Search Results (822)

Background: This systematic review evaluates the evidence on sustainable practices in dentistry. It focuses on effective measures, innovative technologies, strategies for reducing the carbon footprint, life cycle assessments (LCA), attitudes toward “green” dentistry, and educational approaches. Methods: A systematic search was conducted in five databases (Cochrane Library, Embase, LILACS, MEDLINE via PubMed, and Scopus) without language restrictions in accordance with PRISMA. The review was registered in PROSPERO (CRD420251056821). Results: A total of 2395 records were identified; after removing 394 duplicates, 2001 remained for screening. After title and abstract screening, 154 full-text articles were evaluated, of which 51 studies were included. The included studies addressed life cycle assessments of dental materials, sustainable clinical practices, and educational measures. Environmentally friendly materials and procedures, such as reusable personal protective equipment and water-saving technologies, demonstrate significant potential for reducing environmental impact. Despite generally high acceptance among dentists and patients, implementation is often limited by financial and knowledge-related barriers. Conclusions: The implementation of sustainable materials and procedures is crucial for reducing environmental impact. Equally important are the integration of ecological content into education and appropriate financial and political frameworks to promote sustainable dentistry. Full article

Combining oxygen-enriched combustion CO₂ capture technology and CO₂ hydrogenation with methanol technology, a new power–chemicals cogeneration (PCC) design is proposed for thermal power stations with CO₂ capture and utilization under the power-to-liquid concept. For material integration, CO₂ from an oxygen-enriched thermal power station and H₂ from water electrolysis using renewable power serve as raw materials for the methanol production process. O₂ from water electrolysis using renewable power is supplied to the oxygen-enriched thermal power station; thus, electricity can be saved and investment in an air separation unit can be beneficial. For energy integration, power for gas compression and heat for methanol rectification in the methanol production process are supplied by an oxygen-enriched thermal power station. The energy released from the methanol production process is fully recovered for extra power generation. Energy analysis results show that a high CO₂ capture and utilization ratio, which is defined as the ratio of the captured and utilized CO₂ to the total CO₂ generation, of 78.1% could be achieved. By integrating the system in a 600 MW thermal power station, the net power generation and methanol production of the proposed design reaches 473.1 MW and 56.1 kg/s, respectively. Economic analysis results show that the power cost is estimated to be 62.8 $/MWh, which has great market competitiveness compared to the conventional thermal power station with CO₂ capture. Due to the saved material expense and power and heat expense, the methanol cost is reduced from 1.33 $/kg to 1.20 $/kg. The H₂ expense by water electrolysis using renewable power has a decisive influence on the methanol cost. Full article

Indoor swimming pools are energy- and water-intensive facilities. Advanced technologies enable water recovery and eliminate heat consumption by recirculating water used for filter backwashing. The aim of this article is to assess the water and energy savings resulting from the use of backwash water from swimming pool filters through the implementation of a modern technological system. The results of the analyses allow for an assessment of the benefits depending on the assumptions adopted in the national regulations regarding swimming pools in two neighboring countries: Poland and the Czech Republic. The temperature of the water supply to the swimming pool system has a significant impact on heat consumption, as a 7 °C difference between water temperatures in Poland and the Czech Republic causes a 50% increase in heat consumption. The high efficiency of the recycling systems allows for water savings of up to 30 m³ per day. In the case of pools with a water temperature of 26 °C, the energy savings range from 645 to 967 GJ per year, depending on the fresh water temperature. Implementing the system has enormous benefits in the decarbonization process, reducing CO₂ emissions by 80%. Full article

Water scarcity poses a major constraint on efficient and sustainable grain production in China. Drawing on the New New Trade Theory and Induced Technological Innovation Theory, this study empirically investigates the relationship between cost competition from grain imports and water use efficiency in grain production from a virtual water trade perspective. The results show the following: (1) From 2003 to 2020, China’s overall grain production water use efficiency exhibited an upward trend, with the Huang-Huai-Hai and Northeast regions increasing by 66.35% and 28.49%, respectively. (2) Cost competition from grain imports can force improvements in water use efficiency. For every 1 billion tons of virtual water saved through imports, water use efficiency increases by 0.008. However, when annual virtual water savings exceed 11 billion tons, import competition surpasses a critical threshold. Due to technological and facility constraints, even previously efficient producers cannot further improve efficiency in the short term, and the allocative efficiency of production factors is undermined, leading to a decline rather than an improvement in water use efficiency. (3) The positive effect of import cost competition on water use efficiency is stronger in northern regions and non-major grain-producing areas. (4) Import cost competition improves water use efficiency by reducing domestic grain production profits. This study validates the applicability of the pro-competitive effect of trade and induced technological innovation in grain trade, expands the research boundaries of virtual water trade, and provides policy insights for improving China’s grain production water use efficiency. Full article

This paper presents a case study demonstrating the operation of a 50 kVA three-phase variable-speed diesel generator at a Spanish Antarctic research base, located in an area of special ecological and environmental value, under conditions of extreme humidity and temperature. It verifies the fuel savings achieved through the use of variable-speed technology compared to standard, constant-speed generators. Furthermore, given that the price of fuel is significantly higher due to the high cost and complexity of transporting it to the base, the fuel savings at the base represent a huge logistical advantage, quite apart, of course, from the environmental benefits of such savings. A key feature of the equipment presented is that it has a system for recovering waste heat from the combustion engine, which, when integrated into the base’s hot water system, is used to increase the domestic hot water capacity, adding value to the machine whilst also delivering fuel savings. Full article

To measure the scale of agricultural water transfer (AWT) from the perspective of food security, this paper establishes an integrated framework for quantifying its actual scale, theoretical transferable scale, and deviation. Based on panel data from 2001 to 2023 of five cities (Anyang, Hebi, Xinxiang, Jiaozuo, Puyang) of the Wei River Basin in Henan Province, China, the actual transfer scale is derived by comparing agricultural water right allocations with net crop irrigation requirements calculated via the FAO 56 Penman Monteith formula; the theoretical transferable scale is estimated using a translog production function grounded in factor substitution theory. By contrasting the two scales, deviations and excessive transfer scenarios are identified. The results show that (1) actual AWT occurred in 59.13% of the city–year observations, exhibiting clear phase-based fluctuations, with positive transfer scale ranging from 0.046 to 13.983 × 10⁸ m³. The largest positive transfer occurred in Puyang in 2002, and Puyang, Jiaozuo, and Xinxiang were the main outflow areas. Factor combinations could release transferable water in 45.22% of the city–year observations, wherein pesticide/fertilizer, agricultural machinery, and grain sown area serve as the main substitutes. Theoretical transferable scale ranged from −60.150 to 186.374 × 10⁸ m³, with a mean of 1.718 × 10⁸ m³ and a median of −0.108 × 10⁸ m³, indicating unstable factor-substitution capacity. (2) Excessive transfer was identified when the actual transfer scale was positive and exceeded the theoretical transferable scale. Under this criterion, 47.82% of observations were excessive transfers, 11.33% were reasonable transfers, and 40.85% showed no transfer. Jiaozuo and Puyang were the core excessive transfer areas, each showing excessive transfer in 16 of the 23 years, while Xinxiang has shown a rising trend in recent years; Anyang, by contrast, effectively controls excesses through water saving technologies. The findings highlight the need for dynamic monitoring, city-specific regulation, and advanced water-saving technologies to balance water allocation with food security. Full article

The temporal variations of evapotranspiration (ET) and its controlling factors occur across time scales ranging from seconds to decades, with significant differences in the lag effects of ET drivers under varying water conditions. Therefore, identifying the dominant time scales of the relationships between ET and its controlling factors under varying water conditions is crucial for optimizing irrigation strategies of crops grown in a greenhouse. In our study, we utilized two years of continuous lysimeter observations of greenhouse tomato ET, and applied two water treatments: well-irrigated (0.9E_pan, E_pan is the cumulative pan evaporation) and deficit-irrigated (0.5E_pan). Wavelet transform technology served as the core method to systematically examine the temporal variations of ET and its controlling factors. Observations indicated that the power spectra of ET featured pronounced peaks at daily and seasonal scales. The cospectra between ET and soil water content for greenhouse tomato revealed strong temporal correlation at 2~5 day scales, confirming the regulatory effect of irrigation cycles on ET. Moreover, ET variations were largely synchronous with net radiation, with ET lagging net radiation but leading vapor pressure deficit and air temperature at daily scales. In addition, significant disparities in phase angles between ET and individual meteorological variables were identified under 0.9E_pan and 0.5E_pan water conditions. Partial wavelet coherence revealed that net radiation was the primary meteorological driver of greenhouse tomato ET across multiple time scales, particularly at the daily scale, followed by vapor pressure deficit. These findings provide scientific evidence for selecting appropriate ET models at different time scales and offer valuable insights for optimizing water-saving irrigation for crops grown in greenhouses. Full article

China faces a pronounced contradiction between the supply and demand of agricultural water resources, coupled with relatively low efficiency in agricultural water use. It is imperative to develop modern, efficient water-saving agriculture to further unlock its water-saving potential. To enhance the adoption rate of water-saving irrigation technologies among family farms, this study delves into the influencing mechanisms behind citrus family farms’ willingness to embrace such technologies, adopting a dual perspective of self-interest and altruism. This is achieved by integrating the Theory of Planned Behavior (TPB) and the Norm Activation Model (NAM). Utilizing data from a 2024 survey of 403 citrus family farms in Sichuan Province, a structural equation model is employed for analysis. The findings reveal that (1) economic expectations and efficiency evaluations positively influence the willingness to adopt water-saving irrigation technologies in citrus family farms, whereas technical risks exert a negative impact. (2) The pathway influencing the adoption intention can be summarized as “consequence awareness → responsibility attribution → personal norms → adoption intention,” with the impact of consequence awareness on personal norms failing to achieve statistical significance. (3) Responsibility attribution mediates the relationship between consequence awareness and personal norms, while personal norms mediate the relationship between social norms and adoption intentions. Consequently, the government should implement publicity and guidance initiatives, enhance understanding of technological benefits, strengthen service support, mitigate perceptions of technological risks, organize educational and training programs, and boost confidence in technology adoption. By adopting a multifaceted approach, the government can foster the formation of a willingness to adopt water-saving irrigation technologies among citrus family farms. Full article

Accurate, high-resolution irrigation-related spatial information is paramount to diverse applications, including water resources management, food security, and agricultural planning. To address this need, our study leveraged machine learning algorithms and integrated multi-source data to extract and analyze land use types and spatiotemporal dynamics of irrigated farmland across provinces in the lower reaches of the Yellow River Basin over the 2008–2022 period. The results indicate that cultivated land remained dominant and largely stable, although localized losses occurred in peri-urban areas due to urban expansion. Construction land increased significantly, particularly in Shandong where it expanded by more than 15%, while forest and grassland areas grew under national ecological programs. The Random Forest (RF) algorithm achieved robust performance in identifying irrigated farmland, with overall accuracy exceeding 85% and regression with statistical irrigation data yielding R² values above 0.9 over the past 15 years at the city level. Spatiotemporal analysis showed strong variability in Henan, with irrigated area declining by 8–12% during drought years and recovering in wetter years, while Shandong experienced relative stability but a gradual 5% decline since 2015, driven by groundwater depletion and stricter regulation. The findings suggest irrigation expansion has reached near-saturation, given stable cultivated land and continuous improvements in water use efficiency. Future strategies should prioritize water use efficiency, water saving technologies, and equitable allocation to ensure sustainable agricultural development. Full article

To investigate the effects of water-saving irrigation and different straw retention methods on soil CH₄ and N₂O emissions from paddy fields in cold regions and their potential underlying mechanisms, a field experiment was conducted in Qing’an City, Heilongjiang Province. Two water management regimes were set, combined with four straw retention treatments. The static chamber-gas chromatography method was used to monitor CH₄ and N₂O emission fluxes during the entire rice growth period. Meanwhile, soil pH, oxidation–reduction potential (Eh), dissolved oxygen (DO), and dynamic changes in carbon and nitrogen substrates were measured, and the global warming potential (GWP) and greenhouse gas emission intensity (GHGI) were comprehensively evaluated. The results showed that controlled irrigation significantly increased soil dissolved oxygen content and oxidation–reduction potential. Compared with conventional flooding irrigation, total CH₄ emission decreased by more than 50%, while N₂O emission increased by 1.5–2.5 times, exhibiting an obvious divergent correlation with the two gas emission fluxes. Among different straw retention methods, organic fertilizer returning and direct straw returning significantly promoted CH₄ emission by supplying easily decomposable organic carbon. In contrast, biochar, due to its stable carbon structure and favorable pore properties, inhibited CH₄ emission without significantly stimulating N₂O emission. The treatment of controlled irrigation combined with biochar returning (CB) achieved the lowest global warming potential and greenhouse gas emission intensity at 7230.82 kg CO₂-eq/hm² and 0.8054 kg CO₂-eq/kg, respectively, while maintaining high rice yield. Path analysis based on soil physicochemical properties and emission fluxes further revealed that Eh and DO were significantly negatively correlated with CH₄ emission but positively correlated with N₂O emission. Path inference from flux and substrate data indicated that carbon and nitrogen availability were the key factors limiting the denitrification process. In conclusion, the combined application of controlled irrigation and biochar returning can realize the synergistic effect of stable yield and emission reduction in cold-region paddy fields by improving soil aeration and regulating the transformation of carbon and nitrogen substrates, providing a scientific basis for establishing a green and low-carbon rice production technology system for black soil in cold regions. Full article

Biogas produced from the anaerobic digestion of organic matter holds much promise as a renewable energy source for decentralized systems. However, raw biogas contains substantial volumes of carbon dioxide, hydrogen sulfide, water vapor, and other trace impurities. These impurities can reduce the calorific value of biogas and limit its direct use for household energy needs. Purifying biogas to high-grade biomethane (≥95%) is therefore important to improve methane (CH₄) content and combustion characteristics. This is a guarantee of its safe utilization in domestic appliances, including cooking, heating, lighting, and electricity generation. This article reviews and evaluates novel approaches for upgrading raw biogas into high-purity biomethane that can offset natural gas in domestic applications. It further examines recent developments in conventional and innovative upgrading technologies such as water scrubbing, chemical scrubbing, pressure swing adsorption, membrane separation, cryogenic separation, and biological upgrading. Particular emphasis is placed on low-cost and small-scale solutions suitable for off-grid or mini-grid rural energy systems. Moreover, the role of process optimization, intelligent monitoring, and data-driven control methods in increasing CH₄ recovery and process efficiency is discussed. Despite their relatively high capital costs and energy needs, conventional technologies such as water scrubbing, pressure swing adsorption, and membrane technology continue to dominate biogas purification systems. The findings show that coupling advanced separation technologies, including cryogenic separation, biological upgrading, and hybrid technologies, with optimized process control can significantly improve CH₄ purity, save energy use, and enhance the overall consistency of biogas purification systems. These innovative strategies have strong potential to promote the full-scale adoption of biomethane as a clean, sustainable, and affordable energy source for decentralized applications, particularly in the developing world. Full article

Background and Aims: The global rise of chronic kidney disease (CKD) has led to a rapid expansion of dialysis services, which, although life-saving, are associated with substantial environmental costs. This study aims to analyze the environmental impacts of dialysis therapies and identify pathways toward more sustainable practices. Methods: This study conducts a comprehensive and integrative literature review on research in renal replacement therapy, adopting the PRISMA-ScR procedure to analyze papers published between 2005 and 2023. Results: The literature primarily focuses on four environmental dimensions: carbon emissions, water consumption, energy use, and waste generation. Dialysis therapies—particularly hemodialysis—are resource-intensive and contribute significantly to environmental degradation though repeated treatments, transportation requirements, and high consumption of materials and energy. Conclusions: Sustainable dialysis can be promoted through the adoption of green technologies, improved waste management, and policies focused on energy and resource efficiency. While current practices are environmentally demanding, feasible strategies exist to reduce their ecological footprint and align nephrology care with global sustainability goals. Full article

This study systematically investigated the regulatory effects of different types of superabsorbent polymers (SAPs) on the growth and physiological characteristics of pakchoi (Brassica rapa subsp. chinensis) under drought stress. A pot-controlled experiment was conducted with two stress levels (severe drought and mild drought) and four SAP application ratios (0%, 0.25%, 0.5%, 0.75%). The acrylamide-based SAPs included a self-developed attapulgite clay hydrogel (ACH) and two commercially available mainstream SAPs. The results indicated that: (1) All SAP treatments mitigated the inhibitory effects of drought stress on pakchoi growth to varying degrees, with the 0.5% ACH application showing the most significant effect. Under severe drought, this treatment significantly increased leaf area, shoot fresh weight, and root fresh weight by 184.6%, 127.8%, and 24.6%, respectively, compared to the drought-stressed control without SAP. (2) At the physiological response level, ACH significantly optimized the osmotic adjustment system of pakchoi, manifesting as a significant 53.2% decrease in proline content and a significant 60.1% increase in soluble sugar content. Concurrently, it effectively maintained cell membrane stability, reducing malondialdehyde (MDA) content by a significant 51.6%, and effectively regulated the antioxidant defense system, modulating the activities of key antioxidant enzymes (SOD, CAT, and POD) to prevent oxidative damage. This study reveals that SAPs can effectively alleviate drought stress in pakchoi. Even under severe drought stress, leaf fresh weight reached approximately 67.99% of the normal level. An application rate of 0.5% ACH is identified as an efficient and recommended dose, offering a promising technological option for water-saving and sustainable vegetable production in arid and semi-arid regions. Full article

As China advances high-quality agricultural development, promoting green production among farmers has become an important policy priority. Using survey data from 1787 rice farmers in seven major rice-producing provinces in southern China, this study examines whether enterprise-led contract farming can promote farmers’ green production behavior. Green production behavior is measured by a composite index based on six practices, including green control technology, soil testing and formulated fertilization, organic fertilizer substitution, water-saving irrigation, agricultural film recycling, and straw return. Empirical analysis results show that enterprise-led contract farming can significantly promote farmers’ green production behavior. Further analysis suggests that food safety certification, planting technology training, and lower perceived price volatility are important pathways through which contract farming is linked to green production practices. The promoting effect is weaker among older farmers, stronger for farmers cultivating land with medium soil fertility, and more pronounced among small-scale rice farmers. These findings highlight the role of enterprise-led contract farming in promoting farmers’ green production and offer policy implications for encouraging wider participation in green production practices. Full article

This paper presents a systematic review of compression casting concrete (CCC) based on a comprehensive literature retrieval from the Web of Science, covering publications from 2020 to 2026. CCC applies pressure on fresh concrete to expel excess internal water and air, driving the cement paste to fully penetrate the aggregate pores, which can significantly optimize the micro- and macro-properties of concrete. With environmental friendliness and resource-saving merits, CCC has become a global research hotspot in the field of civil engineering and construction. Research contributions have been made by scholars from China, Australia, Pakistan, France, the UK, India, Italy and other regions. This paper systematically elaborates the basic principles and core advantages of the compression casting technology, focusing on the analysis of key research directions, including mechanical properties, ductility improvement, durability, solid waste resource utilization (waste rubber particles, recycled concrete aggregates), compression-casting-reinforced concrete members and special-purpose preparation equipment. It analyzes the advantages and disadvantages from both micro and macro perspectives and demonstrates the engineering application feasibility and development potential of this technology. It is concluded that the mechanical properties of CCC with compressive strength exceeding 60 MPa still require further in-depth investigation, compression casting technology improves the utilization efficiency of red mud, durability research on CCC remains insufficient, and specialized equipment for large-scale reinforced concrete CCC members needs further development. Full article