Authors:G. Boskovic, A. Zarubica, M. Kovacevic, and P. Putanov
Properties of two catalysts tailored in the laboratory conditions by sulfation of commercial Zr-hydroxide and Zr-hydroxide
of nitrate origin were compared with those of commercial SO4-Zr-hydroxide. Equally thermally treated samples in the temperature interval 500–700°C, and having the same amount of sulfur,
show different properties indicating memory effect of their solid parent materials. The catalyst obtained by sulfation of
commercial Zr-hydroxide differs in amount of residual sulfates upon calcination from other two catalysts. The instability
of sulfates in the previous case might be connected to the lowest surface area values of catalyst and the highest fraction
of monoclinic phase observed at all applied calcination temperatures.
Authors:V. Zecevic, D. Knezevic, J. Boskovic, D. Micanovic, and G. Dozet
A field experiment was conducted to investigate the effect of nitrogen fertilizer applications on some quality components of wheat. For winter wheat genotypes (Ana Morava, Vizija, L-3027 and Perla) were grown at Small Grains Research Centre Kragujevac in three years (2005–2007) at three levels of nitrogen fertilization (N
= 60 kg N ha
= 90 kg N ha
= 120 kg N ha
). Zeleny sedimentation value and wet gluten content in divergent wheat genotypes were analyzed in depending on the nitrogen nutrition and years. Nitrogen fertilization significantly increased sedimentation value and wet gluten content. The highest increasing of both traits established in N
variant when applied 120 kg ha
of nitrogen. Genotypes reacted differently to N level increasing. Cultivar Perla had the highest value of sedimentation and wet gluten content and this cultivar the best reacted to increasing N levels. Statistically significant differences for sedimentation value and wet gluten content were found among cultivars, years, N-doses and for all their interactions. The results have shown that the best quality of wheat was with nitrogen applied of 120 kg N ha
. Correlation between nitrogen applications and sedimentation value was significant (r = 0.208*), while between N-doses and wet gluten content was high significant (r = 0.290**). Sedimentation value and wet gluten content positively correlated (r = 0.783**).
Authors:E. Kiš, G. Lomić, G. Bošković, R. Marinković-Nedučin, and P. Putanov
The re-oxidation of low-pressure methanol synthesis catalyst was followed by means of DSC, with the aim of contributing to
a better understanding of the processes taking place during catalyst blanketing, stabilization and re-oxidation. The investigations
were carried out with previously hydrogen-reduced samples, and their successive re-oxidation was performed with different
oxygen contents in the oxygen/nitrogen gas mixtures. A procedure for catalyst stabilization and/or catalyst discharge is proposed.