Approximate solution to the natural convection heat transfer from a vertical plate

A new model for laminar natural convection heat transfer between an isothermal vertical plate to a power-law fluid is proposed. The difficulty caused by the fact that the momentum and energy equations are coupled is avoided by introducing an approximation based on the partial similarity between the velocity fields for forced and natural convections. The model proposed in this work agrees well with the available experimental data and correlations. Further, we have extended the analysis to turbulent natural convection heat transfer. The predicted turbulent heat transfer rates are in satisfactory agreement with the data and the correlations published in the literature.     

Catalytic Partial Oxidation of Biomass/Oil Mixture

Investigation was focussed to application of waste POX （partial oxidation）, e.g., meal rape in form of suspension in high boiling hydrocarbons from crude oil distillation. There is an opportunity for utilization of biomass waste resulted from fuels bio-components production. A decrease of oxygen and water steam demand in feed for POX process was observed in this variant. Catalytic effect of iron nanoparticles or nickel nitrate as catalysts in improvement of the pilot plant biomass/oil partial oxidation was investigated as well. Presence of catalyst in the feed supports formation of carbon monoxide and suppression content of methane in the gas product. Experimental data were well compared with process simulation based on eauilibrium reactor model.     

The Fedosov ∗-product in Mathematica

The computer program ‘Fecom.nb’ implementing the Fedosov ∗-product in Darboux coordinates is presented. It has been written in Mathematica 6.0 but it can be easily modified to be run in some earlier version of Mathematica. To optimize computations elements of the Weyl algebra are treated as polynomials. Several procedures which order the terms are included.

New version program summary

Program title: Fecom.nbCatalogue identifier: AEBU_v2_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEBU_v2_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 8107No. of bytes in distributed program, including test data, etc.: 42 175Distribution format: tar.gzProgramming language: Mathematica v.6.0Computer: AllOperating system: AllRAM: Sufficient for installation of MathematicaClassification: 17.16Catalogue identifier of previous version: AEBU_v1_0Journal reference of previous version: Comput. Phys. Comm. 179 (2008) 924Does the new version supersede the previous version?: YesNature of problem: Computing the ∗-product of the Weyl type in the Fedosov formalism in a Darboux chart.Solution method: Inputting the dimension of the phase space, coefficients of the symplectic connection, the range of approximation and the functions to be multiplied; computing the Abelian connection and the flat sections of the Weyl bundle representing the multiplied functions; calculating the projection of the ○-product of these flat sections on the phase space.Reasons for new version: Optimization and including the trivial cases - deformations of the 0th and the 1st order.Summary of revisions: In case we calculate the ∗-product up to the odd power hk, it is necessary to know the Abelian connection and the flat sections up to the degree 2k−1. But for the even power hk, it is sufficient to know the Abelian connection and the flat sections up to the degree 2k−2. In the new version of the program we use this observation. Now the running time of the program for even powers hk is shorter than in the previous version. The 0th and the 1st order of the deformation are trivial - the pointwise product of functions and the Poisson bracket of them respectively. But to make the program complete we added the possibility of calculating also these trivial situations. The new version of the program works then also for the maximal power of h equal 0 and 1.Running time: The test run, provided with the distribution, took approximately 2 minutes to run using Mathematica 7.0 on a Windows XP machine.     

SEDIMENTATION OF PARTICLES IN NON-NEWTONIAN FLUIDS

The influence of non-Newtonian flow behavior on sedimentation velocity of particles is investigated using an approximate solution for the motion of an assemblage of solid spheres presented previously by the authors. It is theoretically predicted that the pseudoplaslicity decreases the sedimentation velocity and its reduction is pronounced at large voidage. The present theory is discussed using the available empirical correlations.     

Einfluß des Gefügezustandes und der Gefügebeständigkeit auf die Zeitstandfestigkeit niedriglegierten vanadincarbidhaltigen Schweißgutes

Glühversuche von 5 000 h Dauer bei 600 °C, Gefügeuntersuchungen und Zeitstandversuche bei 525 bis 600 °C bis rd. 16 000 h Dauer an drei verschiedenen Schweißgutzusammensetzungen mit rd. 0,05 % C, 0,3 % Si, 0,7 % Mn, 0,6 bis 1,1 % Cr, 0,5 bis 0,95 % Mo, 0,3 % V und bis 0,5 % W. Bedeutung des Kohlenstoffgehaltes für die Ausscheidungsverfestigung durch Vanadincarbid. Einfluß der Gefügebeständigkeit in Abhängigkeit vom Molybdän- und Wolframgehalt auf die Zeitstandfestigkeit.     

Drag and mass transfer in non-newtonian flows through multi-particle systems at low reynolds numbers

An approximate solution for the motion of an assemblage of solid spheres moving through a power-law fluid at low Reynolds numbers is obtained using HapThe theoretical predictions based on Kuwabara's zero-vorticity cell model are very similar to those based on Happel's model. An approximation technique