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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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Sintering Effect on the Microstructure And Magnetic Properties of Co-Alxoy Composite Compound Sri Mulyaningsih; Setyo Purwanto; Mujamilah Mujamilah; Wisnu A. Adi; Azwar Manaf
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.v19i2.154

Abstract

Research on sintering effect on the micro structure and the magnetic properties of composite Co-AlxOy materials has been done. The experiment was carried out by high energy milling (HEM) to refine Co and Al sample powder, followed by sintering process. The composition of sample was Co73Al27 wt% with weight ratio to the ball was 1:2.7. The milling time was varied within 4.5, 12 and 20 hours, while sintering process was conducted at 384ºC and 484ºC. Several new peaks were found after sintering process and identified as a Co-Al2O4 compound. The experiment data shows the saturation magnetization Ms value was decline for the entire sample by the sintering process. The Mr value for the 12h milling was remind stable about 9 emu/gr but, for 4.5 milling was decline from 17.5 to 9.2 and 6.2 emu/gr , while for 20h milling from 13,5 to 9.25 and 8 emu/gr. No visible changes in the microstructure are observed.
Biodiesel Production from Rubber Seed Oil by Supercritical Methanol Method Abdul Shokib; Pramita Gumanti; M. Rachimoellah Rachimoellah
IPTEK The Journal for Technology and Science Vol 21, No 2 (2010)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v21i2.32

Abstract

The purpose of this research is to investigate the effect of reaction temperature, reaction time and molar ratio between methanol and oil on the yield of biodiesel product. Rubber seeds with 45.63 wt% oil content and contained 17 wt% Free Fatty Acid was used as the main feedstock. Supercritical treatment with the methanol temperature of around 350oC and pressure of about 43MPa was used as the reaction method. It was found that yield of biodiesel product increased with the increase of reaction temperature until the temperature of about 350oC, reaction time, until the time of 9 min and molar ratio of methanol to oil until the ratio of 42:1. The highest yield of biodiesel produced was achieved under the reaction temperature of 350oC, reaction time of 9 minutes and 42:1 methanol to oil ratio.
Synthesis and Toxicity Test Of Zinc (II) Pyridine-2,6-Dicarboxylate Complexes Fahimah Martak; Tia Ayu Christanti
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.v25i1.471

Abstract

Complexes of zinc (II) with pyridine-2,6-dicarboxylic acid were synthesized from a reaction between zinc(II) chloride and pyridine-2,6-dicarboxylic acid with two different methods. The first method was carried out by reflux method, mixing a certain mole ratio of metal and ligand in the mixed solution of methanol:water (1:1) as the solvent. The second method was carried out by employing a direct reaction of metal and ligand in a 1:2 mole ratio of the same solvent as it is of the first method. The first method yielded a small clear crystal grains shaped like parallelogram with the molecular formula of [Zn(H2dipic,dipic)Zn2(10H2O)]Cl4∙5H2O (Complex I-trinuclear). The second method yielded the colorless needle-like crystals and molecular formula [Zn(H2dipic)2Zn(H2O)5]Cl4∙2H2O (Complex II-dinuclear). Both complex compounds were tested their toxicity using Brine Shrimp Lethality Test (BSLT) method and obtained LC50 values of 989.26 and 503.32 ppm, respectively.
Cyst and Tumor Lesion Segmentation on Dental Panoramic Images using Active Contour Models Ingrid Nurtanio; I Ketut Eddy Purnama; Mochamad Hariadi; Mauridhi Hery Purnomo
IPTEK The Journal for Technology and Science Vol 22, No 3 (2011)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v22i3.66

Abstract

Active contours, or snakes, are computer-generated curves that move within images to find object boundaries. They are often used in computer vision and image analysis to detect and locate objects, and to describe their shape. Thus active contour can be used for object segmentation, especially the lesion in medical images. This paper presents the application of active contour models (Snakes) for the segmentation of lesions in dental panoramic image. The aim is to assist the clinical expert in locating potentially cyst or tumor cases for further analysis (e.g. classification of cyst or tumor lesion). In order to apply the snake formulation, color images were converted into gray images. Then, with correct parameters, we can create a snake that is attracted to edges or termination. Initializing contour, choosing parameter value and number of iteration affect the behaviour of the snake in a particular way. Using Receiver Pperating Characteristic (ROC), an average accuracy rate of 99.67 % is obtained. Examples of Snake segmentation results of lesions are presented.
Study of Air Velocity and Temperature Gradient in Lecture Room Through Mixed and Displacement Ventilation Systems to Improve the Thermal Comfort Bambang Iskandriawan
IPTEK The Journal for Technology and Science Vol 21, No 2 (2010)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v21i2.93

Abstract

Air ventilation system is considered crucial in the target of maintaining clean and fresh room air at all times. It will improve the thermal comfort and indoor air quality along with the activities of occupant. This investigation explores the influence of fresh air diffuser location to the thermal comfort factor especially in the lecture room. It will contrast two types of ventilation: the mixed and the displacement ventilation. The thermal comfort factor is represented by means of air velocity and temperature. Using Fluent 6.2 as CFD (Computational Fluid Dynamics) simulation program, all the variables will be exploited. The specific boundary type’s room model is verified in GAMBIT software generating such a specific lecture room. The finding shows that the displacement ventilation system has benefit in the propensity of controlling the heat and air velocity compare to the mixed ventilation
Estimation of Surabaya River Water Quality Using Kalman Filter Algorithm Ali Masduqi; Erna Apriliani
IPTEK The Journal for Technology and Science Vol 19, No 3 (2008)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v19i3.145

Abstract

According to previous studies on Surabaya River water, quality of this river water was very bad or on polluted condition. This conclusion was based on monitoring data of water quality at several monitoring points. Because of river water quality is a fluctuative condition, many monitoring data are needed. While, monitoring of Surabaya River water quality was done routinely at nine monitoring points. Amount of the monitoring point is not enough when data will be used for determining water quality condition. For this reason, it is need to develop a method to estimate overall river water quality based on a little amount of data. One of estimation method is Kalman filter, an algorithm that combines a model and a measurement. The experiment of Kalman filter algorithm was conducted. The results were accurate and closely with a measurement. Based on the results, application of Kalman filter algorithm will help to predict water quality for the future and to estimate overall water quality along of river, although amount of measurement data is a little.
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.
Feature Selection with Support Vector Machines Applied on Tornado Detection Budi Santosa
IPTEK The Journal for Technology and Science Vol 18, No 1 (2007)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v18i1.178

Abstract

In this paper, a linear programming support vector machine which is based on L1-norm is applied to do feature selection in the tornado data set. The data is the ouputs of Weather Surveillance Radar 1998 Doppler (WSR-88D). The approach is evaluated based on the indices of probability of detection, false alarm rate, bias and Heidke skill. Tornado circulation attributes/variables derived largely from the National Severe Storms Laboratory Mesocyclone Detection Algorithm (MDA) have been investigated for their efficacy in distinguishing between mesocyclones that become tornadic from those which do not.
Generating Hourly Rainfall Model using Bayesian Time Series Model (A Case Study at Sentral Station, Bondowoso) Entin Hidayah; Nur Iriawan; Nadjadji Anwar; Edijatno Edijatno
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.v22i1.57

Abstract

Disaggregation of hourly rainfall data is very important to fulfil the input of continual rainfall-runoff model, when the availability of automatic rainfall records are limited. Continual rainfall-runoff modeling requires rainfall data in form of series of hourly. Such specification can be obtained by temporal disaggregation in single site. The paper attempts to generate single-site rainfall model based upon time series (AR1) model by adjusting and establishing dummy procedure. Estimated with Bayesian Markov Chain Monte Carlo (MCMC) the objective variable is hourly rainfall depth. Performance of model has been evaluated by comparison of history data and model prediction. The result shows that the model has a good performance for dry interval periods. The performance of the model good represented by smaller number of MAE by 0.21 respectively.
Development of New Rendemen Formula as an Effort to Control the Performance of Sugar Factory Bambang A. Santoso; Toto Martoyo; Subhanuel Bahri
IPTEK The Journal for Technology and Science Vol 20, No 1 (2009)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v20i1.134

Abstract

Based on the data of sugar factory performance in Java during 1936-1940 and 1956-2000 milling season periods, there are three important factors that can control contribution of each sector at sugar fac-tory and absolutely affect targeted rendemen. Those fac-tors include cane pol in the field, harvesting efficiency and factory efficiency. Cane pol in the field is a result of plantation sector performance. Harvesting efficiency re-presents the performance of harvesting sector, while fac-tory efficiency has relationship with the performance of factory itself. In this research, the standard of factory performance was the data of factory performance in the milling season from 1936 to 1940 and the factory perfor-mance tested was the data of factory performance in the 1956-2000 milling season period. The aim of this research was to obtain a formula of rendemen calculation that represents a performance of all production aspects at sugar factory. The formula used for rendemen calculati-on was Rendemen (%) = cane pol in the field (%) x har-vesting efficiency (%) x factory efficiency (%) x 10-4. By using this concept, it is expected that targeted rendemen can be achieved since this concept can control all stages of production using the standard of each production aspect.

Page 26 of 35 | Total Record : 345

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