After the Great East Japan Earthquake devastated the Fukushima Daiichi nuclear power plant, many nuclear plants in Japan have been closed and now we depend on fossil fuel. The lack of energy will be better to be compensated by solar power and wind power, which are directly affected by the weather. Therefore, the output remains unstable. This study focuses on the tidal power generation system, which is not much affected by the weather, to build it up as the small hydroelectric system which can generate a stable power. The system is multi-level and each level is a combination of Savonius type hydraulic turbine and Darrieus type hydraulic turbine, which are mostly used in tidal power generation systems. Therefore, we can obtain a stable and more efficient power even at low tidal speed current. We carried out research on efficiency of turbines under low current such as rivers and agriculture canals in order to choose the best type of them.
There are some non-destructive methods for estimating a depth of reinforcing steel bars in concrete structure. In this paper, we propose a technique for estimating the depths of reinforcing steel bars through the analysis using FEM and experiments. Reinforcing steel bars are magnetized by using pulse magnetization method. The spatial distribution of magnetic flux densities BX, BY, BZ at the surface of concrete structures are measured. Two reinforcing steel bars are magnetized by using the pulse magnetic field in the same direction and the opposite direction. Magnetic flux densities BY and BZ are measured for estimating the depth of reinforcing steel bars. We have confirmed that the depth of reinforcing steel bars is estimated by using our proposed method. Furthermore, FEM analysis is performed for the experiment. The depth of the reinforcing steel bars is found to be estimated by using FEM. Relationship between the real depth by using experiments and the estimated depth by using FEM are discussed in our paper.
Pulse YAG lasers has been widely utilized in the field of estimation system of nonlinear optical crystals. In the case of bulk samples, the detected second harmonic signals with high SN ratio can be easily detected. However, in the case of liquid samples, its signals become very weak due to the electromagnetic noise of YAG laser i.e. Q switching. Then the measurement with enough SN ratios is difficult. To detect the second harmonic signals having enough SN ratios, this paper proposes a photo detector with time delay. This detector has the function such that Q switching noise and photo signal are mutually separated. Experimental result demonstrates effectiveness of the proposed photo detector which is applied in the industrial fields.
We propose a singing system to transmit the pseudo-vocal sound source into the vocal tract. In this paper, we examine the pseudo-vocal sound source that is suitable for singing system. So we carried out a comparison of LPC residual wave and Bark-LPC residual wave that the phonological component included in pseudo-vocal sound source was removed by Bark spectrum. As a result, we found that although the singing voice using Bark-LPC residual is in the low natural tendencies, the Bark-LPC residual wave can reproduce a higher speaker information contributed by the speaker characteristics.
Underactuated manipulators have some passive joints in general, where the number of inputs is less than the degrees of freedom. These systems have complex properties in structure and they have to control a lot of generalized coordinates by few inputs. In this paper, we propose a switching control method for three-DOF underactuated manipulators. Then, we convert a system of underactuated manipulator to one applied extend nonholonomic double integrator form. Here we need to decide gain parameters for the controller using our proposed method. Therefore we try to apply these parameters which were optimized by genetic algorithm (GA). The effectiveness of the proposed method is illustrated through simulations.
Boron-doped ultrananocrystalline diamond (UNCD) amorphous carbon (a-C) composite films were fabricated by a coaxial arc plasma deposition (CAPD) method. Cyclic voltammetry measurements of deposited films showed wide electrical potential window and very low background current, which remarkably similar to conductive poly crystalline diamond (PCD) electrodes. In addition, it was confirmed that deposited films have removal effects of total organic carbon (TOC) in an ethanol water solution. Boron-doped UNCD/a-C films have potential for behaving as an electrode with wastewater treatment effects.