The ability of variable speed wind turbines technology to optimally tracking the power from wind energy has become the main reason of their popularity compared with the fixed speed wind turbines. In the earlier stage ...
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The ability of variable speed wind turbines technology to optimally tracking the power from wind energy has become the main reason of their popularity compared with the fixed speed wind turbines. In the earlier stage of connecting wind turbines (WTs) to the existing electricity grids, WTs were allowed to be disconnected from the grid in case of grid faults which might lead to the damage of the turbines. However, recently, the transmission system operators (TSOs) require to maintaining the connection of WTs with the grid to support the grid during fault and to assure the continuity of power supply. This requirement has been compiled in new grid codes in several countries. In this paper, super conducting magnetic energy storage (SMES) unit is used with two different types of variable speed wind turbine generators to comply with Spain grid codes. Results show that the low-voltage-ride-through (LVRT) of Type-3 and Type-4 wind turbine generators are significantly improved when SMES unit is connected to the system.
We successfully engineered Si nano-columns with different cross-sectional geometries by e-beam evaporation with an angle between source and substrate. The Si nano-columns were grown as pillars with square, triangle an...
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Variable speed wind turbine with full scale converter or so-called type-D wind turbine generator worldwide installation has been significantly increased in the last few years. Voltage Swell in the grid side may cause ...
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Variable speed wind turbine with full scale converter or so-called type-D wind turbine generator worldwide installation has been significantly increased in the last few years. Voltage Swell in the grid side may cause the wind turbine to be disconnected from the grid. In this paper, STATCOM is applied to improve the high voltage ride through capability of type-D wind turbine during voltage swell in the grid side. Simulation is carried out using MATLAB/Simulink software. Results show that STATCOM can significantly improve the high voltage ride through (HVRT) capability of type-D wind turbine and prevents it from being disconnected from the grid during certain level of voltage swell in the grid side.
We report on self-organized solid-phase epitaxially grown Ti- and Co-silicide nanoislands ordered along step-bunch edges of a vicinal Si(111) surface, as a function of the initial metal (Ti,Co) coverage. While the deg...
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We report on self-organized solid-phase epitaxially grown Ti- and Co-silicide nanoislands ordered along step-bunch edges of a vicinal Si(111) surface, as a function of the initial metal (Ti,Co) coverage. While the degree of self-ordering (in terms of step decoration) for Co-silicide islands was higher than for Ti-silicide islands, both types of island had an inverse dependence of the order parameter on coverage. In addition, the positions of the island sites were found to be correlated, and affected by the step-island and island-island interactions, leading to their alignment along the step-bunch 〈110〉 directions, even for the terrace islands. Aberration-corrected high-resolution transmission electron microscopy was used to characterize the islands’ crystal structure and growth orientation. The above findings can be understood by the use of coarse-grain modeling.
We successfully engineered Si nano-columns with different cross-sectional geometries by e-beam evaporation with an angle between source and substrate. The Si nano-columns were grown as pillars with square, triangle an...
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We successfully engineered Si nano-columns with different cross-sectional geometries by e-beam evaporation with an angle between source and substrate. The Si nano-columns were grown as pillars with square, triangle and linear cross sections in in-plane. Mesenchymal stem cells (MSCs) isolated from the bone marrow stroma of young adult rats were cultured on these different Si nanosurfaces. We found that the behaviour of MSCs highly depended on the geometry of nano-topography so that mesenchymal stem cells were differentiated and induced CaP precipitation on square-cross-sectional Si nano-columns without growth factor in the culture medium.
A novel model reduction strategy for forced dissipative infinite-dimensional nonlinear dynamical systems is described. Unlike popular but empirical methods, this new approach does not require extensive data sets from ...
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One of games used as educational media is in hajj learning since Indonesia is well known as a country with the biggest hajj pilgrims every year. This research developes a HajjGame that provides a series of phase of th...
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An offshore riser system presents vortex induced vibrations when it is exposed to sea current, ocean waves and it is forced at the sea surface by a floating platform motions. The Vortex Induced Vibration (VIV among ot...
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Gas permeability and intrinsic permeability are the major parameters to promote aeration for packed waste. The objectives of this research are to identify physical parameters of gas transfer from a various type of pac...
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Gas permeability and intrinsic permeability are the major parameters to promote aeration for packed waste. The objectives of this research are to identify physical parameters of gas transfer from a various type of packed wastes and examine ventilation design theory for landfill to enhance waste stabilization. Method to determine value of gas permeability and intrinsic permeability for packed waste is by flushing the packed column containing various type and physical characteristics of wastes with an air pump. Permeability was calculated by measuring pressure gradient on sampling points of the column using inclined manometer at distance 10 cm, 23 cm, 46 cm, 69 cm, 92 cm and 115 cm from origin. Gas permeability is specifically relied on physical parameters of wastes as follows, density, moisture content, particle size and gas velocity on the surface of compacted waste layer. Compost has finer pore structure and smaller pore size than leaves as well as mixed organic (65%) and inorganic wastes (35%). The experiment found the intrinsic permeability of leaves waste are in the order of 10-11 to 10-8 m2, 10-11 to 10-9 m2 for compost and 10-9 m2 for mixed organic (65%) and inorganic wastes (35%).
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