Browsing by Author "U., Lazuardi"
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Item PEMBUATAN ALAT UKUR KUAT MEDAN MAGNET INDUKSI BERBASIS KOMPUTER(2013-03-05) Gusrini, Elni; U., Lazuardi; Setiadi, Rahmondia N.Magnetic field is an important physical quantity in many research fields such as research in geology, geophysics, and research in the field of magnetism. In this paper, a computer-based instrument for measuring induced magnetic field strength is decribed. The instrument system for measuring magnetic field strength is an instrument with an external measuring unit using KMZ10B magnetoresistive sensor with analog amplifiers controlled by an ADC 7822 microprocessor, and connected to host personal computer with running application software based Visual C++ for data acquisition. Based on various coil dimension and excitation currents, the system can be configured during the measurement. Induced magnetic field strength can be detected by measuring the inductance of the inductive coil in the vicinity of the position sensor. The instrument has been tested and calibrated using a standard calibrator of magnetic field instrument Teslamater FH51. A linier model based on the transfer function is used to convert and to evaluate the sensor output. Measurements with constant and variable current have been made at the center of solenoid as well as on the end of the solenoid resulting maximum field strength of BC = 1,51mT and BE = 1,23mT at the center and on the end of solenoids core respectively. The experiments show that magnetic field strength will increase with the number of coil winding and excitation currentItem Pembuatan Ec-Probe Untuk Mengukur Kelembaban Tanah Pertanian Mempergunakan Modifikasi Konfigurasi Wenner-Array(2013-03-05) Sinaga, Santon; U., Lazuardi; Setiadi, Rahmondia N.This study aims to create a soil moisture measuring device based on the Wenner method. The main circuit of the tool uses an IC a type LM 317A with output voltage 1.2 Volts to 37 Volts and can pass current of 1.5 A. The sensor used is a type of cylindrical electrodes with length of 705 mm and the detection electrode consists of a ring electrode with radius equal to 15 mm in diameter and 4 mm thick, spacerring and cone part can be opened. Testing soil moisture measuremen of Inseptisol that taken from UPT Faperta UR, Andisol from Bukittinggi and Entisol from area of watershed Kampar and measured using the calibrator Soil Tester Lutron produce five levels of soil moisture for each sample. Soil samples with moisture is tested and characterized with a modified 4- point Wenner by injecting a current of 1 mA. these modeling obtained a general mathematical equation model that describes the relationship between the electrodes voltage (UO) and soil moisture (θw) on the soil types Uo yo A Tw BTw2 CTw3 the equation is empirical and has different values for those three soil samplesItem Study Laju Perpindahan Panas Konveksi-Bebas Dari Berbagai Fluida Pada Silinder Berongga Berdasarkan Fungsi Jarak dan Waktu(2013-03-05) Ningsih, Kurnia Gusti; Salomo; U., LazuardiHeat transfer is commonly found in industry such as the heat transfer between pipe and air in steam pipe and boilers. Heat transfer can be divided into three types that are conduction, convection, and radiation. In this paper, a measurement of heat transfer rate that occurs in water and oil in a pipe based on free convection method is described. Temperature measurement system on the fluid using a k-type thermocouple sensor as inputs is connected to an amplifier was while the output of the circuit is connected to an ADC Card Velleman for data acquisition and read by a personal computer. Thermocouple sensors have been tested and calibrated using an oven, then a linear equation was obtanied based on a function of voltage and temperature to convert the sensor output. Based on four point intervals, sensor temperature changed suit with power various. At the minimum and maximum power variation of each sensor value, the specific heat and the coefficient of thermal heat of the fluid. Were obtained with minimum power 216 watt and maximum power 322.7 watt in fluid water, specific heat value obtained are 4026.11 J/KgoC and 4398.8 J/KgoC. Then thermal coefficient are 1.67 W/m2oC and 1.21 W/m2oC. In the petroleum fluid with the minimum 216 watt and maximum 322.7 watt power, specific heat value obtained are 3230.3 J/KgoC and 3891.9 J/KgoC. Then thermal coefficient are 1.22 W/m2oC and 1.48 W/m2oC. The research shows that the longer time is required for the temperature to reach the steady state with the greater power used on it