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Post-fire recovery of Puya raimondii, vegetation and birds in the puna of Huascarán National Park, Perú

Journal of Mountain Science 2024年第1期21卷 20-32页

作者： Mery L.SUNI Giovana P.VADILLO César ARANA Enoc JARA-PENA Letty SALINAS M.Estela PONCE Paul M.RAMSAY Plant Physiology Laboratory Faculty of Biological SciencesUniversidad Nacional Mayor de San MarcosLima 15081Peru Natural History Museum Universidad Nacional Mayor de San MarcosLima 15072Peru Applied Phytology Laboratory Faculty of Biological SciencesUniversidad Nacional Mayor de San MarcosLima 15081Peru Department of Statistics Faculty of Mathematical SciencesUniversidad Nacional Mayor de San MarcosLima 15081Peru Department of Chemical and Biological Sciences Universidad de las Américas PueblaSan Andrés Cholula CP Cholula CP 72810Mexico

A large fire of 233 ha in Huascarán National Park in Peru provided an opportunity to compare plant and bird responses in burned and nearby unburned zones of the puna. Heights and live diameters of flagship Puya raimondii rosettes(assigned to four broad developmental phases), plant communities(66 species in 24 families and nine growth forms) and bird communities(77 species in six trophic guilds) were monitored after the fire. Although no mortality was observed, Puya raimondii plants were affected by the fire, losing approximately 60% of their photosynthetic area across all developmental phases, but recovered quickly during the first two years after fire. The comparison of Puya rosette recovery after fire was complicated by the changes in live rosette diameter for unburned plants, which showed plasticity of photosynthetic area linked to seasonal and annual fluctuations in precipitation in this relatively dry environment(decreased by 26% for mature adult plants over the study period). Fire caused an immediate change in the density, biomass and composition of vegetation. Although the species present remained similar, their abundances changed significantly immediately after the fire, with notable reductions in dominant tussock grasses. This provided opportunities for other plants, resulting in higher postfire diversity of plant species, genera, families and growth forms. In turn, the changes in vegetation after fire affected the composition of birds according to their trophic guild. Granivores largely disappeared,generalists were mostly unaffected, and other guilds showed a more complex response. As the vegetation recovered, most displaced birds returned within approximately one year.

关键词： burning Plant biomass Trophic guilds Andes Giant rosette plants

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Analysis of monitoring results of skeletal fluorosis in coal-burning type endemic fluorosis areas in Guizhou Province

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China Medical Abstracts(Internal Medicine) 2024年第1期41卷 21-21页

作者：高静 Dept Epidemiol Instit Endem DisGuizhou Dis Contr&Prev CenterGuiyang 550004

Objective To analyze the monitoring results of skeletal fluorosis in coal-burning type endemic fluorosis areas in Guizhou Province,and evaluate the effectiveness of comprehensive treatment of coal-burning type endemic... 详细信息

关键词： Guizhou burning skeletal

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Effects of phase change material(PCM)-based nanocomposite additives on thermal decomposition and burning characteristic of high energy propellants containing RDX

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Defence Technology（防务技术） 2022年第4期18卷 557-566页

作者： En-fa Fu Na Sun Zheng-gang Xiao Key Laboratory of Special Energy Materials Ministry of Education School of Chemical Engineering Nanjing University of Science and Technology

A kind of phase change material(PCM)-based nanocomposite was prepared and added into high energy propellants containing RDX as additives to investigate its effect on thermal decomposition and burning characteristic of high energy propellants.The effect of PCM-based nanocomposites on thermal decomposition of high energy propellants is investigated by TG/DSC-FTIR-MS technology.Due to the delayed protection effect(PCM-based nanocomposites can absorb lots of heat at the range of certain temperature when it undergoes structure change or phase transitions)of PCM-based nanocomposites under the thermal decomposition condition,the thermal stability of high energy propellants modified with PCMbased nanocomposites is improved.At the same time,the concentration of N2,NO2,H2O and CO_(2)is increased during thermal decomposition of high energy propellants whereas NO and CO is decreased.The burning gaseous products and burning characteristic of high energy propellants are studied by the combination of closed bomb test and Fourier transform infrared spectrum.The main burning gaseous products are N2,CO_(2),CO,H2O,CH4,etc.After the high energy propellant modified with PCM-based nanocomposites,the concentration of CH4is increased while CO,CO_(2) and H2O is decreased under the high-pressure burning condition.The progressivity factor of high energy propellants is increased by22.2%compared with the control sample while the maximum pressure is merely decreased 1.25%after the addition of the PCM-based nanocomposite,thus PCM-based nanocomposites can be used to adjust the burning process and improve the burning progressivity of high energy propellants.This study is expected to boost the practical application of PCM-based nanocomposite to the propellant formulation and effectively control the burning characteristic of high energy propellants.

关键词： Phase change material Propellants Nanocomposite Thermal decomposition burning

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Natural regeneration responses to thinning and burning treatments in ponderosa pine forests and implications for restoration

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Journal of Forestry Research 2022年第3期33卷 741-753页

作者： Tzeidle N.Wasserman Amy E.M.Waltz John Paul Roccaforte Judith D.Springer Joseph E.Crouse Ecological Restoration Institute Northern Arizona UniversityP.O.Box 15017FlagstaffAZ86011-5017USA

Understanding naturally occurring pine regeneration dynamics in response to thinning and burning treatments is necessary not only to measure the longevity of the restoration or fuels treatment,but also to assess how well regeneration meets forest sustainability guidelines and whether natural regeneration is sufficient for maintaining a sustainable forest structure and composition.A synthesis review was carried out on the effects of mechanical thinning and prescribed burn treatments on natural pine regeneration response in frequent-fire ponderosa pine forests across the western United States.The focus was on site-specific variability in pine regeneration dynamics,temporal trends in regeneration presence and abundance,and response to treatment as described in the current literature using 29 studies that met our evidence-based review protocols.Data showed that the effects of thinning and burning treatments on regeneration depended on time since treatment.Mechanical thinning,prescribed burning,and thinning plus burn treatments all increased seedling density,but there was high variability among sites and studies.There were mixed results in the short-term(20 years)concluded that stands can return to pre-treatment densities in terms of total trees per hectare and forest floor duff levels when there are no maintenance treatments applied.Several studies showed the average ponderosa pine seedling presence,survival and growth found in today’s forests to be at a high density;this combined with missed fire cycles could contribute to future fire risk and reduce the efficacy of maintaining fuel reduction goals.

关键词： Regeneration Ponderosa pine Frequent-fire Treatments Thinning burning

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Characteristics,evolution,and regional differences of biomass burning particles in the Sichuan Basin,China

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Journal of Environmental Sciences 2020年第3期32卷 35-46页

作者： Jinqi Luo Junke Zhang Xiaojuan Huang Qin Liu Bin Luo Wei Zhang Zhihan Rao Yangchun Yu Faculty of Geosciences and Environmental Engineering Southwest Jiaotong UniversityChengdu 611756China Plateau Atmosphere and Environment Key Laboratory of Sichuan Province School of Atmospheric SciencesChengdu University of Information TechnologyChengdu 610225China Sichuan Environmental Monitoring Center Chengdu 610074China Shandong Academy for Environmental Planning Jinan 250101China

The Sichuan Basin has experienced serious air pollution from fine particulate matter(PM2.5) in the past few years with biomass burning has been identified as a major source of PM2.5 in this region.We used single particle aerosol mass spectrometer to investigate the characteristics of biomass burning particles in three interacting cities representing different types of urban environment in the Sichuan Basin.A total of 739,794,279,610,and380,636 biomass burning particles were detected at Ya’an,Guang’an,and Chengdu,which represented 42%,69%,and 61%,respectively,of the total number of particles.We analyzed the chemical composition,transportation,and evolution of biomass burning particles.The contribution of K-elemental carbon and K-secondary inorganic particles was highest in Ya’an(36%) and Guang’an(47%),respectively,reflecting the important role of fresh biomass burning particles and long-distance transport in these two cities.Air masses originating from different directions corresponded to different levels of PM2.5 and the contributions of polluted clusters increased significantly on polluted days.Fresh and secondary inorganic biomass burning particles increased pollution at Ya’an and Guang’an,respectively,but dominated different stages of pollution in Chengdu.K-nitrate particles were formed by photochemical reactions,whereas K-sulfate particles were formed by both photochemical and liquid-phase reactions.Investigation of the degree of particle aging showed that there were more fresh particles at Ya’an and more aged particles at Guang’an.These results are useful in helping our understanding of the characteristics of biomass burning particles and evaluating their role in PM2.5 pollution in the Sichuan Basin.

关键词： Single particles Biomass burning particles Evolution Regional differences Sichuan basin

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burning rate and other characteristics of strontium titanate （SrTiO3） supplemented AP/HTPB/Al composite propellants

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Defence Technology（防务技术） 2019年第3期15卷 313-318页

作者： Sunil Jain Garima Gupta Dhirendra R. Kshirsagar Vrushali H. Khire Balasubramanian Kandasubramanian HEMRL Sutarwadi Pune India a DIAT Girinagar Pune India

In a quest of search for a new burning rate modifier for composite propellant, strontium titanate (SrTiO3), a perovskite oxide has been chosen for evaluation in a composite propellant formulation based on its other catalytic applications. Initially, SrTiO3 was characterized for particle size, morphology and material/ phase identification (using XRD). By varying SrTiO3 content in a standard composite propellant, different compositions were prepared and their performance and processing parameters like the end of mix (EOM) viscosity, mechanical properties, density, burning rate, pressure exponent (n-value), etc. were measured. The results reveal that 2% SrTiO3 causes more than 12% enhancement in propellant burning rate (at 70 ksc pressure) in comparison to the standard propellant composition. The pressure exponent also increases to 0.46, whereas the standard composition was having its value as 0.35.

关键词： Strontium titanate Ammonium perchlorate Composite propellant burning rate

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Evolution in physiochemical and cloud condensation nuclei activation properties of crop residue burning particles during photochemical aging

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Journal of Environmental Sciences 2019年第3期31卷 43-53页

作者： Yan Ma Chao Chen Junfeng Wang Youling Jiang Zewen Zheng Hui Chen Jun Zheng Collaborative Innovation Center of Atmospheric Environment and Equipment Technology Nanjing University of Information Science and Technology Harvard-NUIST Joint Laboratory for Air Quality and Climate (JLAQC) Nanjing University of Information Science and Technology NUIST Reading Academy Nanjing University of Information Science and Technology

As a main form of biomass burning in agricultural countries, crop residue burning is a significant source of atmospheric fine particles. In this study, the aging of particles emitted from the burning of four major crop residues in China was investigated in a smog chamber.The particle size distribution, chemical composition and cloud condensation nuclei(CCN)activity were simultaneously measured. The properties of crop residue burning particles varied substantially among different fuel types. During aging, the particle size and mass concentration increased substantially, suggesting condensational growth by formation of secondary aerosols. The particle composition was dominated by organics. Aging resulted in considerable enhancement of organics and inorganics, with enhancement ratios of 1.24–1.44 and 1.33–1.76 respectively, as well as a continuous increase in the oxidation level of organics. Elevated CCN activity was observed during aging, with the hygroscopicity parameter κ varying from 0.16 to 0.34 for fresh particles and 0.19 to 0.40 for aged particles.Based on the volume mixing rule, the hygroscopicity parameter of organic components(κorg) was derived. κorgexhibited an increasing tendency with aging, which was generally consistent with the tendency of the O:C ratio, indicating that the oxidation level was related to the hygroscopicity and CCN activity of organic aerosols from crop residue burning. Our results indicated that photochemical aging could significantly impact the CCN activation of crop burning aerosols, not only by the production of secondary aerosols, but also by enhancing the hygroscopicity of organic components, thereby contributing to the aerosol indirect climate forcing.

关键词： Crop residue burning Aging Cloud condensation nuclei activity Hygroscopicity Organic aerosol

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Species-specific Response of Photosynthesis to burning and Nitrogen Fertilization

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Journal of Integrative Plant Biology 2008年第5期50卷 565-574页

作者： Yanfang Zhang Shuli Niu Wenhua Xu Yi Han State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing 100093 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

The present study was conducted to examine photosynthetic characteristics of three dominant grass species （Agropyron cristatum, Leymus chinensis, and Cleistogenes squarrosa） and their responses to burning and nitrogen fertilization in a semiarid grassland in northern China. Photosynthetic rate （Pn）, stomatal conductance （gs）, and water use efficiency （WUE） showed strong temporal variability over the growing season. C. squarrosa showed a significantly higher Pn and WUE than A. cristatum and L. chinensis. burning stimulated Pn of A. cristatum and L. chinensis by 24-59% （P 〈 0.05） in the early growing season, but not during other time periods. Light-saturated photosynthetic rate （Pmax） in A. cristatum and the maximum apparent quantum yield （Фmax） in A. cristatum and L. chinensis were significantly enhanced by burning （16-67%） in both the fertilized and unfertilized plots. The main effect of burning on Pn, Pmax and Фmax was not significant in C. squarrosa. The burning-induced changes in soil moisture could explain 51% （P= 0.01） of the burning-induced changes in Pn of the three species. All three species showed positive responses to N fertilization in terms of Pn, Pmax, and Фmax. The stimulation of Pn under N fertilization was mainly observed in the early growing season when the soil extractable N content was significantly higher in the fertilized plots. The N fertilization-induced changes in soil extractable N content could explain 66% （P = 0.001） of the changes in Pn under N fertilization. The photosynthetic responses of the three species indicate that burning and N fertilization will potentially change the community structure and ecosystem productivity in the semiarid grasslands of northern China.

关键词： Agropyron cristatum burning Cleistogenes squarrosa Leymus chinensis nitrogen fertilization photosynthesis

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Effects of Plasticizers,Antioxidants and burning Rate Modifiers on Aging Performance of the HTPB/HMDI Composite Solid Propellant

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含能材料 2019年第1期27卷 21-27,90页

作者： Ahmed M Enew Ehab Abadir Sahar Elmarsafy Karim K Elsharkawy Chemical Department Faculty of EngineeringCairo University School of Chemistry and Environment Beijing University of Aeronautics and Astronautics

The effects of plasticizers,antioxidants and burning rate modifiers on the aging performance of the composite solid propellant based on hydroxyl-terminated polybutadiene(HTPB)/hexamethylene diisocyanate(HMDI)were explored by apply-ing an accelerated aging program for 90 day at 70 ℃. The HTPB propellant matrix with the diisooctyl sebacate(DOS)as plasti-cizers and diisooctyl azelate(DOZ), antioxidants as N,N ′-Diphenyl-p-phenylenediamine(AO) and 2,2′-methylenebis(4-methyl-6-tert-butylphenol)(cyanox 2246)and burning rate modifiers as barium ferrite(BF),copper chromites(CC)and fer-ric oxide(FO)were varied. Results show that sample(S1)which based on DOS decreases the stress value and increases the strain value which considered to be an excellent start for aging program. Sample(S3)containing AO presents the higher resis-tance to oxidation showing the better performance that reflects on increasing the shelf life of the composite solid propellant mo-tor. Sample(S5)which based on BF enhances the ballistic performance among over the other tested two samples. The accelerat-ed aging program allowed us to estimate the motor in-service lifetime.

关键词： polybutadiene(HTPB)/hexamethylene diisocyanate(HMDI)composite solid propellant plasticizers antioxidants burning rate modifiers aging program

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Inventory of Atmospheric Pollutant Emissions from burning of Crop Residues in China Based on Satellite-retrieved Farmland Data

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Chinese Geographical Science 2020年第2期30卷 266-278页

作者： LI Ruimin CHEN Weiwei ZHAO Hongmei WU Xuewei ZHANG Mengduo TONG Daniel Q XIU Aijun Key Laboratory of Wetland Ecology and Environment Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun 130102China University of Chinese Academy of Sciences Beijing 100049China Center for Spatial Information Science and Systems George Mason UniversityFairfax VA 22030USA Cooperative Institute for Climate&Satellites University of MarylandMD 20740USA

The burning of crop residues emits large quantities of atmospheric aerosols.Published studies have developed inventories of emissions from crop residue burning based on statistical data.In contrast,this study used satellite-retrieved land-cover data(1 km×1 km)as activity data to compile an inventory of atmospheric pollutants emitted from the burning of crop residues in China in 2015.The emissions of PM10,PM2.5,VOCs,NOx,SO2,CO,and NH3 from burning crop straw on nonirrigated farmland in China in 2015 were 610.5,598.4,584.4,230.6,35.4,3329.3,and 36.1 Gg(1 Gg=109 g),respectively;the corresponding emissions from burning paddy rice residues were 234.1,229.7,342.3,57.5,57.5,1122.1,and 21.5 Gg,respectively.The emissions from crop residue burning showed large spatial and temporal variations.The emissions of particulate matter and gaseous pollutants from crop residue burning in nonirrigated farmland were highest in east China,particularly in Shandong,Henan,Anhui,and Sichuan provinces.Emissions from burning paddy rice residue were highest in east and central China,with particularly high levels in Shandong,Jiangsu,Zhejiang,and Hunan provinces.The monthly variations in atmospheric pollutant emissions were similar among different regions,with the highest levels observed in October in north,northeast,northwest,east,and southwest China and in June and July in central and south China.The developed inventory of emissions from crop residue burning is expected to help improve air quality models by providing high-resolution spatial and temporal data.

关键词： crop residue burning land-cover data particular matter(PM) gaseous pollutants emission inventory

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