1,986 research outputs found

    Advanced high temperature instrument for hot section research applications

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    Programs to develop research instrumentation for use in turbine engine hot sections are described. These programs were initiated to provide improved measurements capability as support for a multidisciplinary effort to establish technology leading to improved hot section durability. Specific measurement systems described here include heat flux sensors, a dynamic gas temperature measuring system, laser anemometry for hot section applications, an optical system for viewing the interior of a combustor during operation, thin film sensors for surface temperature and strain measurements, and high temperature strain measuring systems. The state of development of these sensors and measuring systems is described, and, in some cases, examples of measurements made with these instruments are shown. Work done at the NASA Lewis Research Center and at various contract and grant facilities is covered

    Measuring unsteady pressure on rotating compressor blades

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    Miniature semiconductor strain gage pressure transducers mounted in several arrangements were studied. Both surface mountings and recessed flush mountings were tested. Test parameters included mounting arrangement, blade material, temperature, local strain in the acceleration normal to the transducer diaphragm, centripetal acceleration, and pressure. Test results show no failures of transducers or mountings and indicate an uncertainty of unsteady pressure measurement of approximately + or - 6 percent + 0.1 kPa for a typical application. Two configurations were used on a rotating fan flutter program. Examples of transducer data and correction factors are presented

    Master and Action Plans Concept: Wastewater Management Norwegian methodology Illustrated with a Case Study for the Bystra River Catchment, Poland

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    The project: "Strategy for integrated Water Supply, Wastewater Treatment and Disposal System for Small Communes in Poland: Case study - Master and Action Plans (MaAP) for the Bystra river catchment", is a part of the Programme of Bilateral CO-operation between the Norwegian Ministry of Environment and the Ministry of Environmental Protection, Natural Resources and Forestry in Poland. It has been implemented by the Norwegian Institute for Water Research (NIVA) and has been funded by the Norwegian Pollution Control Authority (SFT). The Institute of Environmental Protection (IOS) in Poland has been responsible for the co-ordination in Poland, sponsored by the National Foundation for Environmental Protection and Water Management. Management. This report presents the principles of the Norwegian methodology for making master plans for wastewater management, based on the guidelines from SFT. The methodology is illustrated with a case for the Bystra river catchment in Poland

    Strategy for Integrated Water Supply, Wastewater Treatment and Disposal Systems for Small Communes in Poland Case study - Master and Action Plans (MaAP) for the Bystra River Catchment

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    This report is the final report of the project: "Strategy for integrated Water Supply, Wastewater Treatment and Disposal System for Small Communes in Poland: Case study - Master and Action Plans (MaAP) for the Bystra river catchment". The project is part of the Programme of Bilateral Co-operation between the Norwegian Ministry of Environment and the Ministry of Environmental Protection, Natural Resources and Forestry in Poland. It has been implemented by the Norwegian Institute for Water Research (NIVA) and has been funded by the Norwegian Pollution Control Authority (SFT). The Institute of Environmental Protection (IOS) in Poland has been responsible for the co-ordination in Poland, sponsored by the National Foundation for Environmental Protection and Water Management. The project provides an input to the process of wastewater master planning methodology in Poland, presented as a case study for the Bystra river catchment, and based on Norwegian procedures. on Norwegian procedures. This report presents the main objectives, activities and conclusions of the project, as well as a short presentation of Norwegian experiences relevant to the project. Five report have been elaborated prior to this report, where the entire project development is described

    Space race functional responses

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    We derive functional responses under the assumption that predators and prey are engaged in a space race in which prey avoid patches with many predators and predators avoid patches with few or no prey. The resulting functional response models have a simple structure and include functions describing how the emigration of prey and predators depend on interspecific densities. As such, they provide a link between dispersal behaviors and community dynamics. The derived functional response is general but is here modeled in accordance with empirically documented emigration responses. We find that the prey emigration response to predators has stabilizing effects similar to that of the DeAngelis-Beddington functional response, and that the predator emigration response to prey has destabilizing effects similar to that of the Holling type II response. A stabiliy criterion describing the net effect of the two emigration responses on a Lotka-Volterra predator-prey system is presented. The winner of the space race (i.e. whether predators or prey are favoured) is determined by the relationship between the slopes of the species- migration responses. It is predicted that predators win the space race in poor habitats, where predator and prey densities are low, and that prey are more successful in richer habitats

    Recent advances in high temperature instrumentation for hot section applications

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    Programs to develop research instrumentation for use in turbine engine hot sections are described. These programs were initiated to provide improved measurements capability as support for a multidisciplinary effort to establish technolgy leading to improved hot section durability. Specific measurement systems described here include heat flux sensors, a dynamic gas temperature measuring system, laser anemometry for hot section applications, an optical system for viewing the interior of a combustor during operation, thin film sensors for surface temperature and strain measurements, and high temperature strain measuring systems. The paper describes the state of the development of these sensors and measuring systems and, in some cases, will show examples of measurements made with this instrumentation.The paper covers work done at the NASA Lewis Research Center and at various contract and grant facilities

    Scalable Quantum Networks: Congestion-Free Hierarchical Entanglement Routing with Error Correction

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    We introduce Quantum Tree Networks (QTN), an architecture for hierarchical multi-flow entanglement routing. The network design is a kk-ary tree where end nodes are situated on the leaves and routers at the internal nodes, with each node connected to kk nodes in the child layer. The channel length between nodes grows with a rate aka_k, increasing as one ascends from the leaf to the root node. This construction allows for congestion-free and error-corrected operation with qubit-per-node overhead to scale sublinearly with the number of end nodes, NN. The overhead for a kk-ary QTN scales as O(NlogkaklogkN)\mathcal{O}(N^{\log_k a_k} \cdot \log_k N) and is sublinear for all kk with minimal surface-covering end nodes. More specifically, the overhead of quarternary (k=4k=4) QTN is O(N0.25log4N)\sim \mathcal{O}(N^{0.25}\cdot\log_4 N). Alternatively, when end nodes are distributed over a square lattice, the quaternary tree routing gives the overhead O(Nlog4N)\sim \mathcal{O}(\sqrt{N}\cdot\log_4 N). Our network-level simulations demonstrate a size-independent threshold behavior of QTNs. Moreover, tree network routing avoids the necessity for intricate multi-path finding algorithms, streamlining the network operation. With these properties, the QTN architecture satisfies crucial requirements for scalable quantum networks.Comment: 13 pages, 5 figure

    First-principles method for high-QQ photonic crystal cavity mode calculations

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    We present a first-principles method to compute radiation properties of ultra-high quality factor photonic crystal cavities. Our Frequency-domain Approach for Radiation (FAR) can compute the far-field radiation pattern and quality factor of cavity modes 100\sim 100 times more rapidly than conventional finite-difference time domain calculations. It also provides a simple rule for engineering the cavity's far-field radiation pattern

    Geospatial supply-demand modeling of lignocellulosic biomass for electricity and biofuels in the European Union

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    Bioenergy can contribute to achieving European Union (EU) climate targets while mitigating impacts from current agricultural land use. A GIS-based modeling framework (1000 m resolution) is employed to match biomass supply (forest and agricultural residues, complemented by lignocellulosic energy crops where needed) with biomass demand for either electricity or bio-oil production on sites currently used for coal power in the EU-28, Norway, and Switzerland. The framework matches supply and demand based on minimizing the field-to-gate costs and is used to provide geographically explicit information on (i) plant-gate supply cost; (ii) CO2 savings; and (iii) potential mitigation opportunities for soil erosion, flooding, and eutrophication resulting from the introduction of energy crops on cropland. Converting all suitable coal power plants to biomass and assuming that biomass is sourced within a transport distance of 300 km, would produce an estimated 150 TW h biomass-derived electricity, using 1365 PJ biomass, including biomass from energy crops grown on 6 Mha. Using all existing coal power sites for bio-oil production in 100-MW pyrolysis units could produce 820 PJ of bio-oil, using 1260 PJ biomass, including biomass from energy crops grown on 1.8 Mha. Using biomass to generate electricity would correspond to an emissions reduction of 135 MtCO2, while using biomass to produce bio-oil to substitute for crude oil would correspond to a reduction of 59 MtCO2. In addition, energy crops can have a positive effect on soil organic carbon in most of the analyzed countries. The mitigation opportunities investigated range from marginal to high depending on location
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