Detecting hydrogen-containing contaminants on metal surfaces

Spark emission spectroscopy analyzes surface contamination of metals. This technique controls the quality of surface preparations and is useful in fundamental investigations of surface properties of metals

Non-negative curvature obstructions in cohomogeneity one and the Kervaire spheres

In contrast to the homogeneous case, we show that there are compact cohomogeneity one manifolds, that do not support invariant metrics of non-negative sectional curvature. In fact we exhibit infinite families of such manifolds including the exotic Kervaire spheres. Such examples exist for any codimension of the singular orbits except for the case where both are equal to two, where existence of non-negatively curved metrics is known.Comment: 10 page

The Dynamics of Store Hour Changes and Consumption Behavior: Results of a Longitudinal Study of Consumer Attitudes toward Saturday Shopping in Germany

Americans who travel internationally are often shocked to discover retail outlets closed during weekend and evening hours in cities such as Paris, Rome and Berlin. Fortunately, based on the implicit assumption that demand clearly exists, retailers at various locations throughout the globe have increased their hours of operation. While political debate regarding a variety of issues (costs, the rights of labor, religion, etc.) often rages, there has been an implicit assumption that latent demand for longer hours of operation exists. Our study investigates through a longitudinal examination consumer perceptions of Saturday shopping in a country where such an activity was previously restricted. Specifically, we study perceptions of Saturday shopping among a sample of German college students who were raised with limited Saturday shopping hours. Data were gathered in 1996 – the year German legislation allowed expanded hours for retailers – and again in 1999, and comparisons are made. Strong differences are found between consumer attitudes towards Saturday shopping at the time of expansion and three years later, indicating the need for differentiating retail strategies in Germany and in other parts of the world that may soon be providing similar expanded retail access.Agribusiness,

Save Those Vegetables

In our effort to conserve food at home this year, the storage of vegetables is exceedingly important. Potatoes, carrots, beets, parsnips, cabbage, onions, squash, pumpkins and other vegetables can be stored successfully over winter so that they remain fresh and firm. The more vegetables that can be stored fresh, the less the family need draw upon canned, frozen and other conserved foods

Study of helium transfer technology for STICCR: Fluid management

The Space Infrared Telescope Facility (SIRTF) is a long life cryogenically cooled space based telescope for infrared astronomy from 2 to 700 microns currently under study and planned for launch in the mid 90's. SIRTF will operate as a multi-user facility, initially carrying 3 instruments at the focal plane. It will be cooled to below 2 K by superfluid liquid helium to achieve radiometric sensitivity limited only by the statistical fluctuations in the natural infrared background radiation over most of its spectral range. The lifetime of the mission will be limited by the lifetime of the liquid helium supply, and is currently baselined to be 2 years. Candidates are reviewed for a liquid management device to be used in the resupply of liquid helium, and for the selection of an appropriate candidate

Uniformly Accelerated Mirrors. Part 1: Mean Fluxes

The Davies-Fulling model describes the scattering of a massless field by a moving mirror in 1+1 dimensions. When the mirror travels under uniform acceleration, one encounters severe problems which are due to the infinite blue shift effects associated with the horizons. On one hand, the Bogoliubov coefficients are ill-defined and the total energy emitted diverges. On the other hand, the instantaneous mean flux vanishes. To obtained well-defined expressions we introduce an alternative model based on an action principle. The usefulness of this model is to allow to switch on and off the interaction at asymptotically large times. By an appropriate choice of the switching function, we obtain analytical expressions for the scattering amplitudes and the fluxes emitted by the mirror. When the coupling is constant, we recover the vanishing flux. However it is now followed by transients which inevitably become singular when the switching off is performed at late time. Our analysis reveals that the scattering amplitudes (and the Bogoliubov coefficients) should be seen as distributions and not as mere functions. Moreover, our regularized amplitudes can be put in a one to one correspondence with the transition amplitudes of an accelerated detector, thereby unifying the physics of uniformly accelerated systems. In a forthcoming article, we shall use our scattering amplitudes to analyze the quantum correlations amongst emitted particles which are also ill-defined in the Davies-Fulling model in the presence of horizons.Comment: 23 pages, 7 postscript figure

The effect of farming system on dairy cow cleanliness in the UK and implications to udder health

The cleanliness of dairy cows was assessed using a 20 point hygiene score system at different times in the year on 14 organic and 14 conventional farms in the UK. Overall, cows were dirtier during winter housing compared to summer grazing. Farming system had no effect on cow cleanliness when cows were at grass, but when housed in the winter, organic cows were more likely to be cleaner. There was a link between cow hygiene scores and milk hygiene, with herds having lower bulk tank somatic cell counts (BTSCC) tending to have cleaner cows. This relationship was strongest for the organic herds. There was no significant link between hygiene score and Bactoscan (BS) count or mastitis incidence