2,138 research outputs found

    Sediment metal-magnetic properties in urban catchments

    Get PDF
    This research project examines the application of mineral magnetic techniques to the characterisation of particulates and their sources in the urban highway environment and in stormwater runoff. A review of previous investigations into sources, levels and pathways of metals through the urban highway environment is presented. The principles upon which the mineral magnetic techniques are based and those parameters employed in this study are described. Previous environmental applications are reviewed. A representative sampling scheme was established in a small well-defined sub-catchment. Copper, Fe, Pb and Zn concentrations in highway associated sediments increased with proximity to the road centre and seasonal maxima occurred in summer. Heavy metal loadings were dominated by the sediment loadings. Strong linear relationships between the metals, Cu, Fe, Pb and Zn, and magnetic mineral concentration related parameters, X and IRM3oomT, were observed. Mineral magnetic characterisation achieved complete discrimination between highway associated sediments and roof sediments allowing the derivation of equations defining the sediment groupings. Variations in metal-magnetic properties of sediments with particle size ,were investigated. Primary source materials and particulates were analysed. Metallic and magnetic mineral parameters indicated that atmospheric and vehicle derived· particulates were probably the dominant origins of source particulates. The variation of particulate associated heavy metals in stormwater runoff at the sub-catchment is discussed. Mineral magnetic parameters characterised the majority of stormwater particulates with the roof sediment grouping. The implications of these investigations is discussed. The study was expanded to encompass the parent c~tchment. The characterisation of source sediments from land use and road types other than that· represented by the sub-catchment was carried out. Stormwater particulates collected at the main catchment'· outfall were found to be generally characterised with soil and roof sediment groupings. The further application and use of mineral magnetic parameters in similar research is discussed

    A redundant low power PCM telemeter for the orbiting solar observatory

    Get PDF
    Redundant low power PCM telemeter for OS

    Detecting Life-bearing Extra-solar Planets with Space Telescopes

    Full text link
    One of the promising methods to search for life on extra-solar planets (exoplanets) is to detect life's signatures in their atmospheres. Spectra of exoplanet atmospheres at the modest resolution needed to search for oxygen, carbon dioxide, water, and methane will demand large collecting areas and large diameters to capture and isolate the light from planets in the habitable zones around the stars. For telescopes using coronagraphs to isolate the light from the planet, each doubling of telescope diameter will increase the available sample of stars by an order of magnitude, indicating a high scientific return if the technical difficulties of constructing very large space telescopes can be overcome. For telescopes detecting atmospheric signatures of transiting planets, the sample size increases only linearly with diameter, and the available samples are probably too small to guarantee detection of life-bearing planets. Using samples of nearby stars suitable for exoplanet searches, this paper shows that the demands of searching for life with either technique will require large telescopes, with diameters of order 10m or larger in space.Comment: 15 pages, 6 figures, submitted to Ap.

    An open question: Are topological arguments helpful in setting initial conditions for transport problems in condensed matter physics?

    Full text link
    The tunneling Hamiltonian is a proven method to treat particle tunneling between different states represented as wavefunctions in many-body physics. Our problem is how to apply a wave functional formulation of tunneling Hamiltonians to a driven sine-Gordon system. We apply a generalization of the tunneling Hamiltonian to charge density wave (CDW) transport problems in which we consider tunneling between states that are wavefunctionals of a scalar quantum field. We present derived I-E curves that match Zenier curves used to fit data experimentally with wavefunctionals congruent with the false vacuum hypothesis. THe open question is whether the coefficients picked in both the wavefunctionals and the magnitude of the coefficents of the driven sine Gordon physical system should be picked by topological charge arguements that in principle appear to assign values that have a tie in with the false vacuum hypothesis first presented by Sidney ColemanComment: 17 pages, 4 figures (1a to 2b) on two pages. Specific emphasis on if or not topological arguements a la Trodden, Su et al add to formulation of condensed matter transport problem

    The Teacher of To-Morrow: An Address

    Get PDF
    This publication contains the text of an address given by Salem Normal School Principal Walter Beckwith before an unknown audience.https://digitalcommons.salemstate.edu/sns_historic/1003/thumbnail.jp

    Florida East Coast Railway and hotels: America\u27s tropical kingdom, January 1901

    Get PDF
    Travel book with illustrations and black-and-white photographs of stops along the Florida East Coast Railways line

    A New S-S' Pair Creation Rate Expression Improving Upon Zener Curves for I-E Plots

    Full text link
    To simplify phenomenology modeling used for charge density wave (CDW)transport, we apply a wavefunctional formulation of tunneling Hamiltonians to a physical transport problem characterized by a perturbed washboard potential. To do so, we consider tunneing between states that are wavefunctionals of a scalar quantum field. I-E curves that match Zener curves - used to fit data experimentally with wavefunctionals congruent with the false vacuum hypothesis. This has a very strong convergence with electron-positron pair production representations.The similarities in plot behavior of the current values after the threshold electric field values argue in favor of the Bardeen pinning gap paradigm proposed for quasi-one-dimensional metallic transport problems.Comment: 22 pages,6 figures, and extensive editing of certain segments.Paper has been revised due to acceptance by World press scientific MPLB journal. This is word version of file which has been submitted to MPLBs editor for final proofing. Due for publication perhaps in mid spring to early summer 200

    Foreword

    Get PDF
    corecore