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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 18, No 3 (2007)" : 5 Documents clear
Application of Adaptive QAM Modulation and Diversity Scheme for 30 GHz Cellular Communications under the Impact of Rain Attention in Indonesia Gamantyo Hendrantoro; Achmad Mauludiyanto; Ninik D. Yundariani
IPTEK The Journal for Technology and Science Vol 18, No 3 (2007)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v18i3.167

Abstract

In millimeter-wave wireless cellular systems like Local Multipoint Distribution Services (LMDS) rain attenuation is an essential factor of performance degradation. It can cause signal outages and poor quality of signal reception. To mitigate the problem, a combination of diversity and adaptive modulation is proposed. To investigate the impact of the use of these techniques, a simulation is performed for a 30 GHz cellular system to obtain SNR (signalto- noise ratio), diversity gain, modulation level and BER (bit error rate). Analysis of the implementation of the combined techniques is accomplished by taking into account such factors as length of links and the combining method Simulation results show that diversity can improve the overall system SNR. Diversity gain of up to 15 dB can be achieved on two 4-km converging links at 0.01% outage probability when maximal-ratio combining (MRC) is used. For systems with luxurious link design for which the clearsky SNR is more than 30 dB, as considered in this paper, diversity and adaptive modulation do not significantly contribute to improvement of achievable transmission rate and BER performance. However, for systems with lower values of clear-sky SNR, use of both techniques will be more worthwhil.
Self-Tuning Pid Neural Network Controller to Control Nonlinear Ph Neutralization in Waste Water Treatment Hendra Cordova; Andry F. Wijaya
IPTEK The Journal for Technology and Science Vol 18, No 3 (2007)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v18i3.168

Abstract

The conventional PID control (linear) is popular control scheme that is used in almost pH control at waste water treatment process. pH model with respect to titration liquid flow rate has been known to be intrinsically difficult and nonlinear, especially when the process is conducted to non-linear range pH reference (pH 4-8), the settling time reach a long time. Therefore in this paper the nonlinear controller with self-tuning PID scheme is performed handle pH by training a neural-network based on backpropagation error signals. The pH process model is combination between CSTR (Continuous Stirred Tank Reactor) linear dynamic with H3PO4, HF, HCl, H2S flow rate and nonlinear static electro neutrality (wiener process model). The simulation result has a good and suitable performance under several tests (set-point and load change). The simulation result show the pH control system can follow the change of pH set-point and load with the average steady state error 0.00034. The settling time achieved at 50 second faster than conventional PID controller scheme.
Direct Method of the Minimum-Time Traversing and Hoisting Motion of the Container Crane Subchan, Subchan
IPTEK The Journal for Technology and Science Vol 18, No 3 (2007)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v18i3.170

Abstract

In this paper, a dynamic model of the container crane which represents simultaneous traversing and hoisting motions is discussed. The model is derived using Lagrangian modeling techniques. The problem is to minimize the transfer time of a container, where the optimal trajectory should satisfy the specified initial and terminal conditions and some constraints. The optimal control problem is transformed into sequence of nonlinear constrained optimization problems by discretising of the state and/or control variables. Numerical examples are provided, including the case where there is a singular-arc on control.
The Effect of Substrate Types to FAME Conversion on Acid-Catalyzed Transesterification of Crude Rice Bran Oil Orchidea Rahmaniah
IPTEK The Journal for Technology and Science Vol 18, No 3 (2007)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v18i3.169

Abstract

Biodiesel is an alkyl ester which is made from vegetable oils or animal fats. Indonesian biodiesel development is an urgent condition. The abundance of Indonesia’s natural sources is not manage well until now, such as rice bran. Rice bran oil is considered to be one of the most nutritious oils due to its favorable fatty acid composition and an unique combination of naturally occurring biologically active and antioxidant compounds. Acid catalyzed are the most suitable methods to produce biodiesel from high fatty acid rice bran oil. This present study was carried out to investigate the effects of substrate types from pure crude rice bran oil compounds on fatty acid methyl ester (FAME) formation. Experimental results shows, reaction rate of fatty acid to FAME was faster compare to triglyceride, incorporated 5%-H2O to pure triglyceride substrat didn’t increase the reaction rate. Rice bran oil high fatty acid content (15-70% FA) reached 85-98% conversion of FAME within 1 hour reaction, while oil with low fatty acid content (3-10% FA) only gives 25-75% conversion. The chain lengths, double bond, degree of saturation and chemical structure of fatty acid did not influence rate reaction of transesterification Fatty acids from different sources shows similar conversions and change in the fatty acids composition has no effect on rate of methanolysis.
Effect of Bamboo Node for Construction Application Basuki Widodo, Akhmad; Panunggal, Eko; Widjaja, Sjarief; M. Rasyid, Daniel; Soegiono, Soegiono
IPTEK The Journal for Technology and Science Vol 18, No 3 (2007)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v18i3.166

Abstract

In use of material for structure application, the most critical shares is jointed area, where this area is accumulation of stress accepted from existing burden. In structure laminate, joints represent part of drawback from the construction. And so do that happened at node in bamboo. Every part of bamboo there are node and internode. strength of bamboo with the internode will be downhill 25 % compared to bamboo without internode. In this research aim to know effect of bamboo node in construction laminate. Examination of test made with lamination without node and by node. Examination covering test of static bending and tensile strength. Standard used ASTM D-143. From result of examination and analyse, indicating that there difference between strength of wood laminate with internode and wood laminate without internode. But degradation of strength not equal to difference of strength of bamboo solid. At bamboo composite of degradation of strength only equal to 4.88 %, while wood and bamboo composites, where part of bamboo one-third from composite, degradation of strength reach 18.33 %. But degradation of the strength still fulfill conditions for structural used.

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