1,315 research outputs found
Design evaluation criteria for commercial STOL transports
Handling qualities criteria and operational performance margins have been determined for the landing phase of commercial short-takeoff-and-landing airplanes. The requirements are the result of a literature survey, analysis of areas found to be inadequately covered by current criteria, and a subsequent piloted simulator investigation of critical criteria requiring substantiation. Three complete simulator models were used, each describing the characteristics of a different high-lift system, the externally blown flap, the augmentor flap, and the internally blown flap. The proposed criteria are presented with substantiating discussions from currently available data or directly from the results of this simulation work where it is applicable
Estimation of unsteady lift on a pitching airfoil from wake velocity surveys
The results of a joint experimental and computational study on the flowfield over a periodically pitched NACA0012 airfoil, and the resultant lift variation, are reported in this paper. The lift variation over a cycle of oscillation, and hence the lift hysteresis loop, is estimated from the velocity distribution in the wake measured or computed for successive phases of the cycle. Experimentally, the estimated lift hysteresis loops are compared with available data from the literature as well as with limited force balance measurements. Computationally, the estimated lift variations are compared with the corresponding variation obtained from the surface pressure distribution. Four analytical formulations for the lift estimation from wake surveys are considered and relative successes of the four are discussed
Time-resolved optical/near-IR polarimetry of V404 Cyg during its 2015 outburst
We present optical and near-IR linear polarimetry of V404 Cyg during its 2015
outburst and in quiescence. We obtained time resolved r'-band polarimetry when
the source was in outburst, near-IR polarimetry when the source was near
quiescence and multiple wave-band optical polarimetry later in quiescence. The
optical to near-IR linear polarization spectrum can be described by
interstellar dust and an intrinsic variable component. The intrinsic optical
polarization, detected during the rise of one of the brightest flares of the
outburst, is variable, peaking at 4.5 per cent and decaying to 3.5 per cent. We
present several arguments that favour a synchrotron jet origin to this variable
polarization, with the optical emission originating close to the jet base. The
polarization flare occurs during the initial rise of a major radio flare event
that peaks later, and is consistent with a classically evolving synchrotron
flare from an ejection event. We conclude that the optical polarization flare
represents a jet launching event; the birth of a major ejection. For this event
we measure a rather stable polarization position angle of -9 degrees E of N,
implying that the magnetic field near the base of the jet is approximately
perpendicular to the jet axis. This may be due to the compression of magnetic
field lines in shocks in the accelerated plasma, resulting in a partially
ordered transverse field that have now been seen during the 2015 outburst. We
also find that this ejection occurred at a similar stage in the repetitive
cycles of flares.Comment: 9 pages, 5 figures, accepted for publication by MNRA
NASA Trapezoidal Wing Computations Including Transition and Advanced Turbulence Modeling
Flow about the NASA Trapezoidal Wing is computed with several turbulence models by using grids from the first High Lift Prediction Workshop in an effort to advance understanding of computational fluid dynamics modeling for this type of flowfield. Transition is accounted for in many of the computations. In particular, a recently-developed 4-equation transition model is utilized and works well overall. Accounting for transition tends to increase lift and decrease moment, which improves the agreement with experiment. Upper surface flap separation is reduced, and agreement with experimental surface pressures and velocity profiles is improved. The predicted shape of wakes from upstream elements is strongly influenced by grid resolution in regions above the main and flap elements. Turbulence model enhancements to account for rotation and curvature have the general effect of increasing lift and improving the resolution of the wing tip vortex as it convects downstream. However, none of the models improve the prediction of surface pressures near the wing tip, where more grid resolution is needed
Building nursing and midwifery leadership capacity in the Pacific
© 2016 International Council of Nurses Aim: The Australian Award Fellowship Program aimed to strengthen nursing and midwifery leadership and capacity in developing countries in the Pacific. Background: It is necessary to build an optimal global health workforce, and leadership and mentorship are central to this need. This is especially important in small island states such as the Pacific who have limited capacity and resources. Introduction: This health system strengthening program addressed quality improvement in education, through the mentorship of potential nursing and midwifery leaders in the South Pacific Region. Methods: Program participants between 2013 and 2015 were interviewed. Data were audio-taped, transcribed and analysed thematically using an inductive process. Results: Thirty-four nurses and midwives from 12 countries participated. There were four main themes arising from the data which were: having a country-wide objective, learning how to be a leader, negotiating barriers and having effective mentorship. Discussion: Our study showed that participants deemed their mentorship from country leaders highly valuable in relation to completing their projects, networking and role modelling. Similar projects are described. Limitations: The limitation of this study was its small size. There is a need to continue to build the momentum of the program and Fellows in each country in order to build regional networks. Conclusions and implications for nursing and midwifery: The Program has provided beneficial leadership education and mentorship for nurses and midwives from Pacific countries. It has provided a platform to develop quality improvement projects in line with national priorities. Implications for health policy: Global aid programs and the recipients of the program would benefit from comparable health strengthening approaches to nursing and midwifery in similar developing countries
Qualitative evaluation of a public-private partnership for reproductive health training in Papua New Guinea
© 2018 Thiessen J, Bagoi A, Homer C, Rumsey M. Introduction: The recent policy environment in both Papua New Guinea and Australia for partnering with private entities to address health issues has led to a public-private partnership (PPP) between the National Department of Health in Papua New Guinea, the Australian Government and the Oil Search Foundation. A reproductive health training unit was formed to provide health worker training in essential obstetric care and emergency obstetric care. This article provides a qualitative evaluation of the PPP, looking at facilitating features and barriers to the PPP's target of improving the competence of frontline health workers in obstetric care service provision in Papua New Guinea. Method: A qualitative methodology gathered data since the PPP's inception in 2012. A dataset of 85 interviews with partners and relevant stakeholders from across Papua New Guinea was analysed using thematic analysis. Results: Themes of facilitating features of the PPP were (1) understanding and agreeing with the national plan for PPPs and maternal and child health; (2) having strong champions, strong relationships and a formal decision-making body; and (3) creating autonomy and branding. Themes outlining the barriers to the PPP's effectiveness were (1) lacking governance framework creating confusion in decision making and roles and responsibilities; (2) differing institutional cultures and ownership struggles; and (3) lacking capacity within the institutes themselves, particularly the National Department of Health. Conclusion: The findings of this service provision case study confirm what has been found in other infrastructure-led PPPs. Further research into how to overcome power imbalances between partners in a PPP as well as setting up a governance framework in a dynamic environment could inform this growing area of collaboration between the private and public sectors
Recommended from our members
Neurophysiology of prospective memory in typical and atypical ageing
The ability to delay an intention is known as ‘prospective memory’ (PM) and underpins many day-to-day activities. The ubiquity of PM makes it essential for independent living in older adults. Research suggests that PM function declines as we age and may be further exacerbated with the development of mild cognitive impairment (MCI). To date, there has been no research examining the neurophysiology of PM in older adults with MCI. This thesis addresses a series of questions to help understand the neurophysiology of PM and how it may be affected by ageing and MCI: 1) Are there neurophysiological differences between highly salient PM cues and less salient PM cues? 2) Can the neurophysiological reorientation of attention be identified in PM tasks? 3) Are there behavioural and neurophysiological differences between young adults, older adults and older adults with MCI during PM tasks? 4) Are there behavioural and neurophysiological differences when maintaining a PM intention between young adults, older adults and older adults with MCI? 5) Can machine learning be used to understand spatiotemporal patterns of brain activity in response to PM between young adults, older adults and older adults with MCI? To answer these questions behavioural and time-locked electroencephalographic (EEG) responses were examined during PM tasks and were modelled with a machine learning method known as Spiking Neural Networks (SNN). Results suggest that: there are behavioural and neurophysiological differences between the PM cues and the neurophysiological reorientation of attention can be detected in PM tasks; older adults are not impaired in PM tasks possibly due to compensatory neural mechanisms; older adults with MCI may be impaired in some PM tasks, which may be due to deficits in attention and feelings of knowing; modelling PM with SNNs may offer useful ways of understanding spatiotemporal connectivity in PM and MCI
FUN3D and CFL3D Computations for the First High Lift Prediction Workshop
Two Reynolds-averaged Navier-Stokes codes were used to compute flow over the NASA Trapezoidal Wing at high lift conditions for the 1st AIAA CFD High Lift Prediction Workshop, held in Chicago in June 2010. The unstructured-grid code FUN3D and the structured-grid code CFL3D were applied to several different grid systems. The effects of code, grid system, turbulence model, viscous term treatment, and brackets were studied. The SST model on this configuration predicted lower lift than the Spalart-Allmaras model at high angles of attack; the Spalart-Allmaras model agreed better with experiment. Neglecting viscous cross-derivative terms caused poorer prediction in the wing tip vortex region. Output-based grid adaptation was applied to the unstructured-grid solutions. The adapted grids better resolved wake structures and reduced flap flow separation, which was also observed in uniform grid refinement studies. Limitations of the adaptation method as well as areas for future improvement were identified
A close-pair binary in a distant triple supermassive black-hole system
Galaxies are believed to evolve through merging, which should lead to
multiple supermassive black holes in some. There are four known triple black
hole systems, with the closest pair being 2.4 kiloparsecs apart (the third
component is more distant at 3 kiloparsecs), which is far from the
gravitational sphere of influence of a black hole with mass 10
M (about 100 parsecs). Previous searches for compact black hole systems
concluded that they were rare, with the tightest binary system having a
separation of 7 parsecs. Here we report observations of a triple black hole
system at redshift z=0.39, with the closest pair separated by 140
parsecs. The presence of the tight pair is imprinted onto the properties of the
large-scale radio jets, as a rotationally-symmetric helical modulation, which
provides a useful way to search for other tight pairs without needing extremely
high resolution observations. As we found this tight pair after searching only
six galaxies, we conclude that tight pairs are more common than hitherto
believed, which is an important observational constraint for low-frequency
gravitational wave experiments.Comment: 21 pages, 6 figures. Published online by Nature on 25 June 2014.
Extremely minor differences with published version exis
Skeletal Muscle PGC-1β Signaling is Sufficient to Drive an Endurance Exercise Phenotype and to Counteract Components of Detraining in Mice
Peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α and -1β serve as master transcriptional regulators of muscle mitochondrial functional capacity and are capable of enhancing muscle endurance when overexpressed in mice. We sought to determine whether muscle-specific transgenic overexpression of PGC-1β affects the detraining response following endurance training. First, we established and validated a mouse exercise-training-detraining protocol. Second, using multiple physiological and gene expression end points, we found that PGC-1β overexpression in skeletal muscle of sedentary mice fully recapitulated the training response. Lastly, PGC-1β overexpression during the detraining period resulted in partial prevention of the detraining response. Specifically, an increase in the plateau at which O2 uptake (V̇o2) did not change from baseline with increasing treadmill speed [peak V̇o2 (ΔV̇o2max)] was maintained in trained mice with PGC-1β overexpression in muscle 6 wk after cessation of training. However, other detraining responses, including changes in running performance and in situ half relaxation time (a measure of contractility), were not affected by PGC-1β overexpression. We conclude that while activation of muscle PGC-1β is sufficient to drive the complete endurance phenotype in sedentary mice, it only partially prevents the detraining response following exercise training, suggesting that the process of endurance detraining involves mechanisms beyond the reversal of muscle autonomous mechanisms involved in endurance fitness. In addition, the protocol described here should be useful for assessing early-stage proof-of-concept interventions in preclinical models of muscle disuse atrophy
- …