11,561 research outputs found
The in situ measurement of lunar thermal conductivity
Theory and model calculations for heat flow measurements at lunar site using cylindrical ring sourc
Some calculations pertaining to the feasibility of measuring lunar heat flow Final report
Measuring lunar heat flow at surface or in shallow hole - study of steady periodic temperatures, steady state flux perturbation, and blanket measurement metho
X-Ray Diffraction and Reflectance Spectroscopy of Murchison Powders (CM2) After Thermal Analysis Under Reducing Conditions to Final Temperatures Between 300 and 1300c
The asteroids Ryugu and Bennu have spectral characteristics in common with CI/CM type carbonaceous chondrites and are target bodies for JAXAs Hayabusa2 and NASAs OSIRIS-Rex missions, respectively. Analog studies, based primarily on the Murchison CM2 chondrite, provide a pathway to separate spectral properties resulting space weathering from those inherent to parent-body, mineralogy, chemistry, and processes. Ryugu shares spectral properties with thermally metamorphosed and partly dehydrated CI/CM chondrites. We have undertaken a multidisciplinary study of the thermal decomposition of Murchison powder samples as an analog to metamorphic process that may have occurred on Ryugu. Bulk analyses include thermal And evolved gas analysis, X-ray diffraction (XRD), and VIS-NIR and Mssbauer spectroscopy; micro- to nanoscale analyses included scanning and transmission electron microscopy and electron probe micro analysisWe report here XRD and VIS-NIR analyses of pre- and post-heated Murchison powders, and in a companion paper report results from multiple electron beam techniques
AUSSAT battery life test program
AUSSAT Pty. Ltd., the Australian National Satellite organization, has contracted with the Hughes Aircraft Company (HAC) for the construction of 3 satellites based on the now familiar HS-376 product line. As part of the AUSSAT contract, HAC is conducting an extensive NiCd battery life test program. The life test program, objectives and test results to date are described. Particular emphasis is given to the evaluation of the FS2117 separator as a future replacement for the Pellon 2505 separator of which only a very limited quantity remains
Resistivity peak values at transition between fractional quantum Hall states
Experimental data available in the literature for peak values of the diagonal
resistivity in the transitions between fractional quantum Hall states are
compared with the theoretical predictions. It is found that the majority of the
peak values are close to the theoretical values for two-dimensional systems
with moderate mobilities.Comment: 3 pages, 1 figur
Variant supercurrent multiplets
In N = 1 rigid supersymmetric theories, there exist three standard
realizations of the supercurrent multiplet corresponding to the (i) old
minimal, (ii) new minimal and (iii) non-minimal off-shell formulations for N =
1 supergravity. Recently, Komargodski and Seiberg in arXiv:1002.2228 put
forward a new supercurrent and proved its consistency, although in the past it
was believed not to exist. In this paper, three new variant supercurrent
multiplets are proposed. Implications for supergravity-matter systems are
discussed.Comment: 11 pages; V2: minor changes in sect. 3; V3: published version; V4:
typos in eq. (2.3) corrected; V5: comments and references adde
Young star clusters in M31
In our study of M31's globular cluster system with MMT/Hectospec, we have
obtained high-quality spectra of 85 clusters with ages less than 1 Gyr. With
the exception of Hubble V, the young cluster in NGC 205, we find that these
young clusters have kinematics and spatial distribution consistent with
membership in M31's young disk. Preliminary estimates of the cluster masses and
structural parameters, using spectroscopically derived ages and HST imaging,
confirms earlier suggestions that M31 has clusters similar to the LMC's young
populous clusters.Comment: 4 pages, 1 figure, contributed talk at "Galaxies in the Local Volume"
conference in Sydney, July 200
A reaction-diffusion model for the growth of avascular tumor
A nutrient-limited model for avascular cancer growth including cell
proliferation, motility and death is presented. The model qualitatively
reproduces commonly observed morphologies for primary tumors, and the simulated
patterns are characterized by its gyration radius, total number of cancer
cells, and number of cells on tumor periphery. These very distinct
morphological patterns follow Gompertz growth curves, but exhibit different
scaling laws for their surfaces. Also, the simulated tumors incorporate a
spatial structure composed of a central necrotic core, an inner rim of
quiescent cells and a narrow outer shell of proliferating cells in agreement
with biological data. Finally, our results indicate that the competition for
nutrients among normal and cancer cells may be a determinant factor in
generating papillary tumor morphology.Comment: 9 pages, 6 figures, to appear in PR
Robot rights? Towards a social-relational justification of moral consideration \ud
Should we grant rights to artificially intelligent robots? Most current and near-future robots do not meet the hard criteria set by deontological and utilitarian theory. Virtue ethics can avoid this problem with its indirect approach. However, both direct and indirect arguments for moral consideration rest on ontological features of entities, an approach which incurs several problems. In response to these difficulties, this paper taps into a different conceptual resource in order to be able to grant some degree of moral consideration to some intelligent social robots: it sketches a novel argument for moral consideration based on social relations. It is shown that to further develop this argument we need to revise our existing ontological and social-political frameworks. It is suggested that we need a social ecology, which may be developed by engaging with Western ecology and Eastern worldviews. Although this relational turn raises many difficult issues and requires more work, this paper provides a rough outline of an alternative approach to moral consideration that can assist us in shaping our relations to intelligent robots and, by extension, to all artificial and biological entities that appear to us as more than instruments for our human purpose
Binary Neutron-Star Systems: From the Newtonian Regime to the Last Stable Orbit
We report on the first calculations of fully relativistic binary circular
orbits to span a range of separation distances from the innermost stable
circular orbit (ISCO), deeply inside the strong field regime, to a distance
( 200 km) where the system is accurately described by Newtonian dynamics.
We consider a binary system composed of two identical corotating neutron stars,
with 1.43 gravitational mass each in isolation. Using a conformally
flat spatial metric we find solutions to the initial value equations that
correspond to semi-stable circular orbits. At large distance, our numerical
results agree exceedingly well with the Newtonian limit. We also present a self
consistent determination of the ISCO for different stellar masses.Comment: 4 pages, 3 postscript figures. Data points added to fig 2; some
issues clarified; references adde
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