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INDONESIA
BERKALA FISIKA
Published by Universitas Diponegoro
ISSN : -     EISSN : -     DOI : -
Core Subject : Science,
Physics
BERKALA FISIKA adalah jurnal saintifik yang diterbitkan secara periodik 3 bulanan. Jurnal ini memuat kajian-kajian Fisika baik kajian teoretik maupun hasil eksperimen. Jurnal ini juga memberi ruang yang luas bagi kajian – kajian aplikasi fisika dalam bidang teknologi, ilmu-ilmu hayati dan kedokteran.
Arjuna Subject : -
Articles 369 Documents
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PENENTUAN CT DOSE INDEX (CTDI) UNTUK VARIASI SLICE THICKNESS DENGAN PROGRAM DOSXYZNRC Andriani, Intan; Anam, Choirul; Setiawati, Evi
BERKALA FISIKA Vol 15, No 3 (2012): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

The calculation of CT dose and CTDI has been done by using DOSXYZnrc software. Two kinds of phantoms have been used, i.e air and PMMA phantoms. The volume of phantoms 16 x 16x 16 cm3. The simulation carried out at 120 kV and the particles source 106. The calculation ofdose at the mid of phantom at the z axis, every voxel 0,2 x 0,2 x 0.2 mm3. The  variation of slicethickness were 5 mm, 10 mm, 15 mm and 20 mm. The dosages at every point then were plotted tofind out dose profile, and then were integrated to find out the CTDI. It was obtained that the peakvalue  on the air phantom has a higher value than the PMMA phantom. In the air phantom at theslice thickness of 5 mm, 10 mm, 15 mm and 20 mm were 68.28%, 80.49%, 90.91%, 99.86%. Whilein PMMA were 63.68%, 77.42%, 89.32%, 100%. At the penumbral region, it was obtained thatdosage at the PMAA phantom has a higher than the air phantom. CTDI from the PMAA phantomwas 212.50% and the air phantom was 184%. It was obtained that CTDI independent of slicethickness at the range 5-20 cm.Keywords: DOSXYZnrc, Slice thickness, CTDI
Arus Terobosan Pada Transistor Dwikutub Struktur Hetero Si/Si1-xGex/Si Anisotropik Melewati Basis Tergradasi (Graded Base) Hasanah, Lilik; Khairurrijal, Khairurrijal
BERKALA FISIKA Vol 13, No 2 (2010): Berkala Fisika, Edisi Khusus
Publisher : BERKALA FISIKA

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Abstract

Tunneling current in bipolar transistors Si/Si1-xGex/Si anisotropic hetero structure for germanium conditions on a constant basis is not analyzed here. The concentration of germanium in the base which is not constant will result in the potential profile at the base is not flat, but will be graded according to the germanium concentration. Tunneling current calculation is performed semi-analytically and numerically. The calculation result obtained then matched with experimental data. The results show that the results of analytical calculations with results of semi-numerical calculations. While analytical calculations with experimental data only flows from the VBE 0.3 to 0.6 V.   Keywords: Tunneling current, germanium concentration, anisotropic material, transfer matrix method, hetero structure bipolar transistor
EVALUASI KUALITAS BEBERAPA JENIS MINYAK GORENG KEMASAN SETELAH DIPANASKAN MENGGUNAKAN SIFAT ELEKTROOPTIS Murni, Sri; Bawono Putranto, Ari; Hidayanto, Eko; Firdausi, K Sofjan
BERKALA FISIKA Vol 16, No 3 (2013): Berkala Fisika
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Abstract

In this report, we have determined the average value of polarization angle for various edible oils, before and after heating. The change of polarization angle was measured averagebetween potential differences 0-9 kV. The heating time for the samples was conducted up to 10 hours at average temperature by 180°C. The source of light was He-Ne Laser 1 mW (633 nm) with optical length of samples of 1 cm. In agreement to the previous experiment, our result shows that all vegetable oils provide increasing of free radicals indicated by increasing polarizationangle for longer heating time. For the heating time interval 0-10 hours, the level degradation ofoil rises quadratically. From various edible oils, olive oil is still the relative best quality from allsamples in this experiment. This method, once again, shows more powerful relative to otherstandard methods.Keywords: frying oil, electrooptics, polarization angle
Rancang Bangun Sistem Pengukur Konsentrasi Larutan Tembaga Sulfat (CuSO4) Menggunakan Komputer Sumariyah, Sumariyah; Endro Suseno, Jatmiko; L, Fitria
BERKALA FISIKA Vol 10, No 3 (2007): Berkala Fisika
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Abstract

A system  of    Sulphate Copper (CuSO4) liquid consentration measurement by using compute has been made. The display of it through monitor in the computer with the limitation of measurement  0.1 M to 1M. The main components of the measure system of   Sulphate Copper (CuSO4) liquid consentration are : tungsten filamen light which include in the sample and photodioda light sensor also IC 741 as a Operational Amplyfier to strengthen the tension of sensor output. As the chage of the output analog signal power tobe digital signal ADC 0809 is used. And also as an interfce which is the pheripheral instrument of communication equipment with computer is used PPI 8255. The software on  this measure system uses Turbo Pascal version 7.0. This system had been realized and can measure the Sulphate Copper (CuSO4) liquid consentration wich the linier regresion equal is , with X hole is the sample consentration (M) and Y hole is the measure result of the concentration (M) and the deviation is 0.0326.
PERANCANGAN DAN PEMBUATAN SENSOR TDS PADA PROSES PENGENDAPAN CaCO3 DALAM AIR DENGAN METODE PELUCUTAN ELEKTRON DAN MEDAN MAGNET Martani, Maylita; Endarko, Endarko
BERKALA FISIKA 2014: Berkala Fisika Vol. 17 No. 3 Tahun 2014
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Abstract

Total Dissolved Solids (TDS) meter has successfully been fabricated based on the principle of conductivity. Control system for monitoring the TDS level in the mini plant have been performed by microcontroller ATMega16 and Personal Computer. The study was to control a precipitation process of CaC03 in the water. Values of TDS from water sample in the mini plant have been monitored and controlled in real-time. All data have been recorded by microcontroller and then, the data will be sent to personal computer via USB interface. Monitoring data will be displayed in a computer screen. The result showed that the system could be used to control level of TDS at 356 - 300 ppm. Keywords : gravity of CaC03, Conduktivity, Control
Solusi Numerik Model Dinamik Perlakuan Immunotherapy pada Infeksi HIV-1 Kartono, Agus; Rosidah, Rosidah; Arif, Ardian
BERKALA FISIKA Vol 13, No 1 (2010): Berkala Fisika
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Abstract

There are several types of treatment options that can slow the progression of HIV that can be offered if the number of CD4 + cells has been known for certain, one treatment is by immunotherapy with interleukin-2 (IL-2). This type of treatment is to increase the immune system that can help the body fight against the infection itself. Efforts to raise an immune response would be appropriate to reduce the amount of virus. This brings new hope for treatment of HIV infection and the type of treatment is being researched. Interleukin-2 (IL-2) is most of the cytokines which are proteins made by the body. T-helper cells, a type of white blood cells, produce IL-2 when they were stimulated by infection. In this study, a model of HIV disease progression than individuals not treated can be expressed in a mathematical model, and also expressed immunotherapy model to see the dynamics of viral populations and the population of CD4 + T cells from HIV disease based on ordinary differential equation (ODE). This study aims to calculate the numerical solution immunotherapy mathematical model in HIV infection and a mathematical model to predict the outcome of immunotherapy treatment strategies in HIV infection. Keywords: HIV, CD4 + T cells, immunotherapy, mathematical modeling
STUDY OF ELECTROOPTICS BEHAVIOUR OF NAPHTHALENE AND ANTHRACENE Firdausi, K Sofjan; Khumaeni, Ali; Richardina, Very; Arianto, Fajar; Budi, Wahyu Setia
BERKALA FISIKA 2015: Berkala Fisika Vol. 18 No. 3 Tahun 2015
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Abstract

In this paper, we demonstrate electro-optics behaviour of naphthalene and anthracene using change of polarization of sample induced by external electric field. The source of light for polarization was 1 mW-he-ne Laser 633 nm. The induced external Electric field was produced by high DC voltage 0 – 7 kV. The samples were diluted in solutions-form using wash-benzene. The result shows that anthracene has higher polarizability than naphthalene, which is indicated by higher change of polarization in anthracene than naphthalene. The Assumption that potential difference is proportional to the distance between molecules is shown qualitatively by graphs of Van der Waals potential energy or force between molecules. In this case, anthracene has higher level Energy than naphthalene so that it can be used in visible excitation for environmental spectroscopy. Keywords: electro-optics, polarization, naphthalene, anthracene, Van der Waals potential energy 
Aplikasi Transduser Ultrasonik Jenis Immersion Transducer Untuk Karakteristik Media Cair Dan Pengukuran Tingkat Kekasaran Permukaan Beton Sugito, Heri; Suryono, Suryono; Layla, Diana
BERKALA FISIKA Vol 12, No 4 (2009): Berkala Fisika
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Abstract

Research of the application of ultrasonics for liquid medium characteristic and measurement of level of surface roughness of concrete have been done using immersion transducer. This purpose of research is to know characteristic some dilutions based on the atanuasi coefficients and measure surface roughness of concretes based on time of flight. In this research applied by ultrasonic transducer with frequency of 1 MHz.  At attenuation method, awakened ultrasonic signal through pulse generator and connected at transmitter transducer. Ultrasonic wave which transmitted through liquid medium will experience received finite attenuation of receiver. Media liquid which applied is oil and cooking oil. At method time-of-flight, measurement done with object scan which turned around counted 200 rotation apply motor stepper. Object which applied as component of test that is concrete. Reason of selec,choose it this specimen is to minimize attenuation so that will enlarge the bound. Transducer will transmit modulation to object through modulation transmiter and receiver. Result from scanner is presented at CRO ( Cathode Ray Oscilosco). Research result to liquid medium sample showing existence of tendency of increase of attenuation value for ex-oil- and ex-cooking oil if each compared with oil was new and new cooking oil. From measurement of level of surface roughness, obtained by is surface roughness average yield of  concrete A ( Radium of a minimum of 10%, and Ra maximum 16%), and concrete B ( Radium of a minimum of 8%, and Ra maximum 17%). This research result give hope that this method can be developed for inspection innoxious at solid and liquid medium.   keyword : Ultrasonic, attenuation coefficient, level of crudity, Time of Flight
SISTEM PENGENALAN WAJAH DENGAN METODE EIGENFACE DAN JARINGAN SYARAF TIRUAN (JST) Mulyono, Tri; Adi, Kusworo; Gernowo, Rahmat
BERKALA FISIKA Vol 15, No 1 (2012): Berkala Fisika
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Abstract

The development of security systems led to the development of face recognition system using image processing techniques.Research was conducted to identify a face image automatically with theeigenface method. The method used is a normalization, eigenface, neural network training and testing.Eigenface is used to reduce the dimension vector face becomes much simpler (eigen vector). Eigen vectorsobtained are used by back propagation neural network training process and recognition. Then do thetesting process using the image of a face that has not been used in the training process.The results showed the use of neural networks and eigenface to face recognition can give a goodaccuracy. The system is able to produce an acuracy of 84.6% with a FAR (False Acceptance Rate) =16.2%, FRR (False Rejection Rate) = 20% and EER (Equal Error Rate) = 0.3.Keywords : face recognition, eigenface, eigen vector, neural network
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
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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

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