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All Journal International Journal of Electrical and Computer Engineering Transmisi: Jurnal Ilmiah Teknik Elektro BERKALA FISIKA Perfecting a Video Game with Game Metrics Proceeding of the Electrical Engineering Computer Science and Informatics Journal of Physics and Its Applications Indonesian Journal of Electrical Engineering and Computer Science
Ngurah Ayu Ketut Umiati
Department Of Physics, Universitas Diponegoro
Astronomy Computer Science & IT Earth & Planetary Sciences Education Electrical & Electronics Engineering Materials Science & Nanotechnology Physics

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PENGUJIAN KEKUATAN DIELEKTRIK MINYAK SAWIT DAN MINYAK CASTROL MENGGUNAKAN ELEKTRODE BOLA-BOLA DENGAN VARIASI JARAK ANTAR ELEKTRODE DAN TEMPERATUR Umiati, Ngurah Ayu Ketut
Transmisi Vol 11, No 1 (2009): TRANSMISI
Publisher : Departemen Teknik Elektro, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (188.095 KB) | DOI: 10.12777/transmisi.11.1.23-36

Abstract

In this paper we explained the breakdown voltage testing that has been done on two dielectric liquid, castrol oil and palm oil using ball to ball electrode. This research observed the effect analysis of electrode gap distance to breakdown voltage, relation between temperature and breakdown voltage, liquid viscocity and breakdown voltage, and increasing temperature to the liquid viscocity. As the laboratory testing result, the breakdown voltage had proportional relation with the electrode gap distance. Viscocity of the liquid influence with its molecular structure and temperature. The liquid dieletricity depend on the electric field exposed and its viscocity. Palm oil has better dielectricity than castor oil in all distance variation and temperature. As the dielectric material must have big breakdown voltage value, the palm oil seen to have this feasibility according to its breakdown voltage 33,060 kV at gap distance 3 mm. Keywords: breakdown voltage, temperature, viscocity, electrode gap distance, dielectric, castor oil, palm oil.
ELECTRIC FIELD CONTOURS IN NON-UNIFORM ELECTRODE SHAPE Umiati, Ngurah Ayu Ketut; Facta, Mochammad
BERKALA FISIKA Vol 23, No 4 (2020): Berkala Fisika
Publisher : BERKALA FISIKA

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Silent discharge is well known method to initiate plasma reaction because initial  discharge is easily triggered by implementing high voltage to the pair of coupled electrodes with a distance. However,  it  is  very  difficult  to  determine  the  exact  amount  of  the  voltage  that  initiates  the discharge.  There  are  many  factors  influence  the  condition  of  initial  discharge  such  as dimensions,  type  and  geometrical  shapes  of  electrode,  thickness  of  insulation,  and  type  of electric field inside the gap between the electrodes. To obtain lower initial discharge voltage, it is urgent to find the best electrode shape producing electric field contours in line with electron emission triggering. This work examines the behavior of electric field and the applied voltage surrounding  electrodes  by  investigating  the  mathematical  expression  for  given  voltage  and generated  electric  field.  The  mathematical  relationship  then  gives  a  basis  of  theoretical background for electric field contours of two shape electrodes. It is also well known that among many electrodes, the non-uniform geometrical shape is preferred to initiate electric field easily. In this study, a hole shape and a bulge type electrode are investigated.Keywords: silent discharge, electric field, differential equation, electrode shape 
Hysteresis Loops for Magnetoelectric Multiferroics Using Landau-Khalatnikov Theory Vincensius Gunawan; Ngurah Ayu Ketut Umiati
International Journal of Electrical and Computer Engineering (IJECE) Vol 8, No 6: December 2018
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (479.771 KB) | DOI: 10.11591/ijece.v8i6.pp4823-4828

Abstract

We present a theoretical discussion of the hysteresis in magnetoelectric multiferroics with bi-quadratic magnetoelectric coupling. The calculations were performed by employing Landau-Khalatnikov equation of motion for both the ferroelectric and ferromagnetic phase, then solve it simultaneously. In magnetoelectric, we obtain four types of hysteresis: ferroelectric hysteresis, ferromagnetic hysteresis and two types of cross hysteresis (electric field versus magnetization and magnetic field versus electric polarization). The cross hysteresis has butterfly shape which agree with the result from the previous research. It can also be seen from that hysteresis, that magnetization / electric polarization can not be flipped into the opposite direction using external electric / magnetic field when the magnetoelectric coupling is bi-quadratic type. Overall, the result shows that Landau-Khalatnikov equation is able to approximate hysteresis loops in multiferroics system.
KERAMIK PORSELEN BERBASIS FELDSPAR SEBAGAI BAHAN ISOLATOR LISTRIK Eva Indiani; Ngurah Ayu Ketut Umiati
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 7, No 2: August 2009
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v7i2.580

Abstract

Electric solid insulator based on ceramics porcelain had been made by using local raw materials: 68% feldspar, 10% kaolinite and 22% quartz, and also added 0%, 5%, 10%, 15%, 20%, 25% cullet (From total mass). The forming process of the porcelain was conducted by milling the raw materials using ball mill and screened using 200 mesh screening. The samples were formed by using the dry-press method with the pressure of 50MPa, then the samples is sintered at temperature of 1000oC, 1050oC, 1100oC, 1150oC for 2 hours. The properties of the samples had been analyzed for their  shrinkage, density, bending strength and resistivity. The result of the experiment showed that the optimum value was reached by ceramic which was added by 15% cullet and sintered at temperature of 1100oC. This ceramic had shrinkage of 9,70%, density of 2,44 g/cm3, bending strength of 86,73 MPa and the resistivity at 25oC is 2,32x108 Ωcm
Geometrical Shape Investigation for Electrodes in Silent Discharge Chamber Mochammad Facta; Ngurah Ayu Ketut Umiati; Agung Warsito
Proceeding of the Electrical Engineering Computer Science and Informatics Vol 3: EECSI 2016
Publisher : IAES Indonesia Section

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (634.287 KB) | DOI: 10.11591/eecsi.v3.1153

Abstract

Silent discharge is the most prominent method to carry out plasma reaction because. discharge is easily initiated by injecting alternating current in high voltage to the pair of separated electrodes. The electron emission from surface of dielectric placed on instantaneous cathode is stimulated by ion induced electron emission. In this method, spark is avoided by placing insulation material to either one or both of the electrodes. In practical, it is very difficult to determine the exact limit of the voltage that initiate the discharge by mathematical analysis because it depends on many factors, namely dimensions, type and geometrical shapes of electrode, thickness of insulation, and type of electric field inside the discharge gap. To get lower initial voltage for discharge, it is important to find the best geometrical shape of electrode in relation to skin effect that trigger electron emission. This work investigates the behaviour of charges, current, electric field and voltage surrounding electrodes with various geometrical shape.Silent discharge is the most prominent method to carry out plasma reaction because. discharge is easily initiated by injecting alternating current in high voltage to the pair of separated electrodes. The electron emission from surface of dielectric placed on instantaneous cathode is stimulated by ion induced electron emission. In this method, spark is avoided by placing insulation material to either one or both of the electrodes. In practical, it is very difficult to determine the exact limit of the voltage that initiate the discharge by mathematical analysis because it depends on many factors, namely dimensions, type and geometrical shapes of electrode, thickness of insulation, and type of electric field inside the discharge gap. To get lower initial voltage for discharge, it is important to find the best geometrical shape of electrode in relation to skin effect that trigger electron emission. This work investigates the behaviour of charges, current, electric field and voltage surrounding electrodes with various geometrical shape.
The Electric Susceptibility of Bi-Layers Ferroelectrics Vincensius Gunawan; Ngurah Ayu Ketut Umiati; Agus Subagio
Journal of Physics and Its Applications Vol 1, No 2 (2019): May 2019
Publisher : Diponegoro University Semarang Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jpa.v1i2.4860

Abstract

In order to enhance insight of layered structure, we perform numerical calculation to obtain the dynamic electric susceptibility in bi-layers ferroelectrics. Since susceptibility is a parameter which gives response to the external field, then determination of this parameter is important. A lattice model is employed to slice bilayer structure into several lattices.  Then, Landau-Khalatnikov equation of motion is used in each lattice to construct a matrix equation of equation of motion.  The solution is obtained by applying entire-cell effective medium.  We find that the homogeneity of dynamic polarization is different from homogeneity of the single individual layer due to the existence of interlayer interaction.  As a result, the electric susceptibility is also altered.  It is also noticed that there is a relation between the homogeneity of dynamic polarization and the value of electric susceptibility near resonant frequency.  The higher the homogeneity, the bigger the values of susceptibility will be. 
Electrical Conductivity of Polyaniline Fiber Synthesized by Interfacial Polymerization and Electrospinning Ngurah Ayu Ketut Umiati; Kamsul Abraha; Kuwat Triyana
Indonesian Journal of Electrical Engineering and Computer Science Vol 5, No 1: January 2017
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v5.i1.pp85-89

Abstract

Polyaniline fiber is a promising biosensor material due to the capability of this material as an effective mediator for electron transfer. The polyaniline in fibre has wider surface to increase the electron transfer. In this work, polyaniline structure synthesized by interfacial polymerization was compared to polyaniline structure obtained from electrospinning to get a better fibre structure. Interfacial polymerization was carried out to form a polymerization between the water phase and the organic phase. The water phase was prepared from dopants, initiator and aquadestilata and the organic phase was was made from toluene as an organic solvent and aniline monomer. Electrospinning was conducted by using a dc high voltage 15 kV and 0.5 mm syringe needle to produce fibers from a melt polymer solution taken from interfacial polymerization. The scanning electro microscope results confimed the formation of polyaniline in structure of fiber. Resistance measurement by using LCR meter showed that polyaniline fiber resulted from electrospinning is more conductive than polyaniline fiber formed by interfacial polymerization method.  
Co-Authors Agung Warsito Agus Subagio Eva Indiani Kamsul Abraha Kuwat Triyana Mochammad Facta Vincensius Gunawan S.K.