Search Results (507)

To explore the hydrogeochemical characteristics and dominant water–rock interaction processes of thermal water in Lindian geothermal field (northern Songliao Basin, NE China), this study analyzed 16 thermal water samples (1900–3000 m depth) and 3 shallow groundwater samples using hydrochemical indices, water isotopes, and statistical methods (Pearson Correlation and Principle Component Analysis). Results show that the thermal water originates from precipitation and exhibits an “oxygen shift” indicating a long-time water–rock interaction under low to medium reservoir temperature. The thermal water is alkaline with a high TDS and dominated by Na⁺, Cl⁻, and HCO₃⁻, and its hydrochemical facies changes from HCO₃·Cl–Na to Cl·HCO₃–Na and Cl–Na along the groundwater flow path. Leaching of halite, silicates, and carbonates is the primary process controlling solute accumulation. The geothermal reservoir is in a relatively closed, strong reducing environment, and thermal water reached water–rock equilibrium with respect to Na-, K-, Ca-, and Mg-alumino silicates. Principle Component Analysis identifies three key controlling factors, including mineral leaching, organic matter degradation, and sulfate reduction/mineral precipitation. This study establishes a hydrogeochemical baseline for the initial exploitation stage, providing a scientific basis for predicting long-term water quality changes and formulating differentiated sustainable development strategies for the Lindian geothermal field. Full article

Shale gas extraction is underway in the Karoo Basin. Previous oil and gas explorers abandoned several wells, and the abandonment statuses of these wells are unknown. Critically, improperly abandoned wells can provide a pathway for the leakage of stray gas into shallow aquifers and degrade water quality. To understand the abandonment integrity risk posed by these wells, a qualitative risk model was developed to assess the likelihood of well-barrier failure leading to a potential leak. The potential leak paths identified include zones with cement losses during grouting, casing corrosion, cement channels, failure to case and cement risk zones, uncased and uncemented sources, uncemented annuli, and unplugged wells. To confirm whether these wells are leaking, geochemical tracing of stray gas was integrated. Eleven of the fifty samples collected had dissolved hydrocarbon gas concentrations that were high enough to use isotopic analysis to determine the source. The results revealed microbial gas via fermentation and carbon dioxide reduction, thermogenic gas, and geothermal gas, as evidenced by larger δ¹³C₁ values and isotopic reversals associated with dolerite intrusions. The thermogenic-type gas detected in legacy abandoned wells and <1 km water boreholes adjacent to these wells serves as evidence that the downhole plugs did not maintain their integrity or were improperly plugged, whereas the thermogenic gas detected in >1 km water boreholes indicates leakage contamination due to natural fracture pathways. The presence of thermogenic gas in legacy wells and in groundwater boreholes <1 km from legacy wells implies that shale gas extraction using hydraulic fracturing cannot be supported in these situations. However, using safety buffer zones greater than 1 km from the legacy wells for shale gas drilling could be supported. Full article

The interaction between organic and inorganic nutrients, bacterial communities, and soil fertility has been well documented over time. Conventional agricultural systems heavily utilize both inorganic and organic fertilizers, each exerting distinct effects on soil microbial dynamics and plant growth. The objective of our experiments was to identify the most effective fertilization strategy for improving the biological quality of a microbiologically impoverished and low-productivity soil. To this end, four fertilization strategies were evaluated: (i) organic fertilizers characterized by a high content of organic carbon (Fertil 4-5-7—variant 1); (ii) organic fertilizers with 12% organic nitrogen from proteins (Bio Ostara N—variant 2) (iii) combined inorganic–organic fertilizers (P35 Bio—variant 3) and (iv) mineral (inorganic) fertilizers (BioAktiv—variant V4). This study aimed to assess the short-term effects of fertilizers with varying chemical compositions on the density of cultivable heterotrophic bacteria and their associated dehydrogenase (DH) activity in a petrocalcic chernozem soil containing pedogenic carbonates. Soil sampling was conducted according to a randomized block design, comprising four replicates per treatment (control plus four fertilizer types). The enumeration of cultivable bacteria was performed using Nutrient Agar and A2R Agar media, whereas dehydrogenase activity (DHA) was quantified based on the reduction of 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) to 1,3,5-triphenyl-tetrazolium formazan (TPF) by bacterial dehydrogenase enzymes. Marked differences were observed in both parameters between the plots amended with inorganic fertilizers and those treated with organic fertilizers, as well as among the organic fertilizer treatments of varying composition. The most pronounced increases in both bacterial density and dehydrogenase activity (DHA) were recorded in the plots receiving the fertilizer with a high organic nitrogen content. In this treatment, the maximum bacterial population density reached 6.25 log₁₀ CFU g⁻¹ dry soil after approximately two months (May), followed by a significant decline starting in July. In contrast, DHA exhibited a more rapid response, reaching its peak in April (42.75 µg TPF g⁻¹ soil), indicating an earlier DHA activation of microbial metabolism. This temporal lag between the two parameters suggests that enzymatic activity responded more swiftly to the nutrient inputs than did microbial biomass proliferation. For the other two organic fertilizer variants, bacterial population dynamics were broadly similar, with peak densities recorded in June, ranging from 5.98 log₁₀ CFU g⁻¹ soil (V3) to 6.03 log₁₀ CFU g⁻¹ soil (V1). A comparable trend was observed in DHA: in V3, maximum DHA was attained in June (30 µg TPF g⁻¹ soil), after which it remained relatively stable, whereas in V1, it peaked in June (24.05 µg TPF g⁻¹ soil) and subsequently declined slightly toward the end of the experimental period. Overall, the temporal dynamics of bacterial density and DHA demonstrated a strong dependence on the quality and biodegradability of the organic matter supplied by each fertilizer. Both parameters were consistently lower under inorganic fertilization compared with organic treatments, suggesting that the observed increases in microbial density and activity were primarily mediated by the enhanced availability of organic substrates. The relationship between the density of culturable heterotrophic bacteria and dehydrogenase (DH) activity was strongly positive (r = 0.79), indicating a close functional linkage between bacterial density and oxidative enzyme activity. This connection suggests that the culturable fraction of the heterotrophic microbial community plays a key role in the early stages of organic matter mineralization derived from the applied fertilizers, particularly in the decomposition of easily degradable substrates. Full article

Machining of medium-carbon steels, such as AISI 1050, poses a significant challenge in terms of achieving stable cutting conditions, controlled chip evacuation and high surface integrity, in particular when full-face milling is performed under elevated material removal rates. The tool surface engineering approach, particularly laser-induced micro-texturing, comprises a promising route toward modifying the tribological conditions at the tool–chip interface, thus affecting friction, heat generation, chip formation and the resultant surface finish. This study investigates the combined effects of cutting speed, axial depth of cut and tool micro-texture orientation (parallel versus orthogonal to the chip flow direction) on machining performance under wet conditions. In addition to the experimental analysis of cutting forces, chip morphology and surface roughness, this work integrates a full factorial Design of Experiments, regression modeling, and ANOVA to quantify the statistical significance of each factor and to identify dominant interactions. The regression models show strong predictive capability across all measured responses, while the ANOVA confirms the axial depth of cut and tool texture orientation as the most influential parameters. Multi-objective optimization by Pareto analysis further underlines the superiority of orthogonal micro-texturing, which consistently reduces the cutting forces and improves surface quality while promoting controlled chip segmentation. The results provide quantitative and statistically validated evidence of the enhancement of lubrication effectiveness, reduction in interface friction, and stabilization in chip formation provided by the micro-textured tools. Overall, the findings contribute to the development of data-driven machining strategies and surface-engineered cutting tools in view of improved productivity, energy efficiency and surface integrity in advanced manufacturing applications. Full article

High and variable moisture in wood logs limits their use in continuous carbonization reactors. Artificial drying emerges as a solution to homogenize the moisture of the raw material, optimizing the process, increasing yield, and improving the quality of charcoal. This study aimed to develop an experimental fixed-bed drying system for logs, evaluating the effects of cutting layout (40 cm, 20 cm, and split), diameter class (>12 cm, 12.1–14 cm, 14.1–16 cm, and 16.1–18 cm), and residence time (30, 60, and 90 min) at 300 °C. Split logs showed higher heating and drying rates, positively impacting efficiency. However, split and 20 cm logs subjected to 90 min of drying underwent combustion, indicating operational limits for these layouts under the tested conditions. The heartwood and sapwood regions of split logs heated more rapidly, resulting in higher drying rates and moisture loss, directly affecting drying efficiency. Split logs dried for 60 min showed the best drying efficiency and greatest moisture reduction, making this the most recommended treatment. This study not only demonstrates the technical feasibility of artificial drying of logs for continuous carbonization but also establishes fundamental guidelines for the development of more efficient, safe and sustainable industrial technologies in the charcoal production sector. Full article

Air pollutants and greenhouse gases share common sources, primarily originating from human activities such as energy utilization, thus presenting significant potential for synergistic control. Isolated consideration of solutions for either pollution mitigation or carbon reduction increases the unit cost of environmental governance and leads to inconsistencies and overlapping effects in policy measures. This study takes Chengdu, a low-carbon pilot city in China, as a case study. Based on clarifying the characteristics of regional air pollutant emissions and carbon emissions from energy consumption, it empirically investigates the synergistic variation in carbon emissions from diverse socioeconomic industries and multiple air pollutant emissions. The empirical results reveal the following: (1) during the research period, Chengdu’s air quality excellence rate demonstrated continuous improvement. Meanwhile, the carbon emissions from energy consumption exhibited a three-phase developmental pattern. The driving forces of growth had shifted from traditional high-energy-consuming industries to advanced manufacturing, urban basic energy demands, and energy extraction industries serving national strategies. (2) The synergistic reduction in carbon emissions with PM₁₀ and PM_2.5 reached relatively high levels from 2016 to 2019, followed by fluctuations due to the impact of the COVID-19 pandemic. The synergistic reduction between carbon emissions and SO₂ exhibited considerable volatility. The electrification trend in transportation significantly promoted the synergistic reduction in carbon emissions and NO₂ emissions. Due to the fact that O₃ is a secondary pollutant with complex sources, achieving synergistic governance with carbon emissions proved more challenging. As a result of technological limitations, the synergistic reduction in carbon emissions and CO gradually exhibited a trend of diminishing marginal effects. The synergistic reduction effects between industry-specific carbon emissions and overall air pollutant emissions can be divided into five categories: sustained high-efficiency, generally stable, fluctuating, sudden-decline, and persistently low. Full article

The aim of this study was to confirm the suitability of game meat as a sustainable substitute for farmed meat for use as a raw material in the production of dried meat products. Red deer and wild boar meat were selected for the study, and a hybrid drying method was employed, i.e., hot air drying (HAD) assisted by microwave–vacuum drying (MVD). The selection of the research material was guided by the assumed low carbon footprint of game meat (as there are no precise LCA (life cycle assessment) data), while the selection of processing methods was guided by the possibility of obtaining high-quality products with reduced energy consumption. All these aspects were intended to support sustainability in the dried meat products industry. The dried game meat obtained in this study is microbiologically stable (water activity 0.62–0.68, moisture content approx. 10% w.b.) and characterized by high quality, confirmed by high sensory quality index scores (SQI > 4.5 on a 5-point scale). The process parameter optimization of the applied hybrid three-stage drying method (HAD-MVD-HAD) also allowed for a reduction in energy consumption of almost 40% compared to the most commonly used single-stage HAD method. These achievements confirm the great potential of using game meat in the food industry, which in turn may contribute to more sustainable production practices. Full article

The reproducibility of oxygen reduction reaction (ORR) activity assessment for platinum-based electrocatalysts using the rotating disk electrode (RDE) method is critically dependent on the quality of the fabricated catalytic layer. This work presents a comprehensive study on optimizing catalytic ink formulation—specifically the water-to-isopropanol (H₂O:IPA) solvent ratio and the ionomer-to-carbon (I/C) ratio—to achieve a homogeneous catalytic layer and ensure high data reproducibility for monometallic Pt/C and bimetallic PtCu/C catalysts. A key aspect of this research is the implementation of a simple and effective visual inspection method using a benchtop digital microscope to rapidly assess catalytic layer quality, which was shown to correlate directly with electrochemical performance. The optimal ink composition was found to be catalyst-specific. For Pt/C, the highest mass activity of 353 A/g~Pt~ was achieved with a solvent ratio of 1:3 (H₂O:IPA) and an I/C ratio of 0.3. For PtCu/C, the best performance was obtained with the same solvent ratio (1:3) but a higher I/C ratio of 0.4, yielding a mass activity of 491 A/g~Pt~. It was demonstrated that ink compositions leading to layer inhomogeneities, such as aggregates and “coffee-ring” effects, significantly impair mass transport and lead to underestimated ORR activity. The study underscores the absence of a universal ink recipe and establishes that the optimization of ink parameters for each specific catalyst is essential for obtaining reliable and reproducible electrochemical data. Full article

The effectiveness of transit-oriented development (TOD) in achieving emission reductions and energy savings is highly influenced by policy frameworks, the accessibility of sustainable transport systems, and the degree of land use integration. This study investigated the implementation of TOD in Dukuh Atas along the Sudirman–Thamrin corridor in Jakarta to assess its role in promoting energy efficiency and lowering emissions. The analysis incorporated carbon emission calculations, annualized traffic volumes, and emissions data, alongside land use metrics such as the floor area ratio (FAR), job-to-housing ratio, and point-of-interest (POI) density. The findings indicate that while TOD implementation in the corridor is still evolving, there were positive outcomes in several key areas. Energy efficiency measures have been partially realized through the operation of electric buses in the bus rapid transit (BRT) system, electrified rail modes, such as commuter lines, mass rapid transit (MRT), and light rail transit (LRT), and improved pedestrian infrastructure, as reflected in a favorable Pedestrian Environmental Quality Index (PEQI). Public transport ridership has significantly increased, contributing to a measurable reduction in emissions from private vehicle use. The land use analysis showed that medium- to high-density housing dominated (78.94% FAR), with a job-to-housing ratio of approximately 1:2. This study also found that the emission estimates were moderately sensitive to changes in both emission factors (EFs) and vehicle kilometers traveled (VKT). Overall, the results suggest that TOD can effectively contribute to energy savings and emission reductions by enhancing public transport usage and reducing dependence on motorcycles. Moreover, the efficacy of modal shifting in the Global South is significantly influenced by population mobility characteristics, which are intricately linked to socio-cultural factors, alongside government initiatives to improve the quality of mass public transportation systems (e.g., integration, availability, service coverage, affordable fares, and inclusive design). Full article

As a new engine for promoting the high-quality development of China’s foreign trade, digital trade provides new opportunities for enterprises’ low-carbon transition. Based on samples of export industrial enterprises listed in China from 2010 to 2023, this paper uses the digital trade policy represented by the cross-border e-commerce (CBEC) comprehensive pilot zone as a quasi-natural experiment and employs a multi-period difference-in-differences (DID) model to empirically analyze the policy effect of digital trade development on firms’ carbon emission intensity. This research finds that (1) digital trade policies represented by the pilot policy can significantly reduce firms’ carbon emission intensity and (2) the pilot policy can achieve the emission intensity reduction effect through dual paths of “internal innovation deepening” and “external environment optimization”. The internal innovation deepening refers to the green awareness formation and green production implementation of enterprises. External environment optimization refers to financial support resources for enterprises and institutional safeguards for innovation rights of enterprises. (3) Further analysis indicates that the policy effects are more pronounced in firms with higher risk preference, with larger scale, in heavily polluting and high-tech industries, and in the central and northeastern regions. Additionally, the policy demonstrates synergistic effects with the Belt and Road Initiative and exhibits significant spatial spillover effects, benefiting neighboring non-pilot areas. Full article

Diesel-powered machinery is the primary energy source in underground mining, exposing workers to hazardous diesel exhaust emissions. This study evaluates occupational exposure to diesel particulate matter (DPM) and gaseous pollutants (NO, NO₂) at an underground mine before and after implementing Diesel Particulate Filters (DPF) and Selective Catalytic Reduction (SCR) in mining equipment. A comprehensive monitoring campaign was conducted, employing elemental carbon (EC) as a tracer for diesel particulate emissions and electrochemical sensors for gas measurements. Results show a substantial reduction in EC concentrations following the implementation of DPFs, with median EC exposure decreasing from 0.145 mg/m³ in 2021 to 0.034 mg/m³ in 2023, and the proportion of samples exceeding the occupational exposure limit (OEL) falling from 90% to 28%. Similarly, SCR implementation led to a 72% reduction in NO₂ levels and a 77.5% decrease in NO concentrations in certain equipment; however, NO levels remained persistently high near loaders, suggesting that additional mitigation measures are required. These findings underscore the efficacy of DPF and SCR technologies in improving air quality and reducing occupational exposure in underground mining environments. Nevertheless, persistent NO concentrations and maintenance-related challenges highlight the need for a holistic emission control approach, integrating ventilation improvements, expanded DPF adoption, alternative propulsion systems, and enhanced maintenance protocols. This study provides critical insights into the effectiveness of advanced emission reduction strategies and informs future regulatory compliance efforts in the mining industry. Full article

The utilization of lime kiln flue gas for producing CO₂-based fertilizer represents an emerging pathway to link industrial emission reduction with sustainable agricultural development. This review summarizes recent progress in CO₂ capture, purification, and application technologies, with a focus on their suitability for protected agriculture. It discusses the advantages of high CO₂ concentration and low-temperature tail gas, the challenges posed by impurities, and the technological routes for efficient CO₂ recycling. The review highlights that controlled CO₂ fertilization can significantly enhance crop growth and quality, while the effects of residual gases and uneven distribution require further investigation. Future research should prioritize the development of scalable, low-cost adsorbents and precision fertilization systems based on digital twin technologies to promote the integration of industrial carbon recycling and smart agriculture. Full article

The present study explores the production of metallized titanomagnetite briquettes, with a view to addressing two key issues. Firstly, it seeks to address the growing shortage of high-quality iron-bearing raw materials. Secondly, it looks at how to meet the increasingly stringent environmental constraints. The conventional blast-furnace treatment of titanomagnetite is hindered by the formation of refractory Ti-rich slags. It is hereby proposed that a single-cycle briquetting process in conjunction with a thermal reduction route should be utilized. This approach enables precise regulation of the Fe/flux ratio. Experiments were conducted on a low-grade titanomagnetite concentrate (68.5% Fe) from the Pervouralsk deposit (Russia). Cylindrical briquettes (D 15–20 mm, h 8–10 mm) were subjected to a pressure of 300 MPa during the pressing process, with the utilization of diverse binders comprising rubber cement, CaO, graphite + water, and basic oxygen-furnace (BOF) slag + sodium silicate. Following an oxidative pre-heating process at 1300 °C for two hours, followed by a gas-based reduction process at 1050 °C for three hours, with a CO/N₂ ratio of 90/10, the products demonstrated an oxidation rate of 85–95% and a cold compression strength of 16–80 MPa. The highest observed strength (80 MPa) was obtained with a binder comprising CaO·MgO·2SiO₂ (diopside/merwinite), which forms a low-viscosity melt, fills 90% of pores and crystallizes as acicular Mg-SFCA-I during cooling. Conversely, the CaO·TiO₂ and FeO·TiO₂ + Fe₃C associations yield brittle structures and a maximum strength of 16 MPa. The optimum briquette (0.55% CaO, D/H = 20/10 mm) exhibited a 95.7% metallization degree, a compressive strength of 48.9 MPa, and dimensional changes within acceptable limits, thus fulfilling the requirements for electric arc furnace feedstock. Further research is required in the form of a full Life Cycle Assessment and pilot-scale testing. However, the results obtained thus far confirm that titanomagnetite briquettes with a binder consisting of CaO, MgO and SiO₂ are a promising alternative to pellets for low-carbon steelmaking. Full article

The energy-saving performance of the building envelope, which plays a pivotal role in energy conservation and thermal insulation, has been the subject of extensive research. In the context of China’s high-quality green development, this study proposes a building energy-saving strategy based on optimal thermal comfort. It analyzes the impact of factors such as regional dwell time and PMV types on energy-saving effects, summarizes the optimal comfort parameters under the highest energy efficiency rate, and sets relevant parameters in the DeST building energy simulation software to analyze a typical public building. The analysis examined the impact of changing the heat transfer coefficients of exterior walls and windows on the annual cumulative heating and cooling loads. It established the relationship between the thermal transmittance of building envelopes and energy consumption and assessed the carbon emissions during the building’s operation and maintenance phase. The results indicate that as building envelope thermal transmittance coefficient decreases, particularly that of external windows and walls, overall cumulative heating and cooling loads decline accordingly. Notably, the reduction in external windows’ thermal transmittance coefficient has the most significant impact on total building thermal load. Furthermore, as the envelope thermal transmittance coefficient decreases, seasonal heating and cooling demands decline simultaneously, with the most substantial effect on heating load reduction during winter. Total annual building carbon emissions also decrease with the reduction in envelope thermal transmittance coefficient, particularly external wall thermal transmittance coefficient. Based on the findings of this study, the building envelope of the public building was redesigned, taking into account construction costs, the owner’s requirements, and energy efficiency alongside the reduction in carbon emissions. Comparisons of the redesigned building’s envelope thermal performance, experimental testing, and in situ measurements confirmed that it fulfilled the engineering requirements. This study also demonstrates that DeST software provides reliable technological support for low-carbon building design, retrofitting, and operation. Full article

Cashew nut shell liquid (CNSL) is a byproduct of cashew processing that has largely been overlooked as a biomass resource for biodiesel production. While some research has been conducted on CNSL in diesel engines, there remains a lack of studies on using processed CNSL with industrial waste catalysts for diesel engines. This study focuses on the performance and emissions of catalytically cracked CNSL (CC-CNSL) created with fly ash as a catalyst. Blends of 25%, 50%, 75%, and 100% CC-CNSL-diesel were used as a fuel in a single-cylinder diesel engine under different load conditions. The CC-CNSL25 blend, which contains 25% CC-CNSL, outperformed the others with a 2% increase in brake thermal efficiency. Additionally, it showed substantial reductions in emissions, i.e., 11.76% less carbon monoxide, 9.09% reduced smoke density, 8.57% lower hydrocarbon emissions, and 5.27% decreased specific fuel consumption compared to conventional diesel at full load. This research highlights fly ash-catalyzed CNSL processing as an effective method for converting agricultural waste into high-quality biodiesel. It offers a dual advantage as a sustainable fuel source while addressing waste management challenges. Full article