[en] The effect of earth quake to landslide stability and run out distance on landslide zones in West Java-Indonesia during rainfall was investigated considering different slope angle. An earthquake peak ground acceleration 0.3 gal for 20 s is applied on landslide zones under a rainfall intensity of 10mm/h for 4 hour. In this study, the slope angles of 26°, 33°, 45°, 56° and 68° are considered. We found that the safety factor decreases as the slope angle increases. With the introduction of rainfall and earthquake, the safety factor of the slope drops below 1.0 at slope angle higher than 33°. The calculations of run out distance during rainfall and earthquake shows the landslide masses generated from the slope 45° will travel more than slope 68° for the same soil characteristic. This is due to the landslide masses from the slope 45° is smaller than that from in the slope of 68°. We found that combination rainfall and earthquake makes the stability of the slope smaller than due to rainfalll alone. However, the run-out distance of landslide masses due to the combination of rainfall and earthquake has no significant different when compared with due to rainfall alone. (paper)

[en] An andesite rock sample was taken from potential geothermal area on Lili-Sepporaki, west Sulawesi. The sample is an impermeable cap rock with a high silica mineral at alteration zone around a manifestation. Its Three-dimensional rock structure was analyzed to see its deformation due to temperature change. Change of temperature from 24˚C to 100˚C, 150˚C, 200˚C, and 250˚C was applied to the sample. Subsequent to each change of temperature, the sample was scanned using a micro-Computed Tomography Scan (μ-CT Scan). From the scanning process, a sub-volume 300 pixels were reconstructed, and its 3D pore and mineral structure were characterized. It is found that porosity {φ (T)}, specific surface area {SsA (T)} decrease polynomial for pore structure and increase polynomial as temperature increases. This result show that as temperature increases the volume of mineral is bigger make the pore volume smaller. The Fractal dimension for pore structure (2.65 ± 0.02) and for mineral structure (2.89 ± 0.015). (paper)

[en] We study two (4+n)-dimensional branes embedded in (5+n)-dimensional spacetime. Using the gradient expansion approximation, we find that the effective theory is described by (4+n)-dimensional scalar-tensor gravity with a specific coupling function. Based on this theory we investigate the Kaluza-Klein two-brane-worlds cosmology at low energy, in both the static and the nonstatic internal dimensions. In the case of the static internal dimensions, the effective gravitational constant in the induced Friedmann equation depends on the equations of state of the brane matter, and the dark radiation term naturally appears. In the nonstatic case we take a relation between the external and internal scale factors of the form b(t)=a^γ(t) in which the brane world evolves with two scale factors. In this case, the induced Friedmann equation on the brane is modified in the effective gravitational constant and the term proportional to a^-4β. For dark radiation, we find γ=-2/(1+n). Finally, we discuss the issue of conformal frames which naturally arises with scalar-tensor theories. We find that the static internal dimensions in the Jordan frame may become nonstatic in the Einstein frame.

[en] The brane-world cosmological model in higher-dimensional spacetime with a bulk scalar field is investigated. We derive the (4+n)-dimensional gravitational field equations for the scalar field on the (3+n)-brane in a (5+n)-dimensional bulk with Einstein gravity plus a self-interacting scalar field. The (4+n)-dimensional gravitational field equations can be formulated to standard form with the extra component. Using this formalism we study the Kaluza-Klein brane cosmology. We derive the Friedmann equation and a possible energy leak out of the brane into the bulk. We present some exact solutions corresponding to vacuum brane and matter on the brane.