The changes in ion-exchange characteristics of synthetic mordenite ground by a planetary ball mill under dry conditions were investigated using radioisotopes of 137 Cs and 85Sr as tracers. The self-diffusion of Cs+ in the mordenite sample was facilitated in the initial stage of grinding, while it was leveled off for the further operation. The relative amount of Cs+ immediately exchanged in the mordenite sample was gradually styptic to a constant value with increase in grinding time after showing a rapid reduction in amount in the early stages of grinding. High selectivity of the mordenite sample for Cs+ against Sr2+ observed in acidic solution diminished obviously with an increase in grinding time.
In many tree breeding programs, plus trees have been selected according to growth rate or stern form in trees. Trees that have a high growth rate or good stern form do not always produce industrially desirable wood. Therefore criteria for wood quality should be considered in tree breeding programs. The objective of this study is to obtain the basic knowledge for breeding for wood quality in Paraserianthes falcataria, an important commercial tree species of Indonesia. Variation in the growth, log properties, basic density, and fiber length in 13-year-old P. falcataria was investigated. Even though all trees were the same age, diameter at breast height showed high variation, indicating a significant variance in the growth rate of seedlings. Significant differences in the log properties (green density, dynamic Young's modulus, and stress-wave velocity) were observed among the trees. Basic density showed a constant value up to 10 cm from pith, at which point it began to increase. The fiber length increased up to 10 cm from the pith and then showed an almost constant value. According to the radial variation of the basic density and fiber length, wood is categorized as core wood, which includes that up to 10 cm from the pith, and outer wood, which is that from 10 cm to the bark. In addition, a significant difference in the basic density of core wood was observed among the trees, indicating that the selection of a plus tree with high-density wood in this species is possible at a relatively early stage. These results indicate that the wood quality in P. falcataria can be improved through tree breeding.