Solubility of Ethene in Water and in a Medium for the Cultivation of a Bacterial Strain

The solubility of ethene in water and in the fermentation medium of Xanthobacter Py(2) was determined with a Ben-Naim-Baer type apparatus. The solubility measurements were carried out in the temperature range of (293.15 to 323.15) K and at atmospheric pressure with a precision of about +/- 0.3 %. The Ostwald coefficients, the mole fractions of the dissolved ethene, at the gas partial pressure of 101.325 kPa, and the Henry coefficients, at the water vapor pressure, were calculated using accurate thermodynamic relations. A comparison between the solubility of ethene in water and in the cultivation medium has shown that this gas is about 2.4 % more soluble in pure water. On the other hand, from the solubility temperature dependence, the Gibbs energy, enthalpy, and entropy changes for the process of transferring the solute from the gaseous phase to the liquid solutions were also determined. Moreover, the perturbed-chain statistical associating fluid theory equation of state (PC-SAFT EOS) model was used for the prediction of the solubility of ethene in water. New parameters, k(ij), are proposed for this system, and it was found that using a ky temperature-dependent PC-SAFT EOS describes more accurately the behavior solubilities of ethene in water at 101.325 kPa, improving the deviations to 1 %.

Exposure and genotoxicity assessment methodologies: the case of formaldehyde occupational exposure

Formaldehyde (FA) ranks 25th in the overall U.S. chemical production, with more than 5 million tons produced each year. Given its economic importance and widespread use, many people are exposed to FA occupationally. Recently, based on the correlation with nasopharyngeal cancer in humans, the International Agency for Research on Cancer (IARC) confirmed the classification of FA as a Group I substance. Considering the epidemiological evidence of a potential association with leukemia, the IARC has concluded that FA can cause this lymphoproliferative disorder. Our group has developed a method to assess the exposure and genotoxicity effects of FA in two different occupational settings, namely FAbased resins production and pathology and anatomy laboratories. For exposure assessment we applied simultaneously two different techniques of air monitoring: NIOSH Method 2541 and Photo Ionization Detection Equipment with simultaneously video recording. Genotoxicity effects were measured by cytokinesis-blocked micronucleus assay in peripheral blood lymphocytes and by micronucleus test in exfoliated oral cavity epithelial cells, both considered target cells. The two exposure assessment techniques show that in the two occupational settings peak exposures are still occurring. There was a statistical significant increase in the micronucleus mean of epithelial cells and peripheral lymphocytes of exposed individuals compared with controls. In conclusion, the exposure and genotoxicity effects assessment methodologies developed by us allowed to determine that these two occupational settings promote exposure to high peak FA concentrations and an increase in the micronucleus mean of exposed workers. Moreover, the developed techniques showed promising results and could be used to confirm and extend the results obtained by the analytical techniques currently available.

Projectos estratégicos: o controlo orçamental - estudo da construção de redes de nova geração por parte da Zon

O objectivo deste trabalho foi o de descrever a forma como muitas empresas seleccionam os projectos que são implementados, sobretudo os seus projectos estratégicos, dando principal enfoque à forma como procederam ao seu controlo orçamental. Como tal, tentámos explorar e explicar, quais as componentes necessárias para a análise de um investimento, abordando a temática dos projectos de investimento estratégicos da empresa e a sua relação com a estratégia definida a curto prazo, assim como no médio e longo prazo. Após a selecção do projecto a implementar, é necessário um controlo da sua execução, de forma a poder controlar os custos e a rentabilizar de forma eficiente os recursos disponibilizados, na execução do investimento. Para isso, abordámos de seguida a função do controlador de gestão, a importância de elaborar o orçamento e o controlo orçamental. Após estas fases, analisamos os relatórios de controlo mais usuais. Depois da revisão da literatura, estudámos dois dos investimentos estratégicos efectuados pela ZON nos últimos anos, para tornar a sua rede, numa rede de nova geração. Esses investimentos são a construção de rede de acesso FTTH e o projecto ZON IN. Foi possível demonstrar a importância estratégica de ambos os projectos, sendo que não se conseguiu demonstrar a importância do controlo orçamental.