1,933 research outputs found

    ESTIMATION OF KNEE EXTENSION MOMENT CONSIDERING VELOCITY EFFECT AND MUSCLE ACTIVATION USING TENDON SLACK LENGTH OPTIMIZATION

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    This study presents a model to estimate knee extension moment considering muscle velocity effect and muscle activation. The muscle tendon force is very sensitive to the tendon slack length. To predict tendon slack length, exact muscle parameters of a human are needed. But it is difficult to measure all of the muscle parameters from human body. So we propose the algorithm which finds the tendon slack length of quadriceps for more accurate estimation of knee extension moment. Finally considering muscle velocity effect and muscle activation, knee extension moment is estimated. Algorithm was embodied by MATLAB optimization toolbox. And it is evaluated by using an experimental data

    Managing Climatic Risks to Combat Land Degradation and Enhance Food security: Key Information Needs

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    This paper discusses the key information needs to reduce the negative impacts of weather variability and climate change on land degradation and food security, and identifies the opportunities and barriers between the information and services needed. It suggests that vulnerability assessments based on a livelihood concept that includes climate information and key socio-economic variables can overcome the narrow focus of common one-dimensional vulnerability studies. Both current and future climatic risks can be managed better if there is appropriate policy and institutional support together with technological interventions to address the complexities of multiple risks that agriculture has to face. This would require effective partnerships among agencies dealing with meteorological and hydrological services, agricultural research, land degradation and food security issues. In addition a state-of-the-art infrastructure to measure, record, store and disseminate data on weather variables, and access to weather and seasonal climate forecasts at desired spatial and temporal scales would be needed

    Attempts to synthesise quaternary MAX phases (Zr,M)2AlC and Zr2(Al,A)C as a way to approach Zr2AlC

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    Despite having never been synthesized, the MAX phase Zr2AlC attracts a lot of interest owing to its foreseen properties. A possible way to circumvent this obstacle is to stabilize Zr2AlC by partially substituting one of its constituting elements. Here we report on attempts to synthesise quaternary MAX phases (Zr,M)2AlC and Zr2(Al,A)C where M = Cr, Ti or Mo and A = S, As, Sn, Sb and Pb. We were notably able to produce Zr2(Al0.2Sn0.8)C, Zr2(Al0.35Pb0.65)C, and Zr2(Al0.3Sb0.7)C, with the latter representing the first antimony-based MAX phase ever reported

    Visual Environmental Data on Soils and Land Use

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    End of Project ReportThis project was established to develop a computer based system to view, manipulate and store data on soils, environment and land use in electronic map form for environmental decision support. It was designed to produce new information, charts and maps by combining features from the captured data, and to develop networking systems to allow exchange of data with other Teagasc centres, local and national government and the EU. The current report presents maps and tabular data of particular relevance to the environment. It includes information and maps on the total stocking density of livestock in different parts of Ireland. This is relevant to the nutrient loadings that soils and the environment are subject to from normal farming operations. It also includes maps and tabular information on phosphorus and potassium levels in soils and the recommended manure and fertiliser application given by Teagasc for grassland and cropping on these soils. In addition, it also describes and illustrates with tables and maps, a computerised programming approach for mapping phosphorus and potassium levels in soils at a detailed level by using the farmer’s address to locate samples at townland or DED level.European Union Structural Funding (EAGGF

    Comparison of the Electronic Structures of Two Non-cuprate Layered Transition Metal Oxide Superconductors

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    Comparison is made of the electronic structure of the little-studied layered transition metal oxide LiNbO2_2 with that of Nax_xCoO2_2, which has attracted tremendous interest since superconductivity was discovered in its hydrate. Although the active transition metal dd states are quite different due to different crystal fields and band filling, both systems show a strong change of electronic structure with changes in the distance between the transition metal ion layer and the oxygen layers. The niobate is unusual in having a large second-neighbor hopping amplitude, and a nearest neighbor hopping amplitude that is sensitive to the Nb-O separation. Lix_xNbO2_2 also presents the attractive simplicity of a single band triangular lattice system with variable carrier concentration that is superconducting.Comment: 5 pages, 3 embedded figures (Proceedings in third Hiroshima international workshop

    Preliminary Surface Study of Short Term Dissolution of UK High Level Waste Glass

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    AbstractA simulated Magnox glass which is Mg- and Al- rich was subjected to aqueous corrosion in static mode with deionised water at 90°C for 7 days and assessed using Cameca and Ion-ToF Secondary Ion Mass Spectrometry (SIMS). Depth profiling and ion imaging were done for both unleached and leached samples to reveal elemental distributions from the glass surface into the bulk. All the elements were distributed evenly for unleached glass. After leaching, depletion of alkali ions i.e. Na and Li was observed indicating the interdiffusion (ion exchange) process of the initial stage of leaching. Enrichment of Mg near the surface layer indicated precipitation of Mg-rich crystals at the near surface region

    Water vapour corrosion of rare earth monosilicates for environmental barrier coatings application

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    Water vapour corrosion resistance of five rare earth monosilicates Y2SiO5, Gd2SiO5, Er2SiO5, Yb2SiO5, and Lu2SiO5 was investigated during testing at 1350 ˚C for up to 166 h in static air with 90% water vapour. Four of the RE-silicates showed little weight gain (0.859 mg cm-2) after 166 h of exposure. Prior to testing the microstrucre consists of equiaxed grains of 4- 7 ± 0.4 µm. XRD analysis showed that after 50 h exposure to water vapour corrosion Y, Er, Yb and Lu-silicates had both mono and disilicates present on their surfaces as a result of the reaction between monosilicate and water vapour to form disilicate, while Gd-silicate has converted completely to G4.67Si3O13 making it less stable for environmental barrier coatings application. The microstructures of corroded Y, Er, Yb and Lu-silicates contain ridges and cracks, while that of Gd-silicate contains rounded grains suggesting melting along with striped contract grains

    Density Functional Theory of Magnetic Systems Revisited

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    The Hohenberg-Kohn theorem of density functional theory (DFT) for the case of electrons interacting with an external magnetic field (that couples to spin only) is examined in more detail than previously. A unexpected generalization is obtained: in certain cases (which include half metallic ferromagnets and magnetic insulators) the ground state, and hence the spin density matrix, is invariant for some non-zero range of a shift in uniform magnetic field. In such cases the ground state energy is not a functional of the spin density matrix alone. The energy gap in an insulator or a half metal is shown to be a ground state property of the N-electron system in magnetic DFT.Comment: Four pages, one figure. Submitted for publication, April 13, 2000 Revised, Sept 27, 200
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