948 research outputs found
Fluidic Plasma Display Study, Phase 3 Quarterly Report
Crosstalk problems and cross grid control, and experimental hardware design for fluidically controlled plasma display device
End user development: Satisfaction with tools and satisfaction with applications
This study explored the relationship between end user developers’ perceptions of their applications and their perceptions of the tools used to create them. Satisfaction with a user developed application was found to be significantly correlated with satisfaction with the tool used to create the application. The role of experience in this relationship was also explored, and possible implications of the findings are discussed
Fluidic plasma display study, phase 3 Final report
Fluidic plasma display device
Fluidic plasma display study, phase 2 Final report, 10 May 1968 - 21 Mar. 1969
Fluidic systems for control of matrix plasma display
Fluidic decoder and display device
Feasibility and advantages of spacecraft fluidic decoder and display devic
Cosmological simulations in MOND: the cluster scale halo mass function with light sterile neutrinos
We use our Modified Newtonian Dynamics (MOND) cosmological particle-mesh
N-body code to investigate the feasibility of structure formation in a
framework involving MOND and light sterile neutrinos in the mass range 11 - 300
eV: always assuming that \Omega_{\nu_s}=0.225 for H_o=72 \kms Mpc^{-1}. We run
a suite of simulations with variants on the expansion history, cosmological
variation of the MOND acceleration constant, different normalisations of the
power spectrum of the initial perturbations and interpolating functions. Using
various box sizes, but typically with ones of length 256 Mpc/h, we compare our
simulated halo mass functions with observed cluster mass functions and show
that (i) the sterile neutrino mass must be larger than 30 eV to account for the
low mass (M_{200}<10^{14.6} solar masses) clusters of galaxies in MOND and (ii)
regardless of sterile neutrino mass or any of the variations we mentioned
above, it is not possible to form the correct number of high mass
(M_{200}>10^{15.1} solar masses) clusters of galaxies: there is always a
considerable over production. This means that the ansatz of considering the
weak-field limit of MOND together with a component of light sterile neutrinos
to form structure from z ~ 200 fails. If MOND is the correct description of
weak-field gravitational dynamics, it could mean that subtle effects of the
additional fields in covariant theories of MOND render the ansatz inaccurate,
or that the gravity generated by light sterile neutrinos (or by similar hot
dark matter particles) is different from that generated by the baryons.Comment: 10 pages, 9 figures, accepted for publication in MNRA
Detection of X-ray line emission from the shell of SNR B0540-69.3 with XMM-Newton RGS
We present X-ray observations of PSR 0540-69.3 with the XMM-Newton
observatory. The spectra obtained with the Reflection Grating Spectrometer
reveal, for the first time, emission from ionized species of O, Ne and Fe
originating from the SNR shell. Analysis of the emission line spectrum allows
us to derive estimates of the temperature, ionization timescale, abundances,
location, and velocity of the emitting gas.Comment: 5 pages, 5 figures, accepted for publication in Astronomy and
Astrophysics, letters (XMM issue
N-body simulations of the Carina dSph in MOND
The classical dwarf spheroidals (dSphs) provide a critical test for Modified
Newtonian Dynamics (MOND) because they are observable satellite galactic
systems with low internal accelerations and low, but periodically varying,
external acceleration. This varying external gravitational field is not
commonly found acting on systems with low internal acceleration. Using Jeans
modelling, Carina in particular has been demonstrated to require a V-band
mass-to-light ratio greater than 5, which is the nominal upper limit for an
ancient stellar population. We run MOND N-body simulations of a Carina-like
dSph orbiting the Milky Way to test if dSphs in MOND are stable to tidal forces
over the Hubble time and if those same tidal forces artificially inflate their
velocity dispersions and therefore their apparent mass-to-light ratio. We run
many simulations with various initial total masses for Carina, and
Galactocentric orbits (consistent with proper motions), and compare the
simulation line of sight velocity dispersions (losVDs) with the observed losVDs
of Walker et al. (2007). We find that the dSphs are stable, but that the tidal
forces are not conducive to artificially inflating the losVDs. Furthermore, the
range of mass-to-light ratios that best reproduces the observed line of sight
velocity dispersions of Carina is 5.3 to 5.7 and circular orbits are preferred
to plunging orbits. Therefore, some tension still exists between the required
mass-to-light ratio for the Carina dSph in MOND and those expected from stellar
population synthesis models. It remains to be seen whether a careful treatment
of the binary population or triaxiality might reduce this tension.Comment: 17 pages, 12 figures, accepted for publication in MNRA
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The 2010 Winter Olympics: A Mixed-Methods Investigation of the Hotel Industry and Tourism in the Demographic Clusters metro–Vancouver versus the alpine–Resort Whistler
In this thesis, applying an innovative postmodern equal-weight/sequential QUAN→PHEN Mixed-Methods Phenomenological Research (‘MMPR’) approach to study an Olympics’ impact within its two-cluster socio-demographic footprint forms its main contribution to knowledge. Facilitating between-methods triangulation is a novel eclectic pragmatic approach that is used to capture the richness of thematic data flowing from in-depth, open-ended interviews with most – 62 in all – senior Hoteliers spread evenly between distinct urban Metro-Vancouver and rural alpine-Whistler, whilst concurrently capitalizing on the availability of a unique BC Stats proprietary micro-municipal-level secondary data source, i.e., British Columbia’s ‘Additional Hotel Room Tax’ (‘AHRT’). Typically, traditional mono-method-positivist neo-classical economic syntheses are used to quantify an Olympic Games’ ex-ante or ex-post impact. This study’s findings confirm that such syntheses attempts, at the micro-municipal level, lead to inevitable dead-ends. At a sub-national level of micro-granularity, using available economic models is an impossible task due to the insurmountable practical problem of complete lack of, or paucity, of data. When applied to assess mega-events, such modelling is shown to lack credibility; models are insufficiently comprehensive or its users consciously engage in ‘shenanigans’ by force-fitting input/output to produce pre-ordained outcomes for political expedience and meeting agency interests. The ‘MMPR’ approach acknowledges and respects the established and ‘current-thinking’ paradigmatic epistemological and ontological perspectives. ‘Hotel Activity’, measured via ‘AHRT’, is substituted as a ‘Proxy’ for ‘Tourism’ following empirically establishing these three variables as highly correlated. Prevalent academic findings of negative impacts from Winter Olympics are not borne out. Phenomenological issues of ‘illusory correlations’ and ‘data saturation’ are addressed
Synoptic study of the SMC SNRs using XMM-Newton
We present a detailed X-ray spectral analysis of 13 supernova remnants (SNR)
in the Small Magellanic Cloud (SMC). We apply both single-temperature
non-equilibrium ionisation models and models based on the Sedov similarity
solution, where applicable. We also present detailed X-ray images of individual
SNRs, which reveal a range of different morphological features. Eight remnants,
viz DEM S 32, IKT 2, HFPK 419, IKT 6, IKT 16, IKT 18 and IKT 23, are consistent
with being in their Sedov evolutionary phase. IKT 6 and IKT 23 both have a
clear shell like morphology with oxygen-rich X-ray emitting material in the
centre. We draw attention to similarities between these two remnants and the
well studied, oxygen-rich remnant IKT 22 (SNR 0102-72.3) and propose that they
are more evolved versions of IKT 22. IKT 4, IKT 5, DEM S 128 and IKT 5 are
evolved remnants which are in, or in the process of entering, the radiative
cooling stage. We argue that the X-ray emission from these four remnants is
most likely from the ejecta remains of type Ia SNe. Our modeling allow us to
derive estimates for physical parameters, such as densities, ages, masses and
initial explosion energies. Our results indicate that the average SMC hydrogen
density is a factor of ~6 lower as compared to the Large Magellanic Cloud. This
has obvious implications for the evolution and luminosities of the SMC SNRs. We
also estimate the average SMC gas phase abundances for the elements O, Ne, Mg,
Si and Fe.Comment: submitted to A&
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