3,203 research outputs found

    Pollution From Sewage Loading in River and Lakes Downstream from Bemidji

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    The deleterious effects and downstream distribution of pollutants from domestic sewage discharged at Bemidji, Minnesota, are examined with reference lo parameters for pollution as defined by the state\u27s Pollution Control Agency (PCA). Periodic overloading of the resort city\u27s sewage treatment plant also is considered, along with problems pertinent to a community upstream of popular vacation facilities on a lake and river system

    General description of electromagnetic radiation processes based on instantaneous charge acceleration in `endpoints'

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    We present a new methodology for calculating the electromagnetic radiation from accelerated charged particles. Our formulation --- the `endpoint formulation' --- combines numerous results developed in the literature in relation to radiation arising from particle acceleration using a complete, and completely general, treatment. We do this by describing particle motion via a series of discrete, instantaneous acceleration events, or `endpoints', with each such event being treated as a source of emission. This method implicitly allows for particle creation/destruction, and is suited to direct numerical implementation in either the time- or frequency-domains. In this paper, we demonstrate the complete generality of our method for calculating the radiated field from charged particle acceleration, and show how it reduces to the classical named radiation processes such as synchrotron, Tamm's description of Vavilov-Cherenkov, and transition radiation under appropriate limits. Using this formulation, we are immediately able to answer outstanding questions regarding the phenomenology of radio emission from ultra-high-energy particle interactions in both the Earth's atmosphere and the Moon. In particular, our formulation makes it apparent that the dominant emission component of the Askaryan Effect (coherent radio-wave radiation from high-energy particle cascades in dense media) comes from coherent `bremsstrahlung' from particle acceleration, rather than coherent Vavilov-Cherenkov radiation.Comment: accepted by Phys. Rev. E, new title, some corrections in equations and references, figure styles updated to match journal policie

    A Basis for Legislation to Encourage Conservation of Automobile Energy Fuel

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    A detailed basis for legislation to institute a system of rating automobiles according to their energy costs is proposed, together with mechanisms to tax wasteful uses of energy associated with cars. A complementary rebate system for owners of very efficient vehicles also is proposed. This proposal is advanced instead of systems of increasing energy supplies or gasoline rationing to control consumer demand

    Teff and log g dependence of velocity fields in M-stars

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    We present an investigation of velocity fields in early to late M-type hydrodynamic stellar atmosphere models. These velocities will be expressed in classical terms of micro- and macro-turbulent velocities for usage in 1D spectral synthesis. The M-star model parameters range between log g of 3.0 - 5.0 and Teff of 2500 K - 4000 K. We characterize the Teff- and log g-dependence of the hydrodynamical velocity fields in these models with a binning method, and for the determination of micro-turbulent velocities, the Curve of Growth method is used. The macro-turbulent velocities are obtained by convolutions with Gaussian profiles. Velocity fields in M-stars strongly depend on log g and Teff. Their velocity amplitudes increase with decreasing log g and increasing Teff. The 3D hydrodynamical and 1D macro-turbulent velocities range from ~100 m/s for cool high gravity models to ~ 800 m/s - 1000 m/s for hot models or models with low log g. The micro-turbulent velocities range in the order of ~100 m/s for cool models, to ~600 m/s for hot or low log g models. Our M-star structure models are calculated with the 3D radiative-hydrodynamics (RHD) code CO5BOLD. The spectral synthesis on these models is performed with the line synthesis code LINFOR3D.Comment: 8 pages, 6 Figures, Proceeding fot the "Recent directions in astrophysical quantitative spectroscopy and radiation hydrodynamics" conferenc

    Inventory of Non-Energy Sources of Greenhouse Gas Emissions in Hawaii Phase I

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    International concern for global climate change has stimulated a wide range of data gathering and analysis efforts worldwide. The recognition that certain atmospheric gases, many of which are anthropogenic in origin, have the capacity to absorb infrared radiation-and thus trap heat in the atmosphere--has focused research efforts on these so-called "greenhouse" gases. In order for a country to assess its contribution to such global warming, it must first develop an emissions inventory of greenhouse gas sources and sinks. In the United States, the U.S. Environmental Protection Agency (EPA) has recently published such an inventory (U.S. EPA, 1994) and has been funding the efforts of each state to develop their own inventories of sources of greenhouse gas emissions (U.S. EPA, 1995, hereafter titled the State Phase I Workbook). It is this latter document which serves as the basis for the present report by providing the bulk of its overall methodology.Clean Air Branch, Department of Health, State of Hawai

    Simulation of radio emission from cosmic ray air shower with SELFAS2

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    We present a microscopic computation of the radio emission from air showers initiated by ultra-high energy cosmic rays in the atmosphere. The strategy adopted is to compute each secondary particle contribution of the electromagnetic component and to construct the total signal at any location. SELFAS2 is a code which doesn't rely on air shower generators like AIRES or CORSIKA and it is based on the concept of air shower universality which makes it completely autonomous. Each positron and electron of the air shower is generated randomly following relevant distributions and tracking them along their travel in the atmosphere. We confirm in this paper earlier results that the radio emission is mainly due to the time derivative of the transverse current and the time derivative of the charge excess. The time derivative of the transverse current created by systematic deviations of charges in the geomagnetic field is usually dominant compared to the charge excess contribution except for the case of an air shower parallel to the geomagnetic field.Comment: 17 pages, 21 figure

    Plant Carbonic Anhydrases: Structures, Locations, Evolution, and Physiological Roles

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    © 2017 The Authors Carbonic anhydrases (CAs) are zinc metalloenzymes that catalyze the interconversion of CO2 and HCO3− and are ubiquitous in nature. Higher plants contain three evolutionarily distinct CA families, αCAs, βCAs, and γCAs, where each family is represented by multiple isoforms in all species. Alternative splicing of CA transcripts appears common; consequently, the number of functional CA isoforms in a species may exceed the number of genes. CAs are expressed in numerous plant tissues and in different cellular locations. The most prevalent CAs are those in the chloroplast, cytosol, and mitochondria. This diversity in location is paralleled in the many physiological and biochemical roles that CAs play in plants. In this review, the number and types of CAs in C3, C4, and crassulacean acid metabolism (CAM) plants are considered, and the roles of the α and γCAs are briefly discussed. The remainder of the review focuses on plant βCAs and includes the identification of homologs between species using phylogenetic approaches, a consideration of the inter- and intracellular localization of the proteins, along with the evidence for alternative splice forms. Current understanding of βCA tissue-specific expression patterns and what controls them are reviewed, and the physiological roles for which βCAs have been implicated are presented
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