MAKARA Journal of Technology
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PLANT GROWTH MODELING USING L-SYSTEM APPROACH AND ITS VISUALIZATION
Get PDFThe visualizationof plant growth modeling using computer simulation has rarely been conducted with Lindenmayer System (L-System) approach. L-System generally has been used as framework for improving and designing realistic modeling on plant growth. It is one kind of tools for representing plant growth based on grammar sintax and mathematic formulation. This research aimed to design modeling and visualizing plant growth structure generated using L-System. The environment on modeling design used three dimension graphic on standart OpenGL format. The visualization on system design has been developed by some of L-System grammar, and the output graphic on three dimension reflected on plant growth as a virtual plant growth system. Using some of samples on grammar L-System rules for describing of the charaterictics of plant growth, the visualization of structure on plant growth has been resulted and demonstrated.Keywords: L-System, modeling, openGL, virtual plant growth, visualizatio
RESPONS GETARAN TORSIONAL POROS MODEL TURBIN ARUS LAUT SUMBU VERTIKAL AKIBAT EKSITASI MOMEN PUNTIR
Get PDFShaft Torsional Vibration Response of Vertical Axis Ocean Current Turbine Model Due to Torque Excitation. The current research aimed to study the torsional vibration response of Vertical Axis Ocean Current Turbine due torandomly torque excitation pattern, owing to the variety of ocean current velocity. The turbine model is composed of 3 aluminum blades of NACA 0018 connected to steel shaft. Turbine dimensions are 10 cm of chord, 1.8 cm of chamber and 100 cm of span. The variation of ocean current velocity is 0.5 m/s, 1.0 m/s, 1.5 m/s, 2.0 m/s, 2.5 m/s and 3.0 m/s. The Model has 2 degree of freedom which is described into two 2nd order differential equations. The eigenvalue solution yields the model’s natural frequencies; 201,38 rad/s and 457.91 rad/s. Fourier series is used to define the equation of torsional excitation, whilst the vibration equation is solved using Laplace Transform. According to analysis, there is no resonance occur. That because of the system’s natural frequencies is diverse to the magnitude of excitation frequencies. Model will be statically twisted first before vibrated. The response will be transient first then constantly steady. Furthermore, the bigger torque excitation will cause the bigger angular displacement as well the amplitude.Keywords: angular displacement, natural frequency, torsional vibration, vertical axis turbin
CONCEPT DESIGN AND TESTING OF MULTI-NOZZLE WATER MIST FIRE SUPPRESSION SYSTEM
Get PDFIn this work a flexible design of multi-nozzle arrangement of water mist fire suppression system was studied. The source of fire was a 65 mm diameter cooking oil fire. An investigation on the impact of nozzle arrangement on thetemperature profile of fires was conducted. The occurance of oil splash due to the application of water mist was also studied. The water mist systems developed in the present work can effectively extinguish cooking oil fires andprevented them from re-ignition. The spray angle, discharge pressure, and water flow rate were important factors to determine the effectiveness of water mist in extinguishing cooking oil fires.Keywords: cooking fires, fire safety engineering, fire suppression, multi nozzle design, water mis
CRADLE TO GATE SIMPLE LIFE CYCLE ASSESSMENT OF BIODIESEL PRODUCTION IN INDONESIA
Get PDFThe focus of this research is to analyze potential environmental impact in the supply chain of palm oil biodiesel industries. Simple Life Cycle Assessment (LCA) is applied to analyze impacts, produced by the three main units in the supply chain of Palm-Oil-based Biodiesel, which are Palm Plantation, CPO mill, and Biodiesel Plant. We developed LCA calculation model using spreadsheet software, used to assess a number of input scenarios to evaluate the best scenario, in variation of: land quality, land area and the rate of clearing, land clearing technique and type of the original land. The biggest potential environmental impact is the contribution to global warming impact which emissions are produced mostly from unit plantation. Although plantation has biggest potential to contribute to environmental impact, it also gives biggest reduction to global warming impact. In general, the biggest environmental impact in the LCA category is climate change, followed by photo-oxidant formation and eutrophication. The biggest impacts in the supply chain are from the plantation, especially when choosing the right technique for land clearing. In addition, due to LCA linearity nature, the scenario that we tested does not change the total accumulative environmental impacts.Keywords: environmental impact analysis, life cycle assessment, palm oil biodiese
NATURAL GAS AS PETROLEUM FUEL SUBSTITUTION: ANALYSIS OF SUPPLY-DEMAND PROJECTIONS, INFRASTRUCTURES, INVESTMENTS AND END-USER PRICES
Get PDFThe petroleum fuels (PF) subsidy has long burdens the government spending, and discourages less expensive energy usage such as natural gas (NG). Exporting NG and importing the more expensive PF products cause financial losses to Indonesia. The lack of NG infrastructure is the main hurdle in maximizing domestic NG usage and so does the perception of its high investment costs burdening government spending and pushing the NG transportation cost up. This study calculates the required NG infrastructure and its investments for several levels of PF substitutions up to 2030. To balance the NG demands, the supply from each field and its corresponding infrastructures needed was calculated and optimized using non-linear programming with generalized reduced gradient method to calculate the lowest transportation cost for the consumers. The study shows with a favorable return on investments attractive to private investors, the NG prices can still be put much lower than PF prices, allowing subsidy, import and production cost savings in many sectors. Furthermore, the highest level of substitution scenario needs only US 14.17 billion a year PF and electricity subsidy. Keywords: alternative energy, gas supply-demand, infrastructure cost, oil substitution, optimizatio
KARAKTERISASI PERMUKAAN ARANG AKTIF TEMPURUNG BIJI NYAMPLUNG
Get PDFCharacterization of Surface Active Shell Charcoal Nyamplung Seeds (Calophyllum inophyllum Linn). Chemical and physical activation of nyamplung shell with 0%, 5%, and 10% H3PO4 for 60 and 120 minutes has been carried out to prepare activated charcoal. The purpose of this experiment was to look into the characteristic of nyamplung shell activated charcoal surface. Nyamplung shell was carbonized into charcoal, then activated by immersion in H3PO4 solution using 0%, 5% and 10%, for 24 hours, and heated in retort at two temperatures (700 and 800 oC) and two duration (60 and 120 minutes). The material were characterized by fourier transform infra red (FTIR), scaning electron microscope (SEM) and X-ray diffraction (XRD). The FTIR spectrum show that activated charcoal has OH, C-H, C-O and C=C bonds. The bonds of OH and C-O indicated that the treatment was produced polar activated charcoal. The porous texture was influenced by H3PO4 concentration. The porous with dimension <5 μ being predominant at low concentration of H3PO4 (0% and 5%) but larger amount of H3PO4 (10%) produced wide pore with dimension >5 μ. Keywords: activated charcoal, FTIR, nyamplung shell, SEM, XR
ARE IEEE 754 32-BIT AND 64-BIT BINARY FLOATING-POINT ACCURATE ENOUGH?
Get PDFThis paper describes a research toward the accuracy of floating-point values, and effort to reveal the real accuracy. The methods used in this research paper are assignment of values, assignment of value of arithmetic expressions, and output the values using floating-point value format that helps reveal the accuracy. The programming-tool used are Visual C# 9, Visual C++ 9, Java 5, and Visual BASIC 9. These tools run on top of Intel 80x 86 hardware. The results show that 1*10-x cannot be accurately represented, and the approximate accuracy ranges only from 7 to 16 decimal digits. Keywords: accuracy, binary, floating-point, IEEE 75
TEKNIK PENGINDERAAN JAUH DAN SISTEM INFORMASI GEOGRAFIS UNTUK IDENTIFIKASI POTENSI KEKERINGAN
Get PDFRemote Sensing andGeographical Information System to Identify Drought Potency. Kebumen regency was drought in year 2008, community clean water shortages and irrigation water following a decline in water resources. The use of remote sensing data and GIS can be used to identify the potential for drought-prone areas. Transformation of Landsat TM satellite imagery to obtain the brightness index, wetness index and vegetation index used to determine surface conditions in relation to drought. Brightness index and wetness index derived from the tasseled cap modifications, while the vegetation index derived from normalized difference vegetation index (NDVI) values. Other parameters such as aquifer conditions, rainfall and other types of dry agricultural land use was a factor in identifying drought. The data are performed in accordance with the zone description in order to get the study area in relation to regional drought. The result of the research is identified area the district of Karangsambung, Karanggayam, Sadang, Alian, Puring, Klirong, Buluspesantren, Ambal and Mirit potential drought.Keywords: drought, GIS, Kebumen regency, remote sensin
PEMISAHAN SENYAWA TITANOMAGNETITE Fe3-xTixO4(o
Get PDFSeparation Study of Titanomagnetite Fe3-xTixO4 from Natural Sand at Indramayu, West Java. Titanomagnetite FeTiO4 has been obtained from metal sand which is separated from natural sand at Indramayu using magnetic separator with the magnetic field 0,3 Tesla. This method can improve titanomagnetite content from 32% to 63,6%. According to X-ray diffractometer (XRD) and data processing by general structure analyses system (GSAS) with χ2= 1,454 and Wrp = 0,1142 as correction factor of the peak to peak intensities, we conclude that χ2 about 0 and Wrp aproximately 10%. It indicates the datas with the error merely 0,1 can be accepted. Furthermore, HCl 32% and NH4OH 25% were added into separation result in order to increase titanomagnetite content. While X-ray flouresence (XRF) analyses shows weight fraction of titanomagnetite increase up to 100%.Keywords: GSAS, permanent magnetic, separation, titanomagnetite, XRD, XR
KARAKTERISTIK STABILITAS PEMECAH GELOMBANG KANTONG PASIR TIPE TENGGELAM
Get PDFThe Stability Characteristics of Sandbag Submerged Breakwater. Breakwater is one of coastal structures to overcome problems of abrasion. Due to difficulties in obtaining rock material at the coastal area. The using of sandbags as a breakwater provides advantages in utilizing local materials. A Sandbag has a smooth surface, so the internal shear forces are relatively small. According to these phenomena, the research for parameters that are expected to affect the stability of the sand bags. These parameters are a slope, shape and formation of sand bags. This experimental research conducted in two dimensional physical model and took place on the flume tank of Ocean Engineering Department, Faculty of Marine Technology, ITS. Scaled model 1 : 10. The bag was made in shapes, B1 and B2. Sand bags were prepared with the slope 1 : 1.5 and 1 : 2,0, width of top was 60 cm. The waves were regular waves, period of 1.5 seconds. The wave height was adjusted with the level of stability sand bags. It showed that the response of the sandbag was influenced by interlocking between sandbags. As a result, the stability depended on the change of wave forces, as a consequence of the change of slope and cross areas due to sandbags shape and formation type.Keywords: interlocking, internal friction, sandbag breakwate