144 articles for “approximation”

Research ArticleOpen accessIn the abstractDiffusion of Radioactive Materials in the AtmosphereAbdul-Wali Ajlouni, Manal Abdelsalam, Hussam Al-Rabai’ah, Abdullah M.S. AjlouniProblem statement: The dispersion of radioactive materials in the environment related to escaping of noble gases, halogens and aerosols of non-volatile radioactive materials, from the reactor containment during normal operations, or in the event of a sever reactor accident. Approach: radionuclide dispersion in the environment is demonstrated by mathematical tools which are the partial differential equations, mainly the diffusion equation. … …American Journal of Environmental Sciences, Vol. 5, Issue 1 · 28 Feb 2009 · 7,697 accessesView PDF Cite

Research ArticleOpen accessIn the abstractTopologies Induced by Relations with ApplicationsA. S. SalamaTopological structures induced by relations represents the process of extracting interesting decision rules from data. The attributes reduction and the calculation of core are the essentials to extract the decision rules. Finding the reducts, core and decision rules topologically is a new mathematical tool for discovering attribute dependencies in information systems. Problem statement: These mathematical tools employ some concepts from … …Journal of Computer Science, Vol. 4, Issue 10 · 31 Oct 2008 · 7,212 accessesView PDF Cite

Research ArticleOpen accessIn the abstractDynamic Measurement of Copper (II) Ion Adsorption in Activated Carbon Fixed Bed ColumnsTanokkorn Banjonglaiad, Eric Croiset, Peter Silveston et al.Dynamic experiments were carried out on the adsorption of copper (II) ions in a laboratory packed bed of activated carbon. Both pulse and step change inputs were used. Measurements were reproducible and replicate measurements furnished nearly identical parameters for a heterogeneous model of the activated carbon bed assuming Langmuir adsorption isotherm. The initial concentration of copper (II) ion was 3 … …American Journal of Environmental Sciences, Vol. 4, Issue 4 · 31 Aug 2008 · 6,862 accessesView PDF Cite

Research ArticleOpen accessIn the abstractSome Fast Methods for Fitting Some One-parameter Spatial ModelsR. J. MartinIt is common in geographic modelling to use a one-parameter spatial model to specify the inverse covariance matrix in terms of I-βW, for some known matrix W. Exact Gaussian maximum likelihood estimation of β requires evaluation of the determinant of the covariance matrix. For large data sets, this evaluation of the determinant can be slow and good approximations can be … …Journal of Mathematics and Statistics, Vol. 1, Issue 4 · 31 Dec 2005 · 6,066 accessesView PDF Cite