1,359 research outputs found
Monitoring dugongs within the Reef 2050 Integrated Monitoring and Reporting Program: final report of the dugong team in the megafauna expert group
The objectives of this report are to determine for the dugong:
An assessment of the current status of the relevant elements of the Great Barrier Reef (the Reef), including an evaluation of primary drivers, pressures and responses using the Driving Forces, Pressures, States, Impacts, Responses (DPSIR) Framework;
Identification of priority indicators for monitoring the key values associated with these elements;
Summary of potential sources of data;
Evaluation of adequacy of existing monitoring activities within each theme to achieve the objectives and requirements of RIMReP;
Recommendations for the design of an integrated monitoring program as a component of RIMReP, specifically considering:
The information requirements for each key element of the Reef to ensure that appropriate data and information are being collected to meet the fundamental objectives of RIMReP;
The spatial and temporal sampling design to ensure that greatest value can be extracted from the data collected;
The logistics of the design to ensure that it can be implemented efficiently;
Likely funding required to implement the recommended monitoring design.An accessible copy of this report is not yet available from this repository, please contact [email protected] for more information
Symmetry, bifurcation and stacking of the central configurations of the planar 1+4 body problem
In this work we are interested in the central configurations of the planar
1+4 body problem where the satellites have different infinitesimal masses and
two of them are diametrically opposite in a circle. We can think this problem
as a stacked central configuration too. We show that the configuration are
necessarily symmetric and the other sattelites has the same mass. Moreover we
proved that the number of central configuration in this case is in general one,
two or three and in the special case where the satellites diametrically
opposite have the same mass we proved that the number of central configuration
is one or two saying the exact value of the ratio of the masses that provides
this bifurcation.Comment: 9 pages, 2 figures. arXiv admin note: text overlap with
arXiv:1103.627
Orbits in the Field of a Gravitating Magnetic Monopole
Orbits of test particles and light rays are an important tool to study the
properties of space-time metrics. Here we systematically study the properties
of the gravitational field of a globally regular magnetic monopole in terms of
the geodesics of test particles and light. The gravitational field depends on
two dimensionless parameters, defined as ratios of the characteristic mass
scales present. For critical values of these parameters the resulting metric
coefficients develop a singular behavior, which has profound influence on the
properties of the resulting space-time and which is clearly reflected in the
orbits of the test particles and light rays.Comment: 24 pages, 15 figures. Accepted for publication in GR
Characterization of metal-insulator-semicomductor capacitors with insulating nitride films grown on 4H-SiC
ArticleJAPANESE JOURNAL OF APPLIED PHYSICS. 47(1):676-678(2008)journal articl
Geodesic equations and algebro-geometric methods
For an investigation of the physical properties of gravitational fields the
observation of massive test particles and light is very useful. The
characteristic features of a given space-time may be decoded by studying the
complete set of all possible geodesic motions. Such a thorough analysis can be
accomplished most effectively by using analytical methods to solve the geodesic
equation. In this contribution, the use of elliptic functions and their
generalizations for solving the geodesic equation in a wide range of well known
space-times, which are part of the general Pleba\'nski-Demia\'nski family of
solutions, will be presented. In addition, the definition and calculation of
observable effects like the perihelion shift will be presented and further
applications of the presented methods will be outlined.Comment: 8 pages, no figures; based on presentation at the conference
"Relativity and Gravitation: 100 Years after Einstein in Prague," Prague,
2012. Relativity and Gravitation, volume 157 of Springer Proceedings in
Physics, p 91. Springer International Publishing, 201
Orientation dependence of the wear resistance in the CoâCrâMo single crystal
This is the report clarifying the orientation dependence of the wear behavior of CoâCrâMo alloy. The wear resistance of the CoâCrâMo alloy with face-centered cubic (fcc) structure was found to be higher on the planes in order of {110}, {001} and {111}. Quantitatively, the wear resistance on {110} is 1.5 times larger than that on {111}. The tendency showed in coincident with the orientation dependence of the surface hardness, as empirically suggested. However, we additionally found in the observation of the worn surface in the fcc-single crystals that the volume fraction of the hexagonal close-packed (hcp)-phase, which was formed as the strain-induced martensite during the wear test, was larger in the same order of the wear resistance. The variation in formation frequency of the hcp-phase during the wear test can be explained by focusing on the Schmid factor along the resultant direction of the applied stress and the friction stress. On the {111} surface where the Schmid factor for the strain-induced Δ-martensite formation is small, homogeneous deformation microstructure covered by it was not developed even after long-time wear, resulting in lower wear resistance. The results strongly suggest that not only the hardness, but the distribution of the Δ-martensite is important to control the wear behavior of the CoâCr alloys with the extremely low stacking fault energy, and it can be achieved by the crystal orientation control in the Îł-phase.Nakano T., Hagihara K., Ribeiro A.R., et al. Orientation dependence of the wear resistance in the CoâCrâMo single crystal. Wear, 478-479, 203758. https://doi.org/10.1016/j.wear.2021.203758
A Study of the Orbits of the Logarithmic Potential for Galaxies
The logarithmic potential is of great interest and relevance in the study of
the dynamics of galaxies. Some small corrections to the work of Contopoulos &
Seimenis (1990) who used the method of Prendergast (1982) to find periodic
orbits and bifurcations within such a potential are presented. The solution of
the orbital radial equation for the purely radial logarithmic potential is then
considered using the p-ellipse (precessing ellipse) method pioneered by Struck
(2006). This differential orbital equation is a special case of the generalized
Burgers equation. The apsidal angle is also determined, both numerically as
well as analytically by means of the Lambert W and the Polylogarithm functions.
The use of these functions in computing the gravitational lensing produced by
logarithmic potentials is discussed.Comment: 12 pages, 4 figures. Accepted by MNRAS Sept 6 201
Energy Spectra of the Soft X-ray Diffuse Emission in Fourteen Fields Observed with Suzaku
The soft diffuse X-ray emission of twelve fields observed with Suzaku are
presented together with two additional fields from previous analyses. All have
galactic longitudes 65 deg < l < 295 deg to avoid contributions from the very
bright diffuse source that extends at least 30 deg from the Galactic center.
The surface brightnesses of the Suzaku nine fields for which apparently
uncontaminated ROSAT All Sky Survey (RASS) were available were statistically
consistent with the RASS values, with an upper limit for differences of 17 x
10^{-6} c s^{-1} amin^{-2} in R45}-band. The Ovii and Oviii intensities are
well correlated to each other, and Ovii emission shows an intensity floor at ~2
photons s^{-1} cm^{-2 str^{-1} (LU). The high-latitude Oviii emission shows a
tight correlation with excess of Ovii emission above the floor, with (Oviii
intensity) = 0.5 x [(Ovii intensity) -2 LU], suggesting that temperatures
averaged over different line-of-sight show a narrow distribution around ~0.2
keV. We consider that the offset intensity of Ovii arises from the Heliospheric
solar wind charge exchange and perhaps from the local hot bubble, and that the
excess Ovii (2-7 LU) is emission from more distant parts of the Galaxy. The
total bolometric luminosity of this galactic emission is estimated to be 4 x
10^{39} erg s^{-1}, and its characteristic temperature may be related to the
virial temperature of the Galaxy.Comment: 22 Pages, 8 figures, to appear in PASJ (Vol.61 No.4
Linear stability of the Lagrangian triangle solutions for quasihomogeneous potentials
In this paper we study the linear stability of the relative equilibria for
homogeneous and quasihomogeneous potentials. Firstly, in the case the potential
is a homogeneous function of degree , we find that any relative equilibrium
of the -body problem with is spectrally unstable. We also find a
similar condition in the quasihomogeneous case. Then we consider the case of
three bodies and we study the stability of the equilateral triangle relative
equilibria. In the case of homogeneous potentials we recover the classical
result obtained by Routh in a simpler way. In the case of quasihomogeneous
potentials we find a generalization of Routh inequality and we show that, for
certain values of the masses, the stability of the relative equilibria depends
on the size of the configuration.Comment: 21 pages 4 figure
- âŠ