5,673 research outputs found

    Physical and Physico - Chemical Characterization of Iron Ore Agglomerates

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    Performance of a blast furnace greatly depends on the quality of input raw materials, specifically the iron ore and its agglomerates, judged mainly through its reduction behaviour and strength property. Parameters like Reduci-bility Index (RI) and Reduction Degradation Index (RDI) are considered to be the important quality indicators for the selection of iron bearing material as blast furnace burden

    Comparisons of spectra determined using detector atoms and spatial correlation functions

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    We show how two level atoms can be used to determine the local time dependent spectrum. The method is applied to a one dimensional cavity. The spectrum obtained is compared with the mode spectrum determined using spatially filtered second order correlation functions. The spectra obtained using two level atoms give identical results with the mode spectrum. One benefit of the method is that only one time averages are needed. It is also more closely related to a realistic measurement scheme than any other definition of a time dependent spectrum.Comment: 8 pages, 8 figure

    Boundary conditions on the early Sun from ancient cosmogenic neon in meteorites

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    Isotopic analysis of neon from individual grains of the meteorites Murchison (CM) and Kapoeta (howardite) shows large enrichments of cosmogenic neon in grains with solar flare tracks. The quantity of this component is incompatible with galactic cosmic ray or solar cosmic ray irradiation under present conditions and is attributed to irradiation by energetic flares from an early active Sun. Handpicked grains from each meteorite were grouped according to the presence or absence of solar flare heavy ion tracks, and these four samples were analyzed with an ion counting noble gas mass spectrometer

    Precompaction irradiation effects: Particles from an early active sun?

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    Two recent studies have shown that solar flare irradiated grains from Murchison and Kapoeta have excess spallogenic Ne-21 compared to unirradiated grains, indicating large precompaction particle irradiation effects. The quantity of cosmogenic neon in these grains presents serious difficulties for either galactic cosmic ray or normal solar flare sources. In the first study it was suggested that the effect might be the result of exposure to an early active sun. The more recent experiment both confirms the earlier results and provides constraints on the characteristic energy spectrum on the irradiation. The first results were obtained from Murchison olivines and Kapoeta pyroxenes by mass spectrometric analysis of sets of grains selected on the basis of the presence or absence of solar flare particle tracks. In the second work plagioclase feldspar grains from Kapoeta were studied

    Evidence in meteorites for an active early Sun

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    The amounts of neon-21 found in meteorite particles indicate that the Sun experienced a period of intense solar flare activity approximately 4.5 billion years ago

    Indefinite Causal Order in a Quantum Switch

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    In quantum mechanics events can happen in no definite causal order: in practice this can be verified by measuring a causal witness, in the same way that an entanglement witness verifies entanglement. Indefinite causal order can be observed in a quantum switch, where two operations act in a quantum superposition of the two possible orders. Here we realise a photonic quantum switch, where polarisation coherently controls the order of two operations, A^\hat{A} and B^\hat{B}, on the transverse spatial mode of the photons. Our setup avoids the limitations of earlier implementations: the operations cannot be distinguished by spatial or temporal position. We show that our quantum switch has no definite causal order, by constructing a causal witness and measuring its value to be 18 standard deviations beyond the definite-order bound

    Ion-acoustic solitons in warm magnetoplasmas with super-thermal electrons

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    In this work, the phenomenon of formation of localised electrostatic waves (ESW) or soliton is considered in a warm magnetoplasma with the possibility of non-thermal electron distribution. The parameter regime considered here is relevant in case of magnetospheric plasmas. We show that deviation from a usual relaxed Maxwellian distribution of the electron population has a significant bearing in the allowed parameter regime, where these ESWs can be found. We further consider the presence of more than one electron temperature, which is inspired by recent space-based observations[key-2].Comment: 10 pages, 5 figure

    Improvement of environmental performance of integrated steel sector through process integration & optimisation measures and innovative waste management practices

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    The metallurgical and mineral processing industries are always known to be major contributors to environmental pollution. Amongst them, the iron & steel sector finds predominance simply because of the significant volume of effluents, emissions and solid wastes generated from the various process streams. Over the last decade efforts have been made to reduce cnvironmetital pollution from the integrated steel sector through various process integration and optimisation measures as well as cleaner technology development. In addition, a large number of innovations in waste management have resulted in implementation of integrated waste management plans in the steel sector as well as development of ninny value-added products. This paper takes an overview of some of these developments that have contributed significantly to improved environmental performance of the integrated steel sector in India

    Cranial integration in the fire salamander, Salamandra salamandra (Caudata: Salamandridae)

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    Phenotypic integration and modularity are concepts that represent the pattern of connectivity of morphological structures within an organism. Integration describes the coordinated variation of traits, and analyses of these relationships among traits often reveals the presence of modules, sets of traits that are highly integrated but relatively independent of other traits. Phenotypic integration and modularity have been studied at both the evolutionary and static level across a variety of clades, although most studies thus far are focused on amniotes, and especially mammals. Using a high-dimensional geometric morphometric approach, we investigated the pattern of cranial integration and modularity of the Italian fire salamander (Salamandra salamandra giglioli). We recovered a highly modular pattern, but this pattern did not support either entirely developmental or functional hypotheses of cranial organisation, possibly reflecting complex interactions amongst multiple influencing factors. We found that size had no significant effect on cranial shape, and that morphological variance of individual modules had no significant relationship with degree of within-module integration. The pattern of cranial integration in the fire salamander is similar to that previously recovered for caecilians, with highly integrated jaw suspensorium and occipital regions, suggesting possible conservation of patterns across lissamphibians
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