Avaliação da biodessulfurização de 4-metildibenzotiofeno por Rhodococus rhodochrous (NRRL B-2149)

Crude oil has between 0.04 up to 5% of sulphur, the higher the oil the higher the sulphur levels. Sulphur usually gives problems such as corrosion in refinery, and once burnt produces SO2 that goes to atmosphere. This work aim to investigate the capacity of Rhodococcus rhodochrous (NRRL B-2149) to metabolize the model compound 4-methyldibenzotiophene (4-MDBT), to remove the sulphur and transform it in 2-hydroxybiphenyl (2-HBF) and sulphite using the 4S pathway. Kynetic runs were carried out in shaker at 120 rpm and 32°C. Samples were taken every 12h to assay substrate consume as well as cells production using HPLC. Results showed that R. rhodochrous NRRL B-2149 can use the 4S pathway in order to remove sulphur without change the carbon chain of the molecule as well as that cells and 4-MDBT affects the product formation. The production of 2-hydroxybiphenyl has interest for industry once it is a potent biocide. However, evaluation is necessary in order to obtain better results compatible with industry needs

Identidade rural e agricultura familiar :O Pronaf B sob a ótica dos beneficiados

This work has for objective to analyze the perception of benefited of Pronaf B Programa Nacional de Fortalecimento da Agricultura Familiar, in relation to the results that are presented concerning this program. For this, it is presented hypothesis of that the familiar agriculturists, fit in the norms of credit of Pronaf B, have a peculiar perception on the end item of this program, produced from inherent characteristics to the agricultural reality where they live. Ahead of this, I broke myself of estimated of that the searched familiar agriculturists are more socially vulnerable to the inaqualities the agricultural areas. For this research, they had been used, mainly, theoretical reflections of studious of the campesinato, familiar agriculture and of researchers of the impacts of Pronaf B in the agricultural way. The empirical data of the research had been gotten, through the application of questionnaires with the benefited ones and interviews with the mediators of this program in the two searched cities, Apodi and Antônio Martins, in the Rio Grande do Norte, who proportionally withholds the biggest contract number of Pronaf B in the state. The conclusion of the research ratifies the initial hypothesis of that the perception on the results of Pronaf B for benefited its is peculiar, and points stops beyond the economic results, such as: the rise of auto-esteem; the rescue of the citizenship feeling and as impact in autoconsumo of the families of the agriculturists benefited for Pronaf B

Formal verification of PLC programs using the B Method

PLCs (acronym for Programmable Logic Controllers) perform control operations, receiving information from the environment, processing it and modifying this same environment according to the results produced. They are commonly used in industry in several applications, from mass transport to petroleum industry. As the complexity of these applications increase, and as various are safety critical, a necessity for ensuring that they are reliable arouses. Testing and simulation are the de-facto methods used in the industry to do so, but they can leave flaws undiscovered. Formal methods can provide more confidence in an application s safety, once they permit their mathematical verification. We make use of the B Method, which has been successfully applied in the formal verification of industrial systems, is supported by several tools and can handle decomposition, refinement, and verification of correctness according to the specification. The method we developed and present in this work automatically generates B models from PLC programs and verify them in terms of safety constraints, manually derived from the system requirements. The scope of our method is the PLC programming languages presented in the IEC 61131-3 standard, although we are also able to verify programs not fully compliant with the standard. Our approach aims to ease the integration of formal methods in the industry through the abbreviation of the effort to perform formal verification in PLCs