cover
Article Per Year (5 Year)
All
Home Page
OAI Link
Editorial Team
Contact
Reviewer
Google Scholar
Contact Name
-
Contact Email
-
Phone
-
Journal Mail Official
-
Editorial Address
-
Location
Kota adm. jakarta selatan,
Dki jakarta
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 8 Documents
 1 
Search results for , issue " Vol 38, No 3 (2015)" : 8 Documents clear
STRUCTURE AND HARDNESS CHARACTERISTICS OF 50Cr-50Al COATING PREPARED BY A MECHANICAL ALLOYING TECHNIQUE: EFFECTS OF HEAT TREATMENT TEMPERATURE Sudiro, Toto; Sebayang, Perdamean
Teknologi Indonesia Vol 38, No 3 (2015)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jti.v38i3.247

Abstract

In the present work, a mechanical alloying technique was used to prepare 50Cr-50Al (in atomic, at %) coating on the surface of low carbon steel. The coated samples were then annealed in a vacuum at elevated temperatures of 600, 700, 800, and 900C for 2h, separately. The effects of annealing temperature on the structure characteristic of 50Cr-50Al coating were studied by XRD and SEM-EDX, and coating hardness was measured by micro-Vickers hardness test. The results showed that the annealing process led to the formation of inter-metallic phases and interdiffusion of Fe element from the substrate and Cr, Al elements from the coating, depending on annealing temperature. As annealing temperature increased to 900C, however, X-ray diffraction analysis indicated the formation of Al2O3. Meanwhile, the hardness of cross-sectional of coating increased after annealing at 600C. The coating hardness decreased as annealing temperatures increased.
ENDOPHYTES RHIZOBIA BACTERIA, ISOLATED FROM ACACIA MANGIUM, ITS POTENSIAL TO SUPPORT THE GROWTH OF SOYBEAN. Sukiman, Harmastini
Teknologi Indonesia Vol 38, No 3 (2015)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jti.v38i3.225

Abstract

Acacia mangium is a legume tree species which has high tolerance with many different conditions and dry area. Aim of this research is to study the possibility of cross inoculation of rhizobium endophytic bacteria isolated from Acacia mangium to soybean plant and to find out the best combination of inoculants to develop biofertilizers quality. Isolation of rhizobium endophytes from Acacia mangium analysed using 16S rRNA methods identified that the bacteria belonged to Rhizobia tropici. Results showed that single inoculation of endophytic bacteria can produce soybean seed up to 19.71 gram which was slightly higher compared with control plants of 16.0 gram and chemical fertilizer treatment plants of 18.0 gram per plant. Meanwhile, Rhizobium inoculation still gave the best production of soybean; that is 28 gram per plant. Moreover, stress test results showed that the bacteria could adapt better with acidity and salinity, including UV exposure and cold condition, yet were unable to adapt with hightemperature and oxidative condition.
PRODUCTION OF WOOD CHARCOAL AS BIO-REDUCTOR IN BLAST FURNACE Isnugroho, Kusno; candra, david
Teknologi Indonesia Vol 38, No 3 (2015)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jti.v38i3.242

Abstract

A study on bio-reducer using lamtoro and rubber wood raw materials had been conducted. This study used carbonizing furnace made from mild-steel which was equipped with absorber to reduce emitting exhaust gas during process. The absorber used came from activated zeolite inserted with TiO2. Carbonizing process was conducted in 700C, 800C, and 900C temperatures. The produced results, both from lamtoro and rubber wood raw materials, underwent reduction along with increasing carbonizing temperatures. Yields from rubber wood at 700C, 800C, and 900C were 23.12%, 21.32%, 20.26%, respectively, and yields from lamtoro wood at 700C, 800C, and 900C were 26.51%, 25.13%, and 24.12%, respectively. Ultimate and proximate test using ASTM D.3174, ASTM D.3173, ASTM D.3175, ASTM D.5373 and ASTM D.4239 showed that bio-reducer product in form of charcoal made from lamtoro and rubber wood had fulfilled specifications as a reducer in iron ore processing. Test result of emitting exhaust gas showed reduced CO and NOx gases during carbonizing process.
CHEMICAL COMPOSITION OF ESSENTIAL OILS FROM LEAVES AND SEEDS AND ARYLS OF KALAK PACUNG(Horsfieldia subglobosa) (Myristicaceae) Praptiwi, - -
Teknologi Indonesia Vol 38, No 3 (2015)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jti.v38i3.236

Abstract

ABSTRACT The aim of the study was to determine the chemical composition of the essential oil of kalak pacung (Horsfieldia subglobosa) from different part of the plant (leaves and seeds and aryl). The essential oil was obtained by hydro-distillation, while its chemical compounds were separated and identified by gas chromarography-mass spectrometry (GS-MS). GC-MS analysis of the seed and aryl oil showed that it consisted of 58 compounds, 50 compounds of which were identified, representing 86,56% of the whole. Meanwhile, the leaf essential oil consisted of 75 compounds, with 61 compounds identified represented 98,35%. The main compounds of seed and aryl essential oil were (-) spathulenol type 2 (9.45%), naphtalene type 1 (7.40%) and type 2 (7.40%). The compounds of leaf oil with concentration more than 5% were isocaryophyllene (13.29%), a-Copaene (6.62%), and naphthalene (6.88%).
THE EFFECT OF DIGITAL PWM STEADY STATE RESPONSE ON THE SPEED OF BLDC MOTOR Rahmayanti, Rifa; Utomo, Sapdo; Saputra, Hendri Maja
Teknologi Indonesia Vol 38, No 3 (2015)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jti.v38i3.244

Abstract

This research aims to analyze the work system of a brushless DC (BLDC) motor speed driver. The motor is controlled by a driver which receives speed command signal from a microcontroller. Effect of digital Pulse Width Modulation (PWM) command signal on the speed response of the motor is investigated by changing duty ratio from 30% to 100% and frequency between 500Hz?100kHz. Each speed response is compared against the speed response of the corresponding analog command signal. From the experimental results, it can be concluded that larger switching frequency provides smaller steady state error and smaller standard deviation in the speed response. More specifically, for the BLDC motor used in the experiments, steady state error of 5% rotational speed can be achieved only by a digital PWM command signal the duty cycle ratio of which is larger than 60% and the frequency of which is larger than 1 kHz.
ANALYSIS OF BRAKING DYNAMICS USING LINEARIZED QUARTER VEHICLE MODEL rozaqi, latif; Rijanto, Estiko
Teknologi Indonesia Vol 38, No 3 (2015)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jti.v38i3.237

Abstract

A deep understanding in dynamical characteristics of braking systems is very important in designing an appropriate control system to be applied in a vehicle. This paper examines the braking system dynamics of a car using Quarter Vehicle Model (QVM). In order to facilitate the analysis, a linear model has been derived from a nonlinear QVM. The dynamical characteristics of braking are analyzed using state space equation and then explored through numerical simulation. The result is then compared with nonlinear Euler and 4th order Runge-Kutta methods. In the numerical simulation, the dynamic model is given some different braking inputs and different road conditions to notice the dynamical response of the model. This study learns that applying a sudden braking torque will cause the slip response to move to locked condition too fast. By reducing the input gradient by 48.6673%, 14.3875% improvement on longitudinal speed deceleration will be gained. Therefore, applying braking torque gradually will increase braking effectivity. Moreover, dry asphalt gives the best response compared to both dry concrete and wet asphalt because it gives 9.1940% more effective longitudinal speed deceleration.
FABRICATION AND CHARACTERIZATION OF SOFT COMPOSITE MAGNET BaFe12O19 - SiO2 ginting, masno; Sebayang, Perdamean; N, Nasrudin M
Teknologi Indonesia Vol 38, No 3 (2015)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (16.054 KB) | DOI: 10.14203/jti.v38i3.249

Abstract

Preparation and characterization of soft magnetic BaFe12O19?SiO2 has been successfully carried out by mixing BaFe12O19 powder with SiO2 powder. The ratios of Ba Fe12O19/SiO2 used were 100:0, 80:20, 70:30, 60:40, and 50:50 by percent weight. Mixing process was carried out with a dry milling method using planetary ball mill (PBM) for 48 hours. The mixed powder then was pressed at 35 kgf/cm2 on anisotrophy condition to produce pellets with a diameter of 12 mm and 3?5 mm thicknesses. The pellets then were sintered at temperatures of 600, 650, 700, 750, and 800C, each of which was held for 2 hours. The XRD measurement showed that there were three phases appearing, i.e. BaFe12O19 as the majority, and SiO2 and Fe3O4 as minorities. Meanwhile, the result from SEM measurement showed that the grain size was less than 1 ?m. The best magnetic properties were obtained for the composition of 80 wt% BaFe12O19 and 20 wt% SiO2 with sintering temperature at 800C, where the coercivity value (Hc), remanence (Br) and maximum energy product (BHmax) were 1.656 kOe, 0.81 kG, and 0.414 MGOe, respectively.
INVESTIGATION OF THE PERFORMANCE OF SINGLE AND MULTI-CELL STACKS OF PEMFC -, Indriyati; Irmawati, Yuyun; Subhan, Achmad
Teknologi Indonesia Vol 38, No 3 (2015)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (16.054 KB) | DOI: 10.14203/jti.v38i3.132

Abstract

The performance of single, 3-cell, and 5-cell stacks of PEMFC have been experimentally investigated. Emphasiswas placed on the effect of different operating condition including hydrogen/oxygen flow rate and pressure on thePEMFC performance through analysis of polarization curves. The results showed that flow rate slightly affected theperformance of single-cell PEMFC at higher current densities whereas no significant differences were observed atlower current densities. Similar curve patterns were obtained when testing the single and 3-cell PEMFC stacks withvariation of backpressure. Increasing backpressure gives positive effect on the stack performance due to improvingthe reaction at the electrodes. However, this behavior did not occur on 5-cell PEMFC stack the performance of which decreased as the backpressure increased from 5 to 10 psi due to increasing water production in the cathode. In this study, the highest operational (at voltage of 0.6 V) current density of 85.6 mA/cm2 was obtained from 3-cell stack with flow rate of H2/O2 and backpressure 800/1,000 ml/min and 10 psi, respectively. This good performanceis more evident when the 3-cell stack was evaluated over a quite long operation time. After decreasing gradually at the first 50 min operation, the performance of 3-cell stack of PEMFC remained stable up to 200 min, while it fluctuated in 5-cell stack due to poor water management. This study confirms that the performance of PEMFC stack is highly influenced by the number of cell and operating condition, and the performance of PEMFC stack is not linear as function of number of cell.

Page 1 of 1 | Total Record : 8

 1 

Filter by Year

2015 2015


Reset
Filter By Issues
All Issue Vol 41, No 1 (2018) Vol 40, No 2 (2017) Vol 40, No 1 (2017) Vol 39, No 3 (2016) Vol 39, No 2 (2016) Vol 39, No 1 (2016) Vol 38, No 3 (2015) Vol 38, No 2 (2015) Vol 38, No 1 (2015) Vol 37, No 3 (2014) Vol 37, No 2 (2014) Vol 37, No 1 (2014) Vol 36, No 3 (2013) Vol 36, No 2 (2013) Vol 36, No 1 (2013) Vol 35, No 3 (2012) Vol 35, No 2 (2012) Vol 35, No 1 (2012) Vol 34 (2011) Vol 33, No 2 (2010) Vol 33, No 1 (2010) Vol 32, No 2 (2009) Vol 32, No 1 (2009) More Issue