Spektra: Jurnal Fisika dan Aplikasinya

Journal Information
ISSN / EISSN : 2541-3384 / 2541-3392
Published by: Universitas Negeri Jakarta (10.21009)
Total articles ≅ 158
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Fajar Budi Utomo, Bondan Dwi Setyo, Maharani Ratna Palupi, Chery Chen Putri, Ninu Ragil P, Dodi Rusdjadi Te, Denny Hermanto
SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 7; https://doi.org/10.21009/spektra.071.05

Abstract:
Laminated glass is one type of glass that is commonly used for sound insulation (walls or doors). Tests related to the ability of insulating glass in Indonesia are still very rare. One of the places to do this test is the SNSU BSN Lab. This lab has a function to perform sound insulation level measurements commonly known as Sound Transmission Class (STC) and maintain to trace ability of acoustic measurements. This paper aims to describe the characteristics of Sound Transmission Loss (STL) of 12mm laminated tempered glass. The sample measurement method refers to ISO 10140-1 using two chambers (source and receiver room). Based on the results of the study, it was found that the laminated tempered glass sample was not good at reducing sound at low frequencies and tended to be good at high frequencies.
Nanda Dewi Pamungkas Siwi, Ramadhan Priadi, Puji Ariyanto
SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 7, pp 1-10; https://doi.org/10.21009/spektra.071.01

Abstract:
Flores is an island located in the north of the East Nusa Tenggara region. Formed as a consequence of very complex tectonic setting that might cause relatively high level of seismic in the region. This study aims to characterize the crust structure based on the S wave velocity model, the Vp/Vs ratio, and crustal thickness beneath the station on Flores Island. This study was using receiver function analysis method of teleseismic earthquake data with magnitude criteria ≥ 6 and epicenter distance 30⁰-90⁰. Seismic signal recorded on broadband stations three components. This study was using LBFI station. Velocity model of S wave and Vp/Vs ratio determined by using the non-linear Neighbourhood Algorithm (NA) inversion. Furthermore, the velocity and Vp/Vs ratio models will be used to obtain the depth of the migration process of the amplitude of the receiver function to depth. From the results of processing the depth of the Moho layer on the island of Flores under the LBFI station was identified as 41 km. The existence of the slab can be identified quite well that is at depth about 110 to 140 km.
Syah Nanta Maulana Ishak, Frida Ulfah Ermawati
SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 7, pp 11-28; https://doi.org/10.21009/spektra.071.02

Abstract:
Ceramics based on magnesium titanate (MgTiO3) are dielectric materials that have the potential to be used in telecommunications systems at microwave frequencies, such as filters, antennas, and signal generators. This study aims to characterize the resonant frequency and output power of (Mg0.6Zn0.4)TiO3 ceramics (abbreviated MZT04) as a dielectric resonator (DR) material in a DRO circuit and relate it to the structure, microstructure, and bulk density data of the ceramics. The MZT04 ceramics were fabricated by compacting MZT04 powder at a pressure of 2.5 MPa using a cylindrical die press of 5 mm in diameter to become pellets with the same diameter. The pellets were sintered at 1300 ℃ by varying holding time for 6, 8, and 10 h to become ceramics. Data on the structure of the ceramics were obtained from the X-Ray Diffraction (XRD) pattern with Cu-Kα radiation which showed that the three ceramics contained MgTiO3 phase, each 87.02; 90.55; and 87.40 % molar, the rest % is MgO and TiO2 rutile phases. The increase in sinter holding time has increased the unit cell volume of the MgTiO3 phase from (307.94), (308.61), to (308.94) Å3; the size of the lattice parameters (a=b, c) also increased from (5.057, 13.903) Å, (5.058, 13.903) Å, to (5.061, 13.914) Å; like wise, the bulk density increased from 2.51, 2.82, and 3.04 g/cm3. As a DR material, the three ceramics exhibit a resonant frequency signal each at 5.20; 5.21; and 5.22 GHz with the output power of -19.70; -14.47; -15.70 dBm, and the FWHM of the signal is 59.3; 61.6; and 61.2 MHz. Therefore, MZT04 ceramics can be applied as the DR material in microwave frequencies, especially at ~5.20 GHz. The variations in sinter holding time is not significant effect on the position of the resonant frequency.
Agus Solehudin, Enda Permana, Haipan Salam
SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 7; https://doi.org/10.21009/spektra.071.03

Abstract:
Research has been carried out to map and identify the potential for soil corrosion for the planning of cathodic gas pipeline protection systems. The research location is located in Cimanggis - Bitung, West Java, which is located at coordinates 6o19'00 "- 6o28'00" South Latitude and 106o43'00 "- 106o 55'30" East Longitude. Measurement of soil resistivity using the Wenner method that refers to ASTM G37, with variations in the distance of 0,75m, 1,50m, 2,50m and 6,00m with the number of measuring points as many as 185 points. Based on the results of data processing and soil resistivity interpretation seen that there are several locations that have low to extreme corrosion levels. Therefore, for these locations, technical planning and calculation for the protection of the pipeline to be installed is necessary.
Waode Sukmawati Arsyad, Ulpiani Ulpiani, Muh. Angga Anugerah, La Aba, Ida Usman
SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 7, pp 39-50; https://doi.org/10.21009/spektra.071.04

Abstract:
The objective of the study was to obtain the ZnO thin films with variation concentration of zinc acetate dehydrate (ZAD), and variation of spin coater speed and rotation time. We observed the effect of the former parameters on the optical characteristics that comprised of the spectrum of absorption, transmittance, and ZnO crystallite size from UV-Vis spectrometer and XRD orderly. For the analysis of the effect of the variation of concentration, ZAD diluted into ethanol with the concentration 0.1M, 0.25M, 0.5M, 0.75M dan 1M, with the addition of diethanolamine (DEA). Then it was deposited above the glass substrate with spin coater, continued by the heating on the hotplate with the number of layers variation. For the analysis of deposition parameter effect on the transmittance and the size of ZnO crystal, we used 0.25M ZnO precursor solution with the addition of DEA, then deposited by speed and time of rotation of spin coater of 1230 rpm, 2500 rpm, and 3200 rpm for 10, 15 and 30 seconds of each. The smallest absorbance value 0.05 obtained for single layer 0.1M ZnO, while the maximum transmittance value obtained for three-layer 0.25M ZnO. Concentration variation did not affect the energy gap, whose value was approximately 3.2 eV for all samples. From the XRD result, we found that deposition time affected the number of diffraction lines, the size of the crystallite, and the transmittance.
Widodo Kushartomo, Henny Wiyanto, Daniel Christianto
SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 6, pp 25-36; https://doi.org/10.21009/spektra.061.04

Abstract:
This research aims to make ultra high strength Reactive Powder Concrete (RPC) with marble powder as one of the components. The use of marble powder can increase Calcium Silicate Hydrate (CSH) and the strength of RPC. The research method used to achieve the objectives is experimental and divided into two steps. The first step is the characterization of a marble and micro silica powder mixture. Stoichiometry calculations are performed to determine the composition of the mixture. The test sample is made in the form of pellets consisting of a mixture of marble powder, micro silica, and water. The water content used is at 30% - 50%. Maintenance is carried out by immersion in water with the temperature of 20oC for 27 days and in steam at temperatures 200oC, 250oC, and 300oC with 2 atm pressure for 4 hours. Material characterization is carried out using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The second step in this research is the RPC compressive strength test. The test sample is made in the form of a cube measuring 50 x 50 x 50 mm. This cube is a mixture of water, cement, micro silica, marble powder, sand, and superplasticizer. Material composition is arranged based on the characterization of the sample pellet test, and maintenance of the sample cube test is carried out as in the sample pellet test.
Amalia Nasruroh, Bambang Sunardi, Muhammad Fikri Hayqal Hiola, Hendri Subakti
SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 6, pp 49-60; https://doi.org/10.21009/spektra.061.06

Abstract:
The devastating earthquake Mw 7.4 hit Palu City, Central Sulawesi on September 28th, 2018, at 17:02:44 WIB. A high tsunami followed it. More than 2000 people died as a result of the earthquake and tsunami disaster. The latest evidence shows that the earthquake was categorized as a rare super shear earthquake. The earthquake shaking that hit Palu City is relatively large. Acceleration data are not available at the study site due to the lack of instrumentation in the area. The Authors present a simulation of peak ground acceleration (PGA) and pseudo-spectral acceleration (PSA) due to the earthquake in three locations Tatura Mall, Roa-Roa Hotel, and Antapura Hospital. PGA describes the maximum acceleration on the ground, while pseudo-spectral acceleration describes the acceleration of earthquake shaking from buildings with various floor numbers. Simulation of PGA and PSA to the three sites used three different Ground Motion Prediction Equation (GMPE) functions, BSSA14, CB14, and CY14, with the weighting of each Next Generation Attenuation (NGA) GMPE functions. The results of PGA simulation is about 0.22-0.23 g and show that in the three study site, it is more vulnerable to spectral acceleration period T=0.3 s or building with three floors or about 1-15 floors. These correlate with the level of damage caused by earthquakes which is more impact to relatively higher buildings.
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