We consider a bilinear reduced-strain finite element of the MITC family for a shallow Reissner-Naghdi type shell. We estimate the consistency error of the element in both membraneand bending-dominated states of deformation. We prove that in the membrane-dominated case, under severe assumptions on the domain, the finite element mesh and the regularity of the solution, an error bound O(h + t−1h1+...

The thermal fluctuations of membranes and nanoscale shells affect their mechanical characteristics. Whereas these fluctuations are well understood for flat membranes, curved shells show anomalous behavior due to the geometric coupling between in-plane elasticity and out-of-plane bending. Using conventional shallow shell theory in combination with equilibrium statistical physics we theoretically...

The buoyancy organelles of aquatic microorganisms have to meet stringent specifications: allowing gases to equilibrate freely across the proteinaceous shell, preventing the condensation of water vapor inside the hollow cavity and resisting collapse under hydrostatic pressures that vary with column depth. These properties are provided by the 7- to 8-kDa gas vesicle protein A (GvpA), repeats of w...

The shallow shells, characterized by deeections of the order of unity, small deformations and still smaller curvatures, have most thoroughly been studied in the literature. However, the momentum terms, due to which the shell diiers essentially from a membrane, are not negligible only for the shortwave length deformations, when the deeections are small, the deformations | of the order of unity a...

When oil and gas platforms become obsolete they go through a decommissioning process. This may include partial removal (from the surface to 26 m depth) or complete removal of the platform structure. While complete removal would likely eliminate most of the existing fish biomass and associated secondary production, we find that the potential impacts of partial removal would likely be limited on ...

This study deals with the vibrational behavior of two joined cross-ply laminated conical shells. Natural frequencies and mode shapes are investigated. Joined conical shells can be considered as a general case for joined cylindrical-conical shells, joined cylinderplates or cone-plates, cylindrical and conical shells with stepped thicknesses and also annular plates. Governing equations are obtain...

Farmerella exoporosa gen. et sp.nov. is described from cold-water Permian (Bernacchian-Lymingtonian) rocks of Tasmania. The new taxon is essentially homeomorphic with Glendonia McClung & Armstrong, 1978. However, Glendonia possesses a micro-ornament of low, elongate microspines behind shallow, elongate grooves, whereas Farmerella gen.nov. (as in Notospirifir Harrington, 1955) has deep, elongate...

Evidence of increasing concentrations of dissolved carbon dioxide, especially in the surface ocean and its associated impacts on calcifying organisms, is accumulating. Among these organisms, benthic and planktonic foraminifera are responsible for a large amount of the globally precipitated calcium carbonate. Hence, their response to an acidifying ocean may have important consequences for future...

Morphological classification and mitochondrial phylogeny of a pair of morphologically defined species of New Caledonian freshwater gastropods, Hemistomia cockerelli and Hemistomia fabrorum, were incongruent. We asked whether these two nominal species can be unambiguously distinguished based on shell morphology or whether the taxonomic discrepancy inferred from these character types was reflecte...