Pontianak, Indonesia

University of Tanjungpura

www.untan.ac.id
Pontianak, Indonesia

Tanjungpura University or UNTAN is a public university located in the city of Pontianak in West Kalimantan, Indonesia.Hamzah Haz, former Indonesian Vice President once taught at the University. Wikipedia.

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Gianto R.,University of Tanjungpura
International Journal on Electrical Engineering and Informatics | Year: 2016

TCSCs (Thyristor Controlled Series Capacitors) have been used by many modern electric power system utilities for regulating power flow and increasing power transfer capability. The ability in regulating the transmittable power flow also implies the potential application of the device for the improvement of system stability and dynamic performance. The research reported in this paper investigates the application of TCSC in improving dynamic performance of large interconnected electric power system. Simulation results show that the TCSC provides better system stability and dynamic performance. The results have also been verified through eigenvalues analysis and confirmed by time-domain simulations. © 2016, School of Electrical Engineering and Informatics. All rights reserved.


Desnita R.,University of Tanjungpura | Wahdaningsih S.,University of Tanjungpura | Hervianti S.,University of Tanjungpura
International Journal of PharmTech Research | Year: 2016

Objective: To determine the antioxidant activity of microemulsion of purple sweet potato ethanol extract that is formulated using a various concentration of Span 60. Methods: The purple sweet potato was extracted with ethanol using maceration method. Then IC50 value of ethanol extract of purple sweet potato was determined, and formulated in microemulsion with various concentration of Span 60. Each formula has a concentration ratio of Span 60 as follows, Formula A (FA) 0.75%, Formula B (FB) 1%, and Formula C (FC) 1.25%, and use cosurfactant PEG 400 in the ratio of surfactant: cosurfactant 1: 1 for each formula. Measurement of antioxidant activity was conducted using DPPH method. The physicochemical properties and stability of microemulsion is tested for 28 days, covering organoleptic, pH, specific gravity and centrifugation tests. The most stable microemulsion was tested for its antioxidant activity by the value of percent inhibition, then the size of microemulsion globules was observed using PSA (Particle Size Analysis). Results: IC50 of ethanol extract of purple sweet potato obtained at 38.246 ppm. Organoleptic and centrifugation test showed the occurrence of creaming at FC. pH was in the range of pH that is safe for the skin (5.8 to 5.9) with the density of microemulsion that’s relative stable. FA is the most stable formula. FA showed antioxidant activity with percent inhibition of 81.37254% with globule size from 111.1 to 152.4 nm. Conclusion: Based on research that has been done, it can be concluded that microemulsion formula A with a concentration of 0.75% Span 60 generates the most stable microemulsion and has antioxidant activity with percent inhibition of 81.37254%. © 2016, Sphinx Knowledge House. All rights reserved.


Hardiansyah,University of Tanjungpura
International Journal of Electrical and Computer Engineering | Year: 2016

In this paper, a modified artificial bee colony (MABC) algorithm is presented to solve non-convex dynamic economic dispatch (DED) problems considering valve-point effects, the ramp rate limits and transmission losses. Artificial bee colony algorithm is a recent population-based optimization method which has been successfully used in many complex problems. A new mutation strategy inspired from the differential evolution (DE) is introduced in order to improve the exploitation process. The feasibility of the proposed method is validated on 5 and 10 units test system for a 24 h time interval. The results are compared with the results reported in the literature. It is shown that the optimum results can be obtained more economically and quickly using the proposed method in comparison with the earlier methods. Copyright © 2016 Institute of Advanced Engineering and Science. All rights reserved.


Ramli M.A.M.,King Abdulaziz University | Hiendro A.,University of Tanjungpura | Twaha S.,Skyline Technical Services Ltd.
Renewable Energy | Year: 2015

This paper analyzes a hybrid energy system performance with photovoltaic (PV) and diesel systems as the energy sources. The hybrid energy system is equipped with flywheel to store excess energy from the PV. HOMER software was employed to study the economic and environmental benefits of the system with flywheels energy storage for Makkah, Saudi Arabia. The analysis focused on the impact of utilizing flywheel on power generation, energy cost, and net present cost for certain configurations of hybrid system. Analyses on fuel consumption and carbon emission reductions for the system configurations were also presented in this paper. © 2015 Elsevier Ltd.


Ramli M.A.M.,King Abdulaziz University | Hiendro A.,University of Tanjungpura | Sedraoui K.,King Abdulaziz University | Twaha S.,Skyline Technical Services Ltd.
Renewable Energy | Year: 2015

Resource optimization is a major factor in the assessment of the effectiveness of renewable energy systems. Various methods have been utilized by different researchers in planning and sizing the grid-connected PV systems. This paper analyzes the optimal photovoltaic (PV) array and inverter sizes for a grid-connected PV system. Unmet load, excess electricity, fraction of renewable electricity, net present cost (NPC) and carbon dioxide (CO2) emissions percentage are considered in order to obtain optimal sizing of the grid-connected PV system. An optimum result, with unmet load and excess electricity of 0%, for serving electricity in Makkah, Saudi Arabia is achieved with the PV inverter size ratio of R=1 with minimized CO2 emissions. However, inverter size can be downsized to 68% of the PV nominal power to reduce the inverter cost, and hence decrease the total NPC of the system. © 2014 Elsevier Ltd.


Oramahi H.A.,University of Tanjungpura | Yoshimura T.,Kyoto University
Journal of Wood Science | Year: 2013

Antifungal and antitermitic activities of wood vinegar produced from Vitex pubescens were evaluated. Three kinds of wood vinegar were produced at three different pyrolysis temperatures, i.e. at 350, 400 and 450 °C. A PDA dilution method was employed to assay antifungal activity of the vinegars with a white-rot fungus Trametes versicolor and a brown-rot fungus Fomitopsis palustris. Termiticidal activity and repellent effect were evaluated by a no-choice test and a choice test with Reticulitermes speratus and Coptotermes formosanus. All wood vinegars exhibited antifungal activity against both fungi. Wood vinegar of 450 °C had the higher activity than those of 400 and 350 °C. It was assumed that acid component contributed to the increase in controlling the growth of fungal. The wood vinegar exhibited antitermite activity to both R. speratus and C. formosanus workers in the no-choice experiment. However, it needed relatively high concentration to obtain the perfect mortality. For instance, the wood vinegar of 10 % concentration was needed to achieve 100 % mortality against C. formosanus, whereas for R. speratus only 3 % of wood vinegar was required. In the direct-choice experiment, wood vinegar had a significantly repellent effect to both termites at the lowest treating concentration of 10 %. © 2013 The Japan Wood Research Society.


Hiendro A.,University of Tanjungpura
International Journal of Power Electronics and Drive Systems | Year: 2011

An investigation on multiple patterns for both odd and even number of switching angles in a three-phase selective harmonic elimination pulse width modulation (SHEPWM) inverter is presented. The switching patterns are examined and classified on the basis of the harmonic performance of the waveforms output from the inverter. Differential evolution algorithms are employed to calculate the optimum switching angles. Selected cases are verified experimentally by a digital signal processorbased hardware implementation. The experimental results show that all types of the patterns offer low harmonic distortions on the inverter output after filtering. However, one type gives better harmonic performance is identified.


Anwari M.,University of Technology Malaysia | Hiendro A.,University of Tanjungpura
IEEE Transactions on Energy Conversion | Year: 2010

This paper evaluates the influence of the unbalance factors in calculating total copper losses, efficiency, power factor, input power, output torque, peak currents, and derating factor of the motor operating under unbalanced voltage system. The complete definition for the voltage unbalance is using complex voltage-unbalance factor that consists of its magnitude and angle. A coefficient to determine either under- or overunbalance conditions is inserted. The analysis of the motor is performed using the method of symmetrical component, and MATLAB software is used to investigate the performance of the induction motor. The simulation results show that the International Electrotechnical Commission definition of the voltage unbalance combined with the coefficient of unbalance condition can be applied to evaluate total copper losses, input power, power factor, and total output torque precisely. However, the phase angle of the unbalance factor must be included for accurate prediction of peak current and peak copper losses of the phase windings and derating factor of the motor. © 2006 IEEE.


Said,University of Tanjungpura
Procedia Engineering | Year: 2015

Kapuas Hulu regency which is located in the easternmost of West Kalimantan province is still highly dependent on river transportation mode. Considering that multimodal transportation problems are lying at the level of respective services and ease of intermodal transfer, the performance of each mode should be evaluated for improvement. Based on the survey conducted to users of river transport modes, the following data have been obtained: 58% of users are private sector workers and 42% are civil servants, 85% of them make more than 2 million rupiah while another 15% earns between 1 to 2 million rupiah. With regard to travelers' age, it is dominated by people who are at the age of 30 to 40 years old, 33% of 40-50 years old and 7% of those between 20 to 30 years old. With regard to the purpose of the trip, as many as 61% use it to reach work place, 17% to visit their relatives and 6% with the aim of getting medical treatment. All respondents (100%) explain the reason for using river transportation mode is due to a very low level of accessibility (narrow and damaged roads) to reach their destination should they choose land transportation. The evaluation on the level of connectivity of transportation infrastructures provide us with three districts namely Semitau, Badau and South Putussibau having low level of connectivity between wharfs and terminals for passengers to change modes and continue their journeys. There are two districts whose high level of inter-connectivity infrastructure is high, i.e. Suhaid and North Putussibau districts where they have high levels of connectivity between wharf and terminal. And one district with a very high level of connectivity, namely Jongkong district, where the wharf and terminal are situated at one location thus making it easier for passengers to intermodal transfer. © 2015 The Authors. Published by Elsevier Ltd.


Hiendro A.,University of Tanjungpura | Kurnianto R.,University of Tanjungpura | Rajagukguk M.,University of Tanjungpura | Simanjuntak Y.M.,University of Tanjungpura | Junaidi,University of Tanjungpura
Energy | Year: 2013

Indonesia has considerable wind and solar energy potential, especially on onshore areas. However the wind and solar energy utilization is still low due to the high investment costs. This paper analyzes the potential use of wind turbine and PV (photovoltaic) for a PV/wind hybrid system in an onshore/remote location. NREL's (National Renewable Energy Laboratory) HOMER (Hybrid Optimization Model for Electric Renewable) software is used to perform the techno-economic feasibility of the PV/wind hybrid system. Simulations demonstrate that a 1-kW wind turbine has a capability to produce electricity of 496kWh/yr, while a PV panel at the same size generates electricity of 2079kW/yr. The results also show that wind turbine and battery are the most important components of the PV/wind hybrid system to meet demand loads at night hours. Since these two components give the greatest contributions to system costs, it is necessary to choose their best sizes to minimize the costs, but by taking into account that no loads are unmet. © 2013 Elsevier Ltd.

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