MAKARA Journal of Technology
Not a member yet
243 research outputs found
Sort by
THE SELECTION OF MATERIALS FOR ROLLER CHAINS FROM THE PERSPECTIVE OF MANUFACTURING PROCESS
Get PDFThe selection of materials for an engineering component is not only requested by its design function and shape, but alsothe sequence through which it is manufactured. The manufacturing operation of roller chains involves drawing andtrimming processes aimed at producing semi-finished chain drives component with a well-standardized dimension. Inaddition to final combination of properties required by design constraints, the ability of materials to be formed into adesired shape and geometry without failure is also critical. The objective of materials selection should therefore involveadditional attributes that are not typically accommodated by the standard procedure of materials selection. The presentpaper deals with the selection of materials for roller chains from the perspective of manufacturing process. Ears andun-uniform wall thickness have been identified as a key problem in the mass production of component. Provided allprocess parameters were established, the anisotropy factor of materials is critical. Simulative test can be reasonablyused to obtain material performance indices that can be added up to the standard procedure of material selection. Ofthree commercially available steel grades evaluated with regard to the criteria defined, one grade is more suitable for thepresent objective.Keywords: roller chains, materials selection, manufacture, drawing, trimming, ears
STUDI EFEK ELEKTROKROMIK PADA FILM POLIANILIN
Get PDFStudy on Electrochromic Effect of Polyaniline Film. The light transmission factor of an electrochromic film changesreversibly with the application of an electrical voltage. Thereby the transparent film becomes reversibly opaque so thatit may be used to control light transmission. In this paper the results of a study on polyaniline film as an electrochromicactive material is reported. Polyaniline looks yellow transparent in the reduced state and turns to green-blue at itsoxidized state. The electrochromic device considered in this paper was fabricated in planar configuration of ITO glass- polyaniline film - electrolyte - ITO glass which involved 1.0M H2SO4 solution. The measurement of the currentdensity yields voltamograms for several values of the rate of voltage change, while the optical characteristics weremeasured with ultraviolet-visible spectroscopy. To inspect the light control properties, the intensity of solar radiationpropagating through the device was derived. It is found that in its reduced state, the device transmits 70% of theincoming radiation, while in the oxidized state only 11% of the radiation is left. The result of recycling test indicatedthat film is stable over 5,000 cycles.Keywords: polyaniline film, electrochromic effect, smart window, solar radiation
SIFAT OPTIK PADA FABRIKASI POLIKRISTAL AgGaSe2
Get PDFOptic Properties on AgGaSe2 Polycristal Fabrication. Polycristal AgGaSe2, is compound (I-III-VI2) a semiconductoras basic material for thin film for solar cell. Polycristal was succesfully grown using Bridgmann Method, heated onsequential temperature treatment until 850°C and cooled down slowly until room temperature. Results observed were inthe form of ingot (bars) with more or less 3 cm length and 13 mm in diameter. By using X-Ray Fefraction, compositionobtained of each element (weight %) was Ag = 29,3996 %, Ga = 36,8123 % and Se = 30,29 % while using X-RayDifraction lattice parameter obtained/calculated a = 4,4112 Å, c = 8,8854 Å, and c/a = 2,01426.Keywords: Bridgmann Method, chalcopyrite, polycristal AgGaSe2, lattice parameter
3D MODELLING WITH LINEAR APPROACHES USING GEOMETRIC PRIMITIVES
Get PDFIn this paper, we study linear approaches for 3D model acquisition from non-calibrated images. First, the intrinsic andextrinsic camera calibration is taken into consideration. In particular, we study the use of a specific calibrationprimitive: the parallelepiped. Parallelepipeds are frequently present in man-made environments and naturally encode theaffine structure of the scene. Any information about their euclidean structure (angles or ratios of edge lengths), possiblycombined with information about camera parameters is useful to obtain the euclidean reconstruction. We propose anelegant formalism to incorporate such information, in which camera parameters are dual to parallelepiped parameters,i.e. any knowledge about one entity provides constraints on the parameters of the others. Consequently, an image aparallelepiped with known Euclidean structure allows to compute the intrinsic camera parameters, and reciprocally, acalibrated image of a parallelepiped allows to recover its euclidean shape (up to size). On the conceptual level, thisduality can be seen as an alternative way to understand camera calibration: usually, calibration is considered to beequivalent to localizing the absolute conic or quadric in an image, whereas here we show that other primitives, such ascanonic parallelepipeds, can be used as well. While the main contributions of this work concern the estimation ofcamera and parallelepiped parameters. The complete system allows both calibration and 3D model acquisition from asmall number of arbitrary images with a reasonable amount of user interaction.Keywords: parallelepiped, the affine structure, euclidean structure, 3D mode
PENGOLAHAN LIMBAH ORGANIK (FENOL) DAN LOGAM BERAT (Cr6+ ATAU Pt4+) SECARA SIMULTAN DENGAN FOTOKATALIS TiO2, ZnO-TiO2, DAN CdS-TiO2 1. Pendahuluan
Get PDFSimultaneous Treatment of Organic (Phenol) and Heavy Metal (Cr6+ or Pt4+) Wastes over TiO2, ZnO-TiO2 andCdS-TiO2 Photocatalysts. Treatment of heavy metal (Cr6+ and Pt4+) and organic (phenol) wastes has been studied usingthe relatively new method, i.e. simultaneous photocatalytic process over TiO2 photocatalysts in the batch photoreactor.Following the photocatalytic reduction of the heavy metal wastes, recovery of Cr and Pt was carried out by precipitationand leaching method, respectively. The experimental results show that in the simultaneous photocatalytic system, thereis a synergism effect between the photocatalytic reduction of heavy metal waste (Cr6+ or Pt4+) and the oxidation oforganic waste (phenol), so that increasing the conversion of each other. Dopant of ZnO with the optimum loading (0.5wt%) could slightly increase the performance of TiO2 photocatalyst in photocatalytic treatment of the wastes. WhereasCdS dopant with the optimum loading of 1 wt% could significantly enhance the performance of TiO2 photocatalyst insimultaneous Cr(VI) reduction and phenol oxidation with the highest conversion of ≥ 97 % and 93 %, respectively.Photocatalytic reduction of Pt(IV) under 0.5%ZnO-TiO2 and 1%CdS-TiO2 photocatalysts effectively occurred with ahigh conversion (> 99 %) in 2 hours irradiation of UV. The optimum precipitation condition of Cr(III) recovery wasachieved at pH = 9, with the efficiency of recovery was 91 %. Optimum temperature of leaching process in Pt recovery was 100 oC, with the efficiency of recovery was 86 %.Keywords: photocatalysis, TiO2, phenol degradation, recovery of Cr and P
HASIL TANGKAPAN DAN LAJU TANGKAP UNIT PERIKANAN PUKAT TARIK, TUGU DAN KELONG
Get PDFFishing Catch and Catch Rate Assesment of Mini Trawl, Trapnet and Setnet Fisheries. This paper purposed toassessment for fishing catch and catch rate of the dragged gear on shrimp, trapnet and setnet fisheries in Tarakan. Catchand effort data (number and species), fishing time of capture unit, were used in analysis qualitative fishing catch andcatch rate to describe catch compotition and catch rate from three unit capture fisheries in Tarakan. The result ofresearch showed that in the operation draged gear on shrimp have two main catch are nomei fish and shrimp. on thetheir two fishing season. Nomei fish as to be a main catch on the trapnet fisheries and pelagic fishes that estuary andcoastal of waters as to be a main catch on the setnet fisheries. Dragged gear on shrimp operation with nomei fish as amain catch have catch rate of value are 16.10 kg/hour and trapnet fisheries are 1.67 kg/hour. Catch rate of value fromsetnet fisheries are 5.39 kg/day and dragged gear on shrimp operation with shrimp as a main catch have a catch rate ofvalue 2.05 kg/hour.Keywords: fishing catch, catch rate, mini trawl, setnet, trapne
LIPID PRODUCTION FROM MICROALGAE AS A PROMISING CANDIDATE FOR BIODIESEL PRODUCTION
Get PDFRecently, several strains of microalgae have been studied as they contain high lipid content capable to be converted tobiodiesel. Fresh water microalgae Chlorella vulgaris studied in this research was one of the proof as it contained hightriacyl glyceride which made it a potential candidate for biodiesel production. Factors responsible for good growing ofmicroalgae such as CO2 and nitrogen concentration were investigated. It was found that total lipid content wasincreased after exposing to media with not enough nitrogen concentration. However, under this nitrogen depletionmedia, the growth rate was very slow leading to lower lipid productivity. The productivity could be increased byincreasing CO2 concentration. The lipid content was found to be affected by drying temperature during lipid extractionof algal biomass. Drying at very low temperature under vacuum gave the best result but drying at 60oC slightlydecreased the total lipid content.Keywords: biodiesel, lipid, microalgae, nitrogen concentration, productivit
PHASE UNWRAPPING CITRA InSAR MENGGUNAKAN PENDEKATAN MINIMISASI ENERGI LOKAL
Get PDFPhase Unwrapping InSAR Image Using Local Energy Minimization Approach. Reconstruction process of phasedata from its cover is called Phase Unwrapping (PU). Ideally, without any noise phrase, singularity, and aliasingproblems, the phase information can be unwrapped easily. However, in fact, the phase data actually always get noisedisturbance and discontinuity. The PU process becomes more complicated and needs a better PU algorithm to addressthe problems properly. In this research, the local PU algorithm is developed using minimization of close related firstorderpixels energy approach. In this method, the energy difference between four close related pixels is counted,followed by getting the probability value to obtain its total multiple ranges. Based on the research using synthesis ringimage and InSAR with coherence 0.8, the Peak Signal to Noise Ratio (PNSR) range will be 30.5373 dB in 20 itteration.Keywords: phase unwrapping, energy minimizatio
SPECTRAL RESPONSE SURFACES AND THE RINGING RESPONSE OF OFFSHORE STRUCTURES
Get PDFA method, called spectral response surface method, is proposed for the study of the ringing phenomenon of offshorestructures. Newman’s results for diffraction force on a column were reformulated in terms of the frequency componentsof the ocean surface and their Hilbert transforms. Using a first-order reliability method together with a dynamic modelfor the structural response, it is straightforward to calculate the ocean surface history most likely to generate an extremeringing response and the ringing response history.Keywords: ringing, spectral response surface, first-order reliability metho
PENGGUNAAN EKSTRAK ANTOSIANIN KOL MERAH SEBAGAI FOTOSENSITIZER PADA SEL SURYA TiO2 NANOKRISTAL TERSENSITISASI DYE
Get PDFThe use of Red Cabbage’s anthocyanine extract as a photosensitizer on a Dye-Sensitized Nanocrystalline TiO2Solar Cell. A solid-state dye-sensitized nanocrystalline TiO2 solar cell utilizing anthocyanin extract form red cabbageas photosensitizer was fabricated. The solar cell was formed in sandwich structure, which two electrodes sandwichingpolymer electrolyte containing a redox couple (I-/I3-). One of the electrodes, namely working electrode, TiO2 layer onTCO (transparent conducting oxide) coated glass substrate was sensitized with anthocyanin dye as electron donor in thesystem. Another electrode was a carbon sheet as a counter electrode. Gel electrolyte based on PEG (polyethyleneglycol) containing a redox couple (I-/I3-) used instead of liquid electrolyte in this photoelectrochemical cell. Twofabricated cells have an active area of 1 cm2 were soaked with anthocyanine dye for 1 hr and 24 hrs, respectively. Thecells were tested by irradiation with halogen lamp of 24 Watt with intensity 4 mW/cm2 at a distance 30 cm. The testingresults of the cells show an ideal I-V characteristic with output parameters: open circuit voltage (VOC) of 500 mV, shortcircuit current (ISC) of 5,6 μA and 7,2 μA for each cells, fill factor (FF) of 48% for both cells, energy conversion (η) of0.023 % and 0,055 % for the cells with 1 hr and 24 hrs dye soaked, respectively.Keywords: Dye-sensitized solar cell, TiO2 electrode, Natural dye, Anthocyanine, Polymer electrolyt