For many years, we have been involved in the development of separation and analytical methods for chemical substances using the properties of ions, as well as recycling methods for resources. Separation and concentration of harmful or useful ions are fundamental problems, and suppression or removal of harmful components from the waste, which is still difficult to solve, is a social problem in terms of recycling. The reaction system involving ions is the basis of chemical reactions, and the combination of acid-base reactions, complex formation reactions, and redox reactions is very profound. I would like to look back on what I have been working on with these themes.

A new model for predicting beach changes was developed using the cellular automaton method, taking sand transport under the ongoing and outgoing waves into account independently. The model was applied to predict sand deposition on the backshore with a steep foreshore slope on the Oiso coast. Furthermore, three-dimensional topographic changes were predicted using the model, when a groin with an opening between the landward end of the groin and the land was constructed on a beach. The predicted beach changes well explained the observation results on the Osawa coast facing the Uraga Strait.