Search results for "Pressure control"
showing 10 items of 26 documents
Lung density distribution in dynamic CT correlates with oxygenation during pressure-controlled ventilation of pigs with lavage-ARDS
2000
Long-term volume-targeted pressure-controlled ventilation: sense or nonsense?
2017
The technology underlying the development of novel ventilatory modes for long-term noninvasive ventilation of patients with chronic hypercapnia is continuously evolving. Volume-targeted pressure-controlled ventilation is a hybrid ventilation mode designed to combine the advantages of conventional ventilation modes, while avoiding their drawbacks. However, manufacturers have created different names and have patented algorithms and set-up variables, which can result in confusion for physicians and respiratory therapists. In addition, clear evidence for the superiority of this novel mode has not yet been established. These factors have most likely hindered more widespread use of this mode in c…
A new ifierarchical and intelligent control architecture based on distributed neural networks and expert systems applied to vehicle automation
2005
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…
Coupled Electric and Hydraulic Control of a PRS Turbine in a Real Transport Water Network
2019
Although many devices have recently been proposed for pressure regulation and energy harvesting in water distribution and transport networks, very few applications are still documented in the scientific literature. A new in-line Banki turbine with positive outflow pressure and a mobile regulating flap, named Power Recovery System (PRS), was installed and tested in a real water transport network for the regulation of pressure and flow rate. The PRS turbine was directly connected to a 55 kW asynchronous generator with variable rotational velocity, and coupled to an inverter. The start-up tests showed how automatic adjustment of the flap position and the runner velocity variation are able to c…
Physician attitudes to blood pressure control
2011
OBJECTIVES: The Supporting Hypertension Awareness and Research Europe-wide (SHARE) physician survey aimed to qualify the key challenges that physicians face when trying to get patients to blood pressure (BP) goal. METHODS: The SHARE survey was open to physicians involved in the treatment of patients with hypertension, was anonymous, and was designed to take 15 min to complete. The survey included 45 questions covering physicians' demographic information, views on the BP targets recommended by the European Society of Hypertension-European Society of Cardiology guidelines, opinions on acceptable levels of BP control, and perceptions about the challenges associated with getting patients to BP …
The effects of telmisartan alone or in combination with hydrochlorothiazide on morning home blood pressure control: The SURGE 2 practice-based study
2013
SURGE 2, a large-scale, practice-based study in 10 countries, evaluated the effects of telmisartan alone or with hydrochlorothiazide (HCTZ) on morning (06:00 – 11:59) home blood pressure (HBP) control. Hypertensive patients (clinic blood pressure [BP] 140/90 mmHg) received telmisartan 40 or 80 mg either alone or in combination with HCTZ 12.5 mg for 8 weeks. Treatment could be adjusted if clinic BP remained 140/90 mmHg. Clinic BP was measured in the morning prior to medication, and seated HBP monitoring was performed, three times per day, 2 days per week. A total of 25,882 patients were included (71% were previously using antihypertensives). There was a statistically signifi cant (all p 0.00…
Iterative Learning Applied to Hydraulic Pressure Control
2018
This paper addresses a performance limiting phenomenon that may occur in the pressure control of hydraulic actuators subjected to external velocity disturbances. It is demonstrated that under certain conditions a severe peaking of the control error may be observed that significantly degrades the performance of the system due to the presence of nonlinearities. The phenomenon is investigated numerically and experimentally using a system that requires pressure control of two hydraulic cylinders. It is demonstrated that the common solution of feed forwarding the velocity disturbance is not effective in reducing the peaking that occurs as a result of this phenomenon. To improve the system perfor…
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 …
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…