Search Results (1,061)

Semiconducting clathrates are a distinct class of inclusion compounds with considerable interest for thermoelectric applications. We report here the synthesis, crystal structure and thermoelectric properties of Sn₃₈Sb₈I₈. The compound was synthesized via planetary ball milling of the corresponding elements for 6 h and then sintering of amorphous mixture at 620 K for 3 days. The crystal structure of the polycrystalline product was determined via X-ray powder diffraction and Rietveld refinement as a type-I clathrate (a = 12.0390(2), space group Pm-3n, No. 223) with mixed-occupied Sn/Sb framework sites and fully occupied I guest sites. Further analysis on the chemical composition, nanomorphology and vibrational modes of the material was carried out via Induced-Coupled-Plasma–Mass Spectrometry, SEM/EDX microscopy and Raman spectroscopy, respectively. Thermoelectric measurements were performed on hot-pressed samples with ca. 98% of the crystallographic density. The clathrate compound behaves as an n-type semiconductor with a band gap of 0.737 eV and exhibits a maximum ZT of 0.0016 at 473 K. Theoretical calculations on the formation enthalpy, electron density of states and transport properties provide insights into the experimentally observed physical behavior. Full article

The erodibility of natural cohesive sediments and artificial mixtures was investigated through controlled laboratory experiments and used as a basis to discuss seabed mobility and suspended particulate matter on the Continental Shelf adjacent to a river mouth. Changes in the erodibility of cohesive seabeds can influence resuspension and erosion rates and impact suspended particulate matter dispersion patterns and even the benthic community. For the experiments, sediment samples with sand content ranging from 0% to 90% were tested using an erosion testing chamber to evaluate the relationships among sand content, settling, consolidation, critical shear stress, and erosion rate. Critical shear stress values ranged from 0.31 to 0.42 N/m², and erosion rates varied up to 30 times between the most mud-rich and sand-rich samples. Natural samples exhibited lower erodibility, evidenced by higher critical shear stress and lower erosion rates compared to Industrial Clay, highlighting the role of organic matter in enhancing sediment stability. Additionally, although the sand addition reduced the critical shear stress required for sediment motion, it resulted in lower erosion rates. Results were also compared with sediment samples collected from the Continental Shelf adjacent to the Doce River mouth, a region impacted by a large-scale mining tailings spill in 2015. Although the frequency of sediment mobilization did not differ significantly between pre- and post-disaster conditions, mud-rich sediments exhibited greater erosion potential once the threshold was surpassed. This suggests that the dam failure impacted the sediment dynamics of the Continental Shelf adjacent to the Doce River mouth. These findings can be used to improve sediment transport models and environmental management strategies in disturbed coastal systems. Full article

Sustainable management of Construction and Demolition Waste (CDW) is key to the Circular Economy. Reusing crushed concrete as recycled concrete aggregates (RCAs) in hot-mix asphalt (HMA) is a viable CDW solution, although RCA’s high absorption can affect performance. This study evaluates the effect of partially replacing 0%, 10%, and 30% of virgin aggregate with RCA in a dense-graded HMA, assessing its moisture susceptibility and cracking resistance. Specimens were subjected to long-term water-immersion aging (3 and 6 months at 25 °C) and tested for Indirect Tensile Strength (ITS), Tensile Strength Ratio (TSR), and Cracking Tolerance Index (CT-index). RCA incorporation consistently increased ITS at all aging levels. In particular, the 30% RCA mixtures exhibited the highest strength, exceeding the absolute ITS thresholds required by various U.S. transportation agencies to ensure structural capacity. While TSR values remained below the 80% AASHTO T 283 threshold, 10% and 30% RCA mixes had higher TSR than the control, indicating a comparative improvement in moisture resistance. Conversely, the CT-index decreased with more RCA and longer immersion, particularly at 30% RCA, revealing a trade-off between strength gain and cracking tolerance under prolonged wet exposure. Overall, a 10% RCA replacement level provided the most balanced performance, supporting its technical feasibility for sustainable, performance-based mixture design. Full article

Transportation-related greenhouse gas (GHG) emissions in Louisiana have risen significantly, yet the environmental impacts of asphalt mixture production remain underexplored. This study conducted a cradle-to-gate environmental life cycle assessment (LCA) to quantify global warming potential (GWP) for asphalt mixtures produced in Louisiana and establish GWP benchmarks tailored to mixture types. The LCA encompassed material extraction and production, transport to plants, and asphalt mixing, using two datasets: Environmental Product Declarations from the NAPA Eco-label program (21 mixtures) and Job Mix Formulas from the LaPave database at the Louisiana Department of Transportation and Development (DOTD) (207 mixtures). GWP was evaluated using the FHWA LCA Pave tool with TRACI 2.1 factors, and benchmarks were set at the 20th, 40th, 50th percentiles, and the average. Statistical analyses assessed differences across nominal maximum aggregate sizes and traffic levels. Results showed GWP benchmarks from both datasets exceeded U.S. General Services Administration thresholds by an average of 6.5%, with significant variation among mixture types. These findings highlight the need for targeted emission reduction strategies and accurate environmental performance evaluation to promote more sustainable pavement practices and greener infrastructure in Louisiana. Full article

Levan and levan-type fructooligosaccharides (L-FOSs) are non-digestible fructans with prebiotic properties that promote gut microbiota growth. This study presents the first genomic analysis of a Bacillus velezensis HL25 strain with high fructan-producing efficiency, revealing genes involved in sucrose utilization and fructan biosynthesis. A putative levansucrase operon was identified in the HL25 genome, consisting of the sacB levansucrase gene classified in GH68 subfamily 1 and the following three GH32 genes: endo-levanase (lev), β-fructofuranosidase (ffase), and sucrose-6-phosphate hydrolase (scrB). Remarkably, sugars involved in levan biosynthesis are proposed to be transported through three distinct systems: a multiple-component ABC sugar transporter, a glucose/H⁺ symporter, and glucose- and fructose-specific phosphotransferase systems (PTS). Subsequently, recombinant HL25SacB levansucrase exhibited optimal activity at 40 °C and pH 5.0 in 50 mM sodium acetate buffer. The enzyme demonstrates high specificity in converting sucrose into a mixture of short-chain FOSs (DP 2–4) and levan, achieving a 62.5% conversion rate at 30 °C with 200 g/L sucrose over 24 h. These findings demonstrate the potential of this B. velezensis HL25 strain as an efficient whole-cell biocatalyst and highlight the applicability of the recombinant HL25SacB enzyme as a promising tool for sustainable production of FOSs and levan. Full article

Aluminum-ion batteries (AIBs) are emerging as promising alternatives to lithium-ion batteries due to their cost-effectiveness and resource abundance. However, their practical application is hindered by low capacity, poor cycle life, and limited rate capability. In this study, δ-MnO₂ and δ-MnO₂/Graphene composite cathodes are developed and tested in aqueous aluminum-ion batteries (AAIBs) using a mixture of 0.5 M Al₂(SO₄)₃ and 0.4 M MnSO₄ as the electrolyte. The electrochemical properties are evaluated alongside treated aluminum (TAl) and Zn–Al alloy anodes. Among the configurations tested, the δ-MnO₂/Graphene|0.5 M Al₂(SO₄)₃, 0.4 M MnSO₄|Zn–Al system showed the best performance, achieving a high discharge voltage of 1.63 V, a specific capacity of 746 mAh g⁻¹, and excellent cycling stability over 352 cycles. The stabilizing effect of graphene, due to increased oxygen vacancies and the formation of Mn–O–C bonds, enhances electron and ion transport, thereby improving cathode integrity and the overall performance of the AAIB. Additionally, the Zn–Al alloy anode extends the battery’s cycle life compared to the TAl anode. This work demonstrates the potential for low-cost, high-performance AAIBs, paving the way for more sustainable and scalable energy storage solutions. Full article

We present two case studies of tropospheric aerosol transport observed over the high-altitude Helmos observatory (1800–2300 m a.s.l.) in Greece during September 2021. Two cases were linked to Saharan dust intrusions, of which one was additionally linked to a mixture of biomass-burning and continental aerosols. Aerosol vertical profiles from the AIAS mobile backscatter/depolarization lidar (532 nm, NTUA) revealed distinct aerosol layers between 2 and 6 km a.s.l., with particle linear depolarization ratio values of up to 0.30–0.40, indicative of mineral dust. The elevated location of Helmos allows lidar measurements in the free troposphere, minimizing planetary boundary layer influence and improving the attribution of long-range transported aerosols. Radiative impacts were quantified using the LibRadtran model. For the 27 September dust outbreak, simulations showed strong shortwave absorption within 3–7 km, peaking at 5–6 km, with surface forcing reaching −25 W m⁻² and TOA forcing around −12 W m⁻², thus, implying a net cooling by 13 W m⁻² on the Earth’s atmosphere system. In contrast, the 30 September mixed aerosol case produced substantial solar attenuation, a surface heating rate of 2.57 K day⁻¹, and a small positive forcing aloft (~0.05 K day⁻¹). These results emphasize the contrasting radiative roles of dust and smoke over the Mediterranean and the importance of high-altitude observatories for constraining aerosol–radiation interactions. Full article

Enhancing fuel efficiency in public transportation requires the integration of complex multimodal data into interpretable, decision-relevant insights. However, traditional analytics and visualization methods often yield fragmented outputs that demand extensive human interpretation, limiting scalability and consistency. This study presents a multi-agent framework that leverages multimodal large language models (LLMs) to automate data narration and energy insight generation. The framework coordinates three specialized agents, including a data narration agent, an LLM-as-a-judge agent, and an optional human-in-the-loop evaluator, to iteratively transform analytical artifacts into coherent, stakeholder-oriented reports. The system is validated through a real-world case study on public bus transportation in Northern Jutland, Denmark, where fuel efficiency data from 4006 trips are analyzed using Gaussian Mixture Model clustering. Comparative experiments across five state-of-the-art LLMs and three prompting paradigms identify GPT-4.1 mini with Chain-of-Thought prompting as the optimal configuration, achieving 97.3% narrative accuracy while balancing interpretability and computational cost. The findings demonstrate that multi-agent orchestration significantly enhances factual precision, coherence, and scalability in LLM-based reporting. The proposed framework establishes a replicable and domain-adaptive methodology for AI-driven narrative generation and decision support in energy informatics. Full article

The geochemical characteristics of reinjection fluids play a crucial role in controlling water–rock interactions and the long-term stability of geothermal reservoirs. This study aims to evaluate how different fluid chemistries affect mineral dissolution–precipitation behavior and ion migration during geothermal reinjection. Five types of reinjection water—including geothermal source water (i.e., formation water from the reservoir), primary and secondary treated waters, and their mixtures—were reacted with carbonate rocks from the Wumishan Formation of the Xiong’an New Area, North China Basin, under reservoir-like conditions (70 °C, 17 MPa). A combination of batch experiments, inverse modeling using PHREEQC, and one-dimensional reactive transport simulations was employed. Results show that fluid pH, ionic strength, and saturation state significantly influence reaction pathways. Alkaline-treated waters enhanced silicate dissolution, increasing Na⁺, K⁺, and Si concentrations, while source water and its mixtures promoted carbonate precipitation, increasing the risk of clogging. Simulations revealed that the early injection stage is the most reactive, with rapid ion front advancement and strong mineral transformations. Reaction-controlled ions such as Ca²⁺ and SO₄²⁻ formed enrichment zones, while conservative ions like Na⁺ and Cl⁻ propagated more uniformly. Moderate alkaline regulation was found to mitigate carbonate scaling and improve silicate reactivity, thereby reducing permeability loss. This integrated approach provides mechanistic understanding and practical guidance for reinjection fluid design in medium-to-deep geothermal systems. Full article

The fields of healthcare and pharmaceutical science are increasingly focused on developing innovative and effective treatments. This trend is driven by a growing consumer demand for natural, sustainable, and highly functional polymer-based products. This study focuses on two biomaterials: chitosan and royal jelly. Chitosan, a linear polysaccharide derived from chitin, is well-regarded for its hemostatic and antimicrobial properties, making it an excellent candidate for wound healing applications. Royal jelly, a nutrient-rich secretion from honeybees, represents a complex mixture of proteins, lipids, vitamins, and antioxidants, notably 10-hydroxy-2-decenoic acid (10-H2DA). It is known for its anti-inflammatory, antioxidant, and regenerative effects on the skin. While the individual benefits of chitosan and royal jelly are well-documented, there is a significant research gap concerning their synergistic application in various treatments such as topical formulations, wound healing, regenerative medicine, and delivery transport processes. Ultimately, this review concludes that the synergistic effects of chitosan and royal jelly could provide a material platform with a superior dual-action profile, integrating the structural and antimicrobial benefits of chitosan with the powerful regenerative and anti-inflammatory effects of royal jelly. This synergy strongly supports their utility in developing next-generation, high-performance natural bioproducts for wound healing, bone regeneration, agriculture, or aquaculture applications. Full article

Microwave heating is a method with a uniform heating effect and environmental friendliness in in-place hot recycling, but the microwave absorption capacity of traditional asphalt mixtures is still insufficient. As an excellent microwave-absorbing material, magnetite powder has the characteristics of high temperature resistance, corrosion resistance, and good thermodynamic stability. This study selects it as the microwave-absorbing material, prepares AC (Asphalt Concrete) type and SMA (Stone Mastic Asphalt) type microwave asphalt mixtures by adjusting its content, and investigates its influence on the microwave-heating characteristics and pavement performance of the mixtures. Simulations of the microwave-heating process of AC-type mixtures using COMSOL software (COMSOL Multiphysics 6.2) show that magnetite powder achieves optimal performance in terms of heating effect and economic efficiency when its content is 0.5%. Subsequently, laboratory tests are conducted to study the wave absorption and temperature rise performance of AC and SMA microwave asphalt mixtures; combined with economic factors, the optimal contents of magnetite powder for the two types of mixtures are determined to be 0.5% and 1%, respectively, and at the same time, these results are explained based on multiple physical theories. Furthermore, pavement performance is investigated through laboratory tests, including high-temperature rutting tests, low-temperature bending tests, immersed Marshall tests, and freeze–thaw cycle durability tests, and the results indicate that the high-temperature performance, low-temperature performance, and water stability of the microwave asphalt mixtures all meet the specification requirements for pavement performance. Subsequently, after 15 freeze–thaw cycles, the splitting tensile strength retention rate and stiffness modulus of the two types of mixtures show minimal differences from those of ordinary mixtures, and there is no durability degradation caused by the incorporation of magnetite powder. Finally, outdoor environment verification is carried out, and the results show that under complex conditions such as environmental factors, the wave absorption and temperature rise rates of AC and SMA mixtures at optimal contents are 52.2% and 14.6% higher than those of ordinary AC and SMA asphalt mixtures, respectively. In addition, these microwave asphalt mixtures have the advantages of both sustainability and reduced carbon emissions. By combining simulation methods and experimental verification, this study finally prepared two types of microwave asphalt mixtures with excellent performance, not only improving the microwave absorption and heating performance of asphalt mixtures, but also reducing environmental pollution and energy consumption, which conforms to the development of green transportation. Full article

Per- and polyfluoroalkyl substances (PFASs) have attracted global attention due to their persistence and biological toxicity, becoming critical emerging contaminants in river and lake environments worldwide. Building upon existing studies, this work aims to comprehensively understand the pollution patterns, environmental behaviors, and potential risks of PFASs in freshwater systems, thereby providing scientific evidence and technical support for precise pollution control, risk prevention, and the protection of aquatic ecosystems and human health. Based on publications from 2002 to 2025 indexed in the Web of Science (WoS), bibliometric analysis was used to explore the temporal evolution and research hotspots of PFASs, and to systematically review their input pathways, pollution characteristics, environmental behaviors, influencing factors, and ecological and health risks in river and lake environments. Results show that PFAS inputs originate from both direct and indirect pathways. Direct emissions mainly stem from industrial production, consumer product use, and waste disposal, while indirect emissions arise from precursor transformation, secondary releases from wastewater treatment plants (WWTPs), and long-range atmospheric transport (LRAT). Affected by source distribution, physicochemical properties, and environmental conditions, PFASs display pronounced spatial variability among environmental media. Their partitioning, degradation, and migration are jointly controlled by molecular properties, aquatic physicochemical conditions, and interactions with dissolved organic matter (DOM). Current risk assessments indicate that PFASs generally pose low risks in non-industrial areas, yet elevated ecological and health risks persist in industrial clusters and regions with intensive aqueous film-forming foam (AFFF) use. Quantitative evaluation of mixture toxicity and chronic low-dose exposure risks remains insufficient and warrants further investigation. This study reveals the complex, dynamic environmental behaviors of PFASs in river and lake systems. Considering the interactions between PFASs and coexisting components, future research should emphasize mechanisms, key influencing factors, and synergistic control strategies under multi-media co-pollution. Developing quantitative risk assessment frameworks capable of characterizing integrated mixture toxicity will provide a scientific basis for the precise identification and effective management of PFAS pollution in aquatic environments. Full article

To investigate the influence of salt transport in water–steam mixtures on flow and heat transfer and to ensure the operational safety of steam injection boilers, this study simulated the behavior of high-dryness steam carrying salts in U-tubes. The analysis focused on three representative substances—silica, hematite, and calcium carbonate—to evaluate their effects on flow and heat transfer characteristics under varying conditions. The simulation results show that under specified operating conditions, vortices induced by rotational flow lead to complex flow behavior in U-tubes, with transitions from stratified flow to annular flow and back to stratified flow. The effects of salt precipitation on the temperature, velocity, and pressure fields of the boiling flow were also examined. The findings indicate that for pure water, large gradients and multiple vortices adversely affect flow stability, whereas the introduction of small amounts of salts provides localized stabilization in regions of the fluid away from the wall. Full article

The demand for reliable Environmental Product Declarations (EPDs) of asphalt mixtures is growing, particularly as they are increasingly used in public road construction tenders across Europe. However, the reliability and comparability of EPDs remain limited due to two main challenges: (i) significant variability in dataset selection for key materials such as bitumen and aggregates, and (ii) uncertainty regarding the influence of operational factors, including aggregate moisture, mixing temperature, and transportation. The objective of this research is to assess the influence of dataset selection and operational parameters on the environmental performance of an asphalt mixture, focusing on improving the reliability of EPDs. Within this research, a Life Cycle Assessment (LCA) was conducted using a cradle-to-gate approach (A1–A3), including modules C1–C4 and D, in compliance with EN 15804:2019+A2:2020. Primary data were collected from an asphalt plant in Lithuania, while secondary data were obtained from the Ecoinvent database. The sensitivity analyses were performed to investigate the variation of data set choices and key operational factors that influence the environmental impact. The assessment was carried out using the Simapro 9.6 software and the EF 3.1 impact assessment method. The results indicate significant sensitivity to dataset selection, particularly for bitumen and dolomite production, leading to environmental impact variations of up to 41.8% and 35.3%, respectively. Among operational factors, reducing aggregate moisture from 5% to 3% by sheltering stockpiles helps achieve the highest environmental impact reduction (3.2% under the Aggregate Single Score), while lowering mixing temperatures to 130 °C resulted in a 1.6% decrease. Transportation mode selection contributed to emission variations between 1.8% and 6.7%, with long-distance aggregate transport increasing emissions by up to 14.6%. The research findings underscore the critical need for harmonizing dataset selection and optimizing operational processes to improve asphalt sustainability. Standardizing datasets is essential for ensuring fair and transparent EPD generation for asphalt mixtures, particularly when used in road construction tenders, as seen in several European countries. Future research should explore the integration of reclaimed asphalt (RA) and assess its potential environmental benefits. Full article

The appropriate selection of renovation plaster properties is essential for ensuring the durability and effectiveness of conservation works. This study focused on the design and characterization of cement-based renovation mortars modified with synthetic zeolites with different Si/Al ratios. It was assumed that high-silica zeolites would provide more favorable mechanical and hygric performance than low-silica types. Owing to their porous structure and pozzolanic reactivity, zeolites proved to be effective additives, enhancing both the microstructure and functionality of the mortars. The modified mixtures exhibited increased total porosity, higher capillary absorption, and improved moisture transport compared with the reference mortar based on CEM I 52.5R. Dynamic vapor sorption tests confirmed that the zeolite-containing mortars achieved Moisture Buffer Values (MBV) above 2.0 g/m², which corresponds to the “excellent” moisture buffering class. Electrical resistivity measurements further demonstrated the relationship between denser microstructure and enhanced durability. At the frequency of 10 kHz, the electrical resistivity of the reference mortar reached 43,858 Ω·m, while mortars with 15% ZSM-5 and 15% Na-A achieved 62,110 Ω·m and 21,737 Ω·m. These results show that the addition of high-silica zeolite promotes the formation of a denser and more insulating matrix, highlighting the potential of this method for non-destructive quality assessment. The best overall performance was observed in mortars containing the high-silica zeolite ZSM-5. A 35% replacement of cement with ZSM-5 increased compressive strength by 10.5% compared with the reference mortar R (4.3 MPa). Frost resistance tests showed minimal mass loss (0.03% at 15% and 1.79% at 35% replacement), and ZSM-5 mortars also maintained integrity under salt crystallization. These improvements were attributed to the reaction of reactive SiO₂ and Al₂O₃ from the zeolites with Ca(OH)₂, leading to the formation of additional C-S-H. A higher Si/Al ratio promoted a denser, fibrous C-S-H morphology, as confirmed by SEM, which explains the improved strength and durability of mortars modified with ZSM-5. Full article