NUMERICAL APPROACHES FOR A MATHEMATICAL MODEL OF AN FCCU REGENERATOR

This work discusses a mathematical model of an FCCU (Fluid Catalytic Cracking Unit) regenerator. The model assumes that the regenerator is divided into two regions: the freeboard and the dense bed. The latter is composed of a bubble phase and an emulsion phase. Both phases are modeled as a CSTR (Continuously Stirred Tank Reactor) in which ordinary differential equations are employed to represent the conservation of mass, energy and species. In the freeboard, the flow is considered to be onedimensional, and the conservation principles are represented by partial differential equations to describe space and time changes. The main aim ofthis work is to compare two numerical approaches for solving the set of partial and ordinary differential equations, namely, the fourth-order Runge-Kutta and implicit finite-difference methods. Although both methods give very similar results, the implicit finite-difference method can be much faster. Steady-state results were corroborated by experimental data, and the dynamic results were compared with those in the literature (Han and Chung, 2001b). Finally, an analysis of the model’s sensitivity to the boundary conditions was conducted

The impact of temperature on biological aspects and life table of Harmonia axyrids (Pallas) (Coleoptera: Coccninellidae).

The impacts of temperature on Harmonia axyridis and its potential as a control agent of Cinara atlantica, the Carolina conifer aphid, were evaluated. The experiments were conducted with eggs from field-collected adults. Each egg batch was kept at 15 °C, 20 °C and 25°C, 70% RH and 12:12 h. L:D. After hatching, the larvae were reared individually until adult emergence and all insects were kept under the same conditions. The mean period of egg incubation, total developmental time and egg viability were longer at 15 °C that than at the other 2 temperatures. Survival was 100% for all the larval, pre-pupal and pupal stages. The longevity was longer at 15 °C and 20 °C than 25 °C. The mean number of eggs produced was significantly higher at 15°C than at the other 2 temperatures. The post-oviposition period increased with increasing temperature. The highest specific fertility was recorded at 15 °C, followed by 25 °C and 20 °C, respectively. The net reproductive rate was higher at 15 °C than at the 2 higher temperatures. The time interval between each generation (T) decreased with increasing temperature and the population doubling time (DT) was higher at 15 °C than at 20 °C and 25 °C. The intrinsic rates of increase (rm) were very similar at the 3 temperatures, but the finite rate of population increase (?) was higher at 25 °C than at the 2 lower temperatures. The results indicate that H. axyridis shows great potential as a biological control agent of C. atlantica

Avaliação da eficiência do óleo de Neem e estrato de fumo no controle do pulgão do Pinus, Cinara atlantica, em laboratório.

Organizado por Patrícia Póvoa de Mattos, Celso Garcia Auer, Paulo César Botosso e Rejane Stumpf Sberze

Life table analysis and consumption capacity for Harmonia axyridis (Coleoptera: Coccinellidae), feeding on Cinara atlantica (Hemiptera: Aphididae).

he objective of this study was to analyze the development, reproductive parameters and consumption capacity of Harmonia axyridis, using Cinara atlantica as food. The average time of egg incubation was 3 d, duration of larval instars was 3.5, 2, 2.2 and 4.1 d, respectively, and duration of the pupal stage was 5.8 d. Longevity was 85.6 d and the life cycle lasted 107.2 d. Egg viability was 92.7% and all stages had 100% survival. Adults consumed, on average, 1.892 aphids. Pre-oviposition, oviposition and post-oviposition periods lasted 6.8, 44.3, and 32.9 d, respectively. Fertility was 633.2 eggs per female. Each instar consumed, on average, 19.4, 24.8, 49.7 and 188.9 aphids, respectively. The life table results, together with biological data, indicated that Harmonia axyridis is an efficient predator of C. atlantica, having high fertility, egg viability, rapid development and high levels of predation