Article Per Year (5 Year)
p-Index From 2020 - 2025
0.659
P-Index
This Author published in this journals
All Journal BERKALA FISIKA SAINS DAN MATEMATIKA YOUNGSTER PHYSICS JOURNAL JITEK (Jurnal Ilmiah Teknosains) Journal of Physics and Its Applications
Ketut Sofjan Firdausi, Ketut Sofjan
Departemen Fisika, Fakultas Sains Dan Matematika, Universitas Diponegoro, Semarang
Agriculture, Biological Sciences & Forestry Astronomy Civil Engineering, Building, Construction & Architecture Computer Science & IT Earth & Planetary Sciences Materials Science & Nanotechnology Mathematics Mechanical Engineering Physics Veterinary

Published : 24 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 24 Documents
Search

 1   2   3 
KORELASI POLARISASI ELEKTRO-OPTIS DENGAN KOMPOSISI ASAM LEMAK PADA MINYAK ZAITUN SEBAGAI METODE UJI ALTERNATIF MUTU MINYAK GORENG Nurhasanah, W Dewi; Sugito, Heri; Richardina, Very; Azam, Much; Firdausi, Ketut Sofjan
BERKALA FISIKA Vol 22, No 1 (2019): Berkala Fisika Vol. 22 No. 1 Tahun 2019
Publisher : BERKALA FISIKA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (542.01 KB)

Abstract

In this study the quality of olive oil which has been degraded due to heating has been tested using the electro-optical transmission polarization method. The light source used was a laser pointer with λ = 650 nm. The degradation of the quality of olive oil was measured to be based on changes in the electro-optical polarization angle, while changes in the composition of fatty acids were tested using Gas Chromatography and Mass Spectroscopy (GCMS). The results showed that the polarization angle increases in second order polynomial on the increase in voltage and linearly on the heating duration in the sample which showed a decrease in the quality of homogeneous olive oil. Assuming that the polarization change is a linear combination of the main fatty acids from olive oil, it is obtained that C19:2 and C19:0 fatty acids are the most contributing to oil quality, that is, the reduction in oil quality is indicated by increasing polarization which is accompanied by an increase in C19:0 fatty acids and a reduction in C19:2 fatty acids. Whereas specifically for electro-optical polarization, in addition to C19:2 and C19:0 fatty acids, C19:1 also appears which slightly increases polarization by increasing the fatty acid. This method can be developed further for investigation into other vegetable oils, as well as evaluating halal oil due to contamination of lard.Keywords: Electro-optical polarization, olive oil, fatty acid composition, change inpolarization angle
POLARISASI FLUORESENS PADA VIRGIN COCONUT OIL SETELAH MENGALAMI OZONASI Azzahroh, Muffaricha; Sugito, Heri; Richardina, Very; Azam, Much.; Firdausi, Ketut Sofjan
BERKALA FISIKA Vol 22, No 3 (2019): Berkala Fisika Vol. 22 No. 3 Tahun 2019
Publisher : BERKALA FISIKA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (277.063 KB)

Abstract

This study investigates interaction effects between ozone and Virgin Coconut Oil (VCO) on fluorescence polarization. The ozonation time variations carried out on VCO were 30 minutes, 60 minutes and 90 minutes with ozone flow rates of 0.6L / minute. The degradation of VCO quality due to ozonation was determined by measuring changes in the fluorescence polarization angle of the light emitted by the sample, using a green laser pointer with a wavelength of 532 nm. Typical fluorescence polarization characteristics in the range of polarization angle variations from  = 0 to  = 180 are in accordance with the results of previous studies. Increasing the length of ozonation in the sample results in an increase in fluorescence polarization. The average fluorescence polarization in the range 0    180 rises linearly over the duration of ozonation, which indicates that ozone interactions are quite effective in degrading the quality of VCO. The validation results also obtained that the duration of ozonation also increases the amount of free fatty acids, however it needs to be further investigated whether the amount of free fatty acids directly contributes to fluorescence polarization. The study of interaction of ozone in solution in biophysics and also its benefits for skin therapy in medical science are very interesting to be further conducted.Keywords: Fluorescence polarization, Virgin Coconut Oil, polarization angle
REVIEW OF A SIMPLE POWERFUL POLARIZER FOR TESTING OF EDIBLE OIL QUALITY Firdausi, Ketut Sofjan; Rahmawati, Henik
BERKALA FISIKA 2015: Berkala Fisika Vol. 18 No. 4 Tahun 2015
Publisher : BERKALA FISIKA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (282.039 KB)

Abstract

In this paper, we have shown that a simple pair of polarizer can be used to measure natural optical activity in total complex oil (vegetable oil and fats). A similar concept with quantum physics has been discussed to describe briefly the probability in finding a particle within certain region with the change of polarization due to the interaction light with saturated fatty acids. The light source was fluorescence lamp and the experimental condition was kept stable, i.e. constant temperature and constant humidity. The angle of polarization was measured repeatedly until 50 times. Our relative uncertainty measurement has been obtained up to 5% and this is obviously clear to be able to differentiate various different quality of oil. More important result is that ordinary light polarization can be used as powerful test to show various quality level of oils better than recent standard methods. A good prospect has also been obtained for halal level testing. It is found that average value of polarization in lard (pig oil) is relatively higher than the others.Keywords: polarization, oil quality, saturated fatty acid
Pengamatan Efek Magnetooptis Menggunakan Interferometer Fahrurazi, Michelson; Firdausi, Ketut Sofjan; Budi, Wahyu Setia
JURNAL SAINS DAN MATEMATIKA Volume 14 issue 4 Year 2006
Publisher : JURNAL SAINS DAN MATEMATIKA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (391.503 KB)

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
PENINGKATAN EMISI HIDROGEN MELALUI ATOM HELIUM METASTABIL DENGAN METODE LASER INDUCED PLASMA PADA SAMPEL ZIRCALOY Maliki, Maliki; Firdausi, Ketut Sofjan; Budi, Wahyu Setia
JURNAL SAINS DAN MATEMATIKA Volume 17 Issue 2 Year 2009
Publisher : JURNAL SAINS DAN MATEMATIKA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (5352.539 KB)

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.
Role of Saturated Fatty Acid (SFA) for Degradation of Oil Quality Firdausi, Ketut Sofjan
JURNAL SAINS DAN MATEMATIKA Volume 23 Issue 3 Year 2015
Publisher : JURNAL SAINS DAN MATEMATIKA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (297.991 KB)

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)
Natural Polarization and Electrooptics Comparison for Evaluation of Cooking Oil Total Quality Sugito, Heri; Firdausi, Ketut Sofjan
JURNAL SAINS DAN MATEMATIKA Volume 22 Issue 4 Year 2014
Publisher : JURNAL SAINS DAN MATEMATIKA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (384.028 KB)

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.
PENGARUH INDUKSI MEDAN RADIO FREQENCY (RF) PADA DIPOL-DIPOL MOLEKUL AIR Firdausi, Ketut Sofjan; Kamil, Ahmad; Azam, Muchammad
JURNAL SAINS DAN MATEMATIKA Volume 17 Issue 1 Year 2009
Publisher : JURNAL SAINS DAN MATEMATIKA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3722.702 KB)

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 Mubarika, Sofia; Munir, M.; Firdausi, Ketut Sofjan; Widarto, Widarto
JURNAL SAINS DAN MATEMATIKA Volume 14 issue 4 Year 2006
Publisher : JURNAL SAINS DAN MATEMATIKA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (576.971 KB)

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
PENGEMBANGAN KARAKTERISTIK OPTIS PADA LARUTAN PERAK KOLOID MENGGUNAKAN METODE ELEKTRO-OPTIS Tiwiyaningsih, Tiwiyaningsih; Rahmawati, Aidah; Nurhasanah, Wahidatun Dewi; Richardina, Very; Khumaeni, Ali; Firdausi, Ketut Sofjan; Sugito, Heri; Soesanto, Qidir Maulana Binu; Azam, Much
BERKALA FISIKA Vol 23, No 1 (2020): Berkala Fisika
Publisher : BERKALA FISIKA

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (244.635 KB)

Abstract

In this paper we present a new development of optical properties on colloidal silver solutions using electro-optics effect. Samples of silver nanoparticles (NPP) were obtained by ablation method and then diluted in water to obtain various concentrations. To obtain optical characteristics of colloidal silver solutions through the electro-optical effect, the changes in the polarization of light was measured as the sample was applied by high external potential difference. The light source used was laser pointer with  = 650 nm. The results show that the colloidal silver solution shows non-linear active optical properties with increasing concentration and at a concentration of 4.6 ppm maximum natural polarization occurs. In the case of electro-optics, a voltage increase results in electro-optical contributions which correspond to the effects of non-linear polarization due to high electric fields. However, at 8 kV the maximum polarization appears also at a concentration of 4.6 ppm, which is the same as the natural polarization at that concentration. The study of colloidal silver solutions is very interesting to be further developed by electro-optical methods, because challenges and unanswered phenomena can contribute or alternative perspectives in understanding the interaction of light with matter, especially colloidal silver solutions, and the like.
Co-Authors Ahmad Kamil Ali Khumaeni Aziel Nimrod Febriyanto Azzahroh, Muffaricha Ekasari Ekasari Fajri Inayat Henik Rahmawati, Henik Heri Sugito I. Afiefah Izzah Afiefah M. Munir Maliki Maliki Michelson Fahrurazi Much Azam Much. Azam Muchammad Azam, Muchammad Nidia Kharisma Putri Nurhasanah, W Dewi Nurhasanah, Wahidatun Dewi Nyadaniati Simbolon Priyono Priyono Qidir Maulana Rahmawati, Aidah Ririn Widya Septianti S. Suryono Soesanto, Qidir Maulana Binu Sofia Mubarika Haryana Syifa Azahra Tiwiyaningsih, Tiwiyaningsih Ulfa Maftukhah Very Richardina Very Richardina Wahyu Setia Budi Wahyuni Wahyuni Winarno Winarno Zaenul Muhlisin