201 research outputs found

    Biomass Scenarios, Present and Future: Evaluation of WEC's and Hall's Projections and Comparisons to IEW Poll Responses

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    Biomass, renewable plant or animal material used for energy consumption, is currently an important energy source in many countries and may have a more prominent future role globally, especially if greenhouse gas reduction programs are implemented. Quantitative forecasts are difficult because present and past biomass usage is not well documented, mainly because of the difficulty of measuring the amount of non-commercial usage. This document reports current usage estimates and offers possible scenarios for future usage in 2020 and beyond. The main sources of data are the two World Energy Council (WEC) (1992) reports 1992 Survey of Energy Responses, 16th Edition and Energy for Tomorrow's World, Hall's (1991) "Biomass Energy" in Energy Policy, and IEW Poll Responses from the January 1993 overview (Manne and Schrattenholzer, 1993). When looking at the available biomass literature, there are problems in performing accurate comparisons between different sources. Data for many regions were incomplete, and much of the available data was less useful than it could be due to lack of clarity. Problems and assumptions that were needed for any of the figures are listed, so that the reader can keep these imperfections in mind when viewing the projections

    Investigation of electrochemistry of high energy compounds in organic electrolytes, november 1, 1964 - april 30, 1965

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    Conversion by electrochemical process of chemical to electrical energy - high energy compounds in organic electrolytes and cathode material

    Fiber optic gas sensor

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    A gas sensor includes an in-fiber resonant wavelength device provided in a fiber core at a first location. The fiber propagates a sensing light and a power light. A layer of a material is attached to the fiber at the first location. The material is able to absorb the gas at a temperature dependent gas absorption rate. The power light is used to heat the material and increases the gas absorption rate, thereby increasing sensor performance, especially at low temperatures. Further, a method is described of flash heating the gas sensor to absorb more of the gas, allowing the sensor to cool, thereby locking in the gas content of the sensor material, and taking the difference between the starting and ending resonant wavelengths as an indication of the concentration of the gas in the ambient atmosphere

    Preparing the foundations for video-based, practice-placement support: establishing the role from a students’ perspective

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    Currently, many placement-based health programme students within the UK are supported through face-to-face visits from university staff. Whilst cited in literature as being of value, the face-to-face nature of this contact is not supported. Alternatives including video-based communications methods offer the potential for cost effective, environmentally responsible support. However, in order to establish the fitness for purpose of alternative approaches, the content and purpose of current support needs to be understood. This project aimed to investigate student perceptions of the ideal content and purpose of clinical support visits, and alternatives to the current face-to-face approach. Fifty-six Physiotherapy undergraduate students responded to questionnaires with a further nine participating in a follow-up focus group. Participants emphasised the value of the visit in guiding learning, ensuring progression and resolving arising issues, and highlighted concerns over alternative approaches. Focus group participants discussed the importance of personal and professional confidence in directing requirements for support, and went on to propose a menu of options for methods of communication.Whilst limited in some applications, video technologies may be one of the options. Overall, however, this project supports the need for consideration of individualised learning journeys within curriculum planning

    Distributed hydrogen sensing using in-fiber Rayleigh scattering

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    This letter reports a fully distributed hydrogen sensing technique using Rayleigh backscattering in palladium (Pd) and copper (Cu) coated optical fiber. The local in-fiber strain changes due to Pd hydrogen absorptions are interrogated spatially resolved optical frequency domain reflectrometry measurements of the Rayleigh signals. Electrical power is used to induce heating in the Pd coating, which accelerates both the hydrogen response and the sensor recycling. This technique promises an inexpensive and truly distributed fiber solution for continuous hydrogen leak detection with centimeter spatial resolution at room and low temperatures. © 2012 American Institute of Physics

    Flexible Cognitive Strategies during Motor Learning

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    Visuomotor rotation tasks have proven to be a powerful tool to study adaptation of the motor system. While adaptation in such tasks is seemingly automatic and incremental, participants may gain knowledge of the perturbation and invoke a compensatory strategy. When provided with an explicit strategy to counteract a rotation, participants are initially very accurate, even without on-line feedback. Surprisingly, with further testing, the angle of their reaching movements drifts in the direction of the strategy, producing an increase in endpoint errors. This drift is attributed to the gradual adaptation of an internal model that operates independently from the strategy, even at the cost of task accuracy. Here we identify constraints that influence this process, allowing us to explore models of the interaction between strategic and implicit changes during visuomotor adaptation. When the adaptation phase was extended, participants eventually modified their strategy to offset the rise in endpoint errors. Moreover, when we removed visual markers that provided external landmarks to support a strategy, the degree of drift was sharply attenuated. These effects are accounted for by a setpoint state-space model in which a strategy is flexibly adjusted to offset performance errors arising from the implicit adaptation of an internal model. More generally, these results suggest that strategic processes may operate in many studies of visuomotor adaptation, with participants arriving at a synergy between a strategic plan and the effects of sensorimotor adaptation

    Motor primitives in space and time via targeted gain modulation in cortical networks

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    Motor cortex (M1) exhibits a rich repertoire of activities to support the generation of complex movements. Recent network models capture many qualitative aspects of M1 dynamics, but they can generate only a few distinct movements (all of the same duration). We demonstrate that simple modulation of neuronal input–output gains in recurrent neuronal network models with fixed connectivity can dramatically reorganize neuronal activity and consequently downstream muscle outputs. We show that a relatively small number of modulatory control units provide sufficient flexibility to adjust high-dimensional network activity using a simple reward-based learning rule. Furthermore, novel movements can be assembled from previously-learned primitives and we can separately change movement speed while preserving movement shape. Our results provide a new perspective on the role of modulatory systems in controlling recurrent cortical activity.Our work was supported by grants from the Wellcome Trust (TPV and JPS WT100000, 246 GH 202111/Z/16/Z) and the Engineering and Physical Sciences Research Council (JPS)
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