Analyzing Laminated Structures from Fibre-Reinforced Composite Material: An Assessment

In the open literature there is available a tremendous number of models and methods for analyzing laminated structures. With respect to the assumptions across the laminate thickness, theories with Cz1-continuous functions are to be distinguished from layer-wise approaches, where for the latter the functional degrees of freedom can be dependent or independent of the number of layers. Transverse shear and normal stresses are more accurate when obtained by locally evaluating the equilibrium conditions. Guidelines are needed as to which model is suitable for what task. Especially for layer-wise models a fair judgment is missing. To ease up this deficiency two simple layer-wise models are evaluated and compared with models based on Cz1-continuous functions. It turns out that for standard application the FSDT with improved transverse shear stiffness is a good choice with respect to efficiency

A Model Archive for Simulations in a Partially-Mixed Idealized Estuary using the COAWST System: Model Code and Output

This dataset includes model input, code and output used in the publication Tarpley et al. (2019, Journal of Marine Science and Engineering), which used a coupled hydrodynamic-sediment transport model to investigate the roles of flocculation, bed consolidation and sediment-induced stratification on changes in fine-grained sediment distribution in an idealized estuarine model. The modeling system used in the development was the Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) framework

Seabed Resuspension in the Chesapeake Bay: Implications for Biogeochemical Cycling and Hypoxia

Sediment processes, including resuspension and transport, affect water quality in estuaries by altering light attenuation, primary productivity, and organic matter remineralization, which then influence oxygen and nitrogen dynamics. The relative importance of these processes on oxygen and nitrogen dynamics varies in space and time due to multiple factors and is difficult to measure, however, motivating a modeling approach to quantify how sediment resuspension and transport affect estuarine biogeochemistry. Results from a coupled hydrodynamic-sediment transport-biogeochemical model of the Chesapeake Bay for the summers of 2002 and 2003 showed that resuspension increased light attenuation, especially in the northernmost portion of the Bay, shifting primary production downstream. Resuspension also increased remineralization in the central Bay, which experienced larger organic matter concentrations due to the downstream shift in primary productivity and estuarine circulation. As a result, oxygen decreased and ammonium increased throughout the Bay in the bottom portion of the water column, due to reduced photosynthesis in the northernmost portion of the Bay and increased remineralization in the central Bay. Averaged over the channel, resuspension decreased oxygen by similar to 25% and increased ammonium by similar to 50% for the bottom water column. Changes due to resuspension were of the same order of magnitude as, and generally exceeded, short-term variations within individual summers, as well as interannual variability between 2002 and 2003, which were wet and dry years, respectively. Our results quantify the degree to which sediment resuspension and transport affect biogeochemistry, and provide insight into how coastal systems may respond to management efforts and environmental changes. Model datasets are available through W&M ScholarWorks : https://doi.org/10.25773/hamz-zc5

Symmetric hyperbolic systems for Bianchi equations

We obtain a family of first-order symmetric hyperbolic systems for the Bianchi equations. They have only physical characteristics: the light cone and timelike hypersurfaces. In the proof of the hyperbolicity, new positivity properties of the Bel tensor are used.Comment: latex, 7 pages, accepted for publication in Class. Quantum Gra

Ultracoherence and Canonical Transformations

The (in)finite dimensional symplectic group of homogeneous canonical transformations is represented on the bosonic Fock space by the action of the group on the ultracoherent vectors, which are generalizations of the coherent states.Comment: 24 page