Ketut Sofjan Firdausi, Ketut Sofjan
Departemen Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro, Semarang

Published : 16 Documents
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PENINGKATAN EMISI HIDROGEN MELALUI ATOM HELIUM METASTABIL DENGAN METODE LASER INDUCED PLASMA PADA SAMPEL ZIRCALOY

JURNAL SAINS DAN MATEMATIKA Volume 17 Issue 2 Year 2009
Publisher : JURNAL SAINS DAN MATEMATIKA

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Abstract

ABSTRACT-Telah dilakukan  analisis  unsur  hidrogen  dari sampel  zircoloy  dan  sampel  batu  hitam melalui  pembangkitan  plasma  gelombang  kejut menggunakan laser Nd YAG (1064 nm, 8 ns, 68 mJ)  pada tekanan  rendah  dengan  mengalirkan  gas helium dan gas nitrogen sebagai  gas penyangga  di  dalam  ruang sampel.  Penelitian  dilakukan  untuk menunjukkan  pengaruh  atom  helium metastabil  pada  peningkatan  emisi hidrogen. Pengaruh atom  helium  metastabil pada  peningkatan emisi  hidrogen  ditunjukkan  dengan membandingkan  penggrmaan  gas  nitrogen  dan  gas  helium sebagai  gas  penyangga  pada  tekanan  2 torr dan  5 torr. Dari penelitian,  intensitas  emisi  hidrogen  menggunakan  gas  nitrogen  pada  tekanan  2 torr dan  gas  helium pada  5  torr untuk  sampel  zircaloy masing-masing  diperoleh  sebesar  317,0  cacah/detik  dan  4370,0  cacah/detik, sedangkan  pada  sampel  batu  hitam masing-masing  diperoleh  sebesar  297,6 cacah/detik  dan 694,0 cacah/detik. Hasil  ini  menunjukkan  atom helium metastabil  yang dihasilkan melalui helium sebagai  gas penyangga berpengaruh  terhadap  peningkatan  emisi  hidrogen  pada  sampel  zircaloy dan  batu  hitam. Kata  kunci : sampel zircaloy, sampel batu hitam, laser induced plasma, atom helium metastabil,  emisi hidrogen dan emisi helium.

Pengamatan Efek Magnetooptis Menggunakan Interferometer

JURNAL SAINS DAN MATEMATIKA Volume 14 issue 4 Year 2006
Publisher : JURNAL SAINS DAN MATEMATIKA

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Abstract

ABSTRACT---The magnetooptic effect of transparency material such as aquarium glass, acrylic, and micro slide has been studied using Michelson Interferometer. The change of refractive index to magnetic field B is obtained by placement of samples in a coil applied on altered field 0-0,2 T. Results of interferometer test show that change of refractive index is linearly dependent on B for acrylic and slide. However, for aquarium glass, it is on B2 dependency. This result is agreement to previous experiment that the structure of acrylic and slide is formed more regular as B applied. Keywords: Magnetooptic effect, refraction index, interferometer

Natural Polarization and Electrooptics Comparison for Evaluation of Cooking Oil Total Quality

JURNAL SAINS DAN MATEMATIKA Volume 22 Issue 4 Year 2014
Publisher : JURNAL SAINS DAN MATEMATIKA

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Abstract

In this study, the phenomena of natural polarization and electrooptics effect have been compared as alternative methods for evaluation of vegetable oil quality. The sample used in the experiment was various vegetable oils. The change of light polarization was measured using a pair of polarizer for natural polarization and in case of electrooptics with addition of induced external electric field through DC high voltage. The result has shown that both methods are able to indicate the level of various oil quality. The natural polarization is very useful for preliminary test of oil quality. In the other hand, the electrooptics has a good prospect as single physical indicator for vegetable oil quality.

Mapping Various Cooking Oil using Fluorescence Polarization

Journal of Physics and Its Applications Vol 1, No 1 (2018): November 2018
Publisher : Journal of Physics and Its Applications

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Abstract

In this report we have succeeded to map various cooking oils using change of fluorescence polarization. Various cooking oils consisted of several vegetables oils and animal oils (chicken oil and lard) were used in the experiment, and some oils were measured in two different times. The change of polarization angle &tetha; was measured as the difference between linear polarized green pointer laser as incoming light and fluorescence light using a pair of polarizers. The direct measurement of fluorescence polarization gives a new unique result of critical polarizer’s angle φc that can group vegetable cooking oils into group 1 (at φc = 10o for VCO, olive, and soybean), group 2 (at φc = 20o for palm, corn and rice bran), group 3 (at φc = 30o for sunflower and canola), and also animals cooking oils into group 4 (at φc = 20o for chicken oil), and group 5 (at φc = 40o for lard). Mostly cooking oils can be distinguished using modified maps. The large difference φc and &tetha; of lard from vegetable oils provides an advantage to develop for testing halal oil due to lard contamination. The capability of this method has benefits, at least, as a complement and simple method in comparison to other expensive sophisticated instruments such as fluorescence spectroscopy or GCMS methods with their derivation’s instruments.

PENGARUH INDUKSI MEDAN RADIO FREQENCY (RF) PADA DIPOL-DIPOL MOLEKUL AIR

JURNAL SAINS DAN MATEMATIKA Volume 17 Issue 1 Year 2009
Publisher : JURNAL SAINS DAN MATEMATIKA

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Abstract

ABSTRACT-The non-linear optical property of rotary power of light polarization in water has been develop using the Radio-Freguency field (RF-Field). The RF-Field used in the experiment is produced by RF generator, and it supplies the frequency in the range betwen 6,04 to 14,56 MHz which then applies to the samples. The source of light with 632,8 nm-wavelength and 532 nm-wavelength are used to observe the change of range polarization of the light after it passes througt the samples.  Three modes of the direction of the electric field of light are chosen 0o (E//) (E of light is parallel to E of RF-Field), and 90o (E ) (E of light is perpendicular to E of the RF-Field) in order to determinate the optimal change of the angle of the polarization β. The values of β is measured as a function of RF-Field,  , where ωRF is the angular frequency of RF-Field and  BRF is the magnitude of magnetic field measured in the center of the coil which is assumed to be homogeny in the circumstances of the samples. The results of the experiment show that the degrees of change of the polarization direction, η is largest at the E3 mode. It shows also that at small wavelength of light we obtain the larger η, which is indicated the higher frequency of liglt will more induce the dipoles of molecules of the samples. Keywords:  non- linear optics, polarization angle, rotary power

Learning Vector Quantization Pada Pengenalan Pola Tandatangan

JURNAL SAINS DAN MATEMATIKA Volume 14 issue 4 Year 2006
Publisher : JURNAL SAINS DAN MATEMATIKA

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Abstract

ABSTRACT---In this paper, we analyze and compute distribution of thermal neutron flux in core of Kartini’s Reactor using “Swadaya” detector, both for axial (function of z) and radial (function r) direction. First, “Swadaya” detector is calibrated by activation plate method, which the output from detector is current. The result of calibration is thermal neutron flux (ф) dependent on current (I) that can be written as ф = 4,57x1020I - 2,74x1011. Distribution for neutron thermal flux for axial direction and radial direction respectively Ф = 5,10 x 1012 + 5,99 x 1013 and ф = 1.08 x 1012 + 1,00 x 103 which in reactor core ф has largest value in center position for radial direction.   Keywords: flux neutron distribution, nucleus reactor, Swadaya detector

Role of Saturated Fatty Acid (SFA) for Degradation of Oil Quality

JURNAL SAINS DAN MATEMATIKA Volume 23 Issue 3 Year 2015
Publisher : JURNAL SAINS DAN MATEMATIKA

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Abstract

In this study, the phenomena of natural polarization has been used as a preliminary test of vegetable oil quality. The formation of saturated fatty Acid (SFA) has been studied as a most responsible parameter for degradation of oil quality related to its expired limitation. The Oil quality was indicated by change of light polarization, and was measured using pair of polarizer-analyser. The result shows that the change of polarization can be used to indicate oil quality level related to its expiration date. This method also shows predicted SFA formation and apparently it is relative more powerful than standard parameters such as free fatty acid (FFA) test and peroxide value (PV) test. For future, this method has provided good prospect to evaluate the existence of the halal level of oil due to lard (pig oil). Keywords: natural polarization, vegetable oil quality, saturated fatty acid (SFA)

ANALISIS KUALITAS MINYAK GORENG BERDASARKAN NILAI GRADIEN PERUBAHAN SUDUT POLARISASI MENGGUNAKAN METODE ELEKTROOPTIS

YOUNGSTER PHYSICS JOURNAL Vol 5, No 2 (2016): Youngster Physics Journal April 2016
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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Abstract

Palm cooking oil quality testing has been done using natural polarization and electro-optics. Tests conducted to determine the quality of oil based active optical properties of the oil. The addition of external electric field aims to get the value of the polarization angle changes each brand oil. Oil samples were tested in the form of palm oil with a variety of brand new and has ditreatmen oil for frying foodstuffs. Test parameters after the addition of external electric field gradient that is of value elektrooptis. The test results, samples of oil to the value of large polarization angle gradient changes indicated have relatively low quality. Instead gradient small polarization angle, indicating high quality oil. Elektrooptis smallest gradient value of 0,51o/ kV, while the largest gradient value is 0,68o / kV. Keywords: polarization, elektrooptis, oil quality

PENGUKURAN PERUBAHAN SUDUT POLARISASI OLEH FLUORESENSI PADA SAMPEL MINYAK ZAITUN

YOUNGSTER PHYSICS JOURNAL Vol 5, No 4 (2016): Youngster Physics Journal Oktober 2016
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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Abstract

The aim of this research is to show how the quality difference of cooking oil affect polarization angle changes of fluorescence. The fluorescence could be usefull to identify quality of matter according to colour changes. In this research, to identify fluoresence polarization changes edible and expired olive oil used as sample with different expired date. To produce fluorescence, a green laser with wavelength 532 nm pass by polarizer and produce polarized light. Analizer sets perpendicular to polarization plane. The result show that quality difference affect the fluorescence polarization changes. The worst quality of oil the higher polarization changes. Smallest polarization changes we get in the best quality edible olive oil as 50,90 and 61,60 for the expired one.

PENGUKURAN PERUBAHAN SUDUT POLARISASI PADA KOLESTEROL SEBAGAI KOREKSI PADA MINYAK SAWIT

YOUNGSTER PHYSICS JOURNAL Vol 5, No 4 (2016): Youngster Physics Journal Oktober 2016
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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Abstract

This research aims to determine the relation between changes of polarization angle and increased levels of cholesterol and triglycerides on palm oil (expired palm oil, edible palm oil) to the change of polarization angle. Samples were placed on a polarimeter with a light source of 100 W incandescent lamp. The results showed that the increase in the cholesterol is directly proportional to the change in polarization angle. The greater increase of cholesterol levels result in the greater of the change of polarization angles that showed in the non linier graph. The value of the change of polarization angle in expired palm oil, edible palm oil are θ cholesterol = 0,26⁰; 0,25⁰ for cholesterol and θ triglycerides = 1,19⁰ ; 0,6⁰ for triglycerides, respectively. So it can be seen that the increase of each change of polarization angle of triglyceride which is the difference of θ total with θ cholesterol are affected by the increase of cholesterol levels in the cooking oils. The volatile property of the solvent and the less stabil environment temperature also could affected the result of the study.