K. Sofjan Firdausi
Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro Semarang

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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.
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
Publisher : 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
Publisher : BERKALA FISIKA

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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 (? = 633 nm) and IR lamp of 250 watt (? = 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
RANCANG BANGUN ALAT UKUR INTENSITAS CAHAYA UNTUK MENENTUKAN SUDUT PUTAR JENIS SUATU BAHAN BERBASIS MIKROKONTROLER AVR ATMEGA8535 Amitasari, Ria; Firdausi, K. Sofjan
YOUNGSTER PHYSICS JOURNAL Vol 1, No 1 (2012): Youngster Physics Journal Oktober 2012
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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Abstract

ABSTRACT The Research has been conducted to design and realize an instrument for measuring the intensity of light to determine the specific rotation of  material based to microcontroller AVR ATmega8535. The specific rotation to determine the type of optical properties of a material. Measuring instruments using LDR as light sensors acquired using a microcontroller. Light intensity are displayed using LCD. Light intensity was measured to obtain the polarization angle (?) based on the law of Malus. The specific rotation (?) obtained from the change polarization angle due to the material passing through 1 cm at each change of concentration of sugar solutions. The source of light was halogen lamp 50 watt. Materials used for polarization calibration tool are solutions of sugar. The study producing an instrument measuring the intensity of light that can be used to determine the optical properties of materials based on the specific rotation using the law of Malus. Measuring instrument of light has been calibrated with standards Luxmeter Lutron LX 101 and gave linier with a correlation coefficient of 0.99. The instrument produced specific rotation of sugar (54.17 ± 2.16) o/dm(g/mL) and gave linier correlation coefficient of 0.99. Key words: optical properties, specific rotation, the law of Malus, light intensity, LDR,  microcontroller,LCD
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
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
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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
PENGUKURAN PANJANG KOHERENSI MENGGUNAKAN INTERFEROMETER MICHELSON Setyaningsih, Agustina; Marhaendrajaya, Indras; Firdausi, K. Sofjan
BERKALA FISIKA Vol 10, No 4 (2007): Berkala Fisika
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Abstract

A simple measurement of coherence length of He-Ne laser, red diode laser, and green diode laser using Michelson interferometer has been conducted. The steps in this research were setting up the Interferometer by places movable mirror on mirror rail. To determine the coherence length of the laser?s light, movable mirror has been shifted until the interference fringes disappear on the screen. Results of measurement for the coherence length of He-Ne laser I is  cm, He-Ne laser II is  cm, red diode laser I is cm, and green diode laser II is  cm. Keywords: Coherence, coherence length.
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.
RANCANG BANGUN SISTEM PENGUKUR INTENSITAS CAHAYA MENGGUNAKAN MICROSOFT VISUAL STUDIO C# UNTUK MENENTUKAN SUDUT PUTAR JENIS LARUTAN GULA Istiyawan, Wardono; Firdausi, K. Sofjan; Sugito, Heri
YOUNGSTER PHYSICS JOURNAL Vol 1, No 1 (2012): Youngster Physics Journal Oktober 2012
Publisher : Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro

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Abstract

A system of measuring the light intensity to determine the specific rotary angle of  sugar has been carried out. Research is done using a computer with a Microsoft Visual Studio C#. In this research there are some stages as follow light sensors and the system of measuring polarization angle. LDR as light intensity sensor, the result has been processed in a series of conditioning at the output signal. The result of  this series can be input in interface application.  Measurement of polarization angle can be done by counting average value of the intensity before it gets into the materials and thereafter. This system has been realized and can show the results obtained in the form of graphs and can be stored. The value of the angular turn kinds of sugar unmeasured is (51,33±0,42) omL/dm gram. Results of testing equipment and the characteristics of the sensor with a linear regression coefficient R2 = 0,9906 and  SD = 0,82. Keyword : Microsoft Visual Studio C#, Specific rotary angle, Polarization angle,  LDR
STUDI RADIOGRAFI MAKRO DENGAN VARIASI JARAK SUMBER SINAR-BAYANGAN (SID) DAN UKURAN FOKUS TERHADAP PEMBESARAN BAYANGAN Suriansyah, Nanang; Setiawati, Evi; Firdausi, K. Sofjan
BERKALA FISIKA Vol 10, No 4 (2007): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

The dependence of radiograph magnification (M) on the ratio focal spot size to object ( has been studied. The object shape like a coin made from iron which different diameter and variation focal spot size have been used. The experiment condition were set up at the distance of the object to the film of 0 cm (object stick the film) and 45 cm, with the tube voltage of 50 kV, tube?s current of 100 mA, and time of 0.04 s. The results show that the increasing of (leads to the increasing of (M) when the distance of the object to the film is more than 0 (b>0).   Keyword: focal spot, SID, magnification radiograph