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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

Arjuna Subject : -

Articles 260 Documents

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PENGARUH TEGANGAN TABUNG (KV) TERHADAP KUALITAS CITRA RADIOGRAFI PESAWAT SINAR-X DIGITAL RADIOGRAPHY (DR) PADA PHANTOM ABDOMEN Sriwahyuni Sriwahyuni
Spektra: Jurnal Fisika dan Aplikasinya Vol 2 No 2 (2017): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 2 Nomor 2, Agustus 2017
Publisher : Program Studi Fisika Universitas Negeri Jakarta

The measurement of image quality ofÃ‚ Digital Radiography (DR) with using the abdomen phantom. Image take with low kV to high kV for 10 times exposure. Image processing is done using the image application. The resulting radiograph image is analyzed by FFT analysis, Histogram and Gaussian Filter. In the FFT analysis the radiographic image tends to differ according to the tube voltage variation of 40 kV to 85 kV. In the radiographic image histogram analysis, including the imperfect image category because the distribution of pixel distribution is not yet complete in the gray scale area for all exposure variations. In the analysis using Gaussian filters the resulting radiographic image tends to be the same so that although using low kV and high kV the image will be the same. The use of Gaussian filters can help reduce the use of high kV on abdominal examination and reduce exposure to radiation dose. Keywords: Digital Radiography, Image Quality, Fourier Transform Filter, Gaussian Filter, Histogram.

PENGARUH PANJANG STACK SELUBUNG KABEL TERHADAP PERUBAHAN SUHU PADA SISTEM PENDINGIN TERMOAKUSTIK Indah Kharismawati; Hanif Rafika Putri
Spektra: Jurnal Fisika dan Aplikasinya Vol 2 No 2 (2017): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 2 Nomor 2, Agustus 2017
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Research on environmentally friendly thermo-acoustic coolants uses a heat exchanger from the cable sheath material. The resonator tube used in the thermoelectric cooler is a 5.25 cm diameter PVC (polyvinyl chloride) tube with a length of 87 cm. Variations in stack lengths of 4cm, 5cm, 6cm, 7cm, and 8cm were performed to obtain results on thermoelectric coolers. Results are available on the use of stack length 4 cm high temperature 21.6 oC from the initial temperature), the stack length 5 cm high temperature 21.1 oC from the initial temperature (room temperature), the stack length of 6 cm resulted in a maximum temperature drop of 22.6 oC from the initial temperature (room temperature), the stack length of 7 cm resulted in a maximum temperature drop of 22.0 oC from the initial temperature (room temperature), while the stack length of 8 cm resulted in a decrease in temperature maximum of 23.3 oC from the initial temperature (room temperature). Keywords: Thermoacoustic, stack, temperature changes.

DISTRIBUSI SPASIAL DENSITAS CAKRAM BERUKURAN SAMA DALAM PEMODELAN PEMBENTUKAN ASTEROID Sparisoma Viridi; Budi Dermawan
Spektra: Jurnal Fisika dan Aplikasinya Vol 2 No 2 (2017): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 2 Nomor 2, Agustus 2017
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Several two-dimension particles in the form of a disk, which only interact through gravitational force and normal force, are simulated. Assumed that there are only two values of particle density (same diameter but different mass). Simulation are conducted until particles position are slightly constant. It is obtained that density is varied radially, decreasing with an increase of radial position, and nearly isotropic angularly in final condition. It has been simulated N = 64 particles with mass ratio mA/mB = 0.25 for 944 s simulation time. Keywords: asteroid forming, granular material, density distribution, binary mixture

ANALISIS PENGARUH SUHU MINYAK KELAPA SAWIT (CPO) TERHADAP NILAI TAHANAN TERMAL MEMPERGUNAKAN PEMODELAN KURVA I(V) ISOTERMAL SENSOR PTC Dellia Yulita; Lazuardi Umar
Spektra: Jurnal Fisika dan Aplikasinya Vol 2 No 2 (2017): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 2 Nomor 2, Agustus 2017
Publisher : Program Studi Fisika Universitas Negeri Jakarta

PTC level sensor for overfill protection works based on the thermal resistance (Rw). The sensor cannot identify high-temperature fluid in the container and determine the pump switching status Ã¢â‚¬Å“ONÃ¢â‚¬Â and Ã¢â‚¬Å“OFFÃ¢â‚¬Â. This is due to the influence of the medium temperature on the Rw. Analysis is performed by observing the Rw value of crude palm oil (CPO) as a result of the storage temperature. The Rw value was obtained from the modeling of I (U) sensor curve of EPCOS B59050D1100 with temperature variations ranging from 20Ã‚Â°C to 80Ã‚Â°C. The modeled area is then determined using the isothermal curve and is resulted Rw value of 110.2K/W. The ambient temperature influence on Rw can be modeled after polynomial equation. Compare to the previous air measurement, the thermal resistance in CPO has 62.6% vary than in the air. This value can be used to determine the position of the level sensor switch safely. Keywords: level sensors, PTC, thermal resistance, CPO, isothermal

KARAKTERISASI SENSOR PHOTODIODA, DS18B20, DAN KONDUKTIVITAS PADA RANCANG BANGUN SISTEM DETEKSI KEKERUHAN DAN JUMLAH ZAT PADAT TERLARUT DALAM AIR Zulfiah Ayu Kurnia Sari; Handjoko Permana; Widyaningrum Indrasari
Spektra: Jurnal Fisika dan Aplikasinya Vol 2 No 2 (2017): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 2 Nomor 2, Agustus 2017
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Abstract Drinking water worth consumption are those that should be odorless, tasteless, clean, the temperatures preferably below air temperature, and low amounts of dissolved solids. On this turbidity and total dissolved solid water system is required some sensor devices. The accuracy of the sensor is an important thing to support the effectiveness of the system. In this research, the calibration of ds18b20 sensor as temperature detector, photodiode sensor as turbidity detector, and conductivity sensor as a detector of dissolved solid (TDS) in water and using Arduino as a microcontroller. The characterization is done by comparing the sensor output with laboratory test equipment. The result of characterization means that each measurement sensor has a variation error that is photodiode sensor with relative error 3.13%, sensor ds18b20 1.77%, and conductivity sensor 2.42%. Keywords: temperature, turbidity, TDS, Arduino.

INVESTIGASI PEMBENTUKKAN IKATAN Zn-O RODS DI ATAS PERMUKAAN MIKROKANTILEVER DENGAN UJI KARAKTERISASI FTIR Mia Yuliana Frestika; Rina Dewi Mayasari; Masmui Masmui; Agustanhakri Agustanhakri; R. Ibrahim Purawiardi; Yuliasari Yuliasari; Ahmad Novi Muslimin; Muhammad Dani; Agus Setyo Budi; Ratno Nuryadi
Spektra: Jurnal Fisika dan Aplikasinya Vol 2 No 2 (2017): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 2 Nomor 2, Agustus 2017
Publisher : Program Studi Fisika Universitas Negeri Jakarta

In this work, ZnO (Zinc Oxide) rods, which is a sensitive material for gas detection, are grown on a microcantilever surface by hydrothermal technique. Synthesis of ZnO rods consists of two processes, i.e., a formation of seed layer using Zinc Acetate Dihydrate by a dip-coating and a growth of the ZnO rods using Zinc-Nitrate-Tetrahydrate at a temperature 95Ã‚Â°C for time variations of 2 hours, 4 hours and 6 hours. Drying condition for both seed layer and growth of ZnO rods was done at a temperature of 120 oC for 2 hours. The ZnO rods were then characterized by Fourier Transform Infrared (FTIR) in order to investigate the formation of Zn-O bond. The characterization results indicate that the metal oxide correlation is shown in the wavenumber spectrum of 540 cm-1 for a sample with 2-hour growth time, while the wavenumber spectrum of 548 cm-1 and 547 cm-1 for the growth time of ZnO rods for 4 hours and 6 hours. Wavenumber spectrum approximately at 540-548 cm-1 is predicted to be the absorption of the formation of a Zn-O bond. Keyword: Microcantilever, ZnO rods, dip-coating, hydrothermal, growth time dependent.

PENGARUH SUBSTITUSI ION Ti-Zn TERHADAP SIFAT KEMAGNETAN dan SIFAT PENYERAPAN GELOMBANG ELEKTROMAGNETIK MATERIAL SISTEM BaFe12-xTix/2Znx/2O19 Nenni Nenni; Mutia Delina; Wisnu Ari Adi; Yana Taryana
Spektra: Jurnal Fisika dan Aplikasinya Vol 2 No 2 (2017): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 2 Nomor 2, Agustus 2017
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Substitution of Ti+4 and Zn+2 ions on magnetic material BaFe12-xTix/2Znx/2O19 (x = 0 and 2) using the wet milling method has been performed. This research was conducted to get information the influence of Ti-Zn substitution on magnetic properties and its absorption. The magnetic material BaFe12-xTix/2Znx/2O19 is synthesized from a mixture of oxide materials, BaCO3, Fe2O3, TiO2 and ZnO. The mixture was milled for 5 hours, dried at 1000C then sintered at 10000C for 5 hours. The refinement result of the X-ray diffraction pattern shows that the sample has single phase BaFe12O19 with doping concentration of x = 0 and 2. The hysteresis curve shows that coercivity field value decreased in the sample with doping concentration of x = 2. The result of electromagnetic wave absorption shows that the substituted sample with Ti+4 and Zn+2 ions (doping concentration x = 2) has the highest absorption peak at a frequency of 11,2 GHz with reflection loss value (RL) of -24,3 dB. Electromagnetic wave absorption reaches 94% with sample thickness is about 1,0 mm. Therefore, the magnetic material BaFe12-xTix/2Znx/2O19 (x = 2) can be used for application of the electromagnetic wave absorber. Keywords: Substitution, BaFe12-xTix/2Znx/2O19, wet milling, reflection loss, electromagnetic wave absorber.

ANALYSIS OF PROCIMATE ON THE CHARCOAL BRICKET AGRICULTURAL WASTE Leni Rumiyanti; Annisa Irnanda; Yusup Hendronursito
Spektra: Jurnal Fisika dan Aplikasinya Vol 3 No 1 (2018): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 3 Issue 1, April 2018
Publisher : Program Studi Fisika Universitas Negeri Jakarta

AbstractResearch has been conducted to know the best and worst quality of charcoal briquettes from agricultural wastes based on their proximate content. These agrarian wastes are rice husk, sugarcane baggage, cassava peel, corncob, and coconut shell. The research method is pyrolysis carbonization at 700-800 oC for 45 min and proximate analysis with techniques that suitable Indonesian National Standard (SNI) for testing of moisture, ash, volatile matter, and fixed carbon content. The research result showed that the best charcoal briquettes quality is cassava peel because it has the lowest water content of 0.3833% and the lowest ash content of 0.8452%. While the worst charcoal briquettes quality is corncob because it has the highest water content of 2,412% and the lowest fixed carbon of 71,442%.Keywords: charcoal briquettes, agricultural wastes, proximate analysis.

IMAGING OF 3-D SEISMIC TOMOGRAPHY FOR INTERNAL STRUCTURE UNDER THE MOUNTAIN MERAPI USING THE LOTOS-10 SOFTWARE Ayu Wita Sari; Gede Bayu Suparta
Spektra: Jurnal Fisika dan Aplikasinya Vol 3 No 2 (2018): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 3 Issue 2, August 2018
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Abstrak Telah dilakukan penelitian pencitraan tomografi seismik 3D untuk stuktur internal di bawah Gunung Merapi dengan empat stasiun pencatat gempa dan gempa vulkanik sebagai sumber sinar gelombang. Penelitian ini menggunakan perangkat LOTOS-10 (Local Tomography Software 10) untuk inversi tomografi seismik 3D. Karakteristik medium bawah Gunung Merapi dapat digambarkan oleh parameter fisis seperti kecepatan gelombang primer dan sekunder. Hasil pengolahan data seismograf menunjukkan metoda tomografi seismik dapat mengungkap struktur bawah permukaan Gunung Merapi melalui distribusi anomali deviasi kecepatan dan Vp/Vs ratio. Kualitas citra yang dihasilkan dengan menggunakan gelombang primer lebih jelas resolusinya dan waktu yang digunakan lebih efesien, sehingga dapat digunakan sebagai informasi mitigasi bencana sebelum gempa erupsi terjadi. Daerah anomali negatif yang diperoleh terletak di bawah puncak Gunung Merapi pada kedalaman 3 - 5 km mempunyai karakter fisis yaitu zona lemah, kurang kompak, panas dan heterogen. Daerah anomali tersebut dapat diinterpretasikan sebagai keberadaan zona materi panas yang berasosiasi dengan sisa dapur magma dangkal. Kata-kata kunci: Gunung api Merapi, sifat fisis, tomografi seismic, lotos-10. Abstract 3D seismic tomography imaging research conducted for internal structures under Merapi Volcano with four earthquake recording and volcanic earthquake stations as a source of wave rays. This study used LOTOS-10 (Local Tomography Software 10) for 3D seismic tomography inversion. Characteristics of the medium under Merapi Volcano described by physical parameters such as primary and secondary wave velocities. The result of seismograph data processing shows seismic tomography method can reveal the subsurface structure of the Merapi Volcano through the distribution of deviation anomaly speed and Vp / Vs ratio. Image quality generated by using primary wave more clearly the resolution and time used more efficient, so that can be used as disaster mitigation information before earthquake eruption happened. The negative anomaly area obtained under the peak of Merapi Volcano at a depth of 3 - 5 km has the physical characteristics of weak, less compact, hot and heterogeneous zones. The anomalous region can interpret as the existence of a zone of heat material associated with the rest of the shallow magma kitchen. Keywords: Mount of Merapi, physical character, Seismic of Tomography, lotos-10.

DESAIN DAN PEMBUATAN PROTOTIPE PULSE ELECTROMAGNETIC THERAPY (PEMFT) UNTUK STUDI BIOELEKTROMAGNETIK Umiatin Umiatin; Tesa Apriyanti; Sastra Kusuma Wijaya
Spektra: Jurnal Fisika dan Aplikasinya Vol 2 No 3 (2017): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 2 Nomor 3, Desember 2017
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Abstrak Pulse Electromagnetic Therapy (PEMFt) atau lebih dikenal dengan PEMF merupakan salah satu modalitas yang disetujui oleh Food and Drug Administration (FDA) untuk membantu proses penyembuhan fraktur tulang non union (gagal sambung). Saat ini alat PEMF yang dijual dengan harga yang tidak murah, memiliki parameter fisis yang bervariasi sehingga dalam penggunaannya menghasilkan efektivitas beragam dan terkadang menimbulkan kontraindikasi. Dalam penelitian ini telah dilakukan desain, pembuatan dan uji coba prototipe alat PEMF menggunakan Arduino dan Labview. Tujuan dari penelitian ini adalah mendapatkan alat PEMF yang dapat digunakan dalam penelitian bioloektromagnetik. Penelitian dilakukan dalam tiga tahap yaitu tahap desain dan perancangan perangkat keras, desain dan perancangan perangkat lunak dan tahap ketiga adalah ujicoba alat PEMF untuk penelitian fraktur tulang menggunakan hewan coba tikus. Pada tahap pertama dibuat kumparan Helmholtz dengan diameter 40 cm, jumlah lilitan 500, menggunakan kawat tembaga 0.7 mm. Karakterisasi medan magnet yang dihasilkan dengan menggunakan Gaussmeter IDR 324 pada sumbu x, pada tegangan 18 V dan arus sebesar 0.28 A, menghasilkan medan magnet homogen sebesar 0.4 mT. Pada tahap kedua dilakukan pembuatan kode program alat PEMF menggunakan Labview dan mikro kontroler Arduino Uno. Parameter fisis PEMF yang dikendalikan adalah waveform, frekuensi, duty cycle, burst time dan exposure time. Pembuatan antar muka dan pengolahan data dilakukan menggunakan program LabVIEW. Pada tahap ketiga telah dilakukan ujicoba prototipe alat PEMF yang dibuat untuk studi pada hewan coba yaitu tikus Spraque Dawley selama 28 hari. Kata-kata kunci: Kumparan Helmholtz, PEMF, Bioelektromagnetik, Arduino Uno, LabVIEW. Abstract Pulse Electromagnetic Therapy (PEMFt) or better known as PEMF is one of the modalities approved by the Food and Drug Administration (FDA) to assist the healing process of non union bone fractures (failed connect). Currently PEMF equipment sold at a price that is not cheap, has a varying physical parameters so that in its use produce various effectiveness and sometimes contraindicated. In this research have been done design, manufacture and test prototype of PEMF tool using Arduino and Labview. The purpose of this research is to obtain PEMF tool which can be used in bioloectromagnetic research. The research was conducted in three stages, namely design and hardware design, design and software design, and the third step is PEMF testing for bone fracture research using mouse rats. In the first stage is made Helmholtz coil with a diameter of 40 cm, the number of windings 500, using 0.7 mm copper wire. The magnetic field characterization generated using Gaussmeter IDR 324 on the x axis, at a voltage of 18 V and a current of 0.28 A, produces a homogeneous magnetic field of 0.4 mT. In the second stage, the programming of PEMF tools was made using Labview and Arduino Uno micro controller. The controlled PEMF physical parameters are waveform, frequency, duty cycle, burst time and exposure time. Interface creation and data processing is done using LabVIEW program. In the third phase, a prototype PEMF test was made for a study of experimental animals of Spraque Dawley mice for 28 days. Keywords: Helmholtz coil, PEMF, Bioelectromagnetic, Arduino Uno, LabVIEW.

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