6,916 research outputs found

    Measurement of the linear viscoelastic behavior of antimisting kerosene

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    Measurements of dynamic viscoelastic properties in very small oscillating shear deformations was made on solutions of a jet fuel, Jet A, containing an antimisting polymeric additive, FM-9. A few measurements were also made on solutions of FM-9 in a mixed solvent of mineral oil, Tetralin, and 0-terphenyl. Two samples of FM-9 had approximate number-average molecular weights of 12,000,000 and 8,100,000 as deduced from analysis of the measurements. The ranges of variables were 2.42 to 4.03 g/1 in concentration (0.3 to 0.5% by weight), 1 to 35 in temperature, 1.3 to 9.4 cp in solvent viscosity, and 103 to 6100 Hz in frequency. Measurements in the Jet A solvent were made both with and without a modifying carrier. The results were compared with the Zimm theory and the viscoelastic behavior was found to resemble rather closely that of ordinary non-polar polymers in theta solvents. The relation of the results to the antithixotropic behavior of such solutions a high shear rates is discussed in terms of intramolecular and intermolecular interactions

    On the mechanism of the highly viscous flow

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    The asymmetry model for the highly viscous flow postulates thermally activated jumps from a practically undistorted ground state to strongly distorted, but stable structures, with a pronounced Eshelby backstress from the distorted surroundings. The viscosity is ascribed to those stable distorted structures which do not jump back, but relax by the relaxation of the surrounding viscoelastic matrix. It is shown that this mechanism implies a description in terms of the shear compliance, with a viscosity which can be calculated from the cutoff of the retardation spectrum. Consistency requires that this cutoff lies close to the Maxwell time. The improved asymmetry model compares well with experiment.Comment: 8 pages, 3 figures, 49 references; revised version accepted in Journal of Chemical Physic

    Searching for Earthquake Sources in the Lower Tagus Valley (Portugal): First Results from the ATESTA Project

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    The area of Lisbon has been struck by destructive earthquakes in the past and with very intense consequences. As of today, two main areas host active faults with concern for the region: offshore with the still unclear source of the famous and catastrophic 1755 earthquake and inland with the Lower Tagus Valley where unknown fault(s) have produced the 1909 and 1531 events with estimated magnitudes ranging from 6 to 7. Those latter events are of particular importance due to their location within an area that is now densely populated. The repetition of such a shock today would have a barely imaginable impact on the population and economy of Portugal. An apparent paradox is that in spite of the high stake and expected impact on the Greater Lisbon area, little is known about the source fault(s) of the 1531 and 1909 earthquakes in terms of location, dimensions, maximum magnitude, slip rate and recurrence period. The ATESTA Project aims at answering those questions by deploying an integrated paleoseismological approach to the Lower Tagus Valley. By combining detailed geomorphological mapping using high-resolution digital eleva- tion models with shallow geophysical imaging (reflection seismics, electrical tomography and ground-penetrating radar), our goal is to identify the continuation of crustal faults at the surface. Paleoseismic trenching is conse- quently used to characterize surface rupture in terms of large recent events. Preliminary results suggest the presence of several fault trace in the Lower Tagus Valley outlined by uplifted ter- races and offset streams and visible in satellite images and the national 10-m-resolution digital elevation model. Those fault traces correspond to structures at depth, as identified by geophysical imaging

    "Any lady can do this without much trouble ...": class and gender in The dining room (1878)

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    Macmillan's "Art at Home" series (1876–83) was a collection of domestic advice manuals. Mentioned in every study of the late-nineteenth-century domestic interior, they have often been interpreted, alongside contemporary publications such as Charles Eastlake's Hints on Household Taste (1868), as indicators of late 1870s home furnishing styles. Mrs Loftie's The Dining Room (1878) was the series' fifth book and it considers one of the home's principal (and traditionally masculine) domestic spaces. Recent research on middle-class cultural practices surrounding food has placed The Dining Room within the tradition of Mrs Beeton's Household Management (1861); however, it is not a cookery book and hardly mentions dinners. Drawing upon unpublished archival sources, this paper charts the production and reception of The Dining Room, aiming to unravel its relationships with other contemporary texts and to highlight the difficulties of using it as historical evidence. While it offers fascinating insights into contemporary taste, class and gender, this paper suggests that, as an example of domestic design advice literature, it reveals far more about the often expedient world of nineteenth-century publishing practices

    Supply Chain Practice, Supply Chain Performance Indicators and Competitive Advantage of Australian Beef Enterprises: A Conceptual Framework

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    This research focuses on an Australian agribusiness supply chain, the Australian Beef Supply Chain. The definition of the Australian Beef Supply Chain is the chain or sequence of all activities from the breeding property to the domestic or overseas consumers. The beef sector in Australia is undergoing rapid change because of globalisation, a highly competitive beef market (local and export), quicker production cycle and delivery times and consequently reduced inventories, a general speed-up of the rate of change in the business environment, the trend toward more outsourcing of activities, and the rapid development of IT. In this business environment, advanced supply chain systems have the potential to provide significant contributions to Australian beef industry performance. A conceptual framework of the research project has been proposed. There are three elements of conceptual framework. Firstly, supply chain practice of Australian beef industry consists of five sub-elements such as strategic supplier partnerships, customer relationships, information sharing, information quality and a lean system. Moreover, there is an antecedent of cooperative behaviour such as trust and commitment influencing supply chain practice and supply chain performance indicators. Secondly, supply chain performance indicators include four sub-elements such as flexibility, efficiency, food quality and responsiveness. Finally, the competitive advantage framework of the Australian beef enterprises consists of price, quality, export sales growth and time to market. As a further step of the research after developing the conceptual framework, the research project focuses the analysis on how the antecedents of the sub-elements of supply chain practice affect supply chain performance in Australian beef enterprises, how trust and commitment in trading partners affect supply chain performance, how attributes such as flexibility, efficiency, food quality and responsiveness influence the sub-elements of competitive advantage. The research project leads on to further work on how Australian beef enterprises measure their supply chain performance and what the major difficulties are arising when implementing supply chain management in the Australian beef industry and what kind of changes can be made to beef supply chains to enhance their performance.Agribusiness,

    Asia-Europe: the third link

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    The report provides a comprehensive analysis of Europe-East Asia interdependences (in terms of relative economic weights, trade and financial integration, trade and financial flows, exchange rate and wealth transfers). The prime motivation of the paper is that linkages between Europe and East Asia remain frequently underestimated. While the “third link†between them is in many respects as important as the linkages between the two regions and North America, it is too often regarded only as of secondary importance.Regional integration, Financial integration, Trade integration, East Asia, European Monetary Union, Pisani-Ferry , Cohen-Setton

    Scattering of Dirac electrons by circular mass barriers: valley filter and resonant scattering

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    The scattering of two-dimensional (2D) massless Dirac electrons is investigated in the presence of a random array of circular mass barriers. The inverse momentum relaxation time and the Hall factor are calculated and used to obtain parallel and perpendicular resistivity components within linear transport theory. We found a non zero perpendicular resistivity component which has opposite sign for electrons in the different K and K' valleys. This property can be used for valley filter purposes. The total cross-section for scattering on penetrable barriers exhibit resonances due to the presence of quasi-bound states in the barriers that show up as sharp gaps in the cross-section while for Schr\"{o}dinger electrons they appear as peaks.Comment: 10 pages, 11 figure

    Cost Growth Above Inflation (CGAI) in Operating and Support (O&S) Costs in Raw Materials for Air Force Aircraft

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    Cost growth above inflation (CGAI) is the cost growth that exists after adjusting for the effects of currency inflation over time. The time value of money would suggest the increase in Operating and Support (O&S) costs over time would only be affected by inflation. In essence, every year aircraft need to be maintained at the same level and O&S costs should not change, assuming the same level of requirements. If CGAI exists in O&S there will be a large inaccuracy in the total life cycle cost (LCC) of weapon systems and an inaccurate budget put in place. An inaccurate estimate of O&S costs lead to budgeting problems and creates future budget issues. This study begins an exploration of CGAI and attempts to measure the relationship of the cost growth to unaccounted increases in raw material cost. Specifically, we evaluate CGAI through an analysis of raw material costs from a period of 2000 to 2012 for Air Force aircraft. Raw material costs ideally should only be affected by inflation, and thus any cost growth beyond inflation indicates a problem. A better understanding of inflation-adjusted cost growth provides understanding why O&S cost continues to increase beyond the rate of inflation

    Exploring mental health treatment for female veterans in the US : assessing the influences on female veterans in selection of treatment location, comparing VA and non-VA settings

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    The purpose of this quantitative survey based study was to learn why women veterans choose VA versus non-VA mental health treatment when they need care. The study was designed to gain insight into choices that women veterans make when selecting mental health care treatment centers, and what motivates them in this choice. Women cited a number of barriers to treatment, particularly regarding accessing treatment through the VA. These barriers included limited appointment times, high turnover of providers, insufficient numbers of veterans and female veterans as providers, and feeling uncomfortable in the treatment environment
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