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Effectiveness of Gamma Irradiation for Decontamination of Microbes on Tea Parasite Herb Scurrula atropurpurea (Bl.) Dans
Get PDFThe purpose of this study was to find the minimum and maximum dose of gamma irradiation on dried tea parasite herb that can reduce the number of microbes without reducing the inhibitory activity against leukemia L1210 cells. Samples of tea parasite herbs were irradiated by gamma rays with doses of 0, 5, 7.5, 10, 15 and 20 kGy. The microbial contamination, cytotoxic activities and the chromatogram profiles of irradiated and unirradiated samples were observed. The results revealed that the bacteria contaminants of 7.57 x 109 cfu/g were eliminated after irradiation of the samples with dose of 7.5 kGy, meanwhile the mold-yeast contaminants of 5.68 x 108 cfu/g were eliminated after irradiation of the samples with dose of 5 kGy. Ethyl acetate extracts of irradiated samples until the dose of 10 kGy were still able to maintain its cytotoxic activity against L1210 leukemia cells proliferation with IC50 values of 30 µg/ml. Fractionation of ethyl acetate extracts of each sample by open column chromatograph was obtained four fractions from each extract. Among the fractions, fraction 2 was the most active fraction which had a potent as anticancer agent. Cytotoxic activities assay of fraction 2’s showed that this fractions significantly decreased after irradiation of samples with doses up to 10 kGy. The thin layer chromatogram profiles of fraction 2 from irradiated and unirradiated samples showed that spot 2 and 3 gradually tended to fade. It is suggested that 7.5 and 10 kGy were the minimum and maximum irradiation dose for bacterial and mold/yeast decontamination with the initial contamination of 7.57 x 109 cfu/g and 5.68 x 108 cfu/g respectively. At this condition, the bacteria and mold/yeast have been killed, whereas the cytotoxic activities of active components (ethyl acetate extract and fraction 2) in tea parasite herbs decreased, but the decrease was not significant and did not remove these cytotoxic activities.Received: 20 November 2010; Revised: 07 September 2011; Accepted: 19 September 201
The Effects of Gamma Irradiation on the Growth and Propagation of In-Vitro Chrysanthemum Shoot Explants (cv. Yellow Puma)
Get PDFThe study on the effect of gamma irradiation on in-vitro shoot growth of chrysanthemum cv. Yellow Puma has been carried out. The aim of the study was to observe genetic variability of shoot growth caused by gamma irradiation. Shoot explants with four leaves were irradiated by gamma with dose of 10, 15 and 20 Gy with 3 replications at each of dose. The irradiated shoot explants were then transferred into fresh MS solid medium and placed in a growth room. Observation was performed on number of leaves and branches on M1V0 generation, while plantlets height and number of branches were observed a M1V1 generation. Number of survival plantlets and multiplication rate on three subsequent subcultures were observed as well. Results showed that gamma rays with dose of 20 Gy inhibited growth of leaves as much as 50% compared to control (shoots without irradiation), and branches 73.7% in three weeks. Observation on multiplication rate at M1V1 generation showed that gamma irradiation with dose of 10 Gy promoted multiplication rate as much as 10% higher than control. It can be concluded that in vitro mutagenesis using gamma iradiation with dose of 10 to 15 Gy can be used for inducing genetic variability of chrysanthemum cv. Yellow Puma. Received: 18 December 2008; Revised: 10 August 2010; Accepted: 30 August 201
Fuzzy Logic Application in Boron and Cadmium Analysis in U3O8 use of Emission Spectrograph Method
Get PDFBoron and cadmium in U3O8 have been analyzed with emission spectrograph. Three inputs of emission spectrograph, current (A), exposure time (second) and gap between electrodes (mm) were varied. Two outputs, boron and cadmium lines intensities respectively were selected and measured. Thirteen experiments have been carried out and data found were calculated by fuzzy logic Mamdani-type. Three and five memberships functions of straight-line (Triangular, Trapezoidal), Generalized-bell and Gaussian curve were used to analyze the found data. The result found that five memberships functions had less error percentage range than three memberships functions of straight-line (Triangular, Trapezoidal), Generalized-bell and Gaussian curve. The error percentage range of cadmium analysis was wider than boron analysis with this method. Analysis of cadmium in U3O8 with this method needs much exposure time compare to analysis of boron. Received: 28 December 2009; Revised: 29 November 2010; Accepted: 8 February 201
Pressure Dependence of Crystal Structure and Ionic Conductivity on Composite Glass (AgI)0.7(AgPO3)0.3
Get PDFThe superionic composite glass, (AgI)0.7(AgPO3)0.3 has been succesfully synthesized by melt quenching method. The crystall structure of coin type composite glass at various pressure of 100, 300 and 700 kg/cm2 have been measured by using an X-ray Difractometer at PTBIN-BATAN. The X-ray difraction pattern shows some Bragg peaks correspond to the crystaline γ-AgI. The increasing of pressure result the peaks become broaden and shift to the lower angle. This indicates that the crystal size is decreasing and the microstrain is increasing. Three strong peaks at (111), (220) and (311) have been analyzed by using a Gaussian Fitting. Based on calculation, crystal size (D) of (AgI)0.7(AgPO3)0.3 at pressures of 100, 300 and 700 kg/cm2 are 1114 Å, 13165 Å and 7240 Å respectively, while microstrain values (η) are 4 x 10-3 (1), 7.5 x 10-3 (4) and 8 x 10-3 (4). The composite glass (AgI)0.7(AgPO3)0.3 crystal structures at pressures of 100, 300 and 700 kg/cm2 have been analyzed by using a Rietveld method. The refinement results show that the peaks correspond to γ-AgI phase with a symmetry space group F-4 3 m No. 216, FCC, with the lattice constant namely 6.518(3), 6.508(3) and 6.506Ǻ(2) at a pressure of 100, 300 and 700 kg/cm2 respectively. The increasing of microstrain (η), and crystal size (D) and the decreasing of lattice constant (a) will increase the ionic mobility, thus increasing the ionic conductivity. The function of pressure on melt γ-AgI phase into glass matrix AgPO3 decreases the lattice constant and the crystal size, cause the increasing of microstrain broadening and ionic conductivit
Measurement of P Contribution From Several P Sources by Using 32P Method
Get PDFP-fertilizer other than chemical fertilizers has been used extensively in agriculture. However, the extent to which P-fertilizer contributes to the growth of plants has only been discussed a few, meanwhile the information will be very helpful to the use of P-fertilizer efficiently. The 32P method was used to distinguish P contribution from several sources, i.e soil, chemical fertilizer (Sp) and manure/organic fertilizer (Pk). The isotope carrier free solution of KH232PO4, which is contained of 98% 32P, was applied to the soil and thus making it as the only source of labeled-P. Radioactivity counting of soil samples will lead to the measurement of P-contribution from several sources of P given. The experiment result showed that most of the P taken up by the plants was from soil. Thus, the P from Sp (P-Sp) and Pk (P-Pk) became un-significantly support the plant growth expressed in lesser dry weight of straw, grain and plants compared to those who taken its P from soil. Although soil contributed most of its available P to straw and grain of lowland rice, but Sp and Pk still contributed P to both plant parts. It was obtained that in straw 64 – 82% P was derived from soil; 12 – 21% P was derived from Pk; and 18 – 29% P was derived from Sp. For grain 49 – 89% P was derived from soil; 11 – 15% P was derived from Pk; and19 – 45% P was derived from Sp. Received: 20 November 2009; Revised: 09 August 2010; Accepted: 23 August 201
The Semi-Quantitative Study of Magnetization Process on Milling and Reannealing of Barium Hexaferrite (BaO.6Fe2O3)
Get PDFBarium hexaferrite (BaO.6Fe2O3) is as a hard magnetic material with good chemical stability which has been intensively used as permanent magnet components. Many works have been done in order to improve their magnetic properties either through chemical process or powders metallurgy technique. In this work, commercial BaO.6Fe2O3 was milled using high-energy milling machine for 10, 20 and 30 hours and followed by reannealing for 3 hours at 1000⁰C in air. X-ray diffraction pattern indicate no phase decomposition occurred caused the mill processing, annealing of milled powders recovered the crystal system and promoted crystallite growth. The magnetic hysteresis curve measured by vibrating sample magnetometer (VSM) shows the coercivity of annealed BaO.6Fe2O3 increases to two times higher than the original one. By using Jiles-Atherton model, all the hysteresis parameters Ms, k, α, a and c, have been determined adopted to the Genetic Algorithm (GA). The analyzed hysteretic parameters obtained from this work is congruent to the change of magnetic properties of as-milled and annealed powders of barium hexaferrite.Received: 16 February 2009; Revised: 1 September 2009; Accepted: 23 November 200
Graft Copolymerization of Methyl Methacrylate Monomer onto Starch and Natural Rubber Latex Initiated by Gamma Irradiation
Get PDFTo obtain the degradable plastic, the graft copolymerization of methyl methacrylate onto starch and natural rubber latex was conducted by a simultaneous irradiation technique. Gamma-ray from cobalt-60 source was used as the initiator. The grafted copolymer of starch-polymethyl methacrylate and the grafted copolymer of natural rubber-polymethyl methacrylate were mixed in the blender, and dried it in the oven. The dried grafted copolymer mixture was then molded using hydraulic press machine. The effect of irradiation dose, composition of the grafted copolymer mixture, film forming condition and recycle effect was evaluated. The parameters observed were tensile strength, gel fraction and soil burial degradability of grafted copolymer mixture. It was found that the tensile strength of grafted copolymer mixture increased by γ-ray irradiation. Increasing of the grafted copolymer of natural rubber-polymethyl methacrylate content, the gel fraction and tensile strength of the grafted copolymer mixture increased. The tensile strength of the grafted copolymer mixture was increased from 18 MPa to 23 MPa after recycled (film forming reprocessed) 3 times. The grafted copolymer mixture was degraded completely after soil buried for 6 months. Received: 20 July 2010; Revised: 04 February 2011; Accepted: 10 March 201
Monte-Carlo Simulation of -ray and Fast Neutron Radiolysis of Liquid Water and 0.4 M H2SO4 Solutions at Temperatures up to 325oC
Get PDFMonte-Carlo simulations were used to study the radiolysis of liquid water at 25-325oC when subjected to low linear energy transfer (LET) of 60Co γ-ray radiation and fast neutrons of 2 and 0.8 MeV. The energy deposited in the early stage of 60Co γ-ray irradiation was approximated by considering short segments (~150 μm) of 300 MeV proton tracks, corresponding to an average LET of ~0.3 keV/μm. In case of 2 MeV fast neutrons, the energy deposited was considered by using short segments (~5 μm) of energy at 1.264, 0.465, 0.171, 0.063 and 0.24 MeV. 0.8 MeV fast neutrons were approximated by 0.505, 0.186, 0.069 and 0.025 MeV protons. The effect of 0.4 M H2SO4 solution on radiolysis was also studied by this method for both 60Co γ-rays and 0.8 MeV fast neutrons. The simulated results at the time of 10-7s after irradiation were obtained and compared with the available experimental results published by other researchers to be in excellent agreement with them over the entire temperature ranges and radiation sources studied. Except for g(H2) that increase with temperature rises, the general behaviors of higher radical products and lower molecular products at higher temperatures were obtained. The LET effect is also validated by this study, showing that the increase in LET would yield higher molecular and lower radical products. Studies on 0.4 M H2SO4 solutions also show good agreement between the computed and experimental data for γ-ray irrradiation: the presence of 0.4 M H+, except for g(H2) that gives lower value at 25oC and higher value at 325oC, gives the higher values for radicals and g(H2O2) at 25oC and lower values at 325oC, compared with that for neutral water. The computed data show good agreement with the experimental data for 0.4 M H2SO4 solutions induced by 0.8 MeV fast neutrons, except for g(H2) and g(H●) that gives good agreement up to 50oC, then the opposite tendencies with the further temperature rises. However, the simulated fast neutron radiolysis on acidic demonstrates similar tendencies on temperature dependence with that for simulated 60Co γ-radiolysis, but in different magnitude. For better understanding, more experimental data for fast neutrons are needed, especially under the acidic conditions. Received: 20 November 2009; Revised: 06 April 2011; Accepted: 12 April 201
Simulation of Ion Source’s Control System on Cyclotron Using Programmable System on Chip (PSoC)
Get PDFCyclotron is an ion accelerator machine with spiral beam path. Ion source system is one of the main systems which its function is to produce ions that will be accelerated. In order to obtain maximum ion current, the ion source must be equipped with a control system that control mechanical system that will adjust the position of the ion source. The mechanical system able to make adjustment in three different axis, that is x, y and z axis. The mechanical system consists of a stepper motor and a set of gears. The control system using Programmable System on Chip (PSoC) utilizes its user module from the Random Sequence group, that is 8-bit Pseudo Random Sequence Generator (PRS8).For x and y axis, if the stepper motor rotate one rotation that means the support will be pushed or pulled 2.5 mm. While for z axis if the stepper motor rotate one rotation that means the support will be pushed or pulled 0.83 mm. The largest deviation of the stepper motor is 2° with error percentage is 1.09%. The mean value of step of the stepper motor is 2.03 step per second.Received: 20 November 2010; Revised: 07 October 2011; Accepted: 11 October 201
Monitoring Low-Cycle Fatigue Material-Degradation by Ultrasonic Methods
Get PDFAny system consisting of structural material often undergoes fatigue, which is caused by dynamic load cycle. As a structural system, nuclear power plant is very likely to have low-cycle fatigue at many of its components. Taking into account the importance of monitoring low-cycle fatigue on structural components to prevent them from getting failure, the authors have conducted a work to monitor material degradation caused by low-cycle fatigue by using ultrasonic method. An alloy of Cu-40Zn was used as a test specimen. Ultrasonic water immersion procedure was employed in this ultrasonic test. The probe used is a focusing type and has frequency as high as 15 MHz. The specimen area tested is in the middle part divided into 14 points × 23 points. The results, which were frequency spectrums, were analyzed using two parameters: frequency spectrum peak intensity and attenuation function gradient. The analysis indicates that peak intensity increases at the beginning of load cycle and then decreases. Meanwhile, gradient of attenuation function is lower at the beginning of fatigue process, and then consistently gets higher. It concludes that low-fatigue material degradation can be monitored by using ultrasonic method.Received: 20 November 2009; Revised: 31 August 2010; Accepted: 31 August 201