In this study,wheat straw pulp was prepared by sulfiteformaldehyde(SF) pulping combined with oxygen delignification to develop a sustainable methodology for chemical pulping of straw materials.The bleachability of oxy...In this study,wheat straw pulp was prepared by sulfiteformaldehyde(SF) pulping combined with oxygen delignification to develop a sustainable methodology for chemical pulping of straw materials.The bleachability of oxygen-delignified SF pulp was also evaluated by hypochlorite bleaching.The results indicated that the Na_2SO_3 charge played an important role in lignin removal during SF pulping as well as oxygen delignification.The efficiency of oxygen delignification of wheat straw SF pulp was markedly high.After the oxygenation stage,the Kappa number decreased by over 50%(the original Kappa number of SF pulp was lower than 30) when the Na OH charge was in the range of 3%~5%.The optimal conditions for preparing bleached pulp via combined SF pulping and oxygen delignification involved the use of 12% of Na_2SO_3 and 3% of Na OH,respectively.Pulp with relatively high brightness,a low Kappa number,as well as an acceptable viscosity could be obtained when oxygen-delignified SF pulp was bleached with hypochlorite under a low active chlorine dosage.展开更多
Based on the on-site investigation and the principle of compressible flow, the working oxygen pressure should be matched to the Mach-number at the nozzle in designing nozzle and oxygen supply schedule so that the high...Based on the on-site investigation and the principle of compressible flow, the working oxygen pressure should be matched to the Mach-number at the nozzle in designing nozzle and oxygen supply schedule so that the higher penetration depth and the more blending energy can be obtained for reducing energy loss by shock wave in the ultrasonic oxygen jet in the normal BOF steelmaking. For some special BOF blowing technologies, such as steelmaking with high phosphorus hot metal, post combustion oxygen lance, hot metal pretreatment, etc, the difference between working oxygen pressure and designed diffusion pressure which is related to Mach-number is necessary, so that the velocity of the oxygen jet will be decreased because of shock wave for expected metallurgical results.展开更多
The analyses of water from four tributaries of Ikpa River: Afaha Nsai Stream (ANS), Ikot Ekpuk Stream (IES), Afaha Itam Stream(AIS) and Nduetong Stream (NDS) in International Telecommunication Union (ITU) Local Gover...The analyses of water from four tributaries of Ikpa River: Afaha Nsai Stream (ANS), Ikot Ekpuk Stream (IES), Afaha Itam Stream(AIS) and Nduetong Stream (NDS) in International Telecommunication Union (ITU) Local Government Area of Akawa Ibom State in Nigeria were carried out using standard analytical procedures. The parameters investigated were temperature(Temp.), hydrogen ion concentration(pH), total suspended solids (TSS), total dissolved solids (TDS), dissolved oxygen (DO) and biochemical oxygen demand (BOD). Correlation analysis carried out between pairs of variables showed that only the correlation coefficients between TDS and DO in ANS( p <0.05); Temp. and TDS in IES ( p <0.05) and between Temp. and TDS in AIS ( p <0.01) were significant. None of the pairs of the variables in NDS showed any significant correlation. The coefficients of variation for the parameters were also computed and used in determining their stability in the water. The possible effects of these variables on each other and on the aquatic ecosystem were discussed.展开更多
The purpose of this paper is to study the effect of oxygenate additives into gasoline for the improvement of physicochemical properties of blends.Methyl Tertiary Butyl Ether（MTBE）,Methanol,Tertiary butyl alcohol（TB...The purpose of this paper is to study the effect of oxygenate additives into gasoline for the improvement of physicochemical properties of blends.Methyl Tertiary Butyl Ether（MTBE）,Methanol,Tertiary butyl alcohol（TBA）,and Tertiary amyl alcohol（TAA） blend into unleaded gasoline with various blended rates of 2.5%,5%,7.5%,10%,15%,and 20%.Physicochemical properties of blends are analyzed by the standard American Society of Testing and Materials（ASTM） methods.Methanol,TBA,and TAA increase density of the mixtures,but MTBE decreases density.The addition of oxygenates lead to a distortion of the base gasoline＇s distillation curves.The Reid vapor pressure（RVP） of gasoline is found to increase with the addition of the oxygenated compounds.All oxygenates improve both motor and research octane numbers.Among these four additives,TBA shows the best fuel properties.展开更多
A new method for estimating the degree of [SiO4]4-polymerization of coal gangue is presented. The method uses the relative bridging oxygen number (RBO) based on nuclear magnetic resonance (NMR) techniques. X-ray diffr...A new method for estimating the degree of [SiO4]4-polymerization of coal gangue is presented. The method uses the relative bridging oxygen number (RBO) based on nuclear magnetic resonance (NMR) techniques. X-ray diffraction (XRD) and 29Si NMR techniques have been used to study phase transitions and silicate polymerization of coal gangue calcined at different temperatures or co-calcined. It has been found that phase transition of clay minerals causes silicate polymerization to change with temperature. In this study, cementing activity and RBO were determined to be inversely related. Generally, activated coal gangue with lower RBO had better cementitious activity.展开更多
基金financial support from the China Postdoctoral Science Foundation(Grant No.2016M591853)the Foundation of the State Key Laboratory of Pulp and Paper Engineering,China(Grant No.201616)+1 种基金the Youth Science and Technology Innovation Fund of Nanjing Forestry University,China(CX2015015)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘In this study,wheat straw pulp was prepared by sulfiteformaldehyde(SF) pulping combined with oxygen delignification to develop a sustainable methodology for chemical pulping of straw materials.The bleachability of oxygen-delignified SF pulp was also evaluated by hypochlorite bleaching.The results indicated that the Na_2SO_3 charge played an important role in lignin removal during SF pulping as well as oxygen delignification.The efficiency of oxygen delignification of wheat straw SF pulp was markedly high.After the oxygenation stage,the Kappa number decreased by over 50%(the original Kappa number of SF pulp was lower than 30) when the Na OH charge was in the range of 3%~5%.The optimal conditions for preparing bleached pulp via combined SF pulping and oxygen delignification involved the use of 12% of Na_2SO_3 and 3% of Na OH,respectively.Pulp with relatively high brightness,a low Kappa number,as well as an acceptable viscosity could be obtained when oxygen-delignified SF pulp was bleached with hypochlorite under a low active chlorine dosage.
文摘Based on the on-site investigation and the principle of compressible flow, the working oxygen pressure should be matched to the Mach-number at the nozzle in designing nozzle and oxygen supply schedule so that the higher penetration depth and the more blending energy can be obtained for reducing energy loss by shock wave in the ultrasonic oxygen jet in the normal BOF steelmaking. For some special BOF blowing technologies, such as steelmaking with high phosphorus hot metal, post combustion oxygen lance, hot metal pretreatment, etc, the difference between working oxygen pressure and designed diffusion pressure which is related to Mach-number is necessary, so that the velocity of the oxygen jet will be decreased because of shock wave for expected metallurgical results.
文摘The analyses of water from four tributaries of Ikpa River: Afaha Nsai Stream (ANS), Ikot Ekpuk Stream (IES), Afaha Itam Stream(AIS) and Nduetong Stream (NDS) in International Telecommunication Union (ITU) Local Government Area of Akawa Ibom State in Nigeria were carried out using standard analytical procedures. The parameters investigated were temperature(Temp.), hydrogen ion concentration(pH), total suspended solids (TSS), total dissolved solids (TDS), dissolved oxygen (DO) and biochemical oxygen demand (BOD). Correlation analysis carried out between pairs of variables showed that only the correlation coefficients between TDS and DO in ANS( p <0.05); Temp. and TDS in IES ( p <0.05) and between Temp. and TDS in AIS ( p <0.01) were significant. None of the pairs of the variables in NDS showed any significant correlation. The coefficients of variation for the parameters were also computed and used in determining their stability in the water. The possible effects of these variables on each other and on the aquatic ecosystem were discussed.
文摘The purpose of this paper is to study the effect of oxygenate additives into gasoline for the improvement of physicochemical properties of blends.Methyl Tertiary Butyl Ether（MTBE）,Methanol,Tertiary butyl alcohol（TBA）,and Tertiary amyl alcohol（TAA） blend into unleaded gasoline with various blended rates of 2.5%,5%,7.5%,10%,15%,and 20%.Physicochemical properties of blends are analyzed by the standard American Society of Testing and Materials（ASTM） methods.Methanol,TBA,and TAA increase density of the mixtures,but MTBE decreases density.The addition of oxygenates lead to a distortion of the base gasoline＇s distillation curves.The Reid vapor pressure（RVP） of gasoline is found to increase with the addition of the oxygenated compounds.All oxygenates improve both motor and research octane numbers.Among these four additives,TBA shows the best fuel properties.
基金Project supported by the National Natural Science Foundation of China (No. 50674062)the Key Projects in the National Science & Technology Pillar Program (No. 2006BAC21B03)the Beijing Science and Technology Plan Projects of China (No. D07040300690000)
文摘A new method for estimating the degree of [SiO4]4-polymerization of coal gangue is presented. The method uses the relative bridging oxygen number (RBO) based on nuclear magnetic resonance (NMR) techniques. X-ray diffraction (XRD) and 29Si NMR techniques have been used to study phase transitions and silicate polymerization of coal gangue calcined at different temperatures or co-calcined. It has been found that phase transition of clay minerals causes silicate polymerization to change with temperature. In this study, cementing activity and RBO were determined to be inversely related. Generally, activated coal gangue with lower RBO had better cementitious activity.
