生产井开发指标的分层分方向定量计算方法

针对注水开发的多层砂岩油藏分层动态分析难度大等问题,在常规井层开发指标计算基础上,结合动、静态劈分方法,综合考虑渗透率、孔隙度、地层系数、含水饱和度、位置系数、措施系数及注水量系数,提出了一种既可将油、水井作为统一整体,又可对小层、方向流动分量开发指标进行定量计算的体现渗流力学本质的方法。用大庆油田N2-O1井组的产液剖面资料进行验证。结果表明,所提方法的计算结果与测量结果吻合度较高,精度平均值达75.11%。用该方法计算开发指标,适用性强,能较真实地反映各小层、各方向的产液情况,对现场应用具有指导意义。

A Modified Groundwater Module in SWAT for Improved Streamflow Simulation in a Large, Arid Endorheic River Watershed in Northwest China

Interactions between surface water and groundwater are dynamic and complex in large endorheic river watersheds in Northwest China due to the influence of both irrigation practices and the local terrain. These interactions interchange numerous times throughout the middle reaches, making streamflow simulation a challenge in endorheic river watersheds. In this study, we modified the linear-reservoir groundwater module in SWAT(Soil and Water Assessment Tools, a widely used hydrological model) with a new nonlinear relationship to better represent groundwater processes; we then applied the original SWAT and modified SWAT to the Heihe River Watershed, the second largest endorheic river watershed in Northwest China, to simulate streamflow. After calibrating both the original SWAT model and the modified SWAT model, we analyzed model performance during two periods: an irrigation period and a non-irrigation period. Our results show that the modified SWAT model with the nonlinear groundwater module performed significantly better during both the irrigation and non-irrigation periods. Moreover, after comparing different runoff components simulated by the two models, the results show that, after the implementation of the new nonlinear groundwater module in SWAT, proportions of runoff components changed-and the groundwater flow had significantly increased, dominating the discharge season. Therefore, SWAT coupled with the non-linear groundwater module represents the complex hydrological process in the study area more realistically. Moreover, the results for various runoff components simulated by the modified SWAT models can be used to describe the hydrological characteristics of lowland areas. This indicates that the modified SWAT model is applicable to simulate complex hydrological process of arid endorheic rivers.

Effect of graphene on mechanical properties of cement mortars

Functionalized graphene nano-sheets(FGN) of 0.01%-0.05%(mass fraction) were added to produce FGN-cement composites in the form of mortars. Flow properties, mechanical properties and microstructure of the cementitious material were then investigated. The results indicate that the addition of FGN decreases the fluidity slightly and improves mechanical properties of cement-based composites significantly. The highest strength is obtained with FGN content of 0.02% where the flexural strength and compressive strength at 28 days are 12.917 MPa and 52.42 MPa, respectively. Besides, scanning electron micrographs show that FGN can regulate formation of massive compact cross-linking structures and thermo gravimetric analysis indicates that FGN can accelerate the hydration reaction to increase the function of the composite effectively.

Vector modeling of robotic helical milling hole movement and theoretical analysis on roughness of hole surface

To avoid the machine problems of excessive axial force, complex process flow and frequent tool changing during robotic drilling holes, a new hole-making technology (i.e., helical milling hole) was introduced for designing a new robotic helical milling hole system, which could further improve robotic hole-making ability in airplane digital assembly. After analysis on the characteristics of helical milling hole, advantages and limitations of two typical robotic helical milling hole systems were summarized. Then, vector model of helical milling hole movement was built on vector analysis method. Finally, surface roughness calculation formula was deduced according to the movement principle of helical milling hole, then the influence of main technological parameters on surface roughness was analyzed. Analysis shows that theoretical surface roughness of hole becomes poor with the increase of tool speed ratio and revolution radius. Meanwhile, the roughness decreases according to the increase of tool teeth number. The research contributes greatly to the construction of roughness prediction model in helical milling hole.

A robust system for real-time pedestrian detection and tracking

A real-time pedestrian detection and tracking system using a single video camera was developed to monitor pedestrians. This system contained six modules: video flow capture, pre-processing, movement detection, shadow removal, tracking, and object classification. The Gaussian mixture model was utilized to extract the moving object from an image sequence segmented by the mean-shift technique in the pre-processing module. Shadow removal was used to alleviate the negative impact of the shadow to the detected objects. A model-free method was adopted to identify pedestrians. The maximum and minimum integration methods were developed to integrate multiple cues into the mean-shift algorithm and the initial tracking iteration with the competent integrated probability distribution map for object tracking. A simple but effective algorithm was proposed to handle full occlusion cases. The system was tested using real traffic videos from different sites. The results of the test confirm that the system is reliable and has an overall accuracy of over 85%.

Relative Flow Analysis around Passing-Train in the Single-Bore Subway Tunnel with Vertical Ventilation Using Moving IBM

Moving IBM （immersed boundary method） is applied to analyze the relative motion of railway car flow in the single-bore subway tunnel with vertical ventilation. The tested car body is modeled by cylinder type body. The subway tunnel is assumed to be the single-car-passing straight type （single-bore tunnel）. The modeled car is relatively moved forward. On the other hand, the tunnel and vertical ventilation are fixed. The momentum equations are solved by LES （large eddy simulation） method. The initial condition of fluid in the subway tunnel is stationary. The Reynolds number is 1,500 based on the cylinder radius. The turbulent flow field in the subway tunnel and vertical ventilation shaft are to be qualitatively investigated.

Online measurement of solids motion in fluidized bed reactor with different distributor for Fischer–Tropsch synthesis

In this paper, the distributions of particle velocity in a gas–solid fluidized bed with branched pipe distributor or circle distributor were measured by using a laser Doppler velocimetry. Our results show that, within a certain range of superficial gas velocity, when using circle distributor, the particle velocity is large and the distribution of the particle velocity is even more compared with the branched pipe distributor. On the basis of the amplitude of tangential movement statistics, the amplitude of tangential movement statistics(AVATMS) decreases with increasing the axial height under the appropriate superficial gas velocity.

Computational analysis of the flow of pseudoplastic power-law fluids in a microchannel plate

The flow of pseudoplastic power-law fluids with different flow indexes at a microchannel plate was studied using computational fluid dynamic simulation.The velocity distribution along the microchannel plate and especially in the microchannel slits,flow pattern along the outlet arc and the pressure drop through the whole of microchannel plate were investigated at different power-law flow indexes.The results showed that the velocity profile in the microchannel slits for low flow index fluids was similar to the plug flow and had uniform pattern.Also the power-law fluids with lower flow indexes had lower stagnation zones near the outlet of the microchannel plate.The pressure drop through the microchannel plate showed huge differences between the fluids.The most interesting result was that the pressure drops for power-law fluids were very smaller than that of Newtonian fluids.In addition,the heat transfer of the fluids through the microchannel with different channel numbers in a wide range of Reynolds number was investigated.For power-law fluid with flow index(n=0.4),the Nusselt number increases continuously as the number of channels increases.The results highlight the potential use of using pseudoplastic fluids in the microheat exchangers which can lower the pressure drop and increase the heat transfer efficiency.

Development of the Interurban Service with the Use of Alternative Commercial Road Trains

The main task of this paper is to review the principal aspects in organization of interurban long haul service with the use of road trains on the basis of the ＂district＂ traffic system. The goal of the paper is to determine the most effective methods of trucking operations in order to highlight the regularities that characterize these methods. The paper describes practicable methods of freight flow analysis, some factors and parameters concerning movement of motor-vehicle trains and original route schedules as well. Of special interest is the obtained algorithm of economically effective trucking operations of motor-vehicle trains on the route.

Network Traffic Signature Generation Mechanism Using Principal Component Analysis

The Deep Packet Inspection(DPI)method is a popular method that can accurately identify the flow data and its corresponding application.Currently,the DPI method is widely used in common network management systems.However,the major limitation of DPI systems is that their signature library is mainly extracted manually,which makes it hard to efficiently obtain the signature of new applications.Hence,in this paper,we propose an automatic signature extraction mechanism using Principal Component Analysis(PCA)technology,which is able to extract the signature automatically.In the proposed method,the signatures are expressed in the form of serial consistent sequences constructed by principal components instead of normally separated substrings in the original data extracted from the traditional methods.Extensive experiments based on numerous sets of data have been carried out to evaluate the performance of the proposed scheme,and the results prove that the newly proposed method can achieve good performance in terms of accuracy and efficiency.

Experimental Noise Analysis of Reed Switch Sensor Signal under Environmental Vibration

The chattering noise problem of reed switch sensor signal for Automatic Meter Reading system was analyzed experimentally under various types of external vibrations and shocks. The external vibration level amplitude was measured with an accelerometer. To apply for water flow measurement devices, the reed switch sensors should keep high reliability. But the measured digital meter data are occurred difference or errors by chattering noise. The reed switch contains chattering error by itself at the force equivalent position. The vibrations such as passing vehicle near to the reed switch installed location causes chattering. In order to reduce chattering error, most system uses just software methods, for example using digital filter algorithm and also statistical calibration methods. However software approaches were implemented for reducing chattering error, there has still generated chattering error due to external mechanical vibrations and magnetic field. The chattering errors can be reduced by changing leaf spring structure using mechanical hysteresis characteristics.

MHD and kinetic analysis of flow bursts in the Earth's plasma sheet

In an attempt to study the flow bursts in the Earth＇s plasma sheet we select an event that took place on August 7, 2004 in the expansion phase of a substorm, using data from the geomagnetic index, solar wind data, plasma and magnetic field observa- tions from C1 Cluster satellite （the Cluster mission has 4 satellites） and from Double Star TC-1 satellite. In MHD approach, TC-1 firstly observed the tailward flow, then the earthward, and finally the flow altemated in two directions. C1 firstly ob- served the earthward plasma flow, and then the tailward plasma flow. Before flow bursts are observed by TC-1 and C1, there are disturbances in local entropy with their tailward local entropy larger than those of the earthward. The kinetic features of the plasma flow observed by C1 are similar to those in MHD. However, kinetic characteristics of the plasma flow observed by TC-1 are far more than the description in MHD. The inadequacy mainly exists in two cases： （i） the firstly enhanced tailward flows given in MHD are found without significant increase of the energetic tailward flux; （ii） the almost stagnant flow in MHD is composed of the enhanced energetic ion flux in both earthward and tailward directions. The earthward flow burst observed by TC-1 might be multiple overshoots and rebounds. The earthward flow burst observed by C1 might be simply rebounded in the near-Earth. The pulsation observed by C1 is earlier than that observed by TC-1 with the former intensity less than that of the latter. After the energetic ion flux in the tailward direction is significantly enhanced, the power spectrum intensity of the ULF wave commences to increase obviously, which may suggest that the stream instability is closely correlated with ULF pulsations.

Study on Blade Surface Flow around Wind Turbine by Using LDV Measurements

This paper has attempted to study a mechanism of three-dimensional flow around a horizontal axis wind turbine(HAWT) rotor blade. An experimental study of the flow phenomenon in the vicinity of the wind turbine blade is a challenging endeavor. In this research, the HAWT model with 2.4 m diameter was tested in the large wind tunnel. The flow around the rotating blade surface was measured simultaneously for three velocity components, and two probes were used for the synchronized measurement of three-dimensional flow components. The local velocity was detected for the single seeding particle measured in the point where three pairs of laser beams intersected. Blade sections of interest in this study are composed of radial positions r/R = 0.3, 0.5 and 0.7. Optimum and low tip speed ratio flow characteristics were also compared. The velocity flow vector, skin friction coefficient and bound circulation were calculated from LDV measurements, and the experimental research showed reasonably and clearly the experimental results.

Non-axisymmetric Flow Characteristics in Centrifugal Compressor

The flow field distribution in centrifugal compressor is significantly affected by the non-axisymmetric geometry structure of the volute.The experimental and numerical simulation methods were adopted in this work to study the compressor flow field distribution with different flow conditions.The results show that the pressure distribution in volute is characterized by the circumferential non-uniform phenomenon and the pressure fluctuation on the high static pressure zone propagates reversely to upstream,which results in the non-axisymmetric flow inside the compressor.The non-uniform level of pressure distribution in large flow condition is higher than that in small flow condition,its effect on the upstream flow field is also stronger.Additionally,the non-uniform circumferential pressure distribution in volute brings the non-axisymmetric flow at impeller outlet.In different flow conditions,the circumferential variation of the absolute flow angle at impeller outlet is also different.Meanwhile,the non-axisymmetric flow characteristics in internal impeller can be also reflected by the distribution of the mass flow.The high static pressure region of the volute corresponds to the decrease of mass flow in upstream blade channel,while the low static pressure zone of the volute corresponds to the increase of the mass flow.In small flow condition,the mass flow difference in the blade channel is bigger than that in the large flow condition.

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.

A non-isothermal Couette slip gas flow

A steady plane subsonic compressible non-isothermal Couette gas flow is analyzed for moderately high and low Reynolds numbers.The flow channel is formed by two plates in relative motion.Two cases are considered:(a) isothermal walls where the temperatures of the plates are equal and constant and(b) with constant but different plate temperatures.The Knudsen number is Kn 0.1,which corresponds to the slip and continuum flow.The flow is defined by continuity,Navier-Stokes and energy continuum equations,along with the velocity slip and the temperature jump first order boundary conditions.An analytical solution for velocity and temperature is obtained by developing a perturbation scheme.The first approximation corresponds to the continuum flow conditions,while the others represent the contribution of the rarefaction effect.In addition,a numerical solution of the problems is given to confirm the accuracy of the analytical results.The exact analytical solution,for constant viscosity and conductivity is found for the isothermal walls case as well.It is shown that it is entirely a substitution to the exact numerical solution for the isothermal walls case.

On the hyperbolicity of flows

Let X be a C1 vector field on a compact boundaryless Riemannian manifold M（dim M≥2）,and A a compact invariant set of X.Suppose that A has a hyperbolic splitting,i.e.,T∧M = Es Eu with Es uniformly contracting and Eu uniformly expanding.We prove that if,in addition,A is chain transitive,then the hyperbolic splitting is continuous,i.e.,A is a hyperbolic set.In general,when A is not necessarily chain transitive,the chain recurrent part is a hyperbolic set.Furthermore,we show that if the whole manifold M admits a hyperbolic splitting,then X has no singularity,and the flow is Anosov.

Capillary blood flow in patients with dysmenorrhea treated with acupuncture

OBJECTIVE: To observe capillary blood flow at acupoints during acupuncture treatment of primary dysmenorrhea and gain new insights into its analgesic mechanism. METHODS: Patients with primary dysmenorrhea were enrolled and randomly assigned to a treatment or control group. Subjects' symptoms were differentiated into variousTraditional Chinese Medicine(TCM) syndromes and treated for 10 sessions with puncturing acupuncture or self-pressing right-hand Hegu(LI 4), adding other acupoints based on syndrome. Laser speckle was used to compare the change in the vasomotor amplitude and perfusion of the capillaries in Hegu(LI 4) before and during the treatment. Each subject was required to finish the period pain symptoms observation form, verbal rating scales, numerical rating scale, pain rating index, face rating scale, Zung self-rating depression scale, Zung self-rating anxiety scale, and numerical rating scale before and after treatments. RESULTS: After 10 sessions, the symptom scores, pain index(PI), and visual analog scale(VAS) decreased significantly in treatment group. The volume of blood flow in Hegu(LI 4) declined slightly. No significant evidence supported that needling caused capillary contraction, but the capillary vasomotor amplitude at Hegu(LI 4) increased remarkably. CONCLUSION: Acupuncture can increase the capillary blood flow, thus promoting the flow of Qi and blood in terms of TCM theory, which facilitates pain relief.

Mathematical modeling of micropolar fluid flow through an overlapping arterial stenosis

In this study a mathematical model for two-dimensional pulsatile blood flow through overlapping constricted tapered vessels is presented. In order to establish resemblance to the in vivo conditions, an improved shape of the time-variant overlapping stenosis in the elastic tapered artery subject to pulsatile pressure gradient is considered. Because it contains a suspension of all erythrocytes, the flowing blood is represented by micropolar fluid. By applying a suitable coordinate transformation, tapered cosine-shaped artery turned into non-tapered rectangular and a rigid artery. The governing nonlinear partial differential equations under the imposed realistic boundary conditions are solved using the finite difference method. The effects of vessel tapering on flow characteristics consid- ering their dependencies with time are investigated. The results show that by increasing the taper angle the axial velocity and volumetric flow rate increase and the microrota- tional velocity and resistive impedance reduce. It has been shown that the results are in agreement with similar data from the literature.