Spektra: Jurnal Fisika dan Aplikasinya
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254 research outputs found
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Phase Dynamics in 3D Superconductors: Analysis Using the Sine-Gordon
Full text linkThis study investigates the phase dynamics of superconducting states in 3D superconductors using the sine-Gordon equation, with a focus on the interplay between the London penetration depth (LPD) and coherence length ( ). The research employs a combination of analytical modeling and simulation techniques to explore how variations in LPD influence phase behavior across different coherence lengths in the developed model. At a critical coherence length of = 2 Å, the LPD decreases from 150 nm to 120 nm as the nanoparticle spacing increases from 5 nm to 10 nm, attributed to reduced interactions between superconducting states. Conversely, at = 1 Å, quantum confinement effects lead to non-linear LPD behavior, with an initial decrease from 180 nm to 160 nm followed by an increase to 200 nm as nanoparticle spacing changes. In 3D superconductors, phase evolution is characterized by distinct waveforms—square, rectangular, and mixed—corresponding to LPD values between 100 nm and 200 nm, with phase shifts ranging from 1° to 20°. Smaller phase shifts (1°) produce higher-frequency oscillations with amplitudes up to 0.2, while larger shifts (20°) generate broader, less intense waveforms. These findings underscore the critical role of LPD in determining superconducting properties, offering valuable insights for the design and optimization of superconducting devices to enhance performance and efficiency
The Effects of Stellar Wind, Rotation Velocity, and Overshoot Parameters on The Evolution of Massive Stars using MESA: Case Study of MPG 324, MPG 355, MPG 682
Full text linkMassive stars (over 8 solar masses) undergo intricate cosmic journeys. Their evolution, shaped by parameters like stellar wind, rotation velocity, and overshoot, generally includes the pre-main sequence, main sequence, and post-main sequence phases. In the post-main sequence, they become supergiant stars, then Wolf-Rayet stars, experience a supernova, and end as neutron stars or black holes. This study models the evolutionary path of massive stars using MESA software, considering stellar wind, rotation velocity, and overshoot. Three stars from the Small Magellanic Cloud galaxy—MPG 324, MPG 355, and MPG 682—are used to represent the mass range described in the Conti Scenario. The model is compared to Conti Scenario and observational data, showing good agreement with luminosity, effective temperature, and evolutionary phase, though not yet at final stages. This provides valuable insights into stellar evolution
Application of Variational Quantum Eigensolver for Ground State Energies Calculation in Hydrogen and Helium Atomic Sequences
Full text linkExponential scaling presents a significant challenge in electronic structure calculations performed on classical computers. This paper explores how quantum computer algorithms can accurately represent quantum systems. Variational Quantum Eigensolver (VQE) algorithm is used to compute the ground state energy of hydrogen and helium sequences by implementing variational principle and quantum gates as trial wavefunction. This technique combines classical optimization with quantum computing calculations to simulate quantum systems on noisy and resource-limited computers. The resulting calculated energy is highly consistent to the corresponding exact values and Hartree-Fock calculations with a trend of when the number of atoms increases the calculated energy becomes more negative, leading to a decrease in the percentage error. Moreover, the convergence of the ground state energy of hydrogen and helium atoms was effectively optimized. The desired energy was reached, proven by adjusting the expectation value, and gradually achieving unity in state overlap. These findings demonstrate the VQE method's accuracy in calculating simple quantum systems and its scalability for larger atomic and molecular system, such as those in quantum chemistry and material science. However, challenges in quantum computer simulations, such as limited in qubit numbers and the presence of noise, require further advancements. Therefore, implementing a larger basis sets, advanced qubit mapping, specific chemistry ansatz, and flexible optimization techniques is one way to improve overall calculation
Laser-Assisted Scattering with Screened Diatomic Potential
Full text linkThis study explores the differential cross section (DCS) for laser-assisted scattering of diatomic molecules, considering various polarization conditions (linear, circular, elliptical) and potential parameters. The primary objective is to understand how polarization, screening effects, and potential parameters influence the scattering behavior. Utilizing a model that incorporates the Morse potential with screening effects, the analysis treats the laser field classically as a time-dependent, spatially homogeneous electric field, while the electron dynamics are described quantum mechanically using the Schrödinger equation. The Volkov wavefunction is derived, and the first-Born S-matrix element is computed to evaluate the scattering process. The results show that the DCS decreases with increasing screening parameters, with linear polarization yielding higher values than circular or elliptical polarization. Specifically, at an initial momentum of 8 MeV and a final momentum of 9 MeV, the DCS for elliptical polarization is notably higher. The DCS also varies with potential strength and well width, showing a peak at 0.14 Å for potential well width. The findings suggest that linear polarization is most effective for scattering studies under varying potential strengths. It is recommended to focus on linear polarization for enhanced scattering efficiency and to carefully adjust screening parameters and potential well widths for optimal results
Development of a Real-Time Gas Concentration Measurement System Using Internet of Things-Based Monitoring
Full text linkTransportation and industrial activities have contributed to an increase in the concentration of pollutant gases such as CO, NO2, and SO2 in the air. High concentrations of these gases can adversely affect human health. One approach to addressing this issue is by measuring and monitoring gas concentrations in the air. The advancement of technology, specifically the Internet of Things (IoT), facilitates the monitoring process. Therefore, this research focuses on the development of a gas concentration measurement system, utilizing the MQ-7 sensor for CO, the MiCS-6814 sensor for NO2, and the MQ-136 sensor for SO2. Additionally, the system is integrated with a website as a platform for monitoring the sensor measurements. The research results indicate that the system has been successfully developed with relative errors of 0.286% for the MQ-7 sensor, 0.325% for the MiCS-6814 sensor, and 0.280% for the MQ-136 sensor. The system underwent testing at three different locations, conducting gas concentration measurements in the environment for 24 hours. The environmental testing revealed measured gas concentration ranges of 2.52-7.67 PPM for CO, 0.00450-0.103 PPM for NO2, and 0.0100-0.0652 PPM for SO2. The measurement data is accessible and observed in real-time through the website, presented in graphical form, indicating average concentration values of CO, NO2, and SO2 over a 3-hour period. Moreover, the website is equipped with indicator lights that serve as alarms if the environmental gas concentration exceeds predefined thresholds
Seismometer Health Diagnosis Based on Cross Spectral Density Coherence Method in Indonesia Seismic Networks
Full text linkEvaluation of seismometer health is crucial in accurately detecting earthquake and tsunami events. Currently, seismometer health evaluation is based solely on data quality unrelated to seismometer sensor performance. While seismometers are essential for tracking seismic activity, environmental factors, aging components, and external interference can cause seismometers to function worse over time. This study presents a seismometer health diagnosis technique based on seismic signal analysis, including signal truncation, signal resampling, filtering, and deconvolution of instrument response. Then the proposed method of cross-spectral density coherence to extract seismometer sensor health indicators performed on two adjacent broadband seismic stations by analyzing the frequency domain with a maximum inter-station distance of 100 km. The data used are seismic signals recorded on three-component seismometers (North-South, East-West, Z-Vertical). The coherence value of cross-spectral density is used as an indicator to diagnose seismometer health. The proposed method was evaluated on a seismic network in Indonesia consisting of 88 stations and a teleseismic earthquake event in Honshu, Japan. The coherence values of almost all tested stations are above 0.8, which means good performance. The proposed method is suitable for analyzing the health of seismometers, especially in Indonesia
Thickness Measurement and Sensitivity of Copper/Nickel Electroplating Results of Electrolyte Solution Temperature Variation
Full text linkCurrently, cryogenic thermometers are needed and one of the uses of cryogenic thermometers is to measure the temperature of food preservation flasks. Research has been conducted on the manufacture of cryogenic thermometers derived from Cu/Ni coils by electroplating process with temperature variation treatment of electrolyte solution. The purpose of this study is to determine the effect of electrolyte solution temperature variation treatment on Ni thickness and Cu/Ni sensitivity as a low-temperature sensor. Electroplating was carried out with electrolyte temperature parameters of 30˚C-70˚C, electrode distance of 4 cm, voltage of 4.5 volts, and coating time of 4 minutes. The electrolyte solution was a mixture of NiSO4 260 g, NiCl2 60 g, H3BO3 40 g, and Aquades 1000 mL. Based on the results of the study, a remarkable condition was obtained on the thickness of Ni; namely, at 40 ˚C, the thickness increased to 1.08 mm. In addition, the best temperature can produce the greatest sensitivity value in Cu/Ni coil electroplating, namely at 50 ˚C