2,895 research outputs found
Science and Religion: Stepping Toward the Light at the Mouth of the Cave
In analyzing the dialogue between science and religion, the author finds that it is hampered
by three semantic problems. The first denies, or at least undervalues, the two modes of
knowing most apropos to religion: the emotional and the intuitive/mystical modes. Secondly, the uncritical use of language causes considerable confusion. The third problem
limits discussion to what Stephan Schwartz has called the \"Grand Material Paradigm.\" As
the conclusion of the essay, a precis of an alternate cosmology is presented
The Dwarf Nova Outbursts of Nova Her 1960 (=V446 Her)
V446 Her is the best example of an old nova which has developed dwarf nova
eruptions in the post-nova state. We report on observed properties of the
long-term light curve of V446 Her, using photometry over 19 years. Yearly
averages of the outburst magnitudes shows a decline of ~0.013 mag/yr,
consistent with the decline of other post-novae that do not have dwarf nova
outbursts. Previous suggestions of bimodal distributions of the amplitudes and
widths of the outbursts are confirmed. The outbursts occur at a mean spacing of
18 days but the range of spacings is large (13-30 days). From simulations of
dwarf nova outbursts it has been predicted that the outburst spacing in V446
Her will increase as M-dot from the red dwarf companion slowly falls following
the nova; however the large intrinsic scatter in the spacings serves to hide
any evidence of this effect. We do find a systematic change in the outburst
pattern in which the brighter, wider type of outbursts disappeared after late
2003, and this phenomenon is suggested to be due to falling M-dot following the
nova.Comment: To appear at the Astronomical Journal; 7 pages, 1 table, 11 figure
Thermal shock and erosion resistant tantalum carbide ceramic material
Ceramic tantalum carbide artifacts with high thermal shock and mechanical erosion resistance are provided by incorporating tungsten-rhenium and carbon particles in a tantalum carbide matrix. The mix is sintered by hot pressing to form the ceramic article which has a high fracture strength relative to its elastic modulus and thus has an improved thermal shock and mechanical erosion resistance. The tantalum carbide is preferable less than minus 100 mesh, the carbon particles are preferable less than minus 100 mesh, and the tungsten-rhenium particles are preferable elongate, having a length to thickness ratio of at least 2/1. Tungsten-rhenium wire pieces are suitable as well as graphite particles
Thermal distortion analysis of a deployable parabolic reflector
A thermal distortion analysis of the ATS-6 Satellite parabolic reflector was performed using NASTRAN level 15.1. The same NASTRAN finite element method was used to conduct a one g static load analysis and a dynamic analysis of the reflector. In addition, a parametric study was made to determine which parameters had the greatest effect on the thermal distortions. The method used to model the construction of the reflector is described and the results of the analyses are presented
Combined high vacuum/high frequency fatigue tester
Apparatus permits application of significantly greater number of cycles or equivalent number of cycles in shorter time than conventional fatigue test machines. Environment eliminates problems associated with high temperature oxidation and with sensitivity of refractory alloy behavior to atmospheric contamination
Wind Variability in BZ Camelopardalis
(Shortened) Sequences of spectra of the nova-like cataclysmic variable (CV)
BZ Cam were acquired on 9 nights in 2005-2006 in order to study the time
development of episodes of wind activity known to occur frequently in this
star. We confirm past results that the P-Cygni absorption components of the
lines mostly evolve from a higher expansion velocity to lower velocity as an
episode progresses. We also commonly find blueshifted emission components in
the Halpha line profile, whose velocities and durations strongly suggest that
they are also due to the wind. We suggest that the progression from larger to
smaller expansion velocities is due the higher velocity portions of a wind
concentration moving beyond the edge of the continuum light of the disk first,
leaving a net redward shift of the remaining absorption profile. We also derive
a new orbital ephemeris for BZ Cam, using the radial velocity of the core of
the HeI 5876AA line, finding P = 0.15353(4). Using this period the wind
episodes in BZ Cam are found to be concentrated near inferior conjuction of the
emission line source. This result confirms that the winds in nova-like CVs are
often phase dependent, in spite of the puzzling implication that such winds
lack axisymmetry. We argue that the radiation-driven wind in BZ Cam receives an
initial boost by acting on gas that has been lifted above the disk by the
interaction of the accretion stream with the disk, thereby imposing flickering
time scales onto the wind events, as well as leading to an orbital modulation
of the wind due to the non-axisymmetric nature of the stream/disk interaction.Comment: The Astronomical Journal, in pres
Out of Sight, Out of Mind: Including Group Quarters Residents with Household Residents Can Change What We Know About Working-Age People with Disabilities
Information about residents of institutional and noninstitutional group quarters (GQ), particularly those with disabilities, has been limited by gaps in survey data, and statistics based on data that exclude some or all GQ residents are biased as estimates of total population statistics. We used the 2006 and 2007 American Community Survey (ACS) to identify the distribution of working-age populations with and without disabilities by major residence type, and to assess the sensitivity of disability statistics to GQ residence. Our findings showed that (1) of those with disabilities, about one in 13 males and one in 33 females live in GQ; (2) younger males with disabilities are more likely to reside there, particularly at institutional GQ; (3) individuals with and without disabilities who are black, American Indian, never married, or have less than a high school education had higher GQ residence rates; (4) 40% of male and 62% of female GQ residents have a disability; (5) adding GQ residents to household residents increases estimated disability prevalence for males by 6% and the estimated difference between disability prevalence rates by gender nearly disappears; and (6) inclusion of the GQ population substantively lowers employment rate estimates for males with disabilities—especially young blacks and American Indians
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