The effect of organic additives in electrodeposition of Co from an amide-type ionic liquid

The effect of organic additives, coumarin and thiourea (TU), on the electrodeposition of cobalt (Co) was investigated in an amide-type ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA), containing Co(TFSA)₂ as a Co source. In case of addition of coumarin, the deposition potential of Co shifted to the positive side while there was no change in the coordination environment of Co²⁺. However, the surface morphology was changed by addition of coumarin, suggesting the specific adsorption of coumarin on the surface of electrode. On the other hand, the deposition potential of Co shifted to the more positive side by addition of TU, probably due to the change in the coordination environment of Co²⁺ from [Co(TFSA)₃]⁻ to [Co(TU)₄]²⁺. The diffusion coefficient of [Co(TU)₄]²⁺ was determined as 7.2 × 10⁻⁸ cm² s⁻¹ at 27 °C by chronoamperometric method. The surface morphology of electrodeposit obtained from the electrolyte with TU was flat and less granular as compared to that without TU.     

Long-term thermal stability of Li4TiO4–Li2TiO3 core–shell breeding pebbles under continuous heating in H2/Ar atmosphere

The long-term thermal stability of tritium breeding materials during service is a key factor to ensure efficient tritium release. In this study, the long-term thermal stability of advanced Li₄TiO₄–Li₂TiO₃ core–shell breeding pebbles under continuous heating in 1%H₂/Ar at 900°C was investigated for the first time. The results show that this core–shell material loses 3.4% Li mass after heating for 30 days, resulting in a reduction in Li density to .415 g/cm³, which is still significantly higher than other breeding materials. The moisture in the sample bed will determine the form of Li volatilization and thus affect the rate of Li mass loss. The core–shell pebbles maintain favorable phase stability during long-term heating, and the grain sizes of the Li₂TO₃ shell and Li₄TiO₄ core after 30 days of heating are 6.5 ± 1.5 and 6.9 ± 2.5 μm, respectively. Moreover, the samples did not crack or collapse during long-term heating and still had a satisfactory crushing strength of 37.61 ± 7.13 N after 30 days of heating. Overall, the high Li density and good thermal stability during long-term heating demonstrate that the Li₄TiO₄–Li₂TiO₃ core–shell breeding pebbles are a very reliable tritium breeding material for long-term service under harsh operating conditions.     

Welding phenomena and in-process monitoring in high-power YAG laser welding of aluminium alloy

Laser welding of aluminium alloys is difficult because of their low laser coupling, easy formation of welding defects, etc. and thus the establishment of in process monitoring technique is expected in various industries to obtain highly reliable laser welds. In this study, therefore, both the reflected laser beam and radiation light from die molten pool were investigated as monitoring signals during YAG laser welding of A5052 and A5182 aluminium alloy to confirm validity and usefulness of these signals for monitoring. At the same time, laser-welding phenomena were observed through a high-speed video camera to better interpret the monitored signals. Two signals were detected by utilizing photo sensors and band pass or cut-off filters coaxially against a laser beam and from the above-back direction. In this paper, experimental setup, and monitoring and observation results were presented. The correlation between monitoring signals and welding phenomena was clarified when the welding defects such as underfilling and through holes were formed.     

New Sweet Potato Line having low Gelatinization Temperature and altered Starch Structure

A new sweet potato breeding line, Kanto 116, was developed, featuring low gelatinization temperature and an altered starch fine structure. Starch granules from Kanto 116 showed an abnormal morphology characterized by cracking into granules. Starch content, amylose content and tuberous root appearance of Kanto 116 were similar to those of the control and the parents. Pasting temperatures of Kanto 116 starch determined by the Rapid Visco Analyser were 51.4 — 52.6 °C, approximately 20 °C lower than those of the control and parents starches. Onset, peak, and conclusion temperature of gelatinization, and gelatinization enthalpy of Kanto 116 starch determined by differential scanning calorimetry were 39.0 °C, 46.9 °C, 64.8 °C, and 8.8 J/g, respectively, and much lower than those of the control and parents starches. The chain‐length distribution of the amylopectin molecules, determined by high‐performance anion‐exchange chromatography, showed that Kanto 116 starch had a higher proportion of short chains (DP 6 — 11) and a lower proportion of chains between DP 12 — 28 than control and parent starches. The debranched β‐limit dextrin of Kanto 116 starch also showed that the proportion of both short and long B1 chains was different from those of the control and parents starches.