IPTEK: The Journal for Technology and Science 

About: IPTEK: The Journal for Technology and Science is an academic journal published by Institute for Research and Public Services. The journal publishes majorly in the area(s): Computer science & Catalysis. It has an ISSN identifier of 0853-4098. It is also open access. Over the lifetime, 281 publications have been published receiving 691 citations. The journal is also known as: The Journal for Technology and Science & Majalah Ilmu Pengetahuan dan Teknologi Institut Teknologi Sepuluh Nopember 1945 Surabaya.

A Review of Solar-Powered Boat Development

Abstract: Research in the application of renewable energy has intensified in recent years. The possibility of petroleum extinction in the future is forcing researchers to enhance the utilization of renewable energy resources as substitute for fossil fuel-based technologies in all fields. Ships as one of the most important transportation in the world also require diesel oil as fuel for main propulsion systems and for diesel generators which supply electrical needs. Solar energy has been considered as the most suitable renewable energy resources to substitute the role of fuel in the ships. In this paper, the latest research on the utilization of solar energy in the ship are presented and analyzed to provide information for the researchers who developed the technology of solar-powered boat

Estimation of Total Suspended Sediment and Chlorophyll-A Concentration from Landsat 8-Oli: The Effect of Atmospher and Retrieval Algorithm

Abstract: Total Suspended Sediment (TSS) and Chlorophyll-a (Chl-a) are globally knows as a key parameters for regular seawater monitoring. Considering the high temporal and spatial variation of water constituent, remote sensing technique is an efficient and accurate method for extracting water physical parameter. A high accurate estimated data derived from remote sensing depends on an accurate atmospheric correction algorithm and physical parameter retrieval algorithms. In this research, we evaluated the accuracy of atmospheric corrected product of NASA as well as develop algorithms for estimating TSS and Chl-a concentration over Poteran and Gili Iyang island water using Landsat-8 OLI data. The data used in this study was collected from Poteran’s waters (9 stations) on April 22, 2015 and Gili Iyang’s waters (six stations) on October 15, 2015. Low correlation between in situ and Landsat Rrs(λ) (R2= 0.106) indicated that atmospheric correction algorithm performed by NASA has a limitation. The TSS concentration retrieval algorithm produced acceptable accuracy both over Poteran’s Waters (RE of 4.60% and R2 of 0.628) and over Gili Iyang’s waters (RE of 14.82% and R2 of 0.345). Although the R2 lower than 0.5, the relative error was more accurate than the minimum requirement of 30%. Whereas, The Chl-a concentration retrieval algorithm produced acceptable result over Poteran (RE of 13.87% and R2 of 0.416) and failed over Gili Iyang’s waters (RE of 99.140 and R2 of 0.090). The low correlation between TSS or Chl-a measured and estimated TSS or Chl-a concentration were caused not only by performance of the developed TSS and Chl-a estimation retrieval algorithm but also the effect and accuracy of atmospheric corrected reflectance of Landsat product.

Development of geopolymer concrete with different curing conditions

Abstract: Environmental issues resulted from cement production have become a major concern today. To develop a sustainable future it is encouraged to limit the use of this construction material that can affect the environment. Cement replacement material was proposed to partially replace cement portion in concrete. Geopolymer is a part of inorganic polymer material that has similar bonding function like cement in concrete. It consists of alkaline solutions and geological source material. Alkaline liquids used in this research are 8 M sodium hydroxide (NaOH) solution and sodium silicate (Na2SiO3) solutions, while source materials are fly ash and microwave incinerated rice husk ash (MIRHA). Three different curing regimes, namely hot gunny curing, ambient curing, and external exposure curing, were applied to obtain suitable method that was suitable with cast in situ application. Geopolymer concrete samples were tested on their compressive strength and microstructure properties. It was found that external exposure curing had the highest compressive strength compared to other two curing methods. Scanning electron microscopy analysis also showed better improvement in interfacial transition zone for concrete sample with external exposure curing.

Ocean Wave Characteristics in Indonesian Waters for Sea Transportation Safety and Planning

Abstract: This study was aimed to learn about ocean wave characteristics and to identify times and areas with vulnerability to high waves in Indonesian waters. Significant wave height of Windwaves-05 model output was used to obtain such information, with surface level wind data for 11 years period (2000 to 2010) from NCEP-NOAA as the input. The model output data was then validated using multimission satellite altimeter data obtained from Aviso. Further, the data were used to identify areas of high waves based on the high wave’s classification by WMO. From all of the processing results, the wave characteristics in Indonesian waters were identified, especially on ALKI (Indonesian Archipelagic Sea Lanes). Along with it, which lanes that have high potential for dangerous waves and when it occurred were identified as well. The study concluded that throughout the years, Windwaves-05 model had a magnificent performance in providing of ocean wave characteristics information in Indonesian waters. The information of height wave vulnerability needed to make a decision on the safest lanes and the best time before crossing on ALKI when the wave and its vulnerability is likely low. Throughout the years, ALKI II is the safest lanes among others since it has been identified of having lower vulnerability than others. The knowledge of the wave characteristics for a specific location is very important to design, plan and vessels operability including types of ships and shipping lanes before their activities in the sea

Automatic Segmentation of Impaired Joint Space Area for Osteoarthritis Knee on X-ray Image using Gabor Filter Based Morphology Process

Abstract: Segmentation is the first step in osteoarthritis classification. Manual selection is time-consuming, tedious, and expensive. The system is designed to help medical doctors to determine the region of interest of visual characteristics found in knee Osteoarthritis (OA). We propose a fully automatic method without human interaction to segment Junction Space Area (JSA) for OA classification on impaired x-ray image. In this proposed system, right and left knee detection is performed using using Contrast-Limited Adaptive Histogram Equalization (CLAHE) and template macthing. The row sum graph and moment methods are used to segment the junction space area of knee. Overall we evaluated 98 kneess of patients. Experimental results demonstrate an accuracy of the system of up to 100% for detection of both left and right knee and for junction space detection an accuracy 84.38% for the right knee and 85.42% for the left. The second experiment using gabor filter with parameter α=8, θ=0, Ψ=[0 Π/2], γ=0,8 and N=8 and row sum graph give an accuracy 92.63% for the right knee and 87.37% for the left. And the average time needs to process is 65.79 second. For obvious reasons we chose the results of the fourth to segment junction area in both right and the left knee.