580 research outputs found
Majorana-Oppenheimer approach to Maxwell electrodynamics in Riemannian space-time
The Riemann -- Silberstein -- Majorana -- Oppengeimer approach to the Maxwell
electrodynamics in presence of electrical sources and arbitrary media is
investigated within the matrix formalism. The symmetry of the matrix Maxwell
equation under transformations of the complex rotation group SO(3.C) is
demonstrated explicitly. In vacuum case, the matrix form includes four real matrices . In presence of media matrix form requires two
sets of matrices, and -- simple and
symmetrical realization of which is given. Relation of and
to the Dirac matrices in spinor basis is found. Minkowski
constitutive relations in case of any linear media are given in a short
algebraic form based on the use of complex 3-vector fields and complex
orthogonal rotations from SO(3.C) group. The matrix complex formulation in the
Esposito's form, based on the use of two electromagnetic 4-vector, is studied
and discussed. Extension of the 3-vector complex matrix formalism to arbitrary
Riemannian space-time in accordance with tetrad method by
Tetrode-Weyl-Fock-Ivanenko is performed.Comment: 32pages. Proccedings of the 14th Conference-School "Foundation &
Advances in Nonlinear Science", Minsk, September 22-25, 2008. P. 20-49; ed.
V.I. Kuvshinov, G.G. Krylov, Minsk, 200
Characterisation of ashes from waste biomass power plants and phosphorus recovery
Biowastes, such as meat and bone meal (MBM), and poultry litter (PL), are used as energy sources for industrial combustion in the UK. However, the biomass ashes remaining after combustion, which contain nutrients such as phosphorus, are landfilled rather than utilised. To promote their utilisation, biomass ashes from industries were characterised in terms of their elemental and mineral compositions, phosphorus extractability, and pH-dependent leachability. These ashes were highly alkaline (pH as high as 13), and rich in calcium and phosphorus. The P bio-availabilities in the ash evaluated by Olsen\u27s extraction were low. Hydroxyapatite and potassium sodium calcium phosphate were identified by X-ray powder diffraction (XRD) as the major phases in the MBM and PL ashes, respectively. The leaching of P, Ca, and many other elements was pH dependent, with considerable increase in leaching below about pH 6. P recovery by acid dissolution (e.g., with H SO ) seems feasible and promising; the optimized acid consumption for ~90% P recovery could be as low as 3.2–5.3 mol H /mol P. 2 4
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