2,937 research outputs found

    Two-point motional Stark effect diagnostic for Madison Symmetric Torus

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    A high-precision spectral motional Stark effect (MSE) diagnostic provides internal magnetic field measurements for Madison Symmetric Torus (MST) plasmas. Currently, MST uses two spatial views-on the magnetic axis and on the midminor (off-axis) radius, the latter added recently. A new analysis scheme has been developed to infer both the pitch angle and the magnitude of the magnetic field from MSE spectra. Systematic errors are reduced by using atomic data from atomic data and analysis structure in the fit. Reconstructed current density and safety factor profiles are more strongly and globally constrained with the addition of the off-axis radius measurement than with the on-axis one only

    Non-home prepared foods : contribution to energy and nutrient intake of consumers living in two low-income areas in Nairobi

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    Objective: To determine the nutritional importance of non-home prepared foods for men, women and schoolchildren living in two low-income residential areas of Nairobi, and the sources of these non-home prepared foods. Design, setting and subjects: A survey was conducted in Korogocho, a slum area, and Dandora, a low-middle-income residential area. Some 241 men, 254 women and 146 children aged 9 to 14 years were included in the study. Food intake was measured using three 24-hour recalls per individual, with special attention on the sources of all foods consumed. Results: The median proportion of daily energy intake of consumers provided by non-home prepared foods ranged from 13% for schoolchildren in Korogocho to 36% for men in Dandora. The median contribution to fat intake was higher than to energy, but the contributions to iron and vitamin A intakes were lower than to energy intake. Men consumed more non-home prepared foods on weekdays than at the weekend. Intakes of energy and most nutrients were below Kenyan Recommended Daily Intakes in all groups, but similar for consumers and non-consumers. In Korogocho, street foods were the main source of non-home prepared foods. In Dandora, both kiosks and street foods were major sources. Conclusions: Non-home prepared foods are an important source of energy and nutients for men, women and schoolchildren in Nairobi. In Korogocho, street foods, and in Dandora, both kiosks and street foods are the main sources of non-home prepared foods. The adequacy of energy and nutrient intakes does not differ between consumers and non-consumers of non-home prepared foods

    Nonmonotonic Trust Management for P2P Applications

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    Community decisions about access control in virtual communities are non-monotonic in nature. This means that they cannot be expressed in current, monotonic trust management languages such as the family of Role Based Trust Management languages (RT). To solve this problem we propose RT-, which adds a restricted form of negation to the standard RT language, thus admitting a controlled form of non-monotonicity. The semantics of RT- is discussed and presented in terms of the well-founded semantics for Logic Programs. Finally we discuss how chain discovery can be accomplished for RT-.Comment: This paper appears in the proceedings of the 1st International Workshop on Security and Trust Management (STM 2005). To appear in ENTC

    Magnetic field influence on the proximity effect in semiconductor - superconductor hybrid structures and their thermal conductance

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    We show that a magnetic field can influnce the proximity effect in NS junctions via diamagnetic screening current flowing in the superconductor. Using ballistic quasi-one-dimensional (Q1D) electron channels as an example, we show that the supercurrent flow shifts the proximity-induced minigap in the excitation spectrum of a Q1D system from the Fermi level to higher quasiparticle energies. Thermal conductance of a Q1D channel (normalized by that of a normal Q1D ballistic system) is predicted to manifest such a spectral feature as a nonmonotonic behavior at temperatures corresponding to the energy of excitation into the gapful part of the spectrum.Comment: 5 pages, 3 figures, revised version with a new titl

    Radiolysis of NaCl at high and low temperatures: development of size distribution of bubbles and colloids

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    New experimental results are presented on low temperature irradiation (18 °C) of rock-salt samples which had been exposed to initial doses up to 320 GRad at 100 °C. Differential scanning calorimetry (DSC) shows that the latent heat of melting (LHM) of sodium colloids decreases during subsequent low-temperature irradiation, whereas the stored energy (SE) increases slowly, indicating that the process of radiolysis continues. The decrease of the LHM is due to dissolution of large colloids, because the intensities of the melting peaks decrease during the second stage irradiation at low temperature. The model is formulated to describe the nucleation kinetics and the evolution of the size distribution of chlorine precipitates and sodium colloids in NaCl under high dose irradiation. It is shown that the mechanism of dissolution of large Na colloids during low temperature irradiation can be related to melting of sodium colloids.
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