Ria Amitasari
Jurusan Fisika, Universitas Diponegoro, Semarang
Articles
5
Documents
RANCANG BANGUN ALAT UKUR INTENSITAS CAHAYA UNTUK MENENTUKAN SUDUT PUTAR JENIS SUATU BAHAN BERBASIS MIKROKONTROLER AVR ATMEGA8535

YOUNGSTER PHYSICS JOURNAL Vol 1, No 1 (2012): Youngster Physics Journal Oktober 2012
Publisher : YOUNGSTER PHYSICS JOURNAL

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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 (θ) based on the law of Malus. The specific rotation (α) 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

REVIEW PENGUJIAN HUKUM MALUS DAN SIFAT OPTIS AKTIF LARUTAN GULA MENGGUNAKAN SISTEM DETEKSI CAHAYA

BERKALA FISIKA Vol 16, No 1 (2013): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

Abstract In this paper, we review the test results of Malus’ Law and optical activity of sugarsolution using a system light detector. Two polarizers were used in the experiment to serve thechoice of a certain direction of electric field of light and to determine the change of polarizationangle. The change of transmitted intensity were measured using LDR detector which was thenacquisitioned by microcontroller and displayed via LCD and computer using  Microsoft Visual Studio C#. The experiment result is in agreement to the Malus’ Law with correlation coefficient of 0.99, and by using the equipment we obtain linearity between the change of polarization angle andconcentration of sugar solution, which is appropriate to the theory, as well. The specific rotarypower is (54±2) o/dm(g/mL) in the experimental uncertainty.Keywords: Malus law, change of polarization angle, light detector

DETEKSI DINI KUALITAS MINYAK GORENG DAN STUDI AWAL TINGKAT KEHALALANNYA MENGGUNAKAN POLARISASI ALAMI

BERKALA FISIKA 2014: Berkala Fisika Vol. 17 No. 3 Tahun 2014
Publisher : BERKALA FISIKA

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Abstract

In this paper, we investigate natural light polarization for preliminary test of quality and authentication (halal) level of frying oil. Recently standard methods used are usually based on Indonesian National Standard (SNI), however all parameters are very difficult to be determined simultaneously. On the other hands even the test is time consumed, inexpensive, complicated and also preliminary treatments required, which is a major problem in era of rapid information need. One of an alternative solution is to use natural light polarization method. In the experiment, several vegetable frying oils and animal oils are used to be tested. The change of polarization angle is used to indicate the level of oil quality and its authentication. The result shows that higher polarization indicates lower oil quality relative to the others, which is in agreement to the previous study. This method is, not only, able to differentiate various edible vegetable oils, but also to distinguish edible oils and expired oils. More over, it has a prospect to indicate an authentication of oil that is a subject of a halal or not-halal case.This method is relative simply, not time consumed, conducted accurately without any previous treatments, and it provides a good prospect as a preliminary test for oil quality and its authentication. Keywords: Natural polarization, oil quality, halal or authentication level

PENGARUH GAIN TERHADAP FWHM DAN FWTM PADA CITRA B-MODE ULTRASONOGRAM (USG)

BERKALA FISIKA 2015: Berkala Fisika Vol. 18 No. 2 Tahun 2015
Publisher : BERKALA FISIKA

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Abstract

The effect of gain to The Width at Half Maximum (FWHM) and Full Width at Tenth Maximum (FWTM) on B-mode image ultrasonogram (USG) has been investigated. The aim of this research is to determine the effect of gain on the spatial resolution according the measurements of FWHM and FWTM. The evaluated resolution type is axial and lateral. This research used phantom multipurpose multi tissue with gain (30 dB, 35 dB, 40 dB, 45 dB, 50 dB, 55 dB and 60 dB) on frequency variation source 6,2 Mhz, 8 MHz dan 10MHz. The axial and lateral resolution images were obtained by using USG which uses B-Mode imaging. The measurement was made by using digital image and calculated objectively with MATLAB. The measurement of FWHM and FWTM was obtained from IP-PSF analysis (In Plane-Point Spread Function) using approximation for the Gaussian function. The result shows that there is influence from gain on FWHM and FWTM. The decreasing gain resulted in decreasing of FWHM and FWTM. The decreasing of FWHM and FWTM represents better spatial resolution, and vice versa. Keywords: FWHM, Gain, Point Spread Function, Spatial resolution, USG,

Metode Elektrooptis sebagai Pendeteksi Radikal Bebas dan Prospek untuk Evaluasi Total Mutu Minyak Goreng

INDONESIAN JOURNAL OF APPLIED PHYSICS Vol 3, No 01 (2013): IJAP VOLUME 03 ISSUE 01 YEAR 2013
Publisher : Department of Physics, Sebelas Maret University

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Abstract

One main problem of standard methods for determination of frying oil quality is various parameter of indicators with their various wide of methods or equipments. In this research we proposed a new method for determination of oil quality using single electrooptics parameter to replace previous indicators. The samples used in the experiment were various conditions of palm oils from the same brand. The level of oil quality was proposed by the value of 2, which represents as the relative number of free radicals produced in the sample. The change of polarization was measured by the value of as the samples were induced by an external electric field using high voltage dc power supply. At room temperature of 28 C electrooptics method seems capable to detect free radicals and to distinguish all kinds of palm oils. This method has an opportunity to provide a single parameter of oil quality and an evaluator of halal or authentic food from fats.