4,216 research outputs found

    Evaluation of Modification of the Upper Batavia Dam on the Fox River, Illinois

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    Progress Report, Federal Aid Project F-136-R Segment 6Report issued on: August 2004Submitted to Office of Water Resources, Illinois Department of Natural Resource

    Microphysical fundamentals governing cirrus cloud growth: Modeling studies

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    For application to Global Climate Models, large scale numerical models of cirrus cloud formation and maintenance need to be refined to more reliably simulate the effects and feedbacks of high level clouds. A key aspect is how ice crystal growth is initiated in cirrus, which has started a cloud microphysical controversy between camps either believing that heterogeneous or homogeneous drop freezing is predominantly responsible for cold cirrus ice crystal nucleation. In view of convincing evidence for the existence of highly supercooled cloud droplets in the middle and upper troposphere, however, it is concluded that active ice nuclei are rather scarce at cirrus cloud altitudes, and so a new understanding of cirrus cloud formation is needed. This understanding is sought through an examination of cirrus cloud growth models

    Cirrus cloud model parameterizations: Incorporating realistic ice particle generation

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    Recent cirrus cloud modeling studies have involved the application of a time-dependent, two dimensional Eulerian model, with generalized cloud microphysical parameterizations drawn from experimental findings. For computing the ice versus vapor phase changes, the ice mass content is linked to the maintenance of a relative humidity with respect to ice (RHI) of 105 percent; ice growth occurs both with regard to the introduction of new particles and the growth of existing particles. In a simplified cloud model designed to investigate the basic role of various physical processes in the growth and maintenance of cirrus clouds, these parametric relations are justifiable. In comparison, the one dimensional cloud microphysical model recently applied to evaluating the nucleation and growth of ice crystals in cirrus clouds explicitly treated populations of haze and cloud droplets, and ice crystals. Although these two modeling approaches are clearly incompatible, the goal of the present numerical study is to develop a parametric treatment of new ice particle generation, on the basis of detailed microphysical model findings, for incorporation into improved cirrus growth models. For example, the relation between temperature and the relative humidity required to generate ice crystals from ammonium sulfate haze droplets, whose probability of freezing through the homogeneous nucleation mode are a combined function of time and droplet molality, volume, and temperature. As an example of this approach, the results of cloud microphysical simulations are presented showing the rather narrow domain in the temperature/humidity field where new ice crystals can be generated. The microphysical simulations point out the need for detailed CCN studies at cirrus altitudes and haze droplet measurements within cirrus clouds, but also suggest that a relatively simple treatment of ice particle generation, which includes cloud chemistry, can be incorporated into cirrus cloud growth

    Lime for West Virginia Farms

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    Orphan, Indiana

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    Orphan, Indiana is a collection of spontaneous outbursts framed by reticence and the guiding mania of the subconscious. Profane and poignant, accidental-seeming but soaring with satirical intent, David Dodd Lee\u27s poems capture a verisimilitude that\u27s phenomenological, and yet of the moment.https://ideaexchange.uakron.edu/uapress_publications/1141/thumbnail.jp

    Shot by Boy Hawkins and Lee Die in a Flooded Quarry

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    Combination antidepressants : use by GPs and psychiatrists

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    Background : Current treatment of depression fails to achieve remission in 50% of patients. Combinations of two antidepressants are used by some Australian psychiatrists.Objective : This article investigates the pros and cons of combination antidepressant therapy and provides suggestions for when to consider their use, which combinations to choose, and how to introduce combination antidepressant therapies.Discussion : Combining two antidepressants is a controversial strategy, with supporters and critics arguing its efficacy and safety from opposing perspectives. The use of combination antidepressant therapies may facilitate remission from depression. However, there is limited evidence supporting these treatments, and safety concerns are often cited. There is some support for combination therapies in selected cases from international bodies. After considering risks and benefits on a case-by-case basis, careful use of selected combination antidepressant therapy may be one of a range of effective treatments for some individuals suffering from depression.<br /

    Structural stability of finite dispersion-relation preserving schemes

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    The goal of this work is to determine classes of travelling solitary wave solutions for a differential approximation of a finite difference scheme by means of a hyperbolic ansatz. It is shown that spurious solitary waves can occur in finite-difference solutions of nonlinear wave equation. The occurance of such a spurious solitary wave, which exhibits a very long life time, results in a non-vanishing numerical error for arbitrary time in unbounded numerical domain. Such a behavior is referred here to has a structural instability of the scheme, since the space of solutions spanned by the numerical scheme encompasses types of solutions (solitary waves in the present case) that are not solution of the original continuous equations. This paper extends our previous work about classical schemes to dispersion-relation preserving schemes
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