Massao Ionashiro

Bio: Massao Ionashiro is an academic researcher from Sao Paulo State University. The author has contributed to research in topics: Thermal decomposition & Thermogravimetry. The author has an hindex of 23, co-authored 174 publications receiving 2022 citations. Previous affiliations of Massao Ionashiro include Instituto Tecnológico de Aeronáutica.

Thermal degradation of a composite solid propellant examined by DSC

Abstract: The thermal decomposition of ammonium perchlorate (AP)/hydroxyl-terminated-polybutadiene (HTPB), the AP/HTPB solid propellant, was studied at different heating rates in dynamic nitrogen atmosphere. The exothermic reaction kinetics was studied by differential scanning calorimetry (DSC) in non-isothermal conditions. The Arrhenius parameters were estimated according to the Ozawa method. The calculated activation energy was 134.5 kJ mol-1, the pre-exponential factor, A, was 2.04×1010 min-1 and the reaction order for the global composite decomposition was estimated in 0.7 by the kinetic Shimadzu software based on the Ozawa method. The Kissinger method for obtaining the activation energy value was also used for comparison. These results are discussed here.

Gravimetric determination of soil organic matter

Abstract: Studies were carried out to evaluate a gravimetric method for the determination of soil organic matter by the mass loss at 300oC. The gravimetric method was compared with Walkley-Black, using several brazilian soils with variable chemical and physical properties. Gravimetric method was positively correlated with Walkley-Black method with the following linear regression equation: y = 3.72x + 0.29, r = 0.94. The angular coefficient 3.72 for tropical soils was greater than those reported in the literature for temperate soils (from 1.68 to 2.13). The difference was due to greater oxidation degree of the organic matter. When compared with Walkley-Black method, gravimetric technique showed certain distinct advantages such as no environmental contamination with Cr6+ and improved laboratory safety eliminating the use of concentrated sulfuric acid.

Isoconversional Kinetic Analysis of Thermally Stimulated Processes in Polymers

Abstract: Summary: Isoconversional kinetic analysis involves evaluating a dependence of the effective activation energy on conversion or temperature and using this dependence for making kinetic predictions and for exploring the mechanisms of thermally stimulated processes. The paper discusses major results obtained by the authors in the area of the isoconversional analysis of polymer kinetics over the past decade. It provides a brief introduction to isoconversional methods and surveys the impact made by isoconversional analysis in several application areas that include kinetic predictions, thermal degradation, crosslinking (curing), glass transition, and glass and melt crystallization. It is concluded that isoconversional analysis has been used broadly and fruitfully because it presents a fortunate compromise between the single-step Arrhenius kinetic treatments and the prevalent occurrence of processes whose kinetics are multi-step and/or non-Arrhenius. An isoconversional method applies the Arrhenius equation to a narrow temperature region, ΔT related to a given extent of conversion.

Applied photoelectrocatalysis on the degradation of organic pollutants in wastewaters

Abstract: A large variety of electrochemical advanced oxidation processes (EAOPs) have been recently developed to remove organic pollutants from wastewaters to avoid their serious health-risk factors from their environmental accumulation and to reuse the treated water for human activities. The effectiveness of EAOPs is based on the in situ production of strong reactive oxygen species (ROS) like hydroxyl radical ( OH). Photoelectrocatalysis (PEC) has emerged as a promising powerful EAOP by combining photocatalytic and electrolytic processes. It consists in the promotion of electrons from the valence band to the conduction band of a semiconductor photocatalyst upon light irradiation, with production of positive holes. The fast recombination of the electron/hole pairs formed is avoided in PEC by applying an external bias potential to the photocatalyst that extracts the photogenerated electrons up to the cathode of the electrolytic cell. Organics can be oxidized directly by the holes, •OH formed from water oxidation with holes and other ROS produced between the electrons and dissolved O2. This paper presents a general and critical review on the application of PEC to the remediation of wastewaters with organic pollutants. Special attention is made over the different kinds of photocatalysts utilized and preparation methods of the most ubiquitous TiO2 materials. Typical PEC systems and main operation variables that affect the effectiveness of the degradation process are also examined. An exhaustive analysis of the advances obtained on the treatment of dyes, chemicals and pharmaceuticals from synthetic solutions, as well as of real wastewaters, is performed. Finally, research prospects are proposed for the future development of PEC with perspectives to industrial application.