The Uniqueness of AF Diagonals in Regular Limit Algebras

Necessary and sufficient conditions are obtained for the uniqueness of standard regular AF maximal abelian self-adjoint algebras in regular limit algebras up to approximate inner unitary equivalence.     

Iterative solution schemes for quadratic DRM‐MD

The aim of this work is to find the most suitable iterative technique to solve linear systems of equations arising from the dual reciprocity method in multidomains (DRM‐MD). In this article, the surface variables of the governing equations and the shape functions of the boundary elements are quadratic functions, and for the dual reciprocity approximation the radial basis function (RBF) used is the augmented thin plate spline. A series of tests are carried out studying efficiency and accuracy of different Krylov iterative solvers, every one assessed with several preconditioners. The results are related to intrinsic properties of the linear systems such as condition numbers, sparsity patterns, singular values, and eigenvalues. Besides, the performance of the selected iterative solvers is studied in relation with the subdivision of the domain, taking into account total number of nodes of the whole mesh, number of internal nodes per subdomain, as well as different aspect ratios of the mesh grids. As a result, performances of different refining schemes are considered. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2008     

PARTICULATE CONCENTRATION ENRICHMENT OF PRIMARY AIR IN PULVERIZED COAL BOILERS

Particulate concentration enrichment (PCE) of primary air favors flame ignition and stabilization, and the reduction of NOx emission in pulverized coal combustion. The methods used for PCE are summarized in five categories:Cyclone PCE, Elbow PCE, Blunt-body PCE, Hydrodynamic PCE and Swirling PCE. Practice of each PCE method is illustrated with typical burners and the associated pros and cons are discussed. It is found that the same principle prevails in all PCE methods, that is, due to inertial difference, solid particles preferentially decelerate and separate from the gas stream when the main flow deviates in flow orientation. From analysis of various P-C burners, PCE design is deemed to yet comprise “rule of thumb” practice. Some discussions regarding PCE application are given.     

Reduction of viscous flows having orthogonal magnetic and velocity field distributions

Summary Certain steady magnetohydrodynamic flows of a viscous incompressible fluid, in which the magnetic field is everywhere orthogonal to the velocity field, are related to viscous compressible flows having zero magnetic field. Examples are given to illustrate this relationship. Other linked magnetic and non-magnetic flows can be found using similar processes.