Search Results (2,040)

This study addresses the challenge of multi-dimensional and small gas sensor data classification using a gelatin–carbon black (CB-GE) composite film sensor, achieving 91.7% accuracy in differentiating gas types (ethanol, acetone, and air). Key techniques include Principal Component Analysis (PCA) for dimensionality reduction, the Synthetic Minority Over-sampling Technique (SMOTE) for data augmentation, and the Support Vector Machine (SVM) and K-Nearest Neighbor (KNN) algorithms for classification. PCA improved KNN and SVM classification, boosting the Area Under the Curve (AUC) scores by 15.7% and 25.2%, respectively. SMOTE increased KNN’s accuracy by 2.1%, preserving data structure better than polynomial fitting. The results demonstrate a scalable approach to enhancing classification accuracy under data constraints. This approach shows promise for expanding gas sensor applicability in fields where data limitations previously restricted reliability and effectiveness. Full article

The relationship between ports and energy markets is undergoing a transition in their functions as suppliers, consumers, and energy processors. Environmental factors increasingly force the maritime sector to reduce its carbon footprint and improve energy efficiency. Governing the maritime sector’s environmental performance requires leveling decarbonization through integration with energy supply chains and rethinking green strategies and environmental sustainability. This paper highlights that a port’s energy management system can be an example of supply–demand equalizing sustainable alternative energy sources. Such systems engage more profoundly within the energy value chain by assessing green and environmental indicators in port operations, strategies, and investments. This manuscript investigates the challenges in ports’ operations, strategies, and investments, considering their energy transition and decarbonization. Therefore, this research conducted a qualitative study on ports’ energy efficiency and greening using an in-depth interview method in three seaports in the Adriatic, Baltic, and Black Sea basins. The paper proposes a framework for analyzing green variables in the ports’ operations, strategies, and investments to improve their environmental performance. The framework examines a set of green variables, researching their cause-and-effect relationship, enabling testing and evaluation of the determined relationships, and identifying asynchrony in the balanced development of green investments and energy efficiency. Full article

The greenhouse effect, which is also promoted by naturally occurring biogas ebullition fluxes (released via bubbles), generated by the decomposition of organic matter in carbonate-enriched and black silt sediments, has been analyzed. This study is based on results obtained using passive gas collectors at different parts of eutrophic Lake Juodis, located in a temperate climate zone in the vicinity of Vilnius (Lithuania). The measured annual biogas (containing about 60% of biomethane) ebullition fluxes from carbonate-enriched sediments and black silt sediments were 16.9–23.0 L/(m²∙y) and 38.5–43.2 L/(m²∙y), respectively. This indicates that the gas fluxes from carbonate sediments were almost twice as low as those from black silt sediments. Oxygen, produced by the photosynthetic activity of green algae in the near-surface water and sediments, helps to retain carbonates in the sediments by preventing their dissolution. In turn, the calcite coating on sediment particles partially preserves organic matter from decomposition, reducing the effective thickness of the sediment layer generating biogas. The characteristic vertical distribution profile of ¹³⁷Cs activity, with sharp peaks in sediments, suggests that generated biogas bubbles move to the surface of the sediments forming vertical channels by pushing sediment particles asides without noticeably mixing them vertically. This examination showed that factors such as abundance of carbonates in the sediments may result in a significant reduction in biogas generation and emissions from the lake sediments. Full article

Pt on carbon black (Pt/C) has been widely used as a catalyst for both ORR and hydrogen oxidation reaction (HOR), but its stability is compromised due to carbon corrosion and catalyst poisoning, leading to low Pt utilization. To address this issue, this study suggests replacing carbon black with graphene in the catalyst layer. The importance of this work lies in the detailed examination of novel electrocatalysts with high electrocatalytic activity for large-scale power generation. In this paper, we discuss the use of regulatory techniques like structure tuning and composition optimization to construct nanocatalysts impregnated with noble and non-noble metals on graphene supports. Finally, it highlights the limitations and advantages of these nanocatalysts along with some future perspectives. Our objective is that this summary will help in the research and rational design of graphene-based nanostructures for efficient ORR electrocatalysis. The results of this study showed that the performances of graphene-based catalysts show high electrochemical active surface areas for Pt-Fe/GNPs and Pt-Ni/GNPs catalysts (132 and 136 m² g⁻¹, respectively) at 100 operating cycles. Also, high current densities and power densities were observed for Pt₃-Ni/G and Pt-Co/G catalysts used at the cathode. The values for current density were 1.590 and 1.779 A cm⁻², respectively, while the corresponding values for power density were 0.57 and 0.785 W cm⁻². Full article

Disentangling the responses of total soil organic carbon (SOC), organic carbon fractions and soil aggregate stability to various vegetation types is essential for better understanding the carbon cycling process in terrestrial ecosystems, maintaining soil quality and mitigating global warming. To study the effects of vegetation types on soil aggregates in a specific area, the desert riverbanks of arid regions were studied. We set up experiments using three typical vegetation types in the arid zone of the Tarim River Basin (TRB), including Forestland, Shrubland, and Grassland. The total SOC content in the bulk soil and different soil aggregates was determined by oxidation with K₂Cr₂O₇ and H₂SO₄, and three carbon fractions (F1, very labile; F2, inert; F3, oxidizable resistant) were classified according to the degree of oxidation using the modified Walkley-Black method. The total SOC and three carbon fractions in the soil were significantly greater in the Forestland than in the other vegetation types, and the effect was more pronounced in macro-aggregate (MA) than in the other aggregates. In the bulk soil and soil aggregates, the percentages of F1, F2 and F3 in the total SOC with mean values of 0.36%, 0.28% and 0.36%, respectively, at soil depths of 0–20 cm, indicated that stabilizing carbon is the major carbon fraction of the SOC. The stability of the SOC in the aggregates across each vegetation type was greater in the lower layer (10–20 cm) than in the topsoil layer (0–10 cm). The SOC stability and MA content were positively related to the SOC in the soil aggregates and its F2 and F3 fractions (p < 0.05). In summary, the Forestland significantly increased the SOC content and enhanced SOC stability. Conservation measures for poplar forests in vulnerable arid zones can sustainably accumulate SOC sequestration. Full article

This study evaluated the capability of coal fly ash (untreated and physicochemically modified) when utilised as a filler in cis-1,4-polyisoprene rubber. Physicochemical modification of the ash was achieved using two techniques: (1) ammonium sulphate roasting followed by controlled aqueous dissolution and (2) sulphuric acid leaching. In addition, the effectiveness of a silane-coupling agent (Si-69) in enhancing the compatibility of untreated and physically modified ash samples with natural rubber was investigated. The ammonium sulphate roasting route increased the surface area and roughness and decreased the particle–particle agglomeration of the fly ash sample. Sulphuric acid treatment decreased the particle–particle agglomeration. However, no increase in surface roughness was observed. The untreated fly ash samples were not significantly reinforcing, and the properties they imparted were inferior to the least reinforcing carbon black. Silane treatment resulted in improved dispersion and wetting of the fly ash in the rubber matrix, leading to improved reinforcement compared to neat rubber. In situ addition of the silane during preparation of the vulcanisates led to composites with better mechanical properties than the composites containing silane-pre-treated fly ash. Composites filled with ammonium sulphate-roasted-and-leached ash performed better than the composites filled with untreated ash and sulfuric acid-leached ash. These findings suggest that modified fly ash holds promise as an effective filler for rubber materials, offering potential environmental and economic benefits by repurposing coal combustion by-products. Full article

Moulds for aeronautical applications must fulfil highly demanding requirements, including the geometrical tolerances before and after curing cycles at high temperatures and pressures. The growing availability of thermoplastic materials printed by material extrusion systems requires research to verify the geometrical accuracy after three-dimensional printing processes to assess whether the part can meet the required geometry through milling processes. In this sense, the application of automated techniques to assess quick and reliable measurements is an open point under this promising technology. This work investigates the integration of a 3D vision system using a structured-light 3D scanner, placed onto an industrial robot in an eye-in-hand configuration and synchronized by a computer. The complete system validates an in-house algorithm, which inspects the whole reconstructed part, acquiring several views from different poses, and makes the alignment with the theoretical model of the geometry of big parts manufactured by 3D printing. Moreover, the automation of the validation process for the manufactured parts using contactless detection of the offset-printed material can be used to define milling strategies to achieve the geometric qualifications. The algorithm was tested using several parts printed by the material extrusion of a thermoplastic material based on black polyamide 6 reinforced with short carbon fibres. The complete inspection process was performed in 38 s in the three studied cases. The results assure that more than 95.50% of the evaluated points of each reconstructed point cloud differed by more than one millimetre from the theoretical model. Full article

By reflecting on the history and environmental impact of conventional biorefining, such as kraft pulping, we aim to explore important questions about how natural polymers can be more sustainably sourced to develop bio-products and reduce reliance on plastics. Since the Industrial Revolution, chemical pulping processes have enabled the mass production of cellulosic products from woody biomass. Kraft pulping, which dominates within modern pulp and paper mills, has significantly contributed to environmental pollution and carbon emissions due to sulfurous byproducts and its high water and energy consumption. While chemical pulping technologies have advanced over time, with improvements aimed at enhancing sustainability and economic feasibility, conventional biorefineries still face challenges related to biomass conversion efficiency and environmental impact. For example, efforts to fully utilize wood resources, such as isolating lignin from black liquor, have made limited progress. This perspective provides a thoughtful examination of the growth of chemical pulping, particularly the kraft process, in the production of consumer goods and its environmental consequences. It also presents key insights into the bottlenecks in developing truly sustainable biomass conversion technologies and explores potential alternatives to traditional chemical pulping. Full article

Black carbon, a short-lived climate forcer, has the dual impact of intensifying global warming and polluting the atmosphere. The further opening of Arctic shipping routes has resulted in a severe issue of black carbon emissions in this fragile region. The use of fuel, especially heavy fuel oil, in international shipping has generated enormous black carbon emissions, posing a serious threat to the climate in the Arctic and beyond. As the international community continues to pay attention to air pollution control and greenhouse gas emissions reduction, the need for effective global governance of black carbon emissions from Arctic shipping has become increasingly evident. This issue has emerged as a critical part of the broader effort to address ocean and climate governance through the lens of international law. Despite the efforts made by both the International Maritime Organization (IMO) and the Arctic Council (AC) to reduce black carbon emissions, the current international legal framework remains fragmented, with weak enforcement mechanisms and limited capacity for coordinated governance. The findings of this research underscore the importance of strengthening international legal instruments aimed at reducing black carbon emissions from Arctic shipping. In particular, there is a pressing need for the development of a dedicated international treaty with enhanced binding force to mitigate the ecological degradation in the Arctic, address global warming, and realize sustainable development goals. Full article

This work presents the fabrication of a coaxial fiber triboelectric sensor (CFTES) designed for efficient energy harvesting and gesture detection in wearable electronics. The CFTES was fabricated using a facile one-step wet-spinning approach, with PVDF-HFP/CNTs/Carbon black as the conductive electrode and PVDF-HFP/MoS₂ as the triboelectric layer. The incorporation of 1T phase MoS₂ into the PVDF-HFP matrix significantly improves the sensor’s output owing to its electron capture capabilities. The sensor’s performance was carefully optimized by varying the weight percentage of MoS₂, the thickness of the fiber core, and the CNT ratio. The optimized CFTES, with a core thickness of 156 µm and 0.6 wt% MoS₂, achieved a stable output voltage of ~8.2 V at a frequency of 4 Hz and 10 N applied force, exhibiting remarkable robustness over 3600 s. Furthermore, the CFTES effectively detects human finger gestures, with machine learning algorithms further enhancing its accuracy. This innovative sensor offers a sustainable solution for energy transformation and has promising applications in smart portable power sources and wearable electronic devices. Full article

Black Soldier Fly (Hermetia illucens) is well-known for having a high protein and lipid content during its larval stage and is cultivated for animal feed. Rearing Black Soldier Fly larvae (BSFL) produces byproducts known as frass and larval sheddings in large volumes with limited applications. Therefore, there is a need to identify viable sustainable management strategies to prevent potential environmental issues associated with their accumulation. Accordingly, the purpose of this study was to evaluate BSFL frass and larval sheddings as viable ingredients in composts that utilize additional nitrogen feedstocks. Four experimental compost piles (22.7 m³) with different ratios of BSFL frass and sheddings were developed based on previous research; two piles included 25% frass, whereas the other two included 30% frass. Across these piles, the inclusion of wood chips, food waste, and livestock manure varied to determine the best proportions for compost. The compost piles were maintained for five months, including a curing phase. After curing, samples from each pile were collected to analyze their pH, macro- and micro-nutrients, particle size, stability, and maturity. The findings indicated that the pH levels (7.1–8.1) and carbon-to-nitrogen ratios (10.40–13.20) were within the optimal ranges for all piles. The phosphorus levels (0.75–1.30%) of each pile exceeded typical ranges, likely due to the high phosphorus content of the frass itself. The moisture content varied widely (24.5–51.7%), with some piles falling below optimal levels. Stability and maturity tests yielded mixed results, with some piles demonstrating continued decomposition activity. Overall, the findings indicated that inclusion rates of 25–30% of BSFL frass and sheddings produced compost with generally favorable characteristics when high nitrogen feedstocks were also incorporated into the compost piles. These findings align with those from previous research and highlight both the potential and challenges of incorporating BSFL frass into compost production. Full article

Conservation tillage is a practice adopted worldwide to prevent soil degradation. Although there have been many studies on the impact of conservation tillage on soil quality, most studies on cultivated land in the black soil region of Northeast China are based on the physical and chemical indicators of soil. In addition, the experiment time is generally short, so there is a lack of information about long-term conservation tillage from the perspective of the physical, chemical, and biological integration of soil. A comparative analysis of the physical, chemical, and biological characteristics of soil was conducted under no-till (NT) with straw mulching and conventional tillage (CT) treatments after 19 years of field experiments. By using membership functions to normalize and render all the indicators dimensionless, and calculating the weight of each indicator through principal component analysis, the comprehensive index of soil quality can be calculated as a weighted summation. The results indicate that NT had no significant effect on soil bulk density at a soil depth of 0–20 cm. NT increased the field water-holding capacity of the 0–5 cm layer, reduced the total porosity of the 5–10 cm soil layer, and decreased the non-capillary porosity of the 0–20 cm soil layer. Compared to CT, NT significantly increased the organic carbon content of the soil in the 0–5 cm layer, comprehensively improved the total nutrient content of the soil, and significantly increased the contents of ammonium nitrogen, nitrate-nitrogen, and available phosphorus in the soil. It also significantly improved the total phosphorus content in the 5–20 cm soil layer. NT improved the microbial carbon and nitrogen content of the soil, significantly enhanced the microbial nitrogen content in the 0–5 and 5–10 cm soil layers, and reduced the bacterial species diversity in the 5–10 cm soil layer. However, the soil enzyme activities showed no significant differences between different treatments. Under the NT treatment, the evaluation of soil quality indicators, such as mean weight diameter, field water-holding capacity, non-capillary porosity, microbial biomass nitrogen, total nutrients, and available nutrients, was relatively successful. Based on the weight calculation, the organic carbon, catalase activity, fungal richness, and bacterial diversity indicators are the most important of the 22 soil quality indicators. In terms of the comprehensive index of soil fertility quality, NT increased the soil quality comprehensive index by 34.2% compared to CT. Long-term conservation tillage improved the physical, chemical, and biological properties of the soil, which significantly enhanced the quality of the black soil. Full article

This study presents data on the use of shungite ore (the Bakyrchik deposit, Kazakhstan) and its concentrate as fillers in elastomer composites based on nitrile butadiene rubber. In addition to carbon, these shungite materials contain oxides of Si, Fe, K, Ca, Ti, Mn, and Al. The shungite concentrate was obtained through a flotation process involving five stages. The chemical composition analysis of these natural fillers revealed that during flotation, the carbon content increased 3.5 times (from 11.0 wt% to 39.0 wt%), while the silicon oxide content decreased threefold (from 49.4 wt% to 13.6 wt%). The contents of oxides of K, Ca, Ti, Mn, and Al decreased by less than 1%, and iron oxide content increased by 40% (from 6.7 wt% to 9.4 wt%). The study explored the impact of partial or full replacement of carbon black (CB) of P 324 grade with the shungite ore (ShO) and the shungite concentrate (ShC) on the vulcanization process and the physical–mechanical properties of the rubber. It was found that replacing CB with ShO and ShC reduces Mooney viscosity ML (1 + 4) 100 °C of the rubber compounds by up to 29% compared to the standard CB-filled sample. The use of the shungite fillers also increased scorch time (t_s) by up to 36% and cure time (t₉₀) by up to 35%. The carbon content in the shungite fillers had little influence on these parameters. Furthermore, it was demonstrated that replacing 5–10 wt% of CB with ShO or ShC improves the tensile strength of the rubber. The results of the flotation enrichment process enable the assessment of how these shungite fillers affect the properties of the composites for producing rubbers with specific characteristics. It was also found that substituting CB with ShO or ShC does not significantly affect the rubber’s resistance to standard oil-based media. The findings indicate that Kazakhstan’s shungite materials can be used as fillers in rubber to partially replace CB. Full article

The influence of molecular structure (acrylonitrile content) and formulation (carbon black and plasticizer dosage) on the rheological and mechanical properties of HNBR composites was systematically studied, with further discussion on ozone resistance and swelling behavior in transformer oil. The results demonstrated that the curing characteristics and rheological behavior of HNBR composites are closely linked to acrylonitrile content, carbon black, and plasticizer levels. Plasticizers significantly reduced the degree of crosslinking and the Payne effect, while fillers had the opposite impact. Fillers increased the modulus at 100% and 200%, reducing elongation at break, whereas plasticizers enhanced elongation at break while lowering the modulus. The effects of fillers and plasticizers on tensile strength were relatively minor. Both exhibited different influences on mechanical properties at various aging temperatures. Compression set testing revealed that under a 125 °C hot air environment, the compression set was less than 30%, while at −30 °C in cold air, it exceeded 60%. In a 125 °C hot transformer oil environment, the compression set ranged between 30% and 60%. Oil resistance tests indicated that HNBR composites with higher acrylonitrile content showed lower mass change rates in transformer oil, with further reduction achieved by increasing the plasticizer or filler content. Due to their excellent performance and resistance to ozone cracking, HNBR composites have significant potential for applications in high-altitude power grids and military-grade rubber sealing products. Full article

This study investigated the influence of preformed composition and pore size on the microstructure and properties of SiC_f/SiC composites fabricated via reactive melt infiltration (RMI). The process began with the impregnation of SiC fiber cloth with phenolic resin, followed by lamination and pyrolysis. Subsequent steps included further impregnations with phenolic resin, SiC slurry, and carbon black slurry, each followed by additional pyrolysis. This process resulted in three types of preforms, designated as PP, PS, and PC. These preforms exhibited a multimodal distribution of pore size, with peak pore diameters around 5 μm for PP, ranging from 200 nm to 4 μm for PS, and approximately 150 nm for PC. The preforms were then subjected to molten silicon infiltration at 1600 °C under vacuum for 1 h to create SiC_f/SiC composites. The PP preform contained only pyrolytic carbon, leading to a composite with high closed porosity and unreacted carbon, resulting in poor mechanical properties. The PS preform, which was impregnated with SiC particles, displayed an optimized pore size distribution but retained significant amounts of residual silicon and carbon in the final composite. In contrast, the PC preform featured both an ideal pore size distribution and an adequate amount of carbon, achieving high density and low porosity with reduced residual phases in the final composite. This optimization led to a flexural strength of 152.4 ± 15.4 MPa, an elastic modulus of about 181.1 ± 0.1 GPa, and a thermal conductivity of 27.7 W/mK in the SiC_f/SiC composites product. These findings underscore the importance of preform optimization in enhancing the performance of SiC_f/SiC composites, potentially paving the way for more reliable nuclear fuel cladding solutions. Full article