Impact of intrinsic localized modes of atomic motion on materials properties

Recent neutron and x-ray scattering measurements show intrinsic localized modes (ILMs) in metallic uranium and ionic sodium iodide. Here, the role ILMs play in the behavior of these materials is examined. With the thermal activation of ILMs, thermal expansion is enhanced, made more anisotropic, and, at a microscopic level, becomes inhomogeneous. Interstitial diffusion, ionic conductivity, the annealing rate of radiation damage, and void growth are all influenced by ILMs. The lattice thermal conductivity is suppressed above the ILM activation temperature while no impact is observed in the electrical conductivity. This complement of transport properties suggests that ILMs could improve thermoelectric performance. Ramifications also include thermal ratcheting, a transition from brittle to ductile fracture, and possibly a phase transformation in uranium.Comment: 34 pages, 11 figure

Multichannel parametrization of \pi N scattering amplitudes and extraction of resonance parameters

We present results of a new multichannel partial-wave analysis for \pi N scattering in the c.m. energy range 1080 to 2100 MeV. This work explicitly includes \eta N and K \Lambda channels and the single pion photoproduction channel. Resonance parameters were extracted by fitting partial-wave amplitudes from all considered channels using a multichannel parametrization that is consistent with S-matrix unitarity. The resonance parameters so obtained are compared to predictions of quark models

Pacific Island food security: situation, challenges and opportunities

In recent years, there have been large and rapid increases in the prices of basic foods worldwide. Pacific island countries have not been isolated from the global food 'crisis'. This article shows that there are substantial differences in the impacts within and between Pacific island countries. To be effective and not counterproductive, policy and donor responses need to be tailored accordingly. This article recommends a combination of measures directed at mitigating the threats and empowering rural people to take advantage of the opportunities

Pupil participation in the construction of evaluation devices

July, 1943.Includes bibliographical references (pages 123-124).To view the abstract, please see the full text of the document