Atom Indonesia (E-Journal)
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Determination of Informal Sector as Urban Pollution Source : Fume Characterization of Small-scale Manual Metal Arc Welding using Factor Analysis in Bandung City
Get PDFIn developing countries, the informal sector, particularly small-scale welding activities, are considered to be an important contributor to urban air pollution although studies in this sector are limited. This study aims to identify the composition of small-scale welding fume in order to further investigate the effects and set control strategies and urban pollution abatement policies. Breathing zone air samples were collected from 30 mild steel manual metal arc welders and 17 non-welders in Bandung City, West Java, Indonesia. The respirable particulates in air samples were analyzed using gravimetric method, and Instrumental Neutron Activation Analysis (INAA) was employed to identify characteristic of welding fume. It was found that respirable particulates concentration in welders (range : 315.6 and 3,735.93 µgm-3; average 1,545.436 µgm-3) were significantly higher than in non-welders (range : 41.84 and 1,688.03 µgm-3; average : 375.783 µgm-3). Welders’ breathing zones contain FeNaKMnAl CrTiClBrIZnSbVCoSc; while non-welders’ breathing zones contain CrFAlTiNaBrIMnClCoZnSc. Inter-species correlation analysis conducted using Statgraphic Ver. 4.0 shows that Fe (range : n.d. – 775.19 µgm-3; average: 0.1674 µgm-3), Co (range : n.d. – 0.51 µgm-3; average: 0.000082 µgm-3), Mn (range : 0.39 – 148.37 µgm-3; average: 0.0374 µgm-3), Na (range: 0.17 and 623.85 µgm-3; average: 0.0973 µgm-3) and K (range : n.d. – 301.15 µgm-3; average: 0.0535 µgm-3) were emitted from welding activity, and thus are considered as components of welding fume which contribute to urban air pollution. Although welding fume and the identified species in welding fume were still below permissible limit, small-scale welding activities have great potential in emitting higher fume concentration due to due to high variability of welding activities, such as welding frequency, materials being welded, and varied environmental conditions.Received: 5 December 2011; Revised: 17 April 2012; Accepted: 20 April 201
Theoretical and Practical Aspects of ‘Wasteless’ Nuclear Energy
Get PDFThe problem associated with the current NPP is the generation of nuclear waste and some elements in the waste have very long time of radioactivity. This paper reviews some concepts of nuclear energy generation with less nuclear waste. A concept of accelerator driven system (ADS) or energy amplifier (EA) was proposed by Carlo Rubbia, recipient of 1984 Nobel Prize in particle physics. The system is supposed to generate nuclear energy with radioactive waste of much less and shorter lifetime than those generated by present generation of nuclear power reactors. Less radioactive waste will also be generated by fusion reactions, either in hot fusion of high temperature plasma confined in a very strong magnetic field, or in cold fusion conceptually happens in muon-catalytic and lattice-trap fusions. A concept of neutronless nuclear reaction, hence activating no radioisotopes, to generate nuclear power was proposed. Present nuclear power reactors based on fission are also the source of very large number of electron neutrinos, which can be used to study neutrino oscillations
Development of Pyrochemical Reprocessing of the Spent Nuclear Fuel and Prospects of Closed Fuel Cycle
Get PDFMolten-Salt Reactor (MSR) is a design of an advanced reactor system from the GEN IV family working in thermal or epithermal neutron spectrum and using thorium or transuranium fuel in the form of molten fluorides. It is based on the experience with the development of the molten-salt reactor technology in the Oak-Ridge National Laboratory in the United States. The MSR fuel cycle with integrated reprocessing represents one of the potential ways both for significant decrease of total amount of radioactive wastes for final deposition and for utilization of nuclear energy for electricity and heat production as effectively as possible. There are two pyrochemical reprocessing techniques studied in NRI Rez plc which are considered to be applied both for reprocessing of already existing spent fuel and for preparation and „on-line“ reprocessing of MSR fuel: (i) the Fluoride Volatility Method (FVM), which performs chemical conversion of spent thermal oxide fuel components into fluorides and their consequent separation by means of their different volatility, thermal stability and chemical affinity to various sorbents; and (ii) electrochemical separation of the actinides (Ans) and fission products (FP), represented mainly by lanthanides (Lns), from each other by electrolytic deposition method on solid cathode in molten fluoride media
Design and Construction of the Control System for Batan Small Angle Neutron Scattering Spectrometer (SMARter)
Get PDFA 36 m Small Angle Neutron Scattering (SANS) Spectrometer (SMARTer) has been installed in Serpong, Indonesia in 1992. As time goes by, the original main computer was out of order and the instrument had not been operated since 2003. In order to activate the SMARTer, in the year 2005, a work on designing and constructing a new control system for SMARTer was carried out. The main component of this control system is a programmable peripheral I/O (IC PPI 8255) and was assembled as a plug-in board at an ISA slot of a personal computer. An IC PPI 8255 was programmed to control the mechanical movements of the instrument’s components: four neutron guide tubes, six pinholes collimator, a detector and a beam stopper. The test either with or without neutron beam has shown that this control system can be implemented for the mechanical movements of SMARTer. Error of moving the detector in the distance range of 1.5 m – 18 m is only 1 mm and the other movements have no error at all (precise)
Rolling and Annealing Effects on Microstructure and Hardness of Commercial 405 Stainless Steel
Get PDFThe "cold-rolling" experiments for several values of true strain namely 5 percent, 10 percent, and 15 percent respectively have been carried out on commercial SS-405 steel samples at 350oC; the as-rolled samples were cut into several pieces in size of 10 x 10 x 5 mm3, and some pieces were annealed to 550oC for 24 hours. All samples were then mounted and polished before etching in order to observe the grain boundaries. The microstructure observation on all samples was carried out by using optical microscope (MO), meanwhile X-ray diffraction technique was employed in order to support the identification of the existing phases and to verify changes with respect to crystal orientation; the hardness tests were carried out by using Vickers micro hardness tester. The microstructure observation supported by X-ray diffraction results shows that the phase grains of rolled sample tends to take the oblong-shape, accompanied by a preferred orientation predominantly inclined toward the (110) plane. The microhardness testing results show that there has been an increase in the hardness of the as-rolled samples; Mainly because of the nearly negligible thickness of the original sample (being only 5 mm in size), the 15 percent as-rolled samples exhibits only a slight reduction in hardness compared to the 10 percent as-rolled samples; The main cause of this effect is the movement of some dislocations infiltrating the surface resulting in the reduction of the inner-stress in the bulk of the samples. In the rolled-annealed samples there is a very significant reduction in hardness compared to the as-rolled samples. Here the main cause is the recrystallization process taking place during annealing, which tends to significantly reduce the dislocations
Irradiation for the Safety and Quality of Home Style Frozen Snacks
Get PDFThere are to market frozen prepared meals for microwaving or conventional way of preparation. Such meals. which offer convenience growing trends in Indonesia, and lesser time preparation are available in the developed countries, either chilled with limited shelf-life or frozen for long term sale in supermarkets. Irradiation at pasteurization doses has a potential role in improving the microbiological safety and shelf-life of chilled-prepared meals. Medium doses of gamma irradiation, 3-7 kGy, applied to spring rolls, rissole and croquette, in combination with frozen state during irradiation, followed by storage at 5 ± 2°C, have been conducted in order to ensure the safety and quality of the products during storage. The three different snacks. six pieces each. were vacuum packed in a laminate pouch of Poliester/Aluminum foil/LLDPE followed by fteezing over night at -20°C prior to irradiation at cryogenic condition. Irradiation at a dose of 7 kGy could relatively maintain the quality of the products during three months of storage 5 ± 2°C, based on different parameters, such as microbiological assessments, some chemical characteristics, and organoleptic analysis using five hedonic scales
Gene Mutation as Biomarker of Radiation Induced Cell Injury and Genomic Instability
Get PDFGene expression profiling and its mutation has become one of the most widely used approaches to identify genes and their functions in the context of identify and categorize genes to be used as radiation effect markers including cell and tissue sensitivities. Ionizing radiation produces genetic damage and changes in gene expression that may lead to cancer due to specific protein that controlling cell proliferation altered the function, its expression or both. P53 protein encoded by p53 gene plays an important role in protecting cell by inducing growth arrest and or cell suicide (apoptosis) after deoxyribonucleic acid (DNA) damage induced by mutagen such as ionizing radiation. The mutant and thereby dysfunctional of this gene was found in more than 50% of various human cancers, but it is as yet unclear how p53 mutations lead to neoplastic development. Wild-type p53 has been postulated to play a role in DNA repair, suggesting that expression of mutant forms of p53 might alter cellular resistance to the DNA damage caused by radiation. Moreover, p53 is thought to function as a cell cycle checkpoint after irradiation, also suggesting that mutant p53 might change the cellular proliferative response to radiation. p53 mutations affect the cellular response to DNA damage, either by increasing DNA repair processes or, possibly, by increasing cellular tolerance to DNA damage. The association of p53 mutations with increased radioresistance suggests that alterations in the p53 gene might lead to oncogenic transformation. Current attractive model of carcinogenesis also showed that p53 gene is the major target of radiation. The majority of p53 mutations found so far is single base pairchanges (point mutations), which result in amino acid substitutionsor truncated forms of the P53 protein, and are widely distributedthroughout the evolutionarily conserved regions of the gene. Examination of p53 mutations in human cancer also shows an association between particular carcinogens and characteristicpatterns of these mutations. Even amongcancers of the same organ, the mutational spectrum of the p53gene could present different patterns by histologic subtypeor risk factors and mutagen involve
Study of Sulphate Origin in Shallow Groundwater in the Vicinity of Bantar Gebang-Bekasi Landfill Using Sulphur-34 and Oxygen-18
Get PDFBantar Gebang-Bekasi landfill-West Java has caused a social impact due to the possibility of groundwater contamination. An investigation to trace sulphate origin in shallow groundwater in surrounding of Bantar Gebang -Bekasi landfill had been done. The methods were related to Rafter for extraction of CO2 and Robinson-Kusakabe for extraction of SO2 gas. Both gases were injected to mass spectrometer for measuring of δ 18O (SO42-) and δ 34S (SO42-). The results showed that a mixing of sulphate from leachate water to shallow groundwater had occurred. The more enriched value of δ 34S (SO42-) as much as 8.87 o/oo in leachate water compared to shallow groundwater having that value of 3.92o/oo to 6.66 o/oo might be caused by rapidly growth of sulphate reducing bacteria. The source of oxygen in sulphide oxidation dominantly came from atmosphere whereas percentage of H2O supplying oxygen was 0-25% for groundwater and 40% for leachate water. The extend of this value in leachate water might be caused by higher degree of bacteria, higher content of heavy metals and lower content of dissolved atmospheric oxygen
Study of Graft Copolymerization of Acrylic Acid Onto Nata De Coco and its Application as Microfiltration Membrane
Get PDFChemical and physical modifications of membrane can be carried out by radiation induced graft copolymerization. The aim of this research is to prepare graft copolymers of acrylic acid onto nata de coco (NDC-g-AAc) by radiation and to study the performance of grafted copolymer as microfiltration membrane. Using a total dose of 30 kGy, the highest degree of grafting obtained were 209% and 142% for r (weight ratio of monomers to nata de coco) equal to 61.3 and 35.7 respectively. The increasing degree of grafting resulted in decreasing flux due to high hydrogen bonding between grafted acrylic groups and water. It was found that the degree of swelling of NDC-g-AAc membrane with r = 35.7 was higher than that of r = 63.1. The changes of chemical structure of membrane were characterized by FTIR spectroscopy which showed a new band at 1720 cm-1 attributed to the carbonyl group of acrylic aci
Digital Correlation of First Order Space Time in a Fluctuating Medium
Get PDFThe study of fluctuating medium has been of great interest through the use of the correlation techniques A laser beam is known to form a coherent beam which can be made to propagate within the fluctuating medium. This will allow the study of the outgoing beam using digital correlation technique. Based on the power spectrum, the integral transformation of the correlation function, one can obtain for instance the radius and mass of the particles executing Brownian motion in the dispersed solution. To correlate the laser beam directly may not allow the detection of signals by electronic means. A method of digitizing the light signals by means of light beat heterodyne technique is therefore adopted. The temporal and special correlation functions can be measure