In this paper, a cost-benefit analysis based optimal planning model of battery energy storage system(BESS) in active distribution system(ADS) is established considering a new BESS operation strategy. Reliability impro...In this paper, a cost-benefit analysis based optimal planning model of battery energy storage system(BESS) in active distribution system(ADS) is established considering a new BESS operation strategy. Reliability improvement benefit of BESS is considered and a numerical calculation method based on expectation is proposed for simple and convenient calculation of system reliability improvement with BESS in planning phase. Decision variables include both configuration variables and operation strategy control variables. In order to prevent the interaction between two types of variables and enhance global search ability, intelligent single particle optimizer(ISPO) is adopted to optimize this model. Case studies on a modified IEEE benchmark system verified the performance of the proposed operation strategy and optimal planning model of BESS.展开更多
Strength and deformation behaviors of rockfill materials,key factors for determining the stability of dams,pertain strongly to the grain crushing characteristics.In this study,single-particle crushing tests were carri...Strength and deformation behaviors of rockfill materials,key factors for determining the stability of dams,pertain strongly to the grain crushing characteristics.In this study,single-particle crushing tests were carried out on rockfill materials with nominal particle diameters of 2.5 mm,5 mm and 10 mm to investigate the particle size effect on the single-particle strength and the relationship between the characteristic stress and probability of non-failure.Test data were found to be described by the Weibull distribution with the Weibull modulus of 3.24.Assemblies with uniform nominal grains were then subjected to one-dimensional compression tests at eight levels of vertical stress with a maximum of 100 MPa.The yield stress in one-dimensional compression tests increased with decreasing the particle size,which could be estimated from the single-particle crushing tests.The void ratio-vertical stress curve could be predicted by an exponential function.The particle size distribution curve increased obviously with applied stresses less than 16 MPa and gradually reached the ultimate fractal grading.The relative breakage index became constant with stress up to 64 MPa and was obtained from the ultimate grading at the fractal dimension(a?2:7).A hyperbolical function was also found useful for describing the relationship between the relative breakage index and input work during one-dimensional compression tests.展开更多
The Pb-monitoring program was extended for 6 years from 2002 to 2007 at 17 representative urban sites （6 traffic, 5 industrial, and 6 residential sites）, and 3 suburban sites to assess the lead pollution in fine par...The Pb-monitoring program was extended for 6 years from 2002 to 2007 at 17 representative urban sites （6 traffic, 5 industrial, and 6 residential sites）, and 3 suburban sites to assess the lead pollution in fine particulate matter （PM2.5） after phasing out leaded gasoline in Shanghai. Compared with Pb levels reported in other places, the Pb pollution in Shanghai is still serious after phasing out leaded gasoline, which remains at high concentration range （213-176 ng/m^3） in PM2.5 in winter. Significant spatial variation of Pb concentrations and strong seasonal variation of higher Pb concentration in winter than that in summer were detected. The size distribution of Pb in particulate matter has a unimodat mode that peaks at approximately 0.154-1.59 μm particle diameter, indicating that Pb is mainly concentrated in fine fraction. Lead in the fine fraction is enriched by a factor of 103-104 relative to Pb abundance in crust. Eight categories of Pb pollution sources were identified in the PM2.5 in the winter of 2007 in Shanghai. The important emission sources among them are vehicle exhaust derived from combustion of unleaded gasoline, metaUurgic industry emission, and coal combustion emission.展开更多
A virtual sieving experimental simulation system was built using physical simulation principles.The effects of vibration frequency and amplitude,the inclination angle of the screen-deck and the vibration direction ang...A virtual sieving experimental simulation system was built using physical simulation principles.The effects of vibration frequency and amplitude,the inclination angle of the screen-deck and the vibration direction angle of screen on single particle kinematics were predicted.Properties such as the average velocity and the average throw height were studied.The results show that the amplitude and the angle of vibration have a great effect on particle average velocity and average height.The vibration frequency and the screen-deck inclination angle appear to have little influence on these responses.For materials that are difficult to screen the vibration frequency and amplitude,the screen-deck inclination angle and the vibration angle should be set to 14 Hz,6.6 mm,6° and 40°,respectively,to obtain optimal particle kinematics.A screening process can be simulated reliably by means of a virtual experiment and these results provide references for both screening theory research and sieving practice.展开更多
The paths and sources of moisture supplied to South China during two periods of the presummer rainy season （April-June） of 1979-2014, i.e., before and after the onset of the summer monsoon over the South China Sea ...The paths and sources of moisture supplied to South China during two periods of the presummer rainy season （April-June） of 1979-2014, i.e., before and after the onset of the summer monsoon over the South China Sea （SCS）, are investigated by using the Hybrid Single-Particle Lagrangian Integrated Trajectory （HYSPLIT） model. During the premonsoon-onset period, the moisture transport trajectories are clustered into 6 groups, with four ocean-originating paths providing 83.9% and two continent-originating paths （originating over Lake Baikal and the Persian Gulf） con- tributing the remaining 16.1% of the total moisture. The two Pacific-originating paths, from the western Pacific Ocean and the East China Sea, combined account for about 46%, the SCS-originating path contributes about 24.3%, while the Bay of Bengal-originating path accounts for 13.6% of the total moisture over South China. The trajectories during the postmonsoon-onset period are clustered into 4 groups, with three southwesterly paths （from the Arabian Sea, the central Indian Ocean, and the western Indian Ocean, respectively） accounting for more than 76% and the sole Pacific-originating path accounting for 23.8% of the total moisture. The formation of the moisture transport tra-jectories is substantially affected by the topography, especially the Tibetan Plateau and the Indian and Indo-China Peninsulas. The SCS region contributes the most moisture during both periods （35.3% and 31.1%）. The Pacific Ocean is ranked second during the former period （about 21.0%） but its contribution is reduced to 5.0% during the lat-ter period, while the contribution from the Bay of Bengal and the Indian Ocean combined increases from 17.1% to 43.2%.展开更多
Co-combustion biomass and coal can effectively reduce the emission of CO_2. O_2/H_2O combustion is regarded as the next generation of oxy-fuel combustion technology. By co-combustion biomass and coal under oxy-fuel co...Co-combustion biomass and coal can effectively reduce the emission of CO_2. O_2/H_2O combustion is regarded as the next generation of oxy-fuel combustion technology. By co-combustion biomass and coal under oxy-fuel condition, the emission of CO_2 can be minimized. This work investigates the co-combustion characteristics of single particles from pine sawdust(PS) and bituminous coal(BC) in O_2/N2, O_2/CO_2 and O_2/H_2O atmospheres at different O_2 mole fractions(21%, 30% and 40%). The experiments were carried out in a drop tube furnace(DTF), and a high speed camera was used to record the combustion process of fuel particles. The combustion temperature was measured by a two-color method. The experiments in O_2/N2 atmosphere indicate that the particles from pine sawdust and bituminous coal all ignite homogeneously. After replacing H_2O for N2, the combustion temperature of volatiles of blended fuel particles decreases, while the combustion temperature of char increases. The ignition delay time in O_2/H_2O atmosphere is shorter than that in O_2/N2 or O_2/CO_2 atmosphere. The combustion temperature of volatiles of blended fuel particles increases as the mass fraction of bituminous coal increases, while the combustion temperature of char of blended fuel particles is higher than that of biomass or bituminous coal. The ignition delay time of blended fuel particles increases with the increasing mass fraction of bituminous coal, and the experimental ignition delay time of blend fuel particles is shorter than the theoretical one. These reveal a synergy during co-combustion process of pine sawdust and bituminous coal.展开更多
文摘In this paper, a cost-benefit analysis based optimal planning model of battery energy storage system(BESS) in active distribution system(ADS) is established considering a new BESS operation strategy. Reliability improvement benefit of BESS is considered and a numerical calculation method based on expectation is proposed for simple and convenient calculation of system reliability improvement with BESS in planning phase. Decision variables include both configuration variables and operation strategy control variables. In order to prevent the interaction between two types of variables and enhance global search ability, intelligent single particle optimizer(ISPO) is adopted to optimize this model. Case studies on a modified IEEE benchmark system verified the performance of the proposed operation strategy and optimal planning model of BESS.
基金financial support from the 111 Project (Grant No. B13024)the National Science Foundation of China (Grant Nos. 51509024, 51678094 and 51578096)+2 种基金the Fundamental Research Funds for the Central Universities (Grant No. 106112017CDJQJ208848)the Special Financial Grant from the China Postdoctoral Science Foundation (Grant No. 2017T100681)the State Key Laboratory for Geo Mechanics and Deep Underground Engineering, China University of Mining and Technology (Grant No. SKLGDUEK1810)
文摘Strength and deformation behaviors of rockfill materials,key factors for determining the stability of dams,pertain strongly to the grain crushing characteristics.In this study,single-particle crushing tests were carried out on rockfill materials with nominal particle diameters of 2.5 mm,5 mm and 10 mm to investigate the particle size effect on the single-particle strength and the relationship between the characteristic stress and probability of non-failure.Test data were found to be described by the Weibull distribution with the Weibull modulus of 3.24.Assemblies with uniform nominal grains were then subjected to one-dimensional compression tests at eight levels of vertical stress with a maximum of 100 MPa.The yield stress in one-dimensional compression tests increased with decreasing the particle size,which could be estimated from the single-particle crushing tests.The void ratio-vertical stress curve could be predicted by an exponential function.The particle size distribution curve increased obviously with applied stresses less than 16 MPa and gradually reached the ultimate fractal grading.The relative breakage index became constant with stress up to 64 MPa and was obtained from the ultimate grading at the fractal dimension(a?2:7).A hyperbolical function was also found useful for describing the relationship between the relative breakage index and input work during one-dimensional compression tests.
基金supported by the National Natural Sci-ence Foundation of China (No. 10775172, 10675159)the Major Project of Knowledge Innovation Program of Chinese Academy of Sciences (No.KJCX3.SYW.N3)This work has been performed under the approval of the Photon Factory (PF) Program Advisory Committee (No.2007G502)
文摘The Pb-monitoring program was extended for 6 years from 2002 to 2007 at 17 representative urban sites （6 traffic, 5 industrial, and 6 residential sites）, and 3 suburban sites to assess the lead pollution in fine particulate matter （PM2.5） after phasing out leaded gasoline in Shanghai. Compared with Pb levels reported in other places, the Pb pollution in Shanghai is still serious after phasing out leaded gasoline, which remains at high concentration range （213-176 ng/m^3） in PM2.5 in winter. Significant spatial variation of Pb concentrations and strong seasonal variation of higher Pb concentration in winter than that in summer were detected. The size distribution of Pb in particulate matter has a unimodat mode that peaks at approximately 0.154-1.59 μm particle diameter, indicating that Pb is mainly concentrated in fine fraction. Lead in the fine fraction is enriched by a factor of 103-104 relative to Pb abundance in crust. Eight categories of Pb pollution sources were identified in the PM2.5 in the winter of 2007 in Shanghai. The important emission sources among them are vehicle exhaust derived from combustion of unleaded gasoline, metaUurgic industry emission, and coal combustion emission.
基金support from the Innovative Research Groups of the National Natural Science Foundation of China (No.50921002)the National Natural Science Foundation of China (Nos.50574091 and 50774084)+1 种基金the "333 Project" Foundation of Jiangsu Provincethe Key Laboratory of Coal Processing & Efficient Utilization,Ministry of Education Foundation (No.CPEUKF 08-02) for this work
文摘A virtual sieving experimental simulation system was built using physical simulation principles.The effects of vibration frequency and amplitude,the inclination angle of the screen-deck and the vibration direction angle of screen on single particle kinematics were predicted.Properties such as the average velocity and the average throw height were studied.The results show that the amplitude and the angle of vibration have a great effect on particle average velocity and average height.The vibration frequency and the screen-deck inclination angle appear to have little influence on these responses.For materials that are difficult to screen the vibration frequency and amplitude,the screen-deck inclination angle and the vibration angle should be set to 14 Hz,6.6 mm,6° and 40°,respectively,to obtain optimal particle kinematics.A screening process can be simulated reliably by means of a virtual experiment and these results provide references for both screening theory research and sieving practice.
基金Supported by the National Natural Science Foundation of China(91437104 and 41775050)Basic Research and Operational Practice Funds of the Chinese Academy of Meteorological Sciences(2017Z006)
文摘The paths and sources of moisture supplied to South China during two periods of the presummer rainy season （April-June） of 1979-2014, i.e., before and after the onset of the summer monsoon over the South China Sea （SCS）, are investigated by using the Hybrid Single-Particle Lagrangian Integrated Trajectory （HYSPLIT） model. During the premonsoon-onset period, the moisture transport trajectories are clustered into 6 groups, with four ocean-originating paths providing 83.9% and two continent-originating paths （originating over Lake Baikal and the Persian Gulf） con- tributing the remaining 16.1% of the total moisture. The two Pacific-originating paths, from the western Pacific Ocean and the East China Sea, combined account for about 46%, the SCS-originating path contributes about 24.3%, while the Bay of Bengal-originating path accounts for 13.6% of the total moisture over South China. The trajectories during the postmonsoon-onset period are clustered into 4 groups, with three southwesterly paths （from the Arabian Sea, the central Indian Ocean, and the western Indian Ocean, respectively） accounting for more than 76% and the sole Pacific-originating path accounting for 23.8% of the total moisture. The formation of the moisture transport tra-jectories is substantially affected by the topography, especially the Tibetan Plateau and the Indian and Indo-China Peninsulas. The SCS region contributes the most moisture during both periods （35.3% and 31.1%）. The Pacific Ocean is ranked second during the former period （about 21.0%） but its contribution is reduced to 5.0% during the lat-ter period, while the contribution from the Bay of Bengal and the Indian Ocean combined increases from 17.1% to 43.2%.
基金supported by the National Natural Science Foundation of China(Grant Nos.51506091 and 51576100)the National Key R&D Program of China(Grant No.2016YFB0600100)the Fundamental Research Funds for the Central Universities(Grant No.30915011325)
文摘Co-combustion biomass and coal can effectively reduce the emission of CO_2. O_2/H_2O combustion is regarded as the next generation of oxy-fuel combustion technology. By co-combustion biomass and coal under oxy-fuel condition, the emission of CO_2 can be minimized. This work investigates the co-combustion characteristics of single particles from pine sawdust(PS) and bituminous coal(BC) in O_2/N2, O_2/CO_2 and O_2/H_2O atmospheres at different O_2 mole fractions(21%, 30% and 40%). The experiments were carried out in a drop tube furnace(DTF), and a high speed camera was used to record the combustion process of fuel particles. The combustion temperature was measured by a two-color method. The experiments in O_2/N2 atmosphere indicate that the particles from pine sawdust and bituminous coal all ignite homogeneously. After replacing H_2O for N2, the combustion temperature of volatiles of blended fuel particles decreases, while the combustion temperature of char increases. The ignition delay time in O_2/H_2O atmosphere is shorter than that in O_2/N2 or O_2/CO_2 atmosphere. The combustion temperature of volatiles of blended fuel particles increases as the mass fraction of bituminous coal increases, while the combustion temperature of char of blended fuel particles is higher than that of biomass or bituminous coal. The ignition delay time of blended fuel particles increases with the increasing mass fraction of bituminous coal, and the experimental ignition delay time of blend fuel particles is shorter than the theoretical one. These reveal a synergy during co-combustion process of pine sawdust and bituminous coal.
