Wind turbines are in the limelight in the alternative energy industry. However, they face frequent and various problems during operation. We focused on the supervising of the blades of a wind turbine. In this paper, we present the design of a maintenance robot that takes the size of wind turbine blades into consideration, so the general form of the robot is a square with four wires fixed to its vertices and to the nacelle. After the robot is placed near the nacelle, it moves along the blades. We also designed an attitude control algorithm for the robot to maintain its balance. Our control algorithm for the robot consists of roll and pitch attitude controllers and a height controller. Each controller was designed independently and then superposed together. We used simulations to verify our control algorithm.

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This paper presented the strength and environmental characteristics of reclaimed-ground filled with controlled lowstrength materials (CLSM) made of coal ash, small amounts of cement, and water in a reclamation site and evaluated the possibility of the use of coal ash on reclamation materials for beneficial use. Three-month period of SPT, CPT, environmental effects evaluation etc. were conducted. N values and cone resistances in ground filled with CLSM were greater than or similar to those in dredging sand. In case of land filled with coal ash except cement these values were lower than those in dredging sand. The results of soil and seawater pollution were lower than test criteria without high

The determination of in-situ capping materials is one of the most important factors to design in-situ capping in order to protect capping materials from erosion. Previous studies have established relationship between the velocity induced by wave energy and effective diameter of sediments, but they are mostly empirical and numerical researches which is too complicated for field engineers to analyze the erosion of in-situ capping materials. This study provides simple analytical solutions and reliability based on hydraulic model test results. Experimental results show that measured flow velocities with respect to depth induced by wave energy are almost the same as estimated velocities and the erosion resistances of the different effective particle diameters can be estimated.

In-situ capping is a method to stabilize contaminated sediments by isolation. Few researches on the in-situ capping have been performed, although the engineering approach is still required to prevent the release of contaminants. In this study, hydraulic model test were conducted by using a wave generator to observe the change of cap thickness which is important factor in design of capping. Sands with particle size between 0.075 to 2 mm as capping materials were used to observe the change of capping thickness by waves. The experimental results show that the surface of capping materials is similar to wave form. The more wave height increases, the more erosion of capping materials increases.