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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 5 Documents
 1 
Search results for , issue "Vol 5, No 2 (2023): May 2023" : 5 Documents clear
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.
A method for quantification of noise non-uniformity in computed tomography images: A computational study Choirul Anam; Ariij Naufal; Kosuke Matsubara; Toshioh Fujibuchi; Geoff Dougherty
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.v5i2.17615

Abstract

In computed tomography (CT), the noise is sometimes non-uniform, i.e. the noise magnitude may vary with the gradient level within the image. The purpose of this study was to quantify the noise non-uniformity in CT images using appropriate 1D and 2D computational phantoms, and to validate the effectiveness of the proposed concept in images filtered by the bilateral filter (BF), as an example of a non-linear filter. We first developed 1D and 2D computational phantoms, and Gaussian noises with several noise levels were then added to the phantoms. In addition, to simulate the real form of noise from images obtained in a real CT scanner, a homogeneous water phantom image was used. These noise levels were referred to as ground truth noise (σG). The phantoms were then filtered by the bilateral filter with various pixel value spreads (σ) to produce non-uniform noise. The original gradient phantoms (G) were subtracted from both the noisy phantoms (IN) and the filtered noisy phantoms (IBF), and the magnitudes of the resulting noise for each gradient were computed. The noise-gradient dependency (NGD) curve was used to display the dependency of noise magnitude on image gradient in the non-uniform noise. It is found that for uniform noise, the magnitude of noise was constant for all gradients. However, for non-uniform noise, the measured noise was dependent on the gradient levels and on the strength of the BF for every ground truth noise (σG). It was found that the noise magnitude was large for the large gradients and decreased with the magnitude of the image gradient.
Terahertz Quasi-Time Domain Spectroscopy using a 808nm multimode diode laser Ivan Cedrick Malaluan Verona; Alexander De los Reyes; Hannah Bardolaza; Elmer Estacio
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.v5i2.17945

Abstract

We report on a terahertz quasi-time domain spectroscopy (QTDS) system based on a low-cost continuous wave multimode diode laser. Commercially available low-temperature grown gallium arsenide (LT-GaAs) based photoconductive antennas (PCAs) with spiral and dipole configurations were used as emitter and detector, respectively. Terahertz pulses spaced at approximately 55 ps with a bandwidth of 400 GHz were obtained. Parametric measurements of the terahertz peak-to-peak intensity were performed by varying the injection current and temperature while maintaining incident laser power. The highest peak-to-peak intensity was obtained at 170mA injection current and 20° C temperature settings. The change in the THz peak-to-peak intensity is attributed to the mode hopping characteristics of the device which in turn, is dependent on injection current and temperature.
Fluid Flow Regimes Analysis on Drilling Fluid Circulation for Cuttings Lifting in Vertical Drilling Oil Wells Isnani Agriandita; Ismanu Yudiantoro; Niken Ayoba NR
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.v5i2.17181

Abstract

Fluid Flow during the circulation of the drilling fluid is an important parameter that affects the process of successful lifting of cuttings during drilling activities. Researcher analyzed the regimes of the drilling fluid flow in vertical drilling wells through the analysis of the velocity calculation of the drilling fluid in the pipeline at conditions in the Drillpipe (v DP) of 21.11791 fps and in drill collar of (v DC) is 42.98293 fps, the velocity of drilling fluid in the annulus between the Casing and the Drill pipe is 1.14993 fps, 1.373781 fps between Open Hole and Drill pipe, and 1.594947 fps between Open Hole and Drill Collar, the critical velocity of drilling fluid in the pipeline and in the annulus, Reynolds number in the pipeline is 15986.36, inside Drill Collar of 22807.21, and in the annular between the Casing and the Drill pipe is 2847.435, between Open Hole and Drill pipe 3037.264, and 2679.938 between Open Hole and Drill Collar, and the velocity at which the drill cutting drops when in the annulus in all three zones is 0.14914 fps. The results of the analysis of fluid flow that occurs are found that in the pipe there is a turbulent flow and in the annulus a laminar flow occurs. In addition, the results of the analysis of the comparison between the velocity of the drilling fluid in the annulus and greater than the velocity of descent of the cuttings show that the cuttings can be lifted by the drilling fluid successfully. This indicates that the fluid lifting process is successful.

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