Search Results (49,612)

Urban carbon emissions significantly contribute to climate change, exacerbating environmental issues such as global warming. Understanding carbon metabolism is vital for identifying key emission sources and implementing targeted mitigation strategies. This study presents an innovative carbon metabolism analysis framework that integrates an ecological network analysis (ENA) with land use dynamics, enriching the theoretical system and providing policy recommendations for sustainable urban development. We investigated carbon metabolism in the Beijing–Tianjin–Hebei Urban Agglomeration (BTHUA) from 2000 to 2020 using land use and statistical data. The ENA method quantified the ecological relationships between land use compartments. Our findings revealed that industrial and transportation land exhibited the highest carbon emission density, while forest land demonstrated the highest carbon sequestration density. Notably, the negative net horizontal carbon flow indicated that land use changes exacerbated the disorder of carbon metabolism. The increasing mutualism index suggested a reduction in the negative impacts of land use changes on carbon metabolism. This study highlights the importance of spatial planning in transforming ecological relationships and provides a comprehensive understanding of carbon metabolism dynamics influenced by land use changes. The insights gained can inform effective mitigation strategies in the BTHUA and similar urban agglomerations, ultimately contributing to sustainable urban development. Full article

Carbonyl sulfide (COS), an organosulfur compound commonly present in industrial gases, poses significant challenges for environmental protection and industrial processes due to its toxicity. This paper reviews recent advancements in the development of catalysts for COS hydrolysis, emphasizing the effects of various supports and active components on catalyst performance, as well as the mechanisms underlying the hydrolysis reaction. Traditional supports like γ-Al₂O₃ demonstrate high activity for COS hydrolysis but are susceptible to deactivation. In contrast, novel supports such as activated carbon, TiO₂, and ZrO₂ have garnered attention for their unique structures and properties. The incorporation of active components, including alkali metals, alkaline earth metals, transition metals, and rare earth metals, significantly enhances the hydrolysis efficiency and resistance to deactivation of the catalysts. Additionally, this paper outlines three primary mechanisms for COS hydrolysis: the alkali-catalyzed mechanism, the Langmuir–Hinshelwood model, and the Eley–Rideal model mechanism, as well as the thiocarbonate intermediate mechanism, which collectively elucidate the conversion of COS into the H₂S and CO₂ catalyzed by these systems. Future research efforts will concentrate on developing high-activity, high-stability, and cost-effective COS hydrolysis catalysts, along with a more in-depth exploration of the reaction mechanisms to facilitate the efficient removal of COS from industrial emissions. Full article

This paper examines Connected Smart Green Buildings (CSGBs) in Burnaby, BC, Canada, with a focus on townhouses with one to four bedrooms. The proposed model integrates sustainable materials and smart components such as recycled insulation, Photovoltaic (PV) solar panels, smart meters, and high-efficiency systems. These elements improve energy efficiency and promote sustainability. Operating in island mode, CSGBs can function independently of the grid, providing resilience during power outages and reducing reliance on external energy sources. Real data on electricity, gas, and water consumption are used to optimize load management under isolated conditions. Electric Vehicles (EVs) are also considered in the system. They serve as energy storage devices and, through Vehicle-to-Grid (V2G) technology, can supply power when needed. A hybrid Machine Learning (ML) model combining Long Short-Term Memory (LSTM) and a Convolutional Neural Network (CNN) is proposed to improve the performance. The metrics considered include accuracy, efficiency, emissions, and cost. The performance was compared with several well-known models including Linear Regression (LR), CNN, LSTM, Random Forest (RF), Gradient Boosting (GB), and hybrid LSTM–CNN, and the results show that the proposed model provides the best results. For a four-bedroom Connected Smart Green Townhouse (CSGT), the Mean Absolute Percentage Error (MAPE) is 4.43%, the Root Mean Square Error (RMSE) is 3.49 kWh, the Mean Absolute Error (MAE) is 3.06 kWh, and $R^2$ is 0.81. These results indicate that the proposed model provides robust load optimization, particularly in island mode, and highlight the potential of CSGBs for sustainable urban living. Full article

Methane (CH₄), the second-largest greenhouse gas contributing to global warming, has a high warming potential despite its short atmospheric lifespan. Inner Mongolia, due to its high carbon and energy consumption industries, faces significant methane emission challenges. This study uses TROPOMI satellite data (February 2019 to December 2022) to analyze the long-term trends and spatial distribution of methane in Inner Mongolia. The results indicate significant spatial heterogeneity in the methane concentration distribution in Inner Mongolia, China. Higher methane concentrations are observed in the southeastern regions, whereas the central regions exhibit relatively lower concentrations. Temporally, the methane concentrations show an increasing trend with seasonal peaks from late August to early September. Using multiple stepwise regression and geographically weighted regression (GWR) methods, the study identifies the key factors influencing methane concentrations. Increased precipitation and soil temperature, along with intensified human activity, contribute to higher methane levels, while rising surface temperatures and increased vegetation suppress methane concentrations. The GWR model provides a better fit compared to the traditional methods, especially in regions with higher methane levels. This research offers insights for developing strategies to mitigate methane emissions and supports China’s emission control targets. Full article

This study evaluates the impact of foreign direct investment (FDI), per capita GDP, renewable energy consumption, and urbanization on India’s $C{O}_2$ emissions over the period 1990–2023. In the context of rapid economic growth and urbanization, India faces major challenges related to environmental sustainability. Using the ARDL (Autoregressive Distributed Lag) model and the Environmental Kuznets Curve (EKC), this research analyzes the complex relationships between these factors and $C{O}_2$ emissions. The results highlight the existence of an N-shaped EKC curve with two inflection points at GDP values. This study highlights the essential role of renewable energy consumption in reducing emissions and improving access to electricity in promoting sustainable development. The findings provide valuable insights into economic and energy policies, highlighting the need to balance economic growth with environmental protection. Full article

FT blends derived from biomass have been confirmed to benefit reductions in GHG and particulate matter (PM). An improvement in combustibility is predicted to reduce fuel consumption and lead to further emission reduction. Various FT fuel blends (7%, 10%, 23%, and 50%) were assessed in terms of their potential for energy savings and emission reduction in a ZF850 jet engine. The engine performance, including the thrust, fuel consumption, emissions, exhaust gas temperature (EGT), acceleration, and deceleration, was investigated in terms of the whole thrust output, while combustor performance parameters, including EI_UHC, EI_PM2.5, EI_CO, EI_Nox, and combustion efficiency, were also discussed. The benefit gained in engine performance was nonlinearly related to the blend ratio, which indicated that the available FT blends required appropriate fuel properties coupled with the engine design. According to the superior improvements derived from the 7% FT fuel blend and 23% FT fuel blend, an appropriate lower C/H ratio and higher combustion efficiency with low PM emissions led to a reduction in fuel consumption. Through global sensitivity analysis, changes in the thrust-specific fuel consumption (TSFC) and the thrust and combustion efficiency with various fuel properties were captured. These can be classified as engine-influenced and fuel-influenced (EIFI) parameters. EI_CO and EI_NOx are mainly dependent on the combustor and engine design and can be categorized as engine-influenced and fuel-less-influenced parameters (EIFLI), while EI_UHC and EI_PM2.5 can be categorized as EIFI parameters. The results of this work could extend our understanding of the impact of FT blends on engine performance and GHG reduction. Full article

In this study, gaseous element mercury (GEM) and gaseous oxidized mercury (GOM) in the atmosphere were continuously observed at a minute resolution from 1 April 2019 to 31 December 2020 in urban Xi’an, the largest central city in Northwestern China. The concentrations of GEM and GOM drastically fluctuated within the ranges of 0.022–297 ng/m³ and 0.092–381 pg/m³, showing average values of 5.78 ± 7.36 ng/m³ and 14.2 ± 20.8 pg/m³, respectively. GEM and GOM showed a decreasing trend of 0.121 ng/m³ and 0.472 pg/m³ per month, respectively, which we believe was mainly caused by anthropogenic sources, especially by a reduction in coal-fired emissions, rather than meteorological factors. The significant positive correlation between GEM and PM_2.5, SO₂, NO₂, and CO, as well as Cr, As, and Pb in PM_2.5 also proves that. GEM showed a higher concentration at nighttime than daytime, while an M-shaped diurnal trend was observed for GOM. The hazard quotient of GEM for both males and females decreased at a rate of 0.003 per month, and children aged 2–5 were more sensitive to non-carcinogenic health risks. The changing trends, controlling factors, and human health risks of Hg in the atmosphere are necessary and crucial to study for improving our understanding of the impacts of Hg in Northwestern China. Full article

The drying of insects is an important step in their processing. This research aimed to investigate the impact of a pulsed electric field (PEF), immersion in ethanol (EtOH), and combined (immersion in EtOH followed by PEF) treatment on the convective drying process, the emission of CO_2, and the quality of the dried insects with regard to such elements as water content and activity, rehydration and hygroscopic properties, optical properties, internal structure, and microbiological quality. In applying a PEF, the drying time was made longer (up to 21%), but the rehydration and hygroscopic properties were improved (about 15–16.5% and 8.3–21.7%, respectively) compared to the untreated sample. Using a PEF prior to EtOH treatment improved the rehydration properties (about 3.9–5.9%), while the hygroscopicity was slightly lower compared to the PEF-treated samples. Furthermore, immersion in ethanol (both alone and after PEF) provided a lighter color of dried insects and more outstanding microbiological quality, e.g., the absence of water-borne and food-borne pathogens and anaerobic spore-forming bacteria. This study revealed that combined pretreatment seems to be the most promising method for insects as regards obtaining better rehydration and comparable hygroscopic properties, as well as an attractive color compared to untreated insects, and, above all, in ensuring suitable microbiological quality. Full article

Frequent coal mine gas disasters pose significant threats to the safety of miners and the continuity of coal mining operations. Understanding and mastering the patterns of gas occurrence is the foundation for controlling gas outbursts. This study, drawing on previous theories, research, and practical coal mine production data, analyzes the structural characteristics of the Kaiping syncline, with particular emphasis on the structural differentiation at its northeastern uplifted end. The study examines how gas generation and storage are influenced by progressively layered structures and their effect on coal mine gas management. The results indicate that the Kaiping syncline has a NE-SW axial orientation, which gradually shifts to an asymmetric syncline with a nearly EW trend, rising towards the northeastern end. At the turning end, the strata on the northwest limb are steep—locally vertical or overturned—gradually transitioning into the gentler southeast limb with dips of 10° to 30°, further complicated by a series of sub-parallel secondary folds. The gas formation process in coal seams has undergone multiple stages, regulated by structural burial and thermal evolution. The current gas storage characteristics result from the combined effects of these structural factors. The Kaiping syncline can be divided into two gas zones: a high-gas zone in the northwest limb and a shallow low-gas zone paired with a deep high-gas zone in the southeast limb. At the turning end, structural differentiation results in significant variations and gradations in the gas storage conditions of the coal seam. This differentiation directly causes a transition from coal and gas outburst mines in the northwest limb to low-gas mines in the southeast limb, highlighting the significant influence of structural factors on gas generation, preservation, and mine gas emissions. This study integrates theoretical analysis with measured data to enhance the understanding of structural evolution and its influence on gas storage. It offers guidance for preventing coal seam gas disasters and ensuring the safe production of coal mines in the Kaiping coalfield. Full article

Exhaust gas recirculation (EGR) systems, in addition to catalytic reactors, are now widely used in reciprocating internal combustion engines to reduce oxides of nitrogen (NOx) in the exhaust gases. They are characterized by the fact that part of the exhaust gas from the exhaust manifold is recycled and directed to the intake manifold through a special valve. This valve, depending on the current engine load and velocity, doses an appropriate amount of exhaust gas which, with each new charge, is fed to the individual engine cylinders. In addition, the positioning of the valve has a significant effect on the formation of nitrogen oxides in the exhaust gas from individual engine cylinders, which is due to the uneven distribution of exhaust gas into the intake manifold channels. Tests were carried out on a power unit equipped with a symmetrical intake manifold with a centrally located EGR valve. The article presents the results of tests on a system in which each cylinder was supplied with a separate EGR valve. This solution made it possible to charge each cylinder with the same mass of recirculated exhaust gas, which was dependent on engine velocity and load. The exhaust nitrogen oxides emissions were measured for the originally manufactured system and compared with the multi-valve system. The results confirmed the need for individual selection of the dose of recirculated exhaust gas for particular cylinders, as the multi-valve system equalized the levels of nitrogen oxides emissions in the exhaust gases coming from individual cylinders of the internal combustion engine. Full article

The combustion of renewable solid fuels, such as biomass, is a reliable option for heat and power production. The availability of biomass resources within urban areas, such as tree leaves, small branches, grass, and other green city waste, creates an opportunity to valorize such resources. The energy densification of such resources using hydrothermal carbonization (HTC) and pelletization of the carbonized material could create a new generation of domestic boiler biofuel. However, combustion efficiency and emission assessments should be carried out for HTC pellets. The primary objective of this study is to assess HTC pellets, provided by a waste upgrade company, in terms of kinetics, combustion efficiency, and emissions, taking as reference base ENplus A1 certified softwood pellets. Therefore, thermogravimetric analysis and combustion tests were conducted for both fuels to achieve this. It was observed that a third peak of the burning rate during the solid carbon oxidation of HTC pellets indicated a high activation energy. Combustion tests showed a 7% increase in boiler efficiency for HTC pellets compared to softwood pellets. However, higher particulate matter (PM), NO_x, and CO emissions were recorded during the HTC pellets test. The results suggest that optimizing the air/fuel ratio could further improve the performance of HTC pellets in domestic boilers. Full article

Landslides, as natural hazards, have far-reaching impacts beyond their immediate effects on human lives and infrastructure; landslides disrupt both carbon storage and ecosystem stability, and their role in the global carbon cycle cannot be underestimated. This study delves into the complex relationship between landslides and carbon stocks such as, in particular, soil organic carbon (SOC) and above-ground biomass (AGB), and outlines the spatial relationship between different types of landslides, soil organic carbon (SOC), and the carbon cycle, underscoring the importance of understanding these interconnections for environmental sustainability and climate change mitigation efforts. By employing machine learning algorithms on the Google Earth Engine platform, landslide susceptibility maps were created for different landslide types across Italy, and their spatial patterns with SOC accumulation were analyzed using the Python environment. The findings reveal a nuanced relationship between landslide hazard levels and SOC dynamics, with varying trends observed for different landslide types. In addition, this study investigates the potential impact of large-scale landslide events on carbon sequestration in the short term via a case study of the May 2023 landslide event in the Emilia Romagna region of Italy. The analysis reveals a substantial reduction in above-ground biomass by 35%, which approximately accounts for the loss of 0.133 MtC, and a decrease in SOC accumulation in 72% of the affected areas, indicating that landslides can transform carbon sinks into carbon sources, at least in the short term, and suggested that carbon released from extreme landslide events at a larger scale needs to be accounted for in regional or national carbon emissions. This research underscores the importance of considering landslides in carbon cycle assessments and emphasizes the need for sustainable land management strategies to protect and enhance carbon sinks, such as forests and healthy soils, in the face of increasing natural hazards and climate change impacts. Full article

The calamondin (Citrus × microcarpa) is highly valued for its ornamental appeal and rich aromatic compounds, making it suitable for therapeutic gardens and widely applicable in the cosmetics, food, pharmaceutical, and perfume industries. Despite its importance, there is a lack of research on its floral volatiles. This study utilized headspace solid-phase microextraction gas chromatography–mass spectrometry (HS–SPME–GC–MS) to detect the volatile organic compounds (VOCs) of calamondin at different floral developmental stages: bud (BS), half-open (HS), full bloom (FS), and senescence (SS). Multivariate statistical analysis was employed to elucidate the aromatic characteristics. The results identified 67 VOCs across the four stages, including forty-eight terpenoids, six esters, five aromatics, four aldehydes, one olefin, one alcohol, and two others. Thirty-three VOCs were common across all stages, while BS, HS, FS, and SS had three, three, four, and nine unique VOCs, respectively. The total VOC content increased initially and then decreased as the flowers developed, with terpenoids being the predominant compounds, accounting for over 90% of the total emissions at all stages. Principal component analysis and hierarchical cluster analysis confirmed significant differences in VOC profiles at different stages. Partial least squares discriminant analysis identified five VOCs with variable importance in projection (VIP) values greater than one, including limonene, linalool, β-pinene, germacrene D, and β-ocimene, indicating their varying emission levels across stages. These findings enhance our understanding of the VOC characteristics of calamondin flowers and provide a scientific basis for further ornamental and industrial applications. Full article

We know little about how parasitoids of herbivorous insects use herbivore-induced volatile organic compounds (VOCs) to locate potential hosts on saplings in forests, and how this depends on tree composition. Therefore, we performed an experiment in a forest in Poland where we placed pairs of oak saplings (Quercus robur or Q. petraea) in neighborhoods dominated by oak, beech, or pine trees. We treated one sapling in each pair with the phytohormone methyl jasmonate, which triggers induced responses in plants. We measured the VOC emissions of thirty-six saplings and placed Malaise traps with five of the pairs. We counted the parasitoids in the ten Malaise samples and identified them using DNA metabarcoding. We used parasitoids reared from oak-feeding caterpillars to estimate which species are associated with oaks. The two species of oak differed in both the proportions of VOCs and the specific VOCs that were elevated following the application of methyl jasmonate. We did not detect any overall effects of treatment on parasitoid abundance or community composition. However, some parasitoid species that were associated with oaks appeared to be attracted to elevated emissions of specific induced VOCs. The parasitoid communities differed significantly between sites and showed marginally significant differences between neighborhoods. Overall, our results suggest that parasitoids in the understory are affected by tree composition of the canopy, but the effects of VOC emissions are limited. Full article