347 research outputs found

    Automation addiction - the unintended consequences of automation addiction for aviation safety

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    The human is the weakest link in the safety chain BUT, this must be seen against the backdrop that man was not designed to fly. The fickleness of human judgement, the under-developed psychomotor skills to handle an aircraft about all axes, cognitive dissonance and inconsistent decision making, have all contributed to accident statistics worldwide. The conscious decision by aircraft designers to embody innovative aerospace engineering technologies through automation and increased regulation, contributed to effectively remove the human from the control and decision making loop in flying large commercial jets and in the process, resulted in radical improvements to aviation safety. Sadly, despite such technological improvements, the human ‘operator-in-the-loop’ was left behind and relegated to the role of a systems monitor and systems manager without the equivalent increase in knowledge and training. The consequence thereof has been the psychological addiction to automation in which pilot’s handling skills and the ability of pilots to fully comprehend the effect of technological failures, albeit very rare, have regressed to such an extent, that automation addiction is now classified as the newest threat to commercial aircraft operations. Has this threat been identified and recognised as a technology paradox by aerospace engineers and pilots alike? Have design engineers understood the chasm between innovative engineering and the fickleness of man-machine interface? Have the test pilots and aerospace engineers understood the requirement to modulate the introduction of new technologies? Has the aerospace industry understood the need to accelerate pilot training regimens to deal with the pace of technology growth?Papers presented at the 36th Southern African Transport Conference, CSIR International Convention Centre, Pretoria, South Africa on 10-13 July 2017.Transportation research board of the national academie

    Monitoring of zincate pre-treatment of aluminium prior to electroless nickel plating

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    <p>Zincating is used as a pre-treatment for aluminium prior to electroless nickel deposition during preparation of magnetic computer memory discs. Four immersion zincating solutions were evaluated at 22°C using single step or double zincating followed by electroless nickel deposition from a high phosphorus hypophosphite bath at 90°C. The coating process was monitored by potential <i>vs.</i> time curves obtained under open-circuit conditions during zincating then electroless nickel plating. The surface morphology of the aluminium, at various stages, was imaged by scanning electron microscopy and atomic force microscopy. Zero resistance ammetry was used to record galvanic currents between the aluminium and an inert platinum counter electrode during zincating. This, together with potential-time measurements, provided simple and valuable methods for following the zincating process and subsequent electroless Ni plating. Double zincating enabled a shorter induction time for electroless Ni deposition and resulted in a more complete coverage of the surface by Zn.</p

    History of Being in Government Care Associated with Younger Age at Injection Initiation Among a Cohort of Street-involved Youth

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    Introduction and Aims: Compared to the general population of youth, health-related disparities experienced by youth exposed to the child welfare system are well documented. Amongst these vulnerabilities are elevated rates of substance use, including injection drug use; however, less is known about when these youth transition to this high-risk behaviour. We sought to assess whether having a history of government care is associated with initiating injection drug use before age 18. &nbsp; Design and Methods: Between September 2005 and May 2014, data were derived from the At-Risk Youth Study, a cohort of street-involved youth who use illicit drugs in Vancouver, Canada. Multivariable logistic regression analysis was employed to examine the relationship between early initiation of injection drug use and having a history of being in government care. &nbsp; Results: Among the 581 injecting street-involved youth included, 229 (39%) reported initiating injection drug use before 18 years of age. In multivariable analysis, despite controlling for a range of potential confounders, having a history of government care remained significantly associated with initiating injection drug use before age 18 (adjusted odds ratio = 1.69; 95% confidence interval: 1.15–2.48). &nbsp; Discussion and Conclusions: Youth with a history of being in government care were significantly more likely to initiate injection drug use before age 18 than street-involved youth without a history of being in care. These findings imply that youth in the child welfare system are at higher-risk and suggest interventions are needed to prevent transitions into high-risk substance use among this population

    Cooperativity in sandpiles: statistics of bridge geometries

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    Bridges form dynamically in granular media as a result of spatiotemporal inhomogeneities. We classify bridges as linear and complex, and analyse their geometrical characteristics. In particular, we find that the length distribution of linear bridges is exponential. We then turn to the analysis of the orientational distribution of linear bridges and find that, in three dimensions, they are {\it vertically diffusive but horizontally superdiffusive}; thus, when they exist, long linear bridges form `domes'. Our results are in good accord with Monte Carlo simulations of bridge structure; we make predictions for quantities that are experimentally accessible, and suggest that bridges are very closely related to force chains.Comment: 15 pages, 10 figures. Minor changes and update

    A ‘quiet revolution’? The impact of Training Schools on initial teacher training partnerships

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    This paper discusses the impact on initial teacher training of a new policy initiative in England: the introduction of Training Schools. First, the Training School project is set in context by exploring the evolution of a partnership approach to initial teacher training in England. Ways in which Training Schools represent a break with established practice are considered together with their implications for the dominant mode of partnership led by higher education institutions (HEIs). The capacity of Training Schools to achieve their own policy objectives is examined, especially their efficacy as a strategy for managing innovation and the dissemination of innovation. The paper ends by focusing on a particular Training School project which has adopted an unusual approach to its work and enquires whether this alternative approach could offer a more profitable way forward. During the course of the paper, five different models of partnership are considered: collaborative, complementary, HEI-led, school-led and partnership within a partnership

    Searching for the Slater Transition in the Pyrochlore Cd2_{2}Os2_{2}O7_{7} with Infrared Spectroscopy

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    Infrared reflectance measurements were made on the single crystal pyrochlore Cd2_{2}Os2_{2}O7_{7} in order to examine the transformations of the electronic structure and crystal lattice across the boundary of the metal insulator transition at TMIT=226KT_{MIT}=226K. All predicted IR active phonons are observed in the conductivity over all temperatures and the oscillator strength is found to be temperature independent. These results indicate that charge ordering plays only a minor role in the MIT and that the transition is strictly electronic in nature. The conductivity shows the clear opening of a gap with 2Δ=5.2kBTMIT2\Delta=5.2k_{B}T_{MIT}. The gap opens continuously, with a temperature dependence similar to that of BCS superconductors, and the gap edge having a distinct σ(ω)ω1/2\sigma(\omega)\thicksim\omega^{1/2} dependence. All of these observables support the suggestion of a Slater transition in Cd2_{2}% Os2_{2}O7_{7}.Comment: 4 pages, 4 figure

    Interpretation and application of carbon isotope ratios in freshwater diatom silica

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    Carbon incorporated into diatom frustule walls is protected from degradation enabling analysis for carbon isotope composition (δ13Cdiatom). This presents potential for tracing carbon cycles via a single photosynthetic host with well-constrained ecophysiology. Improved understanding of environmental processes controlling carbon delivery and assimilation is essential to interpret changes in freshwater δ13Cdiatom. Here relationships between water chemistry and δ13Cdiatom from contemporary regional data sets are investigated. Modern diatom and water samples were collected from river catchments within England and lake sediments from across Europe. The data suggest dissolved, biogenically produced carbon supplied proportionately to catchment productivity was critical in the rivers and soft water lakes. However, dissolved carbon from calcareous geology overwhelmed the carbon signature in hard water catchments. Both results demonstrate carbon source characteristics were the most important control on δ13Cdiatom, with a greater impact than productivity. Application of these principles was made to a sediment record from Lake Tanganyika. δ13Cdiatom co-varied with δ13Cbulk through the last glacial and Holocene. This suggests carbon supply was again dominant and exceeded authigenic demand. This first systematic evaluation of contemporary δ13Cdiatom controls demonstrates that diatoms have the potential to supply a record of carbon cycling through lake catchments from sediment records over millennial timescales

    The Roles of Tidal Evolution and Evaporative Mass Loss in the Origin of CoRoT-7 b

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    CoRoT-7 b is the first confirmed rocky exoplanet, but, with an orbital semi-major axis of 0.0172 AU, its origins may be unlike any rocky planet in our solar system. In this study, we consider the roles of tidal evolution and evaporative mass loss in CoRoT-7 b's history, which together have modified the planet's mass and orbit. If CoRoT-7 b has always been a rocky body, evaporation may have driven off almost half its original mass, but the mass loss may depend sensitively on the extent of tidal decay of its orbit. As tides caused CoRoT-7 b's orbit to decay, they brought the planet closer to its host star, thereby enhancing the mass loss rate. Such a large mass loss also suggests the possibility that CoRoT-7 b began as a gas giant planet and had its original atmosphere completely evaporated. In this case, we find that CoRoT-7 b's original mass probably didn't exceed 200 Earth masses (about 2/3 of a Jupiter mass). Tides raised on the host star by the planet may have significantly reduced the orbital semi-major axis, perhaps causing the planet to migrate through mean-motion resonances with the other planet in the system, CoRoT-7 c. The coupling between tidal evolution and mass loss may be important not only for CoRoT-7 b but also for other close-in exoplanets, and future studies of mass loss and orbital evolution may provide insight into the origin and fate of close-in planets, both rocky and gaseous.Comment: Accepted for publication by MNRAS on 2010 May

    Detection of betanodaviruses in apparently healthy aquarium fishes and invertebrates

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    Betanodaviruses are the causative agents of viral nervous necrosis (VNN) in cultured marine fish. A total of 237 apparently healthy aquarium fish, marine (65 species) and freshwater (12 species) fishes and marine invertebrates (4 species), which were stocked in a commercial aquarium in Seoul, South Korea, were collected from November 2005 to February 2006. The brains of the fish and other tissues of the invertebrates were examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and nested PCR to detect betanodavirus. Positive nested PCR results were obtained from the brains of 8 marine fish species (shrimp fish Aeoliscus strigatus, milkfish Chanos chanos, three spot damsel Dascyllus trimaculatus, Japanese anchovy Engraulis japonicus, pinecone fish Monocentris japonica, blue ribbon eel Rhinomuraena quaesita, look down fish Selene vomer, yellow tang Zebrasoma flavesenes), 1 marine invertebrate species (spiny lobster Pamulirus versicolor), and 2 freshwater fish species (South American leaf fish Monocirrhus polyacanthus and red piranha Pygocentrus nattereri). The detection rate in nested PCR was 11/237 (4.64%). These subclinically infected aquarium fish and invertebrates may constitute an inoculum source of betanodaviruses for cultured fishes in the Korean Peninsula
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