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Journal : EINSTEIN (E-JOURNAL)

INVESTIGATION OF DOMINANT FREQUENCY AND GROUND AMPLIFICATION BASED ON HVSR MICROTREMOR METHOD IN PANGURURUAN DISTRICT, SAMOSIR Nasution, Nazaruddin; Sirait, Ratni
EINSTEIN (e-Journal) Vol. 12 No. 3 (2024): EINSTEIN (e-Journal)
Publisher : Universitas Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24114/ein.v12i3.57360

Abstract

In this study, microtremor wave measurements were carried out using the HVSR (Horizontal to Vertical Spectral Ratio) method to identify earthquake vulnerability in Pangururuan District, Samosir, North Sumatra. In this study, measurements were made at 4 points scattered around the area so that the data obtained represented data in the area. Measurement of signal recording data was carried out for 50-60 minutes for each measurement point. Based on the results obtained, the dominant frequency value of the soil is in the range of 2.29 - 12.78 with a very high classification at points RGR1, RGR3 and RGR4 with type I soil classification, namely hard rock, and point RGR2 is classified as low with type IV soil classification, namely soft soil. While the amplification value in Pangururan District is still classified as a low amplification category with an amplification value of <3.
MICROTREMOR ANALYSIS IN DETERMINING LANDSLIDE POTENTIAL IN SEMBAHE VILLAGE, SIBOLANGIT DISTRICT, DELI SERDANG REGENCY Lubis, Rahmadhani; Sirait, Ratni; Lubis, Lailatul Husna
EINSTEIN (e-Journal) Vol. 12 No. 3 (2024): EINSTEIN (e-Journal)
Publisher : Universitas Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24114/ein.v12i3.60753

Abstract

Sembahe Village is an area that is highly vulnerable to landslides. This is caused by steep topographic conditions and high rainfall. This research is intended to understand the characteristics and distribution of dominant frequencies, amplification factors and seismic vulnerability index on the possibility of landslides. Microtremor measurements were carried out in Hamlet 3 Sembahe Village at 2 location points which were measured using a portable seismograph / Pegasus for 2 hours with a sampling frequency. 100 Hz. Microtremor data was processed using Geopsy software using the Horizontal to Vertical Spectral Ratio (HVSR) method and each parameter was weighted using the Analytical Hierarchy Process (AHP) statistical method in determining potential landslide areas. The results obtained show that the distribution of dominant frequency values (F0) is 5.36 Hz – 5.33 Hz, amplification (A0) is 1.84 – 1.59, seismic vulnerability index (Kg) is 0.63 x 10-3s2 / cm - 0.47 x 10-3 s2/cm. Based on weight analysis using the AHP statistical method, the location point that has the highest potential for landslides is point 1
CALCULATION OF ELECTRONIC PROPERTIES OF LiBX3 (B = Pb AND Sn; X = Br, Cl AND I) CUBIC PHASE BY DENSITY FUNCTIONAL THEORY Sagala, Junaina Sahputri; Sirait, Ratni; Ong, Russell
EINSTEIN (e-Journal) Vol. 12 No. 3 (2024): EINSTEIN (e-Journal)
Publisher : Universitas Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24114/ein.v12i3.61583

Abstract

Perovskite solar cells utilize perovskite as the active material to convert sunlight into electrical energy. Perovskite is a compound with a crystal structure of ABX₃, where A and B are cations, and X is an anion, usually a halide. Research continues to find perovskites with high efficiency. This efficiency is related to the electronic structure, which can be analyzed using Density Functional Theory (DFT). In this study, the electronic structure of cubic phase LiBX₃ perovskites (B = Pb and Sn; X = Br, Cl, and I) is investigated using Quantum ESPRESSO software. Various parameters such as cut-off energy, k-points, and lattice constants were modified to obtain optimal values. From the optimization results, the band gap, DOS, and PDOS values for the six perovskites were obtained. The resulting band gap energy (Eg) are LiPbBr₃ at 1,71 eV, LiPbCl₃ at 1,87 eV, LiPbI₃ at 1,43 eV, LiSnBr₃ at 0,51 eV, LiSnCl₃ at 0,65 eV, and LiSnI₃ at 0,28 eV. These results show that the band gap energy values increase with the change in atomic radius from Sn to Pb and decrease with the change in atomic radius from Cl, Br to I. The electronic structure calculations of LiBX₃ (B = Pb and Sn; X = Br, Cl, and I) show semiconductor properties that have the potential to be used as light-absorbing materials in perovskite solar cells. This study states that LiBX₃ has great potential in solar cell applications and offers a deep understanding of the relationship between crystal structure and its electronic properties.