This study considers the effect of Eichhornia Crassipes Biodiesel(ECB)blends on the performances,combustion,and emission characteristics of a direct injection compression ignition engine operated in a dual-fuel mode(D...This study considers the effect of Eichhornia Crassipes Biodiesel(ECB)blends on the performances,combustion,and emission characteristics of a direct injection compression ignition engine operated in a dual-fuel mode(DFM)and equipped with an Exhaust gas recirculation technique(EGR).In particular,a single-cylinder,four-stroke,water-cooled diesel engine was utilized and four modes of fuel operation were considered:mode I,the engine operated with an ordinary diesel fuel;mode II,the engine operated with the addition of 2.4 L/min of lique-fied petroleum gas(LPG)and 20%EGR;mode III,20%ECB with 2.4 L/min LPG and 20%EGR;mode IV,40%ECB with 2.4 L/min LPG and 20%EGR.The operation conditions were constant engine speed(1500 rpm),var-iation of load(25%,50%,75%,and 100%),full load,with a compression ratio of 18,and a time injection of 23°BTDC(Before top died center).With regard to engine emissions,carbon dioxide(CO_(2)),carbon monoxide(CO),hydrocarbons(UHC),and nitrogen oxide(NOX)were measured using a gas analyzer.The smoke opacity was measured using an OPABOX smoke meter.By comparing the results related to the different modes with mode I at full load,the BTE(Brake thermal efficiency)increased by 20.17%,11.45%,and 12.66%with modes II,III,and IV,respectively.In comparison to the results for mode II,the BTE decreased due to the combustion of ECB blends by 7.26%and 6.24%for mode III and mode IV,respectively,at full load.In comparison to mode II,the Brake specific energy consumption(BSEC)increased with the ECB substitution.With ECB blends,there is a noticeable decrease in the CO,CO_(2),and UHC emissions at a partial load.Furthermore,the 20%ECB has no effect on CO emissions at full load.For modes II and IV,the CO_(2)increased by 33.33%and 19%,respectively,while the UHC emissions were reduced by 14.49%for mode III and 26.08%for mode IV.The smoke of mode III was lower by 7.21%,but for mode IV,it was higher by 12.37%.In addition,with mode III and mode IV,the NOx emissions increased by 30.50%and 18.80%,respectively.展开更多
The hydrothermal/soft templating method is an effective way to synthesize ordered mesoporous carbon(OMC),yet the mechanism of this strategy is not well illustrated.Herein,a hydrothermal temperature-controlled approach...The hydrothermal/soft templating method is an effective way to synthesize ordered mesoporous carbon(OMC),yet the mechanism of this strategy is not well illustrated.Herein,a hydrothermal temperature-controlled approach is developed to precisely synthesize OMCs with well-defined morphologies from liquefied wood(LW).As the hydrothermal temperature increases from 130 to 210◦C,the hydrophilicity of the hydrophilic blocks decreases accompanied by the increase of the rel-ative volume of the hydrophobic block,resulting in the packing parameter p of micelles changing from p≤1/3 to 1/3<p<1/2,which transforms the micelle’s structure from spherical to cylindrical.Additionally,accelerated nucle-ation occurred with the increased hydrothermal temperature.When the rate of nucleation is matched to the self-assembly of the composite micelles,the compos-ite micelles grow into worm-like morphology and an ordered p6m mesostructure.This hydrothermal temperature-controlled strategy provides a straightforward and effective approach for synthesizing OMCs with various morphologies from LW,addressing the previously insufficiently elucidated micelle formation mechanism in the hydrothermal/soft templating method.展开更多
Effective stress analysis is performed to evaluate the residual displacement of a caisson quaywall during 1994 Hokkaido- Toho- Oki Earthquake and 1993 Kushiro- Oki Earthquake. The constitutive model used in this study...Effective stress analysis is performed to evaluate the residual displacement of a caisson quaywall during 1994 Hokkaido- Toho- Oki Earthquake and 1993 Kushiro- Oki Earthquake. The constitutive model used in this study is a multiple shear mechanism type defined in strain space and can take into account the effect of rotation of principal stress axis. The earthquake accelerations recorded at the outcropping rock during the earthquake are used as input bedrock motion. The results of finite element analysis are in good agreement with the observed behaviour of the quaywall. The analysis also indicates that liquefaction and high excess porewater pressure have a significant effect on the deformation of the caisson. Soil improvement is speculated as the most reliable measures against liquefaction. The influence of soil improvement and the reasonable improved area are discussed in the paper.展开更多
文摘This study considers the effect of Eichhornia Crassipes Biodiesel(ECB)blends on the performances,combustion,and emission characteristics of a direct injection compression ignition engine operated in a dual-fuel mode(DFM)and equipped with an Exhaust gas recirculation technique(EGR).In particular,a single-cylinder,four-stroke,water-cooled diesel engine was utilized and four modes of fuel operation were considered:mode I,the engine operated with an ordinary diesel fuel;mode II,the engine operated with the addition of 2.4 L/min of lique-fied petroleum gas(LPG)and 20%EGR;mode III,20%ECB with 2.4 L/min LPG and 20%EGR;mode IV,40%ECB with 2.4 L/min LPG and 20%EGR.The operation conditions were constant engine speed(1500 rpm),var-iation of load(25%,50%,75%,and 100%),full load,with a compression ratio of 18,and a time injection of 23°BTDC(Before top died center).With regard to engine emissions,carbon dioxide(CO_(2)),carbon monoxide(CO),hydrocarbons(UHC),and nitrogen oxide(NOX)were measured using a gas analyzer.The smoke opacity was measured using an OPABOX smoke meter.By comparing the results related to the different modes with mode I at full load,the BTE(Brake thermal efficiency)increased by 20.17%,11.45%,and 12.66%with modes II,III,and IV,respectively.In comparison to the results for mode II,the BTE decreased due to the combustion of ECB blends by 7.26%and 6.24%for mode III and mode IV,respectively,at full load.In comparison to mode II,the Brake specific energy consumption(BSEC)increased with the ECB substitution.With ECB blends,there is a noticeable decrease in the CO,CO_(2),and UHC emissions at a partial load.Furthermore,the 20%ECB has no effect on CO emissions at full load.For modes II and IV,the CO_(2)increased by 33.33%and 19%,respectively,while the UHC emissions were reduced by 14.49%for mode III and 26.08%for mode IV.The smoke of mode III was lower by 7.21%,but for mode IV,it was higher by 12.37%.In addition,with mode III and mode IV,the NOx emissions increased by 30.50%and 18.80%,respectively.
基金National Natural Science Foundation of China,Grant/Award Number:32371808Fundamental Research Funds for the Central Universities,Grant/Award Number:2572023CT06。
文摘The hydrothermal/soft templating method is an effective way to synthesize ordered mesoporous carbon(OMC),yet the mechanism of this strategy is not well illustrated.Herein,a hydrothermal temperature-controlled approach is developed to precisely synthesize OMCs with well-defined morphologies from liquefied wood(LW).As the hydrothermal temperature increases from 130 to 210◦C,the hydrophilicity of the hydrophilic blocks decreases accompanied by the increase of the rel-ative volume of the hydrophobic block,resulting in the packing parameter p of micelles changing from p≤1/3 to 1/3<p<1/2,which transforms the micelle’s structure from spherical to cylindrical.Additionally,accelerated nucle-ation occurred with the increased hydrothermal temperature.When the rate of nucleation is matched to the self-assembly of the composite micelles,the compos-ite micelles grow into worm-like morphology and an ordered p6m mesostructure.This hydrothermal temperature-controlled strategy provides a straightforward and effective approach for synthesizing OMCs with various morphologies from LW,addressing the previously insufficiently elucidated micelle formation mechanism in the hydrothermal/soft templating method.
文摘Effective stress analysis is performed to evaluate the residual displacement of a caisson quaywall during 1994 Hokkaido- Toho- Oki Earthquake and 1993 Kushiro- Oki Earthquake. The constitutive model used in this study is a multiple shear mechanism type defined in strain space and can take into account the effect of rotation of principal stress axis. The earthquake accelerations recorded at the outcropping rock during the earthquake are used as input bedrock motion. The results of finite element analysis are in good agreement with the observed behaviour of the quaywall. The analysis also indicates that liquefaction and high excess porewater pressure have a significant effect on the deformation of the caisson. Soil improvement is speculated as the most reliable measures against liquefaction. The influence of soil improvement and the reasonable improved area are discussed in the paper.
