Wood - a renewable resource for production of sugar and biofuel

Albies Alba wood samples were subjected to autohydrolysis extraction at different severities (180, 190 and 200°C), delignification with sodium chloride, and acid hydrolysis of pretreated and delignified substrates. After autohydrolysis pre-treatment under selected operation conditions, cellulose and lignin, in solid phases, and liquors containing hemicellulose products (monosaccharides, oligosaccharides and inhibitory compounds) have been obtained. The purpose of this study is to obtain glucose by autohydrolysis, delignification and acid hydrolysis of fir wood. Fir wood was pretreated at 180, 190 and 200 °C for 5, 10 and 15 minutes, followed by delignification with sodium chloride and acid hydrolysis. The acid hydrolysis of pretreated material and pretreated-delignified material was hydrolyzed using H2SO4 in two stages of impregnation with acid. The results show that elimination of hemicellulose by autohydrolysis pretreatment and lignin by delignification method improve acid hydrolysis yield

Intuitionistic S4 is decidable

In this paper we demonstrate decidability for the intuitionistic modal logic S4 first formulated by Fischer Servi. This solves a problem that has been open for almost thirty years since it had been posed in Simpson's PhD thesis in 1994. We obtain this result by performing proof search in a labelled deductive system that, instead of using only one binary relation on the labels, employs two: one corresponding to the accessibility relation of modal logic and the other corresponding to the order relation of intuitionistic Kripke frames. Our search algorithm outputs either a proof or a finite counter-model, thus, additionally establishing the finite model property for intuitionistic S4, which has been another long-standing open problem in the area.Comment: 13 pages conference paper + 26 pages appendix with examples and proof

Applying of multivariate analysis to study the correlation of mercury and other trace elements distribution in soil from a city from NW Romania

The mercury (Hg) concentrations were evaluated in soils and perennial plants from four districts of Baia Mare city, a historical mining and ore processing center from NW Romania. The results showed that in 24% of the analysed soil samples the mercury concentrations exceeded the guideline value of 1.0 mg kg'1, established by the Romanian Legislation, while the median concentration was 0.70 mg kg'1, bellow the guideline values, but higher than the normal values for soil and the mean or median concentration in soils from other cities all over the world. In the perennial plants, the median concentration was 0.22 mg kg'1, value that exceed the maximum level of Hg (0.10 mg kg'1) established by European Directive 2002/32/EC for animal feed in order to prevent its transfer and further accumulation in the higher levels of food chain. Poor correlations were found between Hg and other elements such as As, Cd, Cu, Pb and Zn known as pollutants resulted from non-ferrous smelting activities, probably due to the different physicochemical properties of Hg that lead to a different dispersion patter compared to other metals emitted by the two smelters

ASSESSMENT OF Pb, Cd, Cu AND Zn AVAILABILITY FOR PLANTS IN BAIA MARE MINING REGION

In order to evaluate the mobility of heavy metals in soil from Baia Mare mining region, the total, water and DTPA extractable metal contents were determined. The results showed that despite the high total metals contents and the high percentages of plant available metals only a low percent was water soluble, indicating a potential accumulation of metals in trophic chain and a potential risk for public health. Among the investigated metals, the plant available Pb and Cd species are the most severe contaminants. Significant correlations between total and DTPA extractable metals were found for Cu (r=0.510) and Pb (0.418), and also an affinity between total and water extractable metals were identified for Cu (0.366), Pb (0.502) and Zn (0.597)