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 $4 \times 4$ matrices $\alpha^{b}$. In presence of media matrix form requires two sets of $4 \times 4$ matrices, $\alpha^{b}$ and $\beta^{b}$ -- simple and symmetrical realization of which is given. Relation of $\alpha^{b}$ and $\beta^{b}$ 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