ELD (economic load dispatch) problem is one of the essential issues in power system operation. The objective of solving ELD problem is to allocate the generation output of the committed generating units. The main co...ELD (economic load dispatch) problem is one of the essential issues in power system operation. The objective of solving ELD problem is to allocate the generation output of the committed generating units. The main contribution of this work is to solve the ELD problem concerned with daily load pattern. The proposed solution technique, developed based PSO (particle swarm optimization) algorithm, is applied to search for the optimal schedule of all generations units that can supply the required load demand at minimum fuel cost while satisfying all unit and system operational constraints. The performance of the developed methodology is demonstrated by case studies in test system of six-generation units. The results obtained from the PSO are compared to those achieved from other approaches, such as QP (quadratic programming), and GA (genetic algorithm).展开更多
Distribution system planners usually provide dedicated feeders to its different class of customers,each of whom has its own characteristic load pattern which varies hourly and seasonally.A more realistic modeling shou...Distribution system planners usually provide dedicated feeders to its different class of customers,each of whom has its own characteristic load pattern which varies hourly and seasonally.A more realistic modeling should be devised by considering the daily and seasonal variations in the aggregate load patterns of different class of customers.This paper addresses a new methodology to provide integrated solution for the optimal allocation of distributed generations and network reconfiguration considering load patterns of customers.The objectives considered are to maximize annual energy loss reduction and to maintain a better node voltage profile.Bat algorithm(BA)is a new bio-inspired search algorithm which has shown an advance capability to reach into the promising region,but its exploration is inadequate.The problem is solved by proposing the improved BA(IBA).The proposed method is investigated on the benchmark IEEE 33-bus test distribution system and the results are very promising.展开更多
[Objective] This study aimed to analyze the baking cost and benefit under different tobacco loading patterns, and to further explore labor-and cost-saving measures for modern tobacco agriculture. [Method] The cost and...[Objective] This study aimed to analyze the baking cost and benefit under different tobacco loading patterns, and to further explore labor-and cost-saving measures for modern tobacco agriculture. [Method] The cost and benefit of baking under three different tobacco loading patterns in a bulk curing barn were analyzed from the perspectives of baking equipment cost, labor cost, energy consumption and comprehensive income. The upper, middle and lower tobacco leaves were detected. [Result] Compared with conventional loading pattern, loose-leaf stacking and needle- style tobacco clip loading patterns significantly reduced the labor costs and energy costs during tobacco curing. The comprehensive benefits of tobacco clip and looseleaf stacking loading patterns were higher than that of conventional loading pattern, and the benefits of dry tobacco was improved by 0.67 and 1.07 yuan/kg, respec- tively. The benefit of loose-leaf stacking loading pattern was higher than that of to bacco clip loading pattern, [Conclusion] Among the three loading patterns, the loading pattern of loose-leaf stacking is most worthy of popularization and application.展开更多
The pinwheel pattern as a suitable and advantageous alternative for the loading implementation of the pallet loading problem (PLP) is identified after a survey on the loading pattern. The definitions, elements, cate...The pinwheel pattern as a suitable and advantageous alternative for the loading implementation of the pallet loading problem (PLP) is identified after a survey on the loading pattern. The definitions, elements, categories, generating algorithms of the pinwheel pattern are discussed and a uniform symmetric pinwheel notation is proposed. Based on the forming geometry of a pinwheel, the pinwheel structure is analyzed in terms of the innate box ratio, the box/block orientation and the box number by combinatorial and geometrical methods. A revised data set for the PLP with an area ratio range from 1 to 76 and a box ratio range from 1 to 10 is proposed. All pinwheel instances with this data set are calculated, and box ratio range is obtained for each possible pinwheel pattern, which can be found for all non-prime numbers of boxes. And a high box ratio makes an optimal pinwheel pattern more likely appear. Results identify the impact of the above pinwheel pattern and the box ratio on the pallet loading problem.展开更多
The seismic capacity curves of three types of buildings including frame,frame-shear wall and shear wall ob- tained by pushover analysis under different lateral load patterns are compared with those from nonlinear time...The seismic capacity curves of three types of buildings including frame,frame-shear wall and shear wall ob- tained by pushover analysis under different lateral load patterns are compared with those from nonlinear time history analy- sis.Based on the numerical results obtained a two-phase load pattern:an inverted triangle(first mode)load pattern until the base shear force reaches β times its maximum value,V_(max)followed by a(x/H)~α form,here β and α being some coeffi- cients depending on the type of the structures considered,is proposed in the paper,which can provide excellent approxima- tion of the seismic capacity curve for low-to-mid-rise shear type buildings.Furthermore,it is shown both the two-phase load pattern proposed and the invariant uniform pattern can be used for low-to-mid-rise shear-bending type and low-rise bending type of buildings.No suitable load patterns have been found for high-rise buildings.展开更多
Two calculation modes for the effect of external load on slope stability, i.e., mode I in which the external load is thought to act on slope surface, and mode II in which the external load is thought to act on slip su...Two calculation modes for the effect of external load on slope stability, i.e., mode I in which the external load is thought to act on slope surface, and mode II in which the external load is thought to act on slip surface along the force action line, were considered. Meanwhile, four basic distribution patterns of external load were used, of which complex external loads could be composed. In analysis process, several limit equilibrium methods, such as Swedish method, simplified Bishop method, simplified Janbu method, Spencer method, Morgenstern-Price(M-P) method, Sarma method, and unbalanced thrust method, were also adopted to contrast their differences in slope stability under the external load. According to parametric analysis, some conclusions can be obtained as follows:(1) The external load, with the large magnitude, small inclination angle, and acting position close to the slope toe,has more positive effect on slope stability;(2) The results calculated using modes I and II of external load are similar, indicating that the calculation mode of external load has little influence on slope stability;(3) If different patterns of external loads are equivalent to each other, their slope stability under these external loads are the same, and if not, the external load leads to the better slope stability,as action position of the resultant force for external load is closer to the lower sliding point of slip surface.展开更多
Molecular dynamics simulations are performed to study the nanoindentation models of monolayer suspended graphene and graphyne. Fullerenes are selected as indenters. Our results show that Young's modulus of monolayer-...Molecular dynamics simulations are performed to study the nanoindentation models of monolayer suspended graphene and graphyne. Fullerenes are selected as indenters. Our results show that Young's modulus of monolayer-thick graphyne is almost half of that of graphene, which is estimated to be 0.50 TPa. The mechanical properties of graphene and graphyne are different in the presence of strain. A pre-tension has an important effect on the mechanical properties of a membrane. Both the pre-tension and Young's modulus plots demonstrate index behavior. The toughness of graphyne is stronger than that of graphene due to Young's modulus magnitude. Young's moduli of graphene and graphyne are almost independent of the size ratio of indenter to membrane.展开更多
This paper presents a nonlinear approach to estimate the consumed energy in electric power distribution feeders. The proposed method uses the statistical solution algorithm to analyze the active energy monthly consump...This paper presents a nonlinear approach to estimate the consumed energy in electric power distribution feeders. The proposed method uses the statistical solution algorithm to analyze the active energy monthly consumption, which enables one to estimate the energy consumption during any period of the year. The energy readings and the normalized accumulated energy profile are used to estimate the hourly consumed active power, which can be used for future planning and sizing the equipment of the electrical system. The effectiveness of the proposed method is demonstrated by comparing the simulated results with that of real measured data.展开更多
Based on the concept of stiffness degradation, a damage index of the whole frame and the storey is proposed for the frame seismic performance evaluation. The index is compatible with the non-linear static analysis (e...Based on the concept of stiffness degradation, a damage index of the whole frame and the storey is proposed for the frame seismic performance evaluation. The index is compatible with the non-linear static analysis (e. g. the pushover analysis), and the structural damage is considered via plastic hinges. Simultaneously, a practical approach is developed to obtain the relationships between the proposed index and earthquake intensities based on the capacity spectrum method. The proposed index is then illustrated through two low-rise reinforced concrete frames, and it is also compared with some other indices. The results indicate that the proposed index is on the safe side and not sensitive to the lateral load pattern. The storey index is helpful to reflect the storey damage and to uncover the position of the weak storey. Finally, the relationship between performance levels and damage index values is also proposed through statistical analysis for the performance-based seismic evaluation.展开更多
Fast walking and jogging are two common exercises for people to maintain health in daily life.But the differences in loading patterns of fast walking and jogging are still unclear.The purpose of this study was to comp...Fast walking and jogging are two common exercises for people to maintain health in daily life.But the differences in loading patterns of fast walking and jogging are still unclear.The purpose of this study was to compare loading patterns in fast walking and jogging at the same speed,and to identify how differences in foot mechanics influence plantar pressure distribution between the two modes of gait.Totally,49 healthy males participated in this study.Data of pressure parameters,including maximum force(MF),peak pressure(PP),contact area(CA),force-time integral(FTI),were recorded by Pedar-X insole plantar pressure measurement system in participants’fast walking and jogging process at 7 km/h.A Load transfer analysis method was used to quantify the plantar load transference from fast walking to jogging.The results showed that MF,PP and CA increased in metatarsal regions and midfoot regions while decreased in toes regions and heel during jogging when compared with fast walking.FTI decreased in all foot regions during jogging compared to fast walking.Under the effects of spring mechanics and the varus of rearfoot during jogging,fast walking and jogging reveal different loading patterns.Compared jogging to fast walking,load transferred as follow:1)in transverse direction,load transferred from lateral foot to medial foot in metatarsal regions and midfoot regions,2)in longitudinal direction,load transferred from toes to the metatarsal,and from heel to the metatarsal and midfoot.These results also provide suggestions for footwear designs.展开更多
This paper presents the results of an ongoing investigation into transient pressure pulses using Shan- non entropy. Pressure fluctuations (produced by gas-solid two-phase flow during fluidized dense-phase conveying)...This paper presents the results of an ongoing investigation into transient pressure pulses using Shan- non entropy. Pressure fluctuations (produced by gas-solid two-phase flow during fluidized dense-phase conveying) are recorded by pressure transducers installed at strategic locations along a pipeline. This work validates previous work on identifying the flow mode from pressure signals (Mittal, Mallick, & Wypych, 2014). Two different powders, namely fly ash (median particle diameter 45 μm, particle den- sity 1950 kg/m3. loosely poured bulk density 950 kg/m3) and cement (median particle diameter 15 p,m, particle density 3060 kg/m3, loosely poured bulk density 1070 kg/m3), are conveyed through different pipelines (51 mm I.D. × 70 m length and 63 mm I.D. × 24 m length). The transient nature of pressure fluc- tuations (instead of steady-state behavior) is considered in investigating flow characteristics. Shannon entropy is found to increase along straight pipe sections for both solids and both pipelines. However, Shannon entropy decreases after a bend. A comparison of Shannon entropy among different ranges of superficial air velocity reveals that high Shannon entropy corresponds to very low velocities (i.e. 3-5 m/s) and very high velocities (i.e. 11-14 m/s) while low Shannon entropy corresponds to mid-range velocities (i.e. 6-8 m/s).展开更多
文摘ELD (economic load dispatch) problem is one of the essential issues in power system operation. The objective of solving ELD problem is to allocate the generation output of the committed generating units. The main contribution of this work is to solve the ELD problem concerned with daily load pattern. The proposed solution technique, developed based PSO (particle swarm optimization) algorithm, is applied to search for the optimal schedule of all generations units that can supply the required load demand at minimum fuel cost while satisfying all unit and system operational constraints. The performance of the developed methodology is demonstrated by case studies in test system of six-generation units. The results obtained from the PSO are compared to those achieved from other approaches, such as QP (quadratic programming), and GA (genetic algorithm).
文摘Distribution system planners usually provide dedicated feeders to its different class of customers,each of whom has its own characteristic load pattern which varies hourly and seasonally.A more realistic modeling should be devised by considering the daily and seasonal variations in the aggregate load patterns of different class of customers.This paper addresses a new methodology to provide integrated solution for the optimal allocation of distributed generations and network reconfiguration considering load patterns of customers.The objectives considered are to maximize annual energy loss reduction and to maintain a better node voltage profile.Bat algorithm(BA)is a new bio-inspired search algorithm which has shown an advance capability to reach into the promising region,but its exploration is inadequate.The problem is solved by proposing the improved BA(IBA).The proposed method is investigated on the benchmark IEEE 33-bus test distribution system and the results are very promising.
文摘[Objective] This study aimed to analyze the baking cost and benefit under different tobacco loading patterns, and to further explore labor-and cost-saving measures for modern tobacco agriculture. [Method] The cost and benefit of baking under three different tobacco loading patterns in a bulk curing barn were analyzed from the perspectives of baking equipment cost, labor cost, energy consumption and comprehensive income. The upper, middle and lower tobacco leaves were detected. [Result] Compared with conventional loading pattern, loose-leaf stacking and needle- style tobacco clip loading patterns significantly reduced the labor costs and energy costs during tobacco curing. The comprehensive benefits of tobacco clip and looseleaf stacking loading patterns were higher than that of conventional loading pattern, and the benefits of dry tobacco was improved by 0.67 and 1.07 yuan/kg, respec- tively. The benefit of loose-leaf stacking loading pattern was higher than that of to bacco clip loading pattern, [Conclusion] Among the three loading patterns, the loading pattern of loose-leaf stacking is most worthy of popularization and application.
基金The National Natural Science Foundation of China(No.70571033,70831002)
文摘The pinwheel pattern as a suitable and advantageous alternative for the loading implementation of the pallet loading problem (PLP) is identified after a survey on the loading pattern. The definitions, elements, categories, generating algorithms of the pinwheel pattern are discussed and a uniform symmetric pinwheel notation is proposed. Based on the forming geometry of a pinwheel, the pinwheel structure is analyzed in terms of the innate box ratio, the box/block orientation and the box number by combinatorial and geometrical methods. A revised data set for the PLP with an area ratio range from 1 to 76 and a box ratio range from 1 to 10 is proposed. All pinwheel instances with this data set are calculated, and box ratio range is obtained for each possible pinwheel pattern, which can be found for all non-prime numbers of boxes. And a high box ratio makes an optimal pinwheel pattern more likely appear. Results identify the impact of the above pinwheel pattern and the box ratio on the pallet loading problem.
文摘The seismic capacity curves of three types of buildings including frame,frame-shear wall and shear wall ob- tained by pushover analysis under different lateral load patterns are compared with those from nonlinear time history analy- sis.Based on the numerical results obtained a two-phase load pattern:an inverted triangle(first mode)load pattern until the base shear force reaches β times its maximum value,V_(max)followed by a(x/H)~α form,here β and α being some coeffi- cients depending on the type of the structures considered,is proposed in the paper,which can provide excellent approxima- tion of the seismic capacity curve for low-to-mid-rise shear type buildings.Furthermore,it is shown both the two-phase load pattern proposed and the invariant uniform pattern can be used for low-to-mid-rise shear-bending type and low-rise bending type of buildings.No suitable load patterns have been found for high-rise buildings.
基金Project(2015M580702)supported by the China Postdoctoral Science FoundationProject(51608541)supported by the National Natural Science Foundation of ChinaProject(2014122006)supported by the Guizhou Provincial Department of Transportation Foundation,China
文摘Two calculation modes for the effect of external load on slope stability, i.e., mode I in which the external load is thought to act on slope surface, and mode II in which the external load is thought to act on slip surface along the force action line, were considered. Meanwhile, four basic distribution patterns of external load were used, of which complex external loads could be composed. In analysis process, several limit equilibrium methods, such as Swedish method, simplified Bishop method, simplified Janbu method, Spencer method, Morgenstern-Price(M-P) method, Sarma method, and unbalanced thrust method, were also adopted to contrast their differences in slope stability under the external load. According to parametric analysis, some conclusions can be obtained as follows:(1) The external load, with the large magnitude, small inclination angle, and acting position close to the slope toe,has more positive effect on slope stability;(2) The results calculated using modes I and II of external load are similar, indicating that the calculation mode of external load has little influence on slope stability;(3) If different patterns of external loads are equivalent to each other, their slope stability under these external loads are the same, and if not, the external load leads to the better slope stability,as action position of the resultant force for external load is closer to the lower sliding point of slip surface.
基金Supported by the National Natural Science Foundation of China under Grant No 11274262the Natural Science Foundation of Hunan Province under Grand No 14JJ2046the Program for Changjiang Scholars and Innovative Research Team in Universities under Grant No IRT13093
文摘Molecular dynamics simulations are performed to study the nanoindentation models of monolayer suspended graphene and graphyne. Fullerenes are selected as indenters. Our results show that Young's modulus of monolayer-thick graphyne is almost half of that of graphene, which is estimated to be 0.50 TPa. The mechanical properties of graphene and graphyne are different in the presence of strain. A pre-tension has an important effect on the mechanical properties of a membrane. Both the pre-tension and Young's modulus plots demonstrate index behavior. The toughness of graphyne is stronger than that of graphene due to Young's modulus magnitude. Young's moduli of graphene and graphyne are almost independent of the size ratio of indenter to membrane.
文摘This paper presents a nonlinear approach to estimate the consumed energy in electric power distribution feeders. The proposed method uses the statistical solution algorithm to analyze the active energy monthly consumption, which enables one to estimate the energy consumption during any period of the year. The energy readings and the normalized accumulated energy profile are used to estimate the hourly consumed active power, which can be used for future planning and sizing the equipment of the electrical system. The effectiveness of the proposed method is demonstrated by comparing the simulated results with that of real measured data.
基金The National Basic Research Program of China(973 Program)(No.2007CB714200)
文摘Based on the concept of stiffness degradation, a damage index of the whole frame and the storey is proposed for the frame seismic performance evaluation. The index is compatible with the non-linear static analysis (e. g. the pushover analysis), and the structural damage is considered via plastic hinges. Simultaneously, a practical approach is developed to obtain the relationships between the proposed index and earthquake intensities based on the capacity spectrum method. The proposed index is then illustrated through two low-rise reinforced concrete frames, and it is also compared with some other indices. The results indicate that the proposed index is on the safe side and not sensitive to the lateral load pattern. The storey index is helpful to reflect the storey damage and to uncover the position of the weak storey. Finally, the relationship between performance levels and damage index values is also proposed through statistical analysis for the performance-based seismic evaluation.
基金supported by National Natural Science Foundation of China,grant number:11502154.
文摘Fast walking and jogging are two common exercises for people to maintain health in daily life.But the differences in loading patterns of fast walking and jogging are still unclear.The purpose of this study was to compare loading patterns in fast walking and jogging at the same speed,and to identify how differences in foot mechanics influence plantar pressure distribution between the two modes of gait.Totally,49 healthy males participated in this study.Data of pressure parameters,including maximum force(MF),peak pressure(PP),contact area(CA),force-time integral(FTI),were recorded by Pedar-X insole plantar pressure measurement system in participants’fast walking and jogging process at 7 km/h.A Load transfer analysis method was used to quantify the plantar load transference from fast walking to jogging.The results showed that MF,PP and CA increased in metatarsal regions and midfoot regions while decreased in toes regions and heel during jogging when compared with fast walking.FTI decreased in all foot regions during jogging compared to fast walking.Under the effects of spring mechanics and the varus of rearfoot during jogging,fast walking and jogging reveal different loading patterns.Compared jogging to fast walking,load transferred as follow:1)in transverse direction,load transferred from lateral foot to medial foot in metatarsal regions and midfoot regions,2)in longitudinal direction,load transferred from toes to the metatarsal,and from heel to the metatarsal and midfoot.These results also provide suggestions for footwear designs.
文摘This paper presents the results of an ongoing investigation into transient pressure pulses using Shan- non entropy. Pressure fluctuations (produced by gas-solid two-phase flow during fluidized dense-phase conveying) are recorded by pressure transducers installed at strategic locations along a pipeline. This work validates previous work on identifying the flow mode from pressure signals (Mittal, Mallick, & Wypych, 2014). Two different powders, namely fly ash (median particle diameter 45 μm, particle den- sity 1950 kg/m3. loosely poured bulk density 950 kg/m3) and cement (median particle diameter 15 p,m, particle density 3060 kg/m3, loosely poured bulk density 1070 kg/m3), are conveyed through different pipelines (51 mm I.D. × 70 m length and 63 mm I.D. × 24 m length). The transient nature of pressure fluc- tuations (instead of steady-state behavior) is considered in investigating flow characteristics. Shannon entropy is found to increase along straight pipe sections for both solids and both pipelines. However, Shannon entropy decreases after a bend. A comparison of Shannon entropy among different ranges of superficial air velocity reveals that high Shannon entropy corresponds to very low velocities (i.e. 3-5 m/s) and very high velocities (i.e. 11-14 m/s) while low Shannon entropy corresponds to mid-range velocities (i.e. 6-8 m/s).