[en] The 5th conference on nuclear science and technology was held on 21-23 November, 1992 in Bangkok. This conference contain papers on non-power applications of nuclear technology in medicine, agriculture and industry. These application including irradiation of food for desinfestation; tram technologies used in diagnosis and therapy and radiation chemistry important to industrial processes. Some technologies which evolved from the development of the nuclear power industry are also discussed

[en] Lanthanum and neodymium are among the high quantity elements in mixed rare earth from monazite processing. The popular rare earth separation process is liquid-liquid extraction. This research was carried out to study lanthanum and neodymium distribution in two extractants, di(2-ethylhexyl) phosphoric acid and tributylphosphate. The experimental results show that neodymium distributes in both extractants better than lanthanum. The distribution of both elements are higher at low acidity than at high acidity. Quick and rough investigation by calculating the ratio of distribution coefficient of neodymium to lanthanum in each extractant indicated that La-nd separation efficiency of Di(2-ethylhexyl) phosphoric acid is higher than that of tributylphosphate

[en] Technetium-99m-DMSA locallized at high concentration in the renal cortex so it was excellent for imaging the renal parenchyma. The radiochemical purity was studied by two methods; 1) ITLC-SA developed with upper organic phase of n-butanol saturated with HCl 0.3 M (1:1) and 2) ITLC-SG developed with MEK, 5% glycine and 85% methanol respectively. The results were similar, the labelling yield of 99mTc-DMSA complex was maximum at 1 hour and maximum activity and volume were 150 mCi and 3 ml respectively. The stability of lyophillized kit was about 180 days

[en] Seeds of eight papaya varieties were irradiated with gamma radiation at doses of 0, 100, 150 and 200 Gray, then planted at Sisaket Horticultural Research Center. Plants with no symptom of mosaic disease and those with rarely to moderately mosaic disease symptom and good yield were selected and five fruits of them were collected. Seeds from them (M₂ seed) were planted and inoculated the seedlings with Papaya Ringspot Virus(PRV) that caused mosaic disease. Seedlings that showed no symptom were transplanted to the field. It was found that irradiated papaya variety Kokokandam showed some characters different from non-irradiated one. The irradiated plants were shorter in height and internode, smaller in bush and leaf size and better tolerant to mosaic disease. The characteristic of other varieties are being observed including yield and disease tolerance

[en] The relation between compositions and colors of gamma irradiated tourmaline was investigated. Quantitative analysis of various color of tourmaline by neutron activation technique showed that the average contents of color samples were 14.91, 1.13, 0.65 and 0.32 percent, for aluminium, sodium, manganese and iron, respectively. Zinc, cesium and tantalum were found as trace elements. Traces of rubidium and thorium were also detected in some samples. Colorless tourmaline contained only 10.07 percent of aluminium, but as high as 7.45 percent of sodium with small contents of most trace elements (below the average of color tourmaline). High content of iron was observed in green tourmaline while the pink one contained very less.It can be concluded that gamma radiation will intensify pink color in tourmaline which contains small amount of iron

[en] A procedure for preparation of 99mTc generator based on conversion to zirconium molybdate gel of 99Mo produced by neutron activation was reported. The gel was prepared from zirconium oxychloride solution pH 1.6, ammonium molybdate solution pH 3-5 and mole ratio of Zr:Mo 1:1 which had water content about 7-8%. Small generators containing 1-1.5 g of gel were eluted with average efficiencies of 77% and the activity peak in the first 3 ml of 10 ml of saline solution. The amount of Mo and Zr in eluates were below the acceptance limit. The gel generators of activity about 100 mCi were prepared and had the good performance in elutability and stability

[en] Cotyledons of half month and one month-old seedlings of tomato varieties Sida, SVRDC 4, Sidatip 2 and VF 137 irradiated with gamma rays at the dose of 10 Gy were cultured on most suitable medium found, MS supplemented with 0.01 mg/1 NAA and 2.0 mg/1 BAP. Sometimes calli and multiple shoots derived from normal seedlings were irradiated with gamma rays at the doses of 5 and 8 Gy, respectively. Plantlets from in vitro culture were screened in the greenhouse by soaking roots in bacterial suspension at transplanting time or by pouring bacterial suspension on injured roots at 2-3 wk. after transplant. The concentration of bacterial suspension was 10⁵-10⁷ cells/ml. Total of 2541 tomato plantlets were screened and only 11 plants survived. They were, 5 plants from non-irradiated Sida, 1 and 2 plants from 5 and 10 Gy Sida, respectively, 2 plants from 5 Gy Sidatip 2 and single plant from non-irradiated VF 137. Most of the surviving plants were susceptible to tomato yellow leaf curl virus and only fruits from one Sida plant irradiated with 10 Gy could be harvested. Plants from these seeds will be further selected

[en] The technical advantages of the 1220 Quantulus liquid scintillation spectrometer allowed us to measure radon-222 in water by using alpha/ beta pulse-shape analyser(PSA) and the integral counting method are easy, convenient and rapid to analyse precisely. It is suitable for the field work and large samples size. The lower detection level of radon is 0.011 Bq liter^-1. Radon is extracted from water in a toluene-base liquid scintillator. The radon analyses were done with ground water, tap water, surface water and reservoir water. Most of radon content in ground water were found to be in the range of 3 to 11 Bq liter^-1. Very low radon activities found in surface water and tap water. The high level of radon activities found in reservoir water, up to 65 Bq liter^-1

[en] The study on the growth of Rhizobium japonicum THA-7 in carriers: Peat Sludge, Filter press cake from sugar industry and the mixer compone nts of Sludge and Filter press cake. These carriers were sterilized by Gamm a radiation at 55 Kilograys. Then rhizobium suspension which grew to late log phase in Mannitol Yeast Extract broth were transfer to carriers. The initial rhizobial cells were 10⁷ cfu at 50 percent moisture content. The maximum growth (10⁹ cfu) was found after incubation at 30^oC for 17 days in all carriers. The rhizobial cells were stored in carriers at 4^o- 5^oC for 120 days. The amount of cells in all carriers were detected at 10⁸ cfu. Maximum survival rate was in the mixture of sludge and filter press cake at the ratio of 1 : 3. Therefore, It should be used as biological fertilizer better than other carriers

[en] The program package for 2-dimensional bumpup calculation for TRIGA reactor has been being developed. To verify this package, 2-group macroscopic cross sections at 1 MW for major components of the reactor core were generated. The calculations of excess reactivity and bumpup for core loading no. 1-9 were performed by using this package. Comparing the calculated excess reactivities to the measured values obtained from the log book, the result indicates that the calculations are in good agreement with the measurements