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PERHITUNGAN INTERAKSI ANTAR NANOPARTIKEL MAGNETIK DAN MAGNETISASI DALAM LAPISAN TIPIS COBALT SAMARIUM MENGGUNAKAN SOFTWARE MATLAB R2015a

Komunikasi Fisika Indonesia Vol 14, No 2 (2017)
Publisher : Universitas Riau

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The calculation of magnetic nanoparticles interaction and magnetization in thin film ofsamarium-cobalt using MATLAB R2015a Software has been performed. The computerconsisted of two program that is program menu and main program. The data entered in theprogram menu are DCD and IRM magnetization values obtained from measurements usingalternating gradient force magnetometer (AGFM). The next step, the main program willcalculate magnetic nanoparticles interaction and magnetization and displays the results ingraphical form. Samarium composition was varied from 10%, 13%, 16%, 22%, 35% and40%. The results show the interaction is positive in the sample, except for samarium 16% ofthe value of a negative interaction (-0.4 Arb.Unit), meaning that from the nature of dipolarinteractions. Sample magnetization value decreases linearly from the composition of 10% to40%, ie 1085,33 emu/cm3 to 226,23 emu/cm3, while the value of coercivity rises with theaddition of samarium composition up to 16%, and maximum values contained in thecomposition of 16%, ie 2052.17 Oersted. Adding of SmCo reaction above 16 at % Smproduced small value of coercivity of the films.

PENENTUAN KONSENTRASI GLUKOSA DAN INSULIN DARAH NORMAL DENGAN METODE SIMULINK

Komunikasi Fisika Indonesia Vol 14, No 2 (2017)
Publisher : Universitas Riau

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A study was conducted with the aim of comparing normal glucose concentrations between modelingresults and the experimental results of 6 normal glucose patients. The patterns of graphs produced ineach of the normal glucose patients vary although each patient is treated equally. The results showedthat the modeling is suitable for experimental data in 17-20 year old women who obtained staticglucose concentration of 73 mg / dl. It can be seen that there are several values of transport rateconstant (K) of the same curve fitting value, that is, on glucose flux (Fg) 80000 mg/dl.s parameter,transport rate of first order (K1) 24.7 s-1, Renal elimination transport rate (K2) 72 s-1, transport rate ofinsulin-glucose (K3) reduction 13,9 s-1, pancreas metabolism transport rate constant (K4) 14,3 s-1.The existence of several parameters that have the same value between modeling and also thisexperiment means that the patient in maintaining the balance of blood plasma glucose in the samedaily, blood plasma glucose is balanced when the efficient pancreatic and kidney organs.

PENGUKURAN INDUKSI MAGNETIK TOTAL DAN IDENTIFIKASI KANDUNGAN ELEMEN ENDAPAN PASIR BESI DI PANTAI BAGIAN SELATAN KOTA PADANG SUMATERA BARAT

Komunikasi Fisika Indonesia Vol 14, No 1 (2017)
Publisher : Universitas Riau

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The measurement of total magnetic induction and identification of elements of iron oxideparticles (consentrate) from Southern Padang City West Sumatera has been done. Thesample was dried under sun ray prior to iron sand separator. X-Ray Fluorescence (XRF) wasused to identify the elements of iron sand only from Bungus and Carolina beach, before andafter iron sand separator process. Total magnetic induction of the sample and solenoid wasmeasured by Pasco magnetic probe 2162. The solenoid was designed for 2500 wonds and 8cm long and diametre of 3 cm. The electric current was applied to the solenoid with the valueof 2-10 A. The total magnetic induction was measured in the direction of horizontal distance,namely 1-5 mm from the edge of the solenoid. The total magnetic induction values increasewhen the electric current increased and decreased when the horizontal distance is increased.

KAJIAN KOMPUTASI POLA GELOMBANG RESONANSI MAGNET INTI (NMR) DENGAN TRANSFORMASI FOURIER

Komunikasi Fisika Indonesia Vol 15, No 1 (2018)
Publisher : Universitas Riau

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Research on nuclear magnetic resonance (NMR) modeling has been done with computational approach. This study aims to determine the shape of signals and spectra of some of the combined nuclear spins. The physical parameters were determined using Fourier transformation equation modeled with the wolfram mathematical software 9.0. The relaxation time of the 1/2 nuclear spin was varied according to the nuclear state of cancer tissue.This produces a cosine wave pattern for the signal at T2 = 0.11 ms. Variations of this in chemical shift (Δ) and J-coupling (J) for modeling were performed in 9 times. The spectrum of one spin is generated at the value of Δ = 0.001 Hz and J = 0 Hz, the spectrum of two spins at Δ = 849,001 Hz and J = 24 Hz. These results can be applied to research interests for the medical world and as reference data for research standards.

STUDI SIFAT MAGNETIK DAN UKURAN PARTIKEL ABU VULKANIK ERUPSI GUNUNG SINABUNG KABUPATEN KARO MENGGUNAKAN PROBE PASCO 2162

Komunikasi Fisika Indonesia Vol 15, No 1 (2018)
Publisher : Universitas Riau

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This study aims to determine the magnetic properties and particle size of the volcanic ash of Sinabung Mount with experiment method. Magnetic properties studied were magnetic degree, magnetic induction magnetic susceptibility, and mass susceptibility of sample. The samples used were volcanic ash taken from the west part of Sinabung, precisely at Gurukinayan village. The ash samples were taken horizontally on the slopes of the Mountain with the amount of 1.5 Kg each point with the number of 10 points (A to J). Separation of concentrate of ash was done using a Neodymium Iron Boron (NdFeB). The magnetic induction of ash and concentrate was measured using a Pasco 2162 Probe using a solenoid is 3 cm in diameter, 10 cm in length and 2000 coil turns. Magnetic induction without a core was measured as a current function (2,4,6,8,10)A and a distance of 1 to 5 mm. The total magnetic induction of ash and concentrate was measured as a current function and the particle sizes was measured using a Light Microscope. The results showed that the greate magnetic degree value at point B of 7.02% and the lowerst level of magnetism is at point J was 1.07%. The largest particle sizes is at point B and the smallest is at point J with particle size of 0.175-0.90 mm. The highest average magnetic susceptibility value for concentrate at point B is 87.32 x 10-3 and the lowest at point F is 20 x 10-3. Based on the mass susceptibility value of the concentrate obtained the volcanic ash of Mount Sinabung is at interval (46–80.000) x 10-8 m3/kg of mass susceptibility value at each location point which contains Ilmenite particles (FeTiO3).

PREPARASI PARTIKEL MAGNETIK DARI PASIR BESI PANTAI BATANG KAPAS SUMATERA BARAT MENGGUNAKAN METODE BALL MILLING

Komunikasi Fisika Indonesia Vol 15, No 2 (2018)
Publisher : Universitas Riau

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Preparation of micro magnetic particle and its magnetic propertis from iron sand beach of Batang Kapas west Sumatera using Ball Milling method has been done. Prior to the Ball Milling process, the samples were processed by iron sand separator (ISS) in order to separate between magnetic particles and non magnetic one. Next, the concentrates from ISS were crushed by Ball Milling method  as a function of time namely 20, 40, and 60 hours. For separation between magnetic particles and non magnetic one, then NdFeB magnet was utilized. The results showed that the magnetic degree of the sample is about 0,5%. Measurements of magnetic induction solenoids were carried out using a Magnetic Probe Pasco PS -2162 as a function of current (2, 4, 6, 8 and 10) A and a  functions of distance (1, 2, 3, 4, and 5) mm. Then the total magnetic induction of the solenoid (solenoid with sample core and concentrate) was measured as a function of an electric current for a fixed distance of 1 mm. The calculation results showed that magnetic susceptibility and mass susceptibility increase with Ball Milling time from (3376,400-7765,130). This value is within the interval of 46-80000 which is the interval of Ilmenite mineral (FeTiO3; Antiferromagnetik). The increase in magnetic susceptibility and mass susceptibility of samples processed by Ball Milling is thought to be due to the increasing number of magnetic particles in the sample.

ANALOG COMPUTER FOR STUDYING DIATOMIC MOLECULAR SPECTRA IN TERAHERTZ FREQUENCY

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

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This paper introduces a harmonic oscillator model for rovibronic terahertz spectrum of a model of a rigid diatomic rotor with some control parameters. The model shows a study of rotationally-resolved terahertz band spectra of the vibrational transition in diatomic molecules. THz radiation absorption is used as a closed-form system known as the analog computer dynamics mode. The optical terahertz region spectrum of the diatomic molecule consists of a series of lines. Their separations are not exactly constant. A diatomic molecule is not truly a rigid rotator, because it simultaneously vibrates with a small amplitude. Due to quantized vibrational and rotational energy levels and the selection rules, allowed transitions result in a highly ordered spectrum consisting of a P branch separated by a central gap. Adjacent spectral lines are separated by a spacing of 2B, and since line intensities depend on Boltzmann factor for thermal population and quantum number J, each branch monotonically increases and decreases. As temperature increases, more lines are observed, and line intensities decrease due to the population being spread over more rotational levels. Interactivity research also involves on effects of the fundamental vibrational frequency, rotational constant B and temperature included line width on the observed spectrum.

EDDY CURRENT SENSOR BERBASIS FLAT COIL FR4 UNTUK MENENTUKAN KETEBALAN PELAT LOGAM NON MAGNETIK AL

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

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Abstrak Sensor arus eddy (eddy current) digunakan untuk pengukuran ketebalan logam khususnya logam non magnetik seperti alumunium.  Penelitian ini telah mengembangkan sensor eddy current berbahan PCB (printed circuit board) jenis FR4 yang memiliki ketebalan lapisan tembaga 35micron. Prototipe yang dihasilkan mempergunakan koil sensor dengan jumlah gulungan (n) 30 lilitan, diameter (Æ) 30mm, lebar dan jarak antar koil, (dkoil) 0,254mm dan tahanan (Rkoil) sebesar 4,26Ω. Respon sensor ketebalan pelat logam terhadap bahan uji dievaluasi dengan memberikan eksitasi frekuensi tunggal 700Khz, 1MHz dan 1.33MHz. Rangkaian ketebalan pelat telah mempergunakan rangkaian pengunci fasa (phase locked loop) dan mampu mengukur variasi ketebalan  mulai 0,2 mm sampai 2 mm, sementara jarak antara sensor dengan logam uji dijaga konstan 2 mm. Hasil pengukuran memberikan respon kurva U(t) dalam hubungan Kata-kata kunci:sensor eddy current, PCB FR4, material non magnetik, ketebalan logam, rangkaian phase locked loop Abstract Eddy current sensor is used to measure the thickness of metals, especially non-magnetic metals such as aluminum. This research has developed eddy current sensor made from PCB (printed circuit board) type FR4 which has 35micron copper layer thickness. The developed prototype uses a designed coil sensor with the number of winding (n) 30 turn, diameter () 30mm, width and distance between coils, (dkoil) 0.254 mm and coil resistance (Rkoil) of 4.26 Ω. The sensor response to the test material was evaluated by giving a single frequency excitation of 700 Khz, 1 MHz and 1.33 MHz. The plate thickness electronics has used a phase locked loop circuit and is capable to measure the thickness variations from 0.2 mm up to 2 mm, while the distance between the sensor coil and the test object was kept constant at 2 mm. The measurement results give the U (t) curve response in the exponential relationship. Keywords: eddy current sensor, PCB FR4, nonmagnetic material, thickness, phase locked loop circuit