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Ali Khumaeni
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Department of Physics Faculty of Science and Mathematics Diponegoro University Jl Prof Soedharto SH, Tembalang, Semarang, Indonesia
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Journal of Physics and Its Applications
Published by Universitas Diponegoro
ISSN : -     EISSN : 26225956     DOI : 10.14710
Core Subject : Science,
Astronomy Earth & Planetary Sciences Materials Science & Nanotechnology Physics
Journal of Physics and Its Applications (JPA) (e-ISSN: 2622-5956) is open access, International peer-reviewed journal that publishes high-novelty and original research papers and review papers in the field of physics including Radiation Physics, Materials, Geophysics, Theoretical Physics, Instrumentation and Electronics, Medical Physics, Biomedical Physics, Chemical Physics, Mathematical Physics, and Applied Physics. The JPA publishes two issues annually (May and November). The journal is published by Department of Physics, Faculty of Science and Mathematics, Diponegoro University, Indonesia.
Arjuna Subject : Fisika dan Astronomi - Fisika dan Astronomi (Lain-Lain)
Articles 83 Documents
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Magnetic Susceptibility of Volcanic Rocks from Pahae Julu Region, North Sumatera Province Nurmala Dewi Siregar; Hamdi Rifai; Syafriani Syafriani; Ahmad Fauzi; Fatni Mufit
Journal of Physics and Its Applications Vol 4, No 2 (2022): May 2022
Publisher : Diponegoro University Semarang Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jpa.v4i2.13597

Abstract

Pahae Julu is a sub-district located in North Tapanuli Regency, North Sumatra. This area is often found with volcanic material from the eruption of Mount Toba (Youngest Toba Tuff). The Youngest Toba Tuff eruption occurred ~74,000 years ago with a volume of 2,800 km3. When there is an eruption, the lava on the earth's surface undergoes a relatively fast freezing process to form volcanic igneous rock. These rocks contain various minerals, one of which is magnetic minerals that can be used as a track record of volcanic processes from Mount Toba. However, no document records the magnetic susceptibility value of the Youngest Toba Tuff volcanic rock in the Pahae Julu area. This research aimsbfor knowing the abundance of magnetic minerals by the low-field magnetic susceptibility. To achieve this goal, the rock magnetism method is used. This way is very effective, cheap, sensitive, and non-destructive. Magnetic susceptibility measurements are done using the Bartington Magnetic Susceptibility Meter MS2B sensor. Rock samples analyzed are pumice which is the result of the Youngest Toba Tuff eruption. The results showed that the magnetic susceptibility value obtained for the sample was between 85.0 x 10-8m3/kg – 183.1 x 10-8m3/kg with an average of 119.78 x 10-8m3/kg. Based on this value, it is assumed that the magnetic mineral properties are Antiferromagnetic. The average value of χ fd% obtained is 0.95%, indicating that the Youngest Toba Tuff volcanic rock in the Pahae Julu area has almost no Superparamagnetic grains.
Effect of Yield Silver Nanoparticles in Enhancing Raman Signal of SERS Substrate Fabricated on Whatman Filter Paper Affi Nur Hidayah; Yuliati Herbani; Djoko Triyono; Rosari Saleh
Journal of Physics and Its Applications Vol 4, No 2 (2022): May 2022
Publisher : Diponegoro University Semarang Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jpa.v4i2.13226

Abstract

On Whatman Filter Paper, Surface Enhanced Raman Scattering (SERS) Substrate was created from colloidal silver nanoparticles by drop casting in varied volume colloidal nanoparticles of 3 ml and 6 ml. Using Raman Spectroscopy, SERS substrates were investigated for their ability to enhance 500 ppm of Deltamethrin pesticides Raman Signal. The number of colloidal nanoparticles is related to the volume of colloidal nanoparticles, indicating that high yields nanoparticle synthesis. The results demonstrate that fabricating SERS substrates in 6 ml increased Raman signal more than fabricating nanoparticles in 3 ml.
Analysis of Porous Silicon Formation on N-type Si (100) using Laser-Assisted Electrochemical Anodization Method Risa Suryana; Nabila Qurrota Aini
Journal of Physics and Its Applications Vol 4, No 2 (2022): May 2022
Publisher : Diponegoro University Semarang Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jpa.v4i2.12664

Abstract

Porous silicon (PSi) was formed on n-type Si (100) substrates using the laser-assisted electrochemical anodization method. The silicon surface was anodized in the solution of HF (40%) and ethanol (99%) in a ratio of 3:1 at a current density of 20 mA/cm2 for 15 min. The laser was illuminated on a silicon surface during the etching process. PSi surface morphology was characterized by SEM and identification of chemical bonds using FTIR. The highest number of pores, the best pore size homogeneity, and the smallest pore diameter in PSi were formed in Si which was illuminated by a green laser (2.33 eV). In contrast to red (1.91 eV) and purple (3.06 eV) formed irregular pores because of their small number and inhomogeneous size. On the PSi surface, Si-H and Si-O-Si bonds are formed. The number of Si-Hn and Si-O-Si bonds is directly proportional to the number of pores formed in PSi.
Depicting the Underground River Systems in Karst Mountains of Buayan and Ayah Subdistricts Using GGMPlus Data and Springs Distribution Agung Wibawa; Siti Fauzatun
Journal of Physics and Its Applications Vol 5, No 1 (2022): November 2022
Publisher : Diponegoro University Semarang Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jpa.v5i1.13210

Abstract

The karst mountain area in Buayan and Ayah subdistricts is a mountainous area that stretches from North to South and ends in the South coast region. In this area, many springs are found which are a source of clean water for residents. The existence of springs in the area is an indicator of the existence of underground rivers flowing under the mountainous area, this is also reinforced by the presence of interconnected caves and the existence of river flows in these caves. Analysis the presence of underground river flows in the Karst mountain area in the study area can be identified by looking at the type of rock formations that dominate the area. The density contrast shown through the residual gravity data also shows changes in rock formations related to the presence of water sources in the study area. GGMPlus data was obtained from forward modeling in order to get a residual map. This study shows that rock formations in the Karst area in the study area conform to the topographical shape.
Determination of Pediatric Patient Companion Dose at Thoracic X-Ray Examination Ega Duandini; Eko Hidayanto; Wahyu Setia Budi
Journal of Physics and Its Applications Vol 5, No 1 (2022): November 2022
Publisher : Diponegoro University Semarang Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jpa.v5i1.14011

Abstract

Thorax radiography examination in pediatric patients is one of the most frequent examinations because of many abnormalities that occur in the thorax and have a high probability at children's age. Pediatric patients are assisted by a companion from the adult patient's family. Calculation and measurement of the radiation dose received by the companion are very important as they are in the examination room with the patient during the imaging process. And no matter how small the radiation dose received by the companion, there will be an opportunity for stochastic effect. The Indonesian Nuclear Energy Regulatory Agency regulation Number 4 of the Year 2020 on Radiation Safety in the Use of X-Ray Machines in Diagnostic and Interventional Radiology, regulates the dose received by patient companions must be less than 5 mSv. This study aims to analyze the relationship between the exposure factor and the radiation dose received by the patient's companion. The TLDs used to measure the radiation dose was placed on the companion's chest. The radiation dose was calculated using the Klein-Nishina formula. The results show that the dose received by the companion ranged from 0.39 × 10-5 mSv to 4.64 × 10-5 mSv, which is much lower than the permissible dose.
Characterization of The Optical Properties of Motor Vehicle Engine Lubricants Using the Light Polarization Method Qidir Maulana Binu Soesanto; Ketut Sofjan Firdausi; Winarno Winarno; Wawa Gravelia Permana Prabawa
Journal of Physics and Its Applications Vol 5, No 1 (2022): November 2022
Publisher : Diponegoro University Semarang Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jpa.v5i1.14345

Abstract

This paper has carried out active and non-linear optical characterizations of motor vehicle lubricants. The samples used were three two-wheeled vehicle oil with SAE labels: 10W-40, 20W-50, and 10W-30 without pre-treatment. The active optical property (natural polarization) was measured as a function of the polarizer angle without external field interference. Meanwhile, non-linear optical properties (electro-optical polarization) used changes in the polarization of light as a function of the potential difference imposed on the sample. The light sources used were a green pointer laser (532 nm) and a red pointer laser (632 nm). The results showed that the oil has active and non-linear optical properties. The natural polarization characteristic produces two polarization peaks at 30° and 60° on both wavelengths and holds to all samples. It indicates that the dimensions and shape of the molecules in all samples are identical. It is also shown by electro-optical polarization, where the change in polarization acts as a quadratic function of the potential difference with the concentric curves of the three samples, indicating identical molecules. With electro-optical polarization, the total polarization is enhanced without changing the active optical properties in the sample. It gives an advantage for developing this method as a tracer and evaluator of the molecules of other relevant materials.
Assessment of Measured and Calculated Dose Rate of Co-60 Teletherapy Machine: 06 Years’ Experience at NORIN Nawabshah, Pakistan Muhammad Waqar; Touqir Ahmad Afridi; Quratulain Soomro; Muhammad Shahban
Journal of Physics and Its Applications Vol 5, No 1 (2022): November 2022
Publisher : Diponegoro University Semarang Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jpa.v5i1.15355

Abstract

It is essential to determine the absolute output dose of Co-60 source in the radiation treatment periodically. It is because overdosage may cause radiation hazards whereas under dosage may lead to the unsatisfactory treatment of cancer. The current study is focused on the consistency of monthly dose output verification of the cobalt-60 Teletherapy unit which should be within ±2% as per international standards. In the present study, the measured and calculated dose rate of the Co-60 teletherapy unit at Nuclear Medicine Oncology and Radiotherapy Institute Nawabshah (NORIN) for the last 6 years is analyzed. The dose measurement was done in water phantom 30×30×30 cm3 at 80 cm Source to Surface Distance with 5cm depth by using calibrated electrometer and PTW ionization chamber. The measured output dose rate obtained by actual dosimetry is within ±2% of the dose rate calculated by the decay method and the deviation lies within the permissible limit as prescribed by International Atomic Energy Agency (IAEA), International Commission on Radiological Units and Measurement (ICRUM)and American Association of Physicists in Medicine (AAPM). The variation in measurements obtained is within the tolerable limits according to standard protocols and codes. Thus, our study shows a homogenous trend in the dose rate of the Co-60 teletherapy machine.
Stokes' Law Approach to Slag Formation Process to Increase the Effectiveness of Cleaning Metal Liquids in Cast Iron Smelting Process Muhammad Rizki Gorbyandi Nadi; Cecep Ruskandi; Ari Siswanto; Gita Novian Hermana
Journal of Physics and Its Applications Vol 5, No 1 (2022): November 2022
Publisher : Diponegoro University Semarang Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jpa.v5i1.14502

Abstract

The purpose of this study was to increase the effectiveness of slag cleaning in the cast iron smelting process using an induction furnace. This study resulted in the calculation of the terminal velocity of the slag emerging to the surface of the induction furnace based on Stokes' Law approach for each slag that appears during the cast iron smelting process. For each cast iron casting, three samples were taken based on the fastest time on the very light slag, the slag’s time for the heaviest slag, and the extreme time for comparison. The results of each sample are tested for characterization such as shape, size, and chemical composition of each sample which are then adjusted to the calculations that have been made. The characterization was analyzed using X-ray diffraction, scanning electroscope, and energy dispersive spectroscopy microanalysis. The results show that the Stokes law approach to predict the slag reaching the surface gets the appropriate result that all the slag reaches the surface at time t = 230 s. The slag that appears at time t = 300 s is the slag formed due to the interaction of the liquid with the surface which is not the slag that occurs from the raw material used. This study succeeded in minimizing the formation of slag in each casting of cast iron using an induction furnace.
The Orbital Properties of Black Holes: Exploring the Relationship between Orbital Velocity and Distance Ruben Cornelius Siagian; Lulut Alfaris; Aldi Cahya Muhammad; Ukta Indra Nyuswantoro; Gendewa Tunas Rancak
Journal of Physics and Its Applications Vol 5, No 2 (2023): May 2023
Publisher : Diponegoro University Semarang Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jpa.v5i2.17860

Abstract

This research explores the concept of black holes in the physics of general relativity, including its formation and properties. The study focuses on the relationship between the orbital velocity and orbital distance of objects around a black hole, which is measured in units of the speed of light (c) and kiloparsecs (kpc), respectively. Using observational techniques, the study produces a plot showing the relationship between orbital velocity and orbital distance, which follows Kepler's law modified by the Newtonian theory of gravity and general relativity. The study also highlights the effective potential of particles in orbit around a black hole, which combines the effects of kinetic energy and gravitational potential. The effective potential shows the gravitational and relativistic properties of black holes, such as the photon orbit radius, ISCO, and the spin parameter. The resulting plot demonstrates the characteristics of the Milky Way black hole and how its spin parameter and Schwarzschild radius affect the orbital properties of surrounding particles. The study concludes that the closer the orbital distance is to the black hole, the more the orbital velocity increases, and particles with high spin parameters and small Schwarzschild radii are unlikely to escape the black hole's gravity.
Coupling Efficiency of a Spot Size Converter for Optical Fiber-Chip Connections Wildan Panji Tresna; Dedi Riana; Reza Rendian Septiawan
Journal of Physics and Its Applications Vol 5, No 2 (2023): May 2023
Publisher : Diponegoro University Semarang Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jpa.v5i2.17980

Abstract

The light propagation in optical waveguide must be able to maintain low propagation loss, low coupling loss and scattering loss condition, especially in the junction. In this research, a spot size converter is proposed to preserve the lowest coupling loss. This optical converter is composed of a single mode optical fiber (SiO2) including inversed taper. The optical input signal from the optical fiber is launched into photonic integrated circuits and then coupled into the Si-Slab waveguide. Furthermore, linear form with the length dependence has been studied to obtain the optimal position of optical fiber and the chip and analyzed the coupling efficiency of it. The purpose of this research is to procure the optimal form of spot size converter. The simulation result shows the coupling loss of linear form is 0.62 dB and 0.24 dB on TE and TM mode condition respectively. Along with the increase in the taper length, the coupling loss obtained tends to decrease as well. So that, it can be assumed the design of a linear form with 100 μm taper length provides the highest coupling efficie ncy.

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