Jurnal Ilmu Fisika (JIF)
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Peninjauan Parameterisasi Wind Gust saat Kejadian Konvektif dan Non-Konvektif: Studi kasus di Bandara Internasional Kertajati
No full textWind gusts (gusts) are sudden increases in wind speed that potentially cause severe damage to infrastructure. Gusts occur within several seconds but numerical weather models typically predict future wind with a time step of tens of seconds or minutes. Therefore, a parameterization is needed to estimate gust. Gusts can be produced convectively and non-convectively depending on the presense of thunderstorm. The gust parameterization schemes may perform differently in both cases. In this study, five wind gust parameterization schemes were evaluated at the Kertajati International Airport. Based on simulations of three convective gust and three non-convective gust events using several evaluation metrics, we find that the best scheme for non-convectively driven gusts is the Turbulent Kinetic Energy (TKE) scheme, while the Hybrid scheme performs best for convectively driven gusts. However, the performance of Hybrid scheme during non-convective event is not so far behind TKE scheme. The Hybrid scheme was developed to work on both non-convective and convective events and this capability is evidently shown. The result could be useful to develop mitigation measures for strong wind incident that frequently occurs in Indonesia.Wind gust adalah angin yang menguat secara tiba-tiba yang dapat mengakibatkan kerusakan pada infrastruktur atau menghabat aktivitas offshore dan onshore sehingga wind gust perlu diprediksi. Gust terjadi dalam waktu beberapa detik namun model cuaca numerik biasanya simulasi dengan langkah waktu puluhan detik atau beberapa menit. Oleh karena itu, sebuah parameterisasi dibutuhkan untuk mengestimasi gust. Gust dapat diakibatkan oleh kejadian non-konvektif dan konvektif. Gust non-konvektif ialah gust yang muncul tanpa adanya awan badai. Dua tipe gust ini mungkin membutuhkan skema parameterisasi yang berbeda. Dalam studi ini, lima parameterisasi wind gust diuji di Bandara Internasional Kertajati. Berdasarkan simulasi pada tiga kejadian konvektif dan tiga kejadian non-konvektif, kami menemukan metode terbaik ialah skema Hybrid. Kami juga menemukan bahwa estimasi gust juga sensitif terhadap faktor lain seperti: variasi angin rata-rata, hujan, dan aktivitas konvektif. Studi ini ialah salah satu upaya untuk mengembangkan langkah mitigasi untuk kejadian angin kencang yang sering terjadi di Indonesia
Uncertainty in the Management of Tropical Peatlands for Oil Palm Plantations due to Drainage Practices
Full text linkThe conversion of tropical peatlands to oil palm plantations has affected the long-term storage stability of water and carbon. The conversion requires a drainage system that results in land subsidence and, in turn, reduces the carrying capacity of water storage and carbon stocks. This study aims to analyze subsidence from long-term observations (2004-2020) to obtain an appropriate water management measure for three scenarios of drainage depths at the oil palm plantations in Jambi Province. It is found that the reduction is quite variable depending on the level of drainage depths. The subsidence was 55 cm, 49 cm, and 34.7 cm for deep, moderate, and shallow drainage conditions. The groundwater level was deeper than 100 cm, which is far below the threshold of 40 cm, as stated in the government regulations. However, the regulations are still debated since subsidence must occur in drained peatlands regardless of the water level. The observed large subsidence implies that better water management in a new site is crucial and necessary to reduce the impact of peatlands degradation relative to current conditions and that high rates of land subsidence should be accepted as an inevitable change from the conversion of tropical peatlands to oil palm plantations
An Analysis of the Schrodinger Equation Model for the Distribution Rate of Stock Returns
Full text linkQuantum mechanics is a theory that describes the behavior of particles in the microscopic world. If the stock index can be considered an object on a macro scale, then every stock of a stock index is an object on a micro-scale. The stock price can be analogous to being a particle. This study aimed to obtain the density distribution of stock returns. Modeling stock returns distribution using a Schrodinger equation model with the assumption that stock is a particle in the good delta potential function so that stock returns as analogous to particles can be known. The Schrodinger equation can calculate stock returns expressed as an exponential distribution. The stock return density distribution using Schrodinger equation model has a higher kurtosis value than the kurtosis value in the normal distribution. The kurtosis value is the degree of the peak height of a distribution. The stock price data used is the stock price data of PT. United Tractors Tbk. and PT. Unilever Indonesia Tbk. during 2013-2018. This study shows the stock price of PT. Unilever Indonesia Tbk. has a more stable average stock price return with a more negligible risk of loss than the stock price of PT. United Tractors Tbk
Frequency and Amplification for Assessing site Effects and PVS in the Padang City Railway
Full text linkThe train uses a special line in the form of railroad tracks that produce vibrations during movement. This study aims to determine the type of soil layer and the peak particle velocity due to the train around the Padang City train line. The acquisition was carried out at 8 points with a recording duration of 65 minutes using three geophone components. Microtremor data was analyzed using horizontal to vertical spectral ratio (HVSR) method. The results show that the research area has a type of surface layer of soil is sediment with a thickness of 30 meters or more. This is indicated by the dominant frequency value ranging from 0.64 Hz – 1.67 Hz. The research area has an amplification value ranging from 0.85 to 1.29. The train vibration has a dominant frequency ranging from 2.20 Hz – 13.54 Hz and an amplification of 1.11 – 1.82. The particle velocity values obtained from the PVS values ranged from 0.1605 mm/s – 0.7592 mm/s. The research area can be categorized as safe from train vibrations because of the low amplification value and the PVS value which is below the safe limit (<3 mm/s) according to SNI 7571:2010
Utilization of LDPE Plastic Waste, Coconut Shell and Coconut Husk as Basic Material for Briquettes with Tapioca Starch Adhesive
No full textBio-briquettes of organic waste can be used as alternative energy to solve the waste problem. This study aimed to determine the quality of bio-briquettes made of LDPE, coconut husk, and coconut shell with tapioca adhesive. The coconut husk and shell were carbonized at 300 °C for 60 minutes. Charcoal that has been ground and sieved with 40 mesh is mixed with tapioca flour adhesive, and pieces of LDPE are added. Then, the sample is pressed with a cylindrical mold with a matrix strength of 5 tons. Bio-briquettes were dried in an oven at 80 °C for 12 hours. The quality of the briquette was evaluated through proximate analysis, including the calorific value, moisture content, ash content, volatile matter content, and fixed carbon content. The calorific value of all samples complied with the regulation of the Ministry of Energy and Mineral Resources (ESDM) No. 047 of 2006, which is above 4400 cal/g. The maximum moisture content is 15%, which fulfills SNI 06–3730-1995 standards, and the ESDM regulation, especially for the composition of 40% shell: 40% coconut: LDPE 20%. The ash content, volatile matter content, and fixed carbon content of all samples did not comply with SNI briquette standards and ESDM regulations
Relationship between Solar Flux and Sunspot Activity Using Several Regression Models
Full text linkThis study examines the correlation and prediction between sunspots and solar flux, two closely related factors associated with solar activity, covering the period from 2005 to 2022. The study utilizes a combination of linear regression analysis and the ARIMA prediction method to analyze the relationship between these factors and forecast their values. The analysis results reveal a significant positive correlation between sunspots and solar flux. Additionally, the ARIMA prediction method suggests that the SARIMA model can effectively forecast the values of both sunspots and solar flux for a 12-period timeframe. However, it is essential to note that this study solely focuses on correlation analysis and does not establish a causal relationship. Nonetheless, the findings contribute valuable insights into future variations in solar flux and sunspot numbers, thereby aiding scientists in comprehending and predicting solar activity's potential impact on Earth. The study recommends further research to explore additional factors that may influence the relationship between sunspots and solar flux, extend the research period to enhance the accuracy of solar activity predictions and investigate alternative prediction methods to improve the precision of forecasts
The Accuracy of TIAC Calculated Using SPECT/CT Imaging Data at 36- and 100-Hours Post Injection and Prior Information in 177Lu-DOTATATE
Full text linkIn 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
PENGEMBANGAN SISTEM MONITORING ALIRAN DAN KUALITAS AIR SUNGAI MENGGUNAKAN PELAMPUNG BERBASIS SMART ENVIRONMENT
No full textEfficient 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.Telah dilakukan pengembangan sistem monitoring aliran dan kualitas air sungai menggunakan pelampung yang dilengkapi sensor dan konsep Internet of Things (IoT. Mikrokontroller ESP32 NodeMCU yang terintegrasi dengan WiFi dan kompatibel dengan Arduino IDE digunakan dalam sistem. Pelampung dilengkapi dengan GPS untuk menentukan posisi dan kecepatan aliran, serta sensor untuk mengukur parameter kualitas air yang terdiri dari pH, dan suhu. Data posisi, kecepatan aliran dan parameter kualitas air dikirimkan melalui jaringan WiFi menggunakan protokol MQTT. Data direkam oleh pelampung dan diunggah dan ditampilkan platform adafruit.io. Posisi dilakukan dengan membandingkan nilai yang ditampilkan pada GPS Neo-6M dengan aplikasi Maps di smartphone. Hasilnya menunjukkan bahwa nilai koordinat GPS akurat. Nilai parameter kualitas air yang diperoleh memiliki tingkat kesalahan untuk sensor pH 3,3 % dan 1,02 % untuk sensor suhu
Quality Control Analysis of Linear Accelerator Radiotherapy Device in the Department of Radiotherapy at Pasar Minggu District Hospital
Full text linkRadiation 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 Impact of Radiation Dose Variation in Panoramic Dental Examination on Salivary Amylase Enzyme Activity
Full text linkThe 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