Pill bugs individually walked an experimental pathway, then were induced to conglobate with a puff of air. After recovering, they were stimulated again. Sixty of 80 pill bugs conglobated both times, first moving either antennae (A) or legs (L) during recovery. Both AA and LL groups showed a significant positive correlation between first (t1) and second (t2) conglobation times. In the AL group, pathway locomotion time (t0) was significantly positively correlated to both t1 and t2. We conclude that pill bugs determine conglobation time based partly on their previous states.
The oxidation states of antimony and tellurium fission products formed in the aqueous solutions of233U and235U irradiated in a reactor were studied by means of anion exchange method. Results were corrected for the thermal reactions
such as radiation induced reactions using double tracers for each element. In hot reactions, the isotopes formed independently
by fission take their reduced states almost completely, whereas the isotopes formed by β-decay of their precursors favor their
oxidized states. The fractions of the tellurium isotopes in the oxidized state depend on the β-decay energy of their precursors,
whereas those of the antimony isotopes are nearly constant irrespective of the β-decay energy. The different behaviors between
those two elements would reflect the chemical properties of their precursors.
Sorption behavior of Am(III) onto granite was investigated. The distribution coefficient (Kd) of Am(III) onto granite was determined in the solution of which pH was ranged from 2.9 to 11.4 and ionic strength was set
at 10−2 and 10−1. TheKd values were found to increase with increasing pH and with decreasing ionic strength. The obtained data were successfully
analyzed by applying an electrical double layer model. The optimum parameter values of the double layer electrostatics and
adsorption reactions were obtained, and the selective adsorption behavior of Am(III) onto the granite was discussed.
Extraction behaviors of Pd(II) in the TRUEX and PUREX solvent extractions were studied by using octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide. The effect of scrubbing in the TRUEX solvent extraction was demonstrated by adding oxalic acid. The distribution ratios of palladium (DPd's) in the diluted region of [HNO3] were found to depend strongly on the fraction of cationic species, Pd(NO3)+, existed in the aqueous phase. The gradual decrease of DPd with the increase of acidity beyond [H+] 1 mol·dm-3 was controlled by the formation of the anionic species Pd(NO3)3-.
Adsorption behavior of fission products in nitric acid solution on various alloys and metals was studied by using a multitracer produced by neutron irradiation of UO2. The adsorption behavior of the fission products 99Mo, 131I, 132Te, 140La, and 143Ce, and 239Np was simultaneously studied. Some chemical decontamination tests were also examined. Clear adsorption of 99Mo, 131I, and 132Te was observed, whereas adsorption of 140La, 143Ce, and 239Np was not. The adsorption characteristics were discussed by considering anion-exchange reaction and surface complexation.
An elemental analysis method using muonic X-rays has been developed. Applying the unique features of the negative muon, this
method enables elemental distribution in an object to be obtained three dimensionally and non-destructively. Especially, by
choosing the incident muon beam energy, depth-profiling as deep as several cm from the surface can be achieved by detecting
the high energy muonic X-rays carrying the information of the atom which captured the muon. We obtained some preliminary results
and showed the applicability of the technique in future analytical facilities.