No abstract available

[en] This proceedings was organized by the ASEAN Food Handling Bureau in Collaboration with the Thai Atomic Energy Commission for Peace. Experts from ASEAN and overseas were invited to present a series of papers covering the state of the art of irradiation technology and the important issues relating to food irradiation

[en] The strippable paint, one of the adhesion method, is to decontaminate solid surface of materials or/and a large area. Two kinds of specimen planchet, SUS 304 stainless steel and polycarbonate plastic, contaminated with radioactive ¹³⁷Cs were studied under various conditions. It included surface bottom types, the flat and convex concentric circle type, normal condition at room temperature and overheat condition (∼80 degree celsius). This method used coating paints which contains some elements to have a reaction with radioactive materials selectively. ALARA-Decon clear, Rempack-X200 clear, JD-P5-Mrs.Coat and Pro-Blue-color guard were selected to use as the coating paints. The contaminated surface was coated by the strippable paint under the optimum time, followed by peeling the paint seal. The Rempack-X200 showed the best result, the highest decontamination efficiency which are about 99-100% for all conditions of specimens. The JD-P5 and ALARA-Decon showed good results, which are 98-99% decontamination efficiency for the normal condition set of specimens and about 94-97% for the overheat set of specimens. They can decontaminate polycarbonate specimens better than stainless steel specimens. The Pro-Blue-color guard showed the lowest decontamination efficiency of which 60% for polycarbonate specimens at normal condition and 40%, 30% for stainless steel specimens at normal and overheat conditions respectively. There was no effects of surface bottom types significantly

[en] Gamma rays have high penetration power and its attenuation depends upon the thickness and the attenuation coefficient of the shield, so it is necessary to use the high density shield to attenuate the gamma rays. Heavy concrete is considered to be used for high radiation laboratory and the testing of the shielding ability and compressibility of various types of heavy concrete composed of baryte, hematite, ilmenite and galena is carried out. The results of this study show that baryte-ilmenite concrete is the most suitable for high radiation laboratory in Thailand

[en] The purpose of this experiment was to extract and purify the zirconium from zircon. The effects of time of extraction and stripping of zirconium, concentration of feed solution, concentration of hydrochloric acid in stripping process, equilibrium curve of extraction of zirconium and hafnium and equilibrium curve of stripping zirconium or scrubbing hafnium were studied from standard zirconium and hafnium. The results, subsequently were applied to the extraction procedures for zirconium from zircon. Minus 100 mesh zircon was fused with sodium hydroxide in the ratio of 1 : 6 at 700 degree C for l hour. After fusion the zirconate was leached with water and dissolved in hot concentrated hydrochloric acid. Zirconyl chloride octahydrate crystallized out when the solution was cooled. An agueons solution of zirconyl chloride was used as the feed to the hexone - thiocyanate solvent extraction process. This was prepared by dissolving zirconyl chloride octahydrate crystal in waster. This zirconium feed solution in 1 M HCl and 1 M N H₄CNS was extracted with 2.7 m N H₄CNS in hexone and then stripped with 3.6 M HCl the aqueous phase was got rid of thiocyanate ion by extracting with pure hexone, then the zirconium in aqueous phase was precipitated with sulfuric acid and ammonium hydroxide at pH 1.8 - 2.0 and zirconium oxide was obtained by ignition at 700 degree C. The process could be modified to improve the purity of zirconium by using cation exchange resin to get rid of thiocyanate ion after solvent extraction process

No abstract available

[en] We stress the usefulness of the work reservoir in the formalism of thermodynamics, in particular in the context of the first law. To elucidate its usefulness, the formalism is then applied to the Joule expansion and other peculiar and instructive experimental situations, clarifying the concepts of configuration and dissipative work. The ideas and discussions presented in this study are primarily intended for undergraduate students, but they might also be useful to graduate students, researchers and teachers.

[en] To determine the efficiency of gamma irradiator, Model JS-8900, IR-155, 50-kg commercial packages of green mungbean (Phaseolus aureus) were used. The optimum product throughput was 5,400 kg in 1 h 11.91 min. To improve product loading efficiency, 1-kg packages of green mung-bean were used and the optimum product throughput was 8,640 kg in 1 h 47.4 min. Green mungbean irradiated at 0, 0.5, 0.9 and 1.0 kGy were used for sensory acceptability evaluation. The panel accepted the color, taste and texture of steamed-green mungbean, regardless of radiation dose and accepted the odor of nonirradiated steamed-green mungbean. For raw-green mungbean, the panel accepted the color and odor of raw-green mungbean irradiated at 0, 0.5 and 1.0 kGy

[en] An on-line nuclear investigation technique called 'Gamma Scanning' using a 20 mCi Co-60 radioactive sealed source and a 2 inches NaI(Tl) detector in coupled with a rate meter was applied to evaluate the performances of the oil distillation columns in the oil refineries in Thailand. The radioactive source and the detector were moved vertically along side of the columns. Based on the gamma ray absorption behaviour of the inside medium, the detected gamma intensity was plotted v.s. the distance resulting the 'density profiles' of the columns. Consequently, the columns'performances and problems in the operation such as the location of liquid flooding on trays caused by blockage in liquid down comers could then be clearly identified. The technique was well applicable and very magnificent in giving adequate data confirming the process condition for the consequently problem solving and process optimization schedule

[en] Seven brands of shrimp paste (Kapi) sold in supermarkets were investigated for microbiological quality and quantity of salt. The effect of gamma radiation at dose 1 to 6 kGy on microbiological quality and on sensory quality of shrimp paste were also evaluated. Total viable bacterial counts of surveyed samples ranged from 1.20 x 10⁴ to 4.00 x 10⁵ colony forming unit (cfu) per gram and no detectable number of Enterobacteriaceae, coliforms, Faecal coliforms, Escherichia coil, Salmonella, Vibrio parahaemolyticus and Staphylococcus aureus was found. The most probable number (MPN) per gram of Clostridium perfringens is ranged from 9 to 240. Percentage of salt in surveyed shrimp pastes was rather high (ranged from 19.08 to 25.08). Radiation with 4 kGy resulted in 2 log cycles reduction of total viable bacterial counts and 2-4 log cycles reduction of halophilic bacteria, but no decrease in the most probable number per gram of CI. perfringens. A dose of 6 kGy gamma radiation was adequate for decreasing the MPN per gram of C. perfringens. No significant change in sensory scores for odour and flavor was observed in irradiated shrimp paste. Only in irradiated at dose of 6 kGy was the significant change in colour observed