This work presents a new clock reaction based on ozone, iodine, and chlorate that differs from the known chlorate-iodine clock reaction because it does not require UV light. The induction period for this new clock reaction depends inversely on the initial concentrations of ozone, chlorate, and perchloric acid but is independent of the initial iodine concentration. The proposed mechanism considers the reaction of ozone and iodide to form HOI, which is a key species for producing non-linear autocatalytic behavior. The novelty of this system lies in the presence of ozone, whose participation has never been observed in complex systems such as clock or oscillating reactions. Thus, the autocatalysis demonstrated in this new clock reaction should open the possibility for a new family of oscillating reactions.

This work presents a new oscillating reaction based on chlorate and observed in a CSTR at room temperature. This can be the first member of a new family of oscillating reactions. In addition, it is also the first oscillating reaction to use nitrous acid as a reactant. Four different behaviors were observed: simple oscillations, mixed mode oscillations, bursts, and quasiperiodicity. The period of oscillations is very short, which is around 1 s. Together with the fact that it also shows fast bursts, it opens the possibility that it can be used to simulate fast biological events, like the neuron's communications signals.

No abstract

As 2019 is the 150th anniversary of the Mendeleev's Periodic Table , UNESCO has proclaimed this year the International Year of the Periodic Table (IYPT2019). One of the most important steps in the evolution of the Periodic Table is the concept of atomic number, established by Moseley. In this article, his work is commented on, and the emission of X-ray lines is interpreted on the basis of a one-electron transition using Bohr's theory. The agreement is very good for the Kα and Kβ lines, which can be used in classes to reinforce the quantized model of atoms. It is also shown that inner-electron-screening effects play a significant role, especially in the L-series lines. In addition to the discussion based on Bohr's theory, the several different X-ray lines that are known for each element are also explained using LS spin−orbit-coupling spectroscopic terms. The presentation of X-ray data and discussion of the data using these two theoretical approaches in both undergraduate and graduate classes resulted in significant grade improvements on the topic of atomic theory.