Vibrations of probe used for the defect detection of helical heating tubes in a fast breeder reactor: Part 2. Vibration analysis and numerical simulations

A detection of a defect of a helical heating tube installed in the fast breeder reactor “Monju” in Japan is done by a feeding of an eddy current testing (ECT) probe with magnetic sensor into the tube. An undesirable vibration of the ECT probe always happens under a certain condition and makes the inspection difficult. Several characteristics of the vibration have been made clear by some experiments using a mock-up, but the essential factor of the vibration is still unclear. In this paper, a numerical simulation of the vibration is implemented on the assumption that the vibration is caused by Coulomb friction. An analytical model, which is obtained as a lumped mass model, is a large-scale non-linear vibration system and many computational costs are ordinarily required to carry out the simulations. The Transfer Influence Coefficient Method is applied so that the simulation is efficiently carried out. The results of simulation qualitatively agree well with the experimental results. It confirms the validity of the assumption that the vibration is caused by Coulomb friction.     

Tocopherol distribution and molecular species of triacylglycerols in soybean embryonic axes

Soybean embryonic axes were separated from other tissues, i.e., the cotyledons and seed coat. The molecular species and FA distribution of TAG isolated from total lipids in the embryonic axes were analyzed by a combination of argentation-TLC and GC, and were investigated in relation to their tocopherol distribution, which was determined by HPLC. The dominant components were γ-tocopherols, with much smaller amounts of α-, β-, and δ-tocopherols. A modified argentation-TLC procedure, developed to optimize the separation of the complex mixture of total TAG, provided 16 different groups of TAG, based on both the degree of unsaturation and the total acyl-chain length of FA groups. With a few exceptions, the major TAG components were S₂D (6.8–10.3%), SMD (6.9–11.2%), SD₂ (7.2–9.8%), SMT (3.2–7.4%), SDT (11.5–19.5%), D3 (3.5–8.3%), MDT (4.5–7.7%), D₂T (11.1–20.6%), and DT₂ (8.2–15.7%) (where S denotes saturated FA, M denotes monoenes, D denotes dienes, and T denotes trienes). These results indicate that there were significant differences (P<0.05) not only in tocopherol distribution but also in the molecular species of TAG among the four cultivars. Therefore, these tissues should be made available as raw materials for soybean-germ oil or soy milk, based on the differences in the distributions of tocopherol homologs and the molecular species of TAG within the embryonic axes.