6,633 research outputs found
Stochastic compartmental analysis - Some applications and examples of estimation in a pulse labelled system
Stochastic compartmental analysis with examples of estimation in pulse labelled syste
Effects of three different biochars on aggregate stability, organic carbon mobility and micronutrient bioavailability
Previous studies have demonstrated both beneficial and detrimental effects on soil properties from biochar incorporation. Several biochars, with different feedstock origins, were evaluated for their effectiveness at improving soil quality of a sandy agricultural soil. A pot trial was used to investigate aggregate stability and microbial activity, pore water trace element mobility and micronutrient concentrations in grain of spring wheat after incorporation of three biochars. The feedstocks for biochar production were selected because they were established UK waste products, namely oversize woody material from green waste composting facilities, and rhododendron and soft wood material from forest clearance operations. Biochars were incorporated into the soil at a rate of 5% v/v. Aggregate stability was improved following addition of oversize biochar whilst microbial activity increased in all treatments. Dissolved organic carbon (DOC) concentrations in soil pore water from biochar-treated soils were raised, whilst micronutrient concentrations in wheat grain grown in the treated soils were significantly reduced. It was concluded that incorporation of biochar to temperate agricultural soils requires caution as it may result in reductions of essential grain micronutrients required for human health, whilst the effect on aggregate stability may be linked to organic carbon functional groups on biochar surfaces and labile carbon released from the char into the soil system
Friction Stir Weld Tooling Development for Application on the 2195 Al-Cu-Li Space Transportation System External Tank
Friction Stir Welding (FSW) is a new and innovative solid-state joining process which can be applied to difficult-to- weld aluminum alloys. However, the large forces involved with the process have posed a production tooling challenge. Lockheed Martin Michoud Space Systems has overcome many of these challenges on the Super Lightweight External Tank (ET) program. Utilizing Aluminum-Copper-Lithium alloy 2195 in the form of plate and extrusions, investigations of FSW process parameters have been completed. Major loading mechanisms are discussed in conjunction with deflection measurements. Since the ET program is a cryogenic application, a brief comparison of cryogenic material properties with room temperature material properties is offered for both FSW and fusion welds. Finally, a new approach to controlling the FSW process from a load perspective is introduced. Emphasis will be put on tooling development, as well as the impact of tooling design and philosophy on Friction Stir Weld success probability
The Effects of Slots and Flaps on Lateral Control of a Low-wing Monoplane as Determined in Flight
This paper presents the results of flight tests made to determine the effect of slots and flaps on the lateral control of a low-wing monoplane. Maximum angular accelerations in roll and yaw produced by sudden application of the ailerons and maximum accelerations in yaw produced by sudden application of the rudder during gliding flight were recorded for the following wing arrangements: (a) no auxiliary device; (b) full-span slots; (c) plain flaps; (d) flaps and full-span slots; (e) wing-tip slots. Rolling- and yawing-moment coefficients were derived from the accelerations. The full span slots and the flaps each had about the same influence on the aileron rolling moments. At values of the lift coefficient obtainable with the plain wing, the effect of these devices was negligible. At the higher lift coefficients obtainable with these devices, the rolling-moment coefficients increased slightly but, despite this increase, the aileron effectiveness progressively decreased with increasing lift coefficient, owing to the corresponding reduction in air speed. In the range covered by the tests, the effectiveness of the controls was appreciably reduced by the wing-tip slots. The adverse yawing moment of the ailerons experienced at the large lift coefficients obtained with the flaps was appreciably less than at similar lift coefficients obtained with either full-span or wing-tip slots. The yawing moments produced by the rudder were only slightly affected by the use of the auxiliary devices. The airplane was found to be laterally unstable with all combinations tested. Because of the angular velocities acquired in the time taken to deflect the ailerons the rolling moments recorded in flight were only about two thirds the values that would have been obtained with the wing restrained as in wind-tunnel tests
Tracking sand-fairways through a deformed turbidite system : the Numidian (Miocene) of Central Sicily, Italy
The research presented here is funded by BG Group in partnership with CNPq-Brazil (National Council for Scientific and Technological Development). Rosanna Maniscalco acknowledges a FIR 2014 grant awarded from the University of Catania. We thank Christian Haug Eide, David Hodgson and Enrico Tavarnelli for constructive and thorough reviews on an earlier draft that have greatly improved this contribution.Peer reviewedPublisher PD
Stories tell us? Political narrative, demes, and the transmission of knowledge through culture
This paper compares two institutions of storytelling, mainstream national narratives and self-represented digital storytelling. It considers the centenary of World War 1, especially the Gallipoli campaign (1915) and its role in forming Australian ‘national character’. Using the new approach of cultural science, it investigates storytelling as a means by which cultures make and bind groups or ‘demes’. It finds that that demic (group-made) knowledge trumps individual experience, and that self-representation (digital storytelling) tends to copy the national narrative, even when the latter is known not to be true. The paper discusses the importance of culture in the creation of knowledge, arguing that if the radical potential of digital storytelling is to be understood – and realised – then a systems (as opposed to behavioural) approach to communication is necessary. Without a new model of knowledge, it seems we are stuck with repetition of the same old story
Moving Forward 21st Century Pathways to Strengthen the Ocean Science Workforce Through Graduate Education and Professional Development
The scope of emerging national and international ocean-related issues facing society demands that we develop broad perspectives on graduate education and training in the ocean sciences. A multifaceted ocean workforce and new kinds of intellectual partnerships are needed to address ocean science research priorities, strengthen our understanding of coupled human-natural ocean systems, engage and inform public policy and management decision making, and increase ocean literacy. Alumni from graduate programs in ocean sciences are following diverse career paths in academia, government, nongovernmental organizations, and industry, and thus can inform us about the diverse skills needed to succeed. The ocean science academic community should build on its current strengths (e.g., multidisciplinary and multi-institutional research and education, international partnerships), and capitalize on what some might view as limitations (e.g., remote, yet inviting, coastal campuses, diversity of ocean science programs), to become an incubator of innovation that will advance the field and strengthen graduate education and training. Partnerships within and among institutions with ocean-related programs, and with professional societies, employers, and others, can help us provide cutting-edge, relevant academic options, facilitate professional development, and proactively position graduates for career paths that reflect and address important societal needs
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