15,347 research outputs found
[Letter from Alex Bradford to Lieutenant and Mrs. Ray Starner - November 4, 1940]
No full textLetter from Alex Bradford to Lieutenant and Mrs. Ray Starner describing the the current state of affairs that the author was experiencing, including: the London blitz, the moral of the troops on the ground, and the collective company of men opposing the Nazi regime
The effect of different magnetospheric structures on predictions of gamma-ray pulsar light curves
No full textThe second pulsar catalogue of the Fermi Large Area Telescope (LAT) will contain
in excess of 100 gamma-ray pulsars. The light curves (LCs) of these pulsars exhibit a variety
of shapes, and also different relative phase lags with respect to their radio pulses, hinting at
distinct underlying emission properties (e.g., inclination and observer angles) for the individual
pulsars. Detailed geometric modelling of the radio and gamma-ray LCs may provide constraints
on the B-field structure and emission geometry. We used different B-field solutions, including
the static vacuum dipole and the retarded vacuum dipole, in conjunction with an existing
geometric modelling code, and constructed radiation sky maps and LCs for several different
pulsar parameters. Standard emission geometries were assumed, namely the two-pole caustic
(TPC) and outer gap (OG) models. The sky maps and LCs of the various B-field and radiation
model combinations were compared to study their effect on the resulting LCs. As an application,
we compared our model LCs with Fermi LAT data for the Vela pulsar, and inferred the most
probable configuration in this case, thereby constraining Vela’s high-altitude magnetic structure
and system geometr
The effect of different magnetospheric structures on predictions of gamma-ray pulsar light curves
No full textThe second pulsar catalogue of the Fermi Large Area Telescope (LAT) will contain in excess of 100 gamma-ray pulsars. The light curves (LCs) of these pulsars exhibit a variety of shapes, and also different relative phase lags with respect to their radio pulses, hinting at distinct underlying magnetospheric geometries and emission properties for the individual pulsars. Detailed geometric modelling of the radio and gamma-ray LCs may provide constraints on the B-field structure and emission geometry. We used different B-field solutions in conjunction with an existing geometric modelling code, including the static vacuum dipole, the retarded vacuum dipole, and offset-dipole solutions, and constructed radiation sky maps and LCs for several different pulsar parameters. Standard emission geometries were assumed, namely the Two-Pole Caustic (TPC) and Outer Gap (OG) models. The sky maps and LCs of the various B-field and radiation model combinations were compared to study their effect on the resulting LCs. As an application, we compared our model LCs with Fermi LAT data for the Vela pulsar, and inferred the most probable configuration in this case, thereby constraining Vela’s high-altitude magnetic structure and system geometry.South African National Research Foundation (NRF
The student's guide to completing an author study
No full textThe 'Student's guide to completing an author study' emerged during the early development of the school library resource center program at Glen Stewart Elementary School in Stratford Canada on Prince Edward Island. This research process centered on an author study, with direct teaching and clear assignment. The resulting model has been adapted to various grade levels and subject areas in different schools.Source type: Electronic(1)http://proquest.umi.com/pqdweb?did=49237063&Fmt=7&clientId=65345&RQT=309&VName=PQ
Active X-ray optics for the next generation of X-ray space telescopes
No full textDescribed within is the design, manufacture, metrology and X-ray testing of an active X-ray
prototype intended for the next generation of X-ray telescopes. One of the challenges faced by
the X-ray telescope community is how to combine high resolution and high sensitivity into one
system, as weight limitations place constraints on the optics that can be launched. Therefore the
mandate of the active X-ray prototype is to provide high sensitivity through the ability of the optics
to be nested and to deliver high angular resolution through the active control of the optic’s form.
Piezoelectric unimorph actuators provide the active component: it is intended that they will correct
for figure errors within the optic and therefore increase the angular resolution capability.
The prototype’s design is based upon an ellipsoidal segment which provides point-to-point
focussing of an X-ray source. The prototype itself is composed of an electroformed nickel optic
where the non-reflective surface is populated with 30 piezoelectric actuators and it is the production
of the prototype that is the core of the presented research. Metrology of the actuators’ influence
functions is presented and highlight the prototype’s ability to deform its optic surface by microns.
In addition, the measured influence functions are compared against finite element models and a
distinct similarity between the functions is observed.
The prototype was tested at an X-ray beamline facility in November 2008 and the results
showed the prototype’s ability to correct the optic to achieve an improved angular resolution: from
0.786 arc-minutes to 0.686 arc-minutes in terms of full width half maximum. Finally, difficulties
in the manufacture of the prototype and X-ray testing shall be presented alongside future work in
conclusion to this thesis
The effect of a resistance training program on the grab, track and swing starts in swimming
No full textThe study aims to establish the effectiveness of the grab, swing and rear-weighted track starts in swimming.Master of Applied Scienc
The effect of an offset-dipole magnetic field on the Vela pulsar’s γ-ray light curves
No full textOver the past six years, the Fermi Large Area Telescope has detected more than
150 γ-ray pulsars, discovering a variety of light curve trends and classes. Such diversity hints
at distinct underlying magnetospheric and/or emission geometries. We implemented an offsetdipole magnetic field, with an offset characterised by parameters epsilon and magnetic azimuthal
angle, in an existing geometric pulsar modelling code which already includes static and retarded
vacuum dipole fields. We use these different B-field solutions in conjunction with standard
emission geometries, namely the two-pole caustic and outer gap models (the latter only for
non-offset dipoles), and construct intensity maps and light curves for several pulsar parameters.
We compare our model light curves to the Vela data from the second pulsar catalogue of Fermi.
We use a refined chi-square grid search method for finding best-fit light curves for each of the
different models. Our best fit is for the retarded vacuum dipole field and the outer gap mode
Author, Geraldine Brooks at the National Library of Australia for the 2009 Ray Mathew Lecture, Canberra, 23 October 2009 [picture] /
No full textTitle from acquisitions documentation.; Part of the collection: Portraits of author, Geraldine Brooks during her visit to the National Library of Australia for the 2009 Ray Mathew Lecture, Canberra, 23 October 2009.; Acquired in digital format; access copy available online.; Mode of access: Internet via World Wide Web.; Photographed by a staff member of the National Library of Australia
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
Papers of Peggy Ray
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/65009Photocopies of reviews from newspapers (unspecified except for that from "Farrago", 13 July 1949) of The Tin Alley Players' production of Noel Coward's "This Happy Breed" at the Union theatre. It was produced by Elden de Steiger, with Peggy Ray, Gwen Reid, Yetta Rothberg, Keith McKenzie and Peggy Haynes in the cast. Also: a review by "L.M." of T.S. Eliot's "Family Reunion", with cast including David Goodall, Frank Brooks, Peggy Tellick and Stanley Lowe.113470
Acquisition: [1991.0105] "Papers of Peggy Ray
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