1,638 research outputs found
Mass return to the interstellar medium from highly-evolved carbon stars
Data produced by the Infrared Astronomy Satellite (IRAS) was surveyed at the mid- and far-infrared wavelengths. Visually-identified carbon stars in the 12/25/60 micron color-color diagram were plotted, along with the location of a number of mass-losing stars that lie near the location of the carbon stars, but are not carbon rich. The final sample consisted of 619 objects, which were estimated to be contaminated by 7 % noncarbon-rich objects. The mass return rate was estimated for all evolved circumstellar envelopes. The IRAS Point Source Catalog (PSC) was also searched for the entire class of stars with excess emission. Mass-loss rates, lifetimes, and birthrates for evolved stars were also estimated
Some microstructural features of fatigue in an aluminium alloy
The microstructures produced by the heat treatment of a commercial
age hardening At-4.4 Cu alloy have been examined by thin foil electron
microscopy. Whilst there is similarity of the microstructures in the
commercial alloy to those which have been reported for simple binary At-Cu
alloys, there is a strong association of dislocation structures and incoherent
precipitates with undissolved Mn bearing intermetallic particles.
Fatigue tests made on the alloy at both 50 Hz and 20 kHz have shown that
there are changes in microstructure during fatigue; more markedly at 20 kHz
in which tests the heating effect has some importance. There is some
evidence of both accelerated ageing and also the by-passing or resolution
of coherent phases during fatigue, particular at 20 kHz
Study and applications of retrodirective and self adaptive electromagnetic-wave phase controls to a Mars probe
Computer analyses of retrodirective, and self adaptive antenna phase control techniques for Mars prob
Analysis of Small Water Management Structures in Irrigation Distribution Systems
The Irrigation and Drainage Research Conference conducted at Utah State University (ASCE, 1964) delineated many of the research needs regarding “Small Low- Cost Hydraulic Structures for Conveyance and Distribution Systems,” which was one of the six topics considered at the conference. In discussing possibilities for accomplishing the recommended research, it was suggested by some panel members that a considerable portion of the work could be undertaken by graduate students, particularly at the Master of Science level. The intent of this report has been to sort through the large volume of literature in an attempt to define the specific research needs regarding small water management structure used in irrigation distribution systems. In particular, the emphasis has been to develop specific research topics which could be accomplished as a thesis by a graduate student at the Master of Science level
Cosmic Evolution of a Sample of Infrared Luminous Galaxies
A sample of faint, southern-hemisphere 60 μm sources
(f_(60) > 100mJy) detected as part of the IRAS Additional Observations has been used, in conjunction with CCD imaging, to produce a list of faint infrared galaxies. Redshifts of this sample of galaxies can be compared
with model predictions for several evolutionary scenarios; the comparisons show an excess of galaxies at higher redshifts (z > 0.1) compared with the predictions of models which assume no evolution of the infrared-galaxy luminosity function
Coherent frequentism
By representing the range of fair betting odds according to a pair of
confidence set estimators, dual probability measures on parameter space called
frequentist posteriors secure the coherence of subjective inference without any
prior distribution. The closure of the set of expected losses corresponding to
the dual frequentist posteriors constrains decisions without arbitrarily
forcing optimization under all circumstances. This decision theory reduces to
those that maximize expected utility when the pair of frequentist posteriors is
induced by an exact or approximate confidence set estimator or when an
automatic reduction rule is applied to the pair. In such cases, the resulting
frequentist posterior is coherent in the sense that, as a probability
distribution of the parameter of interest, it satisfies the axioms of the
decision-theoretic and logic-theoretic systems typically cited in support of
the Bayesian posterior. Unlike the p-value, the confidence level of an interval
hypothesis derived from such a measure is suitable as an estimator of the
indicator of hypothesis truth since it converges in sample-space probability to
1 if the hypothesis is true or to 0 otherwise under general conditions.Comment: The confidence-measure theory of inference and decision is explicitly
extended to vector parameters of interest. The derivation of upper and lower
confidence levels from valid and nonconservative set estimators is formalize
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