Pontianak, Indonesia
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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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.

People communities have an important role to play in biodiversity conservation. The ownership of land has often become a constraint on sustainable management of forest. The aim of this study was to explore the management system of forest land use in Dayak Desa in West Kalimantan, Indonesia. Data collection was undertaken through field observation, focus group discussion (FGD, and interviews with the community members. Dayak Desa has a several forest land use systems including tawang semilas, tawang sebesai, tawang mersibung, tawang sepayan, tawang serimbak and bukit rentap protection forest, which each system has its own function and utilization. Regardless of the system‟s differences, the forest land use systems have been supporting species diversity such as flora, fauna, and environmental services in Dayak Desa. This species diversity can support Dayak Desa community daily needs, regarding food, clothing, housing and other secondary needs. Forest utilization by Dayak Desa community is suitably paired to what can be produced by the land, which is equipped with their own rules. The role and the rule in managing, utilizing and protecting forest land use are Dayak Desa social capital. These are capital to acquire their rights to manage the forest. © 2016, Society for Indonesian Biodiversity. All Rights Reserved.

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.

Astiani D.,University of Tanjungpura
Biodiversitas | Year: 2016

Astiani D. 2016. Tropical peatland tree-species diversity altered by forest degradation. Biodiversitas 17: 102-109. Indonesian experienced relatively high deforestation and degradation. The forests degradation could bring the forests into a temporary or might be permanent destruction not only in forest vegetation density and structure, but also in species composition. A study had been carried out to examined the impact of peatland forests degradation on their species diversity composition in Ketapang,West Kalimantan peatland forest. Stratified random sampling was used to distinguished forest degradation class (low, intermediate and high degradation levels) based on the differences in spectra image and confirmed with field checking by measuring forest canopy opening to measure the degradation levels. Six to twelve of a 20x100 m plots were established to sample tree structure and composition distributed along peatland landscape. All trees species diameter >5 cm was registered an species identified. Results indicated that tree diversity was significantly reduce due to forest degradation, in low, intermediate, and high degraded forest were 82, 72, and 48 consecutively. Forest degradation not only resulted more than 50% of important species loss in high degraded peatland forest but also reducing ~40% tree abundance. Ten species were found in high degraded forest, e.g., Calophylum inophyllum, Cyathocalyx biovulatus, Neoscortechinia kingii, and Eugenia cerina, were not present in low degraded one. The species composition and abundance shifting due to forest degradation should be considered on peatland forest management to hinder permanent species loss. © Biodiversitas, 2012. All Rights Reserved.

Sitorus B.,University of Tanjungpura | Sukandar,Bandung Institute of Technology | Panjaitan S.D.,University of Tanjungpura
Energy Procedia | Year: 2013

Anaerobic digestion of a mix of fruit and vegetable wastes has been carried out in a 200-liter digester within 14 weeks. The wastes were anaerobically digested in an anaerobic digester at ambient temperature. The objective of this paper was to study the performance of the anaerobic process used mixed fruit vegetable wastes as substrates in a single stage fed-batch anaerobic digester for biogas production. The feed consisted of mixed fruit-vegetable wastes were collected from a traditional market in Pontianak city. The wastes were taken based on grab sampling method with a composition of ± 78 % vegetable waste, ± 4% tuber waste and ±18% fruit wastes. The total waste weight was 160 kg, mixed manually once in the feeding. Chemical analysis of initial waste and bioreactors slurry was performed using standard methods. The COD of the leacheate was in the range of 7.2-56.4 g/l, pH in the range of 5.3-6.8 and temperature of 28-46°C. The highest methane content in the biogas was 65% with the biogas flow of 20-40 ml/min. © 2013 The Authors. Published by Elsevier Ltd.

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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