Hasanuddin University is one of the biggest stated-owned universities in Indonesia, based in Makassar, the capital of South Sulawesi province. The university was established in 1956, and named after Sultan Hasanuddin, a King of Gowa Kingdom. Before the official launching by the first vice President of Indonesia, Mohammad Hatta, there had been in Makassar a faculty of economy of University of Indonesia,centered in Jakarta. This faculty became the seed of Hasanuddin University. Wikipedia.
Syafaruddin,Hasanuddin University |
Karatepe E.,Ege University |
Hiyama T.,Kumamoto University
Energy Conversion and Management | Year: 2012
Mismatching losses reduction of photovoltaic (PV) array has been intensively discussed through the increasing penetration of residential and commercial PV systems. Many causes of mismatching losses have been identified and plenty of proposed methods to solve this problem have been recently proposed. This paper deals with reducing method of mismatching losses due to the non-uniform irradiance conditions. It is well-known that a certain number of multiple peaks occur on the power-voltage curve as the number of PV modules in one-string increases under non-uniform operating conditions. Since the conventional control method only drives the operating points of PV system to the local maxima close to open circuit voltage, only small portion of power can be extracted from the PV system. In this study, a radial basis function neural network (RBF-ANN) based intelligent control method is utilized to map the global operating voltage and non-irradiance operating condition in string and central based MPPT systems. The proposed method has been tested on 10 × 3 (2.2 kW), 15 × 3 (2.5 kW) and 20 × 3 (3.3 kW) of series-parallel PV array configuration under random-shaded and continuous-shaded patterns. The proposed method is compared with the ideal case and conventional method through a simple power-voltage curve of PV arrays. The simulation results show that there are significant increases of about 30-60% of the extracted power in one operating condition when the proposed method is able to shift the operating voltage of modules to their optimum voltages. © 2012 Elsevier Ltd. All rights reserved.
Jalaluddin,Saga University |
Jalaluddin,Hasanuddin University |
Miyara A.,Saga University
Applied Thermal Engineering | Year: 2012
The thermal performances of several types of vertical ground heat exchangers (GHEs) for ground source heat pump system have been investigated with different operation mode. Short time period of operation, discontinuous of 6 and 12 h operations in a day, and continuous operation modes were applied in the GHE system. The short time period of operation includes discontinuous 2 h operation in cooling mode and alternative operation mode with operating the GHE in cooling process and heating process to provide hot water supply. The models of three types of vertical GHEs, including U-tube, double-tube, and multi-tube GHEs, were built and simulated using the commercial computational fluid dynamics software FLUENT. The heat exchange rates of the GHEs have been investigated. The numerical results show the reasonable agreement with the experimental results. The off-time period in the discontinuous operation and extracting heat from the ground in the heating process in the alternative operation mode contributed significantly to the increasing the heat exchange rate. Operating the GHEs with different operation mode shows the different characteristic in their heat exchange rates. It can be constructive information for design of the GHE system in practical engineering. © 2011 Elsevier Ltd. All rights reserved.
Sutresman O.S.,Hasanuddin University
International Journal of Applied Engineering Research | Year: 2014
The objective of this buckling simulation is to analyze the increase of strength on a HS- 75 profile with the addition of a diaphragm plate and to gain an understanding of the diaphragm plate analytical optimization. The HS-75 was observed in three different conditions. The first condition is analyzing the HS-75 without any stiffener plate attach. These condition is by attaching one diaphragm plate on the middle of the HS-75 beam, and the last observed object is a HS-75 beam with three diaphragm plate attach on certain places along the beam. The simulation of HS-75 is important to predict the actual strength or some other properties such as strain, deflection or deformation. Finite element is used to simulate the HS-75. First is preparing the simulation to produce the HS-75 using the Ansys workbench software. The HS-75 properties should be attached, the Young modulus value, the Poison Ratio value and the Tensile Ultimate Strength value. The HS-75 beam has a length of 1800mm and a plate thickness of 0.08mm. Second is dividing HS-75 insmall parts as the beam mesh. Next step is attaching the loads workout on the beam. The last process is simulating the product by analyzing the directional deformation and the total deformation. FEM buckling static stress analysis is also simulated on three different beam conditions. The results show that at a maximum buckling load of 20.000N, the HS-75 profile mild steel material with a three diaphragms attached deflect as big as 14mm. While the profile withone diaphragm attached deflect about 15mm. For the profile without any diaphragm attached has a deflection of 20mm. This is an indication that the profile with a three diaphragm attached was able to with stand the maximum load greater than either the profile attached with one diaphragm or the profile without any diaphragm attached. © Research India Publications.
Sahide M.A.K.,University of Gottingen |
Sahide M.A.K.,Hasanuddin University |
Giessen L.,University of Gottingen
Land Use Policy | Year: 2015
Tropical forests in Indonesia are subject to major transformation processes from native forests to other land uses, including rubber agroforestry as well as rubber and oil palm plantation systems. Using content analysis of policy documents, this paper aims at (i) analysing the formal administrative responsibilities related to the four rainforest transformation systems and (ii) based on the informal motives of the competing bureaucracies involved generating hypotheses on their future course of action and related research. We find that based on the legal and political land use application, Indonesian tropical rainforests may fall into six categories of land use. They may be situated in both, within the forest area and land outside of the forest area in so-called title forests, even though there is a though political debate about forest area category's jurisdiction confirmation. The Ministry of Forestry, the National Land Agency, and regional governments are identified as the core bureaucracies responsible in both forest area and title forest. The Ministry of Agriculture only has responsibilities in title forests. A number of secondary bureaucracies also steering forest transformation are identified. Formal responsibilities of these bureaucracies are highly complex and fragmented regarding the tasks of forest regulation, forest administration, forest management, forest protection, issuing forest management rights, issuing land rights, regulating and administering timber product, issuing licence, and regulating the commodity. Indonesian tropical rainforest is found to potentially transform into other land uses through seven ways: (i) releasing certain area from forest area, (ii) using forest area for non-forestry purposes (e.g. palm oil plantation), (iii) maximising production forests for logging, (iv) developing community forest schemes in forest area, (v) developing plantation and agroforestry in title forest (vi) taking advantage from waste land, and (vii) steering back to native forest. The intersection of responsibilities in steering rainforest transformation has created contestation between the bureaucracies involved. We conclude that the main conflict of interests runs between the core bureaucracies in this transformation, i.e. the Ministry of Forestry, the National Land Agency, and regional governments. The authors conclude with hypotheses on future actions of such bureaucracies in light of national and international influences on rainforest transformation systems. The central hypothesis contends that both core and secondary bureaucracies have conflicting interests over all four types of tropical rainforest transformation due to the areas of overlapping responsibility. © 2014 Elsevier Ltd.
Yunus B.,Hasanuddin University
Imaging Science in Dentistry | Year: 2011
Purpose: This study was performed to evaluate the changes of jaw bone density around the dental implant after placement using computed tomography scan (CT-Scan). Materials and Methods: This retrospective study consisted of 30 patients who had lost 1 posterior tooth in maxilla or mandible and installed dental implant. The patients took CT-Scan before and after implant placement. Hounsfield Unit (HU) was measured around the implants and evaluated the difference of HU before and after implant installation. Results: The mean HU of jaw bone was 542.436 HU and 764.9 HU before and after implant placement, respectively (p<0.05). The means HUs for male were 632.3 HU and 932.2 HU and those for female 478.2 HU and 645.5 HU before and after implant placement, respectively (p<0.05). Also, the jaw bone with lower density needed longer period for implant procedure and the increased change of HU of jaw bone was less in the cases which needed longer period for osseointegration. Conclusion: CT-Scan could be used to assess the change of bone density around dental implants. Bone density around dental implant was increased after placement. The increased rate of bone density could be determined by the quality of jaw bone before implant placement. © 2011 by Korean Academy of Oral and Maxillofacial Radiology.