Search Results (101)

This study investigates the organic chemical content and ecological impact of firefighting runoff collected from real-world fire scenarios. To establish a direct link between chemical composition and environmental hazard, a comprehensive analytical framework was employed, integrating molecular fingerprinting via gas chromatography–tandem mass spectrometry (GC-MS/MS) with a multi-trophic battery of bioassays, including Aliivibrio fischeri, Heterocypris incongruens, and Sinapis alba L. The chemical characterization revealed highly heterogeneous profiles dominated by esters (up to 41%), alcohols (up to 25%), and phenols (up to 22%). A unique molecular marker, nitriles (15.9%), was identified in tire-related fire effluents, which corresponded with potent metabolic suppression in the Toxi-ChromoTest™. Ecotoxicological results demonstrated that most effluents reached Class IV (high acute toxicity), with universal 100% lethality observed in samples from large-scale incidents. Furthermore, a significant stimulatory effect was detected in S. alba (growth stimulation up to 12%) for scenarios involving polyurethane foam, illustrating the selective toxicity of specific molecular groups. Beyond ecological degradation, the high phenolic and nitrile loads identified across multiple scenarios represent a substantial public health risk, as these persistent contaminants can infiltrate groundwater, bypass conventional water treatment, and bioaccumulate in the human food chain. The findings suggest that the synergistic effect of hydrophobic xenobiotics and firefighting foams poses a severe threat to both aquatic biodiversity and human chemical safety. This research emphasizes that linking molecular fingerprinting with multi-level bioindicators is essential for a holistic risk assessment of firefighting operations. Full article

Geopolymer concretes are increasingly regarded as advanced construction materials for applications requiring high thermal and chemical resistance. This article is a continuation of previously published research and focuses on the mechanical behaviour of geopolymer concretes containing aggregates made of foamed geopolymers and lightweight mineral aggregates, such as expanded clay and perlite, intended for use in chimney flue components. The aim of the study was to determine the influence of lightweight aggregates on the relationship between thermal insulation and the strength parameters of geopolymer concretes intended for use at elevated temperatures. Foamed geopolymer aggregates were produced by a controlled chemical foaming process, followed by grinding to specific grain sizes, yielding highly porous aggregates with low thermal conductivity, reaching approximately 0.075–0.099 W/(m·K). These aggregates were used as lightweight fillers in geopolymer concretes based on class F fly ash activated with alkaline solutions. The resulting composites were designed to combine low density and high thermal insulation with adequate mechanical strength. The mechanical properties of the developed concretes were assessed on the basis of compressive strength tests on cubic specimens and tensile strength in beam bending tests, carried out in accordance with standards. The results presented confirm that the use of foamed geopolymer aggregates enables a simultaneous increase in thermal insulation and the design of ultra-lightweight structural elements with sufficient load-bearing capacity for chimney systems (including suspended ones). This combination of low thermal conductivity, reduced mass, and appropriate mechanical properties makes geopolymer concretes with lightweight mineral and geopolymer aggregates a promising alternative to traditional ceramic materials. Full article

It is shown that transient trapped surfaces form in a class of emerging globally hyperbolic spacetimes, within punctured Planck-scale neighbourhoods of the geon supported on intersecting singular supports whose intersection forms a characteristic core in a non-strongly causal setting. These neighbourhoods shrink towards the intersecting singular support in the distributional geometry. In particular, the trapped surfaces occur near the characteristic limit corresponding to the unstable equilibrium of the self-gravitating geon. They act as an effective classical barrier for descriptions formulated purely within smooth differential geometry. The area of these trapped-surface configurations, computed on Planck-referenced neighbourhoods, is shown to tend to zero both in the asymptotically flat limit of the emerging spacetime and in the geon limit. Thus, transient trapped surfaces evaporate in the sense that their area vanishes as classical and asymptotically flat spacetime emerges within the quantum foam framework. A state-counting generating function for the transient trapped surfaces is constructed from the coherent-state density operator. This generating function maps microscopic occupation-number sectors to macroscopic data and thereby allows a definition of Boltzmann entropy (not to be confused with the von Neumann entropy, which is zero for any pure coherent state). Since the coherent state is constructed to implement the correspondence principle, expectation values of the relevant quantised observables reproduce their classical values. In particular, the expectation value of the bosonic occupation-number operator serves as a microstate-counting variable in the coherent sector. The generating function takes the form of an exponential of this expectation value, leading to an entropy–area relation consistent with the Hawking–Bekenstein scaling. Full article

Glycyrrhizic acid and its derivatives are a crucial class of glycoside terpenoids with significant pharmaceutical and food industry applications. The biotransformation of glycyrrhizin (GL) into glycyrrhetic acid 3-O-mono-β-D-glucuronide (GAMG) and glycyrrhetinic acid (GA) can enhance the production of these valuable compounds. This study aimed to develop strategies to improve the catalytic and operational stability of β-glucuronidase from wild-type Talaromyces pinophilus Li-93, previously known as Penicillium purpurogenum Li-3 (w-PGUS), for efficient GL hydrolysis. Whole cells of T. pinophilus Li-93 expressing w-PGUS were capable of directly converting GL into GAMG. To enhance enzyme stability and reusability, three polymeric supports including, polyurethane foam (PUF), loofah sponge (LS), and polyvinyl chloride (PVC), were evaluated for immobilization of w-PGUS from the fermentation medium. Among these, PUF was the most effective immobilization support, yielding higher immobilization efficiency, GAMG production, and biomass retention. Under optimized conditions (1% PUF, 1.5 g.L⁻¹ w-PGUS inoculum, pH 5.0, 36 °C, 180 rpm), the immobilized w-PGUS produced a final GAMG yield of 3.90 g.L⁻¹, achieving 67.10% immobilization efficiency within 72 h. The PUF-immobilized w-PGUS retained 37.51% of its initial activity after 10 repeated batch reactions, whereas free w-PGUS retained only 6.21%. Additionally, the storage stability of immobilized w-PGUS was significantly higher (40.22%) than that of free w-PGUS (14.74%) after 30 days. Immobilization slightly reduced the initial yield due to mass-transfer limits but enabled much higher cumulative GAMG production through improved stability and reusability. Full article

The present study evaluates the electrochemical behaviour of reinforcing steel embedded in an alkali-activated eco-cellular geopolymer concrete designed for applications in environments with high chloride exposure. The material was formulated using a ternary precursor composed of fluid catalytic cracking residue (FCC), Class F fly ash, and ground granulated blast furnace slag (BFS), activated with an alkaline solution and combined with preformed foam to generate a microstructure characterised by predominantly closed porosity and low capillary connectivity. The electrochemical response of the system was assessed through open circuit potential (OCP) measurements, Tafel polarisation curves, electrochemical impedance spectroscopy (EIS), and potentiodynamic tests under accelerated exposure to NaCl solutions. The results demonstrate a markedly improved electrochemical performance, evidenced by shifts in OCP towards more noble values, reductions of 45–65% in corrosion current density (Icorr), and increases of up to fourfold in charge transfer resistance (Rct), together with the development of broader and more stable passive regions. This behaviour is attributed to the synergistic interaction between the formation of dense N-(C)-A-S-H (sodium/calcium–aluminosilicate hydrate) and C-(A)-S-H (calcium–aluminosilicate hydrate) gels, the eco-cellular architecture with low capillary connectivity, and the stable high alkalinity of the activated matrix, which collectively restrict ionic transport and promote the passive stability of the reinforcing steel—defined here by noble OCP values, low Icorr, high Rct, and sustained passive domains in polarisation curves. Overall, the findings position the developed eco-cellular geopolymer concrete as a sustainable, high-performance alternative for infrastructure exposed to chloride-rich environments. Full article

Shape-memory polymers (SMPs) are a class of smart materials capable of recovering their original shape from a programmed temporary shape in response to external stimuli such as heat, light, or magnetic fields. SMPs have attracted significant interest for biomedical devices and soft robotics due to their large recoverable strains, programmable mechanical and thermal properties, tunable activation temperatures, responsiveness to various stimuli, low density, and ease of processing via additive manufacturing techniques, as well as demonstrated biocompatibility and potential bioresorbability. This review summarises recent progress in the fundamentals, classification, activation mechanisms, and fabrication strategies of SMPs, focusing particularly on design principles that influence performance relevant to specific applications. Both thermally and non-thermally activated SMP systems are discussed, alongside methods for controlling activation temperatures, including plasticisation, copolymerisation, and modulation of cross-linking density. The use of functional nanofillers to enhance thermal and electrical conductivity, mechanical strength, and actuation efficiency is also considered. Current manufacturing techniques are critically evaluated in terms of resolution, material compatibility, scalability, and integration potential. Biodegradable SMPs are highlighted, with discussion of degradation behaviour, biocompatibility, and demonstrations in devices such as haemostatic foams, embolic implants, and bone scaffolds. However, despite their promising potential, the widespread application of SMPs faces several challenges, including non-uniform activation, the need to balance mechanical strength with shape recovery, and limited standardisation. Addressing these issues is critical for advancing SMPs from laboratory research to clinical and industrial applications. Full article

Residential space heating in Northern Europe requires long-duration thermal storage to align summer solar gains with winter heating demand. This study investigates a compact sand-based seasonal thermal energy storage integrated with flat-plate solar collectors for an A+ class single-family house in Kaunas, Lithuania. An iterative co-design couples collector sizing with the seasonal charging target and a 3D COMSOL Multiphysics model of a 300 m³ sand-filled, phenolic foam-insulated system, with a 1D conjugate model of a copper pipe heat-exchanger network. The system was charged from March to September and discharged from October to February under measured-weather boundary conditions across three consecutive annual cycles. During the first year, the storage supplied the entire winter heating demand, though 35.2% of the input energy was lost through conduction, resulting in an end-of-cycle average sand temperature slightly below the initial state. In subsequent years, both the peak sand temperature and the residual end-of-cycle temperature increased by 3.7 °C and 3.2 °C, respectively, by the third year, indicating cumulative thermal recovery and improved retention. Meanwhile, the peak conductive losses rate decreased by 98 W, and cumulative annual losses decreased by 781.4 kWh in the third year, with an average annual reduction of 4.15%. These results highlight the progressive self-conditioning of the surrounding soil and demonstrate that a low-cost, sand-based storage system can sustain a complete seasonal heating supply with declining losses, offering a robust and scalable approach for residential building heating applications. Full article

The “Double High—Double Extra High” stage of offshore oilfields, where large pumps lift liquids, leads to a rapid rise in water concentration, which triggers a decrease in rock strength and exacerbates the risk of sand production; this leads to a blockage of the reservoir, thus restricting the release of production capacity. In this paper, for the typical weak cementation strength of unconsolidated sandstone of a Class I reservoir in the P oilfield, numerical simulation and indoor experimental methods are utilized to explore the plugging mechanism and law of the water-contenting conditions, with micro-sand and mud conditions, on the screen. Considering the combined effects of reservoir particulate transport plugging and near-well sand control media plugging, the additional pressure drop and skin factor calculation model is constructed, and a dynamic capacity prediction model for sand control wells is formed. By matching the physical properties of the target reservoir and optimizing the sand control method, the production capacity prediction model and the sand control optimization design method for the high water-content period of the unconsolidated sandstone reservoir are finally obtained. The results show that the median sand size of well A1 in the P oilfield Class I reservoir is 220 μm, the sand transportation diameter is about 15–20 m, the serious plugging area near the well is distributed in 2–2.5 m, and the predicted loss of production capacity is about 18%. The use of a foam metal screen can significantly reduce the plugging pressure and increase the flow of crude oil, which is 2.2 and 1.2 times higher than that of the precision mesh and pre-filled screen, respectively. These research results can provide technical support and theoretical guidance for the sustained, efficient, and stable production of sand reservoirs in the Bohai Oilfield. Full article

The incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) play central roles in metabolic and cardiovascular regulation. GLP-1 receptor agonists (GLP-1RAs) are established therapies for type 2 diabetes mellitus (T2DM) and obesity because of their insulinotropic effects, weight reduction, and proven cardiovascular benefit in trial level. In contrast, GIP was historically overlooked due to reduced β-cell responsiveness in T2DM. The development of dual GIP/GLP-1 receptor agonists has reshaped this view. Tirzepatide, the first-in-class co-agonist, an antidiabetic medication to treat type 2 diabetes and for weight loss, provides superior glycemic control and weight loss compared with selective GLP-1RAs in clinical trials, demonstrating synergistic actions between the two incretin pathways. This review summarizes key physiology, pathophysiology, and therapeutic evidence in incretin biology. We describe secretion patterns, receptor distributions, and distinct actions of GIP and GLP-1, as well as alterations in incretin signaling in T2DM and obesity. Cardiovascular protective mechanisms are outlined, including improvements in lipid metabolism, reductions in blood pressure, enhanced endothelial nitric oxide activity, suppression of macrophage inflammation, decreased foam-cell formation, and stabilization of atherosclerotic plaques. At the therapeutic level, emerging directions—such as dual and triple agonists—and unresolved questions regarding long-term vascular effects of GIP and the potential for genotype-guided incretin therapy are also discussed. Collectively, these findings highlight an emerging shift toward integrated incretin-axis modulation as a therapeutic strategy for metabolic and cardiovascular disease. Full article

The development of novel materials from biomass is a potential alternative to replace traditional petrochemical resources. In accordance with the “Bamboo Substitute Plastic” initiative, bamboo-based lightweight porous materials are a class of foam materials fully prepared from biomass resources with a lightweight and high-strength structure. However, issues such as excessive lignin content and uneven pore structure distribution within these materials hinder their application. This study utilized bamboo powder as a raw material to prepare lightweight, porous molding materials through a hydrothermal grinding process. The influence of different concentrations of alkaline pretreatment was investigated. The fabricated molding material had a density of 0.36–0.49 g/cm³ at 80 °C and 0.32–0.38 g/cm³ at 105 °C. Samples dried at 80 °C had a water absorption of 161% to 304%, while those dried at 105 °C had a water absorption of 223% to 305%. The wet swelling was characterized by volume expansion from 6.2% to 7.7%. The surface of the molding materials became increasingly homogeneous without any cracks due to the alkali pretreatment. FTIR data showed that more surface hydroxyl groups were observed after alkaline pretreatment, and some carbonyl groups in the hemicellulose structure were removed; meanwhile, the crystallinity index after alkaline pretreatment was higher than that of untreated bamboo. The alkali solution was proposed to remove part of the lignin and improve the fibrillation degree of the bamboo fibers. The highest tensile strength of the samples was 9.63 MPa, while the highest compressive strength obtained was 0.92 MPa under the alkali treatment. With lightweight and fully degradable properties, the bamboo-based porous molding materials have promising application prospects in environmental protection, construction, packaging, and related fields. Full article

The ubiquitous presence of microplastics across environmental compartments presents a formidable ecotoxicological and risk assessment challenge, fundamentally complicated by the link between microplastic morphology and differential toxicological outcomes. Current analytical methods face a significant measurement bottleneck, hindering the precise, high-throughput characterization needed for robust mechanistic and exposure studies. To address this, we introduce MNv4-Conv-M-fpn, a novel deep learning model specifically engineered for multi-class microplastic segmentation and morphological characterization from microscopic images. This model is designed to provide the toxicologically-relevant granularity required for rigorous risk assessment, segmenting images into six classes: five distinct microplastic categories (fiber, fragment, sphere, foam, and film) and the background. By incorporating advanced architectural features—including transfer learning, a Feature Pyramid Network, and a Feature Fusion Module—our approach achieves high accuracy, computational efficiency, and near real-time inference speed. Comprehensive validation using a diverse dataset demonstrates that MNv4-Conv-M-fpn outperforms existing segmentation methods while maintaining low computational load. This makes the model well-suited for high-throughput deployment in environmental laboratories and resource-constrained monitoring efforts. This approach offers a valuable tool for environmental monitoring, enabling more precise and scalable analysis of microplastic pollution in various ecosystems. Full article

Due to environmental disasters caused by the use of plastic packaging, particularly expanded polystyrene (EPS), there is an urgent need to identify sustainable alternatives. Biodegradable foams derived from renewable polysaccharides have emerged as highly promising candidates to replace EPS, given their comparable cushioning and barrier properties. However, despite the rapid growth of research in this area, there has not yet been a comprehensive review addressing biodegradable foams as a specific class of packaging materials, particularly regarding their processing routes, raw materials, and functionalization. This work discusses conventional techniques for producing biodegradable foams, such as thermoforming and extrusion, as well as innovative methods, including supercritical fluids and 3D printing. It also examines key renewable polysaccharides and the incorporation of agro-industrial residues into foam matrices, aiming to improve performance and reduce costs. Furthermore, the article highlights advances in composite and nanocomposite foams, with particular emphasis on active properties such as ethylene absorption and antimicrobial activity capable of extending food shelf life. By directing attention to biodegradable foams as substitutes for expanded polystyrene, this review provides a unique contribution, filling a critical gap in the field and offering a foundation for future studies aimed at developing scalable, low-cost, and eco-friendly alternatives to plastics. Full article

Fluorine-free foams (FFFs) have been introduced as alternatives to aqueous film-forming foams (AFFFs), which are based on per- and polyfluoroalkyl substances (PFASs). However, adoption of FFFs remains limited due to the lack of universal drop-in replacements and limited data on their health and environmental impacts. This study examined incentives and barriers to implementing FFFs in Fire Training Facilities (FTFs) to support the transition away from PFAS-based products. A survey was conducted from September 2022 to December 2023 across the U.S. and Canadian FTFs, including state-funded facilities, metropolitan fire departments, airports, military, and industrial brigades. Developed in partnership with fire service organizations, the survey assessed current foam use, motivations for transition, and associated challenges. Of all FTF training with Class B foams, 38% reported using FFF products. Primary incentives included environmental and health concerns, safety, and regulatory pressures. Key challenges were transition costs, training requirements, and uncertainties around disposal of foams. These findings highlight that while momentum toward FFF adoption is evident, ensuring products are genuinely PFAS-free and providing comprehensive training will be critical for effective, large-scale implementation. Fire training facilities can play a pivotal role in guiding this transition. Full article

Polyurethane foams containing heterocyclic rings are characterized by high thermal resistance, but unfortunately, they are flammable. This work examined the effect of halogen-free flame retardants such as melamine and expanded graphite: EG 096 and EG 290 on the properties of foams with a 1,3-pyrimidine ring. Oligoetherol obtained from 6-aminouracil, ethylene carbonate, and propylene oxide was foamed with polymeric diphenylmethane 4,4′-diisocyanate with the addition of flame retardants. The oxygen index was determined, and flammability tests were conducted on the resulting foams. Their apparent density, water absorption, thermal resistance, thermal conductivity coefficient, and compressive strength were also examined. Both melamine and expanded graphite significantly reduce the flammability of foams. The resulting foams are classified as V-0 flammability class, and their oxygen index is in the range of 24.9–29.5 vol.%. Expanded graphite is a better flame retardant and does not cause deterioration of other foam properties. Full article

This review covers the current state, challenges, and future directions of catalytic combustion technologies for mitigating fugitive methane emissions from the fossil fuel industry. Methane, a potent greenhouse gas, is released from diverse sources, including natural gas production, oil operations, coal mining, and natural gas engines. The paper details the primary emission sources, and addresses the technical difficulties associated with dilute and variable methane streams such as ventilation air methane (VAM) from underground coal mines and low-concentration leaks from oil and gas infrastructure. Catalytic combustion is a useful abatement solution due to its ability to destruct methane in lean and challenging conditions at lower temperatures than conventional combustion, thereby minimizing secondary pollutant formation such as NO_X. The review surveys the key catalyst classes, including precious metals, transition metal oxides, hexa-aluminates, and perovskites, and underscores the crucial role of reactor internals, comparing packed beds, monoliths, and open-cell foams in terms of activity, mass transfer, and pressure drop. The paper discusses advanced reactor designs, including flow-reversal and other recuperative systems, modelling approaches, and the promise of advanced manufacturing for next-generation catalytic devices. The review highlights the research needs for catalyst durability, reactor integration, and real-world deployment to enable reliable methane abatement. Full article