Jurnal Ilmu Fisika (JIF)
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Prototype of Rainfall Intensity Measurement Using CCD TSL1401CL Linear Sensor Array
Get PDFA prototype measurement of rainfall intensity was developed using a CCD TSL1401CL linear sensor array. The prototype consists of a He-Ne laser that functions as a light source, which later is focused by the beam expander and conditioned by a convex lens. Each pixel will receive the same voltage depending on the light intensity so that it produces a decimal value of ADC. This ADC decimal value determines rainfall intensity based on the diameter and velocity of the raindrops. The diameter variations used ranges from 1 mm to 10 mm, while for variations in the height of rainfall are 50 cm, 100 cm, and 150 cm. The test results proved that the greater the decimal value of the ADC is, the smaller the diameter of the raindrops detected will be, and vice versa. The values of the diameter and velocity of were used to obtain the value of rainfall intensity. The percentage value of error measuring rainfall intensity is 3.11% when compared to the rain gauge module is still considered rather accurate. However, direct testing is still needed when rain falls with various types and intensities. Â
Analysis of Fill Weight, Water Absorption and Density of Plasterboard Ceiling Made of Banana Midrib Fiber
Get PDFThe plasterboard ceiling is one of the applications of fiber-based composite materials. Asbestos fibers, usually used to make plasterboard ceilings, are unfortunately harmful to humans. We propose using banana midrib fibers that are environment-friendly to replace asbestos fibers. This research investigates the influence of the percentage of banana midrib fibers on the fill weight, water absorption, and density of plasterboard ceilings. The fibers extracted from banana midrib were immersed in 40 mL of 1 M NaOH and then used to prepare plasterboard ceiling samples with different fiber percentages, namely 0.0%; 1.0%; 1.5%; 2% 2.5%. The fill weight, water absorption, and density of plasterboard samples were measured and then compared to Indonesian National Standard. The highest fill weight of 1.52 g/cm3 was obtained with a 1.0% percentage of banana midrib fibers for the plasterboard sample. In contrast, the highest water absorption of 11.84% was obtained at 2.5% banana midrib fibers. The more fibers added, the better the seepage of the plasterboard ceilings.Â
Statistical Comparison of IMERG Precipitation Products with Optical Rain Gauge Observations over Kototabang, Indonesia
Get PDFSatellite-based precipitation estimates play a crucial role in many hydrological and numerical weather models, especially to overcome the scarcity of rain gauge data. Globally gridded rainfall product from Integrated Multi-Satellite Retrievals for Global Precipitation Measurement (GPM) (IMERG) has been used in a wide range of hydrological applications. However, the IMERG is inherently prone to errors and biases. This study evaluated the performance of the IMERG-Final run (IMERG-F) product to estimate rainfall in a mountainous area of Sumatra. Validation was carried out using optical rain gauge (ORG) data for 15 years (2002-2016), at Kototabang, West Sumatra, Indonesia. In general, IMERG-F overestimated rainfall in all time scales. The longer the time scale was, the better the performance of IMERG-F we obtained. This feature was indicated by all quantities of continuous and categorical statistical matrices used. The performance of IMERG-F was lower than in other areas of the Maritime Continent, except for the probability of detection (POD) value. IMERG-F could detect rain very well, including for daily and hourly data, but the false alarm rate (FAR) was also relatively high. Such high FAR value may indicate a significant small-scale spatial rainfall variability in mountainous area of Sumatra
Characterization of Multiple-bend Optical Fiber Extensometer Design for Landslide Sensor
Get PDFDesign of multiple-bend extensometer based on optical fiber as landslide sensor has been characterized. Multiple-bending characterization has been done by varying the winding number of optical fiber FD-620-10 to obtain the photodiode's effective light intensity. The light intensity in the extensometer was set by varying the laser diode resistance in the range (150 – 250) Ω. The optimum sensitivity of 0.03984 V/cm was obtained for triple winding of optical fiber. The designed optical extensometer is able to monitor the displacement with an error of 0.59%. This result indicates that the designed extensometer is the more bending on optical fiber, the more its sensitivity and the bending loss
Modeling of Dynamics Object with Non-Holonomic Constraints Based on Maple in Cylinder Coordinate R×S^1×SO(3)
Get PDFReliable real-time planning for dynamic systems is crucial in today's rapidly growing automated ecosystem, such as the environment and methods of planning a robotic system. This paper describes the rigid dynamics system with non-holonomic constraints on the R×S^1×SO(3) configuration space. The method used is the motion planning network and numeric treatment using physics computation which can be used for non-holonomic object systems that move in real-time with Jellets Invarian (JI) approach. The JI approach can result in a motion system equation and evaluate the model of an object with non-holonomic constraints and also display experimental results for navigation in the R×S^1×SO(3) configuration space. The motion system with non-holonomic constraints used is Tippe top (TT). TT is a toy like a top which when rotated will flip itself with its stem. The author have finished in simulating the dynamics of TT motions in real time with the initial states that have been described with various coordinate in the  configuration space. Based on the results of previous studies on similar objects, TT was solved by the Eular-Lagrange Equation, Routhian Reduction Equation and Poincare. The author succeeded in describing the dynamics of TT motion in real time with predetermined initial conditions with various coordinates in the R^2×SO(3) configuration space
Differences in Mechanisms of Orographic Rainfall over West Sumatra (Case Study: 10 April and 23 April 2004)
Get PDFTwo different mechanisms of orographic rainfall enhancement  in West Sumatra were investigated utilizing observed data during the Coupling Processes in the Equatorial Atmosphere (CPEA)-I campaign. The variation of the atmospheric conditions during the campaign was shown by rainfall, surface wind, humidity, and stability index. An X-band Doppler radar captured the atmospheric conditions related to the enhancement of orographic rainfall mechanisms. The dry and less stable atmospheric conditions resulted in the convective type of rainfall. In contrast, the humid and stable atmospheric conditions brought the large-scale rainfall in the mountainous region where the events took place coincided with the inactive and active MJO phases.
Identification of Environmental Change in Bukit Kerang, Aceh Tamiang Regency Using Landsat Satellite Imagery
Get PDFChanges in land cover and temperature in Bukit Kerang have been investigated using Landsat satellite images. We used Landsat 5 TM Landsat satellite imagery in 1988, Landsat 7 ETM in 2000, and Landsat 8 OLI in 2020. The ENVI 4.7 and ArcGIS 10.3 software was used to perform radiometric corrections, image cropping, image classification, image reclassification, calculating area, and layouts. Changes in land cover and land area in 1988, 2000, and 2020 affected the surface temperature conditions in those three years. In 1988, the dominant land area of forest cover was 5,926.44 ha (1 ha = 104 m2), with the dominant temperature distribution of 17.2° C. In 2000, there was an increase in settlements by 25.56 ha and rice field area, which caused an increase in the temperature distribution of 19.7 – 25.4° C. In 2020, forest type land cover changes into plantations, fields, and settlements decreased by 3,731.91 ha, increasing temperature distribution of 20.6 – 21.8° C. Thus, there is a strong relationship between changes in land cover and change in surface temperature in Bukit Kerang area
Identification of Sand Mineral Content at Beach Tourist Attractions in Sampang Regency through X-Ray Fluorescence and X-Ray Diffraction Testing
Get PDFResearch on the natural mineral content in Sampang Regency has been conducted, namely Camplong Beach, Nepa Beach, and Mandangin Island. The XRF results show that the silica mineral content in Camplong sand at a depth of 0.5 m, 1 m, and 1.5 m are 54.6%, 53.2%, and 57.0%, respectively. Nepa sand shows the highest mineral content is calcium. The calcium content at a depth of 0.5 m, 1 m, and 1.5 m are 51.7%, 58.3%, and 63.0%, respectively. Mandangin Island sand shows the highest calcium content that are 94.69%, 94.65%, and 94.98%, at a depth of 0.5 m, 1 m, and 1.5 m, respectively. XRD test results show that in Camplong sand at a depth of 0.5 m, 1 m, and 1.5 m, SiO2 phase < 94% is formed. In Nepa sand at a depth of 0.5 m, 1 m, and 1.5 m, the SiO2 phase < 80% is formed. For Mandangin Island beach sand with a depth of 0.5 m, 1 m, and 1.5 m, the CaCO3 phase > 90% is formed. This study's results can determine the mineral content of sand, which can be used as a high-tech material to minimize illegal mining
Characterization of (Mg1.0Zn0.0)TiO3+4 wt%Bi2O3 Ceramics for Application as Resonator in Dielectric Resonator Oscillator Circuit
Get PDFMgTiO3-based ceramics have potential applications in telecommunications systems at microwave frequencies, such as resonators in dielectric resonator oscillator (DRO) circuits. This paper reports the results of (Mg1.0Zn0.0)TiO3+4wt% Bi2O3 (abbreviated MZT0+4wt%Bi2O3) ceramic fabrication to assess its potential to be used as a resonator in the DRO circuit. We characterized its structure, microstructure, and bulk density. The addition of 4wt%Bi2O3 to MZT0 crystalline powder was carried out via ball-mill. The milled powder was compacted using a die press to obtain pellets. All pellets were sintered at 1100ºC for 4, 6, and 8 h. Ceramic structures of the 4 and 6 h holding time consists of MgTiO3 phase (94.33±2.68) and (95.34±1.95)% molar respectively, while the rest phase was TiO2. The 8-h ceramic structure comprises (96.11±2.94) % molar MgTiO3 accompanied by Mg2TiO5 and TiO2. The ceramics' microstructure consists of a cluster of grains with an average diameter of 1.32-2.24 μm and pores. Bulk density decreases with the increase of sintering holding time. The DRO characterization records a resonance signal each at 5.207, 5.005, and 5.121GHz with power approaching 0 dBm, suggesting that the MZT0+4wt%Bi2O3 ceramics can be used as a resonator in the DRO circuit working in microwave frequencies, especially at 5.0-5.2GHz
Effect of Citric Acid on Electrochemical Properties of Liquid Electrolytes
Get PDFEffect of citric acid as plasticizer on the electrochemical properties of liquid electrolyte has been studied. Liquid electrolyte was prepared by dissolving citric acid in 1% acetic acid with presence of lithium nitrate salt. Liquid electrolyte is characterized using a conductivity meter to measure the ionic conductivity value. Computer simulation of Density Functional Theory (DFT) with B3LYP/6-31G ++ (d, p) basic set was performed to identify the dominant functional group of citric acid when interact with lithium salt. Increasing the weight of citric acid has increased the ionic conductivity up to 44.89 mS/cm with an optimum weight of 4 g, while the ionic conductivity increases up to 43.00 mS/cm when the percentage of lithium nitrate salt increases up to 30%. The ionic conductivity increases as the salt percentage increases due the interaction between salt and functional group of citric acid. Based on computer simulation of DFT, Â the dominant functional group in citric acid that interact with lithium salt are carboxylic acid group which is located in the middle of the citric acid chain causing lithium ions to be more likely interact with citric acid