Jurnal Penelitian Fisika dan Aplikasinya (JPFA)

Analysis of the Concept of Force Balance in the Atag Warehouse, Jember Regency

2023-05-30T14:57:17+07:00

Physics learning is rarely associated with the local wisdom of the local community, so most people assume that the two topics are very different. This article analyzes the concept of force balance in the Atag warehouse building in Jember Regency. This study used qualitative research using content analysis techniques in which there is unitizing, sampling, coding, reducing, inferring, and narrating. Data were collected through field observations, literature studies, interviews, and documentation. The research indicates that the Atag warehouse building has several parts, namely doors, windows (tabing lambung), columns (rooms), warehouse roofs, and foundations. In the Atag warehouse, there is the concept of static balance, namely the equilibrium of rigid objects found in the frame, rope ties, foundation, semat, and Atag warehouse doors. Then there is the concept of a heavy point found in the bottom cover and the center of the Atag shed. Furthermore, there is the concept of dynamic balance, namely the moment of force that can be found in the warehouse window and the moment of inertia in the bamboo part whose bonds loosen when stepped on by warehouse workers. Integrating Atag warehouses in learning activities can make it easier for students to understand physics concepts. This article concludes that the Atag warehouse has a static and dynamic balance that can be used as physics learning material and can also help preserve regional culture.

Cold Surge Effect on Vertical Profile Atmosphere over Meteorological Station of Ranai Natuna: Case Study Asian Winter Monsoon 2019/2020

2023-05-20T09:25:42+07:00

During the Asian Winter season, which spans from November to February, the phenomenon of cold surge often occurs, leading to increased convective activity over the western Indonesian Maritime Continent. The location of Natuna Island, situated in the southern part of the South China Sea, is of particular importance for studying cold surges due to their propagation over this area. In this study, the vertical structure of the atmosphere was analyzed using radiosonde observation data collected at the Meteorological Station of Ranai Natuna. The analysis focused on physical parameters such as air temperature and relative humidity, atmospheric kinematics including wind direction and speed, as well as atmospheric thermodynamic parameters such as Lifting Condensation Level (LCL), Level of Free Convection (LFC), Equilibrium Level (EL), Convective Available Potential Energy (CAPE), and Convective Inhibition (CIN). The results indicate that during the passage of a cold surge, air temperature (T) tends to be higher in the lower troposphere, including at the surface, but lower in the middle and upper troposphere. Relative humidity (RH) also tends to be higher during cold surges, with a significant increase in the middle and upper troposphere. In the lower troposphere, the wind direction shifts from east to northeast at a higher speed compared to when a cold surge is absent. Furthermore, the LCL and LFC heights are elevated during the presence of a cold surge, while the EL height shows an insignificant decrease. It is worth noting that intense rainfall occurs, particularly when the cold surge is more pronounced, even though the values of CAPE and CIN do not change significantly.

Exploring Reservoir Potential of the "X Field" Offshore, Niger Delta Basin: An Emphasis on Lithofacies, Depositional Environments, and Petrophysical Characteristics

2023-05-19T21:16:41+07:00

The geological circumstances under which sediments are built throughout time are referred to as depositional environments. The features of the sediment, such as its texture, composition, and permeability, are influenced by these depositional environments, and these qualities ultimately define the reservoir quality. This study focuses on identifying reservoirs in the western offshore region of Nigeria's Niger Delta Basin and evaluating their properties, such as lithofacies, distribution, and petrophysical characteristics like porosity and permeability, using well log analysis. By utilizing relevant and easily accessible well log data, the depositional environment and quality of the reservoir were evaluated. The data analysis involved examining gamma-ray log patterns, spontaneous potential, deep resistivity, neutron, and density. The thickness of the reservoirs varies between 15 and 440 meters, with thicker reservoirs likely being composite structures formed from layered channels. Sands deposited in high-energy settings have higher levels of porosity and permeability. Sands C and D are the most porous and permeable sand units in the field, while the remaining sands have medium permeability. Hydrocarbons are present in sands B, C, D, and E in varying fluid types and column diameters. The reservoir sands C, D, and E have high hydrocarbon saturation and low water saturation, indicating that more oil than water will be produced. On the other hand, irreducible sand B suggests that more water than oil will be produced. Reservoir sands B, C, and D contain only water and oil. This information can aid in locating production platforms and optimizing hydrocarbon recovery, as well as improving reservoir performance estimates. The geological and petrophysical data collected in this study can also guide the analysis of other fields similar to the "X Field" in Nigeria's Niger Delta offshore region.

Identification of COVID-19 Based on Features Texture Histogram and Gray Level Co-Occurrence Matrix (GLCM) Using K-Means Clustering Methods in Chest X-Ray Digital Images

2023-05-21T21:44:15+07:00

Since the last five years of the COVID-19 outbreak, radiological images, such as CT-Scan and Chest X-Ray (CXR), have become essential in diagnosing this disease. However, limited access to facilities such as CT-Scanners and RT-PCR makes CXR images the primary method for COVID-19 testing. This research aims to improve the accuracy of CXR images in identifying COVID-19 patients based on the texture features: histogram and Gray Level Co-occurrence Matrix (GLCM), using the K-Means Clustering method. This study utilized 150 CXR images, including 75 COVID-19 patients confirmed by RT-PCR tests, and 75 patients with negative cases. The method used were consisted of pre-processing, and texture feature extraction with the seven most influential attributes based on gained information (histogram: standard deviation, entropy, skewness, kurtosis, and GLCM: correlation, energy, homogeneity), as well as classification using K-Means clustering methods. The results showed that the classification’s accuracy, sensitivity, and specification are 92%, 91%, and 93%, respectively. This image processing technique is a promising as well as a complementary tool in diagnosing COVID-19 cases, based on CXR images with lower costs and more reliable results.

Structural and Optical Properties of Bismuth-doped Cerium Oxide Prepared at a Low Temperature

2023-05-05T14:22:26+07:00

Cerium oxide (CeO₂) is a functional material with excellent physicochemical properties. Its properties can be modified by doping with different elements, including bismuth, which can be done through various synthesis methods. The precipitation method combined with ultrasonic radiation was used to synthesize bismuth-doped cerium oxide (CeO₂:Bi) at a low temperature of 200^oC. In this study, we investigate the alteration of structural and optical properties of as-prepared CeO₂:Bi by subjecting it to additional calcination at a high temperature of 500^oC. The structural and optical properties of CeO₂:Bi were characterized using thermal gravimetric analysis, X-ray diffraction, Scanning Electron Microscope-Energy Dispersive X-Ray, Fourier Transform Infrared spectroscopy, and UV-Visible spectroscopy. The additional calcination produced a less significant weight-loss percentage than the as-prepared CeO₂:Bi observed from the gravimetric curve. The Fourier transform infrared spectrum revealed the loss of a small number of hydroxyl molecules trapped on the CeO₂:Bi surface when additional calcination was subjected. Based on the X-ray diffraction spectra, additional calcination results in the smallest crystallite size and compressive strain without the changed cubic crystal structure of CeO₂:Bi. The successful doping of Bi in CeO₂was confirmed by the composition analysis from Energy Dispersive X-Ray measurement. Scanning electron microscope image showed spherical and agglomerated particles of calcined CeO₂:Bi. The optical properties of both CeO₂:Bi possessed similar trend absorption spectra and almost the same band gap energy. The results indicated that the calcination of as-prepared CeO₂:Bi at a temperature of 500^oC did not affect its structural and optical properties significantly. Thus, combining ultrasonic radiation with precipitation is an advantageous method to synthesize at a low temperature of stable CeO₂:Bi crystalline.