Based on the working of Lighthill and Hunt et al., in the present paper the author has established the topological rules adapting to analysing the skin-friction lines and the section streamlines in cascades. These rul...Based on the working of Lighthill and Hunt et al., in the present paper the author has established the topological rules adapting to analysing the skin-friction lines and the section streamlines in cascades. These rules are (1) for a rotor cascade without shroud band, the total number of nodal points equals that the saddle points on the skin-friction line vector fields in eachpitch range; (2) for an annular or straight cascade with no-clearances at blade ends, the total number of saddle points is two more than that of nodal points on the skin-friction line fields in a pitch; (3) the total number of saddles in the secondary flow fields on cross-sections in cascade is one less than that of nodes; (4) in the section streamline vector fields on a meridian surface penetrating a flow passage, and on leading and trailing edge sections, the total number of nodes is equal to that of saddles; (5) on the streamline vector fields of a blade-to-blade surface, the total number of nodes is one less than that of saddles.展开更多
The two-dimensional spreading under gravity of a thin fluid film with suction (fluid leak-off) or blowing (fluid injection) at the base is considered. The thin fluid film approximation is imposed. The height of the th...The two-dimensional spreading under gravity of a thin fluid film with suction (fluid leak-off) or blowing (fluid injection) at the base is considered. The thin fluid film approximation is imposed. The height of the thin film satisfies a nonlinear diffusion equation with a source/sink term. The Lie point symmetries of the nonlinear diffusion equation are derived and exist, which provided the fluid velocity at the base, <em>v<sub>n</sub></em> satisfies a first order linear partial differential equation. The general form has algebraic time dependence while a special case has exponential time dependence. The solution in which <em>v<sub>n</sub></em> is proportional to the height of the thin film is studied. The width of the base always increases with time even for suction while the height decreases with time for sufficiently weak blowing. The streamlines of the fluid flow inside the thin film are plotted by first solving a cubic equation. For sufficiently weak blowing there is a dividing streamline, emanating from the stagnation point on the centre line which separates the fluid flow into two regions, a lower region consisting of rising fluid and dominated by fluid injection at the base and an upper region consisting of descending fluid and dominated by spreading due to gravity. For sufficiently strong blowing the lower region expands to completely fill the whole thin film.展开更多
Multiply-connected Hall plates show different phenomena than singly connected Hall plates. In part I (published in Journal of Applied Physics and Mathematics), we discussed topologies where a stream function can be de...Multiply-connected Hall plates show different phenomena than singly connected Hall plates. In part I (published in Journal of Applied Physics and Mathematics), we discussed topologies where a stream function can be defined, with special reference to Hall/Anti-Hall bar configurations. In part II, we focus on topologies where no conventional stream function can be defined, like Corbino disks. If current is injected and extracted at different boundaries of a multiply-connected conductive region, the current density shows spiral streamlines at strong magnetic field. Spiral streamlines also appear in simply-connected Hall plates when current contacts are located in their interior instead of their boundary, particularly if the contacts are very small. Spiral streamlines and circulating current are studied for two complementary planar device geometries: either all boundaries are conducting or all boundaries are insulating. The latter case means point current contacts and it can be treated similarly to singly connected Hall plates with peripheral contacts through the definition of a so-called loop stream function. This function also establishes a relation between Hall plates with complementary boundary conditions. The theory is explained by examples.展开更多
The aim of this investigation is to determine the effect of fluid leak-off (suction) and fluid injection (blowing) at the horizontal base on the two-dimensional spreading under the gravity of a thin film of viscous in...The aim of this investigation is to determine the effect of fluid leak-off (suction) and fluid injection (blowing) at the horizontal base on the two-dimensional spreading under the gravity of a thin film of viscous incompressible fluid by studying the evolution of the streamlines in the thin film. It is assumed that the normal component of the fluid velocity at the base is proportional to the spatial gradient of the height of the film. Lie symmetry methods for partial differential equations are applied. The invariant solution for the surface profile is derived. It is found that the thin fluid film approximation is satisfied for weak to moderate leak-off and for the whole range of fluid injection. The streamlines are derived and plotted by solving a cubic equation numerically. For fluid injection, there is a dividing streamline originating at the stagnation point at the base which separates the flow into two regions, a lower region consisting mainly of rising fluid and an upper region consisting mainly of descending fluid. An approximate analytical solution for the dividing streamline is derived. It generates an approximate V-shaped surface along the length of the two-dimensional film with the vertex of each section the stagnation point. It is concluded that the fluid flow inside the thin film can be visualised by plotting the streamlines. Other models relating the fluid velocity at the base to the height of the thin film can be expected to contain a dividing streamline originating at a stagnation point and dividing the flow into a lower region of rising fluid and an upper region of descending fluid.展开更多
Purpose – The volume of passenger traffic at metro transfer stations serves as a pivotal metric for theorchestration of crowd flow management. Given the intricacies of crowd dynamics within these stations andthe recu...Purpose – The volume of passenger traffic at metro transfer stations serves as a pivotal metric for theorchestration of crowd flow management. Given the intricacies of crowd dynamics within these stations andthe recurrent instances of substantial passenger influxes, a methodology predicated on stochastic processesand the principle of user equilibrium is introduced to facilitate real-time traffic flow estimation within transferstation streamlines.Design/methodology/approach – The synthesis of stochastic process theory with streamline analysisengenders a probabilistic model of intra-station pedestrian traffic dynamics. Leveraging real-time passengerflow data procured from monitoring systems within the transfer station, a gradient descent optimizationtechnique is employed to minimize the cost function, thereby deducing the dynamic distribution of categorizedpassenger flows. Subsequently, adhering to the tenets of user equilibrium, the Frank–Wolfe algorithm isimplemented to allocate the intra-station categorized passenger flows across various streamlines, ascertainingthe traffic volume for each.Findings – Utilizing the Xiaozhai Station of the Xi’an Metro as a case study, the Anylogic simulation softwareis engaged to emulate the intra-station crowd dynamics, thereby substantiating the efficacy of the proposedpassenger flow estimation model. The derived solutions are instrumental in formulating a crowd controlstrategy for Xiaozhai Station during the peak interval from 17:30 to 18:00 on a designated day, yielding crowdmanagement interventions that offer insights for the orchestration of passenger flow and operationalgovernance within metro stations.Originality/value – The construction of an estimation methodology for the real-time streamline traffic flowaugments the model’s dataset, supplanting estimated values derived from surveys or historical datasets withreal-time computed traffic data, thereby enhancing the precision and immediacy of crowd flow managementwithin metro stations.展开更多
Using the satellite altimeter data from 1993 to 2021,this study investigates the seasonal and interannual variations of Kuroshio surface water intrusion into the East China Sea(ECS)with an emphasis on transports acros...Using the satellite altimeter data from 1993 to 2021,this study investigates the seasonal and interannual variations of Kuroshio surface water intrusion into the East China Sea(ECS)with an emphasis on transports across different isobaths.The results reveal that the intrusion variability differs among the isobaths used to identify the intrusion.On the seasonal scale,the transport volume and proportion of intrusion into the outer shelf(across 200 m isobath)are greatest in spring compared to other seasons possibly because of the relief of northerly monsoon and the increase of Kuroshio transport.However,in the inner shelf regions(across 100 m isobath),the strongest intrusion occurs in summer,with a much longer residence period and broader spatial range,though the Kuroshio moves farthest away from the coast.This implies that the Kuroshio may have the highest exchange efficiency with the ECS shelf water during summer.On the interannual scale,increased upstream transport from the Kuroshio and shoreward movement of the current almost equally contribute to the enhancement of surface water intrusion into the outer shelf regions.In contrast to the seasonal characteristics,the interannual intrusion into the shallower shelf regions(across the 120 m and 100 m isobaths)is primarily correlated to the position of the Kuroshio axis,i.e.,the closer to the coast the Kuroshio is,the more water can enter the inner continental shelf.This result highlights that the importance of factors that control the intrusion variabilities may also change between seasonal and interannual time scales when different isobaths are used.展开更多
The unsteady magnetohydrodynamical(MHD)free convection flow of an incompressible,electrically conducting hybrid nanofluid within a vertical cylindrical geometry is investigated,incorporating the effects of thermal rad...The unsteady magnetohydrodynamical(MHD)free convection flow of an incompressible,electrically conducting hybrid nanofluid within a vertical cylindrical geometry is investigated,incorporating the effects of thermal radiation,viscous dissipation,and internal heat generation.The system is subjected to a time-periodic boundary temperature condition.The Laplace and finite Hankel transforms are used to derive the exact solutions for the velocity and temperature distributions.The effects of various key physical parameters,including the Richardson number,the Eckert number,the radiation parameter,the heat source parameter,and the nanoparticle volume fraction,are considered.The numerical results reveal that increasing the volume fraction significantly enhances the thermal conductivity and temperature,while the magnetic field intensity and viscous dissipation strongly influence the fluid motion and heat transport.Additionally,the pulsating boundary conditions produce distinct oscillatory behaviors in both the velocity and temperature fields.These findings provide important insights into optimizing the heat transfer performance in cylindrical systems such as electronic cooling modules and energy storage devices operating under dynamic thermal conditions.展开更多
Tree knots are generally considered defects in wood,but how the surrounding structures of the defects affects strength of wood has not been studied.Here the mechanical properties of static compression and hole bearing...Tree knots are generally considered defects in wood,but how the surrounding structures of the defects affects strength of wood has not been studied.Here the mechanical properties of static compression and hole bearing tests were designed for encased knots and intergrown knots,and the strengthening mechanism of streamline tissue and connecting interface was analyzed by finite element modeling.And the two reinforced structures were applied to composite structural holes and connecting holes,which significantly improved open hole compressive strength and hole bearing strength.And the finite element models for two kinds of composite hole were created to analyze how the stress field around the reinforced structure strengthens the composite.Both the experimental results and the finite analysis results show that the streamline structure could effectively improve the compressive properties of composite structural holes,and the connecting interface provided a stable constraint for giving full play to the hole bearing properties of stronger materials.These two structures will provide reference for the structural design of lightweight composites.展开更多
Bathed in the golden light of September,Beijing’s Shougang Park hosted the 2025 China International Fair for Trade in Services(CIFTIS).At the heart of the event,a dynamic spirit of renewal was evident,as emerging pat...Bathed in the golden light of September,Beijing’s Shougang Park hosted the 2025 China International Fair for Trade in Services(CIFTIS).At the heart of the event,a dynamic spirit of renewal was evident,as emerging patterns in cultural,tourism,and sports consumption unfolded throughout the fair.From the creative integration of the centuries-old Peking Opera with innovative business models,to immersive sports experiences and the rollout of streamlined tax refund procedures for international visitors,the fair showcased a nuanced yet significant shift in consumption practices.展开更多
Streamlined box girders serve as a prevalent choice for the primary structural elements in large-span suspension bridge designs.With the increase in traffic demands,the design of such girders is evolving towards wider...Streamlined box girders serve as a prevalent choice for the primary structural elements in large-span suspension bridge designs.With the increase in traffic demands,the design of such girders is evolving towards wider bridge decks and larger aspect ratios(B/D).To obtain more effective and aerodynamic design shapes for streamlined box girders,it is essential to investigate the impact of B/D on their aerodynamic performance.Accordingly,in this study we investigate the buffeting responses of large-span suspension bridges using girders of varying aspect ratios(B/D of 7.5,9.3,and 12.7).First,the aerodynamic coefficients of these girders are estimated using computational fluid dynamics(CFD)simulations.Subsequently,spatial finite element(FE)models of three long-span suspension bridges with different girders(B/D of 7.5,9.3,and 12.7)are established in Ansys software,and the dynamic characteristics of these bridges are obtained.Then,the time-domain buffeting analysis is performed by simulating the fluctuating wind fields acting on the bridge through the spectral representation method.Ultimately,the buffeting responses are computed using Ansys software,and the impact of B/D on these responses is assessed.The results reveal that the root mean square(RMS)values of the main girder’s buffeting displacement are highest at the midspan position and are lowest at the ends of the bridge.A decrease in B/D of the main girder leads to a more severe buffeting response because both the range and the effective value of the displacement increase with the decreasing B/D.Comparing the buffeting displacements in three directions,B/D plays a significant role in the vertical buffeting displacement,moderately impacts the torsional displacement,and has the least effect on the lateral displacement.The findings of this study may help wind resistance analysis and design optimization for bridges.展开更多
AIM:To evaluate the one-year clinical outcomes of a novel canaloplasty device used in combination with cataract extraction(CE)in patients with mild to severe open angle glaucoma(OAG).METHODS:This study reviewed patien...AIM:To evaluate the one-year clinical outcomes of a novel canaloplasty device used in combination with cataract extraction(CE)in patients with mild to severe open angle glaucoma(OAG).METHODS:This study reviewed patients diagnosed with mild to severe OAG,who underwent canaloplasty with the STREAMLINE®Surgical System combined with CE.The primary outcome was surgical success,defined as achieving≥20%intraocular pressure(IOP)reduction and/or a reduction of≥1 glaucoma medication compared to baseline.Secondary outcomes included mean IOP,average number of glaucoma medications,and best-corrected distance visual acuity(BCDVA).Data was collected preoperatively and at multiple postoperative time points up to one year.RESULTS:A total of 68 eyes of 47 patients were included with mean age was 73.1±7.0y and 60%were females.Surgical success at one year was achieved in 68.8%of eyes,with 67.6%success in mild,80.0%in moderate,and 66.7%in severe OAG cases.IOP was significantly reduced from a baseline of 16.1±0.5 to 14.7±0.4 mm Hg at one year(P=0.0004).The number of medications decreased significantly in all eyes from a baseline of 1.2±0.1 to 0.6±0.1 at one year(P<0.0001).When stratified by glaucoma severity,only the mild group experienced a statistically significant decrease from a baseline of 1.1±0.1 to 0.4±0.1(P<0.0001).BCDVA improved significantly from baseline to one year.No sight-threatening complications were reported.CONCLUSION:Canaloplasty using the STREAMLINE®surgical system combined with CE effectively reduces IOP at one year in mild to severe OAG with minimal complications.IOP lowering efficacy,reduction in IOP lowering medications,and safety in moderate to severe OAG require further study.展开更多
R-phycoerythrin, a light-harvesting protein in some marine algae, and can be widely used in medicine, was isolated and purified from a red alga, Palmaria palmata (Lannaeus) Kuntze, using the streamline column (expande...R-phycoerythrin, a light-harvesting protein in some marine algae, and can be widely used in medicine, was isolated and purified from a red alga, Palmaria palmata (Lannaeus) Kuntze, using the streamline column (expanded bed adsorption) combined with ion-exchange chromatography. Because the crude extract was applied to the column upwardly, the column would not be blocked by polysaccharides usually very abundant in the extract of marine alga, this kind of blockage could hardly lie overcome in ordinary chromatographic column. After applying the crude extract containing 0.5 mol/L (NH4)(2)SO4, (NH4)(2)SO4 solution of different concentrations (0.2 mol/L, 0.1 mol/L and 0.05 mol/L) was used to elute the column downwardly and the eluates were collected and desalted. The desalted eluates were then applied onto all ion-exchange chromatographic column loaded with Q-sepharose for further purification of the R-phycoerythrin. Through these two steps, the purity (OD565/OD280) of the R-phycoerythrin from P. palmata was up to 3.5, more than 3.2, the commonly accepted criterion for purity, and the yield of the purified R-phycoerythrin could reach 0.122 mg/g of frozen P. palmata, much higher than that of phycobiliproteins purified with the previous methods. The result indicated that the cost of R-phycoerythrin will drop down with the method reported in this article.展开更多
Tapered ring with thin wall and three high ribs(TRTWTHR),showing complicated geometry(wall thickness is less than 4 mm and rib height exceeds 20 mm),is extensively utilized to fabricate the critical structural parts o...Tapered ring with thin wall and three high ribs(TRTWTHR),showing complicated geometry(wall thickness is less than 4 mm and rib height exceeds 20 mm),is extensively utilized to fabricate the critical structural parts of aerospace equipment such as spacecraft cabin,rocket body and fuel tank because of light weight and high carrying capacity.How to fabricate TRTWTHR with high performance is a critical problem that aerospace area needs to solve.In this work,constraining ring rolling(CRR)technique is first adopted to form TRTWTHR.However.unreasonable metal streamlines(UMS)and uncoordinated growth of three ribs easily occur in CRR of TRTWTHR,which makes the forming quality of TRTWTHR difficult to be controlled.Faced with this difficulty,an analytical model that can predict UMS and the height of three ribs in CRR of TRTWTHR is established so as to guide the process design of CRR.Subsequently,the reliability of the established analytical model and the feasibility of CRR of TRTWTHR are confirmed by FE simulation and experiment.Then,using the established analytical model,the window of UMS occurring relevant to the tapered angle of TRTWTHR and the location of the rib of middle end is developed.Finally,three uncoordinated growth modes among three ribs are found when the width of three ribs is identical and UMS do not occur,and the mechanisms of three uncoordinated growth modes are revealed.展开更多
Brazilian pre-salt reservoirs are renowned for their intricate pore networks and vuggy nature,posing significant challenges in modeling and simulating fluid flow within these carbonate reservoirs.Despite possessing ex...Brazilian pre-salt reservoirs are renowned for their intricate pore networks and vuggy nature,posing significant challenges in modeling and simulating fluid flow within these carbonate reservoirs.Despite possessing excellent petrophysical properties,such as high porosity and permeability,these reservoirs typically exhibit a notably low recovery factor,sometimes falling below 10%.Previous research has indicated that various enhanced oil recovery(EOR)methods,such as water alternating gas(WAG),can substantially augment the recovery factor in pre-salt reservoirs,resulting in improvements of up to 20%.Nevertheless,the fluid flow mechanism within Brazilian carbonate reservoirs,characterized by complex pore geometry,remains unclear.Our study examines the behavior of fluid flow in a similar heterogeneous porous material,utilizing a plug sample obtained from a vugular segment of a Brazilian stromatolite outcrop,known to share analogies with certain pre-salt reservoirs.We conducted single-phase and multi-phase core flooding experiments,complemented by medical-CT scanning,to generate flow streamlines and evaluate the efficiency of water flooding.Subsequently,micro-CT scanning of the core sample was performed,and two cross-sections from horizontal and vertical plates were constructed.These cross-sections were then employed as geometries in a numerical simulator,enabling us to investigate the impact of pore geometry on fluid flow.Analysis of the pore-scale modeling and experimental data unveiled that the presence of dead-end pores and vugs results in a significant portion of the fluid remaining stagnant within these regions.Consequently,the injected fluid exhibits channeling-like behavior,leading to rapid breakthrough and low areal swept efficiency.Additionally,the numerical simulation results demonstrated that,irrespective of the size of the dead-end regions,the pressure variation within the dead-end vugs and pores is negligible.Despite the stromatolite's favorable petrophysical properties,including relatively high porosity and permeability,as well as the presence of interconnected large vugs,the recovery factor during water flooding remained low due to early breakthrough.These findings align with field data obtained from pre-salt reservoirs,providing an explanation for the observed low recovery factor during water flooding in such reservoirs.展开更多
Vortices that develop over intakes are a hazardous hydraulic phenomenon.In this study, a 3D model was developed to study the flow field in air-core vortices.This model is based on the spiral pattern of streamlines and...Vortices that develop over intakes are a hazardous hydraulic phenomenon.In this study, a 3D model was developed to study the flow field in air-core vortices.This model is based on the spiral pattern of streamlines and the analytical solution of the momentum and continuity equations for deriving the three components of velocity.The model provides equations for free surface profiles and 3D patterns of the streamlines.Moreover, a new relationship was suggested for calculating effective viscosity and its distribution across the vortex flow field.The performance of the proposed analytical model was compared with existing experimental data and the results of previous analytical models.The outcomes indicated that the proposed model could predict characteristics of the vortex flow with good accuracy.展开更多
文摘Based on the working of Lighthill and Hunt et al., in the present paper the author has established the topological rules adapting to analysing the skin-friction lines and the section streamlines in cascades. These rules are (1) for a rotor cascade without shroud band, the total number of nodal points equals that the saddle points on the skin-friction line vector fields in eachpitch range; (2) for an annular or straight cascade with no-clearances at blade ends, the total number of saddle points is two more than that of nodal points on the skin-friction line fields in a pitch; (3) the total number of saddles in the secondary flow fields on cross-sections in cascade is one less than that of nodes; (4) in the section streamline vector fields on a meridian surface penetrating a flow passage, and on leading and trailing edge sections, the total number of nodes is equal to that of saddles; (5) on the streamline vector fields of a blade-to-blade surface, the total number of nodes is one less than that of saddles.
文摘The two-dimensional spreading under gravity of a thin fluid film with suction (fluid leak-off) or blowing (fluid injection) at the base is considered. The thin fluid film approximation is imposed. The height of the thin film satisfies a nonlinear diffusion equation with a source/sink term. The Lie point symmetries of the nonlinear diffusion equation are derived and exist, which provided the fluid velocity at the base, <em>v<sub>n</sub></em> satisfies a first order linear partial differential equation. The general form has algebraic time dependence while a special case has exponential time dependence. The solution in which <em>v<sub>n</sub></em> is proportional to the height of the thin film is studied. The width of the base always increases with time even for suction while the height decreases with time for sufficiently weak blowing. The streamlines of the fluid flow inside the thin film are plotted by first solving a cubic equation. For sufficiently weak blowing there is a dividing streamline, emanating from the stagnation point on the centre line which separates the fluid flow into two regions, a lower region consisting of rising fluid and dominated by fluid injection at the base and an upper region consisting of descending fluid and dominated by spreading due to gravity. For sufficiently strong blowing the lower region expands to completely fill the whole thin film.
文摘Multiply-connected Hall plates show different phenomena than singly connected Hall plates. In part I (published in Journal of Applied Physics and Mathematics), we discussed topologies where a stream function can be defined, with special reference to Hall/Anti-Hall bar configurations. In part II, we focus on topologies where no conventional stream function can be defined, like Corbino disks. If current is injected and extracted at different boundaries of a multiply-connected conductive region, the current density shows spiral streamlines at strong magnetic field. Spiral streamlines also appear in simply-connected Hall plates when current contacts are located in their interior instead of their boundary, particularly if the contacts are very small. Spiral streamlines and circulating current are studied for two complementary planar device geometries: either all boundaries are conducting or all boundaries are insulating. The latter case means point current contacts and it can be treated similarly to singly connected Hall plates with peripheral contacts through the definition of a so-called loop stream function. This function also establishes a relation between Hall plates with complementary boundary conditions. The theory is explained by examples.
文摘The aim of this investigation is to determine the effect of fluid leak-off (suction) and fluid injection (blowing) at the horizontal base on the two-dimensional spreading under the gravity of a thin film of viscous incompressible fluid by studying the evolution of the streamlines in the thin film. It is assumed that the normal component of the fluid velocity at the base is proportional to the spatial gradient of the height of the film. Lie symmetry methods for partial differential equations are applied. The invariant solution for the surface profile is derived. It is found that the thin fluid film approximation is satisfied for weak to moderate leak-off and for the whole range of fluid injection. The streamlines are derived and plotted by solving a cubic equation numerically. For fluid injection, there is a dividing streamline originating at the stagnation point at the base which separates the flow into two regions, a lower region consisting mainly of rising fluid and an upper region consisting mainly of descending fluid. An approximate analytical solution for the dividing streamline is derived. It generates an approximate V-shaped surface along the length of the two-dimensional film with the vertex of each section the stagnation point. It is concluded that the fluid flow inside the thin film can be visualised by plotting the streamlines. Other models relating the fluid velocity at the base to the height of the thin film can be expected to contain a dividing streamline originating at a stagnation point and dividing the flow into a lower region of rising fluid and an upper region of descending fluid.
文摘Purpose – The volume of passenger traffic at metro transfer stations serves as a pivotal metric for theorchestration of crowd flow management. Given the intricacies of crowd dynamics within these stations andthe recurrent instances of substantial passenger influxes, a methodology predicated on stochastic processesand the principle of user equilibrium is introduced to facilitate real-time traffic flow estimation within transferstation streamlines.Design/methodology/approach – The synthesis of stochastic process theory with streamline analysisengenders a probabilistic model of intra-station pedestrian traffic dynamics. Leveraging real-time passengerflow data procured from monitoring systems within the transfer station, a gradient descent optimizationtechnique is employed to minimize the cost function, thereby deducing the dynamic distribution of categorizedpassenger flows. Subsequently, adhering to the tenets of user equilibrium, the Frank–Wolfe algorithm isimplemented to allocate the intra-station categorized passenger flows across various streamlines, ascertainingthe traffic volume for each.Findings – Utilizing the Xiaozhai Station of the Xi’an Metro as a case study, the Anylogic simulation softwareis engaged to emulate the intra-station crowd dynamics, thereby substantiating the efficacy of the proposedpassenger flow estimation model. The derived solutions are instrumental in formulating a crowd controlstrategy for Xiaozhai Station during the peak interval from 17:30 to 18:00 on a designated day, yielding crowdmanagement interventions that offer insights for the orchestration of passenger flow and operationalgovernance within metro stations.Originality/value – The construction of an estimation methodology for the real-time streamline traffic flowaugments the model’s dataset, supplanting estimated values derived from surveys or historical datasets withreal-time computed traffic data, thereby enhancing the precision and immediacy of crowd flow managementwithin metro stations.
基金The National Natural Science Foundation of China under contract No.42276003the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University under contract No.SL2021MS021.
文摘Using the satellite altimeter data from 1993 to 2021,this study investigates the seasonal and interannual variations of Kuroshio surface water intrusion into the East China Sea(ECS)with an emphasis on transports across different isobaths.The results reveal that the intrusion variability differs among the isobaths used to identify the intrusion.On the seasonal scale,the transport volume and proportion of intrusion into the outer shelf(across 200 m isobath)are greatest in spring compared to other seasons possibly because of the relief of northerly monsoon and the increase of Kuroshio transport.However,in the inner shelf regions(across 100 m isobath),the strongest intrusion occurs in summer,with a much longer residence period and broader spatial range,though the Kuroshio moves farthest away from the coast.This implies that the Kuroshio may have the highest exchange efficiency with the ECS shelf water during summer.On the interannual scale,increased upstream transport from the Kuroshio and shoreward movement of the current almost equally contribute to the enhancement of surface water intrusion into the outer shelf regions.In contrast to the seasonal characteristics,the interannual intrusion into the shallower shelf regions(across the 120 m and 100 m isobaths)is primarily correlated to the position of the Kuroshio axis,i.e.,the closer to the coast the Kuroshio is,the more water can enter the inner continental shelf.This result highlights that the importance of factors that control the intrusion variabilities may also change between seasonal and interannual time scales when different isobaths are used.
基金Project supported by the National Natural Science Foundation of China(No.12250410244)the Jiangsu Funding Program for Excellent Postdoctoral Talent of China(No.2023ZB884)+2 种基金the Foreign Expert Project funding of China(No.WGXZ2023017L)the Shuang-Chuang(SC)Doctor Program of Jiangsu Provincethe Longshan Scholar Program of Nanjing University of Information Science&Technology。
文摘The unsteady magnetohydrodynamical(MHD)free convection flow of an incompressible,electrically conducting hybrid nanofluid within a vertical cylindrical geometry is investigated,incorporating the effects of thermal radiation,viscous dissipation,and internal heat generation.The system is subjected to a time-periodic boundary temperature condition.The Laplace and finite Hankel transforms are used to derive the exact solutions for the velocity and temperature distributions.The effects of various key physical parameters,including the Richardson number,the Eckert number,the radiation parameter,the heat source parameter,and the nanoparticle volume fraction,are considered.The numerical results reveal that increasing the volume fraction significantly enhances the thermal conductivity and temperature,while the magnetic field intensity and viscous dissipation strongly influence the fluid motion and heat transport.Additionally,the pulsating boundary conditions produce distinct oscillatory behaviors in both the velocity and temperature fields.These findings provide important insights into optimizing the heat transfer performance in cylindrical systems such as electronic cooling modules and energy storage devices operating under dynamic thermal conditions.
文摘Tree knots are generally considered defects in wood,but how the surrounding structures of the defects affects strength of wood has not been studied.Here the mechanical properties of static compression and hole bearing tests were designed for encased knots and intergrown knots,and the strengthening mechanism of streamline tissue and connecting interface was analyzed by finite element modeling.And the two reinforced structures were applied to composite structural holes and connecting holes,which significantly improved open hole compressive strength and hole bearing strength.And the finite element models for two kinds of composite hole were created to analyze how the stress field around the reinforced structure strengthens the composite.Both the experimental results and the finite analysis results show that the streamline structure could effectively improve the compressive properties of composite structural holes,and the connecting interface provided a stable constraint for giving full play to the hole bearing properties of stronger materials.These two structures will provide reference for the structural design of lightweight composites.
文摘Bathed in the golden light of September,Beijing’s Shougang Park hosted the 2025 China International Fair for Trade in Services(CIFTIS).At the heart of the event,a dynamic spirit of renewal was evident,as emerging patterns in cultural,tourism,and sports consumption unfolded throughout the fair.From the creative integration of the centuries-old Peking Opera with innovative business models,to immersive sports experiences and the rollout of streamlined tax refund procedures for international visitors,the fair showcased a nuanced yet significant shift in consumption practices.
基金funded by the National Natural Science Foundation of China(Grant No.52108435)the Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202404320)+1 种基金Chongqing Jiaotong University Postgraduate Research and Innovation Project(2024S0013)Chongqing Jiaotong University Undergraduate Innovation and Entrepreneurship Project(S202410618019).
文摘Streamlined box girders serve as a prevalent choice for the primary structural elements in large-span suspension bridge designs.With the increase in traffic demands,the design of such girders is evolving towards wider bridge decks and larger aspect ratios(B/D).To obtain more effective and aerodynamic design shapes for streamlined box girders,it is essential to investigate the impact of B/D on their aerodynamic performance.Accordingly,in this study we investigate the buffeting responses of large-span suspension bridges using girders of varying aspect ratios(B/D of 7.5,9.3,and 12.7).First,the aerodynamic coefficients of these girders are estimated using computational fluid dynamics(CFD)simulations.Subsequently,spatial finite element(FE)models of three long-span suspension bridges with different girders(B/D of 7.5,9.3,and 12.7)are established in Ansys software,and the dynamic characteristics of these bridges are obtained.Then,the time-domain buffeting analysis is performed by simulating the fluctuating wind fields acting on the bridge through the spectral representation method.Ultimately,the buffeting responses are computed using Ansys software,and the impact of B/D on these responses is assessed.The results reveal that the root mean square(RMS)values of the main girder’s buffeting displacement are highest at the midspan position and are lowest at the ends of the bridge.A decrease in B/D of the main girder leads to a more severe buffeting response because both the range and the effective value of the displacement increase with the decreasing B/D.Comparing the buffeting displacements in three directions,B/D plays a significant role in the vertical buffeting displacement,moderately impacts the torsional displacement,and has the least effect on the lateral displacement.The findings of this study may help wind resistance analysis and design optimization for bridges.
文摘AIM:To evaluate the one-year clinical outcomes of a novel canaloplasty device used in combination with cataract extraction(CE)in patients with mild to severe open angle glaucoma(OAG).METHODS:This study reviewed patients diagnosed with mild to severe OAG,who underwent canaloplasty with the STREAMLINE®Surgical System combined with CE.The primary outcome was surgical success,defined as achieving≥20%intraocular pressure(IOP)reduction and/or a reduction of≥1 glaucoma medication compared to baseline.Secondary outcomes included mean IOP,average number of glaucoma medications,and best-corrected distance visual acuity(BCDVA).Data was collected preoperatively and at multiple postoperative time points up to one year.RESULTS:A total of 68 eyes of 47 patients were included with mean age was 73.1±7.0y and 60%were females.Surgical success at one year was achieved in 68.8%of eyes,with 67.6%success in mild,80.0%in moderate,and 66.7%in severe OAG cases.IOP was significantly reduced from a baseline of 16.1±0.5 to 14.7±0.4 mm Hg at one year(P=0.0004).The number of medications decreased significantly in all eyes from a baseline of 1.2±0.1 to 0.6±0.1 at one year(P<0.0001).When stratified by glaucoma severity,only the mild group experienced a statistically significant decrease from a baseline of 1.1±0.1 to 0.4±0.1(P<0.0001).BCDVA improved significantly from baseline to one year.No sight-threatening complications were reported.CONCLUSION:Canaloplasty using the STREAMLINE®surgical system combined with CE effectively reduces IOP at one year in mild to severe OAG with minimal complications.IOP lowering efficacy,reduction in IOP lowering medications,and safety in moderate to severe OAG require further study.
文摘R-phycoerythrin, a light-harvesting protein in some marine algae, and can be widely used in medicine, was isolated and purified from a red alga, Palmaria palmata (Lannaeus) Kuntze, using the streamline column (expanded bed adsorption) combined with ion-exchange chromatography. Because the crude extract was applied to the column upwardly, the column would not be blocked by polysaccharides usually very abundant in the extract of marine alga, this kind of blockage could hardly lie overcome in ordinary chromatographic column. After applying the crude extract containing 0.5 mol/L (NH4)(2)SO4, (NH4)(2)SO4 solution of different concentrations (0.2 mol/L, 0.1 mol/L and 0.05 mol/L) was used to elute the column downwardly and the eluates were collected and desalted. The desalted eluates were then applied onto all ion-exchange chromatographic column loaded with Q-sepharose for further purification of the R-phycoerythrin. Through these two steps, the purity (OD565/OD280) of the R-phycoerythrin from P. palmata was up to 3.5, more than 3.2, the commonly accepted criterion for purity, and the yield of the purified R-phycoerythrin could reach 0.122 mg/g of frozen P. palmata, much higher than that of phycobiliproteins purified with the previous methods. The result indicated that the cost of R-phycoerythrin will drop down with the method reported in this article.
基金the National Natural Science Foundation of China (No. U2037204)the 111 Project (No. B17034)+1 种基金Innovative Research Team Development Program of Ministry of Education of China (No. IRT17R83)the National Natural Science Foundation of China (No. 52005375)
文摘Tapered ring with thin wall and three high ribs(TRTWTHR),showing complicated geometry(wall thickness is less than 4 mm and rib height exceeds 20 mm),is extensively utilized to fabricate the critical structural parts of aerospace equipment such as spacecraft cabin,rocket body and fuel tank because of light weight and high carrying capacity.How to fabricate TRTWTHR with high performance is a critical problem that aerospace area needs to solve.In this work,constraining ring rolling(CRR)technique is first adopted to form TRTWTHR.However.unreasonable metal streamlines(UMS)and uncoordinated growth of three ribs easily occur in CRR of TRTWTHR,which makes the forming quality of TRTWTHR difficult to be controlled.Faced with this difficulty,an analytical model that can predict UMS and the height of three ribs in CRR of TRTWTHR is established so as to guide the process design of CRR.Subsequently,the reliability of the established analytical model and the feasibility of CRR of TRTWTHR are confirmed by FE simulation and experiment.Then,using the established analytical model,the window of UMS occurring relevant to the tapered angle of TRTWTHR and the location of the rib of middle end is developed.Finally,three uncoordinated growth modes among three ribs are found when the width of three ribs is identical and UMS do not occur,and the mechanisms of three uncoordinated growth modes are revealed.
基金the support of EPIC-Energy Production Innovation Center,hosted by the University of Campinas(UNICAMP)sponsored by FAPESP-Sao Paulo Research Foundation(2017/15736e3 process).
文摘Brazilian pre-salt reservoirs are renowned for their intricate pore networks and vuggy nature,posing significant challenges in modeling and simulating fluid flow within these carbonate reservoirs.Despite possessing excellent petrophysical properties,such as high porosity and permeability,these reservoirs typically exhibit a notably low recovery factor,sometimes falling below 10%.Previous research has indicated that various enhanced oil recovery(EOR)methods,such as water alternating gas(WAG),can substantially augment the recovery factor in pre-salt reservoirs,resulting in improvements of up to 20%.Nevertheless,the fluid flow mechanism within Brazilian carbonate reservoirs,characterized by complex pore geometry,remains unclear.Our study examines the behavior of fluid flow in a similar heterogeneous porous material,utilizing a plug sample obtained from a vugular segment of a Brazilian stromatolite outcrop,known to share analogies with certain pre-salt reservoirs.We conducted single-phase and multi-phase core flooding experiments,complemented by medical-CT scanning,to generate flow streamlines and evaluate the efficiency of water flooding.Subsequently,micro-CT scanning of the core sample was performed,and two cross-sections from horizontal and vertical plates were constructed.These cross-sections were then employed as geometries in a numerical simulator,enabling us to investigate the impact of pore geometry on fluid flow.Analysis of the pore-scale modeling and experimental data unveiled that the presence of dead-end pores and vugs results in a significant portion of the fluid remaining stagnant within these regions.Consequently,the injected fluid exhibits channeling-like behavior,leading to rapid breakthrough and low areal swept efficiency.Additionally,the numerical simulation results demonstrated that,irrespective of the size of the dead-end regions,the pressure variation within the dead-end vugs and pores is negligible.Despite the stromatolite's favorable petrophysical properties,including relatively high porosity and permeability,as well as the presence of interconnected large vugs,the recovery factor during water flooding remained low due to early breakthrough.These findings align with field data obtained from pre-salt reservoirs,providing an explanation for the observed low recovery factor during water flooding in such reservoirs.
基金supported by the Iran National Science Foundation(INSF,Grant No.97008045)
文摘Vortices that develop over intakes are a hazardous hydraulic phenomenon.In this study, a 3D model was developed to study the flow field in air-core vortices.This model is based on the spiral pattern of streamlines and the analytical solution of the momentum and continuity equations for deriving the three components of velocity.The model provides equations for free surface profiles and 3D patterns of the streamlines.Moreover, a new relationship was suggested for calculating effective viscosity and its distribution across the vortex flow field.The performance of the proposed analytical model was compared with existing experimental data and the results of previous analytical models.The outcomes indicated that the proposed model could predict characteristics of the vortex flow with good accuracy.
