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Medan, Indonesia

State University of Medan or UNIMED is a public university located in the city of Medan in North Sumatra, Indonesia. Wikipedia.

Simanjuntak J.P.,Universiti Sains Malaysia | Simanjuntak J.P.,State University of Medan | Zainal Z.A.,Universiti Sains Malaysia
Biomass and Bioenergy

This study aims to improve the heating value (HV) of gas produced during the gasification of sawdust using a new type of air-blown gasifier based on a two-compartment cylindrical fluidized bed. The gasification process is based on an internally circulating aerated fluidized bed (ICAFB) and consists of two individual zones; a gasification zone in the annulus and combustion zone in the draft tube. The annulus and draft tube are connected via orifices at the lower section of the draft tube wall to enable the solids to move from the annulus to the draft tube. Char, gasified residue, together with hot bed material move to the draft tube and combust to produce heat. Fluidization ratio (RQ) which is the ratio of air flow rate in the annulus (Qan) to the air flow rate in the draft tube (Qdt) together with equivalence ratio (ER) were used to control the temperature of the gasifier. The effects of ER on the temperature system stabilization, composition, HV of producer gas (PG) and gasifier performance were presented. ER ranges from 0.148 to 0.203 were used in this study. PG compositions of 3.13%, 2.28%, 25.8%, 8.2% and 22.48% for H2, O2, CO, CH4 and CO2 respectively with a HV of about 6.96 MJ m-3 were obtained at an ER of 0.185 and temperature of about 866°C. Compared with previous air-blown fluidized bed biomass gasification results, the ICAFB gasifier is capable of producing producer gas with higher CO and CH4 fractions. © 2015 Elsevier Ltd. Source

Syahputra H.,State University of Medan | Harjoko A.,University of Indonesia | Wardoyo R.,University of Indonesia | Pulungan R.,University of Indonesia
International Journal of Applied Engineering Research

The objective of the study was to improve the disparity map of a certain object in a stereo image. The steps required to complete this are first, to perform camera calibration in order to extract camera parameters, and then to use these parameters to rectify the stereo image. Second, to perform segmentation to separate the object from the background of the image. Separation of the object from the background was performed to produce a good disparity for the object. This had not been done in previous studies. Using segmentation, bias and error of stereo correspondence had been reduced, since the correspondence was focus on the intensity of the left and right objects in the stereo image. Using rectified and segmented stereo images, better disparity maps had been obtained. © Research India Publications. Source

Syamsiro M.,Janabadra University | Saptoadi H.,Gadjah Mada University | Tambunan B.H.,State University of Medan | Pambudi N.A.,State University of Semarang
Energy for Sustainable Development

Indonesia is the third largest producer of cocoa bean in the world. One of the residues produced after removal of the cocoa bean from the fruit is cocoa pod husk (CPH). The objective of this work was to assess the use of CPH as a renewable energy source. CPH was sun-dried, crushed, and screened to obtain a particle size of less than 1. mm. Five grams mixture of CPH and binder in the proportion of 70% and 30% by weight respectively was pelletized and dried at 50 °C for 5. hours. Carbonization was performed at 400 °C for 2. hours. The results show that CPH has a high heating value of 17.0. MJ/kg. The air flow rate and fuel composition significantly affected the burning time and CO emission factor. The increase of carbonized CPH portion in the fuel increased the burning time of the pellet. The increase of air flow rate and carbonized CPH portion also increased the emission factor of CO. © 2011 International Energy Initiative. Source

Molliq R.Y.,State University of Medan | Noorani M.S.M.,National University of Malaysia
International Journal of Computational Methods

This paper presents a new reliable modification of the variational iteration method (MoVIM). An enlarged interval of convergence region of series solutions is obtained by inserting a nonzero auxiliary parameter (h) into the correction functional of variational iteration method. Approximate analytical solutions for some examples of nonlinear problems are obtained using variational iteration method. Comparison with the exact solution, Runge-Kutta method 4, and also another modified variational iteration method has shown that MoVIM is an accurate method for solving nonlinear problems. © 2013 World Scientific Publishing Company. Source

Luthan P.L.A.,State University of Medan
IOP Conference Series: Materials Science and Engineering

Mandailing is one of bataknesse ethnic in North Sumatera which belong to strong to hold the customs and traditions Mandailing culture which reflected in the parts of the traditional houses. However rapidly the construction modern house make possibility the traditional house which enriched with culture value will be extinct.This studyto identify the value of culture and architecture typology of traditional house in Mandailing Natal North Sumatera. A case study using phenomenology method that is recording and serving the phenomenon which found in field as evidence that include existing condition from building. The finding show that 1) religion system or reliance in the front of location election, ornamentation orientation, construction system and room arrangement, 2) kinship system in the front of room organization, room amount and the completeness, 3) live philosophy found in shape and room arrangement which can accomodate all activity, 4) leadership system in the front of ornamentation shape and the meaning, pillar shape, house size vertically, and 5) social system in the front of roof shape, the used of decoration style and room arrangement. Architecture typology of Mandailing house dug from the shape and the construction, room arrangement, and roof shape. © Published under licence by IOP Publishing Ltd. Source

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