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IPTEK The Journal for Technology and Science
Published by Institut Teknologi Sepuluh Nopember Surabaya
ISSN : 08534098     EISSN : 20882033     DOI : -
Core Subject : Science,
Computer Science & IT
IPTEK The Journal for Technology and Science (eISSN: 2088-2033; Print ISSN:0853-4098), is an academic journal on the issued related to natural science and technology. The journal initially published four issues every year, i.e. February, May, August, and November. From 2014, IPTEK the Journal for Technology and Science publish three times a year, they are in April, August and December in online version.
Arjuna Subject : -
Articles 345 Documents
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Structural Characterization of Tungsten Oxides Supported on Titanium Silicalite Prasetyoko, Didik; Ramli, Zainab; Endud, Salasiah; Nur, Hadi
IPTEK The Journal for Technology and Science Vol 19, No 2 (2008)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v19i2.150

Abstract

Titanium silicalite (TS-1) is known as an active material catalyst in the epoxidation reaction. In this study, tungsten oxides (WO3) with various loading amount have been supported on the TS-1 to increase of the catalytic activity of the TS-1 material. The solids structure and property were investigated by X-ray diffraction (XRD), temperature programmed reduction (TPR), ultra violet-visible diffuse reflectance (UV-Vis-DR) and infrared (IR) spectroscopy and scanning electron microscopy (SEM) techniques. The results showed that the structure of TS-1 is not collapsed after impregnation of WO3. It was also found that tungsten species have interacted with the silanol groups on the surface of TS-1.
Performance Fuzzy Logic Control to Minimize Output Voltage Ripple and Balanced Current Distribution of DC-DC Converters in Parallel Non-Identical Bambang Suprianto; Mochamad Ashari; Mauridhi Hery Purnomo
IPTEK The Journal for Technology and Science Vol 21, No 1 (2010)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v21i1.28

Abstract

Analysis of DC-DC converters are arranged in parallel with the inductor parameters which are different from what discussed in this paper. Buck DC-DC converter using non-identical model, that is different in the value of inductance which is L1 ≠ L2 ≠ L3. Research techniques are taken from the difference of current flows of each converter i.e. I1-I2 and I1- I3 and the reference current is I1. This current difference results are used as input controller. PID and Fuzzy Inference System with 5 gbell membership function are used as a controller. The results of this study indicate a significant system performance. Output voltage ripple is 10 mV with the total output current is 63.7 Ampere. Each DC-DC converter provides a current of contribution to the load 21.28 Ampere. The difference of the current distribution of each converter module range is 1mA - 4mA RMS (Root Mean Square) using PID control, while using Fuzzy Logic Control for differences in the distribution of current is 0.1 mA RMS and the output voltage is 48 volt. Fuzzy Logic Control performance has shown an improvement of control systems to reduce the output voltage ripple and the ability to share load current equally into each DC-DC converter.
Effects of Photoperiodism to The Growth Rate of Hibiscus sabdariffa L Muslihatin, Wirdhatul; Daesusi, Ruspeni
IPTEK The Journal for Technology and Science Vol 25, No 1 (2014)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v25i1.479

Abstract

Red roselle (Hibiscus saddariffa L.) is a short day plant, this plant is only cultivated in a certain time period. There is a need to manipulate the environment where this plant can grow. The objective of this research was to study the influence of day length tothe relative growth rate (RGR) of H.sabdariffaL. Day length treatment was carried out by covering plants by black cover. Day length treatments were given in 8, 9,10, 11 and 12 hours of light exposure. Parameters measured were RGR of height plant, diameter of stem, number, and color of leaves. Harvesting was carried out when the flower crown fell or petals furl (the age of plants reached 3-4 months). The result of this research showed that highest plant was obtained at 10 hours day length (128.20 cm), the largest stem diameter growth rate was obtained at 8 hours (1.79 cm), number of leaves at 10 hours (183.40),and green color of leaves on 12 hours (scale 4). The highest RGR was obtained at 8 hours for all parameters except the height of plant and the color of leaves. Plant height, diameter and number of leaves at 8,9,10, and 11 hours of day length did not show significance difference. This showed that roselle is a short day length plant that grow optimal under 12 hours of day length.
Non-Catalytic and MgSO4 - Catalyst based Degradation of Glycerol in Subcritical and Supercritical Water Media Yuniati, Yuyun; Sumarno, Sumarno; Mahfud, Mahfud
IPTEK The Journal for Technology and Science Vol 22, No 1 (2011)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v22i1.53

Abstract

This research aims to study the glycerol degradation reaction in subcritical and supercritical water media. The degradation of glycerol into other products was performed both with sulphate salt catalysts and without catalyst. The reactant was made from glycerol and water with the mass ratio of 1:10. The experiments were carried out using a batch reactor at a constant pressure of 250 kgf/cm2, with the temperature range of 200-400oC, reaction time of 30 minutes, and catalyst mol ratio in glycerol of 1:10 and 1:8. The products of the non-catalytic glycerol degradation were acetaldehyde, methanol, and ethanol. The use of sulphate salt as catalyst has high selectivity to acetaldehyde and still allows the formation alcohol product in small quantities. The mechanism of ionic reaction and free radical reaction can occur at lower temperature in hydrothermal area or subcritical water. Conversion of glycerol on catalytic reaction showed a higher yield when compared with the reaction performed without catalyst
Phase Transformation on Interface between NiCoCrAlY Bond Coat and Substrate and Study of Thermal Barrier Coating as High Temperature Material Purwaningsih, H; Noerochim, L.; Fajarain, R.; Hakim, J.A.; Sulistijono, Sulistijono
IPTEK The Journal for Technology and Science Vol 21, No 4 (2010)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v21i4.89

Abstract

Thermal Barrier Coating material consists of Yttria stabilized zirconia (YSZ) as a top coat and bond coat NiCoCrAlY. It is used to protect NiCoCrAlY super alloys for high temperature applications due to its corrosion resistant properties and resistance to thermal fatigue. In the present study, top coat and bond coat were deposited on the substrate using plasma spraying process, followed by thermal fatigue treatment, by heating up to 900 oC for 5 hours and cooling down to 25 oC for 15 minutes, this process called one cycle. Thermal fatigue was conducted until the material failure. Electron microscope was used to analysis microstructure of the sample after thermal fatigue and x-ray diffraction to analysis phase changed on the interface between bond coat and substrate. The result showed that the specimens failed at 42 cycles (210 hours). A new phase identified as Ni3Al was formed.
Nearshore Bathymetry Estimation Using Video Coastal Monitoring System Zikra, Muhammad
IPTEK The Journal for Technology and Science Vol 19, No 4 (2008)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v19i4.141

Abstract

The invention of new digital technology of images from video camera systems now can provide information of the shoreward propagation of wave using pixel intensity time series that collected at cross-shore array. From this video image of intensity data, we can measure the wave speed (or, equivalent to wave number). Then the local water depth is inferred from linear wave theory dispersion relation equation. This paper describes the cross-spectral correlation approach scheme for investigating wave speed or equivalent wave number from video image data sets. The approach based on a pixel array analysis that utilizes a nonlinear inverse method. The solution is tolerant to noise and other forms of sampling deficiency. The solution includes error predictions that can be used to evaluate sample designs (data gaps) and the signal coherence. The technique was tested using 30 days of hourly data collected at Egmond beach, Netherlands. The result showed that the method have capability to derive wave number prediction from pixel intensity time series to support bathymetry estimation in near shore area through inversion of an appropriate wave dispersion model.
Hydrogen Sorption Behavior of the MgH2-Ni Prepared by Reactive Mechanical Alloying Mustanir, Mustanir; Jalil, Zulkarnain
IPTEK The Journal for Technology and Science Vol 20, No 4 (2009)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v20i4.19

Abstract

Regarding the use of hydrogen in fuel cell for mobile or stationary applications, metal hydrides can offer a high hydrogen volume capacity and a safe alternative compared with liquid storage or with compressed gas. Among the metal hydrides, magnesium is considered as one of potential hydrogen storage materials because of its high capacity (7.6 wt%), lightweight and low cost. However, high work temperature would slow down kinetics reaction and harden activation process limit practical application of Mg-based hydrides as well. Recently, the high energy ball milling was successfully introduced to prepare hydrogen storage materials. In this work, MgH2 catalyzed with Ni nanoparticles was synthesized by planetary type ball milling under high pressure of hydrogen at 100 bar (10 MPa). As a result, small amount of Ni in nanometer scale acts as a suitable catalyst for kinetics improvement of MgH2 which could absorb 5.3 wt% of hydrogen within 5 minutes at 300ºC. It is obvious that small amount Ni (2 mol%) has much better catalyst than catalyst in nanoparticle size; and at the same time, it is allowed to reduce the milling process for short time (2 hours).
Theoretical Exposition of A Single Electron Quantum Dot T. Cahyanto, Wahyu; Abraha, Kamsul; Nurwantoro, Pekik
IPTEK The Journal for Technology and Science Vol 18, No 2 (2007)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v18i2.174

Abstract

This paper will review atomic-like phenomena in a semiconductor quantum dot which their size, shape and interactions can be precisely controlled through the use of nanofabrication technology. It has been shown that by confining electrons in three dimensions inside semiconductors, quantum dots can show many of the phenomena observed in atoms and nuclei and so called artificial atom. Because of its controlable system, it is possible to explore the correlation effects in regimes that cannot otherwise be accessed in other physical systems. For simplicity, this work will focus on a circular-shape single electron quantum dot trapped by polar two-dimensional harmonic potential in the presence of an external magnetic field. Both Zeeman splitting and spin orbit interaction are neglected in our calculation. The calculation show that Fock-Darwin spectrum will enter Landau regime, where when cyclotron frequency is much larger than potential confinement .
Performance Characteristics Optimization of Electrical Discharge Machining Process Using Back Propagation Neural Network And Genetic Algorithm Napitupulu, Robert; Wahyudi, Arif; Soepangkat, Bobby Oedy Pramoedyo
IPTEK The Journal for Technology and Science Vol 25, No 3 (2014)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v25i3.527

Abstract

This study attempts to model and optimize the complicated electrical discharge machining (EDM) process using soft computing techniques. Artificial neural network (ANN) with back propagation algorithm is used to model the process. In this study, the machining parameters, namely pulse current, on time, off time and gap voltage are optimized with considerations of multiple performance characteristics such as metal removal rate (MRR) and surface roughness. As the output parameters are conflicting in nature so there is no single combination of cutting parameters, which provides the best machining performance. Genetic algorithm (GA) with properly defined objective functions was then adapted to the neural network to determine the optimal multiple performance characteristics.
Dynamic Modeling and Damping Function of GUPFC in Multi-Machine Power System Hadi, Sasongko Pramono
IPTEK The Journal for Technology and Science Vol 22, No 4 (2011)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v22i4.76

Abstract

This paper presents a new dynamic model of multi-machine power system equipped with GUPFC for power system study, and using PSS and GUPFC POD controller some effective control schemes are proposed to improve power system stability. Based on UPFC configuration, an additional series boosting transformer is considered to define a GUPFC configuration and its mathematical model; Phillips-Heffron scheme is used to formulate machine model, and modification of network dealing with GUPFC parameter is carried out to develop a MIMO as well as comprehensive power system with GUPFC model. Genetics Algorithm method was proposed to lead-lag compensation design, this technique provides the parameter controller. The controller produced supplementary signals, the PSS for machine and POD for GUPFC. By applying a small disturbance, the dynamic stability power system was investigated. Simulation results show that the proposed power system with GUPFC model is valid and suitable for stability analysis. The installation of GUPFC without POD decreased the damping oscillation. But, the results show that the presence of GUPFC in power system network provided by PSS and POD controller is very potential to improve system stability. A 66% overshoot reduction could be reached, it is obtained 12 s in settling time (shorter), although the rise time become 700 ms longer. Simulation results revealed that the role of POD controller is more dominant than the PSS, however both PSS and GUPFC POD controller simultaneously present a positive interaction. Phase angle of converter C, δC is the most significant control signal POD in oscillation damping.

Page 20 of 35 | Total Record : 345

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