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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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Ethnobotanical and Plant Profile Studies at Karimunjawa Village of Jepara Regency, Central Java Nurhidayati, Tutik; Saptarini, Dian; Jadid, Nurul
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.v20i1.130

Abstract

Ethnobotanical and plant profile studies that had been conducted at Karimunajawa Village of Jepara Regency were aimed to elucidate plants used by the Karimunjawa villagers and typical plants of the Karimunjawa as well as their usage. The method used for this study was questionnaire, structured and semi-structured interviews. Conditions of Karimunjawa typi-cal plants in their natural habitats were measured through bell transects that were determined based on questionnaire previously filled by the villagers. Results of the study showed that there were 39 species of wild and cultivated plants used by villagers. The plants were used for building materials (39.77%), food (23.86%), handi-craft and souvenir (23.29%), furniture (5.11%), ship construction (3.40%), medicine (2.84%), and fuel wood (1.70%). There were three species of typical plants found in the Karimunjawa Islands, i.e. Dewadaru (Fragraea elliptica), Setigi (Pemphis acidula), and Kalimasada (Cordia subcordata). Profile of the typical plants indica-ted that at the Karimunjawa Village there were sixty four individual Dewadaru and two Setigi in their narural habitats. However, no Kalimasada was found in its origi-nal habitat; the Kalimasada found in this area was that of previously planted.
New Algorithm for the Smoothing Speed Control of Induction Motor in Electric Car based on Self-Tuning Parameter PID-Fuzzy Logic Happyanto, Dedid Cahya; Soebagio, Soebagio; Purnomo, Mauridhi Hery
IPTEK The Journal for Technology and Science Vol 23, No 2 (2012)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v23i2.10

Abstract

Driving system of electric car for low speed has a performance of controller that is not easily set up on large span so it does not give a comfort to passengers. The study has been tested in the bumpy road conditions, by providing disturbances in the motor load, it is to describe the condition of the road. To improve the system performance, the speed and torque controller was applied using Field Oriented Control (FOC) method. In this method, On-Line Proportional Integral Derivative Fuzzy Logic Controller (PID-FLC) is used to give dynamic response to the change of speed and maximum torque on the electric car and this results the smooth movement on every change of car performance both in fast and slow movement when breaking action is taken. Optimization of membership functions in Fuzzy PID controller is required to obtain a new PID parameter values which is done in autotuning in any changes of the input or disturbance. PID parameter tuning in this case using the Ziegler-Nichols method based on frequency response. The mechanism is done by adjusting the PID parameters and the strengthening of the system output. The test results show that the controller Fuzzy Self-Tuning PID appropriate for Electric cars because they have a good response about 0.85% overshoot at to changes in speed and braking of electric cars.
Synthesis of Mesoporous Carbons Derived from Hypercrosslinking of Divinylbenzene – 4-Vinylbenzyl Chloride Resin Wijaya, Ulfia
IPTEK The Journal for Technology and Science Vol 18, No 4 (2007)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v18i4.165

Abstract

Conducting polymer as the precursor for developing porosity carbon by hypercrosslinked resin networks represent promising material for electrochemical electrodes. 4-Vinylbenzyl Chloride at 90% technical grade and Divinylbenzene at 80% technical grade ware prepared for synthesizing homogeneous gel-type resins via suspension polymerization. Synthesize of hypercrosslinking resin which aimed to produce high porosity carbon was then done by inducing 1,2-Dichloroetane and Iron (III) Chloride. Product of resins was found has the specific surface area 1332 m2.g-1. According to this project, it can be concluded that high surface area of resin in the presence of carbon will yield carbon with high porosity which can increase effective plate area in the development of electrochemical capacitor.
Validation of Lumped Mass Lateral Cantilever Shaft Vibration Simulation on Fixed-Pitch Vertical-Axis Ocean Current Turbine Hantoro, R. Hantoro; Utama, I. K. A. P. Utama; Sulisetyono, A. Sulisetyono; Erwandi, Erwandi
IPTEK The Journal for Technology and Science Vol 21, No 3 (2010)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v21i3.43

Abstract

Research on the emergence of force fluctuations and shaft vibration responses of ocean currents turbine generator become a serious concern to the researchers. This paper was conducted with the aim of investigation into the characteristics of lateral shaft vibration of a fixed-pitch vertical-axis ocean current turbine (VAOCT). The work was carried out numerically and experimentally using tank test. A cantilever type of shaft has been used and modeled using finite element method, and simulated using lumped mass matrix to obtain the vibration characteristics and responses. Variations of incoming fluid velocity and the corresponding rotation velocity (rpm) of VAOCT were used to identify the pattern of lateral displacement responses. Analysis of displacement responses at all nodes in x and y-direction at the same time was carried out. The presents of displacement shapes recognized have close agreement to the 1st mode shape. Potential problems on the tip of shaft obviously due to half of the force of turbine received concentrated at cantilever tip. The pattern of vibration responses from the test data shows suitable with simulation. Periodic pattern responses resulted from simulation and experiment at the validated node produce the minimum displacement error of 14% at Var-3 (U=1 m/s) and maximum of 24% at Var-2 (U=0.9 m/s).
A Direct Multiple Shooting Method for Missile Trajectory Optimization with The Terminal Bunt Manoeuvre Subchan, S. Subchan
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.v22i3.67

Abstract

Numerical solution of constrained nonlinear optimal control problem is an important field in a wide range of applications in science and engineering. The real time solution for an optimal control problem is a challenge issue especially the state constrained handling. Missile trajectory shaping with terminal bunt manoeuvre with state constaints is addressed. The problem can be stated as an optimal control problem in which an objective function is minimised satisfying a series of constraints on the trajectory which includes state and control constraints. Numerical solution based on a direct multiple shooting is proposed. As an example the method has been implemented to a design of optimal trajectory for a missile where the missile must struck the target by vertical dive. The qualitative analysis and physical interpretation of the numerical solutions are given.
Pitting Corrosion Model for Partial Prestressed Concrete (Pc) Structures in a Chloride Environment Darmawan, M. S.
IPTEK The Journal for Technology and Science Vol 20, No 3 (2009)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v20i3.109

Abstract

Prestressed concrete structures cannot escape from corrosion problems, especially when they are subjected to very aggressive environment, such as chloride environment. For prestressed concrete structures, corrosion of prestressing strands may initiate structural collapse due to higher stress levels in the steel. Research on corrosion effect on concrete structures has mainly considered the effect of corrosion have on reinforced and full prestressed concrete structures. In this study, a structural framework will be developed to predict the flexural strength of partial prestressed concrete structures in a chloride environment. The framework developed will be combined with probability analysis to take into account the variability of parameters influencing the corrosion process.
Simulation of Gas-Solid-Liquid Flow in Membrane Bioreactor Submerged Palupi, A. E.; Harahap, A. H.; Meydita, A. D.; Winardi, S.; Altway, A.
IPTEK The Journal for Technology and Science Vol 19, No 1 (2008)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v19i1.155

Abstract

Hydrodynamics characteristic for the mixing of gas-solid-liquid in membrane bioreactor submerged (MBRs) and its influence on mass transfer was studied computationally at various solid concentration, incoming gas rate, and the baffle distance. Computational method was conducted by using software GAMBIT 2.1.6. for the making of the grid which represents the calculation domain and conduct the simulation using CFD software FLUENT commercial code 6.2.16. The calculation result was recorded after the iteration reach the certain convergence level. Multiphase flow in reactor was simulated with mixture model, while to model the turbulence characteristic of the flow standard k-ε model was used. The geometric system studied is bioreactor in the form of box with flat bottom, 2 baffles, submerged hollow fiber membrane and air passage at the bottom of the reactor. For the membrane modeling, it is used two approaches that is membrane as black box and membrane as porous media. The liquid used is water, and the solid is activated sludge, and air acts as gas phase. The result indicates that gas-solidliquid system with the nearest baffle location from the membrane cause, the liquid dispersion process goes faster, so that fluid in the tank can be mixed perfectly and it can increase the gas-liquid mass transfer rate and the flux at MBRs. The increase of the solid concentration does not significantly affect the change of gas-liquid mass transfer rate and flux through the membrane, but the increase of air flow rate can increase the gas-liquid mass transfer and the flux. Porous media approach give the prediction of the gas hold up distribution more over all than black box approach. The position of baffle 9 cm from tank wall is the best position viewed from the balance between the of air flow with the circulating fluid flow. Considered from the solid distribution, double inlet MBRs is better compared to that of single inlet. Flux obtained does not show significant difference. From both approaches of the membrane model, membrane model as porous media give the simulation results closer to the experimental data.
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.
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
Vanadium Contribution to the Surface Modification of Titanium Silicalite for Conversion of Benzene to Phenol Mulyatun, Mulyatun; Prasetyoko, Didik
IPTEK The Journal for Technology and Science Vol 22, No 2 (2011)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v22i2.58

Abstract

Vanadium oxide supported on the surface of titanium silicalite was investigated in benzene hydroxylation to determine its activity as heterogeneous catalyst. Effect of vanadium loading on structure and activity of titanium silicalite was investigated. On the basis of X-ray diffraction and infrared spectroscopy techniques, it was found that the titanium structure was remained on the modified catalyst. The catalytic activity of the modified catalyst was observed to be higher than that of parent catalyst.

Page 21 of 35 | Total Record : 345

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