Spektra: Jurnal Fisika dan Aplikasinya
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THE DESIGN OF DISPLAY DIGITAL DATA INTERFACE CLAMP-METER COMPLEMENTED BY SENSOR GMR (GIANT MAGNETORESISTANCE)
Get PDFThis article discusses the design of a robust data interface system that displays an electric current using the GMR sensor. Robust measurement of electrical current to detect magnetic fields contained in the current-carrying wire. The magnetic field on the cable should be the input signal to the GMR sensor to be processed by the interface program. This interface used the Arduino IDE program and displayed in the LCD screen. This research is an experimental research laboratory. The results of the data interface can be displayed in the form of comparative measurements with the power of the conventional electric current. Comparison measurements can be viewed in graphical form. The results of the study have an average measurement accuracy of 91.2%, with an average of 0.96. Besides, this study also obtained a standard deviation of 0.21 and an average error of 0:08
ANALYSIS OF THE EFFECT OF CARE DOSE 4D SOFTWARE USE ON IMAGE QUALITY AND RADIATION DOSE ON THE CT SCAN ABDOMEN
Get PDFThe CT Scan is the most significant contributor to radiation dose on radiological examination, although the frequency of the examination is far below other modalities. In order to control this radiation dose, manufactures of CT Scan have equipped their units with built-in software called Automatic Exposure Control (AEC). This study aims to analyze the effect of AEC software, CARE Dose 4D, on image quality, and CTDIvol. Objects used in this study were three water phantoms, each with a diameter of 165 mm, 230 mm, and 305 mm. The image quality-analyzed was CT Number and noise. Measurement of image quality was carried out following Bapeten's provisions. Noise Power Spectrum (NPS) graphics were also used to further observes noise texture. The CT Number accuracy, CT Number, and noise uniformity obtained with and without CARE Dose 4D, on the three phantoms were still within Bapeten's threshold. This indicates that the use of CARE Dose 4D can still image a homogeneous object accurately. The results of the NPS curve showed that the two modes, in three phantoms, were having the same noise texture. The NPS curves also showed that the use of CARE Dose 4D produces higher noise than the non-CARE Dose 4D mode. Meanwhile, there were significant differences from the CTDIvol obtained from the two modes. The use of CARE Dose 4D software reduced dose of up to 54.34%. From this, the use of CARE Dose 4D software can reduce the radiation dose while maintaining image quality
THE MONITORING SYSTEM OF INDOOR AIR QUALITY BASED ON INTERNET OF THINGS
Get PDFThe indoor air quality monitoring system is needed to find out good air condition. Good air condition can be seen from two (2) factors, namely dust, and temperature. Dust in a room can affect health if it exceeds the threshold of 0.15 mg/m3, and the temperature of 35oC has been determined by SK MENKLH No.02/MENKLH/I/1998. Related to that, we need a system that can determine the temperature and dust conditions in a room. The aim of this research is creating an indoor air quality monitoring system based on the Internet of Things (IoT). This research uses engineering methods, which include planning, design, testing, and system implementation. In this system, when the dust level is more than 0.15 mg/m3 the LED indicator 1 and the active sprayer tell and neutralize the dust content in the air and when the intensity of the temperature is more than 35oC the LED indicator 2 and the active sprayer tell and neutralize the temperature intensity at the room. When both values exceed the set threshold, the LED indicators 1, LED 2, buzzer, the sprayer will be active simultaneously to notify and neutralize the air and temperature in the room. The test results show this system can work well with the percentage of errors in the testing of 12% for dust sensors and 1.6% for temperature sensors
THE STABILITY STUDIES OF MIXED HALIDE PEROVSKITE CH3NH3PbBrXI3-X THIN FILMS IN AMBIENT WITH AIR HUMIDITY 70% USING UV-VIS SPECTROSCOPY AND X-RAY DIFFRACTION
Get PDFPerovskite Solar Cells (PSC), with the efficiency of more than 22%, has shown promising prospects for the future of environmentally friendly technology. However, low stability on humidity is a major problem limiting the commercialization of PSC. The perovskite material commonly used as a perovskite solar-cell active material is methylammonium lead tri-iodide (CH3NH3PbI3 or MAPbI3) prepared with a mixture of methylammonium-iodide (MAI) and lead iodide (PbI2). Perovskite material MAPbI3 is hygroscopic and easily decomposed into its constituent material, thereby reducing the performance of the PSC. Meanwhile, perovskite methylammonium lead-bromide (MAPbBr3) has higher moisture stability than MAPbI3 because it has a cubic crystal structure that has high symmetry. However, the efficiency of solar cells using MAPbBr3 as active material is lower than that of MAPbI3, due to a higher bandgap (~2.2 eV) than that of MAPbI3 (~1.5 eV). Therefore the wavelength range of sunlight absorbed by MAPbBr3 is shorter. We have studied the effect of the ratio of Bromium ion (Br-) insertion into MAPbI3 perovskite, forming mixed perovskite halide MAPbBrxI3-x on the stability of thin perovskite films in ambient with air humidity 70%. The value of x is varied from x = 0, 0.25, 0.5, 0.75 and 3. We measured the evolution of UV-Vis spectra and XRD patterns of thin perovskite films. The MAPbBr3 perovskite film is the most stable in high air relative humidity (> 70%). While mixed perovskite films with x = 0.5 are more stable as compared to the other x values based on absorption spectra. The XRD results showed that the stability of mixed halide perovskite is decreased with the increasing of x value
THE DETERMINATION OF BARIUM STRONTIUM TITANATE THIN FILM BAND GAP ENERGY Ba0,15Sr0,85TiO3 USING ULTRAVIOLET-VISIBLE SPECTROSCOPY
Get PDFA thin layer of Barium Strontium Titanate Ba0.15Sr0.85TiO3 (BST) was developed on a glass substrate using a sol-gel method with annealing temperatures and spin coating process at 3500 rpm for 30 seconds. The annealing temperature varied from 600oC, 650oC, and 700oC. Characterization of optical properties was developed using UV-Vis spectroscopy to determine the energy bandgap. The values of the BST thin layer energy band at the annealing temperature were 3.55 eV, 3.32 eV, and 3.10 eV, respectively. The results indicate that the BST thin film was a semiconductor material
THE CHANGE OF ROCK CONDITION OBSERVED BY H/V SPECTRAL AND ELLIPTICITY CURVE INVERSION ANALYSIS (CASE STUDY: PALU EARTHQUAKE SEPTEMBER 28, 2018)
Get PDFPalu City is composed of sedimentary rocks so that it has a high level of vulnerability when an earthquake occurs. The earthquake that occurred on September 28, 2018, 25 km north of Donggala with a magnitude of 7.4 Mw, had caused a tsunami that struck Palu City, Sigi Regency, Donggala Regency, and Parigi Mouthong Regency, Central Sulawesi Province. This earthquake also caused liquefactions in the Petobo and Balaroa areas, Palu City, and Jono Oge in Sigi Regency. In this study, the authors used microtremor data at 8 points measured before and after the earthquake. Processing using the Horizontal to Vertical Spectra Ratio method shows that the predominant frequency and amplification factor changes due to changes in local rock conditions. The analysis also shows the value of soil vulnerability index (Kg) mostly increased after the earthquake. Besides, the elliptic curve inversion method shows that before the earthquake event, the value of the S wave velocity (Vs30) in layer one was between 157.1-211.4 m/sec with a layer thickness between 65.3-90.6 meters, while after the earthquake, the velocity becomes 156-214.6 m/sec with a layer thickness ranging between 66-99.2 meters. This indicates that the area consists of soft and medium soils, which subsequently increased sediment thickness in most areas after the earthquake
DESIGN OF NEUTRONIC PARAMETERS OF MTR REACTOR USING WIMSD-5B/BATAN-FUEL CODES
Get PDFBATAN has three aging research reactors, so it is necessary to design a new, more modern MTR type reactor using high-density, low enrichment uranium molybdenum fuel. The thermal neutron flux at the irradiation position is an important concern in the design of research reactors. This analysis is performed using standard computer codes WIMSD-5B and Batan-FUEL. The purpose of this study is to analyze the effect of the core configuration with safety control rods and neutronic parameters using the diffusion method calculation. The reactor core consists of 16 fuel elements and four control rods placed in the 5 x 5 position of the grid plate and is loaded the reflector elements outside the core. The cycle length is also a concern, not less than 20 days, and the reactor can be operated safely with a power of 50 MW. The calculation results show that for the highest fuel loading, which is 450 grams of U7Mo/Al fuel with D2O as a reflector, it will provide the lowest thermal neutron flux at the center of the core irradiation position, namely 1.0 x1015 n/cm2s. The core fuel cycle length will be up to 39 days, meeting the expected acceptance and safety criteria
DESIGN OF THE POLLUTION GAS CARBON MONOXIDE (CO) MONITORING SYSTEM BASED ON MICROCONTROLLER
Get PDFCarbon monoxide is a flammable gas and very toxic to humans, to determine the concentration of carbon monoxide (CO) gas requires a tool that can measure the concentration of the gas. The design of the CO gas monitoring measuring instrument in this study has dimensions of 11cm x 8.6 cm x 2.9 cm using the MQ-135 sensor, Arduino Uno microcontroller to control and process the signal, to display temperature and humidity with a 4.2 Inch LCD. Krisbow KD09-224 Carbon Monoxide Meter is a comparison tool or calibrator, against our monitoring gauges. Testing by experimenting as much as 15 times, to determine the value of the measurement uncertainty. Based on the results of the data when testing, the average amount of measurement = 103.33, with a standard deviation δ 1.29, and the uncertainty value of the measurement results is 0,33 %. Thus the system can be used as monitoring of CO gas pollution in units of ppm (parts per million)
ANALYSIS AND INTERPRETATION OF TIME-LAPSE MICORGRAVITY DATA CASE STUDY IN KOTA LAMA SEMARANG TOURISM AREA
Get PDFA time-lapse microgravity survey has been carried out in the Kota Lama (Semarang, Indonesia) tourism area. The survey in question is to measure gravity at the same point repeatedly with a specific time interval, in this case, conducted in January 2019 and July 2019. Measuring gravity is carried out at as many as 75 points that are spread evenly at the survey location. The instrument used is a Scintrex CG5 type gravimeter and GPS to determine the latitude and the longitude of each measuring point. The measurement results after being corrected, namely the Apungan and the Appeal correction, obtained the observational gravity (gob) in the January 2019 period showing that a minimum of 978118.44 mGal and a maximum gravity of 978118.88 mGal, while the minimum gravity measurement value in July 2019 showed a minimum of 978118.62 mGal and a maximum of 978118.88 mGal. Changes in the value (anomaly) gravity during the time interval, there are two possibilities, positive (0.02 to 0.29 mGal) and negative (-0.11 to -0.01 mGal). Both of these anomaly prices, if they are modeled, an anomaly source will be obtained, which is a positive anomaly caused by subsidence and a negative caused by changes in subsurface density related to dynamics (decrease or increase) of groundwater level