Jurnal ILMU DASAR
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Mechanical Properties and Biodegradability of Bamboo and Sengon Wood Thin Sheets Reinforced Poly Latic Acid (PLA) Biocomposites)
No full textDevelopment of biocomposite materials based on natural fibers and environmentally friendly resins to replace composite materials made from plastic and synthetic fibers give the consideration that the biocomposite materials are environmentally friendly materials. In this paper, we discuss the synthesis and characterization of biocomposite materials using a combination of thin sheets of bamboo reinforcement and resin sengon and poly lactic acid (PLA). As controls were also carried out the synthesis and characterization of biocomposite material with a thin layer of reinforcement only sengon bamboo and wood. Characterization of tensile strength and modulus of elasticity of the material is done by using the Tensile Test Machine ASTM D 638. In the mean time, biodegradability of materials are observed made by the method of burial for 1-4 weeks. Tensile test results show that the biocomposite material reinforced with a thin sheet bamboo has a tensile strength and modulus of elasticity greater than that of the other biocomposite materials produced in this study. Meanwhile, biocomposite materials with thin layers of wood sengon reinforced easily biodegradable (dG = 13.21 ± 0.59)%, compared to a biocomposite material with a thin layer of bamboo reinforcement (dG = 10.69 ± 0.79)%. From these results it can be concluded that the composite material with a thin layer of bamboo boosters are more likely to be applied to replace metallic materials.Keywords: Biocomposites, tensile strength, elastic modulus, biodegradability, bamboo and sengon wood thin layer
Purification and Characterization of Antibacterial Protein from Pheretima javanica
Get PDFThis research aimed to examine and isolate antibakterial protein from three species of earthworms has antibacterial potencies. The research was conducted in several stages, namely: extraction earthworm by using three kinds of solvents; antibacterial activity test of earthworm extract by agar diffusion method; purification of antibacterial protein by using DEAE chromatography, filtration column chromatography, and Native-PAGE. The results showed that three species of earthworms contained antibacterial protein. The activity of antibacterial protein extract of Pheretima javanica in MOPS buffer was highestand the inhibition zone diameter were10.0-14.0 mm. Compared to the other solven, the of MOPS buffer most precise for the solvent of protein. The extract of Pheretima javanica with MOPS solvent was fractionated by using DEAE chromatography (anion exchanger) and produced three peaks of protein group. Among the peaks, last peak that need 0.380 M NaCl to eluate performed antibacterial activity. Further fractionation of the protein by using gel filtration chromatography produced two peaks and one of the peak has antibacterial activity. Further purification that carried out by cutting the active fraction of second protein peak by using Native-PAGE produced seven bands. A single protein of the sixth band from lowest band showed antibacterial activity.Â
Design of Gas-Cooled Fast Reactor 600MWth with Natural Uranium As Fuel Circle Input
Get PDFThis article presents the conceptual design of gas-cooled fast reactor (helium), the small size of the long-lived 600 MWth. Early stages of the design is to determine the geometry of the terrace, the value of the volume fraction and the mass fraction of fuel, cladding and coolant structure to calculate the parameters of reactivity, burnup, power distribution and density changes nuclides U238 and Pu239. The calculation is done using SRAC-CITATION code. SRAC code with JENDL-3.2 Data nuclides produced macroscopic cross section values for the eight energy group. Multi-group numerical solution of diffusion equations for 2-D geometry terrace RZ performed by CITATION code. The study results showed that the scheme Modified CANDLE, thermal power output is 600 MWth, with a fuel cycle for 10 years. This reactor has the advantage of requiring only the input of natural uranium in the fuel cycle, without the need for enrichment processes that affect the economic value. Keywords : Reactor, natural uranium, modified candle, burnu
Constructing Fuzzy Time Series Model Using Combination of Table Lookup and Singular Value Decomposition Methods and Its Application to Forecasting Inflation Rate
Get PDFFuzzy time series is a dynamic process with linguistic values as its observations. Modelling fuzzy time series data developed by some researchers used discrete membership functions and table lookup method from training data. This paper presents a new method to modelling fuzzy time series data combining table lookup and singular value decomposition methods using continuous membership functions. Table lookup method is used to construct fuzzy relations from training data. Singular value decomposition of firing strength matrix and QR factorization are used to reduce fuzzy relations. Furthermore, this method is applied to forecast inflation rate in Indonesia based on six-factors one-order fuzzy time series. This result is compared with neural network method and the proposed method gets a higher forecasting accuracy rate than the neural network method
Antifeedant Activity from Leaves Extract of Aglaia ganggo Miq on Spodoptera litura
Get PDFThe different fraction extracts (viz methanol, dichlorometana, n-hexane, ethylacetate, and aceton) obtained from leaves of Aglaia ganggo Miq were investigated for antifeedant activity against Spodoptera litura. All extract fractions showed antifeedant activity with aceton fraction exhibited the highest antifeedant activity at 1 ppm concentration. Only hexane fraction showed a dose dependent concentration while the other fractions exhibited the opposite respond.Keywords : Antifeedant, Aglaia ganggo, extract, fractio
Antioxidant Activity Assay of Dragon Fruit Extract (Hylocereus undatus (Haw.) Britt. & Rose
Get PDFDragon fruit (Hylocereus undatus (Haw.) Britt. & Rose) familia Cactaceae has been cultivated for its beneficial properties on lowering both blood’s cholesterol and glucose level which were related with free radical-antioxidant mechanism. The fruits content antioxidants compound such as vitamin C, caroten, betacyanin pigments dan phenol; therefore it is necessary to determine its antioxidant activity. In this study, the antioxidant activity was performed on both methanolic and water extracts of dragon fruit (planted in Rembangan-Jember area) using diphenyl picryl hydrazil hydrate (DPPH) as stable free radical in spectrophotometric methods. The result showed that both methanolic and water extract exhibits DPPH free radical scavenger as an antioxidant activity with EC50 value sequentially 1.08 % and 2.98 %.Keywords : dragon fruit, Hylocereus undatus (Haw.) Britt. & Rose, free radical, DPPH, EC50
Solution Estimation of Logistic Growth Model with Ensemble Kalman Filter Method
Get PDFEnsemble Kalman Filter (EnKF) can be applied for linear or nonlinear models. This paper is aimed to estimate the logistic growth of population models using EnKF. The estimation will be compared with the analytical solution. We assume that we can find the analytical solution of the models. The models is in the specific form i.e comparison between the population growth rate and the amount of population is in the parabolic form. The good estimation will be attained by choosing 100 as size of ensembles in EnKF. The result of estimation really so closed to the analytical solution. Keywords : Analytical solution, EnKF, ensembl
Photodegradation Of Diazinon Pesticide In Suspension Of TiO2
Get PDFStudy on photodegradation of diazinon pesticide in suspension of TiO2 under ultra violet (UV) illumination was conducted. The aims of study are to determine the effective mass of titanium dioxide (TiO2), the effect of catalyst in initial concentration, the half time, the rate constant, and the rate of degradation reaction. Experimental photocatalytic reactor model was designed and constructed as suspension reactor. Determination of the effective mass of TiO2, the concentration of diazinon residu was performed by HPLC . The concentrations of illuminated diazinon solution were colected as various effective mass of TiO2 and expressed as the concentration vs the mass of TiO2. The mass of TiO2 in minimum diazinon concentration was a the effective mass. The concentration of illuminated diazinon and illumination time relationships was expressed in the graph as ln C/C0 = - k t and regarded as a pseudo first-order. The half time, the rate constant, and the degradation rate was analyzed from the graph. The results show that the photocatalytic degradation of pesticide diazinon by using TiO2 under UV illumination was run effectively in the mass of 12.5 mg for the diazinon concentration of 25 mg/l. The decreasing of initial concentration of diazinon is 90.4 % in 120 minutes. The half time, the rate constant, and the degradation rate are 36,869 minute, 0.0188 /minute, and 0,470 mg/l minute, respectively. Keywords : Kinetic, degradation, diazinon, TiO
Solution methods of neutron transport equation in nuclear reactors
Get PDFA few numerical methods that usually used to solve neutron transport equation in nuclear reactor are SN dan PN method, Monte Carlo, Collision Probability and Methods of Characteristics . First two methods have been developed using diffusion approach, and last three methods suitable are applicated for transport approximation. Those of three methods have important role in the desain of nuclear reactors. In addition to follow the development of advanced reactor designs, the three methods were chosen because they do not use diffusion approach these are more accurate methods, as well as less need considerable computer memory. Of all the existing methods, the CP method has several advantages among the others. Keywords : Neutron transport, SN, PN, CP, MOC, M
Influence of Nd Substitution for Ca on Formation of 2223 Phase in the Superconductors (Bi,Pb)-Sr-Ca-Cu-O System: (Bi1.4Pb0.6)Sr2(Ca2-xNdx)Cu3O10+δ
Get PDFThe influence of Nd substitutions for Ca on formation of 2223 phase in the superconductors (Bi,Pb)-Sr-Ca-Cu-O system : (Bi1.4Pb0.6)Sr2(Ca2-xNdx)Cu3O10+δ has been studied. Samples were made by solid state reaction methods, with sintering temperature at 860oC for 40 hours continuously in air atmosphere. From the XRD characterization it is revealed that the samples are poly crystals and the volume fraction of Bi-2223 phase is less than 45%. All of samples show Meissner effect weakly on 77 K, which is indicate that in the samples has formed few superconducting high-Tc phase. This result is in accords with of the resistivity as function of temperature measurement, show that the Tcon-set at 88 K - 107 K, which is range of the critical temperature (Tc) of the Bi-2212 phase and Bi-2223 phase.Â