MAKARA Journal of Technology
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APPLICATION OF EMPIRICAL ORTHOGONAL FUNCTION MODELS TO ANALYZE SHORELINE CHANGE AT BANGKALAN MADURA
Get PDFBangkalan’s shoreline, especially on the opposite side of Surabaya, has been evaluated to determine the morphological changes due to wave attack, near-shore current, long-shore sediment transport and coastal configuration. This research aims to determine the dominant patterns of variation of Bangkalan’s shoreline change, expressed by Eigen-function in empirical orthogonal function (EOF) models. That was started with data collection such as oceanographic data (wave and tidal), bathymetry and topographic map and sediment data. All data was used for forecasting two-monthly shoreline. Coordinate of two-monthly shoreline was used as input of EOF model. The first Eigen mode is a profile of shoreline equilibrium. The second Eigen mode shows pivot point that separates the different behaviors, which indicates a positive balance of shoreline from the direction of the dominant force. The models execution based on 1986’s shoreline show the shoreline change significantly at some cells e.g. around Suramadu bridge (cell 1-40), Batuporon (cell 70-100), Jungdima (cell 142-170) and at Kamal port (cell 230-250). The model of shoreline change using EOF was validated with the One-line model and data of 1995’s map’s shoreline. The E.O.F. value of model RMSE, 0.02, is less than the root mean square error (RMSE) value of One-line model, 0.04, which shows that the EOF model performance better than One-line models.Keywords: Bangkalan, Eigen-function, EOF, one-line model, shoreline chang
CASSAVA PULP AS A BIOFUEL FEEDSTOCK OF AN ENZYMATIC HYDROLYSIS PROCESS
Get PDFCassava pulp, a low cost solid byproduct of cassava starch industry, has been proposed as a high potential ethanolic fermentation substrate due to its high residual starch level, low ash content and small particle size of the lignocellulosic fibers. As the economic feasibility depends on complete degradation of the polysaccharides to fermentable glucose, the comparative hydrolytic potential of cassava pulp by six commercial enzymes were studied. Raw cassava pulp (12% w/v, particle size <320 μm) hydrolyzed by both commercial pectinolytic (1) and amylolytic (2) enzymes cocktail,yielded 70.06% DE. Hydrothermal treatment of cassava pulp enhanced its susceptibility to enzymatic cleavageas compared to non-hydrothermal treatment raw cassava pulp. Hydrothermal pretreatment has shown that a glucoamylase (3) was the most effective enzyme for hydrolysis process of cassava pulp at temperature 65 °C or 95 °C for 10 min and yielded approximately 86.22% and 90.18% DE, respectively. Enzymatic pretreatment increased cassava pulp vulnerability to cellulase attacks. The optimum conditions for enzymatic pretreatment of 30% (w/v) cassava pulp by apotent cellulolytic/ hemicellulolytic enzyme (4) was achieves at 50 °C for 3, meanwhile for liquefaction and saccharification by a thermo-stable α-amylase (5) was achieved at 95 °C for 1 and a glucoamylase (3) at 50 °C for 24 hours, respectively, yielded a reducing sugar level up to 94,1% DE. The high yield of glucose indicates the potential use of enzymatic-hydrothermally treated cassava pulp as a cheap substrate for ethanol production.Keywords: Cassava pulp, bio-alcohol feedstock, enzymatic hydrolysis, dextrose equivalent (DE
THE EFFECT OF RUBBER MIXING PROCESS ON THE CURING CHARACTERISTICS OF NATURAL RUBBER
Get PDFThis research is aimed at studying the relationship between rubber mixing processes and curing characteristics of natural rubber. The curing characteristic analysis was carried out through a natural rubber formula having been masticated and mixed, followed by curing. As many as four mastication methods were finely applied; each respected four sequences of rubber mixing process. In the first method, rubber was masticated for 5 minutes and then rubber chemicals and carbon black N 330 were simultaneously added. In the second and the third methods, rubber was masticated for 1 minute and then carbon blacks and rubber chemicals were also simultaneously added but using different type of fillers. In the fourth method, rubber was masticated for 3 minutes and then rubber chemicals and carbon black were subsequently added. The additions of rubber chemicals and carbon blacks to the masticated rubber were distinguished by the sequence and time allocated for each mixing process. The carbon blacks were added in two stages by which 10 phr was added first and the remaining 40 phr was added later along with oil. In another method, ratios of the carbon blacks addition (as done in the first and the second stages) were 20:30, 30:20, and 40:10. The examination results showed that rubber mixing process gave an impact on the changes of curing characteristics. They were much affected by the method of carbon black addition. The mixing temperature also had an effect on both curing time and curing rate in which the higher the mixing temperature, the lower the curing time and curing rate. Vulcanization temperature also affected the curing time and curing rate in which the higher the vulcanization temperature, the lower the curing time and the higher the curing rate. Lastly, particle size of carbon black also gave an impact on the curing time and curing rate in which the smaller the particle size, the lower the curing time and the higher the curing rate.Keywords: curing characteristics, natural rubber, rubber mixing proces
KNOWLEDGE DICTIONARY FOR INFORMATION EXTRACTION ON THE ARABIC TEXT DATA
Get PDFInformation extraction is an early stage of a process of textual data analysis. Information extraction is required to get information from textual data that can be used for process analysis, such as classification and categorization. A textual data is strongly influenced by the language. Arabic is gaining a significant attention in many studies because Arabic language is very different from others, and in contrast to other languages, tools and research on the Arabic language is still lacking. The information extracted using the knowledge dictionary is a concept of expression. A knowledge dictionary is usually constructed manually by an expert and this would take a long time and is specific to a problem only. This paper proposed a method for automatically building a knowledge dictionary. Dictionary knowledge is formed by classifying sentences having the same concept, assuming that they will have a high similarity value. The concept that has been extracted can be used as features for subsequent computational process such as classification or categorization. Dataset used in this paper was the Arabic text dataset. Extraction result was tested by using a decision tree classification engine and the highest precision value obtained was 71.0% while the highest recall value was 75.0%. Keywords: knowledge dictionary, information extraction, data text, Arabic tex
Electromagnetic Simulation for THz Antenna-Coupled Microbolometers Operated at Room Temperature
Get PDFRoom-temperature terahertz (THz) detectors with higher performance are necessary for utilizing the THz wave in various sensing, spectroscopy and imaging, but even the best ones in the present are still insufficient for the practical applications. This issue is essential especially in the region around 1 THz at which there exists a large technology gap between microwave and middle-infrared. Therefore, we study to develop an antenna-coupled microbolometer to achieve a high-performance THz detector operated at a room-temperature for sensing at around 1 THz frequency wave. In this paper, we present several important features and results obtained from electromagnetic simulations, which help to design a structure of the antenna and heater to absorb efficiently the power of THz wave.Keywords: detector, dipole antenna, electromagnetic simulation, microbolometer, terahertz (THz
Improvement in Performance of ZnO based DSC Prepared by Spraying Method
Get PDFThis paper reports the effect of TiCl4 on the performance of ZnO based DSC. ZnO was used due to its stability against photo-corrosion and photochemical properties similar to TiO2. Thin films of nanocrystalline ZnO were deposited on transparent conducting oxide glass using spray method. The ZnO films were treated using TiCl4. The cell’s efficiency was found to be 2.5% with TiCl4 post-treatment and 1.9% without TiCl4 post-treatment.Keywords: DSSC, ZnO, TiCl
Fatigue Life Prediction of the Keel Structure of A Tsunami Buoy Using Spectral Fatigue Analysis Method
Get PDFOne of the components of the Indonesia Tsunami Early Warning System (InaTEWS) is a surface buoy. The surface buoy is exposed to dynamic and random loadings while operating at sea, particularly due to waves. Because of the cyclic nature of the wave load, this may result in a fatigue damage of the keel structure, which connects the mooring line with the buoy hull. The operating location of the buoy is off the Java South Coast at the coordinate (10.3998 S, 108.3417 E). To determine the stress transfer function, model tests were performed, measuring the buoy motions and the stress at the mooring line. A spectral fatigue analysis method is applied for the purpose of estimating the fatigue life of the keel structure. Utilizing the model-test results, the S-N curve obtained in a previous study and the wave data at the buoy location, it is found that the fatigue life of the keel structure is approximately 11 years.Keywords: fatigue life, keel structure, spectral fatigue analysis, tsunami buoy 
PENDEKATAN ANALITIS DAN SIMULASI KOMPUTER DESAIN BLOK KACA RENDAH ENERGI
Get PDFAnalytical and Computational Simulation Approaches to Design Low Energy Glass Block. An environmentally friendly process was developed to produce a low embodied energy glass block from waste glasses. The energy efficiency of the glass block is represented by its thermal conductance (U) <3.177 W/m2.K and solar transmittance (SHGC) ≤0.25 as well as visible light transmission (VT) ≥0.27. A cavity was applied to reduce U value while insignificantly reducing VT. Analytical method was used to calculate the U value of glass blocks, ignoring the effect of convection. Ecotect program was used to analyze light level (VT) and heat load (SHGC) of each model. Effect of convection was simulated using a CFD program, which showed air velocity inside the cavity and temperature gradient in glass blocks. Comparing to an application with 3 mm float glass, energy efficiency obtained through applying the glass blocks could reach 96%. This simulation study ignored the presence of adhesive among glass layers that potentially reduces the VT and the SHGC of the glass blocks.Keywords: analytical approach, cavity, computational simulation, glass block, low energ
SAMBUNGAN LENTUR SEBAGAI PENAHAN BENTURAN DUA GEDUNG TINGGI YANG DIBANGUN BERDAMPINGAN
Get PDFFlexible Connection Elastomeric Rubber as a Pounding Resisting Element between Two Adjacent Buildings To solve pounding problem of two adjacent buildings, structural designer usually employs a dilatation between the structures or make the two structures as a monolith structure. Other alternative is by using an elastomeric rubber as a pounding resisting element between the two structures. Effectiveness in applying elastomeric rubber component as flexible connection of two adjacent structures is the main focus of this paper. Various simulations such as structure models, earthquake excitations and openings in gap element are studied. Observation of maximum structural responses will be performed for structure model with elastomeric rubber in comparison with (1) monolith structure model and (2) structure model with rigid element (steel element). Simulation results show that application of elastomeric rubber component to prevent structures from pounding problem provides advantages especially in reducing internal forces in the shorter building. However, it slightly increases displacement of both structures.Keywords: elastomeric rubber, dilatation, flexible connection, poundin
ALOS/PALSAR IMAGE PROCESSING USING DINSAR AND LOG RATIO FOR FLOOD EARLY DETECTION IN JAKARTA BASED ON LAND SUBSIDENCE
Get PDFFlood that occurred in Jakarta is not only influenced by rainfall, urban planning system and drainage alone, but also may be involved land subsidence (LS). LS is possible in because Jakarta stands on top of layers of sediments and the presence of ground water consumption in very large quantities. In this research, the Advanced Land Observing Satellite (ALOS)/Phased Array type L-band Synthetic Aperture Radar (PALSAR) data was processed to determine the level of LS in Jakarta area and its relation to flood potential area. Differential interferometry method (DInSAR) was performed on two PALSAR data with different acquisition years, i.e. 2007 and 2008, respectively. DInSAR processing generated images containing information that can be converted into LS. To find the elevation changing area, log ratio algorithm was applied to those images as the additional analysis. The log ratio image is superimposed on the DInSAR result andJakarta inundation map of 2009, to acquire the relationship between LS and the flood and flood vulnerability map of Jakarta based on LS. It is found that lands on the flooded area of 10.57 cm on the average, with a minimum and maximum of 5.25 cm and 22.5 cm, respectively. The greater the value of LS, inundation area also tend to widen, except in a few areas that have special conditions, such as reservoirs, river flow solution, water pump system and sluices. Accuracy of DInSAR result image is quite high, with the difference of 0.03 cm (0.18%) to 0.55 cm (3.37%) as compared to those from GPS measurements. These results can be recommended to the local government of Jakarta to minimize the potential risk of flood, as well as the subject of city planning for the future.Keywords: ALOS/PALSAR, DInSAR, flood potential area, land subsidence (LS), log rati