Sequential batch reactor for eucalypt kraft pulp effluent treatment with Trametes versicolor

BACKGROUND: A sequential batch reactor (SBR) was used for eucalypt kraft pulp effluent treatment with Trametes versicolor. A 2³ full factorial design and response surface methodology were applied to optimise the batch fermentation conditions. Effluent concentration, culture medium and inoculum age were the factors selected for this study in order to optimise the reduction of chemical oxygen demand (COD). RESULTS: The presence of Trametes Defined Medium (TDM) in the fermentation was required to obtain a significant COD reduction. Experiments in the batch reactor confirmed, in general, the predicted results of optimisation developed from Erlenmeyer batch assays. The T. versicolor culture remained active during 42 days of study in the SBR, providing approximately 80% of COD reduction. CONCLUSION: Trametes versicolor may be considered as very promising for the biological treatment of effluents from kraft pulp mills in an SBR system instead of the activated sludge mixed cultures traditionally used. Copyright © 2008 Society of Chemical Industry     

Influence of Reaction Parameters on the Hydrogenolysis of Hydroxymatairesinol Over Carbon Nanofibre Supported Palladium Catalysts

The density functional theory (DFT/B3LYP) calculations were applied to investigate the interaction of a Pt₆ particle with the ZSM-5 zeolite framework. The electronic structure of the metal particle is strongly affected by the interaction with basic framework oxygens and acid sites of the zeolite support. Adsorption on basic sites (E_ads = 6 kcal/mol) favors the formation of the electron enriched metal cluster. Interaction of the platinum cluster with the acid site characterized by stabilization energy of 47 kcal/mol results in oxidation of the metal particle and suppression of Brønsted acidity of the support. The hypothesis is put forward that the oxidized platinum particle can function as an active site for the alkane isomerisation on platinum supported high silica zeolites.     

Calculated and Experimental Estimation of Absorbed Mechanical Work in Deformation of Synthetic Fibres

Methods are proposed for obtaining the elastic and absorbed components of deformation and mechanical work expended in the region of a nondestructive mechanical effect from the stress-strain diagrams or by calculated prediction. The closeness of the values of the absorbed and correspondingly the elastic components obtained with the measured or predicted stress-strain diagram totally confirm the satisfactory reliability of modeling the physicomechanical properties of a fibre in the form of an integral equation in which the nonlinear-hereditary kernel analytically reflects the activating character of the mechanical effect combined with the concept of the deformation-time analogy in normalized form [5].     

Kinetics of catalytic reactions with two types of sites: nonuniform surfaces

Several aspects of heterogeneous catalytic kinetics over induced nonuniform surfaces are considered. The reaction mechanism is thought to occur through a surface collision of species, adsorbed on two distinct surface sites, which display nonuniform behavior. The expressions for rates of elementary reactions have been deduced within the framework of the surface electronic gas model, which accounts for the case of inhomogeneous surface. Equations for catalyst activity in the range of medium coverage have been derived and compared with the power-law model.     

Operation of an experimental facility for fabrication of fuel elements and fuel assemblies of the bor-60 containing vibrocompacted fuel

Translated from Atomnaya Énergiya, Vol. 67, No. 5, pp. 320–323, November, 1989.     

Magnetic-Field-Controlled 1D Photonic Crystal Based on a Periodic Bigyrotropic Structure

A theoretical study is reported of the magnetic-field-controlled optical transmission through a stack of identical bilayers in which one layer is bigyrotropic and the other is nonmagnetic and isotropic. An analytical expression for the complex transmittance is derived. The transmittance–wavelength characteristic is examined for different magnetizations and for fixed materials parameters and total number of bilayers. The magnetization dependence of the position, height, and width of the center peak is investigated. The effect is calculated of magnetization on the ellipticity of transmitted light and the angle of optical rotation.     

Use of a mathematical model in predicting the density of glass for controlling a tank furnace

Translated from Steklo i Keramika, No. 1, pp. 11–12, January, 1992.     

Control over the parameters of InAs-GaAs quantum dot arrays in the Stranski-Krastanow growth mode

The effect of the growth temperature on the density, lateral size, and height of InAs-GaAs quantum dots (QD) has been studied by transmission electron microscopy. With the growth temperature increasing from 450 to 520°C, the density and height of QDs decrease, whereas their lateral size increases; i.e., the QDs are flattened. The blue shift of the photoluminescence line indicates decreasing QD volume. The observed behavior is in agreement with the thermodynamic model of QD formation. The effect of lowering the substrate temperature immediately after the formation of QDs on the QD parameters has been studied. On lowering the temperature, the lateral size of QDs decreases and their density increases; i.e., the parameters of QD arrays tend to acquire the equilibrium parameters corresponding at the temperature to which the cooling is done. The QD height rapidly increases with cooling and may exceed the equilibrium value for a finite time of cooling, which enables fabrication of QD arrays with a prescribed ratio between height and lateral size by choosing the time of cooling.