391 research outputs found

    The Transverse Particle Migration of Highly Filled Polymer Fluid Flow in a Pipe

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    Shear-induced particle migration was investigated by using a continuum diffusive -flux model for the creep flow of nickel powder filled polymers, which are viscous with shear-thinning characteristic. The model, together with flow equations, was employed for solving the non-Newtonian flow patterns and non-uniform particle concentration distribution of mono-modal suspensions in a pressure-driven tube flow. Particle volume fraction and velocity fields for the non-homogenous shear flow field were predicted for 40% particle volume fraction. The model captures the trends found in experimental investigations.Singapore-MIT Alliance (SMA

    Effects of a Structured Exercise Programme on Functional Balance in Visually Impaired Elderly Living in a Residential Setting

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    AbstractOne major priority for health care professionals is to minimize the risk of fall in the elderly population. While the quality of life of an individual is affected by fall accidents, management of post-fall disability in the elderly could be a huge economic burden to the society. Visually impaired elderly are at a higher risk of fall, because ā€œvisionā€, an important component contributing to balance, is disturbed. The aim of this study was to examine the effects of an exercise programme, which focused on improvement of the functional balance of visually impaired elderly. Visually impaired elderly residents were randomly assigned to either the exercise training or control group. A multidimensional, individually tailored exercise programme was introduced by physiotherapists to the exercise group for 12 weeks. Functional balance status reflected by the Berg Balance Scale, chair stand test, and timed up-and-go test assessed before and after the 12-week training programme was compared between the two groups. Results demonstrated a significant improvement in balance outcomes in the exercise group (p < 0.05) but not in the control group. The results of this study suggest that a physiotherapist-designed strengthening and balance-training programme can improve the functional balance status of visually impaired elderly

    The hydrolysis of geminal ethers: A kinetic appraisal of orthoesters and ketals

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    Ā© 2016 Repetto et al. A novel approach to protecting jet fuel against the effects of water contamination is predicated upon the coupling of the rapid hydrolysis reactions of lipophilic cyclic geminal ethers, with the concomitant production of a hydrophilic acyclic hydroxyester with de-icing properties (Fuel Dehydrating Icing Inhibitors - FDII). To this end, a kinetic appraisal of the hydrolysis reactions of representative geminal ethers was undertaken using a convenient surrogate for the fuel-water interface (D2 O/CD3 CN 1:4). We present here a library of acyclic and five/six-membered cyclic geminal ethers arranged according to their hydroxonium catalytic coefficients for hydrolysis, providing for the first time a framework for the development of FDII. A combination of 1H NMR, labelling and computational studies was used to assess the effects that may govern the observed relative rates of hydrolyses

    Wigner crystalization about Ī½\nu=3

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    We measure a resonance in the frequency dependence of the real diagonal conductivity, Re[Ļƒxx\sigma_{xx}], near integer filling factor, Ī½=3\nu=3. This resonance depends strongly on Ī½\nu, with peak frequency fpkā‰ˆ1.7f_{pk} \approx 1.7 GHz at Ī½=3.04\nu=3.04 or 2.92 close to integer Ī½\nu, but fpkā‰ˆf_{pk} \approx 600 MHz at Ī½=3.19\nu=3.19 or 2.82, the extremes of where the resonance is visible. The dependence of fpkf_{pk} upon nāˆ—n^*, the density of electrons in the partially filled level, is discussed and compared with similar measurments by Chen {\it et al.}\cite{yong} about Ī½=1\nu=1 and 2. We interpret the resonance as due to a pinned Wigner crystal phase with density nāˆ—n^* about the Ī½=3\nu=3 state.Comment: for proceedings of EP2DS-15 (Nara) to appear in Physica

    How Ontologies Can Help in an eMarketplace

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    Recently, ontologies have been developed in various business domains with the recent maturing of the Semantic Web technologies. However, ontology-related researches have largely focused on the facilitation of successful matchmaking but not much on tradersā€™ requirement elicitation and potential negotiations in e-marketplaces. Because ontology provides the key knowledge about the inter-relationships among the issues and alternatives of the tradersā€™ requirements, we show how to elicit trade requirements, alternatives, and tradeoff from an agreed ontology. This facilitates the whole business process of the e-marketplace, from matchmaking, recommendation, to negotiation. We further propose a novel methodology for the elicitation of dependencies among tradersā€™ requirements for the formulation of an effective decision plan. As a result, traders can have a better cognition of their requirements and the overall operations of the e-marketplace can be streamlined

    Angiopoietin-2 confers Atheroprotection in apoE-/- mice by inhibiting LDL oxidation via nitric oxide

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    Atherosclerosis is promoted by a combination of hypercholesterolemia and vascular inflammation. The function of Angiopoietin (Ang)-2, a key regulator of angiogenesis, in the maintenance of large vessels is unknown. A single systemic administration of Ang-2 adenovirus (AdAng-2) to apoE-/- mice fed a Western diet significantly reduced atherosclerotic lesion size 8 40%) and oxidized LDL and macrophage content of the plaques. These beneficial effects were abolished by the inhibition of nitric oxide synthase (NOS). In endothelial cells, endothelial NOS activation per se inhibited LDL oxidation and Ang-2 stimulated NO release in a Tie2-dependent manner to decrease LDL oxidation. These findings demonstrate a novel atheroprotective role for Ang-2 when endothelial cell function is compromised and suggest that growth factors, which stimulate NO release without inducing inflammation, could offer atheroprotection

    Hamiltonian Description of Composite Fermions: Magnetoexciton Dispersions

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    A microscopic Hamiltonian theory of the FQHE, developed by Shankar and myself based on the fermionic Chern-Simons approach, has recently been quite successful in calculating gaps in Fractional Quantum Hall states, and in predicting approximate scaling relations between the gaps of different fractions. I now apply this formalism towards computing magnetoexciton dispersions (including spin-flip dispersions) in the Ī½=1/3\nu=1/3, 2/5, and 3/7 gapped fractions, and find approximate agreement with numerical results. I also analyse the evolution of these dispersions with increasing sample thickness, modelled by a potential soft at high momenta. New results are obtained for instabilities as a function of thickness for 2/5 and 3/7, and it is shown that the spin-polarized 2/5 state, in contrast to the spin-polarized 1/3 state, cannot be described as a simple quantum ferromagnet.Comment: 18 pages, 18 encapsulated ps figure
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