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Walfred Tambunan
Department Physics: FMIPA - Universitas of Riau
Earth & Planetary Sciences Education Electrical & Electronics Engineering Energy Materials Science & Nanotechnology Physics

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EFEK ADITIF Bi2O3 TERHADAP MIKROSTRUKTUR DAN KOEFISIEN NON LINEAR VARISTOR ZnO. Tambunan, Walfred; Malik, Usman
2302-0792
Publisher : Edu Research

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Abstract

The varistor ZnO has been made by using raw materials: ZnO(E-Merck) and additive 0 %, 2.5 %, 5%, 7.5%, and 10% wt.Bi2O3. The important property of varistor ZnO is coefficient ofnon linier () and it can give influence correlation betweencurrent I and voltage V. The mixing process of raw materialswas done by using magnetic stirrer and liquid acetone asmedia, and then was dried at 60oC, and also grinded untilpassing 400 meshes. Pellet was made by using pressing 50MPa, and fired at 1050oC with holding time 2 hours. Afterfiring, all samples are characterized, such as: measurement ofcoefficient of non linier (), and observation of microstructureby using Scanning Electron Microscope (SEM). The resultsshow that sample without additive has  less than 5 and thissample has not properties as varistor, but the highest value of is 64 for sample with additive 7.5% Bi2O3. The result ofphotos SEM shows that the increase of percentage of additiveBi2O3 can influence of formation grain boundary and grainsize. Where, value of coefficient of non linier () is depend onexisting of grain boundary and thickness of grain boundary.
SIMULASI 3 DIMENSI DISTRIBUSI PANAS PLAT KNALPOT MOBIL UNTUK ELEMEN TERMOELEKTRIK Adli, Wildan; Tambunan, Walfred; Umar, Lazuardi
Komunikasi Fisika Indonesia Vol 13, No 12 (2016)
Publisher : Komunikasi Fisika Indonesia

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This study simulates the distribution of heat in the conductor plate micro energy generation based module Thermoelectric Generator (TEG) type 40-40-10 / 100 to optimize the absorption of heat from the vehicle exhaust waste heat. The module has a maximum operating temperature of 423K. The modeling is done using MATLAB with a modified diffusion equation by application of 900K of temperature as boundary condition on the surface of the base plate which is in contact with the heat source. The plate with aluminum material modeled in varies form of solid, hollow, hollow gitter, hollow heatsink, with dimensions of 110mm long, 60mm wide, 30mm thick base and 30mm thick bulge. The best temperature drop obtained for ΔT = 178,67K (19.85%) produced by the shape of a hollow heatsink plate. The resulting temperature of this model is then lowered back with varying types of material such as aluminum, copper, iron, and stainless steel, as well as by varying the number of TEG array that is 1 to 4-arrays, each array consisting of two modules. Drop in temperature that comes closest to the maximum TEG operating temperature is a drop in temperature that generates the final temperature of 402K, which comes from hollow-with-heatsink stainless steel plate with 50mm of thick and 4-arrays formation.
EFEK ADITIF Bi2O3 TERHADAP MIKROSTRUKTUR DAN KOEFISIEN NON LINEAR VARISTOR ZnO. Tambunan, Walfred; Malik, Usman
Edu Research Vol. 1 No. 2 (2012): Jurnal Pendidikan
Publisher : Universitas Pasir Pengaraian

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2067.681 KB)

Abstract

The varistor ZnO has been made by using raw materials: ZnO (E-Merck) and additive 0 %, 2.5 %, 5%, 7.5%, and 10% wt. Bi2O3. The important property of varistor ZnO is coefficient of non linier () and it can give influence correlation between current I and voltage V.
Co-Authors Lazuardi Umar Usman Usman Wildan Adli, Wildan