Nd1.9M0.1Fe12Co2B,M = Ti or Hf as a material for permanent magnets

Magnetic properties (saturation magnetizations, anisotropy fields and Curie temperatures) of the alloys of the composition Nd_1.9M_0.1Fe₁₂Co₂B, with M = Ti and Hf are presented. All of the compounds crystallize in the tetragonal Nd₂Fe₁₄B structure. With substitution of Nd by Ti or Hf, the saturation moment and Curie temperature decrease, but the anisotropy fields, H_A, are found to increase significantly. Theoretical energy products are reduced from 65 to 63 MGOe when Nd is replaced by Ti or Hf to the extent of x = 0.1.     

Gas turbine exhaust gas heat recovery at South Baghdad (Iraq) power plant

Gas turbine exhaust is usually relatively clean, especially the exhaust from natural gas turbines. The use of such gases to improve the overall thermal efficiency of a steam power plant has the advantage of reducing the cost of cleaning the equipment and reducing the maintenance costs of the heat recovery equipment used in the application.In this paper, two proposals for recovering the waste energy of the exhaust gases from a gas turbine unit, fuelled by natural gas at south Baghdad Power Plant (Iraq) are discussed. The proposals cover improvements to the thermal efficiency of a steam power plant installed near the gas turbine unit. The first proposal is to use the exhaust gases to preheat the feed water at four feed water heaters, in order to increase the power output. This arises because of the savings in the amount of steam extracted at a different level used for preheating the feed water line. The second proposal is to use the thermal energy in the exhaust gases to reheat the extracted stream, at five points at a high thermal potential, to increase the thermal gain at the preheating feed water line. This avoids the complexity associated with rejection of the extracted steam. The first roposal shows that a 1.22–14.9% saving in fuel consumption is achievable and the overall thermal efficiency of the steam power plant becomes 29–34% (at different gas turbine plant loads). The second proposal shows that a 2.3–7.35% saving in fuel consumption can be attained and the corresponding thermal efficiency will be 30.3–32%.     

The thermomechanical method for evaluation of the crosslinking parameters in irradiated polyethylene

The measurement of penetration deformation above the melting point was used for determination of viscoelastic parameters, compliance and retardation time, in γ-irradiated polyethylene systems. The time-dependent penetration deformation was followed over two creep and recovery cycles. The five-element mechanical model equation was used for calculation of amplitudes, time factors and remained deformations. The modulus of elasticity, derived from the equilibrium compliance was used to obtain M_c, the value of the average molecular weight between crosslinks.     

A new approach to Burger's equation

A new approach to Burger's equation is proposed using the decomposition method, eliminating smallness assumptions or linearization.     

Best piecewise constant approximation of a function of single variable

This paper is concerned with the best piecewise constant approximation of a function f of single variable. Polynomial time algorithms are derived by using shortest path and dynamic programming techniques. Several applications of this class of problems will be briefly touched upon.     

Fusion oscillations for 16O with 12C

We explain qualitatively the oscillations seen in the total fusion excitation function of ¹⁶O on ¹²C by using an optical model potential containing a parity dependence which accounts for elastic α-particle transfer. We show that it is possible to achieve this while simultaneously obtaining a reasonable fit to the elastic angular distributions. In particular the anomalous large angle scattering is consistent with the parity dependence required to fit the fusion oscillations.     

A possible quark mechanism for the saturation of nuclear matter

A nuclear matter saturation mechanism based on the quark structure of the nucleon is proposed. Nuclear matter is described by nucleons and mesons but the meson field modifies the internal quark motion and this induces a saturation mechanism. Its possible relevance for nuclear physics is studied in a schematic model where it is the only active mechanism. Though caricatural, this model provides a rather satisfactory interpretation of the nuclear matter properties.     

Restoration of 2π0 inclusive distribution from observed 2γ data

Here a formula is derived to restore the 2π⁰ effective mass distribution from the observed 2γ one. The method is applied on bubble chamber events of moderate statistics, as a preliminary survey, and gives an exponential asymptotics in the relative rapidity.