Este libro presenta las diversas facetas de la química: la formación del universo, la constitución de la tierra, el origen de la vida, la medicina, la música y las huellas de actividades humanas.
A ground acceleration map is needed as a consideration in building construction. Therefore, a good ground motion attenuation model is needed to predict the condition in the field properly. This study discusses ground motion attenuation... more
A ground acceleration map is needed as a consideration in building construction. Therefore, a good ground motion attenuation model is needed to predict the condition in the field properly. This study discusses ground motion attenuation models that are appropriate for West Sumatra and Bengkulu based on distant subduction interface and intraslab earthquakes from 9 attenuation models. The ground motion data in this study are from 13 Meteorological, Clima-tological, and Geophysical Agency's (BMKG) accelerograph sensors that are located in West Sumatra and Bengkulu regions from 2012 to 2017 with a distance of less than 1000 km from the earthquake sources, magnitude range of 4.1-6.4 for subduction interface earthquakes, and 4.1-6.5 for subduction intraslab earthquakes. The results show that the ground motion attenuation model from Kanno et al. (2006) has the best result with an RMSE value of 0.46 for subduction interface earthquakes and the model from Bernal et al. (2012) with RMSE value of 0.49 for subduction intraslab earthquakes.
According to the planetary origin conceptual model proposed in this paper, the protosun centre of the pre-solar nebula exploded, resulting in a shock wave that passed through it and then returned to the centre, generating a new explosion... more
According to the planetary origin conceptual model proposed in this paper, the protosun centre of the pre-solar nebula exploded, resulting in a shock wave that passed through it and then returned to the centre, generating a new explosion and shock wave. Recurrent explosions in the nebula resulted in a spherical standing sound wave, whose antinodes concentrated dust into rotating rings that transformed into planets. The extremely small angular momentum of the Sun and the tilt of its equatorial plane were caused by the asymmetry of the first, most powerful explosion. Differences between inner and outer planets are explained by the migration of solid matter, while the Oort cloud is explained by the division of the pre-solar nebula into a spherical internal nebula and an expanding spherical shell of gas. The proposed conceptual model can also explain the origin and evolution of exoplanetary systems and may be of use in searching for new planets.
In the current paper, we further improved the model for the migration of planets introduced and extended to time-dependent planetesimal accretion disks by Del Popolo. In the current study, the assumption of Del Popolo, that the surface... more
In the current paper, we further improved the model for the migration of planets introduced and extended to time-dependent planetesimal accretion disks by Del Popolo. In the current study, the assumption of Del Popolo, that the surface density in planetesimals is proportional to that of gas, is relaxed. In order to obtain the evolution of planetesimal density, we use a method developed by Stepinski and Valageas which is able to simultaneously follow the evolution of gas and solid particles for up to 10 7 years. Then, the disk model is coupled to migration model introduced by Del Popolo in order to obtain the migration rate of the planet in the planetesimal. We find that the properties of solids known to exist in protoplanetary systems, together with reasonable density profiles for the disk, lead to a characteristic radius in the range 0.03-0.2 AU for the final semi-major axis of the giant planet.Hence our model can explain the properties of discovered extrasolar giant planets.
