Glass-Like Heat Conduction in High-Mobility Crystalline Semiconductors

The thermal conductivity of polycrystalline semiconductors with type-I clathrate hydrate crystal structure is reported. Ge clathrates (doped with Sr and/or Eu) exhibit lattice thermal conductivities typical of amorphous materials. Remarkably, this behavior occurs in spite of the well-defined crystalline structure and relatively high electron mobility ($\sim 100 cm^2/Vs$). The dynamics of dopant ions and their interaction with the polyhedral cages of the structure are a likely source of the strong phonon scattering.Comment: 4 pages, 3 postscript figures, to be published, Phys. Rev. Let

Comparison of Positive and Negative Verbal Cueing on Muscular Endurance in College - Aged Females

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Paedophiles in the community: inter-agency conflict, news leaks and the local press

This article explores the leaking of confidential information about secret Home Office plans to house convicted paedophiles within a local community (albeit inside a prison). It argues that a politics of paedophilia has emerged in which inter-agency consensus on the issue of ‘what to do’ with high-profile sex offenders has broken down. Accordingly, the article situates newspaper ‘outing’ of paedophiles in the community in relation to vigilante journalism and leaked information from official agencies. The article then presents research findings from a case study of news events set in train following a whistle-blowing reaction by Prison Officers’ Association officials to Home Office plans. Drawing from a corpus of 10 interviews with journalists and key protagonists in the story, the article discusses both the dynamics of whistle blowing about paedophiles and also what happens after the whistle has blown

Grass Control in Corn with Accent and Beacon

The traditional method for grass control in corn is based on using herbicides applied to soil and incorporated before planting or to the soil surface after planting. This approach has been successful in controlling crabgrass, fall panicum and foxtails, but johnsongrass and shattercane control was sometimes inadequate

Cryogenic system for the mirror fusion test facility

The Mirror Fusion Test Facility (MFTF), currently being constructed at the Lawrence Livermore Laboratory, has large superconducting magnets, cryopanels, and supporting cryogenic equipment that will comprise one of the world's largest liquid helium (LHe) systems. The facility will provide mirror magnetic confinement for experimental fusion plasmas that will be approximately the same physical size as if in a conceptual fusion reactor. The cryogenic system typifies the magnitude and makeup of systems that will be used in future magnetic fusion reactors. Here we describe the LHe cryopumping and magnet systems. Principal components include a 3300 W helium refrigerator, 30,000 L LHe storage, a 1.5 MW (2000 hp) refrigerator compressor, 1100 m/sup 2/ of cryopanels, and a 420 MJ superconducting magnet system. Design features, method of operation, thermal protection, and helium recovery operations are discussed