Now one of the main cash crops in Côte d’Ivoire, the cashew tree feeds an entire industrial sector based on the processing of its fruit. This processing generates a large volume of waste, consisting of cashew nu...Now one of the main cash crops in Côte d’Ivoire, the cashew tree feeds an entire industrial sector based on the processing of its fruit. This processing generates a large volume of waste, consisting of cashew nutshells, the management of which poses environmental problems. With the aim of replacing charcoal and firewood with more environmentally friendly fuels, several studies are currently being carried out into the optimal use of cashew shells in fuel briquettes. To assess the environmental sustainability of these briquettes, this study calculates the environmental impacts associated with their life cycle, compares them with those of charcoal and firewood, and identifies the processes that contribute most to environmental pollution, with a view to improving them. Analysis of the results showed that cashew nutshell briquettes emit a range of pollutants over their life cycle that damage the environment and are responsible for the 7 impact categories considered: acidification, eutrophication, freshwater aquatic ecotoxicity, global warming, human toxicity, photochemical oxidation and terrestrial ecotoxicity potential. However, they are more environmentally friendly than charcoal and firewood for 5 impact categories: freshwater aquatic ecotoxicity, global warming, human toxicity, photochemical oxidation and terrestrial ecotoxicity potential. The 3 elementary processes, i.e. transport of biomass raw materials, production, and combustion of briquettes, emit pollutants that contribute most to the creation of environmental impact categories. The most relevant pollutants are nitrogen oxides (NOx), sulphur oxides (SOx) and particulate matter (PM).展开更多
The parameters of energy and power for nut rupturing play a key role in the design of shell-breaking equipment.However,currently,there is no scientifically accurate measuring method for these parameters.A mechanical n...The parameters of energy and power for nut rupturing play a key role in the design of shell-breaking equipment.However,currently,there is no scientifically accurate measuring method for these parameters.A mechanical nut testbed was developed to accurately measure the force,energy,and power and observe the generating process of nutshell cracking and breaking to reveal the shell-breaking mechanism.The system was tested with pecans and the results show that the testbed can effectively realize the determination of nuts performance and data acquisition and analysis.The methods and data can provide a theoretical guidance for the design and optimization of shell-breaking equipment and decrease kernel-breaking rate.展开更多
北京理工大学的刁文景老师为本栏目发来一稿。其译文相当不错,我们编者为其译文,添加了“评注”,点评翻译的难点以及原文的妙处。希望读者喜欢,而不至于认为“评注”是“蛇足”。文章的标题也存在一个英语成语:in anutshell。nutshell者...北京理工大学的刁文景老师为本栏目发来一稿。其译文相当不错,我们编者为其译文,添加了“评注”,点评翻译的难点以及原文的妙处。希望读者喜欢,而不至于认为“评注”是“蛇足”。文章的标题也存在一个英语成语:in anutshell。nutshell者,坚果壳也。一个坚果壳中能容纳多少东西呢?因此,in anutshell的含义猜想可知:简单地,简约地。人们在翻译这个英语成语时,常殚精竭虑,试图译出成语中的nutshell,如: Instead,to this quick-witted youth,the whole noble science of the law was Contained in a nutshell. 译文A:相反,对于这个机敏的年轻人来说,法律这门高贵科学的全部,只消三言两语便可阐明。 译文卫:相反,对于这个机敏的年轻人来说,法律这门高贵科学的全部,就存在于一只干果壳中,只消三言两语便可阐明。 显然译文B似更可取。但是,翻译本文标题,这个nutshell的形象,就无法挽留了。也许只能译成:简言之,性促销。展开更多
The use of natural fibers as an additive in polymeric matrices has attracted interest of the automotive industries,for its low cost,mechanical properties,biodegradability and lightness.However,the hydrophilic nature o...The use of natural fibers as an additive in polymeric matrices has attracted interest of the automotive industries,for its low cost,mechanical properties,biodegradability and lightness.However,the hydrophilic nature of the fiber makes polymer compatibility difficult.Fiber surface treatments can be used to enhance the fiber/matrix interface.In the present work,polypropylene(PP)composites reinforced with fibers from macadamia nutshell were obtained and characterized.Macadamia nutshell fibers were treated by an alkaline treatment with sodium hydroxide(NaOH 4%)to improve adhesion between fibers and matrix.Fibers were characterized by techniques of Scanning Electron Microscopy(SEM)and X-Ray Diffraction(XRD).The PP was mixed with the macadamia fibers(treated and untreated),in proportions of 5 and 10%(wt/wt)using a thermokinetic mixer.Furthermore tensile,flexural and impact specimens(Pure PP and composites)were prepared by an injection molding process and tested for evaluation of mechanical properties.The results showed that the insertion of treated fibers in the PP matrix increased the stiffness of the composites.However,the composites reinforced with untreated fibers presented higher impact energy absorption when compared to composites reinforced with treated fibers.展开更多
【目的】分析果壳的热解特性及与果壳中纤维素、木质素及半纤维素的相关性,为果壳类生物质的热化学转化利用提供基础数据。【方法】分析油茶壳、椰子壳、油桐壳、核桃壳、板栗壳、开心果壳和腰果壳的纤维素、木质素和半纤维素含量,并进...【目的】分析果壳的热解特性及与果壳中纤维素、木质素及半纤维素的相关性,为果壳类生物质的热化学转化利用提供基础数据。【方法】分析油茶壳、椰子壳、油桐壳、核桃壳、板栗壳、开心果壳和腰果壳的纤维素、木质素和半纤维素含量,并进行热重分析,同时分析7种果壳的热解失重峰值温度与果壳中纤维素、木质素和半纤维素含量的相关性。【结果】除腰果壳外,其他6种果壳的主要成分为纤维素、酸不溶木质素和半纤维素,三者总含量均在73%以上,腰果壳中纤维素、半纤维素和酸不溶木质素三者总含量仅为47.41%。除油桐壳以外,其他6种果壳在200~410℃温度范围均出现多个热解失重峰,椰子壳、油茶壳、开心果壳与腰果壳最高温热解失重峰的左侧出现明显的尖状热解失重峰,核桃壳和板栗壳则在最高温热解失重峰的左侧出现肩状热解失重峰。7种果壳的热解动力学模型符合一级动力学方程,热解活化能在40~85 k J·mol^(-1)之间。果壳的最高温热解峰峰值温度与果壳中木质素含量呈明显的正相关性(R=0.800,P=0.03<0.05),与纤维素含量的正相关性较弱(R=0.446,P=0.32>0.05),与半纤维素含量呈较弱的正相关性(R=0.509,P=0.24>0.05),与果壳中木质素和纤维素总含量的正相关性更显著(R=0.899,P=0.005<0.05)。7种果壳(除油桐壳外)左侧热解峰的峰值温度与半纤维素含量呈明显的正相关性(R=0.836,P=0.04<0.05),与木质素含量呈弱的正相关性(R=0.484,P=0.33>0.05),而与纤维素含量的正相关性更弱(R=0.295,P=0.57>0.05)。【结论】7种果壳中纤维素、木质素与半纤维素含量不同,各具有不同的热解特性,其最高温热解峰峰值温度主要受果壳中木质素含量的影响,而其左侧热解峰峰值温度主要受果壳中半纤维素含量的影响。展开更多
文摘Now one of the main cash crops in Côte d’Ivoire, the cashew tree feeds an entire industrial sector based on the processing of its fruit. This processing generates a large volume of waste, consisting of cashew nutshells, the management of which poses environmental problems. With the aim of replacing charcoal and firewood with more environmentally friendly fuels, several studies are currently being carried out into the optimal use of cashew shells in fuel briquettes. To assess the environmental sustainability of these briquettes, this study calculates the environmental impacts associated with their life cycle, compares them with those of charcoal and firewood, and identifies the processes that contribute most to environmental pollution, with a view to improving them. Analysis of the results showed that cashew nutshell briquettes emit a range of pollutants over their life cycle that damage the environment and are responsible for the 7 impact categories considered: acidification, eutrophication, freshwater aquatic ecotoxicity, global warming, human toxicity, photochemical oxidation and terrestrial ecotoxicity potential. However, they are more environmentally friendly than charcoal and firewood for 5 impact categories: freshwater aquatic ecotoxicity, global warming, human toxicity, photochemical oxidation and terrestrial ecotoxicity potential. The 3 elementary processes, i.e. transport of biomass raw materials, production, and combustion of briquettes, emit pollutants that contribute most to the creation of environmental impact categories. The most relevant pollutants are nitrogen oxides (NOx), sulphur oxides (SOx) and particulate matter (PM).
基金the National Natural Science Foundation of China(Grant No.51475002)。
文摘The parameters of energy and power for nut rupturing play a key role in the design of shell-breaking equipment.However,currently,there is no scientifically accurate measuring method for these parameters.A mechanical nut testbed was developed to accurately measure the force,energy,and power and observe the generating process of nutshell cracking and breaking to reveal the shell-breaking mechanism.The system was tested with pecans and the results show that the testbed can effectively realize the determination of nuts performance and data acquisition and analysis.The methods and data can provide a theoretical guidance for the design and optimization of shell-breaking equipment and decrease kernel-breaking rate.
文摘北京理工大学的刁文景老师为本栏目发来一稿。其译文相当不错,我们编者为其译文,添加了“评注”,点评翻译的难点以及原文的妙处。希望读者喜欢,而不至于认为“评注”是“蛇足”。文章的标题也存在一个英语成语:in anutshell。nutshell者,坚果壳也。一个坚果壳中能容纳多少东西呢?因此,in anutshell的含义猜想可知:简单地,简约地。人们在翻译这个英语成语时,常殚精竭虑,试图译出成语中的nutshell,如: Instead,to this quick-witted youth,the whole noble science of the law was Contained in a nutshell. 译文A:相反,对于这个机敏的年轻人来说,法律这门高贵科学的全部,只消三言两语便可阐明。 译文卫:相反,对于这个机敏的年轻人来说,法律这门高贵科学的全部,就存在于一只干果壳中,只消三言两语便可阐明。 显然译文B似更可取。但是,翻译本文标题,这个nutshell的形象,就无法挽留了。也许只能译成:简言之,性促销。
文摘The use of natural fibers as an additive in polymeric matrices has attracted interest of the automotive industries,for its low cost,mechanical properties,biodegradability and lightness.However,the hydrophilic nature of the fiber makes polymer compatibility difficult.Fiber surface treatments can be used to enhance the fiber/matrix interface.In the present work,polypropylene(PP)composites reinforced with fibers from macadamia nutshell were obtained and characterized.Macadamia nutshell fibers were treated by an alkaline treatment with sodium hydroxide(NaOH 4%)to improve adhesion between fibers and matrix.Fibers were characterized by techniques of Scanning Electron Microscopy(SEM)and X-Ray Diffraction(XRD).The PP was mixed with the macadamia fibers(treated and untreated),in proportions of 5 and 10%(wt/wt)using a thermokinetic mixer.Furthermore tensile,flexural and impact specimens(Pure PP and composites)were prepared by an injection molding process and tested for evaluation of mechanical properties.The results showed that the insertion of treated fibers in the PP matrix increased the stiffness of the composites.However,the composites reinforced with untreated fibers presented higher impact energy absorption when compared to composites reinforced with treated fibers.
文摘【目的】分析果壳的热解特性及与果壳中纤维素、木质素及半纤维素的相关性,为果壳类生物质的热化学转化利用提供基础数据。【方法】分析油茶壳、椰子壳、油桐壳、核桃壳、板栗壳、开心果壳和腰果壳的纤维素、木质素和半纤维素含量,并进行热重分析,同时分析7种果壳的热解失重峰值温度与果壳中纤维素、木质素和半纤维素含量的相关性。【结果】除腰果壳外,其他6种果壳的主要成分为纤维素、酸不溶木质素和半纤维素,三者总含量均在73%以上,腰果壳中纤维素、半纤维素和酸不溶木质素三者总含量仅为47.41%。除油桐壳以外,其他6种果壳在200~410℃温度范围均出现多个热解失重峰,椰子壳、油茶壳、开心果壳与腰果壳最高温热解失重峰的左侧出现明显的尖状热解失重峰,核桃壳和板栗壳则在最高温热解失重峰的左侧出现肩状热解失重峰。7种果壳的热解动力学模型符合一级动力学方程,热解活化能在40~85 k J·mol^(-1)之间。果壳的最高温热解峰峰值温度与果壳中木质素含量呈明显的正相关性(R=0.800,P=0.03<0.05),与纤维素含量的正相关性较弱(R=0.446,P=0.32>0.05),与半纤维素含量呈较弱的正相关性(R=0.509,P=0.24>0.05),与果壳中木质素和纤维素总含量的正相关性更显著(R=0.899,P=0.005<0.05)。7种果壳(除油桐壳外)左侧热解峰的峰值温度与半纤维素含量呈明显的正相关性(R=0.836,P=0.04<0.05),与木质素含量呈弱的正相关性(R=0.484,P=0.33>0.05),而与纤维素含量的正相关性更弱(R=0.295,P=0.57>0.05)。【结论】7种果壳中纤维素、木质素与半纤维素含量不同,各具有不同的热解特性,其最高温热解峰峰值温度主要受果壳中木质素含量的影响,而其左侧热解峰峰值温度主要受果壳中半纤维素含量的影响。
