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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.
Arjuna Subject : -
Articles 5 Documents
Search results for , issue "Vol 30, No 1 (2019)" : 5 Documents clear
Steam Coil Air Heater (SCAH) Modelling as Porous Medium to Analyze Flow Characteristic and Reduce Self Energy Usage in Gresik Unit 1 Steam Power Plant Eko Ariyanto; Wawan Aries Widodo
IPTEK The Journal for Technology and Science Vol 30, No 1 (2019)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (604.39 KB) | DOI: 10.12962/j20882033.v30i1.4993

Abstract

This study deals with flow and heat transfer characteristic in a Heat Exchanger if its tube modules completely or partially dismantled. The heat exchanger is a Steam Coil Air Heater (SCAH) Installed in Gresik unit 1 Steam Turbine Power Plant. Nowadays the power plant operate mostly utilized natural gas as a fuel. When it utilized natural gas SCAH are not give benefit and only give flow resistance for combustion air flow. This study use numerical simulation model with commercial Computational Fluid Dynamic (CFD) software. The simulation on 3D model with steady state flow condition. The model use energy model, Heat Exchanger Model, realizable k-Epsilon for turbulence viscous model and SCAH model as Porous Medium (PM). Modelling SCAH as a PM will avoid time consuming mesh generation and simulations with high CPU usage. Fives scenarios of tube module dismantling simulated in 100% load. This study result both quantitative and qualitative data coresspond with flow and heat transfer characteristic. The model with original scenarios give good result in terms of pressure and outlet temperature with commisioning data. The contour data results show there are several secondary flow due to enlargement of flow area. Numerical results of variation S1,S2,S3,S4 are indicated decreasing total pressure drop about 32.27%, 51.29%, 47.04%, 65.25% respectively. And temperature rise for each schenario will decrease to 29.29% (S1), 46.51% (S2) , 47.92% (S3), 68.28% (S4) respectively,except for S5 have no pressure drop and temperature rise since all module are dismantled.
Fatigue Life of Mooring Lines on External Turret Floating LNG for Different Pretension and Water Depth Norman Mahdar Sabana; Eko Budi Djatmiko; Rudi Walujo Prastianto
IPTEK The Journal for Technology and Science Vol 30, No 1 (2019)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (651.295 KB) | DOI: 10.12962/j20882033.v30i1.5009

Abstract

This paper studies fatigue life of mooring lines applied on turret-moored Floating LNG (Liquefied Natural Gas). Several case studies were designed to investigate the influence of mooring pretension and water depth on the fatigue life of mooring lines. Floating LNG with permanent external turret mooring system consists of 12 catenary lines arranged in 3 group with 4 lines each. Time domain simulation applied to calculated coupled dynamic response and mooring tension. Fatigue life is assessed using rainflow counting method, T-N curves and Palmgren-Miner rule. Analysis results for mooring pretension case show that case study 2 with lowest pretension (14%MBL) yields shortest mooring fatigue life of 1814.20 years compared to case study 1 (18%MBL) and 3 (22%MBL) with 2034.61 years and 2983.33 years respectively. Despite has the lowest dynamic line tension, case study 2 has larger tension range that results in the increased of fatigue damage. The increase in water depth will increase the mooring line length and its weight, so it results in the increase of fatigue damage. This is reflected in case study 5 (903m water depth), which has shortest mooring fatigue life of 1842.65 years compare to case study 1 (602m water depth) and 4 (301m water depth) with 2983.33 years and 3363.62 years respectively.
Identification of Soil Contamination using VLF-EM and Resistivity Methods: A Case Study Rahmatun Inayah; Bagus Jaya Santosa; Dwa Desa Warnana; Firman Syaifuddin; Juan Pandu Gya Nur Rochman; Wien Lestari; Amien Widodo
IPTEK The Journal for Technology and Science Vol 30, No 1 (2019)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (652.116 KB) | DOI: 10.12962/j20882033.v30i1.5004

Abstract

Hazardous waste is a waste with properties which can pollute and damage the environment, human health, and other living things. Lakardowo is a village that is suspected of being contamination by hazardous waste derived from industrial activities. Measurements with the VLF-EM and Resistivity method were used in this study. In addition, ground water level mapping and soil sampling in locations around the industry were conducted for the XRF test. Groundwater mapping results show that groundwater flow lead to the Northeast-South and Southwest of the industrial site. The soil samples that have been tested by XRF show the presence of heavy metals, wherein hazardous wastes generally contain various types of heavy metals that are conductive or have low resistivity values. Quantitative interpretation of VLF-EM data shows the presence of low resistivity anomalies at several measurement sites, which are suspected to have been contaminated with soil by waste. Resistivity data processing results, showing a low resistivity anomaly (≤ 3 Ω.m) located to the north (near an industrial site) and spreading towards the southwest along the measurement path. The result of a combination of quantitative interpretations of both methods, obtained, the direction of anomalous flow of hazardous waste moves southeastward and towards deeper soil coating following the direction of rock coating.
Decision Analysis of Giving Credit Using Pairwise Comparisons and Scoring Methods (Case Study: Bank XYZ) Priangga, Prima; Suryani, Erma
IPTEK The Journal for Technology and Science Vol 30, No 1 (2019)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (664.416 KB) | DOI: 10.12962/j20882033.v30i1.4664

Abstract

Kredit Usaha Rakyat (KUR) is a type of credit was given by Bank for segmen business Micro, Small and Medium Enterprises (UMKMK). Along with the high interest of the community in applying for credit to the Bank, it raises its own problems, namely determining the feasibility of customers. Determining this feasibility is important considering that KUR is one of the Government's programs in empowering the UMKMK industry sector, so that the risk of non-performing loans is expected to be minimized. The method used in this study is the Pairwise Comparisons and Scoring, based on the consideration that Pairwise Comparisons and Scoring are aids in priority of criteria, priority of sub criteria and giving scoring to determine lending decisions. Pairwise Comparisons are the basic concepts of the Analytical Hierarchy Process which have been proven to solve decision problems which involve many complex criteria. The results obtained in this study are priority of criteria, priority of sub criteria and scoring of debtors for the determination of debtors who are eligible or not eligible for receive credit. 30 debtors who were sampled in this study, 17 debtors were eligible to receive credit and 13 debtors were not eligible to receive credit.
Study of Remu River Water Quality Using Dynamic Program Thenu, Lebrina; Karnaningroem, Nieke
IPTEK The Journal for Technology and Science Vol 30, No 1 (2019)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (517.333 KB) | DOI: 10.12962/j20882033.v30i1.4998

Abstract

Remu River has been being a water resource for residents in Sorong City. Development in this city lead to water quality degradation of Remu River. Existing (2016) and prediction condition of Remu River in the next 2 years were defined by the behavior of BOD, COD, Fe, and DO that proceed using a dynamic program, STELLA 9.1.3. Study area involved 6 sampling points. Simulation results showed that BOD, COD, and Fe concentrations tend to increase in the next 2 years, even BOD and COD concentrations at several sampling points was higher than water quality standard, according to Government Regulation No. 82/2001. Meanwhile, DO concentration was below the limit in 4th to 6th sampling points. Pollution control strategy was conducted by setting up three scenarios: (1) procurement of Waste Water Treatment Plant (WWTP), (2) river sediment dredging, and (3) combination of both scenario. Combination of sediment dredging and procurement of WWTP scenario estimated to reduce BOD concentration to 89.82%, COD concentration to 87.02%, and increase DO concentration to 19.07%. So that, the 3rd scenario was determined as the best strategy to improve Remu River water quality, although Fe concentration cannot be controlled as it comes from nature.

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