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All Journal BERKALA FISIKA Sainstek : Jurnal Sains dan Teknologi
K. Sofjan Firdausi
Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro Semarang
Computer Science & IT Physics Other

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Rancang Bangun Spektroskopi FTIR (Fourier Transform Infrared) untuk Penentuan Kualitas Susu Sapi Endro Suseno, Jatmiko; Firdausi, K. Sofjan
BERKALA FISIKA Vol 11, No 1 (2008): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

A Fourier Transform Infrared spectroscopy instrument has beed developed in the range middle infrared. The important instrument in this research is to make interferogram using He-Ne Laser based on Michelson interferometer. The result indicates that the interferogram seems work well and should give some spectra in the range of middle infrared frequencies. Key words: FTIR, interferogram, spectroscopy
Penentuan Koefisien Linier Elektro Optis Pada Aquades dan Air Suling Menggunakan Gelombang RF Jatwiyono, Lilik Eko; Sugito, Heri; Firdausi, K. Sofjan
BERKALA FISIKA Vol 10, No 4 (2007): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

The coefficients of electrooptics for water and refinery water in RF field have been determined. The RF frequency range used in the research is 6,04 MHz to 11 MHz. Two different light beam (532 nm and 632,8 nm) have been used to measure the change of light polarization after transmitted the samples. The result indicates that the linear and quadratic electro optic coefficients appear in the range of frequency-field. The refinery water has greater value of linear electro optic coefficient than aquades. It is also obtained that the greatest change of polarization angle take place when using the green laser in the field’s position of upright against the RF frequency field and polarization angle of 900.   Keywords: RF field, polarization angle, linear electro optic coefficient.
Penentuan Kandungan Unsur Krom dalam Limbah Tekstil dengan Metode Analisis Pengaktifan Neutron Khaerani, Nina; Azam, Much.; Firdausi, K. Sofjan; Soeleman, Soeleman
BERKALA FISIKA Vol 10, No 1 (2007): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

A determination of chromium which consisted in textile cesspool one of the company of textile residing in Ungaran using neutron activation analysis method.The sample has been threated in the form of sediment sample and liquid sample. The sample then an irradiated by Lazy Susan irradiation facility at Kartini reactor for six hours and then  the counting is done by HPGe detector for 300 seconds. The qualitative results shown that samples contents Cr-51. The quantitatively sediment sample chromium element rate equal to 491. 67 ppm and liquid sample chromium element rate equal  to 0.011  ppm Key words: Neutron Activation Analysis, irradiation.
STUDI SIFAT ELEKTROOPTIS PADA KACA AKUARIUM, KACA PREPARAT, DAN AKRILIK Nila Kusuma, Anis; Firdausi, K. Sofjan; Setia Budi, Wahyu
BERKALA FISIKA Vol 9, No 2 (2006): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

The properties of electrooptics of transparency media such as aquarium glass, micro slides, and acrylic have been studied. To obtained the change of refractive index (Dn) of materials against external static electric field (E), the samples are placed in two parallel plates applied by potential different of  0 – 104 V. The maximum external field reached by this experiment is in order 106 V/m. The change of refractive index as function of E is measured by Michelson interferometer equipment. First, our results show that the refractive index decreases as E increases for all samples. Second, Dn varies slightly square to E, which is still the dominant of linear electrooptic coefficient. The graphs both of acrylic and slides are rather smooth, which indicates that the crystal structures are more regular than aquarium glass. Key Words: electrooptics, refractive index, static electric field
ANALISIS GUGUS FUNGSI PADA SAMPEL UJI, BENSIN DAN SPIRITUS MENGGUNAKAN METODE SPEKTROSKOPI FTIR Anam, Choirul; Sirojudin, Sirojudin; Firdausi, K. Sofjan
BERKALA FISIKA Vol 10, No 2 (2007): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

An analysis of functional groups using FTIR (Fourier Transform Infra Red) spectroscopy in test samples, such as petroleum and spiritus compound has been done.The spectral of the functional groups is observed by comparing of the absorption band which is formed on infra red spectrum with the infra red lines standard and comparing with other known compound. It is expected that functional group identification can be done effectively.Infra red spectrums of petroleum show the group of methyl (CH3), alkenes and aromatic compound. That results analysis is supported by appearance of bending symmetric vibration of C-H and the presence of stretching vibration of C=C from aromatic ring. The spiritus spectrums show the group of hydroxyl from alcohol compound. That analysis is supported by appearance of wide band on 3500–3000 cm-1 and appearance of band on 1000–1100 cm-1.  While test sample spectrum show the group of hidroksil (O-H) from primary alcohol, group of metil (CH3), triple bond (C≡C–H), group of nitril (R–C≡N), double bond (C=C) and C-N.   Keyword: FTIR spectroscopy, vibration, infra red spectrum, absorption, functional group
Sifat Optis Aktif Air dalam Medan Magnet pada Frekuensi Resonansi 50Hz-60Hz Firdausi, K. Sofjan; Lego, Dro Dwi; Sugito, Heri
BERKALA FISIKA Vol 10, No 3 (2007): Berkala Fisika
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Abstract

The interaction between external magnetic field modulated at 50-60 Hz and the dipoles of the sample induced by laser light modulated at 50-100 Hz has been studied. The magnetic field has the maximum value of 170 mT produced by a coil of 810 in turns. The source of light of 632,8 nm and 532 nm is modulated at the resonance value between 30 Hz and 100 Hz. The optical characteristic behavior studied in this research is the change of polarization E-direction of laser light in the aquades samples against the influence of external magnetic field. The result of experiment indicates that the change of laser polarization angle is linearly proportional with the increaseasing of modulated frequency and external magnetic field in sample materials. It is shown that the change of glycerine concentration changes also linearly direction of polarization. The verdet constants measured in the experiment for 632 nm and for 532 nm equal to (0,026 ± 0,005) V (min/g-cm) and (0,025 ± 0,003) V (min/g-cm), respectively. Key words: change of polarization, external magnetic fields, resonance frequency
Studi Pengaruh Medan Radio Frekuensi (RF) pada Minyak Goreng Firdausi, K. Sofjan; Istianah, Istianah; Marhaendrajaya, Indras
BERKALA FISIKA Vol 11, No 1 (2008): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

A study of non linier optic has been carried out for palm oil induced by RF frequency field,e using white light and laser light. The e’s value is produced by RF generator with 2kV of voltage and in the range of frequency between 6.04 MHz and 11 MHz. In this research, he-ne laser with 632.8 nm of wavelength, green pointer laser with 532 nm of wavelength and white light of halogen with maximum power 130, are used as source of light. The physical characteristics observed in the experiment are change of light polarization that is transmitted through palm oil. From experiment result indicates that the change of polarization angle is not linearly dependent on e, At the same condition, the highest changes of polarization angle takes place when providing green laser, upright position of RF frequency field on polarization angle direction  900 for the twice used-palm oil. Keywords: non – linier optics, polarization angle, RF frequency field
Penentuan Dosis Gamma Pada Fasilitas Iradiasi Reaktor Kartini Setelah Shut Down Prasetyowati, Risprapti; Azam, Much.; Firdausi, K. Sofjan; B. S., Edi Trijono
BERKALA FISIKA Vol 9, No 1 (2006): Berkala Fisika
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Abstract

Determination of gamma dose after reactor shut-down around the kartini reactor core have beeb done. The measurement was done at the Lazy Susan (Rotary Rack) and outside the reflector wall which could be used as irradiation facility. Determination of gamma dose was carried out using wide range dosimeter consisting of a Geiger muller detector end a surveymeter. Detector was directed to outside wall reflector and lazy susan through the dry irradiation facility. Measurement was done after shut down for 3 hours with power of 100 kW and interval of ± 5 minutes. The resulting dose rate in reflector wall without neutron source was 1,2 to 0,2 kR/hour and cumulative dose in a 205  minute period was 2,21 kRad. In reflector wall with neutron source was 6  to 0,2 kR/hour and cumulative dose in a 202  minute period was 2,25 kRad.  While in lazy Susan dose rate of 60 to 2 kR/hour and cumulative dose was 42,70 kRad in 203 minutes decay. Gamma decay constant in reflector wall without  neutron source was 0,008 per minute, with neutron source 0,013 per minute. While in lazy Susan gamma decay constant was 0,014 per minute. Keywords : dose, gamm, core and  reflector, reactor
Review Probabilitas Menemukan Elektron dengan Fungsi Gelombang Simetri dan Antisimetri pada Molekul Yusron, Moh.; Firdausi, K. Sofjan; Sumariyah, Sumariyah
BERKALA FISIKA Vol 10, No 1 (2007): Berkala Fisika
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Abstract

The probability density of  and  for the symmetry and asymmetry wave function respectively, for  ion has been simulated. The  and  wave function have been obtained through the solutions of one dimensional time-independent Schrödinger equation.  The  and  are formed then by linear combination of individual solution of wave function of hydrogen atom. The probability density is calculated and simulated for several values of inter nuclear distance in Bohr radius, using Matlab 6.5. The interpretation of  shows that the probability in finding the electron in the space between inter nuclear distance of 0,2 is very small for asymmetry and very large for symmetry wave function. If the inter nuclear distance is made larger in several , the probability becomes smaller. The probability density is just equal to individual in finding electron in a hydrogen atom. Key words: The probability density, symmetry and asymmetry wave function, the  ion.
PENGARUH PENAMBAHAN MINYAK GORENG HEWANI PADA MINYAK SAWIT TERHADAP PERUBAHAN SUDUT POLARISASI Kaltsum, Ummi; Idrus, Hadiyati; Firdausi, K. Sofjan
BERKALA FISIKA 2014: Berkala Fisika Vol. 17 No. 3 Tahun 2014
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Abstract

The use of animal oil for various purposes by the people has inspired this study. The purpose of the study was to distinguish the mixture of cooking oil palm and variety of animal oil (chicken oil, beef oil, and pork oil). The composition of the mixture of palm oil and animal oil is 3:1 mL, respectively. The light source used were He-Ne laser of 1 mW (λ = 633 nm) and IR lamp of 250 watt (λ = 750-800 nm). Measurements were made based on changes in the natural polarization angle (0 kV) and electrooptics (6 kV). The result showed that the natural polarization angle changes and electrooptics of  mixture of palm oil and animal oil greater than pure palm oil, both at He-Ne laser and IR light. This is consistent with the results of the titration test, peroxide value and free fatty acids (FFA) oil mixture was greater than pure palm oil. Change in the polarization angle represents the presence of saturated fatty acids. Animal oils have saturated fatty acid content greater than palm oil, so the polarization angle changes of oil mixture is greater than polarization angle changes of pure palm oil. Keywords: animal frying oil, palm oil, polarization angle
Co-Authors Agustina Setyaningsih Ahmad Kamil Ali Khumaeni Anis Nila Kusuma Arif Fahmi ARIFAH ARIFAH Bunawas Bunawas Catur Edi Widodo Choirul Anam AM Diponegoro Dro Dwi Lego Dwi Satoto Edi Trijono B. S. Eko Sugiyanto Evi Setiawati Hadiyati Idrus Hapsari, Berliana Y. Hari Wibowo Heri Sugito Indras Marhaendrajaya Indri Setiani Istianah Istianah Jatmiko Endro Suseno Krisno Prabowo Lilik Eko Jatwiyono Moh. Yusron Mohammad Munir Much Azam Much. Azam Muchammad Azam, Muchammad Muhamad Adi Nanang Suriansyah Nina Khaerani Nina Widyastuti Prayitno Abadi Rahmadi Setyawan Rahmawati, Aidah Respita Sulistyo Risprapti Prasetyowati Setyoningrum, Aqilatul F.D. Sirojudin Sirojudin Sisca Silvani Soeleman Soeleman Soesanto, Qidir M.B Sulung Edy Nugroho Sumariyah Sumariyah Sutiah Sutiah Thithit Romadhona Tiwiyaningsih, Tiwiyaningsih Ummi Kaltsum Very Richardina Wahyu Adi Wibowo Wahyu Setia Budi Winarno Winarno