This research reports on the experimental verification of an enhanced energy conversion device utilizing a tuned inerter called a tuned inertial mass electromagnetic transducer (TIMET). The TIMET consists of a motor, a rotational mass, and a tuning spring. The motor and the rotational mass are connected to a ball screw and the tuning spring interfaced to the ball screw is connected to the vibrating structure. Thus, vibration energy of the structure is absorbed as electrical energy by the motor. Moreover, the amplified inertial mass can be realized by rotating relatively small physical masses. Therefore, by designing the tuning spring stiffness and the inertial mass appropriately, the motor can rotate more effectively due to the resonance effect, leading to more effective energy generation. The authors designed a prototype of the TIMET and conducted tests to validate the effectiveness of the tuned inerter for electromagnetic transducers. Through excitation tests, the property of the hysteresis loops produced by the TIMET is investigated. Then a reliable analytical model is developed employing a curve fitting technique to simulate the behavior of the TIMET and to assess the power generation accurately. In addition, numerical simulation studies on a structure subjected to a seismic loading employing the developed model are conducted to show the advantages of the TIMET over a traditional electromagnetic transducer in both vibration suppression capability and energy harvesting efficiency.
In this study, the effectiveness of an oscillating-body WEC with a tuned inerter (TI) proposed by the authors is shown through wave flume testing. The TI mechanism consisting of a tuning spring, a rotational inertial mass, and a viscous damping component is able to increase energy absorption capability by taking advantage of the resonance effect of the rotational mass. This mechanism has been recently introduced for civil structures subjected to external loadings such as earthquakes and winds to decay vibration response immediately. The authors applied this mechanism to oscillating-body WECs and showed that the proposed WEC increased the power generation performance and broadened the effective frequency range without increasing the mass of the buoy itself through numerical simulation studies. To verify the validity of the proposed WEC experimentally, a small-scale prototype of the proposed device is designed and wave flume testing is carried out with various regular wave inputs of different frequencies. The results show that the WEC with the properly adjusted TI mechanism demonstrates better power generation performance compared to the conventional WEC over a wide range of wave frequencies.
A new ternary layered carbide, ZrAl8C7, has been synthesized and characterized by X‐ray powder diffraction. The crystal structure was determined using direct methods, and further refined by the Rietveld method. The crystal is trigonal (space group R3m, Z=3) with lattice dimensions a=0.332842(2) nm, c=5.78221(2) nm, and V=0.554754(4) nm3. The sample prepared was composed mainly of ZrAl8C7 with a small amount of ZrAl4C4. These two types of carbides have been found to form a homologous series with the general formula (ZrC)mAl8C6, where m=1 and 2. They show comparable intergrowth structures consisting of [ZrmCm+1] layers separated by [Al8C7] layers.
Zirconium I 4400 [Zr0.72Y0.28]Al4C4: A New Member of the Homologous Series (MC)l(T4C3)m (M: Zr, Y and Hf, T: Al, Si and Ge). -The new layered title carbide is prepared from a mixture of ZrC, YC2, and Al4C3 in the molar ratio 5:5:11 (Ar, 2273 K, 30 min) and characterized by powder XRD, TEM, and EDX. Zr0.72Y0.28Al4C4 crystallizes in the trigonal space group P3m1 with Z = 1. The structure contains [Zr0.72Y0.28C2] thin slabs separated by [Al4C4] layers. The carbide is the first member of the title series with l = 1 and m = 1. -(SUGIURA, K.; IWATA, T.; NAKANO, H.; FUKUDA*, K.; J. Solid State Chem.
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