488 research outputs found

    Majorana-Oppenheimer approach to Maxwell electrodynamics in Riemannian space-time

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    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 4×44 \times 4 matrices αb\alpha^{b}. In presence of media matrix form requires two sets of 4×44 \times 4 matrices, αb\alpha^{b} and βb\beta^{b} -- simple and symmetrical realization of which is given. Relation of αb\alpha^{b} and βb\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

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    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

    THE EFFECT OF SURFACTANTS ON SUPERCONFORMAL DEPOSITION OF ELECTROLESS COMPOSITES IN NANOSCALE PATTERNS

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    Electroless plating of metal composites has been proposed as a promising method for metallization of high aspect ratio trenches for micro- and nanoelectronics and microelectromechanical systems application. Deposition of Ag(W) electroless films was performed from ammoniate silver solution to fill deep damascene trenches. Polyethylene glycol (PEG) with molecular weight of 400, 1500 and 6000, RE-610 and Triton X-100 were studied as an additives in the plating bath for superconformal deposition. The deposition rate, resistivity, grain size and the trench filling behaviour were studied as a function of the additives concentration and deposition temperature using Scanning Electron Microscopy (SEM) cross section study. The PEG with molecular mass about 1500 was found to provide superconformal Ag(W) electroless growth in nanometre wide trenches
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