Volatile organic compound profiles of yoghurt produced from cow's milk with different somatic cell counts

The present study aimed to investigate the effect of somatic cell count (SCC) of raw cow's milk on the volatile organic compound (VOC) profiles of yoghurt. Test yoghurt samples were produced from three batches of cow's milk with low, medium and high SCC, respectively. The VOCs were determined by gas chromatography–mass spectrometry (GC–MS) analysis. A lower diacetyl and acetoin content and a higher content of 2‐heptanone, and butanoic and hexanoic acids were established in the yoghurt samples from batches with high SCC of above 1 000 000 cells/cm³. The increased SCC of cow's milk had a negative effect on the volatile organic compound profiles of yoghurt.     

Yield of products from catalytic cracking of vacuum gasoils

In catalytic cracking of vacuum gasoils, the yields of products are correlated with their hydrogen content. A correlation that allows predicting the yields of products of this process was elaborated based on the results of cracking of 11 gasoils of different origin and data on their density, refractive index, and 50% distillation temperature. However, it is not possible to predict the octane number of the naphtha obtained in cracking with the group hydrocarbon composition of the feedstock. __________ Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 4, pp. 31–34, July–August, 2007.     

Dependence of Fluid Catalytic Cracking Unit Performance on H-Oil Severity,Catalyst Activity,and Coke Selectivity

The effect of the quality of ebullated bed vacuum residue H-Oil hydrocracking gas oils cracked in a commercial fluid catalytic cracking unit (FCCU) on its performance was studied. Six different catalysts were employed in this study. Four catalysts were tested in a commercial FCCU, and two in a laboratory FCCU. An increase of the H-Oil hydrocracker reaction temperature was associated with a decrease in the K_W factor of the H-Oil gas oils. The diminished K_W factor of H-Oil gas oils resulted in lower FCCU conversion and higher regenerator temperatures. The FCC conversion at maximum gasoline yield is best predicted by the feed K_W factor. The higher-activity, higher-Δcoke catalyst is unfavorable for FCCU performance because the excessive regenerator temperature excursions require reduction of the throughput.     

Analysis of the Flow of Rarefied Gas Through a Layer of a Porous Body on the Basis of Direct Numerical Solution of the Kinetic Boltzmann Equation

The problem of the flow of rarefied gas through a layer of a porous body, which is replaced by a homogeneous system of immobile spherical particles, is solved on the basis of the method of direct numerical solution of the kinetic Boltzmann equation. The effect of the spherical particles on the gas molecules is described as a kind of boundary condition distributed in space. Dependences of the density, temperature, and velocity on the coordinate in physical space are obtained; cross sections of the distribution function of the gas molecules by velocities are presented.     

Recondensation in the Presence of a Noncondensable Component

Flows of two-component mixtures with vapor condensation on cooled surfaces are analyzed by the methods of molecular-kinetic theory. The mixture contains a noncondensable component whose average density remains constant in the region under study. The influence of the gas on the process of recondensation of the vapor and the interaction of the components of the mixture in the cases of equal and different molecular weights are studied. The problems posed are investigated using the method of direct numerical solution of the kinetic Boltzmann equation modified for the mixture of gases. Special emphasis is placed on compution of direct and cross collision integrals. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 78, No. 4, pp. 15–21, July–August, 2005.     

Effect of nitrogen-containing compounds in catalytic feedstock on the composition of gasoline

Hydrotreated vacuum gasoil from straight-run distillation of a Russian export mixture (GRES) and the same gasoil after treatment with sulfuric acid (OGRES) so that nitrogen-containing compounds were totally removed and the hydrocarbon composition was almost unchanged were investigated as catalytic feedstock. Cracking was conducted on a MAT laboratory setup with different catalyst and feedstock ratios, constant reactor temperature of 527°C, and feedstock contact time with catalyst of 30 sec. Elimination of nitrogen-containing compounds from GRES increased the yield of cyclic hydrocarbons in the naphtha cut with lower aromatization and decreased the yield of macromolecular aliphatic hydrocarbons with lower olefination. In the absence of basic nitrogen, the activity and selectivity of the catalyst for the naphtha and light cyclic petroleum products increased. The naphtha obtained from OGRES, in comparison to the naphtha obtained from GRES, contains more cycloalkanes and less alkanes and alkenes and has lower research and motor octane numbers.     

Interaction between potassium-graphite intercalation compounds and alcohols or diols

The interaction is investigated between potassium-graphite intercalation compounds (IC) and alcohols or diols in solvating and nonsolvating solvents. The influence of the type of the alcohol or diol, the nature of the solvent and the type of IC on the amount of potassium extracted from the IC as an alcoholate is studied. It is established that the structure and properties of the IC undergo significant changes. C_x (K)_y (RO⁻K⁺)_y, compounds are probably formed in cyclohexane and C_x(K)_y(RO⁻¹K⁺)_y′ (solvent)_y′′ compounds, respectively in benzene, tetrahydrofuran or dimethoxyethane. The compounds formed are not able to reduce biphenyl and naphthalene, but they do reduce aromatic ketones and nitriles to the corresponding metal adducts.