Abstract Mesoporous TiO2 nanoparticles were synthesized by the sol-gel method and using hydrothermal treatment at 200 ºC during different time intervals, which allowed the evaluation of the time or the treatment on the structural, morphological, and optical properties of the oxides. TEM micrographs showed that the morphology of the materials was characterized by the presence of spherical clusters, while the crystalline phases of the anatase and brookite mixtures were analyzed by X-ray diffraction and Raman spectroscopy. A type IV profile was identified from the results of specific surface area, which is characteristic of the mesoporous material with strong and weak affinity. The band gap in the range of 3.29 and 3.40 eV, estimated by the Kubelka-Munk function, showed a gradual increase as a result of oxide crystallization. It was found that 8 h of treatment in a hydrothermal system was sufficient to synthesize a photocatalyst with optimal photocatalytic performance. This efficiency was probably based on a good correlation between physical and chemical factors, such as high surface area and porosity, the improved capability of photon adsorption in the visible range, crystallinity, and a favorable content of brookite.

Este trabalho apresenta um estudo de viabilidade econômico financeira para a implantação de uma central de massa, com o objetivo de preparar a argila antes do processo produtivo, utilizando-se de técnicas adequadas e apropriadas, que proporcionam economia de matéria-prima, redução do consumo de energia elétrica, redução do consumo de energia térmica, aumento da produtividade, entre outros benefícios. Foram realizadas simulações em três tipos de cenários: pessimista, mais provável e otimista. Utilizaram-se os métodos tradicionais de avaliação: VPL, TIR e Payback Descontado. Em todos os três cenários os resultados determinam que o investimento é viável.

This paper presents a study of economic and financial viability for central mass implementation, with the aim of preparing the clay before the production process, using appropriate techniques and fitting, that providing savings in raw materials, reduce the consumption electricity, reduction of thermal energy consumption, increased productivity, among other benefits. We simulated three types of scenarios: pessimistic, most likely and optimistic. We used the traditional assessment methods: NPV, IRR and Discounted Payback. In all three scenarios the results determine that the investment is viable.

Spodoptera frugiperda, a lagarta-do-cartucho-do-milho, é uma praga polífaga de grande importância agrícola pelos danos e dificuldade de controle. A ausência de informações sobre seu impacto em milho doce motivou a comparação de sua biologia, no que tange as fases larval e pupal, entre os genótipos de milho ELISA, BR 400 (milhos doces) e BR PAMPA (milho comum). Em condições de laboratório (25 ± 1ºC; 70 ± 10% UR; fotofase 12 horas), 35 lagartas foram individualizadas e alimentadas, diariamente, com seções de folhas de 3,14 cm² dos referidos genótipos, provenientes de parcelas estabelecidas na área experimental do Departamento de Fitossanidade, UFRGS, Porto Alegre, RS, de outubro a novembro de 2000. As lagartas foram pesadas diariamente e após cada ecdise as cápsulas cefálicas eram recolhidas e mensuradas quanto à largura, para estabelecer a razão de crescimento. As pupas foram pesadas e sexadas com 24 horas de idade. Avaliaram-se a duração dos ínstares larvais, a razão sexual das pupas e a mortalidade larval e pupal. Não se registrou diferença na largura das cápsulas nos três primeiros ínstares. No quarto e quinto ínstares, as cápsulas das lagartas mantidas em BR 400 foram menores. O peso das lagartas e das pupas, a duração dos ínstares e a razão sexual não diferiram entre os genótipos. A duração da fase pupal foi menor nas fêmeas mantidas em BR 400. A mortalidade foi maior, na fase larval, em ELISA e, na pupal, em BR PAMPA.

Spodoptera frugiperda, the fall armyworm, is a very significant polyphagous pest due to the damages it causes, and control difficulties. Lack of information about its impact on sweet corn motivated a comparison of its biology, with respect to the larval and pupal stages, among the genotypes ELISA, BR 400 (sweet corns), and BR PAMPA (field corn). In laboratory conditions (25 ± 1ºC; 70 ± 10% RH; photophase 12 hours), 35 caterpillars were individualized and fed daily with 3.14 cm² sections of corn leaves from the referred-to genotypes, cultivated in plots in the experimental area of the Departament of Fitossanidade, UFRGS, Porto Alegre, RS from October to November 2000. The caterpillars were weighed daily; after each molt, the cephalic capsules were collected and measured (in width), to establish growth rate; pupae were weighed and sexed when 24 hours old. The duration of the larval instars, the pupal sex ratio, and the mortality of larvae and pupae were evaluated. In the first three instars there were no differences registered in capsule width. In the fourth and fifth instars, capsules of caterpillars kept in BR 400 were smaller. The weight of caterpillars and pupae, instar duration and sex ratio did not differ among the genotypes. Pupal phase duration was less in females kept in BR 400. Mortality was greater in the larval phase in ELISA and in the pupal phase in BR PAMPA.