavailability, minimizing their entry into the food chain. This supports a sustainable approach for managing hazardous waste and remediating contaminated soils, safeguarding ecosystem health, and mitigating public health risks. Full article
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21 pages, 1559 KiB  
Article
Diffusiophoresis of a Conducting Liquid Metal Droplet (LMD) in a Cylindrical Pore
by Sunny Chen, Lily Chuang, Nemo Chang, Jean Chien, Venesa Liao and Eric Lee
Molecules 2025, 30(16), 3372; https://doi.org/10.3390/molecules30163372 - 13 Aug 2025
Viewed by 201
Abstract
Diffusiophoresis of a liquid metal droplet (LMD) in a cylindrical pore is investigated theoretically in this study. A patched pseudo-spectral method based on Chebyshev polynomials combined with a geometric mapping technique is adopted to solve the resulting governing electrokinetic equations in irregular geometries. [...] Read more.
Diffusiophoresis of a liquid metal droplet (LMD) in a cylindrical pore is investigated theoretically in this study. A patched pseudo-spectral method based on Chebyshev polynomials combined with a geometric mapping technique is adopted to solve the resulting governing electrokinetic equations in irregular geometries. Several interesting phenomena are found which provide useful guidelines in practical applications involving liquid metal droplets (LMDs) such as drug delivery. In particular, the severe boundary confinement effect brings about unique features of droplet motion, leading to mobility reversal and a “stagnation phenomenon” where droplets cease to move regardless of their surface charge densities in a narrow cylindrical pore. An overwhelming exterior vortex flow nearly enclosing the entire droplet is found to be responsible for this. This finds various practical applications in droplet microfluidics and drug delivery. For instance, a cylindrical pore or blood vessel may be clogged by a droplet much smaller than its radius. In addition, the “solidification phenomenon”, where all droplets move with identical speed regardless of their viscosities like rigid particles with no interior recirculating vortex flows, is also discovered. The electrokinetic mechanism behind it and its potential applications are discussed. Overall, the geometric configuration considered here is a classic one, with many other possible applications yet to be found by experimental researchers and engineers in the field of colloid industry and operations. Full article
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16 pages, 1838 KiB  
Article
Nano-Thin Oxide Layers Formed on Hydrogen Plasma Modified Crystalline Si for Advanced Applications
by Sashka Alexandrova, Anna Szekeres and Evgenia Valcheva
Nanomanufacturing 2025, 5(3), 12; https://doi.org/10.3390/nanomanufacturing5030012 - 12 Aug 2025
Viewed by 205
Abstract
Since the early days of silicon manufacturing, hydrogen gas treatment has been used to control the defect concentrations. Its beneficial effect can be enhanced using hydrogen plasma as a source of active atomic hydrogen. Hydrogen plasma modification of c-Si surface can be challenging [...] Read more.
Since the early days of silicon manufacturing, hydrogen gas treatment has been used to control the defect concentrations. Its beneficial effect can be enhanced using hydrogen plasma as a source of active atomic hydrogen. Hydrogen plasma modification of c-Si surface can be challenging because the plasma can induce precursors of defect centers that can persist at the interface and/or grown oxide after subsequent thermal oxidation. In the present study, we investigate nanoscale silicon dioxides with thicknesses in the range of 6–22 nm grown at low temperature (850 °C) in dry oxygen on radio frequency (RF) hydrogen plasma-treated silicon surface. The properties of these oxides are compared to oxides grown following standard Radio Corporation of America (RCA) Si technology. Electroreflectance measurements reveal better interface quality with enhanced electron mobility and lowered oxidation-induced stress levels when the oxides are grown on H-plasma modified c-Si substrates. These results are in good accordance with the reduced defect concentration established from the analysis of the current–voltage (I-V) and multifrequency capacitance–voltage (C-V) characteristics of metal-oxide-semiconductor (MOS) capacitors incorporating the Si-SiO2 structures. The study proves the potential of hydrogen plasma treatment of Si prior to oxidation for various Si-based applications. Full article
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23 pages, 2714 KiB  
Article
Transport Dust in Poland: Tracking the Invisible Footprint of Transport on Ecosystem Health
by Magdalena Wróbel, Joanna Kamińska, Niranjala Dissanayake Mudiyanselage, Kinga Napiórkowska, Gabriela Bauman and Justyna Rybak
Appl. Sci. 2025, 15(16), 8862; https://doi.org/10.3390/app15168862 - 11 Aug 2025
Viewed by 346
Abstract
Urban road dust (URD) is a major source of particulate matter (PM) and pollutants, including trace elements and organic compounds, affecting human health and the environment. This study investigates the chemical composition, toxicity, and environmental transport mechanisms of URD from road and rail [...] Read more.
Urban road dust (URD) is a major source of particulate matter (PM) and pollutants, including trace elements and organic compounds, affecting human health and the environment. This study investigates the chemical composition, toxicity, and environmental transport mechanisms of URD from road and rail systems in two Polish cities. It compares trace element concentrations (e.g., Cu, Zn, Pb), chemical composition, toxicity of road vs. rail dust, and the impact of rainfall on contaminant dispersion. The oral pathway was identified as the main exposure route in both adults and children, followed by that of dermal contact. Railways pose additional challenges due to frequent maintenance and increased PM emissions. Results show that smaller cities like Rawicz may present higher health risks from URD due to local industry (e.g., metal processing) than larger cities like Wrocław. Rainfall mobilizes trace elements in urban dust, increasing pollutant runoff and exposure risks, highlighting the need for better runoff management. The highest road-related pollution was found in Rawicz (S5), with the highest railway-related pollution also found at the Rawicz station. Microtox showed no toxicity in Wrocław URD (except for short-term effect) but higher toxicity in Rawicz. Daphtoxkit showed the highest Daphnia magna mortality near roads (40.0%) in Rawicz. Ostracodtoxkit revealed strong growth inhibition in Wrocław (up to 94.29%). ECR confirmed a higher cancer risk in Rawicz, especially in children (Cr, As). Full article
(This article belongs to the Special Issue Exposure Pathways and Health Implications of Environmental Chemicals)
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16 pages, 2069 KiB  
Article
High-Efficiency Mid-Infrared Transmission Modulator Based on Graphene Plasmon Resonance and Photonic Crystal Defect States
by Jiduo Dong, Qing Zang, Linlong Tang, Binbin Wei, Xiangxing Bai, Hao Zhang, Chunheng Liu, Haofei Shi, Hongyan Shi, Yang Liu and Yueguang Lu
Photonics 2025, 12(8), 800; https://doi.org/10.3390/photonics12080800 - 9 Aug 2025
Viewed by 289
Abstract
With the continuous exploration and advancement of communication frequency bands, terahertz and mid-to-far-infrared communication systems have attracted significant attention in recent years. Modulators are essential components in these systems, making the enhancement of modulator performance in the infrared and terahertz bands a prominent [...] Read more.
With the continuous exploration and advancement of communication frequency bands, terahertz and mid-to-far-infrared communication systems have attracted significant attention in recent years. Modulators are essential components in these systems, making the enhancement of modulator performance in the infrared and terahertz bands a prominent research focus. In this study, we propose a high-performance infrared transmission-type modulator based on the plasmon resonance effect of graphene nanoribbons. This design synergistically exploits near-field enhancement from metal slits and defect states in one-dimensional photonic crystals to strengthen light–graphene interactions. The modulator achieves a modulation depth exceeding 80% and an operating bandwidth greater than 4 THz in the mid-infrared range, enabling efficient signal modulation for free-space optical communication. Importantly, the proposed design alleviates experimental challenges typically associated with the need for high graphene mobility and a wide Fermi energy tuning range in conventional approaches, thereby improving its practical feasibility. Moreover, the approach is scalable to far-infrared and terahertz bands, offering valuable insights for advancing signal modulation technologies across these spectral regions. Full article
(This article belongs to the Special Issue Metamaterials and Nanophotonics: Fundamentals and Applications)
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18 pages, 3363 KiB  
Article
Spatial Heterogeneity of Heavy Metals in Arid Oasis Soils and Its Irrigation Input–Soil Nutrient Coupling Mechanism
by Jiang Liu, Chongbo Li, Jing Wang, Liangliang Li, Junling He and Funian Zhao
Sustainability 2025, 17(15), 7156; https://doi.org/10.3390/su17157156 - 7 Aug 2025
Viewed by 392
Abstract
Soil environmental quality in arid oases is crucial for regional ecological security but faces multi-source heavy metal (HM) contamination risks. This study aimed to (1) characterize the spatial distribution of soil HMs (As, Cd, Cr, Cu, Hg, and Zn) in the Ka Shi [...] Read more.
Soil environmental quality in arid oases is crucial for regional ecological security but faces multi-source heavy metal (HM) contamination risks. This study aimed to (1) characterize the spatial distribution of soil HMs (As, Cd, Cr, Cu, Hg, and Zn) in the Ka Shi gar oasis, Xinjiang, (2) quantify the driving effect of irrigation water, and (3) elucidate interactions between HMs, soil properties, and land use types. Using 591 soil and 12 irrigation water samples, spatial patterns were mapped via inverse distance weighting interpolation, with drivers and interactions analyzed through correlation and land use comparisons. Results revealed significant spatial heterogeneity in HMs with no consistent regional trend: As peaked in arable land (5.27–40.20 μg/g) influenced by parent material and agriculture, Cd posed high ecological risk in gardens (max 0.29 μg/g), and Zn reached exceptional levels (412.00 μg/g) in gardens linked to industry/fertilizers. Irrigation water impacts were HM-specific: water contributed to soil As enrichment, whereas high water Cr did not elevate soil Cr (indicating industrial dominance), and Cd/Cu showed no significant link. Interactions with soil properties were regulated by land use: in arable land, As correlated positively with EC/TN and negatively with pH; in gardens, HMs generally decreased with pH, enhancing mobility risk; in forests, SOM adsorption immobilized HMs; in construction land, Hg correlated with SOM/TP, suggesting industrial-organic synergy. This study advances understanding by demonstrating that HM enrichment arises from natural and anthropogenic factors, with the spatial heterogeneity of irrigation water’s driving effect critically regulated by land use type, providing a spatially explicit basis for targeted pollution control and sustainable oasis management. Full article
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29 pages, 3371 KiB  
Article
The Impact of a Mobile Laboratory on Water Quality Assessment in Remote Areas of Panama
by Jorge E. Olmos Guevara, Kathia Broce, Natasha A. Gómez Zanetti, Dina Henríquez, Christopher Ellis and Yazmin L. Mack-Vergara
Sustainability 2025, 17(15), 7096; https://doi.org/10.3390/su17157096 - 5 Aug 2025
Viewed by 314
Abstract
Monitoring water quality is crucial for achieving clean water and sanitation goals, particularly in remote areas. The project “Morbidity vs. Water Quality for Human Consumption in Tonosí: A Pilot Study” aimed to enhance water quality assessments in Panama using advanced analytical techniques to [...] Read more.
Monitoring water quality is crucial for achieving clean water and sanitation goals, particularly in remote areas. The project “Morbidity vs. Water Quality for Human Consumption in Tonosí: A Pilot Study” aimed to enhance water quality assessments in Panama using advanced analytical techniques to assess volatile organic compounds, heavy metals, and microbiological pathogens. To support this, the Technical Unit for Water Quality (UTECH) was established, featuring a novel mobile laboratory with cutting-edge technology for accurate testing, minimal chemical reagent use, reduced waste generation, and equipped with a solar-powered battery system. The aim of this paper is to explore the design, deployment, and impact of the UTECH. Furthermore, this study presents results from three sampling points in Tonosí, where several parameters exceeded regulatory limits, demonstrating the capabilities of the UTECH and highlighting the need for ongoing monitoring and intervention. The study also assesses the environmental, social, and economic impacts of the UTECH in alignment with the Sustainable Development Goals and national initiatives. Finally, a SWOT analysis illustrates the UTECH’s potential to improve water quality assessments in Panama while identifying areas for sustainable growth. The study showcases the successful integration of advanced mobile laboratory technologies into water quality monitoring, contributing to sustainable development in Panama and offering a replicable model for similar initiatives in other regions. Full article
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22 pages, 7171 KiB  
Article
Distribution Characteristics, Mobility, and Influencing Factors of Heavy Metals at the Sediment–Water Interface in South Dongting Lake
by Xiaohong Fang, Xiangyu Han, Chuanyong Tang, Bo Peng, Qing Peng, Linjie Hu, Yuru Zhong and Shana Shi
Water 2025, 17(15), 2331; https://doi.org/10.3390/w17152331 - 5 Aug 2025
Viewed by 431
Abstract
South Dongting Lake is an essential aquatic ecosystem that receives substantial water inflows from the Xiangjiang and Zishui Rivers. However, it is significantly impacted by human activities, including mining, smelting, and farming. These activities have led to serious contamination of the lake’s sediments [...] Read more.
South Dongting Lake is an essential aquatic ecosystem that receives substantial water inflows from the Xiangjiang and Zishui Rivers. However, it is significantly impacted by human activities, including mining, smelting, and farming. These activities have led to serious contamination of the lake’s sediments with heavy metals (HMs). This study investigated the distribution, mobility, and influencing factors of HMs at the sediment–water interface. To this end, sediment samples were analyzed from three key regions (Xiangjiang River estuary, Zishui River estuary, and northeastern South Dongting Lake) using traditional sampling methods and Diffusive Gradients in Thin Films (DGT) technology. Analysis of fifteen HMs (Pb, Bi, Ni, As, Se, Cd, Sb, Mn, Zn, V, Cr, Cu, Tl, Co, and Fe) revealed significant spatial heterogeneity. The results showed that Cr, Cu, Pb, Bi, Ni, As, Se, Cd, Sb, Mn, Zn, and Fe exhibited high variability (CV > 0.20), whereas V, Tl, and Co demonstrated stable concentrations (CV < 0.20). Concentrations were found to exceed background values of the upper continental crust of eastern China (UCC), Yangtze River sediments (YZ), and Dongting Lake sediments (DT), particularly at the Xiangjiang estuary (XE) and in the northeastern regions. Speciation analysis revealed that V, Cr, Cu, Ni, and As were predominantly found in the residual fraction (F4), while Pb and Co were concentrated in the oxidizable fraction (F3), Mn and Zn appeared primarily in the exchangeable fractions (F1 and F2), and Cd was notably dominant in the exchangeable fraction (F1), suggesting a high potential for mobility. Additionally, DGT results confirmed a significant potential for the release of Pb, Zn, and Cd. Contamination assessment using the Pollution Load Index (PLI) and Geoaccumulation Index (Igeo) identified Pb, Bi, Ni, As, Se, Cd, and Sb as major pollutants. Among these, Bi and Cd were found to pose the highest risks. Furthermore, the Risk Assessment Code (RAC) and the Potential Ecological Risk Index (PERI) highlighted Cd as the primary ecological risk contributor, especially in the XE. The study identified sediment grain size, pH, electrical conductivity, and nutrient levels as the primary influencing factors. The PMF modeling revealed HM sources as mixed smelting/natural inputs, agricultural activities, natural weathering, and mining/smelting operations, suggesting that remediation should prioritize Cd control in the XE with emphasis on external inputs. Full article
(This article belongs to the Section Water Quality and Contamination)
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16 pages, 2634 KiB  
Article
Optimized SILAR Growth of Vertically Aligned ZnO Nanorods for Low-Temperature Acetone Detection
by Brahim Ydir, Amine Ajdour, Mouad Soumane, Iulia Antohe, Gabriel Socol, Luiza-Izabela Toderascu, Driss Saadaoui, Imade Choulli, Radouane Leghrib and Houda Lahlou
Chemosensors 2025, 13(8), 289; https://doi.org/10.3390/chemosensors13080289 - 5 Aug 2025
Viewed by 374
Abstract
Vertically oriented morphologies of the semiconducting metal oxide (SMO) surface provide a simple and effective means of enhancing gas sensor performance. We successfully synthesized explicitly aligned ZnO nanorods using a simple automated SILAR technique to improve acetone detection. In this work, we found [...] Read more.
Vertically oriented morphologies of the semiconducting metal oxide (SMO) surface provide a simple and effective means of enhancing gas sensor performance. We successfully synthesized explicitly aligned ZnO nanorods using a simple automated SILAR technique to improve acetone detection. In this work, we found that vertically oriented morphologies, such as well-aligned ZnO nanorods, can significantly enhance the sensor response due to an increase in specific active area and electron mobility, allowing a faster response to changes in the gas environment. The optimal operating temperature for our ZnO nanorod-based sensors in detecting acetone gas is 260 °C. At this temperature, the sensors exhibit a 96% response with a rapid response time of just 3 s. The improved sensing performance is attributed to both electronic and chemical sensitization mechanisms, which enhance the formation of active sites and shorten electron diffusion paths. Full article
(This article belongs to the Special Issue Functionalized Material-Based Gas Sensing)
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