In-situ pressure-preserved coring for deep exploration:Insight into the rotation behavior of the valve cover of a pressure controller

In-situ pressure-preserved coring(IPP-Coring)is considered to be the most reliable and efficient method for the identification of the scale of oil and gas resources.During IPP-Coring,because the rotation behavior of the pressure controller valve cover in different medium environments is unclear,interference between the valve cover and inner pipe may occur and negatively affect the IPP-Coring success rate.To address this issue,we conducted a series of indoor experiments employing a high-speed camera to gain greater insights into the valve cover rotation behavior in different medium environments,e.g.,air,water,and simulated drilling fluids.The results indicated that the variation in the valve cover rotation angle in the air and fluid environments can be described by a one-phase exponential decay function with a constant time parameter and by biphasic dose response function,respectively.The rotation behavior in the fluid environments exhibited distinct elastic and gravitational acceleration zones.In the fluid environments,the density clearly impacted the valve cover closing time and rotation behavior,whereas the effect of viscosity was very slight.This can be attributed to the negligible influence of the fluid viscosity on the drag coefficient found in this study;meanwhile,the density can increase the buoyancy and the time period during which the valve cover experienced a high drag coefficient.Considering these results,control schemes for the valve cover rotation behavior during IPP-Coring were proposed for different layers and geological conditions in which the different drilling fluids should be used,e.g.,the use of a high-density valve cover in high-pore pressure layers.

Mathematical model and magnetic-control mechanism of the stability of rotating spray transfer

To realize stable rotating spray transfer in the region of high constant current is the key of realizing high deposition rate MAG welding process without helium in shielding gas and extending the welding current range of traditional MAG welding process. In this paper, the magnetic control mechanism of the rotating spray transfer is stated and mathematical model is given. Theoretic basis is established, which implements high deposition rate MAG welding process with magnetic control instead of helium in shielding gas.

Control of seismic and operational vibrations of rotating machines using semi-active mounts

A dual isolation problem for rotating machines consists of isolation of housing structures from the machine vibrations and protection of machines during an earthquake to maintain their functionality. Desirable characteristics of machine mounts for the above two purposes can differ significantly due to difference in nature of the excitation and performance criteria in the two situations. In this paper, relevant response quantities are identified that may be used to quantify performance and simplified models of rotating machines are presented using which these relevant response quantities may be calculated. Using random vibration approach with a stationary excitation, it is shown that significant improvement in seismic performance is achievable by proper mount design. Results of shaking table experiments performed with a realistic setup using a centrifugal pump are presented. It is concluded that a solution to this dual isolation problem lies in a semi-active mount capable switching its properties from ‘operation-optimum’ to ‘seismic-optimum’ at the onset of a seismic event.

SIMULATION OF ACTIVE CONTROL OF ROTATING STALL IN AXIAL COMPRESSOR

A theoretical system has been developed to simulate the control of rotating stall. Circulating disturbance was appended to the system to suppress the developing of rotating wave. The control system has slight influence on the systems critical B coefficient B cr . Self adaptive sector has been inserted into the proportion feed back control system to fit the nonlinear compressor system.

INTELLIGENT INTEGRATION CONTROL OF ROTATING DISK VIBRATION

The rotating disk is a basic machine part that is u sed widely in industry. The motion equation is transformed into the dynamic equa tion in real modal space. The personating intelligent integration is introduced to improve the existing control method. These modes that affect the transverse vibration mainly are included to simulate the vibration of rotating disk, and two methods are applied separately on condition that the sensor and the ac tuator are collocated and non collocated. The results obtained by all sided si mulations show that the new method can obtain better control effect, especially when the sensor and the actuator are non collocated.

Distributed stereoscopic rotating formation control of networks of second-order agents

Distributed stereoscopic rotating formation control of networks of second-order agents is investigated. A distributed control protocol is proposed to enable all agents to form a stereoscopic formation and surround a common axis. Due to the existence of the rotating mode, the desired relative position between every two agents is time-varying, and a Lyapunov-based approach is employed to solve the rotating formation control problem. Finally, simulation results are provided to illustrate the effectiveness of the theoretical results.

Controllable and high-throughput preparation of microdroplet using an ultra-high speed rotating packed bed

Microdroplets and their dispersion,with a large specific surface area and a short diffusion distance,have been applied in various unit operations and reaction processes.However,it is still a challenge to control the size and size distribution of microdroplets,especially for high-throughput generation.In this work,a novel ultra-high speed rotating packed bed(UHS-RPB)was invented,in which rotating foam packing with a speed of 4000-12000 r·min^(-1) provides microfluidic channels to disperse liquid into microdroplets with high throughput.Then generated microdroplets can be directly dispersed into a continuous falling film for obtaining a mixture of microdroplet dispersion.In this UHS-RPB,the effects of rotational speed,liquid initial velocity,liquid viscosity,liquid surface tension and packing pore size on the average size(d_(32))and size distribution of microdroplets were systematically investigated.Results showed that the UHS-RPB could produce microdroplets with a d_(32) of 25-63μm at a liquid flow rate of 1025 L·h^(-1),and the size distribution of the microdroplets accords well with Rosin-Rammler distribution model.In addi-tion,a correlation was established for the prediction of d_(32),and the predicted d_(32) was in good agreement with the experimental data with a deviation within±15%.These results demonstrated that UHS-RPB could be a promising candidate for controllable preparation of uniform microdroplets.

Active Vibration Control of Rotating Machines with Active Machine Foot Mounts on Soft Foundations Based on a 3D-Model

The paper presents a simplified 3D-model for active vibration control of rotating machines with active machine foot mounts on soft foundations, considering static and moment unbalance. After the model is mathematical described in the time domain, it is transferred into the Fourier domain, where the frequencies response functions regarding bearing housing vibrations, foundation vibrations and actuator forces are derived. Afterwards, the mathematical coherences are described in the Laplace domain and a worst case procedure is presented to analyze the vibration stability. For special controller structures in combination with certain feedback strategies, a calculation method is shown, where the controller parameters can be directly implemented into the stiffness matrix, damping matrix and mass matrix. Additionally a numerical example is presented, where the vibration stability and the frequency response functions are analyzed.

Method of ballistic control and projectile rotation in a novel railgun

In order to realize the ballistic control of the railgun and the flight stability of the projectile, a new type of railgun is designed, which can control the muzzle velocity and rotation rate. The method of the muzzle velocity and overload control is to adjust the voltage or other parameters of pulse power supply. It would be easy to change velocity accurately in large wide. Another widespread concern problem is launching the spinning stability projectile by railgun. This paper designed a new structure of additional rails to generate an unsymmetrical magnetic field to produce rotational torque in armature. The structure is simple and can control the rotation rate by linear changing the barrel parameters. The calculation formulas of interior ballistic are derived by Biot-Safar law. The important parameter is the deflection angle of the additional rails relative to the symmetry plane of main rail. The larger the angle, the greater the rotation torque generated in the armature. To maintain the flight stability of the projectile, the barrel structural parameters should be proportional to the projectile structural parameters. When changing the muzzle velocity, the rotation rate will also be the equal proportion change. So that the gyro stability is the same. The experiment proves that the railgun designed in this paper can launch the projectile to rotate. And the rotational projectile may not cause the transition or much arcs. This method expands the application of the railgun.

Rotational Friction Damper’s Performance for Controlling Seismic Response of High Speed Railway Bridge-Track System

CRTS-II slab ballastless track on bridge is a unique system in China high speed railway.The application of longitudinal continuous track system has obviously changed dynamic characteristics of bridge structure.The bridge system and CRTS-II track system form a complex nonlinear system.To investigate the seismic response of high speed railway(HSR)simply supported bridge-track system,nonlinear models of three-span simply supported bridge with piers of different height and CRTS-II slab ballastless track system are established.By seismic analysis,it is found that shear alveolar in CRTS-II track system is more prone to be damaged than bridge components,such as piers,girders and bearings.The result shows that the inconsistent displacement of bridge girders is the main cause of the CRTS-II track system’s damage.Then the rotational friction damper(RFD)is adopted,which utilizes the device’s rotation and friction to dissipate seismic energy.The hysteretic behavior of RFD is studied by numerical and experimental methods.Results prove that RFD can provide good hysteretic energy dissipation ability with stable performance.Furthermore,the analysis of RFD’s influence on seismic response of HSR bridge-track system shows that RFD with larger sliding force is more effective in controlling excessive inconsistent displacement where RFD is installed,though response of other bridge spans could slightly deteriorated.

Chaos and chaotic control in a relative rotation nonlinear dynamical system under parametric excitation

This paper studies the chaotic behaviours of a relative rotation nonlinear dynamical system under parametric excitation and its control. The dynamical equation of relative rotation nonlinear dynamical system under parametric excitation is deduced by using the dissipation Lagrange equation. The. criterion of existence of chaos under parametric excitation is given by using the Melnikov theory. The chaotic behaviours are detected by numerical simulations including bifurcation diagrams, Poincare map and maximal Lyapunov exponent. Furthermore, it implements chaotic control using nomfeedback method. It obtains the parameter condition of chaotic control by the Melnikov theory. Numerical simulation results show the consistence with the theoretical analysis. The chaotic motions can be controlled to periodmotions by adding an excitation term.

Mei Symmetries and Lie Symmetries for Nonholonomic Controllable Mechanical Systems with Relativistic Rotational Variable Mass

The Mei symmetries and the Lie symmetries for nonholonomic controllable mechanical systems with relativistic rotational variable mass are studied. The differential equations of motion of the systems are established. The definition and criterion of the Mei symmetries and the Lie symmetries of the system are studied respectively. The necessary and sufficient condition under which the Mei symmetry is Lie symmetry is given. The condition under which the Mei symmetries can be led to a new kind of conserved quantity and the form of the conserved quantity are obtained. An example is given to illustrate the application of the results.

The Precise Methods for the Measurement of Collimator Hole Angulation and Center of Rotation of SPECT by Adaptive Quality Control Phantom

The Adaptive Quality Control Phantom (AQCP) is a computer-controlled phantom which positions and moves a radioactive source in the Field of View (FOV) of an imaging nuclear medicine device on a definite path to produce a spatial distribution of gamma rays to perform QC Tests such as the Collimator Hole Angulation (CHA) and the Center of Rotation (COR) of Single Photon Emission Computer Tomography (SPECT). The collimator hole angulation for six collimators was measured using a point source and a computer-controlled cylindrical positioning system. In this method, the displacement of the image of a point source was examined as the AQCP was moving point source vertically away from the collimator face. The results of the high-accuracy measurement method of CHA show that the measurement accuracy for absolute angulation errors is better than ±0.024°. The Root Mean Square (RMS) of CHA for LEHR, LEHS and LEUHR collimators of SMV dual heads camera and LEGP, MEGP and HEGP of GE Millennium MG were evaluated to be 0.290°, 0.292°, 0.208°, 0.154°, 0.220° and 0.202°, respectively. It is to be added in this connection that the evaluated RMS of CHA for LEHR collimator with the distance variation from the collimator’s surface ±1 mm has been varied ±0.04 degree. A new method for the center of rotation assessment by AQCP is introduced and the results of this proposed method as compared with the routine QC test and their differences are discussed in detail. We defined and measured a new parameter called Dynamic Mechanical Error (DME) for applying the gantry motion correction.

Research and Simulation of Navigation Control System for Agricultural Unmanned Rotation Rotorcraft

In order to improve the efficiency of field operations, such as pesticide spraying and pest control, the development of new agricultural machinery has become the main goal of agricultural modernization. At present, small unmanned aerial vehicles(UAVs) have achieved good results in small area pesticide spraying, but they still do not meet the requirements of the big field operations. The rotation rotorcraft has the characteristics of low speed, good safety, super stol, strong endurance, strong wind resistance and simple mechanism, so it is very suitable for farmland operation. But at present, there are relatively few researches on the unmanned rotation rotorcraft at domestic and abroad, and there is no mature control theory system of unmanned rotation rotorcraft. Therefore, in order to solve the problem of navigation control system of unmanned rotation rotorcraft, the navigation control strategy of the rotation rotorcraft was studied in this paper, and the flight control strategy of the rotation rotorcraft was divided into two parts, the linear control and the turn control. The lateral correction strategy was used to control the rotorcraft, so as to complete the track guidance of the rotation rotorcraft. Using the matrix laboratory(MATLAB) modeling to simulate the circular trajectory and the serpentine trajectory, the maximum deviation of circular path offset was 1.1 m. The variance between the path angle and the given path angle was 6°. The maximum deviation of serpentine path offset was 0.6 m. The variance between the path angle and the given path angle was 8°. The simulation results showed that the rotorcraft could accomplish the scheduled trajectory task based on this control strategy.

Soft initial-rotation and H_∞ robust constant rotational speed control for rotational MEMS gyro

A novel soft initiai-rotation control system and an H∞ robust constant rotational speed controller （RCRSC） for a rotational MEMS （micro-electro-mechanical system） gyro are presented. The soft initial-rotation control system can prevent the possible tumbling down of the suspended rotor and ensure a smooth and fast initial-rotation process. After the initial-rotation process, in order to maintain the rotational speed accurately constant, the RCRSC is acquired through the mixed sensitivity design approach. Simulation results show that the actuation voltage disturbances from the internal carrier waves in the gyro is reduced by more than 15.3 dB, and the speed fluctuations due to typical external vibrations ranging from 10 Hz to 200 Hz can also be restricted to 10^-3 rad/s order.

Angular control of multi-mode resonance frequencies in obliquely deposited CoZr thin films with rotatable stripe domains

We investigate the angular-dependent multi-mode resonance frequencies in CoZr magnetic thin films with a rotatable stripe domain structure.A variable range of multi-mode resonance frequencies from 1.86 GHz to 4.80 GHz is achieved by pre-magnetizing the CoZr films along different azimuth directions,which can be ascribed to the competition between the uniaxial anisotropy caused by the oblique deposition and the rotatable anisotropy induced by the rotatable stripe domain.Furthermore,the regulating range of resonance frequency for the CoZr film can be adjusted by changing the oblique deposition angle.Our results might be beneficial for the applications of magnetic thin films in microwave devices.

The Electric-Field Controllable Non-Volatile 35° Rotation of Magnetic Easy Axis in Magnetoelectric CoFeB/(001)-Cut Pb(Mg_(1/3)Nb_(2/3))O_3-25%PbTiO_3 Heterostructure

Using in situ electric-field-modulated anisotropic magnetoresistance measurement, a large reversible and non- volatile in-plane rotation of magnetic easy axis of -35° between the positive and negative electrical poling states is demonstrated in C040Fe40B20//（001）-cut Pb（Mgl/3Nb2/3）O3-25PbTiO3 （PMN-PT）. The specific magneto- electric coupling mechanism therein is experimentally verified to be related to the synchronous in-plane strain rotation induced by 109° ferroelastic domain switching in the （001）-cut PMN-PT substrate.

Research of Strapdown Integrated Navigation System Based on Rota­tion Control Technology

To realize high-precision Single-axial Rotating FOG-SINS,a low-power,low-cost,middle-precision rotating control mechanism design for single-axial rotating navigation system is put forward.Through theory analysis,design and experimental verification,the rotating control mechanism has good control precision and high reliability,which meets the demands for developing middle&high-precision FOG-SINS.

稻麦轮作高标准农田控制排水对排水与氮素输出削减效果模拟

稻麦轮作区高标准农田建设中,通过加深排水沟提高麦作期农田排水降渍能力的同时,加大稻作期农田排水输出,不仅降低了水资源利用效率,而且加重了接纳水体的污染。本文基于江苏省扬州市沿运灌区稻麦轮作农田排水水文水质过程的监测结果,利用田间水文模型(DRAINMOD)模拟了长序列气象条件下,灌区提高农田降渍能力对稻田排水、氮素流失及灌溉需求的负面影响以及控制排水措施的积极效果。结果表明,在节水灌溉模式下,研究区排水沟深度由现状的60 cm加深至120 cm,排水间距由120 m加密至20 m时,稻作期排水量与总氮(TN)输出负荷增加9.0%~22.2%、氨氮(NH_(3)-N)输出负荷增加4.0%~16.8%、灌溉用水量增加9.6%~23.4%。若结合田间管理要求,实施控制排水则可有效缓解提高农田降渍能力造成的负面影响;当排水沟深为120 cm,间距为120~20 m时,稻作期控制排水可使排水量和TN输出负荷减少19.3%~35.3%、NH_(3)-N输出负荷减少7.6%~27.2%、灌溉用水量减少22.9%~40.0%。由于控制排水降低了地下排水梯度,相较于传统排水,农沟从60 cm加深至120 cm时,地下排水平均占比降至50.7%,灌溉用水量相应减少。综上,稻麦轮作农田控制排水具有显著的节水减排作用,可有效降低高标准农田建设中提高降渍能力所产生的负面影响。研究成果可为稻麦轮作区高标准农田建设与水环境保护提供理论依据与技术支撑。

我国设施生态农业主要模式及配套技术的研究与实践

设施生态农业是指在设施种植和设施养殖中采用清洁、绿色、健康生产方式,以提高资源利用效率、农产品产量与质量、环境效益为目标的生态农业模式。2002年农业部重点推广的设施生态农业模式主要有两大类:一类是种养沼三结合的“四位一体”生态模式,从最初以农户为单位的单体日光温室到以村庄为单位的种养结合生态温室群模式,拓展到在一个大区域内将大型猪场的粪污进行工业化沼气并网发电,沼液通过管道输送到农田来减少化肥施用和改良土壤的宏观生态农业模式,相关的结构配置、配套的种养殖技术和装备也在不断研发和提升中。另一类是采用综合性生态农业技术的设施生态农业模式,包括:采用各类立体/垂直栽培技术提高土地资源利用率;通过各种轮作栽培技术减少设施蔬菜土壤连作障碍和降低农药使用量;采用土壤健康栽培技术,通过有机肥的合理施用改善土壤性状;采用有机基质栽培技术,用农林废弃物发酵后的物料作为栽培基质为作物提供养分;采用覆盖防虫网、色板诱杀、灯光诱杀、高温封棚、蒸气消毒、有色膜覆盖土壤、天敌昆虫生物防治等病虫草害生态防治技术来减少有害生物发生。期望通过相关配套装备技术的进一步研发提高设施生态农业的信息化、自动化水平,实现设施农业的可持续发展。