Synthesis and characterization of Ba1-xLaxFe12O19 based permanent magnet samples with variations in composition (x = 0; 0.02; 0.04; and 0.08) has been done. The method used is a solid state reaction. The phase formation of the sample Ba1-xLaxFe12O19 was carried out at 1200oC for 2 hours. The results of the X-ray diffraction pattern analysis show that all sample compositions have a single phase BaFe12O19. The results of magnetic properties testing using VSM showed that the best coercivity field and remanent magnetization values were obtained at the composition of x = 0.04. The effect of substitution of lanthanum into the barium atom can increase the number of magnetic domains which are indicated by the increase in the coercivity value of the material along with the increasing composition of x. It was concluded that the composition of Ba1-xLaxFe12O19 is a permanent magnet with the best product energy.

An investigation of risk identification earthquake disaster in Nusa Tenggara Barat by three factors: the danger factor of earthquakes is Peak Ground Acceleration(PGA), vulnerability factor is population density by district, as well as the capasity factors are HDI (Human Development Index) by district in the province of West Nusa Tenggara has be done. PGA value calculation was performed using the attenuation function Fukushima and Tanaka with earthquake parameter data from 1970 - 2014 with the criteria of magnitude ? 4.5mB, depth ? 60 km and the epicenter in the range of 7.5o - 12o and 115o-120o BT and  for disaster risk index calculation earthquake using AHP (Analytical Hierarchy Process). From the calculation of the obtained regions with earthquake disaster risk levels are highest are southern Dompu, Mataram, Bima, northern Bima Regency while the lowest West Sumbawa regency and southern Sumbawa regency.

The development of permanent magnet-based rare earth metals becomes a serious problem if the raw materials are difficult to find. The solution chosen is to utilize an oxide-based permanent magnet with little substitution of rare earth metals. In this study presented a permanent magnetic synthesis of barium hexaferrite-based oxides that were doped with La and Ce atoms. The synthesis of this material uses the wet mechanical milling technique to obtain the single phase permanent magnet system Ba1-x-yLaxCeyFe12O19 (x = 0, 0.02, 0.04 and y = 0. 0.05, 0.1). The precursor is weighed according to stoichiometric composition and is milled for 5 hours then compressed at a pressure of 7000 Psi. Sintering temperature for the formation of the barium hexaferrite phase at 1200oC for 2 hours. All samples after sintering were characterized using XRD and EDS.  A single phase is obtained on all sample compositions with a hexagonal P63/mmc structure and is supported by elemental analysis data that each substituted sample contains elements La and Ce. Lattice parameters a, b, and c appear to decrease with increasing concentrations of La and Ce doping ions with a ratio of c/a in the range of 3.93-3.94.

A research about earthquake relocation in Northern Bali Island in 2015 – 2017 using the Double Difference (DD) method has been carried out. Earthquake relocation is important to get some informations about earthquake locations with high accuracy, fault zone identification, earthquake distribution and seismic analysis. The results of the relocation indicated that there was a displacement of the location of earthquake that formed moving closer to the earthquake source namely a fault. Relocation using HypoDD program gave high accurate result indicated by the RMS residual time value close to zero e.g. 0,000 - 0.01 which mean the results of calculations and observations are closed to the real value.

Abstract. The synthesis of B2O3 flux substituted NLBCO superconductor NdBa1.75La0.25Cu3O7-∂ has been done using solid state reaction and wet-mixing methods in order to obtain homogeneous crystals and single phase. From DTA/TGA characteritations showed the synthesis process by wet-mixing requires a lower temperature than the solid state reaction in growing the superconductor NdBa1.75La0.25Cu3O7-∂. Therefore, in this research NdBa1.75La0.25Cu3O7-∂ sample calcinated at 650 o C for wet-mixing method and 820 o C for solid state reaction methods. The all samples was sintered at 950 o C for ten hours. Crystallinity of the sample was confirmed using X-ray techniques and generally obtained sharp peaks that indicates the sample already well crystallized. Search match analyses for diffraction data gave weight fractions of impurity phase of the solid state reaction method higher than wet-mixing method. In this research showed decreasing the price of the lattice parameter about 1% with the addition of B2O3 flux for the both synthesis process and 2% of wet mixing process for all samples. Characterization using scanning electron microscopy (SEM) showed the distribution of crystal zise for wet-mixing method more homogeneous than solid state reaction method, with he grain size of samples is around 150-250 nm. The results of vibrating sample magnetometer (VSM) showed the paramagnetic properties for all samples.