Innovationen in der Modellierung von Sedimenttransport und Morphodynamik basierend auf dem Simulationsmodell iSed

This work presents recent developments in the simulation of sediment transport and morphodynamics on the basis of the simulation model iSed, which was developed at the University of Natural Resources and Life Sciences, Vienna. The computer model is coupled with external hydrodynamic models to obtain the flow field as the basis for the simulation of sediment transport processes. The paper first defines the physical processes that must be captured by a model as well as their underlying equations. Thereafter the general model validation based on data from a laboratory flume with a 180° bend under unsteady flow conditions is shown, a model that has also been applied to study a section of the Danube River east of Vienna. The calculated bedload transport rates as well as their spatio-temporal variability showed a very good agreement with measurement data. Moreover the model allowed for the first time a successful simulation of the bed forms present in the Danube as well as their downstream movement. In order to achieve this, non-uniform calculations including grain sorting, as well as detailed field measurement data for the model setup and calibration, constitute essential prerequisites.     

Innovative Methoden zum Geschiebemonitoring am Beispiel der Donau

In this article, new and innovative methods for bedload transport monitoring and their application in the context of a restoration project on the Danube River are described. Using an adapted basket sampler, a first comprehensive monitoring campaign for measuring bedload transport on the Danube was conducted and the temporal and spatial variability was shown. The development of a methodology for tracing artificial pebbles made it possible to track 40 pebble tracers of three different sizes on the Danube over the course of an entire year. Combining the two methods it could be determined that bedload already moves at low flow conditions and that bedload transport only increases slightly or even remains constant after reaching bank-full discharge. The tracer study identified size-selective transport ?C larger sizes were moving less often and over shorter distances than smaller sizes ?C with a mean transport distance of 3?km per year for the current bed material at Bad Deutsch-Altenburg. Detailed bathymetry and the analysis of the layer succession of the riverbed using the Freeze Core methodology complemented the other insights into the processes of sediment transport on the Danube River. These methods successfully characterized gravel sheets and allowed us to make predictive statements about bed armoring. We were also able to confirm a mean bed degradation of 2?cm per year using a combination of methods.     

Effect of sieved fractionation on the physical,flow and hydration properties of Boscia senegalensis Lam., Dichostachys glomerata Forssk. and Hibiscus sabdariffa L. powders

Food Science and Biotechnology - This study aimed at evaluating the effect of successive grinding and sieving processes on the physicochemical properties of powders obtained from Boscia...     

Nouveau type structural dans la chimie des phosphures : Le compose ternaire Ni20Zr6P13. Preparation,structure et proprietes

Two new compounds Ni₁₂Zr₂P₇ and Ni₂₀Zr₆P₁₃ were synthesized in the NiZrP system by reacting the constituent elements. Ni₁₂Zr₂P₇ is of the Fe₁₂Zr₂P₇-type while Ni₂₀Zr₆P₁₃ appears as a new structural type in the chemistry of transition metal phosphides. Its unit cell is hexagonal with space group P6̄ and contains one formula unit. The X-ray structure was studied from three-dimensional single-crystal counter data and was refined down to R = 0.040 for 221 independent reflections. The structure of Ni₂₀Zr₆P₁₃ can be described as built up by two groups of three phosphorus trigonal prisms occupied by the zirconium atoms. In each group, the |ZrP₆| prisms are linked together by common edges in order to generate triangular phosphorus sites occupied by nickel atoms. In addition, nickel atoms are also in tetrahedral and square-planar pyramidal phosphorus sites. A comparative study with the Fe₂P- and Co₄Hf₂P₃-type structures having the same metal/non metal ratio as in Ni₁₂Zr₂P₇ and Ni₂₀Zr₆P₁₃ is also discussed. A nearly temperature independent paramagetism and a metallic conduction deducted from magnetic and electrical measurements exhibit the metallic behavior for these new compounds.     

Isolation,characterization, and quantitative analysis of Microviridin J,a new Microcystis metabolite toxic to Daphnia

This paper describes the purification and characterization of microviridin J, a newly discovered metabolite of Microcystis that causes a lethal molting disruption in Daphnia spp., upon ingestion of living cyanobacterial cells. Microviridin J consists of an acetylated chain of 13 amino acids arranged in three rings and two side chains. Unlike other known isoforms of microviridin, microviridin J contains arginine that imparts a unique solution conformation characterized by proximal hydrophobic interactions between Arg and other regions of the molecule. This eventually results in the formation and stabilization of an additional ring system. Microviridin J potently inhibits porcine trypsin, bovine chymotrypsin, and daphnid trypsin-like proteases. The activity against trypsin is most likely due to Arg and its distinctive conformational interactions. Overall, the data presented for microviridin J emphasize once again the ability of cyanobacteria to produce numerous and potent environmental toxins.     

A web-based platform for virtual screening

A fully integrated, web-based, virtual screening platform has been developed to allow rapid virtual screening of large numbers of compounds. ORACLE is used to store information at all stages of the process. The system includes a large database of historical compounds from high throughput screenings (HTS) chemical suppliers, ATLAS, containing over 3.1 million unique compounds with their associated physiochemical properties (ClogP, MW, etc.). The database can be screened using a web-based interface to produce compound subsets for virtual screening or virtual library (VL) enumeration. In order to carry out the latter task within ORACLE a reaction data cartridge has been developed. Virtual libraries can be enumerated rapidly using the web-based interface to the cartridge. The compound subsets can be seamlessly submitted for virtual screening experiments, and the results can be viewed via another web-based interface allowing ad hoc querying of the virtual screening data stored in ORACLE.     

Novel lipidic enaminones from a C18 keto-allenic ester

Primary amines (ammonia, methyl, propyl, octyl, octadecyl, phenyl, benzyl, phenethyl) including methyl esters of amino acids (glycine, dl-alanine, l-valine, l-leucine, L-tyrosine, and l-methionine), and secondary amines (dimethyl, diethyl, dipropyl, diisopropyl, dioctyl, and diphenyl) attack regiospecifically the central carbon atom of the allene system of methyl 12-keto-9,10-octadecadienoate (1) to give the corresponding lipidic enaminone derivatives (2–21) with an average yield of 77%. The E- and Z-configuration of the enaminone system of these novel lipid derivatives was confirmed by infrared and nuclear magnetic resonance spectroscopic techniques. Primary amines furnished Z-enaminones, while secondary amines gave E-enaminones.     

Synthesis of phenyl substituted C18 furanoid fatty esters

Methyl 9,12-epoxy-10-phenyl-9,11-octadecadienoate was prepared by acid catalyzed cyclization of methyl 9,12-dioxo-10-phenyloctadecanoate, which was derived from the oxidation of methyl 9-hydroxy-12-oxo-10-phenyloctadecanoate. The latter was exclusively obtained from methylcis-9,10-epoxy-12-oxooctadecanoate with phenyllithium in the presence of copper (I) bromide. A mixture of positional isomers, methyl 9,12-epoxy-10(11)-phenyl-9,11-octadecadienoates, was also prepared by another route. The spectroscopic properties of the various intermediates and products were studied. The positional isomers of the phenyl substituted furanoid fatty esters were characterized by¹³C nuclear magnetic resonance spectrometry.     

A theory of reading: From eye fixations to comprehension.

Presents a model of reading comprehension that accounts for the allocation of eye fixations of 14 college students reading scientific passages. The model deals with processing at the level of words, clauses, and text units. Readers made longer pauses at points where processing loads were greater. Greater loads occurred while readers were accessing infrequent words, integrating information from important clauses, and making inferences at the ends of sentences. The model accounts for the gaze duration on each word of text as a function of the involvement of the various levels of processing. The model is embedded in a theoretical framework capable of accommodating the flexibility of reading. (70 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Versatile Flat-Deposit Impactor-Type Aerosol Collector Part 1: Design and Qualitative Study

Cascade impactors provide an efficient method for sampling aerosols according to their size, grossly between 0.1 mu m and a few tens of microns in diameter. We have designed such an apparatus, with rotatable substrate plates and radially aligned rectangular orifices. The nominal cutpoint diameters are, respec tively, for stages 1-7 of the collector: 10, 5, 2, 1, 0.5, 0.25, and 0.1 mu m aed for an airflow of 10/L min. The sampler has an auxiliary set of orifice plates for operation at 20/L min giving the same cutpoint characteristics. Annular deposits are obtained following complete rotation of the collecting substrates. The airflow is controlled with a critical orifice at the last stage. A calculation program was written for a rectangular orifice impactor in order to determine the cutpoints in different conditions. The constant exit pressure mode of operation appears to be the best way to minimize fluctuations of the effective cutpoints against the varying conditions of ambient temperature and pressure. The SPAL sampler has proven satisfactory with respect to manipulations required, maintenance, and results delivered.