13,727 research outputs found

    Fatigue testing a plurality of test specimens and method

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    Described is a fatigue testing apparatus for simultaneously subjecting a plurality of material test specimens to cyclical tension loading to determine the fatigue strength of the material. The fatigue testing apparatus includes a pulling head having cylinders defined therein which carry reciprocating pistons. The reciprocation of the pistons is determined by cyclical supplies of pressurized fluid to the cylinders. Piston rods extend from the pistons through the pulling head and are attachable to one end of the test specimens, the other end of the test specimens being attachable to a fixed base, causing test specimens attached between the piston rods and the base to be subjected to cyclical tension loading. Because all the cylinders share a common pressurized fluid supply, the breaking of a test specimen does not substantially affect the pressure of the fluid supplied to the other cylinders nor the tension applied to the other test specimens

    Draft Genome Sequence of Frankia sp. Strain CcI6, a Salt-Tolerant Nitrogen-Fixing Actinobacterium Isolated from the Root Nodule of Casuarina cunninghamiana

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    Members of the actinomycete genus Frankia form a nitrogen-fixing symbiosis with 8 different families of actinorhizal plants. We report a 5.57-Mbp draft genome sequence for Frankia sp. strain CcI6, a salt-tolerant nitrogen-fixing actinobacterium isolated from root nodules of Casurina cunninghamiana grown in Egyptian soils

    A Density Independent Formulation of Smoothed Particle Hydrodynamics

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    The standard formulation of the smoothed particle hydrodynamics (SPH) assumes that the local density distribution is differentiable. This assumption is used to derive the spatial derivatives of other quantities. However, this assumption breaks down at the contact discontinuity. At the contact discontinuity, the density of the low-density side is overestimated while that of the high-density side is underestimated. As a result, the pressure of the low (high) density side is over (under) estimated. Thus, unphysical repulsive force appears at the contact discontinuity, resulting in the effective surface tension. This tension suppresses fluid instabilities. In this paper, we present a new formulation of SPH, which does not require the differentiability of density. Instead of the mass density, we adopt the internal energy density (pressure), and its arbitrary function, which are smoothed quantities at the contact discontinuity, as the volume element used for the kernel integration. We call this new formulation density independent SPH (DISPH). It handles the contact discontinuity without numerical problems. The results of standard tests such as the shock tube, Kelvin-Helmholtz and Rayleigh-Taylor instabilities, point like explosion, and blob tests are all very favorable to DISPH. We conclude that DISPH solved most of known difficulties of the standard SPH, without introducing additional numerical diffusion or breaking the exact force symmetry or energy conservation. Our new SPH includes the formulation proposed by Ritchie & Thomas (2001) as a special case. Our formulation can be extended to handle a non-ideal gas easily.Comment: 24 pages, 21 figures. Movies and high resolution figures are available at http://v1.jmlab.jp/~saitoh/sph/index.htm

    A longitudinal evaluation of a project-based learning initiative in an engineering undergraduate programme

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    Project-based learning (PBL) is a well-known student-centred methodology for engineering design education. The methodology claims to offer a number of educational benefits. This paper evaluates the student perceptions of the initial and second offering of a first-year design unit at Griffith University in Australia. It builds on an earlier evaluation conducted after the initial offering of the unit. It considers the implementation of the recommended changes. Evaluations of the two offerings reveal that students (in both the initial and second offering) generally enjoyed the experience, but that the second offering was found to be a significantly more enjoyable learning experience. Students in the second offering also reported a significantly better understanding of what they needed to do for the design projects and where to find the requisite information. The oral presentation aspect of the initial and second offerings received the lowest satisfaction rating. The inclusion (and delivery) of the computer-aided drawing component of the unit is seen as a positive aspect by some students, but many others comment on it negatively. The best aspects of the PBL unit and those aspects needing further improvement were similar to the findings of other investigations documented in the literature

    Explorations in anatomy: the remains from Royal London Hospital

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    This paper considers the faunal remains from recent excavations at the Royal London Hospital. The remains date to the beginning of the 19th century and offer an insight into the life of the hospital's patients and practices of the attached medical school. Many of the animal remains consist of partially dissected skeletons, including the unique finds of Hermann's tortoise (Testudo hermanni) and Cercopithecus monkey. The hospital diet and developments in comparative anatomy are discussed by integrating the results with documentary research. They show that zooarchaeological study of later post-medieval material can significantly enhance our understanding of the exploitation of animals in this perio

    How primary care can contribute to good mental health in adults.

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    The need for support for good mental health is enormous. General support for good mental health is needed for 100% of the population, and at all stages of life, from early childhood to end of life. Focused support is needed for the 17.6% of adults who have a mental disorder at any time, including those who also have a mental health problem amongst the 30% who report having a long-term condition of some kind. All sectors of society and all parts of the NHS need to play their part. Primary care cannot do this on its own. This paper describes how primary care practitioners can help stimulate such a grand alliance for health, by operating at four different levels - as individual practitioners, as organisations, as geographic clusters of organisations and as policy-makers

    Permanent Draft Genome sequence for Frankia sp. strain CcI49, a Nitrogen-Fixing Bacterium Isolated from Casuarina cunninghamiana that Infects Elaeagnaceae

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    Frankia sp. strain CcI49 was isolated from Casuarina cunninghamiana nodules. However the strain was unable to re-infect Casuarina, but was able to infect other actinorhizal plants including Elaeagnaceae. Here, we report the 9.8-Mbp draft genome sequence of Frankia sp. strain CcI49 with a G+C content of 70.5 % and 7,441 candidate protein-encoding genes. Analysis of the genome revealed the presence of a bph operon involved in the degradation of biphenyls and polychlorinated biphenyls
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