9,994 research outputs found

    Implementing Rapid Prototyping Using CNC Machining (CNC-RP) Through a CAD/CAM Interface

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    This paper presents the methodology and implementation of a rapid machining system using a CAD/CAM interface. Rapid Prototyping using CNC Machining (CNC-RP) is a method that has been developed which enables automatic generation of process plans for a machined component. The challenge with CNC-RP is not the technical problems of material removal, but with all of the required setup, fixture and toolpath planning, which has previously required a skilled machinist. Through the use of advanced geometric algorithms, we have implemented an interface with a CAD/CAM system that allows true automatic NC code generation directly from a CAD model with no human interaction; a capability necessary for a practical rapid prototyping system.Mechanical Engineerin

    Level repulsion in hybrid photonic-plasmonic microresonators for enhanced biodetection

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    We theoretically analyse photonic-plasmonic coupling between a high Q whispering gallery mode (WGM) resonator and a core-shell nanoparticle. Blue and red shifts of WGM resonances are shown to arise from crossing of the photonic and plasmonic modes. Level repulsion in the hybrid system is further seen to enable sensitivity enhancements in WGM sensors: maximal when the two resonators are detuned by half the plasmon linewidth. Approximate bounds are given to quantify possible enhancements. Criteria for reactive vs. resistive coupling are also established

    Electricity Generation in Fiji: Assessing the Impact of Renewable Technologies on Costs and Financial Risk

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    In recent years, renewable energy technologies have been advocated in Fiji on the basis that they improve energy security and serve as a risk-mitigation measure against oil price volatility. Despite this, there have been few attempts to measure the impact of renewable technologies on energy security. That analysis is important if the benefits of renewable energy technologies in Fiji are to be adequately evaluated. This paper develops and applies a method for assessing the potential contribution of renewable technologies to the security of electricity supply in Fiji. The method is based on an application of portfolio theory, traditionally used in financial markets, to the electricity generation mix in Fiji. The results demonstrate the impact of different renewable technologies on both portfolio generation cost and risk for Fijian electricity grids.renewable energy technologies, energy policy, electricity sector, Fiji, oil prices, portfolio analysis, Pacific islands, Resource /Energy Economics and Policy,

    Signalling mechanisms of long term facilitation of breathing with intermittent hypoxia.

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    Intermittent hypoxia causes long-term facilitation (LTF) of respiratory motor nerve activity and ventilation, which manifests as a persistent increase over the normoxic baseline for an hour or more after the acute hypoxic ventilatory response. LTF is likely involved in sleep apnea, but its exact role is uncertain. Previously, LTF was defined as a serotonergic mechanism, but new evidence shows that multiple signaling pathways can elicit LTF. This raises new questions about the interactions between signaling pathways in different time domains of the hypoxic ventilatory response, which can no longer be defined simply in terms of neurochemical mechanisms

    Do Physicians Respond to Liability Standards?

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    In this paper, we explore the sensitivity in the clinical decisions of physicians to the standards of care expected of them under the law, drawing on the abandonment by states over time of rules holding physicians to standards determined by local customs and the contemporaneous adoption of national-standard rules. Using data on broad rates of surgical interventions at the county-by-year level from the Area Resource File, we find that local surgery rates converge towards national surgery rates upon the adoption of national-standard rules. Moreover, we find that these effects are more pronounced among rural counties
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