9,886 research outputs found
Cirrus cloud model parameterizations: Incorporating realistic ice particle generation
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
Civil rights suits against the police are an essential tool for enforcing the Constitution. But cops rarely pay and settlements don’t lead to change.
Last year’s protests in response to the shooting by police of Michael Brown in Ferguson, Missouri, has brought the issue of police accountability to the national stage. Lynda G. Dodd writes that while civil constitutional lawsuits have a much greater scope for holding police officers accountable compared to the Department of Justice, such suits are the ‘worst of both worlds’; they are rarely successful, and even when they are, police officers are shielded from paying fees or damages by their employers. She argues that reforms targeting data collection around police misconduct are likely to do the most to strengthen civil litigation as a deterrent
How to protect a wind turbine from lightning
Techniques for reducing the chances of lightning damage to wind turbines are discussed. The methods of providing a ground for a lightning strike are discussed. Then details are given on ways to protect electronic systems, generating and power equipment, blades, and mechanical components from direct and nearby lightning strikes
Darboux transformation and multi-soliton solutions of Two-Boson hierarchy
We study Darboux transformations for the two boson (TB) hierarchy both in the
scalar as well as in the matrix descriptions of the linear equation. While
Darboux transformations have been extensively studied for integrable models
based on within the AKNS framework, this model is based on
. The connection between the scalar and the matrix
descriptions in this case implies that the generic Darboux matrix for the TB
hierarchy has a different structure from that in the models based on
studied thus far. The conventional Darboux transformation is shown to be quite
restricted in this model. We construct a modified Darboux transformation which
has a much richer structure and which also allows for multi-soliton solutions
to be written in terms of Wronskians. Using the modified Darboux
transformations, we explicitly construct one soliton/kink solutions for the
model.Comment:
Some Factors Affecting the Influence of Soybeans, Oats, and Other Crops on the Succeeding Crop
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