JURNAL ILMU FISIKA

Development of River Flow and Water Quality Using IOT-based Smart Buoys Environment Monitoring System

2023-09-22T22:18:04+07:00

Efficient and accurate river water quality monitoring is needed to support laboratory testing based on on-site sampling. Therefore, we have developed a monitoring system for river flow and water quality using sensor-equipped buoys and the Internet of Things (IoT) concept. An ESP32 NodeMCU microcontroller integrated with WiFi and compatible with Arduino IDE is used in the system. The buoy is equipped with GPS to determine the position and flow speed and sensors to measure water quality parameters of pH and temperature. Data on position, flow velocity, and water quality parameters are transmitted over a WiFi network using the MQTT protocol. The data is recorded by the buoy and uploaded and displayed on the adafruit.io platform. Positioning was done by comparing the values displayed on the Neo-6M GPS with the Maps application on the smartphone. The results show that the GPS coordinate values are accurate. The water quality parameter values obtained have an error rate of 3.3% for the pH sensor and 1.02% for the temperature sensor. Thus, the system we have developed has the potential to be used as a substitute for field sampling-based river water quality monitoring systems.

Particle Size Improvement and Layer Absorption of Metil Halida MAPbI3 Perovskite Doping Phenethylammonium Iodide (PEAI)

2023-09-15T23:46:52+07:00

This study aims to determine the effect of phenethylammonium iodide (PEAI) doping on grain size and absorption of the methylammonium lead iodide (MAPbI₃) perovskite layer. The MAPbI₃ perovskite layer is interesting to study because of its potential application in perovskite solar cells. In this study, the preparation of MAPbI₃ perovskite layer with PEAI doping variation using a 2-step spin-coating method. The surface morphology of MAPbI₃ shows an increase in grain size with the addition of PEAI doping variation. The optimum grain size is shown by adding 1.0 mg/ml PEAI doping variation, which is 117 ± 1.19 nm with a smooth surface morphology and tends to be homogeneous. X-ray diffraction (XRD) results on Perovskite MAPbI₃ showed no difference in peaks with the addition of PEAI doping. However, there is only a slight angle shift of 2 theta, 0.05° at the main peak (110) and (220), so it will not change the cubic structure of MAPbI₃ crystal. The ultra violet visible (UV-Vis) graph shows an increase in absorbance of Perovskite MAPbI₃ with the addition of PEAI doping in the wavelength range of 400-550 nm. This research is expected to be a foundation for developing more efficient and stable solar cells.

Efficiency at Maximum Power of Endoreversible Quantum Otto Engine with Partial Thermalization in 3D Harmonic Potential

2023-09-22T22:18:29+07:00

We study the partial thermalization to the effect of efficiency at maximum power (EMP) of a quantum Otto engine using Bose-Einstein Condensation in 3D harmonic potential. Partial thermalization occurs at a finite-time isochoric process, preventing the medium from achieving equilibrium with reservoirs, leaving it in a state of residual coherence. Under these circumstances, the performance of the engine can be seen from its power and EMP. The 3D harmonic potential is used to generate an excitation of energy during the expansion and compression. The total energy is defined by the total work done in a cycle. Using Fourier’s law in conduction, we found that power explicitly depends on the duration of heating and cooling stroke time and efficiency of the engine; that is the higher stroke time and efficiency, the less power output. In order to find EMP, we maximize power with respect to compression ratio κ, and we found that EMP also depends on the isochoric heating and cooling process. By varying the stroke time of the isochoric process, EMP slightly decreases with increasing isochoric time due to entropy production. However, adjusting cooling stroke time more extended than heating stroke time could significantly improve the EMP of Otto Engine.

The Impact of Radiation Dose Variation in Panoramic Dental Examination on Salivary Amylase Enzyme Activity

2023-09-08T13:07:51+07:00

The surge in oral and dental diseases has amplified the significance of dental panoramic imaging as a diagnostic tool for healthcare professionals. However, such imaging subjects patients to radiation, impacting salivary pH and amylase enzyme activity. This study of 30 patients aimed to measure radiation doses and their effects on salivary pH and amylase enzyme activity. Radiation doses were quantified using a Thermoluminescent Dosimeter (TLD-100) and analyzed with a TLD reader. Salivary pH was determined using a digital pH meter, and amylase enzyme activity was assessed through the iodine method, involving a reaction between a 1% amylum solution, iodine solution, and saliva. Results showed an average radiation dose of 2.33 μSv, significantly affecting salivary pH. Specifically, 28 patients experienced an average pH decrease of 0.34, while 2 had an average pH increase of 0.385. These pH changes corresponded with variations in amylase enzyme activity. In 17 patients, amylase activity increased by an average of 0.75×10^-4 units/mL, while 13 patients exhibited an average decrease of 0.96×10^-4 units/mL. This underscores the intricate relationship between radiation dose, salivary pH, and amylase enzyme activity, warranting further exploration within dental panoramic imaging.

Quality Control Analysis of Linear Accelerator Radiotherapy Device in the Department of Radiotherapy at Pasar Minggu District Hospital

2023-06-23T21:39:28+07:00

Radiation accidents pose a significant risk, often stemming from inadequate calibration of radiation output, procedural lapses, and faults in radiation monitoring systems. Addressing these risks is pivotal, particularly in radiotherapy, where the precise functioning of linear accelerator (Linac) devices is crucial. This study delves into the quality control procedures applied to the Linac radiotherapy device within the Department of Radiotherapy at Pasar Minggu District Hospital. Drawing upon the renowned reference standards set by the AAPM Task Group 142 and BAPETEN Regulation No. K2N.2/MT-08, this research, conducted in November 2022, rigorously evaluated the mechanical, dosimetry, and safety aspects of the Linac device. The examination encompassed critical elements, including gantry angles, optical distance indicators, laser precision, collimator angles, light field size, and photon and electron beam outputs. Safety features such as door interlocks, audiovisual indicators, and radiation alert systems were scrutinized. The analysis reveals a reassuring finding: the Linac device at Pasar Minggu District Hospital adheres commendably to tolerance limits specified by reference standards across all measured parameters, indicating robust performance in mechanics, dosimetry, and safety. This meticulous quality control regimen has proven highly effective in ensuring the device's operational integrity and safety, affirming its reliability for precise radiotherapy treatments.

The Accuracy of TIAC Calculated Using SPECT/CT Imaging Data at 36- and 100-Hours Post Injection and Prior Information in 177Lu-DOTATATE

2023-08-22T11:13:41+07:00

In internal radionuclide therapy, there is a growing demand for streamlined methods that alleviate the measurement burden on patients and reduce the associated costs of individual dosimetry. This study assessed the precision of the Two Time Point Dosimetry (2TPD) model, a data-efficient approach, compared to the well-established All Time Point Dosimetry (ATPD) model. The investigation involved the analysis of time-activity data collected from the kidneys of seven patients who were administered ¹⁷⁷Lu-DOTATATE and underwent SPECT/CT imaging (PMID 3344306). Data points were specifically gathered at the 36-hour and 100-hour post-injection marks. Employing prior information, a monoexponential function was applied to fit the biokinetic data. Consequently, two crucial metrics, TIAC ATPD and TIAC 2TPD, were computed for ATPD and 2TPD, respectively. To provide a benchmark, the TIAC determined via the Hänscheid method was also incorporated for comparison. The comparative analysis revealed that the percentage error between the population ATPD model and the 2TPD model was (3.97 ± 7.85)%, and for the Hänscheid model, it was (1.8 ± 7.9)%. These findings affirm that the accuracy of TIAC values derived from the 2TPD approach, leveraging prior-information fitting, is reasonably satisfactory.

Analysis of Secondary Particles Produced by 50-500 MeV Muon and Water Interaction using PHITS Monte Carlo Package

2023-12-16T15:33:56+07:00

Secondary particles will always be generated in particle-to-matter interactions. The interaction of muons with matter produces various secondary particles. In this study, secondary particles produced by the interaction between muons with energies of 5, 50, 100, 200 and 500 MeV with water were analyzed using the PHITS Monte Carlo package. The muon source is placed on the surface of water that has a thickness of 1 km. The muography technique was applied by placed a detector at a depth of 1 km from the source. This detector records the secondary particles produced by the interaction. The results obtained show that this interaction produces secondary particles in the form of photons and neutrons in the detector. The number and energy of these photons and neutrons are strongly influenced by the initial energy of the muon. Muons with the lowest energy of 5 MeV produce more secondary particles than any other energy by a factor of 10. Low-energy muons travel slowly, allowing more interactions to occur and increasing the number of secondary particles in the detector. The energies of neutrons and photons in the detector are at most 3.76 MeV and 5.3 MeV, respectively.

Study of The Effect of Calcination Temperature on the Phase Composition of ZnO Powder Synthesized via The Sol-Gel Method

2024-01-04T17:50:40+07:00

This study investigated the effect of calcination temperature on the phase composition and crystal size of zinc oxide powders synthesised by the sol-gel method. Zn powder, HCl and NaOH were used as precursors in a multi-step process involving dissolution, titration, gel formation, leaching, drying and calcination at temperatures ranging from 300°C to 700°C for 2 hours. Rietveld analysis of X-ray diffraction (XRD) data using MAUD and Rietica software determined phase composition and crystal size. Initial analysis identified a single simonkolleite phase (Zn5(OH)8Cl2) prior to calcination, which disappeared at 500°C. Wurtzite (ZnO) appeared at 300°C, accompanied by secondary phases (NaCl and ZnCl2). The wurtzite content increased to 81.42 wt% at 700°C. Calcination temperature also influenced crystal size, which ranged from 27.34 nm to 110.61 nm for wurtzite at different temperatures. The results highlight the dynamic changes in phase composition and crystal size with different calcination temperatures, providing valuable insights into tailoring zinc oxide properties for various applications.

Increased Hardness Value of Medium Manganese Steel Through Double Tempering, Hot Rolling, and Variation of Cooling Media

2024-01-21T13:25:05+07:00

Research has been conducted to enhance the hardness value of medium manganese steel through a heat treatment. Initially, this process begins with austenization at a temperature of 900°C, followed by tempering at 650°C and double tempering at 600°C, with each stage lasting 30 minutes. Subsequently, each stage concludes with a hot rolling process, after which air or water cools the material. As a result of these processes, the hardness tests revealed an increase in the hardness of medium manganese steel, reaching up to 389.70 BHN with a tensile strength of 827 MPa, which was notably achieved through air cooling. This significant increase in hardness is attributed to the emergence of the martensite phase and the presence of a large number of carbides, which are more evenly distributed after the double-tempering process. Additionally, small amounts of carbides were observed in the austenite matrix. Upon examination of the SEM fractography results, it was revealed that the fracture was mixed, with a cleavage area slightly larger than the dimple area. This observation suggests that despite its high hardness value, the sample retains good toughness.

The Synthesized-Hydroxyapatite Powder from Anadara Granosa Shells using Deposition Time Method for Biomedical Applications

2024-02-06T08:30:18+07:00

Hydroxyapatite (HAp) powder, one of the biomaterials derived from natural sources, could be used in biomedical applications. In this research, the synthesized-HAp powder from Anadara Granosa shells as raw materials had a high calcium carbonate content with variations in deposition time using the precipitation method. Variations of deposition time used were 0 (S0), 24 (S24), and 48 (S48) hours. Fourier Transform Infrared (FTIR), X-Ray Diffractions (XRD), and Scanning Electron Microscopy (SEM) were used to investigate the chemical structure, phase analysis, and morphology of the synthesized HAp powder. FTIR results of the S0, S24, and S48 showed that the functional groups , and were formed at variations in the deposition time. The XRD results showed that the smallest of crystallite size of S48 was 26.03 nm, and the crystallinity degree of S24 was 38.74%. The grain dispersity of the synthesized-hydroxyapatite powder from SEM results were uniform, agglomeration, and spherical, irregular shape. The Ca, P, Mg, and Si compositions were shown in the synthesized-hydroxyapatite powder. The deposition time affects the synthesized-Hydroxyapatite (HAp) powder from the Anadara Granosa shell, and it is a potential raw material for biomedical applications.