Hydrodynamic simulations of directed flow for light hadrons in Au+Au and isobarcollisions at √SNN=200 GeV

Using a(3+1)-D hydrodynamic model,CLVisc,we study the directed flow(vi)of light hadrons pro-duced in Au+Au,Ru+Ru,and Zr+Zr collisions at √SNN=200 GeV.The evolution of tilted energy density,pres-sure gradient,and radial flow along the x-direction is systematically investigated.The counter-clockwise tilt of the initial fireball is shown to be a vital source of directed flow for final light hadrons.A good description of directed flow is provided for light hadrons in central and mid-central Au+Au and isobar collisions at the RHIC.Our numeric-al results show a clear system size dependence for light hadron Vi across different collision systems.We further study the effect of nuclear structure on the directed flow and find that v1 for light hadrons is insensitive to nuclei with quadrupole deformation.

Influence of the symmetry energy on the balance energy of the directed flow

The influence of the density-dependent symmetry energy on the balance energy （Ebal） of directed flow from heavy ion collisions （HICs） at incident energies covered by INDRA and MSU experiments is studied, using the updated version of the ultra- relativistic quantum molecular dynamics （UrQMD） model, especially adapted to low-energy heavy ion collisions （HICs）. Four mass-symmetric reactions with total mass numbers between 192 and 394 are chosen for investigating the influence of the symmetry energy on the system-mass dependence of Eual. The results show that the uncertainty in the density dependence of the symmetry potential causes changes of Ebal of the order of several MeV, depending on the type of particle considered. The Ebal of neutrons from HICs is particularly sensitive to the density dependence of the symmetry potential energy, while the system-mass dependence of EbaI of Z = 1 particles is not.

Yield ratios and directed flows of light fragments from reactions induced by neutron-rich nuclei at intermediate energy

The yield ratios of neutron/proton and ^3H/^3He and the directed flow per nucleon for these projectile-like fragments at large impact parameters are studied for ^50Ca ＋ ^40Ca and ^50Cr ＋ ^40Ca for comparison at 50 MeV/u using the isospin-dependent quantum molecular dynamics（IQMD model.It is found that the yield ratios and the directed flows per nucleon are different for reactions induced by the neutron-rich nucleus ^50Ca and the stable isobaric nucleus ^50Cr,and depend on the hardness of the EOS.The ratios of neutron/proton and ^3H/^3He and the difference of directed flow per nucleon of neutron-proton are suggested to be possible observables to investigate the isospin effects.

Flow Direction Level Traffic Flow Prediction Based on a GCN-LSTM Combined Model

Traffic flow prediction plays an important role in intelligent transportation systems and is of great significance in the applications of traffic control and urban planning.Due to the complexity of road traffic flow data,traffic flow prediction has been one of the challenging tasks to fully exploit the spatiotemporal characteristics of roads to improve prediction accuracy.In this study,a combined flow direction level traffic flow prediction graph convolutional network(GCN)and long short-term memory(LSTM)model based on spatiotemporal characteristics is proposed.First,a GCN model is employed to capture the topological structure of the data graph and extract the spatial features of road networks.Additionally,due to the capability to handle long-term dependencies,the longterm memory is used to predict the time series of traffic flow and extract the time features.The proposed model is evaluated using real-world data,which are obtained from the intersection of Liuquan Road and Zhongrun Avenue in the Zibo High-Tech Zone of China.The results show that the developed combined GCNLSTM flow direction level traffic flow prediction model can perform better than the single models of the LSTM model and GCN model,and the combined ARIMA-LSTM model in traffic flow has a strong spatiotemporal correlation.

FLOW DIRECTION OF PIEZOELECTRIC PUMP WITH NOZZLE/DIFFUSER-ELEMENTS

The piezoelectric pump with nozzle/diffuser-elements, which oscillating formdiffering from regular volumetric reciprocating or rotating pumps because there arenozzle/diffuser-elements substituted for regular valves, is a new type pump whose actuator is apiezoelectric ceramal part with verse piezoelectric effect In recent year, piezoelectric pump ispaid increasing attention to because it is an ideal candidate in application in such area as medicalhealth, mechanical tools and micro-mechanism. The fundamental research on it, however, is still notmade through. Focuses on the phenomenon of different directions of flow among Germany pump, Chinesepump and Swiss pump, which are all fitted with nozzle/diffuser-elements, and analyzes the coneangle of nozzle/diffuser-elements based on the flow equation of valve-less piezoelectric pump withnozzle/diffuser-elements. As a result, the concepts of diffuser toss coefficient and losscoefficient are introduced to explain these phenomena, from which a discussion is given on theoptimization of the cone angle of nozzle/diffuser-element aiming at the maximum of pump flow.

Identifying ephemeral gullies from high-resolution images and DEMs using flow-directional detection

Ephemeral gullies,which are widely developed worldwide and threaten farmlands,have aroused a growing concern.Identifying and mapping gullies are generally considered prerequisites of gully erosion assessment.However,ephemeral gully mapping remains a challenge.In this study,we proposed a flow-directional detection for identifying ephemeral gullies from high-resolution images and digital elevation models(DEMs).Ephemeral gullies exhibit clear linear features in high-resolution images.An edge detection operator was initially used to identify linear features from high-resolution images.Then,according to gully erosion mechanism,the flow-directional detection was designed.Edge images obtained from edge detection and flow directions obtained from DEMs were used to implement the flow-directional detection that detects ephemeral gullies along the flow direction.Results from ten study areas in the Loess Plateau of China showed that ranges of precision,recall,and Fmeasure are 6 o.66%-90.47%,65.74%-94.98%,and63.10%-91.93%,respectively.The proposed method is flexible and can be used with various images and DEMs.However,analysis of the effect of DEM resolution and accuracy showed that DEM resolution only demonstrates a minor effect on the detection results.Conversely,DEM accuracy influences the detection result and is more important than the DEM resolution.The worse the vertical accuracy of DEM,the lower the performance of the flow-directional detection will be.This work is beneficial to research related to monitoring gully erosion and assessing soil loss.

Functional connectivity and information flow in cerebral motor regions of healthy people following finger movement training

BACKGROUND：Neuro-rehabilitative training has been shown to promote motor function recovery in stroke patients,although the underlying mechanisms have not been fully clarified.OBJECTIVE：To investigate the effects of finger movement training on functional connectivity and information flow direction in cerebral motor areas of healthy people using electroencephalogram （EEG）.DESIGN,TIME AND SETTING：A self-controlled,observational study was performed at the College of Life Science and Bioengineering,Beijing University of Technology between December 2008 and April 2009.PARTICIPANTS：Nineteen healthy adults,who seldom played musical instruments or keyboards,were included in the present study.METHODS：Specific finger movement training was performed,and all subjects were asked to separately press keys with their left or right hand fingers,according to instructions.The task comprised five sessions of test train test train-test.Thirty-six channel EEG signals were recorded in different test sessions prior to and after training.Data were statistically analyzed using one-way analysis of variance.MAIN OUTCOME MEASURES：The number of effective performances,correct ratio,average response time,average movement time,correlation coefficient between pairs of EEG channels,and information flow direction in motor regions were analyzed and compared between different training sessions.RESULTS：Motor function of all subjects was significantly improved in the third test comparedwith the first test （P〈 0.01）.More than 80% of connections were strengthened in the motor-related areas following two training sessions,in particular the primary motor regions under the C4 electrode.Compared to the first test,a greater amount of information flowed from the Cz and Fcz electrodes （corresponding to supplementary motor area） to the C4 electrode in the third test.CONCLUSION：Finger task training increased motor ability in subjects by strengthening connections and changing information flow in the motor areas.These results provided a greater understanding of the mechanisms involved in motor rehabilitation.

Comparison of two different methods for determining flow direction in catchment hydrological modeling

Digital elevation models （DEMs） are widely used to define the flow direction in distributed hydrological models for simulation of streamflow. In recent decades, numerous methods for flow direction determination have been applied successfully to mountainous regions. Nevertheless, some problems still exist when those methods are used for flat or gently sloped areas The present study reviews the conventional methods of determining flow direction for such landscapes and analyzes the problems of these methods. Two different methods of determining flow direction are discussed and were applied to the Xitiaoxi Catchment, located in the Taihu Basin in southern China, which has both mountainous and flat terrain. Both the agree method and the shortest path method use drainage networks derived from a remote sensing image to determine the correct location of the stream. The results indicate that the agree method provides a better fit with the DEM for the hilly region than the shortest path method. For the flat region where the flow has been diverted and rerouted by land managers, both methods require observation of the drainage network to determine the flow direction. In order to clarify the applicability of the two methods, both are employed in catchment hydrological models conceptually based on the Xinanjiang model and implemented with PCRaster. The simulation results show that both methods can be successfully applied in hydrological modeling. There are no evident differences in the modeled discharge when using the two methods at different spatial scales.

Fault Location Method for Overhead Feeders with Distributed Generation Units Based on Direct Load Flow Approach

This paper proposes a novel fault location method for overhead feeders,which is based on the direct load flow approach.The method is developed in the phase domain to effectively deal with unbalanced network conditions,while it can also handle any type of distributed generation(DG)units without requiring equivalent models.By utilizing the line series parameters and synchronized or unsynchronized voltage and current phasor measurements taken from the sources,the method reliably identifies the most probable faulty sections.With the aid of an index,the exact faulty section among the multiple candidates is determined.Extensive simulation studies for the IEEE 123-bus test feeder demonstrate that the proposed method accu-rately estimates the fault position under numerous short-circuit conditions with varying prefault system loading conditions,fault resistances,and measurement errors.The proposed method is promising for practical applications due to the limited number of required measurement devices as well as the short computation time.

Contribution of GIS to Hydromorphometric Characterization of the Nkoup Watershed(Nun Plain-Cameroon)

The Nkoup watershed(10°35’-10°47’E and 5°27’-5°42’N)is a volcanic zone situated in Nun Plain West Came­roon.The high fertility of the soils makes it a strategic agropastoral area where water resources are heavily exploited and used for several purposes.Due to human activities,soils and water resources are deteriorating,giving birth to wa­ter pollution and hydromorphological hazards.This work aims to determine the hydromorphometric parameters of the Nkoup watershed so that the data obtained help in the sustainable management of water resources and conservation of soil.To achieve this aim,various data were collected from DEM dataset derived from SRTM and processed in specia­lized software(QGIS and ArGIS).The simplified hydrological balance was calculated using the upstream approach.The Nkoup watershed has:Axial length L_(ax)=25.8 km,Axial Width W_(ax)=11.1 km,Perimeter P=132.6 km,Area A=173.7 km^(2),Average Altitude Ha=1726.3 m,Compactness Index Icomp=2.8,Relief ratio Rr=3.9 m/km,Circularity ratio Rc=0.1,Elongation ratio R=0.1,Drainage texture ratio Rt=0.6,Drainage density Dd=0.5 km/km^(2).Stream Frequency Fs=0.4,Channel Sinuosity Index CSI=0.8,Stream gradient Sg=0.6 and global slope Index Ig=6.8 m/km.The specific height Difference Ds=89.4 m shows moderate relief.The precipitation and evapotranspiration are unevenly distributed.With P=187.7 mm/an,ETP=953.4 mm/an,Q=4.2 m3/s,R=762.5 mm/an,ETR=832.3 mm/an and I=282.9 mm/an.The Nkoup,36.9 km long,has a sinuous aspect due to the low slope and the high CSI.The piezometric levels vary according to the seasons and the groundwater flow follows the N-S direction as surface flow.

Energy dependence for directed and elliptic flow in intermediate-energy heavy ion collisions

Differential and integrated directed flow and elliptic flow of light charged particles （z ≤ 2） are studied systematically for semi-central （b = 5 fm） 197Au＋197Au collisions at incident energies from 25 to 250 MeV/nucleon by the isospin-dependent quantum molecular dynamics model. The changes of directed and elliptic flow with incident energy reflect the dynamic competition between mean field and nucleon-nucleon collisions and also between collective rotation and expansion.

RIGID-PLASTIC MECHANICAL MODEL FOR THE FORGING METHOD WITH HORIZONTAL V-SHAPED ANVIL

In order to decrease the anisotropy of mechanical properties, the rigid-plastic mechanical model for the forging method with horizontal V-shaped anvil is presented. The forging method, through the change of anvils shape, is able to control fibrous tissue direction, to improve the anisotropy of mechanical properties of axial forgings, to realize uniform forging. Therefore, the forging method can overcome the defect that conventional forging methods produce. The mechanism of the forging method with horizontal V-shaped anvil and the process of metal deformation are analyzed. The agreement of theoretical analysis with experimental study verifies the fact that the forging method with horizontal V-shaped anvil can control effectively the mechanical properties of axial forgings.

Effect of forest thinning on hydrologic nitrate exports from a Nsaturated plantation

Although several studies have assessed the effects of thinning on water quality,including nitrogen(N)exports,few have examined N-saturated plantations.This study assessed the short-term effect of thinning on N exports from a N-saturated plantation forest in northern Kyushu,western Japan,that was thinned(43%of basal area)during January-March 2012.Water levels at the gauging station were continually measured,and streamwater baseflow and stormflow samples were collected before(2011)and after(2013)forest thinning.Annual precipitation before(2469 mm)and after(2418 mm)forest thinning differed little,and annual water discharge after thinning(1641 mm)was similar to that before thinning(1609 mm).However,direct flow during stormflow periods was higher after thinning(260 mm)than before(153 mm).The concentrations of major ions in stream water did not differ before and after thinning.As a result,the high annual dissolved inorganic N(DIN)exports differed little before(35.8 kg N ha^-1 a^-1)and after(36.5 kg N ha^-1 a^-1)forest thinning.DIN exports during stormflow periods were slightly higher after(12.2 kg N ha^-1 a^-1)than before thinning(10.5 kg N ha^-1 a^-1)and were proportional to the increased direct flow after thinning(561 mm after vs.470 mm before thinning).We concluded that thinning does not affect annual N exports from the N-saturated plantation forest,but it can increase the proportion of N exported during stormflow periods in proportion to increased water volume of direct flow after thinning.

Investigating the Prospect of Small-Scale Wind Turbines Based on Regional Wind Velocities in Bangladesh

The wind turbine has the advantage of operating uninterruptedly, which ensures a constant source of electricity. This investigation includes a clear overview of the wind velocity, the flow direction;the amount of energy reserved, suitable regions for wind turbine installation, etc. The feasibility and possibility of installing a wind energy conversion system for several locations in Bangladesh are analyzed. A brief study of wind characteristics in different locations in Bangladesh is reported. Wind data obtained from the Bangladesh Meteorological Department (BMD) for Mongla, Patuakhali, Kutubdia, and Bhola stations are analyzed through wind rose, frequency distribution, and average wind velocity. The performance of suitable small-scale wind turbines will be assessed in order to confirm the prospect of wind turbines in Bangladesh.

Characteristics and generation of elastic turbulence in a three-dimensional parallel plate channel using direct numerical simulation

Direct numerical simulations（DNSs） of purely elastic turbulence in rectilinear shear flows in a three-dimensional（3D） parallel plate channel were carried out,by which numerical databases were established.Based on the numerical databases,the present paper analyzed the structural and statistical characteristics of the elastic turbulence including flow patterns,the wall effect on the turbulent kinetic energy spectrum,and the local relationship between the flow motion and the microstructures＇ behavior.Moreover,to address the underlying physical mechanism of elastic turbulence,its generation was presented in terms of the global energy budget.The results showed that the flow structures in elastic turbulence were 3D with spatial scales on the order of the geometrical characteristic length,and vortex tubes were more likely to be embedded in the regions where the polymers were strongly stretched.In addition,the patterns of microstructures＇ elongation behave like a filament.From the results of the turbulent kinetic energy budget,it was found that the continuous energy releasing from the polymers into the main flow was the main source of the generation and maintenance of the elastic turbulent status.

Numerical Investigation on Characteristics of Supercritical CO_(2)Heat Transfer in Vertical Circular Tubes with Circumferentially Half-Side Heating

The design of heat exchangers in the advanced supercritical power conversion system cannot be separated from the study of heat transfer issues.Half-side heating mode is often encountered for solar receiver and supercritical boiler.Here,the characteristics of supercritical CO_(2)(sCO_(2))convection heat transfer in vertical tubes with circumferentially half-side heating was numerically investigated through the SST k-ωturbulent model which matches well with the experimental data.Then,heat transfer between sCO_(2)upflow and downflow was compared.Similar to film boiling heat transfer at subcritical pressure,numerical results were processed according to the supercritical pseudo-phase transition hypothesis,with liquid-like phase in the tube core region and vapor-like film in the region near the heated tube wall.The structure of two layers was demarcated by pseudo-critical temperature T_(pc).Therefore,sCO_(2)heat transfer was assessed according to double thermal resistances caused by vapor-like film near the wall and core liquid-like phase.The findings suggest that wall temperature for upflow is higher than that for downflow,which is attributed to larger thermal resistance in the fluid domain for upflow than that for downflow.The difference guarantees the excellent heat transfer performance for downflow than upflow.It is also further concluded that the formation of vapor-like film near the wall due to pseudo-phase transition plays a key role in dominating wall temperature and inducing heat transfer deterioration in half-side heating tubes.The present contribution is significant to the design of supercritical heat exchanger under half-side heating mode.

Anisotropic flow at RHIC

STAR’s measurement of directed flow for pions,kaons（K 0 S ）,protons and anti-protons,for Au＋Au collisions at 200 GeV obtained in Run7 are presented,as well as elliptic flow for identified particles measured in Au＋Au（Run7） and Cu＋Cu（Run5） collisions.It is found that the slope of proton v 1 （y） at midrapidity is extremely small.Elliptic flow results are compared to Hydro calculation and the discrepancy is discussed.

Wind-vehicle-bridge coupled vibration analysis based on random traffic flow simulation

A wind-vehicle-bridge system can be regarded as an interaction result of wind-bridge interaction, wind-vehicle interaction and vehicle-bridge interaction, which is determined by nature wind, dynamic characteristics of vehicle and bridge structures, interrelationship between bridge and vehicle dynamic properties and so on. Firstly, based on the traffic loading investigation on the expressway bridge within 24 hours a day, all the critical parameters of traffic flow, such as the vehicle type, weight, separation space and speed are all recorded and analyzed to extract its statistical characteristics, which are used to work out random traffic flow simulation program RTF. This RTF program can be embedded with the other general FEM software. Secondly, a dynamic analysis module RTFWVB of the wind-vehicle-bridge coupling vibration under random traffic flow is presented, which can consider arbitrary number of vehicles, multi-lanes and traffic flow direction. Finally, Hangzhou Bay Bridge in China is selected as a numerical example to demonstrate dynamic interaction of the RTFWVB system. The results indicate that the traffic flow direction has just a little influence on bridge dynamic response, that the mean responses are mainly determined by the moving vehicle loads, and that the fluctuating components will increase with the increase of wind speed.

YIELD SURFACES AND PLASTIC FLOW OF 45 STEEL UNDER TENSION-TORSION LOADING PATHS

An experimental analysis on the subsequent yield-surfaces evolution using multiple specimens is presented for a 45 steel after a prescribed pre-strain loading in three different directions respectively, and the yielding is defined by a designated offsetting strain. The size of the subsequent yield surface is found smaller than the initial yield surface; the negative cross effects are observed in the normal loading direction, its shape is not a Mises circle but has a rather blunt nose in loading direction and flat in the opposite. These results strongly depend on the loading path and the prescribed offset plastic strain. The plastic flow direction to the subsequent yield surface is investigated, and it is found that the plastic flow direction deviates from the normal flow rule. The deviation differs from preloading case to preloading case. And the plastic flow direction would have a larger deviation from the normal of the yield surface, if the subsequent yield was defined by a smaller offset strain. Furthermore, the experiments are simulated using the Chaboche model, and the results show that it can rationally predict yield-surface only when yield is defined by a fairly large offset strain.

Improvements to machining surface quality by controlling the flow direction of electrolyte during electrochemical sinking and milling of titanium alloy

Electrochemical milling is eminently suitable for machining aerospace parts(which usually have complex structures) because of its great flexibility. However,titanium alloys are particularly sensitive to changes in the flow field,which often cause severe pitting corrosion of the machined surface. Although electrochemical sinking and milling(ESM) can restrict the flow of electrolyte and reduce pitting corrosion,the quality of the machined surface is not ideal because the latter are susceptible to stray corrosion. To reduce such corrosion and improve the surface quality,the internal flow channel of the tool electrode and the cutting depth were investigated thoroughly. Extensive experiments revealed that stray corrosion could be reduced significantly and surface quality improved by controlling the electrolyte flow direction in the machining area,which was achieved by changing the style of the internal flow channel of the tool electrode. These reductions in corrosion and surface roughness were achieved using a tool electrode with a triangular internal flow channel. In addition,the main components and micro-hardness of the machined surface were close to that of the TB6 titanium alloy substrate,which helped to maintain the inherent high strength of the titanium alloy. The surface of the workpiece changed from being hydrophilic to being hydrophobic,which reduced the flow resistance.