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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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Rainfall Classification Analysis Using Naïve Bayes Classifier Based on Air And Wind Temperatures in Serang City Abdilah, Meilani Nisa; Ruhiat, Yayat; Guntara, Yudi
Spektra: Jurnal Fisika dan Aplikasinya Vol. 9 No. 1 (2024): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 9 Issue 1, April 2024
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.091.04

The city of Serang experiences relatively high annual rainfall, with an average total of more than 100 mm/year. Based on data obtained from BMKG, Serang City, in 2023, there will be a shift in the rainy season due to weather anomalies, affecting the amount of rainfall. Apart from that, Serang City is one of the cities with less rain throughout September, recorded within 15 days. In this case, a determination is needed in the form of rainfall classification. However, an exemplary method is required in order to classify rainfall so that the classification results are accurate. Several studies showed that the naïve Bayes classifier method is the best classification method compared to other analysis methods; namely, it only requires a probability. The parameters used are air temperature and wind speed. So, this research aims to determine the classification of rainfall using the Naïve Bayes classifier based on air temperature and wind in Serang City. The method used is non-experimental quantitative with naïve Bayes classifier analysis. Based on the data analysis using Microsoft Excel software, the results showed that in the Serang city area, February 2024 was classified as a humid month with rainfall of 100 - 200 mm, and March 2024 was classified as a dry month with rainfall <100 mm.

Impacts of Gorkha Earthquakes: A Comprehensive Study Adhikari, Pitri; Nepal, Shanta; Dawadi, Sapana
Spektra: Jurnal Fisika dan Aplikasinya Vol. 9 No. 1 (2024): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 9 Issue 1, April 2024
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.091.05

Nepal is highly vulnerable to seismic activity. This review seeks to explore the impact of earthquakes on human populations in terms of casualties and injuries, as well as to pinpoint the risk factors associated with these outcomes. An earthquake measuring 7.8 on the Richter scale struck near Gorkha, Nepal, on April 25, 2015, resulting in the loss of nearly nine thousand lives, extensive property damage, and the destruction of numerous historical and cultural landmarks. Data sourced from the UNDRR, Ministry of Home Affairs, and the United States Geological Survey were analyzed using the ArcGIS software tool. The study offers a comprehensive examination of earthquake-prone regions at regional, national, and global levels. By analyzing recent significant earthquakes along with their associated losses and damages, it underscores the importance of precautionary measures and risk analysis in reducing vulnerability and enhancing preparedness among researchers and stakeholders.

Pair Correlation Influence on Superconductors Josephson Penetration Depth Poudel, Yadhav; Gupta, Suresh Prasad; Shrestha, Narayan Babu; Yadav, Kishori; Dhobi, Saddam Husain
Spektra: Jurnal Fisika dan Aplikasinya Vol. 9 No. 1 (2024): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 9 Issue 1, April 2024
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.091.02

The Josephson penetration depth is an essential characteristic of Josephson junctions, serving a role akin to the London penetration depth in bulk superconductors. It originates from the substantial self-magnetic field generated by a strong Josephson supercurrent, influencing the distribution of the gauge invariant phase difference across the junction. This study delves into the intricate relationship between cooper pair correlation and critical temperature in superconductors. To study relationships authors develop theoretical method and observed that critical temperature exhibits a noteworthy decrease with an increase in cooper pair correlation. Specifically, as the level of coherence among electron pairs rises, the material's capacity to maintain the superconducting state at elevated temperatures is enhanced, resulting in an elevated critical temperature. Conversely, regions characterized by lower pair correlation demonstrate a sharp reduction in critical temperature, indicating their heightened susceptibility to changes in correlation levels. This sensitivity is particularly pronounced across junction and penetration depth where cooper pair correlation is diminished. Furthermore, the study reveals an exponential decay trend in critical temperature concerning cooper pair correlation, underscoring the pivotal role played by pair correlation in the superconducting state. Even slight alterations in pair correlation have a substantial impact on the material's ability to exhibit superconductivity. These findings provide valuable insights for the tailored design and optimization of superconducting materials for specific applications. By leveraging the understanding gained from this research, it becomes possible to engineer materials with enhanced superconducting properties. This study not only advances our fundamental comprehension of superconductivity but also offers practical implications for a diverse range of technological applications.

Synthesis Process and Nutritional Evaluation of Plantain as a Supplementary Food for Toddlers in Sierra Leone: A Study Utilizing Biuret’s, Benedict’s, and Iodine Solution Test Koroma, Lahai; Senesie, James Kuiva; Baion, Florence Wuyah; Lukulay, Baindu Miata; Kallon, Massah Badiwuloi
Spektra: Jurnal Fisika dan Aplikasinya Vol. 9 No. 2 (2024): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 9 Issue 2, August 2024
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.092.04

Research on developing plantain fruit into juice, jam, ice cream, and fritters as a food supplement for toddlers was conducted in Sierra Leone. The work was done at the Mosoudo section of Daru village, Jawie Chiefdom, in Kailahun District. Four bunches of plantains were harvested from Jawei Chiefdom and stored in Mosoudo. Two bundles of the raw plantain were peeled, dried, and ground into powder, while the other two left to ripen at room temperature for nine days. Test were conducted using Iodine solution, Benedict solution, and Biuret test to check the presence of starch, glucose, and protein, respectively, in both the powdered and ripe plantain. The ripe plantains were then made into juice, jam, ice cream, and fritters. Fifty mothers/caregivers, along with their children, were randomly selected to evaluate the color, taste, smell, and texture of the four plantain products. The sensory evaluation results showed high acceptance levels: color (53.5%), taste (59.0%), smell (61%) and texture (59.9%). The results suggest that the project could successfully provide nutritious and appealing food supplements for toddlers in Sierra Leone. It was recommended that the government and NGOs promote the cultivation of plantains instead of importing food supplements for children in Sierra Leone.

Front Matter SPEKTRA Volume 9 Issue 1, April 2024 Spektra, Editor
Spektra: Jurnal Fisika dan Aplikasinya Vol. 9 No. 1 (2024): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 9 Issue 1, April 2024
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.09100

Back Matter SPEKTRA Volume 9 Issue 1, April 2024 Spektra, Editor
Spektra: Jurnal Fisika dan Aplikasinya Vol. 9 No. 1 (2024): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 9 Issue 1, April 2024
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.091111

Enhanced Approaches to Gravitational Lensing: A Regular Charged Black Hole in Weak Field Limit Din, H. M. U.; Ramadhan, H. S.
Spektra: Jurnal Fisika dan Aplikasinya Vol. 9 No. 2 (2024): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 9 Issue 2, August 2024
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.092.03

Gravitational lensing, an integral aspect of general relativity, profoundly impacts our understanding of black holes (BH’s). The presence of a centered singularity resulting from gravitational collapse is a fundamental characteristic of a BH. Nonetheless, the exploitation of non-linear electrodynamics (NLED) divulges the emphatic concept of non-singularity. Our analysis primarily focuses on calculating the deflection angle in the weak field approximation, deliberately excluding the original spacetime configuration. The photon’s effective geometry is typically linked to NLED. Instead, a photon traverses an effective null geodesic that aligns with the geometry of a regular metric. The findings reveal an additional term in the deflection angle compared to the Reissner-Nordström (RN) metric, evidenced by a shifted positional displacement of the tertiary image associated with a regular BH. This study succinctly encapsulates these findings, positioning them within the extensive terminology ambient to BH’s singularity and GL, thus edifying the scientific memoir with precise astrophysical insights.

Gravitational Lensing for A Spherically Symmetric Regular Charged Black Hole in Weak Field Limit Shidik, M. F.; Ramadhan, H.
Spektra: Jurnal Fisika dan Aplikasinya Vol. 9 No. 2 (2024): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 9 Issue 2, August 2024
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.092.05

Gravitational lensing is an integral part of the study of general relativity, as it is one of the direct consequences of general relativity. The existence of singularity within the black hole due to gravitational collapse is one of the key properties of the black hole. However, the introduction of non-linear electrodynamics (NLED) offers an intriguing possibility: nonsingular black holes. This work focuses on calculating the deflection angle within the weak field limit. Here, the photon's effective geometry associated with NLED is not incorporated; instead, the regular metric is utilized as it is, without presupposing its origins in NLED. A correction term in the deflection angle to the Reissner-Nordstrom (RN) case was found. This term manifests as a displacement in the position of the third image associated with the black hole.

Exploring Weak Gravitational Lensing Effects by a Regular Black Hole Durrani, A. K.; Ramadhan, H. S.
Spektra: Jurnal Fisika dan Aplikasinya Vol. 9 No. 2 (2024): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 9 Issue 2, August 2024
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.092.02

Gravitational lensing is one of the physical consequences of Einstein’s general theory of relativity, which has been observationally confirmed. This work aims to study the weak gravitational lensing scenario where the lens is a spherically symmetric, charged-nonsingular black hole that asymptotically behaves as the Reissner-Nordström (RN). The difference exists in the higher-order expansion. Therefore, the metric function of the regular charged black hole is expanded up to the fourth order, and the deflection angle is calculated. The thin lens equation is used, leading to five images: two imaginary and three real images. The exact positions of the images and magnification properties are calculated by providing the physical parameters such as mass, charge, and distances. Our calculation shows that the third image position shifted away from the optical axis. The formalism is applied to the case of a supermassive black hole located at the center of our galaxy with the assumption that it has an electric charge.

Front Matter SPEKTRA Volume 9 Issue 2, August 2024 Spektra, Editor
Spektra: Jurnal Fisika dan Aplikasinya Vol 9 No 2 (2024): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 9 Issue 2, August 2024
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.09200

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