A method for the calculation of biological film volume in a fluidized bed biological reactor

In a fluidized biological reactor, knowledge of the volume of the biological film surrounding each growth support particle is critical to the proper engineering of such reactors. A system of equations has been developed to correlate fluidized bed height with biological film volume. The predictions of the developed correlation have been compared to experimentally measured values. The comparison indicates good agreement when growth is fully developed in the reactor.     

Change Detection in Optical Aerial Images by a Multilayer Conditional Mixed Markov Model

In this paper, we propose a probabilistic model for detecting relevant changes in registered aerial image pairs taken with the time differences of several years and in different seasonal conditions. The introduced approach, called the conditional mixed Markov model, is a combination of a mixed Markov model and a conditionally independent random field of signals. The model integrates global intensity statistics with local correlation and contrast features. A global energy optimization process ensures simultaneously optimal local feature selection and smooth observation-consistent segmentation. Validation is given on real aerial image sets provided by the Hungarian Institute of Geodesy, Cartography and Remote Sensing and Google Earth.     

STRUCTURAL AND PARAMETRIC SENSITIVITY OF “UCKRON-1” TEST PROBLEM

The sensitivity of a specified tabular reactor to thermal runaway is simulated using a model for the UCKRON-1 Test Problem. Parametric sensitivity was increased by the increase of coolant temperature and by the increase of inlet temperature and pressure. Extension of the Test Problem by the water-gas shift reaction reduced the productivity and sensitivity of the reactor. Addition of the water-gas reaction represents the sensitivity for runaway to the structure of the model. These observations lead to a strategy for maximizing the methanol production within a range where thermal runaway does not occur.     

Effect of Co on the magnetism and phase stability of lithiated manganese oxides

We present first-principles calculations of the relative energies of various phases of lithiated manganese oxides with and without Co. We use the ultrasoft pseudopotential method as implemented in the Vienna ab initio simulation package (VASP). The calculations employ the local spin density approximation (LSDA) as well as the generalized gradient approximation (GGA). We consider monoclinic and rhombohedral structures in paramagnetic, ferromagnetic and antiferromagnetic (AF3) spin configurations. Spin-polarization significantly lowers the total energy in all cases. The effect of Co on the stability of these phases is discussed.     

One-dimensional modelling of the secondary clarifier-factors affecting simulation in the clarification zone and the assessment of the thickening flow dependence

This paper presents a one-dimensional (1-D) model of the secondary settling tank (SST), and the drive for model development is discussed using steady-state simulation results generated with a 2-D computational fluid dynamics (CFD) model. Concentration profiles measured in a flat-bottom circular (fbSST) that is equipped with suction-lift sludge removal, served for CFD model validation. We investigate the factors that may deteriorate the 1-D simulation performance of clarifier models, which incorporate dispersion both in terms of the effluent sludge concentration and in terms of the sludge blanket height. Furthermore, dispersion-models can account for the effect of clarifier flow conditions on thickening performance. However, correlations, found in the literature, are shown to have limited efficiency under the wide flow boundary conditions examined in this study. Optimisation of the 1-D clarifier model structure is proposed by using an overflow dependent dispersion coefficient and including a feed flow dependent reduction factor in the downward convective velocity term. Results obtained show improved simulation performance in the clarification zone and allow for an efficient flow-dependency formulation of the thickening performance.     

A study of the discharge characteristics of lead—acid batteries

A theoretical analysis of the electrolyte concentration distribution and current distribution in the porous lead dioxide electrode has been made by application of Fick's second law which was combined with approximate mass balances. The macrohomogeneous model for porous electrodes was used. The parameters in the models were determined experimentally for the lead dioxide battery plates and the special experimental cylindrical electrodes investigated. Numerical solutions for special cases are discussed. Theoretical results are in good agreement with experimental determinations. According to laser interferometry analysis the assumption of convectionless diffusion is, in practice, a good approximation in most cases.Theoretical studies of the local overpotential show that the utilizable capacity is determined by the decreasing ionic concentration of the electrolyte because the electrode reaction takes place mainly in the outer layers of the electrode, if the discharge current has a high value, e.g., full discharge time is less than 10 min.     

Electroencephalographic study on experimental brain edema induced by triethyltinsulfate (author's transl)

The electroencephalographic effects of several doses of a brain edema inducing agent, triethyltinsulfate (TET), was studied by implanted epidural electrodes in cats. The effect of TET on the central nervous system was found to have two phases: 1. a six hours' acute toxic phase following TET administration, 2. An edematic phase developing on the 2nd to the 4th day. Similarly to our earlier observations brain edema induced by TET was found to be dose-dependent, as shown by EEG-s, and their analysis performed by computation.