The maintenance cost of wind turbines has become the significant challenge for the wind power enterprise. One available way to reduce the cost is to monitor the wind turbines and make preventative maintenance. In this paper, an on-line condition monitoring system for wind turbines in plant level was presented. A 4-level monitoring structure was designed for the system, and the network communication was used to transmit the data efficiently. A high performance digital signal processor (DSP) was used as the processing core in the signal acquisition device. A computer software was also developed for data analysis and remote management of the monitoring device. The vibrations, temperature, and some other information of the turbines were gathered synchronously. The monitoring center in wind farm, the data center of wind power enterprise and the remote service center of equipment supplier can know the operation condition of wind turbines well. It would be useful for wind power enterprise to obtain the operation condition of wind turbine and reduce the cost of maintenance.

Ni-ZrO 2 nanocomposite coatings were fabricated by electrodeposition from a modified Watt’s type electrolyte containing ZrO 2 nanoparticles, where an ultrasonic field was imposed during electrodeposition process. The weight percent of ZrO 2 in coatings and the surface morphology of coatings were examined. The microhardness and tribological properties of Ni-ZrO 2 nanocomposite coatings and pure Ni coating were investigated. The results show that ultrasonic agitation can greatly affect the microstructure and the tribological behavior of Ni-ZrO 2 nanocomposite coatings. The Ni-ZrO 2 nanocomposite coatings record variable ZrO 2 contents and surface morphologies by modifying ZrO 2 concentration in electrolyte and ultrasonic parameters. The Ni-ZrO 2 nanocomposite coating fabricated with ultrasonic agitation exhibits finer grains and more compact structure compared to pure Ni coating and the Ni-ZrO 2 nanocomposite coating fabricated without ultrasonic agitation. The dispersed ZrO 2 nanoparticles in coatings and ultrasonic agitation during electrodeposition synthetically contribute to the grain refinement of the coatings. Therefore, the Ni-ZrO 2 nanocomposite coating by ultrasonic electrodeposition exhibits high microhardness and excellent tribological behavior. In general, the improvement in friction and wear properties of Ni-ZrO 2 nanocomposite coatings can be attributed to the homogeneously dispersed ZrO 2 nanoparticles and the finer-grained structure.

To predict the dynamic stresses due to forced response of steam turbine blades, a commercial FE solver ABAQUS has been linked with an in-house CFD solver TF3D-VIB, in the time domain in both one-way and two-way coupling. Both methods have been applied to analyse a freestanding subsonic turbine stage excited by upstream flow perturbations. Over a frequency range the peak responses are very similar, but the peak response of two-way coupling is shifted to a lower frequency, due to the aerodynamic coupling effect of fluid-structure interaction. That means a speed / frequency sweep is necessary to search for the peak response in two-way coupling. However, in one-way coupling, the frequency shift can be derived from the vibration induced modal force, and only one calculation is needed to predict the response over a range of frequency ratio using the classic single degree-of-freedom equation. One calculation using two-way coupling typically takes seven times more computing time than one-way coupling. The total computing time for two-way coupling to define the response characteristic is therefore much higher; more calculations are needed and each calculation takes much longer. Thus a one-way coupling method including the frequency shift correction is much more practical and suitable for blade design iterations. The blade forced response is also limited by damping. In the case of low damping such as material only damping, this can be well represented in the harmonic ABAQUS calculation. However, high values of nonlinear damping can be deliberately introduced by managing the friction forces at blade root attachment. The nonlinear damping can be simulated directly by ABAQUS/Explicit method, convergence criteria often lead to excessive runtimes. Therefore a simple mass/spring model has been developed, which applies an exciting force to a system comprising two masses and springs to represent the blade and the root respectively and includes modelling of both the stick and slip forces of the root due to friction. Both the masses and their spring stiffness are chosen to produce either the sticking natural frequency (with infinite friction) or sliding natural frequency (zero friction). Using the simple two-mass model, the significant nonlinear response pattern is demonstrated. The resulting pattern has been verified against the ABAQUS/Explicit method. This allows the blade forced response prediction from the one way coupling to be further corrected to account for the nonlinear friction damping effect.

Separation of cancer cells from the other biological cells is important for clinical cancer diagnosis and cancer treatment. In this presentation, we use conventional dielectrophoresis (c-DEP) in a microfluidic chip to manipulate and collect colorectal cancer HCT116 cell. It is noticed that at particular AC frequency band, the HCT116 cell are deflected to a side channel from a main channel clearly after the electric activation. This motion caused by negative DEP can be used to separate the cancer cell from others. In this manuscript, we report the chip design, flow condition, the DEP spectrum of the cancer cell, and the separation and collection efficiency as well.