[en] Several studies have indicated that consumer goods, air pollution, and by-products, residues, and waste products of natural resources exploitation contain uranium and thorium. In this research, the enhancement of these two metals resulted from the extraction process of Bangka tin slag. To deal with the enhancement of uranium and thorium, Bangka tin slag (BTS) was dissolved in hydrofluoric acid (HF), hydrochloric acid (HCl), and sodium hydroxide (NaOH). The result shows that Bangka tin slag has high contents of uranium, 3404 ppm, and thorium, 25 850 ppm, which were achieved through the dissolution of BTS-roasting-quenching-sieving (BTS-RQS) residues in HF 8 %, HCl 6 M, and NaOH 10 M. (author)

[en] Dose measurements of fast neutron and gamma radiation in the STIF (Standard Triga Irradiation Facility) located in the thermal column of the Bandung Triga Mark 2 reactor were carried out. The average dose rate for fast neutrons, variability of the irradiation capsule, amounted contaminating gamma doses, the biologically effective gamma dose, and the conversion factor were discussed. The fast neutron fluency causing a D₅₀ in primary leaves of barley was also determined, and the data were discussed. (SMN)

[en] Finite range central force of Yukawa shape with exchange terms have been used to calculate the energy levels of ²¹⁰Pb and ²¹⁰Po nuclei. Shell model wave functions with harmonic oscillator radial parts were employed for the calculations of the energy matrix elements. Comparisons between theoretical calculations and the experimental data are presented. Forces with fitted parameters reveal that the triplet odd parts are attractive in contrast to Rosenfeld forces which are repulsive. (author)

[en] A combined treatment of precooking in 10% brine containing various levels of K-sorbate and irradiation on chub mackerel (Restrelliger neglectus) has been studied. The effect of irradiation doses for extending the storage life of precooked samples held at ambient temperatures was described. Total bacterial count, total volatile base nitrogen, volatile reducing substances and mould growth were used as objective indices of quality in comparison with sensory evaluation of the product. The shelf life of the treated samples irradiated at 0,200, and 400 krad were found to be 2,5, 4 and more than 5 weeks respectively. No significant effect of the K-sorbate treatment was found on the odour, colour, flavour, and appearance of the precooked fish. (author)

[en] The influence of fertilizer placed at different soil-depths on the root and shoot growth of Pelita 1/1, one of many rice varieties used in Indonesia, was observed. In this experiment, the treatments were fertilizer (N, P, and K) placements at: 2.5, 7.5, 12.5, and 17.5 cm beneath the soil surface, and times of harvest at: 45, 52, and 59 days after seed germination. The parameter for root growth was the percentage of roots in the soil depths at: 0-5, 5-10, and 15-20 cm, respectively, while for shoot growth the parameters were: the fresh and dry weights of the shoots, number of leaves, number of tillers, and plant heights. The data obtained from this experiment indicated that highest root growth took place in the 0-5 cm soil depth, and this conccurently caused highest shoot yield. On the other hand the lowest shoot yield was resulted by the 17.5 cm deep placement of the fertilizer. With increasing age the plants developed higher root growth in the lower soil depth (10-15 and 15-20 cm) and placement of fertilizers at the sites showed a marked effect on root growth. The plant used in this experiment were grown in cylindrical plant containers made from PVC and placed in the green house. (author)

[en] An experiment has been done to determine the effect of irradiation and reduction of moisture content on the keeping quality of commercial spices, i.e. nutmeg (Myristica fragrans), black and white pepper (Piper ningrum). The results showed that a dose of 5 kGy could reduce the microbial load of spices as much as 2-4 log cycles for the total plate count and 1-3 log cycles for the total mould and yeast counts. The microbial reduction due to the irradiation treatment was found to be lower in more humid products. Prolonged storage enhanced the microbial reduction. (author)

[en] The earliest toxin production by three proteolytic strains of Cl. botulinum type B was determined in irradiated and unirradiated raw fish (Rastrelliger sp., Euthynnus sp., and Scomberomorus sp.) under the storage temperatures of 20, 10, and 5degC. The estimation of maximum storage life was evaluated by an untrained panel on uninoculated fish samples and in parellel the total bacterial counts were also determined. Percentage data of the toxic samples were analyzed according to a fully randomized design involving factorial treatments. In unirradiated samples with inoculum levels of 10²-10⁶ spores per gram and stored at 20degC, the earliest toxin production was detected after the samples were spoiled. While in irradiated samples toxin were detected before the end of the storage life or after the samples were spoiled, depending on the levels of inoculum. In general, both in unirradiated and irradiated samples inoculated with 10²-10⁶ spores per gram and stored at 10degC, the earlieast toxin production was detected after the samples were spoiled. While the samples were stored at 5degC, no toxic samples were found up to 30 days of storage when the experiment were terminated. The percentage of toxic samples was shown highly effected by type B strains, fish species, inoculum levels and storage time, when the storage temperature is 20degC. But no significant difference was found after treatment with irradiation doses. In general the interaction effects between those treatments on the percentage of toxic samples showed no significant difference. (author)

[en] Soy as one of the most important crops after rice is generally cultivated in the lowland and very rare or almost none in the highlands. A mutation breeding programme was just started in 1977 (at Bandung Reactor Center) with the aim to select some improved types of soybean, e.g., early flowering and maturing time, adaptation to high altitude, good determinate plant type and higher in yield. In M-2 generation, 123 plants with desirable plant type were isolated and grown as M-3 mutant lines for confirmation their stability and homogeneity. 19 stable and homogeneous mutants derived from M-3 lines were investigated and will be grown in M-4 for yield tests. A few early maturing plants (3-7 days earlier), 2 mutant lines which were very late in flowering and with indeterminate growth habit were found. (author)

[en] The degradation of the mechanical properties of zircaloy-4 as nuclear fuel cladding is inevitable due to its interaction with hydrogen during normal reactor operation. This experiment observed the occurrence of hydride phases after gaseous hydriding with hydrogen at elevated temperature, and their effects were evaluated based on the material's microstructure and mechanical properties. The zircaloy-4 cladding materials were annealed for two hours. It was followed by hydriding with the pressure from 100 up to 1200 mbar at various temperatures of 350 °C, 500 °C, 550 °C and 600 °C. The pressure-composition-isotherm (PCI) diagram showed that the hydrogen absorbed by specimen namely 0.18 % wt, 0.38 % wt, 0.44 % wt and 0.74 % wt at 350 °C, 500 °C, 550 °C and 600 °C, respectively. This result confirmed that the hydrogen content were 10, 128, 250, and 1357 ppm at 350 °C, 500 °C, 550 °C, and 600 °C, respectively, as measured by an ONH analyzer. X-ray diffraction showed that δ-hydride peaks were very weak based on fitting with the hydride database. The results from optical microscope and scanning electron microscope confirmed the presence of hydrides at the specimens, identified by the growth of needle-like structure at those temperatures. (author)

[en] Nuclear kinetic calculations based on point kinetic model have been generally applied as the standard method for neutronics codes. As the central control rod (C-CR) withdrawal test has demonstrated in a prismatic core type high-temperature gas-cooled reactor (HTGR) named High Temperature Engineering Test Reactor (HTTR), the transient calculation of kinetic parameter, reactivity, and neutron fluxes, requires a new method to shorten calculation-process time. Development of neural network method was applied to point kinetic model as the necessity of real-time calculation that could work in parallel with the digital reactivity meter. The combination of Time Delayed Neural Network (TDNN) and Jordan Recurrent Neural Network (Jordan RNN) named TD-Jordan RNN was the result of the modeling approach. The application of TD-Jordan RNN with adequate learning, tested offline, determined results accurately even when signal inputs were noisy. Furthermore, the preprocessing for neural network input utilized noise reduction as one of the equations to transform two of twelve time-delayed inputs into power corrected inputs. (author)