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INDONESIA
Teknologi Indonesia
Published by Lembaga Ilmu Pengetahuan Indonesia
ISSN : 01261533     EISSN : 23031913     DOI : -
Core Subject : Science,
Computer Science & IT
JTI is a journal in the Departement of Engineering Sciences - Indonesian Institute of Sciences (LIPI). JTI has policy to publish a new and original research paper or a review paper in The scope of Technology. JTI publishes two issues per year. The journal has been registered with printed-ISSN number as 0126-1533 and electronic ISSN number as 2303-1913.
Arjuna Subject : -
Articles 6 Documents
 1 
Search results for , issue " Vol 35, No 3 (2012)" : 6 Documents clear
Method of Delineate of the ITCZ for the ITCZ Monitoring System Related to Early Season Yulihastin, Erma; Fathrio, Ibnu; Cholianawati, Nani
Teknologi Indonesia Vol 35, No 3 (2012)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (16.051 KB) | DOI: 10.14203/jti.v35i3.190

Abstract

The ITCZ has dominant of role to control atmospheric tropic-equator that were described clearly by satellite band of cloud and rain from west to east around the world as a part of Hadley circulation. Study the ITCZ phenomenon is very important because monsoon onset can be identifi ed by ITCZ jump to the northern or southern relative to the equator. Moreover, understand the ITCZ dynamic is keys to understand other phenomena such as ElNino Southern Oscillation (ENSO), Indian Ocean Dipole Mode (IODM), Madden Julian Oscillation (MJO), monsoon circulation, and Tropical Cyclone (TC). Other phenomena will disturb to the ITCZ. Study the ITCZ also important to predict rain and extreme event related to natural disaster such as fl ood, slide, dryness using prediction model. In this applied research, we develop monitoring system of the ITCZ based on MTSAT satellite observation to define early season over IMC (IMC). Research outputs are early season information and real time of ITCZ position on LAPAN website. The ITCZ position will always updated by real time. The information used to operational concern at LAPAN and researcher at other institutes for investigate early season predict to raise paddy fi eld productivity and to encourage development of early warning natural disaster system. Results show that jumping of the ITCZ positioncan be used to identify early season over IMC by global scale. Whereas in regional scale, jumping of the ITCZ appropriate to insitu observation to detect early season for monsoonal, equatorial, and local rain type. Moreover, time series profi le of the ITCZ has symmetry pattern with zonal wind over southern IMC.
Annual Migration of Monsoon Over Indonesia Maritime Continent Based on OLR Data Yulihastin, Erma; Hermawan, Eddy
Teknologi Indonesia Vol 35, No 3 (2012)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jti.v35i3.191

Abstract

Annual migration of monsoon over Indonesia Maritime Continent (IMC) were analysed by Outgoing Longwave Radiation (OLR) data. Global climatology of NCEP/NCAR Reanalysis II (National Center for EnvironmentalPrediction/National Center for Atmospheric Research) namely OLR, wind, and precipitable water were derived from 1975 to 2010 which have 2,5o spatial degree resolution. The results showed those the annual migration were described by annual cycle of OLR<220 W/m2 occurred almost over IMC related to the wet periods (DJF). Whereas, OLR>240 W/m2 occurred only over south of IMC (3-9o S) related to the dry periods (JJA). Zonal variation of OLR showed annual cycle occured in areas of 2-10oS and 5-10oN, respectively. On the other hand, meridional variation described annual cycle in areas 90-120o E and 90-150, which respectively mentioned as area I and area II. Annual cycle of OLR in area I was symmetry with area II. Also, in areas I and II, parameters of OLR and precipitable waterwere symmetry each other. Signifi cants anticorrelation between OLR and precipitable water were -0.89 and -0.95 in area I and II, respectively.
Performance Evaluation of Friction Materials for Railway Brake Application Using Oil Palm Empty Fruit Bunch Fiber as Reinforcement Alam, H.S.; Puja, IGN W.; Suratman, R.
Teknologi Indonesia Vol 35, No 3 (2012)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (16.054 KB) | DOI: 10.14203/jti.v35i3.192

Abstract

Performance of friction material for railway brake applications using oil palm empty fruit bunches (OPEFB) fibers as reinforcement has been evaluated using extension evaluation method (EEM) refers to the technical specifications of PT. KAI. Characterizations of two commercial samples, K1 and K2, were used as a reference and a preliminary study to develop railway brake materials using OPEFB fi bers. Six samples of non-commercial brake that use OPEFB fi bers, T1 to T6, were made with different compositions and then tested with samples of K1 and K2. The results of the tests were used as input of evaluation to select the best samples of brake material. Base on the results of evaluation using EEM, samples T1 and T4, which used OPEFB fi bers as reinforcement ranked above the commercial sample K2 which used synthetic fi bers, so it can be concluded that OPEFB fi ber as reinforcement for railway brakes can improve the physical and mechanical properties, have excellent performance, friendly to the environment and is expected to replace synthetic fibers.
Design and Analysis of the Prototype of Pico Hydro Scale Submersible Type Turbine-Generator for Flat Flow River Application Subekti, Ridwan Arief; Susatyo, Anjar; Irasari, Pudji
Teknologi Indonesia Vol 35, No 3 (2012)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jti.v35i3.188

Abstract

This paper discusses the design and analysis of prototype of submersible type turbine-generator for fl at fl ow river application. 500 W pico hydro turbine with the net head of 1 m was used. The type of turbine used was ofPropeller type with the blade profi le shape of airfoil NACA 6412 and the runner blade number of 6 pieces. Turbine and generator was aligned on one shaft (direct coupled) so that the construction was simple. The generator usedwas of permanent magnet generator type of 500 W, 500 rpm, 1 phase, 50Hz, 220 V. The turbine-generator unit was then tested in one of Kebun Raya Cibodas channels. The test was conducted at varied heads and constant loadscomprised of 5 x 100 W lights. The test results presented in the form of head vs. speed and head vs. power graphs show that the system could only have effi ciency of 19.98%.
Anatomical and Physiological Characteristics of Reclamation Plant on the Post-Mining Land in Riding Panjang, Bangka Nurtjahya, Eddy; Juairiah, Lina
Teknologi Indonesia Vol 35, No 3 (2012)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jti.v35i3.268

Abstract

Tin mining leaves disturbed land with sandy texture, damages natural drainage and habitats, and very low water holding capacity. The enrichment of species selection criteria for revegetating tin tailing with anatomical and physiological characters is needed to facilitate decision maker to select local species suitable for revegetation and to meet the economical need of the local people in post tin mining era. Besides exotic species, a handful of local tree species was planted recently. The need of more local species is especially needed to support biodiversity in mined land. Study of some leaf anatomical and root physiological characters of twelve months seedlings of leban(Vitex pinnata L-Verbenaceae) and ubak (Syzygium grande (Wight) Walp.Myrtaceae) planted in unmined land and tin-mined land in Bangka Island was conducted using wholemount and paraffi n methods. The fi ndings showedthat anatomical and physiological parameters of V. pinnata are more signifi cant than those of S. grande. Therefore, V. pinnata is more adaptive grown on tin tailing than S. grande.
Investigation of Hydrogen Flow Uniformity in a Serpentine Separator Plate of a PEMFC Using Computational Fluid Dynamics Simulation Wahyu, Haifa; Oemry, Achiar; Djunaedi, Imam
Teknologi Indonesia Vol 35, No 3 (2012)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jti.v35i3.189

Abstract

This paper presents an investigation on the uniformity of hydrogen flow in a separator plate of a Polymer Electrolyte Membrane Fuel Cell (PEMFC). Hydrogen is the main reactant of a PEMFC that fl ows within the separatorplate and into the MEA. Separator plates have fl ow fi eld lay out which is the determining factor for the uniform distribution of the gas. The separator plates used in this study has the shape of serpentine fl ow fi eld, taken from a 200 Watt PEMFC stack. The fl ow of hydrogen gas is simulated within the separator plate to analyse the pressure and velocity distribution which has a correlation with the fl ow fi eld design. The objective of the study is to determine flow uniformity within the separator plates by increasing the hydrogen gas pressure from 1 bar up to 3 bars. Although flow distributions for the three cases are similar and quite uniform, but the velocity in the plates was reduced when the hydrogen pressure was increased. This is due to the backpressure occurs as a result of resistance from the flow field and also the gas diffusion layer governing a fuel cell. From the experiments on the characterization of fuel cell stack, the best practice is to maintain the inlet pressure at low level, that is around 1 bar, which is in agreement with the current simulation results. The fl ow was simulated using commercial CFD package by employing Navier-Stokes method which is the governing equation of the computational fl uid dynamics (CFD) application. The results are compared to the steady output without random differences of an experimental running of the fuel cell stack.

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