Analysis and experimental study on resistance-increasing behavior of composite high efficiency autonomous inflow control device

Bottom water coning is the main reason to reduce the recovery of horizontal bottom water reservoir. By water coning, we mean the oil-water interface changes from a horizontal state to a mound-shaped cone and breaks through to the wellbore. Autonomous inflow control device(AICD) is an important instrument maintain normal production after bottom water coning, however, the resistance increasing ability of the swirl type AICD is insufficient at present, which seriously affects the water control effect. Aiming this problem, this paper designs a multi-stage resistance-increasing and composite type AICD. The separation mechanism of oil-water two phases in this structure, the resistance form of oil-water single phase and the resistance-increasing principle of water phase are analyzed. Establishing the dual-phase multi-stage separation and resistance-increasing model, and verified by measuring the throttling pressure drop and oil-water volume fraction of the AICD, it is found that the composite type AICD has the effect of ICD and AICD at the same time, which can balance the production rate of each well section at the initial stage of production, delay the occurrence of bottom water coning. In the middle and later stages of production, water-blocking can be effectively increased to achieve water control and stable production.After structural sensitivity analysis, the influence law of various structural parameters on the water control performance of composite AICD was obtained. The simulation calculation results show that,compared with the existing swirl type AICD, composite AICD has higher sensitivity to moisture content,the water phase throttling pressure drop is increased by 4.5 times on average. The composite AICD is suitable for the entire stage of horizontal well production.

Experimental Investigation on Vertical Hydraulic Transport of Ores in Deepsea Mining

Deepsea mining has been proposed since the 1960s to alleviate the lack of resources on land.Vertical hydraulic transport of collected ores from the seabed to the sea surface is considered the most promising method for industrial applications.In the present study,an indoor model test of the vertical hydraulic transport of particles was conducted.A noncontact optical method has been proposed to measure the local characteristics of the particles inside a vertical pipe,including the local concentration and particle velocity.The hydraulic gradient of ore transport was evaluated with various particle size distributions,particle densities,feeding concentrations and mixture flow velocities.During transport,the local concentration is larger than the feeding concentration,whereas the particle velocity is less than the mixture velocity.The qualitative effects of the local concentration and local fluid velocity on the particle velocity and slip velocity were investigated.The local fluid velocity contributes significantly to particle velocity and slip velocity,whereas the effect of the local concentration is marginal.A higher feeding concentration and mixture flow velocity result in an increased hydraulic gradient.The effect of the particle size gradation is slight,whereas the particle density plays a crucial role in the transport.

Theoretical and experimental investigations on an X-shaped vibration isolator with active controlled variable stiffness

A novel X-shaped variable stiffness vibration isolator(X-VSVI)is proposed.The Runge-Kutta method,harmonic balance method,and wavelet transform spectra are introduced to evaluate the performance of the X-VSVI under various excitations.The layer number,the installation angle of the X-shaped structure,the stiffness,and the active control parameters are systematically analyzed.In addition,a prototype of the X-VSVI is manufactured,and vibration tests are carried out.The results show that the proposed X-VSVI has a superior adaptability to that of a traditional X-shaped mechanism,and shows excellent vibration isolation performance in response to different amplitudes and forms of excitations.Moreover,the vibration isolation efficiency of the device can be improved by appropriate adjustment of parameters.

Multi-environment BSA-seq using large F3 populations is able to achieve reliable QTL mapping with high power and resolution: An experimental demonstration in rice

Bulked-segregant analysis by deep sequencing(BSA-seq) is a widely used method for mapping QTL(quantitative trait loci) due to its simplicity, speed, cost-effectiveness, and efficiency. However, the ability of BSA-seq to detect QTL is often limited by inappropriate experimental designs, as evidenced by numerous practical studies. Most BSA-seq studies have utilized small to medium-sized populations, with F2populations being the most common choice. Nevertheless, theoretical studies have shown that using a large population with an appropriate pool size can significantly enhance the power and resolution of QTL detection in BSA-seq, with F_(3)populations offering notable advantages over F2populations. To provide an experimental demonstration, we tested the power of BSA-seq to identify QTL controlling days from sowing to heading(DTH) in a 7200-plant rice F_(3)population in two environments, with a pool size of approximately 500. Each experiment identified 34 QTL, an order of magnitude greater than reported in most BSA-seq experiments, of which 23 were detected in both experiments, with 17 of these located near41 previously reported QTL and eight cloned genes known to control DTH in rice. These results indicate that QTL mapping by BSA-seq in large F_(3)populations and multi-environment experiments can achieve high power, resolution, and reliability.

Visualization and characterization of experimental hydraulic fractures interacting with karst fracture-cavity distributions

Karst fracture-cavity carbonate reservoirs,in which natural cavities are connected by natural fractures to form cavity clusters in many circumstances,have become significant fields of oil and gas exploration and exploitation.Proppant fracturing is considered as the best method for exploiting carbonate reservoirs;however,previous studies primarily focused on the effects of individual types of geological formations,such as natural fractures or cavities,on fracture propagation.In this study,true-triaxial physical simulation experiments were systematically performed under four types of stress difference conditions after the accurate prefabrication of four types of different fracture-cavity distributions in artificial samples.Subsequently,the interaction mechanism between the hydraulic fractures and fracture-cavity structures was systematically analyzed in combination with the stress distribution,cross-sectional morphology of the main propagation path,and three-dimensional visualization of the overall fracture network.It was found that the propagation of hydraulic fractures near the cavity was inhibited by the stress concentration surrounding the cavity.In contrast,a natural fracture with a smaller approach angle(0°and 30°)around the cavity can alleviate the stress concentration and significantly facilitate the connection with the cavity.In addition,the hydraulic fracture crossed the natural fracture at the 45°approach angle and bypassed the cavity under higher stress difference conditions.A new stimulation effectiveness evaluation index was established based on the stimulated reservoir area(SRA),tortuosity of the hydraulic fractures(T),and connectivity index(CI)of the cavities.These findings provide new insights into the fracturing design of carbonate reservoirs.

Experimental Study on the Electrochemical Performance of PEMFC under Different Assembly Forces

Proton exchange membrane fuel cell(PEMFC)is of paramount significance to the development of clean energy.The components of PEMFC are assembled using many pairs of nuts and bolts.The assembly champing bolt torque is critical to the electrochemical performance and mechanical stability of PEMFC.In this paper,a PEMFC with the threechannel serpentine flow field was used and studied.The different assembly clamping bolt torques were applied to the PEMFC in three uniform assembly bolt torque and six non-uniform assembly bolt torque conditions,respectively.And then,the electrochemical performance experiments were performed to study the effect of the assembly bolt torque on the electrochemical performance.The test results show that the assembly bolt torque significantly affected the electrochemical performance of the PEMFC.In uniform assembly bolt torque conditions,the maximal power density increased initially as the assembly bolt torque increased,and then decreased on further increasing the assembly torque.It existed the optimum assembly torque which was found to be 3.0 N·m in this work.In non-uniform assembly clamping bolt torque conditions,the optimum electrochemical performance appeared in the condition where the assembly torque of each bolt was closer to be 3.0 N·m.This could be due to the change of the contact resistance between the gas diffusion layer and bipolar plate and mass transport resistance for the hydrogen and oxygen towards the catalyst layers.This work could optimize the assembly force conditions and provide useful information for the practical PEMFC stack assembly.

Theoretical and experimental investigation of the resonance responses and chaotic dynamics of a bistable laminated composite shell in the dynamic snap-through mode

The dynamic model of a bistable laminated composite shell simply supported by four corners is further developed to investigate the resonance responses and chaotic behaviors.The existence of the 1:1 resonance relationship between two order vibration modes of the system is verified.The resonance response of this class of bistable structures in the dynamic snap-through mode is investigated,and the four-dimensional(4D)nonlinear modulation equations are derived based on the 1:1 internal resonance relationship by means of the multiple scales method.The Hopf bifurcation and instability interval of the amplitude frequency and force amplitude curves are analyzed.The discussion focuses on investigating the effects of key parameters,e.g.,excitation amplitude,damping coefficient,and detuning parameters,on the resonance responses.The numerical simulations show that the foundation excitation and the degree of coupling between the vibration modes exert a substantial effect on the chaotic dynamics of the system.Furthermore,the significant motions under particular excitation conditions are visualized by bifurcation diagrams,time histories,phase portraits,three-dimensional(3D)phase portraits,and Poincare maps.Finally,the vibration experiment is carried out to study the amplitude frequency responses and bifurcation characteristics for the bistable laminated composite shell,yielding results that are qualitatively consistent with the theoretical results.

Dynamic Modeling and Experimental Verification of an RPR Type Compliant Paralle Mechanism with Low Orders

Efficiency of calculating a dynamic response is an important point of the compliant mechanism for posture adjustment.Dynamic modeling with low orders of a 2R1T compliant parallel mechanism is studied in the paper.The mechanism with two out-of-plane rotational and one lifting degrees of freedom(DoFs)plays an important role in posture adjustment.Based on elastic beam theory,the stiffness matrix and mass matrix of the beam element are established where the moment of inertia is considered.To improve solving efficiency,a dynamic model with low orders of the mechanism is established based on a modified modal synthesis method.Firstly,each branch of the RPR type mechanism is divided into a substructure.Subsequently,a set of hypothetical modes of each substructure is obtained based on the C-B method.Finally,dynamic equation of the whole mechanism is established by the substructure assembly.A dynamic experiment is conducted to verify the dynamic characteristics of the compliant mechanism.

Analysis of the Erosion-Corrosion Mechanism of the Air Cooler in a Hydrocracking Unit:A Numerical and Experimental Study

Corrosion leakages often occur in the air cooler of a hydrocracking unit,with the failure sites mainly located in the entrance area of the tubes.An analysis of the macroscopic morphology and corrosion products confirmed that the damage was caused by erosion-corrosion(E-C).Numerical and experimental methods were applied to investigate the E-C mechanism in the air cooler.Computational fluid dynamics(CFD)was used to calculate the hydrodynamic parameters of the air cooler.The results showed that there was a biased flow in the air cooler,which led to a significant increase in velocity,turbulent kinetic energy and wall shear within 0.2 m of the tube entrance.A visualization experiment was then performed to determine the principles of migration and transformation of multiphase flow in the air cooler tubes.Various flow patterns(pure droplet flow,mist flow,and annular flow)and their evolutionary processes were clearly depicted experimentally.The initiation mechanism and processes leading to the development of E-C in the air cooler were also determined.This study provided a comprehensive explanation for the E-C failures that occur in air coolers during operation.

Experimental study on reactions between alkaline basaltic melt and orthopyroxenes: constraints on the evolution of lithospheric mantle in the North China Craton

The experimental results of the reactions between an alkaline basaltic melt and mantle orthopyroxenes under high-temperature and high-pressure conditions of 1300–1400℃ and 2.0–3.0 GPa using a six-anvil apparatus are reported in this paper.The reactions are proposed to simulate the interactions between melts from the asthenospheric mantle and the lithospheric mantle.The starting melt in the experiments was made from the alkaline basalt occurring in Fuxin,Liaoning Province,and the orthopyroxenes were separated from the mantle xenoliths in Damaping,Hebei Province.The results show that clinopyroxenes were formed in all the reactions between the alkaline basaltic melt and orthopyroxenes under the studied P–T conditions.The formation of clinopyroxene in the reaction zone is mainly controlled by dissolution–crystallization,and the chemical compositions of the reacted melt are primarily infl uenced by the diff usion eff ect.Temperature is the most important parameter controlling the reactions between the melt and orthopyroxenes,which has a direct impact on the melting of orthopyroxenes and the diff usion of chemical components in the melt.Temperature also directly controls the chemical compositions of the newly formed clinopyroxenes in the reaction zone and the reacted melt.The formation of clinopyroxenes from the reactions between the alkaline basaltic melt and orthopyroxenes can result in an increase of CaO and Al_(2)O_(3) contents in the rocks containing this mineral.Therefore,the reactions between the alkaline basaltic melt from the asthenospheric mantle and orthopyroxenes from the lithospheric mantle can lead to the evolution of lithospheric mantle in the North China Craton from refractory to fertile with relatively high CaO and Al 2 O 3 contents.In addition,the reacted melts in some runs were transformed from the starting alkaline basaltic into tholeiitic after reactions,indicating that tholeiitic magma could be generated from alkaline basaltic one via reactions between the latter and orthopyroxene.

Experimental Study of Liquid Metal Flow for the Development of a Contact-Less Control Technique

The article presents an experimental study on the flow of an eutectic gallium alloy in a cylindrical cell,which is placed in an alternating magnetic field.The magnetic field is generated by a coil connected to an alternating current source.The coil is located at a fixed height in such a way that its plane is perpendicular to the gravity vector,which in turn is parallel to the axis of the cylinder.The position of the cylinder can vary in height with respect to the coil.The forced flow of the considered electrically conductive liquid is generated due to the action of the localized electromagnetic force.It is assumed that under the action of the alternating magnetic field,the liquid is heated uniformly,and the resulting heat is quickly absorbed by the forced flow,so that liquid free convection can be neglected.The experiment is carried out using an ultrasonic Doppler anemometer.One transducer is installed in the axially located cylinder sluice and the other transducer is placed in the near-wall region.According to the results,a velocity profile,corresponding to a two-tori flow pattern can be hardly obtained in the low frequency range of the power supply.However,this is possible in the high frequency range.The average velocity profiles depend essentially on the location of the coil relative to the cell.The spectral analysis of velocity signals shows that the amplitude of the velocity pulsations is comparable to the average value of the flow velocity.Such experimental results and their verification through comparison with numerical calculations are intended to support the development of new methods for reducing the intensity of vortex flows during the electromagnetic separation of impurities through an electromagnetic induction mechanism(able to produce an electromotive force that displaces particles).

Experimental Investigation of Wave-Current Loads on a Bridge Shuttle-Shaped Cap–Pile Foundation

To scrutinize the characteristics of wave-current loads on a bridge shuttle-shaped cap–pile foundation,a 1:125 test model was considered in a laboratory flume.The inline,transverse and vertical wave–current forces acting on the shuttle-shaped cap-pile group model were measured considering both random waves and a combination of random waves with a current.The experimental results have shown that the wave-current forces can be well correlated with the wave height,the wavelength,the current velocity,the incident direction and the water level in the marine environment.An increase in the current velocity can lead to a sharp increase in the inline and transverse wave-current forces,while the vertical wave-current force decreases.Moreover,the wave-current forces are particularly strong when a combination of high tide,strong wave and strong current is considered.

Network pharmacology study and in vitro experimental validation of Xiaojianzhong decoction against gastric cancer

BACKGROUND Cancer is one of the most serious threats to human health worldwide.Conventional treatments such as surgery and chemotherapy are associated with some drawbacks.In recent years,traditional Chinese medicine treatment has been increasingly advocated by patients and attracted attention from clinicians,and has become an indispensable part of the comprehensive treatment for gastric cancer.AIM To investigate the mechanism of Xiaojianzhong decoction(XJZ)in the treatment of gastric cancer(GC)by utilizing network pharmacology and experimental validation,so as to provide a theoretical basis for later experimental research.METHODS We analyzed the mechanism and targets of XJZ in the treatment of GC through network pharmacology and bioinformatics.Subsequently,we verified the impact of XJZ treatment on the proliferative ability of GC cells through CCK-8,apoptosis,cell cycle,and clone formation assays.Additionally,we performed Western blot analysis and real-time quantitative PCR to assess the protein and mRNA expression of the core proteins.RESULTS XJZ mainly regulates IL6,PTGS2,CCL2,MMP9,MMP2,HMOX1,and other target genes and pathways in cancer to treat GC.The inhibition of cell viability,the increase of apoptosis,the blockage of the cell cycle at the G0/G1 phase,and the inhibition of the ability of cell clone formation were observed in AGS and HGC-27 cells after XJZ treatment.In addition,XJZ induced a decrease in the mRNA expression of IL6,PTGS2,MMP9,MMP2,and CCL2,and an increase in the mRNA expression of HOMX1.XJZ significantly inhibited the expression of IL6,PTGS2,MMP9,MMP2,and CCL2 proteins and promoted the expression of the heme oxygenase-1 protein.CONCLUSION XJZ exerts therapeutic effects against GC through multiple components,multiple targets,and multiple pathways.Our findings provide a new idea and scientific basis for further research on the molecular mechanisms underlying the therapeutic effects of XJZ in the treatment of GC.

Unexpected Diversity in Ecosystem Nutrient Responses to Experimental Drought in Temperate Grasslands

The responses of ecosystem nitrogen (N) and phosphorus (P) to drought are an important component of globalchange studies. However, previous studies were more often based on site-specific experiments, introducing a significantuncertainty to synthesis and site comparisons. We investigated the responses of vegetation and soil nutrientsto drought using a network experiment of temperate grasslands in Northern China. Drought treatment (66%reduction in growing season precipitation) was imposed by erecting rainout shelters, respectively, at the driest,intermediate, and wettest sites. We found that vegetation nutrient concentrations increased but soil nutrient concentrationsdecreased along the aridity gradient. Differential responses were observed under experimentaldrought among the three grassland sites. Specifically, the experimental drought did not change vegetation andsoil nutrient status at the driest site, while strongly reduced vegetation but increased soil nutrient concentrationsat the site with intermediate precipitation. On the contrary, experimental drought increased vegetation N concentrationsbut did not change vegetation P and soil nutrient concentrations at the wettest site. In general, the differentialeffects of drought on ecosystem nutrients were observed between manipulative and observationalexperiments as well as between sites. Our research findings suggest that conducting large-scale, consistent, andcontrolled network experiments is essential to accurately evaluate the effects of global climate change on terrestrialecosystem bio-geochemistry.

On the Unipolar Generator: An Experimental and Theoretical Study

When studying the phenomenon of the induced electromotive force, which originates from Faraday’s unipolar inductor, the contrast between Faraday’s view of the magnetic field dynamic lines and the theory of relativity is revealed. In order to remove this contradiction, this phenomenon was studied in depth, theoretically and experimentally, using an experimental setup similar to Faraday’s. Calculations of the induced electromotive force, based on relativity on the one hand and on Faraday’s view on the other were made with the help of measurements of the magnetic field components. Accurate magnetic field measurements are confirmed by analytical calculations. Precise-induced electromotive force measurements confirmed Faraday’s view and contradicted the theory of relativity.

Construction and Practice of First-Class Courses on Virtual Simulation Experimental Teaching of Urban Overpasses

Virtual simulation experiment,as a new way to promote the digital transformation of education,has a broad development prospect and application value.The civil engineering experimental volume and space are huge,it has a long construction period,is highly dangerous,and is difficult to experiment with.In order to solve the contradiction between the traditional theory teaching of civil engineering and the engineering training of students,the construction of virtual simulation experimental teaching courses with a high degree of realism,intuition,and accuracy can be used as a useful supplement and innovation of experimental and practical teaching.This paper takes the virtual simulation experimental teaching course of urban overpasses as an example,introduces the necessity and practicability of the course construction,and describes the experimental principle structure of the course,the simulation scene design,the experimental teaching process,the experimental method,etc.The course has achieved good application results,and it has been recognized as the first-class virtual simulation teaching course of the Chongqing Municipal Government,which provides certain references to the construction of the same type of courses in the civil engineering profession.

Exploration on Teaching Reform of Medical Functional Experimental Science for International Students

Medical Functional Experiment Science, a bridge between basic medicine and clinical medicine, integrates classical experimental teaching contents of three courses including physiology, pathophysiology and pharmacology. This course not only helps students to verify and reinforce theoretical knowledge, but also cultivates their capability of scientific thinking to discover and solve problems. Based on the characteristics of international students and current situation of the teaching platform in the laboratory at Yangtze University, this paper discusses a series of problems in the Medical Functional Experiment Science teaching for international students and puts forward some measures for teaching reform including optimizing experimental content, innovating experimental teaching methods and establishing effective experimental evaluation mode, in order to cultivate more international medical students with innovative ability.

Experimental investigation and flow analysis of clear-water scour around pier and abutment in proximity

Local scour around bridge piers and abutments is one of the most significant causes of bridge failure.Despite a plethora of studies on scour around individual bridge piers or abutments,few studies have focused on the joint impact of a pier and an abutment in proximity to one another on scour.This study conducted laboratory experiments and flow analyses to examine the interaction of piers and abutments and their effect on clear-water scour.The experiments were conducted in a rectangular laboratory flume.They included 18 main tests(with a combination of different types of piers and abutments)and five control tests(with individual piers or abutments).Three pier types(a rectangular pier with a rounded edge,a group of three cylindrical piers,and a single cylindrical pier)and two abutment types(a wingewall abutment and a semicircular abutment)were used.An acoustic Doppler velocimeter was used to measure the three-dimensional flow velocity for analyses of streamline,velocity magnitude,vertical velocity,and bed shear stress.The results showed that the velocity near the pier and abutment increased by up to 80%.The maximum scour depth around the abutment increased by up to 19%.In contrast,the maximum scour depth around the pier increased significantly by up to l71%.The presence of the pier in the vicinity of the abutment led to an increase in the scour hole volume by up to 87%relative to the case with a solitary abutment.Empirical equations were also derived to accurately estimate the maximum scour depth at the pier adjacent to the abutment.

Vertical impedance functions of pile groups under low-to-high loading amplitudes:numerical simulations and experimental validation

Piles in a group experience additional displacements in soil due to pile-to-pile interactions apart from those resulting from the external loading.The effect of these interactions determined assuming soil as an elastic and/or viscoelastic material on pile head impedance functions of the pile group is studied by relating the group stiffness to the static stiffness of a single pile.However,the prevailing elastic solutions may misestimate the resulting pile group response due to the lack of consideration for either soil(material)and/or soil-pile interface nonlinearities.It is well established that soil behaves nonlinearly under moderate-to-high loading amplitudes,and besides,the soil-pile interface nonlinearity can exist even at small loading amplitudes.This study addresses the effects of these nonlinearities on the vertical impedance functions of a 3×3-pile group using numerical methods by direct analyses and superposition using pile-to-pile interaction factors.The numerical results are validated using scaled model tests under 1 g conditions.The results highlight the overestimation of pile-to-pile interactions in the pile group when assuming elastic soil conditions.The cases either by direct analyses or superposition approach involving soil and soil-pile interface nonlinearities agree well with the experimental pile group responses under close-to-elastic and nonlinear conditions.

Blast wave characteristics of multi-layer composite charge:Theoretical analysis,numerical simulation,and experimental validation

This article investigates the characteristics of shock wave overpressure generated by multi-layer composite charge under different detonation modes.Combining dimensional analysis and the explosion mechanism of the charge,a peak overpressure prediction model for the composite charge under singlepoint detonation and simultaneous detonation was established.The effects of the charge structure and initiation method on the overpressure field characteristics were investigated in AUTODYN simulation.The accuracy of the prediction model and the reliability of the numerical simulation method were subsequently verified in a series of static explosion experiments.The results reveal that the mass of the inner charge was the key factor determining the peak overpressure of the composite charge under single-point detonation.The peak overpressure in the radial direction improved apparently with an increase in the aspect ratio of the charge.The overpressure curves in the axial direction exhibited a multi-peak phenomenon,and the secondary peak overpressure even exceeded the primary peak at distances of 30D and 40D(where D is the charge diameter).The difference in peak overpressure among azimuth angles of 0-90°gradually decreased with an increase in the propagation distance of the shock wave.The coupled effect of the detonation energy of the inner and outer charge under simultaneous detonation improved the overpressure in both radial and axial directions.The difference in peak overpressure obtained from model prediction and experimental measurements was less than 16.4%.