نتایج جستجو برای: critical pitch angle
تعداد نتایج: 624126 فیلتر نتایج به سال:
The question of the value of the pitch angle of DNA is visited from the perspective of a geometrical analysis of transcription. It is suggested that for transcription to be possible, the pitch angle of B-DNA must be smaller than the angle of zero-twist. At the zero-twist angle the double helix is maximally rotated and its strain-twist coupling vanishes. A numerical estimate of the pitch angle f...
In this paper, a comparative assessment is made based on time domain specifications and erro r criteria between various types of controllers like conventional PID, and heuristic approaches like FA, P SO and BFO based PID and I-PD structured controllers. The dynamic modelling of pitch control system i s considered on the design of an auto pilot that controls the pitch angle. To study the effecti...
A precision spin stand was used to study the effects of pitch static angle and roll static angle on lubricant transfer between a disk and a slider in a hard disk drive. The lubricant distribution on the slider was determined by timeof-flight secondary ion mass spectrometry, while the lubricant distribution on the disks was obtained using optical surface analysis. Lubricant transfer from the dis...
Van Allen radiation belts consist of relativistic electrons trapped by Earth's magnetic field. Trapped electrons often drift azimuthally around Earth and display a butterfly pitch angle distribution of a minimum at 90° further out than geostationary orbit. This is usually attributed to drift shell splitting resulting from day-night asymmetry in Earth's magnetic field. However, direct observatio...
A data-driven approach for maximization of the power produced by wind turbines is presented. The power optimization objective is accomplished by computing optimal control settings of wind turbines using data mining and evolutionary strategy algorithms. Data mining algorithms identify a functional mapping between the power output and controllable and non-controllable variables of a wind turbine....
One of the main tasks of the control systems in the wind turbines is to maintain the power of the wind when its wind speed proceed its nominal value. Because the failure to maintain the power in its nominal value in the region of the turbine curve damages the turbine and increases the mechanical stress. This object is obtained by controlling the pitch angle in the third region of the turbine cu...
Good alignment of the magnetic field line pitch angle with the mode structure of an external resonant magnetic perturbation (RMP) field is shown to induce modulation of the pedestal electron pressure p(e) in high confinement high rotation plasmas at the DIII-D tokamak with a shape similar to ITER, the next step tokamak experiment. This is caused by an edge safety factor q95 resonant enhancement...
The feasibility of using a motion sensor to replace a conventional electrolarynx(EL) user interface was explored. Forearm motion signals from MEMS accelerometer was used to provide on/off and pitch frequency control. The vibration device was placed against the throat using support bandage. Very small battery operated ARM-based control unit was developed and placed on the wrist. The control unit...
The goal of this work is to develop low order dynamical systems models for the unsteady aerodynamic forces on small wings and to better understand the physical characteristics of unsteady laminar separation. Reduced order models for a fixed, high angle of attack flat plate are obtained through Galerkin projection of the governing Navier-Stokes equations onto POD modes. Projected models are comp...
In this paper, dynamic modeling of a Vestas 660 kW wind turbine and its validation are performed based on operational data extracted from Eoun-Ebn-Ali wind farm in Tabriz, Iran. The operational data show that the turbine under study, with a classical PI controller, encounters high fluctuations when controlling the output power at its rated value. The turbine modeling is performed by deriving th...
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