Letícia Gomes, Jéssica Schüler, Camila Silva, Ane Alencar, Bárbara Zimbres, Vera Arruda, Wallace Vieira da Silva, Edriano Souza, J. Shimbo, B. Marimon, E. Lenza, C. W. Fagg, Sabrina Miranda, P. Morandi, B. H. Marimon‐Junior, Mercedes Bustamante
Savannas play a key role in estimating emissions. Climate change has impacted the Cerrado savanna carbon balance. We used the burned area product and long-term field inventories on post-fire vegetation regrowth to estimate the impact of the fire on greenhouse gas emissions and net carbon dioxide (CO2) emissions in the Cerrado savanna between 1985 and 2020. We estimated the immediate emissions from fires, CO2 emissions by plant mortality, and CO2 removal from vegetation regrowth. The burned area was 29,433 km2; savanna fires emitted approximately 2,227,964 Gg of CO2, 85,057 Gg of CO, 3010 Gg of CH4, 5,103 Gg of NOx, and 275 Gg of N2O. We simulated vegetation regrowth according to three fire regime scenarios: extreme (high fire frequency and short fire interval), intermediate (medium fire frequency and medium fire interval), and moderate (low fire frequency and long fire interval). Under the extreme and intermediate scenarios, the vegetation biomass decreased by 2.0 and 0.4% (ton/ha-year), while the biomass increased by 2.1% under a moderate scenario. We converted this biomass into CO2 and showed that the vegetation regrowth removed 63.5% of the total CO2 emitted (2,355,426 Gg), indicating that the Cerrado savanna has been a source of CO2 to the atmosphere.
{"title":"Impacts of Fire Frequency on Net CO2 Emissions in the Cerrado Savanna Vegetation","authors":"Letícia Gomes, Jéssica Schüler, Camila Silva, Ane Alencar, Bárbara Zimbres, Vera Arruda, Wallace Vieira da Silva, Edriano Souza, J. Shimbo, B. Marimon, E. Lenza, C. W. Fagg, Sabrina Miranda, P. Morandi, B. H. Marimon‐Junior, Mercedes Bustamante","doi":"10.3390/fire7080280","DOIUrl":"https://doi.org/10.3390/fire7080280","url":null,"abstract":"Savannas play a key role in estimating emissions. Climate change has impacted the Cerrado savanna carbon balance. We used the burned area product and long-term field inventories on post-fire vegetation regrowth to estimate the impact of the fire on greenhouse gas emissions and net carbon dioxide (CO2) emissions in the Cerrado savanna between 1985 and 2020. We estimated the immediate emissions from fires, CO2 emissions by plant mortality, and CO2 removal from vegetation regrowth. The burned area was 29,433 km2; savanna fires emitted approximately 2,227,964 Gg of CO2, 85,057 Gg of CO, 3010 Gg of CH4, 5,103 Gg of NOx, and 275 Gg of N2O. We simulated vegetation regrowth according to three fire regime scenarios: extreme (high fire frequency and short fire interval), intermediate (medium fire frequency and medium fire interval), and moderate (low fire frequency and long fire interval). Under the extreme and intermediate scenarios, the vegetation biomass decreased by 2.0 and 0.4% (ton/ha-year), while the biomass increased by 2.1% under a moderate scenario. We converted this biomass into CO2 and showed that the vegetation regrowth removed 63.5% of the total CO2 emitted (2,355,426 Gg), indicating that the Cerrado savanna has been a source of CO2 to the atmosphere.","PeriodicalId":12279,"journal":{"name":"Fire","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141925081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stavros Kalogiannidis, D. Kalfas, Theoxaris Zagkas, F. Chatzitheodoridis
The current study attempts to assess the effect of community preparedness on property damage costs during wildfires. The focus is primarily on how various aspects of community preparedness, such as early warning systems, early risk assessment, emergency response plans, and fire-resistant landscaping, influence the extent of property damage costs during wildfires. For this purpose, data were collected from 384 Greek residents from different regions of the country using an online questionnaire. In this case, analysis was performed utilizing SPSS version 22.0. According to the findings, survey respondents replied that fire suppression was the most common property cost associated with wildfire. The study contributes to existing knowledge by providing insights into the specific factors that affect property damage expenditure during wildfires, specifically the intricate relationship between the expenses of property loss caused by wildfires and community preparation. The study’s findings can be utilized by policymakers and communities to improve preparedness plans and consequently decrease the impact of wildfires on property and people.
{"title":"Assessing the Effect of Community Preparedness on Property Damage Costs during Wildfires: A Case Study of Greece","authors":"Stavros Kalogiannidis, D. Kalfas, Theoxaris Zagkas, F. Chatzitheodoridis","doi":"10.3390/fire7080279","DOIUrl":"https://doi.org/10.3390/fire7080279","url":null,"abstract":"The current study attempts to assess the effect of community preparedness on property damage costs during wildfires. The focus is primarily on how various aspects of community preparedness, such as early warning systems, early risk assessment, emergency response plans, and fire-resistant landscaping, influence the extent of property damage costs during wildfires. For this purpose, data were collected from 384 Greek residents from different regions of the country using an online questionnaire. In this case, analysis was performed utilizing SPSS version 22.0. According to the findings, survey respondents replied that fire suppression was the most common property cost associated with wildfire. The study contributes to existing knowledge by providing insights into the specific factors that affect property damage expenditure during wildfires, specifically the intricate relationship between the expenses of property loss caused by wildfires and community preparation. The study’s findings can be utilized by policymakers and communities to improve preparedness plans and consequently decrease the impact of wildfires on property and people.","PeriodicalId":12279,"journal":{"name":"Fire","volume":"53 38","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141929302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, a tunnel model with a length of 20 m, a width of 5 m, and a height of 5 m was used, and an experimental investigation was conducted to examine the impact of high-pressure water mist on the temperature distribution along the tunnel ceiling. Specifically, different experimental settings, such as various nozzle pressures, nozzle positions, and longitudinal ventilation speeds, in the high-pressure water mist system were employed to investigate the smoke-spreading process of tunnel fire under different conditions, and an effective method utilizing a high-pressure water mist system was proposed for blocking smoke and heat. The experimental results reveal that the high-pressure water mist system can be used to effectively improve the ceiling temperature during tunnel fires; when the nozzle pressure is set as 10 MPa, and the nozzle position is located at x7, the highest thermal insulation efficiency in the tunnel is obtained. Additionally, the joint application of the high-pressure water mist system and the mechanical smoke exhaust effectively mitigates the ambient temperature within the tunnel, thereby playing a pivotal role in enhancing the fire safety of the tunnel.
{"title":"Experimental Study on the Influence of High-Pressure Water Mist on the Ceiling Temperature of a Longitudinally Ventilated Tunnel","authors":"Hui Zhu, Weining Du, Wenfeng Li","doi":"10.3390/fire7080262","DOIUrl":"https://doi.org/10.3390/fire7080262","url":null,"abstract":"In this study, a tunnel model with a length of 20 m, a width of 5 m, and a height of 5 m was used, and an experimental investigation was conducted to examine the impact of high-pressure water mist on the temperature distribution along the tunnel ceiling. Specifically, different experimental settings, such as various nozzle pressures, nozzle positions, and longitudinal ventilation speeds, in the high-pressure water mist system were employed to investigate the smoke-spreading process of tunnel fire under different conditions, and an effective method utilizing a high-pressure water mist system was proposed for blocking smoke and heat. The experimental results reveal that the high-pressure water mist system can be used to effectively improve the ceiling temperature during tunnel fires; when the nozzle pressure is set as 10 MPa, and the nozzle position is located at x7, the highest thermal insulation efficiency in the tunnel is obtained. Additionally, the joint application of the high-pressure water mist system and the mechanical smoke exhaust effectively mitigates the ambient temperature within the tunnel, thereby playing a pivotal role in enhancing the fire safety of the tunnel.","PeriodicalId":12279,"journal":{"name":"Fire","volume":"84 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141812758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tiago Bastos, Leonor C. Teixeira, Leonel J. R. Nunes
Rural fires have been a constant concern, with most being associated with land abandonment. However, some fires occur due to negligent attitudes towards fire, which is often used to remove agroforestry leftovers. In addition to the fire risk, this burning also represents a waste of the energy present in this residual biomass. Both rural fires and energy waste affect the three dimensions of sustainability. The ideal solution seems to be to use this biomass, avoiding the need for burning and recovering the energy potential. However, this process is strongly affected by logistical costs, making this recovery unfeasible. In this context, this study aims to propose an optimization model for this chain, focusing on the three dimensions of sustainability. The results of the present study comprise a summary of the current state of the art in supply-chain optimization, as well as a disruptive mathematical model to optimize the residual biomass supply chain. To achieve this objective, a literature review was carried out in the first phase, incorporating the specificities of the context under study to arrive at the final model. To conclude, this study provides a review covering several metaheuristics, including ant colony optimization, genetic algorithms, particle swarm optimization, and simulated annealing, which can be used in this context, adding another valuable input to the final discussion.
{"title":"Fire Risk Reduction and Recover Energy Potential: A Disruptive Theoretical Optimization Model to the Residual Biomass Supply Chain","authors":"Tiago Bastos, Leonor C. Teixeira, Leonel J. R. Nunes","doi":"10.3390/fire7080263","DOIUrl":"https://doi.org/10.3390/fire7080263","url":null,"abstract":"Rural fires have been a constant concern, with most being associated with land abandonment. However, some fires occur due to negligent attitudes towards fire, which is often used to remove agroforestry leftovers. In addition to the fire risk, this burning also represents a waste of the energy present in this residual biomass. Both rural fires and energy waste affect the three dimensions of sustainability. The ideal solution seems to be to use this biomass, avoiding the need for burning and recovering the energy potential. However, this process is strongly affected by logistical costs, making this recovery unfeasible. In this context, this study aims to propose an optimization model for this chain, focusing on the three dimensions of sustainability. The results of the present study comprise a summary of the current state of the art in supply-chain optimization, as well as a disruptive mathematical model to optimize the residual biomass supply chain. To achieve this objective, a literature review was carried out in the first phase, incorporating the specificities of the context under study to arrive at the final model. To conclude, this study provides a review covering several metaheuristics, including ant colony optimization, genetic algorithms, particle swarm optimization, and simulated annealing, which can be used in this context, adding another valuable input to the final discussion.","PeriodicalId":12279,"journal":{"name":"Fire","volume":"9 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141810768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper aimed to provide technical support for fuel management by exploring different strengths of fuel removal on the physical and chemical properties and flammability of Betula platyphylla forests in the wildland–urban interface. After investigating the northeastern region during the forest fire prevention period in May 2023, a typical WUI area was selected, and three different treatment strengths, combined with a control, were set up to carry out indoor and outdoor experiments for 27 weeks. Compared with previous studies, this study mainly investigated and analyzed the dynamic changes in the physical and chemical properties and fuel flammability after different intensities of treatments on a time scale. By processing and analyzing the data, the following results were obtained. Significant differences existed in the fuel loading of different time-lag fuels over time (p < 0.05). The ash and ignition point of 1 h time-lag fuel after different treatment intensities generally increased first and then decreased, and the higher heat value and ash-free calorific value generally decreased first and then increased. The physical and chemical properties of 10 h and 100 h time-lag fuel fluctuated with time, but the overall change was insignificant. The indicator that had the greatest impact on the combustion comprehensive score for different time-lag fuels was fuel loading. The change in the flammability of dead surface fuel with time varied significantly, and different treatment intensities effectively reduced the fuel’s flammability. The reduction effects, presented in descending order, were as follows: medium-strength treatment > low-strength treatment > high-strength treatment > control check. In conclusion, different treatment intensities have significant effects on the flammability of the fuel, and the medium-strength treatment has the best effect. Considering the ecological and economic benefits, adopting the medium-strength treatment for the WUI to regulate the fuel is recommended.
本文旨在通过探讨不同强度的燃料清除对荒地-城市结合部桦树林理化性质和可燃性的影响，为燃料管理提供技术支持。经过对东北地区2023年5月森林防火期的调查，选取了典型的WUI区域，设置了三种不同的处理强度，结合对照，开展了为期27周的室内外实验。与以往研究相比，本研究主要调查和分析不同强度处理后，燃料的理化性质和可燃性在时间尺度上的动态变化。通过对数据的处理和分析，得出以下结果。不同时滞燃料的燃料负荷随时间的变化存在显著差异（p < 0.05）。不同处理强度后 1 h 时滞燃料的灰分和燃点一般先升高后降低，高热值和无灰热值一般先降低后升高。10 h 和 100 h 时滞燃料的物理和化学性质随时间有所波动，但总体变化不大。对不同时滞燃料燃烧综合评分影响最大的指标是燃料负荷。死面燃料的可燃性随时间的变化很大，不同的处理强度有效地降低了燃料的可燃性。降低效果从高到低依次为：中强度处理 > 低强度处理 > 高强度处理 > 对照检查。总之，不同的处理强度对燃料的可燃性有显著影响，其中中强度处理的效果最好。考虑到生态效益和经济效益，建议对 WUI 采用中强度处理来调节燃料。
{"title":"Effects of Fuel Removal on the Flammability of Surface Fuels in Betula platyphylla in the Wildland–Urban Interface","authors":"Xintong Chen, Mingyu Wang, Baozhong Li, Lixuan Wang, Jibin Ning, Guang Yang, Hongzhou Yu","doi":"10.3390/fire7070261","DOIUrl":"https://doi.org/10.3390/fire7070261","url":null,"abstract":"This paper aimed to provide technical support for fuel management by exploring different strengths of fuel removal on the physical and chemical properties and flammability of Betula platyphylla forests in the wildland–urban interface. After investigating the northeastern region during the forest fire prevention period in May 2023, a typical WUI area was selected, and three different treatment strengths, combined with a control, were set up to carry out indoor and outdoor experiments for 27 weeks. Compared with previous studies, this study mainly investigated and analyzed the dynamic changes in the physical and chemical properties and fuel flammability after different intensities of treatments on a time scale. By processing and analyzing the data, the following results were obtained. Significant differences existed in the fuel loading of different time-lag fuels over time (p < 0.05). The ash and ignition point of 1 h time-lag fuel after different treatment intensities generally increased first and then decreased, and the higher heat value and ash-free calorific value generally decreased first and then increased. The physical and chemical properties of 10 h and 100 h time-lag fuel fluctuated with time, but the overall change was insignificant. The indicator that had the greatest impact on the combustion comprehensive score for different time-lag fuels was fuel loading. The change in the flammability of dead surface fuel with time varied significantly, and different treatment intensities effectively reduced the fuel’s flammability. The reduction effects, presented in descending order, were as follows: medium-strength treatment > low-strength treatment > high-strength treatment > control check. In conclusion, different treatment intensities have significant effects on the flammability of the fuel, and the medium-strength treatment has the best effect. Considering the ecological and economic benefits, adopting the medium-strength treatment for the WUI to regulate the fuel is recommended.","PeriodicalId":12279,"journal":{"name":"Fire","volume":"20 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141815718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Melida Roman, Ricardo Zubieta, Yerson Ccanchi, Alejandra Martínez, Y. Paucar, Sigrid Alvarez, Julio Loayza, Filomeno Ayala
Soils are a valuable renewable resource on human timescales, and they interact with distinctive grassland ecosystems characterized by unique biodiversity and essential provision of ecosystem services, such as water supply and carbon sequestration. However, knowledge of the effects of wildfires on soil properties and nutrient availability in the Andes remains limited. Andean grasslands are currently one of the ecosystems of the Peruvian Andes most affected by wildfires. Our objective is to analyze the effect of fire activity on the physicochemical properties of soil and analyze its social context in Cusco, in the southern Andes of Peru. Soil samples were collected during five periods, spanning both the dry and rainy seasons, to characterize changes in soil properties and monitor vegetation recovery post-fire in two local communities dedicated to livestock activities. The vegetation restored after the wildfire was measured by the “step transect” method. Post-fire changes in soil properties indicate slight increases in pH, electrical conductivity, organic matter, nitrogen, phosphorus, and potassium during the onset of the rainy season; thereafter, a gradual reduction in these values was observed. This reduction can be attributed to leaching associated with the seasonal rainfall and runoff regime. Our findings indicate that one-year post-fire, the biomass in burned areas is reduced to 30–46% of the biomass in unburned areas. A complete regeneration is likely to occur in up to 4 years; this assertion is supported by the perceptions of the affected population, as expressed in interviews conducted in the two farming communities. These results are significant for decision-makers formulation of policies and regulations regarding grasslands and their seasonal restoration.
{"title":"Seasonal Effects of Wildfires on the Physical and Chemical Properties of Soil in Andean Grassland Ecosystems in Cusco, Peru: Pending Challenges","authors":"Melida Roman, Ricardo Zubieta, Yerson Ccanchi, Alejandra Martínez, Y. Paucar, Sigrid Alvarez, Julio Loayza, Filomeno Ayala","doi":"10.3390/fire7070259","DOIUrl":"https://doi.org/10.3390/fire7070259","url":null,"abstract":"Soils are a valuable renewable resource on human timescales, and they interact with distinctive grassland ecosystems characterized by unique biodiversity and essential provision of ecosystem services, such as water supply and carbon sequestration. However, knowledge of the effects of wildfires on soil properties and nutrient availability in the Andes remains limited. Andean grasslands are currently one of the ecosystems of the Peruvian Andes most affected by wildfires. Our objective is to analyze the effect of fire activity on the physicochemical properties of soil and analyze its social context in Cusco, in the southern Andes of Peru. Soil samples were collected during five periods, spanning both the dry and rainy seasons, to characterize changes in soil properties and monitor vegetation recovery post-fire in two local communities dedicated to livestock activities. The vegetation restored after the wildfire was measured by the “step transect” method. Post-fire changes in soil properties indicate slight increases in pH, electrical conductivity, organic matter, nitrogen, phosphorus, and potassium during the onset of the rainy season; thereafter, a gradual reduction in these values was observed. This reduction can be attributed to leaching associated with the seasonal rainfall and runoff regime. Our findings indicate that one-year post-fire, the biomass in burned areas is reduced to 30–46% of the biomass in unburned areas. A complete regeneration is likely to occur in up to 4 years; this assertion is supported by the perceptions of the affected population, as expressed in interviews conducted in the two farming communities. These results are significant for decision-makers formulation of policies and regulations regarding grasslands and their seasonal restoration.","PeriodicalId":12279,"journal":{"name":"Fire","volume":"89 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141818636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In small and medium-sized chemical plants, explosions constantly occur owing to runaway reactions because of equipment defects or human errors and so on. Accordingly, in this study, based on a case study of an explosion accident in a polystyrene reactor in South Korea, the dis-charge capacity of hazardous substances during a runaway reaction is reviewed and a method for safely disposing of hazardous substances is proposed. Using an acceleration rate calorimeter, the maximum temperature rise rate during the polystyrene reaction was determined, and it was determined that 355,643 kg/h can flow during a runaway reaction. A 30-inch header size was then selected to consider maximum flow rate, and two 81.4 m2 heat exchangers were selected to completely condense the hazardous substances. As a result, the facilities at the workplace were configured to condense all hazardous substances and discharge them into the atmosphere. If this method is used, it is believed that the lives of workers can be protected by preventing fires and explosions in small and medium-sized chemical plants in which runaway reactions may occur.
{"title":"Safety Design Criteria for the Emergency Discharge of Hazardous Substances in Small and Medium-Sized Polystyrene Polymerization Batch Reactor Processes: Case Study of the South Korean Chemical Industry","authors":"Sang-Ryung Kim, Sang-Gil Kim","doi":"10.3390/fire7070260","DOIUrl":"https://doi.org/10.3390/fire7070260","url":null,"abstract":"In small and medium-sized chemical plants, explosions constantly occur owing to runaway reactions because of equipment defects or human errors and so on. Accordingly, in this study, based on a case study of an explosion accident in a polystyrene reactor in South Korea, the dis-charge capacity of hazardous substances during a runaway reaction is reviewed and a method for safely disposing of hazardous substances is proposed. Using an acceleration rate calorimeter, the maximum temperature rise rate during the polystyrene reaction was determined, and it was determined that 355,643 kg/h can flow during a runaway reaction. A 30-inch header size was then selected to consider maximum flow rate, and two 81.4 m2 heat exchangers were selected to completely condense the hazardous substances. As a result, the facilities at the workplace were configured to condense all hazardous substances and discharge them into the atmosphere. If this method is used, it is believed that the lives of workers can be protected by preventing fires and explosions in small and medium-sized chemical plants in which runaway reactions may occur.","PeriodicalId":12279,"journal":{"name":"Fire","volume":"47 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141818014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A compression ignition engine generates power by using the auto-ignition characteristics of fuel injected into the cylinder. Although it has high fuel efficiency, it discharges a lot of exhaust emissions such as NOX and PM. Therefore, there is much ongoing research aiming to reduce the exhaust emissions by using the technologies applied in this regard, such as PCCI, HCCI, etc. However, these methods still discharge large exhaust emissions. The RCCI method, which combines the spark ignition method and compression ignition method, is attracting attention. So, in this work, the objective of this study is to numerically investigate the effect of combustion phase according to the premixed ethanol ratio based on the same total heating value in-cylinder by changing the initial air composition on the formation and oxidation of exhaust emissions in the RCCI engine. The heating value of the premixed ethanol ratio varied from 0% to 40% based on the same total lower heating value in-cylinder in steps of 10%. It was assumed that the ethanol introduced into the cylinder through the premixing chamber was evaporated, and the initial air composition in the cylinder was changed and set. It was revealed that when the premixed ratio based on the same total lower heating value was increased, the introduced fuel amount into the crevice volume with advancing the start of energizing timing was decreased, which increased the peak cylinder pressure. In addition, the ignition delay was also longer due to the low cylinder temperature by the evaporation latent heat of the ethanol, which reduced the compression loss, so the IMEP value was increased. The rich equivalence ratio had a narrow distribution in the cylinder, which caused a reduction in cylinder temperature, so the NO formation amount was reduced. The ISCO value increased the increase in premixed ethanol ratio based on the same total lower heating value in-cylinder because the flame propagation of ethanol by combustion of diesel did not work well, and the CO formed by combustion was slowly oxidized due to the cylinder’s low temperature as a result of the evaporation latent heat of ethanol. From these results, the optimal operating conditions for simultaneously reducing the exhaust emissions and improving the combustion performance were judged such that the start of energizing timing was BTDC 23 deg, and the premixed ethanol ratio based on the same total lower heating value in-cylinder was 40%.
{"title":"The Effect of Combustion Phase According to the Premixed Ethanol Ratio Based on the Same Total Lower Heating Value on the Formation and Oxidation of Exhaust Emissions in a Reactivity-Controlled Compression Ignition Engine","authors":"S. Min, Hyunkyu Suh","doi":"10.3390/fire7070258","DOIUrl":"https://doi.org/10.3390/fire7070258","url":null,"abstract":"A compression ignition engine generates power by using the auto-ignition characteristics of fuel injected into the cylinder. Although it has high fuel efficiency, it discharges a lot of exhaust emissions such as NOX and PM. Therefore, there is much ongoing research aiming to reduce the exhaust emissions by using the technologies applied in this regard, such as PCCI, HCCI, etc. However, these methods still discharge large exhaust emissions. The RCCI method, which combines the spark ignition method and compression ignition method, is attracting attention. So, in this work, the objective of this study is to numerically investigate the effect of combustion phase according to the premixed ethanol ratio based on the same total heating value in-cylinder by changing the initial air composition on the formation and oxidation of exhaust emissions in the RCCI engine. The heating value of the premixed ethanol ratio varied from 0% to 40% based on the same total lower heating value in-cylinder in steps of 10%. It was assumed that the ethanol introduced into the cylinder through the premixing chamber was evaporated, and the initial air composition in the cylinder was changed and set. It was revealed that when the premixed ratio based on the same total lower heating value was increased, the introduced fuel amount into the crevice volume with advancing the start of energizing timing was decreased, which increased the peak cylinder pressure. In addition, the ignition delay was also longer due to the low cylinder temperature by the evaporation latent heat of the ethanol, which reduced the compression loss, so the IMEP value was increased. The rich equivalence ratio had a narrow distribution in the cylinder, which caused a reduction in cylinder temperature, so the NO formation amount was reduced. The ISCO value increased the increase in premixed ethanol ratio based on the same total lower heating value in-cylinder because the flame propagation of ethanol by combustion of diesel did not work well, and the CO formed by combustion was slowly oxidized due to the cylinder’s low temperature as a result of the evaporation latent heat of ethanol. From these results, the optimal operating conditions for simultaneously reducing the exhaust emissions and improving the combustion performance were judged such that the start of energizing timing was BTDC 23 deg, and the premixed ethanol ratio based on the same total lower heating value in-cylinder was 40%.","PeriodicalId":12279,"journal":{"name":"Fire","volume":"124 25","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141820778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Given the increasingly severe global fires, the accurate detection of small and fragmented cropland fires has been a significant challenge. The use of medium-resolution satellite data can enhance detection accuracy; however, key challenges in this approach include accurately capturing the annual and interannual variations of burning characteristics and identifying outliers within the time series of these changes. In this study, we focus on a typical crop-straw burning area in Henan Province, located on the North China Plain. We develop an automated burned-area detection algorithm based on near-infrared and short-wave infrared data from Landsat 5 imagery. Our method integrates time-series outlier analysis using filtering and automatic iterative algorithms to determine the optimal threshold for detecting burned areas. Our results demonstrate the effectiveness of using preceding time-series and seasonal time-series analysis to differentiate fire-related changes from seasonal and non-seasonal influences on vegetation. Optimal threshold validation results reveal that the automatic threshold method is efficient and feasible with an overall accuracy exceeding 93%. The resulting burned-area map achieves a total accuracy of 93.25%, far surpassing the 76.5% detection accuracy of the MCD64A1 fire product, thereby highlighting the efficacy of our algorithm. In conclusion, our algorithm is suitable for detecting burned areas in large-scale farmland settings and provides valuable information for the development of future detection algorithms.
{"title":"An Automated Cropland Burned-Area Detection Algorithm Based on Landsat Time Series Coupled with Optimized Outliers and Thresholds","authors":"Sumei Zhang, Huijuan Li, Hongmei Zhao","doi":"10.3390/fire7070257","DOIUrl":"https://doi.org/10.3390/fire7070257","url":null,"abstract":"Given the increasingly severe global fires, the accurate detection of small and fragmented cropland fires has been a significant challenge. The use of medium-resolution satellite data can enhance detection accuracy; however, key challenges in this approach include accurately capturing the annual and interannual variations of burning characteristics and identifying outliers within the time series of these changes. In this study, we focus on a typical crop-straw burning area in Henan Province, located on the North China Plain. We develop an automated burned-area detection algorithm based on near-infrared and short-wave infrared data from Landsat 5 imagery. Our method integrates time-series outlier analysis using filtering and automatic iterative algorithms to determine the optimal threshold for detecting burned areas. Our results demonstrate the effectiveness of using preceding time-series and seasonal time-series analysis to differentiate fire-related changes from seasonal and non-seasonal influences on vegetation. Optimal threshold validation results reveal that the automatic threshold method is efficient and feasible with an overall accuracy exceeding 93%. The resulting burned-area map achieves a total accuracy of 93.25%, far surpassing the 76.5% detection accuracy of the MCD64A1 fire product, thereby highlighting the efficacy of our algorithm. In conclusion, our algorithm is suitable for detecting burned areas in large-scale farmland settings and provides valuable information for the development of future detection algorithms.","PeriodicalId":12279,"journal":{"name":"Fire","volume":" 47","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141824962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigates the applicability of eco-friendly silicone materials with improved flame retardancy as interior materials for Korean urban railway vehicles, focusing on developing nonslip pads for seats made of non-combustible materials. Fire safety standards vary worldwide, necessitating country-specific testing and analysis. For application to the interior of railway vehicles in Korea, technical standards for the flame-retardant performance of railway vehicles were evaluated, and nonslip pads for seats were tested by comparing two types of flame-retardant silicone. In addition to fire property testing on a specimen basis, experimental verification was performed on a full chair assembly including silicone pads. Passenger comfort testing through pressure measurements was also conducted alongside fire safety performance testing The actual fire test showed that the maximum average heat release rate value was about 20% lower than the standard’s upper limit. Using flame-retardant silicone pads enhances fire safety and passenger comfort, satisfactorily meeting the required performance standards for Korean railway vehicles.
{"title":"Flame Resistance Performance of Silicone Pad for Application in Railway Industry","authors":"Hong-Lae Jang, Tae-Soon Kwon, Seok-Won Kang, Kyungwho Choi","doi":"10.3390/fire7070255","DOIUrl":"https://doi.org/10.3390/fire7070255","url":null,"abstract":"This study investigates the applicability of eco-friendly silicone materials with improved flame retardancy as interior materials for Korean urban railway vehicles, focusing on developing nonslip pads for seats made of non-combustible materials. Fire safety standards vary worldwide, necessitating country-specific testing and analysis. For application to the interior of railway vehicles in Korea, technical standards for the flame-retardant performance of railway vehicles were evaluated, and nonslip pads for seats were tested by comparing two types of flame-retardant silicone. In addition to fire property testing on a specimen basis, experimental verification was performed on a full chair assembly including silicone pads. Passenger comfort testing through pressure measurements was also conducted alongside fire safety performance testing The actual fire test showed that the maximum average heat release rate value was about 20% lower than the standard’s upper limit. Using flame-retardant silicone pads enhances fire safety and passenger comfort, satisfactorily meeting the required performance standards for Korean railway vehicles.","PeriodicalId":12279,"journal":{"name":"Fire","volume":" 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141827243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：