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Spektra: Jurnal Fisika dan Aplikasinya

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Published by Universitas Negeri Jakarta

ISSN : 25413384 EISSN : 25413392 DOI : -

Core Subject : Science, Engineering,

Aerospace Engineering Electrical & Electronics Engineering Energy Materials Science & Nanotechnology Physics

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Articles 260 Documents

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A COMBINED METHOD OF 1D AND 2D RESISTIVITY FOR GROUNDWATER LAYER ESTIMATION AT A FARMING AREA IN REJOMULYO VILLAGE Antosia, Risky Martin; Ramdan, Muhammad
Spektra: Jurnal Fisika dan Aplikasinya Vol. 8 No. 1 (2023): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 8 Issue 1, April 2023
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.081.04

The groundwater depends on when it is available, more in the rainy and less in the dry seasons. Fluctuation in water availability is a significant problem in activities continuously requiring large amounts of water, such as agriculture. Hence, it is necessary to increase the number of water resources to meet the community's needs. Therefore, the groundwater layer zone was estimated as an initial study at the dry farmland in Rejomulyo village, Jati Agung district, South Lampung, using a combined method between the 1D resistivity method of the Schlumberger array and the 2D form of the Wenner configuration. Each sounding point and the 2D line have a maximum stretch length of 300 m. The 1D outcome correlates to the 2D data processing result to produce a subsurface lithology model. As a result, the research area has three primary layers with three rock types. The first layer has a resistivity value of less than 20 Ωm and is identified as tuffaceous clay. Then the second layer with a resistivity range of 60–66 Ωm is tuffaceous sand, this rock which is referred to as the groundwater layer with a depth of 11-40 m. The last layer has a high resistivity value of 120–141 Ωm as tuff. Based on the results of 3D visualization, the groundwater layer in the study area spreads to the southeast with a confined aquifer type. This targeted rock layer can be utilized for groundwater production.

FRONT MATTER SPEKTRA VOLUME 8 ISSUE 1, APRIL 2023 Spektra, Editor
Spektra: Jurnal Fisika dan Aplikasinya Vol. 8 No. 1 (2023): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 8 Issue 1, April 2023
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.08100

BACK MATTER SPEKTRA VOLUME 8 ISSUE 1, APRIL 2023 Spektra, Editor
Spektra: Jurnal Fisika dan Aplikasinya Vol. 8 No. 1 (2023): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 8 Issue 1, April 2023
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.081111

THE COMPARISON OF 2D DOSE PATIENT-SPECIFIC QUALITY ASSURANCE BETWEEN MONTE CARLO-CONVOLUTION AND MODIFIED CLARKSON INTEGRATION ALGORITHM Azzi, Akbar; Pawiro, Supriyanto Ardjo; Mart, Terry
Spektra: Jurnal Fisika dan Aplikasinya Vol. 8 No. 2 (2023): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 8 Issue 2, August 2023
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.082.01

A sophisticated machine of radiotherapy treatment process follows the complexity of the quality assurance (QA) measurement. Non-measurement QA becomes one of the solutions to reduce the medical physicists’ workload. However, this method has not been clinically established. This study compared two non-measurement methods of patient-specific quality assurance (PSQA) to find the feasible algorithm for the adaptive radiotherapy process. Monte Carlo-based (MC) PSQA used a phase space file of the medical linear accelerator (Linac) to obtain the photon energy fluence and forward projected to the isoplane. In contrast, Modified Clarkson Integration-based (MCI) used a non-uniform fluence map in the isoplane. For the modulated intensity, we used a pair of the dynamic log files of the multileaf-collimator (MLC) and then employed them in the algorithms. The dose distributions of MC and MCI methods were compared to the treatment planning system (TPS) using gamma index analysis. We found that the gamma pass rates (GPR) for MC-TPS and MCI-TPS were 99.54% and 99.57%, respectively. Further, the dose distribution in the off-axis region for the MCI method showed lesser accuracy due to the higher secondary dose contribution. The linac log file information can be used and calculated into a 2D dose distribution using both MC and MCI methods, providing high-accuracy results.

SYNTHESIZE OF TiO2 NANOPARTICLES BY PLANETARY BALL MILL FOR DYE-SENSITIZED SOLAR CELLS (DSSC) PHOTOELECTRODE APPLICATION Nurlaela, Ai; Yuniarti, Elvan; Saptari, Siti Ahmiatri
Spektra: Jurnal Fisika dan Aplikasinya Vol. 8 No. 2 (2023): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 8 Issue 2, August 2023
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.082.02

In this study, the production of TiO2 nanoparticles from microcrystalline powder was accomplished using the high-energy ball milling (HEBM) technique. Three samples were milled for 0.5, 1, and 1.5 hours. The unmilled powder was also characterized as a comparison. The X-ray diffraction (XRD) technique was utilized to investigate the changes in the microstructure of the milled powders over time. The XRD curve of milled samples showed the broadening of the diffraction peaks, which indicates a decrease in particle size after the milling process. Using the Debye–Scherrer relation, obtain the particle size that decreased from 138.43 nm before milled to 76.65 nm after 0.5 hours milled, 90.63 nm after 1 hour milled, and 83.05 nm after 1.5 hours milled. XRD analysis also showed that TiO2 was in an anatase phase before and after milling. Furthermore, two samples of TiO2, unmilled and after 0.5 hours milled, were used as a working photoelectrode of DSSC with dye from mustard leaves. DSSC efficiency was measured with a 1000-watt halogen lamp. The efficiency of DSSC with photoelectrodes using TiO2 after 0.5 hours milled, which is 0.1715, was higher than using TiO2 before milled, which is 0,0987. The Large surface area in TiO2 enhances the efficiency of DSSC, indicating that the HEBM technique is quite suitable for producing these nanoparticles for this aim.

EXPERIMENTAL AND COMPUTATIONAL STUDY OF NITROGEN-DOPED TiO2 AS A PHOTOELECTRODE Saptari, Sitti Ahmiatri; Yuniarti, Elvan; Loua, Lamin Rene
Spektra: Jurnal Fisika dan Aplikasinya Vol. 8 No. 2 (2023): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 8 Issue 2, August 2023
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.082.03

TiO2 has been widely used as a dye-sensitized solar cell (DSSC) photoelectrode, and attempts have been made to improve the performance of the photoelectrode by adding doping. This study aims to synthesize nitrogen (N) doped TiO2 as a photoelectrode. The research was carried out experimentally and computationally using X-Ray Diffraction (XRD) test equipment, Fourier Transform Infra-Red (FTIR), and quantum espresso software using the Density Functional Theory (DFT) method. XRD results showed that TiO2 has an anatase phase, and variations in the addition of nitrogen (doped N) of 10% w/w, 20% w/w, and 30% w/w did not produce a phase change. The FTIR results of N-doped TiO2 and TiO2 provide information on the functional groups of the samples. The wave number absorption area 1626 cm-1 indicates the presence of N-H bonds with a bending vibration mode. In addition, it can be seen that there is an N-H bond with a stretching vibration mode at wave number 3436 cm-1. Computational calculations searched the band gap energy of each variation of N doping, and each obtained was 3.2 eV; 2.54 eV; 2.35 eV; and 1.64 eV. The results of this study indicate that the N-doped TiO2 photoelectrode is expected to produce better DSSC efficiency because the addition of N-doped to TiO2 causes a decrease in the bandgap energy. The N doping effect causes a new energy level. The new energy level must be positioned close to the existing valence and conduction bands. As a result, the energy required for electrons to transition from the valence band to the conduction band is reduced, effectively reducing the energy gap between the two. This change in electronic structure facilitates more effortless movement of electrons, driving increased conductivity.

INVESTIGATION OF SUBSURFACE GROUNDWATER USING THE VES METHOD AROUND DENDAM LAKE, BENGKULU CITY, INDONESIA Maghribi, Faritz Bagda; Refrizon, Refrizon; Suhendra, Suhendra; Fadli, Darmawan Ikhlas; Halauddin; Idris, Beni Syakban; Johan, Henny; Putriani, Eli
Spektra: Jurnal Fisika dan Aplikasinya Vol. 8 No. 2 (2023): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 8 Issue 2, August 2023
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.082.04

Concerns have been raised over the availability of water in the Dendam Lake neighborhood of Bengkulu City and the areas surrounding it. The location is characterized by a number of unsuccessful water wells. These issues are the direct and indirect results of the geological formations that are present in the region, specifically Aluvium (which consists of boulders, clasts, sand, silt, mud, and clay). A MAE X-612 EM resistivity meter was utilized in order to get a total of twenty Vertical Electric Sounding (VES) measurement points. Using the software programs Progress and Surfer, the data that was gathered was plotted on a two-log graph. The geoelectric layer and layer parameter maps that were made were prepared with the use of quantitative and qualitative interpretations. It was determined that there were between three and five geoelectric layers. It has been demonstrated that the resistivity of the subsurface shallow groundwater zone ranges from 10 to 20 Ωm at a depth of 4 to 15 meters. According to the findings of this research project, employing the VES geo-electrical exploration approach is likely capable of effectively outlining the subsurface and shallow groundwater. In addition, there is no information available regarding the precise depth of the groundwater table in the region. On the other hand, the underground groundwater at this location has a depth that is shallower than the norm.

IDENTIFICATION OF PHYSICAL OCEANOGRAPHIC PARAMETERS AND MIXING TYPES AT THE TRANSITIONAL SEASON I IN THE ESTUARY OF AIR MANNA REGENCY SOUTH BENGKULU Supiyati, Supiyati; Sari, Devi Permata; Ekawita, Riska; Johan, Septi; Sudirman, Sudirman
Spektra: Jurnal Fisika dan Aplikasinya Vol. 8 No. 2 (2023): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 8 Issue 2, August 2023
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.082.05

The recent increase in community activity in the Air Manna Estuary of the South Bengkulu regency, will affect the physical condition of the estuary. Therefore, this research were to determine of the physical oceanographic parameters such as temperature, salinity, current velocity, tidal and the mixing type in the Air Manna estuary, South Bengkulu Regency at the transitional season I. The method used is the measurement of field data directly during high tide and low tide conditions as well as descriptive and quantitative data analysis. The results showed that the characteristics of the physical oceanographic pharameters in the Air Manna Estuary were influenced by tidal condition. The highest current speed at the mouth of the estuary is 2.6 m/s at low tide and 2.2 m/s at high tide, with the highest temperature in the upstream estuary of 27.49oC towards the sea during high tide conditions. The low salinity in the middle of the estuary of 0.99 ppt increases towards the sea with a relatively smaller distribution of salinity at low tide.The mixing type in the Air Manna Estuary is the Salt wedge estuary which has a well-certified mixing pattern, with an estuary number of 0.00019.

FRONT MATTER SPEKTRA VOLUME 8 ISSUE 2, AUGUST 2023 Spektra, Editor
Spektra: Jurnal Fisika dan Aplikasinya Vol. 8 No. 2 (2023): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 8 Issue 2, August 2023
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.08200

BACK MATTER SPEKTRA VOLUME 8 ISSUE 2, AUGUST 2023 Spektra, Editor
Spektra: Jurnal Fisika dan Aplikasinya Vol. 8 No. 2 (2023): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 8 Issue 2, August 2023
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.082111

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