Search Results (93)

Carbon fiber (CF) and carbon fiber-reinforced polymers (CFRPs) are widely used in the aerospace, automotive, and energy sectors due to their high strength, stiffness, and low density. However, significant waste is generated during manufacturing and after the use of CFRPs. Traditional disposal methods like landfilling and incineration are unsustainable. CFRP machining processes, such as drilling and milling, produce fine chips and dust that are difficult to recycle due to their heterogeneity and contamination. This study investigates the oxidation behavior of CFRP drilling waste from two types of materials (tube and plate) under oxidative (non-inert) conditions. Thermogravimetric analysis (TGA) was performed from 200 °C to 800 °C to assess weight loss related to polymer degradation and carbon fiber integrity. Scanning electron microscopy (SEM) was used to analyze morphological changes and fiber damage. The optimal range for removing the polymer matrix without significant fiber degradation has been identified as 500–600 °C. At temperatures above 700 °C, notable surface and internal fiber damage occurred, along with nanostructure formation, which may pose health and environmental risks. The results show that partial fiber recovery is possible under ambient conditions, and this must be considered regarding the harmful risks to the human body if submicron particles are inhaled. This research supports sustainable CFRP recycling and fire hazard mitigation. Full article

This study evaluates the replacement of petroleum-based naphthenic oil with four types of soybean-derived alternatives—virgin soybean oil (SBO), epoxidized SBO (ESBO), expired SBO, and recycled SBO—in styrene–butadiene rubber (SBR) composites. The materials were tested in both staining rubber (SR) and non-staining rubber (NSR) systems to assess processing characteristics, mechanical performance, and environmental durability. Among the alternatives, SBO demonstrated the best overall performance, improving processability and tensile strength by over 10%, while ESBO enhanced ozone resistance by 35% due to its epoxide functionality. Expired and recycled SBOs maintained essential mechanical properties within 90% of virgin SBO values. The full replacement of CH450 with SBO in tire prototypes resulted in burst strength exceeding 1000 kPa and stable appearance after 5000 km of road testing. To validate industrial relevance, the developed green tire was exhibited at the 2025 Taipei International Cycle Show, attracting interest from international buyers and stakeholders for its eco-friendly composition and carbon footprint reduction potential, thereby demonstrating both technical feasibility and commercial viability. Full article

Using the enzyme-induced carbonate precipitation (EICP) technique to solidify rubber and clay mixtures as lightweight backfill is a feasible way to reduce waste tire impacts and boost rubber recycling in geotech engineering. In this study, a comprehensive laboratory investigation, including triaxial compression, oedometer, permeability, and nuclear magnetic resonance (NMR) tests, was conducted on EICP-reinforced rubber particle solidified clay (hereafter referred to as EICP-RC solidified clay) to evaluate the effects of rubber particle content and size on the mechanical behavior of the improved soil under various solidification conditions and to elucidate the solidification mechanism. The results show that although rubber particles inhibit EICP, they significantly enhance the mechanical properties of the samples. The addition of 5% rubber particles (rubber A) increased cohesion by 11% and the internal friction angle by 18% compared to EICP-treated clay without rubber. Additionally, incorporating smaller-sized tire particles facilitated pore filling, resulting in lower compression and swelling indices and reduced permeability coefficients, making these materials suitable for use behind retaining walls and in embankment construction. Full article

Recycling washed mineral waste, generated as a byproduct of the mechanical wastewater treatment process, can be a beneficial alternative to widely used natural sand in construction. Studies on material from the Warsaw agglomeration, available in quantities sufficient for construction applications, demonstrated its high usability in specific hydrotechnical applications. Key laboratory tests for material characterization included physical, permeability, mechanical, and chemical property analyses. The tested waste corresponds to uniformly graded medium sands (uniformity coefficient: 2.20) and weakly calcareous (calcium carbonate content: 2.25–3.29%) mineral soils with organic content ranging from 0.24% to 1.49%. The minimum heavy metal immobilization level reached 91.45%. At maximum dry density of the soil skeleton (1.78/1.79 g/cm³) and optimal moisture content (11.34/11.95%), the hydraulic conductivity reached 4.38/7.71 m/d. The mechanical parameters of washed mineral waste included internal friction angle (34.4/37.8°) and apparent cohesion (9.37/14.98 kPa). The values of the determined parameters are comparable to those of natural sands used as construction aggregates. As a result, washed mineral waste has a high potential for use as an alternative material to natural sand in the analyzed hydrotechnical applications, particularly for flood embankment construction, by applicable technical standards and construction guidelines. Full article

The development of efficient and sustainable water recycling systems is essential for long-term human missions and the establishment of space habitats on the Moon, Mars, and beyond. Humidity condensate (HC) is a low-strength wastewater that is currently recycled on the International Space Station (ISS). The main contaminants in HC are primarily low-molecular-weight organics and ammonia. This has caused operational issues due to microbial growth in the Water Process Assembly (WPA) storage tank as well as failure of downstream systems. In addition, treatment of this wastewater primarily uses adsorptive and exchange media, which must be continually resupplied and represent a significant life-cycle cost. This study demonstrates the integration of a membrane-aerated biological reactor (MABR) for pretreatment and storage of HC, followed by brackish water reverse osmosis (BWRO). Two system configurations were tested: (1) periodic MABR fluid was sent to batch RO operating at 90% water recovery with the RO concentrate sent to a separate waste tank; and (2) periodic MABR fluid was sent to batch RO operating at 90% recovery with the RO concentrate returned to the MABR (accumulating salinity in the MABR). With an external recycle tank (configuration 2), the system produced 2160 L (i.e., 1080 crew-days) of near potable water (dissolved organic carbon (DOC) < 10 mg/L, total nitrogen (TN) < 12 mg/L, total dissolved solids (TDS) < 30 mg/L) with a single membrane (weight of 260 g). When the MABR was used as the RO recycle tank (configuration 1), 1100 L of permeate could be produced on a single membrane; RO permeate quality was slightly better but generally similar to the first configuration even though no brine was wasted during the run. The results suggest that this hybrid system has the potential to significantly enhance the self-sufficiency of space habitats, supporting sustainable extraterrestrial human habitation, as well as reducing current operational problems on the ISS. These systems may also apply to extreme locations such as remote/isolated terrestrial locations, especially in arid and semi-arid regions. Full article

The quest to establish permanent outposts in space, the Moon, and Mars requires growing plants for nutrition, water purification, and carbon/nutrient recycling, as well as the psychological well-being of crews and personnel on extra-terrestrial platforms/outposts. To achieve these essential goals, the safety, quality, and sustainability of plant material grown in space should be comparable to Earth-grown crops. In this study, radish plants were grown at 2500 ppm CO₂ in two successive grow-outs on the International Space Station and at similar CO₂ partial pressure at the Kennedy Space Center. An additional control experiment was performed at the University of Louisiana Lafayette laboratory, at ambient CO₂. Subsequent analyses of glucosinolate and sugar species and content showed that regardless of growth condition, glucoraphasatin, glucoraphenin, glucoerucin, glucobrassicin, 4-hydroxyglucobrassicin, 4-methoxyglucobrassicin, and three aliphatic GSLs tentatively assigned to 3-methylpentyl GSL, 4-methylpentyl GSL, and n-hexyl GSL were present in all examined plants. The most common sugars were fructose, glucose, and sucrose, but some plants also contained galactose, maltose, rhamnose, and trehalose. The variability of individual secondary metabolite abundances was not related to gravity conditions but appeared more sensitive to CO₂ concentration. No indication was found that radish cultivation in space resulted in stress(es) that increased glucosinolate secondary metabolism. Flavor and nutrient components in space-grown plants were comparable to cultivation on Earth. Full article

This study provides a bibliometric analysis of life cycle assessments (LCAs) to explore the sustainability potential of mass timber buildings, focusing on glulam. The analysis highlights regional differences in carbon footprint performance within the ISO 14040 and EN 15978 frameworks. LCA results from representative countries across six continents show that wood buildings, compared to traditional materials, have a reduced carbon footprint. The geographical distribution of forest resources significantly influences the carbon footprint of glulam production. Europe and North America demonstrate optimal performance metrics (e.g., carbon sequestration), attributable to advanced technology and investment in long-term sustainable forest management. Our review research shows the lowest glulam carbon footprints (28–70% lower than traditional materials) due to clean energy and sustainable practices. In contrast, Asia and Africa exhibit systemic deficits, driven by resource scarcity, climatic stressors, and land-use pressures. South America and Oceania display transitional dynamics, with heterogeneous outcomes influenced by localized deforestation trends and conservation efficacy. Glulam buildings outperformed concrete and steel across 11–18 environmental categories, with carbon storage offsetting 30–47% of emissions and energy mixes cutting operational impacts by up to 67%. Circular strategies like recycling and prefabrication reduced end-of-life emissions by 12–29% and cut construction time and costs. Social benefits included job creation (e.g., 1 million in the EU) and improved well-being in wooden interiors. To further reduce carbon footprint disparities, this study emphasizes sustainable forest management, longer building lifespans, optimized energy mixes, shorter transport distances, advanced production technologies, and improved recycling systems. Additionally, the circular economy and social benefits of glulam buildings, such as reduced construction costs, value recovery, and job creation, are highlighted. In the future, prioritizing equitable partnerships and enhancing international exchanges of technical expertise will facilitate the adoption of sustainable practices in glulam buildings and advance decarbonization goals in the global building sector. Full article

In the context of carbon trading policy, carbon emissions in the supply chain of new energy vehicles have received much attention in academic research and practice. Consumer preference for environmental friendliness is also growing in new energy vehicle supply chain operations, which has prompted new energy vehicle manufacturers to invest in carbon abatement technologies to improve the environmental friendliness of new energy vehicles. At the same time, the increased demand for new energy vehicles will also increase the green promotion of third-party power battery recycling companies to facilitate the recycling of power batteries. Considering these special features in the new energy vehicle supply chain, we applied a differential game model to examine the carbon emission reduction behaviors and green promotion technologies of the new energy vehicle supply chain members from a long-term and dynamic perspective. Supply chain equilibrium strategies under four different scenarios were analyzed and compared, numerical experiments were conducted to validate the theoretical results, and sensitivity analyses were performed to identify further insights. The results of the study show that a unit carbon trading price reaching a critical threshold is a prerequisite for technical cooperation between the new energy vehicle manufacturer and the third-party power battery recycling company. It provides a theoretical basis for the government to set the carbon price, and it effectively stimulates the cooperation and emission reduction drive of new energy vehicle companies. The study breaks through the traditional cost–benefit framework, internalizes the carbon price as a supply chain cooperation drive, and opens up a new paradigm for new energy vehicle industry research. Full article

High-performance discontinuous carbon-fiber-reinforced thermoplastics (CFRTPs) offer promising manufacturing flexibility and recyclability for advanced composite applications. However, their mechanical performance and reliability strongly depend on the internal fiber architecture, which is largely determined by the molding process. In this study, three distinct compression molding approaches—CFRTP sheet molding compounds (SMCs), bulk molding compounds (BMCs), and free-edge molding compounds (FMCs)—were systematically evaluated to investigate how processing parameters affect fiber orientation, tape deformation, and impregnation quality. X-ray micro-computed tomography (XCT) was employed to visualize and quantify the internal structures of each material, focusing on the visualization and quantification of in-plane and out-of-plane fiber alignment and other internal structure features. The results indicate that CFRTP-SMC retains largely intact tape layers and achieves better impregnation, leading to more uniform and predictable internal geometry. Although CFRTP-BMC exhibits greater tape deformation and splitting due to increased flow, its simpler molding process and better tolerance for tape shape distortion suggest potential advantages for recycled applications. In contrast, CFRTP-FMC shows significant tape fragmentation and poor impregnation, particularly near free edges. These findings underscore the critical role of a controlled molding process in achieving a consistent internal structure for these materials for the first time. This study highlights the utility of advanced XCT methods for optimizing process design and advancing the use of high-performance discontinuous CFRTP in industry. Full article

There is an increasing demand to replace traditional construction techniques with more sustainable systems that can reduce environmental impacts. Emissions are typically assessed only in carbon dioxide and embodied energy terms, yet these metrics alone cannot fully capture the overall impact generated. This study provides a comparative Life Cycle Assessment (LCA) of three steel warehouse projects with varying cladding systems: steel walls (SW), steel-clay brick walls (SClaW), and steel-concrete block walls (SConW). Life Cycle Assessment (LCA) methodology was used to assess the environmental impact of materials used during the whole life cycle. The study used the software program SimaPro (System for Integrated Environmental Assessment of Products) version 9.6.0.1, with data extracted from the international Ecoinvent database. ReCiPe Midpoint approach were adopted to assess potential impacts. The results indicate that the SW project under end-of-life Scenario 2—waste recycling—exhibited the lowest impacts across most categories, followed by the SConW and SClaW projects. The findings emphasize the environmental benefits of utilizing steel cladding systems over brick or concrete masonry and considering recycling as the end of life of the materials. Additionally, the study provides insights into the significance of material choices in minimizing environmental impact on human health, resource availability, and ecosystems. Full article

As the global ecological environment faces serious challenges and extreme climate change threatens the survival of humankind, the promotion of green development has become the focus for all countries in the world. As one of the world’s major greenhouse gas emitters, China has put forward the “twin goals” of achieving carbon peaking and carbon neutrality and is committed to promoting the green and low-carbon transformation of its cities. As the core of economic and social development, cities are the main source of carbon emissions. In response to the dual challenges of carbon emission control and traffic growth, it is particularly important to promote the development of green transportation. With the acceleration of urbanization, urban traffic pollution is becoming more and more serious. As a zero-emission transportation mode, electric vehicles have become a key way to achieve the carbon peak and carbon neutrality targets. In order to deeply analyze the research status of electric vehicles in the field of the green and low-carbon transformation of urban transportation in China and to explore the research hot spots, evolution trends, and their roles and strategies in the construction of green transportation networks, this paper uses the CiteSpace, VOSviewer, and Tableau analysis tools to review and analyze the 2460 articles and reviews in the Web of Science Core Collection (WOS) and 2650 articles and reviews in the China National Knowledge Infrastructure (CNKI), including the “publication volume and publication trend”, “subject citation path”, “countries cooperation and geographical distribution”, “author cooperation and institution cooperation”, “keyword co-occurrence and keywords clusters”, and the “evolution trend of research hot spots in timeline”. The results show that: (1) Since 2010, the research focus on electric vehicles has gradually increased, and especially in the past three years, the number of such publications has increased significantly. (2) China holds the lead in research output regarding electric vehicles and related fields, but its international cooperation needs to be strengthened. (3) In recent years, the research has focused on “energy transformation”, “energy-saving technology”, “carbon emissions”, “battery recycling”, and other relevant topics. The promotion and development of electric vehicles will continue to usher in new opportunities concerning technological innovation, policy support, and market expansion. Finally, based on the research hot spots and evolution trends of electric vehicles in the field of urban green transportation and low-carbon transportation in China, this paper discusses the key paths and strategies for electric vehicles to promote the transformation of urban transportation in China to green and low-carbon types and looks forward to future research directions. The research in this paper can provide theoretical support and practical guidance for China to promote electric vehicles, build low-carbon cities, and realize green transportation. It is expected to act as a useful reference for relevant policy formulation and academic research. Full article

As an important ecological barrier and economic belt in China, the sustainable development of the Yellow River Basin (YRB) is of great significance to national ecological security and regional economic balance. Based on the coupled and coordinated development analysis of the water–soil–energy–carbon (W-L-E-C) system in the provinces of the Yellow River Basin from 2002 to 2022, this study systematically analyzed the interaction relationship among the various factors through WLECNI index assessment, factor identification, and driving factor exploration. Thus, it fully reveals the spatiotemporal evolution law of regional coordinated development and its internal driving mechanism. It is found that the coordinated development of the W-L-E-C system in different provinces of the Yellow River Basin presents significant spatiotemporal differentiation, and its evolution process is influenced by multiple factors. It is found that the coordination of the YRB presents a significant spatial difference, and Inner Mongolia and Shaanxi, as high coordination areas, have achieved significant improvement in coordination, through ecological restoration and clean energy replacement, arable land intensification, and industrial water-saving technology, respectively. Shandong, Henan, and Shanxi in the middle coordination zone have made some achievements in industrial greening and water-saving technology promotion, but they are still restricted by industrial carbon emissions and land resource pressure. The Ningxia and Gansu regions with low coordination are slow to improve their coordination due to water resource overload and inefficient energy utilization. Barrier factor analysis shows that the water resources utilization rate (W4), impervious area (L4), energy consumption per unit GDP (E1), and carbon emissions from energy consumption (C3) are the core factors restricting coordination. Among them, the water quality compliance rate (W5) of Shanxi and Henan is very low, and the impervious area (L4) of Shandong is a prominent problem. The interaction analysis of the driving factors showed that there were significant interactions between water resource use and ecological protection (W-E), land resource and energy use (L-E), and carbon emissions and ecosystem (C-E). Inner Mongolia, Shaanxi, and Shandong achieved coordinated improvement through “scenic energy + ecological restoration”, cultivated land protection, and industrial greening. Shanxi, Henan, and Ningxia are constrained by the “W-L-E-C” complex obstacles. In the future, the Yellow River Basin should implement the following zoning control strategy: for the areas with high coordination, it should focus on consolidating the synergistic advantages of ecological protection and energy development; water-saving technology and energy consumption reduction measures should be promoted in the middle coordination area. In the low coordination area, efforts should be made to solve the problem of resource overload, and the current situation of low resource utilization efficiency should be improved by improving the utilization rate of recycled water and applying photovoltaic sand control technology. This differentiated governance plan will effectively enhance the level of coordinated development across the basin. The research results provide a decision-making framework of “zoning regulation, system optimization and dynamic monitoring” for the sustainable development of the YRB, and provide a scientific basis for achieving high-quality development of the basin. Full article

Battery energy storage systems (BESSs) are often used in partial-state-of-charge (PSOC) operation due to the desire for flexibility of charge and discharge. Lead–acid batteries are a good candidate to be used in battery energy storage due to their safety, recyclability, and long cycle life; however, the correct battery, cell, and regime should be chosen to ensure effective use. Manufacturers rarely publish data on PSOC performance of their batteries. During PSOC use, the charge acceptance of lead–acid batteries reduces both reversibly and, sometimes, irreversibly as the battery is cycled. Typical dynamic charge acceptance tests target the performance required in car batteries and do not adequately demonstrate the charge acceptance expected in BESS use. This paper demonstrates a representative charge acceptance degradation test which far more closely replicates the charge acceptance degradation seen in real-world PSOC BESS use using partial state of charge, coulomb control, and a charge-factor-controlled full charge. Full charges are shown to reverse the internal resistance associated with partial-state-of-charge operation. This is the case in the Leoch lead–carbon cells and 12 V battery tested. This shows that partial-state-of-charge operation degrades the charge acceptance and increases the internal resistance of a lead–acid battery, although with a charge-factor-based full-charge approach, the charge acceptance could be reset to baseline. Full article

As a low-carbon and efficient energy source, nuclear power plays an indispensable role in China’s pursuit of carbon neutrality. However, existing studies on China’s nuclear energy development often overlook the constraints posed by uranium resources, limiting a comprehensive assessment of the pathways to carbon neutrality. This study incorporates uranium resource constraints into the China Global Energy Model (C-GEM) to analyze in detail the impact of uranium scarcity on China’s nuclear power development, electricity costs, and carbon emissions. Under a scenario of severe uranium resource constraints, the results indicate that nuclear power generation in 2060 is projected to be 35–50% lower than in a high-resource scenario, with nuclear power costs increasing by over 12% and carbon prices rising by approximately 2%. Without robust management of the uranium supply, the development of nuclear power may be constrained, hindering China’s ability to achieve its carbon neutrality targets. Therefore, this study suggests that China’s nuclear energy policies should focus on strengthening uranium resource security through enhanced domestic and international exploration, investing in advanced fuel recycling and high-efficiency reactor technologies, and integrating these measures into the broader low-carbon energy framework to ensure the sustainable development of nuclear power. Full article

Hydrogen is a promising alternative to fossil fuels, but its efficient storage presents significant challenges. Polymer composite vessels, especially those made from carbon fiber-reinforced plastic (CFRP), are gaining attention, due to their high strength-to-weight ratio for storing compressed or cryogenic hydrogen. The latest Type V tanks, which lack internal liners, rely solely on fiber composites for both structural integrity and gas containment, enhancing the storage volume-to-weight ratio and supporting recycling. However, this linerless design faces the challenge of preventing gas permeation. Epoxy resins, widely used in aerospace carbon fiber-reinforced composites (CFRCs), offer excellent processability and load-bearing capabilities. The addition of high-aspect-ratio nanofillers can enhance the gas barrier properties, which are essential for preventing hydrogen leakage, while also improving the mechanical, electrical, and thermal properties of the nanocomposites. This study focuses on epoxy-based composites with expanded graphite, aiming to optimize their physical properties and processing for Type V tanks, using a rheological framework to evaluate their processability and multifunctionality in transport applications. Full article