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IPTEK The Journal for Technology and Science
ISSN : 08534098     EISSN : 20882033     DOI : -
Core Subject : Science,
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.
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Articles 5 Documents
Search results for , issue "Vol 25, No 2 (2014)" : 5 Documents clear
Multi-Responses Optimization Of Edm Sinking Process Of Aisi D2 Tool Steel Using Taguchi Grey–Fuzzy Method Bobby Oedy Pramoedyo Soepangkat; Arif Wahyudi; Bambang Pramujati
IPTEK The Journal for Technology and Science Vol 25, No 2 (2014)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v25i2.528

Abstract

Rough machining with Electro Discharge Machining (EDM) process gives a large Material Removal Rate (MRR) and high Surface Roughness (SR), while finish machining gives low SR and very slow MRR. In this study, Taguchi method coupled with Grey Relational Analysis (GRA) and fuzzy logic has been applied for optimization of multiple performance characteristics. The EDM machining parameters (gap voltage, pulse current, on time and duty factor) are optimized with considerations of multiple performance characteristics, i.e., MRR and SR. The quality characteristic of MRR is larger-is-better, while the quality characteristic of SR is smaller-is-better. Based on Taguchi method, an L18 mixed-orthogonal array is selected for the experiments. By using the combination of GRA and fuzzy logic, the optimization of complicated multiple performance characteristics was transformed into the optimization of a single response performance index. The most significant machining parameters which affect the multiple performance characteristics were gapvoltage and pulse current. Experimental results have also shown that machining performance characteristics of EDM process can be improved effectively through the combination of Taguchi method, GRA and fuzzy logic.
Rural Urban Disparity in and around Surabaya Region, Indonesia Vely Kukinul Siswanto; Jayant K. Routray; Rima Dewi
IPTEK The Journal for Technology and Science Vol 25, No 2 (2014)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v25i2.468

Abstract

A shift in development towards the outskirts of urban areas changes the characteristics of the region and can ultimately lead to urban disparities in economic and social terms. The current study has tried to divide the study area covers the areas of surrounding Surabaya as urban, peri urban and rural areas with reference to three time periods (2008, 2009 and 2010) and shows that the typology in the study area changes each year. Furthermore, based on the theil index analysis, using a number of pre-prosperous household for social disparity and per capita GDP (Gross Domestic Product) for economic disparity shows that urban and peri urban areas have medium and high level of social and economic disparity compare with rural area which have low levels of disparity. Through multivariate correlation analysis can be seen that the health center distance, electricity and water users effecting the social disparity. Moreover, the financial, industrial, electricity, trade, construction, transportation, agriculture, and mining sector's productivity have a significant relationship with the economic disparity. Health facilities, water and electricity improvement strategies to be followed for reducing the social disparity. Electricity improvement, water, services sector, transportation infrastructure, and industrial development to reduce the economic disparity.
Fiber Optic Adaptive Probe as a Cuvette Substitution for UV-Vis Spectrophotometer (Genesis 10S) Kurniawan, Fredy; Suharmanto, Edi
IPTEK The Journal for Technology and Science Vol 25, No 2 (2014)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v25i2.536

Abstract

Fiber optic adaptive probe UV-Vis for Genesis 10S has been fabricated to substitute cuvette for real time analysis. Most of standard spectrophotometers UV-Vis (the common type) use cuvette to place sample which is being analyzed. The light pass through the sample in the cuvette to detector then the intensity of the absorption of the solution is measured. Most of the cuvette system requires to transferring sample solution to cuvette from its original vessel, so the real time analysis cannot be conducted. The probe with special design using fiber optic cable FT-Au tonics 420-10 has been made to substitute the cuvette system. The light from the source moved inside fiber optic cable, which has been cut in the middle of the cable (the sample can passes through at this gap), to the detector. The end (entrance and exit) of the fiber optic was designed so that it fit to the compartment of the Genesis 10S spectrophotometer without any modification from the standard instrument condition. The spectrum results from the probe in varies gap, in the range 0.2 – 1 cm, was observed. The gap in the middle of the fiber optic was equal to the length of the pathway in the cuvette system. Rhoda mine B was used as the sample with variation concentration 4.175 × 10-5 M, 3.34 × 10-5 M, 2.5 × 10-5 M, and 1.67 × 10-5 M. The spectrum result of adaptive fiber optic probe was compared to the spectrum of standard cuvette system. The optimum result was provided using 0.2 cm gap. The maximum wavelength absorbance of adaptive fiber optic probe was at 533 nm which similar to the cuvette system
Preliminary Study of Spatial Verification for Wind Model Output Against Oceansat-2 Satellite Mujiasih, Subekti; Prasetyo, Eko
IPTEK The Journal for Technology and Science Vol 25, No 2 (2014)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v25i2.464

Abstract

Information on wind, which is one of selected marine weather forecasts, is very important to support sea transportation safety. To increase the forecast quality, the parameter should be verified. This study will provide spatial verification wind from wind waves model output against wind from oceansat-2 Satellite data and AWS on board (Automatic Weather Station). Wind of model output includes hindcast and forecast 18 hours ahead. The chosen sample data were some extreme conditions in Java Sea during November 2012 until October 2013. Despite the same trend of wind direction displayed by both model output and Oceansat-2, the study result found significant gap of wind speed. This information will be recommendation for marine weather forecaster
Effect of Hydrothermal Extraction Condition on The Content of Phenolic Compound Extracted from Rind of Mangosteen (Garcinia mangostana) and Its Antioxidant Efficiency Ash Shiddiqi, Qifni Yasa; Karisma, Achmad Dwitama; Machmudah, Siti; Widiyastuti, Widiyastuti; Nurtono, Tantular; Winardi, Sugeng; Wahyudiono, Wahyudiono; Goto, Motonobu
IPTEK The Journal for Technology and Science Vol 25, No 2 (2014)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v25i2.462

Abstract

Xanthone is an antioxidant compound contained in the rind of mangosteen. There are some methods to extract Xanthone from rind of mangosteen, and one of them is hydrothermal extraction. Hydrothermal extraction is a method to obtain xanthone from rind of mangosteen using water at teIn this work, the effect of extraction temperature, pressure, and mode (batch and continuous), and particle size of starting material on the yield and recovery of extracted xanthone and phenolic compounds was investigated. Extraction was carried out at various temperatures (120, 150, and 180oC) and pressures (1, 3, and 5 MPa) and constant flow rate of 1 mL/min. The xanthone content and antioxidant efficiency of extract was examined by using spectrophotometer, while the concentration of total phenolic compounds in the extract was determined with folin ciocalteu reagent and examined using spectrophotometer In order to confirm the extracted phenolic compounds, the extract residue was analyzed by using FTIR. The experimental result showed that the increase in pressure and temperature caused an increase in total phenolic compound concentration and yield of xanthone. In addition, the result also showed that antioxidant activities were observed in the extract of mangosteen rind.

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