A reference specimen for permeability measurements of fibrous reinforcements for RTM

The capability to simulate the flow of resin through a porous reinforcement by FE modelling has become very important for designing RTM production processes for high-performance composite parts. The key parameter in RTM flow simulations is the fibre reinforcement permeability. The measurement of this material parameter is still not standardized and many different set-ups have been proposed. Recently, a stereolithography technique was used to produce a textile-like solid specimen with anisotropic permeability, designed as a reference for calibration and comparison of permeability measurement set-ups and for validation of numerical permeability computation software. Unlike real textiles, the permeability properties of such reference specimens do not vary from test to test. Excellent repeatability of the experiments is achieved. When used for benchmarking, any discrepancy between different measurements on this specimen must be attributed to the set-up and data processing.This paper presents the first experimental measurements of the permeability of such reference specimens, obtained with a 2D central injection rig. The measured values, with principal components of the 2D permeability tensor of 2.47 ± 0.09 × 10^?9 m² and 5.44 ± 0.22 × 10^?9 m², are in good agreement with the values predicted using numerical permeability computation software. Statistics from a series of measurements using the same set-up show that the precision of the permeability identification depends on the data processing procedure. An approach which incorporates a numerical model that is also valid after the fluid reached an edge of the reinforcement performs significantly better than the approach, based on an analytical approximation, which was used before.     

A SDSS-based Ecological-economic Modelling Approach for Integrated River Basin Management on Different Scale Levels – The Project FLUMAGIS

Spatial and planning support for the implementation of the European water framework directive (WFD) requires interdisciplinary approaches for assessment, deficit analysis, and scenario investigation. To support the implementation of the WFD, the paper presents the innovative spatial decision support system (SDSS) approach from the FLUMAGIS project which is based on the integration of methods for ecological and socio-economic assessment, scale-specific modelling, knowledge processing and techniques for visualization. The project has developed an interactive tool for the assessment and (three-dimensional) visualization of the hydrological and ecological conditions in river basins and economic aspects of river basin management measures. The tool is designed to increase awareness of catchment scale hydrological and ecological issues. The paper presents the structure of the FLUMAGIS prototype and provides examples of scale-specific recommendations for management measures to improve water quality and hydrologic conditions in the Upper Ems river basin (Northwest Germany).     

Coding Schemes for Crisscross Error Patterns

This paper addresses two coding schemes which can handle emerging errors with crisscross patterns. First, a code with maximum rank distance, so-called Rank-Codes, is described and a modified Berlekamp–Massey algorithm is provided. Secondly, a Permutation Code based coding scheme for crisscross error patterns is presented. The influence of different types of noise are also discussed.

What defines success when visions compete: lessons from post-Katrina New Orleans

Visions can be valuable tools for guiding and uniting land use interests in a region with fragmented administration. What determines the strength of a vision and how can it effectively play its role? Our study tested and supplemented hypotheses on the success factors of visions. We chose a city in a rebuilding process because that represents a most intensive and pressing vision process. We interviewed local policy-makers, designers, researchers, and journalists to find out what they would spontaneously cite as a vision’s most crucial factors. We also reviewed the subsequent New Orleans recovery plans and compared our findings with hypotheses from visioning literature. The interviewees’ spontaneous answers largely confirm the key hypotheses about success from the visioning literature. However, the most frequently mentioned factors were not in the literature: a vision needs to be propagated by a powerful authority, a favourable larger political climate, and the funds to sustain the implementation process. For a vision to make a difference, it needs to be substantively relevant and persuasive but also have a favourable institutional climate to help it along.     

Stripe‐Like Pattern Formation in Airbrush‐Spray Deposition of Colloidal Polymer Film

We use the versatile technique of Grazing incidence small angle X‐ray scattering (GISAXS) to investigate the ordering of colloidal polymer films deposited on Silicon substrate by airbrush‐spray coating. A lateral ordering of the polymer colloids is highly desirable as it would open a promising route to generate laterally structured templates and scaffold for the fabrication of ultra‐high density media. The study shows a strong dependency of the film homogeneity on the number of spray cycles and a strong influence of the solvent choice on the film lateral ordering.     

Vergleichende Untersuchungen von Standard‐Klimadatensätzen (Testreferenzjahren) mit gemessenen Langzeit‐Klimadatensätzen für den Standort Kassel

Comparative study of standard sets of climate data (test reference years) with measured long‐term climate data for the location Kassel/Germany. For an inner‐city location in Kassel representative TRY (test reference year) data sets are compared with technical measurement results of long‐term climatic data especially as regards their application for the simulation of a building's thermal performance. This research study was carried out on the basis of climate measurements which were recorded over the period from 1994 to 2003 by the climate station of the building physics department at the University of Kassel. Both the analysis of the mean temperature values and that of the excess‐temperature degree hours show, that the test reference year in summer comprises considerably lower outside temperatures than the 10‐years average of the measurements. Not only the test reference standard year but also the data set of the German Meteorological Service for an extremely warm summer proved to be not representative. For winter, the standard year reflects the average measured conditions quite well. The outside temperature of the test reference year for a “cold winter”, however, lies well below the values of the coldest measuring periods in January and February. The comparison of simulation results with various sets of climatic data shows that deviations in the sets of climatic data also lead to clear differences in the computed values of temperature conditions in summer and in the heating energy requirement. The decade from 1990 to 2003, as is known, is one of the warmest decades since the beginning of weather recording. Whether the deviations described are due to this or rather to the very different topography of the reference location by comparison with the measuring station cannot be clarified on the basis of this investigation, presumably there is an interaction of both influences. The research study quantitatively shows, however, the range of error which may result from the application of reference climatic data.     

Faster isosurface ray tracing using implicit KD-trees

The visualization of high-quality isosurfaces at interactive rates is an important tool in many simulation and visualization applications. Today, isosurfaces are most often visualized by extracting a polygonal approximation that is then rendered via graphics hardware or by using a special variant of preintegrated volume rendering. However, these approaches have a number of limitations in terms of the quality of the isosurface, lack of performance for complex data sets, or supported shading models. An alternative isosurface rendering method that does not suffer from these limitations is to directly ray trace the isosurface. However, this approach has been much too slow for interactive applications unless massively parallel shared-memory supercomputers have been used. In this paper, we implement interactive isosurface ray tracing on commodity desktop PCs by building on recent advances in real-time ray tracing of polygonal scenes and using those to improve isosurface ray tracing performance as well. The high performance and scalability of our approach will be demonstrated with several practical examples, including the visualization of highly complex isosurface data sets, the interactive rendering of hybrid polygonal/isosurface scenes, including high-quality ray traced shading effects, and even interactive global illumination on isosurfaces.     

Effects of dietary olive and linseed oil on lipid composition, meat quality, sensory characteristics and muscle structure in pigs

The aim of this study was to alter the fatty acid composition of porcine tissue by accumulating essential fatty acids without adversely affecting carcass composition, muscle structure or meat eating quality. A total of 13 female and 12 castrated Pietrain×German Landrace pigs were fed a basal concentrate diet supplemented with 5% olive oil or 5% linseed oil during the growing-finishing period. Carcass composition and meat quality were not affected by the diet. Feeding linseed oil to pigs significantly increased the relative content of linolenic acid and long chain n-3 fatty acids in lipids of muscle, backfat and heart at the expense of arachidonic acid. Oleic acid was accumulated in muscle, backfat and heart lipids by feeding olive oil. The overall flavour of combined meat/backfat samples from castrates was negatively influenced by linseed oil supplementation compared to supplementation with olive oil. The oxidative stability of muscle lipids was lower in linseed oil-fed pigs compared to olive oil fed pigs. The greater cross section areas of the longissimus muscle of females were caused by an increased diameter of red, intermediate and white fibres.     

A general integral method for the determination of empirical reaction rates and parameters

A general procedure for the determination of empirical rates and kinetic parameters of irreversible, constant volume reactions is presented which is clearly superior to the conventional methods of kinetic analysis. By nonlinear regression of the integrated potential rate equation for stoichiometrically independent reactions of n the order, the empirical pre-exponential factor, activation energy, and reaction order are obtained. The regression equation relates explicitly the final concentration of the reference component not only to the time parameter of the reaction but also to the initial concentration. This includes an integral method for the determination of reaction orders in concentration. Two limiting cases are treated - the stoichiometric mixture of reactants and a mixture with one reactant in large excess. By analysis of standard Hougen-Watson rate models the dependence of empirical reaction orders on experimental conditions and simulated rate parameters is evaluated. By grouping the data into ranges of monotonous concentration change, conversion rates and rate parameters of reactions with changing volumes are calculated in a less rigorous deduction. The simplified interpretation of published experimental data is demonstated for the total oxidation of methane on Pd-catalysts and the dehydrogenation of cyclohexanol on ZnO.