Atom Indonesia (E-Journal)
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Diffraction Plane Dependence of Micro Residual Stresses in Uniaxially Extended Carbon Steels
Get PDFIn the stress measurement using X-ray or neutron diffraction, an elastic anisotropy as well as a plastic anisotropy of crystal must be carefully considered. In the X-ray and neutron diffraction stress measurement for polycrystalline materials, a particular {hkl} plane is used in measuring lattice strains. The dependence of an X-ray elastic constant on a diffraction plane is a typical example caused by an elastic anisotropy of the crystal. The yield strength and the work hardening rate of a single crystal depend on a crystallographic direction of the crystal. The difference in the yield strength and the work hardening rate relating to the crystallographic direction develops different residual stresses measured on each {hkl} diffraction after plastic deformation of a polycrystalline material. The present paper describes the result of the neutron stress measurement on uniaxially extended low and middle carbon steels. A tri-axial residual stress state developed in the extended specimens was measured on different kind of {hkl} diffraction plane. The measurement on the {110}, {200} and {211} diffraction showed that residual stresses increased with increasing the plastic elongation and the residual stresses on {110} were compressive, {200} were tensile and those on {211} were the middle of the former two planes. Received: 30 September 2010; Revised: 28 October 2010; Accepted: 1 November 201
Degradation of Standard Dyes and Textile Wastewater as a Pollutant Model Using Gamma Radiation
Get PDFA degradation and a decoloration of textile wastewater using ionizing radiation are already applied which some factors influence i.e. original wastewater, pH, pollutant concentration, solubility and variation of polutant. A dyes standard had been treated using ionizing radiation and the mechanism degradation will be discussed. The percentage of the dye degradation about 90-99% at doses of 2-10 kGy. The degradation of textile wastewater using gamma radiation is was carried out at doses of 25 kGy. The combination of irradiation and the addition of coagulant caused the decoloration and the degradation of the textile wastewater
Irradiation Effect of Argon Ion on Interfacial Structure Fe(2nm)/Si(tsi=0.5-2 nm) Multilayer thin Film
Get PDFInvestigation includes formation of interfacial structure of Fe(2nm)/Si(tSi= 0.5-2 nm) multilayer thin film and the behavior of antiferromagnetic coupling between Fe layers due to Argon ion irradiation was investigated. [Fe(2nm)/Si]30 multilayers (MLs) with a thickness of Si spacer 0.5 - 2 nanometer were prepared on n-type (100) Si substrate by the helicon plasma sputtering method. Irradiation were performed using 400keV Ar ion to investigate the behavior of magnetic properties of the Fe/Si MLs. The magnetization measurements of Fe/Si MLs after 400keV Ar ion irradiation show the degradation of antiferromagnetic behavior of Fe layers depend on the ion doses. The Magnetoresistance (MR) measurements using by Four Point Probe (FPP) method also confirm that MR ratio decrease after ion irradiation. X-ray diffraction (XRD) patterns indicate that the intensity of a satellite peak induced by a superlattice structure does not change within the range of ion dose. These results imply that the surface of interface structures after ion irradiation become rough although the layer structures are maintained. Therefore, it is considered that the MR properties of Fe/Si MLs also are due to the metallic superlattice structures such as Fe/Cr and Co/Cu MLs.Received: 2 April 2009; Revised: 2 September 2009; Accepted: 5 January 201
Sonolytic Oxidation of Tc(IV)O2nH2O Nanoparticles to Tc(VII)O4 in Aqueous Solution
Get PDFSonolysis of a hydrosol of TcO2nH2O was investigated in the Ar- or He- atmosphere. Colloidal TcO2nH2O nanoparticles were irradiated with a 200 kHz and 1.25 W/cm2 ultrasound. It was found that the TcO2nH2O colloids dispersed in an aqueous solution (under Ar or He atmosphere) was completely dissolved by ultrasonic irradiation (200 kHz, 200 W). The original brownish black color of the suspension slowly disappeared leaving behind a colorless solution. This change suggests that oxidation of Tc(IV) to Tc(VII) takes place. The oxidation was almost complete during 30 minutes sonication time under argon atmosphere for initial concentration of 6.0E-5 M. Addition of t-butyl alcohol, an effective radical scavenger which readily reacts with OH radicals, supressed the dissolution of TcO2nH2O colloids. This reaction indicates that TcO2nH2O molecules are oxidized by OH radicals produced in cavitation bubbles. Received: 20 November 2009; Revised:14 April 2010; Accepted: 18 April 201
Analysis of the Institutional Framework For Radioactive Waste Management in Indonesia
Get PDFThe analysis of the infrastructure for radioactive waste management in Indonesia has been studied using several parameters, i.e. policy, regulatory authorities and their regulations, implementing organizations and financial system. By considering the international trends and the Indonesian program to utilize nuclear power, the infrastructure of radioactive waste management needs to be improved. The Act No. 10/1997 on Nuclear Energy for the future beneficence will have to be amended to incorporate several missing key points on waste management, such as definition of radioactive waste, disposal of Low and Intermediate Level Waste (LILW), and classification of waste. Full involvement of some important stakeholders, especially the State Ministry of Environment, on the radioactive waste management infrastructure is required since some radioactive waste is generated from non nuclear waste. Assigning full authority to the State Ministry of Environment for regulating radioactive waste generated by non nuclear facilities may be more effective, whereas BAPETEN is still holding onto control over the waste generated from nuclear facilities. In the near future, several regulations on clearance level, classification of waste, NORM/TENORM, and financial system are expected to be set up for urgent need. By considering the high risk for handling of radioactivity, including for transportation and storage, the liability or assurance of the safety for such activities must be accounted for. Finally, establishment of financial system for long term waste management in Indonesia needs to be implemented to ensure that the radioactive waste will not be the burden on future generations.Received: 21 April 2009; Revised: 18 August 2009; Accepted: 25 August 200
Coupled–Channels Analyses For Heavy–Ion Fusion Reactions of 16O+92Zr,144,148Sm Systems
Get PDFWe study in detail the fusion reaction of 16O with 92Zr and 144,148Sm at sub-barrier energies with coupled-channels framework using the error function potential for the nuclear potential. In particular, we investigate the effects of multiphonon excitations in target nuclei on experimental fusion cross section and barrier distributions for these reactions. We show that the present coupled-channels calculations well account for the experimental data of the fusion cross section as well as the fusion barrier distributions. It is shown that the coupled-channels calculations taking into account the coupling up to double quadrupole phonon excitations in 92Zr well reproduce the experimental fusion cross section as well as fusion barrier distribution for 16O+92Zr. However, for 16O+144Sm, coupling to single quadrupole and octupole phonon states in 144Sm can well explain the experimental data. And the coupling up to triple quadrupole phonon states and double octupole phonon excitations in 144Sm are needed in order to reproduce the experimental data. Our study indicates the error function potential is adequate for analyses of the heavy-ion fusion reactions. Received: 20 November 2009; Revised: 17 April 2010; Accepted: 18 April 201
The Performance of Fine Resolution Neutron Powder Diffractometer at PTBIN-BATAN
Get PDFWe describe the performance of a fine resolution neutron powder diffractometer, DN3, which has been installed at the neutron guide (NG2) in the Neutron Guide Hall about 71 m away from the Multipurpose G. A. Siwabessy reactor core. DN3 has a multi-detector system which consists of 32 3He neutron detectors and soller-type collimation. The resolution curve of the instrument was found to have little variation over a wide angular region. The best resolution is Δ2θ (FWHM) of 0.23º and Δd / d of 5x10-3, where 2θ and d are scattering angle and d-spacing, respectively. The instrument provides sample environment of low temperatures using a cryostat having a temperature range of 10-300K. Several experimental results, interlaboratory comparison study and he next activities to improve the performance of DN3 equipment have also been discussed. Received: 15 October 2009; Revised: 12 April 2010; Accepted: 21 April 201
Development of Sorghum Tolerant to Acid Soil Using Induced Mutation with Gamma Irradiation
Get PDFWater scarcity still becomes a problem in some dryland agricultural areas in Indonesia. Development of dryland farming system may be focused on crops that are required less water such as sorghum. Sorghum is a cereal crop that is usually grown under hot and dry condition and it is ideal for Indonesia. Sorghum is a good source of food, animal feed and raw material for ethanol. Indonesia is currently looking for alternative renewable energy resources and sorghum is regarded as one of the promising source of bioethanol as bioenergy. Unfortunately, most agricultural land in western part of the country particularly in Sumatera and Kalimantan is dryland and dominated by acid soil. The main constraint of crop production in acid soil is deficiency and Al toxicity. Therefore, development of sorghum cultivation in dryland farming system requires a variety which is tolerant to such conditions. Sorghum breeding for acid soil tolerance had been conducted at PATIR-BATAN by using induced mutations with gamma irradiation. The breeding objective was to search for sorghum genotypes tolerant to acid soil condition and with regard to sorghum use for bioethanol production. A number of 66 breeding materials, including the mutants, had been screened for acid soil tolerance on land with soil pH of 4.2 and 39% Al saturation in Lampung Province. Ten sorghum genotypes had been identified as high yielding in the acid soil condition. The mutant lines GH-ZB-41-07, YT30-39-07, B-76 and B-92 had grain yield higher (4.5 t/ha) than the control plants (Durra, Mandau and Numbu). Sorghum mutants ZH30-29-07, ZH30-30-07 and ZH30-35-07 were promising for grain-base bioethanol production with ethanol yield exceeded 2,000 l/ha. Meanwhile, the sweet sorghum mutants ZH30-35-07, ZH30-30-07 and ZH30-29-07 had brix content of 11.59, 11.95 and 10.50%, respectively. These mutant lines are promising to be developed further in sorghum breeding since they are highly tolerant to acid soils. Received: 20 November 2009; Revised: 20 April 2010; Accepted: 21 April 201
Role of Radiation Processing in Production of Hydrogels For Medical Applications
Get PDFRecently, hydrophilic polymer gel (hydrogel) for application in medical fields has attracted much attention of researchers due to its unique properties which can resemble human living organs. Wound dressing, contact lenses and drug delivery system are among their applications in medical field. High energy radiation especially gamma ray and electron beam is often used for synthesis and modification of hydrogel. Through radiation crosslinking and or grafting process, hydrogel with specialty properties for specific application can be made. The advantage of radiation synthesized hydrogel over conventional methods is very pure products are obtained since the present of chemical initiators are not required; The preparation of sample does not require special sterile production rooms but still enables to obtain a sterile product; The irradiation process is easily controlled; Synthetis of new polymers and bulk or surface modification of commercial products can be accomplished with additional advantage of possibility of a concurrent sterilization. The future prospect of hydrogel seems to be in tissue engineering and diagnostic fields. Received: 27 February 2009; Reevised: 27 May 2009; Accepted: 16 June 200
Neutron Diffraction Study on the Magnetic Structure of Pr6Fe13Sn
Get PDFWe have successfully prepared a Pr6Fe13Sn sample by employing argon arc melting. The crystal structure of the sample has been examined by an x-ray diffraction. The x-ray pattern reveals that the sample crystallize in the tetragonal Nd6Fe13Si structure type with space group I4/mcm. Neutron diffraction at 150K performed on a powder sample shows a collinear antiferromagnetic ordering of the Fe and Pr sublattices with the wave vector (0, 0, 1) and an Ip type magnetic lattice with anti-centering translation. The main axis of antiferromagnetism is restricted to the (0 0 1) plane. The average refined Fe moments at 150 K is (2.0±0.4) µB whereas the Pr moments are (2.1±0.4) and (1.9±0.4) µB for the 8f and 16l sites, respectively. Received: 20 November 2009; Revised: 3 April 2010; Accepted: 20 April 201