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H. J. H. Brouwers 《Heat and Mass Transfer》1993,29(1):17-26
A film model is described for free convective heat transfer and friction in the presence of wall suction or injection. The analysis yields a thermal correction factor, which appears to be the classical (Ackermann) expression, and a novel friction correction factor, derived here for the first time. Both correction factors are applied to free convection along a vertical flat porous plate for values of the Prandtl number of 0.73, 1 and 7. Subsequently, the film theory predictions are compared with the numerical and asymptotic results of a boundary layer analysis, performed by previous investigators. On the basis of this comparison, a modified correction factor is proposed which correlates excellently with the results of the boundary layer analyses.
Ein Filmmodell für freie Konvektion an einer senkrechten porösen Platte mit Ausblasung und Absaugung
Zusammenfassung Es wird ein Filmmodell beschrieben, das für freie Konvektion den Wärmeübergang und den Reibungsbeiwert bei Wandaus- oder -einblasung zu bestimmen gestattet. Die Untersuchung liefert einen thermischen Korrekturfaktor, der mit der klassischen Ackermann-Korrektur übereinstimmt und einen neuen, hier erstmalig abgeleiteten Korrekturfaktor für den Reibungsbeiwert. Beide Korrekturfaktoren werden zur Ermittlung der freien Konvektionsströmung entlang einer senkrechten, ebenen, porösen Platte herangezogen (für Prandtl-Zahlen: 0,73-1-7). Anschließend erfolgt ein Vergleich der Voraussagen nach der Filmtheorie mit den numerisch aus einer asymptotischen Grenzschichtanalyse erhaltenen Ergebnissen früherer Autoren. Aus diesem Vergleich resultiert ein modifizierter Korrekturfaktor für den Reibungsbeiwert, der eine ausgezeichnete Korrelation mit den Ergebnissen nach der Grenzschichttheorie liefert.相似文献
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Mirjam Kretzschmar Johannes C. Jager Dick P. Reinking Gertjan van Zessen Henk Brouwers 《The Journal of mathematical sociology》2013,37(4):351-374
Survey data and a simulation model based on a stochastic pair formation process are used to construct networks of sexual contacts. We model heterosexual partnerships which can be steady or casual depending on their average duration. Transmission of an infectious disease can take place in pairs of a susceptible and an infected individual. We study networks of sexual contacts accumulated during 1 year for different types of mixing patterns. The networks are constructed on the basis of data from a survey in The Netherlands. We analyze the network structure for different mixing patterns and investigate the relationship between network structure and disease spread; furthermore we study the effect of prevention measures on the structure of the network. 相似文献
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Brouwers EE Tibben MM Pluim D Rosing H Boot H Cats A Schellens JH Beijnen JH 《Analytical and bioanalytical chemistry》2008,391(2):577-585
We present a highly sensitive method for the determination of platinum (Pt) in DNA extracts of peripheral blood mononuclear
cells (PBMCs) and tissue samples from patients treated with cisplatin. The method is based on the measurement of Pt by inductively
coupled plasma mass spectrometry (ICP-MS) and allows quantification of Pt-DNA adducts in PBMCs isolated from 10 mL blood and
1 mg tissue. The lower limit of quantification is 0.75 pg Pt or 7.5 fg Pt μg−1 DNA when using 100 μg DNA. The method proved to be accurate and precise. The results obtained using the ICP-MS method were
in good agreement with results from the alternative 32P-postlabelling assay. The ICP-MS method was, however, more sensitive and proved to be less laborious. The advantages of the
presented ICP-MS technique were demonstrated by the analysis of PBMCs, normal gastric tissue, and gastric tumour tissue of
patients treated with cisplatin. 相似文献