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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 2 (2010)" : 8 Documents clear
Implementation of Grid-computing Framework for Simulation in Multi-scale Structural Analysis Data Iranata
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.v21i2.82

Abstract

A new grid-computing framework for simulation in multi-scale structural analysis is presented. Two levels of parallel processing will be involved in this framework: multiple local distributed computing environments connected by local network to form a grid-based cluster-to-cluster distributed computing environment. To successfully perform the simulation, a large-scale structural system task is decomposed into the simulations of a simplified global model and several detailed component models using various scales. These correlated multi-scale structural system tasks are distributed among clusters and connected together in a multi-level hierarchy and then coordinated over the internet. The software framework for supporting the multi-scale structural simulation approach is also presented. The program architecture design allows the integration of several multi-scale models as clients and servers under a single platform. To check its feasibility, a prototype software system has been designed and implemented to perform the proposed concept. The simulation results show that the software framework can increase the speedup performance of the structural analysis. Based on this result, the proposed grid-computing framework is suitable to perform the simulation of the multi-scale structural analysis.
On the Development of a Vibration Energy Harvesting Mechanism and the Influence of the Number of Wire Turns Wiwiek Hendrowati; Bambang Daryanto W Daryanto W; I Nyoman Sutantra
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.v21i2.35

Abstract

This article deals with a research activity to design and to build a vibration energy harvesting (VEH) mechanism based on an electromagnetic method, where the energy source is from translational-harmonic vibration. In the developed VEH mechanism, a magnetic mass moves linearly back and forth within an electrical coil made from conductive-wire windings. In accordance to oscillating mass motion of a particular amplitude and frequency, the voltage which can be harvested is then measured and analyzed. The choice of an electromagnetic method stemmed from the availability of materials to construct the VEH mechanism. In the VEH mechanism, a mass size, a wire diameter and material, a coil length, and a vibration amplitude and frequency were considered constant, while the number of wire turns was varied. The constructed VEH was tested for 1,000, 1,500, 2,000, 2,500, and 3,000wire turns. The voltage density being harvested was recorded as 0.2820, 0.3715, 0.5695, 0.7343 and 0.9300 volt/cm3, respectively.
An Analysis Nomoto Gain and Norbin Parameter on Ship Turning Maneuver Aulia Siti Aisjah
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.v21i2.31

Abstract

First order approach of maneuvering ship model developed by Nomoto, that has commonly underpinned researchers on mathematical models of ship maneuvering, is employed by the present research in order to describe the results of Nomoto validation gain value from some type of ships. In this present study, the controls are designated using FLC, while the rules are derived from FLC; furthermore, the reference is the LQG/LTR. On the other pole, Norbin parameters are obtained under the bases of the gain and time constant output control response. Validation of Nomoto gain value is obtained through the calculation of the value of a constant gain, settling time of the first order response, and approach value toward damping ratio and natural frequency response of the system used to control the output of the second order pattern. Validation is employed on 20 types of ships with a length between 40-350 meters; as a result, it is figured out that at the Low Speed General Cargo ship, Mariner, RO/RO, and Barge Carrier have good maneuverability compared to the other 17 types of ships.
Relationship between Static Stiffness and Modal Stiffness of Structures Endah Wahyuni; Tianjian Ji Tianjian Ji
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.v21i2.36

Abstract

This paper derives the relationship between the static stiffness and modal stiffness of a structure. The static stiffness and modal stiffness are two important concepts in both structural statics and dynamics. Although both stiffnesses indicate the capacity of the structure to resist deformation, they are obtained using different methods. The former is calculated by solving the equations of equilibrium and the latter can be obtained by solving an eigenvalue problem. A mathematical relationship between the two stiffnesses was derived based on the definitions of two stiffnesses. This relationship was applicable to a linear system and the derivation of relationships does not reveal any other limitations. Verification of the relationship was given by using several examples. The relationship between the two stiffnesses demonstrated that the modal stiffness of the fundamental mode was always larger than the static stiffness of a structure if the critical point and the maximum mode value are at the same node, i.e. for simply supported beam and seven storeys building are 1.5% and 15% respectively. The relationship could be applied into real structures, where the greater the number of modes being considered, the smaller the difference between the modal stiffness and the static stiffness of a structure.
Bayes Wavelet Regression Approach to Solve Problems in Multivariable Calibration Modeling Setiawan Setiawan; Sutikno Sutikno
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.v21i2.30

Abstract

In the multiple regression modeling, a serious problems would arise if the independent variables are correlated among each other (the problem of ill conditioned) and the number of observations is much smaller than the number of independent variables (the problem of singularity). Bayes Regression (BR) is an approach that can be used to solve the problem of ill conditioned, but computing constraints will be experienced, so pre-processing methods will be necessary in the form of dimensional reduction of independent variables. The results of empirical studies and literature shows that the discrete wavelet transform (WT) gives estimation results of regression model which is better than the other preprocessing methods. This experiment will study a combination of BR with WT as pre-processing method to solve the problems ill conditioned and singularities. One application of calibration in the field of chemistry is relationship modeling between the concentration of active substance as measured by High Performance Liquid Chromatography (HPLC) with Fourier Transform Infrared (FTIR) absorbance spectrum. Spectrum pattern is expected to predict the value of the concentration of active substance. The exploration of Continuum Regression Wavelet Transform (CR-WT), and Partial Least Squares Regression Wavelet Transform (PLS-WT), and Bayes Regression Wavelet Transform (BR-WT) shows that the BR-WT has a good performance. BR-WT is superior than PLS-WT method, and relatively is as good as CR-WT method.
Multi-person Decision Model for Unfinished Construction Project Utomo, Christiono
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.v21i2.33

Abstract

This paper discusses a proposed model of multi-person decision on prioritizing selection with regard to continuing or terminating unfinished construction projects. This involved multiple steps including determining criteria and sub criteria, selecting and weighting of alternatives, optimizing, and analyzing coalition formation and agreement option. Criteria and sub criteria that were obtained from perspectives of 120 project managers are the first basis to construct decision hierarchy. The model is implemented in one of the biggest private construction projects in Indonesia. The implementation was based on the Analytic Hierarchy Process for multi criteria decision involving coalition and agreement options in a multi-person decision. Goal Programming was used to optimize based on cost constrains. The results demonstrate a process of multiperson decision to select priorities of each alternative to each decision and concluded that some of the projects were continued, postponed or terminated. The new direction of research presented in this paper presents some interesting challenges to those involved in modeling computer-based multi-person decision support utilizing both Multi Agent System and Multi Criteria Decision Making.
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.
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

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