Pressure Regulation for Earth Pressure Balance Control on Shield Tunneling Machine by Using Adaptive Robust Control

Most current studies about shield tunneling machine focus on the construction safety and tunnel structure stability during the excavation. Behaviors of the machine itself are also studied, like some tracking control of the machine. Yet, few works concern about the hydraulic components, especially the pressure and flow rate regulation components. This research focuses on pressure control strategies by using proportional pressure relief valve, which is widely applied on typical shield tunneling machines. Modeling of a commercial pressure relief valve is done. The modeling centers on the main valve, because the dynamic performance is determined by the main valve. To validate such modeling, a frequency-experiment result of the pressure relief valve, whose bandwidth is about 3 Hz, is presented as comparison. The modeling and the frequency experimental result show that it is reasonable to regard the pressure relief valve as a second-order system with two low corner frequencies. PID control, dead band compensation control and adaptive robust control（ARC） are proposed and simulation results are presented. For the ARC, implements by using first order approximation and second order approximation are presented. The simulation results show that the second order approximation implement with ARC can track 4 Hz sine signal very well, and the two ARC simulation errors are within 0.2 MPa. Finally, experiment results of dead band compensation control and adaptive robust control are given. The results show that dead band compensation had about 30° phase lag and about 20% off of the amplitude attenuation. ARC is tracking with little phase lag and almost no amplitude attenuation. In this research, ARC has been tested on a pressure relief valve. It is able to improve the valve＇s dynamic performances greatly, and it is capable of the pressure control of shield machine excavation.

Novel miniature pneumatic pressure regulator for hopping robots

A novel miniature pressure regulator is fabricated and studied. The regulator can easily be integrated into portable mechatronics or miniature robotic applications because of its lightweight and compact size. An especial poppet is designed to minimize its size and to withstand high-pressure. The pressure regulator is designed for a hopping robot which is powered by a combustion system. The hopping robot has great moving capacities such as jumping over big obstacles, wails and dit- ches. The regulator helps the hopping robot to decrease size and weight, and to sustain high pres- sure of oxygen and fuel tank. It will maintain constant output pressure to obtain suitable proportion of oxygen and fuel in the combustion cylinder. Dynamic simulation of the miniature pneumatic pres- sure regulator is performed. Experiments on prototype of miniature pneumatic pressure regulator are also carried out to validate the performance and satisfied performance is obtained.

Application of Single Neuron Adaptive PID Regulators with Auto-tuning Gain in Industrial Parameter(Pressure)Closed-loop Process Control Systems

A type of single neuron adaptive PID regulator with auto-tuning gain is proposed and applied to the work control of fans, waterpumps and air-pressers etc. in Handan Iron & Steel Compel China. The robusthess of induStrial parameter closed-loop process controlsystems is improved, and the work quality of the systems bettered.

Flow-rate Characteristics Measurement of Regulators Based on the Pressure Response in an Isothermal Tank

Regulators are important components in pneumatic system, and their flow-rate characteristics are the key parameters for designers. According to the correlatively international standard and national standard of China, which describe the flow-rate characteristics measurement method of pneumatic regulators, the pressure and the flow are measured point by point, and then the flow-rate characteristics curve is plotted point to point. This method has some disadvantages, such as equipment complexity, much air consumption, and low efficiency. To settle the problems presented above, this paper puts forward a new high efficient and energy saving flow-rate characteristics measurement method of regulators, which is based on the pressure response when charging and discharging to an isothermal tank without any flow meters. The measurement principle, the system and the steps are introduced. And the tracking differentiator is used for the data processing of the pressure difference. Two typical kinds of regulators were experimentally investigated, and their flow-rate characteristics curves were obtained with the new and the conventional method, respectively. Comparatively, it＇s proved that this new method is feasible because it is not only able to meet the demand of the measurement precision, but also to save energy and improve efficiency. Compared to the conventional method, the new method takes only about 1/10 amount of time and consumes about only 1/30 amount of air. Hopefully it will be able to serve as an international standard of flow-rate characteristics measurement method of regulators.

Pressure Regulating Pressure of A New Pressure Regulating Valve with Spring

A new type of pressure regulating valve for agriculture irrigation, which used spring to regulate pressure was studied. Through the spring regulating pres-sure test, it concluded that for the pressure regulating valve with same spring mod-el, the outer pressure became smal er than the inlet pressure of the system and with the changes of inlet pressure, the outlet pressure remained almost the same, and that when inlet pressure was constant, the valve with smal er spring diameter had lower outlet pressure, indicating that the pressure regulating effect of the spring was more obvious with smal er diameter.

Online control for pressure regulation of oxygen mask based on neural network

The aviation oxygen mask,which has a small volume of less than 1L and strong air tightness,imposes extremely high requirements on control performance of the oxygen regulator.Based on analyses of the operation principle of oxygen supply system,the dynamic model is established through the combination of mechanism analysis and experimental data.Considering that the traditional fixed-parameter controllers are difficult to meet the control requirements with changes in pulmonary ventilation,this paper presents an online feedback controller based on neural network compensation(NNC),with connection weights that can be updated without pre-training.Then mathematical simulations at different respiratory parameters,such as respiratory rate,are performed to verify the superior lower inspiratory resistance of controller with NNC.In terms of hardware,an embedded AI control platform is to complete the experimental verification.Furthermore,the work may have downward compatibility to achieve stable oxygen supply in civil fields,such as medical ventilators,high-altitude expeditions.

Study on a Novel Digital Electro－Hydraulic Pressure Valve with a Capillary Damping Tube Regulating Pressure

A digital electro-hydraulic 4-port differential pressure control valve with a novel principle and structure is presented. The valve is designed by applying the regulating pressure technique of a capillary damping tube and also making full use of double freedom of the spool motion. Thevalve can implement digitizing interface easily. The theoretical analysis and experimental resultsshow that the valve is not only very simple in structure and convenient in use, but also has manygood properties, such as fast response, no-null-shift, etc.

Research on the Pressure Regulator Effect on a Pneumatic Vibration Isolation System

The pneumatic vibration isolator(PVI)plays an increasingly important role in precision manufacturing.In this paper,aiming to detect the performance of the pressure regulator in the PVI system,a PVI testing system with a pressure regulator is designed and developed.Firstly,the structure of the pneumatic spring is presented and analyzed,and the nonlinear stiffness is obtained based on the ideal gas model and material mechanics.Then,according to the working principle and continuity equations of ideal airflow,a dynamic model of the PVI system with a pressure regulator is established.Through the simulation analysis,the vibration isolation performance is improved with the efficient and precise pressure regulator.The average values of both the vibration velocity and transmission rate decrease when the vibration is set to 4,10,20 and 40 Hz,respectively.The experiments demonstrate the reliability and effectiveness of the pressure regulator.This achievement will become an important basis for future research concerning precision manufacturing.

Practical application of pressure regulating technology for fire district in Meiyukou Coal Mine

Based on the simulated laboratory experiment of pressure balance for fire ex- tinguishing,the pressure regulating technology was summarized for the fire district in Meiyukou Coal Mine.The technology includes three measures for air pressure regulation, namely applying the pressure regulating chamber to balance the air pressure of fire district, increasing the air pressure of the working face,and filling the ground surface fractures.A good effect was obtained to prevent and extinguish the fire.When the measures fail to in- crease the pressure of working face or to regulate that of air chamber,the measure to fill the ground surface fractures will play an important role.

On the Methods of Digital Acupoint Pressure and Regulating Acupoint

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Assessment and regulation of ocean health based on ecosystem services: Case study in the Laizhou Bay, China

The ecosystem-based management of nearshore waters requires integrated assessment of ocean health and scientific guidance on artificial regulations to promote sustainable development. Quantitative approaches were developed in this paper to assess present and near-term ocean health based on ecosystem services. Results of the case study in the Laizhou Bay of China showed that the index score of ocean health was 0.785 6 out of 1.0 at present and was expected to range from 0.555 1 to 0.804 1 in the near-term future depending on different intensities of artificial regulation of negative pressures. Specifically, the results of ocean health at present mainly indicated that cultural services and provisioning services performed essentially perfectly while supporting services and regulating services functioned less well. It can be concluded that this nearshore ecosystem would partially lose supporting and regulating services in the near-term future if the increasing pressures were not wellregulated but that all of these categories of ecosystem services could be slightly improved if the negative pressures were fully controlled. Additionally, it is recommended that publicity and education on ecosystem services especially on cultural services and regulating services should be further strengthened. The analytical process and resulting quantification provide flexible tools to guide future development of regulations so as to facilitate ecosystem-based management in the coastal zone.

On the Blood Pressure in the Cardiovascular System

Background: Hemodynamics is a practical and complicated theoretical problem. The aim of this paper is to analyze the characteristics of blood pressure in the cardiovascular system changing with the mechanical parameters of blood vessels and the storage of some visceral organs. Method: The fluid network model was used for the study. The cardiovascular system was modeled as a system consisting of 20 segments of vessels. The main controlling parameters were determined first by using dimensional analysis. Then the responses of blood pressure of each segment of vessels were analyzed by changing the controlling parameters. Results: The parameters of the blood vessel of brain have the least influence on the pressures of other parts. The pressures of the system of blood vessels will decrease if some blood is stored in the liver or the abdominal vein system. Vice versa. The effects of regulation of blood on the variation of blood pressure are larger than the other controlling parameters. Conclusions: The controlling parameters of the abdominal aorta and ascending aorta affect greatly the blood pressure of each vessel.

典型控流调压阀后突扩体的压力特性

为了研究突扩体对控流调压阀门的增压减振作用,以典型控流调压阀门(活塞式调流阀和固定式锥形阀)为研究对象,采用物模试验和三维数值模拟相结合的研究方法,重点对2类阀门在不同突扩体型、阀门开度及空化强度下的阀后流态及管壁压力特性进行了观测分析,探究突扩比与阀后稳定压力的定量关系,试验阀门通径为150 mm,阀门直径为150~370 mm,突扩体长度为1000 mm.结果表明,突扩体能提升阀后管壁时均压力、减弱压力脉动的基本原理是水垫层效应.综合物模与数模试验结果,拟合得到了突扩比与阀后管壁稳定时均压力的关系式.突扩体可以提升阀门的工作背压,提升程度随突扩比的增大而渐缓.当突扩比为4.00时,阀后管壁稳定时均压力的增幅已非常平缓,趋于稳定.不同阀型试验结果差异小,说明突扩体的增压减振作用具有普适性.研究结果可供输水调压工程阀门段管道系统设计参考借鉴.

300 MW供热机组低压缸零出力热力性能、调峰性能和经济性能分析

供热机组低压缸零出力运行可有效提升机组供热能力和调峰深度。该文基于Ebsilon软件,建立300 MW供热机组抽凝工况和低压缸零出力工况的数学模型,从热力性能、调峰性能和经济性能三个维度对常规抽凝模式和低压缸零出力模式进行分析。结果表明,低压缸零出力模式能够有效增加机组的供热能力,并降低发电标准煤耗率,当主蒸汽量为957.6 t/h时,供热量比常规抽凝供热模式提高16.25%,发电标准煤耗率下降27.2 g/kWh。低压缸零出力模式下,虽然供热机组的电负荷不具备调节能力,但其最小电负荷低于常规抽凝供热模式,适宜参与电网的深度调峰。从净收益最大化的角度,当热负荷在162~310 MW时,应采用低压缸零出力模式进行供热;当热负荷在310~375 MW时,应采用抽凝模式进行供热。

高压氧舱恒湿平压系统的设计

目的:设计一种高压氧舱恒湿平压系统,以消除舱内静电火花造成的危害,保证氧舱的安全运行。方法:该系统的硬件主要由加湿装置、除湿装置、平压装置、主控制器、压力传感器、温湿度传感器等组成。其中,加湿装置主体为经过特殊加工后的防爆过滤瓶;除湿装置采用工业级风机过滤单元(fan filter unit,FFU),由蒸发器、冷凝器、风轮3个部分组成;平压装置主要由电磁阀和减压管路组成;主控制器选用EX3G-C系列PLC触摸屏一体机,温湿度传感器选用NWSF-1AT型号温湿度传感器,压力传感器选用TXYS-G1K2HN3型变送器。系统的软件控制程序采用指令表语言编程,通过PID(proportional-integral-derivative)控制算法实现整体控制。结果:经过测试,该系统可使高压氧舱内相对湿度恒定在70%,使舱内极难产生静电。结论:该系统能够调节氧舱内的湿度、减少静电火花产生,保证舱内治疗的安全。

分析师对环保信息的关注能提高重污染企业绿色投资吗?

以2012—2022年重污染上市企业为样本,利用文本分析探究分析师对环保信息的关注能否提高重污染企业绿色投资。研究发现,分析师对环保信息的关注能显著提高重污染企业绿色投资水平。机制检验表明,绿色信息披露质量和业绩压力发挥部分中介作用,环境规制发挥正向调节作用。异质性检验发现,分析师对环保信息的关注对国有企业和东部地区企业的促进作用更明显。研究结论为探索企业绿色投资的驱动因素提供了新视角,对推进环境污染防治和实现“双碳”目标具有一定的实践意义。

数字化转型赋能企业高质量发展:基于盈余压力的调节作用

针对数字化转型如何赋能企业高质量发展问题,以2012—2022年中国A股上市公司为研究样本,采用实证研究的方法,利用面板回归模型分析数字化转型对企业高质量发展的影响。研究表明:数字化转型与企业高质量发展正相关;盈余压力在数字化转型与企业高质量发展之间发挥正向调节作用;数字化转型对企业高质量发展的影响在国有企业和高新技术企业中更显著。研究结论为数字化转型赋能企业高质量发展提供参考。

地方政府债务、异质性环境规制与绿色技术创新——基于247个城市的面板数据分析

本文基于2011~2021年我国247个地级及以上城市的面板数据,实证检验了地方政府债务对绿色技术创新的影响,并探索了异质性环境规制在其中起到的中介效应。研究发现:(1)地方政府债务对绿色技术创新存在总体的促进作用;(2)从机制来看,地方政府债务通过削弱指导性环境规制、增强处罚性环境规制倒逼企业等主体促进绿色技术创新;(3)产业结构升级以及数字经济水平均对地方政府债务影响绿色技术创新存在正向的调节效应。

天然气调压橇故障分析处理

随着海外油田区块的开发,油田企业投资建设燃气轮机电站,将伴生气转化为油田生产所需的电能。由于规划中的天然气处理厂尚未建成,伴生气处理装置还不完善,伴生气含杂质多,经常出现天然气调压橇压力失调故障,直接影响燃气轮机安全运行。通过对两个不同厂商天然气调压橇的构成及调压阀工作原理的分析,分别提出采用油田伴生气调压橇的改造方案和厂商提供的指挥器装配错误修正方法,可保证燃气轮机在加速控制、一次调频、孤岛模式等工况下,天然气调压橇调整压力迅速、平稳,为海外油田区块原油产量上产稳产提供了技术支撑。

AGM隔板的装配压力对阀控式铅酸蓄电池性能的影响

研究了AGM隔板的注液量、注液种类、纤维直径、增强隔板以及初始压力等因素对装配压力的影响。实验证明,注液量为饱和吸液量的90%,装配压力控制在60 kPa左右,可以明显改善阀控式铅酸蓄电池的循环寿命。