2 resultados para Di Domenico, G.
em Brock University, Canada
Resumo:
Kinetics and product studies of the decompositions of allyl-t-butyl peroxide and 3-hydroperoxy- l-propene (allyl hydroperoxide ) in tolune were investigated. Decompositions of allyl-t-butyl peroxide in toluene at 130-1600 followed first order kinetics with an activation energy of 32.8 K.cals/mol and a log A factor of 13.65. The rates of decomposition were lowered in presence of the radical trap~methyl styrene. By the radical trap method, the induced decomposition at 1300 is shown to be 12.5%. From the yield of 4-phenyl-l,2- epoxy butane the major path of induced decomposition is shown to be via an addition mechanism. On the other hand, di-t-butYl peroxyoxalate induced decomposition of this peroxide at 600 proceeded by an abstraction mechanism. Induced decomposition of peroxides and hydroperoxides containing the allyl system is proposed to occur mainly through an addition mechanism at these higher temperatures. Allyl hydroperoxide in toluene at 165-1850 decomposes following 3/2 order kinetics with an Ea of 30.2 K.cals per mole and log A of 10.6. Enormous production of radicals through chain branching may explain these relatively low values of E and log A. The complexity of the reaction is indicated a by the formation of various products of the decomposition. A study of the radical attack of the hydro peroxide at lower temperatures is suggested as a further work to throw more light on the nature of decomposition of this hydroperoxide.
Resumo:
This is a study of education students’ conceptions of and experiences with academic stress and help-seeking. The study explored teacher education and Master of Education students’ academic stress by examining causes of academic stress and how these stressors affect students’ academic and university experiences. Stress-related help-seeking was also a focus of this study, and was explored using inquiries regarding where participants sought stress-related support. Additionally, exploring students’ use of the Internet for stress-related information or support was a goal of this study. These research goals were pursued using a qualitative methodology that applied grounded theory design. Consequently, data were used to develop a theory that would contribute to existing literature. Specifically, participant descriptions related to causes of and responses to academic stress aligned with Maslow’s (1954) theory of human motivation and Alderfer’s (1969) E. R. G. theory, and led to theoretical contributions that took a hierarchy of student needs and motivation into consideration.