77,049 research outputs found

    The remote sensing of Saturn's rings. 1: The magnetic alinement of the ring particles

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    Because of the potential implications for the optical properties of Saturn's rings, the orientation of nonspherical ring particles at equilibrium is investigated with respect to four stochastic influences: interactions with the interplanetary medium, interactions with the expected magnetic field of Saturn, thermal fluctuations due to the internal temperature of the ring particles; collisions between ring particles. The solution of the homogeneous Fokker-Planck equation for nearly spherical spheroids is presented and investigated in general. Values of the pertinent physical parameters in the vicinity of Saturn are estimated, and the implications for the alignment of the ring particles are investigated. It is concluded that for some alignment mechanisms, small ring particles can be expected to be almost completely aligned. This alignment results in each particle spinning around its shortest body axis with this axis parallel to the magnetic field direction (perpendicular to the ring plane)

    On the Geometric Principles of Surface Growth

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    We introduce a new equation describing epitaxial growth processes. This equation is derived from a simple variational geometric principle and it has a straightforward interpretation in terms of continuum and microscopic physics. It is also able to reproduce the critical behavior already observed, mound formation and mass conservation, but however does not fit a divergence form as the most commonly spread models of conserved surface growth. This formulation allows us to connect the results of the dynamic renormalization group analysis with intuitive geometric principles, whose generic character may well allow them to describe surface growth and other phenomena in different areas of physics

    Autoignition test cell Patent

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    Test chamber for determining decomposition and autoignition of materials used in spacecraft under controlled environmental condition

    Torsion pendulum measurements on viscoelastic materials during vacuum exposure

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    A torsional pendulum apparatus designed for testing in situ in vacuum, the dynamic mechanical properties of materials is described. The application of this apparatus to an experimental program to measure the effects of vacuum on the mechanical properties of two ablator materials (a foamed material and a filled elastomer) and a solid rocket propellant (a filled elastomer) is presented. Results from the program are discussed as to the effects of vacuum on the mechanical properties of these three materials. In addition, time-temperature-superposition, as a technique for accelerating vacuum induced changes in mechanical properties, is discussed with reference to the three materials tested in the subject program

    Understanding the Effect of Television Advertising on Women's Attitudes and Purchase Intentions Towards Beer: A Study of Three Major Brands.

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    Abstract Purpose of Paper: The market for beer in the UK is now mature and sales have been stable at around £16bn for about ten years (Mintel 2014). More recently, there have been changes in the market as consumers have switched from bigger mainstream brands to a growing number of smaller craft beers. However, in order to grow further significantly, the industry needs to explore new market segments and find new consumers for beer. So far, it is estimated that only 1.3m women in the UK drink beer (O'Reilly, 2014; Mail Online, 2015). Women are therefore an underexplored segment and present the main growth opportunity for beer drinking in the UK. However, most beer television advertising has traditionally been aimed at the male audience and there have been suggestions that some of this advertising has been seen as unpopular with or even insulting to women (Jackson, 2013; Zwarun et al., 2006). The Chief Executive of major brewer SAB Miller, which owns the Foster's brand, has recently written that, 'We have to acknowledge that core lager advertising, for many years, was either dismissive of, or insulting to, women.' (Shubber, 2015). If women are to be the new consumers and the future target for beer advertising, there is therefore a significant gap in the knowledge and literature concerned with how women differ from men in responding to the television advertising produced by beer brands and it is important that this gap in knowledge is addressed. The purpose of this paper is therefore to explore the effect of the television advertising of the three top selling UK beer brands on women's attitudes and purchase intentions towards those brands. More specifically, the objectives are: 1) To gain an understanding of how female consumers respond to existing beer television advertising, specifically in terms of the ‘likeability’ of the content of TV commercials produced by the three leading UK beer brands among female consumers. 2) To examine the effect of the rational and emotional content, including the use of humour, in television commercials produced by the three leading UK beer brands on the attitudes of female consumers towards those brands. 3) To explore in-depth female consumer attitudes towards the content (message cues and symbolism) of the television commercials produced by the three leading beer brands in the UK and their effect on subsequent purchase intentions for each brand

    Secondary prevention of stroke: Using the experiences of patients and carers to inform the development of an educational resource

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    Copyright @ The Author 2008. This article is available open access through the publisher’s website at the link below.Background. Patients who have had one stroke are at increased risk of another. Secondary prevention strategies that address medical risk factors and promote healthy lifestyles can reduce the risk. However, concordance with secondary prevention strategies is poor and there has been little research into patient and carer views. Objectives. To explore the experiences of patients and carers of receiving secondary prevention advice and use these to inform the development of an educational resource. Methods. A total of 38 participants (25 patients and 13 carers) took part in the study which used an action research approach. Focus groups and interviews were undertaken with patients and carers who had been discharged from hospital after stroke (between 3 and 24 months previously). Framework analysis was used to examine the data and elicit action points to develop an educational resource. Results. Participants’ main concern was their desire for early access to information. They commented on their priorities for what information or support they needed, the difficulty of absorbing complex information whilst still an in-patient and how health professionals’ use of language was often a barrier to understanding. They discussed the facilitators and barriers to making lifestyle changes. The educational resource was developed to include specific advice for medical and lifestyle risk factors and an individual action plan. Conclusion. An educational resource for secondary prevention of stroke was developed using a participatory methodology. Our findings suggest that this resource is best delivered in a one-to-one manner, but further work is needed to identify its potential utility.Peninsula Primary Care Research Networ

    High-Speed Projects in the United States: Identifying the Elements for Success-Part 1, MTI Report 05-01

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    For almost half a century, high-speed ground transportation (HSGT) has held the promise of fast, convenient, and environmentally sound travel for distances between 40 and 600 miles. While a number of HSGT systems have been developed and deployed in Asia and Europe, none has come close to being implemented in the United States. Yet this is not for lack of trying. There have been several efforts around the country, most of which have failed, some of which are still in the early stages, and a few of which might come to pass. The goal of this study was to identify lessons learned for successfully developing and implementing high-speed rail (HSR) in the United States. Through a broad literature review, interviews, and three specific case studies—Florida, California, and the Pacific Northwest—this study articulates those lessons and presents themes for future consideration

    Hard rod gas with long-range interactions: Exact predictions for hydrodynamic properties of continuum systems from discrete models

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    One-dimensional hard rod gases are explicitly constructed as the limits of discrete systems: exclusion processes involving particles of arbitrary length. Those continuum many-body systems in general do not exhibit the same hydrodynamic properties as the underlying discrete models. Considering as examples a hard rod gas with additional long-range interaction and the generalized asymmetric exclusion process for extended particles (â„“\ell-ASEP), it is shown how a correspondence between continuous and discrete systems must be established instead. This opens up a new possibility to exactly predict the hydrodynamic behaviour of this continuum system under Eulerian scaling by solving its discrete counterpart with analytical or numerical tools. As an illustration, simulations of the totally asymmetric exclusion process (â„“\ell-TASEP) are compared to analytical solutions of the model and applied to the corresponding hard rod gas. The case of short-range interaction is treated separately.Comment: 19 pages, 8 figure

    A proof of Jarzynski's non-equilibrium work theorem for dynamical systems that conserve the canonical distribution

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    We present a derivation of the Jarzynski identity and the Crooks fluctuation theorem for systems governed by deterministic dynamics that conserves the canonical distribution such as Hamiltonian dynamics, Nose-Hoover dynamics, Nose-Hoover chains and Gaussian isokinetic dynamics. The proof is based on a relation between the heat absorbed by the system during the non-equilibrium process and the Jacobian of the phase flow generated by the dynamics.Comment: 12 page

    Infrared Observations of novae in the SOFIA era

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    Classical novae inject chemically enriched gas and dust into the local inter-stellar medium (ISM). Abundances in the ejecta can be deduced from infrared (IR) forbidden line emission. IR spectroscopy can determine the mineralogy of grains that grow in nova ejecta. We anticipate the impact that NASA's new Stratospheric Observatory for Infrared Astronomy (SOFIA) will have on future IR studies of novae.Comment: To appear in the proceedings of "Physics of Evolved Stars 2015 - A conference dedicated to the memory of Olivier Chesneau
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