Finite-element simulations of hysteretic ac losses in a magnetically coated superconducting tubular wire subject to an oscillating transverse magnetic field

Numerical simulations of hysteretic ac losses in a tubular superconductor/paramagnet heterostructure subject to an oscillating transverse magnetic field are performed within the quasistatic approach, calling upon the COMSOL finite-element software package and exploiting magnetostatic-electrostatic analogues. It is shown that one-sided magnetic shielding of a thin, type-II superconducting tube by a coaxial paramagnetic support results in a slight increase of hysteretic ac losses as compared to those for a vacuum environment, when the support is placed inside; a spectacular shielding effect with a possible reduction of hysteretic ac losses by orders of magnitude, however, ensues, depending on the magnetic permeability and the amplitude of the applied magnetic field, when the support is placed outside.Comment: 7 pages, 4 figure

Earnings Manipulation and Managerial Investment Decisions: Evidence from Sponsored Pension Plans

Managers appear to manipulate firm earnings when they characterize pension assets to capital markets and alter investment decisions to justify, and capitalize on, these manipulations. We construct a measure of the sensitivity of reported earnings to the assumed long-term rate of return on pension assets. Managers are more aggressive with assumed long-term rates of return when their assumptions have a greater impact on reported earnings. Managers also increase assumed rates of return as they prepare to acquire other firms and as they exercise stock options, further confirming the opportunistic nature of these increases. Decisions about assumed rates of return, in turn, influence asset allocation within pension plans. Instrumental variables results suggest that a 25 basis point increase in the assumed rate of return is associated with a 5% increase in equity allocation. Taken together, these results suggest that earnings manipulation arising from managerial motivations influences significant managerial investment decisions.

Hydrogen production by photoelectrolytic decomposition of H2O using solar energy

Photoelectrochemical systems for the efficient decomposition of water are discussed. Semiconducting d band oxides which would yield the combination of stability, low electron affinity, and moderate band gap essential for an efficient photoanode are sought. The materials PdO and Fe-xRhxO3 appear most likely. Oxygen evolution yields may also be improved by mediation of high energy oxidizing agents, such as CO3(-). Examination of several p type semiconductors as photocathodes revealed remarkable stability for p-GaAs, and also indicated p-CdTe as a stable H2 photoelectrode. Several potentially economical schemes for photoelectrochemical decomposition of water were examined, including photoelectrochemical diodes and two stage, four photon processes