Spektra: Jurnal Fisika dan Aplikasinya
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STUDY OF THE EFFECT OF MAGNETIC FIELDS ON ELECTROENCEPHALOGRAPHY MEASUREMENT IN FARADAY’S CAGE
Full text linkElectroencephalography (EEG) is a method for recording the brain's electrical activity through electrodes placed on the scalp's surface. The amplitude of the EEG signal is in the 40–100 V range, with the five main frequencies in the 0 to 100 Hz range. The EEG is non-stationary and very susceptible to various disturbances, especially frequency disturbances, so eliminating troubles in the raw EEG data is essential to obtain helpful information reflecting brain activity. Interference in the EEG signal comes from muscles, eye movement and blinking, power lines, and interference with other devices. The distractions overlap. Shielding is required to perform an EEG without the risk of interference and ambient background noise. This study tested how the influence of magnetic field disturbances on EEG measurements was carried out in the Faraday cage and an unprotected room. The magnetic field was measured before, during, and after the EEG was operated. EEG measurements were performed on subjects who were conditioned to rest for 5 minutes. The EEG signals generated when EEG recordings were performed in the Faraday and the unprotected rooms were compared. It was found that the difference in the value of the magnetic field originating from electronic devices around the subject does not significantly affect the EEG measurement results
THE OPERATIONAL MODE OF OPTICAL MICROSCOPE APPLYING PHOTONIC JET MICROSCOPY
Full text linkThe previous experimental research on microsphere parameters applying photonic jet microscopy in free space revealed if the relative indexes come near to two, it needs larger microspheres. It also means if the relative indexes come near to one, it needs smaller microsphere. In addition to these premises, the mode of ordinary optical microscope introducing photonic jet microscopy in its operation must be taken into account. That includes the light source or filter, and the fluidic environment - free space or immersion oil. These additional modes are predicted in two dimensional finite element method calculation. Which leads to more practical use of photonic jet microscopy in the near future
SEED MEDIATED SYNTHESIS OF HEXAGONAL S-DOPED ZnO NANOROD AND ITS PHYSICAL PROPERTIES
Full text linkSulfur-doped zinc oxide (S-ZnO) nanorod has been successfully synthesized via the seed-mediated hydrothermal method with different sulfur concentrations (0%, 1%, 2.5%). This research aims to study the influence of the concentration of sulfur on the structure, morphology, and optical properties of ZnO as a promising material in a wide range of applications. Crystal structure, morphology, and optical properties of the samples were characterized using X-Ray Diffraction (XRD), Field Emission Electron Scanning Microscopy (FESEM), and UV-Vis Spectroscopy, respectively. The XRD pattern shows the strongest peak at 2θ = 34.43° for crystal orientation of (002). The crystallinity properties of the S-ZnO sample are higher compared to the ZnO sample. The FESEM images of the 1% S-ZnO sample exhibit the highest nanorod density arrangement. The optical absorbance of the higher sulfur dopant possesses a higher optical absorption peak on the UV-Vis spectrum. The results indicate that S doping to ZnO can alter the structural, morphological, and optical properties of ZnO
SIMULATION OF PEAK GROUND ACCELERATION AND PSEUDO SPECTRAL ACCELERATION OF PALU EARTHQUAKE SEPTEMBER 28TH 2018
Full text linkThe devastating earthquake Mw 7.4 hit Palu City, Central Sulawesi on September 28th, 2018, at 17:02:44 WIB. A high tsunami followed it. More than 2000 people died as a result of the earthquake and tsunami disaster. The latest evidence shows that the earthquake was categorized as a rare super shear earthquake. The earthquake shaking that hit Palu City is relatively large. Acceleration data are not available at the study site due to the lack of instrumentation in the area. The Authors present a simulation of peak ground acceleration (PGA) and pseudo-spectral acceleration (PSA) due to the earthquake in three locations Tatura Mall, Roa-Roa Hotel, and Antapura Hospital. PGA describes the maximum acceleration on the ground, while pseudo-spectral acceleration describes the acceleration of earthquake shaking from buildings with various floor numbers. Simulation of PGA and PSA to the three sites used three different Ground Motion Prediction Equation (GMPE) functions, BSSA14, CB14, and CY14, with the weighting of each Next Generation Attenuation (NGA) GMPE functions. The results of PGA simulation is about 0.22-0.23 g and show that in the three study site, it is more vulnerable to spectral acceleration period T=0.3 s or building with three floors or about 1-15 floors. These correlate with the level of damage caused by earthquakes which is more impact to relatively higher buildings
ANALYSIS OF LATTICE PARAMETER, ERROR, AND THE BANDGAP ENERGY IN CADMIUM SULFIDE (CdS) SEMICONDUCTOR MATERIAL
No full textHas successfully analyzed the lattice parameter, error, and energy band gap of Cadmium Sulfide (CdS) material. CdS is a semiconductor material. In this study, the CdS used is a material with a cubic crystal structure using database from the International Center for Diffraction Data (ICDD), then the data is calculated using the Cramer-Cohen method. From these data the resulting lattice parameter of a = b = c = 5.823791777 Å with an average error of 0.00034%. The band gap energy calculation of CdS material is 2.477 eV
THE RELATIONSHIP BETWEEN TIME AND WATER CONTENT OF FISH DRIED USING SOLAR PANEL-BASED DRYERS
No full textTraditional drying of fish, the water content produced is not in accordance with SNI (Indonesian National Standard), which is less than 40%. This research aims to determine the correlation between time and water content of fish dried with an electric-based fish dryer produced from solar panels. The method used is a quantitative method. The solar panel-based electric fish dryer has a maximum capacity of 2237 grams (12 fish) with a temperature above 30°C. Based on the data analysis, the correlation between time and water content was obtained, the results for the 1st, 2nd and 3rd experiments, the average correlation coefficient was R² = 0.99, and the correlation between the mass of dried fish and the water content of fish, the more mass of fish that is dried the more water content evaporates (dry), To meet the water content of fish that is permitted according to SNI, which is less than 40%, it takes a long time to dry. about 4 days. The heating system in the drying chamber was based on the first experiment until the third experiment, the heat was evenly distributed and quite good in the drying chamber, so that the temperature control system worked well. This solar panel-based fish drying system can be used by fishermen to lighten fish in improving the quality of their products according to SNI
THE DEVELOPMENT OF IMAGE PROCESSING METHOD ON THE AUTOMATIC READING SYSTEM OF THE GLASS THERMOMETER USING A DIGITAL CAMERA
Full text linkThe reading performance of an analog thermometer, Liquid in Glass Thermometer (LiGT), can be improved using a digital camera. The aim is to minimize the human error on the reading of LiGT and increase the accuracy of temperature measurement results. In order to achieve an accurate result, a robust image processing method is required in the measurement. In this work, the LiGT image generated using a digital camera is analyzed using the technique in HSV color space which consists of some image processing methods (e.g., thresholding, morphology filter). The type of LiGT used is the glass thermometer with the colored liquid. There are three main parts to this developed technique process, i.e., identifying the scale of LiGT to calculate the pixel per temperature unit value (ppt), segmentation of the liquid column, and calculate the temperature based on the ppt value. Through simulation with a synthetic image, we demonstrate that the developed technique in this work has successfully read (measured) the temperature value of the LiGT (having a scale unit of 1oC) with a measurement error of 0.04oC. In the experimental results, we also report the developed technique performed on a real image of LiGT
THE SIMULATION OF GRANULAR PARTICLE ON DRY AND MOISTURIZED POROUS HORIZONTAL SURFACES
Full text linkSimulations were carried out to visualize the ratio of granular attachment to porous surfaces. This simulation uses a uFlex three-dimensional simulation using three sizes of porous surface systems in the condition of the smallest human pores and the most extensive human pores and the condition of wet skin and dry skin. Each system was tested using five granular particle sizes according to the range of the makeup granules’ size to determine the optimal adhesive. The results show that the number of cosmetic granular particles entering the porous surface system is directly proportional to the porous surface volume and moisture and inversely proportional to the granular cosmetic size. The larger the cosmetic granular used, the less granular enters the pore