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Spektra: Jurnal Fisika dan Aplikasinya

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Published by Universitas Negeri Jakarta

ISSN : 25413384 EISSN : 25413392 DOI : -

Core Subject : Science, Engineering,

Aerospace Engineering Electrical & Electronics Engineering Energy Materials Science & Nanotechnology Physics

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Articles 260 Documents

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UNCERTAINTY ANALYSIS OF LABORATORY MEASUREMENT OF AIRBORNE SOUND INSULATION Bondan Dwisetyo; Maharani Ratna Palupi; Fajar Budi Utomo
Spektra: Jurnal Fisika dan Aplikasinya Vol 5 No 2 (2020): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 5 Issue 2, August 2020
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.052.02

The evaluation and analysis of the uncertainty of laboratory measurement of airborne sound insulation have been carried out by Research Group for Acoustics and Vibration – National Standardization Agency of Indonesia (BSN). The aims of this work are to evaluate and analyze the uncertainty measurement of airborne sound insulation by pressure method, where it is focused only for the determination of sound transmission loss (STL) as a major product of this measurement according to ASTM, and guide to the expressions of Uncertainty in Measurement (GUM) provided by JCGM. The supplied parameter of uncertainty budgets includes measurement of sound pressure level (SPL) in a source room (L1), and measurement of some parameters in a receiver room such as SPL (L2), reverberation time (RT60), background noise (B), test opening area (S), and volume of receiver room (V). From the result of the case study, the source of uncertainty that has a top contribution for obtaining expanded uncertainty is considered as the repeated measurement of the measured parameter such as L1, L2, and RT60 at the frequency range 250 Hz – 315 Hz. Meanwhile, the standard uncertainty that provided by the calibration certificate also contributes to the final result, where it is supplied by an acoustic calibrator and sound analyzer, respectively. Furthermore, the sources obtained from the readability parameter has a slight effect on this whole result. Therefore, the maximum and minimum value of expanded uncertainty is determined that their values are 0.70 dB and 0.43 dB for the frequency of 315 Hz and 1600 Hz, respectively.

GEOPHYSICAL FORENSIC FOR ARCHAEOLOGICAL EXPLORATION IN MUAROJAMBI, INDONESIA Bambang Sugiarto; Dicky Muslim; Iyan Haryanto; Zufialdi Zakaria; Emy Sukiyah; Vijaya Isnaniawardhani; Achmad Djumarma Wirakusumah; Heryadi Rachmat
Spektra: Jurnal Fisika dan Aplikasinya Vol 5 No 3 (2020): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 5 Issue 3, December 2020
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.053.06

In July 2011, archaeological exploration tried to apply the physics method for the first time in Muarojambi, Indonesia. We combined physics with geosciences and called it geophysical forensic. Our method is known as Ground Penetrating Radar (GPR). GPR used high-frequency electromagnetic (EM) waves between 10-3000 MHz to imaging subsurface based on dielectric permittivity’s physical parameters. Changes in the electrical properties, rock magnetism, and water content of the material under the surface will provide a response recorded on the radargram as a function of distance to time (two-way travel time). Data processing performs to reduce the noise recorded when collecting data. We have successfully obtained four GPR lines; three lines gathered near Gumpung Temple and one line at Telago Rajo Pool. The GPR method succeeded in giving a subsurface image and possibility of the archaeological objects near the Gumpung Temple and Telago Rajo Pool.

A PRELIMINARY STUDY OF RADIATION QUALITY CORRECTION FACTOR (KQ) DETERMINATION FOR WELL-TYPE IONIZATION CHAMBER Assef Firnando F; Okky Agassy Firmansyah; Cahya Wulandari; R. Pramuji Ramadhani S
Spektra: Jurnal Fisika dan Aplikasinya Vol 5 No 2 (2020): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 5 Issue 2, August 2020
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.052.05

This paper deals with the determination of the radiation quality correction factor (kQ) well-type ionization chamber for the measurement of Co-60 brachytherapy. The measurement of the brachytherapy source has been done in the hospital brachytherapy facilities. The measurement of air Kerma has been done using three different ionization chambers 0.6 cm3, 30 cm3, 80 cm3, which have calibration factor traceability for Co-60 and one well-type ionization chamber which calibrated for Ir-192. The determination of the radiation quality correction factor (kQ) was determined based on the results of the air Kerma ratio between measurements using ionization chambers, which have traceability to Co-60 and Ir-192 sources. The results of the measurement of the reference air Kerma rate (RAKR) obtained from the three chambers were 21.36, 19.87, 19.34 mGy.m2.h-1, while the results of measurements with ionization chambers get a value of 19.01 mGy.m2.h-1. The kQCal results from 0.6 cm3 ionization chamber get a value of 1.07. The kQCal value was compared with the value of Andreas Schuller’s et al. kQreff of 1.05 and get a deviation of 2.2%. Implementation of the booth kQ value on the results of the RAKR from the HDR1000Plus well-type ionization chamber in the measurement of brachytherapy in two different facilities gets a maximal deviation 1.7% with dose value from Treatment Planning System (TPS). The deviation was in the acceptable range of ±5%. Based on this, the use of radiation quality correction factor (kQ) value can be implemented as one method if it does not have the traceability factor calibration of the Co-60 brachytherapy source.

ANALYSIS OF A PEAK GROUND ACCELERATION VALUE AND EARTHQUAKE INTENSITY USING DONOVAN METHOD IN BANTEN PROVINCE Elsi Ariani
Spektra: Jurnal Fisika dan Aplikasinya Vol 5 No 3 (2020): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 5 Issue 3, December 2020
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.053.05

Analysis of a peak ground acceleration value and earthquake intensity in Banten Province has been carried out using historical earthquake data from 2008 to 2018. This research aims to describe a prone area of the earthquake. The specification of data was a magnitude > 5 SR and the depth 0-70 km. The Donovan method was used to analyze peak ground acceleration value and the earthquake’s intensity. According to the data obtained, 31 earthquake points with a maximum earthquake strength occurred on October 16, 2019, with a depth of 10 km and a magnitude of 6.48 SR. This earthquake was located in Ujung Kulon with coordinates -6.81 LS and 105.113 BT. Based on data analysis result was obtained a peak ground acceleration value and the intensity of earthquake maximum in The Pandeglang Regency with a peak ground acceleration value was 211.56 cm/s2, and intensity of scale VIII and a large risk level of three. While a peak ground acceleration minimum is located in the South Tangerang City was 62.82 cm/s2 with a scale of intensity VII and a moderate risk level.

THE COMPATIBILITY OF MODEL FOR LOW SHEAR FLOW ANALYSIS IN DEVELOPING PLASTICIZED HTPB-BASED BINDER Afni Restasari; Luthfia Hajar Abdillah; Retno Ardianingsih; Bagus Wicaksono; Rika Suwana Budi
Spektra: Jurnal Fisika dan Aplikasinya Vol 5 No 3 (2020): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 5 Issue 3, December 2020
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.053.03

In developing flow behavior of plasticized prepolymer as liquid content of composite solid propellant, zero shear viscosity (ZSV) is a critical parameter that Goh-Wan equation is developed to model it recently [1]. Thus, this work aims to analyze the compatibility of the Goh-Wan equation toward the liquid content of propellant, characterize it, and determine the limit. In this work, a varied flow behavior index was obtained by using Hydroxy terminated polybutadiene (HTPB) and HTPB-DOA (Dioctyl adipate) system with the variable of its concentration, pre-heating, and pre-stirring methods as samples. Viscosity was measured at 2, 3, 4, and 5 rpm by using the disc spindle of Brookfield viscometer. For the minimum shear-rate investigation, as a limit of compatibility, other three sets of shear rates are applied, which are 0.6 – 5 rpm, 1 – 5 rpm, and 1,5 – 5 rpm. By functioning Goh-Wan equation (model 1) and Power-Law (model 2), a model was categorized as compatible if yields lower value of ZSV than the first experimental measured viscosity (η1st). Characterization was determined by a graph of plotting percentage difference of ZSV obtained from models 1 and 2 towards the index of flow behavior. The 3% of the difference between ZSV obtained from model 1 and η1st was set to be a minimum value for a set of applied shear-rate to be acceptable. It is reported that the Goh-Wan model is compatible with the liquid content of propellant and characterized by a perfect linear correlation. It is also found that a minimum applied shear rate of 1.5 rpm is acceptable for model compatibility.

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 Ayi Bahtiar; Khairul Habibie
Spektra: Jurnal Fisika dan Aplikasinya Vol 5 No 2 (2020): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 5 Issue 2, August 2020
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.052.03

Perovskite 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 INFLUENCE OF SURFACTANT AND PROTECTIVE COLLOID ON POLYVINYL ACETATE EMULSION SYNTHESIZED BY EMULSION POLYMERIZATION TECHNIQUE Adam Jaya; M. A. Elita Hafizah; A. Manaf; Andreas Andreas
Spektra: Jurnal Fisika dan Aplikasinya Vol 5 No 3 (2020): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 5 Issue 3, December 2020
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.053.01

A series of experiments have been carried out and reported. This report describes the stages of the polymerization reaction during emulsion Polyvinyl Acetate (PVAc) synthesis. PVAc was synthesized from the Vinyl Acetate Monomer (VAM) with Ammonium Peroxydisulphate (APS) as an inorganic thermal initiator in the aqueous media under reaction temperature was keep at 65 until 75oCs by agitation speed was 300 rpm respectively during 4 hours of reaction time. The protective colloid agents and several types of surfactants were added to improve the obtained emulsion PVAc performance. The polymerization reaction was carried out without the addition of a protective colloid agent. The surfactants were produced the emulsion PVAc with the properties of solid content 0.89%, density 1.02 g/ml, viscosity 0.0033 Poise, pH 2.8, conductivity 12 ms, respectively. While the polymerization reaction involved protective colloid agents by using Polyvinyl Alcohol (PVOH) was obtained properties of emulsion PVAc with Solid Content 4.36%, density 1.17 g/ml, viscosity 0.0216 Poise, pH 2.8, and conductivity 10 ms respectively. The same thing was shown when the surfactant was present in the polymerization reaction. The emulsion PVAc was synthesized with nonionic surfactant has solid content 8.20%, density 1.17 g/ml, viscosity 0.0099 Poise, pH 2.8, and conductivity 7 ms, the result is better rather than synthesized with anionic surfactant has solid content 2.65%, density 1.13 g/ml, viscosity 0.0068 Poise, pH 2.8, and conductivity 11 ms. According to the preliminary observations obtained, emulsion PVAc’s appearance is better when the protective colloid agents and the surfactant is present rather than without additional those substances. The physical properties of emulsion were depended on the addition of protective colloid agents and surfactants. In addition, the complete reaction indicated by solid content value was obtained from emulsion when the additional substances were present. All the testing parameters were observed using Viscometer Ostwald, Pycnometer, pH Meter, FTIR Spectrophotometer, Conductometer, and another supporting testing to explain the polymerization reaction stage of synthesis emulsion PVAc.

THE CHANGE OF ROCK CONDITION OBSERVED BY H/V SPECTRAL AND ELLIPTICITY CURVE INVERSION ANALYSIS (CASE STUDY: PALU EARTHQUAKE SEPTEMBER 28, 2018) Sandy Tri Gustono; Muhammad Akhadi; Kekey Salsabil Azzahra; Rika Adelina Ginting
Spektra: Jurnal Fisika dan Aplikasinya Vol 5 No 3 (2020): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 5 Issue 3, December 2020
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.053.04

Palu 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.

THE MONITORING SYSTEM OF INDOOR AIR QUALITY BASED ON INTERNET OF THINGS Agung Pangestu; Muhammad Yusro; Wisnu Djatmiko; Ariep Jaenul
Spektra: Jurnal Fisika dan Aplikasinya Vol 5 No 2 (2020): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 5 Issue 2, August 2020
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.052.06

The 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 MAGNETIC PROPERTIES MEASUREMENT OF COIL FOR GRAVITATIONAL ACCELERATION DETERMINATION Cherly Salawane; Supriyadi Supriyadi; Ronaldo Talapessy; Mirtha Yunitha Sari Risakotta
Spektra: Jurnal Fisika dan Aplikasinya Vol 5 No 2 (2020): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 5 Issue 2, August 2020
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.052.04

The value of the gravitational acceleration of the earth above the earth’s surface depends on the position of the latitude and longitude of the earth’s surface, in other words, because the shape of the earth’s surface is not round like a ball. The magnitude of gravity is not the same everywhere on the surface of the earth. The purpose of this study is to analyze the value of the earth’s gravitational acceleration in a laboratory using a current balance with a graphical method. Fluctuations in the value of the magnetic field strength (B) and the value of the electric current strength (i) on the current balance cause the value of laboratory gravitational acceleration (glab) to vary in the transfer of electric charge (q) according to coil type. The magnitude of the earth’s gravitational acceleration value obtained in a laboratory with a current balance for each type of coil is as follows: SF-37 glab-nr=9.89 m/s2, SF-38 glab-nr=9.90 m/s2, SF-39 glab-nr=9.76 m/s2, SF-40 glab-nr=9.95 m/s2, SF-41 glab-nr=9.75 m/s2 dan SF-42 glab-nr=9.93 m/s2. The results obtained indicate that the value of the earth’s gravitational acceleration in a laboratory close to the literature value is the value of the glab-nr in the SF-37 coil type of 9.89 m/s2.

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