The spread of pine nematode disease caused by epidemic wood poses a great challenge to the environment,and there is an urgent need to develop effective processing methods;however,Ca/Fe-rich sludge ash can improve the ...The spread of pine nematode disease caused by epidemic wood poses a great challenge to the environment,and there is an urgent need to develop effective processing methods;however,Ca/Fe-rich sludge ash can improve the pyrolysis properties of biomass.Therefore,this paper focuses on the pyrolysis mechanism of epidemic wood with the addition of Ca/Fe-rich sludge ash.The presence of Ca-rich sludge ash was found to extend the pyrolytic temperature window of epidemic wood,intensify the cracking of its volatile constituents,and extend its reaction duration.At the same time,the Ca-rich sludge reduces the pyrolysis activation energy to 152.39 kJ/mol.The Fe-rich sludge ash demonstrated the capacity to lower the energy barriers during the initial phase of pyrolysis.Concurrently,the Ca-rich sludge ash accelerated the dehydration reaction of the epidemic wood,leading to 21.02%and 30.69%increases in the contents of acids and ketones in the pyrolytic oil,respectively.The Fe-rich sludge ash contributed to a notable 14.52%increase in aromatic compounds in the oil and a 19.14%decrease in alcoholic compounds.Additionally,the Ca-rich sludge ash accelerated the decomposition of lipid organic matter at elevated temperatures,enriching the pyrolytic char with more unsaturated bonds.This research lays a theoretical foundation for the safe and efficacious thermal decomposition of epidemic wood,thereby enhancing its utilization within the forestry industry.展开更多
Trace amounts of Zr and V can increase the recrystallization temperature of Al-Mg-Si wrought aluminum alloys,which is expected to regulate the recrystallization grain.In this paper,trace amounts of V and Zr were added...Trace amounts of Zr and V can increase the recrystallization temperature of Al-Mg-Si wrought aluminum alloys,which is expected to regulate the recrystallization grain.In this paper,trace amounts of V and Zr were added to recycled Al-Mg-Si alloys,and their e ffects on the microstructure and mechanical properties of the cast alloys were studied by scanning electron microscopy(SEM)and synchrotron radiation X-ray tomography(SRXT).The results show that the addition of Zr significantly increases the grain sizes due to the“Zr poisoning”;V addition has no significant effect on the grain size.The morphology of Fe-rich phase gradually changes from the large Chinese-script shape to the fine short rod and curved long strip shape,and the distribution uniformity is improved with the combined addition of V and Zr.The three-dimensional(3 D)morphology of Fe-rich phase includes granular,short rod-like,simple branch and multi-branch structures.The individual addition of V and Zr has no significant effect on the morphology of Fe-rich phase;but the combined addition of V and Zr significantly increases the number and volume fraction of Fe-rich phase with small size(diameter£15μm),the number of branches in the largest Fe-rich phase is significantly reduced,resulting in the improvement of elongation.This work provides a theoretical basis for the development of new recycled Al-Mg-Si alloys in industrial application.展开更多
Carbon fiber-reinforced carbon aerogel(C/CA)composites are one of the most promising candidates for applications requiring both thermal insulation and load bearing capabilities.The preparation of anti-oxidation coatin...Carbon fiber-reinforced carbon aerogel(C/CA)composites are one of the most promising candidates for applications requiring both thermal insulation and load bearing capabilities.The preparation of anti-oxidation coatings on C/CA to address its susceptibility to oxidation is a feasible approach to promote its application in oxidative environments.However,the currently reported coatings on C/CA mainly focus on improving the ablation performance and coating preparation process typically necessitating high-temperature heat treatment.This procedure can increase its thermal conductivity and reduce its thermal insulation ability.In this study,a series of ceramic-resin coatings were fabricated on C/CA through a simple slurry brushing-drying approach at room temperature.The effects of phenolic resin content on the coating structure,residual stress,thermal shock,and oxidation behaviors were investigated.Due to the adhesive properties and curing-induced shrinkage,the PR-7.5 coating(containing 7.5%(in mass)phenolic resin in the slurry)exhibits bonding strength close to fracture strength of the substrate and residual compressive stress of 0.853 GPa,which is beneficial for resisting thermal shock cracking.However,excessive resin content(PR-10.0 containing 10.0%(in mass)phenolic resin in the slurry)induces tensile stress due to uneven curing shrinkage,thereby leading to thermal shock cracking.Meanwhile,oxidation tests reveal significantly reduced weight losses for PR-7.5(17.46%at 800℃/100 min,8.15%at 1000℃/120 min,3.15%at 1200℃/120 min)versus uncoated C/CA’s 44.60%loss at 800℃/20 min.This work provides a brand-new and simple approach to improving the anti-oxidation performance of C/CA and expands its application in mild oxidative environments.展开更多
基金supported by the Projects of Intergovernmental Cooperation of Science and Technology/National Key Research and Development Program of China(No.2024YFE0100200)the National Natural Science Foundation of China(No.52236008)+1 种基金the Zhejiang Provincial Natural Science Foundation(No.LZ23E060004)the National Natural Science Foundation of China(No.52206178).
文摘The spread of pine nematode disease caused by epidemic wood poses a great challenge to the environment,and there is an urgent need to develop effective processing methods;however,Ca/Fe-rich sludge ash can improve the pyrolysis properties of biomass.Therefore,this paper focuses on the pyrolysis mechanism of epidemic wood with the addition of Ca/Fe-rich sludge ash.The presence of Ca-rich sludge ash was found to extend the pyrolytic temperature window of epidemic wood,intensify the cracking of its volatile constituents,and extend its reaction duration.At the same time,the Ca-rich sludge reduces the pyrolysis activation energy to 152.39 kJ/mol.The Fe-rich sludge ash demonstrated the capacity to lower the energy barriers during the initial phase of pyrolysis.Concurrently,the Ca-rich sludge ash accelerated the dehydration reaction of the epidemic wood,leading to 21.02%and 30.69%increases in the contents of acids and ketones in the pyrolytic oil,respectively.The Fe-rich sludge ash contributed to a notable 14.52%increase in aromatic compounds in the oil and a 19.14%decrease in alcoholic compounds.Additionally,the Ca-rich sludge ash accelerated the decomposition of lipid organic matter at elevated temperatures,enriching the pyrolytic char with more unsaturated bonds.This research lays a theoretical foundation for the safe and efficacious thermal decomposition of epidemic wood,thereby enhancing its utilization within the forestry industry.
基金Project(2024YEE0109100) supported by the National Key R&D Program of ChinaProjects(52074131,52104373) supported by the National Natural Science Foundation of ChinaProjects(2022YFJH001,2024YFJH001) supported by the Science and Technology Plan Program of Qingyuan City,China。
文摘Trace amounts of Zr and V can increase the recrystallization temperature of Al-Mg-Si wrought aluminum alloys,which is expected to regulate the recrystallization grain.In this paper,trace amounts of V and Zr were added to recycled Al-Mg-Si alloys,and their e ffects on the microstructure and mechanical properties of the cast alloys were studied by scanning electron microscopy(SEM)and synchrotron radiation X-ray tomography(SRXT).The results show that the addition of Zr significantly increases the grain sizes due to the“Zr poisoning”;V addition has no significant effect on the grain size.The morphology of Fe-rich phase gradually changes from the large Chinese-script shape to the fine short rod and curved long strip shape,and the distribution uniformity is improved with the combined addition of V and Zr.The three-dimensional(3 D)morphology of Fe-rich phase includes granular,short rod-like,simple branch and multi-branch structures.The individual addition of V and Zr has no significant effect on the morphology of Fe-rich phase;but the combined addition of V and Zr significantly increases the number and volume fraction of Fe-rich phase with small size(diameter£15μm),the number of branches in the largest Fe-rich phase is significantly reduced,resulting in the improvement of elongation.This work provides a theoretical basis for the development of new recycled Al-Mg-Si alloys in industrial application.
基金National Natural Science Foundation of China(52272075,52472053)Research Fund of Youth Innovation Promotion Association of CAS,China(2021190)Defense Industrial Technology Development Program(JCKY2021130B007)。
文摘Carbon fiber-reinforced carbon aerogel(C/CA)composites are one of the most promising candidates for applications requiring both thermal insulation and load bearing capabilities.The preparation of anti-oxidation coatings on C/CA to address its susceptibility to oxidation is a feasible approach to promote its application in oxidative environments.However,the currently reported coatings on C/CA mainly focus on improving the ablation performance and coating preparation process typically necessitating high-temperature heat treatment.This procedure can increase its thermal conductivity and reduce its thermal insulation ability.In this study,a series of ceramic-resin coatings were fabricated on C/CA through a simple slurry brushing-drying approach at room temperature.The effects of phenolic resin content on the coating structure,residual stress,thermal shock,and oxidation behaviors were investigated.Due to the adhesive properties and curing-induced shrinkage,the PR-7.5 coating(containing 7.5%(in mass)phenolic resin in the slurry)exhibits bonding strength close to fracture strength of the substrate and residual compressive stress of 0.853 GPa,which is beneficial for resisting thermal shock cracking.However,excessive resin content(PR-10.0 containing 10.0%(in mass)phenolic resin in the slurry)induces tensile stress due to uneven curing shrinkage,thereby leading to thermal shock cracking.Meanwhile,oxidation tests reveal significantly reduced weight losses for PR-7.5(17.46%at 800℃/100 min,8.15%at 1000℃/120 min,3.15%at 1200℃/120 min)versus uncoated C/CA’s 44.60%loss at 800℃/20 min.This work provides a brand-new and simple approach to improving the anti-oxidation performance of C/CA and expands its application in mild oxidative environments.
