List of Accepted manuscripts:


Modeling of Coal Deposition Using the Resistivity Method with Wenner Confifiguration in the Bentarsari Basin Area, District of Salem, Brebes Regency, Central Java
Author(s): Putri Suci Ramdani and Sehah*
Abstract: Research to model coal deposits in the Bentarsari Basin area of Salem District in Brebes Regency has been done using the geoelectric-resistivity method with Wenner confifiguration. Resistivity data acquisition is carried out on fifive tracks, with each track has a length of 200 m. The least squares inversion method is applied to obtain a 2D-resistivity section model. Furthermore, the 2D-resistivity section model data for each line is combined into a 3D model to determine the coal deposit model in the area. The results of the interpretation indicate that the subsurface structure of the area consists of clay, sandy clay, coal, and sandstone; where the type of coal is lignite. This coal deposit has resistivity values with interval of 86.1-219.0 Ωm, which is distributed evenly with depth of 0.0-26.5 m, where the southern part of the all track has a higher potential. This research
can be followed up with log drill testing to determine the actual subsurface layer, so that it can be utilized as a very economical alternative energy.

Evaluation and Analysis of Uncertainty Measurement of The Sound Level Meter Calibration by Coupler Method
Author(s):  Bondan Dwisetyo and Denny Hermawanto
Abstract: The calibration of sound level meter (SLM) using a coupler method has been introduced. This method utilizes a multifunction acoustic calibrator as a portable laboratory instrument. By the reason of its convenient application, it is appropriate to be realized by the secondary calibration laboratory. To complete the requirement of calibration result provided by ISO 17025, an analysis of the uncertainty measurement related to this calibration is strongly needed. Therefore, this work aims to provide an evaluation and analysis of some elements that inflfluence to the coupler method of SLM calibration using the statistical approximation to determine the major parameters such as standard uncertainty, combine uncertainty, degree of freedom, and expanded uncertainty in accordance with The Guide to the expressions of Uncertainty in Measurement (GUM). Moreover, a case study related to this instrument calibration also discussed along this paper. From the result, the uncertainty budgets that contribute to the SLM calibration has been obtained, and generally, it is found that the standard instrument has the highest contribution to the determination of the expanded uncertainty. For the whole results,
the obtained uncertainty values are still acceptable according to the acceptance limit values that required by IEC 61672-1.

Differences in the use of Gel Electrolytes and Liquid Electrolytes on the Performance of Dye Sensitized Solar Cells (DSSC) Prototype Based on TiO2 Nanoparticles with Mulberry (morus) Extract as Dye Sensitizer on ITO Glass Substrate
Author(s): Irmayatul Hikmah*,1 Zid Latifataz Zahrok,2 and Gontjang Prajitno2
Abstract: A prototype of Dye Sensitized Solar Cell (DSSC) based TiO2 nanoparticles and mulberry (morus) extract as dye sensitizer on the ITO glass substrate has been produced. The study aims to determine the difference between the use of gel electrolyte and liquid electrolyte on its inflfluence on DSSC performance. Sandwich cells were made consisting of a working electrode in the form of a conductive glass ITO deposited with TiO2 which was sensitized by a dye of mulberry extract, the opposite electrode in the form of a conductive glass ITO with carbon deposited, and the electrolyte in the middle of the two electrodes were liquid and one was gel. Irradiation was carried out on both samples by lighting halogen lamps. Tested the characteristics of voltage-time and current-time in both samples. The results obtained for higher voltage and current values in samples with
liquid electrolytes, but for the period of stability, the samples with gel electrolytes showed better performance.

Landslide Vulnerability Analysis Due to Earthquake Based on Seismic Vulnerability and Slope of the Slip Surface in Tritis, Yogyakarta
Author: F. Edwin Wiranata
Abstract: Tritis is a hamlet in Kulon Progo Regency, located in an area with steep slope topography making it vulnerable to landslides. Ground movement vulnerability due to earthquakes is controlled by several factors, one of which is the seismic vulnerability index whose value can be obtained through microtremor measurements by H/V analysis. In addition, the dynamic trigger factor for landslides is the slope. The slope of the surface is not always the same as the slope of the slip surface because it is observed from the surface, while the slip surface is under the soil layer and requires measurements using the geophysical method to determine the surface model. For this reason, an analysis is needed to compare the landslide vulnerability between these two factors, the slope of the surface and the slope of the slip surface. From the measurement results, there is a signifificant difference between the slope and the slope of the slip surface at the same site in the north of the slope by 15.17◦ with a seismic vulnerability index (kg) of 2.5. The distribution of seismic vulnerability index in all slopes ranges from 0.075 to 7.33, dominated by areas with slopes > 18◦ . High landslide vulnerability is in the southern and northern areas.
Study of Earthquake Activities in the Lokop-Kutacane Fault in Aceh Province, Indonesia
Author: Abdi Jihad, Vrieslend Haris Banyunegoro
Abstract:The tectonic setting of Aceh is very interesting to be studied. Despite many researches of Aceh’s tectonic setting, still there are many hidden faults waiting to be studied. One of them is Lokop-Kutacane fault which becomes active in 2020. There is an increase in frequency of earthquakes in Lokop-Kutacane fault. Magnitude-fault length analysis indicates that maximum magnitude of Lokop-Kutacane fault is M7,6 but historically it only had M6.8 in the past. CDF and PDF analysis show that the highest probability of earthquake magnitude is between 3 to 4 at 28.9%. Focal mechanism also gives two nodal planes with the direction of strike of 62 and 153. The distribution of earthquakes trend fits the 153 strike nodal plane with the direction of Northwest-Southeast. The calculation of b-value gives 0.78 that indicate that the fault is not able to hold a large amount of stress or the stress will be released in form of small to moderate earthquakes.
Effect of HAp on Characterization of MgZn-xHAp Biocomposites

Author: Henni Sitompul, Yohanes Edi Gunanto, Maya Puspitasari Izaak
Abstract:Research on Mg as biodegradable materials in orthopedics has been carry out intensively in the 17 years. Various studies conducted to produce material that is superior in mechanical properties and corrosion resistance. One of the developments carry out is to make Mg-based composite. This study aims to see the effect of HAp on Mg6ZnHAp composites. The biocomposites were synthesized by mixing the HAp powder on the Mg6Zn powder mixture with the composition of 5%, 7% and 9% using ball milling for 30 minutes. The material is sintered at 350 oC and held for one hour. Biocomposites were characterized by SEM/EDS, X-ray diffraction (XRD) and Potentiostat. The SEM/EDS results showed that the larger the HAp composition resulted in the smaller grain size. The crystallite size of the material decreases with increasing HAp composition in the material. The presence of HAp in the material also affects the corrosion rate. The greater HAp composition in the material will result in better corrosion resistance.

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