Physics Potential of a Radio Surface Array at the South Pole (ARENA 2018)

A surface array of radio antennas will enhance the performance of the IceTop array and enable new, complementary science goals. First, the accuracy for cosmic-ray air showers will be increased since the radio array provides a calorimetric measurement of the electromagnetic component and is sensitive to the position of the shower maximum. This enhanced accuracy can be used to better measure the mass composition, to search for possible mass-dependent anisotropies in the arrival directions of cosmic rays, and for more thorough tests of hadronic interaction models. Second, the sensitivity of the radio array to inclined showers will increase the sky coverage for cosmic-ray measurements. Third, the radio array can be used to search for PeV photons from the Galactic Center. Since IceTop is planned to be enhanced by a scintillator array in the near future, a radio extension sharing the same infrastructure can be installed with minimal additional effort and excellent scientific prospects. The combination of ice-Cherenkov, scintillation, and radio detectors at IceCube will provide unprecedented accuracy for the study of highenergy Galactic cosmic rays.Comment: Proceedings of 8th ARENA 2018, to appear in EPJ Wo

Study of high temperature bearing materials

Experimental investigation identifies materials suitable for use in potassium lubricated turbo-generator journal bearing and shaft applications at high temperatures. Attention is given to nonrefractory metals and alloys, refractory metals and alloys, Fe-Ni-Co bonded carbides, refractory compounds, and refractory metal bonded carbides

The Influence of Reflective Mulches and Lettuce Types on the Incidence of Aster Yellows and Abundance of its Vector, \u3ci\u3eMacrosteles Fascifrons\u3c/i\u3e (Homoptera: Cicadelidae), in Minnesota

Five commercial lettuce cultivars representing different genetic types were grown through aluminum-coated paper, through black polyethylene film, and on bare soil. For each variety, the aluminum mulch reduced the numbers of Macrosteles fascifrons (St~l), reduced the incidence of aster yellows, and increased yields when compared to uncovered controls. The head lettuce cultivar \u27Minetto\u27 was most susceptible on unmulched plots (74.3%) while the leaf cultivar \u27Grand Rapids\u27 was least susceptible (33.8%). The latter also had the greatest infestation of leafhoppers which may indicate either resistance to the aster yellows agent or shorter feeding times by the vector leafhopper. The abundance of aster leafhoppers on the romaine cultivar \u27Valmaine\u27, the butter head cultivar \u27Buttercrunch\u27, and the bibb cultivar \u27Summer Bibb\u27 was much lower than that of the other two and might explain the lower percentage of aster yellows on these types as compared with \u27Minetto\u27