Selection of desulfurizing agents and optimization of operational variables in hot metal desulfurization

The growing demand for steels with tighter compositional specifications led the Companhia Siderúrgica Nacional (CSN) to develop more efficient processes. To solve this problem this paper aims to identify the operational variables more impacting in the desulfurization process, specifically in torpedo car, as well as its causes and solutions. Then select and test, with laboratorial and industrial tests, desulfurizing agents based of CaC 2, CaO, CaCO3, and Mg to assess the cost per quantity of product desulfurized. The mixture with best results was not that one with highest content of CaC2. It is believed that this mixture showed better efficiency because of the increased agitation of the bath, produced by the releasing of gas from compound CaCO3 present in this mixture. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An integrated macro-model for the Caribbean subregion

Includes bibliography

The effects of growth and economic reform on income distribution in Latin America

Includes bibliography

Physicochemical and mechanical properties of zirconium oxide and niobium oxide modified Portland cement-based experimental endodontic sealers

Aim: To evaluate the physicochemical and mechanical properties of Portland cement-based experimental sealers (ES) with different radiopacifying agents (zirconium oxide and niobium oxide micro- and nanoparticles) in comparison with the following conventional sealers: AH Plus, MTA Fillapex and Sealapex. Methodology: The materials were tested for setting time, compressive strength, flow, film thickness, radiopacity, solubility, dimensional stability and formaldehyde release. Data were subjected to anova and Tukey tests (P < 0.05). Results: MTA Fillapex had the shortest setting time and lowest compressive strength values (P < 0.05) compared with the other materials. The ES had flow values similar to the conventional materials, but higher film thickness (P < 0.05) and lower radiopacity (P < 0.05). Similarly to AH Plus, the ES were associated with dimensional expansion (P > 0.05) and lower solubility when compared with MTA Fillapex and Sealapex (P < 0.05). None of the endodontic sealers evaluated released formaldehyde after mixing. Conclusion: With the exception of radiopacity, the Portland cement-based experimental endodontic sealers presented physicochemical properties according to the specifications no 57 ANSI/ADA (ADA Professional Product Review, 2008) and ISO 6876 (Dentistry - Root Canal Sealing Materials, 2012, British Standards Institution, London, UK). The sealers had setting times and flow ability that was adequate for clinical use, satisfactory compressive strength and low solubility. Additional studies should be carried out with the purpose of decreasing the film thickness and to determine the ideal ratio of radiopacifying agents in Portland cement-based root canal sealers. © 2013 International Endodontic Journal.

O brinquedo do parque: um conceito lúdico como arte do reaproveitamento

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Implementação de um controlador PID embarcado para o controle em malha fechada de um estimulador neuromuscular funcional

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Informe del II Taller de Gerentes de Organismos de Cuenca en América Latina y el Caribe = Report on the Second Workshop for Managers of River Basin Authorities in Latin America and the Caribbean

Incluye Bibliografía

Retificador boost entrelaçado com elevado fator de potência e sem ponte de diodos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Controle automático com estrutura variável utilizando sistemas ERP e LMI

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Gestão de desvios técnicos no recebimento de medicamentos na Central de Abastecimento Farmacêutico

Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB

Variabilidade espacial e diagnóstico da qualidade do processo em semeadura de amendoim

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Qualidade e rendimento do leite de soja da unidade de produção de derivados da soja - Unisoja - FCF/Unesp

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Dosagem de etanol utilizando alcool desidrogenase de levedura de panificação

Pós-graduação em Alimentos e Nutrição - FCFAR

Avaliação da resistência de união entre dentina preparada por laser e um sistema adesivo a base de silorano, variando a técnica de aplicação e umidade do substrato

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo dos procedimentos utilizados para obtenção de microrretenções na superfície interna da porcelana: avaliação por meio de testes de rugosimetria e microscopia eletrônica de varredura

Pós-graduação em Ciências Odontológicas - FOAR