A Method for Calculation of Hydrodynamic Lift for Submerged and Planing Rectangular Lifting Surfaces

A method is presented for the calculation of lift coefficients for rectangular lifting surfaces of aspect ratios from 0.125 to 10 operating at finite depths beneath the water surface, including the zero depth or planing condition. Theoretical values are compared with experimental values obtained at various depths of submergence with lifting surfaces of aspect ratios from 0.125 to 10. The method can also be applied to hydrofoils with dihedral. Lift coefficients computed by this method are in good agreement with existing experimental data for aspect ratios from 0.125 to 10 and dihedral angles up to 30 deg

Transitions in the morphological features, habitat use, and diet of young-of-the-year goosefish (Lophius americanus)

This study was designed to improve our understanding of transitions in the early life history and the distribution, habitat use, and diets for young-of-the-year (YOY) goosefish (Lophius americanus) and, as a result, their role in northeastern U.S. continental shelf ecosystems. Pelagic juveniles (>12 to ca. 50 mm total length [TL]) were distributed over most portions of the continental shelf in the Middle Atlantic Bight, Georges Bank, and into the Gulf of Maine. Most individuals settled by 50−85 mm TL and reached approximately 60−120 mm TL by one year of age. Pelagic YOY fed on chaetognaths, hyperiid amphipods, calanoid copepods, and ostracods, and benthic YOY had a varied diet of fishes and benthic crustaceans. Goosefish are widely scattered on the continental shelf in the Middle Atlantic Bight during their early life history and once settled, are habitat generalists, and thus play a role in many continental shelf habi

A proposal for a microcomputer-based physical qualifications monitoring system for the Branch Clinic, Bancroft Hall, Annapolis, Maryland.

http://archive.org/details/proposalformicro00setzN

Performance of diagnostic tests to detect respiratory viruses in older adults.

The performance of 4 laboratory methods for diagnosis of viral respiratory tract infections (RTI) in older adults was evaluated. Seventy-four nasopharyngeal (NP) swab specimens were obtained from 60 patients with RTI at a long-term care facility over 2 respiratory seasons. Sixteen specimens were positive for a respiratory virus by at least 1 method. Multiplex reverse transcriptase polymerase chain reaction (RT-PCR) by the Luminex xTAG Respiratory Viral Panel (RVP) detected 16 (100%) of the positive specimens, RVP of 24-h culture supernatant detected 8 (50%), direct fluorescent antibody testing detected 4 (25%), rapid culture detected 2 (12.5%), and rapid antigen testing detected none. For a comparison group, RVP was performed on NP swabs from 20 outpatient children with RTI. The mean fluorescence intensity by RVP was significantly lower for positive adult patients than pediatric patients (P = 0.0373). Our data suggest that older adult patients shed lower titers of viruses, necessitating a highly sensitive assay such as RT-PCR to reliably detect respiratory viral pathogens

A novel viscoelastic damping treatment for honeycomb sandwich structures

Journal ArticleCopyright © 2015 Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Composite Structures. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Composite Structures Vol. 119 (2015), DOI: 10.1016/j.compstruct.2014.09.005Constrained layer dampers (CLD) are in widespread use for passive vibration damping, in applications including aerospace structures which are often lightweight. The location and dimensions of CLD devices on structures has been the target of several optimisation studies using a variety of techniques such as genetic algorithms, cellular automata, and gradient techniques. The recently developed double shear lap-joint (DSLJ) damper is an alternative method for vibration damping, and can be placed internally within structures. The performance of the DSLJ damper is compared in a parametric study with that of CLD dampers on beam and plate structures under both cantilever and simply supported boundary conditions, using finite element analysis. The objective was to determine which damper and in which configuration produced the highest modal loss factor and amplitude reduction for least added mass, as would be important for lightweight applications. The DSLJ tend to be more mass efficient in terms of loss factor and amplitude reduction for cantilevered beam and plate structure, and are competitive with CLD dampers in simply supported beam and plate structures. The DSLJ works well because it has the potential to magnify global flexural deformation into shear deformation in the viscoelastic more effectively than traditional CLD dampers.MEET project (Material for Energy Efficiency in Transport) in the context of the INTERREG IV A France (Channel) – England European cross-border co-operation programme, which is co-financed by ERDF

On the effective strain tensor in heterogeneous materials

ArticleThis is the author's accepted manuscript. The final published version of record is available at https://dx.doi.org/10.1177/1081286514521092This paper considers effective strain tensors within the context of linear elastic equilibrium theory. The elastic properties of structured materials are often averaged over subvolumes of various scales inside the material. For subvolumes smaller than a representative volume element, simple volume-averaging of the stress and strain may not preserve the elastic energy. We introduce an averaging process which preserves the energy for all boundary conditions. This averaging process emphasizes the parts of the material which carry the most stress. Here the effective strain is weighted by the local stress, and can be interpreted as an average strain over all paths taken by loads and forces through the volume. This alternative effective strain may be especially appropriate for materials with voids, such as foams and granular matter, as the averaging only involves the material itself. For uniform boundary conditions the weighted strain matches the volume-averaged strain. This paper investigates the properties of this weighted strain tensor. First, for each path taken by loads and forces through the volume we can measure a net length as well as a net extension due to the linear deformation. The weighted effective strain equals the ratio of average length to average extension, where the averaging is over all possible force paths. Thus this method provides a connection to load path analysis. Secondly, even when the average rotation within the subvolume is zero, there may be local fluctuations in the rotation field. These rotations can act like a mechanism, transferring elastic energy between boundaries or degrees of freedom. The effective strain defined here highlights this mechanism effect

A novel mechanism for generating auxetic behaviour in reticulated foams : missing rib foam model

Foams have previously been fabricated with a negative Poisson's ratio (termed auxetic foams). A novel model is proposed to explain this and to describe the strain-dependent Poisson's function behaviour of honeycomb and foam materials. The model is two-dimensional and is based upon the observation of broken cell ribs in foams processed via the compression and heating technique usually employed to convert conventional foams to auxetic behaviour. The model has two forms: the “intact” form is a network of ribs with biaxial symmetry, and the “auxetic” form is a similar network but with a proportion of cell ribs removed. The model output is compared with that of an existing two-dimensional model and experimental data, and is found to be superior in predicting the Poisson's function and marginally better at predicting the stress–strain behaviour of the experimental data than the existing model, using realistic values for geometric parameters.peer-reviewe