Research on wind turbine technologies have focused primarily on power cost reduction. Generally, this aim has been achieved by increasing power output while maintaining the structural load at a reasonable level. However, disturbances, such as wind speed, affect the performance of wind turbines, and as a result, the use of various types of controller becomes crucial.This paper deals with two ada...

Introduction. Individual cigarettes are point sources of air pollution; smoking in groups becomes an area source. Outdoor air pollutants from individual point sources are subject to plume rise if the temperature of the smoke plume is hotter than the surrounding air; however if the plume has a small cross-section, as for a cigarette, it will rapidly cool and lose its upward momentum, and then wi...

While the fast solar wind is nerally thought to originate from coronal holes, the ~, Oa% source of the slow solar wind is only known to be associated with the highly structured and — highly variable streamer belt. There is growing evidence from multiple-station intensity scintillation measurements of solar wind velocity — usually referred to as IPS for interplanetary scintillation— that the slo...

A major outstanding problem in stellar astrophysics lies in understanding the wind generation mechanism by which evolved giants lose mass. Phase-resolved observations of eclipsing symbiotic binary systems, containing a mass-losing giant and a hot white dwarf, are ideal for studying the wind generation mechanisms in evolved stars. For such systems we use the orbital motion of the dwarf through t...

The wind energy is considered to be one of the poor quality energies due to the variation of the velocity and direction of the wind. These variations cause fluctuations in the input power and the frequency, thereby affecting the operation of the system. At a given wind velocity, the mechanical power available from a wind turbine is a function of its shaft speed. The shaft speed is varying due t...

A wind tunnel investigation was performed to study the flow field over a 70° swept sharped edge delta wing model at high angles of attack. The experiments were conducted in the subsonic wind tunnel at the Department of Mechanical Engineering, Sharif University of Technology. Velocity profiles have been measured using a special pitot tube and hot wire anemometer at angles of attacks of 10 to 35 ...

Asymptotically exact and nonlocal fourth order nonlinear evolution equations are derived for two coupled fourth order nonlinear evolution equations have been derived in deep water for two capillary-gravity wave packets propagating in the same direction in the presence of wind flowing over water.We have used a general method, based on Zakharov integral equation.On the basis of these evolution eq...

One of the greatest challenges associated with wind power is the unpredictable character of the wind. Wind energy is one of the lowest-priced renewable energy technologies available today, costing between 4 and 6 cents per kilowatt-hour, depending upon the wind resource and project financing of the particular project. In our research, a design and modeling technique has been proposed to optimiz...

abstract wind erosion of soils and suspended particles in iran is one of the serious environmental and agricultural problems which affect agricultural lands, water reservoirs, irrigation canals, drains and etc. therefore wind erosion control needs attention specially in arid and semi-arid regions. although in recent years, some polymeric materials have been used for improvement of structural st...