Atom Indonesia (E-Journal)
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Formulation of Oil-in-Water Cream from Mangosteen (Garcinia mangostana L.) Pericarp Extract Preserved by Gamma Irradiation
Get PDFThe aim of this researchwas to formulate mangosteen (Garcinia mangostana L.) pericarp extract into oil-in-water (O/W) cream which stable and durable. In order to improve the shelf life durability of the formula, the irradiation of formula using gamma rays from cobalt-60 was done. The concentrations of extract were varied to 1, 2 and 3% and were irradiated by gamma rays with doses of 5, 7.5 and 10 kGy. Physicochemical and microbiological properties of these formulas were carried outfor 90 days stored at 30 ± 2°C and 40 ± 2°C. It was found that both of physicochemical and microbiological properties of the formulas were changed by extract concentrations and after irradiation. The irradiated formulas with dose up to 7.5 kGy, which were stored at 30 ± 2°C and 40 ± 2°C, presented acceptable physicochemical and microbiological stability for at least 90 days. Analysis by TLC (Thin Layer Chromatography)-densitometry to study decomposition of G. mangostana pericarp extract cream formulas was carried out 24 h after preparation and 90 day after storage. The result of TLC-densitometry analysis showed that G. mangostana pericarp extract in the cream formulas did not develope significant decomposition after 90 days of storage. Decontamination dose for all formulas was found to be about 7.5 kGy. At this condition, the bacteria and mold-yeast have been killed, without reducing the antioxidant activity.Received: 24 November 2013; Revised: 20 December 2013; Accepted: 26 December 201
Design and Development of Hand and Foot Contamination Monitor
Get PDFA hand and foot contamination monitor is a health physics instrument to provide detection and measurement of beta-gamma contamination on the palm of each hand and on the bottom surface of both feet/shoes. There are four channels of detection for two hands and two feet. Four G-M detectors have been used in a single unit to cover the whole area of hand and feet. A regulated high voltage DC power supply (900 V) has been designed using the PIC12F675 microcontroller to operate the pancake Geiger-Müller detectors. The reading is displayed on a linearly scaled 0-100 Bq/cm2 analog panel meter. The monitor detects beta–gamma radiation emitted by radioactive materials, and if the detected value exceeds a preset level, the monitor sounds an alarm and displays a reading in the respective panel meter. Indicator lamps are used to show the status of contamination. The performance of the system has been tested by using pulse generator and by flat surface radioactive calibration sources. Electronic linearity, detection efficiency, response to the contamination, calibration factor and percentage of error has been measured. Test results were satisfactory and the present system can be used instead of similar imported instruments. Received: 21 May 2014; Revised: 21 August 2014; Accepted: 22 August 201
Spectroscopic Studies of Soft X-Ray Emission from Gadolinium Plasmas
Get PDFThe temporal behavior of gadolinium (Gd) laser-produced plasmas has been studied using a modified grazing incidence spectrometer which allows to capture the evolution of the plasma with spectral and temporal resolution of 0.1 nm and 1 ns, respectively. Experimental results indicate that the soft X-ray emission follows the temporal behavior of the laser pulse at high laser power density of Ф = 4.4×1012 W/cm2 in which the soft X-ray emission lasts for 7.5 ns (at FWHM) whereas at Ф = 5.4×1011 W/cm2 and Ф = 7.6×1010 W/cm2 the emission lasts for only 4 ns and 2.5 ns respectively,these are shorter than laser pulse duration due to lower electron temperatures achieved in the plasma generation. Lower Gd ion stages ranging from Gd11+ – Gd14+ are also found to contribute to the spectral emission over time.Received: 08 November 2013; Revised: 09 May 2014; Accepted: 09 May 2014
Modification of Biodegradable Polyesters Using Electron Beam
Get PDFPoly(4-Hydroxybutirat)p4hb, Poly(butylene succinate-co-adipate) PBSA and Poly(e-caprolactone) PCL were electron beam (EB)-irradiated. Poly(4-Hydroxybutirat) was irradiated without any polyfunctional monomers (PFM). While PBSA and PCL were irradiated in the presence of polyfunctional monomers such asTrimethallyl isocyanurate (TMAIC), Polyethyleneglycol dimethacrylate (2G, 4G), Trimethylolpropane trimethacrylate (TMPT) and Tetramethylolmethane tetraacrylate (A-TMMT) at ambient temperature. Aim of the study is to improve the properties of biodegradable polyester. It was pointed out that crosslinking yield of P4HB (6.39% gel)was formed at dose of 90 kGy irradiated in vacuum conditions. Radiation degradation promoted, when P4HB was irradiated in air. The optimum crosslinking yield of PCL and PBSA respectively, were formed in the presence of 1% TMAIC at dose of 50 kGy. The biodegradability of the crosslinked PBSA evaluated by soil burial test is slightly retarded by increasing crosslinking yields.Received: 20 November 2013; Revised: 27 December 2013; Accepted: 31 December 201
Synthesis of Sulochrin-125I and Its Binding Affinity as α-Glucosidase Inhibitor using Radioligand Binding Assay (RBA) Method
Get PDFMost of diabetes patients have type 2 diabetes mellitus or non insulin dependent diabetes mellitus. Treatment of type 2 diabetes mellitus can be conducted by inhibiting the α-glucosidase enzyme which converts carbohydrates into glucose. Sulochrin is one of the potential compounds which can inhibit the function of α-glucosidase enzyme. This study was carried out to obtain data of sulochrin binding with α-glucosidase enzyme as α-glucosidase inhibitor using Radioligand Binding Assay (RBA) method. The primary reagent required in RBA is the labeled radioactive ligand (radioligand). In this study, the radioligand was sulochrin-125I. Prior to the sulochrin-125I synthesis, sulochrin-I was synthesized. Sulochrin-I and sulochrin-125I were synthesized and their bindings were studied using RBA. The molecular formula of the synthesized Sulochrin-I is C17H15O7I and its molecular weight is 457.9940. The sulochrin-125I was synthesized from sulochrin-I by isotope exchange method. From RBA, the dissociation constant (Kd) and the maximum binding (Bmax) were found as 26.316 nM and 9.302 nM, respectively. The low Kd indicates that sulochrin is capable of binding to α-glucosidase.Received: 08 November 2013; Revised: 28 February 2014; Accepted: 28 March 201
Reliability Study of the AP1000 Passive Safety System by Fuzzy Approach
Get PDFThe Westinghouse AP1000 is a new design nuclear power plant which has implemented the concept of passive system. Even though a passive system may be more reliable than an active one, the possibility of the passive system to fail still exists. In line with this possibility, generic database have been used to study the reliability of the AP1000 passive safety system. However, since the used data are not specific to the AP1000, the results of the analysis will not show its real performance. This study proposes a fuzzy reliability approach to overcome this problem. The proposed fuzzy reliability approach utilizes the concept of failure possibility to qualitatively describe basic event likely occurences and membership functions of triangular fuzzy numbers to quantitatively represent qualitative failure possibilities. A case-based experiment on reliability study of the AP1000 passive safety system involved to mitigate a large break loss of collant accident is used to validate the feasibility of the proposed approach. By comparisons, probabilities of basic events generated by the proposed approach are very close to the ones which have been used by previous reliability studies. This can be observed from the small numbers of relative errors, i.e. between 0.004125 and 0.079635. These results confirm that the fuzzy reliability approach offers a more realistic technique to study the reliability of the AP1000 passive safety system without the need to engage to precise probability distributions of its components which are currently unavailable. Received: 08 November 2013; Revised: 28 May 2014; Accepted: 02 June 201
Flow Characterization of Vapor Phase of Geothermal Fluid in Pipe Using Isotope 85Kr and Residence Time Distribution Modeling
Get PDFMeasurement of vapor flow in geothermal pipe faces great challenges due to fast fluids flow in high-temperature and high-pressure environment. In present study the flow rate measurement has been performed to characterization the geothermal vapor flow in a pipe. The experiment was carried out in a pipe which is connected to a geothermal production well, KMJ-14. The pipe has a 10” outside diameter and contains dry vapor at a pressure of 8 kg/cm2 and a temperature of 170 oC. Krypton-85 gas isotope (85Kr) has been injected into the pipe. Three collimated radiation detectors positioned respectively at 127, 177 and 227m from injection point were used to obtain experimental data which represent radiotracer residence time distribution (RTD) in the pipe. The last detector at the position of 227 m did not respond, which might be due to problems in cable connections. Flow properties calculated using mean residence time (MRT) shows that the flow rate of the vapor in pipe is 10.98 m/s, much faster than fluid flow commonly found in various industrial process plants. Best fitting evaluated using dedicated software developed by IAEA expert obtained the Péclet number Pe as 223. This means that the flow of vapor of geothermal fluids in pipe is plug flow in character. The molecular diffusion coefficient is 0.45 m2/s, calculated from the axial dispersion model. Received: 21 November 2013; Revised: 16 May 2014; Accepted: 23 May 201
Analysis of 99Mo Production Capacity in Uranyl Nitrate Aqueous Homogeneous Reactor using ORIGEN and MCNP
Get PDF99mTc is a very useful radioisotope in medical diagnostic procedure. 99mTc is produced from 99Mo decay. Currently, most of 99Mo is produced by irradiating 235U in the nuclear reactor. 99Mo mostly results from the fission reaction of 235U targets with a fission yield about 6.1%. A small additional amount is created from 98Mo neutron activation. Actually 99Mo is also created in the reactor fuel, but usually we do not extract it. The fuel will become spent fuel which is a highly radioactive waste. 99Mo production system in the aqueous homogeneous reactor offers a better method, because all of the 99Mo can be extracted from the fuel solution. Fresh reactor fuel solution consists of uranyl nitrate dissolved in water. There is no separation of target and fuel in an aqueous homogeneous reactor where target and fuel become one liquid solution, and there is no spent fuel generated from this reactor. Simulation of the extraction process is performed while reactor in operation (without reactor shutdown). With an extraction flow rate of 3.6 L/h, after 43 hours of reactor operation the production of 99Mo is relatively constant at about 98.6 curie/hour./hour.Received: 11 January 2014; Revised: 18 February 2014; Accepted: 28 February 201
Electronic and Optical Properties of Aluminum Oxide Before and After Surface Reduction by Ar+ Bombardment
Get PDFThe electronic and optical properties of a-Al2O3 after induced by 3-keV Ar+ sputtering have been studied quantitatively by use of reflection electron energy loss spectroscopy (REELS) spectra. The band gap values of a-Al2O3 was determined from the onset values of the energy loss spectrum to the background level of REELS spectra as a function of time Ar+ bombardment. The bandgap changes from 8.4 eV before sputtering to 6.2 eV after 4 minutes of sputtering.The optical properties of α-Al2O3 thin films have been determined by comparing the experimental cross section obtained from reflection electron energy loss spectroscopy with the theoretical inelastic scattering cross section, deduced from the simulated energy loss function (ELF) by using QUEELS-ε(k)-REELS software. The peak assignments are based on ELF and compared with reported data on the electronic structure of α-Al2O3 obtained using different techniques. The results demonstrate that the electronic and optical properties before and after surface reduction will provide further understanding in the fundamental properties of α-Al2O3 which will be useful in the design, modeling and analysis of devices applications performance.Received: 18 November 2013; Revised:12 June 2014; Accepted: 25 June 2014
Radiometric Mapping for Naturally Occurring Radioactive Materials (NORM) Assessment in Mamuju, West Sulawesi
Get PDFMamuju has been known to have high radiation dose rate which is comes from NORM in rock and soil. Major concern is due to its location which is near inhabitant settlement area. Preliminary research has been done by environmental team which is limited to main access road only, while some remote area has left untouched. The purpose of the research is to delineate the location and distribution of thorium and uranium anomaly in Mamuju, and also to provide adequate information regarding the anomaly and high dose rate area to decision makers and stakeholders in neither local nor central government. Method applied is radiometric mapping using spectrometer RS-125 with NaI(Tl) detector in the area of interest Geological Formation of Adang Volcanic, which is more than 800 square km in size. The radiometric mapping method is widely used in uranium/thorium exploration, and now has been added with the measurement of radiation dose rate which is appropriate to environmental surveys. The mapping has been successfully delineated the area of NORM or the area with thorium and uranium anomaly. Thorium and uranium anomaly identified related with multi-geological-process resulting the increase of grade into several fold from its original state.Received: 08 November 2013; Revised: 20 February 2014; Accepted: 10 March 201