Search Results (171)

The paper presents the application of high-speed flame imaging combined with convolutional neural networks (CNNs) for determining different states of biomass–coal co-combustion in terms of thermal power and excess air coefficient. The experimental setup and methodology used in a laboratory-scale co-combustion system are described, highlighting tests conducted across nine defined operational variants. The performance of several state-of-the-art CNN architectures was examined, focusing particularly on those achieving the highest classification metrics and exploring the dependence of input image resolution and applying a transfer learning paradigm. By benchmarking various CNNs on a large, diverse image dataset without preprocessing, the research advances intelligent, automated control systems for improved stability, efficiency, and emissions control, bridging advanced visual diagnostics with real-time industrial applications. The summary includes recommendations and potential directions for further research related to the use of image data and machine learning techniques in industry. Full article

Excessive exhaust backpressure (EBP) in modern diesel engines disrupts gas exchange, increases residual gas fraction (RGF), and reduces combustion efficiency. Traditional experimental approaches, including simulations and bench testing, are often time-consuming and costly, which has driven growing interest in artificial neural networks (ANNs) for accurately modelling complex engine behavior. This research introduces an ANN model designed to predict the impact of EBP on the performance and emissions of a diesel engine across varying compression ratio (CR) of 12, 14, 16, and 18 and engine load (25%, 50%, 75%, and 100%) conditions. The ANN model was developed and optimised using genetic algorithms (GA) and particle swarm optimisation (PSO). It was then trained using data from an experimentally validated one-dimensional computational fluid dynamics (1D-CFD) model developed through GT-Power GT-ISE v2024, simulating engine responses under variation CR, load, and EBP conditions. The optimised ANN architecture, featuring an optimal (3-14-10) configuration, was trained using the Levenberg–Marquardt back propagation algorithm. The performance of the model was assessed using statistical criteria, including the coefficient of determination (R²), root mean square error (RMSE), and k-fold cross-validation, by comparing its predictions with both experimental and simulated data. Results indicate that the optimised ANN model outperformed the baseline ANN and other machine learning (ML) models, attaining an R² of 0.991 and an RMSE of 0.011. It reliably predicts engine performance and emissions under varying EBP conditions while offering insights for engine control, optimisation, diagnostics, and thermodynamic mechanisms. The overall prediction error ranged from 1.911% to 2.972%, confirming the model’s robustness in capturing performance and emission outcomes. Full article

Ammonia bunkering is becoming increasingly important in the maritime industry as ammonia is recognized as a viable alternative fuel for reducing carbon emissions in shipping. Bunkering by tank truck plays a crucial role in the early stages of ammonia-fueled ship development. It involves the efficient transportation of ammonia from production facilities to bunkering stations, offering flexibility in refueling vessels at ports, including those lacking extensive infrastructures like pipelines or large storage tanks. However, the safety and regulations surrounding ammonia use in bunkering are paramount to its adoption. This study focuses on analyzing the effectiveness of safeguards designed to reduce the frequency of ammonia releases and mitigate potential leak damage during bunkering operations. We examine how safeguards, such as breakaway couplings and dry disconnect couplings (DDC), can reduce leak occurrences, while excess flow valves (EFVs) and automatic emergency shut-off valves (ESVs) can limit the consequences of such incidents. If the breakaway coupling and DDC are implemented as safeguards in the flexible hose, and maintenance is performed in accordance with ANSI/CGA G-2.1, the probability of hose failure per bunkering operation will be reduced from approximately 10⁻⁵ to 10⁻⁷. Under the worst weather conditions during the day, the probit value (Pr) depends on both the amount of ammonia released and the distance from the release point, with the distance having a greater effect on fatality than the amount of ammonia. The individual risk is analyzed to determine whether the bunkering process using tank trucks is acceptable. The analysis concludes that, with these safeguards in place, the individual risk at a location 20 m from the bunker site can be reduced to the lower limit of the As Low As Reasonably Practicable (ALARP) zone, ensuring a safe and acceptable level of risk for ammonia bunkering operations. The safety integrity level (SIL) of the automatic ESV should be at least 2 or higher, and it should be activated within a few seconds after a gas leak begins. Full article

The use of light at night may contribute to the inappropriate or excessive use or presence of artificial light known as light pollution. Light pollution wastes huge amounts of electricity and money and contributes to global warming as well as having significant impacts on wildlife. There is a recognition that many of the issues that drive light pollution should be engaged by local, often pragmatic, governments. Lighting policies need to manage light pollution while also providing the intended services. To achieve this, local governments could develop policies and interventions in terms of three main considerations: functionality, technology, and the behaviours that comprise social usage. To determine to what extent this is being done, the lighting policies of the local governments of greater Melbourne are investigated, along with the related Australian Standards associated with lighting. Very few of the local governments in greater Melbourne had an explicit policy addressing light pollution and none of them considered the likelihood of behavioural issues such as rebounds in energy use. The results of this study suggest that policies that reduce light pollution, with controls to avoid behavioural complications such as rebound effects, should reduce costs for local governments and reduce greenhouse gas emissions. Full article

Arizona has committed to reducing emissions by 50–52% by 2030 and achieving net-zero emissions by 2050, requiring major changes to its electricity infrastructure. This study develops a MATLAB model with hourly electricity load and solar insolation data to determine the solar PV and energy storage infrastructure required to replace all utility-scale non-renewable generation. Whereas PV tilt angle is typically optimized to maximize solar capture, this study instead links tilt and tracking configuration to land use, storage requirements, and total system cost to identify the optimal configuration. Results show that a 76 GW_DC 0° fixed-tilt system requires ~0.15% (438 km²) of Arizona’s land to achieve a carbon-neutral grid. Increasing tilt decreases the land required to 287 km² at 54° for fixed-tilt systems and 221 km² at 65° for single-axis tracking systems. A minimum of 320 GWh of annual energy storage is required based on TMY solar insolation data, which increases to 430 GWh for the 2022 time synchronized analysis. A 0° fixed-tilt angle system with energy storage is the cheapest configuration at USD 218 billion. At this tilt, PV generation produces ~80,000 GWh of excess electricity annually, 47% of which could achieve 80% decarbonization across all sectors of the economy. Full article

In intensive agriculture, the excessive application of chemical fertilizers leads to approximately 50% nitrogen loss, which exacerbates water pollution and the greenhouse effect. Meanwhile, nitrogen and phosphorus emissions from livestock manure have far exceeded those from chemical fertilizers, becoming the primary source of agricultural non-point-source pollution. This study aims to clarify the comprehensive effects of combining manure with urea application and precision irrigation on the soil environment, lettuce growth, and quality, and to determine the optimal water and fertilizer management strategy. The results indicate that combining manure with urea application and precision irrigation can effectively mitigate non-point-source pollution, enhance soil nutrients, promote lettuce growth, and improve quality. When the irrigation volume reaches 75–78% of field capacity and the ratio of manure to urea nitrogen ranges from 7:3 to 1:1, key indicators for soil health, lettuce growth, and quality can exceed 90% of their respective maximum levels. This study provides a scientific basis and practical guidance for the resource utilization of manure and precise water–fertilizer management in intensive lettuce production. Full article

In this study, the objective is to assess the impacts of NH₃ emissions from mink farming on human health and nature, which are sensitive to atmospheric nitrogen deposition. The impact-pathway approach is applied to follow the emissions from source to impact on human health in Europe (including Denmark) and from source to critical nitrogen load exceedances for NH₃-sensitive nature in Denmark. The Danish Eulerian Hemispheric Model (DEHM) is used for modelling the air pollution concentrations in Europe and nitrogen depositions on land and water surfaces in Denmark arising from NH₃ emissions from mink farming in Denmark. The Economic Valuation of Air (EVA) pollution model system is applied for deriving the health effects and corresponding socio-economic costs in Denmark and Europe arising from the emissions from mink farming. On a local scale in Denmark, the deposition resulting from the NH₃ emissions from mink farming is modelled using the results from the OML-DEP model at a high resolution to derive the critical nitrogen load exceedances for Danish nature areas sensitive to NH₃. From the analysis of the impacts through human exposure to the air pollutants PM_2.5, NO₂, and O₃, it is concluded that in total, ~60 premature deaths annually in Europe, including Denmark, can be attributed to the emissions of NH₃ to the atmosphere from the mink farming sector in Denmark. This corresponds to annual socio-economic costs on the order of EUR 142 million. From the analysis of critical load exceedances, it is concluded that an exceedance of the critical load of nitrogen deposition of ~14,600 hectares (ha) of NH₃-sensitive nature areas in Denmark can be attributed to NH₃ emissions from mink farming. The cost for restoring nature areas of this size, damaged by eutrophication from excess nitrogen deposition, is estimated to be ~EUR 110 million. In 2020, the mink sector in Denmark was shut down in connection with the COVID-19 pandemic. All mink were culled by order of the Danish Government, and now in 2025, the process of determining the level of financial compensation to the farmers is still ongoing. The socio-economic costs following the impacts on human health in Europe and nitrogen-sensitive nature in Denmark of NH₃ emissions from the now non-existing mink sector can therefore be viewed as socio-economic benefits. In this study, these benefits are compared with the expected level of compensation from the Danish Government to the mink farmers, and the conclusion is that the compensation to the mink farmers breaks even with the benefits from reduced NH₃ emissions over a timescale of ~20 years. Full article

Expansion joints mounted on the edges of bridges can cause excessive noise and environmental nuisance. Currently, there are no standardized European methods for assessing the noise of these devices. This article presents the results of investigations of two expansion joint devices: a modular one used for small displacements and a finger one used for large displacements. The method proposed in the Austrian standard was used to evaluate the acoustic effects. The exposure levels of the sound were compared after analyzing 100 reliable car passes through each device. Acoustic signals were recorded and analyzed at three points. In the case of the modular device, the average exposure sound level above the device was 2.6 dB higher than the noise above one outside the device. For a finger device, the difference was 1.2 dB. The latter device can be considered “low-noise”. The amplitude–frequency characteristics of the recorded phenomena were also analyzed to show which frequencies are responsible for excessive noise. The dependence of sound emissions on the speed of cars was also determined. The conducted research has shown that the adopted method can be successfully used for the acoustic evaluation of expansion joint devices. Full article

Potentially toxic elements, such as chromium (Cr) and zinc (Zn), play essential roles in humans and animals. However, the harmful effects of excessive exposure to these elements through food remain unknown. In this sense, this study aimed to evaluate the anthropogenic contamination of chromium and zinc in aquatic biota and seafood consumers. Based on the PRISMA protocol, 67 articles were selected for this systematic review. The main results point to a wide distribution of these elements, which have familiar emission sources in the aquatic environment, especially in highly industrialized regions. Significant concentrations of both have been reported in different fish species, which sometimes represent a non-carcinogenic risk to consumer health and a carcinogenic risk related to Cr exposure. New studies should be encouraged to fill gaps, such as the characterization of the toxicity of these essential elements through fish consumption, determination of limit concentrations updated by international regulatory institutions, especially for zinc, studies on the influence of abiotic factors on the toxicity and bioavailability of elements in the environment, and those that evaluate the bioaccessibility of these elements in a simulated digestion system when in high concentrations. Full article

This study aims to estimate the carbon footprint and relative uncertainties for design components of conventional and geopolymer concrete. All the design components of alkaline-activated geopolymer concrete, such as fly ash, ground granulated blast furnace slag, sodium hydroxide (NaOH), sodium silicate (Na₂SiO₃), superplasticizer, and others, are assessed to reflect the actual scenarios of the carbon footprint. The conjugate application of the life cycle assessment (LCA) tool SimPro 9.4 and @RISK Monte Carlo simulation justifies the variations in carbon emissions rather than a specific determined value for concrete binders, precursors, and filler materials. A reduction of 43% in carbon emissions has been observed by replacing cement with alkali-activated binders. However, the associative uncertainties of chemical admixtures reveal that even a slight increase may cause significant environmental damage rather than its benefit. Pearson correlations of carbon footprint with three admixtures, namely sodium silicate (r = 0.80), sodium hydroxide (r = 0.52), and superplasticizer (r = 0.19), indicate that the shift from cement to alkaline activation needs additional precaution for excessive use. Therefore, a suitable method of manufacturing chemical activators utilizing renewable energy sources may ensure long-term sustainability. Full article

Greenhouse gases, such as carbon dioxide (CO₂), released from excessive fossil fuel consumption, are major contributors to global warming. Understanding the spatial distribution of CO₂ emissions on a refined scale is crucial for promoting green economic development. Xi’an, a key central city in China, serves as the case study for this research. Using nighttime light data from Black Marble, combined with energy statistics and socio-economic information, this study employed spatial analysis to simulate CO₂ emissions on the district and county levels in Xi’an for the years 2012 and 2022. The results indicated that nighttime light data were significantly correlated with CO₂ emissions (linear function; coefficients of determination: 0.7838 and 0.7941 for 2012 and 2022, respectively). The spatial distribution analysis revealed a clear pattern in CO₂ emissions, with higher emissions concentrated in central urban areas and lower emissions in peripheral regions. Additionally, a comparative analysis of carbon emissions and carbon emission intensity across districts and counties between 2012 and 2022 showed that CO₂ emissions in central urban areas had continued to grow and expand, while emission intensity had declined. These findings suggest that the socio-economic development, policy interventions, and industrial structure in Xi’an influence the spatial distribution of CO₂ emissions. Full article

The decarbonization of the operational fleet through the implementation of renewable and low-carbon fuels (LCFs) is considered a key factor in achieving the regulatory greenhouse gas (GHG) reduction targets set by the IMO and the EU. In parallel with optimizing engine energy efficiency and emission characteristics during retrofitting for LCF operations, it is equally important to assess and ensure the reliability of engine components under permissible thermal and mechanical loads. This study investigated the key factors influencing thermal and mechanical stresses on the cylinder–piston assembly components as the engine’s operation shifts from diesel to biodiesel, natural gas, methanol, or ammonia. The methodological foundation of this research was an original comparative analysis method that evaluates the impacts of thermal stress and combustion cycle energy efficiency factors. The combustion cycle energy parameters were modeled using a single-zone mathematical model. The thermal load factor was determined based on the ALPHA (α_gas) coefficient of heat transfer intensity and the average combustion gas temperature (T_avg). The optimization of the combustion cycle during retrofitting was simulated without changes to the engine structure (or without “major” modernization, according to IMO terminology), with modifications limited to the engine’s combustion adjustment parameters. A key characteristic of the transition from diesel to LCFs is a significant increase in the maximum cycle pressure (Pmax), a factor influencing mechanical stresses: ammonia, +43%; LNG, +28%; methanol, +54–70%; biodiesel, no significant changes. This study confirms the adopted strategy to maintain thermal load factors for engine components equal to Dmax conditions. It is emphasized that, after ensuring Pmax-idem conditions, the thermal load during LCF operation aligns closely with the characteristic diesel level with minimal deviation. The thermal load reduction is associated with an increase in the excess air coefficient (λ) and a controlled reduction in the compression ratio within an allowable variation of ±1 unit. Based on statistical correlations, a rational increase in λ was identified, reaching up to 2.5 units. Considering the real-world operational load cycle structure of marine engines, further research will focus on analyzing thermal and mechanical stresses according to ISO 81/78, as well as E2 and E3 operational cycles. Full article

Nitrogen is an essential plant nutrient, but N fertilization contributes to greenhouse gas emissions through its production and application as well as nitrous oxide emissions when applied to soil. Diazotrophic bacteria, known to modify root architecture and increase nutrient uptake, have been proposed as a potential strategy to improve nitrogen use efficiency (NUE) in sugarcane cultivation. The objective of this study was to evaluate the efficiency of N use from ¹⁵N ammonium sulfate applied to different sugarcane varieties inoculated with diazotrophic bacteria. The experiment was conducted in pots filled with soil (100 kg pot⁻¹). The sugarcane varieties tested were RB867515 and RB92579. A commercial diazotrophic bacteria inoculant for sugarcane was used. The experimental design was a randomized block design with four replicates. The treatments were as follows: control without inoculation, inoculation with five strains of bacteria, with or without nitrogen fertilization. The evaluations were performed on different parts of the plant. At 360 days after transplanting, the accumulation of N, fresh mass, dry mass, and the proportion of excess ¹⁵N were determined. In the studied sugarcane varieties, the efficiency of ¹⁵N fertilizer use was 60%, with no influence from inoculation. Full article

Excessive levels of Zn(II) ions in aquatic environments pose significant risks to both ecosystems and human health. In aquatic systems, Zn(II) ions disrupt metabolic functions in organisms, leading to toxicity and bioaccumulation. For humans, prolonged exposure can result in gastrointestinal distress, immune system dysfunction, and neurological complications, necessitating effective removal strategies. This study reports the synthesis and characterization of CoFe-MgO-C-M600 (CoFe₂O₄@MgO@(Mg_0.23Co_0.77)(Mg_0.35Co_1.65)O₄@C) and CoFe-MgO-C-M800 (CoFe₂O₄@MgO@C) nanocomposites for the efficient removal of Zn(II) ions from aqueous media. The nanocomposites were synthesized using the Pechini sol-gel method and characterized through X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM). XRD analysis confirmed the crystalline structure of both nanocomposites, with CoFe-MgO-C-M600 exhibiting a smaller average crystallite size (38.67 nm) than CoFe-MgO-C-M800 (75.48 nm). EDX results verified the elemental composition of the nanocomposites, ensuring the successful incorporation of key elements. FE-SEM analysis revealed significant morphological differences, with CoFe-MgO-C-M600 displaying smaller and more uniform grains compared to CoFe-MgO-C-M800. The results show that CoFe-MgO-C-M600 possesses a highly porous and interconnected structure, enhancing its surface area and adsorption potential. In contrast, CoFe-MgO-C-M800 demonstrates larger and more compact grains, which may affect its adsorption performance. HR-TEM further confirmed these findings, demonstrating that CoFe-MgO-C-M600 had a smaller average particle diameter (35.45 nm) than CoFe-MgO-C-M800 (321.14 nm). Adsorption studies indicated that CoFe-MgO-C-M600 and CoFe-MgO-C-M800 achieved maximum adsorption capacities of 276.24 and 200.00 mg/g, respectively. The adsorption process was determined to be exothermic, spontaneous, and physical in nature, following the pseudo-second-order kinetic model and the Langmuir isotherm. Full article

This paper introduces a novel mathematical model designed to determine combustion characteristics across the length of the combustion zone, underpinned by logical theoretical foundations and demonstrating notable alignment with experimental findings. The model facilitates the calculation of combustion efficiency based on inlet flow parameters (temperature, pressure, velocity, length, porosity, and air excess ratio), achieving efficiencies beyond conventional limits (η = 0.98–0.99) and reaching high values (η = 0.999–0.9999), which is crucial for optimizing low-emission combustors. Verification of the mathematical model was conducted through a dual approach: experimental validation and computational fluid dynamics (CFD) simulations. Comparative analysis revealed a high degree of consistency among theoretical predictions, CFD results, and experimental data, particularly for temperature and combustion efficiency distributions along the combustor length. This robust agreement affirms the model’s accuracy, reliability, and utility in advancing combustion research and developing efficient, low-emission combustors. Full article