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Teknologi Indonesia

JTI
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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 163 Documents

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THE USE OF AN IMPORTED NdFeB MAGNET IN DESIGNING AND FABRICATING AXIAL FlUX PERMANET MAGNET GENERATOR Ginting, Masno; Sebayang, Perdamean; Siregar, Elfrida
Teknologi Indonesia Vol 38, No 1 (2015)
Publisher : LIPI Press

Axial flux generator that consists of two rotors and one stator has been engineered. The rotor consists of eightimported NdFeB permanent magnets with 6 x 4 x 0.7 cm dimension and remanant (Br) 1.1 Tesla. The stator with 300 mm diameter consists of a spoils with 80 mm diameter with 400 coils, and the diameter of copper wire is 0.5mm, while the number of the spoil is varied. In this paper, the design and analysis for generator model has been done using 3DS MAX 2014 and Microsoft Visual Basic 2010 Express software, so that the right number of spoils in producing the optimal out put voltage (Erms) is obtained. From the experiment and simulation of axial flux permanent magnet (AFPM) generator, it has been obtained that there is correlation between the rotational speed (Vr in rpm) and the frequency and the voltage (Erms), which are given by equations i.e. frequency = 0.0667 Vr - 0.0001 and Erms = 0.4027 Vr + 3.2619, repectively. Meanwhile, the relation of the rotational speed and the number of spoils (Ns) to the outout voltage (Erms) is given by Erms = 0.0695 Ns Vr.

ALPHA GLUCOSIDASE INHIBITORY ACTIVITY FROM Syzigium sp. Saraswaty, Vienna
Teknologi Indonesia Vol 33, No 1 (2010)
Publisher : LIPI Press

Objective of this research is to investigate alpha glucosidase inhibitory activity from Syzygium species. 20 of syzygium species was extracted using 70% ethanol and evaporated to be tested for its alpha glucosidase inhibitory activity and resulted that S. cumini and S. syzygioides have a high alpha glucosidase inhibitory activity with IC50 value was 8.71 ppm and 7.48 ppm respectively. Further investigation on some parts of S. cumini plant showed that the highest activity was found in the cortex with IC50 value of 0.45 ppm. Fractionation of ethanolic extract of S. cumini cortex using n- hexane, dichloromethane, ethyl acetate, n-buthanol and water resulted that the highest yield was in water fraction with IC50 value of 8.15 ppm. Phytochemical screening assay showed that ethanolic extract of S. cumini cortex contained terpenoid, phenol, saponin, tannin and fl avonoid.

THE IMPLEMENTATION OF PARTICIPATORY ERGONOMICS PROGRAM IN THE EFFORTS TO IMPROVE CONCERN TOWARDS WORKPLACE ACCIDENTS (CASE STUDY OF SHOE INDUSTRY) Sukapto, Paulus; D, Harjoto; Yumanto, Yumanto; Marbun, Romy
Teknologi Indonesia Vol 39, No 3 (2016)
Publisher : LIPI Press

Participatory ergonomics (PE) is an effective and efficient method to improve the employees concern towards workplace accidents in order to work more productively. The success of PE is determined by participation, organization, ergonomic methods and tools, as well as job design concept. The implementation of this method was conducted in the Upper Production Department (the division producing the top part of shoes) which consists of seven work stations. Each work station is measured concerning its risk score (RS). The measurement result shows that Dering and Pouching Stations have RS of more than the determined limit, therefore they need an improvement. The improvement results are protector for Pouching Machine and material clamp for Dering Machine.

DESIGN OF AN ADAPTIVE INTELLIGENT CONTROLLER IN A SEMI-ACTIVE SUSPENSION SYSTEMS Turnip, Arjon; Soetraprawata, Demi; Hariyadi, -; Kusumandari, Dwi Esti
Teknologi Indonesia Vol 36, No 1 (2013)
Publisher : LIPI Press

In this paper, a semi-active control law consists of two tuneable parameters that are given as the function of the running conditions of the vehicle and an adaptive intelligent controller (AIC) is proposed to obtain the best compromise among confl icting performance indices pertaining to the vehicle suspension system. The proposed AIC method is developed based on the frequency regions. The obtained result indicates that a semi-active suspension system based AIC has a signifi cant potential in improving the ride comfort and the road holding.

Assessment of Biomass Feedstock Availability and Bio-Refinery Sites Selection for Cellulosic Ethanol and Bio-Methane Production (Case Study: Palm Oil Processing Waste as Bio-Refinery Feedstock in East Kalimantan , Indonesia) Andriana, Yusuf
Teknologi Indonesia Vol 37, No 3 (2014)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jti.v37i3.228

This study discussed about feedstock availability and bio-refinery sites selection for palm-oil-processingwaste- to-bio-energy industry. A case study was based on existing palm oil millings in East Kalimantan province.The objectives of this research were (1) to assess the availability of palm oil processing waste as feedstock of bio-refinery turning into palm-oil-processing-waste-to-bio-energy industry in East Kalimantan and (2) to select bio-refinery sites in East Kalimantan. Time series analysis was used to assess feedstock availability of palm oil processing waste and Analytical Hierarchy Process (AHP) was used to select bio-refinery sites in East Kalimantan. The result of this research showed that the availability volumes of palm oil waste as raw material for bio-refinery at palm oil processing industry were predicted as many as 2,645,736 tons of empty fruit bunches, 1,814,238 tons palm oil fiber, 806,328 tons palm kernel shell, and 7,345,144 tons palm oil milling effluent in 2022. The appropriate bio-refinery sites for palm-oil-processing-waste-to-bio-energy industry in East Kalimantan based on experts judgment using Analytical Hierarchy Process was Kutai Kartanegara Regency.

SAGO STARCH AS FERMENTATION MEDIUM FOR PRODUCTION OF AND SUBSTRATE FOR CARBOHYDRATE ENZYMES Karossi, A.T.
Teknologi Indonesia Vol 32, No 2 (2009)
Publisher : LIPI Press

It is well known that sago starch extracted from sago palm (Metroxylon sp.) is abundantly available especially in eastern part of Indonesia. On the other hand, amylases and related enzymes are recognized as the most important industrial enzymes, specifically in the field of food industries. Therefore, fermentation experiments were carried out to utilize sago starch as medium component to produce extracellular alpha amylase and glucoamylase as well as glucose isomerase, which is the later being an intracellular enzyme. Aspergillus oryzae was selected fermenting microorganism to produce the extracellular alpha amylase and intracellular glucose isomerase, while Rhizopus oryzae was for producing extracellular glucoamylase. The investigation included optimum fermentation process condition for enzymes production, both in Ehrlenmeyer shaken flasks and stirred tank fermentors, then was followed by isolation with ammonium sulfate fractionation, concentration employing polysulfon membrane, purification with chromatography technique, and characterization of the enzymes. In fact, sago starch could function as a medium component in fermentation producing amylases as well as a substrate for the enzymes. The biomass of the Aspergillus contained glucose isomerase activity. Experiments with fermentor indicated that alpha amylase was best produced at agitation rate of 500 rpm, while glucoamylase was at 350 rpm, both at 1.5 vvm aeration. The SDS-PAGE of the purified enzymes found that the alpha amylase and glucoamylase had molecular weights of 53 and 36 kDalton respectively, while the glucose isomerase indicated to have two subunits with molecular weight each of 55 and 60 kDalton. As a substrate for alpha amylase and glucoamylase, sago starch exhibited higher affinity compared with arenga, corn, and cassava starches although it was still inferior to soluble starch.

PRELIMINARY STUDY ON PHOTONIC CRYSTAL-BASED EUPHOLUS CHEVROLATI BEETLE WING FOR REFRACTIVE INDEX SENSOR Hidayah, Affi Nur
Teknologi Indonesia Vol 39, No 1 (2016)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jti.v39i1.246

Micro and nanostructures from nature are very interesting for research and applicable technologies. One of theinteresting structures is beetle wing since they have unique optical properties. In this work, we have investigatedmorphology of nano and microstructure of beetle wing from Eupholus chevrolati species. We found that Eupholuschevrolati beetle wing species has perfect arrangement of nanostructure, known as photonic crystal structure. Thiskind of structure is very interesting due to its high reflectance at particular wavelength corresponding to its latticestructure. The result of SEM revealed three dimensional structure of photonic crystal structure exhibited insideEupholus chevrolati beetle wing species. Beetle wings have rigid and solid texture, so that is applicable for opticaldevices applications. Reflectance spectrum of beetle wings showed a distinctive reflectance peak, which indicatesphotonic crystal property. We observed clear reflectance peak position difference, about 20 nm wavelength, betweenbeetle wings in air and water. This difference corresponds to refractive index difference between air and water.Further development is still required to make beetle wings as refractive index sensor.

PENGARUH OSILASI TAHUNAN DAN ENSO TERHADAP VARIABILITAS OZON TOTAL INDONESIA Ambarsari, Novita; Yulihastin, Erma
Teknologi Indonesia Vol 34 (2011)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jti.v34iKhusus.44

The global ozone data of TOMS (Total Ozone Mapping Spectrometer) from NASA (National Aeronautics and Space Administration) Satellite was used from 1997 to 2005 in Indonesia (90E-151.2E, 12.5S-12.5N). The results of time series total ozone concentration data showed that the concentration varied from 242 to 275.38 Dobson Units. The highest concentration occurred from September to October, which was period of transition season from dry to rainfall season in Indonesia. In that times occurred autumn in northern hemisphere. The lowest concentration occurred from December to February, which was period of peak rainfall season in Indonesia, besides winter in northen hemisphere. The spectral analysis used FFT (Fast Fourier Transform) method founded total ozone variability in Indonesia from 1997 to 2005 was dominant infl uenced by annual oscillation (period of 11.33 months), ENSO (25.5 months), and semiannual oscillation (5.67 months).

Local Structure and Magnetic Properties of Ni-Al-C Nanocrystalline Alloys Fabricated by Mechanical Alloying Technique as a Function of Carbon Content Tarigan, Kontan; Ginting, Masno
Teknologi Indonesia Vol 35, No 2 (2012)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jti.v35i2.182

Local structural and magnetic characterization of (Ni0.5Al0.5)100-xCx (x = 0, 10, 30, and 50 at. %) nanocrystalline alloys which were prepared by mechanical alloying (MA) technique at 12 hrs milling time, have been carried out in detail. The nanocrystalline size and shape were examined using scanning electron microscopy (SEM). The effect of carbon on structural properties has been investigated using x-ray diffractometer (XRD) and extended x-ray absorption fi ne structure spectroscopy (EXAFS), whereas magnetic properties was examined by vibrating sample magnetometer (VSM). All the samples revealed nanocrystalline alloys. The maximum magnetic saturation (Ms) at about 0.7 emu/g and the minimum coercivity (Hc) at about 135 Oe would be found for 10% carbon content.

RESEARCH AND DEVELOPMENT OF NANO-STRUCTURED CAPACITOR MATERIAL BY USING ?-IRRADIATION Yunasfi, -; Mustofa, Salim
Teknologi Indonesia Vol 37, No 2 (2014)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jti.v37i2.218

Research and development on the usage of g-irradiation against nano-structured graphite which is suitable for capacitor material has been carried out. The nano-structured graphite in the form of pellet was irradiated by g-ray with variation of dose, from 100 kGy up to 600 kGy. In this research, the analysis of phase changes, the change of electrical resistivity (r), dielectric constant (er) and dielectric loss (tan d), have been carried out to the nano-structured graphite after irradiated by g-ray. The results of XRD showed that g-radiation could decline the peak intensity. The peak intensity decreased with the addition of radiation dose. Electrical resistivity values (r) also fell as an impact of g-radiation, where the decline continues with increasing radiation dose, while the value of the dielectric constant (er) has increased by g-radiation and increased steadily with the increasing of radiation dose. For the case of tan d t?? he tendency was decreased by the g-radiation and this decline continued with the increasing radiation dose. This fact suggests that there has been an interaction between g-radiation with graphite particles which can cause the impactof changes in the structure of graphite. More impact of changes in the structure of graphite is assumed that greater of energy can be stored, thus diminishes the r value and tan d, while the value of er increases.

Page 15 of 17 | Total Record : 163

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