12,254 research outputs found

    The experiences of women with polycystic ovary syndrome on a very low-calorie diet

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    The research was funded by an educational grant from LighterLife. Broom was the Medical Director for LighterLife at the time of the research. Johnson is the Head of Nutrition and Research at LighterLife. The authors report no other conflicts of interest in this work.Peer reviewedPublisher PD

    Research study of some RAM antennas Final report, 18 Nov. 1964 - 18 Jun. 1965

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    Input impedance and radiation pattern determinations for cylindrical gap, waveguide excited and circular waveguide slot antenna array

    Method to Partition Between Attached and Unattached E. coli in Runoff From Agricultural Lands 1

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72554/1/j.1752-1688.2008.00262.x.pd

    Soft lubrication: the elastohydrodynamics of non-conforming and conforming contacts

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    We study the lubrication of fluid-immersed soft interfaces and show that elastic deformation couples tangential and normal forces and thus generates lift. We consider materials that deform easily, due to either geometry (e.g. a shell) or constitutive properties (e.g. a gel or a rubber), so that the effects of pressure and temperature on the fluid properties may be neglected. Four different system geometries are considered: a rigid cylinder moving parallel to a soft layer coating a rigid substrate; a soft cylinder moving parallel to a rigid substrate; a cylindrical shell moving parallel to a rigid substrate; and finally a cylindrical conforming journal bearing coated with a thin soft layer. In addition, for the particular case of a soft layer coating a rigid substrate we consider both elastic and poroelastic material responses. For all these cases we find the same generic behavior: there is an optimal combination of geometric and material parameters that maximizes the dimensionless normal force as a function of the softness parameter = hydrodynamic pressure/elastic stiffness = surface deflection/gap thickness which characterizes the fluid-induced deformation of the interface. The corresponding cases for a spherical slider are treated using scaling concepts.Comment: 61 pages, 20 figures, 2 tables, submitted to Physics of Fluid

    Orientation and solvatochromism of dyes in liquid crystals.

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    The orientation and solvatochromism of some dye molecules in a liquid crystal have been investigated. Interactions with the host and the structure of the dye molecule affect the macroscopic alignment of dichroic dye molecules in a liquid crystal: It was observed that some dye molecules show a large bathochromic shift of their absorption maxima in the liquid crystal host relative to the situation in isotropic solvents. It is suggested that this is due to the occurrence of a much weaker reaction field in the anisotropic, rigid host. These dye molecules show little or no apparent order in the anisotropic host despite the observation of a reduction in the electro optic switching time when the dye is present. The highest degree of macroscopic alignment was observed for a merocyanine compound, which showed the smallest solvatochromic shift in the liquid crystal host. These results are discussed in terms of the steric, dipolar and hydrogen bond interactions between the guest and the host

    Developing a quality assurance metric: a panoptic view

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    This article is a post-print of the published article that may be accessed at the link below. Copyright @ 2006 Sage Publications.There are a variety of techniques that lecturers can use to get feedback on their teaching - for example, module feedback and coursework results. However, a question arises about how reliable and valid are the content that goes into these quality assurance metrics. The aim of this article is to present a new approach for collecting and analysing qualitative feedback from students that could be used as the first stage in developing more reliable quality assurance metrics. The approach, known as the multi-dimensional crystal view, is based on the belief that individuals have different views on the benefits that the embedded process in a system can have on the behaviour of the system. The results of this study indicate that in the context of evaluation and feedback methods, the multi-dimensional approach appears to provide the opportunity for developing more effective student feedback mechanisms

    Simple Front End Electronics for Multigap Resistive Plate Chambers

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    A simple circuit for the presentation of the signals from Multi-gap Resistive Plate Chambers (MRPCs) to standard existing digitization electronics is described. The circuit is based on "off-the-shelf" discrete components. An optimization of the values of specific components is required to match the aspects of the MRPCs for the given application. This simple circuit is an attractive option for the initial signal processing for MRPC prototyping and bench- or beam-testing efforts, as well as for final implementations of small-area Time-of-Flight systems with existing data acquisition systems.Comment: submitted to Nucl. Inst. and Methods, Section

    Contact and Friction of Nano-Asperities: Effects of Adsorbed Monolayers

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    Molecular dynamics simulations are used to study contact between a rigid, nonadhesive, spherical tip with radius of order 30nm and a flat elastic substrate covered with a fluid monolayer of adsorbed chain molecules. Previous studies of bare surfaces showed that the atomic scale deviations from a sphere that are present on any tip constructed from discrete atoms lead to significant deviations from continuum theory and dramatic variability in friction forces. Introducing an adsorbed monolayer leads to larger deviations from continuum theory, but decreases the variations between tips with different atomic structure. Although the film is fluid, it remains in the contact and behaves qualitatively like a thin elastic coating except for certain tips at high loads. Measures of the contact area based on the moments or outer limits of the pressure distribution and on counting contacting atoms are compared. The number of tip atoms making contact in a time interval grows as a power of the interval when the film is present and logarithmically with the interval for bare surfaces. Friction is measured by displacing the tip at a constant velocity or pulling the tip with a spring. Both static and kinetic friction rise linearly with load at small loads. Transitions in the state of the film lead to nonlinear behavior at large loads. The friction is less clearly correlated with contact area than load.Comment: RevTex4, 17 pages, 13 figure

    Morphology of meteoroid and space debris craters on LDEF metal targets

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    We measured the depths, average diameters, and circularity indices of over 600 micrometeoroid and space debris craters on various metal surfaces exposed to space on the Long Duration Exposure Facility (LDEF) satellite, as a test of some of the formalisms used to convert the diameters of craters on space-exposed surfaces into penetration depths for the purpose of calculating impactor sizes or masses. The topics covered include the following: targe materials orientation; crater measurements and sample populations; effects of oblique impacts; effects of projectile velocity; effects of crater size; effects of target hardness; effects of target density; and effects of projectile properties
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