The application of flux cored arc welding (FCAW) has increased in manufacturing and fabrication. Even though FCAW is well known for its good capability in producing quality welds, few reports have been published on the cause of the relatively high diffusible hydrogen content in the weld metal and its relation with the ingredients used in the wire production and with the welding parameters (mainly welding current). This paper describes experiments where data obtained from weld metal diffusible hydrogen analysis, metal droplet collection, and high-speed recording of metal droplet transfer were used to evaluate the effect of welding current on diffusible hydrogen content in the weld metal. The results from gas chromatography analysis showed that weld metal hydrogen content indeed increased with welding current. A polynomial regressional analysis concluded that hydrogen increase with current was better described by a linear function with proportional constant of approximately 0.7 or 70%. Different from the GMA welding transfer behavior, statistical analysis showed only a small increase in metal droplet size with increasing current. The metal transfer mode remained in the globular range for currents between 100 and 150 A. The most surprising findings were with the high-speed cinematography recording. Observing the high speed movies, it was possible to see that at low current, "unmelted" flux sporadically touched the weld pool but at higher current, the flux remained touching the weld pool during the whole time of droplet formation and transfer. It is believed that since the flux has ingredients that contain hydrogen, hydrogen passes through the arc undisturbed, going to the weld bead intact and increasing the hydrogen content in the weld metal. Another important observation is regarding to droplet size. Droplet size increased with increasing current because forces from decomposed gases from the flux could sustain the droplets, retarding their transfer and allowing them to grow

No século XIX, a abordagem dos químicos em relação à produção química era semelhante à construção de um mecanismo, um processo de cada vez, separadamente e individualmente, como se cada processo fosse incompatível com todos os outros. A criação da engenharia química introduziu princípios científicos que tornaram possível generalizar práticas e racionalizar os processos de produção, levando ao desenvolvimento da indústria química. Palavras chave: história; engenharia química; indústria química.In the nineteenth century, the chemists' approach to chemical production was similar to building a mechanism, one process at a time, separately and individually, as if each process were incompatible with all others. The creation of chemical engineering introduced scientific principles that made it possible to generalize practices and rationalize production processes, leading to the development of the chemical industry.

O trabalho estudou a cinética de biossorção do corante Acid Blue 324 pela cianobactéria Spirulina maxima. Avaliou-se a capacidade de remoção da cor do referido corante, o qual foi adicionado à cultura da cianobactéria Spirulina maxima. Foram avaliados dois fatores, a concentração de nitrato e a concentração de corante. O estudo demonstrou bons resultados na remoção do corante do meio de cultura com redução expressiva da cor, alcançando valores acima de 80% na remoção da cor na cultura. Palavras-chave: acid blue 324; Spirulina maxima; biossorção.The work studied the biosorption kinetics of the dye Acid Blue 324 by the cyanobacteria Spirulina maxima. It was evaluated the color removal capacity of the said Dye, which was added to the culture of the cyanobacteria Spirulina maxima. Two factors were evaluated, the concentration of nitrate and the concentration of dye. The study demonstrated good results in the removal of the dye from the culture medium with expressive reduction of the color, reaching values above 80% in the removal of the color in the culture.

Compósitos de Polietileno de Baixa Densidade (PEBD), reforçados com sílica precipitada em presença de Viniltrimetoxi Silano (VTMS), destinados a composições de dutos de petróleo, foram obtidos e caracterizados. As composições foram processadas por extrusão variando o teor de sílica na matriz de PEBD em 1%, 3% e 5%, com e sem a presença do VTMS. O comportamento reológico das composições foi investigado durante o processamento, mostrando que a presença do silano provocou redução do valor médio do torque e viscosidade e dispersão da carga. Tais resultados foram corroborados pela Microscopia Eletrônica de Varredura com Espectroscopia de Raios X por Dispersão de Energia (MEV-EDS), exibindo, de um modo geral, melhor dispersão da carga na matriz polimérica e melhor processabilidade. Os resultados permitiram também inferir a possibilidade de ganhos de propriedades mecânicas e dinâmicas para tais composições.