Rotational Doppler beaming in eclipsing binaries

In eclipsing binaries the stellar rotation of the two components will cause a rotational Doppler beaming during eclipse ingress and egress when only part of the eclipsed component is covered. For eclipsing binaries with fast spinning components this photometric analogue of the well-known spectroscopic Rossiter-McLaughlin effect can exceed the strength of the orbital effect. Example light curves are shown for a detached double white dwarf binary, a massive O-star binary and a transiting exoplanet case, similar to WASP-33b. Inclusion of the rotational Doppler beaming in eclipsing systems is a prerequisite for deriving the correct stellar parameters from fitting high quality photometric light curves and can be used to determine stellar obliquities as well as e.g. an independent measure of the rotational velocity in those systems that may be expected to be fully synchronized.Comment: 5 pages, 3 figures, accepted by the Astrophysical Journal, Part

Dynamic flow phenomena in a foam application unit

If, during the operation of a foam application unit, a change in the foam production is introduced, the change in the flow becomes noticeable at the point of application onlyafter a certain response delay time. During the operation of the unit it is necessary to take this response delay into consideration. By varying the flow of foam in the application unit, the mass content of foam in the unit is changed as a result of the changed pressure inside the unit. The response delay has been mathematically derived for the flow of agiven type of foam through pipes, as well as through a foam printing unit as a whole. A deviation in the yield of foam on the substrate can be avoided by considering the respons delay caused by a change in the foam production process

The economically optimal design of heat exchangers

A new method to design heat exchangers is proposed, which is based on the process description by Kays and London and lends itself very well to optimization.\ud The method is described by applying it to the economic optimization of a counter-current exchanger, the extension to other flow configurations being selfexplanatory.\u

Absorption and rheological phenomena during foam application on textiles

A simple rheological model has been used to describe foam flow through moving textile assemblies. The validity of this model was tested, and the nature and the relative magnitude of deviations from the model evaluated for several different substrates. Neglecting foam degeneration during transport, the model was found to represent a valuable means of evaluating some rheological and geometrical deviations. The model can be used in a semi-quantitative way to describe absorbency during foam application. Liquid absorption experiments done off-line, absorption during foam application and some earlier results could be described using different theoretical approaches. Some rheological anomalies have been discussed

Measuring Ethno-Linguistic Affinity between Nations

Research on ethno-linguistic ties has so far mostly focused on domestic measures of ethno-linguistic heterogeneity. Little attention has been given to the possibility that ethno-linguistic relations between countries may affect out- comes, particularly in a spatial econometric context. In this paper, I propose a way of measuring Ethno-Linguistic Affinity between nations. This new index measures the degree of similarity two randomly drawn individuals from two different populations can be expected to display. I show that this measure has a number of attractive theoretical characteristics, which make it particularly useful and continue to actually construct such a measure for all countries in Africa. Finally, using this measure of Ethno-Linguistic Affinity, I show that civil conflict in Africa is likely to spill over between contiguous ethno-linguistically similar countries.Ethno-Linguistic heterogeneity, spatial econometrics, conflict, Africa

A fast ethanol assay to detect seed deterioration

The most common way to test seed quality is to use a simple and reliable but time- and space-consuming germination test. In this paper we present a fast and simple method to analyse cabbage seed deterioration by measuring ethanol production from partially imbibed seeds. The method uses a modified breath analyser and is simple compared to gas chromatographic or enzymatic procedures. A modified method using elevated temperatures (40°C instead of 20°C) shortened the assay time and improved its sensitivity. The analysis showed an inverse correlation between ethanol production and seed quality (e.g. the final percentages or speed of germination and the number of normal seedlings). The increase in ethanol production was observed when cabbage seeds were deteriorated by storage under ambient conditions or hot water treatments, both of which reduced the number of normal seedlings. Premature seeds produced more ethanol upon imbibition than mature seeds. Ethanol production occurred simultaneously with oxygen consumption, indicating that lack of oxygen is not the major trigger for ethanol production

Protein molecular weight computation from sedimentation velocity data

In ultracentrifugation, the concentration gradient of mono-disperse samples obtained by sedimentation velocity experiments is described by Gehatia's equation which holds several parameters including the sedimentation and diffusion constants. Once these two constants are known, the molecular weight follows from the Svedberg equation. A least squares method has been developed to derive the transport constants from the refractive index gradient curves. The method employs a mathematical model based on Gehatia's theory. A main feature of the model is the application of two sets of intermediate parameters via which the transport coefficients are much casier calculated than along a direct way. Furthermore some difficult to observe quantities cancel out. The square residues are minimised numerically. The potential errors introduced by this numerical minimalisation are shown to be unimportant compared to the unavoidable experimental errors

Mass transfer, fluid flow and membrane properties in flat and corrugated plate hyperfiltration modules

Concentration polarisation, decreasing the efficiency in membrane separation processes, can be reduced by increasing mass transfer between membrane surface and bulk of the feed stream. Analogous to techniques used in plate heat exchangers efforts have been made to enhance mass transfer in a plate hyperfiltration module by using a corrugated membrane in stead of a flat one. The corrugations are pressed into an originally flat membrane. These corrugations do not only have an influence on the mass transfer, but also on such membrane properties as salt and water permeability. Corrugations enhance mass transfer in a more effective way than increase of flow rate does.\ud \ud The effect of the corrugations on membrane properties shows a large spread. For corrugated membranes prepared by our group, flux increases of 100% at almost the same or even slightly higher retentions have been obtained