RESUMO
The paper presents results of the studies photodegradation, photooxidation, and oxidation of phenylarsonic acid (PAA) in aquatic solution. The water solutions, which consist of 2.7 g dm(-3) phenylarsonic acid, were subjected to advance oxidation process (AOP) in UV, UV/H2O2, UV/O3, H2O2, and O3 systems under two pH conditions. Kinetic rate constants and half-life of phenylarsonic acid decomposition reaction are presented. The results from the study indicate that at pH 2 and 7, PAA degradation processes takes place in accordance with the pseudo first order kinetic reaction. The highest rate constants (10.45 × 10(-3) and 20.12 × 10(-3)) and degradation efficiencies at pH 2 and 7 were obtained at UV/O3 processes. In solution, after processes, benzene, phenol, acetophenone, o-hydroxybiphenyl, p-hydroxybiphenyl, benzoic acid, benzaldehyde, and biphenyl were identified.
Assuntos
Arsenicais/química , Purificação da Água/métodos , Meia-Vida , Concentração de Íons de Hidrogênio , Hidrólise , Cinética , Espectrometria de Massas , Oxirredução , Ozônio/química , Fotólise , Fatores de TempoRESUMO
Three methods to describe biped locomotion as well as manipulation activity are presented. Methods using so-called couple oscillators as rhythm generators are described. Based on a mathematical model, results of computer simulation of biped locomotion are presented. An indices method of assessing human gait for both normal and pathological cases was proposed and tested. The results showed that it is relatively easy to distinguish different gaits by using this method. This method was tested in clinical conditions. The third method deals with the problem of supporting the lost function of prehension movements. Implanted stimulators on the nerves combined with external orthoses were used. The clinical results show that these methods have practical advantages.