The wave energy power generation-pendulum system (WEPG-PS) is a four-wheeled instrument designed to convert wave power into electric energy. The first wheel is connected to the pendulum by a double freewheel, the second and third are ordinary wheels, while the fourth is a converter component that is axially connected to the electric generator. This design used the Euler-Lagrange formalism and Runge-Kutta method to examine an ideal dimension and determine the numerical solution of the equation of motion related to the rotation speed of the wheels. The result showed that the WEPG-PS' converter system rotated properly when its mass, length, and moment of inertia are 10 kg, 2.0 m, and 0.25 kgm2, respectively. This is in addition to when the radius of the first, second, third, and fourth wheels are 0.5, 0.4, 0.2, and 0.01 m, with inertia values of 0.005, 0.004, 0.003, and 0.1 kgm2. The converter system has the ability to rotate the fourth wheel, which acts as the handle of an electric generator at an angular frequency of approximately 500 - 600 rad/s. The converter system is optimally rotated when driven by a minimum force of 5 N and maximum friction of 0.05. Therefore, the system is used to generate electricity at an amplitude of 0.3 - 0.61 m, 220 V with 50 Hz. Besides, the lower rotation speed and frequency of the energy converter of the WEPG-PS (300 rad/s) and induction generator (50 Hz) were able to generate electric power of 7.5 kW. ©2020. CBIORE-IJRED. All rights reserved

We study the parameterization of cosmological model where derivative of an additional scalar field coupled to curvature tensor. We extend the Parameterized Post-Friedmannian framework for interacting dark energy theories to the model. Starting from general cosmological perturbation metric, we derive perturbed energy-momentum tensor for scalar field and parameterized the tensor. Based on the value of the parameters, we compare the model with relevant models in current literature. As the results, we find that parameterization for type 1 theories of dark energy which is explicitly coupled to dark matter, gives only 4 non-zero Parameterized Post-Friedmannian coefficients.

Pico hydropower is a type of hydropower that can produce electric power under or equal to 5000 Watt. Consisting of one turbine to rotate one generator, it has been used in remote areas to provide for electricity supply. Although the system serves quite well, sometimes the necessity for electricity supply is larger than the system can supply. The solution would be to build two pico hydropower systems. However, the cost of such a solution will also double. In addition to that, the water source and landscape may not sustain more than one pico hydropower. An alternative solution that is being proposed to resolve the problem is by using one turbine to rotate two electric generators in a unity pico hydropower system. The objective of the study concerning the proposed solution is to obtain a configuration and dimension of the energy converter. They are sought by determining the equation of motion for energy converter which is configured in several wheels. The equation of motion, which is in differential form, is obtained using the Euler-Lagrange procedure in classical mechanics. Both configuration and dimension of energy converter are solved using numerical methods. The numerical method used in this study is the fourth-order of the Runge-Kutta method for analyzing some physical parameters i.e.: angular velocity of the energy converter, friction coefficient, driving force, radius and inertia of the wheels. By employing varying numbers in the computational process using the fourth-order of the Runge-Kutta method in Matlab, we seek that the pico hydropower system with ideal configuration and dimension of energy converter based on the radius of the wheels are configured as r 1> r 3>r 2>r 4>r 5=r 6. The configuration yield an optimum rotation of the coupled wheels (r 5 and r 6) as a representation of the electric generator’s axis although the thrust is assumed lower. The design expected to be a solution for optimizing a pico hydropower, especially in remote areas with lower water flow.

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In general relativity, a gravitational wave propagates with the speed of light, but inthe alternative theories of gravity, propagation speed could deviate from the speed of lightdue to the modification of gravity. Gravitational waves are influenced by modified gravityduring propagation at the cosmological distance. In this paper, we investigate thepropagation of a gravitational wave of the generalized Proca theories by consideringgravitational wave as the gravitational field propagates in spacetime as a wave perturbing flatspacetime. We show that the arbitrary functions G3, G4, and G5 can be the sources ofdeviation of the speed of the gravitational wave.