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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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ANALYSIS OF STRUCTURE AND ANTIMICROBIAL ACTIVITY OF CeO2 AND Nd2O3 NANOPARTICLES Hanif Yuliani; Rina Dewi Mayasari; Eryanti Kalembang; Yelvia Deni; Defi Rahma Santi; Putri Widya Pangestika; Setyo Purwanto; Bambang Sugeng; Suyanti Suyanti; Moch. Setyadji
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 3 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 3, December 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Cerium oxide (CeO2) and Neodymium oxide (Nd2O3) nanoparticles using local content have been synthesized by precipitation method. The CeO2 and Nd2O3 nanoparticles were characterized by X-Ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) to analyze the material phase and structure. The XRD spectrum shows that CeO2 and Nd2O3 nanoparticles have face-centered cubic and hexagonal, and cubic, respectively. The anti-microbial activity of CeO2 and Nd2O3 nanoparticles was analyzed by diffusion method using gram-negative bacteria (E. coli, S. aureus, P. aeruginosa), and gram-positive bacteria (S. entericatyphi, L. monocyogenes), and fungus (C. albicans). The result confirms that CeO2 and Nd2O3 nanoparticles have the capability of microbial pathogen inhibition. The CeO2 nanoparticles have the effective activities of inhibition for the microbial of S. aureus and S. entericatyphi, whereas Nd2O3 nanoparticles can inhibit the microbial of P. aeruginosa, S. entericatyphi, and L. monocyogenes.

BURIED WAVEGUIDE POLYMETHYLMETHACRYLATE MODELING FOR REFRACTIVE INDEX SENSOR APPLICATION USING FINITE ELEMENT METHOD Ian Yulianti; Jauhar Azka; Ngurah Made Darma Putra; Budi Astuti
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 3 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 3, December 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

The purpose of this study is to obtain the optimum buried waveguide structure through modeling for refractive index sensor applications. The waveguide cladding material used as Polymethylmethacrylate (PMMA). The core cross-section size was 1 × 1 mm2. The simulation was carried out at a wavelength of 650 nm using the Finite Element Method (FEM). The parameter of the buried waveguide optimized in this model was the core refractive index and the thickness of the upper cladding to obtain a high propagation constant and good sensitivity to refractive index. Modeling was done for various core refractive index values varied in the range of 1.52 to 1.59, which are the refractive index of various types of polymers. To optimize the sensitivity, the thickness of the upper cladding was varied between 0.125mm to 0.5mm. Besides, a simulation was also carried out for a waveguide without an upper cladding. The results show that the optimum waveguide is a waveguide without upper cladding using polyester as core material with a refractive index value of 1.57 and a sensitivity of 4.9 × 10-10rad /m. RIU.

THE APPLICATION OF SHIFT METHOD USING MOVING LASER ON CANCER CASES IN HEAD AREA USING 3DCRT AND VMAT TECHNOLOGY Samsun Samsun; Nursama Heru Apriantoro; Rudi Kurniawan; Agnes Dwika Septiti
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 3 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 3, December 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

The accuracy of patient position is essential to achieve the purpose of radiotherapy. Therefore, before radiotherapy, the isocenter of the patient must be determined to find out the target location. Verification serves to determine the isocenter that shifts from the reference point on the CT simulator. This research was conducted using field observation method, comparing the results of the isocenter after verification with the isocenter on the moving laser. Eight (8) samples from primary data were taken. Shift data was obtained from the average value and standard deviation. The instrument used was a linear accelerator of clinic iX type and On-Board Imager. The results obtained were the average lateral coordinate point of 0.055 cm; at the longitudinal isocenter point of 0.10 cm; and at the vertical isocenter point of 0.053 cm. From this research, it was concluded that the average value o the isocenter shift was less than 0.3 cm. This method can be used because the shift does not exceed the tolerance limit.

FRONT MATTER SPEKTRA VOLUME 4 ISSUE 3, DECEMBER 2019 Editor Spektra
Spektra: Jurnal Fisika dan Aplikasinya Vol 4 No 3 (2019): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 4 Issue 3, December 2019
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.04300

CHARACTERISTICS OF RAINFALL AND PRECIPITABLE WATER IN THE ANNUAL AND SEMIANNUAL RAINFALL IN THE AREA WITH VARIOUS INTENSITY OF EL NINO (SUMATERA CASE STUDY) Agus Safril
Spektra: Jurnal Fisika dan Aplikasinya Vol 5 No 1 (2020): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 5 Issue 1, April 2020
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Indonesia has a range of islands in the maritime continent which surrounded by oceans with strong cloud convection. El Nino events at weak, medium, or strong intensity can cause different effects of convection. Based on these conditions, it is necessary to analyze the characteristics of rainfall when El Nino occurred in Sumatra. The analysis was carried out by looking at the percentage of dominant frequency events of Normal (N), Normal (N), and Above Normal (AN) rainfall in El Nino years. The analysis was also carried for the relationship between the content of precipitable water and sea surface temperatures in the Central Pacific (Nino of 3.4 indexes). The results of the analysis show that the effect of El Nino (in the annual rain cycle) is stronger than the region with the semi-annual rain cycle. The annual rain cycle area in the El Nino intensity category is weak, medium, strong (predominantly BN-N rain characteristics). In the semi-annual rainfall cycle (rainfall between N-AN) it is medium (BN-AN), and strong (N-BN). The average composite percentage in the years of EL Nino shows a weak intensity with the average of rain BN between 37-50%, medium (42-53), and strong (42-48%). Whereas in the annual cycle region, the average rainfall characteristics of the BN category are weak (50-58%), moderate (36-56%), and strong (32-60%). Characteristics of different rain characteristics are due to differences in the atmospheric ability to capture moisture. Correlation in the region with the annual rain cycle (June-July-August) between the Nino 3.4 Index and the precipitable water content shows a strong (r) correlation (-0.4 to -0.6). This is in contrast with the region semi-annual rain cycle which shows a weaker correlation (0.2 to 0.3).

SYNTHESIS AND CHARACTERIZATION OF STRUCTURAL NANOCOMPOSITE TITANIUM DIOXIDE COPPER-DOPED USING THE IMPREGNATION METHOD La Ode Asmin; La Isa
Spektra: Jurnal Fisika dan Aplikasinya Vol 5 No 1 (2020): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 5 Issue 1, April 2020
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Nanocomposite Titanium Dioxide (TiO2) doped Copper (Cu), Cu-TiO2 is synthesized by the impregnation method. This study aims to determine the effect of adding Cu to the TiO2 structure. The 1, 3, and 5 Cu with% TiO2 dissolved in 50 ml of deionized water, and 3 grams of TiO2 added. The compound is then stirred for 2 hours at 90oC and dried in an oven at 110oC for 30 minutes. Drying samples were calcined at 500oC for 3 hours. Cu-TiO2 nanocomposites were characterized by XRD, SEM-EDX Mapping, and FTIR. The XRD analysis results show that Cu-TiO2 nanocomposite has a high level of crystallinity and has an anatase phase structure. The size of TiO2 crystals decreased with Cu doping and increased from 49.66 nm to 49.68 nm, with an increase in the composition of the doping mass of Cu. The SEM-EDX Mapping results show that all samples tend to clot, and Cu dopants evenly distributed on the surface of TiO2. FTIR analysis explained the presence of hydroxyl ions in the sample marked with the appearance of the absorption peak at 1658.78 cm-1 associated with OH bending of Ti-OH.

THE DESIGN OF DISPLAY DIGITAL DATA INTERFACE CLAMP-METER COMPLEMENTED BY SENSOR GMR (GIANT MAGNETORESISTANCE) Yulkifli Yulkifli; Fitri Afriani; Yohandri Yohandri; Ramli Ramli
Spektra: Jurnal Fisika dan Aplikasinya Vol 5 No 1 (2020): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 5 Issue 1, April 2020
Publisher : Program Studi Fisika Universitas Negeri Jakarta

This 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.

SURFACE MORPHOLOGY OF SPUTTERED TITANIUM-ALUMINUM-NITRIDE COATINGS Esmar Budi; M. Mohd. Razali; A.R. Md. Nizam
Spektra: Jurnal Fisika dan Aplikasinya Vol 5 No 1 (2020): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 5 Issue 1, April 2020
Publisher : Program Studi Fisika Universitas Negeri Jakarta

A study on the surface morphology of sputtered TiAlN coatings is presented. The coatings were deposited by DC magnetron sputtering on tungsten carbide insert tools. The surface morphology was characterized by using Atomic Force Microscopy (AFM), and the surface roughness was indicated by RMS roughness value. It was observed that the TiAlN coating surface morphology was rough as the negative substrate bias and nitrogen flow rate are increased. The evolution of the sputtered TiAlN coatings surface morphology was due to the competition between particle diffusion and re-scattering effect during the sputtering process. At high negative substrate bias and nitrogen flow rate, the re-scattering effect was prominent, leading to the high roughness of the sputtered TiAlN coating surface.

DESIGN OF METAL HEAT CONDUCTIVITY MEASUREMENT USING PROBE METHOD Fitria Hidayanti; Hari Hadi Santoso; Gigih Baskara
Spektra: Jurnal Fisika dan Aplikasinya Vol 5 No 1 (2020): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 5 Issue 1, April 2020
Publisher : Program Studi Fisika Universitas Negeri Jakarta

This study aims to design a tool that can measure the heat conductivity of metals by the Probe method. The design method was used by using a heat-flowed metal beam and the use of an LM35 temperature sensor to measure temperature changes on the probe. We are designing a measurement system based on conduction heat transfer. The metal used in the design is aluminum and carbon steel. For each metal tested, an LM35 temperature sensor is placed on the metal to find out that a temperature change has occurred. The conductivity value can be obtained from the temperature difference between the probe and the metal being tested, the temperature change of the probe, the temperature change of the metal being tested, and the heating time. This value is processed and calculated by the microcontroller into the value of heat conductivity. The measurement results show that the average heat conductivity value is 214.93 W/moC for aluminum and 53.81 W/moC for carbon steel.

DESIGN OF THE POLLUTION GAS CARBON MONOXIDE (CO) MONITORING SYSTEM BASED ON MICROCONTROLLER Erna Kusuma Wati; Fitria Hidayanti; Novi Azman
Spektra: Jurnal Fisika dan Aplikasinya Vol 5 No 1 (2020): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 5 Issue 1, April 2020
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Carbon 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).

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