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A comprehensive study of high-accuracy photoionization cross sections is carried out using the relativistic Breit-Pauli R-matrix (BPRM) method for (h?+Fe xvii → Fe xviii +e). Owing to its importance in high-temperature plasmas, the calculations cover a large energy range, particularly the myriad photoexcitation-of-core (PEC) resonances including the n=3 levels not heretofore considered. The calculations employ a close-coupling wave-function expansion of 60 levels of the core ion Fe xviii ranging over a wide energy range of nearly 900 eV between the n=2 and n=3 levels. Strong-coupling effects due to dipole transition arrays 2p5→2p4(3s,3d) manifest themselves as large PEC resonances throughout this range and enhance the effective photoionization cross sections orders of magnitude above the background. Comparisons with the erstwhile Opacity Project (OP) and other previous calculations show that the currently available cross sections considerably underestimate the bound-free cross sections. A level-identification scheme is used for spectroscopic designation of the 454 bound fine structure levels of Fe xvii, with n⩽10, l⩽9, and 0⩽J⩽8 of even and odd parities, obtained using the ab initio BPRM method (compared to 181 LS bound states in the OP work). The calculated energies are compared with those available from the National Institute for Standards and Technology database, which lists 63 levels with very good agreement. Level-specific photoionization cross sections are computed for all levels. In addition, partial cross sections for leaving the core ion Fe xvii in the ground state are also obtained. These results should be relevant to modeling of astrophysical and laboratory plasma sources requiring (i) photoionization rates, (ii) extensive nonlocal-thermodynamic-equilibrium models, (iii) total unified electron-ion recombination rates including radiative and dielectronic recombination, and (iv) plasma opacities. We particularly examine PEC and non-PEC resonance strengths and emphasize their expanded role to incorporate inner-shell excitations for improved opacities, as shown by the computed monochromatic opacity of Fe xvii. [ABSTRACT FROM AUTHOR]

Abstract: We propose a model of a capillary network in which chaotic capillary activity is crucial for efficient oxygenation of a muscle fiber. Tissue oxygenation by microcirculation is controlled by a complex pattern of opening and closing of precapillary sphincters, a phenomenon known as vasomotion. We model the individual precapillary sphincter as a non-linear oscillator that exhibits perfectly periodic vasomotion in isolation. The precapillary sphincters surrounding an active fiber are considered as a network; specific modes of interaction within this network result in complex patterns of vasomotion. In our model, efficient oxygenation of the fiber depends crucially on the mode of interaction among the vasomotions of the individual capillaries. Network interactions that lead to chaotic vasomotion are found to be essential for meeting the tissue oxygen demands precisely. Interactions that cause regular rhythmic patterns of vasomotion fail to meet oxygenation demands accurately. [Copyright &y& Elsevier]

Lithography-based integrated circuit fabrication is rapidly approaching its limit in terms of feature size. The current alternative is nanotechnology-based fabrication, which relies on self-assembly of nanotubes or nanowires. Such a process is subject to a high defect rate, which can be tolerated using carefully crafted defect tolerance techniques. This paper presents an algorithm for reconfiguration-based defect tolerance in nanotechnology switches. The algorithm offers an average switch density improvement of 50% to 100% to most recently published techniques. The algorithm is also consistent in improving the yield through minimizing false rejects as the results show over a large sample. The improvement percentage varies depending on the manufactured switch size and the desired defect-free size with the improvement in efficiency directly proportional to the size of the switch. [ABSTRACT FROM AUTHOR]