360 research outputs found
Low speed testing of the inlets designed for a tamden-fan V/STOL nacelle
An approximately 0.25 scale model of a tandem fan nacelle, designed for a subsonic V/STOL aircraft, was tested in a Lewis wind tunnel. Model variables included long and short aft inlet cowls and the addition of exterior strakes to the short inlet cowl. Inlet pressure recoveries and distortion were measured at pitch angles to 40 deg and at combinations of pitch and yaw to 30 deg. Airspeeds covered a range to 135 knots (69 m/sec). The short aft inlet with added strakes had the best aerodynamic performance and is considered suitable for the intended V/STOL application
Additional testing of the inlets designed for a tandem fan V/STOL nacelle
The wind tunnel testing of a scale model of a tandem fan nacelle designed for a type (subsonic cruise) V/STOL aircraft configuration is discussed. The performance for the isolated front inlet and for the combined front and aft inlets is reported. Model variables include front and aft inlets with aft inlet variations of short and long aft inlet cowls, with a shaft simulator and diffuser vortex generators, cowl lip fillets, and nacelle strakes. Inlet pressure recovery, distortion, and inlet angle-to-attack separation limits were evaluated at tunnel velocity from 0 to 240 knots, angles-of-attack from -10 to +40 degrees and inlet flow rates corresponding to throat Mach number from 0.0 to 0.6. Combined nacelle pitch and yaw runs up to 30 deg. were also made
Misanthropic Person Memory when the Need to Self-Enhance is Absent
This research examined the role that the removal of the need or ability to self-enhance can play in the misanthropic processing of attributed behavioral information (i.e., remembering best negative, internally attributed behaviors and positive externally attributed behaviors). Experiment 1demonstrated that removing a personâs need to self-enhance by increasing his or her self-esteem eliminated misanthropic memory, whereas misanthropy was preserved for control participants and perceivers who had experienced a decrease in self-esteem. Furthermore, controlling for participantsâ self-evaluations eliminated the memory pattern differences between the two experimental conditions. Experiment 2 demonstrated that canceling the ability to self-enhance by having perceivers form an impression of themselves eliminated the misanthropy effect. However, the misanthropy effect was replicated when perceivers learned about an unknown other. The results were discussed with regard to the situations and factors that can increase or reduce the need to self-enhance and their implications for social information processing.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68679/2/10.1177_0146167299025002011.pd
âI h 8 uâ: Findings from a five-year study of text and e-mail bullying
Copyright @ 2010 British Educational Research Association. The final version of this article is available at the link below.This study charts reports of nasty or threatening text and e-mail messages received by students in academic years 7 and 8 (11-13 years of age) attending 13 secondary schools in the North of England between 2002-2006. Annual surveys were undertaken on behalf of the local education authority (LEA) to monitor bullying. Results indicated that, over five years, the number of pupils receiving one or more nasty or threatening text messages or e-mails increased significantly, particularly among girls. However, receipt of frequent nasty or threatening text and e-mail messages remained relatively stable. For boys, being a victim of direct-physical bullying was associated with receiving nasty or threatening text and e-mail messages; for girls it was being unpopular among peers. Boys received more hate-related messages and girls were primarily the victims of name-calling, Findings are discussed with respect to theoretical and policy developments, and recommendations for future research are offered
Optimal Signal Processing of Frequency-Stepped CW Radar Data
An optimal signal processing algorithm is derived for estimating the time delay and amplitude of each scatterer reflection using a frequency-stepped CW system. The channel is assumed to be composed of abrupt changes in the reflection coefficient profile. The optimization technique is intended to maximize the target range resolution achievable from any set of frequency-stepped CW radar measurements made in such an environment. The algorithm is composed of an iterative two-step procedure. First, the amplitudes of the echoes are optimized by solving an overdetermined least squares set of equations. Then, a nonlinear objective function is scanned in an organized fashion to find its global minimum. The result is a set of echo strengths and time delay estimates. Although this paper addresses the specific problem of resolving the time delay between the first two echoes, the derivation is general in the number of echoes. Performance of the optimization approach is illustrated using measured data obtained from an HP-X510 network analyzer. It is demonstrated that the optimization approach offers a significant resolution enhancement over the standard processing approach that employs an IFFT. Degradation in the performance of the algorithm due to suboptimal model order selection and the effects of additive white Gaussion noise are addressed
Long-Wavelength Instability in Surface-Tension-Driven Benard Convection
Laboratory studies reveal a deformational instability that leads to a drained
region (dry spot) in an initially flat liquid layer (with a free upper surface)
heated uniformly from below. This long-wavelength instability supplants
hexagonal convection cells as the primary instability in viscous liquid layers
that are sufficiently thin or are in microgravity. The instability occurs at a
temperature gradient 34% smaller than predicted by linear stability theory.
Numerical simulations show a drained region qualitatively similar to that seen
in the experiment.Comment: 4 pages. The RevTeX file has a macro allowing various styles. The
appropriate style is "mypprint" which is the defaul
Herschel observations of the Herbig-Haro objects HH52-54
We are aiming at the observational estimation of the relative contribution to
the cooling by CO and H2O, as this provides decisive information for the
understanding of the oxygen chemistry behind interstellar shock waves. Methods.
The high sensitivity of HIFI, in combination with its high spectral resolution
capability, allows us to trace the H2O outflow wings at unprecedented
signal-to-noise. From the observation of spectrally resolved H2O and CO lines
in the HH52-54 system, both from space and from ground, we arrive at the
spatial and velocity distribution of the molecular outflow gas. Solving the
statistical equilibrium and non-LTE radiative transfer equations provides us
with estimates of the physical parameters of this gas, including the cooling
rate ratios of the species. The radiative transfer is based on an ALI code,
where we use the fact that variable shock strengths, distributed along the
front, are naturally implied by a curved surface. Based on observations of CO
and H2O spectral lines, we conclude that the emission is confined to the HH54
region. The quantitative analysis of our observations favours a ratio of the
CO-to-H2O-cooling-rate >> 1. From the best-fit model to the CO emission, we
arrive at an H2O abundance close to 1e-5. The line profiles exhibit two
components, one of which is triangular and another, which is a superposed,
additional feature. This additional feature likely originates from a region
smaller than the beam where the ortho-water abundance is smaller than in the
quiescent gas. Comparison with recent shock models indicate that a planar shock
can not easily explain the observed line strengths and triangular line
profiles.We conclude that the geometry can play an important role. Although
abundances support a scenario where J-type shocks are present, higher cooling
rate ratios than predicted by these type of shocks are derived.Comment: Accepted for publication in A&
GM 2-4 - a signpost for low and intermediate mass star formation
We present a multi-wavelength study of the region towards the GM 2-4 nebula
and the nearby source IRAS 05373+2340. Our near-infrared H2 1-0 S(1) line
observations reveal various shock-excited features which are part of several
bipolar outflows. We identify candidates for the driving sources of the
outflows from a comparison of the multi-waveband archival data-sets and SED
modelling. The SED spectral slope (\alpha(IRAC)) for all the protostars in the
field was then compared with the visual extinction map. This comparison
suggests that star formation is progressing from NE to SW across this region
Internet-based Self-Assessment after the Tsunami: lessons learned
BACKGROUND: In the aftermath of the Tsunami disaster in 2004, an online psychological self-assessment (ONSET) was developed and made available by the University of Zurich in order to provide an online screening instrument for Tsunami victims to test if they were traumatized and in need of mental health care. The objective of the study was to report the lessons learnt that were made using an Internet-based, self-screening instrument after a large-scale disaster and to discuss its outreach and usefulness.
METHODS: Users of the online self-assessment decided after finishing the procedure whether their dataset could be used for quality control and scientific evaluation Their answers were stored anonymously only if they consented (which was the case in 88% of the sample), stratified analyses according to level of exposure were conducted.
RESULTS: A total of 2,914 adult users gave their consent for analysis of the screenings. Almost three quarter of the sample filled out the ONSET questionnaire within the first four weeks. Forty-one percent of the users reported direct exposure to the Tsunami disaster. Users who were injured by the Tsunami and users who reported dead or injured family members showed the highest degree of PTSD symptoms.
CONCLUSION: ONSET was used by a large number of subjects who thought to be affected by the catastrophe in order to help them decide if they needed to see a mental health professional. Furthermore, men more frequently accessed the instrument than women, indicating that Internet-based testing facilitates reaching out to a different group of people than "ordinary" public mental health strategies
Design and development of a complex narrative intervention delivered by text messages to reduce binge drinking among socially disadvantaged men
Background:
Socially disadvantaged men are at high risk of suffering from alcohol-related harm. Disadvantaged groups are less likely to engage with health promotion. There is a need for interventions that reach large numbers at low cost and which promote high levels of engagement with the behaviour change process. The aim of this study was to design a theoretically and empirically based text message intervention to reduce binge drinking by socially disadvantaged men.
Results:
Following MRC guidance, the intervention was developed in four stages. Stage 1 developed a detailed behaviour change strategy based on existing literature and theory from several areas. These included the psychological theory that would underpin the intervention, alcohol brief interventions, text message interventions, effective behaviour change techniques, narratives in behaviour change interventions and communication theory. In addition, formative research was carried out. A logic model was developed to depict the pathways between intervention inputs, processes and outcomes for behaviour change. Stage 2 created a narrative which illustrated and modelled key steps in the strategy. Stage 3 rendered the intervention into a series of text messages and ensured that appropriate behavioural change techniques were incorporated. Stage 4 revised the messages to ensure comprehensive coverage of the behaviour change strategy and coherence of the narrative. It also piloted the intervention and made final revisions to it.
Conclusions:
The structured, systematic approach to design created a narrative intervention which had a strong theoretical and empirical basis. The use of a narrative helped make the intervention realistic and allowed key behaviour change techniques to be modelled by characters. The narrative was intended to promote engagement with the intervention. The intervention was rendered into a series of short text messages, and subsequent piloting showed they were acceptable in the target group. Delivery of an intervention by text message offers a low-cost, low-demand method that can reach large numbers of people. This approach provides a framework for the design of behaviour change interventions which could be used for interventions to tackle other health behaviours
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