A method of separation and spectrometric analysis with aNaI (Tl) scintillator of longlived radionuclides in sea water, to be released from nuclear installations, was investigated. When co-precipitation of the nuclides with hydrated ferric hydroxide was carried out by adding pyridine instead of ammoniacal water, Fe-59, Zr-95, Ce-144andRu-106could be co-precipitated with >95% yield, whileSr-90andCs-137were not precipitated at all. Co-precipitation ofCo-60andZn-65were very little. The results can be explained by the fact that pH of the solutions at the precipitation could be adjusted to 6-7 easily and accurately, and that a few of the metal ions formed their pyridine complexes. Experiments with varying the amounts of pyridine and/or Feadded to sea water revealed the co-precipitation behaviors of each radionuclide in detail.
Radiation-induced oxidation of ferrous ions in 0.8N hydrochloric acid solutions were investigated using a 45 kCi60Co-γ ray source. It will be shown that the system is suitable for high-level dosimeter up to 40 Mrads. The reaction mechanism, dose rate dependence, and temperature dependence of the radiolytic yield as well as the thermal stability of the system are also reported.
It would be helpful to the understanding of the behavior of molten metal in a mold and the elucidation of its “run”, an important factor in the making of castings, to determine the distribution of each portion of molten metal and its mixing state caused by convection during its solidification process. In this study, the distribution of molten metal in a mold was investigated by the activable tracer method, with a real casting part. Au and Ir were used as the tracer elements, which were not originally included in the casting material and highly sensitive to the neutron activation method. In the preliminary experiment with a simpler mold, it was revealed that 0.005% addition was sufficient for either Au or Ir to be fully detected after 5 hr irradiation with a neutron flux of 2×1011n/cm2/sec, followed by 24 hr of cooling and that the sampling for radiation detection should be carefully made because of incomplete mixing state of molten metal even in a preferred area. The mold in the experiment was a sand mold for the production of a cylinder head of an automotive engine. Molten metal was poured in three charges. The first charge contained Au, the second Ir and the third no tracer. About 10 g of sample was taken from each appropriate part of the casting, and subjected to the irradiation by neutrons with a flux of 2×1011n/cm2/sec. The content percents of the first and second charges were determined from the measurement of the photo-peak area of gamma-rays at 0.41 (Au) and 0.31 (Ir) MeV, respectively. The remainder was assigned to the third charge. From these observations, it was clarified that the first charge settled in the lower part in the mold, farthest from the sprue runner. The second and third charges tended to solidify in more upper layers. However, in some portions in the mold was definitely observed some degree of mixing by convection.
A Res-O-Mat ETR test is used for an in vitro measurement of free thyroxine index which has been otherwise determined by calculation from the results of T3-test and T4-test. Res-O-Mat ETR tests were measured in 120 sera from the euthyroid patients, patients with thyroid dysfunction or with TBG abnormality. The reproducibility test with the same sera was satisfactory. Res-O-Mat ETR test showed almost the same accuracy as T4-test or T3-test did in serum from the patient without TBG abnormality. In the sera with TBG abnormality, this test represents the thyroid function more accurately than T4-test or T3-test. Results of this test and free thyroxine index calculated from the results of T4-test and T3-test, show a good linear correlation.
Estimation of total serum T4concentration (Res-O-Mat T4) and T3uptake test (Res-O-Mat T3) are available blood parameters of thyroid function. But these parameters are often deviated from normal in pregnancy, nephrosis, livercirrhosis and other cases of abnormal TBG values. The Res-O-Mat ETR test is a single in vitro thyroid function test which can simultaneously consider both the binding capacity of the TBG (Res-O-Mat T3) and the total serum T4concentration (Res-O-Mat T4) . The results of our studies have shown the ETR values to have a higher degree of correlation with the concentration of free T4 in the serum. The ETR values have shown more correctly the clinical thyroid status of the patients than the results of either a T3 uptake or T4 test alone. The ETR values, in addition, indicated the thyroid function correctly in aforesaid nonthyroidal patients.
57Co-BLM has an affinity for tumor. There is little possibility that the affinity for tumor of57Co-BLM is due to vascularity of tumor or any secondary change in the adjacent tissues. The results of our present study suggest the dissimilarity of57Co-BLM to BLM (copper free) in property and, moreover, the lesser toxicity of the former substance. All these results, including data relevant to exposure dose, may be considered to warrant the clinical use of57Co-BLM.