6,990 research outputs found

    Effect of length of Handley Page tip slots on the lateral-stability factor, damping in roll

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    Tests have been made in the NACA 7 by 10 foot wind tunnel on a Clark Y wing model equipped with various lengths of Handley Page slots extending inward from the wing tips. The slot lengths tested ranged from 20 to 100 per cent of the semi span. The effect of slot lengths on damping in roll was determined by means of both free-autorotation and forced-rotation test. In addition, the maximum lift coefficient was found with each slot length. The optimum length of slot for satisfactory damping in roll over a large range of angles of attack was found to be slightly over 50 per cent of the semispan for the form of slot tested

    Preliminary investigation of rolling moments obtained with spoilers on both slotted and plain wings

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    A wind-tunnel study has been made to determine the possibility of developing spoilers suitable for providing the lateral control for airplanes in place of the usual ailerons. The first tests were made on a model wing with a fixed tip slot, but when it was found that the effectiveness of the spoilers did not depend to any great extent on the slot, tests were made on a plain wing also. In both cases certain spoiler positions were found which were free from the usual adverse rolling moments with small deflections. Five different forms of spoiler were tested, the best ones being simple plates, either straight or slightly curved to fit the contour of the airfoil when not deflected. Sufficient rolling moment can probably be obtained from spoilers of reasonable size to provide satisfactory lateral control for certain types of airplanes

    Wind-tunnel research comparing lateral control devices, particularly at high angles of attack IX : tapered wings with ordinary ailerons

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    Tests were made with ordinary flap-type ailerons on two wings with different amounts of taper, one medium and the other extreme. On each wing both medium sized tapered ailerons and short wide tapered ailerons were tested

    Putting context into organizational intervention design:Using tailored questionnaires to measure initiatives for worker well-being

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    Realistic evaluation emphasizes the importance of exploring the mechanisms through which organizational interventions are effected. A well-known mechanism in organizational interventions is the screening process. Standardized questionnaires, in popular use, neither consider individuals’ appraisals of working conditions nor the specific context of the workplace. Screening with items tailored to intervention contexts may overcome the limitations of standardized questionnaires. In the present study, we evaluate an approach to develop a tailored questionnaire to measure employees’ appraisals of their specific working conditions. First, we interviewed 56 employees and 17 managers and, later, developed tailored items focused on the working conditions in a postal service. In follow-up interviews, we explore participants’ experiences with the tailored questionnaire, including the development of initiatives, compared to their previous experiences with the company´s annual attitude survey that used standardized scales. Results indicated that participants felt the tailored questionnaire highlighted issues that had previously been ignored, that initiatives were easier to develop due to its specificity, and that the feedback strategy was useful in prioritizing questionnaires. Overall, it can be concluded that tailored questionnaires may be appropriate for use in organizational intervention research and more broadly that evaluations of organizational interventions need to be contextually grounded

    Manipulating type-I and type-II Dirac polaritons in cavity-embedded honeycomb metasurfaces

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    Pseudorelativistic Dirac quasiparticles have emerged in a plethora of artificial graphene systems that mimic the underlying honeycomb symmetry of graphene. However, it is notoriously difficult to manipulate their properties without modifying the lattice structure. Here we theoretically investigate polaritons supported by honeycomb metasurfaces and, despite the trivial nature of the resonant elements, we unveil rich Dirac physics stemming from a non-trivial winding in the light-matter interaction. The metasurfaces simultaneously exhibit two distinct species of massless Dirac polaritons, namely type-I and type-II. By modifying only the photonic environment via an enclosing cavity, one can manipulate the location of the type-II Dirac points, leading to qualitatively different polariton phases. This enables one to alter the fundamental properties of the emergent Dirac polaritons while preserving the lattice structure - a unique scenario which has no analog in real or artificial graphene systems. Exploiting the photonic environment will thus give rise to unexplored Dirac physics at the subwavelength scale

    Radical Possibilities: Independent Media Production and Contemporary Reproductive Justice Activism

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    With the relentless attacks on healthcare access in 2011 and 2012, abortion-rights activists are looking to alternative strategies of mobilizing support. How can non-mainstream modes of reproductive justice organizing expand our ideas of art-making, protest, and resistance? Situated within specific historical and political legacies of independent feminist media-making, these activists work with diverse tools, mediums, and technologies to create their art. Alongside their projects, these activists strive to create reproductive justice communities of hope and strength, with a focus on community-oriented, grassroots, and localized protest methods

    Does influence beget autonomy? Clarifying the relationship between social and personal power

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    We iteratively develop and test a model to clarify the relationship between both high and low levels of social (influence) and personal (autonomy) power. A meta-analysis synthesising primary data (n = 298) and secondary data (n = 498) found that impaired personal power coincided with impaired social power, but not vice versa. Unexpectedly, elevated social power did not coincide with elevated personal power, suggesting that the association between influence and autonomy attenuates with increasing levels of power. Predictions arising from the meta-analysis and our revised theoretical model were supported in a subsequent study (n = 266). We discuss implications of these findings and avenues for future research

    Power moves beyond complementarity: A staring look elicits avoidance in low power perceivers and approach in high power perceivers

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    Sustained, direct eye-gaze — staring — is a powerful cue that elicits strong responses in many primate and non-primate species. The present research examined whether fleeting experiences of high and low power alter individuals’ spontaneous responses to the staring gaze of an onlooker. We report two experimental studies showing that sustained, direct gaze elicits spontaneous avoidance tendencies in low power perceivers, and spontaneous approach tendencies in high power perceivers. These effects emerged during interactions with different targets and when power was manipulated between-individuals (Study 1) and within-individuals (Study 2), thus attesting to a high degree of flexibility in perceivers’ reactions to gaze cues. Together, the present findings indicate that power can break the cycle of complementarity in individuals’ spontaneous responding: low power perceivers complement and move away from, and high power perceivers reciprocate and move towards, staring onlookers

    It Could Not Be Seen Because It Could Not Be Believed on June 30, 2013

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    Nineteen Prescott Fire Department, Granite Mountain Hot Shot (GMHS) wildland firefighters (WF) perished in Arizona in June 2013 Yarnell Hill Fire, an inexplicable wildland fire disaster. In complex wildland fires, sudden, dynamic changes in human factors and fire conditions can occur, thus mistakes can be unfortunately fatal. Individual and organizational faults regarding the predictable, puzzling, human failures that will result in future WF deaths are addressed. The GMHS were individually, then collectively fixated with abandoning their Safety Zone to reengage, committing themselves at the worst possible time, to relocate to another Safety Zone - a form of collective tunnel vision. Our goal is to provoke meaningful discussion toward improved wildland firefighter safety with practical solutions derived from a long-established wildland firefighter expertise/performance in a fatality-prone profession. Wildfire fatalities are unavoidable, hence these proposals, applied to ongoing training, can significantly contribute to other well-thought-out and validated measures to reduce them
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