14,194 research outputs found

    Man's transportation to space

    Get PDF
    Saturn i, saturn ib, and saturn v launch vehicle

    Understanding reflective practice: encouraging better student engagement. First person action inquiry

    Get PDF
    The purpose of this research project is to examine my own engagement with reflective practice in my capacity as teacher and practitioner. This process of examination aims to improve attention to reflective practice within the student nutritional therapist environment where I teach. Research was conducted using a first-person action approach, with data acquired via critical self-observation and non-inquisitorial involvement in work-based situations feeding into action-reflection cycles. Conclusions highlighted strengths and areas for development as teacher and practitioner which may impact on student engagement with reflective practice on the course. Wider staff training and improvement to the curriculum were also identified with actions and recommendations including the adoption of new reflective practice teaching methods, further training for staff, adjustments to personal reflective practices and curriculum-wide developments. The proposed dissemination of findings and outcomes more widely will be via the nutritional therapy regulatory body and amongst fellow training providers

    Afterglow lightcurves, viewing angle and the jet structure of gamma-ray bursts

    Full text link
    Gamma ray bursts are often modelled as jet-like outflows directed towards the observer; the cone angle of the jet is then commonly inferred from the time at which there is a steepening in the power-law decay of the afterglow. We consider an alternative model in which the jet has a beam pattern where the luminosity per unit solid angle (and perhaps also the initial Lorentz factor) decreases smoothly away from the axis, rather than having a well-defined cone angle within which the flow is uniform. We show that the break in the afterglow light curve then occurs at a time that depends on the viewing angle. Instead of implying a range of intrinsically different jets - some very narrow, and others with similar power spread over a wider cone - the data on afterglow breaks could be consistent with a standardized jet, viewed from different angles. We discuss the implication of this model for the luminosity function.Comment: Corrected typo in Eq. 1

    Adaptation of a general circulation model to ocean dynamics

    Get PDF
    A primitive-variable general circulation model of the ocean was formulated in which fast external gravity waves are suppressed with rigid-lid surface constraint pressires which also provide a means for simulating the effects of large-scale free-surface topography. The surface pressure method is simpler to apply than the conventional stream function models, and the resulting model can be applied to both global ocean and limited region situations. Strengths and weaknesses of the model are also presented

    Predictions for The Very Early Afterglow and The Optical Flash

    Full text link
    According to the internal-external shocks model for γ\gamma -ray bursts (GRBs), the GRB is produced by internal shocks within a relativistic flow while the afterglow is produced by external shocks with the ISM. We explore the early afterglow emission. For short GRBs the peak of the afterglow will be delayed, typically, by few dozens of seconds after the burst. For long GRBs the early afterglow emission will overlap the GRB signal. We calculate the expected spectrum and the light curves of the early afterglow in the optical, X-ray and γ\gamma -ray bands. These characteristics provide a way to discriminate between late internal shocks emission (part of the GRB) and the early afterglow signal. If such a delayed emission, with the characteristics of the early afterglow, will be detected it can be used both to prove the internal shock scenario as producing the GRB, as well as to measure the initial Lorentz factor of the relativistic flow. The reverse shock, at its peak, contains energy which is comparable to that of the GRB itself, but has a much lower temperature than that of the forward shock so it radiates at considerably lower frequencies. The reverse shock dominates the early optical emission, and an optical flash brighter than 15th magnitude, is expected together with the forward shock peak at x-rays or γ\gamma-rays. If this optical flash is not observed, strong limitations can be put on the baryonic contents of the relativistic shell deriving the GRBs, leading to a magnetically dominated energy density.Comment: 23 pages including 4 figure

    Family Effects in Youth Employment

    Get PDF
    The authors begin with the hypothesis that parental contacts play a major role in finding jobs for youth. This hypothesis is tested with a model of youth employment that includes characteristics of other family members in addition to a large set of control variables. Particular attention is paid to parental characteristics that might indicate a parent's ability to assist the youth in finding a job, including occupation, industry and education. The effects of such variables are generally not significant and do not support the initial hypothesis. However, the employment probability of a youth is significantly affected by the presence of employed siblings, indicating the presence of some intrafamily effects.

    Analysis of pressure distortion testing

    Get PDF
    The development of a distortion methodology, method D, was documented, and its application to steady state and unsteady data was demonstrated. Three methodologies based upon DIDENT, a NASA-LeRC distortion methodology based upon the parallel compressor model, were investigated by applying them to a set of steady state data. The best formulation was then applied to an independent data set. The good correlation achieved with this data set showed that method E, one of the above methodologies, is a viable concept. Unsteady data were analyzed by using the method E methodology. This analysis pointed out that the method E sensitivities are functions of pressure defect level as well as corrected speed and pattern

    Television, gas and electricity: Consuming comfort and leisure in the British home 1946–65

    Get PDF
    The arrival of television into the British home in the post-war period coincided with rising standards of comfort, provided by utilities such as gas and electricity and the devices that they powered. Television, in its capacity as a broadcast medium, was another utility flowing into the post-war home, providing domestic leisure. This article will explore how the material image of the television set became emblematic of the modern, leisure-based home, examining how it was used, in conjunction with gas and electricity, to construct an idealized comfortable home. This relationship was promoted in lifestyle magazines, advertisements, design publications and exhibitions. I will argue that from this relationship an idealized television lifestyle emerged, based around comfort and leisure, which was used to promote the consumption of gas and electricity, thus embedding television’s material form in consumer culture. In this way, the article will position the history of television in relation to the other utilities which shaped the home in this period, namely gas and electricity

    Importance of an Astrophysical Perspective for Textbook Relativity

    Get PDF
    The importance of a teaching a clear definition of the ``observer'' in special relativity is highlighted using a simple astrophysical example from the exciting current research area of ``Gamma-Ray Burst'' astrophysics. The example shows that a source moving relativistically toward a single observer at rest exhibits a time ``contraction'' rather than a ``dilation'' because the light travel time between the source and observer decreases with time. Astrophysical applications of special relativity complement idealized examples with real applications and very effectively exemplify the role of a finite light travel time.Comment: 5 pages TeX, European Journal of Physics, in pres
    corecore