13,629 research outputs found

    Civil helicopter wire strike assessment study. Volume 1: Findings and recommendations

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    Approximately 208 civil helicopter wire strike accidents for a ten year period 1970 to 1979 are analyzed. It is found that 83% of the wire strikes occurred during bright clear weather. Analysis of the accidents is organized under pilot, environment, and machine factors. Methods to reduce the wire strike accident rate are discussed, including detection/warning devices, identification of wire locations prior to flight, wire cutting devices, and implementation of training programs. The benefits to be gained by implementing accident avoidance methods are estimated to be fully justified by reduction in injury and death and reduction of aircraft damage and loss

    Collide and Conquer: Constraints on Simplified Dark Matter Models using Mono-X Collider Searches

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    The use of simplified models as a tool for interpreting dark matter collider searches has become increasingly prevalent, and while early Run II results are beginning to appear, we look to see what further information can be extracted from the Run I dataset. We consider three `standard' simplified models that couple quarks to fermionic singlet dark matter: an ss-channel vector mediator with vector or axial-vector couplings, and a tt-channel scalar mediator. Upper limits on the couplings are calculated and compared across three alternate channels, namely mono-jet, mono-ZZ (leptonic) and mono-W/ZW/Z (hadronic). The strongest limits are observed in the mono-jet channel, however the computational simplicity and absence of significant tt-channel model width effects in the mono-boson channels make these a straightforward and competitive alternative. We also include a comparison with relic density and direct detection constraints.Comment: 32 pages, 8 figures; v2: minor changes, conclusion unchanged, matches published versio

    Business and production solutions: closing loops and the circular economy

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    Traditional production frameworks and business models are now being challenged by alternatives that are informed by biology. The alternative paradigm, based on ecosystem models, argues that shifting from linear modes of production to a circular system can address material and energy efficiency by reducing the total volume of raw materials needed when manufacturing consumer products. This chapter introduces frameworks that apply closed-loop models at the product level namely; the Performance Economy, Cradle-to-CradleTM design, The Blue Economy and the Circular Economy. We discuss the historic development of these ideas and their main contributions. Through the use of examples we explore both practical challenges associated with realising circular strategies as well as their business model implications. We conclude by highlighting some of the theoretical challenges associated with adopting closed-loop models advocating for a critical approach to sustainable resource management which includes circular strategies as part of a toolbox of options

    Cell patterning on photolithographically defined parylene-C:SiO2 substrates

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    Cell patterning platforms support broad research goals, such as construction of predefined in vitro neuronal networks and the exploration of certain central aspects of cellular physiology. To easily combine cell patterning with Multi-Electrode Arrays (MEAs) and silicon-based ‘lab on a chip’ technologies, a microfabrication-compatible protocol is required. We describe a method that utilizes deposition of the polymer parylene-C on SiO(2 )wafers. Photolithography enables accurate and reliable patterning of parylene-C at micron-level resolution. Subsequent activation by immersion in fetal bovine serum (or another specific activation solution) results in a substrate in which cultured cells adhere to, or are repulsed by, parylene or SiO(2) regions respectively. This technique has allowed patterning of a broad range of cell types (including primary murine hippocampal cells, HEK 293 cell line, human neuron-like teratocarcinoma cell line, primary murine cerebellar granule cells, and primary human glioma-derived stem-like cells). Interestingly, however, the platform is not universal; reflecting the importance of cell-specific adhesion molecules. This cell patterning process is cost effective, reliable, and importantly can be incorporated into standard microfabrication (chip manufacturing) protocols, paving the way for integration of microelectronic technology

    Conceptual design of a floating support structure for an offshore vertical axis wind turbine : the lessons learnt

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    The design of floating support structures for wind turbines located offshore is a relatively new field. In contrast, the offshore oil and gas industry has been developing its technologies since the mid 1950s. However, the significantly and subtly different requirements of the offshore wind industry call for new methodologies. An Energy Technologies Institute (ETI) funded project called NOVA (for Novel Vertical Axis wind turbine) examined the feasibility of a large offshore vertical axis wind turbine in the 10-20 MW power range. The development of a case study for the NOVA project required a methodology to be developed to select the best configuration, based on the system dynamics. The design space has been investigated, ranking the possible options using a multi-criteria decision making (MCDM) method called TOPSIS. The best 'class' or design solution (based on water plane area stability) has been selected for a more detailed analysis. Two configurations are considered: a barge and a semi-submersible. The iterations to optimise and compare these two options are presented here, taking their dynamics and costs into account. The barge concept evolved to the 'triple doughnut-Miyagawa' concept, consisting of an annular cylindrical shape with an inner (to control the damping) and outer (to control added mass) bottom flat plates. The semi-submersible was optimised to obtain the best trade-off between dynamic behaviour and amount of material needed. The main conclusion is that the driving requirement is an acceptable response to wave action, not the ability to float or the ability to counteract the wind turbine overturning moment. A simple cost comparison is presented

    Copper and zinc nutrition experimental results.

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    Long term copper trial - Newdegate research station, 66N14. Copper, zinc and sulphur residual with DAP for wheat, 78WH66. Copper and zinc residual with dap 78Mo36. Zinc residual with high analysis n.p. fertiliser for wheat 80no31. Zinc residual with high analysis n.p. fertiliser for wheat 79me22, 79me23. Zinc residual with high analysis n.p. fertiliser for wheat 82mo8. Zinc, copper and sulphur residual with DAP, 781G27. Methods of copper application on new land, 85JE48. Evaluation of copper ore 85LG47. Zinc by nitrogen interaction, 85LG28. Zinc residual with DAP, 85LG29. Copper sulphate, copper chelate and copper oxychloride effectiveness for wheat, 85LG26. Zinc sulphate, zinc chelate sprays on wheat, 85LG

    Trace element nutrition

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    South Perth Long term copper trial - Newdegate Research Station – 66N14. Copper, zinc & sulphur residual with DAP for wheat – 78WH66. Copper and zinc residual with DAP – 78MO36. Zinc residual with high analysis N.P. fertilizer for wheat – 79ME22, 79ME23, 80MO8, 80NO31. Cereal responses to zinc Copper and nitrogen interactions on wheat varieties – 83GE2, 83WH1. Barley responses to drilled trace elements – 83BR4, 83BR5. Manganese on wheat – 82NO8. ESPERANCE Zinc residual with high analysis N.P. fertilizer for wheat – 83ES35. Methods of copper application on new land – 83LG6. Copper spray and nitrogen rate applications to wheat supplied with super, copper, zinc and molybdenum no. 1 – 83LG4. Copper sprays on wheat – 84LG3. Zinc sulphate, zinc chelate sprays on wheat – 84LG4. Nitrogen and Hoegrass@ on zinc nutrition of wheat grown on heavy land – 84LG30. Hoegrass@ on zinc nutrition of wheat varieties – 84LGX

    OFDM based WiFi Passive Sensing: a reference-free non-coherent approach

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    WiFi based passive sensing is attracting considerable interest in the scientific community for both research and commercial purposes. In this work, we aim at taking a step forward in an endeavor to achieve good sensing capabilities employing compact, low-cost, and stand-alone WiFi sensors. To this end, we resort to a reference-free non-coherent signal processing scheme, where the presence of a moving target echo is sought by detecting the amplitude modulation that it produces on the direct signal transmitted from the WiFi access point. We first validate the proposed strategy against simulated data, identifying advantages and limitations. Then, we apply the conceived solution on experimental data collected in a small outdoor area with the purpose of detecting a small cooperative drone
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