IPTEK The Journal for Technology and 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.
Articles
345 Documents
<![CDATA[Plane Wall Effect of Flow around Two Circular Cylinders in Tandem Arrangement ]]>
<![CDATA[Triyogi Yuwono]]>;
<![CDATA[Wawan Aries Widodo]]>;
<![CDATA[Heru Mirmanto]]>;
<![CDATA[Fahmi Fahreza]]>
<![CDATA[ IPTEK The Journal for Technology and Science Vol 22, No 1 (2011) ]]>
Publisher : <![CDATA[IPTEK, LPPM, Institut Teknologi Sepuluh Nopember ]]>
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DOI: 10.12962/j20882033.v22i1.56
<![CDATA[The flow characteristic around two circular cylinders in tandem arrangement located near a plane wall were investigated experimentally in a uniform flow at a Reynolds Number of 5.3 x 104. The center to center spacing between the two cylinders relative to the cylinder diameter was constantly maintained at P/D = 1.5. The pressure distributions along the surface of the cylinder and the plane wall were measured by varying the gap-to-diameter of cylinder ratio (G/D) in the range of 0 < G/D < 0.467. Surface oil-film techniques were used to investigate the flow patterns on the cylinder. The result showed that for upstream cylinder, in the gap-to-diameter ratio G/D < /D, there is no stagnation point at front side of the upstream cylinder; it is gradually raised as the gap increase. For the downstream cylinder, a peak on the lower side of the front side of the cylinder is apparent in each of the pressure distributions. This peak represents the reattachment of shear layer that separates from lower side of the upstream cylinder. The reattachment point tends to move forward close to the angular position of = 0o as the gap ratio increase. The shear layer bifurcates into two shear layers. One shear layer continues in the downstream direction, and the other shear layer flows in the upstream direction.]]>
<![CDATA[Dynamic and Geological-Ecological Spatial Planning Approach in Hot Mud Volcano Affected Area in Porong-Sidoarjo ]]>
<![CDATA[Haryo Sulistyarso]]>
<![CDATA[ IPTEK The Journal for Technology and Science Vol 21, No 3 (2010) ]]>
Publisher : <![CDATA[IPTEK, LPPM, Institut Teknologi Sepuluh Nopember ]]>
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DOI: 10.12962/j20882033.v21i3.92
<![CDATA[By May 29t h 2006 with an average hot mud volcano volume of 100,000 m3 /per day, disasters on well kick (i.e. Lapindo Brantas Ltd.) in Banjar Panji 1 drilling well have deviated the Spatial Planning of Sidoarjo’s Regency for 2003- 2013. Regional Development Concept that is aimed at developing triangle growth pole model on SIBORIAN (SIdoarjo-JaBOn-KRIaAN) could not be implemented. This planning cannot be applied due to environmental imbalance to sub district of Porong that was damaged by hot mud volcano. In order to anticipate deviations of the Regional and Spatial Planning of Sidoarjo Regency for 2003-2013, a review on regional planning and dynamic implementation as well as Spatial Planning Concept based on geologicalecological condition are required, especially the regions affected by well kick disaster. The spatial analysis is based on the geological and ecological condition by using an overlay technique using several maps of hot mud volcano affected areas. In this case, dynamic implementation is formulated to the responsiblity plan that can happen at any time because of uncertain ending of the hot mud volcano eruption disaster in Porong. The hot mud volcano affected areas in the Sidoarjo’s Spatial Planning 2009-2029 have been decided as a geologic protected zone. The result of this research is scenarios of spatial planning for the affected area (short term, medium term and long term spatial planning scenarios).]]>
<![CDATA[Synthesis and Characterization of Low Loading MoO3/Ts-1 Catalyst ]]>
<![CDATA[Suci Indrayani]]>;
<![CDATA[Didik Prasetyoko]]>
<![CDATA[ IPTEK The Journal for Technology and Science Vol 19, No 4 (2008) ]]>
Publisher : <![CDATA[IPTEK, LPPM, Institut Teknologi Sepuluh Nopember ]]>
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DOI: 10.12962/j20882033.v19i4.144
<![CDATA[Abstract⎯Molybdenum oxide (MoO3) have been introduced to titanium silicalite (TS-1) by impregnation methode and have been characterized with X-ray diffraction (XRD), infrared spectroscopy, nitrogen and pyridine adsorption. The results show that TS-1 and XMoO3/TS-1 have orthorhombic structure and MFI framework structure type. 0,5% MoO3/TS-1, dan 1% MoO3/TS-1 catalyst have not been yet Brønsted acid site, while Brønsted acidity increased from 2% MoO3/TS-1 to 4% MoO3/TS-1 respectively.]]>
<![CDATA[Concrete Failure Modeling Based on Micromechanical Approach Subjected to Static Loading ]]>
<![CDATA[Endah Wahyuni]]>
<![CDATA[ IPTEK The Journal for Technology and Science Vol 21, No 1 (2010) ]]>
Publisher : <![CDATA[IPTEK, LPPM, Institut Teknologi Sepuluh Nopember ]]>
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DOI: 10.12962/j20882033.v21i1.22
<![CDATA[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.]]>
<![CDATA[Multi-Responses Optimization Of Edm Sinking Process Of Aisi D2 Tool Steel Using Taguchi Grey–Fuzzy Method ]]>
<![CDATA[Bobby Oedy Pramoedyo Soepangkat]]>;
<![CDATA[Arif Wahyudi]]>;
<![CDATA[Bambang Pramujati]]>
<![CDATA[ IPTEK The Journal for Technology and Science Vol 25, No 2 (2014) ]]>
Publisher : <![CDATA[IPTEK, LPPM, Institut Teknologi Sepuluh Nopember ]]>
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DOI: 10.12962/j20882033.v25i2.528
<![CDATA[Rough machining with Electro Discharge Machining (EDM) process gives a large Material Removal Rate (MRR) and high Surface Roughness (SR), while finish machining gives low SR and very slow MRR. In this study, Taguchi method coupled with Grey Relational Analysis (GRA) and fuzzy logic has been applied for optimization of multiple performance characteristics. The EDM machining parameters (gap voltage, pulse current, on time and duty factor) are optimized with considerations of multiple performance characteristics, i.e., MRR and SR. The quality characteristic of MRR is larger-is-better, while the quality characteristic of SR is smaller-is-better. Based on Taguchi method, an L18 mixed-orthogonal array is selected for the experiments. By using the combination of GRA and fuzzy logic, the optimization of complicated multiple performance characteristics was transformed into the optimization of a single response performance index. The most significant machining parameters which affect the multiple performance characteristics were gapvoltage and pulse current. Experimental results have also shown that machining performance characteristics of EDM process can be improved effectively through the combination of Taguchi method, GRA and fuzzy logic.]]>
<![CDATA[Mixing Urea and Zeolite for Slow Release Fertilizer using Orbiting Screw Mixer ]]>
<![CDATA[Semuel Pati Senda]]>;
<![CDATA[Renanto Handogo]]>;
<![CDATA[Achmad Roesyadi]]>;
<![CDATA[Wahono Sumaryono]]>
<![CDATA[ IPTEK The Journal for Technology and Science Vol 20, No 4 (2009) ]]>
Publisher : <![CDATA[IPTEK, LPPM, Institut Teknologi Sepuluh Nopember ]]>
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DOI: 10.12962/j20882033.v20i4.83
<![CDATA[Slow release fertilizer (SRF) of urea is prepared by using zeolite as the matrix. Mixing of urea and zeolite is carried out in orbiting screw mixer. The effects of rotation speed and orbital speed of the mixer and particle size on power consumption, homogeneity, mixing time and specific energy consumption are evaluated. The experimental results show that higher orbital speed gives higher power consumption. Power consumption is dominated by mixer rotation motion. Smaller particle size needs higher power for mixing process. Nitrogen mass fraction ranges from 0.45 to 0.49 when mixture reaches homogeneity. The mixing time required is about 5 – 12 minutes for particle size of >60 and >80 mesh and 7 – 14 minutes for particle size of >50 mesh. At constant orbit speed, the higher the screw rotation speed, the shorter time needed to reach mixture homogeneity. Specific energy consumption of mixing process increases with decreasing particle size. For the three particle size groups of >80 mesh, >60 mesh and >50 mesh, the lowest specific energy consumption is given by combination of orbital speed of 5 rpm and rotation speed of 50 rpm; while for particle size of >60 mesh and >80 mesh, it can obtained by combination of orbital speed of 5 rpm and rotation speed of 67,5 rpm and orbital speed 5 rpm and rotation speed 30 rpm, respectively. The lowest specific energy consumptions is gained by combination of orbital and rotation speeds of 5 and 50 rpm with particle size of >50 mesh.]]>
<![CDATA[Ligninolytic Enzymes Produced by Gliomastix sp. in an Organic Waste Medium ]]>
<![CDATA[Nengah Dwianita Kuswytasari]]>;
<![CDATA[Maya Shovitri]]>;
<![CDATA[Enny Zulaika]]>
<![CDATA[ IPTEK The Journal for Technology and Science Vol 26, No 1 (2015) ]]>
Publisher : <![CDATA[IPTEK, LPPM, Institut Teknologi Sepuluh Nopember ]]>
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DOI: 10.12962/j20882033.v26i1.577
<![CDATA[Ligninolytic enzymes are extracelluler enzymes that have many benefit on multiple industrial department. Its can result from Gliomastix sp. This study was aimed to determine the effect of temperature and pH on the activity of Ligninolytic enzymes by Gliomastix sp. T3.7 that grow on multiple organic waste . Ligninolytic enzymes was measured with spectrofotometer UV-Vis Boeco S22. The result showed that Gliomastix sp. T3.7 potentially produce the ligninolytic enzymes like as laccase, LiP and MnP. The optimum laccase activity ( 1,765 U/ml) detected on sugarcane baggase waste, pH 6 and temperature of 350C . The optimum LiP activity (8,088U/ml) detected on corn cobs, pH 5 and 350C, whereas the optimum MnP activity (0,964 U/ml) detected on sugarcane baggase too. Its optimum on pH 4 and 250C. Gliomastix sp. T3.7 on sugarcane bagasse, pH 6 and 350C, agensia potentially used as remediation on a variety of industry pollution.]]>
<![CDATA[Addressing Palm Biodiesel as Renewable Fuel for the Indonesian Power Generation Sector: Java-Madura-Bali System ]]>
<![CDATA[Natarianto Indrawan]]>;
<![CDATA[Muhammad Ery Wijaya]]>
<![CDATA[ IPTEK The Journal for Technology and Science Vol 22, No 4 (2011) ]]>
Publisher : <![CDATA[IPTEK, LPPM, Institut Teknologi Sepuluh Nopember ]]>
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DOI: 10.12962/j20882033.v22i4.79
<![CDATA[Energy security defined as how to equitably provide available, affordable, reliable efficient, environmentally friendly, proactively governed and socially acceptable energy services to end user. It has in recent years taken attention of policymakers in different parts of the world. Formulating policy to improve energy security is mandatory, not only because of depleting fossil resource, but also implementing diversity of energy source since utilization abundant renewable energy resources can increase the security of energy supply. One of the abundant renewable energy resources in Indonesia is palm oil. This study analyses the utilization of palm biodiesel for Indonesian power generation sector in the Java-Madura-Bali (JAMALI) system. Two scenarios were created by projecting the demand and environmental impact as well as GHG emissions reduction over the next 25 years. The first scenario subjects on current energy policy, while the second scenario is to substitute of fossil fuel which is still used in the JAMALI power generation system. Effect of palm biodiesel on emission of Carbon Dioxide, Carbon Monoxide, Sulfur Dioxide, Nitrogen Oxides, Particulate Matter, and Volatile Organic Compounds were estimated for each scenario. An externality analysis to complete the environmental analysis was conducted and resource analysis of palm oil plantation based biodiesel was also estimated. Finally, the economics feasibility of palm biodiesel in the power generation sector was analyzed.]]>
<![CDATA[The Expert Control Designing of Tanker Ship Maneuvering by Optimal Control as a Reference Model ]]>
<![CDATA[Aulia S. Aisjah]]>
<![CDATA[ IPTEK The Journal for Technology and Science Vol 20, No 1 (2009) ]]>
Publisher : <![CDATA[IPTEK, LPPM, Institut Teknologi Sepuluh Nopember ]]>
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DOI: 10.12962/j20882033.v20i1.133
<![CDATA[Fuzzy logic control (FLC) system is a control system which is working based on error input data, rate of error, and accelaret of error of controlling variable. Using some rules of FAM (Fuzzy Associate Memory) which is constructed for resulting a decision can be used to actuator of controller. This paper is des-cribing about designing fuzzy logic as a control system for ship maneuvering, which is input for FLC are yaw error, yaw rate, and tracking error while the output of fuzzy logic control is command rudder signal. FLC con-sists of two units of controller; it is first controller unit work for autopilot and second controller unit for offset track. Interference function for FLC is Sugeno – Takagi which represent mathematic equation from input vari-able of FLC. Gain control of FLC based on least square estimation of error yaw, yaw rate, and output control signal relationship from LQR/LTR as a model reference control. Dynamic model of ship maneuvering has been derived on 3 dof with Clarke hydrodynamic coefficient. The capability of logic fuzzy control has been shown on simulation, for tanker ship model without interference or within interference. Robust of fuzzy logic control has been got from trajectory convergence error of yaw and yaw rate error when on turning simulation or off turning simulation toward the sector (0, 0).]]>
<![CDATA[Empirical Bayesian Method for the Estimation of Literacy Rate at Sub-district Level Case Study: Sumenep District of East Java Province ]]>
<![CDATA[A.Tuti Rumiati]]>;
<![CDATA[Khairil Anwar Notodiputro]]>;
<![CDATA[Kusman Sadik]]>;
<![CDATA[I Wayan Mangku]]>
<![CDATA[ IPTEK The Journal for Technology and Science Vol 23, No 1 (2012) ]]>
Publisher : <![CDATA[IPTEK, LPPM, Institut Teknologi Sepuluh Nopember ]]>
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DOI: 10.12962/j20882033.v23i1.13
<![CDATA[This paper discusses Bayesian Method of Small Area Estimation (SAE) based on Binomial response variable. SAE method being developed to estimate parameter in small area due to insufficiency of sample. The case study is literacy rate estimation at sub-district level in Sumenep district, East Java Province. Literacy rate is measured by proportion of people who are able to read and write, from the population of 10 year-old or more. In the case study we used Social Economic Survey (Susenas)data collected by BPS. The SAE approach was applied since the Susenas data is not representative enough to estimate the parameters at sub-district level because it’s designed to estimate parameters in regional area (in scope of a district/city at minimum). In this research, the response variable being used was logit function trasformation of pi (the parameter of Binomial distribution). We applied direct and indirect approach for parameter estimation, both using Empirical Bayes approach. For direct estimation we used prior distribution of Beta distribution and Normal prior distribution for logit function (pi) and to estimate parameter by using numerical method, i.e integration Monte Carlo. For indirect approach, we used auxiliary variables which are combinations of sex and age (which is divided into five categories). Penalized Quasi Likelihood (PQL) was used to get parameter estimation of SAE model and Restricted Maximum Likelihood method (REML) for MSE estimation. Instead of Bayesian approach, we are also conducting direct estimation using classical approach in order to evaluate the quality of the estimators. This research gives some findings, those are: Bayesian approach for SAE model gives the best estimation because having the lowest MSE value compares to the other methods. For the direct estimation, Bayesian approach using Beta and logit Normal prior distribution give a very similar result to the direct estimation with classical approach since the weight of is too large, which is about 0.905. It is also found that direct estimation using Bayesian approach with the Beta prior distribution gives better MSE than using logit normal prior distribution.]]>
