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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 8 Documents
Search results for , issue "Vol 21, No 1 (2010)" : 8 Documents clear
Ethanol Production from Molasses with Immobilized Cells Technique in Packed Bed Bioreactor by Extractive Musfil AS; Tri Widjaja; Ali Altway; R. Darmawan Darmawan
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.v21i1.26

Abstract

The aim of this research was to study the effect of total sugar concentration, Ca-Alginate and K Carrageenan density in immobilized cells on packed-bed and batch bioreactor performance for ethanol production. In addition, this research was also aimed to study the effect of solvent flow rate on packed column performance expressed as % extraction recovery. This experiment was carried out with total sugar concentration of 10, 14, 18 % (v/v) and immobilized cells Ca-Alginate and K-Carrageenan at a density of 2% (w/v) with amyl alcohol as solvent. Based on the result of this study, it is concluded that the total sugar concentration influenced the concentration, yield and productivity of ethanol. The result of this study for immobilized Ca-Alginate cells showed that the maximum ethanol product concentration, yield and productivity were 7.28% g/l, 57.48 g/l, 38.22%, 71.85 g/l.hr, respectively. Meanwhile, immobilized K-Carrageenan cells showed the maximum ethanol product concentration, yield and productivity as 7.22% /56.99 g/l, 26.73%, and 68.40 g/l.hr, respectively. In extraction process, increasing amyl alcohol solvent flow rate will increase mass transfer and hence increase ethanol recovery.
Concrete Failure Modeling Based on Micromechanical Approach Subjected to Static Loading Endah Wahyuni
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.v21i1.22

Abstract

In this paper, a micromechanical model based on the Mori-Tanaka method and the spring-layer model is developed to study the stress-strain behavior of concrete. The concrete is modeled as a two-phase composite. And the failure of concrete is categorized as mortar failure and interface failure. The research presents a method for estimating the modulus of concrete under its whole loading process. The proposed micromechanical model owns the good capabilities for predicting the entire response of concrete under uniaxial compression. It is suitable that tensile strain is as the criterion of concrete failure and the prediction of crack direction also fits with experimental phenomenon.
Flood Forecasting using a Transfer Hydrograph Approach Saihul Anwar
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.v21i1.27

Abstract

This paper describes the development and application of a transfer hydrograph approach to flood forecasting on the Cimanuk River at the city of Jatigede in West Java, Indonesia. The Transfer Hydrograph (TH) is a transfer function that transforms total rainfall into a flood hydrograph at the basin outlet. As opposed to the conventional unit hydrograph approach which uses effective rainfall and direct runoff, the transfer hydrograph uses the total rainfall and the direct runoff at the basin outlet. The Cimanuk river basin (drainage area : 1,442 km2) has four sub basins. It was found to be necessary to further extend the application of the transfer hydrograph concept to include all channel routing effects. This because the rainfall at each subbasin was found to be quite independent of the rainfall at other sub basins, and run off data were only available at the basin outlet at Jatigede. Using the available data, transfer hydrograph were derived for each sub basin and later combined to give the runoff hydrograph at Jatigede. The approach was tested against recorded rainfall-run off data at Jatigede and was found to give very reasonable results. For flows above 300 m3/second, the maximum error of prediction was less than 12 %.
Evaluating Error of Temporal Disaggregation from Daily into Hourly Rainfall using Heytos Model at Sampean Catchments Area Hidayah, Entin; Anwar, Nadjadji; Edijatno, Edijatno; Iriawan, Nur
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.v21i1.25

Abstract

Developing a rainfall-runoff model sufficient to flood prediction hourly rainfall data. Lack of automatic rain gauge for high resolution rainfall in catchment area can be an obstacle for the modeling. Otherwise, the manual rain gauges may spread on all of catchments areas, providing daily rainfall. Daily rainfall disaggregation to hourly rainfall is an innovation to get higher temporal resolution of the rainfall. This paper attempts to evaluate the implementation of rainfall disaggregation model in Sampean Catchments Area using Heytos. The proposed parameter optimation use Moment Performance model that tested by calibrating it with available hourly data. The results of model indicated that only data within five months had good performance. The estimation result showed that relative error total of January, February, August, November, and December was less than one. In case of March, April, May, June, July, September, and October the model could not result respectively to generate model.
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.
Performance of Submerged Membrane Bioreactor Combined with Powdered Activated Carbon Addition for the Treatment of an Industrial Wastewater Widjaja, Tri; Altway, Ali; Soeprijanto, Soeprijanto
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.v21i1.24

Abstract

Membrane technology is one of the alternative solutions to overcome industrial wastewater treatment developed nowadays. The addition of PAC (Powdered Activated Carbon) in the activated sludge using Submerged Membrane Adsorption Hybrid Bioreactor (SMAHBR) is expected to increase the organic material removal. The purpose of this study was to determine the performance of submerged membrane bioreactor and activated carbon adsorption capacity of organic materials in wastewater. This study used SIER (Surabaya Industrial Estate Rungkut – Surabaya, Indonesia) waste as activated sludge operated at Mixed Liquor Suspended Solid (MLSS) concentrations of 8000 and 15000 mg/l, and Chemical Oxygen Demand (COD) concentrations of 1500, 2500 mg/l, Sludge Retention Time (SRT) of 10;20; and 30 days and activated carbon variables of 0%; 2.5%; 5%; 7.5%; 10%. The results showed that the fouling potential occurred at high MLSS where the COD removal occurred at PAC addition of 10% reaching 91.86%. High Soluble Microbial Product (SMP) accumulation (± 10 mg/l) occurred in short SRT and high MLSS concentration. PAC addition resulted in decreased microorganisms in the reactor and better effluent of SMAHBR, as a result, the performance of the submerged membrane bioreactor would be restored.
Text Mining for Fuzzy-based Emotion Expressions Sumpeno, Surya; Hariadi, Mochamad; Hery, Mauridhi
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.v21i1.29

Abstract

A model of emotion representation in the form of facial expressions using text mining technique, followed by fuzzy-based mechanisms using Fuzzy Inference System (FIS) is proposed. The model classifies the emotional content of sentences from text input and expresses corresponding emotions by a facial expression. Text input is classified using Na¨ıve Bayes text classifier, while facial expression of a virtual character are controlled by Mamdani fuzzy inference system utilizing results from text classifier. This model is able to show the facial expression with admixture blending emotions. As a demonstration, examples of facial expressions with corresponding text inputs as results from the implementation of our model are shown.
Dividing Streamline Formation Channel Confluences by Physical Modeling Minarni Nur Trilita; Nadjadji Anwar; Djoko Legono; Basuki Widodo
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.v21i1.23

Abstract

Confluence channels are often found in open channel network system and is the most important element. The incoming flow from the branch channel to the main cause various forms and cause vortex flow. Phenomenon can cause erosion of the side wall of the channel, the bed channel scour and sedimentation in the downstream confluence channel. To control these problems needed research into the current width of the branch channel. The incoming flow from the branch channel to the main channel flow bounded by a line distributors (dividing streamline). In this paper, the wide dividing streamline observed in the laboratory using a physical model of two open channels, a square that formed an angle of 30º. Observations were made with a variety of flow coming from each channel. The results obtained in the laboratory observation that the width of dividing streamline flow is influenced by the discharge ratio between the channel branch with the main channel. While the results of a comparison with previous studies showing that the observation in the laboratory is smaller than the results of previous research.

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