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.

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.

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.

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.

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.

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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Motion-pressure coupled control and simulation of long-endurance capability for multicapsule stratospheric airships

The current study focuses on the motion-pressure coupled control for a multicapsule stratospheric airship and transforms the path-tracking and heading-hold control of airships into guidance tracking with a time-varying weighted sum of longitudinal and lateral velocities by the definition of compound speed.Herein,an improved nonlinear predictive control method is provided to reduce the control energy consumption by the rolling optimization of controller parameters based on finite time intervals,ensuring infinite-time path-tracking tasks.Simultaneously,combined with the proposed cyclic regulation process of safe pressure between internal and external capsules,this study can fully reflect the force-thermal coupled rule of airships under the actions of atmospheric environment and maneuvering force,while evaluating the long-endurance capability of airships under the conditions of safe superheating and overpressure.The effectiveness of the motionpressure coupled controller was verified through numerical simulations,which can overcome the influence of environmental wind and achieve a tracking effect for the desired cruise path and compound speed.The airspeed provided during the cyclic circadian time caused the maximum superheating of the helium controlled within 30C.The helium in the internal and external capsules achieved circadian regulation.The equivalent micropore diameter of the capsule of 5 mm can achieve 55 days of long-endurance flight.The controller satisfies the requirements of cruise-flight application modes for multicapsule stratospheric airships with important engineering value.

Plants Used as Antihypertensive

Hypertension is a critical health problem and worse other cardiovascular diseases.It is mainly of two types:Primary or essential hypertension and Secondary hypertension.Hypertension is the primary possibility feature for coronary heart disease,stroke and renal vascular disease.Herbal medicines have been used for millions of years for the management and treatment of hypertension with minimum side effects.Over aim to write this review is to collect information on the anti-hypertensive effects of natural herbs in animal studies and human involvement as well as to recapitulate the underlying mechanisms,from the bottom of cell culture and ex-vivo tissue data.According to WHO,natural herbs/shrubs are widely used in increasing order to treat almost all the ailments of the human body.Plants are the regular industrial units for the invention of chemical constituents,they used as immunity booster to enhance the natural capacity of the body to fight against different health prob-lems as well as herbal medicines and food products also.Eighty percent population of the world(around 5.6 billion people)consume medicines from natural plants for major health concerns.This review provides a bird’s eye analysis primarily on the traditional utilization,phytochemical constituents and pharmacological values of medicinal herbs used to normalize hypertension i.e.Hibiscus sabdariffa,Allium sativum,Andrographis paniculata,Apium graveolens,Bidenspilosa,Camel-lia sinensis,Coptis chinensis,Coriandrum sativum,Crataegus spp.,Crocus sativus,Cymbopogon citrates,Nigella sativa,Panax ginseng,Salviaemiltiorrhizae,Zingiber officinale,Tribulus terrestris,Rauwolfiaserpentina,Terminalia arjuna etc.

Liver cirrhosis and arterial hypertension

Characteristic findings in patients with cirrhosis are vasodilatation with low overall systemic vascular resistance, high arterial compliance, increased cardiac output, secondary activation of counter-regulatory systems （renin-angiotensin-aldosterone system, sympathetic nervous system, release of vasopressin）, and resistance to vasopressors. The vasodilatory state is mediated through adrenomedullin, calcitonin generelated peptide, nitric oxide, and other vasodilators, and is most pronounced in the splanchnic area. This constitutes an effective （although relative） counterbalance to increased arterial blood pressure. This review considers the alterations in systemic hemodynamics in patients with cirrhosis in relation to essential hypertension and arterial hypertension of the renal origin. Subjects with arterial hypertension （essential, secondary） may become normotensive during the development of cirrhosis, and arterial hypertension is rarely manifested in patients with cirrhosis, even in cases with renovascular disease and high circulating renin activity. There is much dispute as to the understanding of homoeostatic regulation in cirrhotic patients with manifest arterial hypertension. This most likely includes the combination of vasodilatation and vasoconstriction in parallel.

＂One-for-several＂ rotor VVVF Technique apply to water injection station

In the process of oilfield water injection volume of injection allocation often appear with the pump displacement situation does not match, the widespread adoption of stator frequency technology allows the pump displacement and volume of injection allocation phase matching. But the technology in pump class load application speed range is limited, there is still a reflux valve control blind area,＂ turn off undead＂ problem. ＂ One-for-several＂ rotor frequency Technique in water injection station application, solved the control blind area problem, the full realization of the variable frequency close return voltage injection, at the same time, the successful implementation of the slip power efficient feedback. Stable water injection pressure of the system, and the electric energy is saved, satisfy the oilfield high efficiency, fine water needs, has a high application value.

Preparation of panda-shaped photonic crystal fibers with and without silver wire

A method of preparing panda-shaped photonic crystal fibers(PCFs)based on secondary drawing technology is proposed in this paper.The secondary drawing can not only reduce fiber diameter but also reduce core size by adding a glass sleeve.Silver-filled and non-silver-filled panda PCFs are prepared.The two ends of silver-filled panda PCF are connected with a broadband light source and a spectrometer,respectively,and the surface plasmon resonance phenomenon is detected.The secondary drawing technology provides a meaningful reference for the preparation of PCF in the future,and the prepared silver-filled panda PCF can be prepared into an optical fiber filter.

Research on Online Safety Precaution Technology of a High-medium Pressure Gas Regulator

In view of some of the characteristics of a high-medium pressure gas regulator, such as small fault samples, many fault types and complex fault features etc, in order to improve the accuracy of fault precaution in this paper, a fault diagnosis method based on the combination of the improved wavelet packet and pressure harmonic distortion rate is proposed. On the basis of the harmonic distortion rate of the outlet pressure and the energy value of each frequency band obtained by improved wavelet packet decomposition, the rules for fault data were summarized. Finally, a safety precaution model of the high-medium pressure gas regulator is established.

High dietary lipid level promotes low salinity adaptation in the marine euryhaline crab(Scylla paramamosain)

The physiological processes involved in adaptation to osmotic pressure in euryhaline crustaceans are highly energy demanding,but the effects of dietary lipids(fat)on low salinity adaptations have not been well evaluated.In the present study,a total of 120 mud crabs(Scylla paramamosain,BW=17.87±1.49 g)were fed control and high-fat(HF)diets,at both medium salinity(23‰)and low salinity(4‰)for 6 wk,and each treatment had 3 replicates with each replicate containing 10 crabs.The results indicated that a HF diet significantly mitigated the reduction in survival rate,percent weight gain and feed efficiency induced by low salinity(P<0.05).Low salinity lowered lipogenesis and activated lipolysis resulting in lipid depletion in the hepatopancreas of mud crabs(P<0.05).Thus,HF diets enhanced the process of lipolysis to supply more energy.In the gills,low salinity and the HF diet increased the levels of mitochondrial biogenesis markers,the activity of mitochondrial complexes,and the expression levels of genes related to energy metabolism(P<0.05).Consequently,the positive effects of the HF diet on energy metabolism in mud crabs at low salinity promoted osmotic pressure regulation.Specifically,significantly higher haemolymph osmotic pressure and inorganic ion content,as well as higher osmotic pressure regulatory enzyme activity in gills,and gene and protein expression levels of NaK-ATPase were observed in crabs fed the HF diet at low salinity(P<0.05).In summary,high dietary lipid levels improved energy provision to facilitate mitochondrial biogenesis,which increased ATP provision for osmotic pressure regulation of mud crabs.This study also illustrates the importance of dietary lipid nutrition supplementation for low salinity adaptations in mud crabs.

Regulatory control of the Na-Cl co-transporter NCC and its therapeutic potential for hypertension

Hypertension is the largest risk factor for cardiovascular disease,the leading cause of mortality worldwide.As blood pressure regulation is influenced by multiple physiological systems,hypertension cannot be attributed to a single identifiable etiology.Three decades of research into Mendelian forms of hypertension implicated alterations in the renal tubular sodium handling,particularly the distal convoluted tubule(DCT)-native,thiazide-sensitive Na-Cl cotransporter(NCC).Altered functions of the NCC have shown to have profound effects on blood pressure regulation as illustrated by the over activation and inactivation of the NCC in Gordon’s and Gitelman syndromes respectively.Substantial progress has uncovered multiple factors that affect the expression and activity of the NCC.In particular,NCC activity is controlled by phosphorylation/dephosphorylation,and NCC expression is facilitated by glycosylation and negatively regulated by ubiquitination.Studies have even found parvalbumin to be an unexpected regulator of the NCC.In recent years,there have been considerable advances in our understanding of NCC control mechanisms,particularly via the pathway containing the with-no-lysine[K](WNK)and its downstream target kinases,SPS/Ste20-related proline-alanine-rich kinase(SPAK)and oxidative stress responsive 1(OSR1),which has led to the discovery of novel inhibitory molecules.This review summarizes the currently reported regulatory mechanisms of the NCC and discusses their potential as therapeutic targets for treating hypertension.

Dynamic modeling and simulation of a pressurized system used in flight vehicle

For a typical pressurized system with a novel dual-stage gas pressure reducing regulator,a system model is established with modular models of various typical components. The simulation study on the whole working period shows that the general trends and magnitudes of simulation curves are in agreement with experimental measured curves. As the key component in the pressurized system, the regulator is studied by a series of numerical simulations to reveal the influences of various structure parameters on its stability. Furthermore, the variable ranges which can guarantee the stability of regulator and system are obtained to provide guidance for design. The modeling and analysis approach can be applied to other systems and components.