Search Results (970)

Methanol/diesel hybrid−powered vessels represent a significant advancement in green and low−carbon innovation in the maritime transportation sector and have been widely adopted across various shipping markets. However, the dual−fuel power system modifies the fire load within the engine room compared to traditional vessels, thereby significantly influencing the fire safety of methanol/diesel−powered ships. In this study, anhydrous methanol and light−duty diesel (with 0 °C pour point) were used as fuels to investigate the mixed combustion characteristics of these immiscible fuels in circular pools with diameters of 6, 10, 14, and 20 cm at various mixing ratios. By analyzing the fuel mass loss rate, flame morphology, and heat transfer characteristics, it was determined that methanol and diesel exhibited distinct stratification during combustion, with the process comprising three phases: pure methanol combustion phase, transitional combustion phase, and pure diesel combustion phase. Slopover occurred during the transitional combustion phase, and its intensity decreased as the pool diameter or methanol fuel quantity increased. Based on this conclusion, a quantitative relationship was established between slopover intensity, pool diameter, and the methanol/diesel volume ratio. Additionally, during the transitional combustion phase, the average flame height exhibited an exponential coupling relationship with the pool diameter and the methanol/diesel volume ratio. Therefore, a modification was made to the classical flame height model to account for these effects. Moreover, a prediction model for the burning rate of methanol/diesel pool fires was established based on transient temperature variations within the fuel layer. This model incorporated a correction factor related to pool diameter and fuel mixture ratio. Additionally, the causes of slopover were analyzed from the perspectives of heat transfer and fire dynamics, further refining the physical interpretation of the correction factor. Full article

The intensification of economic globalization and the growing scarcity of global land resources have magnified the complexity of future land use and land cover (LULC) changes. In Mainland Southeast Asia (MSEA), these transformations are particularly pronounced, yet comprehensive, targeted, and systematic reviews are scant. This research employs bibliometrics and critical literature review methodologies to scrutinize 1956 relevant publications spanning from 1990–2023, revealing key insights into the contributors to land use studies in MSEA, which include not only local researchers from countries like Thailand and Vietnam but also international scholars from the United States, China, Japan, and France. Despite this, the potential for global collaboration has not been fully tapped. This study also notes a significant evolution in data analysis methods, transitioning from reliance on single data sources to employing sophisticated multi-source data fusion, from manual feature extraction to leveraging automated deep learning processes, and from simple temporal change detection to comprehensive time series analysis using tools like Google Earth Engine (GEE). This shift encompasses the progression from small-scale case studies to extensive multi-scale system analyses employing advanced spatial statistical models and integrated technologies. Moreover, the thematic emphasis of research has evolved markedly, transitioning from traditional practices like slash-and-burn agriculture and deforestation logging to the dynamic monitoring of specialized tree species such as rubber plantations and mangroves. Throughout this period, there has been a growing focus on the broad environmental impacts of land cover change, encompassing soil degradation, carbon storage, climate change responses, ecosystem services, and biodiversity. This research not only offers a comprehensive understanding of the LULC research landscape in MSEA but also provides critical scientific references that can inform future policy-making and land management strategies. Full article

Biomass burning (BB) results from complex interactions between ecosystems, humans, and climate, releasing large amounts of gases and particles. Accurate BB emission estimates are essential for air quality, climate studies, and impact assessments. Various existing bottom-up BB emission inventories show significant discrepancies, varying by factors of 2 to 4 due to uncertainties in burned areas (BAs), emission factors (EFs), and vegetation parameters such as biomass density (BD) and burning efficiency (BE). Here, we investigate the role of vegetation parameters in these discrepancies in Africa. Two BB emission inventories, AMMABB-like (African Monsoon Multidisciplinary Analysis Biomass Burning) and GFED-like (Global Fire Emission Database) were developed for Organic Carbon (OC) and Black Carbon (BC). Both inventories used identical fire products, vegetation maps, and EF but different BD and BE values. Results highlight substantial differences in BD and BE, with relative gaps ranging from 44% to 85.12%, explaining the observed differences between BB emission inventories. Key vegetation classes responsible for BB emissions were identified. Discrepancies of 2.4 to 3.9 times were observed between AMMABB-like and GFED4-like, with higher values in the Southern Hemisphere. Better BD and BE estimates with regional distinctions for both hemispheres would improve BB emission accuracy in Africa. Full article

Lignin is the largest renewable source of aromatic biopolymers on Earth, and it is commercially available as by-product of biorefineries and pulp/paper industries. It is mainly burned for heat and power, but pyrolysis can provide high-value-added products. In this study, the pyrolysis characteristics of alkali lignin pellets are investigated using a packed-bed reactor at a laboratory scale for heating temperatures of 800–900 K. Conversion dynamics are analyzed by means of the thermal field and the rates of gaseous species release, which is a very innovative aspect of the study. The yields of the lumped product classes do not vary significantly in the range of heating temperatures examined (biochar yields around 58–63 wt%, together with gas and liquid yields around 9–12 and 28–30 wt%, respectively). Carbon dioxide is the most abundant gaseous product, followed by methane and carbon monoxide (smaller amounts of C₂ hydrocarbons and hydrogen), while bio-oil is rich in phenolic compounds, especially guaiacols, cresols, and phenol. A comparison with the conversion dynamics of fir, beech, and straw reveals that, mainly as a consequence of softening and melting, the lignin heat- and mass-transfer rates as well as actual reaction temperatures are profoundly different. In fact, the characteristic process size becomes the diameter of the reactor rather than that of the pellets. Full article

One of the approaches to limit the negative impact on the environment from the burning of coal in the production of heat and electricity is to limit their use by blending them with biomass. Blended fuel combustion leads to the generation of a solid ash residue differing in composition from coal ash, and opportunities for its utilization have not yet been studied. The present paper provides results on the carbon capture potential of adsorbents developed through the alkaline conversion of ash mixtures from the combustion of lignite and biomass from agricultural plants and wood. The raw materials and the obtained adsorbents were studied with respect to the following: their chemical and phase composition based on Atomic Absorption Spectroscopy with Inductively Coupled Plasma (AAS-ICP) and X-ray powder diffraction (XRD), respectively, morphology based on scanning electron spectroscopy (SEM), thermal properties based on thermal analysis (TG and DTG), surface parameters based on N₂ physisorption, and the type of metal oxides within the adsorbents based on temperature-programmed reduction (TPR) and UV-VIS spectroscopy. The adsorption capacity toward CO₂ was studied in dynamic conditions and the obtained results were compared to those of zeolite-like CO₂ adsorbents developed through the utilization of the raw coal ash. It was observed that the adsorbents based on ash of blended fuel have a comparable carbon capture potential with coal fly ash zeolites despite their lower specific surface areas due to their compositional specifics and that they could be successfully applied as adsorbents in post-combustion carbon capture systems. Full article

Fires drive global ecosystem change, impacting carbon dynamics, atmospheric composition, biodiversity, and human well-being. Biomass burning, a major outcome of fires, significantly contributes to greenhouse gas and aerosol emissions. Among these, fine particulate matter (PM_2.5) is particularly concerning due to its adverse effects on air quality and health, and its substantial yet uncertain role in Earth’s energy balance. Variability in emission factors (EFs) remains a key source of uncertainty in emission estimates. This study evaluates PM_2.5 emission sensitivity to EFs variability in Brazil’s Amazon and Cerrado biomes over 2002–2023 using the 3BEM_FRP model implemented in the PREP-CHEM-SRC tool. We updated the EFs with values and uncertainty ranges from Andreae (2019), which reflect a more comprehensive literature review than earlier datasets. The results reveal that the annual average PM_2.5 emissions varied by up to 162% in the Amazon (1213 Gg yr⁻¹ to 3172 Gg yr⁻¹) and 184% in the Cerrado (601 Gg yr⁻¹ to 1709 Gg yr⁻¹). The Average peak emissions at the grid-cell level reached 5688 Mg yr⁻¹ in the “Arc of Deforestation” region under the High-end EF scenario. Notably, the PM_2.5 emissions from Amazon forest areas increased over time despite shrinking forest cover, indicating that Amazonian forests are becoming more vulnerable to fire. In the Cerrado, savannas are the primary land cover contributing to the total PM_2.5 emissions, accounting for 64% to 80%. These findings underscore the importance of accurate, region-specific EFs for improving emission models and reducing uncertainties. Full article

Mountain photovoltaic (PV) power stations cover vast areas and contain dense equipment. Once direct current arc faults occur in PV modules, they can pose a serious thermal threat to surrounding facilities and combustible materials, potentially resulting in a PV array fire accident. In this work, a series of PV module fire experiments were conducted to investigate the burning characteristics of PV modules exposed to the pool fire. The burning process, burning damage extent, and temperature distribution were measured and analyzed. The results showed that the surfaces of PV modules exhibited different burning characteristics due to the pool fire. Based on different characteristics, the front side was classified into four zones: intact zone, delamination zone, carbonization zone and burn-through zone. The back side was similarly divided into four zones: undamaged backsheet zone, burnt TPT zone, cell detachment zone and burn-through zone. Meanwhile, the burning process and surface temperature rise rate of intact PV modules were significantly lower than those of cracked modules at the same inclination angle. Cracked modules exhibited a heightened susceptibility to being rapidly burnt through by the pool fire. As the inclination angle increased from 0° to 60°, the burning damage extent and the expansion rate of high-temperature regions initially ascended and subsequently decreased, reaching their maximum at the inclination angle of 15°. These findings can offer valuable insights that can serve as a reference for the fire protection design and risk assessment of mountain PV power stations, ensuring their safe operation. Full article

Agroforestry contributes to slowing deforestation, favoring ecosystem regeneration and improving land use sustainability. This study evaluated the impact of silvopastoral systems on soil recovery and their capacity to sequester and stabilize carbon (C) and nitrogen (N) in degraded soils of a native Nothofagus obliqua forest in Ranchillo Alto (37°04′52″ S, 71°39′14″ W), Ñuble Region, Chile. Three open (Op), semi-open (SOp), and semi-closed (SC) silvopastoral systems were analyzed and compared with a control (Ctr) without silvopastoral management across four soil depths (0–10, 10–20, 20–30, 30–60 cm). Physical, chemical, and biological analyses were performed, along with soil physical organic matter (SOM) fractionation. The highest C levels were found in the 0–10 cm depth (13.9, 11.8, 11.5, and 8.5% for Op > SC > SOp and Ctr, respectively). Despite its higher degradation, Op presented the highest levels of C, N, and non-oxidizable C (Cnox), possibly due to pyrogenic carbon from old potato burns. Furthermore, the same trend was observed for mineral associated organic matter (MAOM) fraction and C stocks in all silvopastoral systems compared to the control. These results underline the potential of silvopastoral practices to improve soil quality and increase long-term carbon sequestration, contributing to sustainable soil restoration strategies. Full article

COPD induced by biomass-burning smoke is a public health problem in developing countries. Biomass-based fuels are ineffective and deliver elevated levels of carbon monoxide, polycyclic aromatic hydrocarbons, and fine particulate matter. PRSS23 participates in extracellular matrix remodeling processes in COPD patients. Our objective was to estimate the DNA methylation levels of cg23771366 (PRSS23) and their clinical relevance in COPD caused by chronic exposure to biomass-burning smoke (BBS). We included 80 women with COPD (COPD-BBS) (≥200 h per year), 180 women with exposure to BBS (≥200 h per year) but without COPD (BBES), and 79 lung-healthy women (HW) without exposure to biomass-burning smoke. The DNA methylation analysis shows significant differences between the three groups included in this study (p < 0.001). HW had high methylation levels (100%) in cg23771366 (PRSS23). In comparison, COPD-BBS and BBES had low levels [0.91% vs. 9.17%, respectively], showing statistically significant differences (p = 0.011) between both groups, with the COPD-BBS presenting the lowest levels in the methylation of cg23771366. In conclusion, chronic biomass-burning smoke exposure is associated with decreased levels of DNA methylation at the CpG cg23771366 site in PRSS23, reinforcing the relationship between PRSS23 and particulate matter. Full article

A carbon-negative heating system can be realized by pyrolyzing wood pellets, burning the product gas, and storing the produced biochar. Oxidative pyrolysis simplifies the reactor design by replacing an external heat supply with internal oxidation driven by a sub-stoichiometric “primary” air supply. Previous studies have only examined the influence of primary air supply on biochar yield and heating power in a continuous pyrolysis reactor within a limited fuel–air spectrum. In this work, an oxidative pyrolysis reactor, with a nominal heating power of 15 kW, was investigated with the aim to vary the useful heat output and biochar yield over a wide range and still produce biochar of the highest quality in accordance with the EBC (European Biochar Certificate) guidelines. This study demonstrated that within an air flux range of 0.03–0.14 kg/(m²s), there is a linear relationship between air flux and both wood flux and useful heat, resulting in a power output range of 4–30 kW. The useful heat output could be varied by a factor of three in less than 15 min, verifying concept feasibility as a central heating system to meet the variable heating demands of both single and multi-household applications. The biochar yield was observed to range from 12% to 24% of the incoming wood mass flow, meeting the EBC Feed Plus quality standards at all conditions. Depending on the operating point, up to 40% of the biomass’s heating value is stored in the biochar. Full article

With the growing trend towards the electrification of transport, it is anticipated that internal combustion engines will continue to play an important role in the production of electricity for electricity systems or the direct propulsion of vehicles. However, these engines are under considerable pressure to achieve carbon neutrality, making zero-emission fuels a key solution. One solution is the use of hydrogen, which is an extremely clean and carbon-free fuel whose combustion product is only water. The paper also introduces the KEYOU concept, which involves switching from burning propellant oil to a supercharged, lean-burn, hydrogen-fueled ignition engine. The authors provide a study on the selected issues based on 113 reviewed literature sources and highlight the achievements and potential of hydrogen engines. Based on the achievements described, the paper provides a comprehensive overview of the impact of hydrogen engines in reducing emissions as well as supporting the sustainable development of transport systems. The literature research conducted highlights hydrogen as an important solution for decarbonizing internal combustion engines and moving towards an emission-free future. Full article

Polyurethane foam (PF) is a versatile polymer widely used in various applications. By changing the composition of polyol and isocyanate, these foams can be classified into rigid polyurethane foams (PUFRs) and flexible polyurethane foams (PUFFs). The flexible polyurethane foam (PUFFs) is well known for its sound absorption capacities; nevertheless, its flammability poses significant safety hazards. The purpose of this study is to look into how flexible polyurethane foam reacts to fire, specifically its combustion properties, and the risks that come with them. The study aims to find out the rates of horizontal and vertical burning, the make-up of the reaction products, and the temperatures that build up inside the polyurethane foam mass when a support pole is placed in front of the stage and sound-absorbing material is added to stop stage sounds from reverberating. There were performed experiments to determine the fire behavior of the samples in contact with an ignition source in the form of a small flame and experiments to determine the ignition temperature of the sound-absorbing sponge, where it was found that vertical position accelerates combustion, and in practical applications, this aspect must be considered for fire prevention. To determine the combustion gases, several methods were used, namely spectrophotometric, ion chromatography, and gas-chromatographic methods. Analysis of the gases resulting from the combustion of the sound-absorbing sponge indicates the presence of dangerous toxic compounds (hydrogen cyanide, carbon monoxide, and hydrochloric acid), which can endanger human health in the event of a fire. Full article

Soil microbes are critical in regulating the growth and function of eucalyptus plantations. The mechanisms underlying soil microbial communities’ response to different eucalyptus plantation management practices remain elusive. In this study, we compiled datasets containing 2744 observations across global eucalyptus-planted regions and analyzed the effects of five management practices (i.e., burning, residual removal, fertilization, mixed planting, and controlling planting years) on soil microbial biomass, diversity, and structures. Our results showed that fungal community alpha diversity responds more sensitively to management practices than bacterial community alpha diversity on eucalyptus plantations. Although the implementation of management practices significantly increased the content of most soil nutrients and microbial biomass elements (excluding burning), these practices did not necessarily improve soil microbial biomass and diversity, particularly among fungal communities. Burning, fertilization, and mixing eucalyptus with nitrogen-fixing species significantly decreased the diversity of fungal communities, which were mainly impacted by soil organic carbon and total potassium content. Compared to the four other management practices, mixing eucalyptus with nitrogen-fixing species favored the growth of bacterial communities and the storage of microbial biomass nitrogen, making it the most effective management practice. However, attention should also be paid to the protection of fungal communities. In addition, these management practices significantly changed microbial community structures, which were positively correlated with the microbial biomass elements carbon and nitrogen and, to a lesser extent, soil microbial alpha diversity. Our results highlight the importance of prioritizing mixing eucalyptus with nitrogen-fixing species as a management practice and safeguarding fungal community diversity during its implementation and suggest that microbial diversity development associated with soil organic carbon and potassium contents should be given priority in eucalyptus plantation management. Full article

As part of the transition to low-carbon energy and for the sustainable utilisation of resources, it is necessary to seek a replacement for solid fossil fuels, but unfortunately, it is impossible to completely abandon them for various reasons at the moment, so only partial replacement with new, high-calorific, biomass-based fuels is possible. The purpose of this work is to determine the typical parameters of the co-combustion of carbonisate, coal and their mixtures, taking into account the synergetic effects influencing the combustion intensity of the mixture. Carbonisate was obtained in the process of the gasification of pinewood through the counter-blowing method at a temperature of 800–900 °C, while air was used as an oxidant. Basically, this method of gasification is used for coal in order to obtain high-calorific coke for the metallurgical industry. Also, in this study, for the first time, carbonisate was obtained from 50% pinewood and 50% lignite. The O/C and H/C ratios were determined for carbonisate. A technical and elemental analysis of the investigated fuels was carried out. A thermal analysis in oxidising medium was applied to determining the typical combustion parameters in the process of slow heating of the fuels under study. According to the results of this thermal analysis, typical heating parameters such as the ignition temperature, burnout temperature, maximum mass loss rate, combustion index, etc., were determined. It was noted that the calorific value of carbonised wood is two times higher than that of coal. The combustion index of carbonisates is 2.5–36% lower compared to that of coal. According to the results of the analysis of the interaction of the components among themselves (in the process of their joint combustion), the presence of synergetic interactions between the components was determined, which affected the change in the combustion intensity and heat release intensity. The results of this study may be useful for retrofitting coal-fired boilers to run on a mixture containing carbonisate and lignite. If carbonisate is produced from biomass, the resulting gas could be used as an energy fuel by burning it in a coal-fired boiler. Full article

The concept of the sustainable development of the world economy is currently aimed at achieving carbon neutrality, and this is due to the global warming of the planet. Energy and construction make a significant contribution to the release of carbon emissions into the environment and atmosphere. According to statistics, simply burning one ton of Portland cement clinker provokes the release of at least half a ton of carbon dioxide. In this study, the prepared samples were subjected to electron diffraction studies, as well as the X-ray phase analysis of the zone (XRF) using an ARLX’TRA diffractometer. Studies of macro- and microstructures were carried out using a Quanta 3D 200i scanning microscope. The obtained spectra were processed using EDAX TEAM software. The study of the microstructure of the samples showed that the bulk of the heterogeneous systems consisted of volumetric aggregates and intergrowths, i.e., small accumulations on their surfaces with pronounced cleavage, features of the microstructure indicating mineral formation processes. Therefore, the development of low-carbon construction models will make it possible to make a contribution and open an effective path to the implementation of climate policy through the rational use of natural resources and the involvement of industrial waste and nature-like technologies in the production process. In this regard, one of the options for solving the identified problems is to revise existing technologies and develop low-carbon, low-clinker binders using industrial waste and substandard raw materials. Full article