The cycles of the steam-injection gas-turbine systems are studied. The analyses of the parametric effects and the optimal operating conditions for the steam-injection gas-turbine (STIG) system and the regenerative steam-injection gas-turbine (RSTIG) system are investigated to ensure the maximum performance. Using the analytic model, the performance parameters of the system such as thermal effic...

OBJECTIVE To assess adherence to a ventilator care bundle in an intensive care unit and to determine the impact of adherence on the rates of ventilator-associated pneumonia. METHODS A total of 198 beds were assessed for 60 days using a checklist that consisted of the following items: bed head elevation to 30 to 45º; position of the humidifier filter; lack of fluid in the ventilator circuit; o...

BACKGROUND Frequent ventilator circuit changes are expensive and sometimes unnecessary. Following the worldwide trend to lengthen the intervals for ventilator circuit change from 2 days to 1 week, this study aims to assure that low rate of ventilator-associated pneumonia (VAP) can be maintained with cost containment. METHODS Ventilator circuits were routinely changed every 7 days in the study...

Abstract: In modern wind farms, maximum power point tracking (MPPT) is widely implemented. Using the MPPT method, each individual wind turbine is controlled by its pitch angle and tip speed ratio to generate the maximum active power. In a wind farm, the upstream wind turbine may cause power loss to its downstream wind turbines due to the wake effect. According to the wake model, downstream powe...

Understanding and characterization of wind turbine dynamics, especially when operating, is an important though challenging task. The main problem is that an operating wind turbine cannot be truly modeled as a time invariant system, which limits the applicability of conventional well-established modal analysis methods. This paper compares two experimental techniques that characterize the dynamic...

An experimental study was conducted to characterize the dynamic wind loads and evolution of the unsteady vortex and turbulent flow structures in the near wake of a horizontal axis wind turbine model placed in an atmospheric boundary layer wind tunnel. In addition to measuring dynamic wind loads (i.e., aerodynamic forces and bending moments) acting on the wind turbine model by using a high-sensi...

Sediment erosion not only reduces efficiency and life of hydropower turbines but also causes problems in operation and maintenance. Several factors are responsible for this erosion in hydro turbine components. This paper presents the sediment erosion types in hydraulic turbines and their components based upon an extensive literature review and the field observation at Cahua hydropower plant, Pe...

BACKGROUND Wind turbine noise exposure and suspected health-related effects thereof have attracted substantial attention. Various symptoms such as sleep-related problems, headache, tinnitus and vertigo have been described by subjects suspected of having been exposed to wind turbine noise. OBJECTIVE This review was conducted systematically with the purpose of identifying any reported associati...

Wind turbines reliability is affected by stochastic factors in the turbulent inflow and wind turbine structures. On one hand, the variability in wind dynamics and the inherent stochastic structures result in random loads on wind turbine rotor and tower. On the other hand, the inherent structural uncertainties caused by imperfect control of manufacturing process introduce unpredictable failures ...

The wind turbine foundation serves as a permanent construction in the harsh marine corrosive environment, its anticorrosion design is essential to the safe use of the wind turbine structure. At present, there is a significant controversy over the local corrosion mechanism (such as pitting corrosion, and crevice corrosion) and its diffusion mechanism in the academic circle. In the paper, the Far...