Eucalyptus sawdust is a residue from fast-growing forest processing.Utilization of Eucalyptus sawdust as fuel by co-pelletization with natural forest sawdust could solve problems of waste disposal and material supply ...Eucalyptus sawdust is a residue from fast-growing forest processing.Utilization of Eucalyptus sawdust as fuel by co-pelletization with natural forest sawdust could solve problems of waste disposal and material supply limitation of pellet production.This work targeted at providing a useful reference for improving pellet properties and optimizing variable combinations.Experiments were arranged using response surface methodology with a central composite design and carried out using a uniaxial piston-cylinder densification apparatus.Based on the analysis of variance of effects of variables on responses,the optimal models were all selected as quadratic and expressed in the form of regression equations.The differences between adjusted R2 and predicted R2 are all within 0.2 and the adequate precision is all greater than four illustrating the reliability of the established models.The optimal variable combinations were obtained according to the desired response goals and validation experiments were conducted.Errors between response predicted and actual values were calculated and applied to improve the model accuracy.After modification,final errors were reduced to less than 9%and could be accepted by pellet production.Experimental results also demonstrated that pellet properties and higher heating value were all increased by co-pelletization and optimization.This will be very beneficial for pellet application.Furthermore,these results could provide the required data for designing a suitable machine of pellet production.展开更多
Sewage sludge（SS） and deinking sludge（DS） were used to comparatively study the hydrothermal dewatering of sludge with different components. For a better overview, an insight into the relationship between physicoch...Sewage sludge（SS） and deinking sludge（DS） were used to comparatively study the hydrothermal dewatering of sludge with different components. For a better overview, an insight into the relationship between physicochemical properties and dewaterability of hydrothermal sludge was provided. Results found that not all kinds of sludge were suitably conditioned by hydrothermal treatment（HT） in term of the elevation of dewaterability.Higher hydrothermal temperature tended to enhance the dewaterability of SS rather than DS, which was supported by the variation of their physicochemical properties（including water distribution, bonding energy, extracellular polymeric substance（EPS）, particles size,acid functional groups and zeta potential in this study）. In addition, the changes in surface morphology suggested that the reverse effect of HT on sludge dewaterability was mainly due to their dewatering behavior. For SS, the destruction of EPS structure leaded to the release of bound water, thereby strengthening sludge dewatering. Conversely, ＂Bridging effect＂ generated by lignocellulose in DS was beneficial for sludge dewatering; however, the increasing hydrothermal temperature degraded part of lignocellulose and weakened＂bridging effect＂, finally resulting in worse dewaterability of DS.展开更多
An improved tum-on aptasensor for thrombin detection using split aptamer fragments and graphene oxide （GO） was reported. The thrombin-binding aptamer （Aptl5） was split into two parts for target recognition, an 8-b...An improved tum-on aptasensor for thrombin detection using split aptamer fragments and graphene oxide （GO） was reported. The thrombin-binding aptamer （Aptl5） was split into two parts for target recognition, an 8-base se- quence labeled with fluorescein （FAM-Apt-A） and a 7-base oligonucleotide sequence （Apt-B）. In the absence of target protein, the fluorescence of FAM-Apt-A/Apt-B was quenched by GO through n-n stacking between GO and single-stranded DNA. However, when thrombin was introduced into the system, a target-induced G-quadruplex forms with two split aptamer fragments and thrombin. The fluorescence recovered due to weak interaction between G-quadruplex and GO. Compared to the strategy using intact aptamer, probe concentration was lowered, and an improved sensitivity was obtained. Moreover, heating process to avoid unfavorable secondary structure was avoided due to the use of shorter split aptamer fragments.展开更多
基金This work was supported by the National KeyResearch and Development Program of China(2018YFC1901204)Science and TechnologyProgram of Guangzhou (grant number201803030006)+2 种基金Dalian National Laboratory for CleanEnergy (DNL) Cooperation Fund, the CAS (grantnumber DNL180306)Guangdong InternationalScience and Technology Innovation Fund (grantnumber 2019A050510031)S&T Project of State GridCorporation of China (grant number JNX-2018-052).
文摘Eucalyptus sawdust is a residue from fast-growing forest processing.Utilization of Eucalyptus sawdust as fuel by co-pelletization with natural forest sawdust could solve problems of waste disposal and material supply limitation of pellet production.This work targeted at providing a useful reference for improving pellet properties and optimizing variable combinations.Experiments were arranged using response surface methodology with a central composite design and carried out using a uniaxial piston-cylinder densification apparatus.Based on the analysis of variance of effects of variables on responses,the optimal models were all selected as quadratic and expressed in the form of regression equations.The differences between adjusted R2 and predicted R2 are all within 0.2 and the adequate precision is all greater than four illustrating the reliability of the established models.The optimal variable combinations were obtained according to the desired response goals and validation experiments were conducted.Errors between response predicted and actual values were calculated and applied to improve the model accuracy.After modification,final errors were reduced to less than 9%and could be accepted by pellet production.Experimental results also demonstrated that pellet properties and higher heating value were all increased by co-pelletization and optimization.This will be very beneficial for pellet application.Furthermore,these results could provide the required data for designing a suitable machine of pellet production.
基金supported by the National Natural Science Foundation of China(Nos.51676195)the National Natural Science Foundation of China(Nos.51661145022)the Special Program for Key Basic Research of the Natural Science Foundation of Guangdong Province(No.2017B030308002)
文摘Sewage sludge（SS） and deinking sludge（DS） were used to comparatively study the hydrothermal dewatering of sludge with different components. For a better overview, an insight into the relationship between physicochemical properties and dewaterability of hydrothermal sludge was provided. Results found that not all kinds of sludge were suitably conditioned by hydrothermal treatment（HT） in term of the elevation of dewaterability.Higher hydrothermal temperature tended to enhance the dewaterability of SS rather than DS, which was supported by the variation of their physicochemical properties（including water distribution, bonding energy, extracellular polymeric substance（EPS）, particles size,acid functional groups and zeta potential in this study）. In addition, the changes in surface morphology suggested that the reverse effect of HT on sludge dewaterability was mainly due to their dewatering behavior. For SS, the destruction of EPS structure leaded to the release of bound water, thereby strengthening sludge dewatering. Conversely, ＂Bridging effect＂ generated by lignocellulose in DS was beneficial for sludge dewatering; however, the increasing hydrothermal temperature degraded part of lignocellulose and weakened＂bridging effect＂, finally resulting in worse dewaterability of DS.
文摘An improved tum-on aptasensor for thrombin detection using split aptamer fragments and graphene oxide （GO） was reported. The thrombin-binding aptamer （Aptl5） was split into two parts for target recognition, an 8-base se- quence labeled with fluorescein （FAM-Apt-A） and a 7-base oligonucleotide sequence （Apt-B）. In the absence of target protein, the fluorescence of FAM-Apt-A/Apt-B was quenched by GO through n-n stacking between GO and single-stranded DNA. However, when thrombin was introduced into the system, a target-induced G-quadruplex forms with two split aptamer fragments and thrombin. The fluorescence recovered due to weak interaction between G-quadruplex and GO. Compared to the strategy using intact aptamer, probe concentration was lowered, and an improved sensitivity was obtained. Moreover, heating process to avoid unfavorable secondary structure was avoided due to the use of shorter split aptamer fragments.
