Indonesian Physical Review

DETERMINING THE RELATIONSHIP BETWEEN TEMPERATURE AND TUNING FORK FREQUENCY CHANGES WITH POLYNOMIAL REGRESSION MODELLING

Aly Hasan, Adrianus Inu Natalisanto, Ahmad Zarkasi — Mon, 05 Feb 2024 00:00:00 +0000

A tuning fork is a unique tool made of metal and shaped like the letter U, with one handle. Tuning forks can produce specific frequencies; usually, the value is written on the handle. This study aims to investigate the relationship between temperature and changes in tuning fork frequency and model it using polynomial regression. This research uses laboratory experiments with tuning forks with 341.3 Hz, 426.5 Hz, and 512 Hz frequencies. The temperature on the tuning fork varies from 30C to 220C with a difference of 10C. From the results of the study adjusted R-Square values sequentially 0.94745, 0.99565, and 0.97721, which stated the relationship between temperature and frequency changes. The Adjusted R-Square value close to 1 means that changes in temperature on the tuning fork greatly influence changes in the frequency produced by the tuning fork, and the polynomial regression model used is very suitable.

THE EFFECT OF BARIUM SUBSTITUTION WITH COMBINATIONS OF RARE EARTH ON PERMANENT MAGNETIC SURFACE MORPHOLOGY BASED ON BARIUM HEXAFERRITE

Tue, 05 Mar 2024 00:00:00 +0000

The development of hard magnets today is progressing very rapidly. Developing hard magnets based on rare earth metals becomes a severe problem when the raw materials are not readily available. The chosen solution is to replace oxide-based permanent magnets with small amounts of rare earth metals substituted to improve their magnetic properties. This study synthesized a permanent magnet oxide based on barium hexaferrite doped with lanthanum and cerium atoms. In the synthesis of this material, a mechanical wet milling technique is used to obtain a single-phase permanent magnetic Ba_1-β-γLa_βCe_γFe₁₂O₁₉ system with composition (β = 0 - 0.5 and γ = 0 - 0.1). The precursors are weighted according to their stoichiometric composition. Each mixed composition was milled by high energy milling (PW 1000 in the mixer/mill) at a milling speed of 1000 rpm using steel balls with an average diameter of 12 mm. Grinding conditions included a ball-to-powder weight ratio of 2:1, milling time 5 hours, then compacted with 7000 Psi pressure and sintered at 1200^oC for 2 hours. The surface morphology and microstructure of the resulting sample particles were observed using scanning electron microscopy (SEM) with the SEM JEOL JED 305 brand. The characterization results show that the particles are hexagonally homogeneous in shape with particle sizes in the range of 1000-2000 nm for β = 0 and γ = 0 (without doping). In general, the four samples with varying concentrations of doping ions La³⁺ and Ce⁴⁺ showed homogeneous hexagonal structures but smaller particle sizes than pure barium hexaferrite. The sample particle sizes ranged from 500-1000 nm for β = 0.02 and 300-1000 nm for β = 0.04.

FABRICATION OF THERMAL BIO-INSULATOR FROM OIL PALM TRUNK FIBER: ANALYSIS OF THERMAL, PHYSICAL AND MECHANICAL PROPERTIES

Tue, 05 Mar 2024 00:00:00 +0000

The majority of air conditioning systems, including both cooling and heating systems, consume a significant amount of electrical energy as a result of their high electrical consumption and prolonged periods of operation. The use of thermal insulation materials in the building can help conserve electrical energy used for room conditioning systems. Natural fibers are used as an alternative in the production of thermal insulation, which is commonly referred to as bio-insulators. The utilization of oil palm trunk (OPT) fiber as the primary material for thermal insulation shows promise. This study aims to determine the specific attributes of OPT fiberboard that make it suitable for use as a thermal bio-insulator. The features examined encompass physical, mechanical, thermal, and fire-resistant attributes. The OPT fiber underwent a treatment process involving boiling at a temperature of 80℃ for a duration of 30 minutes. The fiberboard is manufactured using epoxy adhesive and calcium carbonate additive, and then printed using the hand lay-up process and cold-compaction technique. The physical characteristics of fiberboard indicate that there is a direct relationship between its density and water absorption. Testing revealed that fiberboard has a low thermal conductivity and high heat capacity value. By including calcium carbonate, the burning time of the fiberboard was tested and seen to decrease, indicating a delay in the fiberboard burning process, as evidenced by the extended flame suppression time. The density of OPT fiberboard varies between 0.48 and 0.70 gr/cm³. The absorbency of water is inversely related to its density. Water absorption capacity generally rises with decreased density. The obtained heat capacity value is 1.28-2.38 J⁄(g℃). The mechanical value ranges from 1.00 to 3.55 MPa. The incorporation of calcium carbonate significantly impacts the thermal and mechanical characteristics of the fiberboard. The produced OPT fiberboard satisfies the requirements for good thermal, physical, and mechanical characteristics, making it a suitable bio-insulation material for buildings.

HYPOCENTER DISTRIBUTION ANALYSIS OF SINABUNG VOLCANO ERUPTION IN 2021 USING GEIGER'S WITH ADAPTIVE DAMPING (GAD) METHOD

Tue, 05 Mar 2024 00:00:00 +0000

Sinabung Volcano is located in the Karo Highlands, Karo Regency, North Sumatra, Indonesia, with a peak of 2460 meters above sea level. This volcano experienced an increase in volcanic activity in the April-October 2021 period, so it is necessary to analyse volcanic seismicity to determine the hypocenter distribution of the volcano. This study aims to determine the hypocenter distribution and classification of volcanic earthquake types based on seismogram recording data of Sinabung Volcano at four stations, namely LKW, BGR, MDD and SGR stations. The method used in this research is Geiger's method with adaptive damping (GAD) to determine the distribution of hypocenters. The results showed that the hypocenter distribution gathered below the crater centre with depths from 0.172 km to 7.139 km. The determination of the hypocenter distribution of volcanic earthquakes is expected to provide information on the depth of the earthquake to determine the movement of magma and the characteristics of events that occur during the pre-eruption process of Sinabung Volcano so that this data can be used for mitigation decision making when there is an increase in the activity of Sinabung Volcano.

SPECTRUM AND TIME-FREQUENCY ANALYSIS TO CHARACTERIZE MICROTREMOR DATA IN SEPAKU SUB-DISTRICT, EAST KALIMANTAN

Wed, 06 Mar 2024 00:00:00 +0000

Microtremor analysis has been done in the Sepaku Sub-District as a part of the New Capital City of Indonesia. This study aims to determine the characteristics of microtremors in the Sepaku Sub-District using Spectrum Analysis and Time-Frequency Analysis (TFA). Data in this study were taken using a seismometer on the 18 measurement points. The data were processed using default analysis from Geopsy software. Spectrum analysis and TFA used Fourier Transform to change time domain data into the frequency domain. Both analysis ways result in the characteristic microtremor data in the research area. The spectrum analysis data obtained shows two frequency ranges with maximum peaks: middle-frequency (5-8.8 Hz) and high-frequency (11.5-17.6 Hz). Afterward, the TFA shows similar results, where the characteristics of microtremor data are divided into two zones. The maximum peak occurs at the middle-frequency range of 5-10 Hz, and the high frequency ranges above 10 Hz

DESIGN OF AN AUTOMATIC HANDWASHING TOOL USING INFRARED SENSOR BASED ON ARDUINO NANO IN PHYSICS DEPARTMENT OF SRIWIJAYA UNIVERSITY

Wed, 06 Mar 2024 00:00:00 +0000

The implementation of the New Normal forces people in Indonesia to be able to return to their activities outside the home, alongside the risk of the COVID19 outbreak. One of the health protocols that must be applied is hand washing, so that the use of automatic hand washing devices is very effective in use. The way this automatic hand washing tool works is simply pointing your hand near the sensor, the sensor will detect it. The Automatic Hand Washing Tool is designed using a sensor Infrared, Arduino nano, a module Relay, a water pump and a solenoid faucet. Where is the working principle when thesensor infrared detects an obstacle, it will send an input signal to arduino nano as a microcontroller center which is regulated through a program in the Arduino Ide software, then sends it to themodule relay as answitch on / off, When on it is, themodule relay will activate the solenoid faucet, if it is in thecondition off , the relay will deactivate the solenoid valve, while the pump is used for washing soapy water, where the automatic hand washing tool on water with soapy water is differentiated according to the respective distance that has been set on the arduino nano microcontroller.

INVESTIGATION OF GROUNDWATER SOURCES IN BANYOL HAMLET MALANG REGENCY USING THE GEOELECTRICAL RESISTIVITY METHOD TO OVERCOME DROUGHT STRATEGY

Tue, 02 Apr 2024 00:00:00 +0100

The drought in Banyol Hamlet, Malang Regency, severely impacts community sustainability. This problem can be overcome if the hamlet has a groundwater source; theoretically, groundwater can be detected using geoelectric resistivity. This research aims to investigate the existence of aquifer layers in Banyol Hamlet, Malang Regency, using the resistivity method Schlumberger configuration. Resistivity data was measured at 5 points with a track stretch of 400 m and a distance between electrodes of 5 m; then, three parallel measurement points were interpolated into a 2D cross-section. Based on the analysis, the presence of the aquifer is considered to be in the breccia tuff layer because the resistivity value is lower than usual in this layer. So, we assume that the tuff breccia rocks can act as an aquifer in the study area. The results of the 2D cross-section show that the shallow aquifer is found at a depth of 10-22 m with a resistivity value of around 30.78 Ωm - 314 Ωm. and a deep aquifer at a depth of 40-125 m with a resistivity value of around 22.34 Ωm - 192 Ωm. So drilling is recommended at measurement points SS-1 and SS-3 in deep aquifers because the thicker the soil layer, the more water infiltration.