A Semi-Empirical Interpretation of the Period-Luminosity Relation of Variable Stars

1959 ◽  
Vol 71 ◽  
pp. 220 ◽  
Author(s):  
S.-S. Huang
Author(s):  
Roger Hurst ◽  
Valerio Bicego ◽  
Jude Foulds

The small punch or disk bend test has particular value in life prediction of operating equipment since the test requires very small amounts of material (a common test specimen disk is 0.5 mm thick with a diameter of 6 to 10 mm), and usually the required volume of material can be acquired from operating equipment in a virtually nondestructive manner. The application of the small punch (SP) test for creep has gained significant interest in the last decade, primarily as a result of research in Europe. The CEN (one of three European standardization organizations recognized by the EC) has been working to develop a Code of Practice for the small punch test. The Code documents, very recently completed, focus on use of the test for creep rupture and tensile and toughness properties. This paper summarizes the European round-robin work leading to the Code of Practice and key aspects of the Code. Included is a description of the currently recommended semi-empirical interpretation of data from the multiaxially-loaded small punch test specimens, less straightforward than that from conventional uniaxial specimens. As the SP test sees more field use and as the specimen and test configurations achieve better uniformity, we can expect that its application to creep life prediction will increase.


1967 ◽  
Vol 28 ◽  
pp. 207-244
Author(s):  
R. P. Kraft

(Ed. note:Encouraged by the success of the more informal approach in Christy's presentation, we tried an even more extreme experiment in this session, I-D. In essence, Kraft held the floor continuously all morning, and for the hour and a half afternoon session, serving as a combined Summary-Introductory speaker and a marathon-moderator of a running discussion on the line spectrum of cepheids. There was almost continuous interruption of his presentation; and most points raised from the floor were followed through in detail, no matter how digressive to the main presentation. This approach turned out to be much too extreme. It is wearing on the speaker, and the other members of the symposium feel more like an audience and less like participants in a dissective discussion. Because Kraft presented a compendious collection of empirical information, and, based on it, an exceedingly novel series of suggestions on the cepheid problem, these defects were probably aggravated by the first and alleviated by the second. I am much indebted to Kraft for working with me on a preliminary editing, to try to delete the side-excursions and to retain coherence about the main points. As usual, however, all responsibility for defects in final editing is wholly my own.)


1967 ◽  
Vol 28 ◽  
pp. 177-206
Author(s):  
J. B. Oke ◽  
C. A. Whitney

Pecker:The topic to be considered today is the continuous spectrum of certain stars, whose variability we attribute to a pulsation of some part of their structure. Obviously, this continuous spectrum provides a test of the pulsation theory to the extent that the continuum is completely and accurately observed and that we can analyse it to infer the structure of the star producing it. The continuum is one of the two possible spectral observations; the other is the line spectrum. It is obvious that from studies of the continuum alone, we obtain no direct information on the velocity fields in the star. We obtain information only on the thermodynamic structure of the photospheric layers of these stars–the photospheric layers being defined as those from which the observed continuum directly arises. So the problems arising in a study of the continuum are of two general kinds: completeness of observation, and adequacy of diagnostic interpretation. I will make a few comments on these, then turn the meeting over to Oke and Whitney.


1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.


1999 ◽  
Vol 190 ◽  
pp. 561-562
Author(s):  
G. P. Di Benedetto

An accurate calibration of the surface brightness scaleSVas a function of the near-IR color (V–K) has been recently measured for non-variable Galactic dwarf and giant stars. It can be shown that this correlation can be applied to theSVscale of Galactic Cepheid variable stars, which are of major cosmological interest.


Author(s):  
David H. Levy ◽  
Janet A. Mattei
Keyword(s):  

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