The species-area relationship （SAR） is one of the most fundamental concepts in community ecology and is helpful for biodiversity conservation. However, few studies have systematically addressed this topic for differ...The species-area relationship （SAR） is one of the most fundamental concepts in community ecology and is helpful for biodiversity conservation. However, few studies have systematically addressed this topic for different alpine grassland types on the Tibetan Plateau, China. We explored whether the plant composition of different functional groups affects the manner in which species richness inereases with increasing area at scales ≤ 1.0 m^2. We also compared species richness （S） within and across forbs, legumes, sedges and grasses, with sampling subplot area （A） increasing from 0.0625 m^2 to 1.0 m^2 between alpine meadow and steppe communities. We applied a logarithmic function （S = b0 ＋ b1 ln A） to determine the slope and intercept of SAR curves within and across functional groups. The results showed that the logarithmic relationship holds true between species richness and sampling area at these small scales. Both the intercept and slope of the logarithmic forbs-area curves are significantly higher than those for the three other functional groups （P 〈 0.05）. Forb accounts for about 91.9 % of the variation in the intercept and 75.0% of the variation in the slope of the SAR curve when all functional groups＇ data were pooled together. Our results indicated that the different SAR patterns should be linked with species dispersal capabilities, environmental filtering, and life form composition within alpine grassland communities. Further studies on the relationship between species diversity and ecosystem functions should specify the differential responses of different functional groups to variations in climate and anthropogenic disturbances.展开更多
To study the adsorption properties of organic functional groups in plant fibres and identify a highly efficient and affordable adsorbent for radioactive wastewater treatment,natural bamboo fibre(NBF)samples were prepa...To study the adsorption properties of organic functional groups in plant fibres and identify a highly efficient and affordable adsorbent for radioactive wastewater treatment,natural bamboo fibre(NBF)samples were prepared,and the adsorption properties of Eu(Ⅲ)on NBFs were studied under given experimental conditions.The effects of the pH,solid-to-liquid ratio,background ions,humic acid,contact time,and temperature on the adsorption behaviour of Eu(Ⅲ)on NBFs were investigated.Adsorption was greatly influenced by pH,and the adsorption curves presented two inflection points at pH≈7 and pH≈11.Moreover,while the ionic strength presented a negative effect at pH<7,the high ionic strength favoured adsorption at pH>7.During adsorption on NBFs,the–OH,C–H,O–H,C–O,and C=O were the main adsorption groups.Hydrolysis occurring on the NBF surface caused the adsorption process to become increasingly difficult at pH>7.The maximum adsorption capacity of NBFs was 147.6 mg/g at 308 K,and the adsorption could be described using the pseudo-second-order kinetic model.The adsorption of Eu(Ⅲ)on NBFs was a spontaneous and endothermic process according to the thermodynamic parameters of the process,and the adsorption thermodynamics could be well described using the Freundlich adsorption model.Therefore,NBFs were determined to be an efficient,inexpensive,and easily disposable sewage treatment material.展开更多
Fiber reinforced polypropylene has been widely accepted as material for structural and engineering applications in recent years.Jute,Banana fibers etc.are the most common low cost,versatile,renewable and abundantly av...Fiber reinforced polypropylene has been widely accepted as material for structural and engineering applications in recent years.Jute,Banana fibers etc.are the most common low cost,versatile,renewable and abundantly available natural fibers which have biodegradable properties.All these fibers are versatile,renewable and most common agro based fibers that have enormous aspect due to their potentiality in composite manufacture.In comparison to other artificial fibers there are many advantages of natural fibers due to everyday applications such as,paperweight,suitcases,lampshades,helmets,and shower and bath units.Untreated and alkali treated banana fiber reinforced with Polypropylene matrix composite were fabricated with 10-25%loading of fiber by weight and were fabricated as Polypropylene Banana Composite(PPBC).Using melt mixing hot press molding technique these biodegradable composites were prepared.Different characteristics like morphologies and micro structural analysis of the composites were studied by Scanning electron microscope(SEM)and infrared spectroscopy instrument(IR).Due to the concept of group vibration infrared spectroscopy has the extensive application.Any kind of structural change such as addition or substitution of groups or atoms in a molecule may affect the relative mode of vibration of the group.This causes change in IR spectral band position,change in relative intensities and appearance of new bands and disappearance of any band and splitting of a single band into two or more bands.To increase the utility of fiber infrared spectroscopy can also be used.It deals with the interaction of infrared light with matter.The former can indicate the presence of functional groups qualitatively and the latter can provide a semi quantitative measure of their concentrations.On the other hand Electron Microscopy is most widely used to obtain information regarding the morphology of fiber surfaces,especially SEM(Scanning Electron Microscopy).Using SEM,it is easy to determine the differences of fiber surface topography after and before treatment,and hence the formation of fiber polymer composites.Fiber deboning was also observed for untreated and treated fiber pp matrix composite.The SEM can have a magnification range from a few times to several hundred thousand times.展开更多
Fire is a natural disturbance occurring every few years in many grasslands ecosystems. However, since European colonization, fire has been highly reduced or even suppressed in Argentinean grasslands, fostering ignitab...Fire is a natural disturbance occurring every few years in many grasslands ecosystems. However, since European colonization, fire has been highly reduced or even suppressed in Argentinean grasslands, fostering ignitable material accumulation. This has led to occasional catastrophic controldemanding fire events, extended for larger areas. The aims of this work are to study vegetation recovery and change after a non-natural fire event in mountain grasslands. The study area is located in the Ventania mountain system, mid-eastern Argentina. We studied vegetation recovery after fire(January 2014) in two different communities: grass-steppes(grasslands) and shrub-steppes(open low shrublands). We measured vegetation cover, species richness and bare ground percentage in burned and unburned areas 1, 4, 8, 11 and 23 months after fire. Vegetation surveys were also performed at the end of the growing season(December) 11 and 23 months after fire. Data were analyzed using regression analysis, ANOVA and multivariate analysis(NMS, PERMANOVA). Both communities increased their vegetation cover at the same rate, without differences between burned and unburned areas after two years. Species richness was higher in shrublands and their recovery was alsofaster than in grasslands. Considering functional composition, besides transient changes during the first year after fire, there were no differences in abundance of different functional vegetation groups two years after fire. At the same time, shrublands showed no differences in species composition, while grasslands had a different species composition in burned and unburned plots. Also, burned grassland showed a higher species richness than unburned grassland. Data shown mountain vegetation in Pampas grassland is adapted to fire, recovering cover and richness rapidly after fire and thus reducing soil erosion risks. Vegetation in mountain Pampas seems to be well adapted to fire, but in grasslands species composition has changed due to fire. Nonetheless, these changes seem to be not permanent since prefire species are still present in the area.展开更多
With growing environmental concerns and the depletion of oil reserves,the need to replace synthetic fibres with sustainable alternatives in composite materials has become increasingly urgent.This study investigates th...With growing environmental concerns and the depletion of oil reserves,the need to replace synthetic fibres with sustainable alternatives in composite materials has become increasingly urgent.This study investigates the potential of Leptadenia pyrotechnica fibre as a sustainable reinforcement material in hybrid composites alongside E-glass fibres.The primary objectives are to assess these hybrid composites’mechanical properties,structural integrity,and performance.To achieve this,Scanning Electron Microscopy(SEM)and Fourier Transform Infrared Spectroscopy(FTIR)were employed to analyze the microstructure and chemical composition of the composites.At the same time,mechanical testing focused on properties such as flexural strength and compression strength.Inter-laminar failure analysis evaluated how well the fibres bonded within the composite structure.The results demonstrate that Leptadenia pyrotechnica fibres significantly enhance flexural strength and offer mechanical properties suitable for diverse industrial applications.This indicates their potential as a sustainable alternative to traditional natural fibres.The findings suggest that incorporating Leptadenia pyrotechnica in hybrid composites could lead to the development of more environmentally friendly and durable materials.This work highlights the significance of using sustainable,naturally sourced fibres in composite materials,offering a promising path for further exploration in industrial applications.展开更多
基金supported by the Chinese Academy of Sciences (Grant Nos.XDB03030401,KZCXZ-XB3-08)the State Scholarship Fund of the China Scholarship Council (Grant No.201400260118)the International Postdoctoral Exchange Fellowship Program 2014 by the Office of China Postdoctoral Council (Grant No.20140041)
文摘The species-area relationship （SAR） is one of the most fundamental concepts in community ecology and is helpful for biodiversity conservation. However, few studies have systematically addressed this topic for different alpine grassland types on the Tibetan Plateau, China. We explored whether the plant composition of different functional groups affects the manner in which species richness inereases with increasing area at scales ≤ 1.0 m^2. We also compared species richness （S） within and across forbs, legumes, sedges and grasses, with sampling subplot area （A） increasing from 0.0625 m^2 to 1.0 m^2 between alpine meadow and steppe communities. We applied a logarithmic function （S = b0 ＋ b1 ln A） to determine the slope and intercept of SAR curves within and across functional groups. The results showed that the logarithmic relationship holds true between species richness and sampling area at these small scales. Both the intercept and slope of the logarithmic forbs-area curves are significantly higher than those for the three other functional groups （P 〈 0.05）. Forb accounts for about 91.9 % of the variation in the intercept and 75.0% of the variation in the slope of the SAR curve when all functional groups＇ data were pooled together. Our results indicated that the different SAR patterns should be linked with species dispersal capabilities, environmental filtering, and life form composition within alpine grassland communities. Further studies on the relationship between species diversity and ecosystem functions should specify the differential responses of different functional groups to variations in climate and anthropogenic disturbances.
基金supported by the National Natural Science Foundation of China(No.21561001)the Natural Science Foundation of Jiangxi Province,China(No.20161BAB203100)
文摘To study the adsorption properties of organic functional groups in plant fibres and identify a highly efficient and affordable adsorbent for radioactive wastewater treatment,natural bamboo fibre(NBF)samples were prepared,and the adsorption properties of Eu(Ⅲ)on NBFs were studied under given experimental conditions.The effects of the pH,solid-to-liquid ratio,background ions,humic acid,contact time,and temperature on the adsorption behaviour of Eu(Ⅲ)on NBFs were investigated.Adsorption was greatly influenced by pH,and the adsorption curves presented two inflection points at pH≈7 and pH≈11.Moreover,while the ionic strength presented a negative effect at pH<7,the high ionic strength favoured adsorption at pH>7.During adsorption on NBFs,the–OH,C–H,O–H,C–O,and C=O were the main adsorption groups.Hydrolysis occurring on the NBF surface caused the adsorption process to become increasingly difficult at pH>7.The maximum adsorption capacity of NBFs was 147.6 mg/g at 308 K,and the adsorption could be described using the pseudo-second-order kinetic model.The adsorption of Eu(Ⅲ)on NBFs was a spontaneous and endothermic process according to the thermodynamic parameters of the process,and the adsorption thermodynamics could be well described using the Freundlich adsorption model.Therefore,NBFs were determined to be an efficient,inexpensive,and easily disposable sewage treatment material.
文摘Fiber reinforced polypropylene has been widely accepted as material for structural and engineering applications in recent years.Jute,Banana fibers etc.are the most common low cost,versatile,renewable and abundantly available natural fibers which have biodegradable properties.All these fibers are versatile,renewable and most common agro based fibers that have enormous aspect due to their potentiality in composite manufacture.In comparison to other artificial fibers there are many advantages of natural fibers due to everyday applications such as,paperweight,suitcases,lampshades,helmets,and shower and bath units.Untreated and alkali treated banana fiber reinforced with Polypropylene matrix composite were fabricated with 10-25%loading of fiber by weight and were fabricated as Polypropylene Banana Composite(PPBC).Using melt mixing hot press molding technique these biodegradable composites were prepared.Different characteristics like morphologies and micro structural analysis of the composites were studied by Scanning electron microscope(SEM)and infrared spectroscopy instrument(IR).Due to the concept of group vibration infrared spectroscopy has the extensive application.Any kind of structural change such as addition or substitution of groups or atoms in a molecule may affect the relative mode of vibration of the group.This causes change in IR spectral band position,change in relative intensities and appearance of new bands and disappearance of any band and splitting of a single band into two or more bands.To increase the utility of fiber infrared spectroscopy can also be used.It deals with the interaction of infrared light with matter.The former can indicate the presence of functional groups qualitatively and the latter can provide a semi quantitative measure of their concentrations.On the other hand Electron Microscopy is most widely used to obtain information regarding the morphology of fiber surfaces,especially SEM(Scanning Electron Microscopy).Using SEM,it is easy to determine the differences of fiber surface topography after and before treatment,and hence the formation of fiber polymer composites.Fiber deboning was also observed for untreated and treated fiber pp matrix composite.The SEM can have a magnification range from a few times to several hundred thousand times.
基金supported by the ANPCyT under grant PICT 2014-0865CONICET and Universidad Nacional del Sur from Argentina
文摘Fire is a natural disturbance occurring every few years in many grasslands ecosystems. However, since European colonization, fire has been highly reduced or even suppressed in Argentinean grasslands, fostering ignitable material accumulation. This has led to occasional catastrophic controldemanding fire events, extended for larger areas. The aims of this work are to study vegetation recovery and change after a non-natural fire event in mountain grasslands. The study area is located in the Ventania mountain system, mid-eastern Argentina. We studied vegetation recovery after fire(January 2014) in two different communities: grass-steppes(grasslands) and shrub-steppes(open low shrublands). We measured vegetation cover, species richness and bare ground percentage in burned and unburned areas 1, 4, 8, 11 and 23 months after fire. Vegetation surveys were also performed at the end of the growing season(December) 11 and 23 months after fire. Data were analyzed using regression analysis, ANOVA and multivariate analysis(NMS, PERMANOVA). Both communities increased their vegetation cover at the same rate, without differences between burned and unburned areas after two years. Species richness was higher in shrublands and their recovery was alsofaster than in grasslands. Considering functional composition, besides transient changes during the first year after fire, there were no differences in abundance of different functional vegetation groups two years after fire. At the same time, shrublands showed no differences in species composition, while grasslands had a different species composition in burned and unburned plots. Also, burned grassland showed a higher species richness than unburned grassland. Data shown mountain vegetation in Pampas grassland is adapted to fire, recovering cover and richness rapidly after fire and thus reducing soil erosion risks. Vegetation in mountain Pampas seems to be well adapted to fire, but in grasslands species composition has changed due to fire. Nonetheless, these changes seem to be not permanent since prefire species are still present in the area.
文摘With growing environmental concerns and the depletion of oil reserves,the need to replace synthetic fibres with sustainable alternatives in composite materials has become increasingly urgent.This study investigates the potential of Leptadenia pyrotechnica fibre as a sustainable reinforcement material in hybrid composites alongside E-glass fibres.The primary objectives are to assess these hybrid composites’mechanical properties,structural integrity,and performance.To achieve this,Scanning Electron Microscopy(SEM)and Fourier Transform Infrared Spectroscopy(FTIR)were employed to analyze the microstructure and chemical composition of the composites.At the same time,mechanical testing focused on properties such as flexural strength and compression strength.Inter-laminar failure analysis evaluated how well the fibres bonded within the composite structure.The results demonstrate that Leptadenia pyrotechnica fibres significantly enhance flexural strength and offer mechanical properties suitable for diverse industrial applications.This indicates their potential as a sustainable alternative to traditional natural fibres.The findings suggest that incorporating Leptadenia pyrotechnica in hybrid composites could lead to the development of more environmentally friendly and durable materials.This work highlights the significance of using sustainable,naturally sourced fibres in composite materials,offering a promising path for further exploration in industrial applications.
