Search results for "Pressure control"

Self-blood pressure monitoring as a tool to increase hypertension awareness, adherence to antihypertensive therapy, and blood pressure control

2019

For many years, casual blood pressure (BP) taken by a sphygmomanometer in the clinic or at the physician's office has been used as the standard method for diagnosing hypertension. Even if such measurement has been the cornerstone on which our understanding of the consequences of hypertension is based, there is a huge and very consistent body of evidence indicating that casual measurements of BP may provide a very unreliable index for the evaluation of hypertension because of their variability. The two alternative ways of measuring BP that have been most commonly used are measurements made at home by the patient himself (home or self‐BP monitoring—SBPM) and measurements by ambulatory blood p…

A method for smoothly disengaging the load-holding valves of energy-efficient electro-hydraulic systems

2020

A novel self-contained, electro-hydraulic cylinder drive capable of passive load-holding, four-quadrant operations, and energy recovery was presented recently and implemented successfully. This solution improved greatly the energy efficiency and motion control in comparison to state-of-the-art, valve-controlled systems typically used in mobile or offshore applications. The passive load-holding function was realized by two pilot-operated check valves placed on the cylinder ports, where their pilot pressure is selected by a dedicated on/off electro valve. These valves can maintain the actuator position without consuming energy, as demonstrated on a single-boom crane. However, a reduced drop o…

Boom Motion Control Using Pressure Control Valve

2014

This paper focuses on the reduction in oscillations created by counterbalance valves by using a proportional pressure control valve. The motion control of a cylinder boom is presented using this valve, which is a 4/3-way directional control valve with the main spool in series with an upstream compensator. The input to the valve control is a main spool position reference and, indirectly, the compensator downstream pressure. This gives a different flow gain and, therefore, a different feedforward scheme as compared to applications with the more common pressure compensated flow control valve. The theory behind the pressure control valve is presented and applied to both a theoretical and experi…

Experimental and numerical analysis of a backpressure Banki inline turbine for pressure regulation and energy production

2020

Abstract Water distribution networks have become, in recent years, a major opportunity for the harvesting of renewable energy, which is otherwise dissipated though hydrovalves installed for discharge and pressure regulation. Mini and micro hydroturbines have the capability of providing the same functionality of hydrovalves, producing at the same time a relevant amount of electric power. In this paper a 10 kW prototype of a new compact in-line turbine, named Power Recovery System (PRS), has been designed, constructed and tested in the hydraulic laboratory of the University of Palermo. The proposed device is a Banki-type micro-turbine, with positive outflow pressure and a mobile regulating fl…

A New Device for Pressure Control and Energy Recovery in Water Distribution Networks

2017

The potential energy of the water in Water Distribution Networks (WDNs) usually exceeds the amount needed for delivery and consumption and, at the present time, it is mainly dissipated through Pressure Reducing Valves (PRVs) or Open Water Tanks. The present study suggests the use of a new energy-producing device, a Cross-flow turbine with positive outlet pressure named PRS (Power Recovery System), which can provide the same service as PRVs and water tanks, with additional significant hydropower production. After a short presentation of the PRS, the management rules of the proposed device are laid out, according to two possible modes. In the ‘passive’ mode, the piezometric level downstream o…

A new ifierarchical and intelligent control architecture based on distributed neural networks and expert systems applied to vehicle automation

2005

Adaptive control of a drilling system with unknown time-delay and disturbance

2016

In this paper, we address adaptive predictor feedback design for a simplified drilling system in the presence of disturbance and time-delay. The main objective is to stabilize the bottomhole pressure at a critical depth at a desired set-point directly. The stabilization of the dynamic system and the asymptotic tracking are demonstrated by the proposed adaptive control, where the adaptation employs Lyapunov update law design with normalization. The proposed method is evaluated using a high fidelity drilling simulator and cases from a North Sea drilling operation are simulated. The results show that the proposed predictor controller is effective to stabilize the bottom hole pressure within th…

The effects of telmisartan alone or with hydrochlorothiazide on morning and 24-h ambulatory BP control: results from a practice-based study (SURGE 2)

2012

Observational studies have shown that 24-h and morning ambulatory blood pressure (BP) control is low. This large-scale, practice-based study evaluated the effects of telmisartan 40 or 80 mg alone or in combination with hydrochlorothiazide (HCTZ) 12.5 mg on these BP parameters over 8 weeks; treatment was adjusted if clinic BP remained ≥140/90 mm Hg. A total of 863 patients were evaluated (baseline mean clinic BP, morning and 24-h ambulatory BP: 155±15/93±10 mm Hg, 137±15/83±11 mm Hg, 133±14/79±10 mm Hg, respectively; 68% were previously treated at baseline). Telmisartan with/without HCTZ significantly reduced the mean morning ambulatory BP (-8.2/-4.9 mm Hg), daytime ambulatory BP (-8.0/-4.7 …

Structural analysis of W3O/WO3 and TiO/TiO2 periodic multilayer thin films sputter deposited by the reactive gas pulsing process

2012

International audience; DC reactive sputtering was used to deposit titanium and tungsten-based metal/oxide periodic nanometric multilayers using pure metallic targets and Ar + O-2 gas mixture as reactive atmosphere. The innovative technique namely, the reactive gas pulsing process allows switching between the metal and oxide to prepare a periodic multilayered structure with various metalloid concentrations and nanometric dimensions. The same pulsing period was used for each deposition to produce metal-oxide periodic alternations close to 10 nm. Structure, crystallinity and chemical composition of these films were systematically investigated by Raman spectroscopy, X-ray diffraction and Energ…

Impeller optimization in crossflow hydraulic turbines

2021

Crossflow turbines represent a valuable choice for energy recovery in aqueducts, due to their constructive simplicity and good efficiency under variable head jump conditions. Several experimental and numerical studies concerning the optimal design of crossflow hydraulic turbines have already been proposed, but all of them assume that structural safety is fully compatible with the sought after geometry. We show first, with reference to a specific study case, that the geometry of the most efficient impeller would lead shortly, using blades with a traditional circular profile made with standard material, to their mechanical failure. A methodology for fully coupled fluid dynamic and mechanical …