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.
Roslinda E.,University of Tanjungpura
Biodiversitas | Year: 2016
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.
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.