Methods of Measurement and Reduction of Spectrograms for the Determination of Radial Velocities

1907 ◽  
Vol 19 ◽  
pp. 13
Author(s):  
J. H. Moore
Keyword(s):  
Radial Velocities ◽  
Methods Of Measurement

The Elastic Coefficients of the Theory of Consolidation

1957 ◽  
Vol 24 (4) ◽  
pp. 594-601
Author(s):  
M. A. Biot ◽  
D. G. Willis
Keyword(s):  
Nonlinear Systems ◽  
Shear Modulus ◽  
Physical Interpretation ◽  
Compressible Fluid ◽  
Elastic Solid ◽  
Fluid Content ◽  
Alternate Forms ◽  
Elastic Coefficients ◽  
Methods Of Measurement

Abstract The theory of the deformation of a porous elastic solid containing a compressible fluid has been established by Biot. In this paper, methods of measurement are described for the determination of the elastic coefficients of the theory. The physical interpretation of the coefficients in various alternate forms is also discussed. Any combination of measurements which is sufficient to fix the properties of the system may be used to determine the coefficients. For an isotropic system, in which there are four coefficients, the four measurements of shear modulus, jacketed and unjacketed compressibility, and coefficient of fluid content, together with a measurement of porosity appear to be the most convenient. The porosity is not required if the variables and coefficients are expressed in the proper way. The coefficient of fluid content is a measure of the volume of fluid entering the pores of a solid sample during an unjacketed compressibility test. The stress-strain relations may be expressed in terms of the stresses and strains produced during the various measurements, to give four expressions relating the measured coefficients to the original coefficients of the consolidation theory. The same method is easily extended to cases of anisotropy. The theory is directly applicable to linear systems but also may be applied to incremental variations in nonlinear systems provided the stresses are defined properly.

A Proposed Method for the Determination of Radial Velocities of Stars

1906 ◽  
Vol 23 ◽  
pp. 148 ◽  
Author(s):  
George C. Comstock
Keyword(s):  
Radial Velocities

Note on the Determination of Radial Velocities of Nebulae

1913 ◽  
Vol 25 ◽  
pp. 288
Author(s):  
W. W. Campbell
Keyword(s):  
Radial Velocities

scholarly journals Formation Depths of Spectral Lines in Cepheids

1995 ◽  
Vol 155 ◽  
pp. 373-374
Author(s):  
Michael D. Albrow ◽  
P. L. Cottrell
Keyword(s):  
Spectral Line ◽  
Velocity Fields ◽  
Radial Velocities ◽  
Spectral Lines ◽  
Line Formation ◽  
Ionisation Potential ◽  
Velocity Gradients ◽  
Different Levels ◽  
Line Depth

There has been a number of observational programmes that have endeavoured to investigate the atmospheric velocity fields in Cepheids (e.g., Sanford 1956, Wallerstein et al. 1992, Butler 1993). These studies measured the radial velocities of lines of different strength, excitation and ionisation potential as these provide an indication of line formation at different levels in the atmosphere. From these measurements, the presence of velocity gradients can be inferred, but determination of the magnitude of such gradients requires knowledge of the spectral line depth of formation. Through dynamical modelling we are endeavouring to ascertain what is actually being measured in the above observational programmes.

scholarly journals A Determination of Secular Parallaxes of Reference Stars from Relative Proper Motions of Open Clusters

1970 ◽  
Vol 7 ◽  
pp. 74-76
Author(s):  
A. N. Deutsch
Keyword(s):  
Systematic Errors ◽  
Open Clusters ◽  
Radial Velocities ◽  
Proper Motions ◽  
The Mean

The determination of secular parallaxes of stars is usually based on meridian observations of proper motions of bright stars, this introducing known systematic errors. The mean parallaxes of stars can be obtained by means of radial velocities which are known for the bright stars. The more perspective method, the reference of stars to galaxies, is not applicable at low galactic latitudes.

scholarly journals A new differential dilatometer for the determination of volume changes during solidification

1927 ◽  
Vol 115 (772) ◽  
pp. 554-570
Keyword(s):  
Melting Point ◽  
Linear Expansion ◽  
Experimental Methods ◽  
Eutectic Alloys ◽  
Volume Changes ◽  
Hydrostatic Method ◽  
The Subject ◽  
New Form ◽  
Methods Of Measurement

In recent years, the practical requirements of the metal industries have made it necessary to study the factors which govern the production of good castings. One of the most important of these factors is the change of volume which accompanies solidification. The experimental methods which have hitherto been used to determine this change have given discordant results, and it has seemed desirable to devise a new method, less liable to error. The new form of volumenometer which is the subject of this paper is intended to eliminate most of the errors inherent in the older methods. It has been applied to the measurement of the volume changes of two eutectic alloys, those of lead and tin and of tin and bismuth, the former of which contracts during solidification, whilst the latter shows a distinct expansion. The results indicate that the method is trustworthy. Previous Methods of Measurement . The older methods, which have been used for the experimental determination of the changes in volume, associated with the change in state of bodies, may be divided into the following classes:— ( a )The coefficients of expansion of the solid and liquid, over limited ranges of temperature, are measured and the volume change occurring at the melting point is found by extrapolation. The coefficient of expansion of the solid is found either by direct measurement of the linear expansion or deduced from measurements derived from some hydrostatic method in which Archimedes’ Principle is employed. The expansion of the liquid melt is inferred from observations on some dilatometric or hydrostatic method.

A determination of the apex and velocity of the solar motion from radial velocities of stars of spectral type B

1924 ◽  
Vol 222 (8) ◽  
pp. 113-122
Author(s):  
B. Fessenkoff ◽  
C. Ogrodnikoff
Keyword(s):  
Spectral Type ◽  
Radial Velocities ◽  
Type B ◽  
Solar Motion
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